Coincident modulation of lattice and electron thermal transport performance in MXenes via surface functionalization

Efficiently modulating the thermal transport performance of materials including MXenes is highly desired as heat transfer is critical in a wide range of applications. However, the design principles for MXenes to achieve optimized thermal conductivity are not yet understood. Herein we highlight that the thermal conductivity modulation can be achieved by altering the surface fuctionalization, which also exhibits unexpected coincident effects on both the lattice and electron contribution to thermal transport. Our results indicate that the functionalization of O significantly decreases both the lattice and electron thermal conductivities of Ti2C MXenes because O will induce not only a shorter phonon relaxation time but also a metal-semiconductor transition, showing great potential for applications including thermoelectrics. In contrast to O, after being functionalized by F or OH both the lattice and electron thermal conductivities are increased, which will improve heat dissipation in electronics and batteries. Our findings will provide a fundamental guideline to the design of MXene-based devices with optimal thermal transport performance.