Thermoelectric Properties of Iron-and Lanthanum-Doped CoSb3 Compounds by Pulse Discharge Sintering

Abstract

of fossil fuels. In this regard, thermoelectric power generation that can directly convert the thermal energy to electrical energy is one of the attractive methods. Skutterudite compounds of CoSb3 have been investigated as promising candidate materials for thermoelectric power generation. In this research, CoSb3 compounds were synthesized from raw metal powders by using a pulse discharge sintering process. To improve the thermoelectric properties, iron was doped as an element substituting for cobalt of the CoSb3 compound. The syntheses of FexCo1xSb3 were confirmed by x-ray diffraction analysis. The Seebeck coefficient, electric resistivity, and thermal conductivity were measured as the thermoelectric properties. Optimum content of iron was decided from the maximum thermoelectric figure of merit. Furthermore, filling of lanthanum into Fe0:1Co0:9Sb3 was attempted to decreasethethermalconductivity.Thelanthanum-filledFe0:1Co0:9Sb3 compoundsweresynthesizedfromrawmetal powders and LaSb powder by the pulse discharge sintering process. The optimum lanthanum content that leads to the maximum thermoelectric performance is discussed. The substitution of iron for cobalt improved the thermoelectric performance. The lanthanum-filling decreased the thermal conductivity at a low lanthanum content and led to higher thermoelectric performance in spite of low lanthanum content.