Graphene's role in enhancing Fe3O4 nanofibers: a comparative exploration of room temperature impedance characteristics and EMI shielding performance
Abstract
In this work, an electrospinning technique was used for the fabrication of nanofibers to examine the structural, electrical, and EMI shielding characteristics of pure Fe3O4 and Fe3O4-graphene (Fe3O4-Gr) nanofibers, exploring the potential contribution of graphene to the overall performance of Fe3O4. A consistent fibrous morphology with an average diameter of 62 nm was shown in field emission scanning electron microscopy (FE-SEM) analysis of the Fe3O4 nanofibers. However, the addition of graphene resulted in few aggregated fibers with an average diameter of 68 nm, which was slightly larger than that of pure Fe3O4 nanofibers. X-ray diffraction (XRD) pattern confirms that the spinel structure of pure Fe3O4 was retained in pure Fe3O4 and Fe3O4-Gr nanofibers. For both these nanofibers, impedance spectroscopy results showed a single semicircular response, indicating bulk relaxation processes. Fe3O4-Gr nanofibers exhibited greater bulk resistance at room temperature owing to the increased polarization effects introduced by graphene's conductive pathways. This effect was observed in the modulus plane plots, where Fe3O4-Gr stored more energy as graphene enabled charge movement and changes in dielectric relaxation. Compared with Fe3O4, Fe3O4-Gr nanofibers showed stronger polarization and higher dielectric constants, with two distinct relaxation peaks in the dielectric constant and tangent loss graphs. As per EMI shielding studies, Fe3O4-Gr nanofibers were better than pure Fe3O4 in terms of total shielding effectiveness (SET), mainly because graphene's conductive network helped increase the absorption component (SEA).