Achieving flexible and durable electromagnetic interference shielding fabric through lightweight and mechanically strong aramid fiber wrapped in highly conductive multilayer metal

Highlights: • Ni/Cu/Ni coated aramid fiber exhibits extremely low resistivity. • The 'sandwich' metal structure of Ni/Cu/Ni has excellent environmental stability. • AF/Ni/Cu/Ni multi-interface enhanced the multiple reflection and absorption effects. Lightweight and flexible electromagnetic interference (EMI) shielding materials with excellent electrical conductivity, mechanical performances and environmental stability are urgently demanded to address EM radiation pollution in the fields of aerospace, robotics, fabric sensors and flexible antennas. Herein, an outstanding candidate material for EMI shielding of an aramid fiber (AF) core wrapped in a composite metal shell composed of amorphous Ni, crystalline Cu and Ni has been successfully manufactured through delicate architecture design and convenient preparation approach. The Ni/Cu/Ni coated AF not only retained the high load capacity and high thermal stability of the substrate, but also achieved a low resistivity of the same order of magnitude as that of metallic Cu. Even after being corroded via HCl, NaOH, NaCl solution for 48 h and treated at a high temperature of 150°C for 168 h, it still maintained good mechanical properties and electrical conductivity, demonstrating satisfactory environmental stability. The morphology and resistance of Ni/Cu/Ni coated AF after thermal shock and 500 bending cycles have no significant changes, which indicated that the bonding of Ni/Cu/Ni and AF was firm. Furthermore, the existence of AF/Ni, Ni/Cu and Cu/Ni multiple interfaces enhanced the multiple reflection and absorption of EM radiation, and final fabric showcased stronger absorption and weaker reflection of EM radiation.