复合掺杂氧化物La_(0.5)Sr_(0.5)CoO_(2.91)的性能和稳定性  

Characterization and Stability of La_(0.5)Sr_(0.5)CoO_(2.91) Perovskite-Type Oxide

作　　者：李彦[1] 余春江[1] 骆仲泱 许祝安[2] 岑可法[1] 

机构地区：[1]浙江大学热能工程研究所能源清洁利用国家重点实验室 [2]浙江大学理学院物理系,浙江杭州310027

出　　处：《中国稀土学报》2006年第4期442-446,共5页Journal of the Chinese Society of Rare Earths

摘　　要：采用固相反应法和柠檬酸-硝酸盐溶胶-凝胶低温自蔓延燃烧法（简称柠檬酸法）合成了La0.5Sr0.5CoO2．91（LSC）复合氧化物。借助XRD和SEM对不同制备方法合成粉体的晶体结构和晶粒形貌进行了研究。结果表明：固相反应法可制得均一钙钛矿结构的LSC氧化物，柠檬酸法除制得LSC氧化物外，还有LaSrCoO4相的生成。柠檬酸-硝酸盐溶胶-凝胶低温自蔓延燃烧法合成粉体的粒度相对较小。为研究以Ce0．9Gd0.1O1．95（GDC）为电解质的固体氧化物燃料电池阴极材料的性能，将LSC粉体与GDC粉体按6：4（质量比）制备了固体氧化物燃料电池（SOFC）的阴极片。在空气气氛下使用直流四探针法研究了烧结样品300～800℃的电导率，发现由柠檬酸法得到粉体制备的阴极片的电导率值较高。将制备的样品置于马弗炉中800℃条件下烧结800h，比较失效前后电导率的变化情况，并借助XRD，SEM等测试手段分析样品电导率变化的原因。分析发现，失效后两种样品的电导率值都有所降低，且样品中都有新相生成，晶体形貌有较大的变化。Compositely doped oxide La0.5Sr0.5CoO2.91 （LSC） was synthesized using solid state reaction and citric acid-nitrate low temperature self-propagating combustion methods. The crystal structure and the particle size micrograph different methods were of LSC powders synthesized by investigated with XRD and SEM. The experimental results show that the single perovskite phase of LSC can be synthesized by solid state reaction method, but LaSrCoO4 phase appears in LSC powder synthesized by citric acid-nitrate low temperature self-propagating combustion method. The LSC particle by citric acid-nitrate low temperature selfpropagating combustion method has smaller size. To analyze the character of cathode material based on Ce0.9Gd0.1O1.95 （GDC） electrolyte, two types of cathode wafers were fabricated with the two kinds of LSC and GDC powders at the mass rate of 6：4, respectively. The electrical conductivity of the sintered samples was measured by four probe DC method from 300 to 800℃. The cathode with LSC particle by citric acidnitrate low temperature self-propagating combustion method has higher electrical conductivity. In order to investigate the stability, the two samples were put into the muffle furnace to heat up in air at 800℃ for 800 h. To analysis the reason for reduced electrical conductivity, the crystal structure and the particle micrograph of the cathode wafers before and after an exposure were investigated with XRD and SEM. The result shows that new crystal structure appears in both the two kinds of cathode wafers and crystal micrographs change a lot

关 键 词：固体氧化物燃料电池 La0.5Sr0.5CoO2.91 制备方法 阴极 电导率 稳定性 稀土 

分 类 号：TM911[电气工程—电力电子与电力传动]