A crosslinked coral-like Co@CoO/RGO nanohybrid structure with good electromagnetic wave absorption performance.

The combination of magnetic and dielectric materials followed by appropriate structure design is an effective approach to achieve high electromagnetic wave absorption properties. Here, crosslinked Co@CoO/reduced graphene oxide nanohybrids (CCRGO) were fabricated via a simple three-step method. The experimental results show that compared with previous works, the as-prepared CCRGO nanohybrids achieve higher electromagnetic wave absorption and broader effective bandwidth at a lower filler loading. The electromagnetic parameters and electromagnetic wave absorption performance could be apparently adjusted by controlling the adding content of graphene oxide (GO) and the reduction temperature. Among a series of samples, CCRGO3-650 nanohybrid yields the best electromagnetic wave absorption performance benefiting from the proper GO addition and reduction temperature. At a filler loading of 20 wt%, the maximal reflection loss reaches to -64.67 dB at a thickness of 2.53 mm and the effective bandwidth below -10 dB covers the whole X band at a thickness of 2.51 mm. The good performance may be ascribed to the advantages of the dielectric and magnetic component as well as the special crosslinked structure, which triggers a synergistic absorption mechanism including multiple reflection/scattering, interface polarization, dipole polarization, conductive loss, eddy current loss, exchange resonance in the electromagnetic wave dissipation process. The good electromagnetic wave absorption performance affirms the potential application of CCRGO nanohybrids in the field of stealth materials.