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

Autor(en)

G. Rogl, A. Grytsiv, P. Heinrich, E. Bauer, P. Kumar, N. Peranio, O. Eibl, J. Horky, M. Zehetbauer, P. Rogl

Abstrakt

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(en)

Institut für Physikalische Chemie, Physik Nanostrukturierter Materialien

Externe Organisation(en)

Eberhard Karls Universität Tübingen, Technische Universität Wien

Journal

Acta Materialia

Band

91

Seiten

227-238

Anzahl der Seiten

12

ISSN

1359-6454

DOI

https://doi.org/10.1016/j.actamat.2015.03.008

Publikationsdatum

06-2015

Peer-reviewed

Ja

ÖFOS 2012

104017 Physikalische Chemie, 210004 Nanomaterialien

Schlagwörter

ASJC Scopus Sachgebiete

Electronic, Optical and Magnetic Materials, Ceramics and Composites, Metals and Alloys, Polymers and Plastics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/3de12f1d-bbfc-4852-ab28-f4cd9c9e3482