Component Fluctuation Modulated Gelation Effect Enable Temperature Adaptability in Zinc‐Ion Batteries

Abstract The active H 2 O and slow ion kinetics behavior deteriorate the performance of aqueous zinc‐ion batteries at a wide temperature range, even in hydrogel electrolyte. Herein, a component fluctuation modulated gelation effect is applied to optimize Zn 2+ solvation structure, realizing a balance between H 2 O activity limitation and Zn 2+ kinetics retention. The as‐prepared hydrogel electrolyte via in situ copolymerization of [2‐(methacryloyloxy)ethyl] dimethyl‐(3‐sulfopropyl) and acrylamide in the electrolyte salt matrix facilitates stable overall performance at both normal and low temperatures. Theoretical calculations and experimental results attest that polymer functional groups exhibit a higher efficacy in substituting bound water in the Zn 2+ solvated shell with the polymer content increasement, thereby alleviating water‐associated parasitic reactions. Furthermore, the hydrogel with abundant zwitterionic groups not only interacts with H 2 O to limit hydrolysis, but also constructs separated ionic migration channels to promote uniform and fast Zn 2+ transport. As a result, the hydrogel electrolytes promote stable Zn 2+ plating/stripping behaviors over 1050 h and 3000 h at 25 and −20 °C, respectively. The full batteries achieve a capacity retention of 98.8% over 2000 cycles at 25 °C and stably cycle for 600 times at −20 °C. This work yields novel insights into the development and design of hydrogel electrolytes.