Sadia Yatir, Kerherve Gwilherm, Skinner Stephen J
Faculty of Engineering Materials Engineering, Bar Ilan University, Ramat Gan 5290002, Israel.
Material Engineering, Ben Gurion University of the Negev, P.O. Box 653, Beer-Sheva 8410501, Israel.
ACS Omega. 2025 Apr 28;10(18):19214-19223. doi: 10.1021/acsomega.5c02253. eCollection 2025 May 13.
Materials based on Sr-Ti-O have shown remarkable properties and have been used in a wide diversity of applications. However, very little investigation has gone into the Sr-Ti-O-F system, mainly due to the very high stability of its constituents such as SrF and TiO. In this work, solid-state reactions under reducing atmospheres on SrF and TiO showed highly interesting properties for the system, including high mixed electronic and ionic conductivity. XPS data further illuminate the results with the Ti 2p peaks shifting to higher binding energy due to fluorine interaction, possibly hinting at the formation of a TiO F phase. Testing using both ion blocking and electron blocking layers allowed the distinction between the ionic and electronic conductivity of the materials, showing very high ionic conductivity compared to most SrF-based compounds. Ionic conductivities of up to 1 mS cm for 2SrF:TiO samples near room temperature were obtained. The ionic transport numbers were found to be 20-60% over the 50-300 °C temperature range. The apparent activation energy for ionic conduction was surprisingly low with (ionic) = 0.05-0.10 eV for the different samples, whereas for electronic conductivity, (electron) = 0.11-0.32 eV.
基于Sr-Ti-O的材料已展现出卓越性能，并被广泛应用于各种领域。然而，对于Sr-Ti-O-F体系的研究却非常少，主要原因是其成分（如SrF和TiO）具有很高的稳定性。在这项工作中，在还原气氛下对SrF和TiO进行的固态反应显示出该体系具有非常有趣的性质，包括高混合电子和离子导电性。XPS数据进一步阐明了结果，由于氟的相互作用，Ti 2p峰向更高结合能移动，这可能暗示形成了TiO F相。使用离子阻挡层和电子阻挡层进行测试，能够区分材料的离子导电性和电子导电性，结果表明与大多数基于SrF的化合物相比，该材料具有非常高的离子导电性。在室温附近，2SrF:TiO样品的离子电导率高达1 mS cm。在50-300°C温度范围内，离子迁移数为20-60%。不同样品的离子传导表观活化能出奇地低， (离子)=0.05-0.10 eV，而电子导电性的 (电子)=0.11-0.32 eV。
