Integrating Thermal, EMI Shielding, and Mechanical Properties in Carbon Fiber/Epoxy Resin Composites via Interface‐Layup Synergistic Design

Abstract Next‐generation aerospace systems require carbon fiber/epoxy resin (CF/EP) composites that simultaneously deliver high thermal conductivity, electromagnetic interference (EMI) shielding, and mechanical properties, yet conventional designs face inherent property trade‐offs. To address this challenge, an interface‐layup synergistic engineering strategy is proposed. A 3D CF felt architecture is synthesized through in situ hydrothermal growth of MnO 2 microporous transition layers, augmented by Fe nanoparticle deposition via chemical reduction. This engineered framework is subsequently integrated with CF cloths, forming a multiscale CF/EP composite through vacuum‐assisted resin infusion. The MnO 2 transition interface functions as a phonon transmission mediator, preserving modulus continuity across interfaces while reducing thermal boundary resistance through lattice vibration coupling. Concurrently, Fe nanoparticles create electron transport networks, thus suppressing phonon scattering. This coordinated mechanism achieves exceptional directional thermal conductivities ( к ⊥ = 0.82 W m −1 K −1 ; к // = 4.41 W m −1 K −1 ) coupled with superior EMI shielding effectiveness (SE = 69.85 dB). Through strategic layering optimization, the developed composite exhibits simultaneous mechanical enhancement with an interlaminar shear strength (ILSS) of 70.18 MPa and flexural strength of 1074.95 MPa, corresponding to 41.89% and 27.23% improvements over conventional CF/EP composites. This strategy effectively realizes the unprecedented synergistic integration of thermal management, electromagnetic interference shielding function, and structural performance in multifunctional composites.