Research Project: Termoelektrik Enerji Üretimi Uygulamaları İçin N-Tipi Zintl Fazlarının Tasarlanması
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Contributors
Funders
ID
TB.00404
Authors
Aydemir, Umut
Faculty Member
Publications
Stress/pressure-stabilized cubic polymorph of Li3Sb with improved thermoelectric performance
(Royal Society of Chemistry, 2021) Aydemir, Umut; Özen, Melis; Yahyaoğlu, Müjde; Soldi, Thomas; Candolfi, Christophe; Snyder, G. Jeffrey; Department of Chemistry; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Yes; College of Sciences; Research Center
Li3Sb has two polymorphs crystallizing in a face-centered cubic cell (c-Li3Sb; BiF3 structure type; space group Fm3m) and in a hexagonal unit cell (h-Li3Sb; Na3As structure type; space group P6(3)/mmc). c-Li3Sb was predicted to be a promising thermoelectric material based on recent first-principles studies; however, the experimental transport characteristics have remained unknown so far. Herein, successful preparation of c-Li3Sb is reported by stress-induced mechanochemical synthesis (high-energy ball milling) along with its high-temperature thermoelectric properties. Hexagonal Li3Sb (h-Li3Sb) was revealed to be the stable phase at ambient conditions, while it starts unexpectedly transforming to c-Li3Sb by ball milling or under 60 MPa applied pressure at room temperature. The transport properties measurements performed on two polycrystalline specimens evidence that c-Li3Sb behaves as a p-type degenerate semiconductor due to the formation of Li vacancies. In agreement with lattice dynamics calculations, c-Li3Sb exhibits very low lattice thermal conductivity despite the lightweight of Li. A zT value of around 0.3 was obtained at 550 K. Modelling suggests that the hole concentration should be reduced through aliovalent substitutions or under Li-rich conditions for further optimization. Although the strong air sensitivity of Li3Sb makes its use in thermoelectric applications challenging, this simple superionic binary provides an attractive experimental platform to elucidate the effect of stress/pressure on phase transitions as well as that of Fermi surface complexity on thermoelectric properties.
Key properties of inorganic thermoelectric materials - tables (version 1)
(Institute of Physics (IOP) Publishing, 2022) Aydemir, Umut; Özen, Melis; Sağlık, Kıvanç; Freer, R.; Ekren, D.; Ghosh, T.; Biswas, K.; Qiu, P.; Wan, S.; Chen, L.; Han, S.; Fu, C.; Zhu, T.; Ashiquzzaman Shawon, A.K.M.; Zevalkink, A.; Imasato, K.; Snyder, G.J.; Cardoso-Gil, R.; Svanidze, E.; Funahashi, R.; Powell, A.V.; Mukherjee, S.; Tippireddy, S.; Vaqueiro, P.; Gascoin, F.; Kyratsi, T.; Sauerschnig, P.; Mori, T.; Department of Chemistry; Graduate School of Sciences and Engineering; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Yes; College of Sciences; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
This paper presents tables of key thermoelectric properties, which define thermoelectric conversion efficiency, for a wide range of inorganic materials. The twelve families of materials included in these tables are primarily selected on the basis of well established, internationally-recognized performance and promise for current and future applications: tellurides, skutterudites, half Heuslers, Zintls, Mg-Sb antimonides, clathrates, FeGa3-type materials, actinides and lanthanides, oxides, sulfides, selenides, silicides, borides and carbides. As thermoelectric properties vary with temperature, data are presented at room temperature to enable ready comparison, and also at a higher temperature appropriate to peak performance. An individual table of data and commentary are provided for each family of materials plus source references for all the data.
