Research Project: Eriyik-Santrifüj Yöntemi Kullanılarak Cosb3, Mg2(Si,Sn) Ve Mg3(Sb,Bi) Termeoelektrik Malzemelerinin Verimliliklerinin Arttırılması; Kimyasal, Thermoelektrik Ve Mekanik Özelliklerinin İncelenmesi
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Contributors
Funders
ID
TB.00412
Authors
Aydemir, Umut
Faculty Member
Publications
Enhanced thermoelectric performance in Mg3+xSb1.5Bi0.49Te0.01 via engineering microstructure through melt-centrifugation
(Royal Society of Chemistry , 2021) Aydemir, Umut; Özen, Melis; Yahyaoğlu, Müjde; Candolfi, Christophe; Veremchuk, Igor; Kaiser, Felix; Burkhardt, Ulrich; Snyder, G. Jeffrey; Grin, Yuri; Department of Chemistry; Graduate School of Sciences and Engineering; KUBAM (Koç University Boron and Advanced Materials Application and Research Center); Yes; College of Engineering; College of Sciences; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
N-type Zintl phases with earth-abundant and non-toxic constituent elements have attracted intense research interest thanks to their high thermoelectric efficiencies in the mid-temperature range, exemplified by the recently discovered Mg3Sb2 material. In this study, the liquid phase is expelled from the microstructure of the optimized n-type phase Mg3+xSb1.5Bi0.49Te0.01 by applying a meltcentrifugation technique leading to the formation of lattice dislocations, grain boundary dislocations and increasing porosity. Additional phonon scattering mechanisms were introduced in the microstructure through this manufacturing method, resulting in a significant 50% reduction in the total thermal conductivity from similar to 1 W m(-1) K-1 to similar to 0.5 W m(-1) K-1 at 723 K. Combined with high power factors, this reduced heat transport leads to a dimensionless thermoelectric figure of merit, zT, value of similar to 1.64 at 723 K, 43% higher than the value obtained in untreated Mg3+xSb1.5Bi0.49Te0.01 (zT similar to 1.14 at 723 K). This peak zT value yields a predicted device ZT of 0.95, and a promising theoretical thermoelectric efficiency of about 12%. These results further underline the great potential of the lightweight Mg3Sb2 material for midtemperature energy harvesting via thermoelectric effects.
