聚丙烯腈基聚合物电解质的研究进展

聚丙烯腈基聚合物电解质的研究进展化学化工学院班级：2009131144周明香学号：2009131144专业：化学任课教师：王丽萍2011年12月19日聚丙烯腈基聚合物电解质的研究进展摘要：详细介绍了锂离子电池用PAN(聚丙烯腈)基聚合物电解质的发展过程,提出了PAN基凝胶型聚合物电解质所存在的主要问题,介绍了PAN的改性方法。

关键词：凝胶、聚合物、电解质、聚丙烯腈随着便携式电子器件的不断小型化，二次电池也要向质量轻超薄的方向发展。

而聚合物锂离子电池具有比能量高，无电解液泄漏问题、安全性能好、设计灵活、易于大规模生产等特点。

因此倍受市场的青睐。

聚合物电解质是聚合物锂离子电池的核心部分，它需要具有较高的电导率和电化学稳定性，良好的机械性能以及与电极的相容性，目前所开发出的聚合物电解质体系主要有PEO[1～4]、PMMA[5～6]、PVDF[7～10]、PVC[11]、PAN[12]几大类,还有许多新体系的电解质也在尝试之中。

但能应用于生产的却不多，这是因为大多数聚合物电解质体系难以同时具有较高的电导率和良好的机械强度。

1.研究进展1975年Feuillade和Perche[13]首次研究制备出PAN-PC-NH4ClO4三元凝胶聚合物电解质，后来Abraham[14]等作了深入研究，这类聚合物电解质是通过在聚合物基质中固化大量的液态电解质溶液而制成的,其电导率已达到1X10-3S/cm数量级。

近年来对凝胶型聚合物电解质的研究发展很快,并取得了较大的成就。

PAN是一种稳定性好、耐热性强且阻燃性好的聚合物，较为适合用作基质材料,采用有机电解液对其进行增塑后，可形成凝胶电解质。

随着对微观结构、界面性质以及导电机理研究的深入,其性能有了较大的提高。

Watanabe[15]等在PAN-LiClO4聚合物体系中加入EC(碳酸乙烯酯)、PC(碳酸丙烯酯)、DMF(二甲基甲酰胺)等塑化剂,结果发现电导率随着塑化剂与LiClO4摩尔比率的增加而增加,最大电导率在25℃时可达10-4～10-5S/cm，Appetecchi[16]等研究了一种组成为PAN-EC-DMC-LiPF6(16-60-20-4摩尔比)+A12O3(6wt.%,w/o)的新型凝胶电解质，在25℃时离子电导率可达3 X 10-3S/CM，而且电化学稳定窗口很宽，与锂离子界面稳定性也较好。

但是因为这些研究中各种合成、制备工艺较为复杂，而且条件高，不能达到聚合物锂离子动力电池的技术指标，因此难用于实际生产。

Megahed[17]等人用复合增塑剂对PAN进行改性,室温离子传导率达4×10-3S/cm,锂离子迁移数也大大提高到0.6～0.7之间。

Kim D[18]等用乳液聚合法合成了AN-MMA-LiClO4-EC/PC聚合物电解质，在室温下的离子电导率达 1.9×10-3S.cm-1，而且保液性好，放电容量为130mAhg-1。

Jayathilaka等[19]制备了PAN/EC/PC/LiTFSI的凝胶聚合物电解质，在室温条件下，当PAN(15.4%)/EC(41.0%)/PC(41.0%)/LiTFSI(2.6%) (质量比) 时，电导率为 2.5×10 -3S.cm-1。

Hyo-Sik Min[20]等应用倒相法制备PAN膜，将PAN膜浸泡在不同的电解液中:1 M LiClO4-EC-DMC, 1M LiPF6-EC-DMC 和1M LiBF4 EC-DMC (体积比为1:1)，用扫描电镜观察了膜在浸泡前后的变化，测得其电化学稳定压均在5.0V以上，其中PAN-LiPF6-EC-DMC电解质在室温时的离子电导率为2.8×10-3S/cm。

