Sodium-ion batteries (SIBs) have demonstrated great application prospects in large-scale energy storage systems and low-speed electric vehicles due to the cost effectiveness and abundant resources. Layered transition-metal oxides are recognized as one of the most attractive sodium-ion storage cathode candidates by virtue of their high compositional diversity, environmental friendliness, ease of synthesis, and promising theoretical capacities. The practicability, however, is still limited by the fact that the energy densities of most Na-storage layered oxide cathodes solely using the conventional cationic redox are not comparable to those of the lithium-ion storage counterparts. Recently, the strategy of activating anionic redox (O²⁻/Oⁿ⁻) which is popular in Li-rich layered materials has been successfully applied in oxide cathodes of SIBs to promote the energy density to a new level. It is interesting to note that excess Na is not the prerequisite to induce anionic redox in sodium oxides, indicating a new mechanism underlying Na-ion materials. Herein, the latest advances on the anionic redox chemistry in layered oxide cathodes for SIBs, including the fundamental theories, triggering strategies, and applicable cathode materials, are comprehensively reviewed. Moreover, the challenges (mainly O₂ release) facing anionic redox are discussed, and the possible remedies are outlined for future developments toward a highly reversible oxygen usage. We believe that this review can provide a valuable guidance for the exploration of high-energy layered oxide cathode materials of SIBs.

钠离子电池（SIB）由于具有成本效益和丰富的资源，已在大型储能系统和低速电动汽车中显示出广阔的应用前景。层状过渡金属氧化物由于其高的组成多样性，环境友好性，易于合成和有希望的理论容量而被公认为是最有吸引力的钠离子存储阴极候选物之一。然而，实用性仍然受到以下事实的限制：大多数仅使用常规阳离子氧化还原的钠存储层状氧化物阴极的能量密度不能与锂离子存储对应物的能量密度相比。最近，激活氧化还原阴离子（O战略^2- / O ^{Ñ -}）在富锂层状材料中很流行）已成功地应用于SIBs的氧化物阴极中，以将能量密度提高到一个新的水平。有趣的是，过量的Na并不是在氧化钠中诱导阴离子氧化还原的先决条件，这表明Na离子材料具有新的机理。在此，对用于SIB的层状氧化物阴极中阴离子氧化还原化学的最新进展进行了全面回顾，包括基本理论，触发策略和适用的阴极材料。此外，挑战（主要是O ₂讨论了面对阴离子氧化还原的问题，并概述了针对高度可逆氧气使用的未来发展的可能补救措施。我们认为，这项综述可以为探索SIBs的高能层状氧化物阴极材料提供有价值的指导。