SYNTHESIS OF COBALT SULPHIDE THIN FILM ELECTRODE BY MODIFIED CHEMICAL BATH DEPOSITION ROUTE AND ITS SUPERCAPACITORS PERFORMANCE.

Cobalt Sulphide (CoS) thin films were synthesized on stainless steel (SS) substrates using a modified chemical bath deposition route. The supercapacitive properties of this compound were studied by cyclic voltammetry, galvanostatic charge-discharge test and electrochemical impedance spectroscopy. The as-prepared CoS thin film electrode has excellent electrochemical capacitive characteristic with potential range 0 to +0.7 V Vs Ag/AgCl at constant concentration 2M KOH solution. In cyclic voltammetry (CV) studies, effect of scan rate reveal that the CoS electrodes yield values of 531 Fgm-1 and 244 Fgm-1 for specific capacitance at scan rates of 10 mVs-1 and 100 mVs-1 respectively. Effect of concentration of electrolyte shows that, the specific capacitances values are increased from 60 to 351 Fgm-1 with increasing the concentration 1 M to 3 M of KOH. Stability studies at 50 mVs-1 scan rate reveal that the specific capacitance values are decreased from 322 to 186 Fgm-1 with increasing number of scan cycle. Charge-discharge behaviors have been observed that the supercapacitive parameters such as, specific energy (S.E.), specific power (S.P.) and coulombic efficiency (?%) are 11.4 Whkg?1, 7.4 KWkg?1 and 31%, respectively. Impedance spectroscopic analysis revealed that the equivalent series resistance (ESR) is 1.8 ? at the imaginary axis.