Fang Yuan[21]等将不同用量的AN与不同分子量的PEO共聚制备成固体聚合物电解质，控制AN的用量，当PEO分子量为3000000时其室温电导率最大可 6.79×10-4S.cm-1。

2.存在的主要问题CROCE[25-27]等人对PAN基凝胶聚合物电解质（GPE）进行了系统的研究，选择不同的溶剂、不同的锂盐，以不同的配比制备出PAN基凝胶聚合物电解质，通过比较离子电导率、电化学窗口、伏安循环性能、阳离子迁移数和GPE与电极的相容性，发现PAN基GPE的室温离子电导率一般在10-3S/cm数量级，最高可达到5.9 ×10-3S/cm(LiPF6/EC/DMC/PAN)，研究发现：由于PAN链上含有强极性基团―CN，与金属锂电极相容性差，凝胶聚合物电解质膜与锂电极界面钝化现象严重，随着时间的延长，电池内阻会不断增大。

此外PAN的结晶性强，当温度上升时，电解液容易发生析出，从而又转化为液体电解质，导致漏液问题严重。

这些问题限制了PAN 体系GPE在锂离子二次电池中的应用。

从实用化角度来看PAN基聚合物电解质还存在一些问题需要解决，主要体现在热力学稳定性和机械强度较差，电极界面稳定性欠佳。

机械强度差是凝胶型聚合物电解质普遍存在的问题。

为了提高电导率，就需要在PAN 基质中固化较多的增塑剂，而增塑剂含量的增加又会使其机械性能下降。

因此，在保持较高电导率的情况下提高其机械强度是研制凝胶型PAN 基聚合物电解质的一个难点。

3.PAN基聚合物电解质改性为了提高PAN基凝胶型聚合物电解质的性能,人们尝试了多种方法对其进行改性,目前改性的办法一般有共聚、共混、交联、添加无机填料等，这样不仅可以改善电解质与电极的界面稳定性，还可以使GPE的机械性能有较大的提高。

Choi[28]等人把PAN和PEO共混制备得到PEO/PAN-LiC104-EC/BL组成的凝胶聚合物电解质膜，离子电导率为1.2×10-3S/cm, PEO的加入提高了PAN凝胶的机械强度。

Kim y[29]等把PAN和PANI共混制备得到PAN-PANI-EC/BL-LiClO4组成的凝胶聚合物电解质，离子电导率达1.9×10-3S/cm，电化学稳定性能、电极界面的相容性都有所改善，但是其机械性能差。

Kim D[30-32]等人采用丙烯腈-甲基丙烯酸甲酯-苯乙烯三元共聚物为基体制备的凝胶电解质，与以PAN均聚物为基体的凝胶电解质相比，与电极界面的相容性改善很多，组成Li/PAN基GPE/Li电池的界面电阻在10天内由224Ω增加到436Ω，但从第10天到第30天，界面电阻变化很小。

Lee[33]等在PAN链上引入了甲基丙烯酸锂盐(LIMA)制备了P(AN-LIMA)离聚物，在LiC104+EC电解质中，25℃时离子电导率为1.9 ×10-3 S/CM。

研究者采用交流阻抗法测试了P(AN-LIMA)电解质膜与电极间阻抗随时间的变化情况，从图1可知，PAN基电解质经30d后，界面阻抗增加了近3倍，而P(AN-LIMA)电解质基本没有增加，同样的，他们还发现经过20次循环伏安后P(AN-LIMA)电解质与电极间界面阻抗无明显增加，但纯PAN基电解质却增加了数倍，他们认为，P(AN-LIMA)界面稳定性提高的原因是LIMA与EC中氧原子相互作用，从而阻止了增塑剂EC的偏析。

此外，向GPE中添加适量的无机填料也可以改善电解质膜/锂电极的界面稳定性。

SLane[34]等用沸石粉末对PAN基凝胶电解质进行改性，制备了LiAsF6-EC-PC-PAN-沸石复合聚合物，图2是不同存放时间后聚合物电解质与电极间阻抗随时间的变化情况，尽管图2(b)初期界面阻抗较大，但再随时间增加，其增加量很小，由此可知，沸石粉末的加入可以起到减缓界面阻抗增加，明显改善了其界面性质。

