Cation-disordered Li-excess oxides/oxyfluorides have opened the door for designing alternative, high energy cathodes. However, achieving long cycle life and high rate capability represents a major challenge for disordered rocksalt cathodes (DRX). Herein, we develop Li₂Mn_3/4Cr_1/4O₂F (LMCOF) DRX materials through a distinct redox mechanochemical method. The LMCOF contains trivalent Cr³⁺ and Mn³⁺, which allows for simultaneously accessing stable Mn/Cr dual redox at a narrow voltage window acceptable for conventional carbonate electrolytes. Coupled with the mitigated and reversible oxygen chemical changes, the LMCOF delivers high capacity, rate capability, as well as long cycle life upon extensive 1,000 cycles at various current densities. The multiscale synchrotron and neutron scattering, spectroscopic, and imaging analyses demonstrate that the capacity originates from the Mn/Cr dual redox with minimal contribution from oxygen redox, and that the good cycle life is attributed to the stable global crystal structure and local oxygen chemical environment.

阳离子无序的锂过量氧化物/氟氧化物为设计替代的高能阴极打开了大门。然而，对于无序的岩盐阴极（DRX）而言，实现长循环寿命和高倍率性能是一项重大挑战。在这里，我们通过独特的氧化还原机械化学方法开发了Li ₂ Mn _3/4 Cr _1/4 O ₂ F（LMCOF）DRX材料。LMCOF包含三价Cr ³⁺和Mn ³⁺，这允许在常规碳酸盐电解质可接受的狭窄电压范围内同时访问稳定的Mn / Cr双氧化还原。LMCOF与缓解和可逆的氧气化学变化相结合，在各种电流密度下进行了1000次循环后，具有高容量，高倍率能力以及长循环寿命。多尺度同步和中子散射，光谱和成像分析表明，容量源自Mn / Cr双氧化还原，而氧氧化还原的贡献最小，并且良好的循环寿命归因于稳定的整体晶体结构和局部氧化学环境。