(733a) Interfaces and Interphases in Next-Generation Battery Technologies

While lithium based battery technologies are becoming increasingly widespread in our energy landscape, both in electric vehicles and grid scale storage, room for improvement remains in continuing to increase energy density, reducing their costs, and improving the sustainability of their manufacturing. In this presentation, we will discuss recent progress in our group toward achieving these goals. Specifically, efforts to comprehensively characterize the reaction intermediates and organic SEI products of electrolyte reduction reactions in operando and ex situ will be detailed. Both EPR and ATR-FTIR spectroscopy are used to identify electrolyte reaction intermediates and products to clarify electrolyte reduction mechanisms for Li metal batteries. A particular focus is placed on fluorinated electrolytes, which have shown high performance in Li metal batteries but pose environmental concerns related to the longevity of PFAS compounds. Improved understanding of electrolyte reduction mechanisms will help to chart a path toward fluorine free electrolytes. We will also discuss the study of electrode-binder interfaces in critical-mineral free conversion cathodes and share findings of targeted binder-active material interactions that improve both reversibility and cycling stability of these promising electrode materials. With the understanding developed from studying these critical interfaces and interphases in promising electrode materials, we provide new insights into the formation and chemical nature of interphase components that promote stable cycling of high energy density lithium metal and conversion electrodes. Together, these chemistries offer a pathway toward high energy density and low cost storage while avoiding the use of critical minerals such as Ni and Co.