Mechanical Properties and Reinforcement Effect of Single MXene Flakes and MXene Composites

MXenes as new two-dimensional materials show promising applications in various fields due to their remarkable electrical and mechanical properties. However, transferring those outstanding MXene properties into films and bulk composites is challenging as they exhibit low mechanical properties and electrical conductivity, far lower than predicted. The primary reasons for this are voids, misalignment, and weak interfaces in the MXene composites. In this chapter, we first discuss the intrinsic mechanical properties of MXenes, which were derived from single-flake nanoindentation measurements. Then, we summarize the mechanical properties, such as tensile strength and the toughness, of MXene composites, including one-dimensional fiber, two-dimensional film, and three-dimensional bulk composites. The other functional properties, focusing on electrical conductivity and electromagnetic interference shielding, are also discussed. Effective sequential bridging assembly strategies for fabricating high-performance MXene composites are discussed as well. Finally, we present a future outlook describing several effective venues for constructing high-performance MXene composites with properties approaching those of individual MXene flakes.