Co-Effect of AlF₃ and MgF₂Coating on the Electrochemical Performance of LiNi_1/3Co₁_/3Mn_1/3O₂ Cathode Material under High Voltage

Abstract

AlF3 and MgF2 were applied to modify the surface of the LiNi1/3Co1/3Mn1/3O2 cathode material. The structural and electrochemical properties of the materials were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), charge–discharge tests and electrochemical impedance spectra (EIS). The results show that the 1 wt.% AlF3 and 1 wt.% MgF2 coated LiNi1/3Co1/3Mn1/3O2 (NCM333) cathode material exhibits an optimized electrochemical performance. It presents an initial capacity of 207.2mAh/g and 169.1mAh/g at 0.2C between 2.8V and 4.7V after charge-discharge 65 cycles. The rate performance is also enhanced because the coating decreases the interface charge transfer impedance.