Surface plasmon resonance-enhanced dielectric polarization endows coral-like Co@CoO nanostructures with good electromagnetic wave absorption performance

• The novel structure of coral-like Co@CoO causes strong surface plasmon resonance. • Surface plasmon resonance enhances the EM wave absorption property of Co@CoO. • Co@CoO-550 obtains good EM wave absorption at low loading and thin thickness. Geometry and microstructure are two of the most significant factors associated with the electromagnetic wave absorption performance. Here, novel coral-like Co@CoO nanostructures assembled by Co@CoO core–shell nanofibers are synthesized via versatile hydrothermal and reduction treatment processes. The as-prepared Co@CoO nanostructure has vast surface area, abundant interface and numerous dipoles, which generate empowered interfacial and dipole polarizations. Compared to the traditional cobalt absorbers, this new coral-like Co@CoO nanostructure give rise to strong surface plasmon resonance (SPR), resulting enhanced local electric field and further boosting the dielectric polarization in a great extent. The SPR-enhanced dielectric polarization endows coral-like Co@CoO with good electromagnetic wave absorption performance. Coral-like Co@CoO-550 with 25 wt% loading exhibit dual-peak electromagnetic reflection loss at −20.6 dB and −62.76 dB and effective absorption bandwidth at 3.60 GHz with a thickness of 1.65 mm.