Modulating electrolyte structure for ultralow temperature aqueous zinc batteries

Rechargeable aqueous batteries are an up-and-coming system for potential large-scale energy storage due to their high safety and low cost. However, the freeze of aqueous electrolyte limits the low-temperature operation of such batteries. Here, we report the breakage of original hydrogen-bond network in ZnCl₂ solution by modulating electrolyte structure, and thus suppressing the freeze of water and depressing the solid-liquid transition temperature of the aqueous electrolyte from 0 to -114 °C. This ZnCl₂-based low-temperature electrolyte renders polyaniline||Zn batteries available to operate in an ultra-wide temperature range from -90 to +60 °C, which covers the earth surface temperature in record. Such polyaniline||Zn batteries are robust at -70 °C (84.9 mA h g^-1) and stable during over 2000 cycles with ~100% capacity retention. This work significantly provides an effective strategy to propel low-temperature aqueous batteries via tuning the electrolyte structure and widens the application range of temperature adaptation of aqueous batteries.