Binary Strengthening and Toughening of MXene/Cellulose Nanofiber Composite Paper with Nacre-Inspired Structure and Superior Electromagnetic Interference Shielding Properties

With the growing popularity of electrical communication equipment, high-performance electromagnetic interference (EMI) shielding materials are widely used to deal with radiation pollution. However, the large thickness and poor mechanical properties of many EMI shielding materials usually limit their applications. In this study, ultrathin and highly flexible Ti₃C₂T _x (d-Ti₃C₂T _x, MXene)/cellulose nanofiber (CNF) composite paper with a nacre-like lamellar structure is fabricated via a vacuum-filtration-induced self-assembly process. By the interaction between one-dimensional (1D) CNFs and two-dimensional (2D) d-Ti₃C₂T _x MXene, the binary strengthening and toughening of the nacre-like d-Ti₃C₂T _x/CNF composite paper has been successfully achieved, leading to high tensile strength (up to 135.4 MPa) and fracture strain (up to 16.7%), as well as excellent folding endurance (up to 14 260 times). Moreover, the d-Ti₃C₂T _x/CNF composite paper exhibits high electrical conductivity (up to 739.4 S m^-1) and excellent specific EMI shielding efficiency (up to 2647 dB cm² g^-1) at an ultrathin thickness (minimum thickness 47 μm). The nacre-inspired strategy in this study offers a promising approach for the design and preparation of the strong integrated and flexible MXene/CNF composite paper, which may be applied in various fields such as flexible wearable devices, weapon equipment, and robot joints.