N-Type skutterudites (R,Ba,Yb) _yCo ₄Sb ₁₂ (R = Sr, La, Mm, DD, SrMm, SrDD) approaching ZT ≈ 2.0

Author(s)

G. Rogl, A. Grytsiv, P. Rogl, N. Peranio, E. Bauer, M. Zehetbauer, O. Eibl

Abstract

The influence of various fillers R (R = Sr, La, Mm, DD, SrMm, SrDD with Mm standing for mischmetal and DD for didymium) on the physical properties of the triple- and multifilled n-type skutterudites with the nominal composition (R

_0.33Ba

_0.33Yb

_0.33)

_0.35Co

₄Sb

_12.3 is investigated. In comparison to values from previous works of the authors and from the literature it is demonstrated that even small changes in the filling fractions of the fillers as well as in the total filling level influence the power factor and the thermal conductivity. These skutterudites, partially filled with multiple fillers of different chemical nature, can achieve high power factors (>6 mW m

^-1 K

^-2 at 823 K) and at the same time low thermal conductivity, resulting in ZT = 1.4 at 823 K. On the contrary, Yb

₂O

₃ as a secondary phase in (Sr

_0.25Ba

_0.25Yb

_0.50)

_0.5Co

₄Sb

_12.5 significantly reduces the thermoelectric (TE) performance due to a decreased power factor and an increased lattice thermal conductivity. However, a homogeneous nanoscale distribution of these impurities substantially improves the TE performance, resulting in ZT values of ∼1.6 at 835 K. The ZT value of this skutterudite could be further enhanced to 1.9 (at 835 K) after severe plastic deformation via high-pressure torsion.

Organisation(s)

Department of Physical Chemistry, Physics of Nanostructured Materials

External organisation(s)

Eberhard Karls Universität Tübingen, Technische Universität Wien

Journal

Acta Materialia

Volume

63

Pages

30-43

No. of pages

14

ISSN

1359-6454

DOI

https://doi.org/10.1016/j.actamat.2013.09.039

Publication date

01-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

104017 Physical chemistry, 210006 Nanotechnology

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/ntype-skutterudites-rbayb-yco-4sb-12-r--sr-la-mm-dd-srmm-srdd-approaching-zt--20(e8e1410b-6b75-446f-901c-5659251efaa0).html