Li_(7-2z)La_(3)Zr_(2-z)Mo_(z)O_(12)表面包覆对Li_(1.2)Ni_(1.3)Co_(1.3)Mn_(0.54)O_(2)三元正极材料的影响

EFFECT OF Li_(7-2z)La_(3)Zr_(2-z)Mo_(z)O_(12) SURFACE COATING ON Li_(1.2)Ni_(1.3)Co_(1.3)Mn_(0.54)O_(2) TERNARY POSITIVE MATERIALS

以溶胶-凝胶法为基础,通过高温煅烧,使用Mo掺杂Li_(7)La_(3)Zr_(2)O_(12)(LLZO)材料包覆Li_(1.2)Ni_(1.3)Co_(1.3)Mn_(0.54)O_(2)(LNMCO)制备了LNMCO-LLZO-Mo_(z)(z=0、0.1、0.2、0.3)材料,决定了不同包覆量对复合材料结构,形貌中化学性能的影响。结果表明:Mo掺杂后的LNMCO-LLZO-Mo_(z)层状特性优于LNMCO-LLZO,其中LNMCO-LLZO-Mo_(0.2)材料相对致密、晶粒接触良好且具有最分明的形貌特征,团聚现象也最轻微;同时,LNMCO-LLZO-Mo_(z)材料循环性能也较为优异,其中LNMCO-LLZO-Mo_(0.2)材料在0.1 C倍率下的首圈放电比容量为234.229 mA·h/g,循环50圈后容量保持率为96.63%;在2.0 C的高电流密度下,首圈放电比容量为140.236 mA·h/g,高倍率下的循环稳定性较优,且具有最小的电荷转移阻抗R_(ct)。

Based on the sol-gel method,LNMCO-LLZO-Mo_(z)(z=0,0.1,0.2)was prepared by hight emperature calcination of the coated product forming by Mo-doped Li_(7)La_(3)Zr_(2)O_(12)(LLZO)coating on the surface of Li_(1.2)Ni_(1.3)Co_(1.3)Mn_(0.54)O_(2)(LNMCO).The effect of different coating amounts was also investigated.After analysis,it is found that the layered properties of Mo-doped LNMCO-LLZO-Moz are better than LNMCO-LLZO,and the LNMCO-LLZO-Mo_(0.2) material is relatively dense,with good grain contact,the most distinct morphological features,and the least agglomeration phenomenon.At the same time,the LNMCO-LLZO-Mo_(z) material has excellent cycle performance,and the first cycle discharge specific capacity of the LNMCO-LLZO-Mo_(0.2) material at a rate of 0.1 C is 234.229 mA·h/g,and the capacity retention rate after 50 cycles is 96.63%;At a high current density of 2.0 C,the first cycle discharge capacity is 140.236 mA·h/g,the cycle stability at high rates is better,and it has the smallest charge transfer resistance R_(ct).