Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Discovery of high-performance low-cost n-type Mg₃Sb₂-based thermoelectric materials with multi-valley conduction bands.

ABSTRACT: Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost n-type material, Te-doped Mg₃Sb_1.5Bi_0.5, that exhibits a very high figure of merit zT ranging from 0.56 to 1.65 at 300-725 K. Using combined theoretical prediction and experimental validation, we show that the high thermoelectric performance originates from the significantly enhanced power factor because of the multi-valley band behaviour dominated by a unique near-edge conduction band with a sixfold valley degeneracy. This makes Te-doped Mg₃Sb_1.5Bi_0.5 a promising candidate for the low- and intermediate-temperature thermoelectric applications.

SUBMITTER: Zhang J

PROVIDER: S-EPMC5227096 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Discovery of high-performance low-cost n-type Mg3Sb2-based thermoelectric materials with multi-valley conduction bands.

Zhang Jiawei J Song Lirong L Pedersen Steffen Hindborg SH Yin Hao H Hung Le Thanh LT Iversen Bo Brummerstedt BB

Nature communications 20170106

Widespread application of thermoelectric devices for waste heat recovery requires low-cost high-performance materials. The currently available n-type thermoelectric materials are limited either by their low efficiencies or by being based on expensive, scarce or toxic elements. Here we report a low-cost n-type material, Te-doped Mg3Sb1.5Bi0.5, that exhibits a very high figure of merit zT ranging from 0.56 to 1.65 at 300-725 K. Using combined theoretical prediction ...[more]

PMID: 28059069

Similar Datasets

Solid-State Janus Nanoprecipitation Enables Amorphous-Like Heat Conduction in Crystalline Mg3 Sb2 -Based Thermoelectric Materials.

Project description:Solid-state precipitation can be used to tailor material properties, ranging from ferromagnets and catalysts to mechanical strengthening and energy storage. Thermoelectric properties can be modified by precipitation to enhance phonon scattering while retaining charge-carrier transmission. Here, unconventional Janus-type nanoprecipitates are uncovered in Mg3 Sb1.5 Bi0.5 formed by side-by-side Bi- and Ge-rich appendages, in contrast to separate nanoprecipitate formation. These Janus nanoprecipitates result from local comelting of Bi and Ge during sintering, enabling an amorphous-like lattice thermal conductivity. A precipitate size effect on phonon scattering is observed due to the balance between alloy-disorder and nanoprecipitate scattering. The thermoelectric figure-of-merit ZT reaches 0.6 near room temperature and 1.6 at 773 K. The Janus nanoprecipitation can be introduced into other materials and may act as a general property-tailoring mechanism.

| S-EPMC9443448 | biostudies-literature

Revealing the Defect-Dominated Electron Scattering in Mg3Sb2-Based Thermoelectric Materials.

Project description:The thermoelectric parameters are essentially governed by electron and phonon transport. Since the carrier scattering mechanism plays a decisive role in electron transport, it is of great significance for the electrical properties of thermoelectric materials. As a typical example, the defect-dominated carrier scattering mechanism can significantly impact the room-temperature electron mobility of n-type Mg3Sb2-based materials. However, the origin of such a defect scattering mechanism is still controversial. Herein, the existence of the Mg vacancies and Mg interstitials has been identified by synchrotron powder X-ray diffraction. The relationship among the point defects, chemical compositions, and synthesis conditions in Mg3Sb2-based materials has been revealed. By further introducing the point defects without affecting the grain size via neutron irradiation, the thermally activated electrical conductivity can be reproduced. Our results demonstrate that the point defects scattering of electrons is important in the n-type Mg3Sb2-based materials.

| S-EPMC9620639 | biostudies-literature

Chemical bonding origin of the unexpected isotropic physical properties in thermoelectric Mg3Sb2 and related materials.

Project description:The Mg3Sb2 structure is currently being intensely scrutinized due to its outstanding thermoelectric properties. Usually, it is described as a layered Zintl phase with a clear distinction between covalent [Mg2Sb2]2- layers and ionic Mg2+ layers. Based on the quantitative chemical bonding analysis, we unravel instead that Mg3Sb2 exhibits a nearly isotropic three-dimensional bonding network with the interlayer and intralayer bonds being mostly ionic and surprisingly similar, which results in the nearly isotropic structural and thermal properties. The isotropic three-dimensional bonding network is found to be broadly applicable to many Mg-containing compounds with the CaAl2Si2-type structure. Intriguingly, a parameter based on the electron density can be used as an indicator measuring the anisotropy of lattice thermal conductivity in Mg3Sb2-related structures. This work extends our understanding of structure and properties based on chemical bonding analysis, and it will guide the search for and design of materials with tailored anisotropic properties.

| S-EPMC6226478 | biostudies-literature

Manipulation of ionized impurity scattering for achieving high thermoelectric performance in n-type Mg3Sb2-based materials.

