Hydrothermal synthesis, characterization and electrochemical properties of cobalt sulfide nanoparticles

In this article, we demonstrated a hydrothermal route to the synthesis of cobalt sulfide nanoparticles and investigated its application as an electrode material for supercapacitors. The crystalline nature, surface morphology and chemical states of the prepared cobalt sulfide nanoparticles are examined by X-ray diffraction analysis, Field-emission scanning electron microscope and X-ray photoelectron spectroscopic analysis, respectively. The cyclic voltammetry curves show the presence of redox pairs suggesting the pseudocapacitive behavior of cobalt sulfide electrodes with a specific capacitance of about 478.75 F/g at a scan rate of 5 mV/s. The electrochemical impedance analysis using Nyquist and Bode plots suggested the pseudocapacitive nature of the cobalt sulfide electrodes. A specific capacitance of about 505.88 F/g has been obtained from the galvanostatic charge-discharge measurements at a constant current density of 2 mA/cm(2). (C) 2015 Elsevier Ltd. All rights reserved.