Stabilizing Anionic Redox in Ni‐Rich Li‐Rich Cathodes through Ordered Superstructure

Abstract Li‐rich layered oxides with reversible anionic redox offer exceptional capacity but suffer from high‐voltage instability and oxygen loss at potentials exceeding 4.5 V. Here, a breakthrough in stabilizing oxygen redox is demonstrated through the design of a novel Ni‐based Li‐rich cathode material, Li _1.2 Ni _0.708 Mn _0.092 O ₂ , synthesized under low‐temperature atmospheric conditions. Structural characterization reveals an ordered superstructure phase that significantly enhances transition metal‐oxygen covalency, lowering the oxygen redox activation potential by 100 mV compared to conventional Mn‐based Li‐rich cathodes. The material delivers a high reversible capacity of 260 mAh g ⁻¹ with 80% capacity retention after 400 cycles, attributed to the synergistic stabilization of cationic (Ni ³⁺ /Ni ⁴⁺ ) and anionic (O ²⁻ /O ⁿ⁻ ) redox couples. The unique structural design mitigates lattice strain during cycling, as evidenced by minimal c‐axis contraction (<1.08%) compared to conventional Ni‐rich cathodes. This work establishes a new materials design principle for high‐capacity Li‐rich cathodes by engineering ordered superstructures that simultaneously enable low‐voltage anionic redox and exceptional cycling stability, paving the way for next‐generation high‐energy lithium‐ion batteries.