New Opportunities in Existing Thermoelectric Materials: Grain Boundary Engineering in Pulverized p-Bi2Te3 System

2007 ◽  
Vol 1044 ◽  
Author(s):  
Jian He ◽  
Xiaohua Ji ◽  
Zhe Su ◽  
Nick Gothard ◽  
Justine Edwards ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Grain Boundary ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Grain Boundary Engineering ◽  
Nano Coating ◽  
Compatibility Factor ◽  
The Mean ◽  
Mean Time ◽  
Heterogeneous Layer

AbstractGrain boundary scattering provides an effective avenue to lower the thermal conductivity in polycrystalline thermoelectric materials, but it is hard to do this without simultaneously degrading the power factor that is the product of electrical conductivity and thermopower. An immediate question arises as to whether one can fabricate a thermoelectrically favorable grain boundary?In this paper we present a proof-of-principle grain boundary engineering study in the pulverized p-Bi2Te3 system. Utilizing the lately developed hydrothermal nano-coating technique, we fabricated an Alkali-metal(s)-containing surface layer with few tens of nm thick on the p-Bi2Te3 bulk reference grain, where it becomes part of the grain boundary upon hotpressing densification. The electrical resistivity, thermopower, thermal conductivity and Hall coefficient measurements constitute solid evidence that this heterogeneous layer helps decouple the otherwise inter-related resistivity, thermopower and thermal conductivity. To optimize the figure of merit ZT, we carefully varied the ratio between Na, K and Rb concentrations. It was found that the sample treated in the solution with Na/Rb =1:2 achieved a ZT comparable with that of the commercial ingot; in the mean time, the compatibility factor and robustness of device were considerably improved. In principle this technique can be applied to other existing polycrystalline thermoelectric materials as a new “tuning knob”.

Precision grain Boundary Engineering in commercial Bi2Te2.7Se0.3 thermoelectric materials towards high performance

2021 ◽  
Author(s):  
Shuankui Li ◽  
Zhongyuan Huang ◽  
Rui Wang ◽  
Chaoqi Wang ◽  
Wenguang Zhao ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Thermoelectric Materials ◽  
High Performance ◽  
General Strategy ◽  
Grain Boundary Engineering

The strong interrelation between electrical and thermo parameters have been regarded as one of the biggest bottlenecks to obtain high-performance thermoelectric materials. Therefore, to explore a general strategy to fully...

Investigation of Thermoelectric Materials: Substitution effect of Bi on the Ag1-xPb18MTe20 (M = Sb, Bi) (x = 0, 0.14, 0.3)

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mi-kyung Han ◽  
Huijun Kong ◽  
Ctirad Uher ◽  
Mercouri G Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Substitution Effect ◽  
Dimensionless Figure Of Merit ◽  
The Matrix ◽  
Mass Fluctuation

AbstractWe performed comparative investigations of the Ag1-xPb18MTe20 (M = Bi, Sb) (x = 0, 0.14, 0.3) system to better understand the roles of Sb and Bi on the thermoelectric properties. In both systems, the electrical conductivity nearly keeps the same values, while the Seebeck coefficient decreases dramatically in going from Sb to Bi. Compared to the lattice thermal conductivity of PbTe, that of AgPb18BiTe20 is substantially reduced. The lattice thermal conductivity of the Bi analog, however, is higher than that of AgPb18SbTe20 and this is attributed largely to the decrease in the degree of mass fluctuation between the nanostructures and the matrix (for the Bi analog). As a result the dimensionless figure of merit ZT of Ag1-xPb18MTe20 (M = Bi) is found to be smaller than that of Ag1-xPb18MTe20 (M = Sb).

scholarly journals Thermoelectric Materials for Textile Applications

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3154
Author(s):  
Kony Chatterjee ◽  
Tushar K. Ghosh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Inorganic Materials ◽  
Peltier Effect ◽  
Electronic Textiles ◽  
Heating And Cooling ◽  
Recent Attention

Since prehistoric times, textiles have served an important role–providing necessary protection and comfort. Recently, the rise of electronic textiles (e-textiles) as part of the larger efforts to develop smart textiles, has paved the way for enhancing textile functionalities including sensing, energy harvesting, and active heating and cooling. Recent attention has focused on the integration of thermoelectric (TE) functionalities into textiles—making fabrics capable of either converting body heating into electricity (Seebeck effect) or conversely using electricity to provide next-to-skin heating/cooling (Peltier effect). Various TE materials have been explored, classified broadly into (i) inorganic, (ii) organic, and (iii) hybrid organic-inorganic. TE figure-of-merit (ZT) is commonly used to correlate Seebeck coefficient, electrical and thermal conductivity. For textiles, it is important to think of appropriate materials not just in terms of ZT, but also whether they are flexible, conformable, and easily processable. Commercial TEs usually compromise rigid, sometimes toxic, inorganic materials such as bismuth and lead. For textiles, organic and hybrid TE materials are more appropriate. Carbon-based TE materials have been especially attractive since graphene and carbon nanotubes have excellent transport properties with easy modifications to create TE materials with high ZT and textile compatibility. This review focuses on flexible TE materials and their integration into textiles.

Enhancing the average thermoelectric figure of merit of elemental Te by suppressing grain boundary scattering

2020 ◽  
Vol 8 (17) ◽  
pp. 8455-8461 ◽  
Author(s):  
Yehao Wu ◽  
Feng Liu ◽  
Qi Zhang ◽  
Tiejun Zhu ◽  
Kaiyang Xia ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Grain Boundary ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Boundary Scattering ◽  
Thermoelectric Figure ◽  
Grain Boundary Scattering

Suppressed grain boundary scattering contributes to enhanced electrical conductivity and device zT in elemental Te based thermoelectric materials.

