Lightweight graphene foam composites with enhanced electrical conductivity and microwave absorption for electromagnetic interference shielding

Next-generation flexible electronics call for high-performance electromagnetic interference (EMI) shielding materials with lightweight and multifunctionality. Here, the chemical vapor deposition (CVD) graphene foam (GF) composites, containing flexible polymer matrix and magnetic Fe₃O₄ nanoparticles, are reported. The systematic manipulation of GF growth condition and the content of Fe₃O₄ reveals the effect of graphene thickness and integration of Fe₃O₄ on improving the electromagnetic shielding performance of composites. Owing to abundant internal interfaces, high conductivity from the three-dimensional interconnected graphene, and magnetic loss from Fe₃O₄, the ternary composites exhibit substantial improvement in microwave absorption, resulting in a superior EMI shielding effectiveness (SE) and absolute EMI SE up to 71 dB and 3641 dB·cm²/g, respectively, at a low density of 0.65 g/cm³ and minimal thickness of 0.3 mm. Moreover, the flexible composites display great EMI shielding stability after repeatedly bending, validating the composites as promising materials for practical applications in aerospace and flexible electronics.