Intermediate-level doping strategy to simultaneously optimize power factor and phonon thermal conductivity for improving thermoelectric figure of merit

2020 ◽  
Vol 15 ◽  
pp. 100250 ◽  
Author(s):  
W. Ren ◽  
Q. Song ◽  
H. Zhu ◽  
J. Mao ◽  
L. You ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Intermediate Level ◽  
Thermoelectric Figure Of Merit ◽  
Phonon Thermal Conductivity ◽  
Thermoelectric Figure

Enhanced thermoelectric performance through carrier scattering at heterojunction potentials in BiSbTe based composites with Cu3SbSe4 nanoinclusions

2015 ◽  
Vol 3 (27) ◽  
pp. 7045-7052 ◽  
Author(s):  
Yuanyue Li ◽  
Di Li ◽  
Xiaoying Qin ◽  
Xiuhui Yang ◽  
Yongfei Liu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Thermoelectric Performance ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Carrier Scattering ◽  
Interface Scattering

Owing to enhanced power factor and reduced lattice thermal conductivity through interface scattering, a largest thermoelectric figure of merit ZT = 1.61 is achieved at 467 K for BiSbTe based composite with Cu3SbSe4 nanoinclusions.

scholarly journals Is LiI a Potential Dopant Candidate to Enhance the Thermoelectric Performance in Sb-Free GeTe Systems? A Prelusive Study

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 643 ◽  
Author(s):  
Bhuvanesh Srinivasan ◽  
David Berthebaud ◽  
Takao Mori
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Short Communication ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Plasma Sintering ◽  
Spark Plasma

As a workable substitute for toxic PbTe-based thermoelectrics, GeTe-based materials are emanating as reliable alternatives. To assess the suitability of LiI as a dopant in thermoelectric GeTe, a prelusive study of thermoelectric properties of GeTe1−xLiIx (x = 0–0.02) alloys processed by Spark Plasma Sintering (SPS) are presented in this short communication. A maximum thermoelectric figure of merit, zT ~ 1.2, was attained at 773 K for 2 mol% LiI-doped GeTe composition, thanks to the combined benefits of a noted reduction in the thermal conductivity and a marginally improved power factor. The scattering of heat carrying phonons due to the presumable formation of Li-induced “pseudo-vacancies” and nano-precipitates contributed to the conspicuous suppression of lattice thermal conductivity, and consequently boosted the zT of the Sb-free (GeTe)0.98(LiI)0.02 sample when compared to that of pristine GeTe and Sb-rich (GeTe)x(LiSbTe2)2 compounds that were reported earlier.

scholarly journals Effects of Ge Doping on the Charge Transport and Thermoelectric Properties of Permingeatites Cu3Sb1−yGeySe4

2021 ◽  
Vol 59 (6) ◽  
pp. 422-429
Author(s):  
Ji-Hee Pi ◽  
Go-Eun Lee, ◽  
Il-Ho Kim
Keyword(s):  
Thermal Conductivity ◽  
Charge Transport ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Lorenz Number ◽  
Degenerate Semiconductor ◽  
Thermoelectric Figure ◽  
Ge Doping

Permingeatites Cu3Sb1−yGeySe4 (0 ≤ y ≤ 0.14) were synthesized by mechanical alloying and hot pressing. The charge-transport parameters (Hall coefficient, carrier concentration, mobility, and Lorenz number) and thermoelectric properties (electrical conductivity, Seebeck coefficient, power factor, thermal conductivity, and figure of merit) were examined with respect to the Ge doping level. A single permingeatite phase with a tetragonal structure was obtained without subsequent heat treatment, but a small amount of the secondary phase Cu2GeSe3 was found for the specimens with y ≥ 0.08. All hot-pressed compacts exhibited a relative density of 97.5%–98.3%. The lattice constants of the a-axis and c-axis were decreased by the substitution of Ge at the Sb sites. As the Ge content increased, the carrier concentration increased from 5.2 × 1018 to 1.1 × 1020 cm−3, but the mobility decreased from 92 to 25 cm2·V−1·s−1. The Lorenz number of the undoped Cu3SbSe4 implied a non-degenerate semiconductor behavior, ranging from (1.57–1.56) × 10−8 V2·K−2 at 323–623 K. The thermoelectric figure of merit was 0.39 at 623 K, resulting from a power factor of 0.49 mW·m−1·K−2 and a thermal conductivity of 0.76 W·m−1·K−1. However, the Lorenz numbers of the Gedoped specimens indicated degenerate semiconductor characteristics, increasing to (1.63–1.94) × 10−8 V2·K−2 at 323–623 K. The highest thermoelectric figure of merit of 0.65 was at 623 K for Cu3Sb0.86Ge0.14Se4, resulting from the significantly improved power factor of 0.93 mW·m−1·K−2 and the thermal conductivity of 0.89W·m−1·K−1. As a result, the thermoelectric properties were remarkably enhanced by doping Ge into the Sb sites of the permingeatite.

