In this work, two perovskites (SrCo_0.95Ir_0.05O_3-δ and SrCo_0.95Ta_0.05O_3-δ) have been prepared, characterized, and tested as cathode materials for intermediate-temperature solid-oxide fuel cells, producing maximum power densities of 600 and 300 mW cm^–2 at 850 °C, respectively. The introduction of only a 5% of highly charged cations like Ir⁴⁺ and Ta⁵⁺ at the Co sites of the SrCoO_3−δ system stabilizes a tetragonal polytype, at room temperature, and improves some essential properties such as the electrical conductivity or the polarization resistances with the electrolyte. These two materials have been characterized by X-ray diffraction and neutron powder diffraction (NPD) at 25 °C; an in situ NPD analysis was carried out from 200 to 800 °C for SrCo_0.95Ta_0.05O_3-δ in order to study the thermal evolution of the crystal structure. In complement, the chemical or mechanical compatibility of these materials with La_0.8Sr_0.2Ga_0.83Mg_0.17O_3-δ electrolyte, and a thermogravimetric analysis from 25 to 900 °C are investigated. Finally, a XPS study confirms the surface oxidation states of Co, Ta, and Ir in the SrCo_0.95Ir_0.05O_3-δ and SrCo_0.95Ta_0.05O_3-δ perovskite specimens.

中文翻译：

---

M = Ir ⁴⁺，Ta ⁵⁺掺杂SrCo _0.95 M _0.05 O3 _-δ钙钛矿：有前途的固体氧化物燃料电池阴极

在这项工作中，制备了两种钙钛矿（SrCo _0.95 Ir _0.05 O3 _-δ和SrCo _0.95 Ta _0.05 O3 _-δ），进行了表征和测试，作为中温固体氧化物燃料电池的阴极材料，可产生最大功率密度在850°C时分别为600和300 mW cm ^–2。在SrCoO3 _-δ的Co位上仅引入5％的高电荷阳离子，如Ir ⁴⁺和Ta ⁵⁺该体系可在室温下稳定四方多晶型，并改善某些基本性能，例如电解质的电导率或极化电阻。这两种材料的特征是在25°C下进行X射线衍射和中子粉末衍射（NPD）。为了研究晶体结构的热演化，在200至800°C下对SrCo _0.95 Ta _0.05 O3 _-δ进行了原位NPD分析。作为补充，这些材料与La _0.8 Sr _0.2 Ga _0.83 Mg _0.17 O3 _-δ的化学或机械相容性电解质，以及在25至900°C下的热重分析。最后，XPS研究证实了SrCo _0.95 Ir _0.05 O3 _-δ和SrCo _0.95 Ta _0.05 O3 _-δ钙钛矿样品中Co，Ta和Ir的表面氧化态。