Extraordinary Electromechanical Actuation of Ti₂C MXene

Abstract

Two-dimensional transition-metal carbides and nitrides, often known as MXenes, have fantastic properties benefiting from their unique structures, enabling them to be used in many applications. In this work, we show that Ti2C MXene possesses extraordinary electromechanical actuation performance using first-principles calculations. Upon charge injection, the maximum uniaxial and biaxial isometric actuation stresses are 31.1 (along the armchair direction) and 75.6 GPa, respectively, and the maximum isobaric actuation strain is 27.4%. More importantly, the electromechanical actuation of Ti2C MXene is in-plane isotropic because of the 3-fold rotational symmetry, and the in-plane area can be stimulated to increase by 62.2%, which is greater than other well-known two-dimensional materials. The maximum realistic gravimetric work density of Ti2C MXene is also extraordinary (1271.6 J/g). Finally, the mechanism for the extraordinary electromechanical actuation performance of Ti2C MXene was elucidated by the analyses at atomic and electronic scales. Additionally, mechanical tests show that the structural integrity of Ti2C MXene can be well maintained under a certain amount of electromechanical loads. Our findings indicate that Ti2C MXene can be used for high-performance nanoelectromechanical actuators.