The thermoelectric properties of BaxIn0.2−x Co4Sb11.5Te0.5 synthesized at different pressure

A series of skutterudite compounds BaxIn0.2−x Co4Sb11.5Te0.5 (x = 0.05, 0.1, 0.15) have been prepared successfully by high pressure and high temperature (HPHT) method and then characterized with X-ray diffraction and electron microprobe analysis. The thermoelectric properties including Seebeck coefficient α, electrical resistivity ρ and thermal conductivity κ were measured at room temperature. As expected, with the synthetic pressure increased, the Seebeck coefficient and thermal conductivity of BaxIn0.2−xCo4Sb11.5Te0.5 both improved significantly. Moreover, the lattice thermal conductivity decreased distinctly with pressure increasing, which was mainly due to the abundant grain boundaries, which could enhance the phonon scattering effectively at grain boundaries. The test results suggest that the HPHT technique is a superior method to optimize thermoelectric properties of thermoelectric materials.