高镍三元LiNi0.8Co0.1Mn0.1O2@Li2ZrO3正极材料的表面修饰与电化学性能优化

Boosting Electrochemical Performance of Ni-rich LiNi0.8Co0.1Mn0.1O2@Li2ZrO3 Cathode Material via the Surface Modification

利用正丁醇锆的水解反应,以碳酸锂为锂盐前驱体,在高镍三元LiNi0.8Co0.1Mn0.1O2(NCM811)颗粒表面成功制备均匀且完整包覆的Li2ZrO3(LZO)纳米包覆层,厚度约为18nm。循环伏安(Cyclic Voltammetry,CV)和电化学交流阻抗(Electrochemical Impedance Spectroscopy,EIS)测试结果表面,摩尔质量分数为1 mol%的Li2ZrO3表面修改层能有效地抑制高镍三元NCM811正极材料与电解液之间的界面副反应,降低了其循环过程中的电化学极化,从而提高了正极材料的循环稳定性和倍率性能。在工作电压为2.7V-4.3Vvs.Li+/Li和电流密度为1C条件下,经包覆处理的NCM811@LZO正极材料首次放电比容量为177.5mAh/g,50次循环后保持在143.9mAh/g,均高于纯NCM811正极材料的149.3mAh/g和136.6mAh/g。

Ni-rich LiNi0.8Co0.1Mn0.1O2(NCM811)particles have been modified by the Li2ZrO3(LZO)coating layer through the hydrolysis of tetrabutyl zirconate,followed by the postannealing with the lithium carbonate.The Li2ZrO3 coating shows desired structural uniformity and conformality with the thickness at approximately 18 nm.Electrochemical measurements involving Cyclic Voltammetry(CV)and Electrochemical Impedance Spectroscopy(EIS)indicate that the Li2ZrO3 coating at a molar ratio of NCM811∶LZO=1∶1%can effectively restrict side reactions between Ni-rich NCM811 particles and electrolyte,resulting in reduced electrochemical polarity and enhanced cycling stability and rate capability.The NCM811@LZO cathode material can deliver an initial discharge capacity of 177.5 mAh/g at 1 Cin a voltage range of 2.7 V-4.3 V vs.Li+/Li and retain 143.9 mAh/g after 50 cycles,which are superior to that of the bare NCM811 cathode(149.3 mAh/g and 136.6 mAh/g).