硅石墨烯纳米复合材料作为锂离子电池负极材料的研究
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1.2 硅基负极材料的研究进展 ................................................................................... 1 1.2.1 不同形貌的纳米硅材料 ................................................................................ 2 1.2.2 硅-金属复合材料 ........................................................................................... 4 1.2.3 三维多孔结构的硅材料 ................................................................................ 4
1.1 锂离子电池概述 ................................................................................................... 1 1.1.1 引言 ................................................................................................................ 1 1.1.2 锂离子电池负极材料 .................................................................................... 1
关键词： 锂离子电池；纳米硅；石墨烯；静电自组装；三维多孔结构
I
哈尔滨工业大学工学硕士学位论文
Abstract
Owing to silicon exhibits the highest known theoretical specific capacity (4200mAh·g-1), which is expected to replace the traditional graphite anode and become newly anode material for lithium-ion battery. Unfortunately, the commercial application of silicon as an andoe material is hindered by the huge volume changes (>300%) and low electrical contact between silicon paticles during repeated charging/discharging, leading to dramatic pulverization of silicon particles and rapid capacity fading. In this paper, we improved the cycling performance of silicon anode by using graphene that has high specific surface area, excellent electrical conductivity and strong mechanical toughness. Specifically, we used electrostatic self-assembly to obtain Si/G composite, also fabricated three-dimensional(3D) porous Si/G composite via VC reduction and freeing-drying. Finally, we studied their structure and composition also with the electrochemical performance.
哈尔滨工业大学工学硕士学位论文
摘要
硅材料具有最高的理论比容量(4200mAh·g-1)，有望替代传统石墨负极，从而 成为锂离子电池的新型负极材料。但是硅在充放电过程中会发生巨大的体积膨胀 (>300%)，导致活性物质粉化脱落，硅颗粒间的电接触下降，容量迅速衰减，从而 阻止了其商业化应用。本课题通过利用石墨烯的高比表面积、优异导电性和强机 械韧性，有效提高了硅负极的循环性能。分别研究了由静电自组装法得到的 Si/G 复合材料和利用抗坏血酸(VC)还原、冷冻干燥制备得到的三维多孔结构 Si/G 复合 材料的结构组成和电化学性能。
Keywords: Lithium-ion battery; Nano-Si; Graphene; Electrostatic self-assembly; Three-dimensional po文
目录
摘 要 ............................................................................................................................... I Abstract ...........................................................................................................................II 第 1 章 绪论 .................................................................................................................... 1
We prepared the 3D porous structure of Si/G composite via VC reduction and freeing-drying. SEM and TEM texts proved that Si nanopaticles uniformly dispersed into graphene sheets, and graphene sheets stacked into each other to form a three-dimensional porous structure. TG text showed the mass fraction of graphene in the composite was 40.72%. This material exhibited good cycling performance, its reversible capacity kept at 756mAh·g-1 after 50 cycles. Pores in the 3D Si/G composite was formed via self-assembly of graphene sheets, which could effectively buffer the volume expansion of silicon in the process of lithiation and delithiation, promoted the penetration of electrolyte, also the fast transport of lithium-ion and electron.
国内图书分类号：TM912.9 国际图书分类号：621.3
学校代码：10213 密级：公开
工学硕士学位论文
硅/石墨烯纳米复合材料作为锂离子电池负极 材料的研究
硕 士 研 究 生：李国瑞
导
师：潘钦敏 教授
申 请 学 位：工学硕士
学
科 ： 化学工程与技术
所 在 单 位：化工学院
答 辩 日 期：2012 年 6 月
利用 VC 还原和冷冻干燥制备出了三维多孔结构的 Si/G 复合材料。SEM、TEM 测试表明该材料中纳米 Si 颗粒均匀分散于石墨烯片层，且负载着纳米 Si 粒子的石 墨烯片层相互堆叠形成三维多孔结构，TG 曲线表明石墨烯的含量为 40.72%。电化 学测试结果表明该材 料具有 良好的循环性能，50 次循环后可逆容量保持在 756mAh·g-1。这是因为载有纳米 Si 粒子的石墨烯片层自组装时形成的孔隙能够有 效缓解硅在脱嵌锂过程中的体积膨胀，并利于电解液的浸润、锂离子的扩散及电 子的快速传导。
The Si/G composite was prepared by electrostatic self-assembly. XRD, SEM, TEM tests proved that effective mixture between the nano-Si particles and graphene happened, and the result of TG text showed the content of graphene in the Si/G composite was 25%. The Si/G composite had better electrochemical performance than Si anode. When the current density is 200mA·g-1, the first delithiation capacity was 1061mAh·g-1, and its reversible capacity could remain at 707mAh·g-1 after 50 cycles, while Si anode only had 62mAh·g-1. The reason was that graphene connected Si nanoparticles to each other, which acted as a conductive network, prevented the aggregation of the Si particles and enhanced the electrical contact between the Si particles.
