Multifunctional metallized basalt/PA6 composites: EMI shielding, joule heating, and tunable rigidity

The emerging demands of the low-altitude economy necessitate structural materials that simultaneously achieve lightweight design, mechanical robustness, electromagnetic interference (EMI) shielding, and thermal management—capabilities rarely coexisting in conventional composites. Although polyamide 6 (PA6)/basalt fiber (BF) composites offer sustainability and high specific strength, their practical application is severely limited by weak fiber–matrix interfacial adhesion and intrinsic electrical insulation, resulting in poor EMI shielding and thermal transport capability. Herein, a noble-metal-free, self-catalytic electroless copper plating strategy is reported to functionalize basalt fibers and fabricate laminated PA6/Cu@BF composites with synergistic structural–functional integration. A uniform and compact three-dimensional conductive copper layer was constructed in situ on the BF surface without palladium activation, providing continuous electrical pathways and micro/nanoscale surface features that significantly enhanced interfacial wetting and adhesion with the PA6 matrix. As a result, the composite exhibited an ultrahigh average EMI shielding effectiveness of 85.6 dB in the X-band at a thickness of only 0.6 mm. Benefiting from the reinforced interface, the impact strength increased by 253.4% compared with the unmodified composite. In addition, the interconnected copper network enables enhanced in-plane thermal transport (80.2% improvement) and rapid Joule heating, reaching 98.5 °C within 30 s under a low voltage of 3 V, demonstrating strong potential for fast de-icing and localized thermal regulation. This work provides a sustainable, low-cost, and scalable strategy for simultaneously enhancing interfacial integrity and multifunctional performance of PA6/BF composites, offering a promising structural–functional integrated material platform for low-altitude aerial systems.