Hydrogen-bond network engineering in deep eutectic solvent-infused hydrogel electrolyte for boosting dendritic-free aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) suffer from dendrite growth and interfacial side reactions caused by uncontrolled Zn2+ transport and solvation behavior. While hydrogel electrolytes improve safety by preventing leakage, their performance is often constrained by limited water regulation, slow ion transport, and weak mechanical properties. Here, we develop a deep eutectic solvent (DES)-modified polyacrylamide (PAM) hydrogel electrolyte (DEAM), where hydrogen-bond network engineering enables synergistic regulation of Zn2+ transport and deposition behavior. By incorporating a choline chloride/ethylene glycol-based DES into the polyacrylamide network, a dynamically reconfigurable hydrogen-bond network is formed. This simultaneously enhances structural stability, reconstructs the local water structure, and optimizes the Zn2+ solvation environment. The DEAM electrolyte exhibits high stretchability (fracture strain up to 1158%), enhanced toughness, and high ionic conductivity of 22.4 mS cm-1. It enables uniform Zn2+ flux, suppressing interfacial side reactions and promoting stable Zn nucleation and growth. Consequently, Zn||DEAM||Zn symmetric cells operate stably for over 1400 h at 1 mA cm-2/1 mAh cm-2. The assembled full cells achieve a high specific capacity of 256.9 mAh g-1 and maintain 82.8% capacity retention over 1500 cycles at 2 A g-1 with an average Coulombic efficiency up to 99.5%. Moreover, pouch cells remain operational even under cutting, puncturing, and bending. This work demonstrates that hydrogen-bond network engineering offers a promising route to regulate interfacial behavior in hydrogel electrolytes, advancing the design of stable and flexible AZIBs.