Nanostructured carbide-derived carbons (CDC) were synthesized from Ta 4HfC5 and WTiC2 powders via gas phase chlorination within the temperature range from 800 to 1100°C. The results of X-ray diffraction, high-resolution transmission electron microscopy and Raman spectroscopy showed that the synthesized CDC materials are mainly amorphous, containing relatively small graphitic crystallites. The scanning electron microscopy data revealed the breaking down of the initial carbide particles into smaller ones. The low-temperature N2 sorption experiments were performed and the specific micropore surface areas up to 1950 m2 g-1 and 1880 m2 g-1 were obtained for Ta 4HfC5-CDC and WTiC2-CDC, respectively. The energy-related properties of the supercapacitors based on 1 M (C 2H5)3CH3NBF4 solution in acetonitrile and Ta4HfC5-CDC or WTiC2-CDC as an electrode material were investigated using the cyclic voltammetry, electrochemical impedance spectroscopy, galvanostatic charge/discharge and constant power charge/discharge methods. The Ragone plots (using the total material weight or volume of two electrodes) for the supercapacitors based on the Ta4HfC5-CDC and WTiC2-CDC electrodes have been calculated from constant power tests within the potential range from 3.0 to 1.5 V, demonstrating the high gravimetric (28 Wh kg-1) and volumetric (18 Wh dm-3) energy densities at high power density (10 kW kg-1 and 15 kW dm-3, respectively).