Cooperative Bulk-Interface Regulation Through Na/F/Al Functional Synergy Enables Structural and Interfacial Stability in Li-Rich Layered Oxides.

Abstract

Lithium rich manganese layered oxides (LRMs) are promising cathode materials for high energy lithium-ion batteries owing to their high capacity and low cost, yet their practical applications are limited by lattice degradation and unstable cathode electrolyte interphase (CEI) evolution during cycling. Herein, a fluorine enriched multifunctional Li1.2Mn0.54Ni0.13Co0.13O2(LRM) is constructed through Na+, F-, and Al3+ synergistic regulation to achieve bulk surface stabilization. The introduction of Na+ broadens Li interlayer spacing and accelerates Li+ transport, while Al-O bonding stabilizes the local electronic structure, suppresses cation disorder and Jahn-Teller distortion, and alleviates lattice strain. Furthermore, the preformed fluorine enriched surface region reinforces the outer lattice through the formation of robust F-TM bonds, promoting the generation of a uniform and stable CEI layer, mitigating electrolyte decomposition and interfacial reactions. The optimized NFA-LRM delivers a high discharge capacity of 318.7 mAh g-1 at 0.1 C, with reversible capacities of 140.6 and 108.5 mAh g-1 at 5 C and 10 C, respectively, and retains 96.29% capacity after 250 cycles at 2 C. This work provides a bulk and surface synergistic strategy for high energy LRMs with stabilized oxygen chemistry and durable interfacial stability.