摘要
用柠檬酸-硝酸盐水系溶液为前驱体合成了具有钙钛矿结构的中温电解质La_(0.8)Sr_(0.2)Ga_(0.85)Mg_(0.15)O_(3-s-δ)(LSGM)。用DTA-TGA和X射线衍射仪分析了LSGM材料中钙钛矿相的形成过程,用热膨胀仪和交流复阻抗谱研究了样品的烧结、热膨胀和电学性能。研究结果表明:用柠檬酸-硝酸盐溶液制备LSGM所得到的非晶产物在800℃时开始形成钙钛矿相,1400℃烧结6 h已经完全转变成稳定钙钛矿相,LSGM样品在1450℃烧结6 h,相对密度已经达到98％。1450℃烧结6 h的LSGM样品阻抗谱研究表明:与固相法制备的LSGM相比,用柠檬酸-硝酸盐溶液合成的LSGM晶界电阻和杂相电阻都很小,不影响样品的电导。表明用湿化学法合成LSGM有利于提高纯度,改善导电性能。850℃时样品的电导率为6.0×10^(-2)S/cm,900℃时单电池的最大输出功率密度为12.2 mW/cm^2,短路电流密度达刭55.2 mA/cm^2。
The intermediate-temperature solid electrolyte with perovskite-type La0.8Sr0.2Ga0.85Mg0.15O3-δ(LSGM) was synthe-sized using citric acid - nitrate aqueous solution as precursors. The forming process of the perovskite phase in LSGM material was analyzed by means of DTA - TGA and X-ray diffractometer. The sintering, thermal expansion and electrical properties of the samples were studied by dilatometer and a. c. impedance spectra. The results show that the formation of a perovskite phase from the amorphous products obtained by citric acid - nitrate precursors begins at calcining temperature of 800℃ and the stable perovskite phase is formed completely after sintering at temperature 1400℃for 6 h. A relative density of 98% is obtained when the LSGM sample was sintered at 1450℃ for 6 h. Impedance spectra of samples sintered at 1450℃ for 6 h indicate that the grain boundary and impurity resistances of the LSGM synthesized by citric acid - nitrate precursors are smaller compared to the one made by solid-state method, and there is no effects on the conduction of samples. It shows that the wet-chemistry method of synthesizing LSGM is advantageous to enhance purity and improve electrical properties of the material. The conduc-tivity of samples is 6. 0×10-2 S/cm at 850℃. At 900℃ , the maximum power density and short current density for the single cell is 12. 2 mW/cm2and 55. 2 mA/cm2, respectively.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2003年第9期907-912,共6页
Journal of The Chinese Ceramic Society
基金
吉林省科技厅(20000322)资助项目
关键词
掺杂镓酸镧
中温电解质
电学性能
固体氧化物燃料电池
doped lanthanum gallate
intermediate-temperature electrolyte
electrical properties
solid oxide fuel cell
