| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系研究所 === 99 === This study was to develop La1-xSrxGa1-yMgyO3-δ solid electrolytes with high ionic conductivity for intermediate temperature SOFC (Solid Oxide Fuel Cell).The perovskite solid solution formed by the substitution of La and Ga by Sr and Mg had a superior oxide ion conuctivity at intermediate temperature of 600oC ~ 800oC. The LSGM ceramics had studied correlations between the crystal structures and oxide ion conduction properties of LaGaO3-based compound systems by XRD, SEM, TEM, Raman and conductivity. The crystal structure was changed from the orthorhombic to the rhombohedral with dopimg Sr and Mg was odserved. The second phase SrLaGa3O7 was identified by XRD and EDS. The extra aman bands at 674 cm-1, 738 cm-1 were observed, probably due to oxygen vacancy inducing by doping. The average grain size will increase with increasing by Sr and Mg site dopant content. The ionic conductivity of LSGM was enhanced with increase of both the Sr and Mg doped. When the total dopant concentration was more than 0.35 mol, the conductivity was higher than 0.16 S/cm. The lamellar-like microstructure was observed in LSGM1010, LSGM1020 specimens, and decreased with increasing dopant content.
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