Perovskites within the (La,Sr)(Fe,Co)O3 class of materials show variations in the oxygen stoichiometry depending on temperature and oxygen activity and can potentially be used as catalysts, electrodes in high-temperature solid oxide fuel cells, gas sensors or for oxygen transport membranes. These perovskites possess a mixed ionic and electronic conductivity (MIEC), which can be highly beneficial for the processes on oxygen electrode surfaces. The oxygen transport through a MIEC is determined by the rate of the oxygen exchange over the gas-solid interface and the diffusivity of oxide ions and electrons (or holes) in the bulk. The oxygen exchange process over the surface in general involves several reaction steps, O2 adsorption, dissociation, charge transfer and incorporation of ionic species. The Co-free end member of the material class; LSF (e.g. (La0.6Sr0.4FeO3-δ) is fairly low cost and chemically stable in both mildly reducing and oxidizing atmosphere. The electronic conductivity is excellent (283 S/cm at 800 °C) but the ionic conductivity especially at low temperature is limited (0.014 S/cm, 800 °C). Due to these properties the material is a candidate for use in composite membranes in combination with a better ionic conducting material like CGO. Such systems are also excellent model systems for fundamental studies of the oxygen exchange process
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机译：（La，Sr）（Fe，Co）O3类材料中的钙钛矿根据温度和氧气活度显示出氧气化学计量的变化，并且可能用作催化剂，高温固体氧化物燃料电池中的电极，气体传感器或用于氧气传输膜。这些钙钛矿具有混合的离子电导率和电子电导率（MIEC），对于氧电极表面的工艺非常有利。通过MIEC的氧气传输取决于气固界面上的氧气交换速率以及主体中氧化物离子和电子（或空穴）的扩散率。表面上的氧气交换过程通常涉及几个反应步骤，氧气的吸附，离解，电荷转移和离子种类的结合。材料类别的无钴最终成员； LSF（例如（La0.6Sr0.4FeO3-δ）成本较低，并且在轻度还原和氧化气氛中均化学稳定。电子电导率极佳（在800°C时为283 S / cm），但离子电导率尤其是在低温下极限温度（0.014 S / cm，800°C）。由于这些特性，该材料是与更好的离子导电材料（如CGO）结合使用的复合膜候选材料。氧气交换过程
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