Synergistic enhancement of cycling stability in Li-rich Mn-based layered oxide cathode materials via gas treatment and Mo6+ doping

Li-rich Mn-based layered oxide cathode materials (LRMs) are promising next-generation cathodes owing to their high discharge capacity (>250 mAh g −1 ), yet suffer from low initial Coulombic efficiency (ICE), poor rate performance, severe voltage decay and interfacial side reactions. To address these challenges, this study proposes a synergistic modification strategy integrating gas treatment and Mo 6+ doping. Through NH 3 treatment to pre-activate the Li 2 MnO 3 phase, the surface oxygen vacancy concentration is increased, improving the ICE. Simultaneously, the in situ induced layered-spinel heterostructure synergizes with strong Mo O bonds to stabilize the lattice oxygen on the material surface, suppress harmful phase transitions and interfacial side reactions, thereby delaying capacity and voltage decay during cycling. Mo 6+ doping expands the interlayer spacing and synergizes with the spinel phase (featuring 3D lithium-ion diffusion channels) to enhance the lithium-ion diffusion rate, optimizing rate performance. The modified material demonstrates significantly enhanced structural stability and effectively suppressed interfacial side reactions, achieving a mere 0.142 mAh g −1 capacity decay per cycle over 200 cycles at 1C, with discharge capacities of 188.8 and 152.8 mAh g −1 at 5C and 10C, respectively. This work proposes a synergistic modification strategy to enhance the structural stability and improve the electrochemical performance of LRMs.