Preparation and characterization of peanut shell-based microporous carbons as electrode materials for supercapacitors

Abstract

Microporous carbons (PSC-1 and PSC-2) were obtained directly by the carbonization of peanut shells without and with NaOH solution pretreatment, respectively. Both samples have a main pore size of ~0.8 nm. The surface area increases from 552 m2·g-1 for PSC-1 to 726 m2·g-1 for PSC-2. Cyclic voltammograms (CVs) of the PSC-1 and PSC-2 electrodes and the symmetrical supercapacitors show almost rectangular shape indicating excellent capacitance features. The specific capacitances of PSC-1 and PSC-2 can reach 233 and 378 F·g-1, respectively, at a current density of 0.1 A·g-1 in a three-electrode system using porous carbon as the working electrode, a platinum electrode as the counter electrode and a Ag/AgCl electrode as the reference electrode. Furthermore, the electrodes in both three-electrode systems and supercapacitors show high stability and capacitance retainability after 1000 cycles. The formation mechanisms for the two microporous carbons and the relationship between the carbon materials and their electrochemical properties are discussed based on the experimental results. © Editorial office of Acta Physico·Chimica Sinica.