Bio-inspired hyaluronic acid enhanced dual-network hydrogel electrolyte unlocks dendrite-free Zn deposition and exceptional cycling stability in flexible zinc ion batteries

Zinc-ion batteries (ZIBs) have attracted widespread attention and experienced rapid development due to their high theoretical capacity, suitable voltage, and abundant zinc resources. However, their widespread deployment faces challenges like zinc dendrite growth and harmful side reactions. Hydrogel electrolytes offer a potential solution, effectively suppressing these issues and enabling flexible, wearable ZIBs for next-generation electronics. Herein, we present a dual-crosslinked hydrogel electrolyte (HPM) fabricated by free-radical polymerization that integrates a physically crosslinked network of the natural biopolymer hyaluronic acid (HA) with a chemically crosslinked polyacrylamide (PAM) framework. HA enhances mechanical robustness and interfacial adhesion via its abundant carboxylate and hydroxyl groups, coordinates Zn 2+ to modulate the solvation sheath and direct uniform Zn deposition, thereby effectively suppressing dendrite growth. As a result, Zn//Zn symmetric cells employing HPM demonstrated exceptional long-term cycling stability (1700 h at 1 mA cm −2 /0.5 mAh cm −2 ). Furthermore, Zn//HPM//PANI@CC full cells exhibited outstanding specific capacity (132.3 mAh g −1 at 0.2 A g −1 ) and remarkable cycle life (75% capacity retention after 2000 cycles at 2 A g −1 ). The practical viability of this electrolyte is highlighted by a functional flexible pouch cell incorporating HPM that successfully powered an LED display. This innovative dual-crosslinked HPM electrolyte design provides a valuable strategy for advancing high-performance flexible energy storage systems and electronic devices.