Intermediate temperature solid oxide fuel cells using a new LaGaO{sub 3} based oxide ion conductor. 1: Doped SmCoO{sub 3} as a new cathode material

Journal Article · Tue Sep 01 04:00:00 EDT 1998 · Journal of the Electrochemical Society

DOI:https://doi.org/10.1149/1.1838783· OSTI ID:659123

Ishihara, Tatsumi; Honda, Miho; Shibayama, Takaaki; Minami, Hiroaki; Nishiguchi, Hiroyasu; Takita, Yusaku ^[1]

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1. Oita Univ. (Japan)

LaGaO{sub 3}-based perovskite oxides doped with Sr and Mg exhibit high ionic conductivity over a wide range of oxygen partial pressure. In this study, the stability of LaGaO{sub 3}-based oxide was investigated. The LaGaO{sub 3}-based oxide was found to be very stable in reducing, oxidizing, and CO{sub 2} atmospheres. Solid oxide fuel cells (SOFCs) using LaGaO{sub 3}-based perovskite-type oxide as the electrolyte were studied for use in intermediate-temperature SOFCs. The power-generation characteristics of cells were strongly affected by the electrodes. Both Ni and LnCoO{sub 3} (Ln:rare earth) were suitable for use as anode and cathode, respectively. Rare-earth cations in the Ln site of the Co-based perovskite cathode also had a significant effect on the power-generation characteristics. In particular, a high power density could be attained in the temperature range 973--1,273 K by using a doped SmCoO{sub 3} for the cathode. Among the examined alkaline earth cations, Sr-doped SmCoO{sub 3} exhibits the smallest cathodic overpotential resulting in the highest power density. The electrical conductivity of SmCoO{sub 3} increased with increasing Sr doped into the Sm site and attained a maximum at Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}. The cathodic overpotential and internal resistance of the cell exhibited almost the opposite dependence on the amount of doped Sr. Consequently, the power density of the cell was a maximum when Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3} was used as the cathode. For this cell, the maximum power density was as high as 0.58 W/cm{sup 2} at 1,073 K, even though a 0.5 mm thick electrolyte was used. This study revealed that a LaGaO{sub 3}-based oxide for electrolyte and a SmCoO{sub 3}-based oxide for the cathode are promising components for SOFCs operating at intermediate temperature.

• Sponsoring Organization: USDOE
• OSTI ID: 659123
• Journal Information: Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 9 Vol. 145; ISSN 0013-4651; ISSN JESOAN
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
CATHODES
COBALT OXIDES
DOPED MATERIALS
GALLIUM OXIDES
IONIC CONDUCTIVITY
LANTHANUM OXIDES
POWER DENSITY
SAMARIUM OXIDES
SOLID ELECTROLYTE FUEL CELLS