Hydrothermal Synthesis of Supercapacitors Electrode Materials

Abstract

Nowadays, electrochemical capacitors have been considered as one of the important power sources to overcome the environmental problems such as depletion of fossil fuels and increase in energy demand. The electrochemical capacitors are considered promising energy storage devices because they store a large amount of energy in comparison to the conventional capacitors and deliver higher power than batteries. Electrochemical capacitor electrodes play a vital role in enhancing the electrochemical performance, especially their active materials (i.e., carbonaceous, transition metal oxide and conducting polymers). In general, carbonaceous materials exhibited large surface area and high conductivity and hence are widely used as electrode materials for electrical double-layer capacitor system. In contrast, transition metal oxides and conducting polymers have been adopted for fabrication of pseudocapacitor electrodes owing to their storage mechanisms. In order to fully utilize the advantages of electrical double-layer capacitors and pseudocapacitors, hybrid capacitors have attracted great attention in the field of electronic devices and electric vehicles. Thus, this chapter presents a critical review of recent developments of the hydrothermal synthesis technique for hybrid capacitors' electrodes in terms of their specific capacitance, voltage window, current density, cycling stability, and current density.