Silicon nanowire degradation and stabilization during lithium cycling by SEI layer formation

Jeong Hyun Cho, S. Tom Picraux

Research output: Contribution to journalArticlepeer-review

65 Scopus citations

Abstract

Silicon anodes are of great interest for advanced lithium-ion battery applications due to their order of magnitude higher energy capacity than graphite. Below a critical diameter, silicon nanowires enable the ∼300% volume expansion during lithiation without pulverization. However, their high surface-to-volume ratio is believed to contribute to fading of their capacity retention during cycling due to solid-electrolyte-interphase (SEI) growth on surfaces. To better understand this issue, previous studies have examined the composition and morphology of the SEI layers. Here we report direct measurements of the reduction in silicon nanowire diameter with number of cycles due to SEI formation. The results reveal significantly greater Si loss near the nanowire base. From the change in silicon volume we can accurately predict the measured specific capacity reduction for silicon nanowire half cells. The enhanced Si loss near the nanowire/metal current collector interface suggests new strategies for stabilizing nanowires for long cycle life performance.

Original languageEnglish (US)
Pages (from-to)3088-3095
Number of pages8
JournalNano letters
Volume14
Issue number6
DOIs
StatePublished - Jun 11 2014

Keywords

  • Lithium-ion battery
  • current density
  • fracture
  • silicon nanowire
  • solid electrolyte interphase (SEI)
  • surface morphology

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