First-Principles Analysis of Lattice Thermal Conductivity in Monolayer Mn2C

The thermal transport properties of a new MXene material, Mn2C, have been investigated by solving the phonon Boltzmann transport equation based on the density functional theory. Monolayer Mn2C shows a relatively low intrinsic lattice thermal conductivity, which is about one-third that of Ti2C at room temperature. This is mainly due to the larger average atomic mass and stronger anharmonicity of Mn2C, which result from the larger difference in electronegativity between Mn and C atoms. Moreover, the greater participation of optical branches in phonon scattering also contributes to the lower lattice thermal conductivity of monolayer Mn2C. This study offers physical insights into the fundamental thermal transport properties of late-transition-metal-based (groups after VIB) MXene materials relevant for energy conversion and storage applications.