Development of new high temperature power generating couples for the Advanced Thermoelectric Converter (ATEC)

Li, Billy; Firdosy, Samad; Paik, Jong-Ah; Huang, C.‐K.; Cheng, Bijang; Gogna, P.; Nakatsukasa, George; Caillat, T.; Fleurial, Jean‐Pierre; Ravi, Vilupanur A.; Nesmith, Bill; Ewell, Richard; Brandon, Erik J.

doi:10.2514/6.2010-7004

Cited by 6 publications

(3 citation statements)

References 5 publications

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“…To investigate the possible reaction pathways, polycrystalline Yb 11 Sb 10 was prepared. Yb 14 MnSb 11 was chosen as the synthetic target because of its excellent properties as a thermoelectric material in comparison to the Al analogue. − ,,, Figure shows the PXRD of high-energy milled powder and after annealing of the constituents, Yb 11 Sb 10 , MnSb, Yb, and YbH 2 , to make Yb 14 MnSb 11 . After milling, the reactants have changed from their crystalline forms to something more amorphous.…”

Section: Resultsmentioning

confidence: 99%

“…This complex phase contains eight formula units per unit cell with each formula unit containing 13 Yb +2 cations, 1 Yb +3 cation, 1 [MgSb 4 ] −10 tetrahedron, 1 Sb 3 –7 linear unit, and 4 Sb –3 anions. Yb 14 MgSb 11 and the isostructural Yb 14 MnSb 11 both exhibit excellent high-temperature thermoelectric properties and are under consideration for implementation in radioisotope thermal electric generators for space exploration. − Because of the wide interest in thermoelectric modules for waste heat recovery, an efficient synthetic route to high-purity phases with precise control over stoichiometry will have a significant impact on increasing the progress toward even higher-efficiency materials. − …”

Section: Introductionmentioning

confidence: 99%

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2 + 2 = 3: Making Ternary Phases through a Binary Approach

et al. 2022

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Synthetic organic chemists have a large toolbox of named reactions to form structural motifs through a retrosynthetic approach when targeting a complex molecule. On the other hand, a comparatively complex inorganic compound may be made through simple mechanochemical reactions of the elements followed by annealing. For complex phases that involve more than two elements, the simple mechanochemical process can be complex with many competing phases, which can negatively impact desired properties. This point has been made recently with a revelation of improved properties of thermoelectric materials upon the removal of impurities. Compounds of the Yb14AlSb11 structure type represent complex Zintl phases with exceptional high-temperature thermoelectric properties but are difficult to prepare in high purity. In this work, a quenching study was used to elucidate the pathway taken by reactions from the elements to form the complex ternary phase, Yb14AlSb11. Through that study, two Yb–Sb binary phases, Yb11Sb10 and Yb4Sb3, were identified as intermediates in the reaction. These two Yb–Sb binaries were investigated for use as reactive precursors to form Yb14MnSb11 in reactions with MnSb. Through this pseudoretrosynthetic approach, reactions from Yb4Sb3 allowed for the synthesis of high-purity Yb14MnSb11 and Yb14MgSb11 through balanced, stoichiometric reactions. The apparent Yb2O3 (∼1%) impurity found in these products was systematically reduced with x in the series Yb14‑x MnSb11 (x = 0–0.05), suggesting that the main phase is inherently Yb-deficient and showing the high degree of control obtained through this synthetic approach. The stoichiometric sample of Yb14MgSb11 has a peak zT of 1.3 at 1175 K, and the stoichiometric sample of Yb14MnSb11 has a peak zT of 1.2 at 1275 K. This approach to solid-state synthesis provides reproducible products from balanced stoichiometric reactants to form high-purity complex structure types and can be adapted to other difficult ternary systems.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

2 + 2 = 3: Making Ternary Phases through a Binary Approach

et al. 2022

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“…The large, complex unit cell lends itself to low thermal conductivities while the high symmetry of the crystal structure leads to degenerate bands and a high density of states near the valence band edge. − The high free carrier concentration gives these materials low electrical resistivity while the high density of states near the Fermi level helps to boost Seebeck coefficients through high valley degeneracy. All this combines to make Yb 14 MnSb 11 a state-of-the-art high-temperature thermoelectric material with zT s of 1.2–1.3 at 1273 K and is being considered for the next generation of RTG. − While the performance of these materials is promising, oxidation from small amounts of residual oxygen within the RTG can be extremely detrimental to performance and stability.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Thermoelectric and Oxidation Properties in Lu-Substituted Yb₁₄MnSb₁₁

Justl

Bux

Kauzlarich

2022

ACS Appl. Energy Mater.

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Yb14MnSb11 is one of the state-of-the-art high-temperature p-type thermoelectric materials with reported zTs of 1.2–1.3 at 1273 K. Site substitution of Yb14MnSb11 provides a means to control carrier concentration and impacts the oxidation kinetics. Substitution of Lu3+ for Yb2+ in Yb14MnSb11 single crystals has been shown to provide faster oxidation kinetics compared with the pristine phase, and it has been speculated that this may lead to surface passivation. Polycrystalline samples of Yb14–x Lu x MnSb11 were synthesized from the elements and through a route utilizing YbH2, MnSb, and Yb4Sb3 as reactive precursors. The solubility of Lu was found to be less than x = 0.5, and at that composition and above LuSb impurities are observed in the powder X-ray diffraction. Because Lu3+ is substituting for Yb2+ in a p-type system, there is an increase in both the electrical resistivity and Seebeck coefficient with Lu substitution. As Yb14MnSb11 has been predicted to be optimally doped ∼1.5 × 1021 h+ cm–3, this reduction in carrier concentration in the solid solution of Yb14–x Lu x MnSb11 decreases the peak zT. Oxidation of Yb13.7Lu0.3MnSb11 as a function of temperature was studied. At low temperatures, the Lu-substituted sample may have improved oxidation resistance through forming a passivating oxide film on the surface.

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Thermoelectric Properties of Zintl Antimonides

Kazem

Kauzlarich

2016

Including Actinides

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Development of new high temperature power generating couples for the Advanced Thermoelectric Converter (ATEC)

Cited by 6 publications

References 5 publications

2 + 2 = 3: Making Ternary Phases through a Binary Approach

2 + 2 = 3: Making Ternary Phases through a Binary Approach

Evolution of Thermoelectric and Oxidation Properties in Lu-Substituted Yb₁₄MnSb₁₁

Thermoelectric Properties of Zintl Antimonides

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Development of new high temperature power generating couples for the Advanced Thermoelectric Converter (ATEC)

Cited by 6 publications

References 5 publications

2 + 2 = 3: Making Ternary Phases through a Binary Approach

2 + 2 = 3: Making Ternary Phases through a Binary Approach

Evolution of Thermoelectric and Oxidation Properties in Lu-Substituted Yb14MnSb11

Thermoelectric Properties of Zintl Antimonides

Contact Info

Product

Resources

About

Evolution of Thermoelectric and Oxidation Properties in Lu-Substituted Yb₁₄MnSb₁₁