| Today's energy concerns have never been more dire and the need for increases in energy efficiency, conservation, and renewable resources is important for global health. Solid Oxide Fuel Cells (SOFCs) are highly efficient, fuel flexible, and low-emission electricity generation systems that can operate directly on natural gas using current infrastructure and readily available fuels. These systems can achieve much higher efficiency than current natural gas power plants, but unfortunately, have seen only limited commercialization due to issues of cost, durability, and performance.;In this thesis, investigation of the relationship between SOFC electrode structure and performance is quantified, allowing detailed understanding of the underlying phenomena that limit performance and durability. This is accomplished through the recent development of sophisticated three-dimensional structural analysis techniques: Focused Ion Beam—Scanning Electron Microscopy (FIB-SEM) tomography and X-ray Computed Tomography (XCT). Structural quantification is correlated with electrochemical performance analysis to gain insight into electrode behavior.;First, optimization and automation of reconstruction techniques are discussed, including a look at methods developed for rigorous error analysis. Next, the techniques are applied to SOFC electrodes and compared with structures simulated via stochastic Monte Carlo methods. The comparisons demonstrate the importance of the three-dimensional reconstruction techniques to properly quantify SOFC electrode structure.;Experimental work includes a novel reconstruction of an entire working solid oxide fuel cell. Limitations in the full device are understood through one-dimensional electrochemical modeling and lead to suggested improvements for electrode design.;Cathode processing conditions are also varied, leading to large differences in structure and performance. These are again correlated through modeling and lead to quantitative understanding of performance limitations in ceramic powder processed cathode materials.;Finally, an accelerated degradation testing protocol is developed and implemented on SOFC anodes. Structural changes are observed in three-dimensions and demonstrate a unique behavior in the electrode porosity which is partly responsible for the performance degradation observed. |
