scholarly journals Thermoelectric Properties of Sr1-3x/2Lax/2Smx/2TiO3-δ (0.05 ≤ x ≤ 0.30) Ceramics

2021 ◽  
Author(s):  
Adindu C. Iyasara
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Ceramic Powders ◽  
Thermoelectric Figure ◽  
Seebeck Coefficients ◽  
Reducing Gas ◽  
Maximum Value ◽  
Heat Treated ◽  
Electrical Conductivities ◽  
Sintering Processes

Abstract Influence of strongly reducing processing atmosphere on Sr-vacancy Sr1-3x/2Lax/2Smx/2TiO3-δ (x = 0.05, 0.10, 0.15, 0.20, 0.30) ceramics was investigated. The ceramic powders were prepared by the solid-state reaction (SSR) method, and heat treated in 5 % H2/N2 reducing gas at 1573 K for 6 h and 1773 K for 8 h for calcination and sintering processes, respectively. Thermoelectric properties of Sr1-3x/2Lax/2Smx/2TiO3-δ ceramics were evaluated from 573 to 973 K. Their electrical conductivities increased with carrier concentration and also decreased with temperature, indicating metallic behaviour. The Seebeck coefficients showed n-type behaviour and increased with temperature. Additionally, the total thermal conductivities exhibited low values, with a minimum value, 2.67 W/m. K for x = 0.20 ceramics at 973 K. A maximum thermoelectric figure of merit, ZT = 0.30 at 973 K was reached for Sr0.7La0.1Sm0.1TiO3-δ ceramics, which is 20 % higher than the maximum value reported previously for La-Sm electron doped SrTiO3 ceramics.

Thermoelectric properties of Cu2Se/xNi0.85Se hot-pressed from hydrothermal synthesis nanopowders

2017 ◽  
Vol 31 (09) ◽  
pp. 1750093 ◽  
Author(s):  
Feng Gao ◽  
Xiaohan Du ◽  
Fang Wu ◽  
Xinjian Li ◽  
Xing Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Hydrothermal Synthesis ◽  
Hydrothermal Method ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Secondary Phase ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Bulk Alloys

The [Formula: see text] ([Formula: see text] = 0, 0.025, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, 0.4 and 0.5) nanopowders were synthesized by the hydrothermal method and then were hot-pressed into bulk alloys. The effects of [Formula: see text] secondary phase on the thermoelectric (TE) properties of [Formula: see text] were investigated. For [Formula: see text] and [Formula: see text], both their electrical resistivity and Seebeck coefficients increase. While for [Formula: see text], they decrease instead. The samples for [Formula: see text] have lower thermal conductivity. However, for [Formula: see text], the thermal conductivity rises remarkably. As an overall result, the maximum value of dimensionless TE figure of merit (ZT) reaches 1.52 at 873 K for the sample of [Formula: see text], 36.5% higher than for the sample without [Formula: see text].

Structure and thermoelectric properties of the n-type clathrate Ba8Cu5.1Ge40.2Sn0.7

2015 ◽  
Vol 3 (37) ◽  
pp. 19100-19106 ◽  
Author(s):  
Jingtao Xu ◽  
Jiazhen Wu ◽  
Hezhu Shao ◽  
Satoshi Heguri ◽  
Yoichi Tanabe ◽  
...  
Keyword(s):  
Single Crystals ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Type I ◽  
Thermoelectric Figure Of Merit ◽  
Flux Method ◽  
Thermoelectric Figure ◽  
Space Group ◽  
Maximum Value ◽  
Study Type

We study type I clathrate Ba8Cu5.1Ge40.2Sn0.7 single crystals (space group Pm3̄n, no. 223, a = 10.7151(3)) grown using a Sn flux method, and the thermoelectric figure of merit ZT of single crystals reaches a maximum value of 0.6 at 773 K.

The Enhanced Thermoelectric Properties of Ba0.4Co4Sb11.7Te0.3 Prepared by the High-Pressure and High-Temperature Method

2014 ◽  
Vol 33 (1) ◽  
pp. 59-63
Author(s):  
Song Hao ◽  
Hong An Ma ◽  
Le Deng ◽  
Kai Kai Jie ◽  
Zhe Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Thermoelectric Figure Of Merit ◽  
X Ray Diffraction ◽  
Thermoelectric Figure ◽  
Seebeck Coefficients ◽  
Temperature Method ◽  
Increasing Temperature

AbstractPolycrystalline skutterudite Ba0.4Co4Sb11.7Te0.3 with a bcc crystal structure was prepared by the High-Pressure and High-Temperature (HPHT) method. The study explored a chemical method for introducing Ba atoms into the voids of CoSb3 to optimize the thermoelectric figure of merit ZT in the system of Ba0.4Co4Sb11.7Te0.3. The samples were characterized by X-ray diffraction, electron microprobe analysis, and thermoelectric properties measurement. The electrical resistivity, Seebeck coefficients and thermal conductivities of the samples were measured in the temperature range of 300–743 K. The power factor and the figure of merit, ZT, of the samples all increased with the increasing temperature. A dimensionless thermoelectric figure of merit of 0.87 at 743 K was achieved for n-type Ba0.4Co4Sb11.7Te0.3 at last. The results indicated Ba-filled CoSb3 prepared by HPHT method is an effective method to greatly enhance the thermoelectric properties of skutterudite compounds.

