A Double-Network Hydrogel Electrolyte for a Flexible Zn-MnO₂ Battery with a Wide Operating Temperature Range

The development of aqueous zinc-ion batteries (AZIBs) has attracted attention owing to their excellent safety and electrochemical performances; however, the practical application is still limited by the poor temperature tolerance of water. Therefore, hydrogel electrolytes with superb conductivity and mechanical properties over a wide temperature range are highly desirable to assemble an all-climate AZIB. Herein, a hydrogel electrolyte with excellent comprehensive performance was successfully fabricated by constructing double-network (DN) hydrogels and introducing a certain concentration of salt solution. Surprisingly, the electrolyte exhibited an impressive ionic conductivity (23 mS cm^-1 at -30 °C) and tensile strength (107 KPa at -60 °C) due to the interactions of internal networks. The prepared Zn-MnO₂ battery showed excellent rate performance and specific capacity (251.9 mAh g^-1 at room temperature) within a wide operating temperature range (-30 to 60 °C). Remarkably, the battery could work normally even under 85% compressive strain or 135° bending. It is believed that the flexible Zn-MnO₂ battery with a wide operating temperature based on the DN hydrogel electrolyte holds enormous potential as a reliable power source for flexible wearable electronic devices.