Improving unstable anionic redox of Li-rich layered oxide cathodes at high voltage by synergistic bulk and interface engineering

Lithium-rich manganese-based layered oxides (LRMO) are regarded as promising cathode materials for future energy storage applications owing to their exceptional specific capacity. However, their practical application is hindered by unstable anionic redox during cycles, which lead to lattice oxygen loss and transition metal ion migration. Herein, a Li 2 WO 4 surface coating along with bulk W doping the synergistic strategy is proposed and developed to solve these issues for Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode. This synergistic approach effectively shields reactive oxygen species against degradation by the electrolyte, suppressing interfacial side reactions and associated capacity decay. Theoretical calculations demonstrates that the synergistic strategy regulates both the antibonding (TM-O)* orbitals and O 2p nonbonding states in LRMO. This electronic structure modulation improves charge transfer reversibility and oxygen stability, effectively inhibiting structural degradation and undesirable side reactions. The optimized cathode maintained higher capacity retention of 93.1 % at 1C after 150 cycles in comparison to 74.9 % for the pristine LRMO. This method helps explain how bulk and surface modifications work together to stabilize oxygen redox in LRMO cathodes for lithium-ion batteries. • New cathode the 0.02W@LRMO was generated by W 6+ concentration gradient doping and Li₂WO₄ coating. • Doping-induced enlargement of the (003) interplanar spacing enhances the lithium-ion diffusion rate. • 0.02W@LRMO mitigates lattice oxygen instability and prevents irreversible oxygen release. • Stabilizing anionic redox inhibits TM dissolution, phase degradation, and electrolyte corrosion. • The electrochemical and structural stability of 0.02W@LRMO are greatly improved.