Thermoelectric Properties of CeyFexCo4−xSb12 Prepared by a Solid State Reaction

The filled skutterudite compounds, CeyFexCo4−xSb12(x=0-1.0, y=0-0.15), were prepared from powders of Co, Fe, Sb and CeCl3·6H2O by solid state reaction, and their thermoelectric properties were investigated. CeyFexCo4−xSb12(x=0-1.0, y=0-0.15) compounds showed p-type conductivity. Carrier concentration (p) increased with increasing substitution Fe for Co site, and decreased with increasing Ce content. Electrical conductivity (σ) increased with increasing Fe content. The seebeck coefficient (α) increased with increasing Fe content for CeFexCo4−xSb12, but decreased with increasing Fe content for FexCo4−xSb12. Thermal conductivity (κ) decreased significantly with the substitution of Fe for Co and filling of Ce into Sb dodecahedron voids. The thermoelectric figure of merit was improved by the combination of Fe substitution and Ce filling. The maximum ZT value of 0.8 was obtained for Ce0.12Fe0.71Co3.29Sb12 at 750 K.