Electric vehicles (EVs) play important roles in de-carbonize our transportation. Currently, Li-ion batteries (LiBs) are the state-of-the-art energy storage technology that powers EVs. Meanwhile, there is growing interest to use lithium metal as the anode to boost the energy density. For both technologies, Li deposition is an important phenomenon. In LiBs, Li deposition competes with Li insertion at the anode. Part of plated Li can become inactive and results in battery capacity loss and resistance increase. Li plating can also result in dendrite growth and cause internal short-circuit. However, the reversible Li deposition/striping can enhance the anode capacity. Therefore, Li deposition affects LiB’s energy density, charging performance, cycling stability and safety. In Li metal anode, Li deposition is the designed reaction, but competing reaction (e.g. SEI formation) and dead lithium compromises its columbic efficiency therefore cycling stability. Managing the morphology of the Li deposits is critical for both technologies.<br/><br/>In this talk, I will first talk about our work on the mechanism of Li plating on graphite particles, which is relevant for fast-charging Li-ion batteries. The onset condition of Li plating on graphite will be discussed with both experimental and simulation results. Then I will discuss the Li deposition mechanism on Si and Cu film in carbonate electrolytes, which is relevant for Li metal batteries. Morphological study based on SEM imaging will be coupled with theoretical analysis to understand the growth mechanism of island and whisker morphology on Si and Cu. The implication for Li metal anode's reversiblitiy and its resistance to internal short will be discussed based on the findings.

Understanding Li deposition mechanism on graphite, silicon and copper for Li-ion and Li metal batteries

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.