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Title: Intermediate temperature solid oxide fuel cells using LaGaO{sub 3} electrolyte. II. Improvement of oxide ion conductivity and power density by doping Fe for Ga site of LaGaO{sub 3}

Abstract

Effects of small amounts of Fe doping for Ga site in LaGaO{sub 3}-based oxide on oxide ion conductivity is investigated in this study. It is found that doping a small amount of Fe is effective for improving the oxide ion conductivity in La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3} (LSGM). The highest oxide ion conductivity was exhibited at x = 0.03 in La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2{minus}x}Fe{sub x}O{sub 3} among the Fe-doped samples. Electron spin resonance (ESR) measurements suggest that Fe is trivalent in LaGaO{sub 3} lattice. The application of the Fe-doped LaGaO{sub 3}-based oxide for the electrolyte of solid oxide fuel cell was further investigated. Power density of the solid oxide fuel cell was increased by using Fe-doped LSGM for electrolyte. This can be explained by the decrease in electrical resistance loss by improving the oxide ion conductivity. A maximum power density close to 700 mW/cm{sup 2} was obtained at 1,073 K on the cell using 0.5 mm thick La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.17}Fe{sub 0.03}O{sub 3} (LSGMF) and O{sub 2} as the electrolyte and the oxidant, respectively. Therefore, close to the theoretical open-circuit potential was exhibited by the LSGMF cell. On the other hand, the power density was slightly smallermore » than that of the cell using Co-doped LSGM as electrolyte, especially, at temperatures lower than 973 K. This may result from the large activation energy for ion conductivity. However, the power density of the LSGMF cell was higher than that of the LSGM cell. Therefore, LSGM doped with a small amount of Fe is a promising electrolyte similar to Co-doped LSGM for the intermediate solid oxide fuel cell.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Oita Univ. (JP)
OSTI Identifier:
20075607
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 147; Journal Issue: 4; Other Information: PBD: Apr 2000; Journal ID: ISSN 0013-4651
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; SOLID OXIDE FUEL CELLS; GALLIUM OXIDES; LANTHANUM OXIDES; DOPED MATERIALS; IRON; ELECTROLYTES

Citation Formats

Ishihara, Tatsumi, Shibayama, Takaaki, Honda, Miho, Nishiguchi, Hiroyasu, and Takita, Yusaku. Intermediate temperature solid oxide fuel cells using LaGaO{sub 3} electrolyte. II. Improvement of oxide ion conductivity and power density by doping Fe for Ga site of LaGaO{sub 3}. United States: N. p., 2000. Web. doi:10.1149/1.1393358.
Ishihara, Tatsumi, Shibayama, Takaaki, Honda, Miho, Nishiguchi, Hiroyasu, & Takita, Yusaku. Intermediate temperature solid oxide fuel cells using LaGaO{sub 3} electrolyte. II. Improvement of oxide ion conductivity and power density by doping Fe for Ga site of LaGaO{sub 3}. United States. doi:10.1149/1.1393358.
Ishihara, Tatsumi, Shibayama, Takaaki, Honda, Miho, Nishiguchi, Hiroyasu, and Takita, Yusaku. Sat . "Intermediate temperature solid oxide fuel cells using LaGaO{sub 3} electrolyte. II. Improvement of oxide ion conductivity and power density by doping Fe for Ga site of LaGaO{sub 3}". United States. doi:10.1149/1.1393358.
@article{osti_20075607,
title = {Intermediate temperature solid oxide fuel cells using LaGaO{sub 3} electrolyte. II. Improvement of oxide ion conductivity and power density by doping Fe for Ga site of LaGaO{sub 3}},
author = {Ishihara, Tatsumi and Shibayama, Takaaki and Honda, Miho and Nishiguchi, Hiroyasu and Takita, Yusaku},
abstractNote = {Effects of small amounts of Fe doping for Ga site in LaGaO{sub 3}-based oxide on oxide ion conductivity is investigated in this study. It is found that doping a small amount of Fe is effective for improving the oxide ion conductivity in La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2}O{sub 3} (LSGM). The highest oxide ion conductivity was exhibited at x = 0.03 in La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.2{minus}x}Fe{sub x}O{sub 3} among the Fe-doped samples. Electron spin resonance (ESR) measurements suggest that Fe is trivalent in LaGaO{sub 3} lattice. The application of the Fe-doped LaGaO{sub 3}-based oxide for the electrolyte of solid oxide fuel cell was further investigated. Power density of the solid oxide fuel cell was increased by using Fe-doped LSGM for electrolyte. This can be explained by the decrease in electrical resistance loss by improving the oxide ion conductivity. A maximum power density close to 700 mW/cm{sup 2} was obtained at 1,073 K on the cell using 0.5 mm thick La{sub 0.8}Sr{sub 0.2}Ga{sub 0.8}Mg{sub 0.17}Fe{sub 0.03}O{sub 3} (LSGMF) and O{sub 2} as the electrolyte and the oxidant, respectively. Therefore, close to the theoretical open-circuit potential was exhibited by the LSGMF cell. On the other hand, the power density was slightly smaller than that of the cell using Co-doped LSGM as electrolyte, especially, at temperatures lower than 973 K. This may result from the large activation energy for ion conductivity. However, the power density of the LSGMF cell was higher than that of the LSGM cell. Therefore, LSGM doped with a small amount of Fe is a promising electrolyte similar to Co-doped LSGM for the intermediate solid oxide fuel cell.},
doi = {10.1149/1.1393358},
journal = {Journal of the Electrochemical Society},
issn = {0013-4651},
number = 4,
volume = 147,
place = {United States},
year = {2000},
month = {4}
}