Investigation of Preparation and Thermoelectric Properties of Ca2.5La0.5Co4O9 Porous Ceramics

2015 ◽  
Vol 1120-1121 ◽  
pp. 98-101
Author(s):  
Peng Xia Ji ◽  
Hui Min Zhang ◽  
Ai Min Chang
Keyword(s):  
Electrical Resistivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Solid State Reaction ◽  
Porous Ceramics ◽  
Pore Former ◽  
Higher Power

CO(NH2)2 as pore-former used to prepare porous Ca2.5La0.5Co4O9 thermoelectric materialsby solid-state reaction technique.Microstructure,density and thermoelectric properties (temperature dependence of electrical resistivity,Seebeck coefficient) of the samples were studied in details.The results have shown that the porosity increases and the pore structure is improved with the pore-former content increasing,and electrical resistivity and density decrease while Seebeck coefficient raise.The improvement in electrical resistivity and Seebeck coefficient leads to higher power factor values at 913 K (around 1.32 mW/cm·K2) than undoped samples.

Lanthanide Based Ternary Intermetallics as Advanced Thermoelectric Materials

2006 ◽  
Vol 980 ◽  
Author(s):  
Ken Kurosaki ◽  
Takeyuki Sekimoto ◽  
Kenta Kawano ◽  
Hiroaki Muta ◽  
Shinsuke Yamanaka
Keyword(s):  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
High Temperatures ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Single Phase ◽  
Type Structure ◽  
Large Power

AbstractPolycrystalline ingots of the lanthanide based ternary intermetallics: LaNiSb, GdNiSb, ErNiSb and ErPdSb were prepared and characterized. The thermoelectric properties of ErNiSb and ErPdSb were measured at high temperatures. We succeeded in preparing the single phase ingots of ErNiSb and ErPdSb, while the ingots of LaNiSb and GdNiSb contain appreciable quantities of the impurity phases. ErNiSb and ErPdSb crystallize the MgAgAs-type structure (half-Heusler structure). ErNiSb and ErPdSb indicate positive values of the Seebeck coefficient. The values at room temperature are 36 and 240 micro VK-1 for ErNiSb and ErPdSb, respectively. The electrical resistivity of ErNiSb and ErPdSb decreases with temperature, indicating semiconductor-like behavior. ErPdSb exhibits a relatively large power factor 1.5x10-3 Wm-1K-2 at around 700 K, which is approximately two times larger than that of ErNiSb.

Na-Site Doping of NaCo2O4 Thermoelectric Materials

2007 ◽  
Vol 336-338 ◽  
pp. 802-804 ◽  
Author(s):  
Ying Li ◽  
Li Hua Zhang ◽  
Shu Lan Wang ◽  
Gui Ying Xu ◽  
Mao Fa Jiang
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Thermoelectric Materials ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Maximum Power ◽  
Reaction Method

The K, Ca, Sr and Ce doped and non-doped γ-NaxCo2O4 samples were prepared by the solid-state reaction method. Results show that the Na-site doping might lead to an increase in the Seebeck coefficient and a decrease in the electrical conductivity of the samples. The maximum power factors of the K, Ca and Sr doped samples are respectively 2.04, 1.93 and 1.9 W·m-1·K-2, corresponding to an increase by 58%, 50% and 47% compared with that of the non-doped samples. Thus, the Na-site doping can improve the thermoelectric properties of γ-NaxCo2O4 oxides.

