title: Few-Layer Graphene Island Seeding for Dendrite-Free Li Metal Electrodes.
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.
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute , Seongnam, Gyeonggi 13509, Republic of Korea.|Department of Materials Science and Engineering, Korea University , Seoul 02841, Republic of Korea.
authors.forename: Hee-Kook
authors.initials: HK
authors.lastname: Kang
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute , Seongnam, Gyeonggi 13509, Republic of Korea.
authors.forename: Sang-Gil
authors.initials: SG
authors.lastname: Woo
authors.affiliation: School of Advanced Materials Engineering, Kookmin University , Seoul 02707, Republic of Korea.
authors.forename: Jae-Hun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute , Seongnam, Gyeonggi 13509, Republic of Korea.
authors.forename: Ji-Sang
authors.initials: JS
authors.lastname: Yu
authors.affiliation: Department of Materials Science and Engineering, Korea University , Seoul 02841, Republic of Korea.
authors.forename: Seong-Rae
authors.initials: SR
authors.lastname: Lee
authors.affiliation: Advanced Batteries Research Center, Korea Electronics Technology Institute , Seongnam, Gyeonggi 13509, Republic of Korea.|SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University , Gyeonggi 16419, Republic of Korea.
authors.forename: Young-Jun
authors.initials: YJ
authors.lastname: Kim
keywords: Li metal batteries; dendrites; graphene islands; lateral growth; nucleation seeds