Thermoelectric properties of SnzCo8Sb24 skutterudites

Sn-filled CoSb3 skutterudite compounds were synthesized by the induction melting process. Formation of a single δδ-phase of the synthesized materials was confirmed by X-ray diffraction analysis. The temperature dependences of the Seebeck coefficient, electrical resistivity and thermal conductivity were examined in the temperature range of 300–700 K. Positive Seebeck and Hall coefficients confirmed pp-type conductivity. Electrical resistivity increased with increasing temperature, which shows that the Sn-filled CoSb3 skutterudite is a degenerate semiconductor. The thermal conductivity was reduced by Sn-filling because the filler atoms acted as phonon scattering centers in the skutterudite lattice. The lowest thermal conductivity was achieved in the composition of Sn0.25Co8Sb24.