New bulk p-type skutterudites DD0.7Fe2.7Co1.3Sb12-xXx (X = Ge, Sn) reaching ZT > 1.3

Author(s)
G. Rogl, A. Grytsiv, P. Heinrich, E. Bauer, P. Kumar, N. Peranio, O. Eibl, J. Horky, M. Zehetbauer, P. Rogl
Abstract

The best p-type skutterudites so far are didymium filled, Fe/Co substituted, Sb-based skutterudites. Substitution at the Sb-sites influences the electronic structure, deforms the Sb

4-rings, enhances the scattering of phonons on electrons and impurities and in this way reduces the lattice thermal conductivity. In this paper we study structural and transport properties of p-type skutterudites with the nominal composition DD

0.7Fe

2.7Co

1.3Sb

11.7{Ge/Sn}

0.3, which were prepared by a rather fast reaction-annealing-melting technique. The Ge-doped sample showed impurities, which did not anneal out completely and even with ZT > 1 the result was not satisfying. However, the single-phase Sn-doped sample, DD

0.7Fe

2.7Co

1.3Sb

11.8Sn

0.2, showed a lower thermal and lattice thermal conductivity than the undoped skutterudite leading to a higher ZT = 1.3, hitherto the highest ZT for a p-type skutterudite. Annealing at 570 K for 3 days proved the stability of the microstructure. After severe plastic deformation (SPD), due to additionally introduced defects, an enhancement of the electrical resistivity was compensated by a significantly lower thermal conductivity and the net effect led to a record high figure of merit: ZT = 1.45 at 850 K for DD

0.7Fe

2.7Co

1.3Sb

11.8Sn

0.2.

Organisation(s)
Department of Physical Chemistry, Physics of Nanostructured Materials
External organisation(s)
Eberhard Karls Universität Tübingen, Technische Universität Wien
Journal
Acta Materialia
Volume
91
Pages
227-238
No. of pages
12
ISSN
1359-6454
DOI
https://doi.org/10.1016/j.actamat.2015.03.008
Publication date
06-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
104017 Physical chemistry, 210004 Nanomaterials
Keywords
ASJC Scopus subject areas
Electronic, Optical and Magnetic Materials, Ceramics and Composites, Metals and Alloys, Polymers and Plastics
Portal url
https://ucris.univie.ac.at/portal/en/publications/new-bulk-ptype-skutterudites-dd07fe27co13sb12xxx-x--ge-sn-reaching-zt--13(3de12f1d-bbfc-4852-ab28-f4cd9c9e3482).html