Characterization of Carbon Electrode for Redox Flow Battery by Potential-controlled Method

In order to establish an analysis method useful for improving the performance of redox flow batteries (RFBs), electrochemical characterization based on potential control was performed on vanadium electrolyte for three different types of carbon felt electrodes. From the current (I) - potential (E) curve, differences of redox potential of vanadyl ions were observed among three electrodes. Furthermore, when comparing the quantity of electricity (Q) - potential (E) curves, a large difference was clearly observed in the reactivity with vanadyl ions. Scanning Electron Microscopy (SEM) observation and X-ray photoelectron spectroscopy (XPS) measurements showed that the defect structure of the carbon electrode and the oxygen content contained in the electrode are significantly related to the reactivity with vanadyl ions.