Project description:Achieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type Mg3Sb2-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved. In this work, Fe, Co, Hf, and Ta are doped on the Mg site of Mg3.2Sb1.5Bi0.49Te0.01, where the ionized impurity scattering crosses over to mixed ionized impurity and acoustic phonon scattering. A significant improvement in Hall mobility from ∼16 to ∼81 cm2⋅V-1⋅s-1 is obtained, thus leading to a notably enhanced power factor of ∼13 μW⋅cm-1⋅K-2 from ∼5 μW⋅cm-1⋅K-2 A simultaneous reduction in thermal conductivity is also achieved. Collectively, a figure of merit (ZT) of ∼1.7 is obtained at 773 K in Mg3.1Co0.1Sb1.5Bi0.49Te0.01 The concept of manipulating the carrier scattering mechanism to improve the mobility should also be applicable to other material systems.

| S-EPMC5635921 | biostudies-literature

Large improvement in thermoelectric performance of pressure-tuned Mg3Sb2.

Project description:The Mg3Sb2-based Zintl compound is a promising candidate for a high-performance thermoelectric material with the advantage of the component elements being low cost, non-toxic and earth-abundant. Here, we investigate the influence of pressure on the electronic structure and p-type and n-type thermoelectric transport properties of Mg3Sb2 by using density functional theory and Boltzmann transport theory. The energy gaps first increase and then decrease with the increasing of pressure, and a peak value of the valley degeneracy of conduction band occurs at 4 GPa. Based on the calculated band structures, the zT (figure of merit) values of p-type Mg3Sb2 under pressure are significantly enhanced, which predominantly originates from the boosted PF (power factor) contributed by the increased carrier's relaxation time. When the carrier concentration reaches 1 × 1020 cm-3, the PF of p-type Mg3Sb2 at 4 GPa is increased by 35% relative to that of the compound at 0 GPa, thus leading to a considerably improved zT of ∼0.62 at 725 K. Under the same conditions, due to the increased density of states effective mass, the n-type Mg3Sb2 exhibits a highest PF of ∼19 μW cm-1 K-2 and a peak zT of 1.7. Therefore, pressure tuning is an effective method to improve the p-type and n-type thermoelectric transport performance of Mg3Sb2-based Zintl compounds. This work on Mg3Sb2 under pressure may provide a new mechanism for the experimenters towards the enhancement of the thermoelectric performance of materials.

| S-EPMC8978981 | biostudies-literature

First-principles study of thermoelectric properties of Mg2Si-Mg2Pb semiconductor materials.

Project description:Mg2XIV (XIV = Si, Ge, Sn) compounds are semiconductors and their solid solutions are believed to be promising mid-temperature thermoelectric materials. By contrast, Mg2Pb is a metal and few studies have been conducted to investigate the thermoelectric properties of Mg2Si-Mg2Pb solid solutions. Here, we present a theoretical study exploring whether Mg2Pb-Mg2Si solid solutions can be used as thermoelectric materials or not. We firstly constructed several Mg2Si1-x Pb x (0 ≤ x ≤ 1) structures and calculated their electronic structures. It is suggested that Mg2Si1-x Pb x are potential thermoelectric semiconductors in the range of 0 ≤ x ≤ 0.25. We then explicitly computed the electron relaxation time and both the electronic and lattice thermal conductivities of Mg2Si1-x Pb x (0 ≤ x ≤ 0.25) and studied the effect of Pb concentration on the Seebeck coefficient, electrical conductivity, thermal conductivity, and thermoelectric figure of merit (ZT). At low Pb concentration (x = 1/16), the ZT of the Mg2Si1-x Pb x solid solutions (up to 0.67 at 900 K) reaches a maximum and is much higher than that of Mg2Si.

| S-EPMC9080444 | biostudies-literature

High-efficiency and reliable same-parent thermoelectric modules using Mg3Sb2-based compounds.

