Sulfur vacancy rich carbon/FeS/Fe3O4 composite with synergistic dielectric-magnetic loss for enhanced microwave absorption

Ion-exchange resin serve as dual sulfur/carbon sources for C/FeS/Fe 3 O 4 . • Sulfur vacancies and heterointerfaces synergistically boost polarization loss. • Synergistic dielectric-magnetic loss mechanisms yield RL min of −69.2 dB. • Flexible C/FeS/Fe 3 O 4 -silicone rubber plate shows excellent application potential. Transition metal sulfide (TMS)-based composites have shown great promise for microwave absorption, yet achieving high attenuation and broadband absorption simultaneously remains a critical challenge. Herein, ion-exchange resin is innovatively employed as a dual source of sulfur and carbon to prepare a magnetic C/FeS/Fe 3 O 4 composite rich in sulfur vacancies, which achieves synergistic dielectric-magnetic dissipation for efficient electromagnetic wave (EMW) absorption. The preparation involves a simple process of ion exchange, physical adsorption and carbonization, during which FeS and Fe 3 O 4 are generated in situ on the resin-derived porous carbon skeleton. The abundant sulfur vacancies, heterogeneous interfaces, and three-dimensional conductive network synergistically enhance dipole polarization, interfacial polarization and conductive loss. Moreover, the ferromagnetic Fe 3 O 4 component contributes to magnetic loss. These synergistic dielectric-magnetic loss mechanisms endow C/FeS/Fe 3 O 4 composite with both excellent attenuation capacity and favorable impedance matching. Consequently, the composite delivers outstanding EMW absorption performance, exhibiting a minimum reflection loss (RL min ) of −69.2 dB at a thickness of 1.65 mm and an effective absorption bandwidth (EAB) of 5.1 GHz at 1.50 mm. Radar cross-section (RCS) simulations demonstrate that C/FeS/Fe 3 O 4 can significantly suppress radar-wave scattering, achieving a maximum RCS reduction of 28.0 dB m 2 . Furthermore, the composite shows excellent application potential when incorporated into a flexible, heat-dissipating, microwave-absorbing C/FeS/Fe 3 O 4 -silicone rubber plate. This work provides valuable insights into the rational design and fabrication of high-performance TMS-based EMW absorbers. Download: Download high-res image (445KB) Download: Download full-size image