Effect of Electrolyte Concentration on Characteristics of Activated Carbon of Cocoa Peel

Abstract

Cocoa peel activated carbon has been successfully synthesized with 0.3 M KOH activator and NaCl electrolyte as the base material for supercapacitor electrodes. Variations in the concentration of NaCl electrolyte used were 1 M, 2 M, and 3 M to determine their effect on the capacitance, conductivity, and pore area values produced. The activated carbon produced was characterized by Scanning Electronic Microscope (SEM) to see surface morphology, X-Ray Diffraction (XRD) to determine carbon crystals, Cyclic Voltammetry (CV) and LCR-Meter to determine capacitance and conductivity values, and the Brunauer Emmett Teller method. (BET) to measure its surface area. The results of the Indonesian National Standard (SNI) test results obtained water content (8.6%), ash content (8.7%), volatile matter (26.2%), carbon content (65.1%), and iodine absorption (800 mg/g). The pore surface area can be increased by activation up to 24,742 m2/g. XRD analysis shows that the atomic structure is amorphous. Surface morphology proves that the increase in NaCl electrolyte concentration affects the pore structure. The higher the electrolyte concentration, the more even and finer the pore structure will be. The highest specific capacitance value was obtained at 3 M NaCl, which was 1.68375 F/g and the lowest was at 0.10771 F/g NaCl 1 M. The conductivity obtained is 1.83 S/m at 3 M NaCl at frequency of 1000 Hz and the lowest is 0.18 S/m at 1 M NaCl at 100 Hz. This proves that the electrolyte concentration can affect and increase the value of the capacitance and conductivity of the supercapacitor electrode.