Ultra-thin Ni@nitrogen-doped polyaniline-derived carbon composites with broadband electromagnetic wave absorption

Ni@nitrogen-doped polyaniline-derived carbon composite (NC-n) was prepared through in situ polymerization and pyrolytic reduction for electromagnetic wave (EMW) absorption over 2–18 GHz. With polyaniline as the carbon source through carbonization, nitrogen doping was successfully realized, leading to enhanced interfacial polarization, dipole polarization, and defect polarization. In addition, the production of metallic nickel resulted in eddy current loss and magnetic resonance loss, enabling multiple absorption mechanisms. The impedance matching of the NC-n could be optimized by adjusting the composition, which results in a reduction in the reflection EMW at the surface of the materials. Specifically, a reflection loss of −61.93 dB was achieved at a thickness of 1.72 mm, together with an effective absorption bandwidth of 5.68 GHz (12.08–17.76 GHz) at 1.80 mm. This strategy can be used as a reference to design high performance composite EMW absorbers.