Cherry stones as precursor of activated carbons for supercapacitors

It is shown that cherry stones-wastes can be recycled as activated carbons for electrode material in super-capacitors. KOH-activation of this precursor at 800-900 degrees C is an efficient process to obtain carbons with large specific surface areas (1100-1300 m(2) g(-1)), average pore sizes around 0.9-1.3 nm, which makes them accessible to electrolyte ions, and conductivities between 1 and 2 S cm(-1). These features lead to capacitances at low current density as high as 230 F g-1 in 2 M H2SO4 aqueous electrolyte and 120 Fg(-1) in the aprotic medium 1 M (C2H5)(4)NBF4/acetonitrile. Furthermore, high performance is also achieved at high current densities, which means that this type of materials competes well with commercial carbons used at present in supercapacitors. (c) 2008 Elsevier B.V. All rights reserved.