Hydrogel Electrolyte With Ultrahigh Water‐Locking Capability for Quasi‐Solid Zinc‐Ion Batteries with Extreme Environmental Safety

Abstract Aqueous zinc‐ion batteries (AZIBs) are considered promising energy storage devices because of the intrinsic safety, low cost, and environmental friendliness. However, the electrochemical performance of AZIBs is often hindered by side reactions occurring in electrolytes across different temperatures. Herein, this work investigates a quasi‐solid hydrogel electrolyte, named GPE‐EG with wide‐temperature adaptability by simple copolymerization [2‐(methacryloyloxy)ethyl] dimethyl(3‐sulfopropyl) (SBMA) and acrylamide (AM) with H 2 O and ethylene glycol (EG) as co‐solvents. The ion transport channels provided by SBMA and the regulation of electric field distribution on the zinc anode surface significantly enhance the cycling performance of AZIBs. Moreover, the ultrahigh water‐locking capability of GPE‐EG significantly improves the stability of electrolytes at both low and high temperatures. The symmetrical batteries exhibit stable cycling for over 1000 h (−20 °C), 1300 h (25 °C), and 300 h (65 °C), and the Zn||PANI full batteries with GPE‐EG electrolyte exhibit remarkable electrochemical performance across a range of temperatures. Moreover, the full batteries maintain stable performance even under simulated extreme environmental conditions with gradient temperature changes. This work presents a novel gel chemistry that regulates zinc behavior and water reactivity across temperature extremes, showing strong potential for AZIBs in harsh environments.