Optimized Surface Engineering of Lithium-Rich Cathodes Via Temperature-Controlled Dual Coatings for Superior Electrochemical Performance

Abstract

Surface engineering of lithium-rich manganese-based cathode materials (LRMs) holds the key to overcoming challenges such as low initial coulombic efficiency and capacity degradation. This study introduces a novel temperature-controlled dual-coating strategy using ammonium phosphate ((NH4)2HPO4) to optimize the electrochemical performance of LRMs. By precisely regulating the calcination temperature, a stable dual-layer coating of spinel and Li3PO4 is achieved, significantly enhancing structural stability and electrochemical activity. At 400 °C, the optimized coating configuration improves initial coulombic efficiency (85.6%) and delivers a high discharge specific capacity of 156.1 mAh g−1 at 5 C, with 82.6% capacity retention after 150 cycles. The spinel layer effectively boosts capacity by inhibiting oxygen release and side reactions, while the Li3PO4 layer ensures stable cycling and mitigates phase degradation. Comparative analysis at varying temperatures reveals the critical roles of each coating component in delivering superior performance. This temperature-driven surface modification strategy provides a scalable approach for advancing high-performance lithium-ion battery cathodes.

Keywords: Temperature-controlled, Dual Coatings, lithium-rich manganese-based cathode, Spine phase, Li3PO4, cycling stability