Thermoelectric Properties of K2Bi8Se13−xSx Solid Solutions

2005 ◽  
Vol 886 ◽  
Author(s):  
Theodora Kyratsi ◽  
Sangeeta Lal ◽  
Tim Hogan ◽  
Mercouri G. Kanatzidis
Keyword(s):  
Thermal Conductivity ◽  
Solid Solution ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
The Other ◽  
Solid Solution Series ◽  
Type Character ◽  
Derivatives Of

AbstractDerivatives of β-K2Bi8Se13 are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. Up to now substitutions on the Bi and alkali metal sites have been studied in order to tune the thermoelectric properties. In this work, the thermoelectric properties of the sulfur-substituted K2Bi8Se13−xSx (0<x<13) are presented with respect to Seebeck coefficient, the electrical and thermal conductivity as a function of temperature. Seebeck coefficient measurements showed the n-type character of all members while electrical conductivity shows higher values compare to the other solid solution series of the same type. The lattice thermal conductivity is affected due to the Se/S disorder. The temperature dependence of the figure-of-merit ZT shows that these materials have potential for high temperatures applications with promising thermoelectric performance.

FEM Analysis on Thermoelectric Properties of Metal/TiO2–x Composites with Random Distribution of Metal Powder

2013 ◽  
Vol 750 ◽  
pp. 130-133
Author(s):  
Katsuhiro Sagara ◽  
Yun Lu ◽  
Dao Cheng Luan
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Figure Of Merit ◽  
Random Distribution ◽  
The Other ◽  
Dimensionless Figure Of Merit ◽  
Wide Range

Analysis model of finite element method with a random distribution for thermoelectric composites was built. Thermoelectric properties including electrical resistivity, Seebeck coefficient and thermal conductivity of M/TiO2–x (M = Cu, Ni, 304 stainless steel (304SS)) thermoelectric composites were investigated by the proposed model. Cu/TiO2–x composite showed a large decrease in electrical resistivity while 304SS/TiO2–x composite thermal conductivity was slightly increased. Calculated dimensionless figure-of-merit, ZT of Ni/TiO2–x composite was higher than those of TiO2–x and the other composites in a wide range of metal volume fractions because Ni has large absolute values of Seebeck coefficient, power factor and dimensionless figure-of-merit compared to the other two metals. It was found that power factor and dimensionless figure-of-merit of thermoelectric composites depended on the balance among electrical resistivity, thermal conductivity and Seebeck coefficient. The results revealed that it is important for M/TiO2–x composites to choose suitable addition metal with high power factor and dimensionless figure-of-merit.

Synthesis, Crystal Structure and Thermoelectric Properties of β-K2Bi8Se13 Solid Solutions

2003 ◽  
Vol 793 ◽  
Author(s):  
Theodora Kyratsi ◽  
Duck Young Chung ◽  
Jeff S. Dyck ◽  
Ctirad Uher ◽  
Sangeeta Lal ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid Solution ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Band Gaps ◽  
Solid Solution Series ◽  
Type K ◽  
Type Character ◽  
P Type

ABSTRACTSolid solution series of the type K2Bi8-xSbxSe13, K2-xRbxBi8Se13 as well as K2Bi8Se13-xSx were prepared and the distribution of the atoms (Bi/Sb, K/Rb and Se/S) on different crystallographic sites, the band gaps and their thermoelectric properties were studied. The distribution Se/S appears to be more uniform than the distribution of the Sb and Rb atoms in the β-K2Bi8Se13 structure that shows preference in specific sites in the lattice. Band gap is mainly affected by Sb and S substitution. Seebeck coefficient measurements showed n-type character for of all Se/S members. In the Bi/Sb series an enhancement of p-type character was observed. The thermoelectric performance as well as preliminary high temperature measurements suggest the potential of these materials for high temperature applications.

Thermoelectric Properties of Tl-X-Te (X=Pb, Sn, Ge) Systems

2005 ◽  
Vol 886 ◽  
Author(s):  
Atsuko Kosuga ◽  
Ken Kurosaki ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Solid State ◽  
Electrical Properties ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Dimensionless Figure Of Merit

ABSTRACTPolycrystalline-sintered samples of Tl2GeTe3, Tl4SnTe3, and Tl4PbTe3 were prepared by a solid-state reaction. Their thermoelectric properties were evaluated at temperatures ranging from room temperature to ca. 700 K by using the measured electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (κ). Despite their poor electrical properties, the dimensionless figure of merit ZT of all the compounds was relatively high, i.e., 0.74 at 673 K for Tl4SnTe3, 0.71 at 673 K for Tl4PbTe3, 0.29 at 473 K for Tl2GeTe3, due to the very low lattice thermal conductivity of the compounds.

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).

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 K2Bi8−xSbxSe13Solid Solutions and Se Doping

2001 ◽  
Vol 691 ◽  
Author(s):  
Theodora Kyratsi ◽  
Jeffrey S. Dyck ◽  
Wei Chen ◽  
Duck-Young Chung ◽  
Ctirad Uher ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Charge Transport ◽  
Transport Properties ◽  
Thermoelectric Properties ◽  
Solid Solutions ◽  
Figure Of Merit ◽  
Lattice Thermal Conductivity ◽  
Se Doping ◽  
Mass Fluctuation ◽  
Thermal Conductivities

ABSTRACTOur efforts to improve the thermoelectric properties of β-K2Bi8Se13, led to systematic studies of solid solutions of the type β-K2Bi8−xSbxSe13. The charge transport properties and thermal conductivities were studied for selected members of the series. Lattice thermal conductivity decreases due to the mass fluctuation generated in the lattice by the mixed occupation of Sb and Bi atoms. Se excess as a dopant was found to increase the figure-of merit of the solid solutions.

