nanostructured materials for electrochromic devices

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高密度阳极铝电解槽电

第 54 卷第 2 期2023 年 2 月中南大学学报(自然科学版)Journal of Central South University (Science and Technology)V ol.54 No.2Feb. 2023高密度阳极铝电解槽电−热场耦合仿真研究魏兴国1，廖成志1，侯文渊1, 2，段鹏1，李贺松1(1. 中南大学能源科学与工程学院，湖南长沙，410083；2. 中北大学能源与动力工程学院，山西太原，030051)摘要：在铝电解槽中，阳极炭块内存在的气孔会降低炭块的导电和导热性能，并且增加炭渣，降低电流效率，导致炭耗和直流电耗升高。

通过浸渍工艺得到的高密度阳极可以有效地降低炭块的气孔率。

为了探究高密度阳极铝电解槽的电−热场变化和影响，基于ANSYS 软件建立高密度阳极铝电解槽的电−热场耦合计算模型。

研究结果表明：铝电解槽高密度阳极炭块的平均温度上升8.73 ℃，热应力增加，但形变量减小；侧部槽壳的平均温度下降28.59 ℃，热应力和形变量均降低，有利于保持槽膛内形稳定；热场变化主要与阳极炭块物性改变有关；槽电压降低49.16 mV ，主要与炭块物性改变和电解质电阻率降低有关；高密度阳极电流全导通时间缩短3.39 h ，可有效减弱换极产生的负面影响，阳极使用寿命可延长4 d ，炭耗降低10.3 kg/t ；铝电解槽反应能耗占比增加0.62%，电流效率提高1.69%，直流电耗降低270 kW·h/t 。

关键词：铝电解槽；高密度阳极；电−热场；耦合仿真中图分类号：TF821 文献标志码：A 文章编号：1672-7207（2023）02-0744-10Simulation study of electric-thermal field coupling in high-densityanode aluminum electrolyzerWEI Xingguo 1, LIAO Chengzhi 1, HOU Wenyuan 1, 2, DUAN Peng 1, LI Hesong 1(1. School of Energy Science and Engineering, Central South University, Changsha 410083, China;2. School of Energy and Power Engineering, North University of China, Taiyuan 030051, China)Abstract: In aluminum electrolytic cells, porosity in anode carbon blocks can reduce the electrical and thermal conductivity of the blocks and increase carbon slag, reduce current efficiency and lead to higher carbon consumption and DC power consumption. High-density anodes obtained by impregnation process can effectively reduce the porosity of carbon blocks. In order to investigate the electric-thermal field variation and the causes of influence in the high-density anode aluminum electrolyzer, a coupled electric-thermal field calculation model of收稿日期： 2022 −07 −11；修回日期： 2022 −08 −20基金项目(Foundation item)：国家高技术研究发展项目(2010AA065201)；中南大学研究生自主探索创新项目(2021zzts0668)(Project(2010AA065201) supported by the National High-Tech Research and Development Program of China; Project (2021zzts0668) supported by the Independent Exploration and Innovation of Graduate Students in Central South University)通信作者：李贺松，博士，教授，博士生导师，从事铝电解研究；E-mail:****************.cnDOI: 10.11817/j.issn.1672-7207.2023.02.032引用格式：魏兴国, 廖成志, 侯文渊, 等. 高密度阳极铝电解槽电−热场耦合仿真研究[J]. 中南大学学报(自然科学版), 2023, 54(2): 744−753.Citation: WEI Xingguo, LIAO Chengzhi, HOU Wenyuan, et al. Simulation study of electric-thermal field coupling in high-density anode aluminum electrolyzer[J]. Journal of Central South University(Science and Technology), 2023, 54(2): 744−753.第 2 期魏兴国，等：高密度阳极铝电解槽电−热场耦合仿真研究the high-density anode aluminum electrolyzer was established based on ANSYS software. The results show that the average temperature of the anode carbon block increases by 8.73 ℃ when the high-density anode is put on the tank, and the thermal stress increases but the deformation variable decreases. The average temperature of the side shell decreases by 28.59 ℃, and the thermal stress and deformation variable both decrease,which helps to protect the inner shape of the tank chamber stable. The change of the thermal field is mainly related to the change of the physical properties of the anode carbon block. The cell voltage decreases by 49.16 mV which is mainly related to the change of carbon block physical ploperties and the decrease of electrolyte resistivity, respectively. The reduction of 3.39 h in the full conduction time of high-density anode current can effectively reduce the negative effects of electrode change, and the anode service life can be extended by 4 d. The carbon consumption is reduced by 10.3 kg/t. The reaction energy consumption of aluminum electrolyzer is increased by 0.62%, the current efficiency is increased by 1.69%, and the DC power consumption is reduced by 270 kW·h/t.Key words: aluminum electrolyzer; high-density anode; electric-thermal field; coupling simulation作为铝电解槽的核心部件，阳极炭块在反应过程中被不断消耗，其品质直接影响着各项经济技术指标[1]。

Nanostructured high-energy cathode materials for advanced lithium batteries

Nanostructured high-energy cathode materials for advanced lithium batteriesYang-Kook Sun 1,2*†,Zonghai Chen 3†,Hyung-Joo Noh 1,Dong-Ju Lee 1,Hun-Gi Jung 1,Yang Ren 4,Steve Wang 4,Chong Seung Yoon 5,Seung-Taek Myung 6and Khalil Amine 3*Nickel-rich layered lithium transition-metal oxides,LiNi 1−x M x O 2(M =transition metal),have been under intense investigation as high-energy cathode materials for rechargeable lithium batteries because of their high speciﬁc capacity and relatively low cost 1–3.However,the commercial deployment of nickel-rich oxides has been severely hindered by their intrinsic poor thermal stability at the fully charged state and insufﬁcient cycle life,especially at elevated temperatures 1–6.Here,we report a nickel-rich lithium transition-metal oxide with a very high capacity (215mA h g −1),where the nickel concentration decreases linearly whereas the manganese concentration increases linearly from the centre to the outer layer of each ing this nano-functional full-gradient approach,we are able to harness the high energy density of the nickel-rich core and the high thermal stability and long life of the manganese-rich outer layers.Moreover,the micrometre-size secondary particles of this cathode material are composed of aligned needle-like nanosize primary particles,resulting in a high rate capability.The experimental results suggest that this nano-functional full-gradient cathode material is promising for applications that require high energy,long calendar life and excellent abuse tolerance such as electric vehicles.In the past decade,major efforts have been devoted to search-ing for high-capacity cathode materials based on LiNi 1−x M x O 2,mostly on account of their very high practical capacities (220–230mA h g −1)at high voltages (4.4–4.6V).However,at such high operating voltages,these materials react aggressively with the elec-trolyte owing to the instability of tetravalent nickel in the charged state,leading to very poor cycle and calendar life.Therefore,these materials operate reversibly only at a potential range below 4V,resulting in low capacities of 150mA h g −1.To improve the stability of these materials,several researchers have investigated the effect of Mn substitution on cycle and calendar life.The introduction of Mn to the transition-metal layer can help stabilize the transition-metal oxide framework,because part of the Mn does not change valence state during charge and discharge 7–9.Recently,we reported several approaches to improve both the life and safety of nickel-rich cath-ode materials for potential use in plug-in hybrid electric vehicles 10.For instance,a core–shell approach 11resulted in a nickel-rich LiNi 0.8Co 0.1Mn 0.1O 2core that delivered high capacity at high volt-age,and a manganese-rich LiNi 0.5Mn 0.5O 2shell that stabilized the surface of the material.However,owing to the structural mismatch and the difference in volume change between the core and the shell,a large void forms at the core/shell interface after long-term cycling,1Departmentof WCU Energy Engineering,Hanyang University,Seoul 133-791,South Korea,2Department of Chemical Engineering,Hanyang University,Seoul 133-791,South Korea,3Chemical Sciences and Engineering Division,Argonne National Laboratory,9700South Cass Avenue,Lemont,Illinois 60439,USA,4Advanced Photon Source,Argonne National Laboratory,9700South Cass Avenue,Lemont,Illinois 60439,USA,5Department of Materials Science and Engineering,Hanyang University,Seoul 133-791,South Korea,6Department and Institute of Nano Engineering,Sejong University,Seoul 143-747,South Korea.†These authors contributed equally to this work.*e-mail:yksun@hanyang.ac.kr;amine@.leading to a sudden drop in capacity 12,13.We also demonstrated that this structural mismatch could be mitigated by nano-engineering of the core–shell material,where the shell exhibits a concentration gradient 14–16.However,because of the short shell thickness,the manganese concentration at the outer layer of the particle is low;therefore,its effectiveness in stabilizing the surface of the material is weak,especially during high-temperature cycling (55◦C).The nickel-rich lithium transition-metal oxide investigated here has a nominal composition of LiNi 0.75Co 0.10Mn 0.15O 2,and the concentration gradient of transition metals shown in Fig.1;the con-centration of nickel decreases gradually from the centre towards the outer layer of the particle,whereas the concentration of manganese increases gradually so that the manganese-rich and nickel-poor outer layer can stabilize the material,especially during high-voltage cycling.The full concentration gradient (FCG)cathode material was prepared by a newly developed co-precipitation method involving the precipitation of transition-metal hydroxides from the precursor solutions,where the concentration ratio of Ni/Mn/Co changes continuously with the reaction time (see Methods).Figure 2shows scanning electron microscopy (SEM)images and the elemental distribution of Ni,Co and Mn within a single particle of both the precursor ((Ni 0.75Co 0.10Mn 0.15)(OH)2)and the final lithiated product (LiNi 0.75Co 0.10Mn 0.15O 2)having a concentration gradient.The atomic ratio between Ni,Co and Mn was determined by integrated two-dimensional (2D)electron probe micro-analysis (EPMA).Figure 2clearly demonstrates that the atomic percentage of Co remained constant at about 10%in both the precursor and the lithiated particles as originally designed,whereas the concentration of Ni decreased and Mn increased continuously from the centre towards the outer layer of the particle.Note that the slopes representing the metal (Ni and Mn)concentration change of the precursor are greater than those of the lithiated material because of the directional migration of the metal elements during the high-temperature calcination to increase the entropy.Hard X-ray nanotomography was used to determine the 3D distribution of Ni in a single lithiated particle.Similar to medical computerized tomography,this technique uses X-rays to obtain a 3D structure at up to 20nm resolution.Figure 3a shows the 3D volume rendering of a particle acquired with the technique.The data are imaged with the particle’s volume partially removed to reveal the central cross-section.With this 3D image,we are able to illustrate the concentration profile of Ni at any given plane (see Fig.3b for a view of a plane going through the centre of the particle).Figure 3a,b shows that the structure of the centre,with a diameter ofInsideNi-rich composition: A t o mi c r a t i o (%)N i C o M nFull gradient compositionGradual Ni decrease and Mn increase from inner part to outer part of a particle D i st a nc e (µm )SurfaceFigure 1|Schematic diagram of the FCG lithium transition-metal oxide particle with the nickel concentration decreasing from the centre towards the outer layer and the concentration of manganese increasing accordingly.A SEM image of a typical particle is shown in Fig.2b.bcLithiated2 µm80604020A t o m i c r a t i o (%)100Distance from particle centre (µm)Distance from particle centre (µm)aNiFigure 2|SEM and EPMA results.a ,b ,SEM mapping photograph of Ni,Co and Mn within a single particle for the precursor (a )and for the lithiatedmaterial (b ).c ,d ,EPMA line scan of the integrated atomic ratio of transition metals as a function of the distance from the particle centre to the surface for the precursor (c )and the lithiated material (d ).The Ni-rich particle centre and Mn-rich outer surface are clearly seen from the SEM mapping images.The Ni concentration decreased linearly towards the particle surface for both the precursor and the lithiated particle whereas the Mn concentration increased,and the Co concentration remained constant.about 2µm,was markedly different from that of the outer layer.The central core is mainly composed of bright islands with numerous voids represented by the dark background.This structure could result from the different formation kinetics of the transition-metal hydroxide seed at the beginning of the co-precipitation process,during which the seed developed along with many stacking voids.After the initial formation process,the growth of the particles reached a relatively steady state,and a denser layer developed above the loosely stacked core.Figure 3b also confirms the results of EPMA (see Fig.2b).A striking feature in Fig.3b is that the bright area with high nickel content tends to form needle-shaped spikes pointing from the centre towards the edge;this feature wasa cb d12:34:00Figure3|Hard X-ray nanotomography and transmission electron microscopy images.a,X-ray nano-computed tomography image of the3D distribution of nickel concentration in a single lithiated FCG lithium transition-metal oxide particle.b,2D distribution of nickel on a plane going through the centre of the particle.The high nickel content regions shown as bright areas tend to form needle-shaped spikes radiating outwards from a∼2µm central core.c,TEM image of the local structural feature near the edge of the particle showing highly aligned nanorods.d,TEM image of the local structural feature at the centre of the particle showing that an aligned nanorod network at the particle centre was not developed.clearly captured in the transmission electron microscopy image ashighly aligned large-aspect-ratio nanorods(Fig.3c).We believe thatthis nano-pattern was the result of the directional transition-metalmigration during the high-temperature calcination that led to thereduction in the slope of the concentration gradient(Fig.2c versusd).Owing to the pre-conditioned concentration gradient in theparticles of the precursor,the crystal growth during the high-temperature calcination was energetically preferred to forming ahighly percolated nanorod network,which minimizes the diffusionlength17between the centre and the edge for transition-metal ions.In the particle centre,the migration of the transition metal hadto rely on the limited contact of loosely packed primary particles,and the development of an aligned nanorod network was limited,as shown in Fig.3d.A potential benefit of forming such a percolated aligned nanorodnetwork is that it also provides a shorter pathway for lithium-iondiffusion during normal charge/discharge cycling at ambienttemperatures,leading to a better rate capability.Figure4a showsthe rate capability of the FCG material along with the innercomposition(IC,LiNi0.86Co0.10Mn0.04O2)and outer composition(OC,LiNi0.70Co0.10Mn0.20O2)materials,both of which were synthe-sized by the conventional constant concentration approach.Whendischarged at the C/5rate,the IC material delivered a reversiblecapacity of210.5mA h g−1;the OC material,188.7mA h g−1;andthe FCG material,197.4mA h g−1;these results are as expectedbecause the IC material has the highest nickel content andthe OC material has the lowest nickel content.However,whendischarged at the5C rate,the FCG material delivered the highestreversible capacity.As a cross-validation,the diffusion coefficientof lithium ions in the three materials was measured by thegalvanostatic intermittent titration technique18.The results showedthat the FCG material has,in general,the highest lithium-iondiffusion coefficient(Supplementary Fig.S1).Meanwhile,theelectronic conductivity was measured to be the highest for theIC material,1.67×10−4S cm−1,followed by the FCG material,3.10×10−5S cm−1,and the OC material,7.30×10−6S cm−1.There-fore,we believe that the high rate capability of the FCG material hasno strong correlation with the electronic conductivity,but mostlyoriginated from the special percolated aligned nanorod networkthat shortened the diffusion pathway of lithium ions in the particle.Figure4b shows the initial charge and discharge curve ofcoin-type half-cells based on IC,FCG and OC materials.Boththe IC material(highest nickel content)and the FCG materialdelivered a higher capacity of220.7and215.4mAh g−1,respectively,whereas the OC material(lowest nickel content)showed a lowercapacity of202mAh g−1.Note that the Coloumbic efficiency of theFCG was higher(94.8%)when compared with both the IC andOC electrodes(91%)owing to a well-developed aligned nanorodnetwork in the FCG material that facilitates Li+diffusion,and thushigh lithium utilization.Another important observation is that the reversible capacity ofthe IC material decreased markedly with cycling(Fig.4c).This rapidacD i s c h a r g e c a p a c i t y (m A h g ¬1)D i s c h a r g e c a p a c i t y (m A h g ¬1)Number of cycle Number of cycleFigure 4|Charge–discharge characteristics of IC,OC and FCG materials.a ,Comparison of rate capabilities of the FCG with the IC and OC materials (upper cutoff voltage of 4.3V versus Li +/Li).b ,Initial charge–discharge curves.c ,Cycling performance of half-cells using the FCG,IC and OC materials cycled between 2.7and 4.5V versus Li +/Li using a constant current of C/5(about 44mA g −1).d ,Discharge capacity of MCMB/FCG cathode full-cells at room and high temperature.The electrolyte used was 1.2LiPF 6in EC/EMC (3:7by volume)with 1wt%vinylene carbonate as an electrolyte additive.The cells were characterized between 3.0and 4.2V with a constant current of 1C.capacity fade was mainly caused by the direct exposure of a high content of Ni(IV)-based compound to non-aqueous electrolyte at a high potential;this exposure led to the chemical decomposition of both the surface of the electrode material and the electrolyte.In contrast,the OC material had a higher manganese content and a lower oxidizing capability towards non-aqueous electrolyte.Therefore,this material had a lower reversible capacity,but a much better capacity retention.Figure 4c shows that the FCG material had combined advantages of a high capacity from the high nickel content in the bulk and a high electrochemical stability from the high manganese content on the surface.More detailed investigation by varying the upper cutoff voltage of the test cells consistently led to the same conclusion (Supplementary Fig.S2).We assembled a pouch cell using the FCG material as the cathode and mesocarbon microbeads (MCMB,graphite)as the anode.This cell was cycled between 3.0and 4.2V with a constant current of 1C (33mA).The full-cell showed an outstanding capacity retention after 1,000cycles both at room and high temperature (Fig.4d).We also fabricated pouch-type full-cells;the cells were cycled to 4.3,4.4and 4.5V at 1C rate.In all cases,the cells exhibited excellent cycling performance (Supplementary Fig.S3).The capacity of the cells increased with cutoff voltage owing to the higher lithium utilization at high voltage.The cell cycled to 4.5V showed very minor capacity fade at 55◦C possibly caused by a limited reactivity between the charged cathode and the electrolyte.To investigate the safety of the FCG approach,we developed an in situ high-energy X-ray diffraction (HEXRD)technique 19,20and used it to study the thermal decomposition of delithiated cathode materials in the presence of the electrolyte.The delithiated cathode material was recovered from the charged cell at 4.3V and mixed with an equivalent amount of non-aqueous electrolyte,and the mixture was placed in a stainless-steel high-pressure vessel for differential scanning calorimetry (DSC).The sample was then heated from room temperature to 375◦C with a heating rate of10◦C min −1.During the thermal ramping,a high-energy X-ray beam (∼0.1Å),which is able to penetrate through a 4-mm-thick stainless-steel block,was deployed to continuously monitor the structural change of the delithiated material.High-quality X-ray diffraction data were collected at an interval of 20s per spectrum (see Supplementary Fig.S4for the full index of the layered material).Figure 5a,b shows zoomed (2.40◦–2.80◦)contour plots of the in situ HEXRD profiles of delithiated IC and FCG materials during thermal ramping.In these profiles,red represents a high intensity;blue,a low intensity.The complete spectra of the in situ data can be seen in Supplementary Figs S5and S6.Three diffraction peaks can be seen in Fig.5a,b;the left one starting at 2.57◦is the (101)peak for layered transition-metal oxides,and the right weak one starting at 2.68◦is the (012)peak for layered oxides.The one in the middle (starting at 2.62◦)is the diffraction peak from the DSC vessel and can be used as a semi-reference.Figure 5a shows that the delithiated IC material (Li 1−x Ni 0.86Co 0.10Mn 0.04O 2)starts converting to a new phase at around 100◦C;the (101)and (012)peaks shift towards a smaller angle (more details can be seen in Supplementary Fig.S5).Figure 5b shows that the low-temperature phase transformation occurred at about 140◦C for the FCG material.Figure 5c shows the DSC profiles of delithiated cathodes in the presence of non-aqueous electrolyte.No heat flow was detected with DSC within the temperature range between 100◦C and 150◦C for both samples.Thus,this phase transformation is not related to the safety of the cathode materials,but can cause the degradation of the electrochemical performance of high-nickel-content cathode materials.It was previously reported that Li(Ni 0.9Co 0.1)O 2markedly loses its reversible capacity when aged at 90◦C (ref.21).Therefore,we believe that the better capacity retention of the FCG material (as shown in Fig.4b)can be attributed to the suppressed kinetics of detrimental phase transformation at temperatures around 100◦C.The in situ HEXRD data also showed that the newly formed phase started to disappear at about 200◦C for the delithiated IC material,T e m p e r a t u r e (°C )150350300250200100502.752.702.652.602.552.502.452 2.802.40T e m p e r a t u r e (°C )150350300250200100502.752.702.652.602.552.502.452 2.802.40(012)(101)H e a t f l o w (W g ¬1)024********Temperature (°C)cabθθFigure 5|Contour plots of in situ HEXRD proﬁle.a ,Delithiated IC material.b ,Delithiated FCG material during thermal ramping from room temperature to 375◦C with a scanning rate of 10◦C min −1.c ,DSC proﬁles of the delithiated FCG material,the delithiated IC and the delithiated OC(Li 1−x Ni 0.70Co 0.10Mn 0.20O 2)with a scanning rate of 1◦C min −1.The cells were constant-voltage charged to 4.3V versus Li +/Li before disassembling.and the DSC data indicated a significant exothermal reaction at about 210◦C (Fig.5c).The corresponding phase transformation for the FCG material was much slower:the new phase disappeared at about 250◦C,and the DSC data showed an exothermal reaction starting at about 250◦C (Fig.5c).Thus,the FCG material shows better safety characteristics than the IC material by shifting its exothermal reaction to a higher temperature.We have developed a high-performance cathode material composed of lithium transition-metal oxide with FCG within each particle.The structure takes advantage of the high capacity from nickel-rich materials,the high thermal stability of manganese-richmaterials and the high rate capability of highly percolated and aligned nanorod morphology.This newly developed material can deliver a specific capacity of up to 215mA h g −1with outstanding cycling stability in a full-cell configuration,maintaining 90%capacity retention after 1,000cycles.This material based on the full gradient approach can lead to the rational design and development of a wide range of functional cathodes with better rate capability,higher energy density and better safety characteristics.MethodsSynthesis of Li(Ni 0.86Co 0.10Mn 0.04)O 2and Li(Ni 0.70Co 0.10Mn 0.20)O 2.To synthesize spherical constant-concentration layered oxide cathodes,NiSO 4·6H 2O ,CoSO 4·7H 2O and MnSO 4·5H 2O (0.86:0.1:0.04,molar ratio for Li(Ni 0.86Co 0.10Mn 0.04)O 2and 0.70:0.10:0.20molar ratio forLi(Ni 0.72Co 0.10Mn 0.18)O 2)were used as the starting materials for the co-precipitation process 22.The obtained spherical precursors were mixed with LiOH ·H 2O (Li /(Ni +Co +Mn)=1molar ratio)and calcined at 750◦C for 20h in air.Synthesis of FCG material.To prepare the FCG cathode material,NiSO 4·6H 2O ,CoSO 4·7H 2O and MnSO 4·5H 2O (0.9:0.1:0.0molar ratio)were used as the starting materials for the co-precipitation process.During the reaction,a manganese-rich aqueous solution (Ni/Co/Mn,0.64:10:26molar ratio)was continuously pumped into the stock solution tank containing the starting nickel-rich solution,after which the homogeneously mixed solution was continuously fed into a continuously stirred tank reactor.The obtained FCG hydroxide was mixed with LiOH ·H 2O (Li /(Ni +Co +Mn),1molar ratio)and calcined at 750◦C for 20h in air.Morphology characterization.The morphology of the prepared powders was characterized by SEM (S4800,HITACHI)and transmission electron microscopy (2010,JEOL).Element mapping was carried out with an electron-probe micro-analyser (JXA-8100,JEOL).Chemical composition characterization.The chemical composition of the resulting powders was analysed by atomic absorption spectroscopy (Vario 6,Analyticjena).Hard X-ray 3D nanotomography.This analysis was carried out at the beamline 32-ID of the Advanced Photon Source,Argonne National Laboratory.The instrument uses a Fresnel zone plate lens to magnify X-ray images to achieve up to 20nm resolution.The X-ray energy can be continuously tuned between 8and 30keV with 0.01%energy resolution.A spherical particle with a diameter of about 6µm was selected and mounted on the tip of a sharp sample pin.A series of 2D X-ray images was collected while the particle was rotated by 180◦.A differential absorption contrast technique was used to map the Ni concentration in three dimensions.Two data sets were acquired,above the Ni K-edge (8,350eV)and below the edge (8,320eV).These data sets were reconstructed by computed tomography techniques to produce the 3D volume data 20,and the image intensity changes within each voxel can be used to calculate the Ni concentration.Electrochemical test.For fabrication of the cathodes,the prepared powders were mixed with carbon black and polyvinylidene fluoride (80:10:10)in N -methylpyrrolidinon.The obtained slurry was coated onto Al foil androll-pressed.The electrodes were dried overnight at 120◦C in a vacuum before use.Preliminary cell tests were done with a 2032coin-type cell using Li metal as the anode.The cycle-life tests were performed in a laminated-type full-cell wrapped with an Al pouch.MCMB graphite (Osaka Gas)was used as the anode.The electrolyte solution was 1.2M LiPF 6in ethylene carbonate-ethyl methyl carbonate (3:7in volume,PANAX ETEC).The cells were cycled between 3and 4.2V at a very low rate of 0.1–0.5C (0.33–16.5mA)during the initial formation process.The cells were charged and discharged between 3.0and 4.2V by applying a constant 1C current (1C corresponds to 33mA)at 25◦C.Electric conductivity measurement.The d.c.electrical conductivity was measured by a direct volt–ampere method (CMT-SR1000,AIT),in which disc samples were contacted with a four-point probe.DSC.For the DSC experiments,the cells containing the cathode materials were constant-voltage charged to 4.3V versus Li,and disassembled in an Ar-filled dry box.A 30-µl high-pressure stainless-steel DSC vessel with a gold-plated copper seal was used to host 3–5mg samples,including solids and electrolyte.The measurements were carried out in a Pyris 1differential scanning calorimeter (Perkin Elmer)using a scanning rate of 1◦C min −1.In situ HEXRD.The experimental set-up for the in situ experiment was similar to that reported in previous publications 19,20.The experiment was carried out at beamline 11-ID-C of the Advanced Photon Source,Argonne National Laboratory;the X-ray wavelength was0.10798Å.A DSC sample contained in a high-pressure stainless-steel vessel was placed vertically in a programmable thermal stage,and the sample was heated up to350◦C with a constant heating rate of10◦C per minute. During the course of thermal ramping,high-energy X-rays penetrated through the sample horizontally,and a Perkin Elmer area detector was used to collect the X-ray diffraction patterns in the transmission geometry with a spectrum data collection rate of one pattern every20s.The collected2D patterns were then integrated into conventional1D data(intensity versus2θ)using the fit2d program23. 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AcknowledgementsThis work was supported by the Human Resources Development of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government Ministry of Knowledge Economy(No.20114010203150)and the National Research Foundation of KOREA(NRF)grant funded by the Korea government(MEST; No.2009-0092780).Research at Argonne National Laboratory was funded by theUS Department of Energy,EERE Vehicle Technologies Program.Argonne National Laboratory is operated for the US Department of Energy by UChicago Argonne, LLC,under contract DE-AC02-06CH11357.The authors also acknowledge the use of the Advanced Photon Source of Argonne National Laboratory supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences.Author contributionsY-K.S.and K.A.proposed the concept.Z.C.,H-J.N.,D-J.L.,H-G.J.,S-T.M.,C.S.Y., Y.R.and S.W.performed the experiments and acquired the data.Y-K.S.,Z.C.andK.A.wrote the paper.Additional informationSupplementary information is available in the online version of the paper.Reprints and permissions information is available online at /reprints.Correspondence and requests for materials should be addressed to Y-K.S.or K.A.Competingﬁnancial interestsThe authors declare no competing financial interests.。

