Flexible Wide-Temperature Zinc-Ion Battery Enabled by an Ethylene Glycol-Based Organohydrogel Electrolyte
Xilong Li, Hongyang Wang, Xiaoyi Sun, Juan Li, You‐Nian Liu
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.