Fluoridation routes,function mechanism and application of fluorinated/fluorine-doped nanocarbon-based materials for various batteries:A review

With the popularity and widespread applications of electronics,higher demands are being placed on the performance of battery materials.Due to the large difference in electronegativity between fluorine and carbon atoms,doping fluorine atoms in nanocarbon-based materials is considered an effective way to improve the performance of used battery.However,there is still a blank in the systematic review of the mechanism and research progress of fluorine-doped nanostructured carbon materials in various batteries.In this review,the synthetic routes of fluorinated/fluorine-doped nanocarbon-based(CF_x)materials under different fluorine sources and the function mechanism of CF_x in various batteries are reviewed in detail.Subsequently,judging from the dependence between the structure and electrochemical performance of nanocarbon sources,the progress of CF_x based on different dimensions(0D–3D)for primary battery applications is reviewed and the balance between energy density and power density is critically discussed.In addition,the roles of CF_x materials in secondary batteries and their current applications in recent years are summarized in detail to illustrate the effect of introducing F atoms.Finally,we envisage the prospect of CF_x materials and offer some insights and recommendations to facilitate the further exploration of CF_x materials for various high-performance battery applications.

Improved Hemolytic Performance of Blood Pump with Fluorine-Doped Hydrogenated Amorphous Carbon Coating

Fluorine-doped hydrogenated amorphous carbon (a-C:H:F) film was deposited on a flow-straightener, impeller and diffuser surface (SUS 304) of an enclosed-impeller type flow blood pump using the ionization deposition method with a source gas of C6F5H. The surface characteristics of the a-C:H:F film were examined using atomic force microscopy, X-ray photoelectron spectroscopy, and measurements of surface roughness, friction and surface potential. The a-C:H:F film tends to increase surface roughness and the negative surface charge. In addition, the surface energy and friction decrease with fluorine dopant in the a-C:H film. To estimate the hemolytic performance of a blood pump with the a-C:H:F film coating, the amount of hemolysis was measured using a mock circulatory system (in vitro test) with 500 mL of pig blood containing sodium citrate. In vitro test was conducted for 180 min with the blood flow and pump head maintained at 5 L/min and 100 mmHg, respectively. The a-C:H:F film coating reduced the amount of hemolysis and improved the hemolytic performance. Decreasing the surface energy and negative surface charge of the a-C:H:F film contributes to the improvement of the hemolytic performance. The a-C:H:F film coating is thus expected to be utilized in medical technology as a surface coating technology for artificial heart blood pumps.

Preparation of BiPO4/graphene photoelectrode and its photoelectrocatalyitic performance

In this work, a two-step electrodeposition method was employed to prepare BiPO4 nanorod/reduced graphene oxide/FTO composite electrodes(BiPO4/r GO/FTO). The BiPO4/r GO/FTO composite electrode showed the higher photoelectrocatalytic(PEC) activity for the removal of methyl orange than pure BiPO4, which was 2.8 times higher than that of BiPO4/FTO electrode. The effects of working voltage and BiPO4 deposition time on the degradation efficiency of methyl orange were investigated. The optimum BiPO4 deposition time was 45 min and the optimum working voltage was 1.2 V. The trapping experiments showed that hydroxyl radicals(·OH) and superoxide radicals(·O2-) were the major reactive species in PEC degradation process. The BiPO4/r GO/FTO composite electrode showed the high stability and its methyl orange removal efficiency remained unchanged after four testing cycles. The reasons for the enhanced PEC efficiency of the BiPO4/r GO/FTO composite electrode was ascribed to the broad visible-light absorption range, the rapid transmission of photogenerated charges, and the mixed BiPO4 phase by the introduction of r GO in the composite electrode films.