Panero[35]等人在PAN/LiPF6/PC体系中加入A12O3粉末制成凝胶电解质，在25℃的离子电导率可达8×10-3S/cm，电化学化学稳定窗口达5.5V，特别适用于高电压可充电锂离子电池中作为电解质隔层。

参考文献[1] LaikB,legrandL,ChausseAetal.J.Electrochem.Soc.,1999,146(5):1672.[2] AppetecchiGB,CroceF,PersiLetal.ElectrochimicaActa,2000,45:1481.[3] MunichandraiahN,ShuklaAK,ScanlonLGetal.ElectrochimicaActa,2000,45:1203.[4] AndreevYG,BurcePG.ElectrochimicaActa,2000,45:1417.[5] TatsumaT,TaguchiM,OyamaN.ElectrochimicaActa,2001,46:1201.[6] AgnihotrySA,Pradeep,SekhonSS.ElectrochimicaActa,1999,44:3121.[7] SaitoY,CapigliaC,YamamotoH.J.Electrochem.Soc.,2000,147(5):1645.[8] AbrahamKM,KochVR,BlakleyTJ.J.Electrochem.Soc.,2000,147(4):1251.[9] MichotT,NishimotoA,WatanabeM.ElectrochimicaActa,2000,45:1347.[10] BoudinF,AndrieuX,JehouletCetal.J.PowerSources,1999,81-82:804.[11] RajendranS,UmAT.J.PowerSources,2000,87:218.[12] AppetecchiGB,ScrosatiB.ElectrochimicaActa,1998,43(9):1105.[13]Feuillade G,Perche .Ion-conductive macromolecular gels and membranes for solid lithium cell[J],J Appl Electrochem, 1975,5(1):63-68.Polyacrylonitrile and the research progress of polymer electrolyteAbstract: introduced the lithium ion battery with PAN (polyacrylonitrile) and the development process of polymer electrolyte, and put forward the PAN and gel polymer electrolyte type of the existing main problems, this paper introduces the modification methods of PAN.Keywords: gel, polymer, electrolyte, polyacrylonitrileAlong with the continual miniaturization of portable electronic devices, secondary battery and to light quality ultra-thin direction. And polymer lithium ion battery is better than the high energy, no electrolyte leakage problem, safety performance is good, design flexibility, easy to mass production etc. Characteristics. So much market favour. Polymer electrolyte, polymer lithium ion battery core part, it needs to have higher electrical conductivity and electrochemical stability, good mechanical properties and the compatibility and electrode, the creation of polymer electrolyte system mainly PEO [1 ~ 4], PMMA [5 ~ 6], PVDF (7 ~ 10], PVC [11], [12] a few kinds big PAN, and many of the new system in electrolyte also trying. But can be applied to the production of but not much, this is because most polymer electrolyte system has high conductivity to at the same time and good mechanical strength.1. The research progress1975 Feuillade and Perche [13] first study the preparation PAN-PC-NH4ClO4 three yuan gel polymer electrolyte, Abraham later [14] the thorough research, this kind of polymer electrolyte is through in a polymer matrix curing a large amount of liquid electrolyte solution of made the conductivity has reached 1 X10-3 S/cm orders of magnitude. In recent years to gel type of polymer electrolyte research and development soon, and made great achievements. PAN is a kind of good stability, heat resistance and flame retardancy good strong polymer, a suitable used as a matrix materials, using organic electrolyte to its plasticized, can form a gel electrolyte. As the core of the micro structure, interface properties and the deepening of the research conductive mechanism, the performance of alarge improvement.Watanabe [15], etc in the PAN-LiClO4 polymer system with EC (ethylene carbonate esters, PC (TanSuanBingXi ester), DMF (DMF) plasticizing agent, and found the conductivity plasticizing agent and with LiClO4 Moore ratio increases with the increase in 25 ℃maximum conductivity can reach up to 10-4 ~ 10-5 S/cm, Appetecchi [16] of a PAN-EC-DMC-LiPF6 (16-60-20-4 Moore than) + A12O3 (6 wt. %, w/o) new gel electrolyte, 25 ℃in when ionic conductivity up to 3 X 10-3 S/cm, and electrochemical stability window is very wide, and lithium ion interface stability is better also. But because these studies various synthesis, preparation technology is relatively complex, and conditions high, cannot achieve polymer lithium ion power battery technology index, so difficult for practical production.