Preparation and electrochemical performance of Convolvulus arvensis-derived activated carbon for symmetric supercapacitors

The increasing demand for clean and green energy appeals to developing environment-friendly, efficient, and economical electrode materials for supercapacitors. In this work, we have prepared activated carbon from Convolvulus arvensis L. (CAAC) and used it as electrode material for symmetric supercapacitors. Pyrolysis and NaHCO₃ activation were both used in the preparation of the CAAC. The characterization confirmed the high degree graphitization of the CAAC with ample pores and exhibited a specific surface area of ∼ 680 m²/g. The developed CAAC-based symmetric supercapacitor resulted in a specific capacitance of 103 F/g at a 0.5 A/g current density, while it has a high energy density of 14.2 Wh/kg at a 250 W/kg power density. The CAAC-based symmetric supercapacitor is reliable because it retains nearly all of its initial capacitance (∼97%) and nearly all of its Coulombic efficiency (∼94%) even after being subjected to 5000 charge–discharge cycles.