Acta Phys. -Chim. Sin. ›› 2006, Vol. 22 ›› Issue (12): 1445-1450.doi: 10.3866/PKU.WHXB20061203

• ARTICLE • Previous Articles     Next Articles

A New Kind of Redox Electrolyte Electrochemical Capacitor System

LI Qiang;LI Kai-Xi;SUN Guo-Hua;FAN Hui;GU Jian-Yu   

  1. (Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100049, P. R. China)
  • Received:2006-05-19 Revised:2006-06-28 Published:2006-12-06
  • Contact: LI Kai-Xi

Abstract: The electrochemical characteristics and pseudocapacitive effects of Fe3+/Fe2+ ion pair were investigated in an electrochemical capacitor (EC) system using porous carbon as electrode material and with H2SO4 solution containing Fe3+/Fe2+ ion pair as electrolyte. The cyclic voltammetric results indicated that highly reversible electrochemical redox reactions of Fe3+/Fe2+ ion pair occurred within the nano-pore structures of the porous carbon electrodes. Symmetrical charge/discharge cycles were achieved due to the existence of Fe3+/Fe2+ ion pair, which effectively improved the capacity of the electrochemical capacitor system. Apart from its excellent cyclic stability, the specific capacitance of the single electrode system reached 174 mAh•g−1, which is 109 mAh•g−1 higher than that obtained for H2SO4 as the electrolyte. The charge/discharge mechanism of Fe3+/Fe2+ ion pair in the EC systems was discussed and a new type of redox electrolyte electrochemical capacitor was suggested.

Key words: Electrochemical capacitor, Faradic pseudocapacitance, Porous carbon, Fe3+/Fe2+ ion pair, Electrosorption