Assessing Electrolyte Fluorination Impact on Calendar Aging of Blended Silicon-Graphite Lithium-Ion Cells Using Potentiostatic Holds

Ankit Verma, Maxwell Schulze, Andrew Colclasure, Marco-Tulio Rodrigues, Stephen Trask, Krzysztof Pupek, Christopher Johnson, Daniel Abraham

Research output: Contribution to journalArticlepeer-review

1 Scopus Citations

Abstract

Silicon-based lithium-ion batteries have started to meet cycle life metrics, but they exhibit poor calendar life. Here, electrolyte fluorination impact on calendar fade of blended silicon-graphite anodes is explored using a LiPF6 in EC:EMC:FEC electrolyte vs LiBOB in EC:EMC electrolyte. We utilize a combined experimental-modeling approach applying potentiostatic voltage holds (V-hold) to evaluate electrolyte suitability for calendar life in a shortened testing timeframe (∼2 months). Our theoretical framework deconvolutes the irreversible parasitic capacity losses (lithium lost to the solid electrolyte interphase) from the V-hold electrochemical data. Unfluorinated electrolyte (dominant LiBOB reduction) exhibits higher cell resistance as compared to fluorinated electrolyte (dominant FEC reduction). Both systems have similar irreversible capacities during the voltage hold duration with slower rate of parasitic capacity loss for the LiBOB system. Extrapolation of the parasitic losses to end of life capacity fade of 20% shows LiBOB electrolyte outperforming LiPF6 electrolyte in calendar life. The results demonstrate the applicability of the V-hold protocol as a rapid material screening tool providing semi-quantitative calendar lifetime estimates.

Original languageAmerican English
Article number070516
Number of pages13
JournalJournal of the Electrochemical Society
Volume170
Issue number7
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited

NREL Publication Number

  • NREL/JA-5700-86203

Keywords

  • calendar aging
  • fluorine-free electrolytes
  • fluorine-rich electrolytes
  • silicon
  • voltage-hold

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