[17] Megahed, using composite plasticizer to PAN on modification, room temperature ionic conduction rate up to 4 x 10-3 S/cm, lithium ion migration number also greatly improved to 0.6 to 0.7. [18] Kim D by emulsion polymerization synthesizedMMA-AN-LiClO4-EC/PC polymer electrolyte, the ionic conductivity at room temperature of 1.9 x 10-3 S. Cm-1, and the liquid sex good, discharge capacity for 130 mAhg-1. Jayathilaka [19] such as prepared PAN/EC/PC/LiTFSI gel polymer electrolyte, at room temperature, when PAN (15.4%) / EC (41.0%) / PC (41.0%) / LiTFSI (2.6%) (quality than), the conductivity of 2.5 x 10-3 S. Cm-1. Hyo-Sik Min [20] applications pour in PAN method for film, will be soaked in different PAN film electrolyte: 1 M LiClO4-EC-DMC, 1 M LiPF6-EC-DMC and 1 M LiBF4 EC-DMC (volume ratio of 1:1), with scanning electron microscopy (sem) in the film before and after soaking, the change of the electrochemical stability measured pressure are in the 5.0 V above, includingPAN-LiPF6-EC-DMC electrolyte the ionic conductivity at room temperature for 2.8 x 10-3 S/cm. Fang Yuan [21] will be different with different molecular weight of the amount of AN PEO copolymerization of preparation into solid polymer electrolyte, control of AN amount, when PEO molecular weight for 3000000 when the room temperature conductivity can be biggest 6.79 x 10-4 s. cm-1.2. The main problems of theCROCE [25-27] to PAN the gel polymer electrolyte (GPE) on the system research, choose different solvents, different lithium, with different proportion of preparation and gel polymer electrolyte PAN out, by comparing ionic conductivity, electrochemical window, voltammetric circulation performance, cationic migration number and GPE with electrodes compatibility, found the room temperature, GPE PAN ionic conductivity in general 10-3 S/cm orders of magnitude, the highest reaches 5.9 x 10-3 S/cm (LiPF6 /EC/DMC/PAN), the study found: because in the chain of PAN with strong polar groups-CN, and lithium metal electrodes compatibility is poor, gel polymer electrolyte membrane and lithium electrode interface passivation phenomenon seriously, with the extension of time, the internal battery will increase. In addition the crystallization of the PAN with strong sex, when the temperature rises, electrolyte prone to exhalation, thus and into liquid electrolyte, lead to serious leakage problems. These problems limits the GPE PAN system in lithium-ion secondary battery of application.From the practical Angle and polymer electrolyte PAN also exist some problems to be solved, mainly reflects in thermodynamic stability and mechanical strength is poorer, electrode interface poor stability. Mechanical intensity difference is gel type polymer electrolyte common problem. In order to improve conductivity, they need in the PAN in matrix curing more plasticizer, and the increase of the content of plasticizer and will make its mechanical properties fall. Therefore, in high conductivity of mechanical strength is developed to improve the gel type, the polymer electrolyte PAN a difficulty.3.PAN and polymer electrolyte modification In order to improve the PAN and gel polymerelectrolyte type of performance, people tried several methods to its modification, at present the modification to the general copolymerization, blending, crosslinking, adding inorganic materials, such not only can improve the stability of the electrolyte with electrodes interface, still can make GPE mechanical