Nanostructured composite electrodes with multiple active phases offer extraordinary performance that can be harnessed in future batteries. However, it is difficult to disclose the complicated reaction pathways. In this work, NiO@CuO core-shell nanocomposites are prepared and used as anodes for lithium-ion batteries, with superior rate and stability performance compared with single-phase CuO and NiO. Using a combination of in situ and ex situ electron microscopy, a two-stage lithiation reaction pathway on NiO@CuO is identified, with CuO reduced to Cu₂O first and followed by the simultaneous reduction of both Cu₂O and NiO to metals, resolving the existing inconsistency in literature. Chemomechanical simulation further discloses the key role of the core-shell structure in high cycling stability of NiO@CuO, which decreases the probability of cracking during the discharge-charge process. This work provides new insights to explore lithiation mechanisms and kinetics in novel electrodes, which contribute to further development of various electrode materials.

具有多个活性相的纳米结构复合电极具有非凡的性能，可用于未来的电池。然而，很难揭示复杂的反应途径。在这项工作中，制备了NiO@CuO核壳纳米复合材料并将其用作锂离子电池的负极，与单相CuO和NiO相比，具有优异的倍率和稳定性能。结合原位和非原位电子显微镜，确定了NiO@CuO上的两阶段锂化反应途径，首先将CuO还原为Cu ₂ O，然后同时还原两种Cu ₂将 O 和 NiO 转化为金属，解决了文献中存在的不一致问题。化学力学模拟进一步揭示了核壳结构在 NiO@CuO 的高循环稳定性中的关键作用，这降低了放电-充电过程中开裂的可能性。这项工作为探索新型电极的锂化机制和动力学提供了新的见解，有助于进一步开发各种电极材料。