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In order to prepare self-standing and flexible slow neutron reflectors made of graphite fluoride (GF) with high contents of (C2F)n structural phase, graphite foils of different thicknesses were used as starting materials for gas (F2)/solid fluorination. The maximal interlayer distance of GF was obtained with this phase thanks to the stacking sequence FCCF/FCCF; this is mandatory for the efficient reflection of slow neutrons. 71 and 77% of the (C2F)n phase were achieved for graphite foils with thicknesses of 1.0 and 0.1 mm, respectively. The interlayer distances were 8.6 Å as expected. The fluorination conditions (static mode, a long duration of 24 h, annealing in pure F2 gas for 24 h, and temperatures in the 390–460 °C range) were adapted to large pieces of graphite foils (7 × 7 cm2) in order to both avoid exfoliation and achieve a homogeneous dispersion of fluorine atoms. This process was also efficient for thinner (0.01 mm thick) graphitized graphene oxide foil. 56% of the (C2F)n phase and an interlayer of 8.6 Å were achieved for this foil when fluorination was performed at 430 °C. Whatever the nature and the thickness of the foil, their flexibilities are maintained. [ABSTRACT FROM AUTHOR]

To elucidate how different spatial oxygen-containing groups influenced lithium-storage performance of graphene matrix, and further establish a clear structure-performance relationship, graphene framework was strategically functionalized with carboxylate and sulfonate groups and oxygen-free aniline ones as a reference. Due to maximum lithiation effect, spatially sulfonate functionalized graphene delivered the best electrochemical performances in lithium-ion batteries. [Display omitted] Graphene derivative materials are widely used as anode component in lithium-ion batteries. However, there is still a lack of reliable and foresighted guides helpful for designing high-performance graphene-based electrode materials. To this end, we strategically chose challenging graphite fluoride as starting material for the derivatization of graphene in order to exclude interference factors. As a result, graphene framework was functionalized with oxygen-containing carboxylate and sulfonate groups and oxygen-free aniline units at a similar functionalization degree. Due to the strong effect of lithiation, out-of-plane p -aminobenzoic acid blocks boosted the lithium-storage capacity of graphene matrix to 636 mAh g−1 at 0.1 A/g, and sulfanilic acid blocks maximized this value to 873 mAh g−1. Sadly, oxygen-free aniline functionalized graphene material only delivered a specific capacity of 88 mAh g−1. Meanwhile, spatial lithiated carboxylate and sulfonate units endowed graphene framework with better rate capability and cycling stability. Such a structure-performance relationship established herein was beneficial for the design and preparation of high-performance graphene derivative electrode materials. [ABSTRACT FROM AUTHOR]

Discovery of new electrochemical redox motifs is essential to expand the design landscape for energy-dense batteries. We report a family of fluorinated reactants based on pentafluorosulfanyl arenes (R-Ph-SF5) that allow for high electron-transfer numbers (up to 8-e−/reactant) by exploiting multiple coupled redox processes, including extensive S–F bond breaking, yielding capacities of 861 mAh·greactant−1 and voltages up to ∼2.9 V when used as catholytes in primary Li cells. At a cell level, gravimetric energies of 1,085 Wh·kg−1 are attained at 5 W·kg−1 and moderate temperatures of 50 °C, with 853 Wh·kg−1 delivered at >100 W·kg −1, exceeding all leading primary batteries based on electrode + electrolyte (substack) mass. Voltage compatibility of R-Ph-SF5 reactants and carbon monofluoride (CFx) conversion cathodes further enabled investigation of a hybrid battery containing both fluorinated catholyte and cathode. The hybrid cells reach extraordinarily high cell active mass loading (∼80%) and energy (1,195 Wh·kg−1), allowing for significant boosting of substack gravimetric energy of Li−CFx cells by at least 20% while exhibiting good shelf life and safety characteristics. [ABSTRACT FROM AUTHOR]

Graphites covalently intercalated with fluorine to form (C 2 F) n structural type compounds shows a dramatic increase of the interlayer distance up to by a factor of almost 3 to reach ∼9 Å. Such graphite fluoride compounds containing only carbon and fluorine offer the rare opportunity to bridge the so-called gap in the reflectivity of neutron reflectors. Slow neutron reflectors are of great interest in designing neutron sources as well as in fundamental and applied science; they require synthesizing high thermal and chemical compound stability graphite fluorides. In this work, a new strategy is proposed for synthesizing (C 2 F) n compounds in a well-controlled method. Our results show that the outcome (C 2 F) n has a covalent character with only sp3 hybridized carbon atoms. Moreover, C–F bonds in the fluorocarbon sheets and CF 2 groups on the sheet edges lead to the desired stability and hydrophobic character. A dedicated home-made neutron diffractometer was built for measurements of double-differential neutron cross sections of crystals with specific large interlayer distances found in (C 2 F) n compounds. We demonstrate that the synthesized fluorine intercalated graphites developed effectively cover the gap in the reflectivity for the new generation of neutron reflectors. [Display omitted] [ABSTRACT FROM AUTHOR]

The high energy density of fluorinated graphite (CF x) based lithium primary battery has aroused tremendous attention. However, the nonconductive CF x always induces high interface impedance and low power density. Herein, the carbon conductive network is generated by thermal treatment of resorcinol/formaldehyde (RF) resin on CF x and RF resin spheres (RF RSs), a conductive carbon layer coats on CF x surface, the electrical conductivity of CF x is improved. The oxygen functional groups in incomplete carbonized RF RSs also dedicate to the electrochemical performance of CF x. When different mass ratios of CF x /RF RSs are employed, the cathodes exhibit improved rate performance and voltage plateaus, and the initial voltage delays observed in CF x are significantly reduced. Notably, CF x /RF RSs−13 cathode delivers an impressive discharge capacity of 843.8 mAh g−1 with a voltage plateau of 2.68 V at 10 mA g−1. This leads to the maximum energy density of 2174.9 Wh kg−1 and a peak power density of 18600 W kg−1. Additionally, CF x /RF RSs−13 cathode demonstrates commendable electrochemical stability across a wide temperature spectrum (−20–70 °C). Given these superior electrochemical attributes, the CF x /RF RSs combination holds significant promise for deployment in high-power devices and for standard operations under extreme temperature conditions. • Carbon conductive network is induced by heat treatment of RF resin on CF x and RF RSs. • Oxygen functional groups in RF RSs also make for electrochemical performance of CF x. • CF x /RF RSs−13 gives peak energy and power densities of 2174.9 Wh kg−1, 18600 W kg−1. • CF x /RF RSs−13 demonstrates commendable electrochemical stability from −20 to 70 °C. [ABSTRACT FROM AUTHOR]