Enhanced thermoelectric properties of the hole-doped Bi2−xKxSr2Co2Oy ceramics

2015 ◽  
Vol 29 (28) ◽  
pp. 1550192 ◽  
Author(s):  
Feng Gao ◽  
Qinglin He ◽  
Ruijuan Cao ◽  
Fang Wu ◽  
Xing Hu ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Solid State Reaction Method ◽  
Undoped Sample ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Element Doping ◽  
P Type ◽  
Remarkable Reduction

In this paper, the influence of K element doping on the thermoelectric properties of the [Formula: see text] (x = 0.00, 0.05, 0.10, 0.15, and 0.20) samples prepared by the solid-state reaction method were investigated from 333 K to 973 K. It was shown that due to the p-type K doping the electrical resistivity of the doped sample can be reduced remarkably as compared with the undoped sample, especially for the optimum doped sample [Formula: see text]. The Seebeck coefficients of the K doped samples have only a slight decrease as compared with the undoped sample. As a result of the remarkable reduction of the electrical resistivity the power factor of the doped sample have a significant improvement. The thermal conductivity of the samples is depressed due to the defects caused by K doping. As an overall result, the dimensionless figure of merit (ZT) of the [Formula: see text] sample reaches a maximum value of 0.3 at 973 K, being 93% higher than that of the undoped sample.

Enhanced thermoelectric properties of Hg-doped Cu2Se

2018 ◽  
Vol 32 (08) ◽  
pp. 1850087 ◽  
Author(s):  
Erying Li ◽  
Siqi Wang ◽  
Zheng Zhu ◽  
Ruijuan Cao ◽  
Xing Hu ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Cation Vacancies ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Electrical Resistivities ◽  
Higher Temperature ◽  
Bulk Alloys ◽  
Thermal Conductivities

The Cu[Formula: see text]Hg[Formula: see text]Se (x = 0, 0.05, 0.10 and 0.15) nanopowders were fabricated using the hydrothermal synthesis, and then hot-pressed into bulk alloys. The effects of Hg doping on the thermoelectric (TE) properties of Cu2Se were investigated. The electrical resistivities of all the doped samples are lower than that of the nondoped sample due to the induced cation vacancies. For the x = 0.10 and x = 0.15 samples, Seebeck coefficients increase slightly compared with the nondoped sample at higher temperature. Except for the sample of x = 0.05, the thermal conductivities of x = 0.10 and x = 0.15 samples are substantially lower than that of the x = 0.00 sample. As an overall result, the maximum value of ZT, which is the dimensionless TE figure of merit, reaches 1.50 at 600[Formula: see text]C for the x = 0.10 sample.

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.

scholarly journals Mechanosynthesis and Thermoelectric Properties of Fe, Zn, and Cd-Doped P-Type Tetrahedrite: Cu12-xMxSb4S13

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3448
Author(s):  
Francisco Arturo López Cota ◽  
José Alonso Díaz-Guillén ◽  
Oscar Juan Dura ◽  
Marco Antonio López de la Torre ◽  
Joelis Rodríguez-Hernández ◽  
...  
Keyword(s):  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Powder Processing ◽  
High Energy ◽  
Secondary Phases ◽  
Ambient Conditions ◽  
Cadmium Sulfate ◽  
Electrical Conductivities ◽  
Compositional Changes ◽  
P Type

This contribution deals with the mechanochemical synthesis, characterization, and thermoelectric properties of tetrahedrite-based materials, Cu12-xMxSb4S13 (M = Fe2+, Zn2+, Cd2+; x = 0, 1.5, 2). High-energy mechanical milling allows obtaining pristine and substituted tetrahedrites, after short milling under ambient conditions, of stoichiometric mixtures of the corresponding commercially available binary sulfides, i.e., Cu2S, CuS, Sb2S3, and MS (M = Fe2+, Zn2+, Cd2+). All the target materials but those containing Cd were obtained as single-phase products; some admixture of a hydrated cadmium sulfate was also identified by XRD as a by-product when synthesizing Cu10Cd2Sb4S13. The as-obtained products were thermally stable when firing in argon up to a temperature of 350–400 °C. Overall, the substitution of Cu(II) by Fe(II), Zn(II), or Cd(II) reduces tetrahedrites’ thermal and electrical conductivities but increases the Seebeck coefficient. Unfortunately, the values of the thermoelectric figure of merit obtained in this study are in general lower than those found in the literature for similar samples obtained by other powder processing methods; slight compositional changes, undetected secondary phases, and/or deficient sintering might account for some of these discrepancies.

Thermoelectric Properties of n-Type 90% Bi2Te3+10%Bi2Se3 Thermoelectric Materials Produced by Melt Spinning Method and Sintering

2007 ◽  
Vol 534-536 ◽  
pp. 161-164 ◽  
Author(s):  
Taek Soo Kim ◽  
Byong Sun Chun
Keyword(s):  
Solid Solutions ◽  
Thermoelectric Materials ◽  
Figure Of Merit ◽  
Melt Spinning ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Thermoelectric Figure Of Merit ◽  
Vacuum Sintering ◽  
Thermoelectric Figure ◽  
Sintering Processes

N-type Bi2Te3-Sb2Te3 solid solutions doped with CdCl2 was prepared by melt spinning, crushing and vacuum sintering processes. Microstructure, bending strength and thermoelectric property were investigated as a function of the doping quantity from 0.03wt.% to 0.10wt.% and sintering temperature from 400oC to 500oC, and finally compared with those of conventionally fabricated alloys. The alloy showed a good structural homogeneity as well as bending strength of 3.88Kgf/mm2. The highest thermoelectric figure of merit was obtained by doping 0.03wt.% and sintering at 500oC.

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.

Study on Phases and Thermoelectric Properties of Bulk Fe4Sb12 and Fe3CoSb12 Prepared by Milling and Sintering

2011 ◽  
Vol 121-126 ◽  
pp. 1526-1529
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Thermoelectric Properties ◽  
Impurity Phase ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Type Semiconductor ◽  
P Type

Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.

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