About this Abstract |
| Meeting |
MS&T25: Materials Science & Technology
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| Symposium
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ACerS Robert B. Sosman Award Symposium
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| Presentation Title |
A Deep Dive into the Structure, Transport, and Surface Exchange Kinetics of the BaCoxFe0.8-xZr0.1Y0.1O3-d (BCFZY, 0.1≤x≤0.7) Triple-Conducting Oxide System |
| Author(s) |
Ryan O'Hayre, Yewon Shin, Michael D. Sanders, Zhen Jiang, Christopher M. Wolverton, Sossina M. Haile, Kennedy Agyekum, Bernadette Cladek, Katharine Page, Jue Liu, Bright Ogbolu, Erica Truong, Yan-Yan Hu |
| On-Site Speaker (Planned) |
Ryan O'Hayre |
| Abstract Scope |
Triple-conducting oxides (TCOs) are mixed-conducting materials with exceptional oxygen reduction/evolution reaction activity in high-temperature ceramic electrochemical cells. Their activity stems, partly, from their ability to incorporate and transport three charge carriers: protons, oxygen vacancies, and electron-holes. Despite their promise, fundamental studies of TCOs are challenging, as dynamics from three carriers cannot be fully disentangled via traditional electrical techniques. Characterizing protons is particularly difficult as they are generally the minority carrier; their conduction response is consequently obscured. Here, for the first time, we successfully isolate the proton behavior in an archetypal TCO, BaCoxFe0.8-xZr0.1Y0.1O3-d (BCFZY), through a unique combination of non-electrical characterization techniques.
We find that oxygen vacancies greatly exceed protons, despite the application of BCFZY in proton conducting devices. However, the proton mobility far exceeds the oxygen vacancy mobility. Consequently, the proton kinetics exceed the oxygen vacancy kinetics at relevant application temperatures (≤ 500 °C), despite their exceptionally low concentration (~ 0.001 H per formula unit). Thus, further electrocatalytic enhancements in BCFZY and related TCO systems will (surprisingly) require accelerating the oxygen (rather than proton) kinetics. |