Abstract Mixed ionic-electronic conductors derived from Ruddlesden-Popper type Sr3LaFe3O10−δ are promising materials for numerous energy- and environment-related applications, such as electrodes of fuel cells, batteries and capacitors. In this work, oxygen deficiency and electrical conductivity of Sr3LaFe3−xAlxO10−δ (x = 0.3–0.6) were studied at 973–1273 K in the oxygen partial pressure range from 10−24 to 0.8 atm. The p(O2)-T-δ diagrams determined by coulometric titration and thermogravimetry, were described by a statistical thermodynamic model taking into account the site-exclusion effects near oxygen vacancies, energetic non-equivalence of different crystallographic sites, and partial localization of electron holes in the vicinity of Al3+ cations. Doping with Al3+ was found to increase oxygen nonstoichiometry under oxidizing conditions and to decrease the electronic charge-carrier concentrations. Although the oxygen vacancy mobility tends to decrease on doping due to stable tetrahedral coordination of Al3+ cations, a moderate increase in the ionic conductivity with respect to parent Sr3LaFe3O10−δ is observed at x = 0.3 and temperatures below 1100 K.

中文翻译：

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Al掺杂Sr3LaFe3O10-δ的氧化还原行为和离子电导率

摘要 源自 Ruddlesden-Popper 型 Sr3LaFe3O10-δ 的混合离子电子导体是许多能源和环境相关应用的有前途的材料，例如燃料电池、电池和电容器的电极。在这项工作中，在 10-24 至 0.8 个大气压的氧分压范围内，在 973-1273 K 下研究了 Sr3LaFe3-xAlxO10-δ (x = 0.3-0.6) 的氧缺陷和电导率。由库仑滴定法和热重法测定的 p(O2)-T-δ 图由统计热力学模型描述，考虑到氧空位附近的位点排斥效应、不同晶体学位点的能量非等效性以及电子的部分定位Al3+ 阳离子附近的空穴。发现掺杂 Al3+ 会增加氧化条件下的氧非化学计量，并降低电子电荷载流子浓度。尽管由于 Al3+ 阳离子的稳定四面体配位，氧空位迁移率趋于降低，但在 x = 0.3 和温度低于 1100 K 时观察到相对于母体 Sr3LaFe3O10-δ 的离子电导率适度增加。