About the book
The use of supercapacitors as secondary energy storage devices has been considered in many countries. They have attracted significant attention because of their ability to serve as power supplies for electric vehicles/heavy machines and to address the growing demand for high-power-density storage devices. Supercapacitors, which typically contain activated carbons as the primary constituents, have a remarkably long service life (compared to that of chemical batteries) and excellent discharge characteristics. These devices can store charge and electrostatic energy in the double layer that forms at the interface between the micro/nanoporous electrode and the electrolyte solution. Activated carbons are often used as the micro/nanoporous electrode for supercapacitors because they have high specific surface areas. In addition, such electrodes undergo minimal deterioration through a wide range of applied potentials, exhibit good cycling characteristics, and do not require maintenance. Therefore, electrochemical studies on carbon-based electrodes and carbon-based materials from biomass have been conducted on a global scale. Recently, the disposal of large amounts of biomass waste has become a serious problem in the rural region of some country; thus, the book suggests a plausible method for reusing biomass waste to produce low-cost large-capacitance/high-energy density carbon materials for electric double-layer capacitors, pseudocapacitors and hybrid capacitors.