• An in-depth comparative study of three different aluminum-fluorides. • Fluorides can significantly raise the ignition and combustion performance of Al. • The promoting effect on aluminum combustion can be ranked: FG > PTFE > MgF 2. • The Al2O3 shell underwent pre-ignition reaction with fluorides. To improve the combustion characteristics of micron-sized aluminum (Al) powder, a composite powder was prepared by doping a small amount (15 wt%) of magnesium fluoride (MgF 2), polytetrafluoroethylene (PTFE), and fluorinated graphite (FG) into the aluminum powder through solution dispersion method. The physical phase composition, micro morphology, thermal reactivity, and combustion performance of the composite powders were also characterized. The findings suggest that the promoting effect of the three fluorides on aluminum combustion can be ranked in the following descending order: FG > PTFE > MgF 2. The fluorides can to erode the Al 2 O 3 shell layer directly, thus creating cracks and reaction pathways for the Al core enclosed within the shell. Moreover, the gasification of AlF 3 within the combustion products can escape from the surface of Al particles and promote the oxidation combustion of the exposed aluminum, which enhances the diffusion reaction on the active aluminum surface. [Display omitted] [ABSTRACT FROM AUTHOR]

The damping properties of fluorinated polyacrylate (FPA) composites with expanded graphite (EG) partially substituted for mica as fillers have been studied. EG was prepared by a rapid expansion method by microwave (MW) irradiation. The effects of the EG and natural graphite (NG) as partial substitutions for mica and the blending of epoxy (EP) resin with the polyacrylate emulsion on the damping performance of the composites was investigated with dynamic mechanical analysis (DMA). The results showed that adding EG as a partial substitute for the mica improved the intensity of the loss peak of the DMA tanδ and broadened the corresponding high loss factor (tanδ > 0.3) temperature range of the PA/EP composites. In comparison with NG or the mica, EG was more efficient in improving the damping properties of the composites. When the weight content of EP was 4% and EG was 6%, tanδ reached the maximum value of 2.16, and the corresponding temperature range with tanδ > 0.3 was about 80 °C. [ABSTRACT FROM AUTHOR]

Fluorinated graphene-like materials are currently attracting much attention due to the tuning of their properties by changing the fluorine content and pattern on the graphene lattice. In this work, we report the redshift of absorption bands and the suppression (increase) of green (yellow-orange) photoluminescence (PL) in the spectra of transparent CF x crystallites as x decreases from ∼0.44 to ∼0.33. Time-dependent density functional theory (TDDFT) calculations reveal that the aromatic regions and polyene chains in the CF x layers are mainly responsible for the optical absorption of the samples in the ultraviolet and visible regions, respectively. The electron-hole recombination within branched aromatic rings or long carbon chains produces orange-red emission, while green-yellow PL is due to transitions of excited polyene electrons to half-occupied levels of aromatic carbon. Our results show that the optical properties of partially fluorinated graphite layers are determined by the size and shape of the remaining sp2 carbon regions, which can be varied by changing the fluorination conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

A new solid-state 19 F magic-angle spinning NMR signal at an isotropic 19 F chemical shift of −53 ppm is measured from graphite fluoride synthesized by reaction of graphite with F 2 at temperatures above 750 K with no catalyst. Two-dimensional NMR suggests the −53 ppm 19 F NMR signal originates from covalent fluoromethanetriyl groups belonging to ordered (C y F) n bulk domains composited with the major (CF) n domains. Quantitative 19 F and 13 C NMR find y = 4.32 ± 0.64 . DFT calculations of NMR chemical shifts for unsaturated fluorographene models show that a (C 4 F) n phase with fluorine bound covalently to a single side of the carbon layer best explains the observed NMR chemical shifts. We assign the new phase to this (C 4 F) n structure, which constitutes up to 15% of the carbon in our graphite fluoride composites. The (C 4 F) n content of the composite affects bulk electrochemical properties in a manner similar to graphite fluorides produced by conventional, catalyzed fluorination processes. [ABSTRACT FROM AUTHOR]

A graphite-mediated microwave-based strategy was used for solid-state exfoliation of graphite fluoride in a few seconds, followed by a simple yet efficient separation to obtain exfoliated materials based on the density difference between graphite and graphene fluoride in solvent. The microwave-exfoliated graphene fluoride was a few layers thick and electrically conductive. The electrochemical testing of pouch-cell supercapacitors assembled by using the exfoliated graphene fluoride electrodes and a novel microemulsion-based electrolyte showed reasonable performance with typical electrical double-layer capacitance behavior and good rate capability (gravimetric specific capacitance: 3.2 F g−1 at 500 mA g−1 and 3.1 F g−1 at 5000 mA g−1). The BET specific surface areas of the as-exfoliated graphene fluoride are ~60–80 m2 g−1, which could be increased by activation using this simple yet versatile microwave-based method for further improvements on the electrochemical performance. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen reduction reaction (eNRR) is a sustainable alternative to the traditional Haber–Bosch process due to its eco‐friendly nature and capability of utilizing renewable energy. However, its low Faradic efficiency (FE), caused by the excessive adsorption and reduction of protons, has been regarded as the main challenge, which leads to low ammonia yield as well. Herein, a carbon‐supported iron electrocatalyst is reported, which is fabricated by low‐temperature (300 °C) potassium vapor reduction of FeF3‐intercalated graphite fluoride, for efficient electrochemical nitrogen reduction. The strategy enables the unique formation of exposed Fe nanoparticles uniformly anchored on graphene and in situ doped with fluorine heteroatoms. These specific features can alter the electronic configuration of the Fe nanoparticles, leading to strong surface polarization that boosts nitrogen absorption capability for eNRR, resulting in high FE (41.6%) and ammonia yield rate (53.3 μg h‐1 mg‐1) simultaneously. First‐principle calculation attributes this enhanced eNRR capability to more empty orbitals carried by the Fe atoms through the electron transfer with F dopant and substrate. As a versatile strategy for synthesizing various ultrafine and highly dispersed metal nanoparticles on the carbon support, this work might shed light on rational designing essential electrocatalysts with effective electronic structure manipulation. [ABSTRACT FROM AUTHOR]

We present a Hybrid Multiphase Porous Electrode Theory (Hybrid-MPET) model that accurately predicts the performance of Medtronic's implantable medical device battery lithium/carbon monofluoride (C F x) - silver vanadium oxide (SVO) under both low-rate background monitoring and high-rate pulsing currents. The distinct properties of multiple active materials are reflected by parameterizing their thermodynamics, kinetics, and mass transport properties separately. Diffusion limitations of Li + in SVO are used to explain cell voltage transient behavior during pulse and post-pulse relaxation. We also introduce change in cathode electronic conductivity, Li metal anode surface morphology, and film resistance buildup to capture evolution of cell internal resistance throughout multi-year electrical tests. We share our insights on how the Li + redistribution process between active materials can restore pulse capability of the hybrid electrode, allow C F x to indirectly contribute to capacity release during pulsing, and affect the operation protocols and design principles of batteries with other hybrid electrodes. We also discuss additional complexities in porous electrode model parameterization and electrochemical characterization techniques due to parallel reactions and solid diffusion pathways across active materials. We hope our models can complement future experimental research and accelerate development of multi-active material electrodes with targeted performance. • Hybrid-MPET model of Medtronic's high-rate Li/CF x -SVO battery is presented. • Separate material properties, diffusion limitation, and aging are accounted for. • Model prediction accuracy is validated on large battery dataset. • Cell pulse capability restoration is explained by Li＋ redistribution across materials. • Li＋ redistribution impact on general cell operation and design principles are discussed. [ABSTRACT FROM AUTHOR]

