科研之友
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摘要
Solid oxide fuel cells with the conventional configuration of Ni-ytttria-stabilized zirconia (Ni-YSZ)vertical bar YSZ vertical bar(La, Sr)MnO(3 +/-delta) (LSM) have been reported to exhibit performance improvement in the initial discharge operation, which is attributed to the activation of LSM. In this study, the time course of potential for LSM was monitored under cathodic polarization to precisely analyze this enhancement. A characteristic phenomenon of potential oscillation was found during the constant current loading. Regardless of electrolyte materials and LSM composition, the potential was oscillated with a frequency of ca. 0.67 Hz soon after current passing. The potential oscillation appeared under the following conditions: (i) at low partial pressure of oxygen, (ii) at high cathodic current loading, and (iii) for an LSM electrode with low porosity. The amplitude of oscillation reduced with the elapsed time of cathodic polarization and then disappeared. The microscopic observation revealed that the structural change in the LSM electrode after cathodic polarization is responsible for the disappearance of potential oscillation. These findings suggest that the potential oscillation originates in the mass-transfer limitation, oxygen diffusion, and densified electrode.
- 出版日期2010