Thermoelectric Generating Properties of Perovskite Like Materials

2010 ◽  
Vol 74 ◽  
pp. 72-76 ◽  
Author(s):  
Hitoshi Kohri ◽  
Masahiko Kato ◽  
Isao J. Ohsugi ◽  
Ichiro Shiota
Keyword(s):  
Electrical Resistivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
High Performance ◽  
Waste Heat ◽  
Perovskite Layer ◽  
High Seebeck Coefficient

Research and development of thermoelectric generators have been actively carried out to use waste heat. It is well known some p-type oxides show high thermoelectric performance. However, an n-type oxide with high performance has not been found. An n-type CaMnO3 is a promising material because of its high Seebeck coefficient. The electrical resistivity of this oxide is, however, too high to use it practically. Not only high Seebeck coefficient but also low electrical resistivity is required for practical use. At first, we investigated the effects of element substitution in order to decrease the resistivity. N-type CaMn0.9M0.1O3 (M=Cu, In) compounds were prepared by solid-state reaction and hot pressing. The maximum value of power factor for CaMn0.9In0.1O3 was 0.204 mWm-1K-2, which was the largest of all specimens at 673 K. This value was, however, not enough to use it practically. Secondly, we focus attention on Aurivillius compounds. The Aurivillius compounds consist of Perovskite layers and Bi-O layers. We expect that this crystal structure shows large Seebeck coefficient due to the quantum confinement of electron in Perovskite layer. Bi2VO5.5 with Aurivillius structure was prepared by solid-state reaction and hot pressing. The Seebeck coefficient of Bi2VO5.5 decreased with increasing temperature and was positive value below 600 K and was negative value above 600 K. The power factor of annealed Bi2VO5.5 showed the highest value of all specimens at the temperature range above 800 K.

Influence of R3+ ion sizes on the thermoelectric properties of RBaCo4O7+δ ceramics

2015 ◽  
Vol 29 (26) ◽  
pp. 1550154 ◽  
Author(s):  
F. Gao ◽  
Q. L. He ◽  
F. Wu ◽  
D. L. Yang ◽  
X. Hu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Oxygen Adsorption ◽  
Reaction Method ◽  
Transition Phenomenon ◽  
Seebeck Coefficients

The influence of [Formula: see text] ion sizes on the electrical resistivity, Seebeck coefficients, thermal conductivity and [Formula: see text] values of [Formula: see text] prepared by the solid-state reaction method was investigated from 373 K to 973 K. The electrical resistivity decreases with decreasing [Formula: see text] ion sizes. Both the electrical resistivity and the Seebeck coefficients have a transition at about 630 K. Especially, the transition phenomenon disappears gradually with decreasing [Formula: see text] ion sizes, and is attributed to the oxygen adsorption of [Formula: see text]. The [Formula: see text] values increase with rising temperature or decreasing [Formula: see text] ion sizes. The [Formula: see text] with the smallest [Formula: see text] size has the maximum [Formula: see text] value that reaches 0.1 at 973 K.

TEXTURED STRUCTURE AND ANISOTROPIC THERMOELECTRIC PROPERTIES OF Ca2.7Bi0.3Co4O9 OXIDE PREPARED BY CONVENTIONAL SOLID-STATE REACTION

2009 ◽  
Vol 23 (01) ◽  
pp. 87-95 ◽  
Author(s):  
HAOSHAN HAO ◽  
QINGLIN HE ◽  
CHANGQING CHEN ◽  
HONGWEI SUN ◽  
XING HU
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Conventional Solid State Reaction ◽  
Reaction Method ◽  
Bi Doping

Ca 3-x Bi x Co 4 O 9(x = 0.0, 0.3) samples have been prepared at 1223 K by conventional solid-state reaction method. XRD and SEM investigations reveal that c-axis-oriented structure could be formed in Ca 2.7 Bi 0.3 Co 4 O 9 samples, whereas grains in Ca 3 Co 4 O 9 samples distribute randomly. Moreover, Bi doping increases the grain size and relative density of Ca 2.7 Bi 0.3 Co 4 O 9. The electrical conductivity along the ab plane for Ca 2.7 Bi 0.3 Co 4 O 9 is about four times as large as that along the c-axis, but the Seebeck coefficient is almost isotropic, which leads to a remarkable rise of the power factor in ab plane for Ca 2.7 Bi 0.3 Co 4 O 9 compared with untextured Ca 3 Co 4 O 9. The textured structure in Ca 2.7 Bi 0.3 Co 4 O 9 sample should be attributed to the effect of Bi doping.