静电自组装法制备的 Si/G 复合材料，通过 XRD、SEM、TEM 等测试证明了 纳米 Si 粒子和石墨烯之间发生有效复合，且 TG 测试表明石墨烯在 Si/G 复合材料 中的含量为 25%。相比纯 Si 负极，该 Si/G 复合材料的电化学性能明显提高，在 200mA·g-1 的电流密度下首次脱锂容量 1061mAh·g-1，50 次循环后可逆容量保持在 707mAh·g-1，而纯 Si 负极仅有 62mAh·g-1。其原因在于石墨烯作为导电网络将纳米 Si 颗粒相互连接，阻止了 Si 颗粒的团聚，增强了 Si 颗粒间的电接触，提高了电子 导电性。
Candidate： Supervisor： Academic Degree Applied for： Speciality： Affiliation：
Date of Defence： Degree-Conferring-Institution：
Li GuoRui Prof. Pan Qin Min Master of Engineering Chemical Engineering and Technology School of Chemical Engineering and Technology June 2012 Harbin Institute of Technology
threedimensionalporousstructure哈尔滨工业大学工学硕士学位论文iii11锂离子电池概述111引言112锂离子电池负极材料12硅基负极材料的研究进展121不同形貌的纳米硅材料122硅金属复合材料123三维多孔结构的硅材料13硅石墨烯纳米复合材料131sig复合薄膜电极132sig纳米复合材料133sig三维多孔结构14本课题的研究目的和研究内容141研究目的142研究内容21实验药品及仪器设备211实验药品212仪器设备22静电自组装法制备sig复合材料10221sigo的静电自组装10222sigo的还原1223三维多孔结构的sig复合材料的制备1324电池的组装1325物理性能表征13251x射线衍射测试xrd13252扫描电子显微镜测试sem14253透射电子显微镜测试tem14254热重分析测试tg1426电化学性能表征14261循环伏安测试cv14262交流阻抗谱测试eis14263充放电测试以及倍率性能测试1631引言16哈尔滨工业大学工学硕士学位论文iv32sig复合材料的制备条件16321不同刻蚀溶剂对sig复合材料性能的影响16322不同hf用量对sig复合材料性能的影响18323不同sigo比例对sig复合材料性能的影响2033sig复合材料的结构表征22331xrd测试22332sem测试23333tem测试24334tg测试2534sig复合材料的电化学性能表征26341循环伏安cv测试26342充放电性能测试27343循环性能测试28344交流阻抗谱eis测试28345倍率性能测试2935本章小结3141引言3142三维多孔结构的sig复合材料的制备条件31421不同sigo比例的三维sig的伏安特性31422不同sigo比例的三维sig的充放电性能32423不同sigo比例的三维sig的循环性能3343三维sig复合材料的结构表征34431xrd表征34432宏观形貌34433sem表征35434tem表征36435tg表征3644三维sig复合材料的电化学性能表征37441循环伏安cv37442充放电性能38443循环性能39444交流阻抗谱eis39445倍率性能4045本章小结42参考文献43攻读学位期间发表的学术论文47哈尔滨工业大学硕士学位论文原创性声明49哈尔滨工业大学工学硕士学位论文1绪论11锂离子电池概述111引言进入21世纪能源短缺和环境污
授 予 学 位 单 位： 哈尔滨工业大学
Classified Index: TM912.9 U.D.C: 621.3
Dissertation for the Master Degree in Engineering
THE STUDY OF SI/GRAPHENE NANOCOMPOSITE AS ANODE MATERIALS FOR LITHIUM-ION BATTERIES
1.1 锂离子电池概述 ................................................................................................... 1 1.1.1 引言 ................................................................................................................ 1 1.1.2 锂离子电池负极材料 .................................................................................... 1
关键词： 锂离子电池；纳米硅；石墨烯；静电自组装；三维多孔结构
I
哈尔滨工业大学工学硕士学位论文
Abstract
Owing to silicon exhibits the highest known theoretical specific capacity (4200mAh·g-1), which is expected to replace the traditional graphite anode and become newly anode material for lithium-ion battery. Unfortunately, the commercial application of silicon as an andoe material is hindered by the huge volume changes (>300%) and low electrical contact between silicon paticles during repeated charging/discharging, leading to dramatic pulverization of silicon particles and rapid capacity fading. In this paper, we improved the cycling performance of silicon anode by using graphene that has high specific surface area, excellent electrical conductivity and strong mechanical toughness. Specifically, we used electrostatic self-assembly to obtain Si/G composite, also fabricated three-dimensional(3D) porous Si/G composite via VC reduction and freeing-drying. Finally, we studied their structure and composition also with the electrochemical performance.
