Brittle-to-ductile transition of lithiated silicon electrodes: Crazing to stable nanopore growth

Haoran Wang, Xueju Wang, Shuman Xia, Huck Beng Chew

Research output: Contribution to journalArticlepeer-review

Abstract

Using first principle calculations, we uncover the underlying mechanisms explaining the brittle-to-ductile transition of LixSi electrodes in lithium ion batteries with increasing Li content. We show that plasticity initiates at x = ∼ 0.5 with the formation of a craze-like network of nanopores separated by Si-Si bonds, while subsequent failure is still brittle-like with the breaking of Si-Si bonds. Transition to ductile behavior occurs at x ≥ 1 due to the increased density of highly stretchable Li-Li bonds, which delays nanopore formation and stabilizes nanopore growth. Collapse of the nanopores during unloading of the LixSi alloys leads to significant strain recovery.

Original languageEnglish (US)
Article number104703
JournalJournal of Chemical Physics
Volume143
Issue number10
DOIs
StatePublished - Sep 14 2015

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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