钒氧化还原液流电池石墨-炭黑复合电极性能

Performance of graphite powder-carbon black composite electrodes for the vanadium redox flow battery

采用循环伏安法研究了炭黑和石墨材料对电极电化学性能的影响。炭黑-石墨的复合材料电极,不仅综合了单纯的石墨和炭黑的优点,而且还完整地出现了钒离子电对V2+/V3+、V3+/VO2+和VO2+/VO2+三对氧化还原峰,并且表现出较好的电化学活性。在所研究的范围内,较合适的质量配比为:m (石墨)︰m(炭黑)=3︰1。分别计算了各种钒离子电化学反应扩散系数D0,其中VO2+/VO2+电对的还原反应中D0可达到4.44×10-5 cm2·s-1,显示了良好的电化学活性。

Carbon black(CB)-graphite powder(GP) composite electrodes were evaluated for their electrochemical performance by cyclic voltammetry. The results show that the electrochemical behaviour of the V2+/V3+ redox couple is reversible, while the V3+/VO2+and VO2+/VO2+ redox couples are irreversible at this composite electrode materials. The experiments reveal that the optimum ratio of this composite material is 3︰1 (GP/CB). The diffusion coefficients of the redox reaction of each vanadium ion couples are calculated. The best one which reaches 4.44 ×10-5 cm2·s-1 is that of the reduction of VO2+/VO2+.The properties show that this composite electrode can meet the need of charge-discharge at high current.