Thermal stability of Mg3Sb1.475Bi0.475Te0.05 high performance n-type thermoelectric investigated through powder X-ray diffraction and pair distribution function analysis

Jørgensen, Lasse Rabøl; Zhang, Jiawei; Zeuthen, Christian Bonar; Iversen, Bo B.

doi:10.1039/c8ta06544f

Cited by 47 publications

(39 citation statements)

References 23 publications

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“…With continuous experimental efforts, a low-temperature zT of~0.9 at 323 K and a peak zT of~1.85 at 723 K have been achieved so far in n-type (Mn, Te)-codoped Mg 3 Sb 1.5 Bi 0.5 . 66,71 In addition to the intensive developments in TE performance, the thermal stability of n-type Te-doped Mg 3 Sb 1.5 Bi 0.5 was investigated by Jørgensen et al 72 using synchrotron powder X-ray diffraction and X-ray total scattering, where a clear evolution of bismuth as a secondary phase was observed in the powdered sample during thermal cycling.…”

Section: Multi-valley Conduction Bands Complex Fermi Surface and Exmentioning

confidence: 99%

“…1), [53][54][55] comparable or even superior to the commercial n-type TE materials, such as Bi 2 Te 3 and PbTe. Hence, significant research efforts [56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] on this promising material system are currently ongoing. Theoretically, electronic structures, 20,74-77 chemical bonding, 11,12,78,79 defects, 55,60,61,80 and phonon-related properties [81][82][83][84] have been extensively studied to understand the transport properties.…”

Section: Introductionmentioning

confidence: 99%

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Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

2019

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Over the past two decades, we have witnessed a strong interest in developing Mg 3 Sb 2 and related CaAl 2 Si 2 -type materials for lowand intermediate-temperature thermoelectric applications. In this review, we discuss how computations coupled with experiments provide insights for understanding chemical bonding, electronic transport, point defects, thermal transport, and transport anisotropy in these materials. Based on the underlying insights, we examine design strategies to guide the further optimization and development of thermoelectric Mg 3 Sb 2 -based materials and their analogs. We begin with a general introduction of the Zintl concept for understanding bonding and properties and then reveal the breakdown of this concept in AMg 2 X 2 with a nearly isotropic three-dimensional chemical bonding network. For electronic transport, we start from a simple yet powerful atomic orbital scheme of tuning orbital degeneracy for optimizing p-type electrical properties, then discuss the complex Fermi surface aided by high valley degeneracy, carrier pocket anisotropy, and light conductivity effective mass responsible for the exceptional n-type transport properties, and finally address the defect-controlled carrier density in relation to the electronegativity and bonding character. Regarding thermal transport, we discuss the insight into the origin of the intrinsically low lattice thermal conductivity in Mg 3 Sb 2 . Furthermore, the anisotropies in electronic and thermal transport properties are discussed in relation to crystal orbitals and chemical bonding. Finally, some specific challenges and perspectives on how to make further developments are presented.npj Computational Materials (2019) 5:76 ; https://doi.

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Section: Multi-valley Conduction Bands Complex Fermi Surface and Exmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

2019

Self Cite

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“…Despite exhibiting a high zT of 1.5 at around 700 K, the power generators made from n -type Mg 3 Sb 2- x Bi x might be challenging owing to the decomposition of the compounds and possible deterioration of electrical properties at elevated temperatures [ 90 , 91 ]. Fortunately, even near RT, n -type Mg 3 Sb 2- x Bi x also shows good zT of around 0.8 ( Figure 1(b) ), making it a promising alternative to the state-of-the-art n -type Bi 2 Te 3- x Se x for solid-state cooling application.…”

