Surface modification of Ni-rich LiNi0.8Co0.1Mn0.1O2 with perovskite LaFeO3 for high voltage cathode materials

Abstract

Ni-rich LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) is regarded as a potential cathode material due to its higher capacity. However, the severe capacity fading which occurs above 4.2 V vs. Li/Li⁺ needs to be addressed to enhance the electrochemical performance. Herein, we report the surface modification of NCM811 cathodes with a perovskite material, i.e., lanthanum iron oxide (LaFeO₃), which has drawn attention for various research areas due to its non-toxicity, electric conductivity, chemical stability, and low cost and systematically investigate the influence of the LaFeO₃ coating on NCM811. The LaFeO₃ coating layer significantly protects the cathode material from corrosion due to the HF formation and restrains the dissolution of other ions into liquid electrolyte during high voltage charge–discharge processes. Even after 80 cycles, 0.5 wt% LaFeO₃-coated NCM811 cathode material shows about 13% higher cycling stability when compared to the bare NCM811 and other ratios of coated materials. Furthermore, the 0.5 wt% LaFeO₃-coated NCM811 delivers excellent rate capability and demonstrates improved structural stability at 4.6 V vs. Li/Li⁺ under high voltage conditions with Ni-rich cathode active materials.