Judul: Utilization of Activated Carbon Based Coconut Fiber and Bamboo as Supercapacitor Electrode
Abstrak: Supercapacitors also known as ultracapacitors or electrochemical capacitors are electrical energy storage devices which has a greater energy density than conventional capacitors and has a higher power density than batteries and has a long life cycle. In this study, the developed supercapacitor is an electrochemical double layer capacitor types namely supercapacitors with the capacitances that arise from the interface between the electrode and the electrolyte. The activated carbon is one of the material types that has been widely used as an electrode material for supercapacitors because it has a high specific surface area, chemical resistance, good electrical conductivity and reasonable price (Babel 2004; Fellman 2010; Aripin 2010). Coconut fiber and bamboo are used as a raw material in the manufacture of activated carbon because of its abundance availability in Indonesia, as well as the contain of lignin and cellulose with mostly composed of carbon that makes this both material suitable as an alternative material in the manufacture of activated carbon as a supercapacitor electrode. The activation process of coconut fiber and bamboo were carried out by varying the ratio of KOH 1:1, 2:1, 3:1 and the rate of water vapor (steam) 25 and 50 mL/bar to increase the distribution of pore size and specific surface area. The activated carbon that has been produced, was used in the making process of supercapacitor electrodes. The results showed that the activated carbon from coconut fiber and bamboo that has been activated with steam activation 25 mL/bar and KOH ratio 3:1, has a higher value of iodine adsorb power than the steam activation 50 mL/bars for alleged occurrence of an increase in pore size of micropores into mesopores which led to a decrease in the value of iodine adsorb power. In the meanwhile, an increase in conductivity value with increasing steam generated due to the lower density so that the value of increasing the conductivity of activated carbon. The results of the characterization surface morphology of the activated carbon samples from the coconut fiber and bamboo showed that the samples that activated on steam 50 mL/bar has more uniform, regular and smooth surface also tend to have larger pore sizes than the samples activated on steam 25 mL/bar. The characterization of the activated carbon crystallites structure from coconut fiber and bamboo showed that both samples have a graphite structure (composed of layers of carbon), and amorphous. Samples with steam activation 50 mL/bar has a value greater width of the layer and higher layer lower than the samples on the steam activation 25 mL/bars with spacing between layers relatively same. The measurement of the specific capacitance of activated carbon from coconut fiber and bamboo with cyclic voltammetry method showed that the value of the specific capacitance of activated carbon from bamboo possessed higher than the activated carbon from coconut fiber both on steam 25 and 50 mL/bar. It is thought to be related to the pore size distribution in the bamboo activated carbon is higher than the coconut fiber activated carbon, which leads to the formation of the interface vii between the electrode and the electrolyte in
Keyword: activated carbon of coconut fiber and bamboo, cyclic voltammetry, pore size distribution, specific capacitance, supercapacitor