Self-Standing MOF-Derived Co@SiCnw Nanocomposite Aerogel with a Hierarchical Microstructure for Highly Effective and Wideband Electromagnetic Attenuation

To meet the requirements of lightweight and wideband attenuation for advanced electromagnetic (EM) absorption materials, the combination of both MOF composition and hierarchical structural design was applied as the strategy to prepare the MOF-derived Co@SiC nanowire (Co@SiCnw) nanocomposite aerogel. The hierarchical and laminated structures with multiple Co@SiCnw layers were constructed via a mixed growth-assisted freeze-drying and calcination process. The ultralightweight Co@SiCnw presents a low density of 0.11 g/cm3. With abundant second-phase polarization interfaces and enlarged EM wave attenuation channels to enhance dielectric and conductive loss, the optimized Co@SiCnw offers a minimal reflection loss (RLmin) of −61.4 dB at 10.0 GHz (2.64 mm) and an effective absorption bandwidth (EAB) as wide as 7.44 GHz with a sample thickness of only 2.16 mm. Furthermore, multifunctionalities, including low density, thermal insulation, and self-standing, were demonstrated for Co@SiCnw, making it a high-performance and practical microwave absorption material.