Thermal conductivity measurement of individual MXene (Ti₃C₂T_x) flakes

MXenes, a novel class of two-dimensional (2D) transition metal carbides and nitrides, have garnered considerable attention due to their exceptional properties, e.g., high electrical conductivity, electromagnetic shielding capabilities, and potential applications in energy storage and thermal management. However, a comprehensive understanding of their thermal transport properties, particularly at the individual flake unit, is essential for optimizing their performance in device applications. In this study, we systematically investigate the in-plane and cross-plane thermal conductivity of individual MXene (Ti₃C₂T_x) flakes, which were measured using the suspended micro-bridge method and Time-Domain Thermoreflectance (TDTR), respectively. The measurements were performed over a temperature range of 80–320 K with MXene flakes, of which the thicknesses ranged from 5 to 32 nm, corresponding to approximately 4–21 layers. Our results reveal that flake thickness and oxidation state significantly influence the thermal transport properties. A polypropylene carbonate (PPC) and water bridge-assisted transfer method was employed to ensure clean and accurate placement of the ultra-thin flakes. These findings contribute to a fundamental understanding of the thermal properties of MXenes and underscore their potential in thermal management applications.