Hierarchical core-shell FeS2/Fe7S8@C microspheres embedded into interconnected graphene framework for high-efficiency microwave attenuation

With the imminent era dominated by high-tech electronic products, the development of high-efficiency electromagnetic wave absorption materials has become a critical task. Rational component regulation and structural design are considered to be effective methods to optimize the electromagnetic wave absorption performance of materials. Herein, we first prepared a [email protected] [email protected] precursor via solvothermal method; then, vulcanization was used to develop a FeS2/Fe7S8@[email protected] composite with a core-shell heterostructure, in which core-shell FeS2/Fe7S8@C microspheres were embedded on the wrinkled reduced graphene oxide layer. FeS2/Fe7S8@[email protected], as a multi-component composite, demonstrates superior impedance matching and can thus capture more electromagnetic waves, while the multiple losses facilitate the dissipation of incident electromagnetic waves. Concretely, FeS2/Fe7S8@[email protected] can display significant attenuation of incident electromagnetic waves through multi-interface polarization, dipole polarization, resonance loss and eddy current loss. Additionally, the three-dimensional hierarchical structure not only improves the conductive loss, but also promotes multiple reflections and scattering. The FeS2/Fe7S8@[email protected] composite exhibits a minimum reflection loss of −62.7 dB and an effective absorption broadband (6.1 GHz) with a filler loading of 20 wt% at 2.2 mm, and the effective absorption bandwidth reaches 7.6 GHz at a layer thickness of 2.5 mm. These results provide a valuable reference for the preparation of high-performance microwave absorbers through composition adjustment and controlled structural design.