A novel CNTs/Co9S8 microsphere composites with three-dimensional network structure for efficient electromagnetic wave absorption

A novel CNTs/Co₉S₈ microsphere nanocomposites with a three-dimensional network structure were synthesized via hydrothermal methods, which exhibited excellent electromagnetic wave absorption (EWA) properties. The physical phase composition, microscopic morphology, EWA performance and related mechanisms were deeply discussed. The incorporation of Co₉S₈ nanoparticles formed a three-dimensional conductive network within the CNTs matrix, significantly increasing the heterogeneous interfacial area, thereby enhancing both conductive and interfacial polarization losses. Additionally, the three-dimensional network structure not only enhances the mechanical stability of the material, but also provides multiple reflection and scattering paths for electromagnetic waves (EWs), which significantly improves the energy dissipation efficiency of EWs. Thanks to the synergistic effects of optimized attenuation and favorable impedance matching, the composites demonstrated excellent EWA performance, with a minimum reflection loss of −50.1 dB and an effective absorption bandwidth of 2.56 GHz at a thickness of 2.49 mm. Moreover, the composites reduced the radar cross sectional area, which is an important safeguard for their practical application in stealth technology. This work offers new insights and a theoretical basis for designing three-dimensional EWA materials.