Preparation of activated carbon as supercapacitor electrode materials from cassava rhizome

Abstract

In this study, activated carbon (AC) was prepared from raw cassava rhizome (CR) and CR hydrochar which was derived from a hydrothermal carbonization process at 200°C for 1 h in 0.4 M of aqueous HCl. The chemical activation process was further conducted using a raw material to ZnCl2 ratio of 1:3 at 800°C for 2 h under nitrogen atmosphere. Elemental compositions, graphitization degree, porosity, specific surface area (SSA), surface chemical functional groups and morphology of the AC were investigated. The analysis results demonstrated that the AC derived from raw CR (CRZ83) provided promising properties for using as supercapacitor electrode material (SEM). It had higher total pore volume (1.53 cm3/g) and SSA (1,225 m2/g) than those of the AC prepared from CR hydrochar (CRHZ83). Electrochemical potentials of the CRZ83 were investigated using a three-electrode system in 1 M H2SO4 electrolyte. Its specific capacitance was 123.0 F/g at a current density of 0.3 A/g. The results could suggest that the AC prepared from raw CR can be an alternative material for supercapacitor electrodes.