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Abstract Constructing ionic conductive hydrogels with diversified properties is crucial for portable zinc‐ion hybrid supercapacitors (ZHSCs). Herein, a freeze‐tolerant hydrogel electrolyte (AF PVA‐CMC/Zn(CF 3 SO 3 ) 2 ) is developed by forming a semi‐interpenetrating anti‐freezing polyvinyl alcohol‐carboxymethyl cellulose (AF PVA‐CMC) network filled with the ethylene glycol (EG)‐containing Zn(CF 3 SO 3 ) 2 aqueous solution. The semi‐interpenetrating AF PVA‐CMC/Zn(CF 3 SO 3 ) 2 possesses enhanced mechanical properties, realizes the uniform zinc deposition, and impedes the dendrite growth. Notably, the interaction between PVA and EG suppresses the ice crystal formation and prevents freezing at −20 °C. Due to these advantages, the designed hydrogel owns high ionic conductivity of 1.73/0.75 S m −1 at 20/−20 °C with excellent tensile/compression strength at 20 °C. Impressively, the flexible AF quasi‐solid‐state ZHSC employing the hydrogel electrolyte achieves a superior energy density at 20/−20 °C (87.9/60.7 Wh kg −1 ). It maintains nearly 84.8% of the initial capacity after 10 000 cycles and a low self‐discharge rate (1.77 mV h −1 ) at 20 °C, together with great tolerance to corrosion. Moreover, this device demonstrates a stable electrochemical performance at −20 °C under deformation. The obtained results provide valuable insights for constructing durable hydrogel electrolytes in cold environments.
Zhu et al. (Thu,) studied this question.