Thermal-gated polyanionic hydrogel films for stable and smart aqueous batteries

Achieving intelligent and efficient self-protection stands as the cornerstone for ensuring battery stability and safety. Herein a thermoresponsive polyanionic hydrogel film is proposed to enhance the stability and smart functionality of aqueous zinc-ion batteries. Distinguished by sulfonic acid groups, this hydrogel film facilitates uniform zinc deposition, yielding reversible zinc plating/stripping exceeding 1000 h, thereby guaranteeing sustained and dependable battery performance. Significantly, in the event of a thermal runaway scenario, the thermoresponsive hydrogel framework shrinks, impeding ion transport and ushering the battery into a self-protective state. This thermoresponsive behavior exhibits rapid and reversible attributes, manifesting within a matter of seconds. Overall, the thermal-gated polyanionic hydrogel film serves a dual role of bolstering battery stability and introducing intelligence. This proof-of-concept for zinc-ion batteries marks a step forward in the development of secure and intelligent batteries, promising not only advancements in consumer electronics but also applications in electric vehicles and large-scale energy storage.