The high activity of water in aqueous electrolyte causes drastic side reactions on the Zn anodes, severely limiting the electrochemical performance of aqueous zinc metal batteries (AZMBs) under extreme conditions. Herein, levulinic acid is developed as the hydrated deep eutectic solvent (DES), to build a novel non‐flammable and cost‐effective ZnSO4‐based eutectic electrolyte with triple regulation of water molecules behavior, enabling highly stable AZMBs over a wide temperature. In situ experiments, molecular dynamics simulations, and spectroscopy analysis jointly reveal that the DES is capable of comprehensively lowering the water activity by simultaneously controlling the behavior of the free, solvated, and interfacial water molecules within the eutectic electrolyte system. Consequently, the Zn anodes exhibit ultralong cycling stability (4500 h at 1 mA cm−2/1 mA h cm−2), decent Coulombic efficiency of 99.39%, and excellent temperature tolerance (−20–50 °C). Notably, the designed 2.0 Ah Zn//VOX pouch cell exhibits a recorded actual energy density of 37.46 Wh Kg−1 and 95.38 Wh L−1 at the whole cell level, with a remarkable capacity retention of 81.01% after 150 cycles, demonstrating the potential for scale‐up into real AZMBs. This work provides an in‐depth understanding of the correlation between the water molecule behavior and electrochemical properties of AZMBs.

中文翻译：

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水分子行为的三重调节，通过一种新型高性价比的共晶电解质，在水性锌金属电池中实现高稳定性和宽温度耐受性


水系电解质中的高活性会在 Zn 负极上引起剧烈的副反应，严重限制了水系锌金属电池 （AZMB） 在极端条件下的电化学性能。在此，乙酰丙酸被开发为水合共熔溶剂 （DES），以构建一种新型不易燃且具有成本效益的基于 ZnSO4 的共晶电解质，具有水分子行为的三重调节，可在宽温度下实现高度稳定的 AZMB。原位实验、分子动力学模拟和光谱分析共同表明，DES 能够通过同时控制共晶电解质系统内游离、溶剂化和界面水分子的行为来全面降低水活度。因此，Zn 负极表现出超长循环稳定性（在 1 mA cm-2/1 mA h cm-2 下为 4500 小时）、99.39% 的良好库仑效率和出色的耐温性 （-20-50 °C）。值得注意的是，设计的 2.0 Ah Zn//VOX 软包电池在整个电池水平上表现出 37.46 Wh Kg-1 和 95.38 Wh L-1 的实际能量密度，在 150 次循环后具有 81.01% 的显着容量保持率，展示了放大到真正的 AZMB 的潜力。这项工作提供了对 AZMBs 水分子行为和电化学性质之间相关性的深入理解。