One-minute deposition of micrometre-thick porous Si-Cu anodes with compositional gradients on Cu current collectors for lithium secondary batteries

Jungho Lee, Kei Hasegawa, Toshiyuki Momma, Tetsuya Osaka, Suguru Noda

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We report micrometre-thick porous Si-Cu anodes that are rapidly co-deposited on Cu current collectors in 1 min. This rapid deposition is realized by heating Si and Cu powders to ∼2000 °C and elevating their vapour pressures, while the porous and amorphous anode structure is realized by keeping the substrates at 100 °C. The films spontaneously form a 2-4.5-μm-thick composition gradient that changes from a Cu-rich region at the bottom to a Si-rich region at the top of the film, because of the higher vapour pressure for Cu than Si. A small addition of 5 wt% Cu to the Si source enhances the cycle performance of the film remarkably in a half-cell test, yielding a gravimetric capacity of 1250 mAh g<inf>film</inf><sup>-1</sup>, a volumetric capacity of 1956 mAh cm<inf>film</inf><sup>-3</sup>, and an areal capacity of 0.96 mAh cm<inf>anode</inf><sup>-2</sup> at the 100th cycle. However, excess addition of Cu causes partial Si crystallization in the films, which results in poorer cycle performance. While further improvement is needed, this rapid vapour deposition method yields Si-Cu films with compositional gradients on Cu current collectors in 1 min using inexpensive and safe Si and Cu powder sources, and is attractive for practical Si-based anode fabrication.

Original languageEnglish
Pages (from-to)540-550
Number of pages11
JournalJournal of Power Sources
Volume286
DOIs
Publication statusPublished - 2015 Jul 15

Keywords

  • Anodes
  • Compositional gradients
  • Lithium secondary batteries
  • Physical vapour deposition
  • Porous films
  • Silicon-copper alloy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment
  • Physical and Theoretical Chemistry

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