Permselectivity and Ionic Conductivity Study of Na+ and Br− Ions in Graphene Oxide-Based Membranes for Redox Flow Batteries

Abstract

Permselectivity of a membrane is central for the development of electrochemical energy storage devices with two redox couples, such as redox flow batteries (RFBs). In RFBs, Br3−/Br− couple is often used as a catholyte which can cross over to the anolyte, limiting the battery’s lifetime. Naturally, the development of permselective membranes is essential to the success of RFBs since state-of-the-art perfluorosulfonic acid (PFSA) is too costly. This study investigates membranes of graphene oxide (GO), polyvinylpyrrolidone (PVP), and imidazole (Im) as binder and linker, respectively. The GO membranes are compared to a standard PFSA membrane in terms of ionic conductivity (Na+) and permselectivity (exclusion of Br−). The ionic conduction is evaluated from electrochemical impedance spectroscopy and the permselectivity from two-compartment diffusion cells in a four-electrode system. Our findings suggest that the GO membranes reach conductivity and permselectivity comparable with standard PFSA membranes.

PVA–CS polymeric system conjugated with GO–ZnO–Ag2O ternary composite – a multifunctional nanocomposite for wound healing applications

“…4,17,18 While GO may not exhibit inherent electrical properties, it serves as a conduit for the transportation of conducting electrons and facilitates their swift transfer. 19–21 However, a notable drawback of GO sheets lies in the tendency for individual sheets to restack, primarily due to π–π stacking. This phenomenon could significantly diminish their mechanical, electrical and biological efficacy.…”