Project description:Thermoelectric modules can convert waste heat directly into useful electricity, providing a clean and sustainable way to use fossil energy more efficiently. Mg3Sb2-based alloys have recently attracted considerable interest from the thermoelectric community due to their nontoxic nature, abundance of constituent elements and excellent mechanical and thermoelectric properties. However, robust modules based on Mg3Sb2 have progressed less rapidly. Here, we develop multiple-pair thermoelectric modules consisting of both n-type and p-type Mg3Sb2-based alloys. Thermoelectric legs based on the same parent fit into each other in terms of thermomechanical properties, facilitating module fabrication and ensuring low thermal stress. By adopting a suitable diffusion barrier layer and developing a new joining technique, an integrated all-Mg3Sb2-based module demonstrates a high efficiency of 7.5% at a temperature difference of 380 K, exceeding the state-of-the-art same-parent thermoelectric modules. Moreover, the efficiency remains stable during 150 thermal cycling shocks (∼225 h), demonstrating excellent module reliability.

| S-EPMC10174719 | biostudies-literature

Few-Layer PdSe2 Sheets: Promising Thermoelectric Materials Driven by High Valley Convergence.

Project description:Herein, we report a comprehensive study on the structural and electronic properties of bulk, monolayer, and multilayer PdSe2 sheets. First, we present a benchmark study on the structural properties of bulk PdSe2 by using 13 commonly used density functional theory (DFT) functionals. Unexpectedly, the most commonly used van der Waals (vdW)-correction methods, including DFT-D2, optB88, and vdW-DF2, fail to provide accurate predictions of lattice parameters compared to experimental data (relative error > 15%). On the other hand, the PBE-TS series functionals provide significantly improved prediction with a relative error of <2%. Unlike hexagonal two-dimensional materials like graphene, transition metal dichalcogenides, and h-BN, the conduction band minimum of monolayer PdSe2 is not located along the high symmetry lines in the first Brillouin zone; this highlights the importance of the structure-property relationship in the pentagonal lattice. Interestingly, high valley convergence is found in the conduction and valence bands in monolayer, bilayer, and trilayer PdSe2 sheets, suggesting promising application in thermoelectric cooling.

| S-EPMC6644379 | biostudies-literature

Thermoelectric Properties of Mg3(Bi,Sb)2 under Finite Temperatures and Pressures: A First-Principles Study.

Project description:Mg3Bi2-vSbv (0 ≤ v ≤ 2) is a class of promising thermoelectric materials that have a high thermoelectric performance around room temperatures, whereas their thermoelectric properties under pressures and temperatures are still illusive. In this study, we examined the influence of pressure, temperature, and carrier concentration on the thermoelectric properties of Mg3Bi2-vSbv using first-principle calculations accompanied with Boltzmann transport equations method. There is a decrease in the lattice thermal conductivity of Mg3Sb2 (i.e., v = 2) with increasing pressure. For a general Mg3Bi2-vSbv system, power factors are more effectively improved by n-type doping where electrons are the primary carriers over holes in n-type doping, and can be further enhanced by applied pressure. The figure of merit (zT) exhibits a positive correlation with temperature. A high zT value of 1.53 can be achieved by synergistically tuning the temperature, pressure, and carrier concentration in Mg3Sb2. This study offers valuable insights into the tailoring and optimization of the thermoelectric properties of Mg3Bi2-vSbv.

| S-EPMC10780500 | biostudies-literature

Wide-temperature-range thermoelectric n-type Mg3(Sb,Bi)2 with high average and peak zT values.

Project description:Mg3(Sb,Bi)2 is a promising thermoelectric material suited for electronic cooling, but there is still room to optimize its low-temperature performance. This work realizes >200% enhancement in room-temperature zT by incorporating metallic inclusions (Nb or Ta) into the Mg3(Sb,Bi)2-based matrix. The electrical conductivity is boosted in the range of 300-450 K, whereas the corresponding Seebeck coefficients remain unchanged, leading to an exceptionally high room-temperature power factor >30 μW cm-1 K-2; such an unusual effect originates mainly from the modified interfacial barriers. The reduced interfacial barriers are conducive to carrier transport at low and high temperatures. Furthermore, benefiting from the reduced lattice thermal conductivity, a record-high average zT > 1.5 and a maximum zT of 2.04 at 798 K are achieved, resulting in a high thermoelectric conversion efficiency of 15%. This work demonstrates an efficient nanocomposite strategy to enhance the wide-temperature-range thermoelectric performance of n-type Mg3(Sb,Bi)2, broadening their potential for practical applications.

| S-EPMC10654674 | biostudies-literature