Electrochemical characterization on cobalt sulfide for electrochemical supercapacitors

High capacitance at a high charge-discharge current density of 50 mA/cm(2) for a new type of electrochemical supercapacitor cobalt sulfide (CoSx) have been studied for the first time. The CoSx, was prepared by a very simply chemical precipitation method. The electrochemical capacitance performance of this compound was investigated by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge tests with a three-electrode system. The results show that CoSx has excellent electrochemical capacitive characteristic with potential range -0.3 similar to 0.35 V (versus SCE) in 6 M KOH solution. Charge-discharge behaviors have been observed with the highest specific capacitance values of 475 F/g at the current density of 5 mA/cm(2), even at the high current density of 50 mA/cm(2), CoSx also shows the high specific capacitance values of 369 F/g. (c) 2006 Published by Elsevier B.V.