Determination of the oxygen permeation flux through La{sub 0.75}Ca{sub 0.25}CrO{sub 3{minus}{delta}} by an electrochemical method

Journal Article · Thu Apr 01 04:00:00 EST 1999 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1391767· OSTI ID:345321

Sakai, Natsuko; Yamaji, Katsuhiko; Horita, Teruhisa; Yokokawa, Harumi ^[1]; Kawada, Tatsuya ^[2]; Dokiya, Masayuki ^[3]; Hiwatashi, Kenichi; Ueno, Akira; Aizawa, Masanobu ^[4]

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1. National Inst. of Materials and Chemical Research, Ibaraki (Japan)
2. Tohoku Univ., Sendai (Japan). Research Inst. for Scientific Measurements
3. Yokohama National Univ. (Japan). Inst. of Environmental Science and Technology
4. TOTO Limited, Kanagawa (Japan). Research and Development Div.

The oxygen permeation flux measured as the oxide ion current density (J{sub O{sup 2{minus}}}) through La{sub 0.75}Ca{sub 0.25}CrO{sub 3{minus}{delta}} was determined at steady state by using an electrochemical method in the p{sub O{sub 2}} range from 10{sup 5} to 10{sup {minus}11} Pa at T = 1273 K. The oxygen vacancy diffusion coefficient (D{sub v}) is estimated to be 1.5 {times} 10{sup {minus}9} m{sup 2}/s in the p{sub O{sub 2}} region from 1 to 10{sup {minus}5} Pa. When p{sub O{sub 2}} is lower than 10{sup {minus}5} Pa, J{sub O{sup 2{minus}}} seems to depend on a surface reaction as the rate-determining step. The contribution of grain-boundary diffusion on permeation was considered in the oxidizing atmosphere. The oxygen permeation current density through a 1 mm thick plate is estimated as 0.03 A/cm{sup 2} in the solid oxide fuel cell operation.

• OSTI ID: 345321
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 4 Vol. 146; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
CALCIUM OXIDES
CHROMIUM OXIDES
CURRENT DENSITY
LANTHANUM OXIDES
OXYGEN
PERMEABILITY
SOLID ELECTROLYTE FUEL CELLS