Regulating the Evolution Pathway of the Cathode Electrolyte Interphase to Stabilize Li-Rich Cathode Materials

Abstract

Inorganic components of the cathode electrolyte interphase (CEI) are key to enhance the electrochemical performance of Li-rich cathode materials. However, optimizing inorganic components to stabilize CEI is still a great challenge due to the complex interfacial side reactions in the cycling process. Herein, the inorganic components of the CEI are modulated by constructing a heteroepitaxial spinel@layered interface on the surface of Li-rich materials via H₃BO₃-assisted solvothermal post-treatment. The spinel@layered interface regulates the evolution pathway of CEI and the decomposition pathway of the LiPF₆-based electrolyte by altering the inherent surface catalytic properties of Li-rich materials, thereby in situ-forming the Li₃PO₄-dominated CEI. The robust Li₃PO₄-rich CEI inhibits electrolyte decomposition, shields the cathode from various side reactions, and prevents the layered-to-spinel phase transition, thus significantly improving the electrochemical performance of Li-rich cathode materials. The treated Li-rich oxide exhibits 83.9% and 84.9% capacity and voltage retention after 150 cycles at 200 mA/g, much better than the pristine Li-rich cathode. The findings provide new insights into the regulation of CEI components in improving the electrochemical performance of Li-rich oxide materials.