Preparation of a Highly Porous Binderless Activated Carbon Monolith from Rubber Wood Sawdust by a Multi-Step Activation Process for Application in Supercapacitors

Abstract

Binderless activated carbon monoliths (ACMs) with high porosity that were prepared from self-adhesive pre-carbonized rubber wood sawdust were studied as electrodes for supercapacitors, focusing on the influence of activation time on the physical and electrochemical properties of the ACMs. The ACMs were activated under a flow of CO2 gas at a rate of 0.5 liters per minute and at a temperature of 900 oC. Activation time varied from 1 to 6 hours and with a multi-step heating profile. The ACM was characterized physically (density, porosity, structure and surface morphology) and electrochemically (specific capacitance, equivalent series resistance, energy and power density). This study found that the combined effects from the length of activation time, binderless property and multi-step heating had the greatest influence on the physical and electrochemical properties of the ACM. The optimum ACM was activated for 5 hours and had a specific capacitance, equivalent series resistance, energy and power density of 138 F g-1, 0.49 Ohm, 2.63 Wh kg-1 and 291 W kg-1, respectively.