Improvement of the structural and chemical properties of a commercial activated carbon for its application in electrochemical capacitors

The present paper shows that the performance of an inexpensive activated carbon used in electrochemical capacitors can be significantly enhanced by a simple treatment with KOH at 850oC. The changes in the specific surface area, as well as in the surface chemistry, lead to high capacitance values, which provide a noticeable energy density. The KOH-treatment of a commercial activated carbon leads to highly pure carbons with effective surface areas in the range of 1300-1500 mg and gravimetric capacitances as high as 3 times that of the raw carbon. For re-activated carbons, one obtains at low current density (50 mA g) values of 200 F g in aqueous electrolytes (1M H2SO4 and 6M KOH) and around 150 F g in 1M (C2H5)4NBF4 in acetonitrile. Furthermore, the resulting carbons present an enhanced and stable performance for high charge/discharge load in organic and aqueous media. * Corresponding author. Tel.: +34 985119090; Fax: +34 985297662. E-mail address: [email protected] (T.A. Centeno)