Design and fabrication of cobalt and nickel ferrites based flexible electrodes for high-performance energy storage applications

Abstract

In this work, to enhance supercapacitor research performance, we have prepared two different types of ferrites as CoFe2O4 and NiFe2O4 nanoparticles by two different routes, such as co-precipitation followed by hydrothermal method and facile hydrothermal method for the first time. In order to study the structural, morphological, and elemental composition of the fabricated ferrite electrodes, various characterization studies have been carried out, such as XRD, Raman, FESEM, EDS, HRTEM, BET, and XPS analysis. N2 adsorption–desorption results reveal that the hydrothermal assisted NiFe2O4 electrode shows a high surface area (109.3 m2/g) and pore size (43.4 nm) than compared with CoFe2O4 (78.5 m2/g and 21.2 nm). The electrochemical studies have been carried out for the electrodes using 1 M H2SO4 as electrolyte and graphite sheet as a current collector through three-electrode and two electrode systems, respectively. A maximum specific capacitance of 466 F g−1 at a current density of 1 A g−1 and 280 F g−1 at a current density of 0.5 A g−1 were obtained for the nickel ferrite nanoplates prepared via one-step hydrothermal method using three-electrode and two electrode systems, respectively. Moreover, the assembled symmetric NiFe2O4 supercapacitor delivers a high energy density (10 Wh Kg−1) at 0.5 A g−1 and power density (2500 W Kg−1) at a current density of 5 A g−1. Besides, the NiFe2O4 symmetric supercapacitor device exhibits 100% of specific capacitance retention sustained up to 10,000 cycles and 99% of Columbic efficiency.