Dramatically Enhanced Thermoelectric Properties of Ca3Co4Oy by Large Amount of RE Substitution

ABSTRACTWe report the synthesis and thermoelectric properties of [(Ca1-xREx)2CoO3-δ]0.62CoO2 compounds (RE: rare earth element, RE = Y, Sm, Eu, Tb, Dy, Ho and Lu). From optimization of synthesis conditions, all the chosen RE in this study were able to be substituted for the Ca sites in the block layers up to x = 0.25. In the case of RE = Tb, at 1150 K, only κ was systematically decreased with x, while both Seebeck coefficient (S) and resistivity (ρ) were almost constant for the charge of x. Consequently, the dimensionless figure of merit (ZT) was increased with x and reached 0.2 at 1150 K for x = 0.25. Moreover, interestingly, it was found that S and ρ at 300 K were enhanced with ionic radius of the doped trivalent RE ions in spite of the doping of equivalent RE ions. This is probably because local structures of oxygen sites around Co ion in the CoO2 layers largely depend on kinds of the doped RE.

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Study on Mechanisms of Rare Earth Elements on Improving Thermoelectric Properties of RExCo4Sb12

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.71-78.3737 ◽

2011 ◽

Vol 71-78 ◽

pp. 3737-3740

Author(s):

Ke Gao Liu ◽

Jing Li

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Mechanical Alloy ◽

Spark Plasma Sintering ◽

Thermoelectric Properties ◽

Rare Earth Element ◽

Figure Of Merit ◽

Earth Element ◽

Plasma Sintering ◽

Spark Plasma

It is the important way to improve thermoelectric properties of skutterudite materials by doping with rare earth elements. The mechanisms of improving properties of bulk RExCo4Sb12materials prepared by mechanical alloy and spark plasma sintering (MA-SPS) at 650°C were investigated by analyzing the composition, microstructure and atomic occupying locations. According the results it can be considered that the mechanism to improve the thermoelectric properties of rare earth elements is that rare earth element Ce in the samples mainly plays the doping role in reducing the resistivity of the sample and improving the conductivity, so that it makes the figure of merit ZT of samples increase significantly.

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Alkaline-earth metal and rare-earth element incorporation control by ionic radius and growth rate on a stalagmite from the Chauvet Cave, Southeastern France

Chemical Geology ◽

10.1016/j.chemgeo.2011.08.006 ◽

2011 ◽

Vol 290 (1-2) ◽

pp. 1-11 ◽

Cited By ~ 32

Author(s):

Clément Bourdin ◽

Eric Douville ◽

Dominique Genty

Keyword(s):

Growth Rate ◽

Rare Earth ◽

Rare Earth Element ◽

Alkaline Earth ◽

Ionic Radius ◽

Earth Element ◽

Earth Metal ◽

Alkaline Earth Metal

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The effect of light rare earth element substitution in Yb14MnSb11on thermoelectric properties

Journal of Materials Chemistry C ◽

10.1039/c5tc02326b ◽

2015 ◽

Vol 3 (40) ◽

pp. 10566-10573 ◽

Cited By ~ 27

Author(s):

Yufei Hu ◽

Sabah K. Bux ◽

Jason H. Grebenkemper ◽

Susan M. Kauzlarich

Keyword(s):

Rare Earth ◽

Carrier Concentration ◽

Thermoelectric Properties ◽

Rare Earth Element ◽

Earth Element ◽

Light Rare Earth Element ◽

Light Rare Earth ◽

Element Substitution ◽

Effect Of Light

ThezTof Yb14MnSb11is improved by the introduction of a light rare earth element, RE3+(RE = Pr, Sm) with partially filled f-levels. The carrier concentration is reduced upon substituting RE3+for Yb2+, adding one electron to the system and improving thezTvalues 30–40% over that of the pristine material.

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Synthesis of Rare Earth Element-Iron-Oxygen Ultrafine Particles by Using Inductively Coupled Plasma-Relation between Ionic Radius of Rare Earth Element and Products-

Journal of the Society of Powder Technology Japan ◽

10.4164/sptj.40.720 ◽

2003 ◽

Vol 40 (10) ◽

pp. 720-728 ◽

Cited By ~ 1

Author(s):

Masami Sugasawa ◽

Nobuyuki Kikukawa ◽

Yoshinobu Nagano ◽

Naoyuki Kayano ◽

Takayasu Kimura

Keyword(s):

Rare Earth ◽

Rare Earth Element ◽

Inductively Coupled Plasma ◽

Ultrafine Particles ◽

Ionic Radius ◽

Earth Element ◽

Inductively Coupled

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Preparation and Thermoelectric Properties of Bi-Doped Mg2Si Nanocomposites

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.66.17 ◽

2009 ◽

Vol 66 ◽

pp. 17-20 ◽

Cited By ~ 18

Author(s):

Mei Jun Yang ◽

Wei Jun Luo ◽

Qiang Shen ◽

Hong Yi Jiang ◽

Lian Meng Zhang

Keyword(s):

Thermal Conductivity ◽

Electrical Conductivity ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Figure Of Merit ◽

Dimensionless Figure Of Merit ◽

Plasma Sintering ◽

Spark Plasma ◽

Heavy Doping ◽

Nanocomposite Structures

Nanocomposites and heavy doping both are regarded as effective way to improve materials’ thermoelectric properties. 0.7at% Bi-doped Mg2Si nanocomposites were prepared by spark plasma sintering. Results of thermoelectric properties tests show that the doping of Bi atom effectively improves the electrical conductivity of Mg2Si，and the nanocomposite structures are helpful to reduce thermal conductivity and increase Seebeck coefficient, hence improving the thermoelectric performance. A maximum dimensionless figure of merit of 0.8 is obtained for the Bi-doped Mg2Si nanocomposite with 50 wt % nanopowder inclusions at 823K, about 63% higher than that of Bi-doped Mg2Si sample without nanopowder inclusions and 119% higher than that of microsized Mg2Si sample without Bi-doped, respectively.

