Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (10): 1972-1978.doi: 10.3866/PKU.WHXB20090934

• ARTICLE • Previous Articles     Next Articles

Kinetics of the VO2+/VO+2 Redox Couple on Carbon Paper Electrode with Heat Treatment

YUE Lu, LV Dong-Sheng, LI Wei-Shan, LEI Jian-Fei, ZHAO Ling-Zhi   

  1. School of Chemistry and Environment, South China NormalUniversity,Guangzhou 510006, P. R. China|Key Laboratory of Electrochemical Technology on Energy Storage and PowerGeneration in Guangdong Universities, Guangzhou 510631, P. R. China
  • Received:2009-04-15 Revised:2009-06-12 Published:2009-09-29
  • Contact: LI Wei-Shan E-mail:liwsh@scnu.edu.cn

Abstract:

Carbon paper was heat-treated at different temperatures and used as an electrode for the VO2+/VO+2 redox couple. Kinetics of the VO2+/VO+2 redox couple on the carbon paper electrode was studied using cyclic voltammetry (CV), polarization curves (PC), and electrochemical impedance spectroscopy (EIS). Results obtained from CV and PC show that the reaction rate constant and the exchange current of the VO2+/VO+2 redox couple on the carbon paper electrode increase as the heat treatment temperature increases. An equivalent circuit model for the VO2+/VO+2 redox couple on the carbon paper electrode was established. Fitting the experimentally obtained electrochemical impedance spectra with established equivalent circuits shows that heat treatment increases the double-layer capacitance of the carbon paper electrode and reduces the charge transfer resistance of the VO2+/VO+2 redox couple. Similar diffusion coefficients for VO2+ and VO+2 were obtained from CV and EIS, indicating that the established equivalent circuit model is consistent with the electrode process for the VO2+/VO+2 redox couple.

Key words: Kinetics, Carbon paper, Heat treatment, VO2+/VO+2, Redox

MSC2000: 

  • O646