The poor performance and safety concerns of lithium (Li) metal anodes represent a critical challenge to enable high energy density rechargeable batteries. This is attributed to several well-known issues associated with Li metal electrodeposition and dissolution, including electrolyte decomposition, dendrite evolution, and “dead” Li accumulation. In addition, short-circuiting can occur due to the electrically conductive nature of metallic Li, in particular if a dendrite penetrates to the cathode during operation, which leads to significant safety concerns. However, there is a lack of fundamental knowledge on the origins of dendrite nucleation, the morphological evolution during growth and dissolution, and the exact mechanisms that lead to cell failure. As a result, the majority of research to date has focused on approaches that mitigate the symptoms of poor performance, rather than understanding or addressing the root causes.
Ultimately, all of the challenges associated with Li metal come down to the electrode-electrolyte interface, suggesting that new methods of interfacial engineering are required to rationally design solutions that simultaneously address the chemical, electrochemical, mechanical, and morphological challenges facing Li metal anodes.
In this talk, I will demonstrate several examples of interfacial engineering of Li metal anodes, including protective coatings by Atomic Layer Deposition (ALD), 3-D electrode architectures, and formation of low-impedance interfaces against solid electrolytes. Moreover, I will discuss the critical roll of in situ/operando analysis of Li metal during cycling to identify the mechanistic origins of the improved performance.
An improved fundamental understanding of the complex behavior of these electrodes is gained through correlation with continuum-scale modeling, which provides insight into the dominant surface kinetics.
I will also present new experimental results on the mechanical properties of Li metal, and their implications on coupled mechanical-electrochemical behavior. These results provide detailed insight into the interplay between morphology and the dominant electrochemical processes occurring on the Li electrode surface through an improved understanding of electrochemical “signatures”, which represent a powerful new platform for analysis. This broadly defines the critical field of interdisciplinary research that encompasses “interfacial engineering” of Li metal, and highlights the complementary roll that fundamental and applied research can play to solve one of the most critical challenges facing next-generation rechargeable batteries.
Speaker: Neil Dasbupta, Univ. of Michigan
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