Effects of Oxygen-Reduction on Thermoelectric Properties of Sr0.61Ba0.39Nb2O6 Ceramics

2014 ◽  
Vol 787 ◽  
pp. 210-214 ◽  
Author(s):  
Yi Li ◽  
Jian Liu ◽  
Chun Lei Wang ◽  
Wen Bin Su ◽  
Yuan Hu Zhu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Oxygen Reduction ◽  
Thermoelectric Power ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Thermoelectric Power Factor

The thermoelectric properties of Sr0.61Ba0.39Nb2O6 ceramics, reduced in various conditions, were investigated in the temperature range from 323K to 1073K. Both the electrical resistivity and the absolute Seebeck coefficient decreased with the deepening degree of oxygen-reduction. However, the decrease of the electrical resistivity had a major influence on the thermoelectric power factor. Therefore, the more heavily reduced sample can gain the higher value of thermoelectric power factor. It has been observed that the thermal conductivity increased with the deepening degree of oxygen-reduction, which indicates that the scattering of the oxygen vacancies produced by reduction does not play a dominant role in the thermal conduction. In spite of the increase of the thermal conductivity, the oxygen-reduction still promoted the thermoelectric figure of merit via the increase of the thermoelectric power factor. And the most heavily reduced Sr0.61Ba0.39Nb2O6 ceramic has the highest thermoelectric figure of merit (~0.18 at 1073 K) among all the samples.

scholarly journals Thermoelectric properties of Nb-doped Sr1−x (La0.5Na0.5) x TiO3 perovskites

2021 ◽  
Author(s):  
Makoto Tachibana ◽  
Ahmad Rifqi Muchtar ◽  
Takao Mori
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
High Power ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
High Power Factor ◽  
Nb Doping

Abstract We report the thermal conductivity (κ) of perovskite Sr1−x(La0.5Na0.5)xTiO3 (0 ≤ x ≤ 1) and the thermoelectric properties of Nb-doped samples for x = 0.1 and 0.2. The κ of the solid solution shows a distinct minimum near the cubic-tetragonal phase boundary at x = 0.2, where the value becomes close to the minimum theoretical κ. Nb doping to x = 0.2 retains the high power factor found in Nb-doped SrTiO3, but also raises the κ to result in a thermoelectric figure of merit of 0.24 at 773 K.

Thermoelectric Figure of Merit, ZT, of Single Crystal Pentatellurides (MTe5-XSex: M = Hf, Zr and x = 0, 0.25)

2000 ◽  
Vol 626 ◽  
Author(s):  
R. T. Littleton ◽  
Terry M. Tritt ◽  
B. Zawilski ◽  
J. W. Kolis ◽  
D. R. Ketchum ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Power Factor ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Large Power ◽  
Parent Materials ◽  
Se Substitution ◽  
Factor Α

ABSTRACTThe thermoelectric figure of merit, ZT = α2σT/λ, has been measured for pentatelluride single crystals of HfTe5, ZrTe5, as well as Se substituted pentatellurides. The parent materials, HfTe5 and ZrTe5, exhibit relatively large p- and n- type thermopower, |a| > 125 μV/K, and low resistivity, ρ ≤ 1 mΩ•cm. These values lead to a large power factor (α2σT) which is substantially increased with proper Se substitution on the Te sites. The thermal conductivity of these needle-like crystals has also been measured as a function of temperature from 10 K ≤ T ≤ 300 K. The room temperature figure of merit for these materials varies from ZT “0.1 for the parent materials to ZT ≈ 0.25 for Se substituted samples. These results as well as experimental procedures will be presented and discussed.

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.

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.

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