负极材料LTO/G和LTO/Ag-G的合成及其电化学性能

Synthesis and electrochemical properties of LTO/G and LTO/Ag-G anode materials

采用溶剂热法制备锂离子电池负极材料Li_4Ti_5O_(12)/graphene(LTO/G)、Li_4Ti_5O_(12)/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 Li_4Ti_5O_（12）/graphene（LTO/G）,Li_4Ti_5O_（12）/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 and179.3 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.