Reshaping Zinc Plating/Stripping Behavior by Interfacial Water Bonding for High‐Utilization‐Rate Zinc Batteries

Aqueous zinc batteries have emerged as promising energy storage devices; however, severe parasitic reactions lead to the exacerbated production of Zn dendrites that decrease the utilization rate of Zn anodes. Decreasing the electrolyte content and regulating the water activity are efficient means to address these issues. Herein, this work shows that limiting the aqueous electrolyte and bonding water to bacterial cellulose (BC) can suppress side reactions and regulate stable Zn plating/stripping. This approach makes it possible to use less electrolyte and limited Zn foil. A symmetric Zn cell assembles with the hydrogel electrolyte with limited electrolyte (electrolyte‐to‐capacity ratio E/C = 1.0 g (Ah)−1) cycled stably at a current density of 6.5 mA cm−2 and achieved a capacity of 6.5 mA h cm−2 and depth of discharge of 85%. Full cells with the BC hydrogel electrolyte delivers a discharge capacity of 212 mA h cm−2 and shows a capacity retention of 83% after 1000 cycles at 5 A g−1. This work offers new fundamental insights into the effect of restricting water to reshape the Zn plating/stripping process and provides a route for designing novel hydrogel electrolytes to better stabilize and efficiently utilize the Zn anodes. A biodegradable bacterial cellulose (BC) hydrogel electrolyte is adopted to bond interface water molecules to suppress water activity and alleviate water‐induced side reactions in aqueous Zn‐ion batteries. Due to the interface water bonding effect, symmetric Zn cells assemble with the BC hydrogel electrolyte cycle stably and deliver a high utilization rate (>85%) of Zn anode under harsh test conditions.