Few-Layer Graphene Island Seeding for Dendrite-Free Li Metal Electrodes

Hee Kook Kang, Sang Gil Woo, Jae Hun Kim, Ji Sang Yu, Seong Rae Lee, Young Jun Kim

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

Li metal batteries such as Li-air and Li-S systems have increasingly attracted the attention of researchers because of their high energy densities, which are enhanced by the use of Li metal negative electrodes. However, poor cycle efficiency and safety concerns, which are mainly related to dendritic Li growth during cycling, need to be addressed. Here we propose a solution to the Li dendrite problems. We distributed chemically prepared nitrogen-doped few-layer graphene (N-FLG) sheets on Cu substrates to create island structures. The island-type FLG on the Cu electrode was prepared via spin-coating using slurries that included a polymer binder. When the electrode was used for Li deposition, Li ions were first inserted into the graphene layers. Then, Li metal nucleation occurred at the N-FLG sheets owing to their high electrical conductivity; meanwhile, an insulating polymer layer on the Cu prevented the growth of metallic Li there. Lastly, Li metal grew from the edges of N-FLG sheets in both the lateral and vertical direction, and Li metal deposits filled the gaps between the N-FLG islands as well as covering the remainder of the electrode surface. Thus, stable cycling with flat voltage profiles was demonstrated over 100 cycles at a current density of 2 mA cm-2. The materials and electrochemical characterization results highlight the effectiveness of this method, which paves the way for the development of robust, dendrite-free Li metal electrodes.

Original languageEnglish
Pages (from-to)26895-26901
Number of pages7
JournalACS Applied Materials and Interfaces
Volume8
Issue number40
DOIs
Publication statusPublished - 2016 Oct 12

Keywords

  • dendrites
  • graphene islands
  • lateral growth
  • Li metal batteries
  • nucleation seeds

ASJC Scopus subject areas

  • Materials Science(all)

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