Ultralow Thermal Conductivity and Enhanced Thermoelectric Performance of Cu2se Realized by Mxene (Ti3c2tx) Doping

Abstract

Due to the significant mismatch in phonon density of states between carbon (C) and Cu2Se, the thermal conductivity of Cu2Se can be notably enhanced by incorporating low-dimensional carbon-based materials. This study propose an innovative approach where two-dimensional MXene material Ti3C2Tx is introduced into Cu2Se, creating numerous Cu2Se/MXene hetero-geneous interfaces within the matrix. These interfaces induce high-density dislocations, which enhance multi-scale phonon scattering efficiency. Consequently, they significantly reduce latticethermal conductivity across the entire temperature range tested. Additionally, the heterogeneousinterfaces facilitate energy filtration, selectively filtering out low-energy carriers and therebyoptimizing the high intrinsic carrier concentration of Cu2Se to a certain extent. Finally, the total thermal conductivity of the Cu2Se/0.4 wt% Ti3C2Tx sample at 795 K is markedly lower at 0.27 Wm−1K−1 compared to the average level of Cu2Se materials. As a result, the ZTmax reaches 2.11, reflecting a 109% enhancement compared to pristine Cu2Se.

Keywords: Cu2SeHeterogeneous interfacesSecondary phasesZT