Synergistic EMI shielding and impact resistance in nano-engineered aramid/carbon-PEEK composites via gradient architecture design

To address the inherent trade-off between electromagnetic interference (EMI) shielding and impact resistance, this study proposes a hierarchical dual-scale decoupling strategy. (1) Macro-scale spatial decoupling: Asymmetric distribution of aramid fibers (AFs) for the impact-resistant layer and carbon fibers for the EMI shielding layer in polyetheretherketone (PEEK) matrix, (2) Micro-scale EMI decoupling: Dual-layer CF architecture comprising MXene/PEI-CB interfacial engineered absorption layer (top) and MXene modified high-conductivity reflection substrate (bottom). Specifically, the strategy synergizes with AF surface modification via PI/CNT-COOH/ANF sizing and the construction of the MXene/PEI-CB and MXene conductive network on the CF surface. This design effectively separates the low-conductivity impact-resistant layer (AF) from the high-conductivity shielding layer (CF) in space, thereby eliminating the concentration conflict associated with interface modification. As a result, compared to the CM/PEEK composite, the asymmetric gradient design (ACM/PEEK) leads to a 26.9 % increase in the absorption coefficient (A), with the overall shielding effectiveness reaching 38.04 dB. Simultaneously, the nano-engineered interface, in conjunction with the intrinsic toughness of AF, effectively dissipates impact stress. Under an 8 J impact load, the peak load increases by 102.25 %, and the damage area is significantly reduced. This study successfully overcomes the traditional trade-off between mechanical robustness and EMI shielding performance. It offers a novel paradigm for the development of lightweight, structure-function integrated electromagnetic protection materials suitable for extreme service environment.