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

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 degrees 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 Zn2+ transport pathways, boosting ionic conductivity. Synergistically, Thy and SPE reconstruct the Zn2+ 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 degrees C and 820 h at 60 degrees C, 1 mA cm-2). The Zn||VO2 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.