Processing of proton exchange membrane for vanadium redox flow battery

Abstract

Vanadium redox flow battery (VRFB) is a rechargeable energy storage device that converts chemical energy into electrical energy. Commercially. VRFB uses perfluorosulfonic acid. Nafion, as a proton exchange membrane (PEM) due to its high proton conductivity. However, Nafion is. an expensive and possesses high vanadium permeability. In order to reduce the limitation of membrane, the modified aromatic membranes, namely poly (ether ether ketone) and poly (phenylene ether ether sulfone), were developed to use as proton exchange membrane through a sulfonation process. The effect of degree of sulfonation on membrane properties as water uptake, proton conductivity, and vanadium permeability were investigated. The increasing degree of sulfonation induced increasing water uptake, proton conductivity, and vanadium permeability. The proton conductivity of sulfonated polymer was higher than Nafion that provided a higher vanadium permeability of sulfonated polymer than Nafion. Thus, the sulfonated polymer membrane fabricated in a VBRF is hopefully achieved to compromise between proton conductivity and vanadium permeability.