In Situ Formed Heterostructure Interface and Well-Tuned Electronic Structure Ensuring Long Cycle Stability for 4.9 V High-Voltage Li-Rich Layered Oxide Cathodes.

High-voltage lithium-rich manganese-based layered oxides (LMLOs) are considered as the most competitive cathode materials for next-generation high-energy-density lithium-ion batteries (LIBs). However, LMLOs still suffer from irreversible lattice oxygen release, uncontrollable interface side reactions, and surface structural degradation. Herein, we propose an integration strategy combining La/Al codoping and Li x CoPO 4 nanocoating to improve the electrochemical performance of LMLOs comprehensively. La/Al codoping regulates the electronic structure to enhance the redox activity of anions and cations and inhibit structural degradation. The Li x CoPO 4 nanocoating formed by in situ reaction with the surface residual lithium can not only promote Li-ion migration but also reduce interfacial side reactions. The induced Layered@Rocksalt@Li x CoPO 4 heterostructure suppresses lattice volume variation and structural degradation during cycling. Under the synergistic effect of the heterostructure interface and well-tuned electronic structure, the capacity retention rate of comodified LMLO materials reaches 80.06% after 500 cycles (2.0-4.65 V) and 75.1% after 340 cycles at 1C under a high cut-off voltage of 4.9 V.