锂离子电池用高倍率性能Li_4Ti_5O_(12)/MWNTs复合材料

High rate performance of Li_4Ti_5O_(12)/MWNTs composites for Li-ion batteries

通过溶胶凝胶法辅助的溶剂热法和热处理制备了Li4Ti5O12/MWNTs复合电极材料。进行了热重(TG)、X射线衍射(XRD)、扫描电子显微镜(SEM)、布鲁瑙尔-埃利特-特勒法(BET)等表征分析和电化学性能测试研究。与纯相的Li4Ti5O12相比,Li4Ti5O12/MWNTs具有较高的比表面积,更有利于锂离子的扩散;且MWNTs提供的三维导电网络状结构提高了复合材料的导电性,Li4Ti5O12/MWNTs具有更好的倍率性能和循环性能。在10 C下放电,比容量为140 mAh/g;经过300次循环其放电比容量仍有124 mAh/g,容量保持率为89%。

Abstract： Li4Ti5O12/multi-walled carbon nanotubes （MWNTs） composites were prepared by sol-gel method combined with solvothermal method and 2 h post-annealing. TG, XRD, SEM and BET were used to characterize their morphologies and structures, and their electrochemical properties were investigated by galvanostatic charge-discharge test. Compared with the pure Li4Ti5O12, Li4Ti5O12/MWNTs composites has higher specific surface area helpful to the diffusion of lithium ions, and has better rate capability and cycle performance, because MWNTs provide threedimensional conductive network structure improving the conductivity. The discharge specific capacity of the Li4Ti5O12/ MWNTs anode is 124 mAWg at 10 C, and the specific capacity remains 124 mAh/g with the capacity retention of 89% after 300 cycles.