Ultrathin and flexible polyimide/Ti₃C₂T_X MXene composite films for electromagnetic interference shielding with harsh environment tolerance

Two-dimensional MXene materials show great potential for electromagnetic interference (EMI) shielding application because of their superior electrical conductivity. However, the susceptibility to oxidation and the mechanical brittleness of MXenes greatly limit their extensive application. Herein, an ultrathin flexible polyimide (PI)/Ti3C2TX composite film with a nacre-like lamellar structure is successfully prepared using a simple vacuum filtration and thermal imidization process. Owing to the addition of PI, the composite film exhibits excellent mechanical properties with a tensile strength of 114.9 MPa and a fracture strain of 3.0%. Moreover, the nacre-like lamellar structure is conducive to multiple internal reflections, giving rise to the absorption of electromagnetic waves. The PI/Ti3C2TX composite film exhibits an outstanding EMI shielding effectiveness of 37 dB in the X-band range with an ultrathin thickness of only 15 mu m. Furthermore, PI serves as an antioxidation coating, and its EMI shielding performance is maintained even when the composite film is exposed to various harsh environments. Therefore, the resulting composite film exhibits excellent EMI shielding stability and durability, which enables the potential application of high-performance EMI shielding materials against harsh environments.