Ternary Gel Electrolyte Enabling Wide‐Temperature and High‐Rate Performance in Aqueous Zinc‐Ion Batteries

Abstract Aqueous zinc‐ion batteries (AZIBs) offer significant potential for grid‐scale energy storage due to their cost‐effectiveness, safety, and eco‐friendliness. However, interfacial instability and parasitic reactions under extreme temperatures (−20 to 60 °C) severely degrade their cyclability. To address these limitations, a ternary copolymer gel electrolyte (PAM‐T‐S) is developed through copolymerization of acrylamide (AM) with [2‐(methacryloyloxy)ethyl]dimethyl(3‐sulfopropyl)ammonium betaine (SPE) and thymine (Thy), forming a multidimensional crosslinked network. Thy immobilizes free water molecules to suppress electrolyte activity, while SPE establishes rapid Zn ²⁺ transport pathways, boosting ionic conductivity. Synergistically, Thy and SPE reconstruct the Zn ²⁺ solvation sheath and induce a hybrid organic–inorganic solid electrolyte interphase (SEI) via preferential adsorption and decomposition, effectively inhibiting dendrite growth and side reactions. Consequently, Zn||Zn symmetric cells with PAM‐T‐S achieve long lifespans of 3200 h at 1 mA cm ⁻² /1 mAh cm ⁻² and 1000 h at 20 mA cm ⁻² , along with exceptional wide‐temperature performance (3000 h at −20 °C and 820 h at 60 °C, 1 mA cm ⁻² ). The Zn||VO ₂ full cell retains 87.8% capacity after 2000 cycles at 5C, highlighting its high‐rate durability. This multifunctional hydrogel design advances AZIBs toward reliable operation across broad temperature ranges, providing a scalable strategy for next‐generation energy storage systems.