Lattice oxygen release (LOR), which promotes surface structural degradation and electrolyte decomposition, is a major contributor to capacity fade and thermal runaway in layered oxide cathodes. Despite decades of research, it is still a great challenge to stabilize the lattice oxygen, especially in deeply delithiated cathodes. Here, we demonstrate an Li-enrichment strategy to revive lithium nickel oxide (LNO), a high-energy cathode (>900 Wh kg⁻¹) long plagued by poor cycle performance and thermal instability. In a slightly Li-enriched LNO (Li_1.04Ni_0.96O₂) prepared by a specially designed molten-salt synthesis, spatially resolved (operando) characterizations reveal intralayer Ni migration upon delithiation, and this leads to the formation of vacancy clusters to trap the electrochemically oxidized oxygen in the near-surface lattice. Thus, the detrimental effects of LOR are effectively suppressed. The Li-rich LNO cathode greatly outperforms the traditional Li-deficient LNO cathodes modified by conventional approaches such as doping and surface coating. Our findings open up new opportunities for building better batteries.

晶格氧释放 (LOR) 会促进表面结构降解和电解质分解，是层状氧化物正极容量衰减和热失控的主要原因。尽管进行了数十年的研究，但稳定晶格氧仍然是一个巨大的挑战，尤其是在深度脱锂的阴极中。在这里，我们展示了一种锂富集策略来恢复锂镍氧化物 (LNO)，这是一种长期受到循环性能差和热不稳定性困扰的高能正极 (>900 Wh kg ^{-1 )。}在稍微富锂的 LNO (Li _1.04 Ni _0.96 O ₂）通过特别设计的熔盐合成制备，空间分辨（操作）表征揭示了脱锂时层内Ni迁移，这导致空位簇的形成以将电化学氧化的氧捕获在近表面晶格中。因此，有效抑制了 LOR 的不利影响。富锂 LNO 正极的性能大大优于通过掺杂和表面涂层等常规方法改性的传统缺锂 LNO 正极。我们的发现为制造更好的电池开辟了新的机会。