Synthesizes of Activated Carbon as Promising Electrode Materials for Supercapacitor Applications

Abstract

The Preparation of sustainable and highly efficient biochars as electrodes materials remains a challenge for developing green energy storage devices. In this study, proficient carbon electrodes were produced from activated carbon (AC) derived from agricultural wastes (corncob, groundnut shells and rice husk) for supercapacitor (SC) cell via a physio chemical technique. Biochars activated by potassium hydroxide (KOH) were explored as a prototype to be used for the preparation of electrodes for supercapacitor. The physical and chemical properties of the produced ACs were characterized using TGA, XRD, SEM and BET. The electrochemical performances of the constructed AC electrodes were studied using Electrochemical Impedance Spectroscopy (EIS). Thermal decomposition behavior TGA confirmed a suitable temperature of about 3500C for the carbonization of the agricultural waste precursors, the structural analyses using XRD confirmed the successful transformation of the carbon-containing waste into an amorphous and carbonaceous material. The BET analysis shows that surface area for the agricultural waste derived AC samples were 514.113, 950.046 and 1088.124 m2/g for corncobs, groundnut shells and rice husk respectively. The AC derived from rice husk have the largest developed micropore content as confirmed by SEM and BET, demonstrating its suitability for applications that requires high surface area materials than the corncob and groundnut shell ACs. The electrochemical performance of the electrodes was anlysed using EIS, the Nyquist Impedance plot shows that the rice husk AC electrode sample was the closest to vertical which indicates that it has the least parallel leakage reaction, followed by the corncob and ground nut shell AC samples respectively. These results suggested that agricultural waste derived ACs are promising candidates for high performance supercapacitors. In these studies, the rice husk was considered a higher efficiency precursor, followed by corncob and groundnut shell for bio-based electrode preparation to be employed in SCs.