GOALI: Chemomechanical Failure Mechanisms in Inorganic Solid Electrolytes

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NON-TECHNICAL DESCRIPTION: Solid electrolytes are the enabling material for the successful development of solid-state batteries. Ceramic and glass solid electrolytes with sufficiently high ionic conductivities have been developed in recent years, however, these materials still face significant challenges. The research in this project addresses degradation mechanisms that are associated with the combined effects of chemical and mechanical phenomena. The transformative impact of this work is being demonstrated through substantial improvements in the performance of solid-state batteries. Implementation is facilitated by direct collaborations with the GOALI partner, which includes work on the synthesis and testing of novel electrolytes. Researchers from Brown University are working directly with Dr. Xingcheng Xiao and others at General Motors (GM), in ways that expand educational outcomes and enhance knowledge transfer to industry. Via these direct interactions with industrial collaborators, the resulting new knowledge is being applied to commercially viable systems. TECHNICAL DETAILS: Solid-state lithium batteries provide key improvements compared to traditional lithium-ion batteries based on liquid electrolytes. In particular, the implementation of solid electrolytes can potentially increase energy density through the safe use of Li metal anodes. This research project employs precise in situ stress measurements along with other experimental methods to investigate a variety of chemo-mechanical phenomena in solid electrolytes (e.g., Li metal penetration, large scale bridging effects in nanocomposites, viscoplasticity in sulfide glasses, etc.). This includes focused efforts to understand and mitigate the formation of dendrite-like lithium filaments, a critical failure mechanism where mechanical stresses appear to play an important role. This and other aspects of chemo-mechanical degradation are being investigated with research on three distinct types of materials: (1) single phase ceramic oxides (primarily garnet-type materials) that undergo purely elastic deformation; (2) nanocomposite electrolytes where nanoplatelets, nanotubes, and nanofibers increase the fracture toughness; (3) sulfide glass electrolytes that are subject to rate dependent deformation. Interpretation of these data is based on detailed finite element modeling. Extensive collaborations with the GOALI partner facilitate knowledge transfer to industry. Education elements of this project include a doctoral student working as a summer intern at GM, and research training opportunities at Brown University for undergraduate women from Wellesley College.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.