Effect of Rh Substitution for Co on the Thermoelectric Properties of CoSb₃

Abstract

CoSb₃ is known as a skutterudite compound that could exhibit high thermoelectric figure of merit. However, the thermal conductivity of CoSb₃ is relatively high. In order to enhance the thermoelectric performance of this compound, we tried to reduce the thermal conductivity of CoSb₃ by substitution of Rh for Co. The polycrystalline samples of (Co_1−xRh_x)Sb₃ (x=0, 0.1, 0.2, and 0.3) were prepared and the thermoelectric properties such as the Seebeck coefficient, electrical resistivity, and thermal conductivity were measured in the temperature range from room temperature to 750 K. The Rh substitution for Co reduced the lattice thermal conductivity, due to the alloying scattering effect. The minimum value of the lattice thermal conductivity was 4 Wm⁻¹K⁻¹ at 750 K obtained for (Co_0.7Rh_0.3)Sb₃.