Improved electrochemical performances of CuCo2O4/CuO nanocomposites for asymmetric supercapacitors

The impact of reaction time on the electrochemical capacitive properties of CuCo2O4/CuO is reported. The CuCo2O4/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 physicochemical 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 CuCo2O4/CuO particles are visualized from FESEM and TEM analysis. The CuCo2O4/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 mVs(-1) with an energy density of 18 Wh kg(-1) and power density of 259 W kg(-1) at 1 mAcm(-2) in 1 M KOH electrolyte. In addition, this ASC retains nearly 100% of its initial capacitance over 5000 cycles. (C) 2015 Elsevier Ltd. All rights reserved.