Structure, Reactivity and Transport at Surfaces and Interfaces of Doped Ceria Electrolytes and Cermets: An In Situ Atomic Resolution Investigation

非技术性描述：随着社会向可持续能源发展，开发有效的发电方法是一个关键目标。固体氧化物燃料电池是一种有效地将化学燃料中储存的能量直接转化为电能的有前途的方法。这些陶瓷电池在高温下运行，可以利用各种燃料，如天然气，生物燃料和汽油。与其他燃料电池技术相比，这种燃料灵活性是固体氧化物燃料电池的显著优势。不幸的是，这些设备是昂贵的，并且由于它们的高操作温度而没有显示出长期稳定性。这些问题中的许多问题可以通过开发新材料来解决，这些新材料将允许固体氧化物燃料电池在较低温度下可靠地运行。新材料的开发需要关于材料在燃料电池中存在的苛刻条件下的行为的信息。该项目利用了一种强大的技术，电子显微镜，它可以直接观察原子水平的变化发生在材料的条件下类似于那些存在于真实的燃料电池。这些信息提供了对结构重排如何导致正或负材料功能的基本理解。 反过来，这些信息被用来帮助设计新材料，以提高燃料电池的性能。研究生、本科生和高中生都参与了这项研究。这些研究活动帮助他们了解如何利用材料研究来解决重要的社会问题，如可持续能源技术的发展。技术问题：离子传输特性和化学反应性是影响固体氧化物燃料电池技术的关键因素。与高温操作相关的成本和长期稳定性问题是尚未解决的材料设计挑战。这些问题促使了所谓的中温固体氧化物燃料电池的发展，该燃料电池采用能够在较低温度（500 - 700 ℃）下提供高离子电导率和催化活性的新型材料。掺杂的氧化铈是非化学计量的稀土氧化物，其显示出高离子电导率和期望的催化性能，使它们成为用于中温应用的潜在候选者。然而，还有一些重要的科学问题尚未解决，这些问题与电解质中的晶界以及阳极中的陶瓷-金属和固体-气体界面的相互作用有关。本项目通过使用原位像差校正电子显微镜沿着与单色电子能量损失谱来解决这些问题，以发展对这些界面过程的基本原子水平的理解。纳米结构和化学影响离子导电性和电解质和阳极金属陶瓷的反应性正在确定。一种新的实验方法正在开发中，允许在电化学条件下的电瓷原位原子分辨率的观察。这项研究具有潜在的变革性，因为它提供了有关结构和化学与电化学和电瓷功能的动态过程的新信息。该研究项目旨在培养研究生和本科生了解能源相关氧化物材料的发展并为之做出贡献。

NON-TECHNICAL DESCRIPTION: Developing efficient methods for generating electricity is a critical goal as society moves towards sustainable energy. Solid oxide fuel cells are a promising approach for efficiently converting the energy stored in chemical fuels directly to electricity. These ceramic cells run at high temperatures and can utilize a wide range of fuels such as natural gas, biofuels and gasoline. This fuel flexibility is a significant advantage of solid oxide fuel cells compared to other fuel cell technologies. Unfortunately, these devices are expensive and do not show long term stability because of their high operating temperatures. Many of these issues may be solved by developing new materials that would allow reliable operation of the solid oxide fuel cell at lower temperatures. Development of novel materials requires information on the behavior of materials under the harsh conditions present in a fuel cell. This project utilizes a powerful technique, electron microscopy which enables direct observation of atomic level changes taking place in materials under conditions similar to those present in a real fuel cell. This information provides a fundamental understanding of how the structural re-arrangements result in positive or negative materials functionalities. In turn, this information is being used to help in the design of new materials for improved fuel cell performance. Graduate, undergraduate and high school students are involved in this research. These research activities help them to understand how materials research can be employed to address important societal problems like the development of sustainable energy technologies.TECHNICAL DETAILS: Ionic transport properties and chemical reactivity are key factors impacting solid oxide fuel cell technologies. Cost and long-term stability problems associated with high temperature operation are unresolved materials design challenges. These issues have motivated the development of so-called intermediate temperature solid oxide fuel cells which employ novel materials that can deliver high ionic conductivity and catalytic activity at lower temperatures (500 - 700 C). Doped cerias are nonstoichiometric rare earth oxides which show high ionic conductivity and desirable catalytic properties making them potential candidates for use in intermediate temperature applications. However, there are important unresolved scientific questions related to interactions across grain boundaries in electrolytes as well as ceramic-metal and solid-gas interfaces in anodes. This project addresses these questions by using in situ aberration corrected electron microscopy along with monochromated electron energy-loss spectroscopy to develop a fundamental atomic level understanding of these interfacial processes. The nanoscale structures and chemistries affecting ionic conductivity and the reactivity in electrolytes and anode cermets are being determined. A new experimental approach is being developed to allow in situ atomic resolution observations of electroceramics under electrochemical conditions. This research is potentially transformative because it is providing new information on the dynamic processes relating structure and chemistry with electrochemical and electroceramic functionalities. This research project is training graduate and undergraduate students to learn about and contribute to the developments in energy-related oxide materials.