Medtronic Implantable Cardioverter Defibrillators (ICDs) and Cardiac Resynchronization Therapy Defibrillators (CRT-Ds) rely on high-energy density, lithium batteries, which are manufactured with a special lithium/carbon monofluoride (C F x)–silver vanadium oxide (SVO) hybrid cathode design. Consistently high battery performance is crucial for this application, since poor performance may result in ineffective patient treatment, whereas early replacement may involve surgery and increase in maintenance costs. To evaluate performance, batteries are tested, both at the time of production and post-production, through periodic sampling carried out over multiple years. This considerable amount of experimental data is exploited for the first time in this work to develop a data-driven, machine learning approach, relying on Generalized Additive Models (GAMs) to predict battery performance, based on production data. GAMs combine prediction accuracy, which enables evaluation of battery performance immediately after production, with model interpretability, which provides clues on how to further improve battery design and production. Model interpretation allows to identify key features from the battery production data that offer physical insights to support future battery development, and foster the development of physics-based model for hybrid cathode batteries. The proposed approach is validated on 21 different datasets, targeting several performance-related features, and delivers consistently high prediction accuracy on test data. • ICD battery reliability is ensured with life-test experiments spanning multiple years. • ML provides accurate prediction of life-test experiments based on production data. • Interpretable ML fosters the development of battery design and physics-based models. • Approach is validated on 21 datasets, analysed for the first time in the literature. [ABSTRACT FROM AUTHOR]

High-concentration electrolytes (HCEs) are favored in graphite cathode-based dual-ion batteries (DIBs) due to their high oxidative stability and good interphase compatibility with both anode and cathode. Although a localized high-concentration electrolyte (LHCE) with the similar solvation structure as HCE is proposed for graphite cathode by adding weakly solvated fluorinated cosolvents, the balance between salt concentration and fluorinated cosolvent has not been investigated. Herein, various electrolytes were prepared by introducing tris(2,2,2-trifluoroethyl) phosphate (FTEP) into the HCE composed of potassium bis(fluorosulfonyl)imide (KFSI) and triethyl phosphate (TEP), and the moderate concentrated electrolyte at the TEP/FTEP volume ratio of 5:1 can stabilize K/graphite DIBs with the capacity of 45 mAh g−1 after 300 cycles at 0.5 A g−1. The abundant ion–solvent complexes as HCE and the entrance of FTEP contribute to building stable FSI−-derived cathode/electrolyte interphase with the KF-rich inner layer. Importantly, FTEP replaces partial TEP solvents to coordinate with FSI−, enhancing the electrolyte oxidative stability, whereas their weak interaction further suppresses the solvent co-intercalation. As a proof, this electrolyte enables high output voltage (3.75 V) and good cyclability of dual-ion full cells coupled with tellurium anode. This work will promote the development of fluorinated cosolvent-modified LHCEs for high-performance DIBs. The balance between salt concentration and fluorinated cosolvent is discovered for graphite cathode with high-rate capacity and good cyclability. Abundant ion–solvent complexes and the participation of fluorinated cosolvent facilitate building anion-derived cathode/electrolyte interphase. The coordination of fluorinated cosolvent with anions to replace some solvent molecules enhances the electrolyte oxidative stability, whereas the weak interaction further suppresses the solvent co-intercalation. [Display omitted] • Graphite cathode exhibits high-rate capacity by introducing FTEP as fluorinated cosolvent in HCE. • Abundant ion–solvent complexes and FTEP's participation help build anion-derived and F-rich CEI. • Weak interaction between FTEP and anion suppresses solvent co-intercalation into graphite cathode. [ABSTRACT FROM AUTHOR]

Rechargeable batteries based on graphite are considered as promising alternatives for energy storage applications. The charge/discharge mechanisms of these batteries results from the intercalation and de-intercalation driven electrochemically by the atoms or molecules of the electrodes in contact with a liquid electrolyte. These solutions are often complex systems engineered to stabilize and allow the transport of the evolving moieties. In this article, we isolate the effect on the graphite structure of a chemical component of novel electrolytes, the aluminum fluoride (AlF 3), by dosing this pure compound in the gas phase over high oriented pyrolitic graphite (HOPG) substrates at 10−9 mbar and 300 K. We performed an extensive experimental study involving surface characterization and beam analysis techniques, and developed a model of the sorption substantiated in ab-initio calculations. We found a preferential interlaminar absorption when dosing in the direction transversal to the carbon planes. The intercalation in the HOPG is spontaneous and non-reactive, and increases the interplanar spacing by 20%. A charge transfer of 0.65 e− per formula from graphite to AlF 3 is calculated for the intercalate. Since the absorption depends on the roughness of the substrate we may infer that the intercalation proceeds through the step-edges. These features may contribute to the development of novel quasi-2D devices for special applications. [Display omitted] ● We isolate the effects of the AlF 3 over the crystalline structure and chemistry of HOPG by studying the system AlF 3 /HOPG in UHV by STM, XPS, RBS, and using DFT calculations to build an absorption model. ● The AlF 3 aggregates diffuse into the substrate, separating the carbon layers locally, and in turn generate changes in the density of electronic states of neighboring regions. ● The AlF 3 and HOPG retain their chemical identity ruling out the formation of metallic Al formation on the surface and any type of covalent bond between C and AlF 3 ● Surface defects and rsubstrate roughness are parameters that control the thickness of the fluoride intercalates. ● The calculated intercalation energy favours this process over adsorption, predicting a value of 4.41 V for its deintercalation potential. [ABSTRACT FROM AUTHOR]

