Real-time observations of interfacial lithiation in a metal silicide thin film

Tim T. Fister, Brandon R. Long, Andrew A. Gewirth, Bing Shi, Lahsen Assoufid, Sang Soo Lee, Paul Fenter

Research output: Contribution to journalArticlepeer-review

Abstract

Interfacial reactions and phase transformations play a significant role in the capacity and reversibility of lithium batteries. Understanding interfacial structural changes is especially important in alloying or conversion reactions found in higher-capacity intermetallic or metal oxyfluoride systems. Using in-situ X-ray reflectivity, we observe the lithiation of a stratified chromium silicide film with sub-nanometer resolution as a model system for characterizing such lithiation mechanisms. In-situ X-ray reflectivity of the thin film reveals that the sample lithiates to form the 1 nm thick low-electron-density regions at the buried interfaces separating each phase at sufficiently low electrochemical potentials. The reflectivity also indicates a significant accumulation of lithium at the surface at potentials approaching 0 V vs Li/Li +. The lithiation on the surface is fully reversible, whereas that in the film is partially irreversible. The observed mechanism for interfacial lithiation is likely a general feature of intermetallic electrodes and could be optimized for higher surface area nanostructures.

Original languageEnglish (US)
Pages (from-to)22341-22345
Number of pages5
JournalJournal of Physical Chemistry C
Volume116
Issue number42
DOIs
StatePublished - Oct 25 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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