Thermal Stability of High Performance Thermoelectric β‐Zn₄Sb₃ in Argon

Abstract

The stability of the high performance thermoelectric β‐Zn4Sb3 is investigated by multi‐temperature high resolution synchrotron powder X‐ray diffraction. Contrary to previous claims β‐Zn4Sb3 is not stable when heated in argon and degradation is observed already at 500 K. Nevertheless, the thermal stability of β‐Zn4Sb3 is much improved in argon (ca. 5 wt.‐% degradation after three heating cycles to 625 K) relative to heating in atmospheric air (ca. 60 wt.‐% degradation). Based on identification of the decomposition products two specific degradation processes are proposed, and the excellent stability of β‐Zn4Sb3 synthesized by zone melting (equilibrium method) is discussed in relation to the poor stability of material synthesized by thermal quenching (non‐equilibrium process). The room temperature peak widths and unit cell parameters change significantly after three heating cycles to 625 K suggesting that the β‐Zn4Sb3 phase diagram could be more complex than currently believed.

In Situ TEM Studies of Nanostructured Thermoelectric Materials: An Application to Mg‐Doped Zn4Sb3 Alloy

“…[4] Amongt heses trategies, nanocomposite TE materials, whichare designed to introduce nanometer-sized polycrystallinesa nd interfaces into bulk materials, can be considered as an effective approacht op roduce highperformance TE materials with low cost and large volume. [17,[28][29][30][31][32][33] Therefore, many studies have focused on the stability of Zn 4 Sb 3 under differentc onditions, for example in inert gas, [23,33,34] air, [34] static vacuum, [23] and dynamic vacuum. 5nm-10 mm, typically) grains on am ain matrix that creates extensivei nterfaces between the neighbouring nanoparticles, which allows significantly lower thermal conductivity.…”

Atomistic mechanisms governing structural stability change of zinc antimony thermoelectrics

“…[3] [7] [8] Despite its importance, only have a few attempts been made to address the thermal stability issue of thermoelectrics at their elevated working temperature. [9] [10] [11] [12] Zinc antimony is a typical 'phonon glass, electron crystal', one of the best thermoelectrics at moderate temperature. [13] [14] [15]In our previous experiments, it was found that β−Zn 4 Sb 3 samples become metastable around 425 K, but above 565K it recovers its stability.…”

Thermal stability and oxidation of layer-structured rhombohedral In3Se4 nanostructures

“…Thermal stability and oxidation of layer-structured rhombohedral In 3 The thermal stability and oxidation of layer-structured rhombohedral In 3 Se 4 nanostructures have been investigated. In-situ synchrotron X-ray diffraction in a sealed system reveals that In 3 Se 4 has good thermal stability up to 900 C. In contrast, In 3 Se 4 has lower thermal stability up to 550 or 200 C when heated in an atmosphere flushed with Ar or in air, respectively.…”

“…The thermal stability is a measure of the resistance of a material to transformation and/or decomposition at elevated temperatures and is an important intrinsic characteristics of any material. 1 For example, for a given material, having a superior thermal stability is important for high-temperature applications, such as thermoelectric energy conversion, [2][3][4] high-temperature catalytic reactions, 5 and for use in fuel cells. 6 Therefore, extensive investigations have been performed to explore the material thermal stability in bulk or nanoscale forms.…”

“…[7][8][9][10][11][12] The thermal stability of a material is not only determined by the intrinsic crystal structure but is also influenced by the conditions under which the heating is performed, such as the heating environment. 3 Oxidation, revealing the instability of materials under O 2 environment, always reduces the material thermal stability and results in the degradation of their intrinsic property. 13 On the other hand, oxidation can also be used to tune the photoelectric property of materials 14 and to intentionally design metal oxides with specific morphology.…”