In a typical Al–air battery, the air cathode functions as a deposition substrate for discharge products while allowing O2 entrance. Herein, we present an air electrode that simultaneously allows two discharge processes. The function of the metal–air battery is enabled by using porous carbon nanotube (CNT)-based tissue substrates. In contrast, the fluorinated graphite (CFx) coating on the CNT substrate provides an additional discharge process, enhancing discharge capacity. Two CFx loadings are investigated, and their performances are compared with that of a pristine CNT tissue. Electrochemical evaluations, including half- and full-cell measurements, are performed to examine the effect of the coating layer thickness on the ability of the cell to function at high discharge rates. High CFx loadings improved the cell performance and increased discharge capacities (an increase of ~ 3 mAh cm−2 for the 0.1 mA cm−2 and ~ 5 mAh cm−2 for the 0.25 mA cm−2 evaluations) until reaching high discharge loads. When applying 0.5 mA cm−2, the additional layer restricts O2 access into the cell, preventing the metal–air battery from functioning as intended. High-resolution scanning electron microscopy and energy-dispersive X-ray spectroscopy are used to characterize the discharge products deposited on this unique electrode. [ABSTRACT FROM AUTHOR]

[Display omitted] Low energy density is the major obstacle for the practical all-solid-state supercapacitors, which may be raised by the combination of the pseudocapacitance with the electrochemical double-layer capacitance. Although graphene and polyaniline have been demonstrated two effective materials, the synthetic route of graphene and their hybrid mode largely dictated the capacitive performances and cyclability of graphene/polyaniline nanocomposites. Herein , we employed commercial graphite fluoride as the precursor to obtain graphene with a well-preserved carbon lattice. After graphite fluoride functionalization by p -phenylenediamine (p PDA) and in situ oxidative polymerization of anilines, polyaniline (PANI) chains were covalently attached to graphene framework through p PDA bridges. Multiple characterizations were performed to confirm the covalent binding mode between graphene scaffolds and PANI partners, and electrochemical tests unraveled the as-prepared G– p PDA–PANI triads delivered a gravimetric capacitance as high as 638F g−1 and a further amplified volumetric capacitance (up to 759F cm−3). The bendable all-solid-state supercapacitors yielded an encouraging energy density of over 18 W h L−1 at a power density high to 5,950 W L−1, while exhibiting an exceptional rate capability, cycling stability and mechanical flexibility. [ABSTRACT FROM AUTHOR]

A new proposal for the electronic structure of carbon monoxide CO is presented. The approach involves the creation of an additional half-filled 2p orbital in the oxygen atom by the transfer of an electron from the filled 2p orbital to one of two half-filled hybridized 2spz orbitals in the carbon atom. The result is a triple bond comprising one sigma bond and two pi bonds between C and O strengthened by an ionic bond contribution. The proposed structure accounts for many unusual features of the molecule CO including the observed direction of the dipole moment, which is considered anomalous based on the concept of electronegativity of the constituent atoms as well as the increased bond dissociation energy compared with isoelectronic nitrogen N2. It also provides a basis for the CO molecule being a stable ligand combining with transition metals using the lone electron pair in the filled 2spz orbital of the carbon atom. The electron transfer mechanism is effectively applied to the isoelectronic compound boron monofluoride BF and predicts properties of the undetected isoelectronic molecule BeNe. Finally, the method proposes new electronic structures for the cyanide ion CN which resolves the long-standing puzzle of "charge reversal" on the molecule and the carbon monofluoride ion CF+. [ABSTRACT FROM AUTHOR]

Fluorinated single-layer diamond ("F-diamond") is a new form of two-dimensional (2D) carbon allotrope. Herein, poly(dicarbon monofluoride) (C 2 F) n which is essentially made of stacked layers of "F-diamane" has been synthesized and exfoliated in a variety of solvents to yield well-dispersed ultrathin sheets. Microscopic and spectroscopic analyses revealed that the exfoliated nanosheets retained the "F-diamane"-like structure. The experimental results are also supported by density functional theory (DFT) calculations. Image 1 • Poly(dicarbon monofluoride) (C 2 F) n was synthesized by the fluorination of graphite. • The (C 2 F) n is essentially made of stacked layers of "F-diamane". • Liquid-phase exfoliation of (C 2 F) n yielded ultrathin nanosheets. • The "F-diamane"-like structure was retained after exfoliation. • Density functional theory calculations support the experimental results. [ABSTRACT FROM AUTHOR]

Although the primary lithium/fluorinated graphite battery has a high energy density of 3725 Wh kg−1, its complete irreversibility based on a conversion reaction between Li and fluorinated graphite hampers wide applications in rechargeable systems. Here, a new rechargeable three‐electrode battery configuration involving lithium, fluorinated graphite, and sulfur electrodes is developed, in which the initial middle‐fluorinated graphite cathode can be electrochemically transformed into a hybrid lithium anode, showing a low overpotential (12 mV), long cycle life (2000 h) and good deep stripping/plating features. This rechargeable battery delivers a high gravimetric energy density of 507.7 Wh kg−1 on the basis of the total mass of the three‐electrode materials. Moreover, the excessive consumption of lithium in the system can be in situ replenished, further lengthening the lifespan. [ABSTRACT FROM AUTHOR]

• Al/B/CF microspheres have been prepared through self-assembly in emulsion. • Spherical Al/B/CF fuel exhibits high energy density and superior reactivity. • The combustion reaction of single Al/B/CF microsphere are studied for the first time. • The CF content and Al/B mass ratio have significant effects on combustion behaviors. Aluminum (Al) is one of the most widely used metal fuels in the fields of automotive airbags, solid propellants, explosives and pyrotechnics. Unfortunately, it is hard to meet further demand of practical applications owing to the comparatively low calorific value. Herein, graphite fluoride (CF) and boron (B) are employed to construct Al/B/CF microspheres through self-assembly in emulsion to obtain high energy density and significantly improved combustion performance resulted from synergistic reaction between Al and B reacted with fluorine. The Al/B/CF microspheres with pore structure have uniformly distribution of components and the average size range from 60 to 600 μm. Based on the experimental results, CF content and Al/B mass ratio have significant important effects on the combustion behavior and pressure output. The highest burning rate (301.74 m/s) and pressurization rate (77.78 MPa/s) are obtained for the Al/B/CF microspheres with CF content of 50 wt% and Al/B mass ratio of 3 to 1, respectively. Furthermore, the combustion reaction process of single Al/B/CF microsphere are studied for the first time to understand the synergistic reaction between high reactivity of Al and high energy of B reacted with fluorine. This work demonstrates that introducing CF and B to construct Al/B/CF microspheres is an efficient strategy to achieve high energy density and reactivity for the practical applications. [ABSTRACT FROM AUTHOR]

A study of the processes of the thermal carbonization of silicon monoxide in the presence of nonstoichiometric carbon monofluoride demonstrated that raising the annealing temperature of mixtures of SiO and CFx powders in a quasi-closed volume to 1000°C and higher leads to the formation of whisker-like SiC nanocrystals. It is found that, in parallel with the known crystallization of SiC nanowires as a result of the interaction of SiO vapor with carbon monoxide, the previously undescribed interaction of CO with gas-phase silicon difluoride SiF2 takes part in their formation. At temperatures below 1200°C, this reaction is dominant and makes the most pronounced contribution to the yield of SiC nanowires. [ABSTRACT FROM AUTHOR]

