Novel Chemically Stable Ba3Ca1.18Nb1.82鈥?i>xYxO9鈭捨?/sub> Proton Conductor: Improved Proton Conductivity through Tailored Cation Ordering

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• 作者：Siwei Wang ; Yan Chen ; Shumin Fang ; Lingling Zhang ; Ming Tang ; Ke An ; Kyle S. Brinkman ; Fanglin Chen
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：March 25, 2014
• 年：2014
• 卷：26
• 期：6
• 页码：2021-2029
• 全文大小：539K
• 年卷期：v.26,no.6(March 25, 2014)
• ISSN：1520-5002

文摘

Simple perovskite-structured proton conductors encounter significant challenges to simultaneously achieving excellent chemical stability and proton conductivity that are desirable for many important applications in energy conversion and storage. This work demonstrates that Y-doped complex-perovskite-structured Ba₃Ca_1.18Nb_1.82鈥?i>xY_xO_{9鈭捨?/sub> materials possess both improved proton conductivity and exceptional chemical stability. Neutron powder diffraction refinement revealed a Fm3̅m perovskite-structure and increased oxygen vacancy concentration due to the Y doping. High-resolution TEM analysis confirmed the perturbation of the B site cation ordering in the structure for the Ba3Ca1.18Nb1.82鈥?i>xYxO9鈭捨?/sub> materials. Such combined effects led to improved proton conductivity with a value of 5.3 脳 10^鈥? S cm^鈥? at 600 掳C for Ba3Ca1.18Nb1.52Y0.3O9鈭捨?/sub> (BCNY0.3), a value 2.4 times higher compared with that of the undoped Ba3Ca1.18Nb1.82O9鈭捨?/sub>. The Ba3Ca1.18Nb1.82鈥?i>xYxO9鈭捨?/sub> materials showed remarkable chemical stability toward water and demonstrated no observable reactions to CO2 exposure. Ionic transport number studies showed that BCNY0.3 had predominantly proton conduction below 600 掳C. Solid oxide fuel cells using BCNY0.3 as an electrolyte demonstrated cell power output of 103 mW cm^鈥? at 750 掳C. These results suggest that a doping strategy that tailors the cation ordering in complex perovskites provides a new direction in the search for novel proton conducting ceramics.}