Synthesis And Properties Analysis On The Intermediate-temperature Sofc(solid Oxide Fuel Cell)'s Electrolyte

The perovskite-type La0.8Sr0.2Ga1-yMgyO3-δwere synthesized by the EDTA complexing Sol-Gel method. The Archimedes, TG-DTA, XRD and two-probe ac impedance technique were used to analyze density, the phase transformation process, the thermal and electrical properties. The synthesis craft of materials was investigated by these ways. The results reveal that quantity of EDTA, pH of solution and temperature of forming Gel are the important factors to affect synthesis of colloid. The sintering technology generated significant influence on the properties of the La0.8Sr0.2Ga1-yMgyO3-δsamples. The optimum synthesis parameters to prepare La0.8Sr0.2Ga1-yMgyO3-δelectrolyte were ascertained.The ionic conductivity of La0.8Sr0.2Ga1-yMgyO3-δelectrolyte was investigated using ac impedance technique. The research showed that the conductivity of all samples enhanced with the temperature raising. At an identical measuring temperature, the electrical conductivity of La0.8Sr0.2Ga1-yMgyO3-δchanged little over y from 0.1 to 0.2. Then it decreased gradually between 500℃and 800℃as y greater than 0.2. The conductivity of La0.8Sr0.2Ga0.8Mg0.2O3-δis 3.62×10-2S/cm as maximum at 800℃. The solid solubility limit of Mg in La0.8Sr0.2Ga1-yMgyO3-δelectrolyte is about 40﹪at the substitution site.To increase the conductivity of the electrolyte more, The perovskite-type Fe-doped La0.8Sr0.2Ga0.8Mg0.15Fe0.05O3-δwere synthesized by the EDTA complexing Sol-Gel method. Their Properties were compared by the analysis of BET, impedance spectra, conductivity, density, XRD and FT-IR. When sintered at 800℃, the conductivity of the La0.8Sr0.2Ga0.8Mg0.15Fe0.05O3-δwas 5.21×10-2S/cm as that of La0.8Sr0.2Ga0.8Mg0.2O3-δwas 3.62×10-2S/cm. Research showed that Fe doping increased the fractional density from 95.13℅ to 97.93℅. So the Fe-doped La0.8Sr0.2Ga0.8Mg0.15Fe0.05O3-δis more applicable for IT-SOFC.