Preparation and thermoelectric properties of two types of nanostructured tellurium with multi-walled carbon nanotubes

Two types of MWCNT/Te nanostructure composites with two different types of Te particles (powder and nanorods) and various MWCNT contents were synthesized and their thermoelectric properties were analyzed. Te powder was prepared by ball-milling Te beads and Te nanorods were synthesized by PVP-assisted solution-phase mixing. The highest power factor was achieved with 2 wt% of MWCNTs in both types of MWCNT/Te composites, attributed to the extremely high electrical conductivity of the MWCNTs. Above 2 wt%, the low Seebeck coefficient of the MWCNTs caused a decrease in the power factor. Additionally, the introduction of the MWCNTs into the Te matrix reduced the thermal conductivity of the composite by generating numerous boundaries. The maximum thermoelectric figure of merit (ZT) (0.0037 at room temperature) is achieved with 2 wt% of MWCNTs in the MWCNT/Te nanorod composites; this value is larger than the ZT values of pure Te and the MWCNT/Te powder composite.