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]

Microwave (MW) irradiation is often used in preparation of nanomaterials. Here, we investigate MW exfoliation patterns of intercalated fluorinated graphite (C2F) depending on the nature of the "guest". The resulting highly exfoliated graphites (multi-layer graphenes) show advantageous characteristics, as compared to the products of convective heating. [ABSTRACT FROM AUTHOR]

With the development of portable and flexible electronic devices, demends for high-performance thermal management materials with high thermal conductivity and electrical insulation are growing. Recently, graphene fluoride has received numerous attention from science community due to its high thermal conductivity and electrical insulation. Here, we report an advanced exfoliated graphene fluoride (EGF) film as a high performance heat spreader and thermal interface material for flexible electronic devices, which simultaneously exhibits ultrahigh thermal conductivity, excellent electrical insulation, and satisfactory flexibility. Commercially available graphite fluoride was directly exfoliated into graphene fluoride solution using ball milling method, followed by preparing ultrathin graphene fluoride films to take full advantage of graphene fluoride properties for heat dissipating applications. The resultant films show a tunable thermal conductivity by altering the thickness of films and show a superior in-plane thermal conductivity of 242 W m−1 K−1 and exceptional through-plane thermal conductivity of 21.8 W m−1 K−1 at the thickness of 10 μm. More interestingly, the graphene fluoride films possess excellent flexibility. The newly developed EGF film provides a creative opportunity for fabrication of multifunctional highly flexible materials, which may promote the development of heat dissipation materials in next generation flexible electronics. Image 1 [ABSTRACT FROM AUTHOR]

Graphite is the most suitable material as dry lubricant. However, its application as a lubricant is limited with necessity of moisture vapors. Alternatively, polytetrafluoroethylene (PTFE) has an excellent lubrication property but does not have mechanical characteristics. The effect of gamma radiation doses on the lubrication behavior of graphite –PTFE (Inoflon A-408) system has been studied using (TR-TW-30L) tribotester with thrust washer attachment. Different compositions of graphite and PTFE were prepared and irradiated by gamma rays. Improved tribological properties of graphite –PTFE system showed by decrease in coefficient of friction and wear. SEM-EDX, XRD and contact angle analysis confirm fluorination of graphite by gamma radiation exposure leading to the development of novel dry lubrication system. [ABSTRACT FROM AUTHOR]

• Chemically inert graphite fluoride (GiF) could be modified by concentrated sodium hydroxide aqueous solution. • Structure and compositions of modified GiF (MGiF) could be delicately regulated. • Oxygen-containing groups were introduced in MGiF. • MGiF was much easier exfoliation than unmodified GiF. Saturated or nearly saturated graphite fluoride (GiF) is difficult to be modified for their chemically inert properties. Dramatic performing conditions usually were required, and it's not facile to tune the fluorine content and to introduce reactive groups for the reported methods. In the present paper, a simple and operable method has been reported for modified GiF (MGiF) decorated with different contents of fluorine and functional oxygen groups. GiF was treated with 12˜25 M sodium hydroxide (NaOH) solution at 60°C. Besides C F and C C covalent bonds, C and O in the forms of carbonyl and hydroxyl bonds have been observed in the structure of modified GiFs. Their contents of carbonyl and hydroxyl groups and the crystalline structure of the modified GiF could be feasibly regulated by changing the concentrations of NaOH aqueous solution. MGiFs can exfoliate more easily than GiF due to the existence of the functional oxygen groups, and the exfoliated products of graphene oxyfluoride with 1˜3 layers have higher dispersion stability in N-methyl-2-pyrrolidone. [ABSTRACT FROM AUTHOR]

Experiments with a Langmuir probe and optical emission spectroscopy combined with actinometry were carried out in inductive CF4/O2 discharges at three pressures of 8, 15, and 25 mTorr. The measured electron energy probability functions are approximately Maxwellian at any oxygen content. The measured electron density decreases with increasing the oxygen in the oxygen content below 20%, beyond which it remains nearly constant. On the other hand, the measured electron temperature is not sensitive to the content. The atomic fluorine density estimated by actinometry increases markedly as oxygen is mixed to CF4 discharges, and then reaches the maximum around the oxygen content of 20%–30%, beyond which it decreases with increasing oxygen content. The atomic oxygen density increases with the increase in the oxygen content except for the oxygen content higher than 90%. A global model for electronegative plasma is used in order to investigate the plasma chemistry in CF4/O2 discharges assuming the Maxwellian electron energy distribution. The model results are compared with the experimental results, obtaining reasonably good agreement. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen doped sub-fluorinated graphite with larger layer spacing material. • Simple and effective modified method without high temperature or pressure. • Fluorinated graphite can obtain a power density of 40.23 kW kg−1. • The dependence of cathode material structure, LiF and cathode swelling is provided. Lithium/carbon fluorides batteries own a high theoretical energy density of 2180 Wh kg−1 and exceptional shelf life, but poor electrode kinetics, low electronic conductivity of cathode, and cathode swelling during discharge. In this work, fluorinated graphite is modified by a controllable solvent treatment using N-methyl-2-pyrrolidone at medium temperature (50 ∼ 90 °C). The modified fluorinated graphite is doped with nitrogen atoms and owns increased interlayer spacing and electrochemical active semi-ionic C F bonds, providing a higher conductivity and facilitating the diffusion of Li+ or solvent Li+. The maximum power density of the modified fluorinated graphite is 40.23 kW kg−1 at 25C. To elucidate the cathode swelling of the fluorinated graphite, in-situ confocal optical microscope and in-situ X-ray diffraction are conducted for the first time. It is found that the formation and accumulation of crystalline LiF during discharge, as well as the interlayer spacing of fluorinated graphite, are related to the cathode swelling in liquid electrolyte. [ABSTRACT FROM AUTHOR]

