Lithiation of Silica through Partial Reduction

Chunmei Ban, Branden B. Kappes, Qiang Xu, Chaiwat Engtrakul, Cristian V. Ciobanu, Anne C. Dillon, Yufeng Zhao

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57 Scopus Citations

Abstract

We demonstrate the reversible lithiation of SiO 2 up to 2/3 Li per Si, and propose a mechanism for it based on molecular dynamics and density functional theory simulations. Our calculations show that neither interstitial Li (no reduction), nor the formation of Li 2O clusters and Si-Si bonds (full reduction) are energetically favorable. Rather, two Li effectively break a Si-O bond and become stabilized by oxygen, thus partially reducing the SiO 2 anode: this leads to increased anode capacity when the reduction occurs at the Si/SiO 2 interface. The resulting Li xSiO 2 (x < 2/3) compounds have band-gaps in the range of 2.0-3.4 eV.

Original languageAmerican English
Article number243905
Number of pages4
JournalApplied Physics Letters
Volume100
Issue number24
DOIs
StatePublished - 11 Jun 2012

NREL Publication Number

  • NREL/JA-5900-55251

Keywords

  • anodes
  • capacity
  • electrodes
  • energy gap
  • functionals
  • interstitials
  • lithium
  • molecular dynamics method
  • oxygen
  • reaction kinetics
  • silica
  • silicon compounds

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