Abstract
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.
Highlights
Rechargeable aqueous batteries are an up-and-coming system for potential large-scale energy storage due to their high safety and low cost
The freezing process is an intricate rearrangement from orderless water to ordered ice, which is driven by forming extra hydrogen bonds (H-bonds)[16,17,18,19,20]
Despite the introduction of organics can suppress the freeze of water, it reduces the ionic conductivity of electrolyte (0.11 mS cm−1 at –50 °C) and restricts the lowest operation temperature of batteries up to –50 °C21
Summary
Rechargeable aqueous batteries are an up-and-coming system for potential large-scale energy storage due to their high safety and low cost. We report the breakage of original hydrogen-bond network in ZnCl2 solution by modulating electrolyte structure, and 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. The batteries based on the organic electrolyte with low-freezing-point solvent, such as liquefied CO2/fluoromethane gas[25], ethyl acetate[26], and perfluorinated ether[27], can reach the ultralow operation temperature of –60, –70 and –85 °C, respectively. We aim at ZnCl2-based aqueous electrolyte and explore the relationship among ZnCl2 concentration (CZnCl2 ), electrolyte structure (including H-bonds and ion interactions) and
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