Roughened Graphite Felt Electrode with Enhanced Electrochemical Activity for Vanadium Redox Flow Batteries

摘要

A simple and effective method to roughen graphite felt (GF) by using manganese oxide as an etchingagent has been developed for vanadium redox flow battery (VRFB) application. The specific surfacearea of roughened GF (R-GF) prepared at the optimized conditions reaches 8.49 m 2 ·g -1 , 7 times largerthan that of the pristine one (P-GF), and more oxygen-containing functional groups are formed on theroughened surface. The experimental results show that the R-GF has higher peak current, smaller peakpotential separation and lower charge transfer resistance than those of P-GF and GF treated with airoxidation (O-GF). The VRFB with R-GF electrodes exhibits a strongly enhanced electrochemicalperformance in terms of energy efficiency and utilization ratio of electrolyte at different currentdensity. The large specific surface area with abundant oxygen-containing functional groups of R-GFhas been shown to be extremely beneficial for improving the kinetics of the VRFB.