Recent progress in environment-adaptable hydrogel electrolytes for flexible energy storage devices

Hydrogels are considered as the most promising electrolyte candidates because of their high-water content and flexible mechanical properties, which fulfill the essential requirements for flexible energy storage devices. However, as the freezing or dehydration of hydrogels during environmental change, the electrochemical performance of those hydrogel-based energy storage devices is inevitably degradation, and even failure. Environment-adaptable hydrogels, which can withstand cold and arid environments without degradation of their properties, have been widely used in flexible energy storage devices. This review provides recent progress of environment-adaptable hydrogel electrolytes for flexible energy storage devices, ranging from environment-adaptable hydrogel electrolytes fabrication strategies to flexible energy storage devices applications, including zinc–air batteries (ZABs), zinc–ion batteries (ZIBs), and supercapacitors (SCs). Finally, challenges and future development directions are exposed.