High-Temperature Thermoelectric Properties of Pb- and La-Substituted Bi2Sr2Co2Oy Misfit Compounds

2010 ◽  
Vol 105-106 ◽  
pp. 336-338 ◽  
Author(s):  
Hao Shan Hao ◽  
Jin Qin Ye ◽  
Yong Tao Liu ◽  
Xing Hu
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Thermoelectric Performance ◽  
Simultaneous Increase ◽  
Reaction Method ◽  
Seebeck Coefficients

Pb- and La-substituted (Bi,Pb)2(Sr,La)2Co2Oy samples were prepared by solid-state reaction method and the effect of element substitution on the high-temperature thermoelectric properties was investigated. It was found that the presence of Pb and La elements improved the thermoelectric properties of the Bi2Sr2Co2Oy system owing to the simultaneous increase of conductivity and Seebeck coefficients. The optimal thermoelectric performance was obtained in Pb and La co-substituted samples and the power factor could reach 2.1×10-4Wm-1K-2 at 1000K.

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.

Study of thermoelectric properties of Ca-doped LaCoO3

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540026 ◽  
Author(s):  
Kei-Ichiro Murai ◽  
Ken Nagai ◽  
Masaru Takahashi ◽  
Shosuke Takakusa ◽  
Toshihiro Moriga
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Ca Substitution

The samples of La 1-x Ca x CoO 3 (x = 0, 0.05, 0.10, 0.15) were synthesized by solid state reaction method for studying thermoelectric properties. The properties of electrical conductivity and Seebeck coefficient were measured in the temperature ranging from room temperature to 573 K. The results of electrical conductivity was increasing Ca substitution. The highest value of electrical conductivity is 1574 S/cm. It is concluded that Ca 2+ doping in LaCoO 3 has the effect to inhibit Seebeck coefficient from decreasing.

Thermoelectric properties of Zn-Sn-Sb based alloys

2011 ◽  
Vol 1314 ◽  
Author(s):  
Motoki Ito ◽  
Yuji Ohishi ◽  
Hiroaki Muta ◽  
Ken Kurosaki ◽  
Shinsuke Yamanaka
Keyword(s):  
Ternary System ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Thermoelectric Materials ◽  
Volume Fraction ◽  
Chalcopyrite Structure ◽  
Effective Dopant ◽  
Sn Substitution

ABSTRACTIn the Zn-Sn-Sb ternary system, Zn4Sb3, ZnSnSb2, and ZnSb have attracted attentions as advanced thermoelectric materials. Zn-Sn-Sb based alloys with various compositions were fabricated and the thermoelectric properties were investigated. That system is composed by orthorhombic ZnSb phase, tetragonal ZnSnSb2 phase with chalcopyrite structure, and rhombohedral SnSb phase. Large Sn content increases volume fraction of the metallic SnSb phase, which degenerate the powar factor. The ZnSb based alloy shows relatively large Seebeck coefficient. Sn substitution for ZnMxSb1-x significantly enhances the power factor, which indicates that Sn is effective dopant for ZnSb.

Enhanced Thermoelectric Properties of FeSbx Nanocomposites Through Stoichiometric Adjustment

2012 ◽  
Vol 1456 ◽  
Author(s):  
Mani Pokharel ◽  
Huaizhou Zhao ◽  
Kevin Lukas ◽  
Zhifeng Ren ◽  
Cyril Opeil
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Carrier Concentration ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Hall Coefficient

ABSTRACTThe Seebeck coefficient, electrical resistivity, thermal conductivity and Hall coefficient of FeSbx (x = 2.04, 2.00, and 1.96) nanocomposites hot pressed at 300 °C were measured. The power factor of FeSb1.96 was increased by 105% compared to FeSb2. Hall coefficient measurements revealed a decreased carrier concentration and increased mobility in FeSb1.96 with an overall enhancement in ZTof 45% in FeSb1.96 .

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