Electrochemical Properties of Carbon Felt Electrode for Vanadium Redox Flow Batteries by Liquid Ammonia Treatment

. CV / . XPS , CV / . / 300 ℃ , , 6.93, 1.0, 4.5% . . In this study, nitrogen doped carbon felt (CFt) is prepared using thermal oxidation and liquid phase ammonia treatment to improve the efficiency for vanadium redox flow batteries (VRFB). The electrochemical properties of prepared CFt electrodes are investigated using cyclic voltammetry (CV) and charge/discharge test. The XPS result shows that the increase of liquid phase ammonia treatment temperature leads to the increased nitrogen functional group on the CFt surface. Redox reaction char-acteristics using CV reveal that the liquid phase ammonia treated CFt electrodes are more reversible than the thermally oxi-dized CFt. When CFt is treated by the liquid phase ammonia at 300 ℃, VRFB cell energy efficiency, voltage efficiency, and current efficiency are increased about 6.93%, 1.0%, and 4.5%, respectively, compared to those of the thermally oxidized CFt. These results are because nitrogen functional groups on CFt help to improve the electrochemical properties of redox reaction between electrode and electrolyte interface.