Nb‐Mediated Grain Growth and Grain‐Boundary Engineering in Mg<sub>3</sub>Sb<sub>2</sub>‐Based Thermoelectric Materials

Luo, Ting; Kuo, Jimmy Jiahong; Griffith, Kent J.; Imasato, Kazuki; Cojocaru‐Mirédin, Oana; Wuttig, Matthias; Gault, Baptiste; Yu, Yuan; Snyder, G. Jeffrey

doi:10.1002/adfm.202100258

Cited by 69 publications

(49 citation statements)

References 48 publications

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“…Based on the transport modeling for the electrical properties, Nb enrichment appears to lower the GB resistivity. [39] This work not only validates the existence of GB scattering in Mg 3 Sb 2 but also elucidates the previously unknown effect of metallic addition in promoting grain development and decreasing GB resistivity. [37,38]…”

Section: Nmr Xas and Apt Show No Sign Of Metal Incorporation To Chang...supporting

confidence: 75%

“…However, microstructural studies using diffraction, X‐ray absorption spectroscopy (XAS), nuclear magnetic resonance (NMR) spectroscopy, energy‐dispersive X‐ray spectroscopy, and atom probe tomography (APT) have contradicted the ionized‐impurity hypothesis. [ 39,78 ] These experimental analyses demonstrated that Nb does not enter the

{Mg}_{3} {Sb}_{2}

matrix and Nb stays metallic. The reason why the improvement was initially associated with the suppression of ionized impurity scattering is related to the grain boundary effects discussed in this article.…”

Section: Thermally Activated Conductivity By Grain Boundary Effectmentioning

confidence: 96%

“…Reduction in thermal conductivity with decreasing nominal Mg content in systems containing transition metal additives such as

{Mg}_{3.2 - x} {Nb}_{x} {Sb}_{1.5} {Bi}_{0.49} {Te}_{0.01}

[ 37 ] and

{Mg}_{3 + x} {normalM}_{0.1} {Sb}_{1.5} {Bi}_{0.49} {Te}_{0.01}

(M = Fe, Co, Hf, and Ta) [ 38 ] could also be explained similarly. Recent studies showed by combining atom probe tomography (APT) and nuclear magnetic resonance (NMR) spectroscopy [ 39 ] that some of the additives do not necessarily enter the

{Mg}_{3} X_{2}

structure and get excluded from the matrix phase, possibly leading to similar effects on transport properties as excess elemental Mg. In summary, these results demonstrate that although an excess of Mg in the nominal composition can ensure n‐type conduction in

{Mg}_{3} X_{2}

compounds, too much excess Mg is detrimental to the thermal conductivity of the material.…”

Section: Effects Of Excess Mgmentioning

confidence: 99%

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Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Imasato

Wood

Anand

et al. 2022

Adv Energy and Sustain Res

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n‐Type Mg3Sb2‐Mg3Bi2 alloys are some of the most promising thermoelectric materials in the low–mid temperature range. While discovered relatively recently, these materials have garnered intense attention, and numerous papers from the international thermoelectric community have been published in a relatively short period of time. As with all materials, detailed insights into the underlying mechanisms that contribute to these alloys’ distinguished thermoelectric properties are important for future researchers to push the performance of this material to new heights. Herein, experimental studies on the role defects, synthesis conditions, electronic band structure, and microstructure along with future prospects arecompiled to establish a guide for fully exploiting the potential of this material system. Considering the limited number of n‐type thermoelectric materials with this performance for low‐grade heat recovery and cooling technologies, further development of the Mg3Sb2‐Mg3Bi2 alloys is an important step toward commercial applications of thermoelectric materials, including cooling technologies and waste heat recovery applications.

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Section: Nmr Xas and Apt Show No Sign Of Metal Incorporation To Chang...supporting

confidence: 75%

{Mg}_{3} {Sb}_{2}

Section: Thermally Activated Conductivity By Grain Boundary Effectmentioning

confidence: 96%

“…Reduction in thermal conductivity with decreasing nominal Mg content in systems containing transition metal additives such as

{Mg}_{3.2 - x} {Nb}_{x} {Sb}_{1.5} {Bi}_{0.49} {Te}_{0.01}

[ 37 ] and

{Mg}_{3 + x} {normalM}_{0.1} {Sb}_{1.5} {Bi}_{0.49} {Te}_{0.01}

{Mg}_{3} X_{2}

{Mg}_{3} X_{2}

compounds, too much excess Mg is detrimental to the thermal conductivity of the material.…”

Section: Effects Of Excess Mgmentioning

confidence: 99%

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Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Imasato

Wood

Anand

et al. 2022

Adv Energy and Sustain Res

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“…As a result, the n-type Mg 3+δ (Sb,Bi) 2 -based compounds with an exceptional ZT of 1.51 at 716 K were successfully fabricated. [29] Based on this, many strategies were explored to further improve the ZTs of n-type Mg 3+δ (Sb,Bi) 2 up to ≈1.85, such as substituting the Mg site by Mn, [31,39,40] Nd, [23] Co, [41] Y, [42] Sc, [43] Gd, [44] and Nb, [45,46] substituting the Sb/Bi site by Te, [29,30,32,41,43,45] as well as grain-boundary engineering [46,47] and valley anisotropy. [48] However, there are still many issues and unclear points that need to be solved, such as the fundamental doping mechanism of Y on the Mg site, as well as the expensive Te used for substituting Sb/Bi.…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Band and Nanostructure Engineering on the Boosted Thermoelectric Performance of n‐Type Mg₃₊_δ(Sb, Bi)₂ Zintls

