高比能量锂离子电池硅基负极材料研究进展

硅的理论嵌锂比容量是石墨材料比容量的十倍以上, 脱锂电位低, 资源丰富, 倍率特性较好, 故高比能量的硅基材料成为了电动汽车?可再生能源储能系统等领域的研究热点?但由于其在脱嵌锂过程中巨大的体积膨胀效应会导致硅电极材料粉化和结构崩塌, 并且在电解液中硅表面重复形成的固相电解质层(SEI)使极化增大?库伦效率降低, 最终导致电化学性能的恶化?为了解决上述问题, 加快实现硅基电极的商业化应用, 本文系统总结了通过硅基材料的选择和结构设计来解决充放电过程中体积效应的工作, 并深入分析和讨论了具有代表性的硅基复合材料的制备方法?电化学性能和相应机理, 重点介绍了硅碳复合材料和SiO_x(0<x≤2)基复合材料?最后对硅基负极材料存在的问题进行了分析, 并展望了其研究前景?

Silicon-based Anode Materials Applied in High Specific Energy Lithium-ion Batteries: a Review

Silicon has the highest theoretical lithium insertion specific capacity, more than ten times the theoretical specific capacity of graphite electrode material, and low delithiation potential, with abundant resources and good rate characteristics, high-energy-density lithium-ion battery silicon-based materials have become hot spots in application fields such as electric vehicles and renewable energy storage systems. However, it will cause powdering and structural collapse of the silicon electrode material due to its large volume expansion effect in the process of delithiation and lithium insertion. In addition, the solid electrolyte interface (SEI) layer on the surface of silicon is repeatedly formed in the electrolyte, which increases the polarization and reduces the coulomb efficiency, eventually leading to deterioration of electrochemical performance. In order to solve the above problems and realize the commercial application of silicon electrodes. This paper systematically summarizes the work to solve the volume effect in charge and discharge process through the selection and structural design of silicon-based materials, and deeply analyzes and discusses the preparation methods, electrochemical properties and corresponding mechanisms of representative silicon-based composite materials, focusing on silicon-carbon composites and SiO_x (0<x≤2) based anode materials. Finally, the problems of silicon-based anode materials are analyzed and their prospects are prospected.