Lithium-rich transition metal oxide (Li_1+XM_1−XO₂) cathodes have high energy density above 900 Wh kg⁻¹ due to hybrid anion- and cation-redox (HACR) contributions, but critical issues such as oxygen release and voltage decay during cycling have prevented their application for years. Here we show that a molten molybdate-assisted LiO extraction at 700 °C creates lattice-coherent but depth (r)-dependent Li_1+X(r)M_1−X(r)O₂ particles with a Li-rich (X ≈ 0.2) interior, a Li-poor (X ≈ −0.05) surface and a continuous gradient in between. The gradient Li-rich single crystals eliminate the oxygen release to the electrolyte and, importantly, still allow stable oxygen redox contributions within. Both the metal valence states and the crystal structure are well maintained during cycling. The gradient HACR cathode displays a specific density of 843 Wh kg⁻¹ after 200 cycles at 0.2C and 808 Wh kg⁻¹ after 100 cycles at 1C, with very little oxygen release and consumption of electrolyte. This high-temperature immunization treatment can be generalized to leach other elements to avoid unexpected surface reactions in batteries.

富锂过渡金属氧化物（Li _{1+ X} M _{1- X} O ₂）阴极由于阴离子和阳离子-氧化还原（HACR）的混合作用而具有900 Wh kg ^-1以上的高能量密度，但存在诸如氧气释放等关键问题以及循环期间的电压衰减已阻止了其应用多年。在这里，我们显示了在700°C的熔融钼酸盐辅助LiO萃取过程中产生的晶格相干但深度（r）依赖的Li _{1+ X（r）} M _{1- X（r）} O ₂颗粒具有富Li（X  ≈0.2）内部，锂贫（X  ≈-0.05）表面和之间的连续梯度。梯度富锂单晶消除了氧气释放到电解质中的现象，重要的是，仍然允许其中存在稳定的氧气氧化还原贡献。在循环期间，金属价态和晶体结构都得到很好的维持。梯度HACR阴极在0.2C下200次循环后显示843 Wh kg ^-1的比重，在1C下100次循环后显示808 Wh kg ^-1的比重，几乎没有氧气释放和电解质消耗。可以将这种高温免疫处理普遍化以浸出其他元素，以避免电池中意外的表面反应。