Preparation of perovskite-type La{sub 1{minus}x}Sr{sub x}MnO{sub 3} films by vapor-phase processes and their electrochemical properties. 2: Effects of doping strontium to LaMnO{sub 3} on the electrode properties
- Kyoto Univ. (Japan)
Complex alternating current impedance and steady-state polarization measurements have been conducted on dense and thin LaMnO{sub 3} and La{sub 0.85}Sr{sub 0.15}MnO{sub 3} film electrodes and porous-sintered LaMnO{sub 3} and La{sub 0.85}Sr{sub 0.15}O{sub 3} electrodes in air at elevated temperatures between 873 and 1,273 K, in order to study the reaction mechanism of oxygen reduction at the La{sub 1{minus}x}Sr{sub x}MnO{sub 3} electrode of a solid oxide fuel cell. By fitting impedance spectra to an appropriate equivalent circuit, the chemical diffusion coefficient of oxygen and interfacial reaction resistance of the LaMnO{sub 3} and La{sub 0.85}Sr{sub 0.15}MnO{sub 3} film electrodes were determined. The chemical diffusion coefficient was scarcely affected by Sr doping, while the interfacial reaction resistance considerably decreased by Sr doping. Steady-state polarization behavior of the porous-sintered La{sub 1{minus}x}Sr{sub x}MnO{sub 3} was dramatically improved by doping Sr, while those of the dense La{sub 1{minus}x}Sr{sub x}MnO{sub 3} film were almost unchanged by Sr doping. These results suggested that the electrochemical reduction of oxygen at the porous La{sub 1{minus}x}Sr{sub x}MnO{sub 3} electrode takes place around the triple phase boundary (TPB), and the reaction rate is controlled by the surface reactions close to the triple phase boundary region.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 653351
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 6 Vol. 145; ISSN 0013-4651; ISSN JESOAN
- Country of Publication:
- United States
- Language:
- English
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