Abstract

In order to evaluate applicability of Ce_{0.6 –х}La_0.4Pr_хO_{2 – δ} (x = 0–0.2) fluorites for protective interlayers and electrode components for intermediate-temperature solid oxide fuel cells (SOFCs), their thermal expansion, chemical interaction with solid electrolyte material, tolerance towards reduction and electrochemical behavior were studied. The incorporation of praseodymium into Ce_0.6La_0.4O_{2 – δ} was found to increase unit cell parameters and thermal expansion coefficients, from (13.2 ± 0.3) × 10^–6 to (18.5 ± 0.8) × 10^–6 К^–1 at intermediate temperatures. Increasing total concentration of rare-earth cations in the fluorite-like cerium dioxide structure also correlates with decreasing thermodynamic stability under both oxidizing and reducing conditions. As a result, high-temperature chemical interaction between the Pr-doped materials and lanthanum gallate-based solid electrolyte becomes more intensive with respect to Ce_0.6La_0.4O_{2 – δ}, whilst reduction of Pr-containing solid solution may leads to segregation of a secondary phase with the C-type structure. The combination of these factors deteriorates compatibility of the interlayers with other SOFC components. Consequently, the overpotentials of PrBaFe_1.2Ni_0.8O_{6 – δ} cathodes in the electrochemical cells with (La_0.9Sr_0.1)_0.98Ga_0.8Mg_0.2O_{3 – δ} solid electrolyte were –42 and –143 mV in O₂ atmosphere at the current density –58 mA/cm² and 1073 K when the interlayers of Ce_0.6La_0.4O_{2 – δ} or Ce_0.5La_0.4Pr_0.1O_{2 – δ} were used, respectively.

中文翻译：

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类似于萤石的Ce 0.6 – x La 0.4 Pr x O 2 –δ作为固体氧化物燃料电池的电极组分的稳定性和功能特性

摘要

为了评价铈适用性_{0.6 - х}的La _0.4镨_х ö _{2 - δ}（X = 0-0.2）萤石用于保护中间层和电极组件中温固体氧化物燃料电池（SOFC），其热膨胀，化学相互作用用固体电解质材料，研究了还原耐受性和电化学行为。镨的掺入的Ce _0.6的La _0.4 ø _{2 - δ}，发现增加的晶胞参数和热膨胀系数，从（13.2±0.3）×10 ^-6至（18.5±0.8）×10 ^-6 К ^-1在中间温度下。萤石状二氧化铈结构中稀土阳离子总浓度的增加还与在氧化和还原条件下的热力学稳定性下降有关。结果，相对于Ce _0.6 La _0.4 O _2-δ，Pr掺杂材料与没食子酸镧基固体电解质之间的高温化学相互作用更加强烈，而含Pr固溶体的还原则可能导致Ce的偏析。具有C型结构的第二相。这些因素的组合降低了中间层与其他SOFC组件的兼容性。因此，PrBaFe _1.2 Ni _0.8的过电势ø _{6 - δ}在电化学电池用阴极（LA _0.9锶_0.1）_0.98镓_0.8镁_0.2 ø _{3 - δ}固体电解质是-42和-143毫伏为O ₂气氛中，在电流密度-58毫安/厘米²和1073 k当Ce的夹层_0.6的La _0.4 ø _{2 - δ}或Ce _0.5的La _0.4镨_0.1 ø _{2 - δ}分别使用。