物理化学学报

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分子级解析溶解-沉淀级联反应实现水系锌电池商用五氧化二钒正极的界面稳定

孙荣坤1,3, 胡馨怡1, 董锦洋2, 彭佳乐1, 石义乾1, 李萧阳1, 焦超群3, 冯贵涛1, 康晓红1   

  1. 1 北京交通大学物理科学与工程学院，北京 100044;
    2 北京理工大学材料学院，环境科学与工程北京市重点实验室，北京 100081;
    3 北京交通大学电气工程学院，北京 100044
  • 收稿日期:2026-06-07 修回日期:2026-07-13 录用日期:2026-08-27
  • 通讯作者: 董锦洋, 冯贵涛, 康晓红Jinyang Dong, Guitao Feng, Xiaohong Kang E-mail:jydong2023@163.com;gtfeng@bjtu.edu.cn;xhkang@bjtu.edu.cn

Molecular-level identification of the dissolution-precipitation cascade enables interfacial stabilization of commercial V2O5 cathodes in aqueous zinc batteries

Rongkun Sun1,3, Xinyi Hu1, Jinyang Dong2, Jiale Peng1, Yiqian Shi1, Xiaoyang Li1, Chaoqun Jiao3, Guitao Feng1, Xiaohong Kang1   

  1. 1 School of Physical Science and Engineering, Beijing Jiaotong University, Beijing 100044, China;
    2 School of Materials Science and Engineering, Beijing Key Laboratory of Environmental Science and Engineering, Beijing Institute of Technology, Beijing 100081, China;
    3 School of Electrical Engineering, Beijing Jiaotong University, Beijing 100044, China
  • Received:2026-06-07 Revised:2026-07-13 Accepted:2026-08-27

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摘要： 水系锌离子电池(AZIBs)因其高安全性和低成本而受到广泛关注。然而，由钒溶解和界面OH−积累引起的五氧化二钒(V2O5)正极向非活性副产物的不可逆相变，仍是阻碍其实际应用的关键挑战。结合原位监测与拆解分析，追踪了这一失效机制背后的界面化学过程。实验与理论分析表明，界面OH−的积累导致局部pH值严重升高，从而引发副产物的加速沉淀以及伴随的钒氧化溶解。基于这一机制见解，我们引入了葡萄糖酸钠作为电解液添加剂，而非对本体正极材料进行改性。密度泛函理论(DFT)计算证实，葡萄糖酸根阴离子优先吸附在V2O5表面，构建了高度竞争性的疏水钝化层。更重要的是，该添加剂在界面处形成了一个动态的酸碱缓冲体系，直接中和了局部积累的OH−，从而彻底抑制了剧烈的pH波动。通过将这种pH缓冲、表面钝化和Zn2+络合相结合，V2O5的不可逆相变被成功遏制。因此，Zn||V2O5电池在0.2 A∙g−1的电流密度下实现了290 mAh∙g−1的峰值比容量，且在500次循环后容量保持率达82%，同时保持完好的V2O5骨架确保了优异的倍率性能。最终，通过隔离这一分子级的“溶解-沉淀”触发机制，建立了一种高度普适的设计范式——将界面缓冲、多位点吸附和离子络合融为一体——用以稳定水系电池中的转化型正极。

关键词: 水系锌离子电池, 五氧化二钒正极, 相转变, 电解液添加剂, 界面演化

Abstract: Aqueous zinc-ion batteries (AZIBs) are attracting widespread attention due to their high safety and low cost. However, the irreversible phase transformation of the V2O5 cathode into inactive by-products, driven by vanadium dissolution and the accumulation of interfacial OH−, remains a key challenge hindering their practical application. Coupling in situ monitoring with post-mortem analysis, we trace the interfacial chemical processes underlying this failure mechanism. Experimental and theoretical analyses reveal that the accumulation of interfacial OH− leads to a severe local increase in pH, thereby triggering the accelerated precipitation of by-products and the concurrent oxidative dissolution of vanadium. Guided by this mechanistic insight, we introduce sodium gluconate as an electrolyte additive rather than modifying the bulk cathode material. Density functional theory (DFT) calculations confirm that the gluconate anion preferentially adsorbs onto the V2O5 surface, establishing a highly competitive hydrophobic passivation layer. More importantly, this additive forms a dynamic acid-base buffering system at the interface that directly neutralizes locally accumulated OH−, completely suppressing drastic pH fluctuations. By coupling this pH buffering with surface passivation and Zn2+ complexation, the irreversible phase transition of V2O5 is arrested. Consequently, the Zn||V2O5 battery delivers a peak specific capacity of 290 mAh∙g−1 at 0.2 A∙g−1, with 82% capacity retention after 500 cycles, while the preserved V2O5 framework ensures excellent rate performance. Ultimately, isolating this molecular-level dissolution-precipitation trigger establishes a highly general design paradigm—integrating interfacial buffering, multi-site adsorption, and ion complexation—for stabilizing conversion-type cathodes in aqueous batteries.

Key words: Aqueous zinc-ion battery, Vanadium pentoxide cathode, Phase transformation, Electrolyte additive, Interfacial evolution