Reaction modifier system enable double-network hydrogel electrolyte for flexible zinc-air batteries with tolerance to extreme cold conditions

The zinc-air battery (ZAB) is a promising candidate for powering wearable electronic devices. Unfortunately, traditional ZAB hydrogel electrolytes dehydrate at room temperature and freeze at extreme cold temperatures, limiting their working life and ability to adapt to the extreme cold polar environment. Herein, the fabrication of alkaline double-network hydrogel electrolytes is made simple using in-situ polymerization of acrylamide (AM) and cellulose nanofibers (CNF), followed by immersion in a solution containing KOH and KI reaction modifier. The anti-dehydration and anti-freezing properties of the prepared hydrogel electrolyte are greatly improved. Furthermore, by altering the conventional discharge/charge reaction paths, the addition of KI significantly improves the energy efficiency of ZABs. The ZAB based on the hydrogel electrolyte not only has excellent discharge/charge performance and cycling life at room temperature, but it can also operate in extremely cold temperatures (-40 °C). The ZABs are connected to power a variety of electronic devices, indicating that they could be used as wearable energy storage devices.