Abstract: Ruthenium oxide and manganese oxide nanomaterials were respectively prepared by a sol-gel process and hydrothermal synthesis method. The morphologies and microstructures of the composite nanomaterials were characterized by SEM and XRD. Based on the cyclic voltammetry, electrochemical impedance spectroscopy and constant current charge-discharge techniques, the performances of the electrodes were investigated. The results show that the composite of manganese oxide and ruthenium oxide is beneficial to improve the impedance characteristic. The electrode with 60% (mass ratio) manganese oxide has a high specific capacitance of 438 F/g and a lower inner resistance of 0.304 Ω using 38% (mass ration) H₂SO₄ solution. The capacitance retention of RuO₂/MnO₂ composite electrode was 92.5% after 300 cycles.

Key words: supercapacitor, ruthenium oxide, manganese oxide, specific capacitance