This project focuses on surface damage layers that form on many of the oxide materials that are used in lithium-based batteries. Most of the research is designed to understand the formation of these layers, and to create strategies that can mitigate related degradation mechanisms in battery materials. The specific findings from this project will help to increase the lifetime of lithium-based batteries that are used in a variety of applications. Through the GOALI partner (General Motors), the work will contribute directly to industrial research on improved electrodes for high energy density lithium ion batteries for electric vehicles with zero emission. Knowledge transfer is occurring through both public dissemination and direct interactions with researchers at General Motors.
TECHNICAL DETAILS: Many of the battery materials that can potentially improve the performance of lithium-based batteries are ceramics where surface damage layers (SDLs) cause serious limitations. For example, chemically and electrochemically induced structural changes that form surface films on layered cathode particles lead to substantial impedance rise and limited cycle life - to the extent that SDLs render these materials unusable after cycling. In all of these surface films, it is important to realize that a variety of factors lead to significant mechanical stresses, where the corresponding elastic energies interact with chemical and structural changes in ways that have not been addressed in most prior research. The need to develop fundamental knowledge about chemo-mechanical effects in SDLs and surface coatings is the primary motivation for the proposed research. 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 coupling, multicomponent diffusion, etc.). Interpretation of these data relies on building multiscale models informed by atomic scale simulations 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. Via these direct interactions with industrial collaborators, the resulting new knowledge will be applied to commercially viable systems.
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.