Poor Man's Atomic Layer Deposition of LiF for Additive-Free Growth of Lithium Columns

Wesley Chang, Jeung Hun Park, Daniel Artemus Steingart

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Lithium metal is an ideal material for high-energy, cost-effective rechargeable energy storage systems. The thermodynamically unfavorable solid-liquid interface between the lithium metal and organic electrolyte necessitates the formation of an interlayer (SEI) which is known to have significant impact on lithium morphologies. Less well understood is the impact of the current collector substrate on the morphology of electrodeposited lithium. Here we report on the morphology of electrodeposited lithium as a function of the chemical pretreatments of the working electrode. We find that a copper substrate pretreatment with acidic solutions (sulfuric, oxalic, or acetic acid) results in the deposition of close-packed lithium columns with a uniform diameter. A controlled study of the pre-electrodeposited copper surface indicates that the formation of a 5-8 nm thick LiF protective layer on copper substrate from a chemical reaction between adsorbed surface water layer in acidic solutions and LiPF6 electrolyte is the key process in the electrochemical growth of lithium columns. We anticipate that this simple chemical approach can be generalized as a scalable, low-cost, additive-free substrate treatment method for depositing a LiF protective layer, broadly applicable in the development of uniform lithium films.

Original languageEnglish (US)
Pages (from-to)7066-7074
Number of pages9
JournalNano Letters
Volume18
Issue number11
DOIs
StatePublished - Nov 14 2018

All Science Journal Classification (ASJC) codes

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

Keywords

  • LiF layer
  • Lithium metal anode
  • close packed columnar growth
  • copper current collector
  • electrodeposition
  • surface treatment

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