Self‐Healing Ionogel with Unprecedented High Gel‐Sol Transition Temperature Enables Self‐Healing Zinc‐Air Battery Operation at 100 °C

Abstract

Existing zinc‐air batteries (ZABs) suffer from limited cycle lives and instability at temperatures exceeding 60 °C, severely hindering their high‐temperature application. Herein, a self‐healing ionogel with an exceptionally high gel‐sol transition temperature (Tgel‐sol) is prepared, enabling stable ZAB operation at 100 °C. This ionogel, termed UGTS, is synthesized by copolymerizing 2‐(2‐benzoylhydrazine‐1‐carboxamido)ethyl acrylate with poly(ethylene glycol) monomethyl ether acrylate and incorporating Zn(BF4)2/1‐ethyl‐3‐methylimidazolium tetrafluoroborate electrolyte. The UGTS ionogel exhibits non‐volatility, a Tgel‐sol of 187 °C, high decomposition voltages at elevated temperatures, and the ability to suppress zinc dendrite growth and by‐product formation under high‐temperature conditions. Moreover, this ionogel exhibits a rapid, efficient, and repeatable room‐temperature self‐healing capability. These attributes are ascribed to its multiple‐hydrogen‐bond‐induced phase‐separated structure, which provides excellent high‐temperature thermal stability and dynamics. At 100 °C, the UGTS ionogel‐based ZAB achieves a 76 h cycle life and can reliably power a digital watch for over 6 days, a performance unattainable by previous ZABs. Moreover, after being severed, the electrochemical performance of this battery is fully restored within 3 s at room temperature. This work provides a novel strategy for developing high‐performance self‐healing ZABs for extreme temperature applications, addressing the critical challenges of thermal stability and self‐healing in next‐generation energy storage devices.