Highly efficient lithium-ion exchange membrane water electrolysis

Abstract

H-2 is a clean energy source for solving critical energy issues; hence, water electrolysis systems are needed for the storage of H-2 produced from renewable energy sources. In this study, we propose an alkaline-based water electrolysis system equipped with Li-ion exchange membranes fabricated with various weight ratios of polyvinyl alcohol (PVA) and Nafion. The physical (electrolyte uptake, thickness change, and mechanical strength), chemical (functional group and weight loss), and electrochemical (ionic conductivity and exchange capacity) properties of the polymer membranes are characterized. The LEMWE equipped with a polymer membrane containing an optimum amount of PVA exhibited a three-fold high current density of 1.65 A . cm(-2) at 1.7 V, owing to Li+ ion-based transporting mechanism, compared to the conventional alkaline water electrolysis. However, some issues of the LEMWE remain to enable its commercialization and use as an alternative to alkaline-based water electrolysis.