scholarly journals NANOCOMPOSITES TO ENHANCE ZT IN THERMOELECTRICS

2007 ◽  
Vol 1044 ◽  
Author(s):  
Mildred Dresselhaus ◽  
Gang Chen ◽  
Zhifeng Ren ◽  
Jean-Pierre Fleurial ◽  
Pawan Gogna ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
High Temperature ◽  
Figure Of Merit ◽  
Scale Up ◽  
Simultaneous Increase ◽  
Thermoelectric Figure Of Merit ◽  
Materials Synthesis ◽  
Thermoelectric Figure ◽  
General Terms

AbstractThe concept of using “self-assembled” and “force-engineered” nanostructures to enhance the thermoelectric figure of merit relative to bulk homogeneous and composite materials is presented in general terms. Specific application is made to the Si-Ge system for use in power generation at high temperature. The scientific advantages of the nanocomposite approach for the simultaneous increase in the power factor and decrease of the thermal conductivity are emphasized along with the practical advantages of having bulk samples for property measurements and a straightforward path to scale-up materials synthesis and integration of nanostructured materials into thermoelectric cooling and power generation devices.

Thermoelectric Properties of Semiconducting Intermetallic Compounds: FeGa3and RuGa3

2003 ◽  
Vol 793 ◽  
Author(s):  
Y. Amagai ◽  
A. Yamamoto ◽  
C. H. Lee ◽  
H. Takazawa ◽  
T. Noguchi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Transport Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Seebeck Coefficient

ABSTRACTWe report transport properties of polycrystalline TMGa3(TM = Fe and Ru) compounds in the temperature range 313K<T<973K. These compounds exhibit semiconductorlike behavior with relatively high Seebeck coefficient, electrical resistivity, and Hall carrier concentrations at room temperature in the range of 1017- 1018cm−3. Seebeck coefficient measurements reveal that FeGa3isn-type material, while the Seebeck coefficient of RuGa3changes signs rapidly from large positive values to large negative values around 450K. The thermal conductivity of these compounds is estimated to be 3.5Wm−1K−1at room temperature and decreased to 2.5Wm−1K−1for FeGa3and 2.0Wm−1K−1for RuGa3at high temperature. The resulting thermoelectric figure of merit,ZT, at 945K for RuGa3reaches 0.18.

scholarly journals N-Type Bismuth Telluride Nanocomposite Materials Optimization for Thermoelectric Generators in Wearable Applications

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1529 ◽  
Author(s):  
Amin Nozariasbmarz ◽  
Jerzy S. Krasinski ◽  
Daryoosh Vashaee
Keyword(s):  
Thermal Conductivity ◽  
Power Generation ◽  
Seebeck Coefficient ◽  
Figure Of Merit ◽  
Microwave Cavity ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Efficient Operation ◽  
High Seebeck Coefficient ◽  
Body Heat

Thermoelectric materials could play a crucial role in the future of wearable electronic devices. They can continuously generate electricity from body heat. For efficient operation in wearable systems, in addition to a high thermoelectric figure of merit, zT, the thermoelectric material must have low thermal conductivity and a high Seebeck coefficient. In this study, we successfully synthesized high-performance nanocomposites of n-type Bi2Te2.7Se0.3, optimized especially for body heat harvesting and power generation applications. Different techniques such as dopant optimization, glass inclusion, microwave radiation in a single mode microwave cavity, and sintering conditions were used to optimize the temperature-dependent thermoelectric properties of Bi2Te2.7Se0.3. The effects of these techniques were studied and compared with each other. A room temperature thermal conductivity as low as 0.65 W/mK and high Seebeck coefficient of −297 μV/K were obtained for a wearable application, while maintaining a high thermoelectric figure of merit, zT, of 0.87 and an average zT of 0.82 over the entire temperature range of 25 °C to 225 °C, which makes the material appropriate for a variety of power generation applications.

