Simultaneously characterizing interphase architecture and interfacial Li transport in Li metal batteries
Presented by Prof. Lauren Marbella
Although Li metal anodes offer the highest possible specific energy density for Li-based batteries, practical application is plagued by the growth of high surface area Li filaments. The presence of Li filaments is strongly correlated with the formation of dead (electrochemically inactive) Li that leads to low Coulombic efficiency (CE) and serious safety concerns due to short-circuiting. The morphology of Li deposits that form during Li stripping and plating is highly dependent on the composition and the structure of the solid electrolyte interphase (SEI) that forms upon exposure of Li metal to the electrolyte and continues to evolve during electrochemical cycling. In the first half of my talk, I will discuss our work on using a combination of nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopies (XPS) to show that fast Li transport and low solubility at the electrode/SEI interface are responsible for the formation of low surface area, bud-like deposits that form upon addition of LiNO3 to ether-based electrolytes for Li metal batteries. This improved performance in the presence of LiNO3 is observed despite the fact that there are higher quantities and more types of compounds in the SEI compared to a control electrolyte, suggesting that the arrangement of the electrolyte decomposition products into a multilayer pattern alters Li plating behavior. SEI design strategies that increase SEI stability and allow for more uniform Li flux to the electrode are thus expected to produce a more even current distribution. In the second half of my talk, I will examine failure modes of Li metal batteries when paired with solid electrolytes. Here, we combine MRI with operando acoustics measurements to simultaneously assess chemical and mechanical changes at the interface between Li metal and Li7La3Zr2O12 (LLZO) as a function of stack pressure during galvanostatic polarization. Insight from this work suggests that low stack pressure may lead to undesirable compounds at the Li/LLZO interface, in addition to interfacial voids due to poor contact at the solid/solid interface.
Lauren Marbella is an Assistant Professor in the Department of Chemical Engineering at Columbia University. Her research group focuses on understanding the relationship between electrochemical performance and interfacial chemistry in devices for energy storage and conversion. Her research relies heavily on the use of nuclear magnetic resonance imaging (MRI) and spectroscopy to evaluate changes in material properties in real time to elucidate the chemical mechanisms underpinning degradation in Li and beyond Li ion battery systems. Marbella’s research has received numerous awards including the Cottrell Scholar Award (2022), the National Science Foundation (NSF) Faculty Early Career Development (CAREER) Award (2021), and the Scialog Collaborative Innovation Award for Advanced Energy Storage (Sloan Foundation, 2019).
Marbella received her PhD in chemistry from the University of Pittsburgh in 2016, under the direction of Prof. Jill Millstone. In 2017, she was named a Marie Curie Postdoctoral Fellow at the University of Cambridge in the group of Prof. Clare Grey. There, she was also named the Charles and Katharine Darwin Research Fellow, which recognizes the top junior fellow at Darwin College at the University of Cambridge. She joined the chemical engineering faculty at Columbia University in 2018.