Enhanced ZT of Ca3Co4O9 by nano-sized precursor

2021 ◽  
Author(s):  
Wanatchaporn Namhongsa ◽  
Tosawat Seetawan
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Electrical Resistivity ◽  
Solid State ◽  
Power Factor ◽  
Solid State Reaction ◽  
Hot Press ◽  
Sintering Time ◽  
Main Effect ◽  
Press Method

Abstract Ca3Co4O9 sample synthesized from nanometer of CaCO3 and Co2O3 sized precursor has been prepared by solid-state reaction and fast sintering by hot press method. The fast-sintering time can maintain the particle size of the nanometer. Their thermoelectric properties at high temperatures have been studied at 300 - 1000 K. When the usage of a nano-sized precursor leads to decrease electrical resistivity, increase power factor, and would lead to huge growth, respectively. The main effect is observed on thermal conductivity that is lower than sample synthesized with micrometer precursors powder from 0.67 W/mK which became 0.36 W/mK at 973 K. The best ZT value of Ca3Co4O9 reaches 0.51 at 973 K.

Enhanced thermoelectric properties of BaZn2Sb2via a synergistic optimization strategy using co-doped Na and Sr

2016 ◽  
Vol 4 (31) ◽  
pp. 12119-12125 ◽  
Author(s):  
Ruijuan Yan ◽  
Wanyu Lv ◽  
Ke Wang ◽  
Kai Guo ◽  
Xinxin Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Power Factor ◽  
Solid State Reaction ◽  
Solid State Reaction Method ◽  
Optimization Strategy ◽  
Hot Press ◽  
Reaction Method ◽  
Hot Press Sintering ◽  
Co Doped

Polycrystalline samples of Ba1−x−yNaxSryZn2Sb2 (0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.1) were prepared by a solid-state reaction method and hot press sintering with the aim of achieving synergistic optimization of the power factor and thermal conductivity.

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.

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.

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.

scholarly journals Strategy of extra Zr doping on the enhancement of thermoelectric performance for TiZrxNiSn synthesized by a modified solid-state reaction

2021 ◽  
Author(s):  
Jun-Liang Chen ◽  
Hengquan Yang ◽  
Chengyan Liu ◽  
Jisheng Liang ◽  
Lei Miao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Power Factor ◽  
Solid State Reaction ◽  
Lattice Thermal Conductivity ◽  
Phonon Scattering ◽  
Heusler Alloys ◽  
Thermoelectric Performance ◽  
Good Mechanical Property ◽  
Large Power

Abstract Half-Heusler alloys, which possess the advantages of high thermal stability, large power factor and good mechanical property, have been attracted increasing interest in mid-temperature thermoelectric application. In this work, the extra Zr-doped TiZrxNiSn samples were successfully prepared by a modified solid-state reaction followed by spark plasma sintering. It demonstrates that extra Zr doping could not only improve the power factor on account of an increase in Seebeck coefficient but also suppress the lattice thermal conductivity originated from the strengthened phonon scattering by the superlattice nanodomains and the secondary nanoparticles. As a consequence, an increased power factor of 3.29 mW m− 1 K− 2 and a decreased lattice thermal conductivity of 1.74 W m− 1 K− 1 are achieved in TiZr0.015NiSn, leading to a peak ZT as high as 0.88 at 773 K and an average ZT value up to 0.62 in the temperature range of 373 − 773 K. This work gives a guidance for optimizing the thermoelectric performance of TiNiSn-based alloys by modulating the microstructures on the secondary nanophases and superlattice nanodomains.

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.

High Tc Oxide Solid State Reaction Kinetics Via Complex Impedance Spectroscopy

1989 ◽  
Vol 169 ◽  
Author(s):  
E. A. Cooper ◽  
T. O. Mason ◽  
U. Balachandran ◽  
M. L. Kullberg
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Solid State ◽  
Solid State Reaction ◽  
Complex Impedance ◽  
Particle Size Effect ◽  
Large Temperature ◽  
Impedance Spectra ◽  
High Tc ◽  
Solid State Reaction Kinetics

AbstractImpedance spectra (5Hz ‐ 13MHz) were collected during the solid state reaction of Yba2Cu2O6+y from large monosized CuO particles imbedded in a finely divided Y2 O3 /BaCO3 matrix. No particle size effect was observed, but a large temperature effect was observed corresponding to an activation energy of approximately 1.8eV (175kJ/mol) over the range 700‐900°C.

scholarly journals Synthesis and Characterization of Rutile Pigments with Cr and Nb

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Jan Večeřa ◽  
Iveta Šedová ◽  
Petr Mikulášek ◽  
Petra Šulcová
Keyword(s):  
Particle Size ◽  
Solid State ◽  
Particle Size Distribution ◽  
Solid State Reaction ◽  
Organic Matrix ◽  
Synthesis And Characterization ◽  
Visual Color ◽  
Rutile Pigments ◽  
Titanium Compounds

Rutile pigments Ti1-3xCrxNb2xO2±δ (where x=0, 0.05, 0.10, 0.20, 0.30 and 0.50) prepared by solid-state reaction are investigated. Chromium is chromophore (coloring ion) and niobium is counterion (charge-compensating element for electroneutrality). The effect of composition (x), calcination temperature (850, 900, 950, 1000, 1050, 1100 and 1150°C), and starting titanium compounds (anatase TiO2, hydrated anatase paste, TiOSO4·2H2O, and hydrated Na2Ti4O9 paste) on their color properties into organic matrix and particle size distribution was observed. According to the highest chroma C and visual color evaluation, yellow and orange pigments were selected as in color the most interesting. They have concentration x=0.05 or 0.10 and are prepared from anatase TiO2 and TiOSO4·2H2O at temperature ≥1050°C.

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