By virtue of their prominent advantages in terms of capacity and voltage output and cost, O3-type layered transition-metal oxides are considered promising cathode materials for sodium-ion batteries (SIBs). However, their unstable electrochemistry at high voltages due to complex multiphase evolution in the bulk structure and continuous degradation of the electrolyte-cathode interphase hampers their practical viability. Here, we reveal a dual-stabilization effect of the cation dopants on the evolution of the bulk structure and electrode-electrolyte interphase of a Li-substituted O3-type cathode upon Na (de)intercalation. The incorporation of Li into the transition-metal layer could mitigate the Jahn-Teller distortion of the Ni³⁺ ion and prevent the loss of active transition-metal ions so that the unfavorable high-voltage phase transition and the degradation of the electrolyte-cathode interphase are suppressed. As a result, the Li-incorporated cathode material displays a high reversible capacity with good high-voltage durability to facilitate its service in high-energy-density SIBs.

凭借其在容量，电压输出和成本方面的显着优势，O3型层状过渡金属氧化物被认为是有前途的钠离子电池（SIB）阴极材料。然而，由于整体结构中复杂的多相演化以及电解质-阴极间相的连续降解，它们在高电压下的电化学不稳定，从而影响了它们的实际可行性。在这里，我们揭示了阳离子掺杂剂对Na（脱）嵌入后Li取代的O3型阴极的本体结构和电极-电解质界面相演变的双重稳定作用。将Li掺入过渡金属层可减轻Ni ³⁺的Jahn-Teller畸变离子并防止活性过渡金属离子的损失，从而抑制了不利的高压相变和电解质-阴极间相的降解。结果，掺锂的正极材料显示出高的可逆容量和良好的高压耐久性，从而有助于其在高能量密度的SIB中的使用。