AgSbTe2 nanoinclusion in Yb0.2Co4Sb12 for high performance thermoelectrics

• AgSbTe2 inclusions, about 50 nm in size, are evenly distributed at the grain boundary.
• The electrical conductivity and Seebeck coefficient increase with the addition of AgSbTe2.
• The lattice thermal conductivity decreases with the addition of AgSbTe2.
• A maximum ZT of 1.27 was obtained for the Yb0.2Co4Sb12/4wt%AgSbTe2 composite sample.

Yb0.2Co4Sb12 based composites with AgSbTe2 nanoinclusion have been successfully prepared by a combined process of vacuum melting, pulverization and hot press sintering. XRD, FESEM, TEM and EDS were performed to characterize the microstructure and composition of the nanocomposites. It shows AgSbTe2 inclusions are about 50 nm in size and they distribute in the grain boundaries of Yb0.2Co4Sb12 filled skutterudite matrix. When the content of AgSbTe2 is less than 8wt%, Seebeck coefficient and electrical conductivity of the composites increase with increasing content of AgSbTe2, while the lattice thermal conductivity reduces with the increase of AgSbTe2 nanoinclusions. As a result, thermoelectric performance is improved with addition of AgSbTe2 nanoinclusion and a maximum ZT of 1.27 has been obtained for the sample of Yb0.2Co4Sb12/4wt%AgSbTe2 at about 300 °C.