Facile synthesis of FeNi nanoparticle-loaded carbon nanocomposite fibers for enhanced microwave absorption performance.

• The FeNi/C nanofibers exhibited excellent microwave absorption performance with a minimum reflection loss of -57.15 dB and an effective absorption bandwidth of 4.0 GHz at 1.6 mm. • The FeNi/C nanofibers showed better electromagnetic microwave absorption performance than the single-component nanofibers and pure carbon fibers. • The superior performance of FeNi/C nanofibers can be attributed to the formation of abundant heterojunction interfaces, a cross-linking conductive network, and multidimensional magnetic components. The advantages of Fe, Ni metals and one-dimensional (1D) carbon materials are combined in this study using a simple method to prepare FeNi/C nanofibers for electromagnetic microwave (EM) absorption. The prepared FeNi/C nanofibers exhibit excellent EM absorption performance under dielectric/magnetic synergistic effect. At a frequency of 13.3 GHz, the minimum reflection loss (RL min) reaches -57.15 dB, and effective absorption bandwidth (EAB) is as high as 4.0 GHz (12.5–16.5 GHz), with a thickness and filling rate of only 1.6 mm and 30 wt.%, respectively. Analysis shows that the EM absorption performance of FeNi/C nanofibers far exceeds that of single-component nanofibers and pure carbon fibers, and the excellent EM absorption performance is due to its unique microstructure and excellent electromagnetic properties. The FeNi alloy loaded on carbon nanofibers forms rich heterogeneous interfaces, and the three-dimensional (3D) conductive network composed of 1D carbon fibers increases the migration path of electrons. In addition, FeNi alloy, as an impedance regulation factor, strengthens the dielectricity of the carbon matrix while providing multidimensional magnetism, achieving impedance matching. This work is thought to contribute to the promotion of emerging absorbers by providing a novel strategy for the development of new 1D magnetic carbon-based high-performance EM absorbing materials. [Display omitted] [ABSTRACT FROM AUTHOR]