Lightweight and High-Performance Microwave Absorbing Heteroatom-Doped Carbon Derived from Chicken Feather Fibers

Doped material is an innovation in developing the lightweight microwave absorbing material. Herein, heteroatom-doped carbon is synthesized by pyrolysis of chicken feather fibers (CFFs) in the temperature range of 400-1400 degrees C. The synthesis method exhibits that poultry waste is more nature-friendly as no external hazardous dopants are used during pyrolysis, and it has a much lower cost. The morphology and structural characteristics have been studied via SEM, AFM, TEM, XRD, Raman, and XPS. The density of surface chemical states, defects, roughness, and structural property are found to vary significantly with pyrolysis temperature. The electromagnetic properties of CFF/epoxy composites have been studied in the frequency range of 8.2-12.4 GHz (X band). In addition, the correlations between pyrolysis temperature and absorption properties are established. High absorption properties at temperature >= 800 degrees C are attributed to the large fraction of heteroatoms, defects, surface roughness, and high porosity. In addition, the CFF pyrolyzed at 1400 degrees C is further activated with potassium hydroxide that results in numerous porous morphologies with large surfaces. This optimized porous CFF illustrates substantial absorption efficiency corresponding to the absorber thickness of 1.68 mm and RL of -44.6 dB (99.99% microwave absorption), which exhibits a broad -10 dB (90% absorption) bandwidth that shares 52.9% of the entire X band frequency width. The strong microwave absorption originates from defect polarization, electric/dipolar polarization, interfacial polarization, and 3D porous structure. The porous 3D architecture improves the impedance matching and can generate multiple reflections and scattering of electromagnetic waves, which attenuate microwave waves largely. This work suggests that the heteroatom-doped carbon derived from CFF is a potential candidate to design a lightweight and efficient microwave absorber.