NSF-DFG MISSION: "INCUBATOR - Exploring the Interfacial Chemistry in Sulfide-Based Solid-State Batteries by Soft and Hard X-ray Spectroscopies Under Operating Conditions"

Solid-state batteries (SSBs) have emerged as strong contenders for next generation LIB technologies as they are expected to achieve higher energy and power densities and increased safety through replacement of liquid electrolyte formulations with solid electrolytes. This recent global and commercial interest in SSBs has helped illuminate the key challenges for the realization of this technology, such as increased understanding and control of the solid-state composite cathodes and the impact of the active material/solid electrolyte interfaces. Supported by the Division of Chemistry at NSF and DFG, Profession Guo from University of California-Santa Cruz in US, and Dr. Adelhelm at Humboldt University and Dr. Bär at HZB in Germany will work together focus on studying new cathode chemistries for SSBs, including materials development and multi-modal characterization of their properties and interfaces with solid electrolytes. The collaboration also provides students the opportunities to be exposed to international research activities and different culture. An understanding of the processes at the interfaces and in bulk that occur in batteries requires obtaining qualitative and quantitative atom-specific information under realistic operating conditions at relevant time scales. X-ray spectroscopies are critical tools to achieve this understanding. State-of-the art high-brilliance synchrotron sources provide a powerful means to use photons for probing buried interfaces. The ability to study buried interfaces is of great importance for energy storage devices, such as batteries. The international team supported by this grant will develop a mechanistic understanding of the redox and decomposition processes occurring in sulfide-based electrode/electrolyte composites. Achieving this goal is dependent on the development of a new multi-modal characterization platform that enables experiments with high energy resolution on different length scales. This new platform will enable the study of SSBs under in-situ and operando conditions by XAS and RIXS for an atom-specific understanding of electrochemical phenomena and associated degradation processes at electrode/electrolyte. 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.