Liang

Shi

Peng

et al. 2022

Advanced Energy Materials

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Thermoelectric Mg3+δ(Sb, Bi)2 Zintls have attracted significant attention because of their high‐performing, eco‐friendly, and cost‐effective features, but their thermoelectric properties still need improvement for application to practical devices. Here an outstanding ZT of ≈1.87 at 773 K and a high average ZT of ≈1.2 in n‐type Y‐doped Mg3.2Sb1.5Bi0.49Se0.01 are reported, both of which rank as top values among the reported literature. First‐principles calculations indicate that substituting the Mg site with Y shifts the Fermi level into the conduction band and simultaneously narrows the bandgap, both strengthening the n‐type semiconducting feature and boosting the electron carrier density of Mg3.2Sb1.5Bi0.49Se0.01. A high power factor of ≈21.4 µW cm–1 K–2 is achieved at 773 K in Mg3.18Y0.02Sb1.5Bi0.49Se0.01, benefiting from the rationally tuned carrier density of ≈7.7 × 1019 cm–3 at this temperature. In addition, the doped Ys act as point defects to cause significant lattice distortions and strains, confirmed by comprehensive micro/nanostructure characterizations. These lattice imperfections suppress the lattice thermal conductivity to ≈0.41 W m–1 K–1 at 773 K, leading to such a high ZT. Furthermore, a high energy conversion efficiency of ≈13.8% is predicted by a temperature gradient of 450 K, indicating a great potential to be applied to practical devices for mid‐temperature applications.

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“…In the polycrystalline samples, the suppression of grain boundary scattering can be conducted by increasing the grain size or doping Mn, Nb, etc. [20][21][22] Recently, Mg 3 (Sb,Bi) 2 single crystal was successfully synthesized. Due to the removed grain boundary resistance, Mg 3 Sb 2 single crystal can exhibit a large enhanced zT near room temperature by more than 100%, compared to the polycrystalline samples.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study on Thermoelectric Performance of N‐Type Mg₃(Sb,Bi)₂ Single Crystal for Cooling or Power Generation

Zhang

Zheng

et al. 2022

Advcd Theory and Sims

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Mg 3 Sb 2 -based Zintl compounds have been paid much attention in recent years because of their high peak figure of merit (zT), however, there is room for the improvement of the average zT. In this work, the thermoelectric performance of Mg 3 (Sb,Bi) 2 single crystal by using density functional theory is investigated. The optimal carrier concentration (n) of Mg 3 SbBi is 2 × 10 19 to 3 × 10 20 cm -3 at 100−700 K. At the n of 3 × 10 19 cm -3 , it can exhibit a high average zT of ≈1.27 at cold-side temperature (T c ) of 300 K and hot-side temperature (T h ) of 700 K, and the electrical transport performance can be further improved by increasing the n. When the optimal n is reached, the maximum average zT of Mg 3 SbBi at T c of 100 K and T h of 300 K can be up to 0.54, which is comparable to that of state-of-the-art Bi 2 (Te,Se) 3 . Because the decreasing trend of the optimal n with temperature, the maximum low-temperature thermoelectric performance is easier to be achieved by less extrinsic doping. This work reveals the great potential of Mg 3 (Sb,Bi) 2 single crystal for thermoelectric cooling or power generation, which is expected to provide useful guidance for thermoelectric devices.

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Nb‐Mediated Grain Growth and Grain‐Boundary Engineering in Mg₃Sb₂‐Based Thermoelectric Materials

Cited by 69 publications

References 48 publications

Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Synergistic Effect of Band and Nanostructure Engineering on the Boosted Thermoelectric Performance of n‐Type Mg₃₊_δ(Sb, Bi)₂ Zintls

Theoretical Study on Thermoelectric Performance of N‐Type Mg₃(Sb,Bi)₂ Single Crystal for Cooling or Power Generation

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Nb‐Mediated Grain Growth and Grain‐Boundary Engineering in Mg3Sb2‐Based Thermoelectric Materials

Cited by 69 publications

References 48 publications

Understanding the High Thermoelectric Performance of Mg3Sb2‐Mg3Bi2 Alloys

Understanding the High Thermoelectric Performance of Mg3Sb2‐Mg3Bi2 Alloys

Synergistic Effect of Band and Nanostructure Engineering on the Boosted Thermoelectric Performance of n‐Type Mg3+δ(Sb, Bi)2 Zintls

Theoretical Study on Thermoelectric Performance of N‐Type Mg3(Sb,Bi)2 Single Crystal for Cooling or Power Generation

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Resources

About

Nb‐Mediated Grain Growth and Grain‐Boundary Engineering in Mg₃Sb₂‐Based Thermoelectric Materials

Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Understanding the High Thermoelectric Performance of Mg₃Sb₂‐Mg₃Bi₂ Alloys

Synergistic Effect of Band and Nanostructure Engineering on the Boosted Thermoelectric Performance of n‐Type Mg₃₊_δ(Sb, Bi)₂ Zintls

Theoretical Study on Thermoelectric Performance of N‐Type Mg₃(Sb,Bi)₂ Single Crystal for Cooling or Power Generation