Thermoelectric Generators of Sequentially Deposited Si/Si+Ge Nano-layered Superlattices

2009 ◽  
Vol 1181 ◽  
Author(s):  
Cydale Smith ◽  
Marcus Pugh ◽  
Hervie Martin ◽  
Rufus Durel Hill ◽  
Brittany James ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
Absolute Temperature ◽  
Simulation Software ◽  
The Cross

AbstractEffective thermoelectric materials have a low thermal conductivity and a high electrical conductivity. The performance of the thermoelectric materials and devices is shown by a dimensionless figure of merit, ZT = S2sσ/ KTC, σ is the electrical conductivity T/KTC, where S is the Seebeck coefficient, T is the absolute temperature and KTC is the thermal conductivity. In this study we have prepared the thermoelectric generator device of Si/Si+Ge multi-layer superlattice films using the ion beam assisted deposition (IBAD). To determine the stoichiometry of the elements of Si and Ge in the grown multilayer films and the thickness of the grown multi-layer films Rutherford Backscattering Spectrometry (RBS) and RUMP simulation software package were used. The 5 MeV Si ion bombardments were performed to make quantum clusters in the multi-layer superlattice thin films to decrease the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and cross plane electrical conductivity.Keywords: Ion bombardment, thermoelectric properties, multi-nanolayers, Figure of merit.

Effect of FAPAS Process on the Thermoelectric Properties of β-FeSi2

2010 ◽  
Vol 650 ◽  
pp. 137-141
Author(s):  
Qing Sen Meng ◽  
Wen Hao Fan ◽  
L.Q. Wang ◽  
L.Z. Ding
Keyword(s):  
Thermal Conductivity ◽  
Grain Size ◽  
Phase Transformation ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Annealing Time ◽  
Figure Of Merit ◽  
Iron Disilicide ◽  
Temperature Range ◽  
Average Grain Size

Iron disilicide (-FeSi2, and -FeSi2+Cu0.1wt%) were prepared by a field-activated pressure assisted synthesis(FAPAS) method from elemental powders and the thermoelectric properties were investigated. The average grain size of these products is about 0.3m. The thermal conductivity of these materials is 3-4wm-1K-1in the temperature range 300-725K. These products’ figure of merit is 28.50×10-4 in the temperature range 330-450K. The additions of Cu promote the phase transformation of -Fe2Si5 + -FeSi → β-FeSi2 and shorten the annealing time. It is proved that FAPAS is a benign and rapid process for sintering of -FeSi2 thermoelectric materials.

Thermal Conductivity Reductions in Sige via Addition of Nanophase Particles

1994 ◽  
Vol 351 ◽  
Author(s):  
Nancy Scoville ◽  
Clara Bajger ◽  
Jon Rolfe ◽  
Jan Vandersande
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Erosion Process ◽  
Transport Models ◽  
Spark Erosion

ABSTRACTTransport models have predicted that the thermal conductivity of SiGe alloys could be appreciably reduced by incorporating a discrete 40Å particles with the SiGe grains. Such a thermal conductivity reduction would lead to substantial improvements in the figure-of-merit of thermoelectric materials. This paper reports on recent results on adding 40Å particles to SiGe via a spark erosion process. Thermal conductivity reductions consistent with the transport models have been achieved, however, the improvement in figure-of-merit has not been as large as predicted.

scholarly journals Achieving High Thermoelectric Performance in Rare-Earth Element-Free CaMg2Bi2 with High Carrier Mobility and Ultralow Lattice Thermal Conductivity

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Muchun Guo ◽  
Fengkai Guo ◽  
Jianbo Zhu ◽  
Li Yin ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Materials ◽  
Carrier Mobility ◽  
Lattice Thermal Conductivity ◽  
Low Cost ◽  
Thermoelectric Performance ◽  
Widespread Application ◽  
Compatibility Factor ◽  
High Carrier Mobility ◽  
High Carrier

CaMg2Bi2-based compounds, a kind of the representative compounds of Zintl phases, have uniquely inherent layered structure and hence are considered to be potential thermoelectric materials. Generally, alloying is a traditional and effective way to reduce the lattice thermal conductivity through the mass and strain field fluctuation between host and guest atoms. The cation sites have very few contributions to the band structure around the fermi level; thus, cation substitution may have negligible influence on the electric transport properties. What is more, widespread application of thermoelectric materials not only desires high ZT value but also calls for low-cost and environmentally benign constituent elements. Here, Ba substitution on cation site achieves a sharp reduction in lattice thermal conductivity through enhanced point defects scattering without the obvious sacrifice of high carrier mobility, and thus improves thermoelectric properties. Then, by combining further enhanced phonon scattering caused by isoelectronic substitution of Zn on the Mg site, an extraordinarily low lattice thermal conductivity of 0.51 W m-1 K-1 at 873 K is achieved in (Ca0.75Ba0.25)0.995Na0.005Mg1.95Zn0.05Bi1.98 alloy, approaching the amorphous limit. Such maintenance of high mobility and realization of ultralow lattice thermal conductivity synergistically result in broadly improvement of the quality factor β. Finally, a maximum ZT of 1.25 at 873 K and the corresponding ZTave up to 0.85 from 300 K to 873 K have been obtained for the same composition, meanwhile possessing temperature independent compatibility factor. To our knowledge, the current ZTave exceeds all the reported values in AMg2Bi2-based compounds so far. Furthermore, the low-cost and environment-friendly characteristic plus excellent thermoelectric performance also make the present Zintl phase CaMg2Bi2 more competitive in practical application.

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