Synergic effect of flower-like Cu-based metal-organic framework/graphene nanostructures on electrochemical performance of supercapacitors

Document Type : Original Article

Authors

1 Department of Metallurgy and Materials Science, Imam Khomeini International University, Qazvin, Iran.

2 Department of Chemistry, Sharif University of Technology, Tehran, Iran

Abstract

Metal-organic frameworks (MOFs) have been used as electrode materials in supercapacitors (SCs) due to their high specific surface area and the suitability of porosity. However, using single-component MOFs in SCs results in poor electrical conductivity, insufficient stability, and poor mechanical properties, and thwart the effect of high capacity and efficient performance. In this paper, to improve the electron transfer rate and utilize the specific surface of MOFs, graphene was combined by copper-MOF via hydrothermal in-situ synthesis. To prevent agglomeration, graphene (0, 2.5, 5, and 10 wt%) was added during the synthesis. To characterize the structure of nanocomposites, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FESEM) analysis were used. Electrochemical tests such as cyclic voltammetry, electrochemical impedance, and repeatability behavior were performed to study the supercapacitor behavior. The electrodes made by graphene and the copper-based MOFs had the specific capacity of 217 and 187 F/g in a 6M KOH electrolyte, respectively, while their composite had the specific capacity of 550 F/g. As a result, the synergic effect in the composite and enhanced electrical conductivity of MOFs resulted in greater availability of porosities and increased total storage capacity.

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