Synthesis and thermoelectric properties of new partially filled CaxCo4Sb12 skutterudites

M. Puyet1, B. Lenoir1, A. Dauscher1, M. Dehmas2, P. Weisbecker2, S.J. Clarke3, C. Stiewe4, E. Müller4

1Laboratoire de Physique des Matériaux, UMR7556, ENSMN, Parc de Saurupt, 54042 Nancy, France

2Laboratoire de Science et Génie des Matériaux et de Métallurgie , Ecole des Mines de Nancy 54042 Nancy Cedex

3University of Oxford, South Parks Road, Oxford, OXI 3QR, United Kingdom

4German Aerospace Center (DLR), Institute of Materials Research, Linder Hoehe, 51147 Cologne, Germany

Materials of skutterudite structure are very promising for thermoelectric applications. Partially filled Co4Sb12 compounds have received particularly attention. Several kinds of atoms were introduced in the voids of the crystalline structure in order to decrease substantially the thermal conductivity.

It this communication, we report on the synthesis and on the transport properties of new partially filled CaxCo4Sb12 compounds. The synthesis has been carried out by a conventional metallurgical route. Rietveld refinement on neutron powder diffraction patterns have been performed to prove that the Ca atoms are in the voids of the structure. The filled fraction limit is found to be 0.2.

Electrical and thermal transport properties were performed in the temperature range 300-800 K. The effect of Ca on the transport properties is discussed in detail. The potential of this new family of compounds for thermoelectric applications at high temperature is also presented.