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Local Structures of Si2(O,N)7 Ditetrahedra in J-Phase

Materials Science Forum ◽

10.4028/www.scientific.net/msf.554.43 ◽

2007 ◽

Vol 554 ◽

pp. 43-49 ◽

Cited By ~ 1

Author(s):

Junichi Takahashi ◽

M. Shimada ◽

H. Yamane

Keyword(s):

Monte Carlo ◽

Rare Earth ◽

Monte Carlo Method ◽

Nitrogen Atom ◽

Rare Earth Element ◽

Earth Element ◽

Phase Model ◽

Distribution Models ◽

Local Structures ◽

The Monte Carlo Method

Oxygen/nitrogen (O/N) configuration in RE-J-phase, RE4Si2O7N2 (RE = rare earth element), was simulated by the Monte Carlo method applied to O/N distribution models. Proportion of local structures of Si2(O,N)7 ditetrahedra and Si(O,N)4 tetrahedra in the J-phase was quantitatively assessed. For the Lu-J-phase model with the bridging site between two Si atoms being occupied by nitrogen atom, the Si2(O,N)7 ditetrahedra composed of O3≡Si–N–Si≡O2N (> 40 %), O3≡Si–N–Si≡O3 (c.a. 30 %), and O2N≡Si–N–Si≡O2N(c.a. 15 %). Tetrahedra of SiO3N and SiO2N2 were dominant and small amount of SiON3 tetrahedra coexisted. For La-J-phase model with the O/N occupancy of 0.1/0.9 at the bridging site, configurations of O3≡Si–O–Si≡O2N (c.a. 5%), O3≡Si–O–Si≡O3 (c.a. 3%), and O2N≡Si–O–Si≡O2N (c.a. 2%) were demonstrated in addition to the three configurations of ditretrahedra recognized in the Lu-J-phase. In La-J-phase coexistence of SiO4 tetrahedra was presented.

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Directional Thermoelectric Performance of Ru2Si3

MRS Proceedings ◽

10.1557/proc-842-s4.6 ◽

2004 ◽

Vol 842 ◽

Author(s):

Benjamin A. Simkin ◽

Yoshinori Hayashi ◽

Haruyuki Inui

Keyword(s):

High Temperature ◽

Seebeck Coefficient ◽

Domain Structure ◽

Thermoelectric Properties ◽

Crystal Orientation ◽

Figure Of Merit ◽

Orthorhombic Phase ◽

Thermoelectric Performance ◽

Dimensionless Figure Of Merit ◽

Principal Axes

ABSTRACTThe orthorhombic compound Ru2Si3 is currently of interest as a high-temperature thermoelectric material. In order to clarify the effects of crystal orientation on the thermoelectric properties of Ru2Si3, we have examined the microstructure, Seebeck coefficient, electrical resistivity, and thermal conductivity of Ru2Si3 along the three principal axes, using these measured quantities to describe the relative thermoelectric performance as a property of crystal orientation. Ru2Si3 undergoes a high temperature (HT)→low temperature (LT) phase change and polycrystalline Si platelet precipitation during cooling, both of which are expected to effect the thermoelectric properties. The HT tetragonal→LT orthorhombic phase transformation results in a [010]//[010], [100]//[001] two-domain structure, while polycrystalline Si precipitation occurs on the (100)LT and (001)LT planes. The [010] orientation is found to posses superior thermoelectric properties (with the dimensionless figure of merit, ZT[010]/ZT[100]>4 at 650°C), due principally to the larger Seebeck coefficient along the [010] direction. The effect of the domain structure on the thermoelectric properties is discussed.

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The thermoelectric properties of CoSb3 compound doped with Te and Sn synthesized at different pressure

Modern Physics Letters B ◽

10.1142/s021798491750261x ◽

2017 ◽

Vol 31 (28) ◽

pp. 1750261 ◽

Cited By ~ 2

Author(s):

Yiping Jiang ◽

Xiaopeng Jia ◽

Hongan Ma

Keyword(s):

Thermal Conductivity ◽

High Pressure ◽

Electrical Resistivity ◽

High Temperature ◽

Seebeck Coefficient ◽

Thermoelectric Properties ◽

Figure Of Merit ◽

Raw Materials ◽

Absolute Value ◽

Dimensionless Figure Of Merit

The skutterudite CoSb[Formula: see text]Te[Formula: see text]Sn[Formula: see text] compound was synthesized successfully by high pressure and high temperature (HPHT) method using Co, Sb, Te and Sn powder as raw materials. The effects of pressure on its structure and the thermoelectric properties are investigated systematically from 300 K to 800 K. The electrical resistivity and the absolute value of the Seebeck coefficient for the sample increases with rising synthetic pressure. The thermal conductivity of the sample decreases with synthetic pressure and temperature rising in the range of 300–800 K. In this study, the maximum dimensionless figure of merit (ZT) value of 1.17 has been achieved at 793 K, 3 GPa for this thermoelectric material.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.750.130 ◽

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.

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