自支撑硅/石墨烯/导电聚合物柔性电极可控制备及其储锂性能研究

Preparation of high-performance flexible electrode materials is prerequisite for the applications of the flexible lithium-ion batteries in the flexible electronic devices. Self-supporting flexible electrodes without metal current collectors and binders are expected to improve significantly the energy density of overall battery. To solve the problem that the decay of electrochemical performance for flexible electrodes during the bending state caused by the lack of bonding strength between the flexible substrate and electrochemically active materials, in this project, the dispersing silicon in the expanded graphene oxide matrix and reduction of graphene oxide will occur simultaneously during the pyrolysis of silane process, and then the bonding strength between silicon and graphene will be enhanced by means of conductive polymers. The parameters of expanded depth of graphene oxide, controllable growth of silicon nanoparticles, reduction of graphene oxide and the polymerization of conductive polymers will be optimized. The mechanism of enhanced bonding strength by conductive polymers will be revealed. The effects of mechanical flexible properties, morphology, composition, structure of flexible silicon/graphene/conductive polymers electrodes on the electrochemical performance under will be studied. The actualization of this project will provide academic foundation and reference for the research and application of high-performance flexible lithium-ion batteries.

高性能柔性电极材料的制备是柔性锂离子电池在可弯曲电子器件中应用的先决条件，无金属集流体和粘结剂的自支撑柔性电极能大幅提升整电池的能量密度。本项目针对柔性电极研究中柔性基体与电化学活性相之间因结合强度欠缺引起的电极弯曲状态下性能衰减现象，以膨胀氧化石墨烯为基体，在硅烷热解过程中实现纳米硅原位生成（分散）和氧化石墨烯还原同步进行，进而借助导电聚合物强化纳米硅与石墨烯之间的结合作用。项目将对氧化石墨烯深度膨化、纳米硅颗粒生长调控、氧化石墨烯气相还原、导电聚合物交联聚合进行参数优化并揭示导电聚合物结合强化机制。研究自支撑硅/石墨烯/导电聚合物柔性电极机械柔韧性能、形貌、组成、结构对电极在动态弯曲状态下电化学性能的影响规律。项目实施将为高性能柔性锂离子电池的研究与应用提供理论基础和实验支撑。

本项目针对柔性电极材料在弯曲和电化学循环过程中，基体与活性相之间易分离的问题，制备了自支撑活性材料/集流体一体化电极材料。该项目主要以石墨烯泡沫和柔性碳纤维纸为基体，通过掺杂以及与高容量硅、二氧化锡复合，获得了多种高性能自支撑电极材料。该电极材料无需粘结剂和集流体，显著提高了整电池的能量密度。通过引入有机碳源强化了活性相与柔性基体之间的结合力，保持了电极的结构稳定性。研究了柔性电极在循环前后结构、形貌的变化及对电化学性能的影响规律，获得了高容量、优异循环稳定性能和机械柔韧性能的锂离子电池负极材料。