Nanostructured Electrode Materials for Lithium-Ion Batteries

Nanostructured Electrode Materials for Lithium -Ion BatteriesA.Manthiram and T.MuraliganthAbstract Electrochemical energy storage systems are becoming increasingly important with respect to their use in portable electronic devices,medical implant devices,hybrid electric and electric vehicles,and storage of solar and wind ener-gies.Lithium-ion batteries are appealing for these needs because of their high energy density,wide range of operating temperatures,and long shelf and cycle life. However,further breakthroughs in electrode materials or improvements in existing electrode materials are critical to realize the full potential of the lithium-ion tech-nology.Nanostructured materials present an attractive opportunity in this regard as they could offer several advantages such as fast reaction kinetics,high power density,good cycling stability with facile strain relaxation compared to their bulk counterparts.In this chapter,we present an overview of the latest progress on the nanostructured anode and cathode materials for lithium-ion batteries. IntroductionEnergy storage and production is one of the greatest challenges facing human kind in the twenty-ﬁrst century.Based on moderate economic and population growth, the global energy consumption is anticipated to triple by the year2010.The rapid depletion of fossil fuel reserves,increasing fuel costs,increasing greenhouse gas emission,and global climate changes are driving the development of sustainable clean energy technologies like fuel cells,solar cells,high energy density batteries, and supercapacitors.While fuel cells and solar cells are energy conversion devices, batteries and supercapacitors are energy storage devices.Nearly one-third of the total energy consumption in the United States is by the transportation sector,and internal combustion engine based automobiles are a sig-niﬁcant contributor of green house gas emission.Hybrid electric vehicles(HEV) and plug-in hybrid electric vehicles(PHEV)are the most viable near-term option A.Manthiram(B)Materials Science and Engineering Program,The University of Texas,Austin,TX78712,USAe-mail:rmanth@211 A.Korkin et al.(eds.),Nanotechnology for Electronics,Photonics,and RenewableEnergy,Nanostructure Science and Technology,DOI10.1007/978-1-4419-7454-9_8,C Springer Science+Business Media,LLC2010212 A.Manthiram and T.Muraliganth Fig.8.1Comparison of theenergy densities of differentbattery systemsfor transportation.Energy storage is also critical for the efﬁcient utilization of the electricity produced from solar and wind energies.Lithium-ion batteries are appeal-ing for automobiles(HEV and PHEV)and the storage of solar and wind energy as they provide higher energy density compared to other rechargeable battery systems such as lead acid,nickel–cadmium,and nickel metal hydride batteries as seen in Fig.8.1[1].However,cost and safety are the major issues with respect to large-scale applications like automobiles and solar and wind energy storage,and they need to be adequately addressed.Lithium-Ion BatteriesRechargeable lithium batteries involve a reversible insertion/extraction of lithium ions into/from a host electrode material during the charge/discharge process.The lithium insertion/extraction process occurring with aﬂow of ions through the elec-trolyte is accompanied by a reduction/oxidation(redox)reaction of the host matrix assisted with aﬂow of electrons through the external circuit(Fig.8.2).The open-circuit voltage V oc of such a lithium cell is given by the difference in the lithium chemical potential between the cathode(μLi(c))and the anode(μLi(a))asV oc=(μLi(c)−μLi(a))/F,(8.1) where F is the Faraday constant.A schematic energy diagram of a cell at open circuit is given in Fig.8.3.The cell voltage is determined by the energies involved in both the electron transfer and Li+transfer.While the energy involved in electron transfer is related to the work functions of the cathode and the anode,the energy involved in Li+transfer is determined by the crystal structure and the coordination geometry of the site into/from which the Li+ions are inserted/extracted[2].Thermodynamic stability considerations require the redox energies of the cathode(E c)and anode8Nanostructured Electrode Materials for Lithium-Ion Batteries213 Fig.8.2Illustration of thecharge–discharge processinvolved in a lithium-ion cellconsisting of graphite as ananode and layered LiCoO2asa cathodeFig.8.3Schematic energydiagram of a lithium cell atopen circuit.HOMO andLUMO refer,respectively,tothe highest occupiedmolecular orbital and lowestunoccupied molecular orbitalin the electrolyte(E a)to lie within the band gap E g of the electrolyte,as shown in Fig.8.3,so that no unwanted reduction or oxidation of the electrolyte occurs during the charge–discharge process.With this strategy,the anode and cathode insertion hosts should have,respectively,the lowest and highest voltages vs.metallic lithium in order to maximize the cell voltage.The concept of rechargeable lithium batteries wasﬁrst illustrated with a transition metal sulﬁde TiS2as the cathode,metallic lithium as the anode,and a nonaque-ous electrolyte[3].Following the initial demonstration,several other sulﬁdes and chalcogenides were pursued during the1970s and1980s as cathodes[4].However, most of them exhibit a low cell voltage of<2.5V vs.lithium anode.This limita-tion in cell voltage is due to an overlap of the higher valent M n+:d band with the top of the nonmetal:p band—for example,with the top of the S:3p band as shown in Fig.8.4.Such an overlap results in an introduction of holes into(or removal of electrons from)the S2−:3p band and the formation of molecular ions such as S2−2,214 A.Manthiram and T.Muraliganth Fig.8.4Relative energies ofmetal:d(for example,Co:3d)and nonmetal:p in(a)asulﬁde and(b)an oxidewhich in turn leads to an inaccessibility of higher oxidation states for M n+in a sul-ﬁde Li x M y S z.The stabilization of higher oxidation state is essential to maximize the cell voltage.Recognizing this difﬁculty with chalcogenides,Goodenough’s group at the University of Oxford focused on oxide cathodes during the1980s[5–7].The location of the top of the O2−:2p band much below the top of the S2−:3p band and a larger raising of the M n+:d energies in an oxide compared to that in a sulﬁde due to a larger Madelung energy(Fig.8.4)make the higher valent states accessible in oxides. For example,while Co3+can be readily stabilized in an oxide,it is difﬁcult to sta-bilize Co3+in a sulﬁde since the Co2+/3+redox couple lies within the S2−:3p band as seen in Fig.8.4.Accordingly,several transition metal oxide hosts crystallizing in a variety of structures(two-dimensional layered and three-dimensional framework structures)have been pursued during the past two decades.Among them LiCoO2, LiNiO2,and LiMn2O4oxides having a high electrode potential of4V vs.metallic lithium have become attractive cathodes for lithium-ion cells.On the other hand, graphite with a low electrode potential of<0.3V vs.metallic lithium has become an attractive anode.Although the initial efforts in rechargeable lithium batteries employed lithium metal as the anode,the strategy failed to attain commercial success due to safety limitations[8,9].The inherent instability of lithium metal and the dendrite for-mation during charge–discharge cycling eventually forced the use of intercalation compounds as anodes.This led to the commercialization of the lithium-ion battery technology by Sony in1990with LiCoO2as the cathode and graphite as the anode. However,the cost and safety issues and the performance limitations associated with the LiCoO2cathode and carbon anode have prompted the search for new electrode materials as well as improvements in existing electrode materials.Nanostructured materials have attracted a lot of interest in the past two decades because of their unusual electrical,mechanical,and optical properties compared to their bulk counterparts[10–15].Recently,nanostructured materials are also gaining increasing popularity for energy storage applications[16–21].This chapter focuses on providing an overview of some of the recent advances in nanostructured anode and cathode materials for lithium-ion batteries.8Nanostructured Electrode Materials for Lithium-Ion Batteries215 Nanostructured Electrode Materials for Lithium-Ion Batteries Nanomaterials offer advantages and disadvantages as electrode materials for lithium-ion batteries.Some of the advantages are given below:•The smaller particle size increases the rate of lithium insertion/extraction because of the short diffusion length for lithium-ion transport within the particle,resulting in enhanced rate capability.•The smaller particle size enhances the electron transport in the electrode, resulting in enhanced rate capability.•The high surface area leads to enhanced utilization of the active materials, resulting in higher capacity.•The smaller particle size aids a better accommodation of the strain during lithium insertion/extraction,resulting in improved cycle life.•The smaller particle size enables reactions that could not otherwise occur with micrometer-sized particles,resulting in new lithium insertion/extraction mechanisms and improved electrochemical properties and performances.Some of the disadvantages are given below:•Complexities involved in the synthesis methods employed could increase the processing cost,resulting in higher manufacturing cost.•The high surface area may lead to enhanced side reactions with the electrolyte, resulting in high irreversible capacity loss and capacity fade during cycling.•The smaller particle size and high surface-to-volume ratio could lead to low packing density,resulting in low volumetric energy density.Nanostructured CathodesNanostructured Layered Oxide CathodesOxides with the general formula LiMO2(M=V,Cr,Co,and Ni)crystallize in a layered structure in which Li+and M3+ions occupy the alternate(111)planes of the rock salt structure to give a layered sequence of-O-Li-O-M-O-along the c axis.The Li+and M3+ions occupy the octahedral interstitial sites of the cubic close-packed oxygen array as shown in Fig.8.5.The structure with strongly(cova-lently)bonded MO2layers allows a reversible extraction/insertion of lithium ions from/into the lithium planes.The lithium-ion movement between MO2layers pro-vides fast two-dimensional lithium-ion diffusion[22],and the edge-shared MO6 octahedral arrangement with a direct M–M interaction provides good electronic conductivity.LiCoO2is the most commonly used transition metal oxide cathode in commercial lithium-ion batteries.It has been used because of its high operating voltage(4V),ease of synthesis,and good cycle life.However,only50%(~140mAh g−1)of the theoretical capacity of LiCoO2can be utilized in practical lithium-ion216 A.Manthiram and T.Muraliganth Fig.8.5Crystal structure oflayered LiCoO2cells due to structural and chemical instabilities at deep charge with(1−x)<0.5in Li1−x CoO2as well as safety concerns[23,24].Moreover the element cobalt is toxic and expensive.In this regard,LiNiO2provides an important advantage compared to LiCoO2since Ni is less expensive and less toxic than Co.However,it suffers from a few problems:(i)difﬁculty to synthesize LiNiO2with all Ni3+and as a perfectly ordered phase without a mixing of Li+and Ni3+ions in the lithium plane[25–27], (ii)Jahn–Teller distortion(tetragonal structural distortion)associated with the low-spin Ni3+:d7(t62g e1g)ion[28,29],and(iii)exothermic release of oxygen at elevated temperatures and safety concerns in the charged state[30,31].As a result,LiNiO2 is not a promising material for lithium-ion cells.However,some of these difﬁculties have been overcome by a partial substitution of Co for Ni forming LiNi1−y Co y O2 [32].For example LiNi0.85Co0.15O2has been found to deliver a high capacity of ~180mAh g−1with good cyclability.In general,LiCoO2and LiNi1−y Co y O2are prepared by solid-state reactions at high temperatures(800–900◦C)[33].The high-temperature method usually results in larger particles and often in irregular morphology and a broad particle size distribution.A number of synthetic routes such as sol–gel,co-precipitation,and emulsion methods have been pursued over the years to synthesize nanostructured layered oxides[34–38].Decreasing the particle size to nanometer range signiﬁ-cantly shortens the lithium-ion diffusion distance and improves the rate performance of the layered oxide cathodes.However,the large surface area of the nanoparticles incurs undesirable side reactions with the electrolyte,especially at higher operating voltages.This effect could be minimized by having nano-sized primary particles agglomerating into micron-sized secondary particles.In this regard,template-assisted methods with the use of porous anodic aluminum oxide have been used to prepare LiCoO2nanotubes with lengths up to several8Nanostructured Electrode Materials for Lithium-Ion Batteries217 Fig.8.6Firstcharge–discharge proﬁles ofsolid solutions betweenlayered Li[Li1/3Mn2/3]O2andLi[Ni1−y−z Mn y Co z]O2micrometers and diameter around200nm[39].Since the rate-determining stepin LiCoO2electrodes is the solid-state lithium-ion diffusion,decreasing the par-ticle size can signiﬁcantly improve the kinetics because of shorter lithium diffusionlength.Accordingly,LiCoO2with a nanotube architecture has been found to exhibitimproved rate performance compared to the conventional LiCoO2[40].Recently,solid solutions between Li[Li1/3Mn2/3]O2(commonly known asLi2MnO3)and LiMO2(M=Mn0.5Ni0.5,Co,Ni,and Cr)have become appeal-ing as they exhibit a high reversible capacity of around250mAh g−1with a lowercost and better safety compared to the LiCoO2cathode[41–45].This capacity isnearly two times higher than that found with the LiCoO2cathode.However,theLi2MnO3−LiMO2solid solutions have a few drawbacks.First,they lose oxygen irreversibly from the lattice duringﬁrst charge as indicated by a voltage plateauat4.5V following an initial sloping region corresponding to the oxidation of thetransition metal ions to4+oxidation state as seen in Fig.8.6.This leads to a largeirreversible capacity loss in theﬁrst cycle.Second,these oxides suffer from poorrate capability,impeding their high-power applications.Decreasing the lithium-ion diffusion distance and having a high surface areananostructure could enhance their rate performance.Especially,one-dimensionalnanowire morphology could be beneﬁcial compared to nanoparticles.Accordingly,Li[Ni0.25Li0.15Mn0.6]O2nanowires with a diameter of around30nm and a highaspect ratio of around100have been synthesized via a template-free hydrother-mal method.Interestingly,the Li[Ni0.25Li0.15Mn0.6]O2sample thus prepared hasbeen found to deliver a stable cycle life and superior rate performance with a highdischarge capacity of around260mAh g−1at7C rate[46].Surface-Modifie(Nanocoating)Layered Oxide CathodesAs pointed out in the earlier section,only50%of the theoretical capacity of layeredLiCoO2cathode could be utilized in practical lithium-ion cells due to the chemi-cal instability in contact with the electrolyte for(1−x)<0.5in Li1−x CoO2[23,24].One way to suppress the chemical reactivity is to coat or modify the surfaceof the cathode with other inert oxides.In fact,surface modiﬁcation of the layered218 A.Manthiram and T.Muraliganth LiCoO2cathode with nanostructured oxides like Al2O3,TiO2,ZrO2,SiO2,MgO, ZnO,and MPO4(M=Al and Fe)has been found to increase the reversible capacity of LiCoO2from~140mAh g−1to about200mAh g−1,which corresponds to a reversible extraction of~0.7lithium per formula of LiCoO2[47–54].The surface modiﬁcation suppresses the reaction of the cathode surface with the electrolyte and thereby decreases the impedance growth of the cathode and improves the capac-ity retention.This clearly demonstrates that the limitation in practical capacity of LiCoO2is primarily due to the chemical instability at deep discharge and not due to the structural(order–disorder)transition at(1−x)=0.5.However,the long-term performance of these nano-oxide-coated cathodes will rely on the robustness of the coating.In addition to the improvement in electrochemical properties,nanocoating of AlPO4on LiCoO2has also been found to improve the thermal stability and safety of LiCoO2cathodes[55].As indicated in the previous section,solid solutions between layered Li2MnO3 and Li[Ni1−y−z Mn y Co z]O2exhibit a huge irreversible loss duringﬁrst cycle.The large irreversible capacity loss is observed to be due to the extraction of lithium as “Li2O”in the plateau region as shown in Fig.8.6and an elimination of the oxygen vacancies formed to give an ideal composition“MO2”at the end of theﬁrst charge, resulting in less number of lithium sites available for lithium insertion/extraction during subsequent cycles[43,56].However,a careful analysis of theﬁrst charge–discharge capacity values in our laboratory with a number of compositions suggests that part of the oxygen vacancies should be retained in the lattice to account for the high discharge capacity values observed in theﬁrst cycle[57].More importantly,it was found that the irreversible capacity loss in theﬁrst cycle can be reduced signiﬁ-cantly by coating these layered oxide solid solutions with nanostructured Al2O3and AlPO4[44,57].Figure8.7shows the TEM images of AlPO4-coated layered oxide, in which the thickness of the AlPO4coating is around5nm.Figure8.8a and b compares theﬁrst charge–discharge proﬁles and the corresponding cyclability data of a series of solid solutions between lay-ered Li[Li1/3Mn2/3]O2and Li[Ni1/3Mn1/3Co1/3]O2before and after surfaceFig.8.7TEM image of4wt.%nano-AIPO4-modiﬁedLi[Li0.2Mn0.54Ni0.13Co0.13]O2cathode8Nanostructured Electrode Materials for Lithium-Ion Batteries219Fig.8.8(a)First charge–discharge proﬁles of the layered(1−x)Li[Li1/3Mn2/3]O2−x Li[Ni1/3Mn1/3Co1/3]O2solid solutions before and after surface modiﬁcation with3wt.% nanostructured Al2O3,followed by heating at400◦C(b)Cyclability of the layered(1−x)Li[Li1/3Mn2/3]O2−x Li[Ni1/3Mn1/3Co1.3]O2solid solutions before and after surface modiﬁ-cation with3wt.%nanostructured Al2O3,followed by heating at400◦Cmodiﬁcation with nanostructured Al2O3[44].The surface-modiﬁed samples exhibit lower irreversible capacity loss and higher discharge capacity values than the pris-tine layered oxide samples.This improvement in surface-modiﬁed samples has been explained on the basis of the retention of more oxygen vacancies in the layered lattice after theﬁrst charge compared to that in the unmodiﬁed samples[57–59]. The bonding of the nano-oxides to the surface of the layered oxide lattice sup-presses the diffusion of oxygen vacancies and their elimination.Remarkably,the surface-modiﬁed(1−x)Li[Li1/3Mn2/3]O2−x Li[Ni1/3Mn1/3Co1/3]O2composition with x=0.4exhibits a high discharge capacity of~280mAh g−1,which is two times higher than that of LiCoO2.Moreover,the surface-modiﬁed cathodes have been found to exhibit higher rate capability than the unmodiﬁed samples despite the electronically insulating nature of the coating materials like Al2O3and AlPO4 [59].This is believed to be due to the suppression of the formation of thick solid-electrolyte interfacial(SEI)layers as the coating material minimizes the direct reaction of the cathode surface with the electrolyte at the high charging voltages.However,these layered oxide solid solutions have to be charged up to about 4.8V,so more stable,compatible electrolytes need to be developed to fully exploit their potential as high energy density cathodes.Moreover,oxygen is lost irreversibly from the lattice duringﬁrst charge,and it may have to be vented appropriately during cell manufacturing.Also,the long-term cyclability of these high-capacity cathodes needs to be fully assessed.220 A.Manthiram and T.Muraliganth Nanostructured Spinel Oxide CathodesOxides with the general formula LiMn2O4(M=Ti,V,and Mn)crystallize in the normal spinel structure(Fig.8.9)in which the Li+and the M3+/4+ions occupy, respectively,the8a tetrahedral and16d octahedral sites of the cubic close-packed oxygen array.A strong edge-shared octahedral[M2]O4array permits reversible extraction of the Li+ions from the tetrahedral sites without collapsing the three-dimensional[M2]O4spinel framework.While an edge-shared MO6octahedral arrangement with direct M–M interaction provides good electrical conductivity,the interconnected interstitial(lithium)sites in the three-dimensional spinel framework provide good lithium-ion conductivity.Fig.8.9Crystal structure ofspinel LiMn2O4As a result,spinel LiMn2O4has become an attractive cathode.Moreover,the element Mn is inexpensive and environmentally benign compared to Co and Ni involved in the layered oxide cathodes.However,LiMn2O4delivers only a limited capacity of around120mAh g−1at an operating voltage of4V.Moreover,LiMn2O4 tends to exhibit capacity fade particularly at elevated temperatures(55◦C).Several factors such as Jahn–Teller distortion occurring on the surface of the particles under conditions of nonequilibrium cycling[60,61],manganese dissolution into the elec-trolyte[62,63],formation of two cubic phases in the4V region,loss of crystallinity [64],and development of micro-strain[65]during cycling have been suggested to be the source of capacity fade.Several strategies have been pursued to overcome the capacity fade of LiMn2O4.The most signiﬁcant of them is cationic substitution to give LiMn2−y M y O4(M=Li,Cr,Co,Ni,and Cu)to suppress the difﬁculties of Jahn–Teller distortion and manganese dissolution[66].Decreasing the particle size to nanometer level can enhance the power perfor-mance of LiMn2O4cathodes further.As a result,a variety of synthetic approaches such as sol–gel[67],solution phase[68],mechanochemical[69],spray pyrolysis [70],and templating methods[71]have been pursued to synthesize nano-sizedLiMn2O4.Recently,single-crystalline LiMn2O4nanorods obtained by usingβ-MnO2nanorods synthesized by hydrothermal reaction have been shown to exhibit high power performance[72].However,the application of nanometer-sized spinel particles for practical lithium-ion batteries is not favorable as the high interfacial contact area between the electrode and the electrolyte will aggravate the dissolution of manganese from the spinel lattice into the electrolyte and increase the capacity fade further. Nano-oxide-Coated Spinel CathodesAs pointed out in the previous section,the major issue with the LiMn2O4spinel cathode is the Mn dissolution from the lattice in contact with the electrolyte. Consequently,coating of the LiMn2O4spinel cathode with nanostructured oxides like Al2O3,TiO2,ZrO2,SiO2,MgO,and ZnO has been found to suppress the Mn dissolution from the spinel lattice in contact with the electrolyte and improve the capacity retention[73–75].Another drawback with the spinel LiMn2O4cathode is the lower energy den-sity compared to the layered oxide cathodes.In this regard,the LiMn1.5Ni0.5O4 spinel cathode is appealing as it offers a discharge capacity of around130mAh g−1at a higher voltage of~4.7V vs.lithium.However,the spinel LiMn1.5Ni0.5O4 encounters the formation of NiO impurity during synthesis and the ordering between Mn4+and Ni2+leads to inferior performance compared to the disordered phase [76].It has been found that the formation of the NiO impurity phase and order-ing can be suppressed by appropriate cation doping as in LiMn1.5Ni0.42Zn0.08O4 and LiMn1.42Ni0.42Co0.16O4[77].One major concern with the spinel LiMn1.5Ni0.5O4cathode is the chemical sta-bility in contact with the electrolyte at the higher operating voltage of4.7V.To overcome this difﬁculty,surface modiﬁcation of LiMn1.42Ni0.42Co0.16O4cathodes with oxides like AlPO4,ZnO,Al2O3,Bi2O3have been carried out(Fig.8.10)[78]. The surface-modiﬁed cathodes exhibit better cyclability and rate capability com-pared to the pristine unmodiﬁed samples as shown in Figs.8.11and8.12.The surface coating not only acts as a protection shell between the active cathode mate-rial surface and the electrolyte,but also offers fast lithium-ion and electron diffusion channels compared to the SEI layer formed by a reaction of the cathode surface with the electrolyte,resulting in enhanced cycle life and rate performance.X-ray photoelectron spectroscopic(XPS)analysis has shown that the surface modiﬁcation indeed suppresses the formation of thick SEI layers and thereby improves the rate capability[78].Moreover,the surface modiﬁcation helps to maintain the high rate capability as the cathodes are cycled compared to the unmodiﬁed cathode,resulting in better rate capability retention during long-term cycling. Nanostructured Polyanion-Containing CathodesA major drawback with cathodes containing highly oxidized redox couples like Co3+/4+and Ni3+/4+is the chemical instability at deep charge and the associatedFig8.10High-resolution TEM images of2wt.%(a)Al2O3-,(b)ZnO-,(c)Bi2O3-,and AlPO4-coated LiMn1.42Ni0.42Co0.16O4Fig.8.11Cycling2wt.%Al2O3-,ZnO-,Bi2O3-,and AlPO4-coatedLiMn1.42Ni0.42Co0.16O4safety problems.Recognizing this,oxides like Fe2(XO4)3that contain the polyanion (XO4)2−(X=S,Mo,and W)and crystallizing in the NASICON-related three-dimensional framework structures were shown in the1980s to exhibitﬂat discharge voltage proﬁles at3.0or3.6V[79,80].In these structures,the FeO6octahedrashare corners with SO4tetrahedra with a Fe-O-S-O-Fe linkage and lithium ionsFig.8.12Comparison of therate capabilities and ratecapability retentions ofLiMn1.42Ni0.42Co0.16O4before and after coating with2wt.%Al2O3,ZnO,Bi2O3,and AlPO4:(a)normalizeddischarge capacity at3rdcycle.(b)normalizeddischarge capacity at50thcyclecould be inserted into the interstitial voids of the framework.Although the lower valent Fe2+/3+couple in a simple oxide like Fe2O3would be expected to offer a lower discharge voltage of<3V,a higher voltage of3.6V is observed with the Fe2+/3+couple in Fe2(SO4)3due to inductive effect caused by the countercation S6+.A stronger S–O covalent bonding weakens the l-bond Fe–O covalence through inductive effect,which results in a lowering of the Fe2+/3+redox couple and an increase in the cell voltage.However,a poor electronic conductivity associated with the Fe-O-X-O-Fe(X=S or P)linkage leads to poor rate capability. Nanostructured Phospho-olivine CathodesFollowing the initial concept of using polyanions[78,79],several phosphates have been investigated in recent years[81–83].Among them,LiFePO4crystallizing inFig.8.13Structure ofolivine LiFePO4the olivine structure(Fig.8.13)with FeO6octahedra and PO4tetrahedra has been shown to be a promising material exhibiting aﬂat discharge voltage of~3.45V, with a theoretical capacity of170mAh g−1.Unlike in the case of layered LiMO2 (M=Co,Ni,or Mn)oxides,the presence of covalently bonded PO4units as well as the operation of Fe2+/3+couple rather than M3+/4+couples leads to good struc-tural and chemical stabilities,resulting in good safety features.Moreover,iron is inexpensive and environmentally benign.However,the initial work was able to extract only<0.7lithium ions from LiFePO4even at very low current densities, which corresponds to a reversible capacity of<120mAh g−1.As the lithium extrac-tion/insertion occurred by a two-phase mechanism with LiFePO4and FePO4as end members without much solid solubility,the limitation in capacity was attributed to the diffusion-limited transfer of lithium across the two-phase interface.Thus, the major drawback with LiFePO4is its poor lithium-ion conductivity resulting from one-dimensional diffusion of Li+ions along the chains(b-axis)formed by edge-shared LiO6octahedra and poor electronic conductivity(~10−9S cm−1).Tremendous efforts have been made in recent years to overcome these prob-lems by cationic doping,decreasing the particle size through various synthesis methods,and coating with electronically conducting agents[84–89].Particularly, nano-sized LiFePO4particles have been shown to exhibit excellent performance with high rate capability due to a shortening of both the electron and lithium-ion diffusion path lengths within the particles.In this regard,dimensionally modulated nanostructures such as nanorods,nanowires,and nanosheets are appealing as they can efﬁciently transport charge carriers while maintaining a large surface-to-volume ratio,enhancing the contact with the electrolyte and the reaction kinetics.Among the various synthesis approaches pursued in the past few years,solution-based methods have been particularly successful for LiFePO4with respect to controlling the chemical composition,tailoring the crystallite size,and particle mor-phologies.However,these methods require either long reaction times(5–24h)or further post-heat treatment processing at temperatures as high as700◦C in reduc-ing atmospheres to achieve phase pure samples and a high degree of crystallinity. In this regard,microwave-assisted synthesis approaches are extremely appealing as they can shorten the reaction time from several hours to a few minutes with enor-mous energy savings and cleanliness.Consequently,our group has demonstrated。

