Hydrogen-bonding network tailoring via EG-based DES/CMC-Na synergy enables longevous and dendrite-free flexible aqueous zinc-ion batteries

To overcome critical challenges in flexible aqueous zinc-ion batteries (AZIBs)—specifically zinc dendrite proliferation, recurrent side reactions, and electrolyte mechanical-electrochemical incompatibility—we engineered a hydrogel electrolyte (PZEC). Synthesized in one step, PZEC integrates polyacrylamide (PAM)/ZnSO₄ with synergistic enhancements from ethylene glycol (EG)-based deep eutectic solvent (DES) and sodium carboxymethyl cellulose (CMC Na). A synergistic multi-component modification strategy reconstructing the hydrogen bond network yielded concurrent, major gains in mechanical strength and electrochemical stability. Hydrogen bond deconvolution analysis revealed a 3.1 % increase in strong hydrogen bonds within PZEC, accompanied by a significant reduction in the phase transition temperature to −29.46 °C, indicative of enhanced bound water confinement and low-temperature adaptability. PZEC manifests excellent mechanical properties (90 kPa fracture stress, 1280 % elongation) while attaining high ionic conductivity (29.26 mS·cm −1 ) and zinc ion transference number (0.63) via zinc solvation sheath compression and guided ion transport. The Zn//Zn symmetric battery exhibited exceptional cycling endurance, operating for 700 h at 5 mA·cm −2 and over 2000 h at 0.5 mA·cm −2 . Notably, PZEC maintained superior rate performance and cycling stability at 0 °C, retaining high reversible capacity and near-100 % coulombic efficiency (CE) even under high-rate conditions. Consequently, this work outlines a new methodology for high-performance flexible AZIBs and delivers significant insights for hydrogen bond-functionalized electrolyte engineering.