Novel lightweight and efficient electromagnetic waves absorbing performance of biomass porous carbon/polymer-derived composite ceramics

The biomass porous carbon (BPC)/polymer-derived composite ceramics with lightweight and efficient electromagnetic waves (EMW) absorbing performance was prepared by using sorghum straw as the absorbing matrix and combining the magnetic precursor acetylacetone nickel (NA) with polysilazane (PSZ). The results showed that when the doped content of NA was 2% and the filler content was 30%, the sample exhibited strong response to EMW. The minimum reflection loss (RLmin) reached − 69.44 dB at the thickness of only 1.33 mm, and the effective absorption bandwidth (EAB) at 1.49 mm was 4.27 GHz (13.73–18 GHz). In addition, the RLmin at 4.22 m was −45.80 dB at low frequency. The EAB between 4.20 mm and 5 mm remained above 2.4 GHz and the widest reached 2.48 GHz. The in-situ generated Ni2Si effectively adjusted the impedance matching of the sample, and jointly regulated the conductivity with graphite carbon. The biomass porous carbon material matrix with large specific surface area, CNTs and Ni2Si provided large numbers of heterogeneous interfaces, which promoted interfacial polarization and dipole polarization. In addition, the introduction of Ni endowed magnetic loss, and a variety of loss mechanisms improved the EMW absorbing properties of the Ni/PDCs/BPCs composites.