Dual‐Function Surfactant‐Modified Electrolyte for Enhanced Calendar and Cycle Life of Aqueous Zinc Batteries ^†

Comprehensive Summary Deploying aqueous Zn batteries as next‐generation energy storage systems requires simultaneous improvements in calendar and cycle life, which remain hindered by side reactions such as corrosion and dendrite formation. While recent studies have enhanced cycling stability to some degree, they have largely overlooked calendar life and rarely provided quantified insights into corrosion‐induced capacity loss. In this work, we introduce the nonionic surfactant fatty alcohol polyoxyethylene ether (AEO) into a Zn(OTf) 2 ‐based electrolyte to improve calendar and cycle life by inhibiting Zn corrosion and optimizing Zn deposition homogeneity. Owing to its amphiphilic molecular structure, AEO forms a zinc‐philic and hydrophobic adsorption layer and spontaneously regulates Zn 2+ solvation/desolvation structure through enhanced interactions with lone pair electrons, mediating corrosion pathways by limiting solvated and interfacial water molecules. Therefore, the AEO electrolyte suppresses corrosion current by 74.9% and Coulombic efficiency loss by 18.48% after 24‐hour aging in a Zn||Cu configuration. Furthermore, a Zn‐powder‐based full cell with a low negative to positive (N/P) ratio of 2.5 achieves a high capacity retention of 83.37% over 100 cycles, including 20 times of 24‐hour intermittent aging. This work sheds light on the mechanism of the surfactant‐modified electrolyte and offers a scalable approach for practical long‐life aqueous Zn batteries.