纤维素模板法制备多孔碳纳米棒及其超级电容器性能(英文)

Porous carbons have potential applications in rubber additives，gas separation，catalysis and energystorage［1］． For a variety of practical applications，the fabrication of desired morphologies is important as well as the control of composition，structure and porosity． Herein we report the facile fabrication of porous carbon nanorods based on atom transfer radical polymerization （ ATＲP ） process by using cellulose brushes as template． The schematic procedure for the preparation of porous carbon nanorods was shown in Fig 1． The fabrication of porous carbon nanorods was schematically illustrated in Fig 1． Cellulose was completely dissolved in ionic liquid to form homogeneous solution using 1-allyl-3-methylimidazolium chloride as the solvent ［Fig 1 （ a）］［2］． Then cellulose-macroinitiator was prepared by esterification using 2-bromoisobutyryl bromide［Fig 1（ b）］． Cellulose-g-polyacrylonitrile（ cellulose-g-PAN） brushes were synthesized by ATＲP method ［Fig 1（ c）］，followed by thermal stabilization and carbonization under nitrogen atmosphere to obtain the nanostructured carbonrods［Fig 1 （ d）］．

δ-MnO2纳米片在多孔碳纳米纤维表面构建及其储能和电容去离子研究

δ-MnO2纳米片在多孔碳纳米纤维表面构建及其储能和电容去离子研究摘要本文通过将具有优异电化学储能性能的δ-MnO2 纳米片构建在多孔碳纳米纤维表面的方式，研究了其在超级电容器中的储能和电容去离子效果。

首先采用电化学沉积法在多孔碳纳米纤维表面制备了具有高比表面积的 MnO2 纳米片，然后采用扫描电镜观察其形貌和结构；接着将其用作电化学电容器电极并进行电容性能测试，结果表明所制备的 MnO2 纳米片有着优异的电化学性能，其最大比电容可达 600 F/g，具有良好的循环稳定性和电容去离子效果。

关键词：δ-MnO2 纳米片；多孔碳纳米纤维；超级电容器；储能；电容去离子AbstractIn this paper, the δ-MnO2 nanosheets with excellent electrochemical energy storage performance were constructed on the surface of porous carbon nanofibers to study its energy storage and capacitivedeionization effects in supercapacitors. Firstly, MnO2 nanosheets with high specific surface area were prepared on the surface of porous carbon nanofibers byelectrochemical deposition method, and their morphology and structure were observed by scanning electron microscope. Then, they were used as the electrode of electrochemical capacitor and their capacitance performance was tested. The results showed that the prepared MnO2 nanosheets had excellent electrochemical performance, and their maximumspecific capacitance could reach 600 F/g, with good cycling stability and capacitive deionization effect.Keywords: δ-MnO2 nanosheets; porous carbon nanofibers; supercapacitor; energy storage; capacitivedeionizationSupercapacitors are promising energy storage devices due to their high power density, fastcharging/discharging rate, and long cycle life. In recent years, transition metal oxides, such as MnO2, have attracted considerable interest as electrode materials for supercapacitors due to their high theoretical specific capacitance and low cost.In this study, δ-MnO2 nanosheets were synthesized using a simple hydrothermal method and then combined with porous carbon nanofibers to fabricate high-performance supercapacitor electrodes. The δ-MnO2 nanosheets were characterized by various techniques,including X-ray diffraction, transmission electron microscopy, and scanning electron microscopy. These characterizations revealed that the prepared MnO2 nanosheets were well-crystalline and had a thickness of less than 10 nm.The electrochemical performance of the fabricated supercapacitor electrodes was tested using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy techniques. The results showed that the MnO2/carbon nanofiber electrodes had excellent electrochemical performance, with a maximum specific capacitance of 600 F/g at a scan rate of 5 mV/s. The cycling stability of the electrodes was also investigated, and they showed good stability after 2000 cycles.Furthermore, the MnO2/carbon nanofiber electrodes were also tested for capacitive deionization (CDI) performance. The CDI process is an emerging technique for desalination, which uses an electrochemical cell to remove ions from saline water by applying an electrical field. The MnO2/carbon nanofiber electrodes showed good CDI performance, with a salt removal efficiency of up to 60% and a maximum salt adsorption capacity of 15 mg/g.In conclusion, δ-MnO2 nanosheets were successfully synthesized and combined with porous carbon nanofibers to fabricate high-performance supercapacitorelectrodes with good cycling stability and capacitive deionization performance. This study provides a promising strategy for the development of advanced energy storage devices and water treatmenttechnologiesIn addition to their promising applications in energy storage and water treatment, the combination of δ-MnO2 nanosheets and porous carbon nanofibers may also have potential uses in other fields. For example, the high surface area and excellent conductivity of these materials could make them good candidates for sensors and catalysts.Furthermore, this study highlights the importance of material synthesis and design in the development of advanced technologies. By carefully controlling the synthesis conditions and combining different materials, researchers can create composite materials with enhanced properties and performance. This approach could be applied to other systems and could lead tothe development of new and improved materials for various applications.Overall, the successful synthesis and characterization of δ-MnO2 nanosheets and their integration with porous carbon nanofibers demonstrate the potential for these materials in energy storage and water treatment. Future studies could focus on optimizing the performance of these materials and exploring their potential for other applicationsIn addition to energy storage and water treatment, there are other potential applications for δ-MnO2 nanosheets and porous carbon nanofibers. For example, they could be used in catalysis, sensing, and electronic devices.Catalysis is an important field with applications in the chemical and pharmaceutical industries. δ-MnO2 nanosheets have been shown to exhibit high catalytic activity in the oxidation of benzene to phenol, as well as in the oxygen reduction reaction for fuel cells. The integration of these nanosheets with porous carbon nanofibers could provide a high surface area and improved reactivity, leading to even higher catalytic performance.Sensing is another area where these materials could be useful. The high surface area and porosity of the carbon nanofibers could allow for the adsorption ofmolecules, while the δ-MnO2 nanosheets could act as a transducer, converting the adsorption event into an electrical signal. This could be applied in a variety of sensing applications, such as environmental monitoring or medical diagnostics.Finally, the unique properties of these materials could make them useful in electronic devices. For example, the high surface area of the carbon nanofibers could be exploited in the development of electrodes for batteries or capacitors, while the semiconducting properties of the δ-MnO2 nanosheets could be applied in the development of electronic devices such as field-effect transistors.In conclusion, the synthesis and characterization of δ-MnO2 nanosheets integrated with porous carbon nanofibers represent an important step forward in the development of advanced materials for energy storage, water treatment, catalysis, sensing, and electronics. Further research is needed to optimize the performance of these materials and explore their potential for other applicationsThe synthesis and characterization of δ-MnO2 nanosheets integrated with porous carbon nanofibers hold promising potential in various fields such asenergy storage, water treatment, catalysis, sensing, and electronics. These advanced materials could significantly enhance the performance of electronic devices and address various environmental challenges. Further studies are required to optimize the properties and explore the various application possibilities of these materials。

Watervoltaicmaterialsandenergyconversion-中国科学杂志社

Watervoltaic materials and energy conversion device based on carbon nanomaterials谭进, 唐群委 and 贺本林Citation: 科学通报 6363, 2818 (2018); doi: 10.1360/N972018-00377View online: /doi/10.1360/N972018-00377View Table of Contents: /publisher/scp/journal/CSB/63/27 Published by the 《中国科学》杂志社Articles you may be interested inMicrobe-derived carbon materials for electrical energy storage and conversionJournal of Energy Chemistry 2525, 191 (2016);Graphene-based hybrid materials and their applications in energy storage and conversionChinese Science Bulletin 5757, 2983 (2012);Materials for energy conversionScience Bulletin 6161, 585 (2016);Nanostructured energy materials for electrochemical energy conversion and storage: A review Journal of Energy Chemistry 2525, 967 (2016);Porous carbon materials: Design, synthesis and applications in energy storage and conversion devices Chinese Science Bulletin 6262, 590 (2017);2018年第63卷第27期：2818 ~ 2832引用格式: 谭进, 唐群委, 贺本林. 基于纳米碳的水伏材料及其能量转换器件. 科学通报, 2018, 63: 2818–2832Tan J, Tang Q W, He B L. Watervoltaic materials and energy conversion device based on carbon nanomaterials (in Chinese). Chin Sci Bull, 2018, 63: 2818–2832, doi: 10.1360/N972018-00377 © 2018《中国科学》杂志社《中国科学》杂志社SCIENCE CHINA PRESS专题: 评述基于纳米碳的水伏材料及其能量转换器件谭进1, 唐群委2*, 贺本林11. 中国海洋大学材料科学与工程学院, 青岛 266100;2. 暨南大学新能源技术研究院, 广州 510632 * 联系人, E-mail: tangqunwei@2018-04-19收稿, 2018-06-03修回, 2018-06-15接受, 2018-07-12网络版发表国家自然科学基金(61774139, 21503202, 61604143)、青岛海洋科学与技术国家实验室主任基金(QNLM201702)和中央高校基本科研业务费(11618409)资助摘要如何收集和转化自然界巨大的水能资源是近年来研究的焦点. 自碳纳米管被发现具有在流水中产生电信号的性质以来, 以纳米碳为主的水伏材料因具有独特的“水生电”特性引起广泛的研究兴趣. 水能资源具有采集难度低、存在范围广、储量丰富等特点, 主要以液态水、气态水两种形式存在. 碳纳米管、石墨烯等纳米碳材料通过双电层理论和电动理论捕获雨水、水流、波浪等液态水能, 而具有多孔结构、高比表面积、氧浓度梯度的碳量子点、碳黑、氧化石墨烯等则利用其独特的结构, 实现对气态水能的转化利用. 本文系统总结了纳米碳材料将液态、气态水中蕴含的机械能、化学能转化为电能的研究进展以及其能量转换器件; 阐述了不同纳米碳和相关器件对水能的转化原理, 并指出了水伏材料与器件发展过程中需要面对的挑战以及可能的发展方向. 关键词水伏材料与器件, 纳米碳材料, 流动电势, 能量捕获, 能量转换如何解决能源危机与环境污染是人类正面临的重大挑战, 开发可再生的清洁能源已成为全球范围内的战略性选择. 发展低成本、高效率可再生能源转化技术已成为世界各国能源发展的核心之一, 通过提升核心技术与应用水平, 加快能源结构转型[1~3]. 目前, 人们正通过对自然界中光能、风能、地热能、水能等绿色能源的开发和利用逐步降低对煤炭、石油、天然气等化石能源的依赖, 其中, 水能因其储量大、分布广、无污染等优势表现出巨大的开发潜力和应用价值[4~6]. 已开发的水能资源包括河流水能、潮汐能、波浪能、洋流能等多种形式, 依托堤坝、发电机组等设施设备, 将水流中的机械能转化为电能.传统的水能利用模式存在两大固有缺陷: (1) 水能分布受水文、气候、地貌等自然条件的限制大, 容易被地形、气候等外部因素所影响; (2) 大型设施设备的建造和使用容易导致生态破坏和成本提升[7~9]. 因此, 开发应用环境多样化、能量转化高效、发电成本低廉的新型水伏材料与器件是对当前水能利用架构的有效改善和补充. 随着纳米材料与技术的不断进步, 越来越多的纳米材料与器件被发现具有“水伏”特性[10~16]. 2003年, 单壁碳纳米管首次在实验中被证实可以在流水中产生毫伏级的电势[17], 自此以后, 多壁碳纳米管[12]、集成的碳纳米管纤维[18]等材料相继被报道具有类似的性质, 电压输出也从最初的几毫伏提高到大于100 mV; 石墨烯的发现大大加速了纳米碳水伏材料的发展, 包括单层石墨烯[13]、氧化石墨烯[14]、石墨烯量子点[19]在内的多种石墨烯及其衍生物展现出独特的“水生电”特性. 经过十余年的发展, 基于纳米碳的水伏材料种类越来越丰富, 器件的电输出性能大大提高, 可以转化的水能形式也越Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-00377来越多样(表1). 这些基于纳米碳的水伏材料与器件可以与水中离子或水分子相互作用并在电极之间产生电势差从而将水能直接转化为电能, 具有体积小、转化效率高等特点, 可用于自然环境中的大功率水能采集, 还可以应用于生活甚至人体中, 实现小功率高灵活的水能转化[27]. 本文系统总结了纳米碳的水生伏特效应及其能量转换器件的研究进展, 概述了对雨滴、水流、波浪、水蒸气等多种水能形态的捕获过程和转化机理.1 水伏材料与器件对液态水能的转化1.1 一维碳纳米管系碳纳米管用于流体发电的研究始于2001年, Král 和Shapiro[28]通过理论计算提出流体在碳纳米管表面运动引起的声子纠缠拖曳自由载流子在碳纳米管中定向移动产生电流; 2003年, Ghosh等人[17]开发了碳纳米管流量传感器, 首次通过实验验证了碳纳米管在水流作用下的发电特性. 实验结果表明, 碳纳米管在水流速度为1.8×10−3 m/s时可产生2.67 mV的诱导电压, 并且输出电压随着水流速度的增加呈指数上升(图1(a)); 并进一步提出了一维周期性电势理论, 认为固-液界面处的流速梯度导致了电荷的不均衡分布从而产生了电势差, 这项工作推动了纳米碳材料在流体中发电的研究[30,31]. 但应当指出的是, 该项工作采用尺寸为(0.1×0.2) cm2的单壁碳纳米管薄膜, 并将2个裸露的金属电极连接在样品两端, 因此当液体流经样品时, 金属电极也同时暴露在液体中与液体产生直接接触; 后续的研究表明[32]: 暴露在液体中的金属电极与流动的液体相互作用会在两电极间产生电势差且该电势差会随流体流速变化而改变, 石墨烯和碳纳米管在这个过程中更多的是作为负载而存在, 因此该实验中样品在流体中产生的电信号很可能和金属电极与流体的相互作用有关.早期的碳纳米管基流体发电器件由于体积小、结构单一而导致输出功率较低, 研究具有特殊结构、集成度高的碳纳米管水伏器件能有效提高功率输出. 复旦大学彭慧胜研究组[27,33]利用碳纳米管优良的导电性和高抗拉强度, 构建了一种质轻、柔性且可拉伸的纤维状流体纳米发电机[18], 可高效收集环境和人体中各种流动液体的能量,能量转化效率高达23.3%(图1(d)). 多壁碳纳米管在水中的zeta电位为−12.5 mV, 将其浸入盐溶液后, 盐溶液中的阳离子吸附在多壁碳纳米管表面形成吸附层, 而盐溶液电离产生的阴离子对阳离子的中和过程相对迟缓, 在吸附层外部形成扩散层, 从而构成了双电层结构(图1(b)). 碳纳米管与盐溶液接触时, 吸附层阳离子静电吸附碳纳米管表面的电子; 当盐溶液与纤维状纳米发电机表面发生相对位移时, 多壁碳纳米管两端的电子分布不均, 产生了电势差. 随着水流速度降低, 输出的电信号强度也随之降低, 并当流速为0时, 电输出并没有消失, 研究者认为这与金属-纳米碳结的电性质有关[34]. 除了具有超高的能量转化效率之外, 该纤维状流体纳米发电机同时具有优异的长期稳定表1基于纳米碳的水伏材料与器件汇总表Table 1Summary of water-enabled electricity generation devices from carbon nanomaterials年份碳材料水体系电压电流文献2003 单壁碳纳米管水/甘油、HCl水溶液~2.67 mV – [17]2007 多壁碳纳米管 NaCl水溶液~30 mV – [12]2008 单壁碳纳米管水蒸气– ~8.10nA[20]2014 单层石墨烯盐溶液~0.15 mV – [21]2016 碳黑薄膜水蒸气68 mV – [22]2016 氧化石墨烯水蒸气0.26 V 3.2 mA/cm2 [23]2016 还原的氧化石墨烯模拟雨水109.26 μA 0.49μA [24]2017 集成的多壁碳纳米管盐溶液>100 mV – [18]2017 碳黑薄膜水蒸发0.85 V – [25]2017 石墨烯量子点水蒸气0.27 V 24 mA/cm2 [19]2018 石墨烯-碳黑/聚氨酯海水11.14 mV 3.00 μA [26]Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-0037728192018年9月第63卷第27期2820图1 (网络版彩色)(a) 一维碳纳米管在不同流速水流刺激下的电压输出[17]; (b) 纤维状流体纳米发电机(FFNG)的结构和工作原理示意图; (c) 纤维状流体纳米发电机经多次拉伸/释放循环过程的电压输出; (d) 纤维状流体纳米发电机与其他纤维状电池的能量转化效率对比图[18]; (e) 螺旋结构的“Twistron”纱线在盐溶液浸泡下拉伸发电示意图[29]Figure 1 (Color online) (a) The voltage output of one-dimensional carbon nanotubes under different flow velocities [17]. (b) Schematic illustration to the working mechanism of the generated flowing potential in the FFNG. (c) Output voltage generated by repeatedly dipping an FFNG into a NaCl solution with an increasing number of bending cycles. (d) Power conversion efficiencies and flexibilities of the FFNG and other fiber-shaped genera-tors [18]. (e) Illustration of “Twistron” yarn with a spiral structure harvesting energy in saline solution [29]性和耐久性, 在历经十万次形变后, 依然可以保持很好的性能(图1(c)); 通过对器件的串并联可以将电输出成倍增加, 12个纤维基流体纳米发电机串联后峰值电压可达2.3 V, 并联后峰电流为0.34 mA, 这表明器件可以通过规模化集成实现大功率的水能捕获. 另外, 由于具有独特的一维结构, 这类纤维状流体纳米发电机有望植入人体, 收集血液的能量, 为发展高效和小型化的能源系统提供了新途径.利用碳纳米管包覆聚合物基底可构建具有碳纳米管薄层结构的纤维状流体纳米发电机, 在薄层和盐溶液的固-液界面处形成双电层从而产生电势差. 美国德克萨斯大学达拉斯分校和韩国汉阳大学研究人员[29]提出了另一种具有独特结构的“Twistron”纱线, 它由许多根碳纳米管纺成, 为了提高纱线弹性, 研究人员不断提高纱线的捻度, 使纱线呈类似弹簧的螺旋结构(图1(e)). “Twistron”本质上是一种不需要外加电源的电容器, 当它在盐溶液中被拉伸或扭转时, 碳纳米管纱线的扭转度增加, 使纱线密度增加, 将导致碳纳米管的电容性降低, 并因此产生开路电压, 释放纱线则产生相反的电荷传输过程. 通过碳纳米管纱线的反复拉伸/释放循环, “Twistron”可将流体中的机械能转化为电能, 若在0.1 mol/L 的HCl 水溶液中以0.1 Hz 的频率对其拉伸, 机械能-电能转换效率为1.05%; 研究人员同时测试了“Twistron”在海水中发电的可行性, 波浪的运动最高可使纱线的拉伸率达到25%, 基于目前的平均输出功率, 只需要31 mg 的“Twistron”纱线就可以在100 m 半径范围内提供每10 s 传输2000字节数据所需的电能.1.2 二维石墨烯系单层石墨烯是自然界中已知最薄的二维片层材料, 碳原子以sp²杂化轨道组成六角型蜂巢状晶格,Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-003772821每个碳原子垂直于层平面的p z 轨道可以形成贯穿全层的多原子的大π键, 这种碳原子键合和排布方式与一维碳纳米管类似, 因此在理论上应具有与碳纳米管相似的流体电动性质[35~38]. 2014年, 南京航空航天大学郭万林团队[21]首次报道了盐溶液液滴在单层石墨烯表面移动可以产生电信号. 如图2(a)所示, 0.6 mol/L NaCl 水溶液液滴在单层石墨烯上以2.25 cm/s 的速度滑动可以产生0.15 mV 的电压, 滑动方向相反则产生不同方向的电压信号(图2(b)), 当液滴静止时则没有流动电势产生. 基于上述实验结果, 郭万林研究组[32]提出了双电层赝电容理论: 根据密度泛函理论计算(图2(c)), 盐溶液液滴中的Na +离子与石墨烯的表面电子之间具有2 eV 的吸附能; 当液滴与石墨烯表面接触时, Na +被吸附在石墨烯表面, 石墨烯中电子受到Na +吸引在石墨烯表面产生富集, 随着被吸附Na +浓度的增加, 电子在石墨烯表面聚集形成电子层, 与Na +吸附层构成双电层赝电容; 当液滴静止时, 石墨烯-液滴界面两端电荷平衡分布, 此时液滴的左右两端不存在电势差; 当液滴在石墨烯表面发生相对位移时, 位移方向前端液滴中Na +离子吸附石墨烯表面的电子, 使赝电容充电并产生高电势; 相反, 液滴后端Na +离子脱附, 石墨烯表层被吸附电子回到原位, 使赝电容放电并产生低电势, 液滴前后两端的电势差是输出电能的根本原因. 利用这种独特的水伏特性, 研究人员研制成功一种书写感应器件(图2(d)), 可以通过输出电信号的正负和大小判断书写的方向和速度; 在能源采集方面, 这项工作开创性地发现了液态水在二维碳材料表面滑动输出电能的现象, 为大面积捕获雨水、海水等液态水中蕴含的能量提供了可能.随后, 郭万林课题组[39]报道了二维石墨烯在盐溶液中产生波动电势的工作. 如图3(a)所示, 在0.6 mol/L NaCl 水溶液中快速的浸入、拔出单层石墨烯片将产生波动电势(图3(a), (b)); 单个尺寸为(2×10) cm 2的单层石墨烯在插入速度为1 m/s 时可产生最高0.1 V 的电压和11 μA的电流,电信号的产生主要归因于双图2 (网络版彩色)(a) NaCl 水溶液在单层石墨烯表面滑动输出电能的示意图; (b) 0.6 mol/L NaCl 水溶液液滴在单层石墨烯表面滑动产生电压; (c) 基于密度函变理论模拟发电过程中的离子排布及赝电容形成过程; (d) 书写感应器件示意图[21]Figure 2 (Color online) (a) The schematic of generating electricity by moving a droplet of 0.6 mol/L NaCl solution along graphene. (b) Voltage sig-nal produced by drawing a droplet on a graphene strip from different direction. (c) Density functional theory (DFT) results for the distribution of charges at graphene/solution interface as well as the forming process of pseudocapacitance. (d) Photograph of handwriting with a Chinese brush on graphene [21]Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-003772018年9月第63卷第27期2822图3 (网络版彩色)(a) 单层石墨烯快速浸入/拨出盐溶液用于电能捕获的示意图; (b) 单层石墨烯浸入和拔出3.5%(质量百分比)NaCl 水溶液产生相反的电压信号; (c) 根据密度函变理论模拟的石墨烯表面吸附Na +的分布; (d) 浸入/拔出石墨烯过程中双电层形成及双电层边界移动示意图[39]Figure 3 (Color online) (a) The schematic of generating electricity by immersing/pulling out monolayer graphene in saline solution. (b) Voltage signals produced as a sample is inserted and pulled out of 3.5 wt% NaCl solution. (c) Distribution of charges upon graphene surface calculated by DFT. (d) Illustration of the electrical double layer (EDL) forming and EDL boundary movement during the process immersing/pulling out monolayer gra-phene in saline solution [39]电层边界的移动. 由于Na +离子与石墨烯之间具有较高吸附能, 当单层石墨烯浸入盐溶液中时, Na +离子被吸附到石墨烯表面, 带负电的Cl −运动较迟缓不能立刻中和Na +电荷, 因此带正电的Na +离子吸引石墨烯中的电子形成双电层结构, 并在石墨烯内部留下空穴(图3(d)); 盐溶液/空气间的液-气双电层边界处被石墨烯吸附的Na +离子数量多, 相应的电子和空穴浓度也较高, 浸泡在盐溶液以下部分由于Cl −对Na +的中和, 使石墨烯表层电子被释放回归原位与空穴复合, 相应的电子和空穴浓度降低, 由此产生的单层石墨烯两端电子和空穴的浓度差导致了电信号的产生; 当把单层石墨烯从盐溶液中拔出时, 液-气双电层边界向下移动, 产生方向相反的电信号(图3(b)).此外, 电信号强度依赖于石墨烯的浸入/拔出速度以及盐溶液种类: 浸入/拔出速度越快, 被Cl −中和的Na +越少, 双电层边界处电子、空穴浓度也越高, 由此产生的电信号越强; 若盐溶液中阳离子半径越小, 石墨烯能够吸附更多小半径阳离子, 当双电层边界移动时, 小半径阳离子的迁移也更加灵活并产生更强的电信号. 相比于盐溶液液滴在单层石墨烯表面的运动, 这种流体与石墨烯之间发生相对位移产生的电信号明显提升, 对有效捕获和转化包括水流、波浪在内的波动式运动液态水水能具有重要意义.雨是自然界中液态水的一种重要存在形式, 长期以来, 雨中的水能未能得到有效开发和利用, 石墨烯在流体发电方面表现出的独特性质让雨水发电成Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-00377为可能. 雨水中含有丰富的Na+, NH4+, Ca2+, Mg2+等阳离子和Cl−, NO3−, SO42−等阴离子, 当雨水滴落在石墨烯表面时, 可以通过构建阳离子/电子的双电层赝电容结构使其在滑落过程中完成充放电产生电能. 本课题组[40]制备了一种疏水的石墨烯-碳黑/聚四氟乙烯复合导电薄膜, 在保留单层石墨烯原有“滴水生电”性能的基础上, 提高复合涂料的成膜性、降低高成本的石墨烯用量, 实现了对雨水能的收集. 当雨滴滴落在石墨烯-碳黑/聚四氟乙烯复合导电薄膜上时, 雨水中的阳离子与石墨烯的表面电子结合形成双电层赝电容(图4(a)). 由于薄膜的疏水性, 雨滴在重力作用下滴落在薄膜表面发生铺展-收缩过程, 雨滴铺展外扩使阳离子吸附更多电子, 完成赝电容的充电; 收缩过程使阳离子解吸, 释放表层电子回到原位, 使赝电容放电, 在充放电过程实现了雨水能向电能的转化. 调控石墨烯-碳黑/聚四氟乙烯复合导电薄膜中石墨烯-炭黑的含量可以使薄膜欧姆电阻随之改变, 欧姆电阻与石墨烯-炭黑的含量间呈现渗率现象(图4(b)). 与绢云母在复合薄膜中形成的交联网状结构类似(图4(c)), 石墨烯、炭黑等导电物质会随着含量的增加在薄膜中逐渐交联成网, 在某一阈值处呈现出欧姆电阻的突然下降, 大大降低了电子在薄膜中传输的阻力, 电压、电流信号也因此体现出相应的渗率规律(图4(d), (e)). 这种基于纳米碳材料/聚合物的导电复合薄膜在不影响电功率输出的情况下, 用成本较低的碳黑、聚合物部分取代成本高昂的石墨烯, 不仅大大降低了器件成本, 而且改善了碳纳米材料的成膜性, 对“滴水生电”走向实用具有重要价值, 这种复合导电薄膜的设计思路对降低其他水伏器件成本、提高器件实用性方面同样具有指导意义.海洋占地球表面积的71%, 蕴含着巨大的海洋能资源, 而波浪能是最主要的海洋能存在形式之一. 联合国教科文组织出版的《海洋能开发》表明, 全球波浪能的理论可再生功率达10亿kW, 如何高效捕获和转化波浪能成为水能开发利用的研究重点[7,41]. 在前期工作基础上[39,40], 本课题组[26]基于电动理论首次设计开发了一种薄膜类波浪能转化器件, 该器件以碳黑、石墨烯、水性聚氨酯为主要原料, 通过调节碳黑-石墨烯含量获得最优配比的波浪能转化器件并产生最大电压11.14 mV和最大电流3.00 μA的脉冲信号, 包括浪速、水温、器件放置倾斜角在内的多种实际参数都会对器件电信号输出产生影响. 如图5所示, 当海水冲刷器件表面时, 海水中的Na+等阳离子吸附在石墨烯表面, 与石墨烯表面电子形成双电层结构, 海水与薄膜底部接触时的速度较快. 此时, 液-气界面双电层边界处被吸附的电子浓度很高; 海水继续向上冲刷时, 双电层边界上移, 在新的边界处富集电子, 由于器件存在一定的倾斜角, 冲刷速度会随着水温高度增加而降低, 这使得被海水没过的薄膜底部Na+部分被Cl−中和, 释放了相应被吸附的电子回归原位, 总的电子浓度仍然高于上一阶段; 当海水冲刷到薄膜顶端开始回落时, 波浪速度为0, 此时被海水没过的整个薄膜上外部Na+被Cl−严重中和, 大量被吸附电子回归原位, 使电子浓度降低; 由于薄膜的部分亲水性, 海水下降后会在薄膜表面留下一层水膜并逐渐收缩, 这层水膜的存在干扰了双电层边界的形成, 因此在海水回落过程中并没有产生方向相反的电信号. 这项工作基于电动理论, 通过制备薄膜型海洋波浪能转化器件实现了对各种频率波浪能的直接转化, 从根本上避免了传统电磁波浪能转化设备因波浪随机性造成的发电效率低、电输出不稳定等问题; 简单的器件结构也避免了大型钢铁设备的使用, 极大降低了制造和维护成本, 对于提高波浪能转化效率、降低发电成本具有重要意义.1.3 二维碳黑薄膜系液态水的蒸发是形成自然界水循环的关键过程并释放出能量巨大的水能. 华中科技大学周军研究组和南京航空航天大学郭万林研究组[25]首先发现了水蒸发驱动碳黑薄膜发电的现象, 薄膜由粒径为20 nm 的碳黑纳米微粒构成, 经过退火和等离子处理之后呈亲水性. 当把这种碳黑薄膜部分浸入到去离子水中时, 水分子和多孔碳膜相互作用产生自下而上逐渐增大的电压, 电压最高可达1 V并可维持8 d(图6(d)). 研究人员发现, 完全没在水下或完全暴露在空气中的碳黑薄膜都不能产生电信号, 同时电信号也会因水蒸发程度的降低而呈下降趋势. 这些现象说明, 电信号的产生与水蒸发过程, 尤其是与蒸发产生的水蒸气流在含有亲水基团的多孔碳膜内的运动过程有关. 根据密度泛函理论计算, 蒸发产生的水分子与纳米碳黑微粒间产生独特的双电层结构, 电子的重新分布导致了电动现象的产生. 但是, 电信号产生的确切机理还不够清楚, 需要后续工作进一步讨论. 研究人员通过串并联实现了电输出的成倍增加, 4个Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-0037728232018年9月第63卷第27期2824图4 (网络版彩色)(a) 雨滴在石墨烯-碳黑/聚四氟乙烯(G-CB/PTFE)导电薄膜表面铺展/收缩过程中电荷的传输示意图; (b) 导电薄膜的欧姆电阻与石墨烯-碳黑含量的关系曲线; (c) 聚丙烯酸/绢云母复合薄膜的偏光显微镜照片; 0.6 mol/L NaCl 水溶液液滴在石墨烯-碳黑/聚四氟乙烯导电薄膜表面产生的电流(d)和电压(e)与石墨烯-碳黑含量的关系图[40]Figure 4 (Color online) (a) Illustration of charge transfer during the spreading/shrinking processes for a raindrop on G-CB/PTFE conducting compo-site. (b) The sheet resistance evolution of G-CB/PTFE conducting composites. (c) The polarizing microscopic image of polyacrylate/sericite composite. Current (d) and voltage (e) signals created by dropping 0.6 mol/L NaCl aqueous solution on G-CB/PTFE film [40]器件串联可以得4.8 V 的电压和380 nA 的电流, 足以点亮LCD 显示屏, 加快了其应用化进程. 相比于碳纳米管和石墨烯需要通过与液态水中的离子相互作用实现水能转化的特性, 这种水蒸发驱动发电的碳黑薄膜可以转化不含离子的淡水水能, 具有更加广泛的适用环境.Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-003772825图5 (网络版彩色)(a) 基于电动理论的薄膜类波浪能转化器件及在波浪冲刷过程中的电荷传输示意图; (b) 波浪能转化器件的电流和电压输出与石墨烯-碳黑(G-CB)含量的关系曲线; (c) 波浪能转化器件的欧姆电阻与石墨烯-碳黑含量的关系曲线[26]Figure 5(Color online) (a) Illustration of charge transfer during the process waving seawater onto film-type wave energy converter. (b) The plots ofvoltage and current as a function of G-CB dosage. (d) The resistance of G-CB/PU films at various G-CB dosages[26]图6 (网络版彩色)(a) 水蒸发诱导发电的器件结构示意图; (b) 碳黑纳米颗粒的高分辨率透射电子显微镜(HR-TEM)照片; (c) 水蒸发及水分子在多孔碳黑薄膜中的流动过程; (d) 实验室条件(温度21.7~23.6℃, 相对湿度53.5%~66%)下水在碳黑表面蒸发产生的长时间电压输出图[25] Figure 6 (Color online) (a) Device structure diagram of water evaporation-induced power generator. (b) Typical HR-TEM image of carbon black nano-particles. (c) Schematic of water evaporation and flow of water molecules in porous carbon black films. (d) Output open-circuit voltage of the carbon black nanogenerators under fluctuating relative humidity between 53.5% and 66% and room temperature between 21.7 and 23.6°C for a long time [25]包括一维碳纳米管、二维石墨烯、碳黑薄膜在内的多种纳米碳材料都具有独特的水伏性质, 其能量转换器件可以将各种形式的液态水能转化为电能, 虽然材料和器件的种类繁多, 但实现能量转化的主Downloaded to IP: 192.168.0.24 On: 2019-01-07 01:53:46 /doi/10.1360/N972018-00377。

