Synergistic In Situ Mg Doping and Li2MnO3 Coating toward High-Performance Lithium-Rich Manganese-Based Cathodes

Lithium-rich, manganese-based layered oxides are among the most promising cathode materials for next-generation lithium-ion batteries (LIBs), offering high reversible capacity, elevated operating voltage, and cost-effectiveness compared to conventional cathodes. However, their practical application is hindered by irreversible lattice oxygen loss and structural degradation during cycling. In this work, Li1.2Mn0.54Ni0.13Co0.13O2 was modified via in situ Mg2+ doping and uniform Li2MnO3 surface coating to address these challenges. The dual-modified material was systematically investigated through theoretical analysis and validated experimentally using structural, morphological, and electrochemical characterization techniques. Electrochemical evaluations revealed that the synergistic effect of Mg2+ doping and Li2MnO3 coating significantly improved the material's performance, delivering a high discharge capacity of 193.9 mAh/g at 1C and an impressive capacity retention of 86.4% after 200 cycles. Additionally, the 52.73% reduction in voltage fade achieved through Mg2+ doping and Li2MnO3 coating further confirms the enhanced interfacial stability and significantly improved long-term cycling durability of the modified electrode.