Synthesis and Thermoelectric Properties of Filled Skutterudite by a Solid Reaction Method

Abstract

The filled skutterudite compounds, M_yFe_xCo_4-xSb₁₂ (x=0-1.0, y=0-0.15, M=Ce, La, Y), were prepared by a new solid state reaction method using Co, Fe, Sb, CeCl₃.6H₂O, LaCl₃.6H₂O and YCl₃.6H₂O powders, and their thermoelectric properties were investigated. M_yFe_xCo_4-xSb₁₂ (x=0-1.0, y=0-0.15, M=Ce, La, Y) compounds showed p-type conduction. The electrical conductiviy (σ) increased with increasing Fe content. The Seebeck coefficient (α) increased with increasing Fe content for MFe_xCo_4-xSb₁₂, but decreased with increasing Fe content for Fe_xCo_4-x, Sb₁₂. The Lattice thermal conductivity (KL) decreased significantly with the substitution of Fe for Co and the filling of M (M=Ce, La, Y) into the Sb icosahedral voids, while the carrier thermal conductivity (Kcar) was not much affected by the Fe substitution and the M (Ce, La, Y) filling. The thermoelectric figure of merit was improved by the combinatior of Fe substitution and M (Ce, La, Y) filling.