Electron Spin Resonance Investigation of the Effects of Vanadium Ions in Ion Exchange Membranes for uses in Vanadium Redox Flow Batteries

Electron Spin Resonance (ESR) was used to characterize the effects of the vanadyl ion in Nafion 117. The ESR signal of a tempone spin probe was used as a qualitative standard to compare the signal intensity of the spin probe imbibed in the membrane with the intensity of the vanadium signal in the membrane. Initial measurements of vanadium crossover were recorded by monitoring vanadyl ion concentration increase in a blank solution flowed on one side of the battery apparatus as vanadyl ion solution was flowed simultaneously on the opposite side.