Li segregation induces structure and strength changes at the amorphous Si/Cu interface

Maria E. Stournara, Xingcheng Xiao, Yue Qi, Priya Johari, Peng Lu, Brian W. Sheldon, Huajian Gao, Vivek B. Shenoy

Research output: Contribution to journalArticle

  • 41 Citations

Abstract

The study of interfacial properties, especially of their change upon lithiation, is a fundamentally significant and challenging topic in designing heterogeneous nanostructured electrodes for lithium ion batteries. This issue becomes more intriguing for Si electrodes, whose ultrahigh capacity is accompanied by large volume expansion and mechanical stress, threatening with delamination of silicon from the metal current collector and failure of the electrode. Instead of inferring interfacial properties from experiments, in this work, we have combined density functional theory (DFT) and ab initio molecular dynamics (AIMD) calculations with time-of-flight secondary ion mass spectrometry (TOF-SIMS) measurements of the lithium depth profile, to study the effect of lithiation on the a-Si/Cu interface. Our results clearly demonstrate Li segregation at the lithiated a-Si/Cu interface (more than 20% compared to the bulk concentration). The segregation of Li is responsible for a small decrease (up to 16%) of the adhesion strength and a dramatic reduction (by one order of magnitude) of the sliding resistance of the fully lithiated a-Si/Cu interface. Our results suggest that this almost frictionless sliding stems from the change of the bonding nature at the interface with increasing lithium content, from directional covalent bonding to uniform metallic. These findings are an essential first step toward an in-depth understanding of the role of lithiation on the a-Si/Cu interface, which may contribute in the development of quantitative electrochemical mechanical models and the design of nonfracture-and-always-connected heterogeneous nanostructured Si electrodes.

LanguageEnglish (US)
Pages4759-4768
Number of pages10
JournalNano Letters
Volume13
Issue number10
DOIs
StatePublished - 2013

Profile

Electrodes
Lithium
electrodes
lithium
sliding
Bond strength (materials)
Silicon
Secondary ion mass spectrometry
Delamination
Density functional theory
Molecular dynamics
stems
Metals
accumulators
secondary ion mass spectrometry
electric batteries
adhesion
molecular dynamics
density functional theory
expansion

Keywords

  • density functional theory
  • interface
  • Li-ion battery
  • molecular dynamics
  • Si anode

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Stournara, M. E., Xiao, X., Qi, Y., Johari, P., Lu, P., Sheldon, B. W., ... Shenoy, V. B. (2013). Li segregation induces structure and strength changes at the amorphous Si/Cu interface. Nano Letters, 13(10), 4759-4768. DOI: 10.1021/nl402353k

Li segregation induces structure and strength changes at the amorphous Si/Cu interface. / Stournara, Maria E.; Xiao, Xingcheng; Qi, Yue; Johari, Priya; Lu, Peng; Sheldon, Brian W.; Gao, Huajian; Shenoy, Vivek B.

In: Nano Letters, Vol. 13, No. 10, 2013, p. 4759-4768.

Research output: Contribution to journalArticle

Stournara, ME, Xiao, X, Qi, Y, Johari, P, Lu, P, Sheldon, BW, Gao, H & Shenoy, VB 2013, 'Li segregation induces structure and strength changes at the amorphous Si/Cu interface' Nano Letters, vol 13, no. 10, pp. 4759-4768. DOI: 10.1021/nl402353k
Stournara ME, Xiao X, Qi Y, Johari P, Lu P, Sheldon BW et al. Li segregation induces structure and strength changes at the amorphous Si/Cu interface. Nano Letters. 2013;13(10):4759-4768. Available from, DOI: 10.1021/nl402353k
Stournara, Maria E. ; Xiao, Xingcheng ; Qi, Yue ; Johari, Priya ; Lu, Peng ; Sheldon, Brian W. ; Gao, Huajian ; Shenoy, Vivek B./ Li segregation induces structure and strength changes at the amorphous Si/Cu interface. In: Nano Letters. 2013 ; Vol. 13, No. 10. pp. 4759-4768
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