Synergistic Effect of H‐bond Reconstruction and Interface Regulation for High‐Voltage Aqueous Energy Storage

Abstract Aqueous cells have gained widespread attention for their low‐cost and safety. However, the 1.23 V thermodynamic stability window of water severely limits their development and application. To solve this issue, this study proposes and demonstrates that regulators can enhance and protect water molecules through hydrogen bond reconstruction and assist in solid electrolyte interface generation. The expanded electrochemical window enables the construction of aqueous symmetric capacitors and Nb 18 W 16 O 93 ||LiMn 2 O 4 aqueous lithium‐ion batteries with voltages both up to 2.6 V, while exhibiting considerable Coulombic efficiency and high cycle stability. It is shown that efficient regulation of interaction and electrochemical window can also be achieved by a regulator alone, without relying on the effect of salt itself or the extreme reduction of water content. This not only provides a simple and effective way to develop aqueous cells, but also provides a new understanding for the research and utilization of H‐bonds and intermolecular interactions in water.