Lightweight and mechanically strong polyimide/carbon fibre composites with 3D asymmetric conductive network for integrated low-reflection EMI shielding and infrared-stealth capacity

Lightweight and mechanically strong multifunctional polymer composites with low-reflection electromagnetic interference (EMI) shielding and infrared stealth capacity are urgently needed to protect emerging electronic technologies in aerospace and military equipment. In this work, the polyimide nanocomposites composed of graphene nanosheets/Fe 3 O 4 modified three-dimensional (3D) asymmetric conductive network were developed via in-situ growth and co-carbonization strategy using hierarchical modular design. Owing to the construction of 3D asymmetric conductive network, along with spatial coupling between the magnetic/dielectric synergistic loss, the resulting composites exhibit low mass density of 1.09 g/cm 3 , excellent EMI shielding effectiveness of 54.7 dB, and high absorption coefficient of 0.72, as well as outstanding heat-resistant mechanical properties with an improved tensile strength of 31.1 MPa and reliable infrared stealth performance. Moreover, by virtue of the multiple reflection and absorption shielding mechanism triggered by the 3D asymmetric conduction network and the synergistic effect of thermal regulation, remarkable electromagnetic wave absorption and thermal infrared stealth dual capabilities have been attained. The lightweight, mechanically strong, and absorption-dominated carbon-based polyimide electromagnetic shielding composite holds great promise for emerging applications in EMI shielding and infrared stealth in aerospace and military equipment.