Preparation of hierarchical core-shell C@NiCo2O4@Fe3O4 composites for enhanced microwave absorption performance

To obtain excellent microwave absorption (MA) performance, elaborately designing dielectric-magnetic hierarchical C@NiCo2O4@Fe3O4 composites were successfully synthesized by a two-step route. Both the sea urchin-like structure generated by NiCo2O4 and the void space in the core originated from the decomposition of carbon spheres were beneficial structural characteristics for the attenuation of electromagnetic waves. The impedance matching as a result of the addition of uniformly Fe3O4 nanoparticles was a strong contributor to the excellent MA property of C@NiCo2O4@Fe3O4 composites. The minimum reflection loss (RL) value of it reached −43.0 dB at 13.4 GHz with a thickness of 3.4 mm, which was much higher than that of C@NiCo2O4 or pure NiCo2O4.