Enhanced N-Doping Effect on the Electromagnetic Wave Absorption Performance of Fe ₃ C/Fe@Carbon Foam

The anionic doping, particularly N-doping, has emerged as a common approach for developing superior electromagnetic wave absorbing (EWA) materials. In order to further modulate the electronic transport properties, hexagonal boron nitride (h-BN) was introduced as a precursor for enhanced doping of N atoms. Instead of the conventional mixing method, which results in the loss of the flake-like nature of the h-BN, h-BN nanosheets exfoliated from h-BN powders were introduced via electrostatic self-assembly to enable the mass production of homogeneous N-doped Fe3C/Fe@carbon foam. The nitrogen dopants from h-BN created defects in the Fe3C/Fe and the carbon matrix, thus creating dipole polarization centers in alternating electromagnetic fields. Enhanced N-doping results in improved impedance matching and a significant dielectric loss in the composites. Consequently, the N-doped Fe3C/Fe@carbon foam achieved a minimum reflection loss (RLmin) of −53.96 dB and an effective absorption bandwidth (EAB) of 6 GHz at a thickness of 2.4 mm. This research proposes a novel strategy for enhancing the electromagnetic attenuation capabilities of N-doped iron–carbon composites, offering valuable insights into the design of next-generation advanced electromagnetic wave absorbers.