Aqueous zinc ion batteries (AZIBs) are considered as a promising candidate for large-scale energy storage due to its superior energy density, high specific energy, environmental friendliness and low cost. However, the dendrite growth and side reaction of zinc anode severely hinder its stability and availability. Herein, commercial glass fiber separators are modified by graphite fluoride nanoflakes via vacuum filtration (denoted as GFNs-PVDF@GF) to reinforce Zn metal anode. The GFNs-PVDF@GF separator acts as an efficient ions transport modulator to homogenize Zn2+ transport and suppress SO 4 2− flux due to strong zinc affinity and electronegativity of GFNs, thereby restraining the growth of zinc dendrite and the formation of byproducts. Accordingly, the Zn||Zn symmetric cell harvests a stable and reversible cycling for 1800 h at 1 mA cm−2 and operates at 5 mA cm−2 for over 900 h. The assembled Zn||MnO 2 full cells deliver a capacity retention of 92% after 200 cycles at 1 A g−1. Our results provide a simple and effective strategy of improving stability of zinc anode for high-performance AZIBs. • Separator modification by graphite fluoride nanoflakes (GFNs) is demonstrated. • Strong zinc affinity of GFNs acts as an efficient ions transport modulator. • Zinc dendrite and byproducts are suppressed with improving Zn anode stability. • Symmetric and full cells with GFNs-modified separator exhibit improved performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorinated graphite (FG) CF 0.4 is irradiated with a synchrotron white beam. • XPS spectra showed little change in the composition of the irradiated layers. • Under photon action, HNO 3 , NO 2 , NO, and N 2 decompose inside the FG matrix. • Embedded NO x molecules stimulate FG defluorination and vacancy formation. • Nitrogen from NO x molecules saturates the boundaries of vacancies. Layered fluorinated graphite material can become an efficient nanoreactor for photochemical reactions. In this work, we compared the photochemical behavior of partially fluorinated graphite (FG) and FG containing nitrogen oxides in the interlayer space (NO x @FG) under the action of a high-intense polychromatic photon beam from the synchrotron radiation source BESSY II. Analysis of the chemical and electronic states of the samples was performed using X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. Density functional theory calculations were used to interpret and analyze the experimental data. It was found that nitrogen oxides promote the photo-induced degradation of the FG matrix, namely, its partial defluorination, formation of vacancies and doping with nitrogen, while the empty FG had a high photoresistance to synchrotron radiation. The results obtained can be used in the development of new approaches to the modification of graphene layers and in the creation of photostable materials for optical elements. [ABSTRACT FROM AUTHOR]

Reports on a theoretical study on electronic states of carbon monofluoride and on the predissociation of the lower lying states by multi reference single and double excitations configuration interaction (MRDCI) calculations. Ab initio MRDCI calculations on the doublet electronic states of carbon monofluoride; Potential energy curves.

A novel method to fabricate porous silicon–carbon nanocomposites has been suggested. The method uses carbon monofluoride reduction by silicon. The produced composite materials are formed by silicon nanoparticles confined into a carbon shell. The contacts of these particles provide current flowing across the formed carbon matrix. The dependences of density, porosity, and resistivity on the composition of Si–C composite pellets obtained by the suggested method have been determined. The studied materials are of interest for developing negative electrodes for lithium-ion batteries with high capacity. [ABSTRACT FROM AUTHOR]

In the present paper, graphite fluoride compounds C x F with various degrees of fluorination (x = 4, 2 and 1), i.e., with different C-F bonding characteristics, were systematically investigated using X-ray Raman Spectroscopy (XRS) and X-ray and neutron diffraction by means of Pair Distribution Function (PDF) analysis. For both techniques, ab-initio calculations allow the experimental results and structural/bonding assignments to be explained and/or confirmed. Presented here for the three stoichiometries are results for the carbon and fluorine first-neighbour distances, the evolution of the electronic band structure due to the change of the carbon hybridization upon fluorination, and also the nature of the final states for 1s core-electron excitations. Since fluorination is limited by the diffusion of fluorine in the carbon lattice, the process is less effective in the bulk, where a graphitic core remains. The cross-checked XRS, PDF data and Density Functional Theory (DFT) simulations appear also to be a powerful method to highlight the presence of a residual graphitic core, even at the highest fluorine content, in such semi-disordered and structurally complex compounds. Image 1 [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • High-quality fluorographene nanosheets are fabricated by microwave-assisted liquid phase exfoliation. • The as-prepared fluorographene nanosheets are comprised of no more than four monolayers. • No other side reaction and impurity elements are introduced during the exfoliation process. • Fluorographene nanosheets exhibit excellent thermal stability and remarkable lubrication behavior in oil. Abstract Fluorographene (FG), as an important class of graphene derivatives, has shown great promise in high-performance devices and lubricating materials. However, the large-scale fabrication of high-quality and impurity-free FG nanosheets still remains a main challenge. Herein, a simple liquid-phase exfoliation approach to prepare thin FG nanosheets through the preliminary intercalation of raw graphite fluoride (GrF) particles by N,N-dimethyl formamide molecules, followed by a short-time microwave treatment is reported. Atom force microscopy measurements demonstrate that as-prepared FG nanosheets are comprised of no more than four monolayers after the microwave irradiation. After exfoliation, a small amount of aromatic C C groups in the FG nanosheets are restored, which slightly lowers the F content in FG as compared with the raw GrF. Besides, no other side reaction and impurity elements are introduced during the exfoliation process as revealed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The resultant high-quality FG nanosheets exhibit excellent thermal stability and remarkable lubrication behavior in oil, and thus can be used as a new class of graphene derivatives with the capability of large-scale fabrication for the future device and various other applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The naked-eye NH 3 sensor based on fluorinated graphene was obtained. • The effect of F atoms on the adsorption ability and charge transfer were identified. • The sensitivity of the NH 3 sensor can reach to 4.05% ppm−1. • The naked-eye NH 3 sensor needs no device fabrication, power supply or measuring equipment. Abstract Graphene has aroused continual and tremendous interest in gas sensing applications because of its unique properties. However, the graphene-based sensors still meet limitations such as inconvenient device fabrication, sustained power supply, specific measuring equipment, etc. Here, we find that fluorinated graphene (FG) shows an obvious color change (from white to dark yellow) in the presence of NH 3 which can be observed directly by the naked eye. PL measurement shows that the sensitivity of color change can reach a high value of ca. 4.05% ppm−1. The density functional theory calculations reveal that the F atoms on FG increase the adsorption ability and charge transfer of NH 3 molecules, resulting in the efficient color change. This work develops a naked-eye sensor which needs no device fabrication, power supply or measuring equipment, thus, can be potentially used to manufacture a cheap, sensitive and miniaturized NH 3 sensor. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A solvent-free urea melt synthesis to modify fluorinated graphene. • FGO functionalization to produce hydrophilic graphene with amino-groups. • Modified graphene sheets functionalized with good water-solubility. • Broaden the application in aqueous environments of fluorinated graphene. Abstract Fluorinated graphene has attracted a lot of scientific interest due to its excellent properties and novel structure, but its applications are still challenging because of its poor dispersion and severe agglomeration. We propose a solvent-free synthesis of novel modified fluorinated graphene oxide (mFGO) with good water compatibility with. We used graphene oxide (GO) prepared by Hummers method as a precursor. The oxygen-containing functional groups on GO were hydrothermally reacted to convert GO into FGO. Then, the amino functional groups were introduced to the FGO surface by a solvent-free urea modification reaction. This method produced graphene modified with both fluorine and amino groups in high yield. It shows great potential in introducing mFGO as a reactive modifier in waterborne epoxy materials for a variety of industrial applications. [ABSTRACT FROM AUTHOR]

