Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure

Chen, Xiaoxi; Wu, Haijun; Cui, Juan; Xiao, Yu; Zhang, Yang; He, Jiaqing; Chen, Yue; Cao, Jian; Cai, Wei; Pennycook, Stephen J.; Liu, Zihang; Zhao, Li‐Dong; Sui, Jiehe

doi:10.1016/j.nanoen.2018.07.059

Cited by 198 publications

(198 citation statements)

References 66 publications

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“…41,[45][46][47]49,50 and refs. [54][55][56][57][58][59][60]63,64,66,67,71 , respectively Although the Mg 3 Bi 2 alloying lowers the Seebeck coefficient due to the lighter conduction band mass and the weaker contribution from the secondary band minimum K, it is conducive to increasing the carrier mobility and weighted mobility as the conductivity effective mass m c * is decreased (see Fig. 7).…”

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

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“…The lattice thermal conductivity (κ latt ) can be obtained by subtracting the electronic thermal conductivity (κ e ) from the total thermal conductivity. The electronic thermal conductivity can be calculated by the Wiedemann–Franz relationship κ e = LσT , where L is the Lorenz number assumed to be L = 2.0 × 10 −8 W Ω K −2 , which is a typical value used to roughly calculate the lattice thermal conductivity for degenerate semiconductors 18,32,33. As shown in Figure 2d, the lattice thermal conductivity remains unchanged at ≈0.54 W m −1 K −1 with increasing La content up to x = 0.015 at higher temperature (≈600 K), indicating that La doping mostly influences the electronic thermal conductivity.…”

Section: Resultsmentioning

confidence: 99%

“…Acoustic phonon scattering dominates above 550 K, while a complex carrier scattering mechanism dominates below 550 K, which is possibly due to the inevitable Mg vacancies or other defects, as well as to the increased number of grain boundaries formed during the ball milling process,15,19,21 indicating that doping La at the Mg site may not suppress the formation of Mg vacancies like doping with transition metals (e.g., Co, Mn, Nb, etc.) does 16,18,20…”

Section: Resultsmentioning

confidence: 99%

“…This has inspired the further enhancement of electron concentration by extrinsic doping, typically by a chalcogen 9–12,15–17. Combined with the alloying of Mg 3 Bi 2 to decrease the lattice thermal conductivity, ZT values higher than 1.5 have been widely achieved 9,11,13,14,16,18–21. Furthermore, an enhanced room‐temperature ZT , which is close to that of the commercially available Bi 2 Te 3 , has been obtained in chalcogen‐doped Mg 3 Sb 2 ‐based materials by co‐doping with transition metals (e.g., Mn),17,18 tuning the mole ratio of Bi and Sb,17,22 and deliberately increasing the grain size,15,18,19,23 all of which result in increased carrier mobility.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg

Zhang

Chen

et al. 2020

Adv Elect Materials

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N‐type Mg3.2Sb1.5Bi0.5 materials are prepared by cation‐site doping with lanthanides (La, Ce). Both La‐ and Ce‐doped samples exhibit a higher doping limit and greater efficiency than those of chalcogen (Te, Se, S)‐doped n‐type Mg3.2Sb1.5Bi0.5 samples. High electron carrier concentration ≈9 × 1019 cm−3 is obtained in Mg3.18La0.02Sb1.5Bi0.5 and Mg3.185Ce0.015Sb1.5Bi0.5, which is close to the theoretical doping‐concentration limit and induces contributions from more electron bands. A higher electrical conductivity was thus obtained and is beneficial to the enhanced ZT values for lanthanide‐doped Mg3.2Sb1.5Bi0.5. The highest ZT value ≈1.6 is achieved in Mg3.19La0.01Sb1.5Bi0.5 at 693 K, along with a ZT ≈1.50 in Mg3.19Ce0.01Sb1.5Bi0.5 at 693 K, indicating that lanthanides provide a promising doping strategy for Mg3.2Sb1.5Bi0.5‐based materials.

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Mg₃₊_δSb_xBi₂₋_x Family: A Promising Substitute for the State‐of‐the‐Art n‐Type Thermoelectric Materials near Room Temperature

Shu

Zhou

Wang

et al. 2018

Adv Funct Materials

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The Bi2Te3−xSex family has constituted n‐type state‐of‐the‐art thermoelectric materials near room temperature (RT) for more than half a century, which dominates the active cooling and novel heat harvesting application near RT. However, the drawbacks of a brittle nature and Te‐content restricts the possibility for exploring potential applications. Here, it is shown that the Mg3+δSbxBi2−x family ((ZT)avg = 1.05) could be a promising substitute for the Bi2Te3−xSex family ((ZT)avg = 0.9–1.0) in the temperature range of 50–250 °C based on the comparable thermoelectric performance through a synergistic effect from the tunable bandgap using the alloy effect and the suppressible Mg‐vacancy formation using an interstitial Mn dopant. The former is to shift the optimal thermoelectric performance to near RT, and the latter is helpful to partially decouple the electrical transport and thermal transport in order to get an optimal RT power factor. The positive temperature dependence of the bandgap suggests this family is also a superior medium‐temperature thermoelectric material for the significantly suppressed bipolar effect. Furthermore, a two times higher mechanical toughness, compared with the Bi2Te3−xSex family, allows for a promising substitute for state‐of‐the‐art n‐type thermoelectric materials near RT.

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Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure

Cited by 198 publications

References 66 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

Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg

Mg₃₊_δSb_xBi₂₋_x Family: A Promising Substitute for the State‐of‐the‐Art n‐Type Thermoelectric Materials near Room Temperature

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Extraordinary thermoelectric performance in n-type manganese doped Mg3Sb2 Zintl: High band degeneracy, tuned carrier scattering mechanism and hierarchical microstructure

Cited by 198 publications

References 66 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

Enhanced Thermoelectric Performance in N‐Type Mg3.2Sb1.5Bi0.5 by La or Ce Doping into Mg

Mg3+δSbxBi2−x Family: A Promising Substitute for the State‐of‐the‐Art n‐Type Thermoelectric Materials near Room Temperature

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Enhanced Thermoelectric Performance in N‐Type Mg_3.2Sb_1.5Bi_0.5 by La or Ce Doping into Mg

Mg₃₊_δSb_xBi₂₋_x Family: A Promising Substitute for the State‐of‐the‐Art n‐Type Thermoelectric Materials near Room Temperature