Ultrastrong and conductive MXene/cellulose nanofiber films enhanced by hierarchical nano-architecture and interfacial interaction for flexible electromagnetic interference shielding

Abstract

With the development of wearable and portable electronic devices, there is growing demand for ultrathin high-performance electromagnetic interference (EMI) materials with desirable mechanical properties. In this study, 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidized cellulose nanofibers (TOCNFs) were used to fabricate ultrathin and flexible Ti₃C₂T_x/TOCNF composite films with a nacre-like layered structure via a simple vacuum-assisted assembly. These composite films present excellent mechanical strength (up to 212 MPa) and Young's modulus (up to 7 GPa) due to their strong intermolecular interaction and hierarchically aligned structure, which is superior to the state-of-the-art MXene-based functional materials. Furthermore, the Ti₃C₂T_x/TOCNF composite films exhibit high electrical conductivity (up to 2837 S m⁻¹) and an outstanding EMI shielding effectiveness (SE) of 39.6 dB at a very low thickness of 38 μm. The possible synergistic mechanisms enhancing the mechanical properties and EMI shielding performance are discussed. The design and fabrication of Ti₃C₂T_x/TOCNF composite films provide a versatile strategy for ultrathin high-performance EMI shielding materials with desirable mechanical properties, which have great potential for various applications, especially in flexible, wearable and portable electronics.