Constructing 3D carbon-metal hybrid conductive network in polymer for ultra-efficient electromagnetic interference shielding

In the present work, an effective and versatile strategy is adopted to fabricate ultra-efficient electromagnetic-interference (EMI) shielding composites by constructing perfect 3D carbon-metal hybrid conductive network in polyamide 6 (PA6) matrix. The surface of PA6 granules is first functionalized with expanded graphite (EG) sheets as conductive substrate and subsequently coated with very thin nickel (Ni) layer to form core-shell PA6/EG/Ni complex particles, then highly efficient PA6 shielding composites with well-connected 3D Ni-EG hybrid conductive network can be assembled by a conventional hot compression of the complex particles. The lamellar EG sheets not only serve as deposition template to induce a homogeneous and compact deposition of thin Ni plating, but also facilitate the formation of perfect 3D Ni-EG conductive network by restricting the diffusion between Ni and low-viscosity PA6 melt during hot compression. Benefit from this unique 3D carbon-metal hybrid network and a synergistic effect of the Ni-EG multilayer structure, the PA6/EG/Ni composite shows an ultra-efficient EMI shielding performance of 77.3 dB with extremely low filler content (0.9 vol%). This feasible approach of constructing 3D carbon-metal hybrid network in polymer matrix provides a new possibility for developing affordable high-performance EMI shielding composites for next-generation communication applications.