Sandwich structure electromagnetic interference shielding composites based on Fe3O4 nanoparticles/PANI/laser-induced graphene with near-zero electromagnetic waves transmission

High-performance electromagnetic interference (EMI) shielding materials with flexible and lightweight characteristics are still a hot research direction, which will be highly promising in many application fields. In this work, laser-induced graphene (LIG) as the top and bottom layer, and binary composites of co-precipitated Fe3O4 NPs and in-situ chemical polymerized PANI (FePA) functioned as the intermediate layer is assembled to prepare a sandwich structure shielding material (FePA/LIG composite). 3D porous LIG with excellent conductivity is conducive to promote reflection and multiple reflections of incident electromagnetic waves (EMWs), while the transmitted EMWs will be further absorbed and attenuated via FePA composite due to its high impedance matching and microwave absorption (MA) properties. Near-zero EMWs transmission can be achieved and the average EMI shielding effectiveness (SE) of FePA/LIG composite (with thickness less than 2 mm) over the entire X-band and Ku-band is 50 dB and 63 dB, respectively. The admirable EMI shielding performance and flexibility of FePA/LIG composite endows enormous potential in portable electronic devices.