Cupric Fluoride Research Articles

Rational Design of an Electron/Ion Dual-Conductive Cathode Framework for High-Performance All-Solid-State Lithium Batteries.

All-solid-state lithium batteries (ASSLBs) have been paid increasing attention because of the better security compared with conventional lithium-ion batteries with flammable organic electrolytes. However, the poor ion transport between the cathode materials greatly hinders the capacity performance of ASSLBs. Herein, an electron/ion dual-conductive electrode framework is proposed for superior performance ASSLBs. Highly electronic conductive reduced graphene oxide and carbon nanotubes interconnect with active materials in the cathodes, constructing a three-dimensional continuous electron transport network. The composite electrolyte penetrates into the porous structure of the electrode, forming a consecutive ionic conductive framework. Furthermore, the thin electrolyte film formed on the surface of the cathode effectively lowers the interfacial resistance with the electrolyte membrane. Highly electron/ion conductive electrodes, combined with the polyethylene oxide-Li6.4La3Zr1.4Ta0.6O12 (PEO-LLZTO) composite electrolyte, show excellent capacity performance for both LiFePO4 and sulfur (lithium-sulfur battery) active materials. In addition, the LiFePO4 cathode demonstrates superior capacity performance and rate capability at room temperature. Furthermore, the relationship between the low Coulombic efficiency and Li dendrite growth has been revealed in this work. An effective layer is formed on the surface of Li metal by the simple modification of cupric fluoride (CuF2), which can stabilize the electrolyte/anode interface. Finally, high-performance ASSLBs with high Coulombic efficiency can be achieved.

HeI and HeII photoelectron spectra of CuF and CuF 2

The HeI and HeII photoelectron spectra of cupric fluoride vapour have been recorded using a pseudo-molecular-beam technique Features due to the presence of both CuF and CuF 2 have been identified An analysis of these features in terms of the electronic structure of CuF and CuF 2 is proposed.

Surface reduction of solid 3d transition metal compounds during x-ray photoelectron spectroscopy

Abstract Pronounced surface reduction of some 3d transition metal compounds has been observed during measurements with an AEI ES200 X-ray photoelectron spectrometer. Systematic data indicate that the degree of reduction in a given compound does not depend on temperature, vacuum pressure or X-ray flux, but is a function only of the integrated X-ray dose. Particularly strong effects were found in cupric fluoride and potassium ferricyanide.

Lithium Anode Cells Operating at Room Temperature in Inorganic Electrolytic Solutions

Lithium anode electrochemical cells have been operated at room temperature using electrolytic solutions of lithium salts in inorganic solvents such as phosphorus oxychloride, thionyl chloride, and sulfuryl chloride. Lithium metal can be electrodeposited from these solutions accompanied, in the case of chlorine‐containing electrolytes, by the simultaneous electrogeneration of chlorine at the positive electrode. The resulting lithium/chlorine electrochemical cells have open‐circuit potentials of 4.0–4.3V, depending on the presence of excess Lewis acid in the electrolyte. The solvents are compatible with both lithium metal and with strong oxidants including chlorine (Cl2), cupric fluoride , polycarbon monofluoride , and tungsten trioxide which can be used as cathode materials. The solvents themselves, while difficult to oxidize, can be electrochemically reduced at various catalytic surfaces (such as carbon black and metals) and act as cathode depolarizers. This catalytic solvent reduction process leads to cells with exceptionally stable voltages and energy densities in excess of 500 W‐hr/kg.

Configuration of the Water Molecule in Cupric Fluoride Dihydrate at 298°K

The crystal structure of cupric fluoride dihydrate at 298°K has been redetermined from three-dimensional, single crystal, neutron diffraction data. Least-squares refinement of 163 independent, observed reflections gave a final, weighted R index Rw = 0.038. The H–O–H angle in the water molecule is 110.6° ± 0.2°, which, in contrast to the value 115.5° ± 0.4° found in an earlier study, is not significantly different from the tetrahedral angle of 109.5°. Thermal vibration is highly anisotropic, with much larger amplitudes perpendicular to infinite, hydrogen-bonded sheets than parallel to the sheets.

Physicochemical investigation of systems based on cupric fluoride

1. The systems MF-CuF2-H2O (M-Na, K, Rb, Cs) were studied by the method of isothermal solubility. 2. In the systems MF-CuF2-H2O (M-K, Rb, Cs) phases of variable composition and two individual compounds of the type of M2CuF4 and MCuF3 are formed. The solid phases of the system NaF-CuF2-H2O are represented only by phases of variable composition. 3. The phases of variable composition of the systems MF-CuF2-H2O are solid solutions.