Section: Introductionmentioning

confidence: 99%

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective

Zhao

et al. 2020

Research

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Since the first successful implementation of n-type doping, low-cost Mg3Sb2-xBix alloys have been rapidly developed as excellent thermoelectric materials in recent years. An average figure of merit zT above unity over the temperature range 300–700 K makes this new system become a promising alternative to the commercially used n-type Bi2Te3-xSex alloys for either refrigeration or low-grade heat power generation near room temperature. In this review, with the structure-property-application relationship as the mainline, we first discuss how the crystallographic, electronic, and phononic structures lay the foundation of the high thermoelectric performance. Then, optimization strategies, including the physical aspects of band engineering with Sb/Bi alloying and carrier scattering mechanism with grain boundary modification and the chemical aspects of Mg defects and aliovalent doping, are extensively reviewed. Mainstream directions targeting the improvement of zT near room temperature are outlined. Finally, device applications and related engineering issues are discussed. We hope this review could help to promote the understanding and future developments of low-cost Mg3Sb2-xBix alloys for practical thermoelectric applications.

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“…Studies of the stability of TE materials typically use experimental conditions that do not resemble an operating module. This primarily involves powder X-ray diffraction (PXRD) studies at elevated temperatures, or thermal cycling, using various atmospheres (Jørgensen et al, 2018a(Jørgensen et al, , 2018bPedersen & Iversen, 2008;Pedersen et al, 2006Pedersen et al, , 2010Fischer et al, 2018;Reardon et al, 2017;. Some studies have exposed TE materials to (semi)realistic conditions but they have not simultaneously characterized the structural or TE properties (operando) (Reardon et al, 2017;Hung et al, 2017;Yin et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Operando X-ray scattering study of thermoelectric β-Zn₄Sb₃

Jørgensen

Zeuthen

Borup

et al. 2020

IUCrJ

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The application of thermoelectrics for energy harvesting depends strongly on operational reliability and it is therefore desirable to investigate the structural integrity of materials under operating conditions. We have developed an operando setup capable of simultaneously measuring X-ray scattering data and electrical resistance on pellets subjected to electrical current. Here, operando investigations of β-Zn4Sb3 are reported at current densities of 0.5, 1.14 and 2.3 A mm−2. At 0.5 A mm−2 no sample decomposition is observed, but Rietveld refinements reveal increased zinc occupancy from the anode to the cathode demonstrating zinc migration under applied current. At 1.14 A mm−2 β-Zn4Sb3 decomposes into ZnSb, but pair distribution function analysis shows that Zn2Sb2 units are preserved during the decomposition. This identifies the mobile zinc in β-Zn4Sb3 as the linkers between the Zn2Sb2 units. At 2.3 A mm−2 severe Joule heating triggers transition into the γ-Zn4Sb3 phase, which eventually decomposes into ZnSb, demonstrating Zn ion mobility also in γ-Zn4Sb3 under electrical current.

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Thermal stability of Mg₃Sb_1.475Bi_0.475Te_0.05 high performance n-type thermoelectric investigated through powder X-ray diffraction and pair distribution function analysis

Abstract: The thermal stability of the high performance n-type Te-doped Mg3Sb1.5Bi0.5 system is investigated.

Cited by 47 publications

References 23 publications

Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective

Operando X-ray scattering study of thermoelectric β-Zn₄Sb₃

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Thermal stability of Mg3Sb1.475Bi0.475Te0.05 high performance n-type thermoelectric investigated through powder X-ray diffraction and pair distribution function analysis

Abstract: The thermal stability of the high performance n-type Te-doped Mg3Sb1.5Bi0.5 system is investigated.

Cited by 47 publications

References 23 publications

Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

Insights into the design of thermoelectric Mg3Sb2 and its analogs by combining theory and experiment

High-Performance Mg 3 Sb 2- x Bi x Thermoelectrics: Progress and Perspective

Operando X-ray scattering study of thermoelectric β-Zn4Sb3

Contact Info

Product

Resources

About

Thermal stability of Mg₃Sb_1.475Bi_0.475Te_0.05 high performance n-type thermoelectric investigated through powder X-ray diffraction and pair distribution function analysis

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective

Operando X-ray scattering study of thermoelectric β-Zn₄Sb₃