Effect of Surface Termination on the Lattice Thermal Conductivity of Monolayer Ti3C2Tz MXenes

TL;DR

This study investigates how different surface terminations affect the lattice thermal conductivity of monolayer Ti3C2Tz MXenes, revealing significant variations linked to surface chemistry that impact their thermal management in devices.

Contribution

It provides the first detailed theoretical analysis of how surface termination influences thermal transport in Ti3C2Tz MXenes using DFT and phonon Boltzmann transport calculations.

Findings

Fluorine termination increases thermal conductivity by about ten times compared to oxygen termination.

Enhanced specific heat and phonon group velocity contribute to higher thermal conductivity in fluorine-terminated MXenes.

Surface chemistry critically affects thermal properties, impacting MXene applications in electronics and energy devices.

Abstract

Recently two-dimensional (2D) transition metal carbides and nitrides (MXenes) have gained significant attention in electronics and electrochemical energy conversion and storage devices where the heat production significantly affects the safety and performance of these devices. In this paper, we have studied the thermal transport in monolayer Ti3C2Tz, the first and most studied MXene, using density functional theory (DFT) and phonon Boltzmann transport equation and quantified the effect of surface termination (bare, fluorine and oxygen) on its lattice thermal conductivity. We found that thermal conductivity of fluorine-terminated Ti3C2Tz (108 W/m.K) is approximately one order of magnitude higher than its oxygen-terminated counterpart (10 W/m.K). Our calculations reveal that the increased thermal conductivity for the fluorine-terminated structure is due to its enhanced specific heat and group velocity and diminished scattering rate of phonons.