On-line mass spectrometry study of electrochemical corrosion of the graphite electrode for vanadium redox flow battery

The electrochemical corrosion of the graphite electrode for vanadium redox flow battery is investigated by on-line mass spectrometry analysis. The results show that CO2 and CO form and evolve more preferably than O2 on the graphite anode, which lead to the electrochemical corrosion of the graphite electrode. Furthermore, the evolution rate of O2 is the highest one among evolved gases if the polarization potential becomes too positive. The oxidation of VO2 + on the graphite electrode in 2 M H2SO4 + 2 M VOSO4 hinders the carbon oxidation reaction and retards the electrochemical corrosion of the graphite electrode.

► The corrosion of graphite electrode is investigated by on-line mass spectrometry.
► CO2 and CO form and evolve more preferably on the graphite electrode than O2.
► Evolution rate of O2 can be the highest if the potential becomes too positive.
► Oxidation of VO2 + on the graphite electrode hinders carbon oxidation reaction.