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The work reports a study of the processes of multilayer graphene (MLG) preparation using the action of microwave (MW) radiation on polyfluoridedicarbon intercalation compounds with general composition C2F·xR (R is chlorine trifluoride, acetone, acetonitrile, carbon tetrachloride, and benzene). Under the action of MW heating, these intercalation compounds undergo exfoliation (splitting) at temperature values that are 40–55% lower than in the case of traditional convective heating. It is shown that microwave heating increases the exfoliation degree and specific surface area of fluorinated graphite and decreases residual content of fluorine and chlorine in MLG. A key role in the process of MW exfoliation is due to the absorption of MW radiation by the polar dielectric intercalated into the interlayer space of fluorinated graphite. [ABSTRACT FROM AUTHOR]

Graphene materials including porous few-layered graphenes are under focus of scientific community today. The great attention towards them is caused by their remarkable properties. Here, we use two different fluorinated graphite intercalation compounds with different fluorine content in their matrices to prepare thermally exfoliated fluorinated graphites and to investigate them in terms of their structural, spectroscopic and electrochemical properties as materials for use in supercapacitors. A higher temperature of low-fluorinated graphenes preparation resulted in higher exfoliation degree and higher gravimetric capacitance in supercapacitor appliances. More dramatic leap of gravimetric capacitance was observed after a treatment in a concentrated acid mixture of graphene material samples prepared at the highest temperature of thermolysis with highest exposition time. [ABSTRACT FROM AUTHOR]

Few-layer graphene materials have been produced by decomposition of fluorinated graphite intercalated with acetonitrile (CH3CN) or isopropylamine ((CH3)2CHNH2) in the conditions of thermal shock. Electronic structure of the samples before and after exfoliation was studied using near-edge X-ray absorption fine structure and X-ray photoelectron spectroscopy. Analysis of the spectroscopic data revealed the same set of nitrogen species in both exfoliation products that indicates decomposition of the intercalated molecules to the atomic state. Most of the nitrogen atoms were incorporated at the edges of graphene layers in pyridinic and protonated nitrogen forms. A difference in the electrochemical performance of the graphene materials was related with the exfoliation degree and the defect density in the graphene layers. Schematic representation of a process of thermal exfoliation of acetonitrile-intercalated fluorinated graphite. [ABSTRACT FROM AUTHOR]

Fluorinated graphite intercalation compounds (FGICs) with acetonitrile C2F x · yCH3CN ( x = 0.92, 0.69, and 0.49) have been synthesized using a gaseous mixture of BrF3 and Br2 at room temperature and subsequent replacement of the reaction medium components on acetonitrile by isopiestic method. The change in functional composition and electronic structure of FGICs under annealing at 250-260 °C was studied by infrared, X-ray photoelectron, and near-edge X-ray absorption fine structure spectroscopy (NEXAFS) methods. Analysis of the data revealed interaction of acetonitrile with a C2F x matrix. The X-ray spectra detected formation of new nitrogen species attributed to two-coordinated and mono hydrogenated three-coordinated atoms. Mechanism of nitrogen incorporation in the fluorinated graphene layers was proposed. Schematic structure of graphite fluoride C2F x intercalated with acetonitrile and NEXAFS N K-edge spectrum of C2F0.69 · 0.137CH3CN before and after annealing at 250 °C. [ABSTRACT FROM AUTHOR]

Abstract: Fluorine compounds are quite useful as energy conversion materials, in particular as primary and secondary lithium battery materials. Primary lithium battery with graphite fluoride cathode was commercialized in 1973, based on the research on graphite fluoride. Since then, it has been shown that fluorine compounds are useful and attractive materials for lithium batteries. The present account paper reports the historical aspects and update topics on fluorine compounds such as graphite fluorides, fluorine–graphite intercalation compounds and organo-fluorine compounds as energy conversion materials. Surface modification by fluorine is also reported. [Copyright &y& Elsevier]

We have synthesized (CFBr · yG) intercalation compounds with (CFBr) as a host and G (dichloromethane, chloroform, carbon tetrachloride, and dichloroethane) as a guest ( x and y are stoichiometric coefficients). The behavior of the functional groups in the guest and host subsystems has been studied by IR spectroscopy. We have examined the influence of the degree of fluorination of the polymer host (0.5 < x < 1.0) and the nature of the guest on the vibrational frequencies of the C-F and C-Cl bonds. [ABSTRACT FROM AUTHOR]

Abstract: A series of new highly exfoliated graphites were synthesized from fluorinated graphite intercalation compounds of compositions C2F·xR (R=ClF3, (CH3)2CO, CH3CN, C6H6, CCl4). The exfoliation degree of these materials reaches more than 2000 times, indicating a significantly higher exfoliated state than observed for the conventional expanded graphites derived from graphite bisulphate or nitrate. These exfoliated graphites have increased interlayer distances, specific surface areas as high as 170–370m2/g, low bulk densities of 0.4–0.7g/L, and good sorption capacities towards a range of organic and inorganic liquids. The influence of the nature of the intercalated molecules on the properties of the exfoliated graphite is discussed. [Copyright &y& Elsevier]

Thermal dissociation processes for acetonitrile inclusion compounds based on the polymer fluorographite host matrix CFBr· yCHCN, where x = 0.49-0.92, y = 0.174-0.285, are investigated. Thermodynamic parameters (Δ H°, Δ S°, Δ G°) for deintercalation of the compounds of the first filling step into the compounds of the second step and gaseous guest within temperature range 294-352 K were determined. The effect of the host matrix fluorination degree on the thermodynamic characteristics of the studied processes is demonstrated. [ABSTRACT FROM AUTHOR]

Inclusion compounds (intercalates) of fluorinated graphite matrix with acetone (CFBr· y(CH)CO, x = 0.49, 0.69, 0.87, 0.92, z ≈ 0.01) were prepared by guest substitution from acetonitrile to acetone. The kinetics of the thermal decomposition (the first stage of filling → the second stage of filling) was studied under isothermal conditions at 292-313 K. The relationship of the host matrices structure with inclusion compounds thermal properties and kinetic parameters is discussed. [ABSTRACT FROM AUTHOR]

The reaction mechanisms of a stage-1 fluorine–graphite intercalation compound (GIC), C2.5F, with 0.10 MPa of fluorine gas have been studied at 573–773 K. The original stage-1 structure of C2.5F with semi-ionic C–F bonds and planar sp2 carbon sheets is maintained in most part of the compound after the reaction at 573 K, although a large number of covalent C–F bonds are formed on the surface. This compound is partially or completely converted to poly(carbon monofluoride), (CF)n, with covalent C–F bonds and puckered sp3 carbon sheets at 673 or 773 K, respectively. Single-phase (CF)n obtained at 773 K possesses remarkably small BET specific surface area, 61 m2/g carbon, almost unchanged from the value of the precursor C2.5F (69 m2/g carbon). In this reaction, the accommodation of fluorine atoms supplied from the atmosphere into the galleries of C2.5F is facilitated by the rearrangement of originally intercalated fluorine atoms in the GIC, forming (CF)n with fewer defects compared to those by the conventional direct fluorination of graphite. [Copyright &y& Elsevier]

Highly fluorinated C X F samples (1