Effect of Nano-ZrW2O8 on the Thermoelectric Properties of Bi85Sb15/ZrW2O8 Composites

Abstract

In this study, Bi85Sb15/x wt.% ZrW2O8 (x = 0, 0.1, 0.5, 1) thermoelectric nanocomposites were prepared successfully by ball milling and spark plasma sintering. The effect of ZrW2O8 nanoparticles on the thermoelectric properties of the Bi85Sb15/ZrW2O8 composite was investigated. Thermal conductivity, Seebeck coefficient, and electrical conductivity were measured between 77 K and 300 K. x-Ray diffraction and scanning electron microscopy were adopted for microstructure characterization of the composites. The electrical transport properties are mainly discussed with regard to the microstructures. The results show that nanoinclusions did not grow during sintering. It is found that the thermal conductivity decreases with the addition of a small amount of ZrW2O8 nanoparticles, which serve as additional phonon-scattering centers. The obtained thermal conductivity is 0.5 W/m K for the Bi85Sb15/1 wt.% ZrW2O8 composite at 80 K, which is just half of the value for the Bi85Sb15 matrix. However, the electrical transport properties are degraded with increasing content of ZrW2O8. The calculated ZT is also degraded due to the poor electrical properties.