Studies on sustainable CuO/ZnO@MWCNT electrodes and their supercapacitive performances in redox additive electrolyte

Abstract

Supercapacitive performances of copper oxide and zinc oxide loaded multiwalled carbon nanotube (CuO/ZnO@MWCNT - CZM) nanocomposites (NCs) in redox additive electrolyte were reported. CZM NCs were hydrothermally synthesized and calcinated at 500 °C for 5 h. The structural characteristics of the prepared NCs were examined using powder X-ray diffraction analysis. Scanning electron microscopy and vibrational spectroscopy techniques were employed to analyse the surface features and molecular interactions of the prepared NCs, respectively. The working electrodes were fabricated using CZM NCs and tested in pure 3 M potassium hydroxide (KOH) and 0.2 M potassium ferrocyanide added 3 M KOH electrolytes (K4[Fe(CN)6] – RAE). Fabricated electrode exhibited the specific capacitances of 199.4 Fg−1 (at 8 Ag−1) in KOH and 1829.43 Fg−1 (at 15 Ag−1) in RAE, respectively. Furthermore, an asymmetrical-type supercapacitor was constructed using CZM NCs and activated carbon-coated Ni foil as the working and counter electrodes, respectively. Fabricated device demonstrated 18.5 W h kg−1 and 1875 W kg−1 of energy and power densities, respectively, with 83.05 Fg−1 of specific capacitance in RAE. Electrochemical studies confirmed that the prepared CZM NCs demonstrated superior performances in RAE.