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

固体氧化物燃料电池（SOFC）是最高效的电力转换设备之一，它具有燃料灵活性，可以容纳来自污水厂、农场、垃圾填埋场的天然气和甲烷基生物气体，以及清洁要求相对较低的生物质气化产品。然而，由于电池的电子和离子电阻，在SOFC中会产生大量的损耗。这些损耗被称为欧姆极化，根据电池设计和操作条件的不同，通常可以占到SOFC电化学电位的40%以上。本研究将开发孔隙尺度模型，通过优化SOFC电极微观结构来提高性能，从而了解和减少欧姆损耗，从而使SOFC成为一种技术上和经济上可行的高效能源转换和可持续性替代品。x射线成像和模型开发的结合将用于实现这一目标。我们将1)使用PI和Xradia， Inc.开发的x射线计算机断层扫描（XCT）获得Adaptive Materials， Inc. （AMI）提供的多孔SOFC电极的亚50纳米分辨率三维重建作为分析输入，2)开发50纳米分辨率的孔隙级模型来描述电极微观结构中的电子和离子电荷转移。3)利用电荷转移预测和热应力分析确定XCT成像的SOFC电极结构的欧姆损失和结构完整性；4)利用Xradia对SOFC电极术前和术后的XCT成像和AMI进行的SOFC实验验证预测。开发的模型将用于以最小的欧姆损耗确定电极微结构。这项工作将与我们目前在陆军资助的碳氢燃料SOFC项目很好地结合起来，该项目侧重于电极孔隙结构气相区域的质量传输、内部改造和电化学。该活动将设在康涅狄格州全球燃料电池中心（CGFCC），该中心提供了美国最大的燃料电池科学和技术核心学术能力之一。该项目将包括2名研究生，1名本科生，并将开展涉及七年级到高中学生、教师和行业的外展活动。

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.