石墨烯基锂离子电池复合负极材料的设计合成和性能研究

To develop new type of green lithium ion batteries with high capacity and long life-time has become the key for the breakthrough of lithium ion battery technology and is crucial to resolve the current environment and energy crisis. It also has inestimable significance for improving the living standard of human-beings. This project is electrochemical function-oriented and focuses on the design and controllable synthesis of graphene-based materials. We plan to grow active components of lithium ion battery anodes on graphene like nanorods, nanowires, nanoplates to form three dimensional (3D) hierarchical structures which possess high flexibility, conductivity and good electric contact due to the existence of graphene. Through thorough study of influencing factors and reaction conditions, we tend to obtain structural optimization strategies and controllable synthetic routes for graphene-based anode materials of lithium ion batteries with high electrochemical performance. We try to reveal the formation mechanism of the structures by researching on the chemical/physical interface behaviors between graphene layers and active components of anode materials. By studying the structure-activity relationship of the structure and electrochemical performance of graphene/lithium ion battery composite material, we try to understand the mechanism for transfer of electrons/lithium ions, electron transport and energy conversion in the compound structure. It provides new ideas and theoretical basis for developing new stable anode materials with high capacity and cycle performance for lithium ion batteries.

开发绿色环保高容量、长寿命的新型锂离子电池材料已成为突破锂离子电池技术的关键，这对解决当今环境和能源危机，提高人类生活水平具有不可估量的意义。本项目以锂离子电池电化学性能为功能导向，从结构设计和可控制备入手，开展在石墨烯表面生长一维或二维纳米结构的锂离子电池负极活性组分（如纳米棒、纳米线、纳米片），从而构筑成三维分级纳米复合结构，石墨烯赋予该结构高柔韧性、高导电性及良好的电接触等特性。深入探索构筑该结构的各种影响因素和反应条件，获得电化学性能优异的石墨烯基的锂离子电池负极材料的结构优化条件与可控制备新途径；研究石墨烯层与电池负极活性组分的界面物理/化学作用行为，揭示该结构的构筑机理；研究石墨烯/锂离子电池复合材料其结构与电化学性能间的构效关系，了解该复合结构中电子与锂离子扩散迁移、电子传输以及能量转化机制，为开发性能稳定、比容量高、循环性能好的新型锂离子电池负极材料提供新思路和理论依据。

石墨烯基复合材料由于具有高柔韧性、高导电性及良好的电接触，能够有效抑制高容量活性组分在锂离子电池充放电过程中的体积效应，在高电流密度下使得其循环寿命和倍率性能得到有效提升。本项目通过氧化石墨还原法制备了多种三维多孔石墨烯基复合材料，在优化的条件下获得高比容量及优异循环性能和倍率性能的电极材料。此外研究内容还扩展到了其他碳基复合材料的锂电性能研究，通过负载高容量的活性组分，结合多种合成策略并优化实验条件，获得兼具高比容量以及优异循环性能和倍率性能的电极材料。其中以普鲁士蓝类似物为前驱体制备的碳壳双金属碳化物纳米球，作为锂电负极材料取得了优异的电化学性能。在项目执行期间，利用其他有机分子碳源热解得到了多种类石墨烯碳材料和其他纳微形貌碳材料，它们具有高比表面积及优异的CO2气体吸附和电催化性能。本项目负责人以通讯作者身份在ACS Nano，Nano Energy，Chem. Mater.，J. Mater. Chem. A，Nanoscale，Carbon，J. Power Source等杂志上发表论文共76篇。项目重点解决了锂离子电池活性组分比容量低和循环稳定性差的问题，这些成果对于发展碳基复合材料，阐明材料纳微结构与电化学性能之间的关系，提供了理论基础和技术途径。