ABSTRACT

Supercapacitors are considered as more promising energy storage systems compared to batteries and traditional capacitors, due to their fast charge-discharge rates, high energy density and power density, long cycling stability, and low cost. The performance of an electrochemical supercapacitor is mainly dependent on the electrode material. Cyclic voltammetry (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy are appropriate tools to demonstrate the electrochemical behavior of electrodes in a three-electrode system with a 3 M KOH electrolyte. The CV areas enlarged with an increasing scan rate, denoting good capacitance retention. The impedance plot illustrates a small semicircle at a high-frequency region and a straight line at a low-frequency region. The intercept of the plot at the real axis denotes the equivalent series resistance and the small semicircle stands for the charge-transfer resistance at the electrode/electrolyte interface.