Preparation and evaluation of the n-type PbTe based material properties for thermoelectric generators

2013 ◽  
Vol 1490 ◽  
pp. 179-184
Author(s):  
Tse-Hsiao Li ◽  
Jenn-Dong Hwang ◽  
Hsu-Shen Chu ◽  
Chun-Mu Chen ◽  
Chia-Chan Hsu ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Waste Heat ◽  
Lead Telluride ◽  
Absolute Temperature ◽  
Factors Affecting ◽  
High Figure ◽  
General Physical

ABSTRACTOwing to energy conservation of waste heat, Lead telluride, PbTe, based materials have promising good thermoelectric properties around a range of middle temperature (Fig. 1, from 300 to 600°C), due to their high melting point, fine chemical stability, and the high figure of merit Z. The general physical properties and factors affecting the figure of merit have been reviewed. This research is focused on the n-type of PbTe materials and collocated with analysis of densities, hardness, elastic modulus, and thermoelectric properties thermoelectric figure of merit ZT=GS2T/κ (where G is electrical conductivity, S is Seebeck coefficient , T is absolute temperature, and κ is thermal conductivity). Room temperature hardness and Young’s modulus are measured by nano-indentation. In this study, the hot-press compacts under the pressure of 4 ton/cm2 can reach the maximum density about 8.2 g/cm3, and hardness and elastic modulus are 0.6 GPa and 70 GPa, respectively. The figure of merit value (ZT) of PbTe in low temperature (around 340°C) was found about 1 with carrier concentration above 1019 cm−3. These results also indicate that the powder metallurgy parameters provide potentialities for further increase of the high efficiency of energy conversion in PbTe materials.

Heat Transport in Superlattices and Nanocomposites for Thermoelectric Applications

2006 ◽  
Vol 46 ◽  
pp. 104-110 ◽  
Author(s):  
Gang Chen
Keyword(s):  
Thermal Conductivity ◽  
Figure Of Merit ◽  
Large Scale ◽  
Energy Transport ◽  
High Efficiency ◽  
Waste Heat ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure

Energy transport in nanostructures differs significantly from macrostructures because of classical and quantum size effects on energy carriers. Experimental results show that the thermal conductivity values of nanostructures such as superlattices are significantly lower than that of their bulk constituent materials. The reduction in thermal conductivity led to a large increase in the thermoelectric figure of merit in several superlattice systems. Materials with a large thermoelectric figure of merit can be used to develop efficient solid-state devices that convert waste heat into electricity. Superlattices grown by thin-film deposition techniques, however, are not suitable for large scale applications. Nanocomposites represent one approach that can lead to high thermoelectric figure merit. This paper reviews the current understanding of thermal conductivity reduction mechanisms in superlattices and presents theoretical studies on thermoelectric properties in semiconducting nanocomposites, aiming at developing high efficiency thermoelectric energy conversion materials.

scholarly journals Quantum interference and structure-dependent orbital-filling effects on the thermoelectric properties of quantum dot molecules

2015 ◽  
Vol 17 (29) ◽  
pp. 19386-19393 ◽  
Author(s):  
Chih-Chieh Chen ◽  
David M. T. Kuo ◽  
Yia-Chung Chang
Keyword(s):  
Quantum Dot ◽  
Thermoelectric Properties ◽  
Anderson Model ◽  
Coulomb Blockade ◽  
Quantum Interference ◽  
Figure Of Merit ◽  
Quantum Dot Molecules ◽  
High Figure ◽  
Full Solution ◽  
Coulomb Blockade Regime

The quantum interference and orbital filling effects on the thermoelectric (TE) properties of quantum dot (QD) molecules with high figure of merit are illustrated via the full solution to the Hubbard–Anderson model in the Coulomb blockade regime.

scholarly journals Enhancement in thermoelectric properties due to Ag nanoparticles incorporated in Bi2Te3 matrix

