Morphological characterization and impedance spectroscopy study of porous 3D carbons based on graphene foam-PVA/phenol-formaldehyde resin composite as an electrode material for supercapacitors

Abstract

The design and fabrication of porous electrode materials is highly desirable for improving the performance of electrochemical supercapacitors (ECs) and thus, it is important to produce such porous materials in large quantities. In this study, we used a microwave method to produce porous carbonaceous materials designated as graphene foam/polyvinyl alcohol/formaldehyde (GF/PVA/F) and graphene foam-polyvinyl alcohol/phenol-formaldehyde (GF/PVA/PF) from graphene foam, phenol formaldehyde and polyvinyl alcohol (PVA). Scanning electron microscopy (SEM), Raman spectroscopy and Fourier-Transform Infrared Spectroscopy (FTIR) were used to characterize the surface morphology, structural defects and functional groups of the materials respectively. Based on these porous materials, the two symmetrical ECs fabricated exhibited a specific capacitance in the range of 0.62–1.92 F cm−2, phase angles of −81° and −84° and resistor–capacitor (RC) relaxation time constants of 4 and 14 seconds. The physicochemical properties of the electrolyte ion (diffusion) and its influence on the capacitive behavior of the porous materials were elucidated. These encouraging results demonstrate the versatile potential of these porous materials (GF/PVA/F and GF/PVA/PF) in developing high energy storage devices.