The need of energy storage device with higher rating for wider application range has led to a great interest among engineers and researchers in proposing better materials for the device electrodes. The paper reports our current research progress in developing a new higher rating energy storage device like an electric double-layer capacitor (EDLC). New microporous carbons were systematically prepared by chemical reaction between mineral oil and strong acid, sulphuric acid, in various compositions. The graphitic nature of the produced microporous carbons were characterized by X-ray diffraction (XRD) measurement. Essential electrical properties of the microporous carbons for energy storage application, such as their capacitive behavior, were investigated by cyclic voltammetry measurements. In order to observe the frequency characteristics of the microporous carbons, one of the most important analytical tools known as electrochemical impedance spectroscopy was used. The experimental results of the XRD and electrochemical measurements are presented in forms of graphical plot.