Abstract Fluorine Graphite Intercalation Compounds are one of the most common cathode used in primary lithium batteries, mainly for their high delivering potential. Nevertheless, to increase their capacities, fluorine can be partially substituted by oxygen. Oxifluorides offer then versatility to design cathode materials delivering the upmost performances. Combining the choice of the precursor (either graphite oxide or sub-fluorinated graphite fluoride) and two-step synthesis processes, which include Hummers' oxidation and direct fluorination, allow the tuning of the fluorine and oxygen atoms distribution. According to the sequence, i.e. fluorination/oxidation or oxidation/fluorination, several oxifluorides were then prepared. On one hand, direct fluorination using F 2 gas resulted in homogeneous fluorine dispersion when precursor was graphite oxide. On the other hand, Hummers' oxidation was modulated according to the temperature parameter. C OH, C O C, COOH, CF, CF 2 and CF 3 were identified through multinuclear solid-state MAS-NMR. Covalence and environment, especially in-plane organization of those chemical groups, were assessed. When oxifluorides are then used as cathode in primary lithium battery, the better performances are obtained for 3 phases compounds where fluorinated part insured high potential whereas oxygenated part allowed durability to be reached; carbonaceous region providing conductivity. A maximum of about 2400 Wh/kg of energy density is attempted. Graphical abstract High performances of cathode materials for primary lithium battery have been obtained through bifunctionalization by fluorine and oxygen of graphite. Two steps synthesis: gas solid fluorination/Hummer's oxidation or oxidation/fluorination allow to get various functional groups and their repartition in graphite structure. Image 1 [ABSTRACT FROM AUTHOR]

Abstract Ice formation on surfaces is a fascinating phenomenon with a major impact on a huge range of human activities from airplanes and shipping to wind mill parks, power transmission and telecommunication. A significant amount of work has been dedicated to the development of icephobic surfaces, often with the basis in superhydrophobicity. However, most surfaces investigated so far have not been very robust (an issue for operation in harsh and high humidity environments). Anti-icing strategies for practical applications in harsh environments have therefore mainly been related to the development of heatable coatings and/or mechanical removal or, in the case of airplanes, de-icing with glycol. Here we present a robust and lightweight anti-icing coating based on fluorinated graphene. The new coating delays ice formation for a striking 90 min at −15 °C up to 6 h and 45 min at −5 °C. All experiments were carried out at high humidity (50–55%). We also present first experiments of anti-icing on pure graphene. The very superior performance of the fluorinated graphene can be explained as a favourable combination of very low surface energy and nanoscale roughness. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract In this paper, we investigate the adsorption of water monomer on fluorinated graphene using state-of-the-art first-principles methods within the framework of density functional theory (DFT). Four different types of methods are employed to describe the van der Waals (vdW) interactions between water molecule and the carbon surface: The traditional DFT calculations within the generalized gradient approximation (GGA), and three additional types of calculations using respectively the semi-empirical DFT-D2 method, the original van der Waals density functional (vdW-DF) method, and one of its variants. Two situations and totally four adsorption configurations are considered. Compared with the adsorption on pristine graphene, the adsorption energies of water on fluorinated graphene are significantly increased, and the orientations of water diploe moment are notably changed. The most stable configuration is found to stay right above the top site of the C atom which is bonded with F, and the dipole moment of water molecule aligns spontaneously along the surface normal. Highlights • The adsorption of water on fluorinated graphene is studied using state-of-the-art first-principles methods. • The water-carbon interactions are enhanced due to F decoration. • The dipole moment of water molecule aligns spontaneously along the surface normal. [ABSTRACT FROM AUTHOR]

Abstract Recently, Li-rich layered structure has been used in the cathode of lithium ion batteries because of its high specific capacity. However, this structure still has some problems including large irreversible capacity loss, significant deterioration of cycling performance and poor rate property. Therefore, in our study, graphite fluoride is used to modify the surface of Li 1.14 Ni 0.133 Co 0.133 Mn 0.544 O 2 through a facile solvent evaporating method. Due to conversion reaction of the graphite fluoride, the huge discharge capacity compensation during the first discharging can improve the coulombic efficiency significantly. As reaction products, the layer of LiF@carbon reduces the interfacial reactions and increases the reversible capacity. After modification by graphite fluoride, the discharge capacities are improved by 22% from 266 to 325 mAh g−1 at 0.1 C, and 13% at 2 C. After 100 cycles, the discharge capability at 1 C is increased by 13% from 180 to 203 mAh g−1. [ABSTRACT FROM AUTHOR]

Most water in the world is as saline water in seas and oceans. Desalination technology is a promising method to solve the global water crisis. Recently, many attentions have been paid to the graphene-based membranes in water desalination due to their low production cost and high efficiency. In this paper, molecular dynamics simulations are employed to investigate the effect of functionalized graphene nanosheet (GNS) membranes on the performance of salt separation from seawater in terms of water permeability and salt rejection. For this purpose, the hydrogenated (-H) and fluorinated (-F) pores were created on the GNS membrane. Then, the functionalized graphene membrane was placed in the middle of the simulation box in an aqueous ionic solution containing Na+ and Cl− ions. The applied pressure (in the range of 10-100 MPa) was used as the driving force for transport of water molecules across the reverse osmosis (RO) graphene-based membrane in order to obtain the water permeability and salt rejection. Also, radial distribution functions (RDFs) of ion-water and water-water as well as the water density map around the membrane were obtained. The results indicated that the hydrophilic chemical functions such as fluorine (-F) can improve the water permeability at low pressures. [ABSTRACT FROM AUTHOR]

Abstract This paper presents a novel method of structural optimization by using graphite particles ranging in size from 35 to 500 μm to fabricate conductive fluorinated ethylene–propylene composites for high-temperature bipolar plates. To investigate the effects of dispersion and packing density, the large graphite particles were decorated with fluorinated ethylene–propylene powders by ball milling, and the master batch of well-dispersed small graphite particles and polymer master batch was mixed with large graphite particles. The resulting fluorinated ethylene–propylene/graphite composite bipolar plates, which contained 65 wt% graphite, exhibited high electrical conductivity of 550 S cm−1. In particular, by modulating the electrical transportation paths between the large graphite particles with the well-dispersed fluorinated ethylene–propylene/graphite master batch, the orientation and dispersion of the graphite particles in the matrix resulted in enhanced electrical conductivity and mechanical properties. The preparation of structurally optimized fluorinated ethylene–propylene/graphite composite bipolar plates with well-dispersed graphite particles of different sizes provides a robust and scalable strategy for realizing high-performance and large-area bipolar plates. Graphical abstract Image 1 Highlights • FEP/graphite composites were prepared by melt-processing from a master batch. • Graphite particles of different sizes were dispersed in the master batch. • FEP/graphite composite bipolar plates (BPs) were prepared by compression molding. • Structurally optimized BPs had high electrical conductivity and mechanical properties. • The composites represent a robust and scalable strategy for large-area BPs. [ABSTRACT FROM AUTHOR]