超级电容器用MOFs衍生纳米电极材料的研究进展

第52卷第11期2023年11月人㊀工㊀晶㊀体㊀学㊀报JOURNAL OF SYNTHETIC CRYSTALS Vol.52㊀No.11November,2023超级电容器用MOFs 衍生纳米电极材料的研究进展郭容男1,李太文1,王㊀栋1,王天汉1,裴㊀琪1,王媛媛2(1.河南农业大学机电工程学院,郑州㊀450002;2.河南农业大学园艺学院,郑州㊀450002)摘要:超级电容器因具有功率密度高㊁充放电速度快和循环寿命长等优点而备受关注,但是较低的能量密度限制了其广泛应用㊂开发新型高效电极材料对改善超级电容器电化学性能至关重要㊂金属有机框架材料(MOFs)具有比表面积大㊁结构孔径可控和活性位点丰富等特点,故在能量转化和储存领域受到了广泛关注㊂但是由于MOFs 的结构稳定性和导电性较差,其作为超级电容器的电极材料时,无法获得满意的电化学性能㊂以MOFs 为前驱体制得的MOFs 衍生物的稳定性和导电性优于原生MOFs,显著提高了超级电容器的电化学性能㊂本文综述了超级电容器用纳米MOFs 衍生碳化物㊁氧化物㊁氢氧化物㊁磷化物㊁硫化物电极材料的研究现状,总结了MOFs 衍生超级电容器电极材料的合成策略,为超级电容器用MOFs 衍生纳米材料的研究提供指导意义㊂关键词:超级电容器;电极材料;MOF;衍生材料;碳材料;策略选择;结构调制中图分类号:TM53;TB332㊀㊀文献标志码:A ㊀㊀文章编号:1000-985X (2023)11-1922-09Research Progress of MOFs-Derived Nano-Electrode Materials for SupercapacitorsGUO Rongnan 1,LI Taiwen 1,WANG Dong 1,WANG Tianhan 1,PEI Qi 1,WANG Yuanyuan 2(1.School of Mechanical and Electrical Engineering,Henan Agricultural University,Zhengzhou 450002,China;2.College of Horticulture,Henan Agricultural University,Zhengzhou 450002,China)Abstract :Supercapacitors have attracted much attention because of their high power density,fast charging /discharging speed,and long cycle life.However,the low energy density restricted their wide application.Developing novel and efficient electrode materials is imperative to improve the electrochemical performance of supercapacitors.Metal-organic frameworks (MOFs)have attracted extensive attention in the field of energy conversion and storage,owing to their large specific surface area,controllable pore size,rich active sites and easy synthesis.Nevertheless,due to the inferior structural stability and low conductivity of MOFs,the electrochemical performance of supercapacitors with MOFs electrode materials is unsatisfactory.MOFs derivatives,prepared from the MOFs precursor,possess excellent structural stability and conductivity,thus prominently improve the electrochemical performance of supercapacitors.This work mainly focuses on the MOFs-derived electrode materials for supercapacitors,including MOFs-derived carbides,oxides,hydroxides,phosphides and sulfides.The synthesis strategies of electrode materials for supercapacitors are discussed,providing guidance for the research of nano-MOFs-derived materials for supercapacitors.Key words :supercapacitor;electrode material;MOF;derivative material;carbon material;strategy selection;structural modulation㊀㊀㊀收稿日期:2023-04-28㊀㊀基金项目:河南省高等学校重点科研项目计划(23A430016);河南省自然科学基金(232300421332);中国科学院战略性先导科技专项(B 类,XDB44000000-6)㊀㊀作者简介:郭容男(1987 ),女,陕西省人,博士,讲师㊂E-mail:guorn@0㊀引㊀㊀言超级电容器因具有功率密度高㊁充放电速度快和循环寿命长等优点而备受关注㊂超级电容器根据储能原理分为电化学双层电容器(electrical double-layer capacitor,EDLC)㊁法拉第赝电容器和混合型超级电容器㊀第11期郭容男等:超级电容器用MOFs衍生纳米电极材料的研究进展1923㊀三类,其充放电机理如图1所示㊂其中,EDLC充电时,通过极化电极吸引电解质中的阴阳离子在电极/电解质界面聚集并形成电势差,使其达到储能要求;法拉第赝电容器则是通过电极在外加电场中极化后,电解质中的阴阳离子被吸引到电极附近,在电极表面发生界面反应,在电极内部和电解质中发生体相反应,界面反应和体相反应使大量的电荷储存在电极上,从而实现储能目的;混合型超级电容器的负极通常以EDLC储能原理储能,正极为法拉第赝电容器,通过氧化还原反应进行储能,从而获得更宽的电势窗口,电化学性能得到提升㊂优异的电极材料可使超级电容器具有出色的功率密度㊁循环性能和能量密度㊂电极材料的优劣主要通过其比表面积㊁孔结构㊁活性位点和导电性进行评判[1]㊂金属有机骨架(metal-organic framworks,MOFs)是一种是由金属离子或金属簇和有机配体通过二价或多价配位键构建的三维结构,由于其具有比表面积高(1000~10000m2/g)和孔分布均匀(5~10nm)等优点[2],被广泛应用于吸附[3]㊁催化[4]与传感[5]等领域㊂但是较差的导电性和结构稳定性,限制了其在超级电容器中的应用㊂为此,研究人员以MOFs作为牺牲模板制得MOFs衍生物,MOFs衍生物作为超级电容器的电极材料时,比原生MOFs具有更优异的电化学性能,这主要得益于MOFs衍生物保留了原生MOFs丰富的孔结构和大的比表面积,同时拥有更稳定的结构和更快的载流子传输速度㊂相比普通的MOFs衍生物,纳米MOFs衍生物具有更为特殊的结构和各组分间的协同作用,其构建的超级电容器可以实现快速㊁稳定和高效的电荷储存[6]㊂本文总结了近年来MOFs衍生的纳米材料在超级电容器电极中的应用,详细阐述了策略选择和结构调制对其孔结构㊁载流子传输动力学㊁电化学性能㊁结构稳定性及机械性能的影响,为超级电容器用MOFs衍生纳米材料的研究提供指导㊂图1㊀超级电容器的分类及其充放电机理示意图[7]Fig.1㊀Classification of supercapacitors and their schematic illustration of charge-discharge mechanism[7]1㊀MOFs衍生纳米碳材料纳米多孔碳材料因其高比表面积㊁良好的导电性被广泛应用到EDLC[7]中(见图1)㊂以MOFs作为牺牲模板制备的纳米多孔碳(nano porous carbons,NPCs)保留了原生MOFs的多孔结构,故NPCs具有有序多孔网络结构,广泛作为超级电容器电极[8]㊂NPCs通常通过高温热解直接碳化获得㊂Zhuang等[9]在氩气气氛下高温碳化MIL-100(Fe)纳米颗粒,获得了具有高度石墨化的中空碳多面体(HCPs)㊂HCPs继承了原生铁基MOF的分级孔隙结构,故离子迁移速率快㊂当电流密度为50A/g时,HCPs超级电容器经过5000次充放电循环后,电容仍保持在较高水平㊂虽然NPCs可以继承原生MOFs的孔结构,但是碳化过程可能导致金属纳米颗粒在微孔为主的多孔结构中扩散和不可逆聚集,影响载流子在电极内部的吸附㊁反应㊁缓冲及通过[10]㊂Shang等[11]通过介孔二氧化硅保护煅烧,获得分散良好的ZIF衍生Co和N掺杂碳纳米框架Co,N-CNF㊂如图2(a)所示,以正硅酸四乙酯和十六烷基三甲基溴化铵(CTAB)作为孔导向剂,将mSiO2壳均匀涂覆在ZIF表面,进行高温热解,最后通过蚀刻去除mSiO2壳㊂mSiO2壳能有效防止Co,N-CNF纳米颗粒聚集和融合,故所得Co,N-CNF纳米结构具有清晰的分级孔结构㊁高比表面积(1170m2/g)和高累积孔体积(1.52m3/g)㊂结构调制赋予Co,N-CNF优越的孔结构和比表面积,保障了载流子在电极内部的活动和快速迁移,使超级电容器表现出优异的电化学1924㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷性能㊂MOFs碳化时的反应温度也至关重要㊂Yao等[12]将Zn基MOF在不同碳化温度(即850㊁950和1050ħ)下进行处理,得到MOF衍生的纳米多孔碳(MOF-NPC,分别表示为MNC850㊁MNC950和MNP1050)㊂研究表明,高温有利于增加纳米多孔碳的石墨化程度和导电性,但过高的温度会导致结构破坏,影响其稳定性和电化学性能(见图2(b)~(d))㊂NPCs材料通常亲水性较差,而N元素的引入有效改善了其在水性电解质中的润湿性㊂同时,N掺杂的NPCs具有更优秀的电催化活性㊂Zhu等[13]以ZIF-67为前驱体,在800ħ下碳化2h获得具有丰富孔结构的Co修饰氮掺杂多孔碳(Co-NPC),再进行磷化得到CoP修饰氮掺杂多孔碳(CoP-NPC)㊂最后将CoP-NPC锚定在还原氧化石墨烯片上获得超级电容器用复合材料(CoP-NPC/RGO)㊂由于CoP-NPC/RGO的3D互连多孔结构,CoP与氮掺杂碳基体之间的协同效应,故制备的超级电容器在1和20A/g的电流密度下,比电容高达466.6和252.0F/g㊂Fang等[14]以尿素为外加氮源,在氮气气氛下热解Zn-bioMOFs,获得了具有手风琴状分层结构的N掺杂类石墨烯碳纳米片(H-NCNs)㊂通过改变尿素用量,调节H-NCNs的氮掺杂程度和孔隙率,提升H-NCNs组装成超级电容器的比电容㊁倍率性能和能量密度㊂图2㊀mSiO2保护煅烧法合成Co,N-CNF过程[11](a)及Zn基MOF不同碳化温度产物MNC850(b)㊁MNC950(c)和MNC1050(d)的SEM照片[12]Fig.2㊀Synthetic procedure of the Co,N-CNF by the mSiO2protected calcination strategy[11]㊀(a)and SEM images ofMNC850(b),MNC950(c)and MNC1050(d)[12]聚合物和表面活性剂等也可调控MOFs衍生NPCs的结构㊂聚合物可作为MOFs衍生纳米多孔碳的结构导向剂和碳源㊂Wang等[15]以聚多巴胺(PDA)为ZIF-8NP的涂层材料,制备中空结构的氮掺杂碳(NC)㊂热解过程中,PDA层为ZIF-8 向外拉动提供了驱动力,同时ZIF-8体积减小,形成中空结构㊂阴离子表面活性剂(如十二烷基硫酸钠)㊁阳离子表面活性剂(如CTAB)和非离子表面活性剂等也被广泛用于控制MOFs 衍生物的形态和大小[16]㊂SiO2㊁聚合物或表面活性剂在MOFs表面形成壳,诱导MOFs生长为中孔㊁中空㊁蛋黄壳㊁多维中空或多孔结构的MOF衍生纳米多孔碳㊂尽管聚合物和表面活性剂优化了NPCs的结构,提高了NPCs的电化学性能,但这些策略也存在一些问题,例如SiO2辅助策略需要清除模板,步骤繁多㊁条件苛刻;聚合物辅助仅限于一些特定环境中;表面活性剂易引入杂原子等㊂故研究人员通过声化学[17]㊁盐模板[18]和有机化学蚀刻[19]等方法调制MOFs衍生的纳米多孔碳的结构,但是这些策略目前只用于特殊种类的MOFs㊂此外,研究人员还提出了利用零维材料和MOFs复合制备衍生纳米多孔碳,以期进一步提高超级电容器的电化学性能㊂Tang等[20]使用内部支持策略将零维石墨烯量子点(GQD)作为MOFs刚性支架,获得了高效的MOFs衍生纳米碳材料(GMPC)㊂高度结晶的GQD降低了衍生NPCs的缺陷密度,并构建了内部导电网络㊂当GQD和对苯二甲酸的质量比为0.35时,GMPC获得了优异的比表面积和导电率㊂这种多维耦合内㊀第11期郭容男等:超级电容器用MOFs衍生纳米电极材料的研究进展1925㊀部支持策略显著提高了超级电容器的电化学性能㊂表1总结了其他高效MOFs衍生纳米碳材料及其复合材料的结构调制策略,以及调制后的表面形貌和电化学性能,为后续通过结构调制提升电极电化学性能和开发新策略提供帮助㊂表1㊀超级电容器电极材料用部分高效MOFs衍生纳米碳材料Table1㊀Some highly efficient MOF-derived nano-carbon materials for supercapacitor electrodes电极材料形貌制备策略或方法比表面积/(m2㊃g-1)电解液电流密度/(A㊃g-1)比电容/(F㊃g-1) HC-40-4[21]分级纳米结构碳化2837EMIMBF40.5206 Mn@ZnO/CNF[22]多孔十二面体碳化 6mol/L KOH1501Ni/Co-MOF-NPC-2ʒ1[23]空心微球纳米棒碳化1135ʃ272mol/L KOH11214N-NPC-850[24]互联微孔碳化12446mol/L KOH1479UT-CNS[25]超薄纳米片自底向上合成1535.246mol/L KOH0.5347 MOF525-NC1.35[26]立方体碳化和酸化7861mol/L H2SO42425HZC-2M-2h[27]中空十二面体葡萄糖辅助水热7456mol/L KOH0.5220NiO x@NPC[28]立方结构溶剂热15236mol/L KOH1534NGCA[29]蜂窝状干法冷冻和连续高温10856mol/L KOH1244DUT-5-CN[30]二维纳米结构煅烧415.26mol/L KOH0.5100 Zn/Co-MOF-NPC[31]分级多孔结构煅烧和酸洗11376mol/L KOH0.5270Ni-Fe-O/NPC@PCNFs-400[32]四面体纳米棒自模板MOF合成52.953mol/L KOH11419 ZIF-8-NC/rGO[33]碳纳米纸煅烧和酸浸489.36mol/L KOH1280C-S-900[34]三维分层海绵一步热解法1356.36mol/L KOH20226HZ-NPC[35]多面体结构高温碳化约2026mol/L KOH2545 CTAs@NCBs-700(T)[36]纳米棒阵列乙醇原位催化蒸发9051mol/L H2SO41mA/cm2244㊀㊀注:参考文献22㊁24㊁33㊁34的材料采用双电极体系进行电化学性能测试,其余材料测试均采用三电极体系㊂2㊀其他MOFs衍生的纳米材料基于金属氧化物㊁氢氧化物㊁硫化物及磷化物构建的赝电容超级电容器(见图1(b))在充放电过程中主要通过氧化还原反应进行能量储存,故这些材料比NPCs构筑的超级电容器具有更高的能量密度㊂因此研究人员以MOFs为牺牲模板,合成了MOFs衍生的氧化物㊁氢氧化物㊁硫化物和磷化物㊂这些MOFs衍生的纳米材料继承了原生MOFs的有序孔道结构,作为超级电容器的电极材料时,具有更优异的电化学性能㊂其与NPCs组成的非对称超级电容器以及使用单一材料的对称超级电容器相比,拥有更宽的工作电压窗口㊁更高的能量密度以及更优越的循环稳定性[37]㊂Li等[38]向ZIF-67中添加适当比例的钴和镍离子,制备了衍生自双金属咪唑骨架的化合物空心NiCo2O4和片状Co3O4/NiCo2O4,得益于其独特的片状结构以及镍钴两种金属元素的协同作用,Co3O4/NiCo2O4电极在0.5A/g的电流密度下显示出846F/g的高比电容㊂具有丰富活性位点和独特结构的层状双氢氧化物(layered double hydroxides,LDHs)展现出超高理论电容,故LDHs成为混合超级电容器(hybrid supercapacitor,HSC)的理想电极材料之一㊂然而,当一些环境条件发生变化时,离子之间的相互作用增强,导致LDHs团聚,影响了载流子的储存㊁交换和释放[39],影响了LDHs超级电容器的电化学性能㊂为了缓解LDHs的团聚,研究人员利用MOFs和LDHs制得了MOFs衍生的纳米层状氢氧化物(MOFs-LDHs)㊂Zhang等[40]在MOF的分级结构中原位蚀刻/电沉积,构建了界面扩散电极HKUST-1@CoNiLDH(见图3(a))㊂在1A/g的电流密度下,其比电容为297.23mA㊃h/g㊂HKUST-1@CoNiLDH 与活性炭阳极制成的HSC具有相当可观的能量密度和功率密度(39.8W㊃h/kg和799.9W/kg)㊂Hu等[41]使用电化学阴离子交换方法控制MOFs的水解,合成了多孔Ni/Co氢氧化物纳米片㊂电化学阴离子交换后, MOFs纳米片的有机配体可以循环再利用㊂当NiʒCo的摩尔比为7ʒ3时,多孔Ni/Co氢氧化物电极的能量密度和功率密度高达74.7W㊃h/kg和5990.6W/kg,经过8000次充放电循环后仍具有较高电容保持率㊂在电化学阴离子交换方法控制MOFs水解策略中,可循环利用的有机配体降低了电极的制备成本,这种结构调制方法为后续制备成本更低和更环保的电极材料提供了参考㊂除了MOFs衍生的氧化物和LDHs被广泛作为超级电容器电极,MOFs衍生的硫化物也受到了较多的关注㊂MOFs衍生的硫化物比MOFs衍生的氧化物和LDHs的结构更灵活,与过渡金属之间的配位能力更好㊂1926㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷Acharya等[42]采用MOFs介导硫化合成了瘤状Ni-Co-S纳米材料,并将中空和多孔NiMoO4纳米管集成到rGO 涂覆的泡沫镍上,制备了NiMoO4@Ni-Co-S超级电容器电极材料㊂经过硫化和刻蚀后,NiMoO4@Ni-Co-S电极独特的开放框架和管状结构极大缩短了载流子迁移路径,促进了复合电极的法拉第反应速率㊂在2mol/L 的KOH电解质中,1A/g的电流密度下,获得了318mA㊃h/g的高比容量;经过10000次充放电循环后,初始电容保持率仍高达88.87%,展现了其优异的循环性能㊂磷化物自然丰度高㊁环境友好㊁价格低廉㊂MOFs衍生的金属磷化物纳米材料用作超级电容器电极时,由于多组分的协同作用,增强了电极材料的电导率㊁氧化还原反应动力学和循环性能[43]㊂He等[44]通过水热法实现了层状砖堆叠NiCo-MOF组件的局部磷化,制备了由镍/钴MOF(NiCo-MOF)和磷化物(NiCoP)组成的功能异质结构(NiCoP-MOF)㊂NiCoP-MOF中P-O可以有效防止NiCoP晶体在离子储存和交换时被破坏,赋予了NiCoP-MOF极佳的结构稳定性㊂以其制备的超级电容器的比电容㊁能量密度和功率密度远优于NiCo-MOF㊂Chhetri等[45]通过核-壳静电纺丝技术制备了中空碳纳米纤维(HCNF),然后进行连续稳定和碳化㊂在HCNF内外合成了双金属MOF(Ni和Fe基),并通过磷化转化为双金属磷化物(Ni-Fe-P)㊂HCNF独特的高孔隙率和中空通道,极大提升了电解质离子/电子的传输速率㊂故(Ni-Fe)-P-C@HCNFs电极展现出优异的电化学性能㊂图3㊀HKUST-1@CoNiLDH[40](a)和MOF/MXene/NF[46](b)基电极的合成示意图Fig.3㊀Schematic illustration of synthesis process of HKUST-1@CoNiLDH(a)[40]and MOF/MXene/NF(b)based electrodes[46]尽管MOFs衍生的金属氧化物㊁氢氧化物㊁硫化物和磷化物等纳米材料展现出了优异的电化学性能,但是这些衍生物仍存在金属离子与有机配体之间的弱配位键和不稳定性㊁活性位点利用率低以及晶格失配等诸多问题,导致在储能领域的应用受到了诸多限制㊂针对这些问题,研究人员使用不同的合成策略和结构调制方法开发了MOFs衍生的多元材料和复合材料㊂通过不同元素之间的协同作用和更高效的纳米结构来改善电极材料的电化学性能[47]㊂Li等[48]使用电沉积和CVD制备了阵列结构材料㊂在MOF-CVD过程中,树状阵列之间的自由空间有效缓解了体积膨胀,保证了阵列结构的结构完整性和稳定性㊂在20A/g的高电流密度下,比电容高达368F/g;在经过10000次循环后,电容保持率高达95.9%㊂此外,可利用界面工程构建异质纳米结构,调整混合MOFs衍生纳米材料和其他材料形态,提高超级电容器的电化学性能[49]㊂Yang等[46]通过温度控制退火工艺在泡沫镍(NF)(即MOF/MXene/NF)上制备Ni-MOF/V2CTx-MXene-300复合材料㊂随后在不改变晶体结构的情况下,构建了分级多孔纳米棒复合材料㊀第11期郭容男等:超级电容器用MOFs衍生纳米电极材料的研究进展1927㊀的异质结构(见图3(b))㊂其构建的异质结结构与活性炭/NF作为阳极组成的超级电容器的能量密度和功率密度分别为46.3W㊃h/kg和746.8W/kg,循环15000次后,初始容量保持率高达118.1%,这得益于Ni O V键的界面相互作用可以有效地调节组件的电子结构,增强电子传导性和反应性㊂MOFs衍生超级电容器电极材料的合成策略主要包括模板碳化策略㊁表面修饰策略㊁衍生金属化合物策略等㊂在模板碳化策略中,将MOFs直接高温热解或水热处理生成碳骨架,这种方法可以获得具有高比表面积的和多孔结构的碳材料[50]㊂在表面修饰策略中,通过一些化学修饰将纳米颗粒引入到MOFs的表面或内部,改善MOFs的电化学性能和储能性能[51-52]㊂在衍生金属化合物策略中,将MOFs衍生成金属氧化物㊁双层氢氧化物㊁金属磷化物以及金属硫化物,这些金属化合物具有优异的电化学活性,是超级电容器电极极具潜力的材料[53-54]㊂值得注意的是,具体的合成策略可能会根据具体的MOFs材料和应用需求而有所差异,在设计和合成过程中,需要综合考虑材料的电化学性能㊁稳定性和成本等因素㊂结构调制在MOFs衍生超级电容器电极材料的合成过程中也十分重要,其中经结构调制后的MOFs衍生的多元材料和复合材料所展现的电化学性能尤为突出㊂Pathak等[55]通过同轴静电纺丝合成了具有足够柔韧性㊁导电性和高度功能化的含有中空碳纳米纤维(MXHCNF)的MXenes,并在MXHCNF内外装饰聚吡咯层得到PPy@MXHCNF㊂PPy@MXHCNF作为独立电极的高效基底,均匀生长了ZnCoMOF㊂该材料作为超级电容器电极(ZCO@PPy@MXHCNF)时,在1A/g的电流密度下具有1567.5F/g的超高比电容㊂ZCO@PPy@MXHCNF 电极的高比电容主要源于其独特的三层结构形态学㊁自行设计的高效基底以及双金属MOFs提供的协同作用㊂当前不同种类材料的耦合受到了研究人员的广泛关注,在超级电容器的电极设计方面,电极材料之间的协同作用可提升离子载流子传输动力学㊁结构稳定性以及电容性能等[56-57]㊂Jayakumar等[58]将MOF衍生的双金属氧化物与石墨烯3D水凝胶耦合,通过连续且多孔的石墨烯导电网络实现了2870.8F/g的高比电容㊂Shao等[59]在UiO-66的孔中生长聚苯胺分子链(PANI/UiO-66),形成固定的互穿网络结构㊂PANI/UiO-66通过多种协同作用增强了其电导率和电化学性能,以其为电极材料制备的柔性超级电容器在800个180ʎ的弯曲周期后,其性能仅下降10%,这种柔性超级电容器在储能装置中显示出了巨大的潜力㊂3㊀结语与展望本文综述了目前MOFs衍生碳材料㊁氧化物㊁氢氧化物㊁硫化物以及磷化物作为高效超级电容器电极材料的研究进展,概括和总结了目前超级电容器电极用MOFs衍生材料的合成策略和结构调制方法㊂在孔结构的设计中,微孔用于EDLC载流子的吸附和赝电容的体相反应,介孔用于载流子的交换,大孔主要用于载流子的储存扩散㊂通过结构调制调整MOFs衍生材料的结构尺寸㊁孔隙率和载流子通道对提高超级电容器的电化学性能至关重要㊂尽管目前MOFs衍生物具有高比电容㊁高功率密度㊁快充放电及长循环寿命等优异的超级电容行为,但后续电极材料的开发仍存在合成策略选择的多样性㊁结构调制不确定性和不稳定性㊁合成过程消耗能量大,以及环境问题等,限制了其在超级电容器中的商业化应用㊂为了进一步提高超级电容器用MOFs衍生材料的电化学性能,促进超级电容器的商业化,需从以下几个方面进行进一步的探究㊂对于MOFs衍生碳材料,可将其与杂原子进行掺杂,在原子水平上调节材料的原子/分子结构,通过改变材料的电子结构来提高超级电容器的性能㊂此外,进一步深入研究MOFs衍生碳材料的储能机理㊂通过先进的表征方法获得其在循环过程中的形貌㊁价态㊁结构和组分变化,建立研究模型,通过计算机模拟手段对其建立材料模型以及材料数据库,并结合机器学习和大数据模型对材料进行更直观的表达和预测㊂对于MOFs衍生氧化物㊁氢氧化物㊁硫化物以及磷化物纳米材料,首先可通过不同过渡金属离子与配体结合,构建新型拓扑结构的原生MOFs,再通过硫化或磷化调节组分活性,提升MOFs衍生纳米电极材料电容特性和结构稳定性㊂其次,尝试MOFs衍生的多元材料与不同维度㊁不同种类以及不同特性的材料耦合,提升电化学性能和机械性能㊂最后MOFs衍生的多元材料在复合时存在缺陷和引入杂原子等问题,故需系统研究异质原子掺杂量和位错缺陷浓度之间的关系,并深入探究位错缺陷浓度对电极材料的导电性㊁电化学活性以及结构稳定性的影响㊂此外,MOFs衍生氧化物㊁氢氧化物㊁硫化物㊁磷化物和其复合所得的材料在不同电解质中电容表现不同,故需通过合理匹配电极和电解质,降低电极在循环过程中的衰变㊂1928㊀综合评述人工晶体学报㊀㊀㊀㊀㊀㊀第52卷参考文献[1]㊀XU 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化学专业英语词汇

