Structural and electrochemical study of the reaction of lithium with silicon nanowires

Candace K. Chan, Riccardo Ruffo, Seung Sae Hong, Robert A. Huggins, Yi Cui

Research output: Contribution to journalArticle

252 Citations (Scopus)

Abstract

The structural transformations of silicon nanowires when cycled against lithium were evaluated using electrochemical potential spectroscopy and galvanostatic cycling. During the charge, the nanowires alloy with lithium to form an amorphous LixSi compound. At potentials <50 mV, a structural transformation occurs. In studies on micron-sized particles previously reported in the literature, this transformation is a crystallization to a metastable Li15Si4 phase. X-ray diffraction measurements on the Si nanowires, however, show that they are amorphous, suggesting that a different amorphous phase (LiySi) is formed. Lithium is removed from this phase in the discharge to form amorphous silicon. We have found that limiting the voltage in the charge to 70 mV results in improved efficiency and cyclability compared to charging to 10 mV. This improvement is due to the suppression of the transformation at low potentials, which alloys for reversible cycling of amorphous silicon nanowires.

Original languageEnglish
Pages (from-to)34-39
Number of pages6
JournalJournal of Power Sources
Volume189
Issue number1
DOIs
Publication statusPublished - Apr 1 2009

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Keywords

  • Anode
  • Lithium-ion battery
  • Phase transformation
  • Silicon nanowire

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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