Fabrication of core-shell Co@HCN@PANI composite material with enhanced electromagnetic wave absorption

A core-shell Co@ hollow carbon nanospheres @ polyaniline nanocomposite for EMW absorption was constructed via soft template, switching liquid phase transport and in-situ polymerization method. Polarization at the interface of Co, HCN shell and PANI enhances the polarization loss of core-shell Co@HCN@PANI nanocomposite. The dense conductive network formed by PANI endows the material with a more significant electronic conduction loss mechanism. Multi-layer heterogeneous interfaces in core-shell structures and multi-centers in PANI molecular chains enrich the polarization relaxation loss mechanism. The natural resonance of magnetic Co at high frequency bands and eddy current thermal effect at low frequency bands ensure the stable magnetic loss of the material. Good impedance matching and enhanced attenuation coefficient further improve the microwave absorption performance of the nanocomposite. Consequently, a minimum reflection loss of −43.63 dB and an effective absorption bandwidth of 9.75 GHz (8–17.75 GHz) are obtained at a matched thickness of 2.8 mm.