Core-shell nanowires comprising silver@polypyrrole-derived pyrolytic carbon for high-efficiency microwave absorption

Reasonable design of composition and microstructure of carbon nanomaterials can significantly enhance their electromagnetic energy conversion, which provides new strategies for expanding their application in the field of microwave absorption. In this study, core-shell nanowires, silver nanowires (AgNW) wrapped by polypyrrole-derived carbon shells (PPyC), have been successfully acquired through in situ polymerization of pyrrole monomers on the surface of AgNW and following carbonization in vacuum atmosphere. Composition, microstructure and microwave absorption properties of the produced hybrid nanowires are characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy and vector network analyzer, respectively. The heterostructured AgNW@PPyC nanowires present increased electrical conductivity and high aspect ratio due to the incorporation of AgNW, which activates multiple loss mechanisms including interfacial polarization, dipole polarization and related relaxation to achieve desirable microwave absorption performance. The AgNW@PPyC nanowires exhibited a minimum reflection loss value of -38.60 dB at the frequency of 10.30 GHz with the thickness of 2.57 mm and an effective absorption bandwidth of 3.53 GHz in the X-band (85%). The core-shell AgNW@PPyC nanowires with tunable composition and unique nanostructure are promising for realizing highly-efficient microwave absorption performance of carbon materials.