负极材料LTO/G和LTO/Ag-G的合成及其电化学性能

摘要

采用溶剂热法制备锂离子电池负极材料Li4Ti5O12/graphene(LTO/G)、Li4Ti5O12/Ag-graphene(LTO/Ag-G).通过 X 射线衍射仪(XRD)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM) 和电池测试系统对合成的样品进行结构、形貌及电化学性能表征.结果表明:Ag纳米粒子(20~50 nm)均匀分布在石墨烯表面,在石墨烯和银微粒的协同作用下,LTO/Ag-G复合材料具有优良的电化学性能.该材料在0.2C和1C倍率下首次放电比容量为205.3 mA.h/g和179.3 mA.h/g;在1C倍率下,循环40次后放电比容量仍为149.6 mA.h/g.因此,LTO/Ag-G复合材料具有较好的倍率性能和循环性能,是一种理想的锂离子动力电池负极材料.%The lithium ion batteries anode materials Li4Ti5O12/graphene(LTO/G), Li4Ti5O12/Ag-graphene(LTO/Ag-G) were fabricated by solvothermal method. X-ray diffractometry(XRD), field emission scanning electron microscopy(FE-SEM), transmission electron microscopy (TEM) and battery testing system were employed to characterize the structure, morphology and electrochemical properties of the as-prepared materials. The results show that Ag nanoparticles (20-50 nm) disperse well on the surface of graphene, the LTO/Ag-G composites deliver the outstanding electrochemical performance, which is attributed to the synergetic effect of the Ag particles and graphene. The electrochemical tests present that the initial specific discharge capacities of LTO/Ag-G composites are 205.3 mA.h/g and 179.3 mA.h/g at 0.2C and 1C, respectively, and maintain at 149.6 mA.h/g after 40 cycles at 1C, which indicates that the LTO/Ag-G composite is a promising anode material for lithium ion batteries with higher rate capability and cycling stability.