Green biomass derived porous carbon materials for electrical double-layer capacitors (EDLCs)

Electrical double-layer capacitors (EDLCs) offer a probable alternative way to meet the need of increasing power especially in electric cars and digital electronic devices. The excellent power density achieved by EDLCs is due to use of porous electrodes that provide very high accessible surface area for ions. Porous carbon-based electrode materials are currently used because they possess very high specific surface area, relatively good electronic conductivity at a reasonable cost. The electrochemical properties of these devices are closely associated with chemical and physical properties of the carbon materials. In this regard, activated carbon (AC) is an important class of electrode material for the EDLCs application. The production of AC from cheap natural bio-precursors (especially crops and plants-based biomass) has been an attractive research area. In this perspective, an overview for the preparation of carbons and the associated activation processes is outlined. Furthermore, the electrochemical behavior including charge storage mechanism, the role of suitable pore sizes and recent research works on biomass derived carbon electrode materials for EDLCs are presented.