Supercapacitors from high fructose corn syrup-derived activated carbons

Abstract Hydrothermal processing and physical activation are used to prepare activated carbons from high fructose corn syrup. The activated carbons are present in spherical shape and possess a high surface area of 1473 m2 /g. Both the surface area and micropore fraction increase with the increase of the activation time. Using the prepared activated carbons as electrodes and 6 M KOH aqueous solution as electrolyte, supercapacitor cells of symmetrical type (two electrodes) are constructed. The electrochemical performance of the supercapacitor cells is investigated. The experimental results show the increase of the specific gravimetric capacitance with the increase of the total surface area, suggesting the importance of the activation time in controlling the porous characteristics of the activated carbons and the electrochemical characteristics of the supercapacitor cells made from the activated carbons. The largest specific capacitance and energy density achieved are 168 F/g at an electric current density of 0.2 A/g and 4.2 W h/kg at a power density of 1.5 kW/kg. The micropores play a dominant role in the energy storage of the supercapacitor cells made from the prepared activated carbons.