High-Temperature Transport Properties of Colusite Cu24T2V2Ge6S32 (T = Ni, Co)

Sulfur-based minerals have emerged as interesting candidates for thermoelectric applications at high temperatures, with tetrahedrites and colusites being two prominent examples. Here, we extend the investigations on the latter family by reporting on the synthesis and the high-temperature thermoelect...

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Bibliographic Details
Published in:Journal of electronic materials 2017-05, Vol.46 (5), p.2684-2690
Main Authors: Bouyrie, Y., Ohorodniichuk, V., Sassi, S., Masschelein, P., Dauscher, A., Candolfi, C., Lenoir, B.
Format: Article
Language:English
Subjects:
Characterization and Evaluation of Materials
Chemical Sciences
Chemistry and Materials Science
Electronics and Microelectronics
Instrumentation
Material chemistry
Materials Science
Optical and Electronic Materials
Solid State Physics
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Summary:Sulfur-based minerals have emerged as interesting candidates for thermoelectric applications at high temperatures, with tetrahedrites and colusites being two prominent examples. Here, we extend the investigations on the latter family by reporting on the synthesis and the high-temperature thermoelectric properties of two polycrystalline colusites, Cu 24 Ni 2 V 2 Ge 6 S 32 and Cu 24 Co 2 V 2 Ge 6 S 32 . Both samples were prepared by powder metallurgy and consolidated by spark plasma sintering. Successful substitution of Ni and Co for Cu was confirmed by powder x-ray diffraction and scanning electron microscopy which further revealed a homogeneous distribution of the elements within the colusite matrix. The electrical resistivity and thermopower values measured in the Ni sample indicate a more pronounced metallic character with respect to the Co sample. These two samples exhibit very low lattice thermal conductivities of the order of 0.5 W m −1  K −1 at 690 K. Despite this remarkable property, the Ni and Co concentrations studied here did not give rise to enhanced ZT values relative to the previously reported parent compound Cu 26 V 2 Ge 6 S 32 , with a peak ZT value of 0.5 at 690 K achieved in the Ni sample.
ISSN:0361-5235
1543-186X
DOI:10.1007/s11664-016-4893-7