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An XPS Study of Electrolytes for Li-Ion Batteries in Full Cell LNMO vs Si/Graphite

Abstract

Two different types of electrolytes (co-solvent and multi-salt) are tested for use in high voltage LiNi0.5Mn1.5O4||Si/graphite full cells and compared against a carbonate-based standard LiPF6 containing electrolyte (baseline). Ex situ postmortem XPS analysis on both anodes and cathodes over the life span of the cells reveals a continuously growing SEI and CEI for the baseline electrolyte. The cells cycled in the co-solvent electrolyte exhibited a relatively thick and long-term stable CEI (on LNMO), while a slowly growing SEI was determined to form on the Si/graphite. The multi-salt electrolyte offers more inorganic-rich SEI/CEI while also forming the thinnest SEI/CEI observed in this study. Cross-talk is identified in the baseline electrolyte cell, where Si is detected on the cathode, and Mn is detected on the anode. Both the multi-salt and co-solvent electrolytes are observed to substantially reduce this cross-talk, where the co-solvent is found to be the most effective. In addition, Al corrosion is detected for the multi-salt electrolyte mainly at its end-of-life stage, where Al can be found on both the anode and cathode. Although the co-solvent electrolyte offers superior interface properties in terms of the limitation of cross-talk, the multi-salt electrolyte offers the best overall performance, suggesting that interface thickness plays a superior role compared to cross-talk. Together with their electrochemical cycling performance, the results suggest that multi-salt electrolyte provides a better long-term passivation of the electrodes for high-voltage cells.
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Category

Academic article

Language

English

Author(s)

  • Raheleh Azmi
  • Fredrik Lindgren
  • Killian Stokes-Rodriguez
  • Mihaela Buga
  • Cosmin Ungureanu
  • Tom Gouveia
  • Ida Christensen
  • Shubhadeep Pal
  • Alexandru Vlad
  • Alix Ladam
  • Kristina Edström
  • Maria Hahlin

Affiliation

  • SINTEF Industry / Sustainable Energy Technology
  • Uppsala University
  • Université catholique de Louvain
  • France
  • National University of Science and Technology POLITEHNICA Bucharest
  • National Research and Development Institute for Cryogenic and Isotopic Technologies (ICSI)
  • Diverse norske bedrifter og organisasjoner

Year

2024

Published in

ACS Applied Materials & Interfaces

ISSN

1944-8244

Volume

16

Issue

26

Page(s)

34266 - 34280

View this publication at Norwegian Research Information Repository