In Situ Magnetism Decoupling Gradient-Regulated Mn–O Interaction Mechanism on Stabilizing Li-Rich Cathodes

Lithium-rich layered oxides are promising high-capacity cathodes for lithium-ion batteries, but their commercialization is hindered by severe capacity loss and voltage decay. Herein, we develop a full concentration gradient Li-rich Mn-based layered oxide with gradually decreased Mn and increased Ni concentration from the center to the surface. The gradient material delivers exceptional cycling stability and rate capability, offering a high capacity of 216 mAh g –1 at 1 C and outstanding retention of 91.8% after 200 cycles at 2 C. To elucidate the underlying atomic-level interaction mechanism behind them, in situ magnetism characterization is employed and reveals that the gradient design effectively stabilizes Mn–O interaction and suppresses O–O dimer formation, alleviating irreversible anionic oxygen redox and undesirable structural degradation after long-term cycling. This work affords an effective gradient strategy to regulate the Mn–O interaction, opening up a new perspective for developing Li-rich Mn-based cathode materials.