MOF-Derived Flower-like MnCo2O4.5 and Co-Mn-ZIF@rGO Composite as Efficient Electrodes for High-Performance Aqueous Asymmetric Supercapacitors

Recently, porous metal–organic frameworks (MOFs) have attracted considerable interest as electrode materials for supercapacitors. However, their low electrical conductivity and stability hinder their capacitance and practical applications. To address these challenges, this study aims to enhance the electrochemical performance of MOFs by fabricating MOF-derived MnCo2O4.5 and Co-Mn-ZIF@rGO nanocomposites. Herein, Co–Mn-ZIF is first synthesized using a simple solution-based method, followed by annealing to form 3D microflower-like MOF-derived MnCo2O4.5 composed of interconnected 2D nanoflakes. As a result, it exhibits a high specific capacity (Cs) of 620.9 C/g at a current density of 1 A/g and exceptional cyclic stability of 94% after 10,000 cycles. Similarly, Co-Mn-ZIF@rGO, prepared by a solution method followed by annealing, exhibits a high specific capacitance (Csp) of 650.2 F/g at a current density of 1 A/g and 89% cyclic stability after 10,000 cycles. Furthermore, an aqueous asymmetric supercapacitor (AASC) device was fabricated using MOF-derived MnCo2O4.5 and Co-Mn-ZIF@rGO as the positive and negative electrodes, and 6 M KOH as the electrolyte. The AASC device demonstrated a high potential window of 1.8 V and a maximum energy density of 55.1 Wh/kg at a power density of 13,500 W/kg. These AASC devices exhibit ∼ 30% greater capacitance compared to existing MnCo2O4.5-based devices. Additionally, it exhibited an excellent cyclic stability of 92.6% of its initial capacitance after 10,000 cycles. These exceptional electrochemical performances make both electrodes highly efficient and promising for next-generation energy storage applications.