Binary nickel cobalt oxide (NixCo3-xO4) nanostructures as stable and high-energy density asymmetric supercapacitor electrode material

Abstract

Nickel cobalt oxides are very desirable for a wide range of scientific research and practical applications due to their smooth redox activity and unquestionable parameter optimization freedom. This report examines the capacitive behaviour of hydrothermally fabricated nickel cobalt oxide nanostructures for potential application in the field of energy storage. According to the findings of our research, the morphology of the nickel-cobalt oxides is highly dependent on reaction time as well as the ratio of Ni/Co. When NiO, NixCox-3O4(I) and NixCox-3O4(II) are deposited on nickel foam, the fabricated electrodes show a specific capacitance of 291, 590, 1948 F g-1 respectively, scanned at 5 mVs−1 in an aqueous electrolyte containing 4 M KOH. The NixCox-3O4(II) electrode shows less cycle fatigue as its initial capacitance dropped by just 17% even after 10k cycles and demonstrating low impedance confirmed by electrochemical impedance spectroscopy (EIS). Moreover, the solid state asymmetric capacitor fabricated by using NixCox-3O4(II) as positive and activated carbon as negative electrode demonstrates the specific energy and power of 38 Whkg−1, 3.3 kW kg−1respectively. These remarkable electrochemical properties, characterized by exceptional stability and high energy density, demonstrated by the NixCox-3O4(II) based electrode unequivocally establish it as an indispensable and highly promising electrode material for utilization in electrochemical energy storage devices.