Constructing and optimizing hollow bird-nest-patterned C@Fe3O4 composites as high-performance microwave absorbers

Rational design of microstructure and components provides an effective method to address the challenge of developing advanced microwave absorption (MA) materials. In this work, combining the preparation of the precursors (SiO2@RF) for the deposition of Fe-glycerate (Fe-G) nanosheets and in situ pyrolysis process, followed by removal of the SiO2 template, the bird-nest-patterned C@Fe3O4 (BN-HDCF) composites with hollow dual-shell structure are rationally constructed to obtain superior MA performance. The results demonstrate that the eddy effect is suppressed by lamellar Fe3O4 shell, which benefits the entrance of electromagnetic waves (EMWs) and the cavity and groove of bowl like carbon core could boost the attenuation of EMWs. Importantly, due to the integration of the synergistic effects and the multiple polarization loss as well as the improved impedance matching, the as-prepared BN-HDCF composites demonstrate excellent MA performance in view of both minimum reflection loss (RLmin, -80 dB) and effective absorption bandwidth (EAB, below -10 dB, 6.1 GHz) with a thickness of 2.23 mm, covering the full X band with a thickness of 3.1 mm. Such impressive MA performance lights the way to the fabrication of the hierarchical structure of advanced absorbents.

Automated summary

By rational design and structural construction, the bird-nest-patterned C@Fe3O4 (BN-HDCF) composites with hollow dual-shell structure were successfully prepared, demonstrating excellent microwave absorption performance.