Dry coating and self-combustion reaction strategy for lithium residual removal and performance enhancement of Ni-rich oxide cathodes

Abstract

Dry coating application for Ni-rich layered oxide cathode materials is one attractive approach to improving the performance of rechargeable batteries due to their avoiding moisture sensitivity, damage to the layered structure, and environmental issues. However, surface impurities are still severe, causing capacity fading and poor electrochemical cycle life. Herein, we propose a simple dry aluminum oxide surface coating to build a stable surface structure and simultaneously effectively eliminate surface impurities. An exothermic reaction generates a high energy of 23,802 kJ/kg (at 300 °C) to remove LiOH and Li₂CO₃ surface impurities, and a lithium quantity from impurities transferred to the aluminum oxide forms a stability-conducive LiAlO₂ coating layer. Accordingly, the LiAlO₂ coating on Ni-rich oxide layered cathode materials demonstrates the high electrochemical performance of lithium-ion batteries. The results highlight a cost-effective and scalable coating process for cathode active materials, paving the way for large-scale cathode production in lithium-ion batteries.