Bimetallic MnFe₂-MOF and Its Derived MnFe₂O₄ Nanostructures for Supercapacitive Applications

Abstract

At present, supercapacitors (SC) based on metal−organic frameworks (MOFs) have gained a lot of attention in energy storage and conversion applications because of their fascinating properties such as low densities, variable chemical functions, high surface area, and porosity. The manuscript covers the synthesis of bimetallic MOF and MOF-derived ferrites via a chemically wet route and heat treatment process, respectively. The prepared electrode material was utilized to construct the asymmetric supercapacitor devices. The MnFe 2 -MOF electrode exhibits outstanding electrochemical properties over the derived MnFe 2 O 4 along with high reversibility, fast kinetics, low charge transfer resistance (2.9 Ω), and an excellent specific capacitance of 1226 F g −1 at a current density of 1 mA cm −2 with a superb cyclic stability of approximately 90.74% of the initial capacitance even after 5000 subsequent charge−discharge cycles. Additionally, an asymmetric device was fabricated to confirm the practical viability of MnFe 2 -MOF as an anode and activated carbon as a cathode. The fabricated asymmetric device demonstrates an excellent specific capacitance of 91.87 F g −1 at a 1 mA cm −2 current density with a specific energy of 32.67 Wh kg −1 and a high specific power of 1000 W kg −1 . Simultaneously, the fabricated asymmetric supercapacitor (ASC) device unveils exceptional cyclic stability (85.25%) and Coulombic efficiency (96.81%) at a higher current density of 8 mA cm −2 even after 10,000 charge−discharge cycles. These perceptible results based on MOF-derived ferrite nanostructure can make it a significant electrode material for supercapacitor application in today's technological applications.