Crystal and Magnetic Structure of Cupric Fluoride Dihydrate at 4.2°K

A neutron diffraction study of CuF2·2H2O below the Néel point has determined the crystal and magnetic structure. As compared with this crystal at 298°K, the long Cu–F axial bonds of the distorted octahedron around the Cu2+ ion are reduced in length from 2.465±6 to 2.391±4 A: the short Cu–F bond of 1.899±6 A and the Cu–O bond of 1.945±4 A are unchanged. The H–O–H angle is reduced from 115.5° at 298°K to 110.1±0.4° at 4.2°K, and the O–H distance from 0.980±7 to 0.959±5 A. The amplitudes of vibrational displacement of the Cu, O, and F atoms at 4.2°K are about one-half that at 298°K: The hydrogen atoms have about the same motion, due to zero-point energy. The magnetic unit cell is identical with the nuclear cell, but the spin on the body-centered copper atom is antiparallel to that at the origin. The spin direction is very nearly along the c axis, although an alternative model with the spin along the long octahedral direction fits the magnetic scattering almost as well. The difference between the Néel temperature of 10.9° and that of 26°K at which the magnetic susceptibility is a maximum is consistent with the observed magnetic structure. The revised nuclear scattering length for fluorine of 0.529×10—12 cm found in the analysis of CuF2·2H2O at 298°K is in excellent agreement with the experimental value of 0.534±12 obtained in the present study.

Crystal Structure of Cupric Fluoride Dihydrate at 298°K

A neutron determination of the crystal structure of cupric fluoride dihydrate at 298°K has been made. The structure consists of puckered sheets of nearly square CuF2O2 groups, linked together by hydrogen bonds of 2.715±6 A, with the sheets connected by longer Cu–F bonds to form distorted octahedra around the Cu2+ ions. Dimensions within the octahedra are, two Cu–O distances of 1.941±5, two Cu–F of 1.898±8 and two Cu–F of 2.465±6 A. The long F–Cu–F axis is inclined at 7½° from the normal to the plane containing the remaining CuF2O2 group of the octahedron. The Cu–O bonds bisect the H–O–H angle of 115.5±0.4°. The O–H bond is 0.980±7 A and the O–H···F angle is 164.9±0.7°. The amplitudes of thermal displacement of the atoms along various directions are given. The nuclear scattering length of fluorine is revised to 0.529±13 (10—12 cm).

The dissociation of nitric oxide-copper(II) halide complexes in alcohols. The preparation of the copper(II) fluoride nitrosyl

The stability of the complexes formed between nitric oxide and cupric chloride and bromide in a series of alcohols has been studied. When cupric chloride is used, there is an equilibrium NO + CuCl 2 ⇆ CuCl 2·NO which tends to completion as the molecular weight of the alcohol increases. For the bromide, the reaction NO + CuBr 2 → CuBr 2·NO is complete even in methanol. After formation, both nitrosyls dissociate into ions: CuX 2·NO ⇆ CuX 2 − + NO +. The equilibrium constants for the dissociation of the two nitrosyls decrease in the solvents methanol to 1-butanol, then begin to increase again in 1-pentanol. Experiments based on these observations have made it possible to prepare for the first time the cupric fluoride nitrosyl.

Evidence for a Nitric Oxide Complex with Cupric Fluoride

ALTHOUGH it has been recognized for some time that nitric oxide and cupric chloride or bromide combine in non-aqueous solvents to form nitrosyl complexes1, the composition of these has only recently been determined2. The deep blue colour is due to the covalent CuX 2.NO (possibly solvated) : this compound dissociates into colourless ions : and this has been responsible for erroneous structures suggested for the complexes. Unsuccessful attempts have been made to prepare nitrosyl complexes in alcoholic solution from other cupric salts, including the fluoride3. Recently, a study of the variation of dissociation constant of the cupric chloride nitrosyls as a function of the dielectric constant of the alcohol has been made4 : some results are shown in Table 1.

The copper fluorides: Part I—X-ray and electron microscope examination

X-ray diffraction powder photographs have been used to study the fluorides of copper. Both anhydrous copper fluoride and the dihydrate are slowly converted into a green basic fluoride in atmospheric air. In addition, one other basic fluoride has been observed which is unstable in air. No trace of any compound which might be cuprous fluoride has been obtained, in spite of numerous attempts to make it. Electron diffraction and electron microscope photographs of the corrosion film formed by the action of elementary fluorine on copper at temperatures between 100°C and 500°C have been taken. There is good evidence that the film has a cupric fluoride structure rapidly changing to the basic fluoride on exposure to air. Electron microscope investigations show that copper metal can migrate and crystallize as bulk copper at temperatures as low as 300°C.