Chemical Bonding of Partially Fluorinated Graphene

Abstract

Understanding the interactions of graphene and chemical additives is crucial to achieve control over chemically modified graphene materials. Here, density functional theory and experiments are used to elucidate the chemical bonding of partially fluorinated graphene. This material includes F−C bonds whose ionicity varies depending upon local concentration and structure. Three bonding states dominate. Single fluorine on graphene forms a semi-ionic bond with a C atom in an sp 2 configuration. Fluorine in highly stable domains of poly(carbon fluoride) consists of covalent F−C bonds alternating in ortho position one to another on both sides of graphene. Fluorine in regions of poly(tetracarbon fluoride) has F species on one side of graphene in para position one to another, and F−C bonds with a character intermediate between the semi-ionic and covalent. Such variability in chemical bonding could be exploited to tailor fluorinated graphene materials to achieve a variety of properties.

Fluorination of MXene by Elemental F2 as Electrode Material for Lithium‐Ion Batteries

“…If MXene is attacked by F 2 , there is chemisorption of F onto the carbon surface and intercalation of F between the layers. The nature of the F−C bond is dependent on the concentration of F . It is observed from the F 1s XPS spectra (Figure c) that the HF‐treated Ti 3 AlC 2 (MXene) contains a high concentration of F LD −C, which has a semi‐ionic bond, and with an increase in the fluorination time the F LD −C concentration decreases and the F HD −C, containing a covalent bond, increases until no observable F LD −C peak remains after 24 h fluorination (FMX24).…”

“…[1,24,41,43,44] The fluorination mechanism of graphene (and related graphitic carbons) has been reported as well as that of HF-treated Ti 3 AlC 2 .H owever,t he direct fluorination (by elemental F 2 ) mechanism of MXene has not been studied before.I fM Xene is attacked by F 2 ,t here is chemisorption of Fo nto the carbon surfacea nd intercalation of Fb etween the layers. The nature of the FÀCb ondi sdependento nt he concentration of F. [45] It is observed from the F1sX PS spectra (Figure 3c)t hat the HFtreated Ti 3 AlC 2 (MXene) contains ah igh concentration of F LD À C, which has asemi-ionicbond, and with an increase in the fluorination time the F LD ÀCc oncentration decreases and the F HD À C, containing ac ovalent bond, increases until no observable F LD ÀCp eak remains after 24 hf luorination (FMX24). The fluorination process of carbon transpires at the sp 3 Cs ites of the MXene, during which the oxygen-containing groups are substi- www.chemsuschem.org tuted by Fa toms.…”

Nitrogen and fluorine co-doped graphene as a high-performance anode material for lithium-ion batteries

“…S3b-d †). 43,55,58 These peaks can also be also in FG (Fig. S3a †), which further proves most of the oxygen functional groups are removed during the hydrothermal process.…”

Decomposition of Fluorinated Graphene under Heat Treatment

“…As the annealing temperature was increased to 600 K, the HE component of F 1s spectra was found to subsequently shift to a higher binding energy by about 0.5 eV (Figure A). This shift indicates a decrease in the F−C bond length, which is directly connected with an increase in covalency of the F−C bonding state . A further increase in annealing temperature did not influence significantly the binding energy of the HE component of the F 1s spectra.…”