Zn掺杂对LiNi1/3Co1/3Mn1/3O2结构与电化学性能的影响

Effect of Zn Doping on the Structure and Electrochemical Performance of LiNi1/3Co1/3Mn1/3O2

摘要:

用溶胶凝胶法制备了LiNi1/3Co1/3-xMn1/3ZnxO2（x=0，1/24，2/24，4/24）锂离子电池正极材料。由X射线衍射和扫描电镜对其分析结果表明，Zn 掺杂不改变LiNi1/3Co1/3Mn1/3O2的α-NaFeO2层状结构，当掺杂量达到4/24时，杂相产生。电化学研究表明，当Zn掺杂量为2/24时，LiNi1/3Co1/3Mn1/3O2首次放电容量由未掺杂的169.2 mAh·g-1 降低为160.1 mAh·g-1，但循环性能明显提高，30次循环后的容量保持率由未掺杂的89.2%升至97%。并且在20、40、60和80 mA·g-1不同的电流密度下继续循环20次后，当再次恢复到20 mA·g-1的电流密度时，放电容量可恢复到150.3 mAh·g-1。

Abstract:

LiNi1/3Co1/3-xMn1/3ZnxO2 (x=0, 1/24, 2/24 and 4/24) cathode material for lithium-ion battery was synthesized by a sol-gel method. The results of XRD and SEM show that Zn doping does not change the α-NaFeO2 layer structure of LiNi1/3Co1/3Mn1/3O2, and impurity phases occur when the doped amount reaches 4/24. Electrochemical studies indicate that when the doped Zn content is 2/24, the initial discharge capacity of LiNi1/3Co1/3Mn1/3O2 decreases from 169.2 mAh·g-1 of the undoped material to 160.1 mAh·g-1. The cycling performance, however, is significantly improved. Compared with undoped material, the capacity retention rate of the sample of LiNil/3Col/3-xMnl/3ZnxO2 with x=2/24 increases from 89.2% to 97% after 30 cycles. The same sample was charged and discharged again at 20 mA·g?1 and the corresponding discharge specific capacity was restored to 150.3 mAh·g?1 after 20 cycles in different current densities of 20, 40, 60 and 80 mA·g-1.