Flexible Wide-Temperature Zinc-Ion Battery Enabled by an Ethylene Glycol-Based Organohydrogel Electrolyte

Abstract

Electronic storage devices assembled from traditional hydrogel electrolytes (HEs) lose most of their capacity due to low-temperature effects and fail at high temperatures due to the water evaporation or accelerated hydrolysis of metal salt ions. Here, organohydrogel electrolytes (OHEs) are prepared by swelling freeze-dried hydrogels of poly(2-acrylamido-2-methylpropanesulfonic acid)/polyacrylamide in a binary solvent electrolyte of ethylene glycol and water (EG/H2O, water content 10% v/v) containing ZnCl2/NH4Cl. Owing to the synergistic solvation of ZnCl2, EG, and H2O, the OHE possesses a lower freezing point (<−60 °C) than the control HE. The flexible zinc||polyaniline (Zn||PANI) battery assembled by the OHE exhibits high rate performance (122.1 mA h/g, 5 A/g) and excellent cycle stability (81.5%, 4000 cycles) at room temperature. The Zn||PANI battery shows good electrochemical stability against the process of bending, heavy pressure, hammering, and soaking. More importantly, the battery has a wide operating temperature (−30 to 80 °C) with outstanding capacity retentions of 88.8% after 1500 cycles at −30 °C and 44.8% after 1000 cycles at 80 °C. Especially, the OHE can alleviate the problems of corrosion, zinc dendrite, and other side reactions of the zinc anode by generating an EG interphase on the surface of the zinc foil.