Magnetic Nitrogen-doped carbon nanofibers containing homogeneously dispersed CoFe2O4 nanoparticles with lightweight and efficient microwave absorption performance

Homogeneously dispersed ultrafine CoFe2O4 nanoparticles embedded within N-doped carbon nanofibers (named as [email protected]) have been fabricated via electrospinning and following heat treatment procedures. The dielectric and magnetic parameters of [email protected]/paraffin wax composites are regulated through adjusting the concentration of CoFe2O4 to obtain good impedance matching and excellent microwave absorption (MA) properties. Benefiting from the unique structure involving CoFe2O4 @onion-like carbon nanospheres and 3D conductive NCNFs network, as well as the synergistic mechanism between ultrasmall magnetic CoFe2O4 nanoparticles and light mass dielectric NCNFs. The [email protected] exhibit outstanding MA properties at only 20 wt% filler loading and minimum reflection loss (RL) achieves −47.9 dB (surpass 99.9% MA) at 9.2 GHz with a thin thickness of merely 1.7 mm, and the corresponding effective absorption bandwidth (RL < −10 dB) achieves 5.4 GHz (6.5–11.9 GHz). Moreover, the effective absorption bandwidth (EAB) can be obtained in multiband (3.9–18.0 GHz) by adjusting the thickness of sample layer. Our work indicates that the appropriate incorporation of ultrafine CoFe2O4 nanoparticles encapsulated in NCNFs is a versatile and high-efficiency strategy to integrate lightweight and excellent properties of magnetic carbon-based absorbers.