Quantifying Graphite Solid-Electrolyte Interphase Chemistry and its Impact on Fast Charging

Eric McShane, Helen Bergstrom, Peter Weddle, David Brown, Andrew Colclasure, Bryan McCloskey

Research output: Contribution to journalArticlepeer-review

26 Scopus Citations

Abstract

The solid-electrolyte interphase (SEI) enables the remarkable capacity retention of lithium-ion batteries, yet a comprehensive quantitative description of the SEI composition remains elusive. Using a combination of differential electrochemical mass spectrometry and mass spectrometry titration, we quantify graphite SEI components formed under electrolytes of varying salt concentrations. We find that, regardless of salt concentration, a conversion of initially deposited lithium ethylene dicarbonate to monocarbonates (likely lithium ethylene monocarbonate) and noncarbonate species occurs, and the extent of this conversion increases with electrolyte aging. We additionally demonstrate that as the concentration increases (up to 2.0 M LiPF6), the SEI becomes progressively thinner with more LiF and less solid carbonates deposited. Finally, we reveal that less dead lithium formation and less solid carbonate deposition occur during prolonged fast charging for higher-concentration electrolytes. Because of the advantages imparted by a thinner SEI, the onset state of charge for lithium plating for the 2.0 M electrolyte is later than that predicted by a standard electrochemical model, underscoring the importance of explicit SEI effects in future electrochemical models.

Original languageAmerican English
Pages (from-to)2734-2744
Number of pages11
JournalACS Energy Letters
Volume7
Issue number8
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.

NREL Publication Number

  • NREL/JA-5700-80769

Keywords

  • batteries
  • fast charge
  • graphite
  • lithium plating
  • lithium-ion
  • solid-electrolyte interface (SEI)

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