Abstract:In order to improve electrochemical activity of the anode side electrode of vanadium battery, carbon nanotube were modified by liquid phase oxidation method and introduced into graphite felt to prepare composite electrode. Firstly, the electrochemical properties of carbon nanotube and graphite felt were compared, and then the electrochemical activity of carbon nanotube was further optimized by liquid phase oxidation modification. Finally, the carbon nanotube graphite felt composite electrode was prepared, and its performance was investigated by charging and discharging test. The results show that the electrochemical activity of carbon nanotube is the best under the conditions including volume ration of concentrated H2SO4 to concentrated HNO3 of 1︰3, temperature of 80 ℃, and treatment time of 2 h. Under the current density of 120 mA/cm2, the voltage efficiency and energy efficiency of the negative electrode of the composite electrode are 87.96% and 83.47%, respectively, which are 5.88 and 6.16 percentage points higher than that of the graphite felt (82.08% and 77.31%), and the composite electrode has better rate performance.