应用循环伏安、交流阻抗(EIS)等方法,研究了硫氰酸钾(KSCN)添加剂对石墨电极上(正极)钒电池电对(VO2+/VO2+)动力学特征及电池性能的影响.结果表明:1)KSCN的添加提高了VO2+/VO2+电对氧化峰的峰电流,但对还原峰的影响很小;2)添加KSCN,增加了充放电电量,提高了钒电池中活性物质的利用效率;3)VO2+/VO2+电对的速率常数K0,随着KSCN浓度的增加而逐渐增大.
In order to improve the reaction activity of VO2+/VO2+ and the battery performance of Vanadium redox flow battery,different concentration of potassium sulfocyanates KSCN were added into 0.1mol/L VOSO4/ H2SO4 solution,and the kinetic characters of electrochemical reaction of VO2+/VO2+ was studied by CV and EIS.The results showed that the addition of KSCN could improve the oxidative peak current value of positive couple VO2+/VO2+ reaction,but had little influence in the reductive peak.The addition of KSCN decreased the impedance at 1.0 V.And the value of standard rate constant k0 was also improved with the concentration of KSCN increased.The total coulomb during the charge and discharge processes increased after the addition of KSCN,which means that the usage efficiency of active species in the VRB solution was improved.
[1]Rychcik M,Skyllas-Kazacos M.Characteristics of anew all vanadium redox flow battery[J].J PowerSources,1988,22:59-67.
[2]Skyllas-Kazacos M,Rychcik M,Robins R G,etal.New all-vanadium redox cell[J].J Electrochem Soc,1986,133:1057-1058.
[3]Skyllas-Kazacos M,Grossmith F.Efficientvanadiumredox flow cell[J].J Electrochem Soc,1987,134(12):2950-2953.
[4]Gu Jun(顾军),LI Guang Qiang(李光强),Xu Qian(许茜),et al.Progress of research on vanadium redoxflow battery PartⅠ:Principles and progress of the bat-tery[J].Chinese Journal of Power Source,2000,24(2):116-119.
[5]Skyllas-Kazacos M,Kasherman K,Hong D R,et al.Characteristics and performance of1 kW vanadium redoxbattery[J].J Power Sources,1991,35:339-40.
[6]Liu Di(刘迪),Tan Ning(谭宁),Huang Ke Long(黄可龙),et al.Electrochemical oxidation of graphite feltmaterials for vanadium redox flow battery application[J].Chinese Journal of Power Source,2006,30(3):224-226.
[7]Sun E,Skyllas-Kazacos M.A study of the V(Ⅱ)/V(Ⅲ)redox couple for redox flowcell applications[J].J Power Sources,1985,15:179-190.
[8]TomooY,Nobutaka W,Takashi Y,et al.Electron-transfer kinetics of Np3+/Np4+,NpO2+/NpO22+,V2+/V3+and VO2+/VO2+at carbon electrodes[J].Journal of the Electrochemical Society,2005,152(4):A830-A836.
[9]Frechette E,Comperc C,Ghali E.Evaluation of thecorrosion resistance of painted steels by impedancemeasurements[J].Corrosion Science,1992,33(7):1067-1081.
