Development of carbon felt electrode using urea for vanadium redox flow batteries

In this study, nitrogen doped carbon felt was prepared by pyrolysis of urea at high temperature and applied as an electrode for vanadium redox flow cell. Urea is easier to handle than ammonia and forms NH2 radicals at higher temperatures, creating a nitrogen functional group on the carbon surface and acting as an active site in the vanadium redox reaction. Therefore, the discharge capacity of activated carbon felt electrodes using urea was 14.9 Ah/L at a current density of 150 mA/cm², which is 23% and 187% higher than OGF and GF, respectively. These results show the possibility that activated carbon felt electrode using urea can be used as electrode material for redox flow battery.