Design of best performing hexagonal shaped Ag@CoS/rGO nanocomposite electrode material for electrochemical supercapacitor application
(Department of Applied Chemistry, School of Sciences, Arts, Media and Management, Karunya Institute of Technology and Sciences (Deemed to be University), Karunya Nagar, Coimbatore-641 114, Tamil Nadu, India)
Abstract: The mixed metal/metal sulphide (Ag@CoS) with reduced graphene oxide (rGO) nanocomposite (Ag@CoS/rGO) was synthesized for the possible electrode in supercapacitors. Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method, implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework. The synthesized nanocomposite was subjected to structural, morphological and electrochemical studies. The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together. The band appearing at nearly 470.33 cm-1 in FTIR spectra can be ascribed to the absorption of S—S bond in the Ag@CoS/rGO nanocomposite. The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer. The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles. Based on the electrochemical performance, it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.
Key words: Ag@CoS/rGO electrode; hydrothermal reaction; physicochemical characteristics; electrochemical performance; electrochemical supercapacitor