Thermoelectric properties of (Bi,Pb)–Sr–Co–O oxide

2000 ◽  
Vol 15 (2) ◽  
pp. 382-386 ◽  
Author(s):  
Woosuck Shin ◽  
Norimitsu Murayama
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Single Crystal ◽  
Figure Of Merit ◽  
Polycrystalline Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Sinter Forging ◽  
Thermoelectric Application

Electrical conductivity and thermopower of Bi2Sr3Co2Ox sintered bodies were first investigated in the temperature range 440–1060 K in air for high-temperature thermoelectric application. The samples fabricated by the sinter-forging method increased their bulk densities and electrical conductivity. The value of thermopower and the temperature dependence of electrical conductivity of the sinter-forged samples were close to that of the single crystal. Evaluating the thermal conductivity of the polycrystalline sample, we calculated a thermoelectric figure of merit Z to be 0.107 × 10−3 K−1 at 1060 K.

Thermoelectric Properties of BaxCo4Sb12 Prepared by High Pressure and High Temperature

2011 ◽  
Vol 415-417 ◽  
pp. 1615-1619
Author(s):  
Bing Ke Qin ◽  
Yong Hua Ji ◽  
Zhi Li ◽  
Xiao Peng Jia
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Filled Skutterudite

Polycrystalline filled Skutterudite compounds BaxCo4Sb12(0-x-0.5) are synthesized by high pressure and high temperature （HPHT） technique. The thermal conductivity for CoSb3is depressed significantly by Ba-filling combined HPHT technique. The value of 1.25 Wm-1K-1for Ba0.372Co4Sb12is obtained at 633K. The dimensionless thermoelectric figure of merit ZT, increases with temperature increasing and reaches a maximal value of 1.01 at 663 K.

scholarly journals Thermoelectric properties of Ni0.15Co3.85Sb12 and Fe0.2Ni0.15Co3.65Sb12 skutterudites prepared by HPHT method

2017 ◽  
Vol 35 (3) ◽  
pp. 496-500 ◽  
Author(s):  
Lingjiao Kong ◽  
Hongan Ma ◽  
Yuewen Zhang ◽  
Xin Guo ◽  
Bing Sun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
High Pressure ◽  
High Temperature ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Synthesis Time

AbstractN-type polycrystalline skutterudite compounds Ni0.15Co3.85Sb12 and Fe0.2Ni0.15Co3.65Sb12 with the bcc crystal structure were synthesized by high pressure and high temperature (HPHT) method. The synthesis time was sharply reduced to approximately half an hour. Typical microstructures connected with lattice deformations and dislocations were incorporated in the samples of Ni0.15Co3.85Sb12 and Fe0.2Ni0.15Co3.65Sb12 after HPHT. Electrical and thermal transport properties were meticulously researched in the temperature range of 300 K to 700 K. The Fe0.2Ni0.15Co3.65Sb12 sample shows a lower thermal conductivity than that of Ni0.15Co3.85Sb12. The dimensionless thermoelectric figure-of-merit (zT) reaches the maximal values of 0.52 and 0.35 at 600 K and 700 K respectively, for Ni0.15Co3.85Sb12 and Fe0.2Ni0.15Co3.65Sb12 samples synthesized at 1 GPa.

scholarly journals The use of materials based on Si3N4 in the composition of composites for the design of high-temperature thermoelectric generators

2020 ◽  
pp. 7-14
Author(s):  
V.V. Tsygoda ◽  
V.Ya. Petrovskiy
Keyword(s):  
Thermal Conductivity ◽  
High Temperature ◽  
Figure Of Merit ◽  
Negative Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Generators ◽  
Thermoelectric Figure ◽  
Coefficient Of Thermal Conductivity ◽  
Materials Used ◽  
First Time

The possibility of reducing the thermal conductivity of silicon nitride as a basis of high-temperature electrical converters was investigated in the thesis. Also, the values of thermoelectric figure of merit and efficiency of thermoelectric current generator for the case of refractory oxygen-free composites were simulated. During the study, the dependence between the m coefficient, which determines the maximum possible efficiency of the thermoelectric generator and the ZT thermoelectric figure of merit, was determined. It was shown that the coefficient of thermal conductivity of the studied materials ranges from 1,2 to 4·106 m2/s and is characterized by a negative temperature coefficient over the entire temperature range. It was found that the thermal conductivity of Si3N4-based materials varies from 2,1 to 5,1 W/(m·K) depending on the type of sintering activator. The use of Al2O3 as an activator makes it possible to obtain a 25% lower thermal conductivity value comparing to materials with the addition of MgO. For the first time, it was proved that currently it is not possible to achieve an efficiency of 0,5hT in Si3N4-based materials used as a composite basis for high-temperature thermoelectric generators development.

