(Invited, Digital Presentation) Chemo-Mechanics in Lithium Metal Solid State Batteries

Abstract

Transportation accounts for 23% of energy-related carbon dioxide emissions and electrification is a pathway toward ameliorating these growing challenges. All solid state batteries could potentially address the safety and driving range requirements necessary for widespread adoption of electric vehicles. However, the power densities of all-solid state batteries are limited because of ineffective ion transport at solid|solid interfaces. New insight into the governing physics that occur at intrinsic and extrinsic interfaces are critical for developing engineering strategies for the next generation of energy dense batteries. However, buried solid|solid interfaces are notoriously difficult to observe with traditional bench-top and lab-scale experiments. Understanding material transformations within these interfaces is critical for assessing failure onset and growth mechanisms in solid electrolytes is necessary for high performance solid-state batteries. While phenomenological understanding of failure mechanisms in garnet solid electrolytes exist, limited experimental validation is available. Herein, we examine the two predominant failure mechanisms observed in lithium metal solid state batteries: (1) filament formation, and (2) isolated lithium plating. We combine a suite of ex situ diagnostic techniques with in situ x-ray imaging to probe material transformation and chemo-mechanics and lithium metal-solid-electrolyte interfaces. Operating conditions as well as material processing conditions are discussed.