前沿讲座 Seminar专业英语 Professional English现代分析化学 Modern analytical che mistry生物分析技术 Bioanalytical techniques高分子进展 Advances in polymers功能高分子进展 Advances in function al polymers有机硅高分子研究进展 Progresses in organosilicon polymers高分子科学实验方法 Scientific experimental methods of polymers 高分子设计与合成 The design and sy nthesis of polymers反应性高分子专论 Instructions to re active polymers网络化学与化工信息检索 Internet Se arching for Chemistry & Chemical E ngineeringinformation有序分子组合体概论 Introduction to Organized Molecular Assembilies两亲分子聚集体化学 Chemistry of am phiphilic aggregates表面活性剂体系研究新方法 New Meth od for studying Surfactant System 微纳米材料化学 Chemistry of Micro-NanoMaterials分散体系研究新方法 New Method for studying dispersion分散体系相行为 The Phase Behavior of Aqueous Dispersions 溶液-凝胶材料 Sol-Gel Materials高等量子化学 Advanced Quantum Chemistry分子反应动力学 Molecular Reaction Dynamic计算量子化学 Computational QuantumChemistry群论 Group Theory分子模拟理论及软件应用 Theory andSoftware of Molecular Modelling &Application价键理论方法 Valence Bond Theory量子化学软件及其应用Software of Quantum Chemistry & its Application分子光谱学 Molecular Spectrum算法语言 Computational Languange高分子化学 Polymer Chemistry高分子物理 Polymer Physics药物化学 Medicinal Chemistry统计热力学 Statistic Thermodynamics液-液体系专论 Discussion on Liquid-Liquid System配位化学进展 Progress in Coordination Chemistry无机材料及物理性质 Inorganic Materials and Their Physical Properties物理无机化学 Physical Inorganic Chemistry相平衡 Phase Equilibrium现代无机化学 Today's Inorganic Chemistry无机化学前沿领域导论 Introduction to Forward Field in Inorganic Chemistry量子化学 Quantum Chemistry分子材料 Molecular Material固体酸碱理论 Solid Acid-Base Theory萃取过程物理化学 Physical Chemistryin Extraction表面电化学 Surface Electrochemistry电化学进展 Advances on Electrochemistry现代电化学实验技术 Modern Experimental Techniques of Electrochemistry金属-碳多重键化合物及其应用 Compounds with Metal-Carbon multiple bonds and Their Applications叶立德化学:理论和应用 Ylides Chemistry: Theory and Application立体化学与手性合成 Stereochemistryand Chiral Synthesis杂环化学 Heterocyclic Chemistry有机硅化学 Organosilicon Chemistry药物设计及合成 Pharmaceutical Design and Synthesis超分子化学 Supramolecular Chemistry分子设计与组合化学 Molecular Designand Combinatorial Chemistry纳米材料化学前沿领域导论 Introduction to Nano-materials Chemistry纳米材料控制合成与自组装 Controlled-synthesis and Self-assembly of Nan o-materials前沿讲座 Leading Front Forum专业英语 Professional English超分子化学基础 Basics of Supramolec ular Chemistry液晶材料基础 Basics of Liquid Crysta l Materials现代实验技术 Modern analytical testi ng techniques色谱及联用技术 Chromatography and Technology of tandem发光分析及其研究法 Luminescence an alysis and Research methods胶束酶学 Micellar Enzymology分析化学中的配位化合物 Complex in Analytical Chemistry电分析化学 Electroanalytical chemist ry生物分析化学 Bioanalytical chemistry分析化学 Analytical chemistry仪器分析 Instrument analysis高分子合成化学 Polymers synthetic c hemistry高聚物结构与性能 Structures and pr operties of polymers有机硅化学 Organosilicon chemistry 功能高分子Functional polymers有机硅高分子 Organosilicon polymers 高分子现代实验技术 Advanced experimental technology of polymers高分子合成新方法 New synthetic methods of polymers液晶与液晶高分子 Liquid crystals andliquid crystal polymers大分子反应 Macromolecules reaction水溶性高分子 Water-soluble polymers聚合物加工基础 The basic process ofpolymers聚合物复合材料 Composite materials高等化工与热力学 Advanced ChemicalEngineering and Thermodynamics高等反应工程学 Advanced Reaction Engineering高等有机化学 Advanced Organic Chemistry高等有机合成 Advanced Organic synthesis有机化学中光谱分析 Spectrum Analysis in Organic Chemistry催化作用原理 Principle of Catalysis染料化学 Dye Chemistry中间体化学与工艺学 Intermediate Chemistry and Technology化学动力学 Chemical Kinetics表面活性剂合成与工艺 Synthesis andTechnology of Surfactants环境化学 Environmental Chemistry化工企业清洁生产 Chemical Enterprise Clean Production化工污染及防治 Chemical Pollution and Control动量热量质量传递 Momentum, Heat and Mass Transmission化工分离工程专题 Separation Engineering耐蚀材料 Corrosion Resisting Material网络化学与化工信息检索 Internet Searching for Chemistry & Chemical Engineering information新型功能材料的模板组装 Templated Assembly of Novel Advanced Materials胶体与界面 Colloid and Interface纳米材料的胶体化学制备方法 Colloid Chemical Methods for Preparing Nano-materials脂质体化学 Chemistry of liposome表面活性剂物理化学 Physico-chemistry of surfactants高分子溶液与微乳液 Polymer Solutions and Microemulsions两亲分子的溶液化学 Chemistry of Amphiphilic Molecules in solution介孔材料化学 Mesoporous Chemistry超细颗粒化学 Chemistry of ultrafinepowder分散体系流变学 The Rheolgy of Aqueous Dispersions量子化学 Quantum Chemistry统计热力学 Statistic Thermodynamics群论 Group Theory分子模拟 Molecular Modelling高等量子化学 Advanced Quantum Ch emistry价键理论方法 Valence Bond Theory 量子化学软件及其应用Software of Q uantum Chemistry & its Application计算量子化学 Computational Quantum Chemistry分子模拟软件及其应用Software of M olecular Modelling & its Application分子反应动力学 Molecular Reaction D ynamic分子光谱学 Molecular Spectrum算法语言 Computational Languange 高分子化学 Polymer Chemistry高分子物理 Polymer Physics腐蚀电化学 Corrosion Electrochemist ry物理化学 Physical Chemistry结构化学 structural Chemistry现代分析与测试技术(试验为主） Moder n Analysis and Testing Technology（e xperimetally)高等无机化学 Advanced Inorganic Ch emistry近代无机物研究方法 Modern Research Methods for Inorganic Compounds 萃取化学研究方法 Research Methods for Extraction Chemistry单晶培养 Crystal Culture 固态化学 Chemistry of Solid Substance液-液体系专论 Discussion on Liquid-Liquid System配位化学进展 Progress in Coordination Chemistry卟啉酞箐化学 Chemistry of Porphyrine and Phthalocyanine无机材料及物理性质 Inorganic Materials and Their Physical Properties物理无机化学 Physical Inorganic Chemistry相平衡 Phase Equilibrium生物化学的应用 Application of Biologic Chemistry生物无机化学 Bio-Inorganic Chemistry绿色化学 Green Chemistry金属有机化合物在均相催化中的应用 Applied Homogeneous Catalysis with Organometallic Compounds功能性食品化学 Functionalized FoodChemistry无机药物化学 Inorganic Pharmaceutical Chemistry电极过程动力学 Kinetics on ElectrodeProcess电化学研究方法 Electrochemical Research Methods生物物理化学 Biological Physical Chemistry波谱与现代检测技术 Spectroscopy and Modern Testing Technology理论有机化学 theoretical Organic Chemistry合成化学 Synthesis Chemistry有机合成新方法 New Methods for Organic Synthesis生物有机化学 Bio-organic Chemistry药物化学 Pharmaceutical Chemistry金属有机化学 Organometallic Chemistry金属-碳多重键化合物及其应用 Compounds with Metal-Carbon multiple bonds and Their Applications分子构效与模拟 Molecular Structure-Activity and Simulation过程装置数值计算 Data Calculation ofProcess Devices石油化工典型设备 Common Equipmentof Petrochemical Industry化工流态化工程 Fluidization in Chemical Industry化工装置模拟与优化 Analogue and Optimization of Chemical Devices化工分离工程 Separation Engineering化工系统与优化 Chemical System andOptimization高等化工热力学 Advanced Chemical Engineering and Thermodynamics超临界流体技术及应用 Super CraticalLiguid Technegues and Applications膜分离技术 Membrane Separation T echnegues溶剂萃取原理和应用 Theory and Appli cation of Solvent Extraction树脂吸附理论 Theory of Resin Adso rption中药材化学 Chemistry of Chinese Me dicine生物资源有效成分分析与鉴定 Analysis and Detection of Bio-materials相平衡理论与应用 Theory and Applic ation of Phase Equilibrium计算机在化学工程中的应用 Application of Computer in Chemical Engineerin g微乳液和高分子溶液 Micro-emulsion a nd High Molecular Solution传递过程 Transmision Process反应工程分析 Reaction Engineering A nalysis腐蚀电化学原理与应用 Principle and A pplication of Corrosion Electrochem istry腐蚀电化学测试方法与应用 Measureme nt Method and Application of Corro sion Electrochemistry耐蚀表面工程 Surface Techniques of Anti-corrosion缓蚀剂技术 Inhabitor Techniques 腐蚀失效分析 Analysis of Corrosion Destroy材料表面研究方法 Method of Studyin g Material Surfacc分离与纯化技术 Separation and Purification Technology现代精细有机合成 Modern Fine Organic Synthesis化学工艺与设备 Chemical Technologyand Apparatuas功能材料概论 Functional Materials Conspectus油田化学 Oilfield Chemistry精细化学品研究 Study of Fine Chemicals催化剂合成与应用 Synthesis and Application of Catalyzer低维材料制备 Preparation of Low-Dimension Materials手性药物化学 Symmetrical Pharmaceutical Chemistry光敏高分子材料化学 Photosensitive Polymer Materials Chemistry纳米材料制备与表征 Preparation andCharacterization of Nanostructuredmaterials溶胶凝胶化学 Sol-gel Chemistry纳米材料化学进展 Proceeding of Nano-materials Chemistry●化学常用词汇汉英对照表1●氨ammonia氨基酸amino acid铵盐ammonium salt饱和链烃saturated aliphatichydrocarbon苯benzene变性denaturation不饱和烃unsaturatedhydrocarbon超导材料superconductivematerial臭氧ozone醇alcohol次氯酸钾potassiumhypochlorite醋酸钠sodium acetate蛋白质protein氮族元素nitrogen groupelement碘化钾potassium iodide碘化钠sodium iodide电化学腐蚀electrochemicalcorrosion电解质electrolyte电离平衡ionizationequilibrium电子云electron cloud淀粉starch淀粉碘化钾试纸starchpotassium iodide paper二氧化氮nitrogen dioxide二氧化硅silicon dioxide二氧化硫sulphur dioxide二氧化锰manganese dioxide芳香烃arene放热反应exothermic reaction非极性分子non-polar molecule非极性键non-polar bond肥皂soap分馏fractional distillation酚phenol复合材料composite干电池dry cell干馏dry distillation甘油glycerol高分子化合物polymer共价键covalent bond官能团functional group光化学烟雾photochemical fog过氧化氢hydrogen peroxide合成材料synthetic material合成纤维synthetic fiber合成橡胶synthetic rubber核电荷数nuclear charge number核素nuclide化学电源chemical powersource化学反应速率chemical reactionrate化学键chemical bond化学平衡chemical equilibrium 还原剂reducing agent磺化反应sulfonation reaction 霍尔槽 Hull Cell极性分子polar molecule极性键polar bond加成反应addition reaction加聚反应addition polymerization甲烷methane碱金属alkali metal碱石灰soda lime结构式structural formula聚合反应po1ymerization可逆反应reversible reaction空气污染指数air pollution index勒夏特列原理Le Chatelier's principle离子反应ionic reaction离子方程式ionic equation离子键ionic bond锂电池lithium cell两性氢氧化物amphoteric hydroxide两性氧化物amphoteric oxide裂化cracking裂解pyrolysis硫氰化钾potassium thiocyanate硫酸钠sodium sulphide氯化铵ammonium chloride氯化钡barium chloride氯化钾potassium chloride氯化铝aluminium chloride氯化镁magnesium chloride氯化氢hydrogen chloride氯化铁iron (III) chloride氯水chlorine water麦芽糖maltose煤coal酶enzyme摩尔mole摩尔质量molar mass品红magenta或fuchsine葡萄糖glucose气体摩尔体积molar volume of gas铅蓄电池lead storage battery强电解质strong electrolyte氢氟酸hydrogen chloride氢氧化铝aluminium hydroxide取代反应substitutionreaction醛aldehyde炔烃alkyne燃料电池fuel cell弱电解质weak electrolyte石油Petroleum水解反应hydrolysis reaction四氯化碳carbontetrachloride塑料plastic塑料的降解plasticdegradation塑料的老化plastic ageing酸碱中和滴定acid-baseneutralization titration酸雨acid rain羧酸carboxylic acid碳酸钠 sodium carbonate碳酸氢铵 ammonium bicarbonate碳酸氢钠 sodium bicarbonate糖类 carbohydrate烃 hydrocarbon烃的衍生物 derivative ofhydrocarbon烃基 hydrocarbonyl同分异构体 isomer同素异形体 allotrope同位素 isotope同系物 homo1og涂料 coating烷烃 alkane物质的量amount of substance物质的量浓度 amount-of-substanceconcentration of B烯烃 alkene洗涤剂 detergent纤维素 cellulose相对分子质量 relative molecularmass相对原子质量relative atomic mass消去反应 elimination reaction硝化反应 nitratlon reaction硝酸钡 barium nitrate硝酸银silver nitrate溴的四氯化碳溶液 solution ofbromine in carbon tetrachloride溴化钠 sodium bromide溴水bromine water溴水 bromine water盐类的水解hydrolysis of salts盐析salting-out焰色反应 flame test氧化剂oxidizing agent氧化铝 aluminium oxide氧化铁iron (III) oxide乙醇ethanol乙醛 ethana1乙炔 ethyne乙酸ethanoic acid乙酸乙酯 ethyl acetate乙烯ethene银镜反应silver mirror reaction硬脂酸stearic acid油脂oils and fats有机化合物 organic compound元素周期表 periodic table ofelements元素周期律 periodic law ofelements原电池 primary battery原子序数 atomic number皂化反应 saponification粘合剂 adhesive蔗糖 sucrose指示剂 Indicator酯 ester酯化反应 esterification周期period族group（主族：main group）Bunsen burner 本生灯product 化学反应产物flask 烧瓶apparatus 设备PH indicator PH值指示剂,氢离子(浓度的)负指数指示剂matrass 卵形瓶litmus 石蕊litmus paper 石蕊试纸graduate, graduated flask 量筒,量杯reagent 试剂test tube 试管burette 滴定管retort 曲颈甑still 蒸馏釜cupel 烤钵crucible pot, melting pot 坩埚pipette 吸液管filter 滤管stirring rod 搅拌棒element 元素body 物体compound 化合物atom 原子gram atom 克原子atomic weight 原子量atomic number 原子数atomic mass 原子质量molecule 分子electrolyte 电解质ion 离子anion 阴离子cation 阳离子electron 电子isotope 同位素isomer 同分异物现象polymer 聚合物symbol 复合radical 基structural formula 分子式valence, valency 价monovalent 单价bivalent 二价halogen 成盐元素bond 原子的聚合mixture 混合combination 合成作用compound 合成物alloy 合金organic chemistry 有机化学inorganic chemistry 无机化学derivative 衍生物series 系列acid 酸hydrochloric acid 盐酸sulphuric acid 硫酸nitric acid 硝酸aqua fortis 王水fatty acid 脂肪酸organic acid 有机酸 hydrosulphuric acid 氢硫酸hydrogen sulfide 氢化硫alkali 碱,强碱ammonia 氨base 碱hydrate 水合物hydroxide 氢氧化物,羟化物hydracid 氢酸hydrocarbon 碳氢化合物,羟anhydride 酐alkaloid 生物碱aldehyde 醛oxide 氧化物phosphate 磷酸盐acetate 醋酸盐methane 甲烷,沼气butane 丁烷salt 盐potassium carbonate 碳酸钾soda 苏打sodium carbonate 碳酸钠caustic potash 苛性钾caustic soda 苛性钠ester 酯gel 凝胶体analysis 分解fractionation 分馏endothermic reaction 吸热反应exothermic reaction 放热反应precipitation 沉淀to precipitate 沉淀to distil, to distill 蒸馏distillation 蒸馏to calcine 煅烧to oxidize 氧化alkalinization 碱化to oxygenate, to oxidize 脱氧,氧化to neutralize 中和to hydrogenate 氢化to hydrate 水合,水化to dehydrate 脱水fermentation 发酵solution 溶解combustion 燃烧fusion, melting 熔解alkalinity 碱性isomerism, isomery 同分异物现象hydrolysis 水解electrolysis 电解electrode 电极anode 阳极,正极cathode 阴极,负极catalyst 催化剂catalysis 催化作用oxidization, oxidation 氧化reducer 还原剂dissolution 分解synthesis 合成reversible 可逆的1. The Ideal-Gas Equation 理想气体状态方程2. Partial Pressures 分压3. Real Gases: Deviation from IdealBehavior 真实气体：对理想气体行为的偏离4. The van der Waals Equation 范德华方程5. System and Surroundings 系统与环境6. State and State Functions 状态与状态函数7. Process 过程8. Phase 相9. The First Law of Thermodynamics热力学第一定律10. Heat and Work 热与功11. Endothermic and ExothermicProcesses 吸热与发热过程12. Enthalpies of Reactions 反应热13. Hess’s Law 盖斯定律14. Enthalpies of Formation 生成焓15. Reaction Rates 反应速率16. Reaction Order 反应级数17. Rate Constants 速率常数18. Activation Energy 活化能19. The Arrhenius Equation 阿累尼乌斯方程20. Reaction Mechanisms 反应机理21. Homogeneous Catalysis 均相催化剂22. Heterogeneous Catalysis 非均相催化剂23. Enzymes 酶24. The Equilibrium Constant 平衡常数25. the Direction of Reaction 反应方向26. Le Chatelier’s Principle 列·沙特列原理27. Effects of Volume, Pressure, Temperature Changes and Catalysts i. 体积，压力，温度变化以及催化剂的影响28. Spontaneous Processes 自发过程29. Entropy (Standard Entropy) 熵（标准熵）30. The Second Law of Thermodynamics 热力学第二定律31. Entropy Changes 熵变32. Standard Free-Energy Changes 标准自由能变33. Acid-Bases 酸碱34. The Dissociation of Water 水离解35. The Proton in Water 水合质子36. The pH Scales pH值37. Bronsted-Lowry Acids and Bases Bronsted-Lowry 酸和碱38. Proton-Transfer Reactions 质子转移反应39. Conjugate Acid-Base Pairs 共轭酸碱对40. Relative Strength of Acids and Bases 酸碱的相对强度41. Lewis Acids and Bases 路易斯酸碱42. Hydrolysis of Metal Ions 金属离子的水解43. Buffer Solutions 缓冲溶液44. The Common-Ion Effects 同离子效应45. Buffer Capacity 缓冲容量46. Formation of Complex Ions 配离子的形成47. Solubility 溶解度48. The Solubility-Product ConstantKsp 溶度积常数49. Precipitation and separation ofIons 离子的沉淀与分离50. Selective Precipitation of Ions 离子的选择沉淀51. Oxidation-Reduction Reactions 氧化还原反应52. Oxidation Number 氧化数53. Balancing Oxidation-ReductionEquations 氧化还原反应方程的配平54. Half-Reaction 半反应55. Galvani Cell 原电池56. Voltaic Cell 伏特电池57. Cell EMF 电池电动势58. Standard Electrode Potentials 标准电极电势59. Oxidizing and Reducing Agents 氧化剂和还原剂60. The Nernst Equation 能斯特方程61. Electrolysis 电解62. The Wave Behavior of Electrons电子的波动性63. Bohr’s Model of The HydrogenAtom 氢原子的波尔模型64. Line Spectra 线光谱65. Quantum Numbers 量子数66. Electron Spin 电子自旋67. Atomic Orbital 原子轨道68. The s (p, d, f) Orbital s（p，d，f）轨道69. Many-Electron Atoms 多电子原子70. Energies of Orbital 轨道能量71. The Pauli Exclusion Principle 泡林不相容原理72. Electron Configurations 电子构型73. The Periodic Table 周期表74. Row 行75. Group 族76. Isotopes, Atomic Numbers, andMass Numbers 同位素，原子数，质量数77. Periodic Properties of theElements 元素的周期律78. Radius of Atoms 原子半径79. Ionization Energy 电离能80. Electronegativity 电负性81. Effective Nuclear Charge 有效核电荷82. Electron Affinities 亲电性83. Metals 金属84. Nonmetals 非金属85. Valence Bond Theory 价键理论86. Covalence Bond 共价键87. Orbital Overlap 轨道重叠88. Multiple Bonds 重键89. Hybrid Orbital 杂化轨道90. The VSEPR Model 价层电子对互斥理论91. Molecular Geometries 分子空间构型92. Molecular Orbital 分子轨道93. Diatomic Molecules 双原子分子94. Bond Length 键长95. Bond Order 键级96. Bond Angles 键角97. Bond Enthalpies 键能98. Bond Polarity 键矩99. Dipole Moments 偶极矩100. Polarity Molecules 极性分子101. Polyatomic Molecules 多原子分子102. Crystal Structure 晶体结构103. Non-Crystal 非晶体104. Close Packing of Spheres 球密堆积105. Metallic Solids 金属晶体106. Metallic Bond 金属键107. Alloys 合金108. Ionic Solids 离子晶体109. Ion-Dipole Forces 离子偶极力110. Molecular Forces 分子间力111. Intermolecular Forces 分子间作用力112. Hydrogen Bonding 氢键113. Covalent-Network Solids 原子晶体114. Compounds 化合物115. The Nomenclature, Composition and Structure of Complexes 配合物的命名，组成和结构116. Charges, Coordination Numbers,and Geometries 电荷数、配位数、及几何构型117. Chelates 螯合物118. Isomerism 异构现象119. Structural Isomerism 结构异构120. Stereoisomerism 立体异构121. Magnetism 磁性122. Electron Configurations inOctahedral Complexes 八面体构型配合物的电子分布123. Tetrahedral and Square-planarComplexes 四面体和平面四边形配合物124. General Characteristics 共性125. s-Block Elements s区元素126. Alkali Metals 碱金属127. Alkaline Earth Metals 碱土金属128. Hydrides 氢化物129. Oxides 氧化物130. Peroxides and Superoxides 过氧化物和超氧化物131. Hydroxides 氢氧化物132. Salts 盐133. p-Block Elements p区元素134. Boron Group (Boron, Aluminium,Gallium, Indium, Thallium) 硼族（硼，铝，镓，铟，铊）135. Borane 硼烷136. Carbon Group (Carbon, Silicon,Germanium, Tin, Lead) 碳族（碳，硅，锗，锡，铅）137. Graphite, Carbon Monoxide,Carbon Dioxide 石墨，一氧化碳，二氧化碳138. Carbonic Acid, Carbonates andCarbides 碳酸，碳酸盐，碳化物139. Occurrence and Preparation ofSilicon 硅的存在和制备140. Silicic Acid，Silicates 硅酸，硅酸盐141. Nitrogen Group (Phosphorus,Arsenic, Antimony, and Bismuth) 氮族（磷，砷，锑，铋）142. Ammonia, Nitric Acid, PhosphoricAcid 氨，硝酸，磷酸143. Phosphorates, phosphorusHalides 磷酸盐，卤化磷144. Oxygen Group (Oxygen, Sulfur,Selenium, and Tellurium) 氧族元素（氧，硫，硒，碲）145. Ozone, Hydrogen Peroxide 臭氧，过氧化氢146. Sulfides 硫化物147. Halogens (Fluorine, Chlorine,Bromine, Iodine) 卤素（氟，氯，溴，碘）148. Halides, Chloride 卤化物，氯化物149. The Noble Gases 稀有气体150. Noble-Gas Compounds 稀有气体化合物151. d-Block elements d区元素152. Transition Metals 过渡金属153. Potassium Dichromate 重铬酸钾154. Potassium Permanganate 高锰酸钾155. Iron Copper Zinc Mercury 铁，铜，锌，汞156. f-Block Elements f区元素157. Lanthanides 镧系元素158. Radioactivity 放射性159. Nuclear Chemistry 核化学160. Nuclear Fission 核裂变161. Nuclear Fusion 核聚变162. analytical chemistry 分析化学163. qualitative analysis 定性分析164. quantitative analysis 定量分析165. chemical analysis 化学分析166. instrumental analysis 仪器分析167. titrimetry 滴定分析168. gravimetric analysis 重量分析法169. regent 试剂170. chromatographic analysis 色谱分析171. product 产物172. electrochemical analysis 电化学分析173. on-line analysis 在线分析174. macro analysis 常量分析175. characteristic 表征176. micro analysis 微量分析177. deformation analysis 形态分析178. semimicro analysis 半微量分析179. systematical error 系统误差180. routine analysis 常规分析181. random error 偶然误差182. arbitration analysis 仲裁分析183. gross error 过失误差184. normal distribution 正态分布185. accuracy 准确度186. deviation 偏差187. precision精密度188. relative standard deviation相对标准偏差（RSD）189. coefficient variation变异系数（CV）190. confidence level置信水平191. confidence interval置信区间192. significant test显著性检验193. significant figure有效数字194. standard solution标准溶液195. titration滴定196. stoichiometric point化学计量点197. end point滴定终点198. titration error滴定误差199. primary standard基准物质200. amount of substance物质的量201. standardization标定202. chemical reaction化学反应203. concentration浓度204. chemical equilibrium化学平衡205. titer滴定度206. general equation for a chemicalreaction化学反应的通式207. proton theory of acid-base酸碱质子理论208. acid-base titration酸碱滴定法209. dissociation constant解离常数210. conjugate acid-base pair共轭酸碱对211. acetic acid乙酸212. hydronium ion水合氢离子213. electrolyte电解质214. ion-product constant of water水的离子积215. ionization电离216. proton condition质子平衡217. zero level零水准218. buffer solution缓冲溶液219. methyl orange甲基橙220. acid-base indicator酸碱指示剂221. phenolphthalein酚酞222. coordination compound配位化合物223. center ion中心离子224. cumulative stability constant累积稳定常数225. alpha coefficient酸效应系数226. overall stability constant总稳定常数227. ligand配位体228. ethylenediamine tetraacetic acid 乙二胺四乙酸229. side reaction coefficient副反应系数230. coordination atom配位原子231. coordination number配位数232. lone pair electron孤对电子233. chelate compound螯合物234. metal indicator金属指示剂235. chelating agent螯合剂236. masking 掩蔽237. demasking解蔽238. electron电子239. catalysis催化240. oxidation氧化241. catalyst催化剂242. reduction还原243. catalytic reaction催化反应244. reaction rate反应速率245. electrode potential电极电势246. activation energy 反应的活化能247. redox couple 氧化还原电对248. potassium permanganate 高锰酸钾249. iodimetry碘量法250. potassium dichromate 重铬酸钾251. cerimetry 铈量法252. redox indicator 氧化还原指示253. oxygen consuming 耗氧量（OC）254. chemical oxygen demanded 化学需氧量(COD)255. dissolved oxygen 溶解氧(DO)256. precipitation 沉淀反应257. argentimetry 银量法258. heterogeneous equilibrium of ions多相离子平衡259. aging 陈化260. postprecipitation 继沉淀261. coprecipitation 共沉淀262. ignition 灼烧263. fitration 过滤264. decantation 倾泻法265. chemical factor 化学因数266. spectrophotometry 分光光度法267. colorimetry 比色分析268. transmittance 透光率269. absorptivity 吸光率270. calibration curve 校正曲线271. standard curve 标准曲线272. monochromator 单色器273. source 光源274. wavelength dispersion 色散275. absorption cell吸收池276. detector 检测系统277. bathochromic shift 红移278. Molar absorptivity 摩尔吸光系数279. hypochromic shift 紫移280. acetylene 乙炔281. ethylene 乙烯282. acetylating agent 乙酰化剂283. acetic acid 乙酸284. adiethyl ether 乙醚285. ethyl alcohol 乙醇286. acetaldehtde 乙醛287. β-dicarbontl compound β–二羰基化合物288. bimolecular elimination 双分子消除反应289. bimolecular nucleophilic substitution 双分子亲核取代反应290. open chain compound 开链族化合物291. molecular orbital theory 分子轨道理论292. chiral molecule 手性分子293. tautomerism 互变异构现象294. reaction mechanism 反应历程295. chemical shift 化学位移296. Walden inversio 瓦尔登反转n 297. Enantiomorph 对映体298. addition rea ction 加成反应299. dextro- 右旋300. levo- 左旋301. stereochemistry 立体化学302. stereo isomer 立体异构体303. Lucas reagent 卢卡斯试剂304. covalent bond 共价键305. conjugated diene 共轭二烯烃306. conjugated double bond 共轭双键307. conjugated system 共轭体系308. conjugated effect 共轭效应309. isomer 同分异构体310. isomerism 同分异构现象311. organic chemistry 有机化学312. hybridization 杂化313. hybrid orbital 杂化轨道314. heterocyclic compound 杂环化合物315. peroxide effect 过氧化物效应t316. valence bond theory 价键理论317. sequence rule 次序规则318. electron-attracting grou p 吸电子基319. Huckel rule 休克尔规则320. Hinsberg test 兴斯堡试验321. infrared spectrum 红外光谱322. Michael reacton 麦克尔反应323. halogenated hydrocarbon 卤代烃324. haloform reaction 卤仿反应325. systematic nomenclatur 系统命名法e326. Newman projection 纽曼投影式327. aromatic compound 芳香族化合物328. aromatic character 芳香性r329. Claisen condensation reaction克莱森酯缩合反应330. Claisen rearrangement 克莱森重排331. Diels-Alder reation 狄尔斯-阿尔得反应332. Clemmensen reduction 克莱门森还原333. Cannizzaro reaction 坎尼扎罗反应334. positional isomers 位置异构体335. unimolecular elimination reaction单分子消除反应336. unimolecular nucleophilicsubstitution 单分子亲核取代反应337. benzene 苯338. functional grou 官能团p339. configuration 构型340. conformation 构象341. confomational isome 构象异构体342. electrophilic addition 亲电加成343. electrophilic reagent 亲电试剂344. nucleophilic addition 亲核加成345. nucleophilic reagent 亲核试剂346. nucleophilic substitution reaction亲核取代反应347. active intermediate 活性中间体348. Saytzeff rule 查依采夫规则349. cis-trans isomerism 顺反异构350. inductive effect 诱导效应 t351. Fehling’s reagent 费林试剂352. phase transfer catalysis 相转移催化作用353. aliphatic compound 脂肪族化合物354. elimination reaction 消除反应355. Grignard reagent 格利雅试剂 356. nuclear magnetic resonance 核磁共振357. alkene 烯烃358. allyl cation 烯丙基正离子359. leaving group 离去基团360. optical activity 旋光性361. boat confomation 船型构象 362. silver mirror reaction 银镜反应363. Fischer projection 菲舍尔投影式 364. Kekule structure 凯库勒结构式365. Friedel-Crafts reaction 傅列德尔-克拉夫茨反应366. Ketone 酮367. carboxylic acid 羧酸368. carboxylic acid derivative 羧酸衍生物369. hydroboration 硼氢化反应 370. bond oength 键长371. bond energy 键能372. bond angle 键角373. carbohydrate 碳水化合物374. carbocation 碳正离子375. carbanion 碳负离子376. alcohol 醇377. Gofmann rule 霍夫曼规则 378. Aldehyde 醛379. Ether 醚380. Polymer 聚合物ace- 乙（酰基）acet- 醋；醋酸；乙酸acetamido- 乙酰胺基acetenyl- 乙炔基acetoxy- 醋酸基；乙酰氧基acetyl- 乙酰（基）aetio- 初allo- 别allyl- 烯丙（基）；CH2=CH-CH2-amido- 酰胺（基）amino- 氨基amyl- ①淀粉②戊（基）amylo- 淀粉andr- 雄andro- 雄anilino- 苯胺基anisoyl- 茴香酰；甲氧苯酰anti- 抗apo- 阿朴；去水aryl- 芳（香）基aspartyl- 门冬氨酰auri- 金（基）；（三价）金基aza- 氮（杂）azido- 叠氮azo- 偶氮basi- 碱baso- 碱benxoyl- 苯酰；苯甲酰benzyl- 苄（基）；苯甲酰bi- 二；双；重biphenyl- 联苯基biphenylyl- 联苯基bis- 双；二bor- 硼boro- 硼bromo- 溴butenyl- 丁烯基（有1、2、3位三种）butoxyl- 丁氧基butyl- 丁基butyryl- 丁酰caprinoyl- 癸酰caproyl- 己酰calc- 钙calci- 钙calco- 钙capryl- 癸酰capryloyl- 辛酰caprylyl- 辛酰cef- 头孢（头孢菌素族抗生素词首）chlor- ①氯②绿chloro- ①氯②绿ciclo- 环cis- 顺clo- 氯crypto- 隐cycl- 环cyclo- 环de- 去；脱dec- 十；癸deca- 十；癸dehydro- 去氢；去水demethoxy- 去甲氧（基）demethyl- 去甲（基）deoxy- 去氧des- 去；脱desmethyl- 去甲（基）desoxy- 去氧dex- 右旋dextro- 右旋di- 二diamino- 二氨基diazo- 重氮dihydro- 二氢；双氢endo- 桥epi- 表；差向epoxy- 环氧erythro- 红；赤estr- 雌ethinyl- 乙炔（基）ethoxyl- 乙氧（基）ethyl- 乙基etio- 初eu- 优fluor- ①氟②荧光fluoro- ①氟②荧光formyl- 甲酰（基）guanyl- 脒基hepta- 七；庚hetero- 杂hexa- 六；己homo- 高(比原化合物多一个-CH2-)hypo- 次io- 碘indo- 碘iso- 异keto- 酮laevo- 左旋leuco- 白levo- 左旋。

