Hierarchical Porous Carbon Prepared through Sustainable CuCl2 Activation of Rice Husk for High‐Performance Supercapacitors

Abstract Porous carbon material has been widely used as the electrode material for supercapacitor owing to distinctive advantages of high electrical conductivity, low cost and availability at ease. In this study, rice‐husk‐derived porous carbon (RHPC) is successfully prepared by employing a new activation agent copper chloride (CuCl 2 ). The morphology and porous structure of RHPC are characterized by scanning electron microscope and N 2 adsorption/desorption. The electrochemical performances of RHPC are investigated by alvanostatic charge‐discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The RHPC possesses high porosity and large specific surface area. When used as supercapacitor electrode materials, RHPC exhibits high specific capacitance of 165.23 F⋅g −1 at a current density of 0.5 A⋅g −1 , excellent cycle stability and noticeable high‐rate capacity of 151.69 F⋅g −1 even at a high current density of 20 A⋅g −1 . More importantly, the preparation of this CuCl 2 activator is facile and low‐cost. Besides, the recyclability meet the requirements of environmental concerns.