Lanthanum alkaline-earth manganites as a cathode material in high-temperature solid oxide fuel cells
The effect of RE (RE = Ce and Pr) doping LaMnO{sub 3} perovskite on crystallographic properties, phase relationships, conductivity, thermal expansion, sintering, and reaction with Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} electrolyte is presented. La{sub 1{minus}x}Re{sub x}MnO{sub 3} showed a single perovskite phase in the region 0 {le} x {le} 0.05 for Ce substitution and over the entire composition range of Pr content. No effect of RE doping of LaMnO{sub 3} on conductivity was observed. A decrease in thermal expansion coefficients of LaMnO{sub 3} accompanied RE doping. Ce doping of LaMnO{sub 3} increased its morphological stability and suppressed its reaction with the electrolyte. Ln{sub 1{minus}x}AE{sub x}MnO{sub 3} (Ln: lanthanum concentration with La, Ce, and Pr, AE = Sr, Ca) materials were examined as cathodes in solid oxide fuel cells. X-ray diffraction analysis indicated that Ln{sub 1{minus}x}AE{sub x}MnO{sub 3} (0 {le} x {le} 0.3) showed a single perovskite phase. Conductivities of these oxides increased with AE content and ranged from 80 to 200 S/cm at 1,000 C in air, and thermal expansion coefficients ranged from 9.5 to 11.6 x 10{sup {minus}6}/C. Ln{sub 1{minus}x}AE{sub x}MnO{sub 3} showed less reactivity with the electrolyte compared with La{sub 1{minus}x}AE{sub x}MnO{sub 3}. The cathodic polarization of the (Ln{sub 0.8}Sr{sub 0.2}){sub 0.95}MnO{sub 3} at 1,000 C was 60 mV at 500 mA/cm{sup 2} in air.
- Research Organization:
- Electric Power Industry, Yokosuka, Kanagawa (JP)
- OSTI ID:
- 20003937
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 11 Vol. 146; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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