Composite, Solvent-Casted Nafion Membranes for Vanadium Redox Flow Batteries

The efficacy of metal oxide particles in mitigating vanadium ions crossover was investigated. 3 wt % SiO 2 was incorporated within recast Nafion membrane from which membrane electrode assemblies were prepared by painting. The composite membranes exhibited proton conductivities slightly lower (∼54–55 mS cm −1 ) than Nafion. However, the permeability of vanadium ions was lowered by 80–85%, while the performance was improved. These results demonstrated that loadings of SiO 2 much lower than previously reported can mitigate vanadium-ion crossover. Additionally the direct application of the catalyst on the membrane was shown to be a viable MEA synthesis option.