哈尔滨工业大学工学硕士学位论文
摘要
硅材料具有最高的理论比容量(4200mAh·g-1)，有望替代传统石墨负极，从而 成为锂离子电池的新型负极材料。但是硅在充放电过程中会发生巨大的体积膨胀 (>300%)，导致活性物质粉化脱落，硅颗粒间的电接触下降，容量迅速衰减，从而 阻止了其商业化应用。本课题通过利用石墨烯的高比表面积、优异导电性和强机 械韧性，有效提高了硅负极的循环性能。分别研究了由静电自组装法得到的 Si/G 复合材料和利用抗坏血酸(VC)还原、冷冻干燥制备得到的三维多孔结构 Si/G 复合 材料的结构组成和电化学性能。
Keywords: Lithium-ion battery; Nano-Si; Graphene; Electrostatic self-assembly; Three-dimensional po文
目录
摘 要 ............................................................................................................................... I Abstract ...........................................................................................................................II 第 1 章 绪论 .................................................................................................................... 1
We prepared the 3D porous structure of Si/G composite via VC reduction and freeing-drying. SEM and TEM texts proved that Si nanopaticles uniformly dispersed into graphene sheets, and graphene sheets stacked into each other to form a three-dimensional porous structure. TG text showed the mass fraction of graphene in the composite was 40.72%. This material exhibited good cycling performance, its reversible capacity kept at 756mAh·g-1 after 50 cycles. Pores in the 3D Si/G composite was formed via self-assembly of graphene sheets, which could effectively buffer the volume expansion of silicon in the process of lithiation and delithiation, promoted the penetration of electrolyte, also the fast transport of lithium-ion and electron.
国内图书分类号：TM912.9 国际图书分类号：621.3
学校代码：10213 密级：公开
工学硕士学位论文
硅/石墨烯纳米复合材料作为锂离子电池负极 材料的研究
硕 士 研 究 生：李国瑞
导
师：潘钦敏 教授
申 请 学 位：工学硕士
学
科 ： 化学工程与技术
所 在 单 位：化工学院
答 辩 日 期：2012 年 6 月
利用 VC 还原和冷冻干燥制备出了三维多孔结构的 Si/G 复合材料。SEM、TEM 测试表明该材料中纳米 Si 颗粒均匀分散于石墨烯片层，且负载着纳米 Si 粒子的石 墨烯片层相互堆叠形成三维多孔结构，TG 曲线表明石墨烯的含量为 40.72%。电化 学测试结果表明该材 料具有 良好的循环性能，50 次循环后可逆容量保持在 756mAh·g-1。这是因为载有纳米 Si 粒子的石墨烯片层自组装时形成的孔隙能够有 效缓解硅在脱嵌锂过程中的体积膨胀，并利于电解液的浸润、锂离子的扩散及电 子的快速传导。
The Si/G composite was prepared by electrostatic self-assembly. XRD, SEM, TEM tests proved that effective mixture between the nano-Si particles and graphene happened, and the result of TG text showed the content of graphene in the Si/G composite was 25%. The Si/G composite had better electrochemical performance than Si anode. When the current density is 200mA·g-1, the first delithiation capacity was 1061mAh·g-1, and its reversible capacity could remain at 707mAh·g-1 after 50 cycles, while Si anode only had 62mAh·g-1. The reason was that graphene connected Si nanoparticles to each other, which acted as a conductive network, prevented the aggregation of the Si particles and enhanced the electrical contact between the Si particles.
