Ca3Co2O6 for High Temperature Side of Thermoelectric FGM

2009 ◽  
Vol 631-632 ◽  
pp. 489-494
Author(s):  
Takeo Uesugi ◽  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Thermoelectric Properties ◽  
Thermoelectric Material ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
High Performance ◽  
Waste Heat ◽  
High Temperature Side ◽  
Temperature Range

In modern age, much thermal energy is emitted from ceramic and/or steel industries. Their temperature range is between 500 K and 1300 K. Thermoelectric materials are promising to utilize the waste heat, because of no CO2 emission and long life due to no moving parts. The thermoelectric properties of every thermoelectric material have temperature dependence and high performance appears at a specific temperature range. If the proper materials are placed and joined along the temperature gradient to form an FGM, the performance should be higher than a monolithic material. The performance of a thermoelectric material is expressed by the dimensionless figure of merit ZT=α2ρ-1κ -1T, where α is the Seebeck coefficient, ρ is the electrical resistivity, κ is the thermal conductivity, and T is absolute temperature. Thermoelectric oxides are suitable for high temperature materials because of chemical stability. NaxCoO2 shows relatively high ZT value in thermoelectric oxide at the temperature range below 800 K. Ca3Co4O9 shows ZT ~1 at 1000 K. Recently, it is reported that Ca3Co2O6 that is formed by decomposition of Ca3Co4O9 at 1173 K has high performance at 1300 K. The properties and fabrication condition of high density Ca3Co2O6 are, however, not reported in detail. In order to improve the thermoelectric properties and to shift the temperature range for Ca3Co2O6, we investigated the effects of element substitution. In this experiment, the sintered Ca3Co2-xMxO6 (x=0 or 0.2, M= Mn, Mo or V) were prepared by solid-state reaction or hot pressing. Relative density of Ca3Co2O6 by hot-pressing (HP) was over 94% which is larger than one of Ca3Co2O6 by solid-state reaction (SSR). The resistivity of Mo- or V-substituted Ca3Co2O6 (HP-Mo or HP-V) were lower than one of non-substituted Ca3Co2O6 (HP). The resistivity of Mo-substituted Ca3Co2O6 (HP-Mo) showed the lowest value of 4.3×10-2 Ωcm in all specimens at 1181 K. The power factor α2ρ-1 of Ca3Co2O6 (HP-Mo) was 64.2 Wm-1K-2, which is the largest of all specimens at 1178 K, and this value is approximately 1.3 times higher than 48.8 Wm-1K-2 for Ca3Co2O6 (HP).

Thermoelectric Properties of High Density Sintered Ca3Co2O6

2008 ◽  
Vol 54 ◽  
pp. 211-215 ◽  
Author(s):  
Takeo Uesugi ◽  
Hitoshi Kohri ◽  
Ichiro Shiota ◽  
Masahiko Kato ◽  
Isao J. Ohsugi
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Hot Pressing ◽  
Temperature Limit ◽  
Thermoelectric Oxide ◽  
Temperature Range ◽  
Seebeck Coefficients ◽  
The One ◽  
Lower Resistivity

Ca3Co4O9 is a promising material for thermoelectric generation, as it is stable up to 1173 K in the air, and shows good thermoelectric properties. Recently, it was found that Ca3Co2O6 was stable up to 1300 K in the air. The Ca3Co2O6 is decomposed phase of Ca3Co4O9 and the temperature limit is higher than one of Ca3Co4O9. The electrical resistivity of Ca3Co2O6 was, however, higher than the one of Ca3Co4O9. Not only high power generation performances but also excellent strength is required for practical use of the thermoelectric oxide materials. Polycrystalline samples of Ca3Co2O6 were prepared by solid-state reaction (SSR) and hot pressing (HP). Relative density of Ca3Co2O6 (HP) was over 98%, which is larger than the one of Ca3Co2O6 (SSR). Ca3Co2O6 (HP) showed larger strength and lower resistivity than Ca3Co2O6 (SSR). The resistivity (ρ) of Ca3Co2O6 (HP) in perpendicular to the pressurized direction decreased from 64 Ωcm to 4.0×10-2 Ωcm at the temperature range between 373 and 1173 K. In addition, the resistivity of this sample was decreased by heat treatment in the air. The Seebeck coefficients (S) of Ca3Co2O6 (HP) was positive value and more than 160 μVK-1 at the temperature range between 373 and 1173 K. Ca3Co1.8M0.2O6 (M= Mn or V) were prepared by solid state reaction and hot pressing. The resistivity of Mn-substituted Ca3Co2O6 (HP-Mn) and V-substituted Ca3Co2O6 (HP-V) were lower than the one of non-substituted Ca3Co2O6 (HP) at the temperature below 523 K for the Mn-substituted sample or 723 K for V-substituted sample. The latter showed the lowest value 1.53 Ωcm of all specimens at 383 K. The power factor (S2ρ-1) of Ca3Co2O6 (HP) was 88.3 μWm-1K-2, which is the largest of all specimens at 1176 K, but S2ρ-1 of V-substituted Ca3Co2O6 (HP-V) is the largest of all specimens up to 773 K.

