Biomass-derived Fe/C composites for broadband electromagnetic wave response

Magnetic metal modified carbon-based composites synthesized through chemical methods have shown great potential in the field of electromagnetic wave (EMW) absorption. Biomass-derived carbon, as an alternative to traditional carbon sources, has better economic and environmental benefits. In this work，we embedded magnetic iron ions in dried agaric through multi-effect adsorption and obtained ripple-like Fe/C composites after high-temperature annealing. The effective absorption bandwidth (EAB) of Fe/C composites can reach 6.3 GHz (11.5–17.8 GHz) at 2.5 mm, achieving broadband electromagnetic response. The excellent performance can be attributed to the ripple-like carbon, which enhances the transmission path of EMW in the absorber. On the other hand, the uniform loading of Fe nanoparticles on biomass-derived carbon promotes the interface polarization and dipole polarization and coordinates the impedance matching of the composites. This study provides a reference for the design and construction of efficient biomass-derived magnetic carbon-based absorbers. [Display omitted] •Fe/C composites have been synthesized using biomass-derived method.•Fe/C composites exhibit an effective bandwidth (RLmin ≤ −10 dB) of 6.3 GHz with the thickness of 2.5 mm.•The great absorption performance of Fe/C composites stems from proper impedance match and boosted dielectric-magnetic loss.