Fabrication of Novel Cu-Embedded Core-Shell Carbon Nanofibers With High Electrical Conductivity via Coaxial Electrospinning

Abstract

Electrospun carbon nanofibers (CNFs) have gained an enormous importance due to their unique properties. However, the limitation of electrical conductivity has restricted their applications. In this paper, copperembedded core-shell CNFs were prepared via coaxial electrospinning process followed by heat treatment. The effect of press on surface structural and electrical properties of electrospun nanofiber mats was elaborately studied by using various loads. The morphology and structures of pressed CNFs were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The four-point probe technique was used to measure the surface electrical conductivity of CNFs. Based on results, the applied press on nanofibers slightly deforms the graphite-like framework and increases the defective structure of CNFs. The increase of these defects is accompanied by an enhancement of quaternary nitrogen (QN) amount in CNFs, indicating that QN might exist in the graphite-like lattice. These effects become more pronounced with increasing press on nanofibers. The electrical conductivity of CNFs significantly increases while the applied load gradually grows, reaching about 100.7 Scm- 1 at 5 tons. The quaternary nitrogen in the graphite layer generates an extra electron for the delocalized It-system, causing an increase in the vibration of It-system, thus improving the electrical conductivity.