【摘要】 采用X射线衍射、扫描电镜及电化学方法考察了固体氧化物燃料电池钐锶钴(Sm0.5Sr0.5CoO3-δ,SSC)阴极烧结温度和时间对镧锶镓镁(La0.9Sr0.1Ga0.8Mg0.2O3-δ,LSGM)电解质的导电行为和电解质/阴极界面电化学性质的影响.结果表明,当SSC阴极的烧结温度由1173K升高到1323K时,LSGM/SSC界面形成了LaSrGaO4和LaSrGa3O7杂相;当烧结温度升高到1373K时,还形成了高电子电导率的La-Sr-Co-O复合化合物.Co元素的扩散导致LSGM电解质电子电导率升高,氧离子迁移数和电池开路电压降低.延长SSC阴极烧结时间,LSGM电解质的欧姆电阻增大,电解质氧离子迁移数和电池的开路电压降低,这是由于延长SSC烧结时间加剧了LSGM/SSC界面上高阻抗相LaSrGaO4和LaSrGa3O7的生成.阴极中大量Co元素的扩散改变了LSGM电解质内部组成与结构.更多还原

【Abstract】 The effect of elemental diffusion from strontium-doped samarium cobaltite (SSC) cathode to lanthanum strontium magnesium gallium oxide (LSGM) electrolyte was investigated by electrochemical impedance spectroscopy (EIS) combined with X-ray diffraction (XRD). The XRD results showed that LaSrGa3O7 and LaSrGaO4 appeared at the interface between LSGM and SSC after sintering at high temperature. When the sintering temperature reached 1373 K, the high electronic conduction of the La-Sr-Co-O compound was formed. The decrease of open-circuit voltage and oxygen ion transfer number, and the increase of electronic conduction of LSGM electrolyte are the results of the cobalt diffusion from electrode to the LSGM film. The EIS results indicate that the electronic conduction of LSGM increases and the oxygen ion transfer number and open-circuit voltage decrease with increasing cathode sintering temperature, which are caused by the formation of LaSrGa3O7 and LaSrGaO4 at the interface of LSGM and SSC.更多还原