Synthesis of carbon/SiO2 core-sheath nanofibers with Co-Fe nanoparticles embedded in via electrospinning for high-performance microwave absorption

As an excellent microwave absorption material, the in-depth study of carbon-based nanofibers’ absorbing mechanism is of great significance for subsequent applications. In this paper, carbon/SiO2 core-sheath nanofibers with Co-Fe nanoparticles embedded in were synthesized by electrospinning and carbonization. The morphology, microstructure, magnetic properties, and microwave absorption performance of the composite nanofibers were characterized in detail. The results show that the maximum reflection loss (RL) could reach to −59.6 dB, and the maximum effective absorption bandwidth (RL <  −10 dB) achieved 4.6 GHz with only 1.43 mm thickness. It is indicated that the introduction of SiO2 improved the impedance matching, and formed a large number of heterogeneous interfaces with carbon nanofibers and Co-Fe nanoparticles, resulting in the interfacial polarization. Co-Fe nanoparticles could enhance the magnetic loss by small size effect, while the graphite lattice was damaged to a certain extent, causing the dipole polarization. This work provides an effective idea for the synthesis and performance optimization of high-performance microwave absorption materials. The high-performance microwave absorption of carbon/SiO2 core-sheath nanofibers with Co-Fe nanoparticles embedded in is caused by conductive loss, interfacial polarization, dipole polarization and magnetic loss.