Chromate-Conversion-Induced Cr2O3-Rich Interphase for Dendrite-Free and Highly Reversible Zinc Metal Anodes

en This link goes to a English section zh This link goes to a Chinese section Aqueous zinc batteries hold great promise for large-scale energy storage, yet their practical application is hindered by dendrite growth and interfacial side reactions on the zinc anode. Inspired by the industrially mature chromate passivation technology, this work reports an in situ construction of a chromium-rich passivation layer (Zn@Cr) on zinc metal via a liquid-solid interface reaction between zinc foil and sodium chromate solution. Systematic characterization reveals that the passivation layer is composed of crystalline Cr 2 O 3 with a dense and uniform structure. Electrochemical tests demonstrate that the optimized Zn@Cr-2 anode enables over 1400 h of stable cycling in symmetric cells (1 mA cm −2 , 1 mAh cm −2 ) and achieves an average Coulombic efficiency of 99.37% in Zn‖Cu half-cells. When coupled with a MnO 2 cathode, the Zn@Cr-2||MnO 2 full cell delivers an initial capacity of 218.8 mAh g −1 at 1 A g −1 and retains 179.1 mAh g −1 after 950 cycles, exhibiting excellent rate capability and long-term cycling stability. Further mechanistic analysis reveals that the chromium-rich layer functions both as an “interfacial shield” and a “deposition guide”: it suppresses hydrogen evolution and corrosion side reactions while inducing preferential Zn deposition along the (002) plane, thereby enabling uniform and dense zinc nucleation and growth. This study extends conventional metal surface treatment technology to the protection of battery anodes, offering a new strategy for interfacial design in high-performance aqueous zinc batteries that combines industrial feasibility with academic significance. 摘要 en This link goes to a English section zh This link goes to a Chinese section 水系锌电池在大规模储能领域具有广阔前景 , 但其实际应用受到锌负极枝晶生长和界面副反应的制约。受工业上成熟的铬酸盐钝化技术启发 , 本研究通过锌箔与铬酸钠溶液的液-固界面反应 , 在金属锌上原位构建了富铬钝化层 ( Zn@Cr ) 。系统表征结果表明 , 该钝化层由结晶态 Cr 2 O 3 组成 , 结构致密均匀。电化学测试显示 , 优化后的Zn@Cr-2负极在对称电池中 (1 mA cm −2 , 1 mAh cm −2 ) 可实现超过1400小时的稳定循环 , 在Zn‖Cu半电池中平均库仑效率达99.37%。与MnO₂正极匹配时 , Zn@Cr-2||MnO₂全电池在1 A g −1 电流密度下的初始容量为218.8 mAh g −1 , 经过950次循环后仍保持179.1 mAh g −1 , 展现出优异的倍率性能和长期循环稳定性。进一步机理分析表明 , 该富铬层既起到“界面防护盾”的作用 , 又具有“沉积导向”功能 : 一方面抑制析氢和腐蚀等副反应 , 另一方面诱导锌沿(002)晶面优先沉积 , 从而实现均匀致密的锌成核与生长。本研究将传统金属表面处理技术拓展至电池负极保护领域 , 为兼具工业可行性与学术意义的高性能水系锌电池界面设计提供了新策略。