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.