Perovskite-Structured BaScO2(OH) as a Novel Proton Conductor: Heavily Hydrated Phase Obtained via Low-Temperature Synthesis

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• 作者：Rinlee B. Cervera ; Shogo Miyoshi ; Yukiko Oyama ; Youssef E. Elammari ; Takehiko Yagi ; Shu Yamaguchi
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：May 14, 2013
• 年：2013
• 卷：25
• 期：9
• 页码：1483-1489
• 全文大小：426K
• 年卷期：v.25,no.9(May 14, 2013)
• ISSN：1520-5002

文摘

A novel proton-conducting material, BaScO₂(OH) has been successfully fabricated. The known high-temperature proton conductors are typically perovskite-type oxides, in which the proton concentration is determined by hydration reaction of oxygen vacancies introduced by a small amount of acceptor dopant. On the other hand, the novel material BaScO₂(OH) is still associated with the A²⁺B⁴⁺O₃ perovskite structure but with the B-site cation fully consisting of an acceptor cation Sc³⁺, which facilitates to retain an appreciable amount of protonic defects. While it is difficult to obtain the material by simply hydrating the unhydrated form (Ba₂Sc₂O₅), a combination of a new low-temperature sol鈥揼el synthesis and ultrahigh-pressure (4 GPa) compaction at room-temperature enables us to obtain the heavily hydrated phase BaScO₂(OH) due to on-synthesis hydration. The BaScO₂(OH) synthesized has been proved to be a pseudocubic perovskite phase with XRD and Raman analyses. The thermal dehydration analyses have verified the composition BaScO₂(OH) in terms of proton concentration, and their mobile nature has been observed with in situ FT-IR analysis. The protonic conductivity of the material is as high as 1.7 脳 10^鈥? S路cm^鈥? at 500 掳C, which is well higher than the total conductivity of the best proton-conducting perovskite oxides at intermediate temperature range.

Keywords:

proton conductor; perovskite oxide; BaScO₂(OH); low-temperature synthesis; solid electrolyte