Investigation of electrochemical performance of sol-gel derived MgFe2O4 nanospheres as aqueous supercapacitor electrode and bi-functional water splitting electrocatalyst in alkaline medium

Abstract Herein this work, we have used the sol-gel chemical synthesis method to prepare spherical shaped MgFe2O4 nanoparticles having size 45–50 nm. Using 1 mol L−1 Sodium Perchlorate (NaClO4) electrolyte, a capacitance of 61 F/g, a capacitance retention of 82.91% (after undergoing 1000 cycles), and an energy density of 41 Wh/kg have been achieved. Using 1 mol L−1 Magnesium Perchlorate (Mg(ClO4)2) as electrolyte, a capacitance of 43 F/g, a capacitance retention of 82.15%, and an energy density of 29 Wh/kg have been realized. Furthermore, MgFe2O4 nanospheres exhibited an overpotential (η) = 1.09 V, a Tafel slope (b) = 317 mV/dec in regard to alkaline Oxygen Evolution Reaction (OER) electrocatalyst. It also achieved η = 402 mV and b = 241 mV/dec in regard towards alkaline Hydrogen Evolution Reaction (HER) electrocatalyst. These results signify the suitability of MgFe2O4 nanoparticles for high energy density aqueous supercapacitor and water splitting electrocatalyst applications.