Li-rich or Ni-rich layered oxides are considered ideal cathode materials for high-energy Li-ion batteries (LIBs) owing to their high capacity (> 200 mAh g^–1) and low cost. However, both are suffering from severe structural instability upon high-voltage cycling (> 4.5 V). Here, “Li-rich Ni-rich” Li_1.08Ni_0.9Mn_0.1O₂ oxides with core-shell architecture are designed and synthesized to improve their high-voltage cyclability. These oxides are determined to be composed of a less reactive “Li-rich Mn-rich” shell and a high-capacity “Li-rich Ni-rich” core. As Li-ions gradually enter into the core-shell precursor during high-temperature lithiation reaction, the interdiffusion of elements across the interphase between the Mn-rich shell and the Ni-rich core successively occurs. Such thermally-driven atomic interdiffusion could lead to a thickness-controllable “Li-rich Mn-rich” shell, which can guarantee an exceptional structural reversibility for the layered “Li-rich Ni-rich” core upon long-term cycling. As a consequence, the optimized core-shell Li_1.08Ni_0.9Mn_0.1O₂ achieves a capacity retention of 96% at 0.1 C after 100 cycles in the voltage range of 2.7–4.6 V. These findings might open up a new avenue for rational design of advanced cathode materials for LIBs and beyond.

富锂或富镍层状氧化物被认为是高能锂离子电池 (LIB) 的理想阴极材料，因为它们具有高容量 (> 200 mAh g –1 ) 和^低成本。然而，两者在高压循环 (> 4.5 V) 时都存在严重的结构不稳定性。在这里，设计并合成了具有核壳结构的“富锂富镍”Li _1.08 Ni _0.9 Mn _0.1 O ₂氧化物，以提高其高压循环性能。这些氧化物被确定为由反应性较低的“富锂富锰”壳和高容量的“富锂富镍”核组成。随着锂离子在高温锂化反应过程中逐渐进入核壳前体，相互扩散富锰壳层和富镍核之间界面的元素相继发生。这种热驱动的原子相互扩散可以形成厚度可控的“富锂富锰”壳层，从而保证层状“富锂富镍”核在长期循环过程中具有出色的结构可逆性。因此，优化的核-壳 Li _1.08 Ni _0.9 Mn _0.1 O ₂在 2.7-4.6 V 的电压范围内经过 100 次循环后，在 0.1 C 下的容量保持率为 96%。这些发现可能为合理的研究开辟一条新途径LIB 及其他先进阴极材料的设计。