Activated oil sands fluid coke for electrical double-layer capacitors

Electrochemical capacitors are important energy storage devices that have high power density, rapid charging cycles and are highly cyclable. In this study, activated fluid coke has demonstrated high surface area, improved capacitive properties, and high energy density. Fluid coke is a by-product generated from continuous high temperature bitumen upgrading, resulting in the formation of nearly spherical particles with concentric carbon layers. The residual sulphur impurities in fluid coke may enhance its energy storage performance. The activated coke samples have high specific surface areas, up to 1960 m(2) g(-1), and show promising capacitive performance, in 4 M KOH electrolyte, with high gravimetric and specific capacitances of 228-257 F g(-1) and 13-14 mu F cm(-2), respectively. These results are comparable to other top performing activated carbon materials [1-3]. The activated fluid coke maintains high performance at fast charging rates, greater than 160 F g(-1) at a current density of 7500 mA g(-1). Activated fluid coke's high capacitance and promising rate performance are potentially associated with its unique layered, and the moderate sulphur content in the chemical structure. Activated fluid coke is a unique opportunity to use a limited use by-product to generate activated carbon that has a high surface area and promising energy storage properties. (C) 2014 Elsevier B.V. All rights reserved.