Design of Nanostructured Heterogeneous Solid Ionic Coatings through a Multiscale Defect Model

Jie Pan, Qinglin Zhang, Xingcheng Xiao, Yang Tse Cheng, Yue Qi

    Research output: Research - peer-reviewArticle

    • 5 Citations

    Abstract

    Understanding of the electrical conduction, that is, ionic and electronic conduction, through the solid electrolyte interphase (SEI) is critical to the design of durable lithium-ion batteries (LIBs) with high rate capability and long life. It is believed that an ideal SEI should not only be an ionic conductor, but also an electronic insulator. In this study, we present a theoretical design of an artificial SEI consisting of lithium fluoride (LiF) and lithium carbonate (Li2CO3) on a LIB anode based on a newly developed density functional theory (DFT) informed space charge model. We demonstrate that the migration of lattice Li ions from LiF phase to form Li interstitials in Li2CO3 is energetically favorable near the LiF/Li2CO3 interface. At equilibrium, this interfacial defect reaction establishes a space charge potential across the interface, which causes the accumulation of ionic carriers but the depletion of electronic carriers near the LiF/Li2CO3 interface. To utilize this space charge effect, we propose a computationally designed, nanostructured artificial SEI structure with high density of interfaces of LiF and Li2CO3 perpendicular to the electrode. On the basis of this structure, the influences of grain size and volume ratio of the two phases were studied. Our results reveal that reducing the grain size of Li2CO3 in the nanostructured composite can promote ionic carriers and increase the ionic conductivity through the composite SEI by orders of magnitude. At the same time, the electronic conductivity is reduced due to electron depletion near the LiF/Li2CO3 interface. Furthermore, an optimal volume fraction that ensures high ionic and low electronic conduction was predicted.

    LanguageEnglish (US)
    Pages5687-5693
    Number of pages7
    JournalACS Applied Materials and Interfaces
    Volume8
    Issue number8
    DOIs
    StatePublished - Mar 2 2016

    Profile

    Carbon Monoxide
    Coatings
    Defects
    Lithium
    lithium fluoride
    Solid electrolytes
    Electric space charge
    Composite materials
    Lithium-ion batteries
    Lithium Carbonate
    Ionic conductivity
    Density functional theory
    Volume fraction
    Anodes
    Ions
    Electrodes
    Electrons
    Carbonates

    Keywords

    • defect
    • density functional theory
    • heterogeneous interface
    • ionic conduction
    • solid electrolyte interphase
    • space charge

    ASJC Scopus subject areas

    • Materials Science(all)

    Cite this

    Design of Nanostructured Heterogeneous Solid Ionic Coatings through a Multiscale Defect Model. / Pan, Jie; Zhang, Qinglin; Xiao, Xingcheng; Cheng, Yang Tse; Qi, Yue.

    In: ACS Applied Materials and Interfaces, Vol. 8, No. 8, 02.03.2016, p. 5687-5693.

    Research output: Research - peer-reviewArticle

    Pan, Jie ; Zhang, Qinglin ; Xiao, Xingcheng ; Cheng, Yang Tse ; Qi, Yue. / Design of Nanostructured Heterogeneous Solid Ionic Coatings through a Multiscale Defect Model. In: ACS Applied Materials and Interfaces. 2016 ; Vol. 8, No. 8. pp. 5687-5693
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