Revista de Ciências e Engenharia de Materiais

Synthesis of Activated Carbon/Chitosan Composites and Expanded Graphite for Symmetric Supercapacitor

Abstract

Galen Noel G Nifas and Rex S Forteza

Supercapacitors have great electrochemical characteristics such as high energy and power densities, chargedischarge rates, and extremely long cycle life which make them favourable in electronics and other applications. Activated carbon was successfully coated with chitosan, and natural graphite flakes were chemically and thermally modified into expanded graphite; these were structurally and morphologically analysed using FTIR and SEM. FTIR analysis showed the presence of N-H scissoring from amine and amide groups, C-O and C≡C stretching for activated carbon/chitosan (AC/CH) composites and OH group, C=C and C-O stretching for expanded graphite (EG). SEM images show that AC/CH and EG have porous structures; AC/CH has chitosan chunks on activated carbon surface. The fabricated supercapacitors were tested for their specific capacitances, charging rates, and energy and power densities. At potential window of 0.001 V, the lowest specific capacitance, charging rate, energy density, and power density are 0.49 ± 0.0060 F/g, 0.12 ± 0.0018 mC/s, 6.853 × 10^-8 Wh/kg, and 1.556 × 10^-4 W/kg, respectively, which are obtained from 100% EG treatment. The symmetric supercapacitors can reach a specific capacitance of 272 ± 14.47 F/g, charging rate of 65.3 ± 0.81 mC/s, and energy density of 3.786 × 10^-5 Wh/kg and power density of 0.0817 W/kg with 50% AC/CH-50% EG treatment.