Recent study has demonstrated that addition of metal cyanide mediators or redox species into polymer electrolytes can effectively increase the specific enrgy and power of supercapacitor to the levels of 30 Wh/kg at 1 kW/kg or 15 Wh/kg at 15 kW/kg. In order to further enhance the performance of the supercapacitors, the mediator-containg polymer electrolyte was absobed into a matrix of carbon nanotubes (CNTs) grown on carbon paper or metal foils (Fig. 1). A CVD process is optimized to ordered carbon nanotubes on the substrates with capability of controlling the ratio of semiconductor versus conductor CNTs. The electrode materials were used to fabricate full-cell supercapacitors with symetric or asymetric configurations. Three-electrode and full-cell electrochemical measurements were conducted to evaluate the performances of the supercapacitors. Galvanostatic charge-discharge results indicate that the specific energy was 39 Wh/kg at 1 kW/kg or 18 Wh/kg at 15 kW/kg. The cyclic voltammtry data show that the pseudocapacitors behave similarly as an electric double layer capacitor (EDLC). Self-discharge of the pseudocapacitors was also evaluated using open circuit voltage monitoring method. The self-discharge resistance was evaluated using an equivalent circuit model. The analytical results indicate that the self-discharge was improved by at least 1.5 times showing the effect of absorption of mediators into the CNT matrix.