| Much research focus on redox flow batteries in recent years. Sodium polysulfide/bromide redox flow battery(PSB) and vanadium ion redox flow battery(VRB) were the leading ones in redox flow batteries. Recent progress in research and development on PSB and VRB are reviewed and their advantages and disadvantages were compared. With this comparison, this thesis works on electrode materials for VRB. Composite electrodes with graphite(GP), acetylene black (AB) and carbon nanotube (CNT) were prepared and their performances were studied. Following results were obtained.1. Composite carbon electrodes with GP and AB were prepared. The voltammetric behaviors of the prepared electrodes were studied in 5mol/L H2SO4+1mol/L VOSO4 solution with cyclic voltammetry (CV), and the surface morphology of the composites was observed with scan electron microscope (SEM). The results obtained with voltammetry show that the redox couples ofⅤ(Ⅳ)/Ⅴ(Ⅴ) andⅤ(Ⅱ)/Ⅴ(Ⅲ), as positive and negative electrodes of all vanadium flow liquid battery, respectively, has good reversibility but low current on the GP electrode, and the current can be improved by AB. It is found with the observation of SEM that the granular AB disperses evenly on the surface of sheet GP when they are mixed together. The best composition for the positive and the negative of all vanadium flow liquid battery are determined by comparing voltammetric behavior of the composite electrodes with different content of AB, it is(wAB:wGP=)15:85 for the positive and 4: 96 for the negative.2. Composite carbon electrodes with GP and CNT were prepared. The effect of heat-treated CNT on the electrode performance was considered. The voltammetric behaviors of the prepared electrodes were studied in 5mol/L H2SO4+1mol/L VOSO4 solution with cyclic voltammetry (CV), and the surface morphology of the composites was observed with scan electron microscope (SEM). The results obtained with voltammetry show that the redox current can be improved by CNT as well. It is found with the observation of SEM that the CNT disperses evenly on the surface of sheet GP when they are mixed together. The best composition for the positive anti the negative of all vanadium flow liquid battery are determined by comparing voltammetric behavior of the composite electrodes with different content of CNT, it is (wCNT:wGP=) 5: 95 for the positive and the negative. Carbon nanotube treated at 200℃temperature in vacuum shows its better effect to improve the performance of the composite electrodes.
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