Fabrication of metal-organic framework based electrodes of MnCo₂-MOF-CoMoO₄ and Bi-MOF/AC nanocomposites for asymmetric supercapacitor

In this study, MnCo₂-MOF-CoMoO₄·nH₂O (RCME-CMO) and Bi-MOF/AC composites were prepared via reflux condensation and solvothermal method, respectively. This study explored the synergy between the distinct morphologies and charge densities of MOFs and MOs, and their impact on the electrochemical performance when combined into a composite. Crystal structure, functional group, surface area, thermal analysis, morphology and composite structure of RCME-CMO were investigated by using XRD, FT-IR, BET, TGA, FE-SEM and HR-TEM techniques, respectively. The nanosheet-RCME-CMO-nanorod composite exhibited excellent electrochemical performance over the RCME and CMO, a high specific capacitance of 420 F g⁻¹ at a current density of 5 mA cm⁻², with an outstanding rate capability of 85 %, though the current density increased to 3.6 times. The RCME-CMO nanocomposites retain an initial capacitance of 43.5 % over 10,000 cycles at 20 mA cm⁻². The solid-state asymmetric supercapacitor RCME-CMO//Bi-MOF/AC device was assembled using PVA-KOH gel electrolyte to check the practical applicability. This device achieved a specific capacitance of 206.51 F g⁻¹ and an outstanding energy density of 56.2 Wh kg⁻¹ at a power density of 875 W kg⁻¹ at a current density of 5 mA cm⁻². The exceptional performance of this supercapacitor demonstrates the efficacy of MOF-based composites in advanced energy storage electronics.