Stretchable, Adhesive, Anti-Freezing Hydrogel Electrolytes with Dual-Functional Water Regulation Enabled by Amide Group–Salt–Water Interactions for All-Climate Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising candidates for next-generation energy storage due to their intrinsic safety and environmental compatibility. However, parasitic reactions induced by active water molecules in conventional aqueous electrolytes severely degrade electrochemical performance and cycling stability. Herein, a stretchable, adhesive, anti-freezing hydrogel electrolyte with dual-functional water regulation is synthesized via a one-pot radical polymerization strategy, where acetate (Ac − ) anions and hydrophilic amide (─CONH 2 ) groups on polyacrylamide (PAM) chains synergistically regulate water activity. This design disrupts water's intrinsic hydrogen bond network and suppresses interfacial side reactions, enabling stable AZIBs operation across a wide temperature range (−20 to 100 °C). Consequently, Zn||Cu cells employing PAM-Zn(Ac) 2 -4KAc (denoted PAM-ZnK4Ac) hydrogel electrolyte achieve an average Coulombic efficiency of 99.7% over 500 cycles, demonstrating outstanding reversibility. Meanwhile, Zn||polyaniline (PANI) cells retain 81.4% capacity after 1100 cycles at −20 °C and operate effectively up to 100 °C. This work establishes a facile yet effective strategy for preparing hydrogel electrolytes, advancing all-climate AZIBs toward extreme-environment energy storage and flexible electronics.