二氧化锰超级电容器电极电化学性质

采用液相法制得α-MnO₂电极材料, 制备成电极并组装成对称型超级电容器. 采用恒流充放电、循环伏安、交流阻抗等方法在三电极体系下对超级电容器的正、负极进行测试, 分别研究它们在充放电过程中的电化学性能. 结果发现, 正极在0.31～0.41 V, 0.43～0.50 V (vs. Hg/HgO)发生电化学反应, 对电容器电压的影响起主要作用, 而负极则表现稳定未发生反应; 随着电极电位的增加, 反应电阻与接触电阻减小, 超级电容器电阻主要由负极决定; 负极表面双电层的形成速度小于正极, 而受电位影响的程度大于正极, 其电荷保持能力优于正极.

Electrochemical Performance of Electrodes in MnO2 Supercapacitor

α-MnO₂ was synthesized via a fluid phase way, and prepared as an electrode. Then the symmetry supercapacitor was assembled. Constant current charge-discharge, alternate current (AC) impendence and cyclic voltammetry were carried out to investigate the electrochemical performance of the positive and negative electrodes respectively in charge-discharge processes. The results suggest that some electrochemical reactions occur in the positive electrode in 0.31～0.41 V and 0.43～0.50 V (all vs. Hg/HgO) and determine the voltage of the supercapacitor. However, the negative electrode is relatively inert, with no reactions occurring. Both reactive and contact resistances diminish with the increase of electrode potential. The negative electrode resistance dominated the supercapacitor, and for it, the rate of double-layer formation on the surface of the negative electrode was less than that of the positive electrode, while the degree of the influence of potential on the negative electrode was more than that on the positive one, and its charge-keeping ability was better than that of the positive one.