Capacitance behaviour of highly porous carbonsproduced by KOH activation

摘要

Various coal and pitch derived carbonaceous materials were activated for 5 hours at 8000C using potassium hydroxide andrn1:4 component ratio. Porosity development of the resultant activated carbons was assessed by N2 sorption at 77 K and theirrncapability of charge accumulation in electric double layer was determined using galvanostatic, voltammetric and impedancernspectroscopy techniques. Activated carbons produced from different precursors are all microporous in character but differ inrnterms of the total pore volume (from 1.05 to 1.61 cm3/g), BET surface area (from 1900 to 3200 m2/g) and pore sizerndistribution. Very promising capacitance values, ranging from 200 to 300 F/g, have been found for these materials in acidicrn1M H2SO4 electrolytic solution. The variations in the electrochemical behaviour (charge propagation, self-discharge,rnfrequency response) are considered in relation to the porous texture characteristics, elemental composition but also possiblerneffect of structural ordering due to various precursor materials used.