Daniel Claves

Spectroscopic study of fluorinated carbon nanostructures

Fluorocarbon nanostructures possess an outer halogenated crown that plays the role of an interface towards their environment and whose properties are then crucial for anticipating the integration of the latter materials in nanotechnology processes. Therefore, the result of fluorine addition to nanocarbon frames has been investigated here with the help of IR and XPS spectroscopies, and the role played by the pristine lattice curvature and the addend’s addition scheme on the physicochemical characteristics of this outermost shell is experimentally established. The relevant paradigm of supposedly ionocovalent C–F terminations in these nanomaterials is shown to be obsolete.

Transition metals oxyfluorides intercalated into graphite : new synthesis route and electrochemical properties

Abstract A fluorine–oxygen exchange has been realized in several transition metals fluorides (NbF 5 , MoF 6 , WF 6 ) graphite intercalation compounds (GICs) and oxyfluorides (VOF 3 , VOF 3 -CrO 2 F 2 ) GICs using hexamethyldisiloxane. The reaction products were characterized by X-ray diffraction, thermogravimetric analysis, FT-IR and 19 F NMR spectroscopy. The electrochemical performances of these novel materials were tested in liquid electrolyte conditions.

C60-Inorganic fluorides intercalation compounds: some formation condition data and their electrochemical behavior in lithium cell systems

Abstract An overview of our contribution to the worldwide work on fluorinated carbons and inorganic fluorides-based intercalation compounds is presented. Recent results concerning the intercalation of NbF 5 , TaF 5 and TiF 4 into the C 60 lattice and the behavior of a wide series of C 60 (MF n ) x phases used as cathode materials in lithium batteries are described.

Study of the reactivity of chalcogen hexafluorides with graphite

Abstract The intercalation reaction of chalcogen hexafluorides, EF6 (E=S, Se, Te), with graphite was investigated. It occured only under a fluorine atmosphere and first stage intercalation compounds were obtained with TeF6 or SeF6, as well as a partial graphite fluorination. SF6 did not intercalate but catalyzed the complete fluorination of graphite. All compounds were characterized by X-ray diffraction, thermogravimetric analysis, infrared and 19 F NMR spectroscopies. Entities, such as TeF6 and SeF6 were identified. Others, such as EF7−, EF82−, …, and possible SeFn polymeric forms could exist. In all cases, the presence of fluorinated graphite was found.