Designing high-performance n-type Mg<sub>3</sub>Sb<sub>2</sub>-based thermoelectric materials through forming solid solutions and biaxial strain

Li, Juan; Zhang, Shuai; Wang, Boyi; Liu, Shichao; Luo, Yi; Lu, Guiwu; Zheng, Shuqi

doi:10.1039/c8ta07285j

Cited by 34 publications

(43 citation statements)

References 51 publications

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“…The room temperature thermal conductivity κ L for Mg 3 Sb 2 is 2.63 W/mK, obtained by averaging the in‐plane (2.67 W/mK) and out‐of‐plane (2.57 W/mK) values. Our κ L calculation for Mg 3 Sb 2 is consistent with some of the experimental measurements and other calculations . With the Mg octa replaced by Ca and Yb, the averaged κ L s can be further reduced by around 36% for Ca‐doped and 44% for Yb‐doped at 300 K, as shown in Figure a.…”

Section: Resultssupporting

confidence: 88%

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

Sun

Yang

et al. 2019

J Comput Chem

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Identifying strategies for beneficial band engineering is crucial for the optimization of thermoelectric (TE) materials. In this study, we demonstrate the beneficial effects of ionic dopants on n‐type Mg3Sb2. Using the band‐resolved projected crystal orbital Hamilton population, the covalent characters of the bonding between Mg atoms at different sites are observed. By partially substituting the Mg at the octahedral sites with more ionic dopants, such as Ca and Yb, the conduction band minimum (CBM) of Mg3Sb2 is altered to be more anisotropic with an enhanced band degeneracy of 7. The CBM density of states of doped Mg3Sb2 with these dopants is significantly enlarged by band engineering. The improved Seebeck coefficients and power factors, together with the reduced lattice thermal conductivities, imply that the partial introduction of more ionic dopants in Mg3Sb2 is a general solution for its n‐type TE performance. © 2019 Wiley Periodicals, Inc.

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Section: Resultssupporting

confidence: 88%

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

Sun

Yang

et al. 2019

J Comput Chem

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“…In addition, the narrowing of the band gap, accompanied by the increasing near-edge band widths, results in the decreasing band effective masses. This is confirmed in several reports 62,111 as well as the theoretical result 113 by BoltzTraP (Fig. 7b), which shows a clear decreasing trend in m c * of near-edge conduction bands from Mg 3 Sb 2 to Mg 3 SbBi to Mg 3 Bi 2 .…”

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

confidence: 88%

“…Inspired by the biaxial strain engineering 105 in p-type compounds, Li et al revealed that n-type electrical performance of Mg 3 Sb 2 can also be optimized by tuning ΔE KÀCB1 towards zero via the biaxial strain. 111 The iso-energy Fermi surface provides an intuitive shortcut to understand the multi-valley conduction bands in Mg 3 Sb 2 (see Fig. 5b-d).…”

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

confidence: 99%

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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“…We believe that this carrier conductive network forms a favorable carrier transport channel in real space. It was found that the disordering Bi/Sb at the anionic site is "far away" from the electronic transport channel, which explains the fact that the electrical conductivity of Mg 3+δ Sb 1.5 Bi 0.5 is very sensitive to the Mg vacancy but not to the disordering Bi/Sb [18,27,28]. Experimentally, excess Mg is necessary to suppress the formation of Mg vacancy and obtain stable n-type samples [19].…”

Section: Introductionmentioning

confidence: 99%

The Electronic Transport Channel Protection and Tuning in Real Space to Boost the Thermoelectric Performance of Mg _{3+
δ} Sb _{2-
y} Bi _y near Room Temperature

et al. 2020

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The optimization of thermoelectric materials involves the decoupling of the transport of electrons and phonons. In this work, an increased Mg1-Mg2 distance, together with the carrier conduction network protection, has been shown as an effective strategy to increase the weighted mobility (U=μm∗3/2) and hence thermoelectric power factor of Mg3+δSb2-yBiy family near room temperature. Mg3+δSb0.5Bi1.5 has a high carrier mobility of 247 cm2 V-1 s-1 and a record power factor of 3470 μW m-1 K-2 at room temperature. Considering both efficiency and power density, Mg3+δSb1.0Bi1.0 with a high average ZT of 1.13 and an average power factor of 3184 μW m-1 K-2 in the temperature range of 50-250°C would be a strong candidate to replace the conventional n-type thermoelectric material Bi2Te2.7Se0.3. The protection of the transport channel through Mg sublattice means alloying on Sb sublattice has little effect on electron while it significantly reduces phonon thermal conductivity, providing us an approach to decouple electron and phonon transport for better thermoelectric materials.

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Designing high-performance n-type Mg₃Sb₂-based thermoelectric materials through forming solid solutions and biaxial strain

Abstract: Thermoelectric performance can be largely enhanced by forming solid solutions and biaxial strain.

Cited by 34 publications

References 51 publications

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

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

The Electronic Transport Channel Protection and Tuning in Real Space to Boost the Thermoelectric Performance of Mg _{3+
δ} Sb _{2-
y} Bi _y near Room Temperature

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Designing high-performance n-type Mg3Sb2-based thermoelectric materials through forming solid solutions and biaxial strain

Abstract: Thermoelectric performance can be largely enhanced by forming solid solutions and biaxial strain.

Cited by 34 publications

References 51 publications

Achieving band convergence by tuning the bonding ionicity in n‐type Mg3Sb2

Achieving band convergence by tuning the bonding ionicity in n‐type Mg3Sb2

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

The Electronic Transport Channel Protection and Tuning in Real Space to Boost the Thermoelectric Performance of Mg 3+ δ Sb 2- y Bi y near Room Temperature

Contact Info

Product

Resources

About

Designing high-performance n-type Mg₃Sb₂-based thermoelectric materials through forming solid solutions and biaxial strain

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

Achieving band convergence by tuning the bonding ionicity in n‐type Mg₃Sb₂

The Electronic Transport Channel Protection and Tuning in Real Space to Boost the Thermoelectric Performance of Mg _{3+
δ} Sb _{2-
y} Bi _y near Room Temperature