2019 ◽  
Vol 10 ◽  
pp. 634-643 ◽  
Author(s):  
Srashti Gupta ◽  
Dinesh Chandra Agarwal ◽  
Bathula Sivaiah ◽  
Sankarakumar Amrithpandian ◽  
Kandasami Asokan ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Transmission Electron ◽  
High Power Factor ◽  
Different Temperatures ◽  
High Figure ◽  
Filtering Effect ◽  
P Type ◽  
20 Nm

The present study aims to see the enhancement in thermoelectric properties of bismuth telluride (Bi2Te3) annealed at different temperatures (573 and 773 K) through silver (Ag) nano-inclusions (0, 2, 5, 10, 15 and 20 wt %). Transmission electron microscopy (TEM) images of Ag incorporated in Bi2Te3 annealed at 573 K shows tubular, pentagonal, trigonal, circular and hexagonal nanoparticles with sizes of 6–25 nm (for 5 wt % Ag ) and 7–30 nm (for 20 wt % Ag). Ag incorporated in Bi2Te3 annealed at 773 K shows mainly hexagonally shaped structures with particle sizes of 2–20 nm and 40–80 nm (for 5 wt % Ag) and 10–60 nm (for 20 wt % Ag). Interestingly, the samples annealed at 573 K show the highest Seebeck coefficient (S, also called thermopower) at room temperature (p-type behavior) for 5% Ag which is increased ca. five-fold in comparison to Ag-free Bi2Te3, whereas for samples with the same content (5% Ag) annealed at 773 K the increment in thermopower is only about three-fold with a 6.9-fold enhancement of the power factor (S 2σ). The effect of size and shape of the nanoparticles on thermoelectric properties can be understood on the basis of a carrier-filtering effect that results in an increase in thermopower along with a control over the reduction in electrical conductivity to maintain a high power factor yielding a high figure of merit.

Effects of High Figure of Merit Bi2Te3 Based Superlattices on Thermoelectric Power Generation

2008 ◽  
Author(s):  
Christopher A. Howells ◽  
Cynthia Watkins ◽  
Rama Venkatasubramanian
Keyword(s):  
Power Generation ◽  
Figure Of Merit ◽  
Thermoelectric Module ◽  
Internal Resistance ◽  
Absolute Temperature ◽  
Electrical Measurements ◽  
Standard Pressure ◽  
High Figure ◽  
Resistive Loads ◽  
P Type

We have investigated the power generation characteristics of thermoelectric devices made from high Figure of Merit p-type Bi2Te3/Sb2Te3 and n-type Bi2Te3/Bi2Te2.7Se0.3 superlattice materials. The Figure of Merit, ZT (where Z is a measure of the material’s thermoelectric properties and T is the absolute temperature) of the p-type and n-type superlattices were each measured at 300K and found to be 2.4 and 1.2 respectively [1]. Sixteen p-n couples were developed using these superlattice materials and they were configured into a 4×4 thermoelectric module. The electrical measurements (Current, Voltage, and Power) of the 4×4 superlattice thermoelectric modules under various resistive loads and temperature differentials in a standard pressure environment are presented and from these, we have determined the peak power and internal resistance of the module. We also discuss other opportunities to further investigate this device as well as its suitability for power applications.

scholarly journals n-type thermoelectric material Mg2Sn0.75Ge0.25 for high power generation

2015 ◽  
Vol 112 (11) ◽  
pp. 3269-3274 ◽  
Author(s):  
Weishu Liu ◽  
Hee Seok Kim ◽  
Shuo Chen ◽  
Qing Jie ◽  
Bing Lv ◽  
...  
Keyword(s):  
Power Generation ◽  
Output Power ◽  
High Power ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Waste Heat ◽  
Flow Equation ◽  
Thermoelectric Figure ◽  
One Dimensional ◽  
High Power Factor

Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg2Sn-based material, Mg2Sn0.75Ge0.25, is a good example to meet the dual requirements in efficiency and output power. It was found that Mg2Sn0.75Ge0.25 has an average ZT of 0.9 and PF of 52 μW⋅cm−1⋅K−2 over the temperature range of 25–450 °C, a peak ZT of 1.4 at 450 °C, and peak PF of 55 μW⋅cm−1⋅K−2 at 350 °C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with Th = 400 °C and Tc = 50 °C to be of 10.5% and 6.6 W⋅cm−2 under a temperature gradient of 150 °C⋅mm−1, respectively.

scholarly journals Realizing a 14% single-leg thermoelectric efficiency in GeTe alloys

2021 ◽  
Vol 7 (19) ◽  
pp. eabf2738
Author(s):  
Zhonglin Bu ◽  
Xinyue Zhang ◽  
Bing Shan ◽  
Jing Tang ◽  
Hongxia Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Phonon Scattering ◽  
Waste Heat ◽  
Chemical Diffusion ◽  
Thermoelectric Device ◽  
Thermoelectric Efficiency ◽  
Good Service ◽  
Thermoelectric Figure

GeTe alloys have recently attracted wide attention as efficient thermoelectrics. In this work, a single-leg thermoelectric device with a conversion efficiency as high as 14% under a temperature gradient of 440 K was fabricated on the basis of GeTe-Cu2Te-PbSe alloys, which show a peak thermoelectric figure of merit (zT) > 2.5 and an average zT of 1.8 within working temperatures. The high performance of the material is electronically attributed to the carrier concentration optimization and thermally due to the strengthened phonon scattering, the effects of which all originate from the defects in the alloys. A design of Ag/SnTe/GeTe contact successfully enables both a prevention of chemical diffusion and an interfacial contact resistivity of 8 microhm·cm2 for the realization of highly efficient devices with a good service stability/durability. Not only the material’s high performance but also the device’s high efficiency demonstrated the extraordinariness of GeTe alloys for efficient thermoelectric waste-heat recovery.

scholarly journals The efficiency of short sintering time on thermoelectric properties of delafossite CuCr0:85Mg0:15O2 ceramics

2021 ◽  
Vol 24 (2) ◽  
pp. first
Author(s):  
Dung Van Hoang ◽  
Truong Huu Nguyen ◽  
Anh Tuan Thanh Pham ◽  
Thu Bao Nguyen Le ◽  
Vinh Cao Tran ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Fossil Fuel ◽  
Waste Heat ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Sintering Time ◽  
Dimensionless Figure Of Merit ◽  
The Cost

Introduction: Harvesting the waste heat emitted from the activities of humanity based on thermoelectric devices is an appropriate way to reduce the overconsumption of fossil fuel nowadays. Methods: In this work, CuCr0:85Mg0:15O2 compounds prepared by conventional solid-state reaction method were investigated to find out that the short sintering time is enough for thermoelectric applications, directly low the cost of the devices. Results and Conclusion: We find out that there is a significant change in the crystal structure, the chemical state, and thermoelectric properties along with the increase of the sintering time, but eventually, the dimensionless figure of merit ZT is almost constant regardless of the long or short sintering time which means that the increase of electrical conductivity will compromise the increase of thermal conductivity. The highest ZT value is 0.03 measured at 500 oC for both samples prepared at the sintering time of 3 and 12 hours.

High figure of merit and thermoelectric properties of Bi-doped Mg2Si0.4Sn0.6 solid solutions

2013 ◽  
Vol 203 ◽  
pp. 333-339 ◽  
Author(s):  
Wei Liu ◽  
Qiang Zhang ◽  
Kang Yin ◽  
Hang Chi ◽  
Xiaoyuan Zhou ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Solid Solutions ◽  
Figure Of Merit ◽  
High Figure

Research on springback characteristic in flexible multi-points 3D stretch-bending process

2021 ◽  
pp. 095440542110284
Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Vertical Direction ◽  
Factors Affecting ◽  
Stretch Bending ◽  
Element Simulation ◽  
Bending Process ◽  
Bending Radius ◽  
Aluminum Profiles ◽  
Bending Sequence

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.

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