Impact of SEI Formation History on Lithium Metal Electrode Stability at Elevated Temperatures
Year: 2026
Type: preprint
Abstract: Solid electrolyte interphase (SEI) is critical for stabilizing lithium metal anodes, yet its evolution under thermal stress and the role of its formation history remain poorly understood. Here, lithium plating and stripping on Cu electrodes were investigated in 1.0 and 5.0 M lithium bis(fluorosulfonyl)imide (LiFSI)/propylene carbonate electrolytes at 25 and 80 °C using electrochemical measurements, Raman spectroscopy, hard X-ray photoelectron spectroscopy (HAXPES), and X-ray absorption spectroscopy (XAS). Raman spectra showed that the bulk solvation structure changed little with temperature, whereas HAXPES and XAS revealed that elevated temperature accelerated LiFSI decomposition, inorganic enrichment, and SEI growth, leading to increased interfacial resistance and unstable cycling. Electronic-structure calculations showed that increasing LiFSI concentration enhanced the FSI− contribution to the lowest unoccupied molecular orbital (LUMO), while elevated temperature lowered FSI−-derived unoccupied states, favoring anion reduction. Pre-cycling at room temperature markedly improved subsequent operation at 80 °C, particularly with the concentrated electrolyte. These results demonstrate that high-temperature stability is governed by the combined effects of electrolyte concentration, temperature, and SEI formation history, providing a mechanistic basis for controlling SEI formation and stabilizing lithium plating and stripping under thermal stress.
Source: ChemRxiv
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212071968