Utilization of carbon-black industry waste to synthesize electrode material for supercapacitors

Solid waste utilization in synthesizing porous carbon materials for supercapacitor electrodes has been a fast-progressing research domain in past decades. Different types of agricultural and industrial waste have the potential to act as a precursor supply for carbon with porous structures. In this study, the waste generated from a furnace-grade conductive carbon black manufacturing industry was utilized to synthesize porous carbon through pyrolysis at 400 degrees C for 2 hours, followed by chemical activation at 800 degrees C for 1 hour. Different activating agents, precisely, potassium hydroxide, orthophosphoric acid, and zinc chloride, were used. Similar activation conditions as well as the mass ratio of activating agent to sample (4:1), were maintained to make a comparative study. All three samples were then tested in a three-electrode set-up through cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy for their performance as electrode material for supercapacitors with a mass loading of 4.0 mg/cm2 in 1 M Na2SO4 electrolyte. The largest specific capacitance was obtained for the KOH-activated sample, that is, 21.3 F/g, followed by 17.9 F/g for H3PO4 activated sample and 13.7 F/g for the ZnCl2-activated sample, at a scan rate of 50 mV/s. Though the obtained capacitance is much smaller for its practical application, the study acts as a base for further modifications and upgrades to utilize this high carbon-containing waste in energy storage. The waste from a furnace-grade conductive carbon black manufacturing industry was used as the precursor for synthesizing activated carbon using the thermochemical method. Three different chemical activating agents were used, and the synthesized samples were compared for their performance as supercapacitor electrode material. image