In this study, boron - doped carbon was prepared by reducing carbon dioxide (CO2) at high temperature by using sodium borohydride (NaBH4). The boron - doped carbon was coated on carbon felt and applied as an electrode for a vanadium redox battery cell. As a result of electrochemical performance evaluation, reversibility of carbon felt coated with boron doped carbon compared to pure carbon felt was improved by about 20% and charge transfer resistance was reduced by 60%. In the charge / discharge results, energy density and energy efficiency were improved by 21% and 12.4%, respectively. These results show that carbon produced by reduction of CO2 can be used as electrode material for redox flow battery.