This research project focuses on several oxide materials that are important in energy related applications. The central phenomena of interest are linked to internal stresses that are created by changes in composition (for example, adding and removing lithium in a battery material). The specific findings from this project are contributing directly to the development of improved electrodes for high energy density lithium ion batteries for hybrid and electric vehicles, and improved materials for applications in fuel cells and catalysis. Knowledge transfer is occurring through both public dissemination and direct interactions with researchers and General Motors.
TECHNICAL DETAILS: In ionic materials there is a complex interplay between internal stresses, defects in the material, electrochemical phenomena and kinetic processes (e.g., diffusion and phase transformations). These stresses lead to degradation and performance limitations in new materials that are being explored for both solid oxide fuel cells and lithium ion batteries. Scientific understanding of these stress-related issues is currently very limited. In this project, research into these phenomena is based on systematic and strategically planned investigations that closely integrate theory and experiments. The efforts at Brown University employ precise in situ measurements of stresses along with other experimental methods to develop novel approaches for probing a variety of complex phenomena where stress interactions with fundamental mechanisms are poorly understood (e.g., defect association, grain boundary segregation, multicomponent diffusion, etc.). Interpretation of these data relies on atomic scale modeling at Michigan State University. Students and faculty from both Universities are working directly with Dr. Yan Wu and other researchers at General Motors, in ways that expand educational outcomes and enhance knowledge transfer to industry. The overall understanding of stress effects on kinetic processes and degradation mechanisms obtained from this project is also relevant to a broader range of ionic solids.
