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 (C1F), the chair configuration is found to be energetically more stable than the boat one, while both C1F's exhibit semiconducting behavior due to the sp(3)-hybridized C atoms. For the half-fluorinated BLG (C2F), two configurations, namely, C2F-1 and C2F-3, are energetically favored. The electronic characteristics of the half-fluorinated BLG depend sensitively on its atomic configurations. The C2F-1 exhibits a semiconducting nature, while C2F-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.