氢氧化镍复合纳米材料的制备和电化学性能研究

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ｔｈｅｐｒｅｐａｒａｔｉｏｎ，ａｐｐｌｉｃａｔｉｏｎｓ，ｄｅｖｅｌｏｐｍｅｎｔｏｆｎａｎｏｍａｔｅｒｉａｌｓｗｅｒｅｇｅｎｅｒａｌｉｚｅｄｂｒｉｅｆｌｙ．
４．静止法．制备花状的氢氧化镍／金复合纳米薄膜。本法只是简单的将甲苯稀释的三乙胺（微量）滴在含有硝酸镍和金纳米的混合溶液的表面，短时间后，待甲苯挥发完，就会在气／液界面发现氢氧化镍／金的复合薄膜，本法制备的薄膜，同样是接触气体的一面较为光滑，在接触液体的一面可以看到颗粒花状的微观形貌。分别用膜的两面制备半胱氨酸、多巴胺、抗坏血酸以及葡萄糖的传感器进行循环伏安特性比较，发现复合薄膜的两面在这些传感器中性能相差不大，但是在碱性的电介质中，膜接触液体的一面存在较大的电容。
ｓｅｎｓｏｒｓｗｅｒｅｐｒｅｐａｒｅｄｒｅｓｐｅｃｔｉｖｅｌｙｂｙｂｏｔｈｓｉｄｅｓｏｆｔｈｅｍｅｍｂｒａｎｅｓｉｎｔｈｅｃｏｍｐａｒｉｓｏｎｏｆＣｙｃｌｉｃＶｏｌｔａｍｍｅｔｅｒ，ｔｈｅｒｅｗｅｒｅｆｅｗｄｉｓｔｉｎｇｕｉｓｈ．Ｈｏｗｅｖｅｒ，ｉｎｔｈｅａｌｋａｌｉｎｅｄｉｅｌｅｃｔｒｉｃ，ｏｎｅｓｉｄｅｏｆｔｈｅｍｅｍｂｒａｎｅｉｎｃｏｎｔａｃｔ、柝ｔｈｌｉｑｕｉｄｅｍｅｒｇｅｄａｌａｒｇｅｃａｐａｃｉｔａｎｃｅ．

一种固态电池用固态电解质包覆负极及制备方法

一种固态电池用固态电解质包覆负极及制备方法Solid-state batteries have garnered significant attention in recent years due to their potential to offer higher energy density, improved safety, and longer cycle life compared to traditional lithium-ion batteries. 固态电池由于其具有比传统锂离子电池更高的能量密度、更高的安全性和更长的循环寿命而受到了广泛关注。

One of the key components of solid-state batteries is the solid electrolyte, which plays a crucial role in enabling the flow of ions between the positive and negative electrodes. 固态电池的关键组成部分之一是固态电解质，它在正负极之间促进离子的流动起着至关重要的作用。

However, the development of solid electrolytes that can efficiently conduct ions while being mechanically and chemically stable remains a significant challenge. 然而，寻找一种在机械和化学稳定的同时能够高效导电的固态电解质仍然是一个重大挑战。

To address these challenges, researchers have been exploring new materials and fabrication methods for solid electrolytes, with a particular focus on the development of solid electrolyte coatings for the negative electrodes in solid-state batteries. 为了解决这些挑战，研究人员一直在探索固态电解质的新材料和制备方法，特别关注在固态电池中负极的固态电解质包覆的研发。

石墨纳米片复合物的有效热导率和电导率_英文_

Effective thermal and electrical conductivity of graphite nanoplatelet composites
Zhou Xiaofeng 1，2
2
Zhang Xiaosong 1源自Zhou Jiancheng 3
( 1 School of Energy and Environment， Southeast University， Nanjing 210096， China) ( Department of Fundamental Sciences， Yancheng Institute of Technology， Yancheng 224003， China) ( 3 School of Chemistry and Chemical Engineering， Southeast University， Nanjing 211189， China)
Abstract: The relationship between the thermal / electrical conductivity enhancement in graphite nanoplatelets ( GNPs ) composites and the properties of filling graphite nanoplatelets is studied． The effective thermal and electrical conductivity enhancements of GNPoil nanofluids and GNPpolyimide composites are measured． By taking into account the particle shape， the volume fraction， the thermal conductivity of filling particles and the base fluids， the thermal and electrical conductivity enhancements of GNP nanofluids are theoretically predicted by the generalized effective medium theory． Both the nonlinear dependence of effective thermal conductivity on the GNP volume fraction in nanofluids and the very low percolation threshold for GNPpolyimide composites are well predicted． The theoretical predications are found to be in reasonably good agreement with the experimental data． The generalized effective medium theory can be used for predicting the thermal and electrical properties of GNP composites and it is still available for most of the thermal / electrical modifications in twophase composites． Key words: graphite nanoplatelet; nanofluids; thermal conductivity; electrical conductivity; percolation threshold doi: 10． 3969 / j． issn． 1003 － 7985． 2013． 02． 009

