Lithium metal stripping beneath the solid electrolyte interphase

Abstract

Lithium stripping is a crucial process coupled with lithium deposition during the cycling of Li metal batteries. Lithium deposition has been widely studied, whereas stripping as a subsurface process has rarely been investigated. Here we reveal the fundamental mechanism of stripping on lithium by visualizing the interface between stripped lithium and the solid electrolyte interphase (SEI). We observed nanovoids formed between lithium and the SEI layer after stripping, which are attributed to the accumulation of lithium metal vacancies. High-rate dissolution of lithium causes vigorous growth and subsequent aggregation of voids, followed by the collapse of the SEI layer, i.e., pitting. We systematically measured the lithium polarization behavior during stripping and find that the lithium cation diffusion through the SEI layer is the rate-determining step. Nonuniform sites on typical lithium surfaces, such as grain boundaries and slip lines, greatly accelerated the local dissolution of lithium. The deeper understanding of this buried interface stripping process provides beneficial clues for future lithium anode and electrolyte design.

Direct observation of lithium metal dendrites with ceramic solid electrolyte

“…The inhomogeneous dissolution on the entire surface of Li could be related to the crystallographic orientations of different Li grains. Some crystallographic orientations could be more susceptible to Li dissolution than others 25 . The end of the cycling curve (Figure S3 ) also shows significant voltage fluctuations, indicating the consumption of Li electrode and the consequent loss of contact.…”

Customizing a Li–metal battery that survives practical operating conditions for electric vehicle applications

“…3i-k). 31 During the repeated platingstripping process, such densely packed and smooth Li morphology found on the LiNO 3 -treated Li-metal surface significantly suppressed the unwanted interfacial reaction between the electrolyte and Li-metal surface and exhibited the least amount of Li loss as a dead layer compared to the bare Li-metal ( Fig. 4a-f).…”

Recent Progress in Understanding Solid Electrolyte Interphase on Lithium Metal Anodes

“…found that under high‐rate electrochemical Li dissolution, the vigorous growth of voids causes a local collapse of SEI layer. [ 105 ] The breakdown sites react much faster than other areas, leading to pit growth. The total area coverage of pits increases as the current density increases.…”