A study of alkaline gel polymer electrolytes for rechargeable zinc-air batteries

摘要

In this report, hydrated hydrogels are investigated for application in rechargeable zinc-air batteries (ZABs) based on their ionic conductivities, chemical stability, electrochemical windows and mechanical properties. Three different hydrogel networks, i.e., poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA) and poly(4-vinylbenzenesulfo nate-co-[3-( methacryloylamino )p ropyl]trimethylammonium chloride) ( PAM), were chosen based on their chemical composition and different charged functional groups in the polymer network. Since the hydrogel network affects electrolyte uptake, which in turn may influence conductivity, understanding the correlation between hydrogel species and ionic conductivity provides insight into designing an appropriate gel polymer electrolyte (GPE) for ZABs. The relationship between ionic conductivity, water uptake and temperature are discussed. In ZAB cycling tests, although GPEs have a higher bulk resistance than aqueous electrolytes, they have lower interfacial and charge transfer resistances. The total resistance values for PVA and PAA, with 6 M KOH, vary from 4 to 6 Omega, which are lower than the values for KOH solution (similar to 11 Omega) and PAM with 6 M KOH (similar to 14 Omega). As such, this study demonstrates that GPEs show considerable promise for use as electrolytes in ZABs. (C) 2019 Elsevier Ltd. All rights reserved.