Abstract: A method is provided to enhance efficiency of carbon felts in a flow battery. The carbon felts are directly immersed in a mixed acid solution. The carbon felts with the solution are heated at a low temperature and processed through sonication. On surface defects of the carbon felts, —OH and C?O functional groups are efficiently generated. The functional groups catalyze the redox reaction of vanadium ions. More active positions are obtained on the carbon felts through the activation treatment. Both of valence exchange and redox velocity of the vanadium ions are enhanced. Thus, the present invention has simple and fast processes with easily regulated experimental parameters for good modification without high temperature treatment but low cost.

Abstract: A method is provided to enhance efficiency of carbon felts in a flow battery. The carbon felts are directly immersed in a mixed acid solution. The carbon felts with the solution are heated at a low temperature and processed through sonication. On surface defects of the carbon felts, —OH and C?O functional groups are efficiently generated. The functional groups catalyze the redox reaction of vanadium ions. More active positions are obtained on the carbon felts through the activation treatment. Both of valence exchange and redox velocity of the vanadium ions are enhanced. Thus, the present invention has simple and fast processes with easily regulated experimental parameters for good modification without high temperature treatment but low cost.

Abstract: A method of direct electrochemical oxidation is provided to modify carbon felts of a flow battery. Redox reactions are used for modification. Therein, voltage is directly conducted to the cell stack. The carbon felts of the cell stack are uniformly contacted with electrolytes for processing electrochemical reactions. As a result, modification is done to generate oxygen-containing functional groups (—COOH, —OH) on surfaces of the carbon felts. Thus, the present invention has the following advantages: Operation and procedure are easy and quick. Experimental parameters and conditions can be easily regulated and replaced without dismantling a device used for modification. The device used can withstand a wide range of voltage and current. Modification effect can be obtained with low cost yet without high-temperature treatments.