Global warming is rapidly becoming a major concern as a result of the continuing emissions of greenhouse gases generated by the combustion of fossil fuels. To resolve this problem, various studies on efficient energy storage devices have been undertaken. Electronic technologies are increasingly used in electronic products and systems, and they require effective energy storage [1,2]. Supercapacitors are energy storage devices with high power density and long cycle life, and have been spotlighted in recent years because of their promising applications in portable devices, electric vehicles, transporta-tion systems, digital devices. The two main types of electrochemical capacitors are elec-trical double-layer capacitors (EDLCs) and pseudo-capacitors. The operating mecha-nism of the electric double-layer capacitors depends on the pore structure of the electrode materials, while the operating mechanism of pseudo-capacitors is based on their active electrode materials, where faradic redox processes occur [3-6]. In EDLCs, the charge is stored by an electric double layer at the electrode-electrolyte interface. The charge stor-age mechanism is a non-Faradaic process, and carbon-based materials such as 2-D gra-phene and 1-D carbon nanotubes (CNTs) are frequently employed as the electrode mate-rial for this type of supercapacitor. Because of the electrical charge separation at the interfaces between the electrically conductive electrode and the electrolyte, they exhibit high power density [7,8]. In pseudo-capacitors, to accommodate the fast and reversible redox reaction process, transition metal oxides [9,10] or conducting polymers [11-13] are used as electrode materials, and capacitance is formed at the interface of the elec-trode and electrolyte by a reversible faradaic process.