静电纺丝法制备的多孔碳纳米纤维

静电纺丝法制备的多孔碳纳米纤维李静;乔辉;魏取福【摘要】用静电纺丝法制备了聚丙烯腈(PAN)/聚甲基丙烯酸甲酯(PMMA)复合纳米纤维,经预氧化、高温炭化,制备用作锂离子电池负极材料的碳纳米纤维(CNF).透射电子显微镜(TEM)和比表面积分析发现:制备的CNF具有多孔结构,比表面积达到572.9 m2/g,平均孔径为33.6 nm.以50 mA/g的电流在0.01～ 3.00V循环,制备的多孔CNF的首次放电比容量为333.3 mAt/g,第20次循环的可逆比容量为231.8 mAh/g,充放电效率近90％.%Polyacrylonitrile (PAN)/poly(methyl methacrylate) (PMMA) composite nanofibers were prepared by electrospinning technique,then porous carbon nanofibers (CNF) as anode material for Li-ion battery were obtained by pre-oxidation and high temperature carbonation. The analyses of transmission electron microscopy (TEM) and specific surface area showed that the as-prepared CNF had porous structure,the specific surface area was 572.9 m2/g,the mean pore size was 33.6 nm. When cycled in 0.01 - 3.00 V with the current of 50 mA/g,the initial specific discharge capacity of the as-prepared porous CNF was 333.3 mAh/g, the reversible specific capacity was 231.8 mAh/g at the 20th cycle, the charge-discharge efficiency was near 90% .【期刊名称】《电池》【年(卷),期】2011(041)003【总页数】3页(P132-134)【关键词】静电纺丝法;碳纳米纤维(CNF);多孔结构;负极材料;充放电性能【作者】李静;乔辉;魏取福【作者单位】江南大学纺织服装学院,生态纺织教育部重点实验室,江苏无锡214122;江南大学纺织服装学院,生态纺织教育部重点实验室,江苏无锡214122;江南大学纺织服装学院,生态纺织教育部重点实验室,江苏无锡214122【正文语种】中文【中图分类】TM912.9锂离子电池所用的碳负极材料,主要为石墨类材料和低温热解碳。

超级电容器用钒基纳米电极材料的研究进展_魏闯

网络出版时间：2017-01-17 11:27:19网络出版地址：/kcms/detail/35.1070.N.20170117.1127.008.htmldoi:10.6043/j.issn.0438-0479.201611063超级电容器用钒基纳米电极材料的研究进展魏闯，杨照，谢兵，李鸿乂（重庆大学材料科学与工程学院，重庆400044）摘要：超级电容器因其优越的性能成为了近年的研究热点。

电极材料是决定超级电容器电化学性能的关键，研究者们对各种超级电容器电极材料进行了广泛的研究。

钒元素具有可变价态，使得钒基化合物具有理论比容量高、电化学可逆性良好等优点，是一类极具潜力的超级电容器电极材料。

为了提升钒基电极材料的电化学性能，研究者们将其制备为纳米结构，或进一步与其他材料复合制备纳米复合材料。

本文归纳总结了近年来国内外对零维、一维、二维、三维钒基纳米材料作为超级电容器电极材料的研究进展，以期为超级电容器用钒基纳米材料的发展提供参考。

关键词：钒；纳米材料；超级电容器中图分类号：O614 文献标志码：A近年来超级电容器受到国内外学者的广泛关注。

与传统电容器、二次电池和燃料电池等相比，超级电容器具有以下优势[1-6]：1）功率密度高，是常规二次电池的数十倍；2）使用寿命长，能达到10万次以上；3）充放电速度快，一般充电只需几十秒到几分钟就可完成；4）使用温度范围广（-40~60℃）。

因此，超级电容器是一种极具潜力的新型储能元件。

超级电容器主要由电极材料、电解液、集流体等组成[4]。

电极材料是其中的关键部分，决定了超级电容器储能性能的优劣。

当前，超级电容器电极材料主要有碳基电极材料、导电聚合物电极材料以及过渡族金属化合物电极材料。

理想的超级电容器电极材料应具有良好的导电性、大的比表面积、适宜的孔径大小和孔隙分布、良好的电化学和机械性能等。

目前商品化的超级电容器电极材料均为碳基电极材料（一般不超过140 F/g），但其双电层储能机制限制了其比收稿日期：2016-11-29 录用日期：2017-01-15基金项目：国家重点基础研究发展计划（973计划）项目（2013CB632604）；国家科技支撑计划课题（2015BAB19B02）；国家自然科学基金面上项目（51474041,51674051）；中央高校基本科研业务费（106112016CDJZR135505）*通信作者：hongyi.li@电容的提高。

ldh基纳米复合材料的制备及吸附和电化学性能研究

LDH基纳米复合材料的制备及吸附和电化学性能研究重庆大学硕士学位论文（学术学位）学生姓名：***指导教师：张育新副教授专业：材料科学与工程学科门类：工学重庆大学材料科学与工程学院二O一四年五月Synthesis of LDH-based Nanostructuresnanomaterials and Their Adsorptopm Properties and Electrochemical PerformanceA Thesis Submitted to Chongqing Universityin Partial Fulfillment of the Requirement for theMaster’s Degree of EngineeringByHAO XIAO DONGSupervised by Associate Prof. ZHANG YuxinSpecialty：Material Science and EngineeringCollege of Material Science and Engineering ofChongqing University, Chongqing, ChinaMay, 2014摘要层状复合金属氢氧化物（Layered Double Hydroxides, LDH）是一类典型的阴离子型插层材料。

由金属氢氧化物构成主体层板，阴离子以及一些水分子等客体嵌入到层间形成独特的层状结构。

近年来，基于LDH独特的层状结构，以及层板离子可调控和层间阴离子可交换等特性，使得其在环境处理和能源储存等领域越来越受到关注。

本论文采用共沉淀法制备出ZnAl-LDH和CoAl-LDH，并以此为基利用自组装技术分别制备得到了Au/ZnAl-LDO，MnO x/ZnAl-LDO和MnO2/CoAl-LDH复合材料。

采用X射线衍射仪（XRD）、聚焦离子束扫描电镜（FIB/SEM）、透射电镜（TEM）、傅立叶红外吸收光谱（FT-IR）、同步热分析仪（TGA–DSC）和比表面积测试仪（BET）等表征手段对所得样品进行表征。

石墨烯_氧化钌纳米复合材料的水热法合成及电化学电容性能_英文_沈辰飞

收稿日期：2010-08-03。

收修改稿日期：2010-11-10。

江苏省自然科学基金(No.BK2006195)资助项目。

＊通讯联系人。

E -mail ：jmcao@石墨烯-氧化钌纳米复合材料的水热法合成及电化学电容性能沈辰飞1郑明波2薛露平1李念武1吕洪岭1张松涛1曹洁明＊,1(1南京航空航天大学材料科学与技术学院纳米材料研究所，南京210016)(2南京大学微结构国家实验室电子科学与工程学院，南京210093)摘要：通过水热法制备了石墨烯-氧化钌(G -RuO 2)纳米复合材料。

对样品进行了X 射线衍射(XRD)，扫描电子显微镜(SEM)，透射电子显微镜(TEM)和能量色散谱(EDS)表征。

SEM 结果表明氧化钌粒子均匀地分散在石墨烯层片上。

TEM 结果显示氧化钌纳米粒子的平均粒径约为3nm 。

对样品进行了循环伏安和充放电性能测试，结果表明在1A ·g -1的电流密度下，样品在H 2SO 4(1mol ·L -1)溶液中具有219.7F ·g -1的比电容。

关键词：氧化钌；石墨烯；纳米复合材料；电化学电容器；水热中图分类号：O613.71；O614.82+1文献标识码：A文章编号：1001-4861(2011)03-0585-05Graphene -RuO 2Nanocomposites:Hydrothermal Synthesis and ElectrochemicalCapacitance PropertiesSHEN Chen -Fei 1ZHENG Ming -Bo 2XUE Lu -Ping 1LI Nian -Wu 1L 譈Hong -Ling 1ZHANG Song -Tao 1CAO Jie -Ming ＊,1(1Nanomaterials Research Institute,College of Materials Science and Technology,Nanjing University ofAeronautics and Astronautics,Nanjing 210016,China )(2National Laboratory of Microstructures,School of Electronic Science and Engineering,Nanjing University,Nanjing 210093,China )Abstract:Graphene -ruthenium oxide (G -RuO 2)nanocomposite was prepared via a facile hydrothermal method.The sample was characterized by X -ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM)and energy dispersive X -ray Spectroscopy (EDS).SEM result reveals homogeneous distribution of RuO 2particles on the layers of graphene sheets.TEM images demonstrate that the average size of RuO 2particles is around 3nm.The electrochemical properties of the sample were examined by cyclic voltammetry (CV)and galvanostatic charge -discharge (GC).The specific capacitance value of the sample is about219.7F·g -1at the current density of 1A ·g -1in 1mol ·L -1H 2SO 4.Key words:ruthenium oxide;graphene;nanocomposites;electrochemical capacitor;hydrothermal method0IntroductionElectrochemical capacitors (ESCs)have attracted attention as electricity storage devices due to their higher power capability and longer cycle life compared with conventional double -layer capacitors [1-2].With longcyclelife and high specic capacitance,metal oxide and carbonaceous materials have been viewed as promising electrode materials for ESCs.Metal oxides such as RuO 2[3-7],MnO 2[8-9],NiO [10-11]and Co 3O 4[12-13]have been investigated for their electrochemical behaviors.Among them,electrochemical capacitors based on RuO 2第27卷第3期2011年3月Vol ．27No ．3585-589无机化学学报CHINESE JOURNAL OF INORGANIC CHEMISTRY第27卷无机化学学报electrode have been widely investigated due to their superior specfic capacitance,high electrochemical reversibility,and long cycle life[14-16].In terms of carbonaceous materials,carbon nanotubes[17-18],carbon fibers[19],carbon aerogels[20]and activated carbons[21]have been studied for their electrochemical behaviors.Graphene,a new kind of carbonaceous material,has been reported with unique properties and thus has drew great interests[22-23]. Vivekchand et al.[24]evaluated the capacitive behaviors of graphene and a capacitive performance of graphene up to117F·g-1in aqueous H2SO4solution was obtained.Stoller et al.[25]studied the electrochemical behaviors of graphene as the electrode of ESCs and a specfic capacitance of135F·g-1in5.5mol·L-1KOH aqueous electrolyte was achieved.Du et al.[26]used graphene as the electrode of ESCs to obtain a stable specfic capacitance of150F·g-1under specific current of0.1A·g-1for500cycles of charge/discharge. Recently,Du et al.[27]prepared functionalized graphene sheets(FGS)using graphite oxide(GO)as precursor via a low-temperature thermal exfoliation approach in air and the products exhibited good electrochemical behaviors.To harness the good electrochemical properties of both metal oxide and graphene sheets,one possible route is to integrate these two kinds of materials into the electrodes of ESCs.The capacitive performance of the composites will be enhanced largely because most of the metal oxide can contribute pseudo-capacitance to the total capacitance apart from the double-layer capacitance from graphene sheets[28-29].Yan et al.[30] synthesized graphene-MnO2composites through the self-limiting deposition of nanoscale MnO2on the surface of graphene under microwave irradiation and studied the electrochemical behaviors of the products. Son et al.[31]fabricated NiO Resistive Random Access Memory(RRAM)nanocapacitor array on a graphene sheet.In this work,we synthesized graphene-RuO2 nanocomposite with15wt%RuO2loading via a facile hydrothermal method and studied electrochemical characteristics of the products in an aqueous electrolyte.1Experimental1.1Preparation of FGSGO was prepared by Hummers method[32].To obtain FGS,certain amount of GO was thermally exfoliated at300℃for5min under air atmosphere and denoted as FGS300[27].1.2Preparation of G-RuO2All reagents were analytical grade and used without further purification.To prepare the sample with 15wt%RuO2loading of the composite,60mg FGS300 was dissolved in60mL distilled water.After vigorous stirring,a stable suspension was obtained.1.7mL of RuCl3(0.048mol·L-1)was then dropped into the suspension with ultrasonication for30min.Then,the solution was transferred into a Teflon-lined autoclave with a capacity of100mL,and then the autoclave was sealed and maintained at180℃for6h.After cooling to room temperature,the black product was washed with distilled water for several times,and dried under vacuum at50℃for48h.1.3CharacterizationThe dimension and the morphology of the sample were observed by SEM(Gemini LEO1530)and TEM (JEOL JEM-2100).Composition of the samples was analyzed using TEM attached energy dispersive X-ray spectroscopy(EDS).XRD patterns were recorded by a Bruker D8-Advance diffractometer using Cu Kαradiation(λ=0.15418nm)with the scanning2θangles ranging from10°to80°,a graphitic monochrom at40 kV and40mA.1.4Electrochemical testsCyclic voltammetry(CV)and galvanostatic charge-discharge(GC)were done in a three-electrode experimental setup using1mol·L-1H2SO4as electrolyte.The prepared electrode,platinum foil,and saturated calomel electrode(SCE)were used as the working,counter,and reference electrodes in1mol·L-1 H2SO4aqueous solution.The preparation of the working electrode for the three-electrode system was as follows: 80wt%G-RuO2sample,15wt%acetylene black,and 5wt%polytetrafluoroethylene were well mixed,then the mixture was pressed onto a stainless steel grid under10586第3期沈辰飞等：石墨烯-氧化钌纳米复合材料的水热法合成及电化学电容性能MPa.Each electrode contained 5.0mg of G-RuO2(active material).The CV and GC measurements werecarried out on CHI440A electrochemical workstation atroom temperature,the potential ranging from0V to1.0V(vs.SCE).The GC measurement was carried out incurrent density range of0.5~5A·g-1.2Results and discussionFig.1shows the XRD patterns of FGS300and G-RuO2nanocomposite.The characteristic(002)peak ofFGS300is clearly observed on the XRD patterns ofboth FGS300and G-RuO2[27].From a comparison ofthese two XRD patterns,no obvious diffraction peakscorresponding to RuO2are found in G-RuO2.It is supposed to be due to the small size of the RuO2 particles.Fig.2(a)shows the SEM image of FGS300.The wrinkle,a characteristic feature of graphene sheets,is observed.RuO2particles are observed decorated on the graphene sheets from Fig.2(b)and Fig.2(c).The uniform distribution of RuO2particles on graphene sheets guarantees the good electrochemical properties of G-RuO2[33].The HRTEM image(Fig.3(d))reveals the good crystalline nature of the nanoparticles.Besides, the size of the RuO2particles is observed to be around 3nm,which explains the low intensity of diffraction peaks of RuO2in the XRD pattern of the composite. The selected area electron diffraction(SAED)pattern in Fig.2(e)shows a ring pattern,indicating that the obtained RuO2particles are polycrystalline,which is consistent with the HRTEM observation.Moreover,the first ring matches the(110)plane of RuO2.The other rings are very close to both structures of Ru and RuO2,which may be due to incomplete oxidation of RuCl3[34].The EDS spectrum(Fig.1(f))reveals the existence of Ru and O species,of which the Ru and O elements should be the main contribution of RuO2 phase in the composite.CV and GC were used to investigate electrochemical behaviors of G-RuO2in a three-electrode system in1mol·L-1H2SO4electrolyte.Fig.3 (a)shows the CV curves of G-RuO2at different scan rates(5~50mV·s-1)in the potential range from0to1.0 Fig.1XRD patterns of FGS300and G-RuO2nanocompositeFig.2SEM images of FGS300and G-RuO2nanocomposite(a,b),TEM and HRTEM images of G-RuO2nanocomposite(c,d), SAED pattern of G-RuO2composite(e),EDS spectrum of G-RuO2composite(f)587第27卷无机化学学报Table 1Specific capacitances of G -RuO 2(C s,composite )obtained in 1mol ·L -1H 2SO 4from GC method andcapacitance retention for G -RuO 2V.Broad current peaks and almost mirror quasi -rectangular are observed in all the CV curves over theCV potential range.This indicates that the obtained G -RuO 2nanocomposite exhibits high redox reversibility and obvious pseudocapacitance character.[35]Galvanostatic cycling of G -RuO 2is performed ata current density of 0.5~5A ·g -1as shown in Fig.3(b).The specific capacitance of G -RuO 2(C s,composite )could be calculated from the slope of the charge -dischargecurves,according to the equation:C s,composite =I Δt [36],where I is the current of charge -discharge,Δt is the time of discharge,m is the mass of active materials in the working electrode,and ΔV is 1.0V.The calculated specfic capacitances of G -RuO 2at different scan rates and the capacitance retention of the samples are listed in Table 1.The results demonstrate high capacitance retention of the sample.Besides,atthe current density of 1A ·g -1,G -RuO 2exhibits capacitance value of 219.7F ·g -1,which is muchhigher than that of FGS300(119.1F ·g -1).The specific capacitance of RuO 2(C s,Ru )could be calculated basedon the equation:C s,Ru =C s,composite -(1-ωRu )C s,FGS300ωRu[33],where ωRu is the weight fraction of RuO 2within the nanocomposite,C s,FGS300is the specific capacitance of FGS300.At the current density of 1A ·g -1,C s,Ru iscalculated to be 789.8F·g -1.The distinguishing electrochemical behaviors of G -RuO 2are due to the excellent electrochemical properties of FGS300and the contribution of pseudocapacitance by RuO 2.With nanoporous structure,the obtained FGS300has fully accessible surface to electrolyte ion because both sides of a broad range of graphene sheets can be exposed to the electrolyte and contribute to capacitance [27].Furthermore,the residual functional groups on the surface of FGS may improve the hydrophilicity of electrode,which helps the RuO 2particles to be loaded onto the surface of FGS300.The RuO 2and the residual functional groups on graphene sheets all contribute to the pseudocapacitance and thus enhance the overall capacitance value of the composites.Fig.3(a)Cyclic voltammograms of G -RuO 2obtained at different scan rates.(b)Galvanostatic dischargecurves of G -RuO 2obtained at different current densities and FGS300at a current density of 1A ·g -1G -RuO 2233.6219.7200.7176.875.70.5A·g -11A ·g -12A ·g -15A ·g -1Sample C s,composite /(F ·g -1)Capacitance retention /%3ConclusionIn summary,graphene -RuO 2nanocomposite wasprepared via a facile hydrothermal method.The SEMand TEM characterizations reveal homogeneous distribution of RuO 2particles on graphene sheets.High capacitance value and capacitance retention of the composite are shown by capacitive behaviors of G -588第3期RuO2.References:[1]Winter M,Brodd R J.Chem.Rev.,2004,104:4245-4269[2]Pandolfo A G,Hollenkamp A F.J.Power 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原位拉伸研究热处理对激光选区熔化GH4169_合金组织及650_℃_力学性能的影响

2024 年第 44 卷航　空　材　料　学　报2024，Vol. 44第 1 期第 93 – 103 页JOURNAL OF AERONAUTICAL MATERIALS No.1 pp.93 – 103引用格式：朱嘉冕，吕国森，姜文祥，等. 原位拉伸研究热处理对激光选区熔化GH4169合金组织及650 ℃力学性能的影响[J]. 航空材料学报，2024，44(1)：93-103.ZHU Jiamian，LYU Guosen，JIANG Wenxiang，et al. Effect of heat treatment on microstructure and mechanical properties of selective laser melting GH4169 alloy at 650 ℃: in-situ SEM investigation[J]. Journal of Aeronautical Materials，2024，44(1)：93-103.原位拉伸研究热处理对激光选区熔化GH4169合金组织及650 ℃力学性能的影响朱嘉冕1, 吕国森1, 姜文祥1, 程晓鹏1, 贾泽一1, 吕俊霞1*,黄帅2, 张学军2（1．北京工业大学材料与制造学部，北京 100124；2．中国航发北京航空材料研究院，北京 100095）摘要：研究热处理制度对激光选区熔化成形GH4169合金组织及高温力学性能的影响。

通过自主研发的SEM原位加热拉伸测试平台，探究热处理前后650 ℃合金力学性能变化与动态组织演变的关系。

结果表明：热处理后合金的晶粒形态由柱状晶转化为等轴晶，Laves相溶解，析出大量γ′和γ′′强化相；在650 ℃下，沉积态合金的屈服强度和抗拉强度分别为574 MPa和740 MPa，热处理态（HSA态）合金的屈服强度和抗拉强度分别为818 MPa和892 MPa，较沉积态分别提升了42.5%和20.1%；沉积态合金表面晶粒起伏更大，协调变形能力更强，塑性流动能力好；裂纹在Laves相周围萌生沿枝状晶向最大切应力方向扩展，样品颈缩后发生剪切断裂；HSA态裂纹在碳化物周围萌生沿晶界扩展，断裂方式为沿晶和穿晶相结合的混合断裂。

Review-2012-NanoEnergy-Nanostructured electrodes for high-power lithium ion batteries

