Flexible, mechanically robust and self-extinguishing MXene/wood composite for efficient electromagnetic interference shielding

Due to the increasingly severe electromagnetic pollution, the green, lightweight, and high-performance electromagnetic interference (EMI) shielding materials need to be urgently developed. However, there are still challenges in constructing biomass-based high-performance electromagnetic shielding materials through uncomplicated methods. Herein, a flexible MXene/wood composite (F-MWC) with sandwich structure was constructed for EMI shielding application based on MXene and delignified wood via impregnation and densification process. The resultant F-MWC shows the mechanical properties with a tensile strength of 68.1 MPa, and excellent flexibility compared with natural wood due to the thinner thickness and highly aligned cellulose nanofibers. It also shows remarkable fire-retardant properties with a self-extinguishing effect attributed to the synergistic effect of MXene's flame retardancy and densification treatment. Moreover, F-MWC possessed a high electrical conductivity of 1858 S m-1 and excellent EMI-shielding effectiveness of 32.7 dB at a thickness of only 0.38 mm. In addition, the multilayered MXene/wood composite assembled by cross-combining F-MWC along the fiber direction with better EMI-shielding effectiveness and strength makes it more scalable in applications. This technique provides an alternate strategy for producing wood-based EMI shielding materials for electronic devices, packaging, and modern buildings.