Facile Synthesis of Bimetallic Oxides (ZnMn ₂ O ₄ ) From MOFs for Enhanced Asymmetric Supercapacitor Performance

The synthesis of metal oxides using metal–organic framework (MOF) templates allows precise control over surface morphology and tailorable chemical functionality, thereby facilitating the fabrication of highly porous and crystalline structures that are essential for high‐performance energy storage devices such as supercapacitors (SCs). This study reports the development of bimetallic oxide ZnMn 2 O 4 materials derived from MOFs through a facile solvothermal synthesis process followed by calcination, aiming to enhance their performance in an asymmetric supercapacitor device. According to the X‐ray diffraction (XRD) analysis, the material exhibits a tetragonal crystal structure with the space group I4 1 / amd . Furthermore, Fourier‐transform infrared spectroscopy (FTIR) and Raman spectra confirm the presence of metal–oxide bonds within the material. The scanning electron microscopy (SEM) and high‐resolution transmission electron microscopy (HRTEM) analyses indicate the presence of a microspherical morphology, while X‐ray photoelectron spectroscopy (XPS) confirms that Zn exists in the +2, and Mn in the +3 oxidation state in the ZnMn 2 O 4 material. The electrochemical analysis of the ZnMn 2 O 4 electrode was assessed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) within a 2 M KOH electrolyte. At a scan rate of 10 mV/s, the ZnMn 2 O 4 electrode exhibited a specific capacitance of 537 F/g, while at a current density of 1 A/g, it provided 558 F/g. The electrode displayed excellent cycle stability, with a capacitance retention of 95.90% and a Coulombic efficiency of 99.95% after 1000 cycles at a current density of 3 A/g. The as‐fabricated asymmetric supercapacitor device (ZnMn 2 O 4 //activated carbon) showed 69.90% capacitance retention and 72.65% Coulombic efficiency after 5000 cycles at a current density of 3 A/g, while achieving energy and power densities of 50.94 Wh/kg and 800 W/kg, respectively, within a 1.6 V potential window. These findings may contribute to the development of advanced supercapacitors based on bimetallic metal oxide nanostructures derived from MOFs.