Subzero-tolerant BNP/Gly/IL hydrogel electrolyte for high-performance flexible zinc-air batteries in extreme environments

Abstract Flexible zinc-air batteries (ZABs) are highly promising for next-generation wearable electronics, yet their practical application is severely hindered by the intrinsic limitations of conventional hydrogel electrolytes, including rapid water evaporation, low-temperature freezing, and severe interfacial side reactions. To address these challenges, we propose a “multi-solvent-ion network synergistic regulation” strategy to design a robust, highly conductive, and anti-freezing quasi-solid-state electrolyte, termed the BNP/Gly/IL hydrogel. By integrating glycerol (Gly) and an ionic liquid ([EMIM][TFSI]) into a polymer matrix, we successfully reconstruct the internal hydrogen-bond network and the Zn 2+ solvation sheath. This synergistic interplay fundamentally depresses the freezing point, endows the hydrogel with exceptional environmental water retention (94.4% after 48 hours), and thermodynamically suppresses water-induced parasitic reactions (e.g., hydrogen evolution and dendrite growth) at the zinc anode interface. Consequently, the optimized BNP/Gly/IL electrolyte delivers a superb ionic conductivity of 154.63 mS cm −1 at ambient temperature and maintains a remarkable 66.9 mS cm −1 even at -10°C. The assembled flexible ZABs demonstrate a peak power density of 63.9 mW cm −2 and an impressive specific capacity of 618.4 mAh g −1 . Furthermore, the devices exhibit outstanding mechanical flexibility and long-term cycling stability under extreme conditions, achieving 116 stable charge-discharge cycles at -10°C without interfacial failure. This work provides a deep mechanistic understanding of multi-component electrolyte design, paving a new avenue for all-weather, durable, flexible energy storage systems.