Solid oxide cells are a rapidly developing technology for clean efficient conversion of fuels-to-electricity and electricity-to-fuels. While much of the development has been as solid oxide fuel cells for stationary power generation, important new applications have emerged that are critical for reducing greenhouse gas emissions, including electricity storage, conversion of renewable electricity to fuels, and fuel-flexible range extenders for electric vehicles. A key barrier to more widespread application of solid oxide cells is their limited operating lifetime - more research is needed to understand and ultimately mitigate degradation mechanisms that limit lifetime. This project provides a fundamental understanding of degradation processes that complements more practical studies, e.g., long-term fuel cell life tests, being carried out in industry. The project is achieving this understanding by developing and testing theoretical models based on measurements of device performance degradation and three-dimensional imaging of device damage. The project involves an industrial partner, Nissan, Inc., ensuring that cells are tested under application-relevant conditions. The results are relevant to many research communities, ranging from modelers who can utilize three-dimensional data and simulation methods, to industrial developers who can use the results to help improve their fuel cells. Graduate, undergraduate, and high-school students receive extensive training that will be valuable in their future careers - they find employment in energy-related industries, auto manufacturers, and many others. Student diversity is emphasized. Dissemination of the challenges and results with the public occur through two forums: Science Cafe in Evanston and the Ann Arbor Hands-On Museum, the latter attracts youngsters from surrounding communities that are disadvantaged (e.g., Ypsilanti) and/or rural (majority of communities in Washtenaw and its surrounding counties).
TECHNICAL DETAILS: This project focuses on solid oxide cell performance and long-term stability; this is currently relevant because new applications involving cyclic operation introduce new degradation mechanisms. Three-dimensional imaging of fuel cell structure is carried out using focused ion beam - scanning electron microscopy, atom-probe tomography, and transmission X-ray microscopy, the latter done in a way that directly observes structural and chemical changes due to cell operation. These images are combined with three-dimensional simulations of electrode performance and structural evolution based on the phase field modeling, which will utilize high performance computing. This addresses a key challenge - to develop simulation models based on microstructural changes observed in short accelerated tests, and then apply them to accurately predict long-term (beyond 5 years) performance changes. This combination of 3D microstructures, validated simulation tools, and computationally intensive data analysis provides a framework that is broadly useful for design and discovery of electrode materials. Students receive training in state-of-the-art experimental and theoretical research methods, and directly interact with industrial and national laboratory researchers, the latter to utilize powerful three-dimensional imaging capabilities at Argonne and Brookhaven National Laboratories.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
