The morphology of the Li deposit governs the performance of lithium metal anode to a large extent. Previous studies have reported many different Li deposit morphologies: hemi-sphere, granular, columnar, whisker (needle-like), Eden cluster, mossy (bush-like), and dendrite (tree-like). To address the challenge of fast-charging LIBs and LMBs, managing Li deposit morphology during battery charging is critical.Nonetheless, the formation mechanism of different Li deposit morphologies remains less studied. To control the morphology, achieve highly reversible and compact Li deposition and prevent internal short-circuit, significant progresses have been made in engineering electrolyte compositions,SEI chemistry and substrate structures. These efforts have lead to high CE Li deposition/striping (up to 99.5%) at current densities below 1 mA cm-2. To further enhance the performance of Li metal anode, fundamental understanding of the nucleation and growth of Li is necessary. In particular, these questions need to be answered:1) How do deposits develop into different morphologies and how does the morphology correlate with CE and the tendency of internal-short? 2) What governs current heterogeneity and how does it correlates with CE and the risk of internal short-circuit? Understanding these questions will provide valuable insights to guide the rational design of electrolyte and substrates for high-capacity and reversible Li metal anode (&gt; 5 mAh cm-2, &gt; 1000 cycles), high-energy LIB capable of ultra-fast charging ( &gt;5 C ), and enhanced safety for both technologies. In this work, we reveal the mechanism of Li deposition on Si and Cu substrates by combing electron imaging, electrochemical tests with theoretical analysis. Specifically, we are interested in these questions: 1) Under what conditions will Li plating happen? 2) Once initiated, how does Li nucleate and grow? 3) How do various factors (particularly current, substrate and temperature) regulate the morphology of the deposited Li? 4) How does the morphology affect the deposition/stripping reversibility?

Li deposition mechanism: A perspective gained by combining imaging with Theoretical analysis

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ACS Fall 2022

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