Natural Stabilizer-Assisted Sol-Gel Synthesis of Medium-Entropy Spinel Ferrite: Structural and Electrochemical Insights for Supercapacitor Applications

Abstract

Engineering of different cation spinel ferrites is an effective way to improve their structural, physicochemical and electrochemical properties. The synergetic effect of the different metal ions in their ferrite lattices has an important effect on their structural stability, electronic conductivities and improvement of their ion mobility. Hence these materials become suitable candidates for advanced energy storage devices of super-capacitors. In the present study, (MnCoNiZn)Fe2O4 spinel ferrite was synthesized by sol-gel route using albumen (egg white) as natural stabilizer as well as chelating agent for the preparation of ferrite. The formation of single-phase cubic spinel structure with space group of Fd-3m has been established by XRD studies. The morphology analysis using FESEM and HRTEM revealed well-defined, uniformly distributed pyramidal-shaped particles, confirming the controlled growth achieved by the synthesis route. The electrochemical evaluation was carried out in three electrode configuration using aqueous 2M KOH electrolytes. The prepared ferrite exhibited a specific capacitance as high as 408.18 F/g at a significantly high current density of 4 A/g in charge-discharging, highlighting its superior charge storage capacity. The coulombic efficiency has been found to be 91.6% upto 1500 continuous charge-discharge cycle which reveal excellent reversal behaviour. Overall, this study establishes albumen-assisted sol-gel synthesis as a non-toxic stabilizer and effective strategy for producing medium-entropy spinel ferrites, emphasizing their potential as sustainable and high-performance electrode materials for superior performance supercapacitor applications.