Thermoelectric properties of Te-doped CoSb3 by spark plasma sintering

Te-doped CoSb3 bulk polycrystalline materials Co4Sb12−xTex have been prepared by melting, annealing, and spark plasma sintering and have been characterized by x-ray diffraction. From the lattice constants of the Te-doped samples, a Te substituting fraction limit for Sb is estimated to be x=0.55. The Hall effect, Seebeck coefficient, electrical-conductivity, and thermal-conductivity measurements were performed between room temperature and 900K. The Te-doped materials Co4Sb12−xTex show an n-type conduction. As the Te fraction increases, the electron concentration and the electrical conductivity of the samples increase, while the Hall mobility, the absolute Seebeck coefficient, and the thermal conductivity decrease. A maximum dimensionless figure of merit of 0.72 is obtained at 850K for Co4Sb11.5Te0.5.