Integrated structural-functional MXene-GNs/ANF flexible composite film with enhanced thermal conductivity and electromagnetic interference shielding performance

The development of high-performance structural-functional composites capable of reconciling mechanical robustness with multifunctional integration remains a critical challenge. Inspired by the hierarchical structure of nacre layers, we have created flexible ternary composites featuring an interpenetrating three-dimensional (3D) network of MXene (Ti 3 C 2 T x ), graphene nanosheets (GNs), and aramid nanofibers (ANF). This multiscale strategy synergistically combines hydrogen bonding and a nacre-mimetic hierarchical structure with a 3D interpenetrating network, enabled by GNs for interfacial lubrication to overcome the strength-toughness trade-off while facilitating multifunctionality. The optimized MXene-GNs/ANF (60 wt% MXene-GNs, 50:50 ratio, 28 μm thickness) achieves exceptional mechanical properties: tensile strength of 175.10 ± 3.80 MPa, strain at break of 18.56% ± 0.78%, toughness of 15.88 ± 0.60 MJ m −3 . Simultaneously, it shows an electromagnetic interference shielding effectiveness (EMI SE) of 36.4 dB (8.2–12.4 GHz) and in-plane thermal conductivity (TC) of 11.58 W m −1 K −1 . Increasing the thickness to 65 μm further enhances EMI SE to 40.2 dB and TC to 23.21 W m −1 K −1 , outperforming most reported analogues. The composite also exhibits excellent thermal stability, with no significant weight loss below 558°C in the N 2 atmosphere, as well as multifunctional properties such as rapid Joule heating (∼160°C at 4 V), environmental resilience, and flame-retardant fire alert. By harmonizing interfacial interactions and hierarchical structuring, this work provides a scalable route to advanced flexible materials for next-generation wearable electronics and extreme-environment applications requiring integrated mechanical durability EMI shielding, and thermal management.