Enhanced thermoelectric performance in Mg3+xSb1.5Bi0.49Te0.01via engineering microstructure through melt-centrifugation

Melis Ozen, Mujde Yahyaoglu, Christophe Candolfi, Igor Veremchuk, Felix Kaiser, Ulrich Burkhardt, G. Jeffrey Snyder, Yuri Grin, Umut Aydemir*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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 melt-centrifugation 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 ∼1 W m-1 K-1 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 ∼1.64 at 723 K, 43% higher than the value obtained in untreated Mg3+xSb1.5Bi0.49Te0.01 (zT ∼ 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 mid-temperature energy harvesting via thermoelectric effects.

Original languageEnglish (US)
Pages (from-to)1733-1742
Number of pages10
JournalJournal of Materials Chemistry A
Volume9
Issue number3
DOIs
StatePublished - Jan 21 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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