Concentrated Hydrogel Electrolyte-Enabled Aqueous Rechargeable NiCo//Zn Battery Working from -20 to 50 °C.

Zn-based aqueous rechargeable batteries are promising in portable electronics because of their high voltage, low cost, etc. However, most conventional aqueous electrolytes are liable to freeze at low temperature and are incompatible with high ion concentrations, which hinders their application. Herein, we developed a sodium polyacrylate hydrogel (PANa) to superabsorb highly concentrated ions. Unprecedentedly, the hydrogel electrolyte can be stretched over ten times at -50 °C without any freezing. Therefore, the fabricated rechargeable NiCo//Zn battery worked well in a wide-temperature-range (-20 to 50 °C). This work creates many opportunities for the development and practical application of aqueous batteries.