Thermoelectric properties of polycrystalline La{sub 1-x}Sr{sub x}CoO{sub 3}

Journal Article · Fri Nov 14 23:00:00 EST 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.08.017· OSTI ID:21212115

Iwasaki, Kouta ^[1]; Ito, Tsuyoshi ^[1]; Nagasaki, Takanori; Arita, Yuji ^[2]; Yoshino, Masahito ^[1]; Matsui, Tsuneo ^[1]

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1. Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)
2. EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

Thermoelectric properties of polycrystalline La{sub 1-x}Sr{sub x}CoO{sub 3}, where Sr{sup 2+} is substituted in La{sup 3+} site in perovskite-type LaCoO{sub 3}, have been investigated. Sr-doping increases the electrical conductivity ({sigma}) of La{sub 1-x}Sr{sub x}CoO{sub 3}, and also decreases the Seebeck coefficient (S) for 0.01{<=}x{<=}0.40. A Hall coefficient measurement reveals that the increase in electrical conductivity arises from increases in both carrier concentration and the Hall mobility. The decrease in the Seebeck coefficient is caused by a decrease in carrier effective mass as well as increase in carrier concentration. The highest power factor ({sigma}S{sup 2}) is 3.7x10{sup -4} W m{sup -1} K{sup -2} at 250 K for x=0.10. The thermal conductivity ({kappa}) is about 2 W m{sup -1} K{sup -1} at 300 K for 0{<=}x{<=}0.04, and increases for x{>=}0.05 because of an increase in heat transport by conductive carrier. The thermoelectric properties of La{sub 1-x}Sr{sub x}CoO{sub 3} are improved by Sr-doping, and the figure of merit (Z={sigma}S{sup 2} {kappa}{sup -1}) reaches 1.6x10{sup -4} K{sup -1} for x=0.06 at 300 K (ZT=0.048). For heavily Sr-doped samples, the thermoelectric properties diminish mainly because of the decrease in the Seebeck coefficient and the increase in thermal conductivity. - Graphical abstract: Temperature and Sr-doping level dependencies of the power factor of La{sub 1-x}Sr{sub x}CoO{sub 3}.

• OSTI ID: 21212115
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 11 Vol. 181; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
COBALT COMPOUNDS
DOPED MATERIALS
EFFECTIVE MASS
ELECTRIC CONDUCTIVITY
HEAT TRANSFER
LANTHANUM COMPOUNDS
LANTHANUM IONS
MOBILITY
OXIDES
PEROVSKITE
POLYCRYSTALS
POWER FACTOR
STRONTIUM COMPOUNDS
STRONTIUM IONS
THERMAL CONDUCTIVITY
THERMOELECTRIC PROPERTIES