From Ab initio calculations to multiscale design of Si/C core-shell particles for Li-ion anodes

Maria E. Stournara, Yue Qi, Vivek B. Shenoy

Research output: Contribution to journalArticle

  • 16 Citations

Abstract

The design of novel Si-enhanced nanocomposite electrodes that will successfully mitigate mechanical and chemical degradation is becoming increasingly important for next generation Li-ion batteries. Recently Si/C hollow core-shell nanoparticles were proposed as a promising anode architecture, which can successfully sustain thousands of cycles with high Coulombic efficiency. As the structural integrity and functionality of these heterogeneous Si materials depend on the strength and fracture energy of the active materials, an in-depth understanding of the interface and their intrinsic mechanical properties, such as fracture strength and debonding, becomes critical for the successful design of such and similar composites. Here, we first perform ab initio simulations to calculate these properties for lithiated a-Si/a-C interface structures and combine these results with linear elasticity expressions to model conditions that will avert fracture and debonding in these heterostructures. We find that the a-Si/a-C interface retains good adhesion even at high stages of lithiation. For average lithiated structures, we predict that the strong Si-C bonding averts fracture at the interface; instead, the structure ruptures within lithiated a-Si. From the calculated values and linear elastic fracture mechanics, we then construct a continuum level diagram, which outlines the safe regimes of operation in terms of the core and shell thickness and the state of charge. We believe that this multiscale approach can serve as a foundation for developing quantitative failure models and for subsequent development of flaw-tolerant anode architectures.

LanguageEnglish (US)
Pages2140-2149
Number of pages10
JournalNano Letters
Volume14
Issue number4
DOIs
StatePublished - Apr 9 2014

Profile

Debonding
Anodes
anodes
Ions
Fracture energy
Structural integrity
Fracture mechanics
Heterojunctions
Fracture toughness
Elasticity
Nanocomposites
ions
Adhesion
Nanoparticles
Degradation
Mechanical properties
Defects
Electrodes
fracture mechanics
Composite materials

Keywords

  • ab initio calculations
  • continuum modeling
  • fracture
  • Li-ion battery
  • Si/C composite anode
  • Si/C interface strength

ASJC Scopus subject areas

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

Cite this

From Ab initio calculations to multiscale design of Si/C core-shell particles for Li-ion anodes. / Stournara, Maria E.; Qi, Yue; Shenoy, Vivek B.

In: Nano Letters, Vol. 14, No. 4, 09.04.2014, p. 2140-2149.

Research output: Contribution to journalArticle

Stournara, Maria E. ; Qi, Yue ; Shenoy, Vivek B./ From Ab initio calculations to multiscale design of Si/C core-shell particles for Li-ion anodes. In: Nano Letters. 2014 ; Vol. 14, No. 4. pp. 2140-2149
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