Improved thermoelectric performance of n-type Ca and Ca-Ce filled skutterudites

Journal Article · Sun Dec 28 04:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4904187· OSTI ID:22399154

Thompson, Daniel R.; Liu, Chang; Ellison, Nicole D. ^[1]; Salvador, James R.; Meyer, Martin S.; Haddad, Daad B. ^[2]; Wang, Hsin; Cai, W. ^[3]

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1. Optimal CAE, Plymouth, Michigan 48170 (United States)
2. General Motors Research and Development, Warren, Michigan 48090 (United States)
3. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

Thermoelectric (TE) technology for use in automotive waste heat recovery is being advanced by General Motors with support from the US Department of Energy. Skutterudites are a very promising material for this application of TE technology due to their superior mechanical properties and good TE performance. Double-filled Yb{sub x}Ba{sub y}Co{sub 4}Sb{sub 12} with ZT values around 1.1 at 750 K are the best performing n-type skutterudites produced on a large scale using an economically viable approach of melt spinning (MS) in conjunction with spark plasma sintering (SPS). Another economical production method on the tons scale, the melt quench annealing (MQA) technique, has been recently claimed by Treibacher Industrie AG, further information is available [G. Rogl et al., Acta Mater. 76, 434–448 (2014)]. A possible hurdle to commercial implementation of these materials is the use of rare earths as the fillers to reduce thermal conductivity and improve the electrical transport properties. It will be shown herein that skutterudites double-filled with Ca and Ce, both of which are lower-cost fillers, display markedly different TE properties depending on whether they are produced by MQA or MS + SPS synthesis techniques. Ca and Ce double-filled skutterudites prepared by MS + SPS have TE properties that are superior to the same compositions prepared by MQA and that are comparable to the best performing Yb and Ba filled materials. Furthermore, the results of this study suggest that the unusually poor transport properties of MQA Ca-filled skutterudites can be ascribed to deleterious secondary phases, which is contrary to reports in the literature attempting to explain these irregularities via band structure features.

• OSTI ID: 22399154
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 24 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANNEALING
ANTIMONIDES
BARIUM COMPOUNDS
CERIUM
COBALT COMPOUNDS
COMPARATIVE EVALUATIONS
ELECTRIC CONDUCTIVITY
FILLERS
MECHANICAL PROPERTIES
N-TYPE CONDUCTORS
PERFORMANCE
SINTERING
SYNTHESIS
THERMAL CONDUCTIVITY
YTTERBIUM COMPOUNDS