静电自组装法制备的 Si/G 复合材料，通过 XRD、SEM、TEM 等测试证明了 纳米 Si 粒子和石墨烯之间发生有效复合，且 TG 测试表明石墨烯在 Si/G 复合材料 中的含量为 25%。相比纯 Si 负极，该 Si/G 复合材料的电化学性能明显提高，在 200mA·g-1 的电流密度下首次脱锂容量 1061mAh·g-1，50 次循环后可逆容量保持在 707mAh·g-1，而纯 Si 负极仅有 62mAh·g-1。其原因在于石墨烯作为导电网络将纳米 Si 颗粒相互连接，阻止了 Si 颗粒的团聚，增强了 Si 颗粒间的电接触，提高了电子 导电性。
Candidate： Supervisor： Academic Degree Applied for： Speciality： Affiliation：
Date of Defence： Degree-Conferring-Institution：
Li GuoRui Prof. Pan Qin Min Master of Engineering Chemical Engineering and Technology School of Chemical Engineering and Technology June 2012 Harbin Institute of Technology
threedimensionalporousstructure哈尔滨工业大学工学硕士学位论文iii11锂离子电池概述111引言112锂离子电池负极材料12硅基负极材料的研究进展121不同形貌的纳米硅材料122硅金属复合材料123三维多孔结构的硅材料13硅石墨烯纳米复合材料131sig复合薄膜电极132sig纳米复合材料133sig三维多孔结构14本课题的研究目的和研究内容141研究目的142研究内容21实验药品及仪器设备211实验药品212仪器设备22静电自组装法制备sig复合材料10221sigo的静电自组装10222sigo的还原1223三维多孔结构的sig复合材料的制备1324电池的组装1325物理性能表征13251x射线衍射测试xrd13252扫描电子显微镜测试sem14253透射电子显微镜测试tem14254热重分析测试tg1426电化学性能表征14261循环伏安测试cv14262交流阻抗谱测试eis14263充放电测试以及倍率性能测试1631引言16哈尔滨工业大学工学硕士学位论文iv32sig复合材料的制备条件16321不同刻蚀溶剂对sig复合材料性能的影响16322不同hf用量对sig复合材料性能的影响18323不同sigo比例对sig复合材料性能的影响2033sig复合材料的结构表征22331xrd测试22332sem测试23333tem测试24334tg测试2534sig复合材料的电化学性能表征26341循环伏安cv测试26342充放电性能测试27343循环性能测试28344交流阻抗谱eis测试28345倍率性能测试2935本章小结3141引言3142三维多孔结构的sig复合材料的制备条件31421不同sigo比例的三维sig的伏安特性31422不同sigo比例的三维sig的充放电性能32423不同sigo比例的三维sig的循环性能3343三维sig复合材料的结构表征34431xrd表征34432宏观形貌34433sem表征35434tem表征36435tg表征3644三维sig复合材料的电化学性能表征37441循环伏安cv37442充放电性能38443循环性能39444交流阻抗谱eis39445倍率性能4045本章小结42参考文献43攻读学位期间发表的学术论文47哈尔滨工业大学硕士学位论文原创性声明49哈尔滨工业大学工学硕士学位论文1绪论11锂离子电池概述111引言进入21世纪能源短缺和环境污
授 予 学 位 单 位： 哈尔滨工业大学
Classified Index: TM912.9 U.D.C: 621.3
Dissertation for the Master Degree in Engineering
THE STUDY OF SI/GRAPHENE NANOCOMPOSITE AS ANODE MATERIALS FOR LITHIUM-ION BATTERIES