Thermoelectric Properties of n-type (Bi2Se3)x(Bi2Te3)1-x Crystals Prepared by Zone Melting

2008 ◽  
Vol 368-372 ◽  
pp. 547-549
Author(s):  
Jun Jiang ◽  
Ya Li Li ◽  
Gao Jie Xu ◽  
Ping Cui ◽  
Li Dong Chen
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Zone Melting ◽  
Chemical Compositions ◽  
Melting Method ◽  
Temperature Range

In the present study, n-type (Bi2Se3)x(Bi2Te3)1-x crystals with various chemical compositions were fabricated by the zone melting method. Thermoelectric properties, including Seebeck coefficient (α), electrical conductivity (σ) and thermal conductivity (κ), were measured in the temperature range of 300-500 K. The influence of the variations of Bi2Te3 and Bi2Se3 content on thermoelectric properties was studied. The increase of Bi2Se3 content (x) caused an increase in carrier concentration and thus an increase of σ and a decrease of α. The maximum figure of merit (ZT = α2σT/κ) of 0.87 was obtained at about 325 K for the composition of 93%Bi2Te3-7%Bi2Se3 with doping TeI4.

High-temperature thermoelectric properties of n-type BayNixCo4−xSb12

2001 ◽  
Vol 16 (12) ◽  
pp. 3343-3346 ◽  
Author(s):  
X. F. Tang ◽  
L. M. Zhang ◽  
R. Z. Yuan ◽  
L. D. Chen ◽  
T. Goto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Electron Concentration ◽  
Lattice Thermal Conductivity ◽  
Filling Fraction ◽  
Ni Content ◽  
Increasing Temperature

Effects of Ba filling fraction and Ni content on the thermoelectric properties of n-type BayNixCo4−xSb12 (x = 0−0.1, y = 0−0.4) were investigated at temperature range of 300 to 900 K. Thermal conductivity decreased with increasing Ba filling fraction and temperature. When y was fixed at 0.3, thermal conductivity decreased with increasing Ni content and reached a minimum value at about x = 0.05. Lattice thermal conductivity decreased with increasing Ni content, monotonously (y ≤ 0.1). Electron concentration and electrical conductivity increased with increasing Ba filling fraction and Ni content. Seebeck coefficient increased with increasing temperature and decreased with increasing Ba filling fraction and Ni content. The maximum ZT value of 1.25 was obtained at about 900 K for n-type Ba0.3Ni0.05Co3.95Sb12.

Thermoelectric Properties of CoSb3-based Skutterudite Compounds

2010 ◽  
Vol 1267 ◽  
Author(s):  
Adul Harnwunggmoung ◽  
Ken Kurosaki ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Room Temperature ◽  
Lattice Thermal Conductivity ◽  
Filling Ratio ◽  
Thermoelectric Figure Of Merit ◽  
Thermoelectric Figure ◽  
Alloy Scattering ◽  
Skutterudite Compound

AbstractCoSb3 is known as a skutterudite compound that could exhibit high thermoelectric figure of merit. However, the thermal conductivity of CoSb3 is relatively high. In order to enhance the thermoelectric performance of this compound, we tried to reduce the thermal conductivity of CoSb3 by substitution of Rh for Co and by Tl-filling into the voids. The polycrystalline samples of (Co,Rh)Sb3 and Tl-filled CoSb3 were prepared and the thermoelectric properties such as the Seebeck coefficient, electrical resistivity, and thermal conductivity were measured in the temperature range from room temperature to 750 K. The Rh substitution for Co reduced the lattice thermal conductivity, due to the alloy scattering effect. The minimum value of the lattice thermal conductivity was 4 Wm-1K-1 at 750 K obtained for (Co0.7Rh0.3)Sb3. Also the lattice thermal conductivity rapidly decreased with increasing the Tl-filling ratio. T10.25Co4Sb12 exhibited the best ZT values; the maximum ZT was 0.9 obtained at 600 K.

Synthesis and Thermoelectric Properties of Co4-XFeXSb12-YSnY Skutterudites

2011 ◽  
Vol 695 ◽  
pp. 65-68 ◽  
Author(s):  
Kwan Ho Park ◽  
Il Ho Kim
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Phonon Scattering ◽  
Charge Compensation ◽  
Fe Doping ◽  
Sn Doping ◽  
Double Doping

Co4-xFexSb12-ySny skutterudites were synthesized by mechanical alloying and hot pressing, and thermoelectric properties were examined. The carrier concentration increased by doping and thereby the electrical conductivity increased compared with intrinsic CoSb3. Every specimen had a positive Seebeck coefficient. Fe doping caused a decrease in the Seebeck coefficient but it could be enhanced by Fe/Sn double doping possibly due to charge compensation. The thermal conductivity was desirably very low and this originated from ionized impurity-phonon scattering. Thermoelectric properties were improved remarkably by Fe/Sn doping, and a maximum figure of merit, ZT = 0.5 was obtained at 723 K in the Co3FeSb11.2Sn0.8 specimen.

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