Fabrication and Electrolyte Characterizations of Hydrogel Membranes Consisted of Cationic Network Polymers for Zinc-air Battery Applications (Supporting Information)

Rechargeable zinc-air batteries (r-ZABs) are excellent candidates for next-generation secondary batteries due to their high energy densities and safety; however, they have issues of electrolyte volatilization, leakage, and side reactions at the air electrode caused by zincate ([Zn(OH)4]2−) diffusion. A gel polymer electrolyte (GPE) consisting of a polystyrene-based densely crosslinked network structure bearing quaternary ammonium anion exchange groups at the crosslink points was developed. The GPE showed higher monovalent anion conductivity and lower divalent anion ([Zn(OH)4]2−) diffusion coefficient than a conventional anion exchange membrane and a porous separator due to the network structure with high ion exchange capacity (IEC) of the novel GPE. The charge-discharge r-ZAB test using the GPE demonstrated higher cycle stability than a liquid electrolyte due to enhanced ion conductivity and suppressed diffusion of [Zn(OH)4]2−, as well as sufficient mechanical toughness of the densely crosslinked network structure.