Influence of Carbon Nanotubes on the Thermoelectric and Mechanical Properties of Cu2.1Mn0.9SnSe4 Alloy

Abstract

Quaternary chalcogenides are viewed as a class of potential thermoelectric materials due to their good thermoelectric performance in the medium temperature region. In this work, carbon nanotubes (CNTs) with varying weight percentages are composited into the quaternary chalcogenide Cu_2.1Mn_0.9SnSe₄ (CMTS) using a technique that combines ball-milling and hot-pressing, and the effect of CNTs on the thermoelectric performance of CMTS is investigated. The compositing of CNTs results in an increase in the intrinsic defects of CMTS, thereby enhancing the electrical conductivities of the composited samples. Besides, the addition of CNTs introduces various phonon scattering mechanisms, effectively restraining the lattice thermal conductivities of the composited samples, particularly in the low to medium temperature range. Ultimately, owing to the concurrent optimization of the power factor and thermal conductivity, the x = 0.25 sample achieves a zT value of 0.37 at 673 K. The compositing of highly conductive secondary phase is recognized as a viable approach for the simultaneous enhancement of the thermoelectric properties of materials.