GOALI: Pore-Scale Understanding of Ohmic Polarization in Solid Oxide Fuel Cell Electrodes

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CBET-0828612ChiuThe solid oxide fuel cell (SOFC) is one of the most efficient electrical conversion devices with the fuel flexibility to accommodate both natural gas and methane-based biogases from wastewater plants, farms, landfills, and products from biomass gasification with relatively low cleaning requirements. However, substantial losses can arise in a SOFC due to the cell's electronic and ionic resistances. These losses, which are known as ohmic polarization, can generally account for upwards of 40% of the SOFC's electrochemical potential depending on the cell design and operating conditions. This research will develop pore-scale models to understand and reduce ohmic losses by optimizing the SOFC electrode microstructure for enhanced performance, thus enable the SOFC to be adopted as a technologically and economically viable alternative for efficient energy conversion and sustainability.A combination of x-ray imaging and model development will be used to achieve this goal. We will 1) use x-ray computed tomography (XCT) developed by the PI and Xradia, Inc. to obtain sub-50 nm resolution 3-D reconstruction of porous SOFC electrodes provided by Adaptive Materials, Inc. (AMI) as input for analysis, 2) develop pore-level models at 50 nm resolution to describe electronic and ionic charge transfer in the electrode microstructure, 3) determine ohmic losses and structural integrity of XCT-imaged SOFC electrode structures using charge transfer predictions coupled with thermal stress analysis, and 4) validate predictions with XCT imaging of pre- and post-operational SOFC electrodes at Xradia and SOFC experiments performed at AMI. Models developed will be used to determine electrode microstructures with minimal ohmic losses. This work will integrate well with our current Army-funded effort on hydrocarbon-fueled SOFC that focuses on mass transport, internal reformation and electrochemistry in the gas phase region of the electrode's pore structure. This activity will be located at the Connecticut Global Fuel Cell Center (CGFCC), which offers one of the largest core academic capabilities in fuel cell science and technology in the nation. The program will involve 2 graduate students, 1 undergraduate student, and will have outreach activities involving 7th grade to high school students, teachers and industry.