Structural Stability and Electronic and Magnetic Properties of Fluorinated Bilayer Graphene

As a first step toward gaining a microscopic understanding of the fluorination of bilayer graphene (BLG) as the electrode material for lithium-ion batteries, the structural stability and electronic and magnetic properties of fluorinated BLG have been investigated using density functional theory. For the fully fluorinated BLG (C 1 F), the chair configuration is found to be energetically more stable than the boat one, while both C 1 F’s exhibit semiconducting behavior due to the sp 3 -hybridized C atoms. For the half-fluorinated BLG (C 2 F), two configurations, namely, C 2 F-1 and C 2 F-3, are energetically favored. The electronic characteristics of the half-fluorinated BLG depend sensitively on its atomic configurations. The C 2 F-1 exhibits a semiconducting nature, while C 2 F-3 is metallic. In addition, the presence of a fluorine vacancy defect in fluorinated BLG is also studied. It is manifested that the nonfluorinated C atoms (sp 2 -hybridized) in the fluorinated BLGs are of remarkable significance in improving their electrical conductivity.