Highly Porous Carbon Sorbents Prepared from Bean Dregs for Electric Double-Layer Supercapacitor

Environment-friendly and cost-effective carbons were prepared for application in high-performance supercapacitors using bean dregs via carbonization and activation. The prepared samples were characterized using scanning electron microscopy and Brunauer–Emmett–Teller analysis. Furthermore, the electrochemical properties and capacitive behavior of the electrodes were systematically studied using cyclic voltammetry and AC impedance analysis. The porous carbon activated at 900 °C for 60 min had the largest specific surface area (3700 m2g−1) and the highest capacitance (260 F g−1) at a scan rate of 1 mV s−1.