Details

Autor(en) / Beteiligte

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

Titel

Enhanced thermoelectric performance in MgSbBiTe engineering microstructure through melt-centrifugation

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2021-01, Vol.9 (3), p.1733-1742

Erscheinungsjahr

2021

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• 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 Mg 3 Sb 2 material. In this study, the liquid phase is expelled from the microstructure of the optimized n-type phase Mg 3+ x Sb 1.5 Bi 0.49 Te 0.01 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 Mg 3+ x Sb 1.5 Bi 0.49 Te 0.01 ( 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 Mg 3 Sb 2 material for mid-temperature energy harvesting via thermoelectric effects. By applying the melt-centrifugation, porosity and dislocations are introduced in the microstructure of the n-type Zintl phase Mg 3+ x Sb 1.5 Bi 0.49 Te 0.01 leading to significantly low κ l (∼ 0.33 W m −1 K −1 at 723 K) and enhanced zT (∼ 1.64 at 723 K).