In-vitro degradation behavior of Mg alloy coated by fluorine doped hydroxyapatite and calcium deficient hydroxyapatite

Fluorine-doped hydroxyapatite(FHA) and calcium deficient hydroxyapatite(CDHA) were coated on the surface biodegradable magnesium alloy using electrochemical deposition(ED) technique. Coating characterization was investigated X-ray diffraction(XRD), Fourier-transformed infrared spectroscopy(FTIR), transmission electron microscopy(TEM), scanni electron microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS). The result shows that nano-FHA coated samp presents nano needle-like structure, which is oriented perpendicular to the surface of the substrate with denser and more unifo layers compared to the nano-CDHA coated sample. The nano-FHA coating shows smaller crystallite size(65 nm) compared to t nano-CDHA coating(95 nm); however, CDHA presents thicker layer(19 μm in thickness) compared to the nano-FHA(15 μm thickness). The corrosion behaviour determined by polarization, immersion and hydrogen evolution tests indicates that the nano-FH and nano-CDHA coatings significantly decrease corrosion rate and induce passivation. The nano-FHA and nano-CDHA coatings c accelerate the formation of bone-like apatite layer and significantly decrease the dissolution rate as compared to the uncoated M alloy. The nano-FHA coating provides effective protection to Mg alloy and presents the highest corrosion resistance. Therefore, t nano-FHA coating on Mg alloy is suggested as a great candidate for orthopaedic applications.

Synthesis of Hierarchical SnO2 Nanowire–TiO2 Nanorod Brushes Anchored to Commercially Available FTO-coated Glass Substrates

Growth of single-crystal Sn O_2 nanowires using a fluorine-doped Sn O_2(FTO) thin film as both the source and substrate is demonstrated for the first time at relatively low temperature(580 °C) which preserves the integrity of the underlying glass support and improves scalability to devices. Furthermore, a microwave hydrothermal process is shown to grow Ti O_2 nanorods on these nanowires to create a hierarchical nanoheterostructure that will lead to efficient photogenerated charge carrier separation and rapid transport of electrons to the substrate. This process simplifies nanowire growth by using commercially available and widely used FTO substrates without the need for an additional upstream Sn source and can be used as a high surface area host structure to many other hierarchical structures.

Fluorine-doped BiVO_(4) photocatalyst: Preferential cleavage of C−N bond for green degradation of glyphosate

With increasing concerns on the environment and human health,the degradation of glyphosate through the formation of less toxic intermediates is of great importance.Among the developed methods for the degradation of glyphosate,photodegradation is a clean and efficient strategy.In this work,we report a new photocatalyst by doping F ion on BiVO_(4) that can efficiently degrade glyphosate and reduce the toxic emissions of aminomethylphosphonic acid(AMPA)through the selective(P)−C−Ncleavage in comparison of BiVO_(4) catalyst.The results demonstrate that the best suppression of AMPA formation was achieved by the catalyst of 0.3F@BiVO_(4) at pH=9(AMPA formation below10%).In situ attenuated total reflectance Fourier transforms infrared(ATR-FTIR)spectroscopy indicates that the adsorption sites of glyphosate on BiVO_(4) and 0.3F@BiVO_(4) are altered due to the difference in electrostatic interactions.Such an absorption alteration leads to the preferential cleavage of the C−Nbond on the N−C−P skeleton,thereby inhibiting the formation of toxic AMPA.These results improve our understanding of the photodegradation process of glyphosate catalyzed by BiVO_(4)-based catalysts and pave a safe way for abiotic degradation of glyphosate.

X-ray Photoelectron Spectra of Fluorine-doped 2223 Phase Bi-base Superconductor

Since the discovery of Bi-base superconductors, investigations on their bonding and electronic configuration have been reported. Koniki et al. discussed the distribution and properties of Bi, Sr and Ca in crystal; Kihida et al. pointed out that the binding energy E of Cu 2p3/2 is unchanged in the Bi-Sr-Cu-O,（Bi,Pb）Sr-Cu-O,

Modification of LiMn_(0.6)Fe_(0.4)PO_(4)lithium-ion battery cathode materials with a fluorine-doped carbon coating

In this study,glucose and NH4F were utilized as sources of carbon and fluorine,respectively,for the synthesis of LiMn_(0.6)Fe_(0.4)PO_(4)(LMFP)nanoscales.These nanoscales were subsequently modified with varying levels of fluorine-doped carbon through co-precipitation and mechanical ball milling processes.The LMFP,incorporating carbon and varying levels of fluoride ions,exhibit higher specific discharge capacities at 0.2 Cand electrochemical characteristics compared to the original LMFP coated solely with carbon.The inclusion of fluorine-doped carbon in the composite material creates numerous pathways for expeditious electron transfer.Moreover,the partial formation of metal fluoride at the interface between the surface of LMFP and the layer of carbon coating doped with fluorine enhances the reduction in the charge-transfer resistance.The modified ferromanganese phosphate cathode material reveals an outstanding discharge capacity displaying a reversible discharge specific capacity value of 131.73 mA h g^(−1)at 10C and 154.6 mA h g^(−1)at 0.2C,due to its unique structure.

