Electrochemical Modification of Graphite Felt Electrode for Vanadium Redox Flow Battery

Electrochemical oxidation of graphite felt was investigated so as to enhance the electrochemical performance of this material for using in vanadium redox cell. Electrochemical activity of the graphite felt in vanadium electrolyte increases with its extent of oxidation. Cell voltage efficiency of over 90% and current efficiency of over 92% are obtained after treatment. Both XPS and FT-IR analysis demonstrates that surface functional groups of COOH increase mainly compared with untreated samples. SEM shows the surfaces are eroded. BET/N-2 measurements show the surface area increases. The improvement of electrochemical activity for the electrode is ascribed to the increase of the number of COOH group and the special surface.