Simultaneously Achieving High‐Temperature Resistance, <scp>EMI</scp> Shielding, and Mechanical Performance in <scp>CF</scp> / <scp>PEEK</scp> Composites via Interface Engineering

ABSTRACT The advancement of structural‐functional thermoplastic composites with integrated electromagnetic shielding (EMI) and mechanical properties represents a key trend in aerospace. A key challenge is ensuring EMI performance and robust interfacial properties under the high processing temperatures of thermoplastic matrices. In this study, nickel plating on carbon fibers (CFs) was used to enhance the electrical conductivity of the composites. Sulfonated polyether ether ketone (SPEEK) was then employed on the nickel‐plated CFs to improve the interfacial performance between fibers and the PEEK matrix. The results showed that introducing 2% SPEEK increased the ILSS and tensile strength of CF‐Ni/PEEK composites by 25.1% and 25.6%, respectively. Additionally, CF‐Ni‐SPEEK/PEEK composites showed an 18.8% improvement in EMI shielding effectiveness, achieving an ILSS (Interlaminar Shear Strength) of 46.4 MPa and EMI SE of 36.1 dB. These results provide valuable insights for designing advanced composites with combined structural and functional properties for aerospace applications.