Mechanical properties of amorphous LixSi alloys: A reactive force field study

Feifei Fan, Shan Huang, Hui Yang, Muralikrishna Raju, Dibakar Datta, Vivek B. Shenoy, Adri C.T. Van Duin, Sulin Zhang, Ting Zhu

Research output: Contribution to journalArticle

75 Scopus citations

Abstract

Silicon is a high-capacity anode material for lithium-ion batteries. Electrochemical cycling of Si electrodes usually produces amorphous Li xSi (a-LixSi) alloys at room temperature. Despite intensive investigation of the electrochemical behaviors of a-LixSi alloys, their mechanical properties and underlying atomistic mechanisms remain largely unexplored. Here we perform molecular dynamics simulations to characterize the mechanical properties of a-LixSi with a newly developed reactive force field (ReaxFF). We compute the yield and fracture strengths of a-LixSi alloys under a variety of chemomechanical loading conditions, including the constrained thin-film lithiation, biaxial compression, uniaxial tension and compression. Effects of loading sequence and stress state are investigated to correlate the mechanical responses with the dominant atomic bonding, featuring a transition from the covalent to the metallic glass characteristics with increasing Li concentration. The results provide mechanistic insights for interpreting experiments, understanding properties and designing new experiments on a-LixSi alloys, which are essential to the development of durable Si electrodes for high-performance lithium-ion batteries.

Original languageEnglish (US)
Article number074002
JournalModelling and Simulation in Materials Science and Engineering
Volume21
Issue number7
DOIs
StatePublished - Oct 1 2013

All Science Journal Classification (ASJC) codes

  • Modeling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Computer Science Applications

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