Investigation of the dielectric and electrochemical properties of Co3O4–NiO nanocomposites with varying NiO content

A facile sol-gel ultrasonication route has been adopted for synthesizing Co3O4/NiO nanocomposite series, which has been analyzed for their dielectric and electrochemical properties and compared with their components i.e. NiO & Co3O4. The synthesised specimens were characterized using various experimental techniques such as X-Ray diffraction (XRD), Scanning electron microscope (SEM) with Energy dispersive X-Ray Spectroscopy (EDX), X-Ray Photoelectron Spectroscopy (XPS), Transmission electron Microscopy (TEM). The frequency dependence of dielectric parameters in the range varying from 75 kHz to 5 MHz at room temperature has been explored. The variation of the a. c. conductivity, dielectric constant and loss factor with frequency were investigated. The loss tangent and dielectric constant exhibited a decreasing behaviour with increasing frequency. The samples having low values of loss at higher frequency indicate that these synthesised samples can be employed in high frequency applications. The nanocomposite samples exhibit improved electrochemical properties than their components. They were used as electrode materials of energy storage devices and found to deliver improved specific capacitance and cycling stability. The synthesised samples were found to exhibit high values of power and energy density. The nanocomposite sample (with 40% NiO) has lowest value of charge transfer co-efficient indicating the anodic current is dominant. •Co3O4–NiO nanocomposites series have been successfully prepared by a low-cost,facile and cost effective sol-gel ultrasonication route.•Dielectric analysis of nanocomposites indicates their potential application in energy storage field.•The electrochemical studies suggest that Co3O4–NiO nanocomposites have good cyclic stability and rate capability.