Improved electrochemical performances of CuCo2O4/CuO nanocomposites for asymmetric supercapacitors

ABSTRACT The impact of reaction time on the electrochemical capacitive properties of CuCo 2 O 4 /CuO is reported. The CuCo 2 O 4 /CuO nanocomposites are synthesized by microwave assisted reflux method at different reaction times (1, 5, 10 and 15 min) and are subjected to necessary characterization techniques to find its physico-chemical properties. The compound formation temperature is identified through TG/DSC analysis. Subsequently the phase formation is envisaged from XRD analysis. The characteristic functional groups and valency state of the elements are revealed from FT-IR and XPS analysis, respectively. The spherical and rod-like shape CuCo 2 O 4 /CuO particles are visualized from FESEM and TEM analysis. The CuCo 2 O 4 /CuO prepared at 5 min reaction time provides the enhanced capacitance of 781 F g −1 at 2 mV s −1 in 1 M KOH electrolyte. Further the asymmetric supercapacitor (ASC) is fabricated with activated carbon (AC) as negative electrode, which rendered the specific capacitance of 141 Fg −1 at 1 mV s −1 with an energy density of 18 Wh kg −1 and power density of 259 W kg −1 at 1 mA cm −2 in 1 M KOH electrolyte. In addition, this ASC retains nearly 100% of its initial capacitance over 5000 cycles.