Details
| Original language | English |
|---|---|
| Article number | 2409259 |
| Journal | Advanced functional materials |
| Volume | 35 |
| Issue number | 1 |
| Publication status | Published - 31 Dec 2024 |
Abstract
Misfit-layered calcium cobaltite [Ca2CoO3-δ]0.62[CoO2] is an outstanding p-type semiconducting thermoelectric with strong anisotropic properties. Texture engineering is crucial for enhancing its thermoelectric performance in polycrystalline ceramics. The in-plane orientation of the grains improves the Seebeck coefficient and electrical conductivity, while the multi-scale parallel interfaces scatter phonons and reduce thermal conductivity. Here, a tandem process of spark plasma sintering and edge-free spark plasma texturing is used to produce dense and highly textured calcium cobaltite ceramics. The resulting ceramic shows a high degree of texturization, secondary phases, and enhanced electrical conductivity of 246 S cm−1 together with a strongly improved Seebeck coefficient of 224 µV K−1 at 1073 K. High grain ordering leads to carrier mobility of 0.49 cm2 V−1 s−1, which has a positive effect on both parameters. With a power factor of 12.4 µW cm−1 K−2 at 1073 K in air, previous thermoelectric performances of calcium cobaltite are surpassed, regardless of its form: pristine, doped, or composite. By combining the high power factor with a relatively low thermal conductivity, a remarkable figure-of-merit of 0.49 at 1073 K in air is obtained for the textured polycrystalline ceramic, which reaches 60 % of the figure-of-merit of a calcium cobaltite single crystal.
Keywords
- calcium cobaltites, charge carrier mobility, figure-of-merits, spark plasma sintering, spark plasma texturing, thermoelectrics, transmission electron microscopy
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- Biomaterials
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Chemistry(all)
- Electrochemistry
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In: Advanced functional materials, Vol. 35, No. 1, 2409259, 31.12.2024.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Advances in Texturing and Thermoelectric Properties of a Calcium Cobaltite Ceramic via Combined Spark Plasma Sintering and Spark Plasma Texturing
AU - Kruppa, Katharina
AU - Karlin, Anat
AU - Maor, Itzhak I.
AU - Steinbach, Frank
AU - Shter, Gennady E.
AU - Stobitzer, Dorothea
AU - Xie, Wenjie
AU - Weidenkaff, Anke
AU - Mann-Lahav, Meirav
AU - Grader, Gideon S.
AU - Feldhoff, Armin
N1 - Publisher Copyright: © 2024 The Author(s). Advanced Functional Materials published by Wiley-VCH GmbH.
PY - 2024/12/31
Y1 - 2024/12/31
N2 - Misfit-layered calcium cobaltite [Ca2CoO3-δ]0.62[CoO2] is an outstanding p-type semiconducting thermoelectric with strong anisotropic properties. Texture engineering is crucial for enhancing its thermoelectric performance in polycrystalline ceramics. The in-plane orientation of the grains improves the Seebeck coefficient and electrical conductivity, while the multi-scale parallel interfaces scatter phonons and reduce thermal conductivity. Here, a tandem process of spark plasma sintering and edge-free spark plasma texturing is used to produce dense and highly textured calcium cobaltite ceramics. The resulting ceramic shows a high degree of texturization, secondary phases, and enhanced electrical conductivity of 246 S cm−1 together with a strongly improved Seebeck coefficient of 224 µV K−1 at 1073 K. High grain ordering leads to carrier mobility of 0.49 cm2 V−1 s−1, which has a positive effect on both parameters. With a power factor of 12.4 µW cm−1 K−2 at 1073 K in air, previous thermoelectric performances of calcium cobaltite are surpassed, regardless of its form: pristine, doped, or composite. By combining the high power factor with a relatively low thermal conductivity, a remarkable figure-of-merit of 0.49 at 1073 K in air is obtained for the textured polycrystalline ceramic, which reaches 60 % of the figure-of-merit of a calcium cobaltite single crystal.
AB - Misfit-layered calcium cobaltite [Ca2CoO3-δ]0.62[CoO2] is an outstanding p-type semiconducting thermoelectric with strong anisotropic properties. Texture engineering is crucial for enhancing its thermoelectric performance in polycrystalline ceramics. The in-plane orientation of the grains improves the Seebeck coefficient and electrical conductivity, while the multi-scale parallel interfaces scatter phonons and reduce thermal conductivity. Here, a tandem process of spark plasma sintering and edge-free spark plasma texturing is used to produce dense and highly textured calcium cobaltite ceramics. The resulting ceramic shows a high degree of texturization, secondary phases, and enhanced electrical conductivity of 246 S cm−1 together with a strongly improved Seebeck coefficient of 224 µV K−1 at 1073 K. High grain ordering leads to carrier mobility of 0.49 cm2 V−1 s−1, which has a positive effect on both parameters. With a power factor of 12.4 µW cm−1 K−2 at 1073 K in air, previous thermoelectric performances of calcium cobaltite are surpassed, regardless of its form: pristine, doped, or composite. By combining the high power factor with a relatively low thermal conductivity, a remarkable figure-of-merit of 0.49 at 1073 K in air is obtained for the textured polycrystalline ceramic, which reaches 60 % of the figure-of-merit of a calcium cobaltite single crystal.
KW - calcium cobaltites
KW - charge carrier mobility
KW - figure-of-merits
KW - spark plasma sintering
KW - spark plasma texturing
KW - thermoelectrics
KW - transmission electron microscopy
UR - http://www.scopus.com/inward/record.url?scp=85207130745&partnerID=8YFLogxK
U2 - 10.1002/adfm.202409259
DO - 10.1002/adfm.202409259
M3 - Article
AN - SCOPUS:85207130745
VL - 35
JO - Advanced functional materials
JF - Advanced functional materials
SN - 1616-301X
IS - 1
M1 - 2409259
ER -