Synergistic vehicular-grotthuss conduction in double-network hydrogel electrolytes for zinc dendrite suppression in zinc-air batteries

The increasing demand for durable and high-performance energy storage systems, particularly for flexible and extreme-environment applications, drives innovation in solid-state electrolytes. Zinc-air batteries (ZABs) offer high energy density and intrinsic safety yet suffer from zinc dendrite growth and interfacial degradation in alkaline environments. Zinc dendrite growth remains a critical barrier for zinc-air batteries. Herein, we develop a double-network hydrogel electrolyte integrating bacterial cellulose (BC)-reinforced polyacrylamide (PAM) for mechanical robustness and quaternized Poly[3-(Methacryloylamino) propyl] trimethylammonium chloride (PMPTC) for ion conduction. The BC nanofibers form a percolating hydrogen-bond network that enables efficient proton hopping (Grotthuss mechanism), while the quaternary ammonium groups of PMPTC create continuous hydrophilic channels for vehicular ion transport. This unique combination enables synergistic Vehicular-Grotthuss conduction, achieving ultra-high ionic conductivity of 269.47 mS·cm −1 . Additionally, the polarized functional groups in both components help guide zincate ions (Zn (OH) 4 2− ) toward stable (002) plane deposition, effectively suppressing dendrite formation in ZABs. This design achieves exceptional water retention and enables ZABs operating over a wide temperature range. They exhibit a peak power density of 89.76 mW·cm −2 at room temperature, along with extended cycling stability. Multi-scale simulations confirm homogenized ion flux for uniform plating. This work establishes a paradigm for dendrite-suppressed, temperature-resilient zinc-air batteries.