Fabrication of Activated Carbon from Coconut Shells and its Electrochemical Properties for Supercapacitors

The problem posed by the use of fossil fuel energy and the increase in cost for energy storage materials, has led to the development of considerably cheap and environmentally friendly materials for energy storage. This has increased interest in biomass materials for synthesis of activated carbons, particularly as electrode materials for supercapacitor. For this research, coconut shell was utilized as a precursor material for the fabrication of activated carbon due to its availability, high carbon content, and the problem its disposal poses on the environment. Coconut shells were sourced locally, heated in a furnace, and activated using a two-step chemical activation with 1M H₂SO₄ and 1M KOH. The activated carbon was compacted and subjected to a cyclic voltammetry test using varied scan rates of 20, 40, 60, 80 and 100 mV/s, and a potential window between 0.05 and 0.8. The specific capacitance at scanning rates of 20, 40, 60, 80 and 100 mV/s are 600.89, 299.78, 378.31, 374.13, and 286.92 F/g respectively. The highest specific capacitance of 600.89 F/g and energy density of 46.94 Wh/kg was obtained at a scan rate of 20 mV/s. When compared with previous studies, the synthesized activated carbon electrodes from this research had the highest specific capacitance.