journal homepage: /locate/nanoenergyAvailable online at REVIEWNanostructured electrodes for high-power lithium ion batteriesRahul Mukherjee a,Rahul Krishnan b,T oh-Ming Lu c,Nikhil Koratkar a,b,na Department of Mechanical,Aerospace and Nuclear Engineering,Rensselaer Polytechnic Institute,Troy,NY12180,USAb Department of Materials Science and Engineering,Rensselaer Polytechnic Institute,Troy,NY12180,USAc Department of Physics,Applied Physics,and Astronomy,Rensselaer Polytechnic Institute,Troy,NY12180,USAReceived21March2012;received in revised form10April2012;accepted10April2012Available online26April2012KEYWORDSLithium-ion battery;Nano;Anode;Cathode;Power density;Energy densityAbstractLithium ion batteries are popular for use in portable applications owing to their high energy density.However,with an increasing interest in plug-in hybrid electric vehicles over the past few years,stemming from an urgent need to migrate to green technologies,the focus has shifted to enhancingpower densities in Lithium ion batteries.In this review article we focus on some of the recentachievements of the academic and industrial community in boosting the power densities of Lithiumion batteries through the development of novel nanostructured anode and cathode architectures.&2012Elsevier Ltd.All rights reserved.IntroductionLithium ion batteries offer very high energy densities anddesignﬂexibilities[1],thereby making them integral inmodern day consumer devices such as cellular phones,camcorders and laptop computers.However,unlike electro-chemical capacitors,lithium ion batteries are restricted tolow achievable power densities,as is evident from theRagone plot in Fig.1[2].With the advent of electricvehicles(EV)and plug-in hybrid electric vehicles(PHEV)there has therefore been a growing need to build lithium ionbatteries that can not only provide high energy densities butalso deliver high power densities in order to be consideredas a potential replacement for conventional gasolineengines.Lithium based rechargeable batteries wereﬁrst proposedby Whittingham in1976whereby he demonstrated rapid andhighly reversible intercalation reaction between lithium(anode)and layered titanium disulﬁde(cathode)[3].Lithium anodes,however,have a tendency to form dendriticgrowths that pose serious issues regarding safety[4]andaffect the cycle ability of the batteries[5].The concept oflithium ion batteries wasﬁrst introduced by Sony in1990asthey demonstrated the capability of non-graphitisable car-bon to insert lithium[6].Since then there has been a lot ofadvancement globally in theﬁeld of lithium ion batteries.2211-2855/$-see front matter&2012Elsevier Ltd.All rights reserved./10.1016/j.nanoen.2012.04.001n Corresponding author at:Department of Mechanical,Aerospace and Nuclear Engineering,Rensselaer Polytechnic Institute,Troy,NY12180,USA.Tel.:+15182762630;fax:+15182762623.E-mail address:koratn@(N.Koratkar).Nano Energy(2012)1,518–533Most of the research has primarily concentrated on improv-ing the performance of the cathode [7,8]and anode [9,10]materials and building a stable and more efﬁcient electro-lyte [11,12].A lithium ion battery essentially comprises of three compo-nents —cathode,anode and electrolyte.Cathodes are gen-erally categorized into three types,namely (1)lithium based metal oxides [13],such as LiCoO 2,(2)transition metal phos-phates [14,15],such as Li 3V 2(PO 4)3and LiFePO 4and (3)spinels [16]such as LiMn 2O 4.Among anodes,carbon is the typical material used in lithium ion batteries [17].However ,over the past few years the interest has shifted to other host materials capable of reversible lithium insertion such as silicon,tin,aluminum and germanium.More on this shall be described in the next section.Finally ,the electrodes are immersed in electrolytes that offer high ionic conductivity .The electrolyte most commonly used is based on lithium salts in aprotic solvents [18],for example LiPF 6in ethylene carbonate and diethyl carbonate (EC:DEC).The use of aqueous electrolytes [19]and solid [20]or gel type [21]polymer electrolytes in lithium ion batteries has also been reported in the literature.In addition,lithium ion batteries contain a separator to physically isolate the anode and cathode in order to ensure safe operation,while permitting ionic transport and preventing electronic ﬂow [22,23].In a lithium ion battery,lithium ions are extracted from the cathode during charging,transported through theelectrolyte and ﬁnally inserted into the anode.During discharge,lithium ions are extracted from the anode,transported through the electrolyte and inserted back into the cathode.Performance of the anode and cathode are generally quantiﬁed in terms of capacity per unit mass or per unit area of the electrode material,where capacity is the total number of ampere-hours that can be withdrawn from a fully charged cell under speciﬁed conditions of discharge [24].The nature of insertion and extraction,the operating voltage,capacity and cycle life are generally governed by the types of cathode and anode materials,the electrolyte and the rate of charge/discharge (C-rate).Apart from these,temperature of operation and storage also plays a crucial role in lithium ion batteries and signiﬁcant deterioration in performance has been reported at elevated temperatures attributed to factors such as irreversible electrolyte break down [25]and large self discharge [26].Performance deterioration with lower temperatures has also been observed in lithium ion batteries and is mostly attributed to the electrolyte characteristics [27].Although conventional electrolytes such as LiPF 6in EC:DMC:EMC or LiPF 6in EC:DMC have freezing points in the range of À301C to À501C,there is a drop in electrolyte conductivities with a decrease in the temperature by almost one order of magnitude [28].For instance,LiPF 6in EC:DMC:EMC has a conductivity of $1.1Â104s cm À1at room temperature which drops to $1Â103s cm À1at À401C.Irreversible losses in capacities and electrolytic break down thus pose a serious threat to the commercialization of advanced lithium ion batteries,especially in the automotive industry,where the battery would ideally be expected to operate over a wide temperature range.In this review we shall however focus on advancements in developing electrodes with good rate capabilities and high capacities as a stepping stone towards successful expansion of lithium ion batteries for high power and automotive applications.Lithium ion battery anodesCarbon has typically been favoured as anode materials in Lithium ion batteries,owing to its excellent cycling ability and long cycle life [29].Graphite compounds exhibit a theoretical capacity of 372mA h g À1of carbon correspond-ing to the formation of LiC 6as shown in Eq.(1)[30]Li þþ6C þe À"LiC 6ð1ÞIn addition,the diffusivity of lithium ions in graphite is exceptionally high,thereby facilitating rapid charging and discharging.The diffusion coefﬁcient of lithium ions can be effectively estimated incorporating cyclic voltammetry technique and Randles–Sevcik equation [31–33].The magni-tude of the peak current in a cyclic voltammetry plot is related to the scan rate through the Randles–Sevcik equa-tion as shown in Eq.(2).ip ¼0:4463nFAC nFVD RT 0:5ð2ÞIn the above equation,n represents the number of charges involved in the electrochemical half-reaction,F is Faraday’s constant (96,485C mol À1),A is the area of the electrode,C is the molar concentration of Li +in the electrolyte,V istheFigure 1Ragone plot of various types of batteries and capacitors.Lithium ion batteries exhibit high energy density values but suffer from poor power densities.In the current scenario when researchers and industries are actively seeking alternate energy sources for automotive and a variety of such other applications,it becomes increasingly necessary to develop a battery that will be capable of delivering both high energy and high power densities.Reprinted with permission from Ref.[2].Copyright 2008Nature Publishing Group.Nanostructured electrodes for high-power lithium ion batteries 519voltage sweep rate (V s À1),D is the diffusion coefﬁcient of lithium ions (cm 2s À1),R is the universal gas constant (8.314J mol À1K À1)and T is the absolute temperature (K).Since lithium ion batteries are primarily operated at room temperatures,Eq.(2)can be further reduced as follows.ip ¼kn 3=2v 1=2D 1=2ACð3ÞHere,k is a constant (2.69Â105C mol À1V À1/2).From Eq.(2),it can be seen that the peak current is a linear function of square-root of the sweep rate.By plotting the peak current for different scan rates,one can obtain the slope of the linear graph.Knowing this slope,n ,A and C ,the diffusion coefﬁcient of Li +can be calculated as follows.D ¼slope kn AC 2ð4ÞIn highly oriented pyrolytic graphite,the diffusion coefﬁ-cient of Li +in the direction parallel to the graphene plane has been reported to be as high as 4.4Â10À6cm 2s À1[34].Due to the inherent high diffusivity of lithium ions in graphite anodes,rapid charge and discharge is possible,thereby providing an opportunity to improve the available power signiﬁcantly.Extensive research on carbon based anode materials lead to the development of functionalized multiwalled carbon nano-tubes deposited using layer-by-layer technique that were able to provide power density as high as 100kW kg À1and demon-strated excellent cycle ability over a thousand cycles [35].However ,such carbon nanotube anode materials could deliver a reversible capacity of only $200mA h g À1.Carbon nanoﬁ-bers have also demonstrated capabilities of high rate cycling [36].In one such study ,carbon nanoﬁbers with diameters of 30nm and 230nm,heat treated at 10001C have demon-strated impressive rate capabilities.At current densities as high as 2A g À1,the capacities obtained were still above 100mA h g À1over 30charge/discharge cycles [37].More recently ,graphene (Fig.2)has attracted attention as potential anode materials in lithium ion batteries.Y oo et al.demon-strated [38]a reversible capacity as high as 784mA h g À1,thereby suggesting a possible adsorption of lithium on both sides of the graphene sheet leading to the formation of Li 2C 6[39,40].Additionally ,graphene has an inherently high con-ductivity which improves the charge transfer signiﬁcantly ,as shown by Su et al.in their recent study [41].However ,the same group demonstrated that graphene sheets blocked fast lithium ion transport (at rates of 3C and above),thereby limiting its application to high energy lithium ion batteries.Moreover ,the mass loading with graphene is extremely low and scalability of the system becomes a challenge.Wei and co-workers proposed a sputter deposited 1.1m m thick amorphous carbon ﬁlm capable of delivering high capacities with excel-lent coulombic efﬁciencies [42].Such sputter deposited amorphous carbon has inherent advantages when it comes to applications in lithium ion batteries.First,owing to high density of the deposited ﬁlm and the subsequent reduction in porosity ,the lithium ions can intercalate only through diffusion into the carbon material.This makes it easier for removal of lithium ions during the delithiation cycle as compared to delithiation of lithium ions from pore sites,thereby improving the reversible capacities.Given the high diffusion coefﬁcient of lithium ions in carbon,at low to moderate C-rates there will be an appreciable amount of lithiation in a 1.1m m thick ﬁlm.Moreover ,randomly oriented structure in the carbon ﬁlm facilitates more storage space for the lithium ions which further improves the obtainable capacities.Second,the deposited carbon ﬁlm has a very low surface area which reduces the formation of solid electrolyte interphase (SEI)which in turn limits the irreversible capacity loss.Finally ,such physical vapor deposition processes are carried out at high vacuum conditions which diminish the hydrogen concentration in the deposited ﬁlm.The presence of hydrogen in carbon has previously shown to have had a direct effect on increasing irreversible capacity loss [43].As a result of the aforementioned characteristics of sputter deposited carbon ﬁlms,initial discharge capacities as high as 987mA h g À1were obtained with a coulombic efﬁciency of 82%,which further improved over successive cycling.However ,the cycling behavior was demonstrated at low rates of 0.2C.Higher rates would result in partial diffusion of lithium ions in the ﬁlm which would drop the obtainable capacities.Therefore in order to achieve high power densities along with high capacities,alternate materials capable of insertinglithiumFigure 2(a)SEM and (b)cross-sectional TEM images of graphene nanosheets.Graphene has shown considerable promise as potential anode materials in lithium ion batteries due to their high capacities.Further research would be necessary however ,to improve the capacities during high rate applications of graphene-based anodes.One such approach could be by building an effective graphene based composite anode,employing secondary materials capable of better lithium intercalation kinetics.Reprinted with permission from Ref.[38].Copyright 2008American Chemical Society.R.Mukherjee et al.520ions have been investigated by researchers in theﬁeld.As a replacement for carbon based anode materials,some of the potential materials include Tin,Aluminum,Germanium and Silicon either in its pure form or as composites. AluminumAluminum has been envisioned as a suitable candidate for anode materials.The Al-Li phase diagram suggests that aluminum can form three possible alloys with lithium, namely AlLi,Al2Li3and Al4Li9[44].The Al–Li alloy corre-sponds to a capacity of993mA h gÀ1while Al4Li9alloy can deliver a gravimetric capacity as high as2234mA h gÀ1, owing to its light weight.However,the use of Al anodes in high power lithium ion batteries is largely restricted owing to a very slow lithium ion diffusion in aluminum.High power batteries require rapid insertion and extraction of lithium ions into the anode material.The diffusivity of lithium ions in aluminum is$6Â10À12cm2sÀ1,which results in only partial lithiation of the aluminum alloy[45].Moreover, aluminum also experiences as much as90%expansion in its volume,associated with the formation of Li–Al alloys. This rapid and extensive volume expansion leads to cracking and pulverization of the anode.Furthermore,it leads to delamination of the anode,thereby causing a loss in electrical contact.As a result,aluminum anodes have generally shown rapid capacity fading during subsequent cycling[46,47].The aforementioned factors have therefore prevented a full scale entry of aluminum anodes in high power lithium ion batteries.TinTin,on the other hand,offers several advantages over graphite as well as aluminum as anode materials in lithium ion batteries.Tin has a theoretical charge capacity of 994mA h gÀ1corresponding to the formation of Li4.4Sn alloy as shown in Eqs.(5)and(6).Moreover,it has a higher operating voltage,thereby providing a safer operation during rapid cycling[48].LiþþSnþeÀ-LiSnð5Þ3:4LiþþLiSnþ3eÀ-Li4:4Snð6ÞDiffusivity of lithium ions in tin is also signiﬁcantly high at 5.9Â10À7cm2sÀ1which allows for rapid charge/discharge cycles[49].Tin however,suffers from poor cycle life owing to tremendous volume expansion of as much as300%during alloying/dealloying reactions[50].There has however been a considerable effort aimed at addressing the aforemen-tioned issue.Recently,a novel three dimensional porous Sn–Cu alloy anode had been suggested that demonstrated stable capacities and high rate capabilities[51,52].Copper is an inactive material in the anode and does not participate directly in the lithium intercalation reaction.However, reaction involving intermetallic Cu6Sn5forms a ductile matrix that allows large volume expansion associated with Sn–Li alloying reactions,thereby improving the cycle life of the anodes.Foam based support matrices have especially helped improve the cycle life by relieving the induced strain during lithiation and delithiation cycles as demonstrated by the performance of Sn–Co alloy anodes supported on nickel foams[53].These anodes showed appreciable stability over 60cycles and a speciﬁc capacity as high as663mA h gÀ1.Tin oxides have also been considered as attractive candidates for anodes due to their high theoretical capacity of1491mA h gÀ1,good cycle ability and high coulombic efﬁciency[54–56].Li et al.demonstrated excellent capa-cities with SnO2nanoﬁbers(Fig.3(a)),prepared using a sol-gel synthesis method,when cycled at very high C-rates[57]. These nanoﬁbers performed better than thin-ﬁlms owing to higher surface area.Although,volume expansion was still visible in the nanoﬁbers,extensive disintegration of the electrode was prevented due to the superior ability of these nanoﬁbers to withstand volume changes(Fig.3(b)).Excel-lent cycle ability due to the aforementioned attributes was thus observed even at a rate as high as58C,as the cell delivered steady capacities over500mA h gÀ1through1400 charge/discharge cycles.Hybrid Sn nanoclusters–SnO2nano-ﬁbers have further boosted the capacities at moderate charge/discharge rates(0.1A gÀ1)[58].The presence of tin induces a reversible reaction between Sn and Li2O, produced during the reduction of SnO2nanowires,to further enhance the capacity and coulombic efﬁciency.Carbon nanotube(CNT)encapsulated SnO2composite anodes have also demonstrated a promise in improving the power densities of lithium ion batteries,whereby the strong,tubular CNT structures are incorporated to buffer the volume changes during lithium insertion and extraction. This has permitted incorporation of high C-rates with impressive cycle life due to the enhanced stability of the composite anode[59,60].With the advent of graphene, there has been an interest in SnO2-graphene composites with the hope that the high surface area and superior electrical conductivity of graphene could enhance the rate capability[61,62].CNT encapsulated structures also boost the cycle life of such anodes by providing a stable solid electrolyte interphaseﬁlm.Furthermore,graphene would prevent the agglomeration of SnO2particles and mitigate the volume changes,thereby enhancing cycle life. GermaniumGermanium and silicon have both received special interest as anode materials owing to their high theoretical capacities.The theoretical capacity of germanium is 1600mA h gÀ1while that of silicon is the highest reported capacity till date at4200mA h gÀ1,more than a10-fold increase from the theoretical capacities of graphite anodes. However,both Si and Ge suffer from three major draw-backs.First,being semi-conductors,the electrical resistiv-ities of both Si and Ge are signiﬁcantly higher at103O m and1O m,respectively.The poor conductivity leads to an inefﬁcient charge transfer during charge/discharge cycles. Second,the diffusivity of lithium ions is signiﬁcantly slower in Ge and Si.Lithium ions have very slow diffusion in silicon with a diffusion coefﬁcient as low as$10À12cm2sÀ1, thereby limiting the charge/discharge rates[63].Germa-nium,on the other hand,offers a$400times increase in the diffusivity of lithium ions as compared to silicon at room temperature[64],although the diffusion of lithium ions is still signiﬁcantly slower than that in carbon and tin basedNanostructured electrodes for high-power lithium ion batteries521anodes.Finally,both silicon and germanium have tremen-dous volume expansions between 300–400%.In order to develop high power lithium ion batteries incorporating Si or Ge anodes,it is necessary to overcome the aforementioned inherent characteristics of the two materials.Doping of germanium and silicon with phosphorus or boron has been established as a successful means to over-come the conductivity limitations in these materials [65–67].Higher conductivity induced in the anodes as a result of their doping in turn ensures efﬁcient charge transport.The poor diffusivity of lithium ions in germanium and silicon can be overcome by incorporating nanostruc-tured anodes.Nanostructuring the anodes signiﬁcantly reduce the diffusion distance for lithium ions,thereby permitting complete lithiation and delithiation even at high charge/discharge rates.Nanostructured anodes are often fabricated by means of physical vapor deposition methods such as sputtering.Addition of dopants to Si and Ge,enables simple dc sputtering of the target materials,thereby avoiding the need to adopt more complex r .f.sputtering or pulsed dc sputtering techniques.Not only does this reduce the cost of deposition,it also provides a relatively simple method for fabrication of such nanostruc-tured anodes.In spite of the relatively high cost of germanium,there has been an active interest in this material as anodes,especially since their applications are restricted to nanos-tructures or thin ﬁlms and the cost incurred at such scales is signiﬁcantly low.Germanium follows a three step electro-chemical reaction during its initial charge cycle as shown in Eq.(7)below [68].Ge -Li 9Ge 4-Li 7Ge 2-Li 15Ge 4þLi 22Ge 5ð7ÞFormations of Li 15Ge 4and Li 22Ge 5alloys induce a volume expansion of $270%,thereby affecting the structural integ-rity of the anode and its cycle ability.In order to accom-modate this rapid volume change,Park et al.fabricated novel hollow 0-D and porous 3-D Ge nanoparticles [69].The 3-D Ge nanoparticles in particular showed impressive integrity after 100cycles at a rate of 1C.The excellent structural integrity also ensured that there was very little capacity fading associated with pulverization or loss of electrical contact of the germanium nanoparticles.Germanium nanocrystals and amorphous thin ﬁlms have also demonstrated superior rate capabilities [70].Germanium thin ﬁlms,in particular ,demonstrated excellent capacity retention at lithiation rates of 1C and delithiation rates as high as 1000C.Bulk germanium on the other hand is incapable of charging at such high rates due to long diffusion distances and shows a rapid degradation in capacity over as few as 10cycles.Although,extremely high charging rate was obtained in this work,it is important to demonstrate high rate capability for both charge and discharge cycles.Butyl capped amorphous germanium nanoparticles have shown impressive performance at high C-rates in this regard [71].At low rates,amorphous germanium nanoparticles displayed a near theoretical capa-city of $1470mA h g À1.Interestingly ,even at a 5C rate,the anodes still delivered capacities of $1400mA h g À1.However ,amorphous Ge nanoparticles are severely affected by volume expansion.The electrodes fail to withstand such severe stress,thereby causing rapid loss in capacity .This necessitates the need to develop stable and structurally robust germanium anodes with an improved cycle life.Rapid charging and discharging with germanium anodes over 50cycles was recently demonstrated by incorporating germanium nanotubes (Ge-NT)[72].Ge-NTs,showninFigure 3(a)SEM image of SnO 2nanoﬁbers before cycling and (b)SEM image of SnO 2nanoﬁbers after 800charge/discharge cycles at 58C.Volume expansion due to lithiation is evident from the larger ﬁbril diameter post cycling.Formation of bulb-like structures at the ﬁbril tips suggest larger volume expansion at these sites due to higher lithiation and was attributed to availability of a larger surface area for lithium insertion here.At the tip,lithium can diffuse not only through the walls but also through the tip itself in a direction parallel to the ﬁber axis.In comparison,lithium diffusion is restricted only through the walls along the remaining length of the ﬁbers.Reprinted with permission from Ref.[57].Copyright 2001The Electrochemical Society.R.Mukherjee et al.522Fig.4(a),proved to be extremely effective in accommodat-ing volume expansion associated with lithiation of germa-nium.They demonstrated impressive rate capabilities as well,as shown in Fig.4(b).Germanium nanowires (Ge-NW)which allow for extensive volume changes without struc-tural degradation and offer improved charge transport efﬁciency by providing 1-D conductivity have also shown to be effective in allowing high rate cycling [73].At a discharge rate of 2C,Ge-NWs demonstrated capacities of almost 600mA h g À1with enhanced capacity retention.The improved capacity retention may however be attributed to the fact that at such high rates,there is only partial lithiation and delithiation which causes lower volume expansion in the anode as compared to volume expansion following complete lithiation cycles.Germanium and carbon based nanocomposite materials have also managed to boost the rate capabilities of lithium ion batteries by improved structural integrity in the anodes attributed to the inclusion of carbon [74,75]as carbon is far more stable towards charge/discharge cycles,experiencing a volume expansion of only $10%.SiliconSilicon remains one of the most attractive choice for anodes in lithium ion batteries,primarily due to its exceptional high theoretical capacities of 4200mA h g À1corresponding to the formation of Li 22Si 5as shown in Eq.(8).22Li þþ5Si þ22e À-Li 22Si 5ð8ÞHowever ,there are numerous challenges confronting the commercialization of Si anodes in lithium ion batteries.First,an extremely slow diffusivity rate of lithium ions in Si has prevented its use in high C-rate applications.On the other hand,use of ultra-thin Si ﬁlms restricts the mass scalability of Si anodes [76,77].Second,Si undergoes tremendous volume changes associated with insertion and extraction of lithium ions [78–80].This leads to cracking (Fig.5(a))anddelamination (Fig.5(b))of silicon from the substrate,all contributing towards a very poor cycle life of silicon anodes [81],as shown in Fig.5(c).Third,Si anodes suffer from poor electron transfer characteristics due to their inherently low conductivities.Finally ,the cycle ability of amorphous Si is also limited by the operating voltage.In situ XRD tests have shown evidence that discharging below 30mV leads to the formation of a new Li 15Si 4crystalline phase with poor capacity retention for ﬁlms with critical thickness of about 2.5m m [82,83].In spite of these limitations,the great promise that silicon holds due to its remarkable theoretical capacity have inspired researchers in the ﬁeld to actively seek solutions to overcome these challenges.The nanostructuring of silicon electrodes has helped over-come the aforementioned limitations to a considerable extent.Short diffusion distances in nanostructured electrodes permit nearly complete lithiation even at reasonably high charge/discharge rates.High rate capabilities due to short diffusion distances have already been demonstrated in silicon thin ﬁlms,although such thin ﬁlms still present a considerable challenge with respect to commercialization due to their very low mass loading [84,85].Silicon nanospheres developed by a solvo-thermal method could deliver high capacities at a moderate cycling rate of 0.5C [86].However ,it demonstrated very low capacity retention of $35.9%of the initial capacity over repeated cycling.Kim et ter showed an improve-ment in high rate capabilities and cycle life with 3D porous carbon coated Si particles [87].Even at a rate of 3C,the capacity retention was 72%while at 1C the capacity retention was an impressive 90%(Fig.6).Cui and co-workers further demonstrated the unique capabilities of nanostructured silicon by using crystalline silicon nanowires as anodes [88].These nanowires have a three-fold advantage over other nanoscale morphologies such as ﬁlms and rods.First,the nanowires had an average diameter of $89nm that could accommodate the volume expansion without undergoing fracture.Second,the nano-wires were directly grown onto the current collecting substrate that ensures participation of all thenanowiresFigure 4(a)TEM image of Ge-NT and (b)capacity vs.cycle number as a function of C-rate.The drop in capacity associated with high C-rates is attributed to low diffusivity of lithium ions.Higher rates allow lesser time for the lithium ions to insert into and extract from the host material,resulting in partial lithiation and lower than theoretical capacities.Reprinted with permission from Ref.[72].Copyright 2011WILEY-VCH Verlag GmbH &Co.KGaA,Weinheim.Nanostructured electrodes for high-power lithium ion batteries 523。

多通道碳阴极活化过一硫酸盐降解水中有机物的性能

大连理工大学硕士学位论文摘要活化的过硫酸盐氧化，作为一种新兴的高级氧化技术，是一种矿化难降解有毒污染物的有效方法。

在众多的活化方法中，过硫酸盐通过接受电子完成的电化学活化，具有容易操控和环境友好的特点，被认为是一种有前景的活化技术。

但在电化学活化的过程中，由于静电斥力阻碍了过硫酸盐阴离子和阴极之间的接触，导致过硫酸盐低的分解率和随后低的自由基的产生量，从而使污染物的降解效果变差。

针对此问题，本文使用天然木材衍生的碳化木（CW）制备了具有多通道的流通式阴极（FTC），通过将过一硫酸盐（PMS）阴离子限制在阴极的微通道中，能够显著地强化其与阴极的碰撞与接触，提高电化学活化的效率并增强对污染物的降解。

主要的研究成果如下：（1）通过天然松木的一步碳化制备并组装了具有丰富的介孔，良好的导电性，较高的机械强度，大量有序的微通道以及对PMS有良好的电催化活性的FTC。

以苯酚为目标污染物，探究了不同的反应条件（PMS浓度、电流密度和停留时间）对FTC电活化PMS降解苯酚性能的影响。

结果表明，在苯酚进水浓度为20 mg/L, 进水TOC=18 mg/L，进水PMS浓度为6.51 mM，背景Na2SO4为0.05 M，电流密度为2.75 mA/cm2，进水pH 2.87，停留时间10 min以及常温的条件下，通过FTC电活化PMS，PMS的分解率达到了71.9%。

苯酚和TOC的去除率分别达到了97.9%和39.6%。

EPR实验结果表明，在FTC电活化PMS的过程中，产生了大量的·OH和SO4•-。

同时，自由基淬灭实验也表明，·OH和SO4•-均参与了对苯酚的降解，且·OH对降解的贡献更大。

此外，五次循环实验的结果证明了本研究组装的FTC具有很好的稳定性。

（2）通过封闭CW的微通道，获得了流过式阴极（FBC）。

在相同的优化条件下，详细对比了在FTC中和FBC上的PMS的分解、自由基的产量以及电活化PMS降解三种酚类有机物（苯酚、双酚A和4-氯苯酚）的性能。

纳米木质素基多孔炭的制备及其电化学性能

化工进展Chemical Industry and Engineering Progress2022年第41卷第6期纳米木质素基多孔炭的制备及其电化学性能娄瑞1，刘钰1，田杰1，张亚男2（1陕西科技大学机电工程学院，陕西西安710021；2陕西科技大学化学与化工学院，陕西西安710021）摘要：基于绿色低共熔溶剂（DES ）高效分离麦草生物质组分以制备纳米木质素（LNP ），本文采用化学活化法并进一步热解炭化制备纳米木质素基多孔炭（LNPC ）。

借助SEM 、Raman 、BET-物理吸附等分析手段研究了锌系活化剂及热解炭化温度（600℃、700℃、800℃）对LNPC 的结构特征及电化学性能的影响。

研究结果表明，相对于LNP 直接热解炭化后纳米碳粒子的极易团聚，经锌化物活化后所制备的LNPC 表现出更好的分散性和多级孔道形貌结构。

尤其，以ZnCO 3活化后制备的LNPC-ZnCO 3-800具有更突出的性能，较高石墨化程度（I D /I G 为0.68）、较高BET 比表面积（679m 2/g ）、高介孔率（86.7%）、均匀纳米碳粒子构成的介孔结构。

此外，以LNPC-ZnCO 3-800制备的工作电极，在0.5A/g 时的比电容可达179F/g ，与直接热解炭化的LNPC-800（64F/g ）相比，其比电容的容量提高了180%。

关键词：纳米木质素；活化；热解；多孔炭；电化学中图分类号：TK6文献标志码：A文章编号：1000-6613（2022）06-3170-08Preparation of LNP-based hierarchical porous carbon and itselectrochemical propertiesLOU Rui 1，LIU Yu 1，TIAN Jie 1，ZHANG Yanan 2(1College of Mechanical and Electrical Engineering,Shaanxi University of Science and Technology,Xi ’an 710021,Shaanxi,China;2College of Chemistry and Chemical Engineering,Shaanxi University of Science and Technology,Xi ’an710021,Shaanxi,China)Abstract:Based on green deep eutectic solvent (DES),wheat straw biomass fractionations were efficiently isolated to prepare lignin nanoparticles (LNP).LNP-based carbon (LNPC)with hierarchical porous microstructure was prepared by chemical activation and further pyrolysis and carbonization.The influences of Zn-activators and pyrolysis temperatures (600℃,700℃,800℃)on the structural properties and electrochemical performances of LNPC were studied by means of SEM,Raman,BET analyzers,etc .The results proved that the activated LNPC with Zn-activators exhibited better dispersibility and more hierarchical porous morphology compared with LNPC from direct pyrolysis consisted of massive carbon nanoparticles aggregation.In particular,LNPC-ZnCO 3-800possessed outstanding performances on better graphitization (I D /I G =0.68),higher BET specific surface area (679m 2/g),more mesoporous pores (86.7%)and uniform carbon nanoparticles.Moreover,LNPC-ZnCO 3-800had a high specific capacitance of 179F/g at a current density of 0.5A/g,which was 180%higher than that of LNPC-800(64F/g).Keywords:lignin nanoparticles;activation;pyrolysis;porous carbon;electrochemical研究开发DOI ：10.16085/j.issn.1000-6613.2021-1567收稿日期：2021-07-23；修改稿日期：2021-09-18。