文摘
In order to enhance the thermoelectric (TE) properties of CoSb3, we tried to reduce the lattice thermal conductivity (κlat) by filling Tl into the voids and substitution of Rh for Co. We prepared polycrystalline samples of Tlx(Co1−yRhy)4Sb12 (x = 0, 0.05, 0.10, 0.15, 0.20 and y = 0.1, 0.2) and examined their TE properties from room temperature to 750 K. All the samples indicated negative values of the Seebeck coefficient (S). Both the electrical resistivity and the absolute values of the S decreased with increasing the Tl-filling ratio. The Tl-filling and Rh substitution reduced the κlat, due to the rattling and the alloy scattering effects. The minimum value of the κlat was 1.54 W m−1 K−1 at 550 K obtained for Tl0.20(Co0.8Rh0.2)4Sb12. Tl0.20(Co0.8Rh0.2)4Sb12 exhibited the best TE performance; the maximum value for the dimensionless figure of merit ZT was 0.58 at around 600 K.