performance is greatly raised.Choi [28] the PAN and PEO people of mixed preparation get PEO/PAN-LiC104-EC/BL gel polymer electrolyte of membrane, ionic conductivity of 1.2 x 10-3 S/cm, PEO to joinimprove the PAN gel mechanical strength. [29] Kim y the PAN and PANI blending preparation PAN-PANI-get EC/BL-LiClO4 composition gel polymer electrolyte, ionic conductivity of 1.9 x 10-3 S/cm, electrochemical stable performance, electrode interface compatibility are improved, but its mechanical performance is poor.Kim D [30-32] people using acrylonitrile-methyl methacrylate (mma)-styrene three yuan for the preparation of copolymer matrix gel electrolyte, and to all homopolymers as matrix PAN gel electrolyte compared with electrodes of the interface to improve compatibility many, Li/PAN of the GPE/Li battery interface resistance in 10 days Ωincreased to 436 from 224 Ω, but from the day 10 to 30 days, interface changes very little resistance.[and] in Lee PAN chain introduced methylacrylic acid lithium (LIMA) preparation the P (AN-LIMA) from homopolymers, in LiC104 + EC electrolyte, 25 ℃to 1.9 when ionic conductivity x 10-3 S/CM. The researchers used the method of ac impedance test P(AN-LIMA) electrolyte membrane with electrodes over time between the changes of impedance, from figure 1, it is known that the yankees by 30 d PAN electrolyte, interface impedance increased almost 3 times, and P (AN-LIMA) electrolyte basic did not increase, the same, they also found that after 20 times cycle after current-voltage P (AN-LIMA) electrolyte and electrode interface without obvious increase between impedance, but pure PAN and electrolyte actually increased the number of times, they think, P (AN-LIMA) interface stability was the reason for the increase in LIMA and EC oxygen interaction, and so stop plasticizer segregation of EC. In addition, GPE to the addition of appropriate amount of inorganic packing can also improve electrolyte membrane/lithium electrode interface stability.[34] SLane with zeolite powder to the gel electrolyte PAN on modification, the preparation LiAsF6-EC-PC-PAN-zeolite composite polymer, figure 2 is different storage time polymer electrolyte and after between electrodes impedance changing with time, although figure 2 (b) initial interface impedance is larger, but to increase with time, the amount is small, as you can see, zeolite powder to join can rise to slow the increase interface impedance, can significantly improve the its interface properties.Panero [and] in PAN/LiPF6 / PC system to join A12O3 made gel electrolyte powder, 25 ℃in the ionic conductivity can reach 8 x 10-3 S/cm, electrochemical chemical stability window of 5.5 V, especially suitable for high voltage rechargeable lithium ion batteries as a layer between the electrolyte.reference[1] LaikB,legrandL,ChausseAetal.J.Electrochem.Soc.,1999,146(5):1672.[2] AppetecchiGB,CroceF,PersiLetal.ElectrochimicaActa,2000,45:1481.[3] MunichandraiahN,ShuklaAK,ScanlonLGetal.ElectrochimicaActa,2000,45:1203.[4] AndreevYG,BurcePG.ElectrochimicaActa,2000,45:1417.[5] TatsumaT,TaguchiM,OyamaN.ElectrochimicaActa,2001,46:1201.[6] AgnihotrySA,Pradeep,SekhonSS.ElectrochimicaActa,1999,44:3121.[7] SaitoY,CapigliaC,YamamotoH.J.Electrochem.Soc.,2000,147(5):1645.[8] AbrahamKM,KochVR,BlakleyTJ.J.Electrochem.Soc.,2000,147(4):1251.[9] MichotT,NishimotoA,WatanabeM.ElectrochimicaActa,2000,45:1347.[10] BoudinF,AndrieuX,JehouletCetal.J.PowerSources,1999,81-82:804.[11] RajendranS,UmAT.J.PowerSources,2000,87:218.[12] AppetecchiGB,ScrosatiB.ElectrochimicaActa,1998,43(9):1105.[13]Feuillade G,Perche .Ion-conductive macromolecular gels and membranes for solid lithium cell[J],J Appl Electrochem, 1975,5(1):63-68.。