Depth profiling the solid electrolyte interphase on lithium titanate (Li4Ti5O12) using synchrotron-based photoelectron spectroscopy

Tim Nordh, Reza Younesi, Daniel Brandell, Kristina Edström

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The presence of a surface layer on lithium titanate (Li4Ti5O12, LTO) anodes, which has been a topic of debate in scientific literature, is here investigated with tunable high surface sensitive synchrotron-based photoelectron spectroscopy (PES) to obtain a reliable depth profile of the interphase. Li||LTO cells with electrolytes consisting of 1 M lithium hexafluorophosphate dissolved in ethylene carbonate:diethyl carbonate (LiPF6 in EC:DEC) were cycled in two different voltage windows of 1.0-2.0 V and 1.4-2.0 V. LTO electrodes were characterized after 5 and 100 cycles. Also the pristine electrode as such, and an electrode soaked in the electrolyte were analyzed by varying the photon energies enabling depth profiling of the outermost surface layer. The main components of the surface layer were found to be ethers, P-O containing compounds, and lithium fluoride.
Original languageEnglish
JournalJournal of Power Sources
Volume294
Pages (from-to)173-179
Number of pages7
ISSN0378-7753
DOIs
Publication statusPublished - 2015

Keywords

  • Li-ion batteries
  • LTO
  • PES
  • SEI
  • Surface layer
  • XPS
  • Depth profiling
  • Electrodes
  • Electrolytes
  • Ethylene
  • Lithium
  • Lithium compounds
  • Photoelectron spectroscopy
  • Photoelectrons
  • Photons
  • Solid electrolytes
  • Titanium compounds
  • X ray photoelectron spectroscopy
  • Surface layers
  • Lithium-ion batteries

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