Rapid and green synthesis of graphitic carbon from coconut shell waste by arc plasma for high performance symmetric supercapacitors

• Utilization of biomass waste to value added graphitic carbon. • No secondary toxic waste / byproduct generation at the end of the process. • Rapid processing and eco-friendly nature are the merits of the process. • Developed thermal plasma processing of coconut shell waste will be scaled up to treat large quantities. The sustainable conversion of biomass derived from low-cost agro waste into useful products is gaining popularity as global attention shifts towards green initiatives and energy efficiency. Coconut shell is considered as a potential raw material to synthesise carbon by burning it in a controlled atmosphere followed by physical / chemical activation. Various methods have been used to produce activated carbon from coconut shell. Production of graphitic carbon, which is preferred over activated carbon in supercapacitor applications, is a time consuming process and literature on the same from coconut shell is scanty. In this work, the graphitic carbon is produced rapidly and environment friendly by processing the coconut shell in thermal plasma and its potential use in energy storage applications are explored. Chemical composition, specific surface area, pore volume and average pore diameter of synthesized carbons are analyzed. An electrode for the supercapacitor is prepared from this material and electrochemical studies are performed. The specific capacitance and its retention as well as power and energy densities are notable and compared with previously published results.