Carbon nanofibers embedded with Fe–Co alloy nanoparticles via electrospinning as lightweight high-performance electromagnetic wave absorbers

As a lot of electromagnetic pollution and interference issues have emerged, to overcome electromagnetic interference, prevent electromagnetic hazards, and develop new high-performance electromagnetic wave (EMW) absorbers have become a significant task in the field of materials science. In this paper, a three-dimensional (3D) carbon nanofibers network with core–shell structure, embedded with varied molar ratios of iron and cobalt (4:0, 3:1, 2:2, 1:3, 0:4), was effectively synthesized (Fe/Co@C-CNFs) via electrospinning. The phase, microstructure, magnetic and EMW absorption properties were studied. It is discovered that Fe/Co@C-CNFs doped with iron: cobalt = 1:1 have excellent EMW absorption capacity. When the matching thickness is 1.08 mm, the minimum reflection loss (RL) value is − 18.66 dB, while the maximum effective absorption bandwidth (EAB) reaches 4.2 GHz (13.9–18 GHz) at a thickness of 1.22 mm. This is owing to the absorbers' superior impedance matching and multiple reflections as well as the conductivity, dielectric, and magnetic losses of carbon nanofibers embedded with Fe–Co alloy particles. In addition, the radar cross section (RCS) of the absorbers has been calculated by CST Studio Suite, showing that the absorbing coating can effectively reduce the RCS at various angles, especially for Fe/Co@C-CNFs doped with iron:cobalt = 1:1. These findings not only provide new insights for the preparation of lightweight and high-performance electromagnetic wave absorbers, but also contribute to energy storage and conversion.