层状硅酸盐基碳复合材料的制备及其锂存储性能研究

Energy storage materials with novel structure for lithium ion batteries have attracted wide attention. Layered structured materials such as graphite and LiCoO2 have shown outstanding properties and have been widely used in lithium ion batteries. The layered silicate is a very new type of energy storage materials for lithium ion batteries, because the layered structure provides a well-defined and facile lithium ion transportation route. However, layered silicate show a rapid capacity fading with cycles, as they are usually non-conductive. Recently, we have shown that the properties of layered silicate could be effectively improved after composited with carbon nanomaterials. Here, we envisioned that if the layered silicate could be in situ composited with carbon nanotubes or graphene with preciously controlled structure to form an effective conductive network (such as coaxial nanocables or sandwiched-like structure), the composites’ lithium ions and electron transportation properties would be improved. So the layered silicate/C composites could show a better capacity, cycling performance and rate capability, especially at high charge/discharge rates. Meanwhile, as a new type of anode material, the detailed lithium storage process is unclear. Further detailed investigation should be carried out. XRD、IR、solid state NMR and electrochemical measurement are used to characterize the charge/discharge process and investigate the lithium ion storage mechanism.

开发新型锂离子电池储能材料一直是能源领域的研究热点，以石墨、钴酸锂等材料为代表的层状结构表现出优异的锂存储性能和商业价值。本项目以层状结构硅酸盐为研究对象，通过与碳纳米管或还原氧化石墨烯等不同结构和维度的碳材料复合，构筑有助于电子传输的同轴纳米结构和面面二维复合的三明治结构，以提高电子在层状硅酸盐内部或材料间的传输性能；同时，利用层状结构的层间传质优势，改善锂离子在电极材料中的传输性能。两方面的协同效应有助于提高层状硅酸盐的充放电比容量、循环稳定性和倍率性能。探索出一条通过精确地结构设计和碳材料复合来改善层状硅酸盐锂存储性能的有效途径。此外，借助于原位和非原位的结构和电化学性质表征，研究锂离子在层状硅酸盐中的迁移过程，探讨储锂机理。

对能源需求的持续增长，新型储能材料和储能体系需要不断开发，以满足目前高能量密度、高功率密度的需求。层状硅酸盐的传质优势和过渡金属元素的电化学性质，使得其具有很高的科研价值和应用潜力，但是导电性差、不可逆容量高等缺点限制其发展。本项目通过与不同结构和维度的碳材料复合，构筑有助于电子传输的同轴纳米结构和面面二维复合的三明治结构，界面桥氧键有助于提高电子在电极材料内部或材料间的传输性能，继而提高层状硅酸盐的充放电比容量、循环稳定性和倍率性能。同时发现，材料的维度和复合效率显著影响材料储锂性能的发挥，探索出一条通过精确地结构设计和碳材料复合来改善层状硅酸盐锂存储性能的有效途径。此外，基于硅酸盐的反应性，构建了硅酸盐纳米材料结构设计的程序化方法，其在储锂、催化等领域均有很好的应用前景。