Developing Thermoregulatory Hydrogel Electrolyte to Overcome Thermal Runaway in Zinc‐Ion Batteries

Abstract Zinc‐ion batteries (ZIBs) that use water‐based electrolytes have attracted significant attention. However, under harsh conditions, extreme heat is accumulated inside ZIBs, which inevitably causes thermal runway risk. Therefore, the practical applications of rechargeable ZIBs are significantly limited because the internal heat accumulated by harsh conditions induces drastic bulges or even explosions. To overcome this limitation, a self‐adaptive thermoregulatory hydrogel electrolyte (TRHE) that integrates phase transition chains with endothermic effects into agarose backbones via hydrogen bonding interactions is reported. Under extreme conditions, TRHE can tolerate sudden thermal shock; thus, ZIBs can function properly for a period in environments (100 °C) owing to their thermally self‐regulating feature, which alleviates the thermal issues associated with batteries. The hydrogel network with uniform ion migration channels can accelerate ion transport and homogenize ion distribution to realize dendrite inhibition; in addition, other pressing concerns can be effectively resolved, including hydrogen evolution and Zn corrosion, which significantly contribute to the outstanding electrochemical performance. It is believed that the proposed TRHE will help in overcoming thermal runaway in ZIBs and in other aqueous batteries.