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: Research - peer-reviewArticle

    • 35 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
    electrodes
    lithium
    Lithium
    sliding
    Bond strength (materials)
    Silicon
    Secondary ion mass spectrometry
    Delamination
    Density functional theory
    Molecular dynamics
    Metals
    Experiments
    Lithium-ion batteries
    stems
    accumulators
    secondary ion mass spectrometry
    electric batteries
    adhesion
    molecular dynamics

    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: Research - peer-reviewArticle

    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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