Sequentially Bridged Ti₃C₂T_x MXene Sheets for High Performance Applications

The outstanding electrical conductivity and high specific capacitance of 2D Ti₃C₂T_x MXene have made them promising materials for a wide range of applications including wearable electronics, energy storage, sensors, and electromagnetic interference shielding. However, the fabrication of MXene architectures, both pure and composite, often results in a trade-off in properties. Here, it is reported that sequential bridging of MXene sheets significantly enhances the mechanical properties of its free-standing films, with improvements in strength and toughness of up to ≈339 MPa and ≈12.0 MJ m⁻³, respectively, while simultaneously retaining both high conductivity (≈4850 S cm⁻¹) and volumetric capacitance (≈1220 F cm⁻³). This sequential bridging strategy permits surface modification of MXene sheets while still yielding stable colloidal dispersions so that the subsequent MXene films comprise of aligned, evenly-spaced, and interconnected sheets, which are critical for the development of robust energy storage devices and other high performance applications.