Interface-engineered MOF-derived CoS/C nanofibers for efficient microwave absorption and radar-scattering suppression

CoS/C nanofibers were constructed via MOF-template-assisted interfacial engineering. • Rich CoS/C interfaces and defect sites enable strong broadband microwave attenuation. • Gradient periodic structures further regulate multiband absorption and RCS reduction. Developing fibrous microwave absorbers with balanced electromagnetic attenuation, broad effective absorption bandwidth, and radar-scattering suppression capability is important for electromagnetic protection and stealth-related applications. Herein, CoS/C composite nanofibers were fabricated through electrospinning, surface-confined Co-MOF growth, carbonization, and subsequent sulfidation. The obtained one-dimensional composites consist of a PAN-derived conductive carbon framework decorated with CoS nanoparticles, producing CoS/C heterointerfaces and N/O/S-associated defect sites. By regulating the cobalt precursor content, the dielectric response and impedance matching of the composites were effectively tuned. The optimized CSN-6 sample achieves a minimum reflection loss of −61.33 dB at a thickness of 2.27 mm and an effective absorption bandwidth of 6.32 GHz at 2.31 mm, indicating a favorable balance between dielectric attenuation and impedance matching. Electromagnetic-parameter analysis suggests that the enhanced absorption mainly originates from conduction loss in the interconnected carbon-fiber network, CoS/C interfacial polarization, heteroatom/defect-induced dipolar relaxation, and possible multiple reflection/scattering within the fibrous architecture. CST simulations based on the measured electromagnetic parameters further show that the CSN-6-based absorber achieves a maximum simulated radar cross-section reduction of 17.53 dB relative to a perfect electric conductor at 14.56 GHz. Moreover, a simulation-guided gradient periodic unit cell was proposed as a proof-of-concept structural design, generating multiple absorption responses at 2.57, 7.56, and 13.47 GHz. This work provides an interface-regulation and structure-simulation strategy for developing dielectric-loss-dominated CoS/C fibrous microwave absorbers. Download: Download high-res image (390KB) Download: Download full-size image