Novel Lightweight and Efficient Biomass Porous Carbon Electromagnetic Waves Absorbing Material Derived from Modified Sorghum Straw

A novel lightweight and efficient biomass porous carbon composite absorbing material was prepared by using sorghum straw as the absorbing matrix and combining the magnetic precursor acetylacetone nickel (NA) with Polymer-derived ceramics (PDCs). The results showed that when the doped content of NA was 2 % and the filler content was 30 %, the sample exhibited strong response to electromagnetic waves (EMW). The minimum reflection loss (RL min ) 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 (13.79-18 GHz). In addition, the RL min 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 Ni 2 Si effectively adjusted the impedance matching of the sample, and jointly regulated the conductivity with graphite carbon. The biomass porous carbon material (BPCs) matrix with large specific surface area, CNTs and Ni 2 Si provided a large number of heterogeneous interfaces, which promoted interfacial polarization and dipole polarization. In addition, the introduction of Ni endowed the sample magnetic loss, and a variety of loss mechanisms made the material have strong absorbing properties.