Lithium Metal Morphology & Performance Informed by Micro-Computed Tomography

Alone, <i>ex-situ</i> analysis and <i>postmortem </i>teardowns often convolute interpretations of lithium metal cell failure modes. In this study, micro-computed tomography renders lithium metal interfaces in various conditions and formats throughout cycling to assist in better understanding the morphology of cycled lithium and its relationship with cycling performance. <i>Operando </i>studies link cycling performance with morphology with greater resolution and provide insight into physical phenomena such as deformation of the separator imposed by the lithium metal volume changes. Rolled lithium foils, stack pressure, inorganic-organic hybrid coatings, electrolyte solvent types, and polymer separator morphology is investigated. With this methodology, hairy nanoparticle-based artificial SEIs are found to promote uniform and dense lithium cycling, and their chemo-mechanical interplay which supports this mechanism is studied. Finally, the findings inform best practices in fundamental lithium metal cell design.