Improvement of multiple attenuation characteristics of two-dimensional lamellar ferrocobalt@carbon nanocomposites as excellent electromagnetic wave absorbers

Abstract

The lightweight carbon skeleton compounded with magnetic nanoparticles as excellent electromagnetic wave absorbers has attracted much attention considering their strong dielectric loss and magnetic loss, as well as the optimized impedance matching. However, the conventional method of compounding magnetic metals with carbon materials usually leads to the inevitable aggregation of magnetic nanoparticles, resulting in poor microwave attenuation characteristics. In this study, two-dimensional (2D) lamellar carbon matrix ferrocobalt (Co_xFe_1−x/C) nanocomposites are prepared using sodium chloride (NaCl) as a hard-template. By regulating the relative contents of Co and Fe in the nanocomposites, the 2D lamellar carbon skeleton with uniformly dispersed magnetic nanoparticles can be obtained successfully. Furthermore, the existence of a variety of metal and alloy phases promotes the generation of multiple attenuation characteristics. As a result, the Co_0.9Fe_0.1/C exhibits a broad effective absorption bandwidth of about 5.4 GHz at a thin thickness of only 1.65 mm. The excellent electromagnetic wave absorption can be attributed to the formation of a 2D lamellar structure and the uniform distribution of magnetic nanoparticles being conducive to the enhancement of polarization loss including dipole polarization loss and interfacial polarization loss. Considering that, the 2D lamellar Co_0.9Fe_0.1/C nanocomposite is promising to be a candidate for excellent electromagnetic wave absorbers.