摘要
以金属硝酸盐、氨水为沉淀剂,采用化学共沉淀法合成了La0.7Sr0.3-xCaxCo0.9Fe0.1O3-"(简称LSCCF,x=0.05,0.10,0.15,0.20)粉料。借助差示扫描量热法-热重分析法(DSC-TG)、X射线衍射法(XRD)和扫描电子显微镜法(SEM)对600℃,800℃,1000℃热处理4h后LSCCF粉料的形成过程、晶体结构和粒度形貌进行了研究。实验结果表明,LSCCF粉料的形成过程分为4个阶段——脱水阶段、分解阶段、LaCoO3基氧化物形成阶段和LSCCF固溶体形成阶段;适宜热处理制度为800℃下保温4h,且制备出的LSCCF粉料为均一的钙钛矿结构。使用直流四极探针法测定了LSCCF样品在空气气氛下的电导率,发现该体系材料在600～800℃范围的电导率都超过了250S·cm-1,其导电机制符合p型小极化子绝热孔隙理论,且能够满足中温固体氧化物燃料电池(ITSOFC)阴极材料的要求。
The powders of La0.7Sr0.3-xCaxCo0.9Fe0.1O3-δ （LSCCF, x = 0.05,0.10,0.15,0.20） were synthesized using a chemical co-precipitation method with La（NO3）3·6 H2O,Sr（NO3）2,Ca （NO3）2· 4 H2O,Co（NO3）2· 6 H2O and Fe （NO3）3 ·9 H2O as precursors and NH4OH as precipitant. The formation process, crystal structure and particle size micrograph of LSCCF powders, calcined at 600℃, 800 ℃ and 1 000 ℃ for 4 h, respecitively, were investigated with DSC-TG,XRD and SEM.The experimental results show that the formation process of LSCCF powders can be divided into four stages： dehydration, decomposition of reactants, formation of LaCoO3 based oxides and formation of LSCCF solid solution, and that the calcined powders at 800 ℃for 4 h are all of single perovskite phase. The electrical conductivity of the sintered samples of LSCCF measured by four-probe DC method is higher than 250 S·cm^-1 from 600 ℃ to 800 ℃ in air. The conduction mechanism for LSCCF powders is attributable to the adiabatic-hopping of p-type small polarons.The synthesized LSCCF powders as cathode material can meet the demands for intermediate temperature solid oxide fuel cells （ITSOFCs）.
出处
《电源技术》
CAS
CSCD
北大核心
2005年第8期496-498,522,共4页
Chinese Journal of Power Sources
基金
国家"863"计划项目(2001AA515080)
瑞典亚洲合作计划项目(DNR6964)
