科研之友
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摘要
Crystal structure, thermal expansion coefficient; electrical conductivity and cathodic polarization of compositions in the system Sm0.5Sr0.5Co1-xFexO3-delta with 0 <= x <= 0.9 were studied as a function of Co/Fe ratio and temperature in air. Two phases, an orthorhombic symmetry for 0 <= x <= 0.4 and a cubic symmetry for 0.5 <= x <= 0.9, were observed in samples Of Sm0.5Sr0.5Co1-xFe3-delta at room temperature. The adjustment of thermal expansion coefficient (TEC) to electrolyte, which is one of the main problems of SSC, could be achieved to lower TEC values with more Fe substitution. High electrical conductivity above 100 S center dot cm(-1) at 800 degrees C was obtained for all specimens, so they could be good conductors as cathodes of IT-SOFC. The polarization behavior of SSCF as a function of Fe content was evaluated by means of AC impedance using LSGM electrolyte. It is found that the Area Specific Resistance (ASR) of SSCF increases as the amount of substitution of Fe for Co increases. When the amount of Fe reaches to 0.4, the highest ASR is obtained and then the resistance starts decreasing. The electrode with a composition of Su(0.5)Sr(0.5)Co(0.2)Fe(0.8)O(3-delta) shows high catalytic activity for oxygen reduction operating at temperature ranging from 700 to 800 degrees C.
- 出版日期2006-11
- 单位上海交通大学; 金属基复合材料国家重点实验室
