English: Cyclic voltammetry at 3mV/s of 50 mM vanadium (IV) oxide sulfate hydrate in 50mM sulfuric acid solution showing redox reaction of vanadium species. Heat-treated Freudenburg carbon paper at 500 celsius for 3 hr is used as working electrode. The peaks for V(3+) | V(4+) transition are absent, because it is too slow for the timescale of this 3 mV/s cycling voltammetry.