Li_7La_3Zr_2O_(12)表面包覆层对LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2电化学性能改善研究

Synthesis Li_7La_3Zr_2O_(12) Surface Modification on LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2 as Cathode Material for High Reversible Lithium-ion Batteries

采用共沉淀方法合成锂电池正极材料LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2的前驱体,进而高温固相反应生成LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2(LNCM),由于所得正极材料含有的Ni、Mn元素与电解液发生微量副反应,导致材料电化学性能降低.为改善LNCM材料的循环性能和倍率性能,采用导电性能优良的快离子导体Li_7La_3Zr_2O_(12)(LLZO)对LiNi_(1/3)Co_(1/3)Mn_(1/3)O_2进行表面修饰,制得几种不同表面包覆比例的LLZO@LNCM材料.研究发现,LNCM和LLZO@LNCM材料在0.1 C倍率下的首次放电容量相似,而LLZO@LNCM的循环性能和倍率性能则有明显改善.

In this paper, LiNi1/3Co1/3Mn1/3O2 （LNCM） is synthesized by solid-state sintering based on the precursor that is prepared by co-precipitation. To improve the cycle performance and rate performance of LNCM, a surface modifed on LNCM particles using Li7La3Zr2O12 （LLZO） is synthesized and studied. The crystal morphologies and crystal structure of the as-synthesized samples are characterized by X-ray difraction （XRD） patterns, transmission and scanning electron microscopy （TEM and SEM）. The initial discharge capacities of the bared LNCM before and after LLZO coatings at 0.1 C-rate are similar values. However, the cyclic performance and rate performance of LNCM coated by LLZO present much better value than the bare LNCM.