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.

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.

Development of the High Performance Thermoelectric Modules for High Temperature Heat Sources

2007 ◽  
Vol 534-536 ◽  
pp. 1521-1524 ◽  
Author(s):  
Takahiro Jinushi ◽  
Masahiro Okahara ◽  
Zenzo Ishijima ◽  
Hideo Shikata ◽  
Mitsuru Kambe
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Waste Heat ◽  
Module Structure ◽  
High Temperature Side ◽  
Powder Metallurgy Process ◽  
Stress Diffusion ◽  
Carbon Sheet ◽  
Metallurgy Process ◽  
Temperature Side

In recent years, power generating systems using thermoelectric elements have become attractive as an effective method of using industrial waste heat, at a temperature of around 773K, to produce energy. However, in order to develop a module usable under such a high temperature, certain concerns have to be overcome, e.g. thermal stress, diffusion of the connecting interfaces, etc. In this research, using an FeSi2 with diffusion barrier layers and a SiGe element produced by a powder metallurgy process, the module structure and installation method were optimized for application in PM sintering furnaces. As a result, from a viewpoint of heat stress at high temperatures and contact thermal resistance, it is confirmed that the optimal structure is the skeleton structure using Cu substrate on the cooling side, which has excellent heat conductivity and the optimal installation method is to adopt a carbon sheet and a mica sheet to the high temperature side, where Si grease is applied to the low temperature side, under pressurized condition. The power of the developed modules indicated 0.5W in an FeSi2 module and 3.8 W with a SiGe module at 827K, respectively. Moreover, neither breakage nor deterioration were observed after 30 heat cycles test simulating sintering furnace.

scholarly journals Thermoelectric Properties of MnSi1.74-1.75:Gem Prepared by Solid-State Reaction and Hot Pressing

2019 ◽  
Vol 57 (4) ◽  
pp. 264-269
Author(s):  
In-Jae Lee ◽  
Sol-Bin Park ◽  
Soon-Chul Ur ◽  
Kyung-Wook Jang ◽  
Il-Ho Kim
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Hot Pressing

Solid-state reaction of niobium with diamond carbon at high pressure and high temperature to form superconducting composite

2021 ◽  
Vol 31 (3) ◽  
pp. 415-418
Author(s):  
Vladimir Yu. Osipov ◽  
Fedor M. Shakhov ◽  
Nikolai M. Romanov ◽  
Kazuyuki Takai
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reaction

Supported High Temperature Protonic Films Produced by Solid State Reaction

ChemInform ◽  
2007 ◽  
Vol 38 (38) ◽  
Author(s):  
Wilhelm A. Meulenberg ◽  
Jose M. Serra
Keyword(s):  
High Temperature ◽  
Solid State ◽  
Solid State Reaction

scholarly journals Thermoelectric properties of Cu3SbSe3 with intrinsically ultralow lattice thermal conductivity

2014 ◽  
Vol 2 (38) ◽  
pp. 15829-15835 ◽  
Author(s):  
Kriti Tyagi ◽  
Bhasker Gahtori ◽  
Sivaiah Bathula ◽  
A. K. Srivastava ◽  
A. K. Shukla ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Spark Plasma Sintering ◽  
Thermoelectric Properties ◽  
Solid State Reaction ◽  
Electrical Transport ◽  
Single Phase ◽  
Lattice Thermal Conductivity ◽  
Plasma Sintering ◽  
Spark Plasma

Intrinsically ultra-low thermal conductivity and electrical transport in single-phase Cu2SbSe3 synthesized employing a solid state reaction and spark plasma sintering.

Thermoelectric properties of Sb-doped tin oxide by a one-step solid-state reaction

2021 ◽  
Author(s):  
Leilane R. Macario ◽  
Andrew Golabek ◽  
Holger Kleinke ◽  
Edson R. Leite
Keyword(s):  
Solid State ◽  
Thermoelectric Properties ◽  
Tin Oxide ◽  
Solid State Reaction ◽  
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