Synthesis and Thermoelectric Properties of (Sr,Yb)yCo4Sb12 Double Filled Skutterudites

Abstract

(Sr,Yb)_yCo₄Sb₁₂ double filled skutterudites are synthesized by a melting method and sintered by Spark Plasma Sintering (SPS) technique. Small amount of Yb₂O₃ and YbSb₂ as impurity phases are found with high ytterbium content in the X-ray diffraction patterns of sintered materials. The thermal conductivity, electrical conductivity and Seebeck coefficient are measured from room temperature to 850 K. The influence of different filling fractions of ytterbium on the thermoelectric properties of (Sr,Yb)_yCo₄Sb₁₂ is studied. The lattice thermal conductivity of double filled skutterudites is reduced dramatically as compared to that of Sr single-filled skutterudites with similar filling fractions. An enhancement in power factor and dimensionless thermoelectric figure of merit (ZT) is observed in the double filled skutterudites