After a review on the wide variety of inorganic fluorinated components in modern technologies, in particular for energy conversion/storage systems, the use of fluorinated carbons as electrodes for primary lithium batteries will be highlighted; in particular conventional graphite fluorides will be compared to recently investigated fluorinated carbon nanoparticles (F-CNPs) prepared from electrochemical reduction of molten carbonates. [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]

The detection of the carbon monofluoride cation CF+ was considered as a support of the theories of the fluorine chemistry in the interstellar medium. This molecule is formed by the reaction of HF with $${\rm C^+}$$. The rates of this reaction have been estimated previously by two different groups. However, these two estimations led to different results. The main goal of this work is to study the $${\rm HF + C^+}$$ reaction and determine new reactive rate coefficients. A large set of ab initio energies at the MRCI-F12/cc-pVQZ-F12 level was computed. The first reactive potential energy surface for the HF + C+ → CF+ + H reaction was developed using a reproducing kernel Hilbert space based method. The dynamics of the reaction was followed from quasi-classical trajectories. The results of such calculations showed that CF+ is produced in excited vibrational states. The rate coefficients for the $${\rm HF} + {\rm C^+} \rightarrow {\rm CF^+} + {\rm H}$$ reaction from 50 K to 2000 K are reported. The impact of these new data in the astrophysical models for the determination of the interstellar conditions is also explored. [ABSTRACT FROM AUTHOR]

Developing nanostructure hybrid electrode with multiple electroactive sites offer an encouraging path to build high-performance supercapacitors (SCs). Herein, we report fluorinated graphene (FG) -supported Nickel-Cobalt-Iron nitride nanoparticles on nickel foam (NCF-N@FG/NF), as a hybrid SCs electrode. They were fabricated via one-step nitrogenization treatment in NH 3 atmosphere at different temperatures 300–500 °C of the corresponding Ni-Co-Fe-tri-hydroxide/FG precursors. The optimal NCF-N@FG/NF hybrid, with Fe:Co:Ni 3:1:1(denoted as NCF-N@FG/NF-3/500 °C) yielded specific capacitance (capacity) of 2110 F/g (293.1 mAh/g) at 1 A/g, rate capability of 87.2% at 20 A/g, and capacitance retention of 97.6% after 5000 cycles. Asymmetric supercapacitor (ASC) device was set up using NCF-N@FG/NF-3/500 °C hybrid as the cathode and activated carbon supported NF (AC@NF) as the anode (denoted as NCF-N@FG/NF-3/500 °C/CKK membrane/AC@NF). The device exhibited a stable potential window of 1.5 V and excellent cycling stability with only 11.5% decrease of capacitance after 10 000 cycles. Also, it achieved an energy density of 56.3 Wh/kg at 0.5 A/g with a power density of 374.6 W/kg. The device retained an energy density of 39.5 Wh/kg at 10 A/g with a power density of 7484.2 W/kg. This work constitutes the first demonstration of using FG supported tri-metallic nitride nanoparticles as high energy Cathode, which could potentially enhance the energy storage performance of ASC devices. [ABSTRACT FROM AUTHOR]

The fluorination of two types of graphene oxides conducted by an easy and scalable deoxyfluorination reaction is reported. This reaction was carried out using diethylaminodifluorosulfinium tetrafluoroborate, a stable compound and an efficient reagent for replacing oxygenated functional groups of graphene oxide by fluoride. The graphene oxide produced by the Hummers’ method (GOH) showed lower reactivity than that produced by the Brodie’s method (GOB). X-ray photoelectron spectroscopy indicated that the highest fluorination degree achieved was 4.7 at.% when GOB was used, and the C F character corresponds to semi-ionic bonds. Additionally, a partial reduction of GO was concomitant with the functionalization reaction. The deoxyfluorination reaction changed the crystalline structure of GO, favoring the reconstruction of Csp 2 structure of the graphene lattice and reducing the number of stacked layers. The fluorination led to the modification of the electronic band structure of this material, increasing the band gap from 2.05 eV for GOB to 3.88 eV for fluorinated GOB, while for GOH the low flurionation led to a slight increase of the band gap, from 3.48 eV to 3.57 eV. [ABSTRACT FROM AUTHOR]

Epoxy composites with excellent toughness and strength have been successfully fabricated by direct incorporation of graphite fluoride (GrF) without using any solvent or surfactant modification. Owing to the strong interfacial interactions, the glass transition temperature of GrF/epoxy composites exhibits a significant improvement as observed by dynamic mechanical analysis. Mechanical characterizations on GrF/epoxy composites suggest that the optimal increase of tensile strength and Young's modulus is achieved at a low filler concentration of 0.5 wt%, which is attributed to the favorable level of the GrF dispersion in the epoxy matrix. A maximum toughening effect is obtained at the concentration of 1 wt% GrF in the epoxy matrix with a 1.5-fold improvement in fracture toughness. The generation of crack pinning and crack deflection in epoxy due to the existence of GrF platelets is proposed to be the main toughening mechanism. Besides, microcracks resulted from pulling out, layer breakage and interfacial debonding of GrF platelets also contribute to the improvement in the fracture toughness of GrF/epoxy composites. [ABSTRACT FROM AUTHOR]

Membrane distillation (MD) relies on superhydrophobic membranes that must achieve the competing goals of high liquid entry pressure (LEP) and high permeability. In this study, we developed the first superhydrophobic composite electrospun asymmetric membrane using fluorinated graphite (FG). We also provided among the first comparisons of the relative benefits of membrane asymmetry and composite coatings via 3D electrospinning and spraying. FG particles increased the roughness and reduced the zeta potential of the membranes. Superhydrophobic composite membranes had a contact angle of 157° (sliding angle of 7°) and an LEP of 327 kPa. Long-term MD testing revealed that FG particles could increase MD's sustainability while decreasing membrane wetting. Vacuum-assisted air gap membrane distillation (V-AGMD) showed that the composite asymmetric membrane outperformed the non-asymmetric version (composite nanofiber) membrane by 21 % in average water flux and 25 % in average thermal efficiency because of the asymmetric structure of the membrane. The numerical model developed for the V-AGMD system also successfully predicted the water flux generated experimentally from the composite nanofiber and composite asymmetric membranes. Our results confirmed that electrospun asymmetric FG membranes with high contact angle, low sliding angle, high permeability, and high gained output ratio (GOR) would be promising candidates for sustainable MD. [Display omitted] • The composite asymmetric membrane varied fiber size and coatings. • Fluorinated graphite coating shows superhydrophobicity and small sliding angle. • Surface charge of membrane reduced by fluorinated graphite • Electrospun asymmetric structure greatly improves the flux and thermal efficiency. [ABSTRACT FROM AUTHOR]