Abstract
Here we report a novel hydrothermal method to synthesize hybrid nanostructures based on single phase cobalt disulfide (CoS2) nanoparticles decorated on multiwalled carbon nanotubes (MWCNT) for application as supercapacitor electrode. This is also the first report on systematic investigation of the influence of MWCNTs on the electrochemical properties of CoS2 nanoparticle based electrode for supercapacitor. The X-ray diffraction and electron microscopic analyses revealed that incorporation of CNTs promotes the growth of only the CoS2 phase in the form of spherical nanoparticles with an average diameter of similar to 9 nm. CoS2-MWCNT nanohybrid electrode containing 20 wt % MWCNT showed the highest specific capacitance of 1486 F/g at 1 A/g discharge current density along with excellent reversibility. It also showed high cycle stability with similar to 80% retention of specific capacitance even after 10,000 cycles. Thus, we show a low cost and simple method to synthesize a CoS2-MWCNT nanohybrid that has great promise as electrode material for supercapacitor applications. Incorporation of CNT not only provides a conducting network for fast charge diffusion but (due to large surface area) also allows more CoS2 molecules to be readily available for redox reaction resulting in the reduction of the charge transfer resistance consistent with the data obtained from electrochemical impedance spectroscopy.