Boosting faradaic efficiency of CO_(2)electroreduction to CO for Fe-NC single-site catalysts by stabilizing Fe^(3+)sites via F-doping

The atomically dispersed Fe^(3+)sites of Fe-N-C single-site catalysts(SSCs)are demonstrated as the active sites for CO_(2)electroreduction(CO_(2)RR)to CO but suffer from the reduction to Fe^(2+)at~−0.5 V,accompanied by the drop of CO faradaic efficiency(FECO)and deterioration of partial current(JCO).Herein,we report the construction of F-doped Fe-N-C SSCs and the electron-withdrawing character of fluorine could stabilize Fe3+sites,which promotes the FECO from the volcano-like highest value(88.2%@−0.40 V)to the high plateau(>88.5%@−0.40-−0.60 V),with a much-increased JCO(from 3.24 to 11.23 mA·cm^(−2)).The enhancement is ascribed to the thermodynamically facilitated CO_(2)RR and suppressed competing hydrogen evolution reaction,as well as the kinetically increased electroactive surface area and improved charge transfer,due to the stabilized Fe^(3+)sites and enriched defects by fluorine doping.This finding provides an efficient strategy to enhance the CO_(2)RR performance of Fe-N-C SSCs by stabilizing Fe^(3+).

Uniform and Homogeneous Growth of Copper Nanoparticles on Electrophoretically Deposited Carbon Nanotubes Electrode for Nonenzymatic Glucose Sensor

The multiwalled carbon nanotubes thin-film-based electrode was fabricated by electrophoretic deposition and modified with copper （Cu） nanoparticles to fabricate Cu/CNTs nanocomposite sensor for nonenzymatic glucose detection. The expensive glassy carbon electrode was replaced by fluorine-doped tin oxide glass containing CNTs film to confine the Cu nanoparticles growth by electrodeposition through cyclic voltammetry （CV）. The ultraviolet visible and X-ray diffraction analysis revealed the successful deposition of Cu nanoparticles on the CNTs-modified electrode. The atomic force microscopy images confirrqed the morphology of electrodeposited Cu on CNTs film as uniformly dispersed particles. The electrocatalytic activity of electrode to the glucose oxidation was investigated in alkaline medium by CV and amperometric measurements. The fabricated sensor exhibited a fast response time of less than 5 s and the sensitivity of 314 μA rnM^-1 cm^-2 with linear concentration range （0.02-3.0 mM） having detection limit 10.0 μM. Due to simple preparation of sensor, Cu/CNTs nanocomposite electrodes are a suitable candidate for reliable determination of glucose with good stability.

Preparation and Photoelectric Properties of Patterned Ag Nanoparticles on FTO/Glass Substrate by Laser Etching and Driving Layer Strategy

An effective method based on laser etching and driving layer strategy was proposed to prepare patterned Ag nanoparticles(Ag NPs)on fluorine-doped tin oxide(FTO)/glass substrate and thus to enhance the photoelectric properties.This method successively included depositing an aluminum-doped zinc oxide(AZO)driving layer,laser etching,depositing an Ag layer,furnace annealing and laser removal.Different AZO and Ag layer thicknesses were adopted,and the surface morphology,crystal structure and photoelectric properties were investigated.An Ag NPs/FTO/glass sample without an AZO driving layer was prepared for comparison.It was found that furnace annealing of the Ag layer combined with the AZO driving layer,rather than that without the AZO driving layer,was more conducive to generating patterned Ag NPs.Using a 20-nmthick AZO layer and a 150-nm-thick Ag layer led to the formation of uniformly distributed Ag NPs being aligned along the laser-etched grooves to form a pattern.The as-obtained sample had the best comprehensive photoelectric property with an average transmittance of 79.95%,a sheet resistance of 7.11Ω/sq and the highest figure of merit of 1.50×10^(-2)Ω^(-1),confirming the feasibility of the proposed method and providing enlightenment for related researches of transparent conductive oxide-based films.