An initial crystalline phase can transform into another phases as cations are electrochemically inserted into its lattice. Precise identification of phase evolution at an atomic level during transformation is thus the very first step to comprehensively understand the cation insertion behavior and subsequently achieve much higher storage capacity in rechargeable cells, although it is sometimes challenging. By intensively using atomic-column-resolved scanning transmission electron microscopy, we directly visualize the simultaneous intercalation of both H₂O and Zn during discharge of Zn ions into a V₂O₅ cathode with an aqueous electrolyte. In particular, when further Zn insertion proceeds, multiple intermediate phases, which are not identified by a macroscopic powder diffraction method, are clearly imaged at an atomic scale, showing structurally topotactic correlation between the phases. The findings in this work suggest that smooth multiphase evolution with a low transition barrier is significantly related to the high capacity of oxide cathodes for aqueous rechargeable cells, where the crystal structure of cathode materials after discharge differs from the initial crystalline state in general.

当阳离子以电化学方式插入其晶格时，初始晶相可以转变为另一相。因此，在转变过程中在原子水平上精确识别相演变是全面了解阳离子插入行为并随后在可充电电池中实现更高存储容量的第一步，尽管有时具有挑战性。通过大量使用原子柱分辨扫描透射电子显微镜，我们直接可视化了 H ₂ O 和 Zn 在 Zn 离子放电到 V ₂ O _{5 中}的同时嵌入带电解质水溶液的阴极。特别是，当进一步插入 Zn 时，宏观粉末衍射方法无法识别的多个中间相在原子尺度上清晰成像，显示出相之间的结构拓扑相关性。这项工作的发现表明，具有低过渡势垒的平滑多相演化与用于水性可充电电池的氧化物阴极的高容量显着相关，其中放电后阴极材料的晶体结构与一般的初始晶态不同。