一种新型氧化还原电解液电化学电容器体系

以含有Fe3+/Fe2+离子对的H2SO4溶液为电解液, 以多孔炭做电极材料, 就Fe3+/Fe2+离子对在多孔炭纳米孔隙中的电化学行为及准电容效应进行了探讨. 循环伏安测试结果表明, Fe3+/Fe2+离子对在多孔炭电极纳米孔隙中发生了可逆的电化学反应. 恒流充放电结果发现, 加入Fe3+/Fe2+使得充放曲线出现对称的充放电平台, 有效地提高了电化学电容器(EC)的电能存储容量, 其单电极比电容最高达174 mAh?g?1, 比单纯的H2SO4电解液的比电容高109 mAh?g?1, 且有着良好的循环稳定性. 根据实验现象及结果, 探讨了Fe3+/Fe2+离子对在EC电极上的充放电机理, 并提出了一种新的概念——氧化还原电解液电化学电容器.

A New Kind of Redox Electrolyte Electrochemical Capacitor System

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.