Influence of multi-sintering on the thermoelectric properties of Bi2Sr2Co2Oy ceramics

2019 ◽  
Vol 34 (02) ◽  
pp. 2050019 ◽  
Author(s):  
Y. Zhang ◽  
M. M. Fan ◽  
C. C. Ruan ◽  
Y. W. Zhang ◽  
X.-J. Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Sintered Sample ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
The Third ◽  
Ceramic Samples ◽  
Optimum Formula

[Formula: see text] ceramic samples have a structure similar to phonon glass electronic crystals, and their thermoelectric properties can be effectively adjusted through repeated grinding and sintering. The results show that multi-sintering can make their grain refined and increase their grain boundary, which will effectively increase density and phonon scattering. Finally, multi-sintering can reduce the resistivity and thermal conductivity, thus obviously improve thermoelectric figure of merit [Formula: see text] of [Formula: see text]. The optimum [Formula: see text] value of 0.26 is achieved at 923 K by the third sintered sample.

Effects of Ce filling fraction and Fe content on the thermoelectric properties of Co-rich CeyFexCo4−xSb12

2001 ◽  
Vol 16 (3) ◽  
pp. 837-843 ◽  
Author(s):  
Xinfeng Tang ◽  
Lidong Chen ◽  
Takashi Goto ◽  
Toshio Hirai
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Hole Concentration ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Filling Fraction ◽  
Fe Content

Single-phase filled skutterudite compounds, CeyFexCo4−xSb12 (x = 0 to 3.0, y = 0 to 0.74), were synthesized by a melting method. The effects of Fe content and Ce filling fraction on the thermoelectric properties of CeyFexCo4−xSb12 were investigated. The lattice thermal conductivity of Ce-saturated CeyFexCo4−xSb12, y being at the maximum corresponding to x, decreased with increasing Fe content (x) and reached its minimum at about x = 1.5. When x was 1.5, lattice thermal conductivity decreased with increasing Ce filling fraction till y = 0.3 and then began to increase after reaching the minimum at y = 0.3. Hole concentration and electrical conductivity of Cey Fe1.5Co2.5Sb12 decreased with increasing Ce filling fraction. The Seebeck coefficient increased with increasing Ce filling fraction. The greatest dimensionless thermoelectric figure of merit T value of 1.1 was obtained at 750 K for the composition of Ce0.28Fe1.52Co2.48Sb12.

scholarly journals Термоэлектрические свойства нанокомпозитного Bi-=SUB=-0.45-=/SUB=-Sb-=SUB=-1.55-=/SUB=-Te-=SUB=-2.985-=/SUB=- с микрочастицами SiO-=SUB=-2-=/SUB=-

2019 ◽  
Vol 53 (6) ◽  
pp. 751
Author(s):  
А.А. Шабалдин ◽  
П.П. Константинов ◽  
Д.А. Курдюков ◽  
Л.Н. Лукьянова ◽  
А.Ю. Самунин ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Wide Temperature Range ◽  
Figure Of Merit ◽  
Nanostructured Material ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Efficiency ◽  
Thermoelectric Figure ◽  
P Type

AbstractNanocomposite thermoelectrics based on Bi_0.45Sb_1.55Te_2.985 solid solution of p -type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the addition of SiO_2 microparticles. Investigations of the thermoelectric properties show that the thermoelectric power of the nanocomposites increases in a wide temperature range of 80–420 K, while the thermal conductivity considerably decreases at 80–320 K, which, despite a decrease in the electrical conductivity, leads to an increase in the thermoelectric efficiency in the nanostructured material without the SiO_2 addition by almost 50% (at 300 K). When adding SiO_2, the efficiency decreases. The initial thermoelectric fabricated without nanostructuring, in which the maximal thermoelectric figure of merit ZT = 1 at 390 K, is most efficient at temperatures above 350 K.

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