Tailoring the porous texture of activated carbons by CO₂ reactivation to produce electrodes for organic electrolyte-based EDLCs

Highly microporous carbon obtained by KOH etching of carbohydrates exhibited enhanced specific capacitance due to the increased adsorption of electrolyte ions on its large surface, which renders it a promising electrode material. However, the KOH-activated carbon electrode did not achieve its optimum charge capacity in organic electrolytes due to the limited accessibility of the electrolyte ions to the micropores, which hindered the adsorption of ions. The electrode performance was enhanced by enlarging the micropores of KOH-activated carbon to mesopores via reactivation in a stream of CO₂, which allowed the mesopore/micropore ratio to be increased without compromising the originally high specific surface area. The extended amount of mesopores increased the charge capacity of the electrode by enabling the large organic electrolyte ions to access the porous surface, as compared to untreated KOH-activated carbon.