Supercapacitor properties of Ni2+ incrementally substituted with Co2+ in cubic spinel NixCo1-xFe2O4 nanoparticles by sol-gel auto combustion method

Abstract

The nanoparticle powder of Ni1-xCoxFe2O4 (x = 0.00, 0.25, 0.50, 0.75, 1.00) spinel ferrite was successfully prepared by the sol-gel auto-combustion method. The synthesized nanomaterials were used to prepare spinel ferrite supercapacitor electrode material. The structured phase of prepared nanoparticle powders was studied using XRD which shows the prepared sample consists of nanocrystalline single phase, with cubic spinel ferrite. Furthermore, using FESEM surface morphology of prepared samples was investigated. Ni1-xCoxFe2O4 nanoparticles spinel ferrite structure was verified by FT-IR, which detected distinctive vibrational bands at octahedral and tetrahedral locations.The spinel ferrite type materials are good active electrode materials. In this study, the prepared Ni1-xCoxFe2O4 electrode material is used as cathode material for supercapacitor. The electrochemical behavior of prepared samples was studied and compared by using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 M KOH electrolyte. An electrochemical measurement study of prepared samples shows excellent performance and desirable cycling stability for supercapacitors. The prepared Ni0.5Co0.5Fe2O4 spinel ferrite gives the highest specific capacitance of 1282 F/g at a current density of 5 mA/cm2 with corresponding energy density of 30 Wh/kg and power density of 301 W/kg. Also, they exhibited outstanding cycling stability for 5000 cycles with 91.24 % capacity retention.