Coupling Polar Terminal Designation and Double‐Network Structural Construction of Hydrogel Electrolyte for Boosting Dendrite‐Free Aqueous Zinc‐Ion Batteries

Abstract Aqueous zinc‐ion batteries (AZIBs) emerge as a highly promising energy storage device due to their cost‐effectiveness and inherent safety. However, the operating lifespan of AZIBs is significantly hindered by the mad growth of Zn dendrites and interfacial side reactions in the metallic Zn anode. To address these issues, a covalently crosslinked double‐network hydrogel (labeled as PVMES) is elaborately established by incorporating polyacrylamide and polyvinyl alcohol as well as terminalized with sulfonic acid groups, employed as the optimized quasi‐solid‐state electrolyte for AZIBs. The PVMES electrolyte with strengthened toughness enables to induce of uniform Zn 2 ⁺ deposition along the (002) crystal plane and inhibits the activity of water molecules through the synergistic effect of its homogeneous transmission channels and strongly polar groups, thereby effectively inhibiting dendrite growth and parasitic reactions. As a result, the Zn||PVMES||Zn symmetric cell exhibits exceptional long‐lifespan cycling stability exceeding 2050 h at 1 mA cm −2 /1 mAh cm −2 . The assembled Zn||PVMES||NVO full cell delivers a reversible specific capacity of 248 mA h g −1 at 5.0 A g −1 , with 89.8% of capacity retention over 500 cycles. This work provides a novel design paradigm for developing a highly stable hydrogel electrolyte to realize durable operation of a dendrite‐free Zn anode for AZIBs.