Magnetic nanoparticle-modified hollow double-shell SiC@C@FeCo with excellent electromagnetic wave absorption

Integrated micro and nanostructures, heterogeneous components, defects, and interfaces is the way to develop high-performance microwave absorbing materials. However, there still needs to be more precise experimental routes and effective validation. In this work, by a continuous process of vacuum sintering, hydrothermal, and carbon thermal reduction, magnetic FeCo nanoparticles were successfully embedded on the hollow double-shell mesoporous SiC@C surface, thus solving the challenges of a single component loss mechanism. The hollow double-shell nanostructure introduces air to enhance impedance matching while significantly reducing the density of the material. The extensive defects and heterogeneous grain boundaries effectively enhance the polarization loss capacity. The magnetic loss mechanism introduced by the magnetic particles effectively improves the impedance matching properties of the material. The synergy of these multiple advantages has enabled the SCFC2-8 (here SiC@C@FeCo is abbreviated to SCFC, 2 represents the initial metal ion content, and 8 represents the hydrothermal time) sample to achieve an adequate absorption bandwidth of 6.09 GHz at 2.0 mm. With a minimum reflection loss of −60.56 dB, the absorption bandwidth can cover the entire C, X, and Ku bands by adjusting the matching thickness (1.3–4.0 mm). This work provides a valuable paradigm for the deeper exploitation of microwave absorption potential and guides the development of other high-performance materials.