Electrochemical Characterization of Supercapacitor Electrodes Prepared by Activation of Green Monoliths Consist of Self-Adhesive Carbon Grains and Lignin

Self-adhesive carbon grains (SACG) and lignin were prepared from fibres of oil palm empty fruit bunches by a low carbonization temperature and chemical treatment methods, respectively. Green monoliths were prepared from the KOH-treated SACG mixed with the organosolv-treated lignin with their weight percentages of 0%, 5%, 10%, 15% and 20%, respectively. The green monoliths were carbonized and activated into highly porous activated carbon monoliths (ACMs) electrodes for supercapacitor applications. The electrochemical characterization using galvanostatic charge-discharge (GCD) technique was carried out on the supercapacitor cell fabricated using these electrodes. The results show that the addition of 5 wt.% lignin was optimum, corresponding to the higher values of the specific capacitance (137 Fg-1), specific energy (4.13 Wh kg-1), specific power (192 W Kg-1), and a satisfactory value of equivalent series resistance (0.467 Ω) of the supercapacitor.