Enhanced thermoelectric performance of CuAlS2 by adding multi-walled carbon nanotubes

Abstract

In this paper, we report the first-ever study on a relatively uniform dispersion of multi-walled carbon nanotubes (MWCNTs) in CuAlS2 nanoparticles, synthesized by high-energy ball-milling, and study the thermoelectric properties of the bulk materials. A vortex mixer and bath sonicator are used to achieve well dispersion of nanotubes in the matrix, and then the powder is hot-pressed. Carbon nanotubes dispersed in the matrix improve electrical conductivity and Seebeck coefficient. The addition of MWCNT causes an increase in the grain boundary and facilitates phonon scattering, resulting in a reduction in the lattice thermal conductivity and finally total thermal conductivity. The optimum amount of carbon nanotubes is effective for reducing thermal conductivity and increasing electrical conductivity, thereby elevating the figure-of-merit of the nanocomposites. Finally, the figure-of-merit is highly influenced by total thermal conductivity, and the maximum figure-of-merit was obtained for CuAlS2/0.5 wt% MWCNT composite, which indicated about 20% improvement.