Synthesis and Thermoelectric Properties of Ceramics Based on Bi2Ca2Co1.7O y Oxide

Klyndyuk, A. I.; Krasutskaya, N. S.; Чижова, Е. А.

doi:10.1134/s1087659618020086

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…The elevated values of the Seebeck coefficient for the Ca 3 Co 4 O 9 + δ + x wt % Cu composites sintered at 1373 K and the observed anomalous dependence S = f(T) are probably caused by the Co 3 O 4 phase, which is contained in them in significant amounts and is characterized by high S values and by its anomalous temperature dependence [29].…”

Section: Resultsmentioning

confidence: 95%

“…4a,4d,4g,4j; Table 1). The electrical conductivity of the Ca 3 Co 4 O 9 + δ + x wt % Cu samples sintered at 1173 K, and also the Ca 3 Co 4 O 9 + δ + 3 wt % Cu material sintered at 1273 K (with the maximum electrical conductivity σ ⊥,1100 = 82.2 S/cm (Table 1)) is higher than that of the Ca 3 Co 4 O 9 + δ matrix phase owing to the [13,29]; the electrical conductivity is lowest for the Ca 3 Co 4 O 9 + δ + x wt % Cu ceramics sintered at 1373 K (Fig. 4g), which contains the maximum amount of these phases.…”

Section: Resultsmentioning

confidence: 99%

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Effect of the Addition of Copper Particles on the Thermoelectric Properties of the Ca3Co4O9 + δ Ceramics Produced by Two-Step Sintering

Klyndyuk

Чижова

Latypov

et al. 2022

Russ. J. Inorg. Chem.

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Composite thermoelectric materials based on layered calcium cobaltite Ca3Co4O9 + δ doped with copper particles were synthesized by two-step sintering, and their microstructure, and electrotransport and thermoelectric properties were studied. It was determined that the introduction of copper particles into the ceramics improves their sinterability at moderate sintering temperatures (Tsint ≤ 1273 K), leading to a decrease in the porosity of the samples and an increase in their electrical conductivity and power factor, whereas the oxidation of copper to less conductive copper(II) oxide significantly decreases the electrical conductivity and power factor of the ceramics sintered at elevated temperatures (Tsint ≥ 1373 K). The power factor is maximum for the Ca3Co4O9 + δ + 3 wt % Cu ceramic sintered at 1273 K (335 μW/(m K2) at a temperature of 1100 K), which is by a factor of 2.3 higher than the power factor of the base material Ca3Co4O9 + δ with the same thermal history (145 μW/(m K2) at 1100 K) and more than 3 times higher than the power factor of the Ca3Co4O9+δ ceramic synthesized by the conventional solid-phase method.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

Effect of the Addition of Copper Particles on the Thermoelectric Properties of the Ca3Co4O9 + δ Ceramics Produced by Two-Step Sintering

Klyndyuk

Чижова

Latypov

et al. 2022

Russ. J. Inorg. Chem.

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“…Powders of Na 2 CO 3 (99%), Co 3 O 4 (99%), Cr 2 O 3 (99%), NiO (99.99%), WO 3 (99.99%), and Bi 2 O 3 (99.99%) were mixed in proportions of Na:Co:M = 0.6:0.9:0.1. The excess amount of Na 2 CO 3 was introduced in the batch to compensate for the losses of the Na 2 O in the ceramics due to its high-temperature treatment and to obtain the samples of the following composition Na 0.55 (Co,M)O 2 (M = Cr, Ni, Zn, W, and Bi) [21,38]. Weighed batches were mixed with C 2 H 5 OH (~3-5 wt.%) and then milled in a PM 100 Retsch planetary mill (material of beakers and grinding balls is ZrO 2 ) for 90 min at 300 rpm.…”

Section: Methodsmentioning

confidence: 99%

“…x O 2 ).The average oxidation degree of cobalt and real sodium content in the obtained ceramic materials were determined by means of iodiometric [38] and reverse potentiometric titration [41] (see Supplementary Information).…”

Section: Methodsmentioning

confidence: 99%

Enhanced Thermoelectric Performance of Na0.55CoO2 Ceramics Doped by Transition and Heavy Metal Oxides

Krasutskaya,

Klyndyuk,

Evseeva

et al. 2024

Solids

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Using the solid-state reactions method Na0.55(Co,M)O2 (M = Cr, Ni, Zn, W, and Bi) ceramics were prepared and their crystal structure, microstructure, electrophysical, thermophysical, and thermoelectric properties were studied. Doping of Na0.55CoO2 by transition or heavy metal oxides led to the increase in the grain size of ceramics, a decrease in electrical resistivity and thermal diffusivity values, and a sharp increase in the Seebeck coefficient, which resulted in essential enhancement of their thermoelectric properties. The largest power factor (1.04 mW/(m·K2) at 1073 K) and figure of merit (0.702 at 1073 K) among the studied samples possessed the Na0.55Co0.9Bi0.1O2 compound, which also demonstrated the highest values of the Seebeck coefficient (666 μV/K at 1073 K). The obtained results show that the doping of layered sodium cobaltite by different metal oxides allows for improving its stability, microstructure, and functional properties, which proves the effectiveness of the doping strategy for developing new thermoelectric oxides with enhanced thermoelectric performance.

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“…with attractive TE properties [7][8][9][10][11][12][13][14]. Ca 3 Co 4 O 9 crystal structure is formed by two layers, CdI 2 -type CoO 2 and rock-salt-type (RS), with common a-and c-axis lattice parameters and  angles but different b-axis length, causing a misfit along the b-direction [15].…”

Section: Introductionmentioning

confidence: 99%

High-Temperature Stability of Hot-Pressed Sr-Doped Ca3Co4O9

Madre

Urrutibeascoa

Garcia³

et al. 2018

Journal of Elec Materi

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Ca 2.93 Sr 0.07 Co 4 O 9 bulk textured samples have been successfully prepared by hot uniaxial pressing, followed by a thermal treatment at 800ºC under air between 0 and 1532 h. The microstructural, thermoelectric and mechanical properties as well as density of all the samples were evaluated as a function of the thermal treatment length. Scanning electron microscope characterization has shown that samples are mainly composed by Sr-doped Ca 3 Co 4 O 9 thermoelectric (TE) phase, accompanied by minor amounts of Sr-free Ca 3 Co 2 O 6 secondary phase. After an initial decrease of density after the first aging treatment, it remains practically constant for longer times. This behaviour is reflected in the mechanical properties, which slightly decrease after 12 h thermal treatment, when compared with the as-hot pressed ones, and remain practically constant for larger times. However, TE properties are not affected by the aging process, and are within the typical errors, independently of the aging time. Moreover, power factor values at 850ºC are between the highest obtained so far in this kind of materials (> 0.60mW/K 2 m) 2

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Synthesis and Thermoelectric Properties of Ceramics Based on Bi2Ca2Co1.7O y Oxide

Cited by 7 publications

References 24 publications

Effect of the Addition of Copper Particles on the Thermoelectric Properties of the Ca3Co4O9 + δ Ceramics Produced by Two-Step Sintering

Effect of the Addition of Copper Particles on the Thermoelectric Properties of the Ca3Co4O9 + δ Ceramics Produced by Two-Step Sintering

Enhanced Thermoelectric Performance of Na0.55CoO2 Ceramics Doped by Transition and Heavy Metal Oxides

High-Temperature Stability of Hot-Pressed Sr-Doped Ca3Co4O9

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