Fast preparation route to high-performances textured Sr-doped Ca3Co4O9 thermoelectric materials through precursor powder modification

Torres, Miguel; Garcia, Gustavo; Urrutibeascoa, I.; Madre, M. A.; Díez, J. C.; Sotelo, A.

doi:10.1007/s40843-018-9339-1

Cited by 21 publications

(10 citation statements)

References 33 publications

(50 reference statements)

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“…Despite similar semiconducting behavior of both types of samples, in agreement with previous reports, the values are much lower for textured samples than for sintered ones. This decrease can be explained by the higher density and better grain alignment obtained in hot‐pressed specimens which aligns, at the same time, the conducting planes of Ca 3 Co 4 O 9 phase . The minimum resistivity values (8.7 mΩ·cm) have been obtained at 675°C in textured samples, which is much lower than the measured at 800°C in bulk sintered materials (40 mΩ·cm) .…”

Section: Resultsmentioning

confidence: 77%

Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Mora

Amaveda

Torres

et al. 2019

Int J Applied Ceramic Tech

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Sr-doped Ca 3 Co 4 O 9 thermoelectric thick films have been prepared by dip-coating technique, followed by sintering and hot uniaxial pressing. XRD patterns are very similar in both types of samples, with only differences in the relative intensity of peaks, pointing out to a better grain orientation in hot-pressed films. Moreover, SEM observation showed a drastic decrease in the hot-pressed films thickness. Electrical resistivity is decreased in textured materials due to the higher grain orientation and density, confirmed through Hall measurements. On the other hand, Seebeck coefficient is maintained practically unchanged. Power factor at 800°C is much higher in textured materials (0.44 mW/K 2 m) than determined in sintered films (0.30 mW/ K 2 m), and in the order of the best typically reported in the literature (0.43 mW/K 2 m). K E Y W O R D S ceramics, electrical properties, microstructure, oxides, thermoelectrics, thick films How to cite this article: Mora M, Amaveda H, Torres MA, Madre MA, Marinel S, Sotelo A. Enhancement of electrical conductivity of Ca 2.93 Sr 0.07 Co 4 O 9 thick films via hot uniaxial pressing. Int J Appl Ceram Technol.

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Section: Resultsmentioning

confidence: 77%

Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Mora

Amaveda

Torres

et al. 2019

Int J Applied Ceramic Tech

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“…In addition, the double Ag 3d peaks located at 373.8 and 367.8 eV, respectively, suggesting that Ag + and the secondary phase Ag were incorporated into CCO composite ceramics. 12 Heikes et al believed that the enhancement of thermopower originated from the spin entropy of charge carriers, which could be expressed by the modified Heikes formula 10 :…”

Section: Resultsmentioning

confidence: 99%

“…Ca 3 Co 4 O 9 (abbreviated as CCO) is a potential p-type thermoelectric material, which presents the high thermoelectric properties for oxides ceramics, and the ZT of 0.83 for the single crystal is obtained at 973 K. 12 There are some strategies to optimize the thermoelectric performance of CCO ceramics, such as the modification of element doping and the secondary phase composite. 13,14 Especially, the vacancy compensation mechanism can be adopted to compensate the nonequivalent ion substitution when the high valence ions replace to Ca 2+ sites in the crystal lattice.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and thermoelectric performance of La‐doped (Ca_0.9Ag_0.1)₃Co₄O₉/nano‐sized Ag composite ceramics

Shi

Zhang

et al. 2019

Int J Ceramic Engine & Sci

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Ca 0.9-x Ag 0.1 La x ) 3 Co 4 O 9 /nano-sized Ag thermoelectric composite ceramics were fabricated by solid-state reaction method. The influences of La 3+ dopants on the microstructure, band gaps, and thermoelectric properties were investigated. X-ray photoelectron spectroscopy fitting results showed that the reduction of oxygen vacancy and the increment of trivalent cobalt concentration could significantly improve thermoelectric performance. With the increasing of La 3+ dopants level, the band gaps of samples enlarged. Electrical resistivity decreased from 21.3 to 17.2 mΩ·cm, while Seebeck coefficient increased from 113.3 to 182.3 μV/K. Furthermore, the peak ZT value of 0.18 was obtained at 1073 K for the x = 0.03 sample, resulting from the lower thermal conductivity of 1.05 W/(m·K). The obtained results suggest that the La 3+ substitution, oxygen vacancy, and Ag inclusions can dramatically improve the thermoelectric performance of Ca 3 Co 4 O 9 composites. K E Y W O R D S (Ca 0.9-x Ag 0.1 La x ) 3 Co 4 O 9 , electrical conductivity, nano-sized Ag, thermoelectric composites 8 | SHI et al.

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“…Several groups applied hot-pressing (or sinter-forging, respectively) with pressures from 5 MPa to 50 MPa. 5,10,19 The Co349 specimens were highly textured and nearly fully dense. With a pressure of 30 MPa, Kenfaui et al 9 reached σ(900K) = 8 • σ ref .…”

Section: Introductionmentioning

confidence: 99%

Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite

et al. 2020

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Fast preparation route to high-performances textured Sr-doped Ca3Co4O9 thermoelectric materials through precursor powder modification

Cited by 21 publications

References 33 publications

Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Microstructure and thermoelectric performance of La‐doped (Ca_0.9Ag_0.1)₃Co₄O₉/nano‐sized Ag composite ceramics

Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite

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Fast preparation route to high-performances textured Sr-doped Ca3Co4O9 thermoelectric materials through precursor powder modification

Cited by 21 publications

References 33 publications

Enhancement of electrical conductivity of Ca2.93Sr0.07Co4O9 thick films via hot uniaxial pressing

Enhancement of electrical conductivity of Ca2.93Sr0.07Co4O9 thick films via hot uniaxial pressing

Microstructure and thermoelectric performance of La‐doped (Ca0.9Ag0.1)3Co4O9/nano‐sized Ag composite ceramics

Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite

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Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Enhancement of electrical conductivity of Ca_2.93Sr_0.07Co₄O₉ thick films via hot uniaxial pressing

Microstructure and thermoelectric performance of La‐doped (Ca_0.9Ag_0.1)₃Co₄O₉/nano‐sized Ag composite ceramics