DE2656472A1 - CHALCOGENIDES AND PROCESS FOR THEIR PRODUCTION - Google Patents

Description

Chalcogenides and processes for their preparation

The invention relates to chalcogenides of the transition metals Groups IVb and Vb as well as molybdenum and tungsten having a certain crystallite size and a method for their Manufacturing.

The di- and polychalcogenides of the transition metals of groups IVb and Vb (side groups) as well as of molybdenum and tungsten with the general formula MX, in which M titanium, zirconium, hafnium, vanadium, niobium, tantalum, molybdenum or tungsten, X sulfur, selenium or tellurium and y is a number from about 2 to 4, were hitherto, if a production was possible at all, - by reactions manufactured at high temperatures. These di- and polychalcogenides are special due to their strongly pronounced anisotropic properties and their storage capacities Interest. Inclusion compounds of various chalcogenides are suitable as lubricants, battery cathodes and superconductors

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(See U.S. Patent 3,766,064). A major obstacle to use however, such chalcogenides are difficult to manufacture. These compounds with the general formula MX ^ cannot be produced in aqueous solution because the ions M '' have a strong tendency to hydrolysis or to form oxo complexes (Cotton and Wilkenson, "Advanced Inorganic Chemistry", 2nd Edition, Interscience, New York, 1966).

In comparison, the precipitation of solids from solutions at low temperatures has the advantage that the costs are low and also the precipitation of a wide variety of products with a wide variety of properties other ways are not accessible is possible.

The invention therefore relates to the production of finely divided stoichiometrically composed di- and poly chalcogenides with a large surface area and small crystallite diameters in the range of 0.1 u (1000 Å) and preferably less than 0.05 u (500 Å) with the general Formula MX, in which M is a transition metal from groups IVb and Vb as well as molybdenum or tungsten, X is a chalcogen, namely sulfur, selenium or tellurium and y is a number from about 2 to 4. The preparation of these compounds by precipitation at low temperatures from non-aqueous solutions

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- V-

Mixtures of salts of the transition metals mentioned. the anions usually being halides, acetate, carboxylate, perfluorocarboxylate, acetylacetonate, hexafluoroacetonate, sulfate, nitrate, and preferably chloride, with solutions or slurries of substances that provide sulfide, selenide or telluride ions. The products of the non-aqueous precipitation at low temperatures differ from the materials of the prior art produced at high temperatures (higher than 400 ° C.) by considerable differences in terms of surface area and crystal properties. A number of compounds of the general formula MX, in which M, X and y have the meaning given above, which cannot be prepared by the known aqueous or high-temperature processes, can be obtained by the non-aqueous process according to the invention at low temperatures. An example of such a connection is VS-, which cannot be established using known methods. Compounds preferred according to the invention are TiS-, ZrS-, HfS-, VS ₂ , NbS ₂ , TaS ₂ and MoS ₃ .

The production of di- and polychalcogenides and stoichiometric Di- and polychalcogenides takes place according to the process according to the invention by using a non-aqueous reactive Produces a solution or slurry which firstly contains a transition metal salt, wherein the transition metal is one of the groups

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IVb and Vb as well as molybdenum or tungsten and the anion is halide, acetate, carboxylate, perfluorocarboxylate, acetylacetonate or hexafluoroacetylacetonate, secondly a source of sulphide, selenide and / or telluride ions, with Li-S, hydrogen sulphide as a source for the chalcogen ions how. MaHS and NH.HS, (SiH ₄ ) ₂ S, Ha ₂ S, 1.X ₂ Se, Li ₃ Te, (MH ₄ I ₃ Se, (KlH ₃ J ₂ S, (R, R'HiH ₂ ) ₂ S and CR, R ' _r R "MHi ₂ S are suitable, where R, R ¹ and R" are identical or different CC _1n and preferably C ₁₁ -C ₀ alkyl radicals or

ü TO t ο

Cg-C _30, and preferably ^c g ~ C- | 2 ^Är y ^lreste are, and third, a non-aqueous solvent, namely C - C_-ether, acetonitrile, benzonitrile, dimethylformamide (DMF), 1,2-Dimethoxyäthanpropylencarbonafc, C ^ - C-- and preferably C, - C ..-- aromatics, ammonia, molten sulfur bis-C2-niethoxyethyl ether f diglyme) _r sulfur dioxide, ethyl acetate, C.-Cg ester, suIfoian, tributyl phosphate, anhydrous acids such as formic acid, glacial acetic acid, C, -C ~ _n - and preferably C ₁ -Cj - Slky! halides, C _fi -C ~ _- and preferably C -.- C.-j-Hrylhalogenide, pyridine, propionitrile, M- _{Methylformamide, dimethyl sulfite, C 1} -C, C - and preferably C 1 -C -, - Amines and / or C 1 -C 4 - and preferably C 1 -C 6 alkanes. The solvents of choice are tetrahydrofuran (THF), dimethylformamide (DMF), chlorobenzene, chloroform, pyridine and acetone. Alternatively, the reaction can be carried out without any solvent. The reaction proceeds spontaneously when mixed at low temperature, preferably less than 400 ° C. but higher than -78 ° C., and atmospheric pressure. The products can

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by filtering, washing with excess solvents or by pumping out the anion salts if they are volatile are to be isolated. In those cases where the sources supplying the sulfide, selenide and / or telluride ions do Are solutions, is not an additional factor for carrying out the reaction Solvent required, although not aqueous Solvent (i.e. a solvent that does not offer or accept protons) can be added to the isolation of the product.

The desired compounds are formed according to the following Reaction:

MZ. + 2A ₉ X

4 2 solution SKiX ttel 2 *

M = transition metal of groups IVb and Vb as well as molybdenum or tungsten; Ä = alkali metal, Ke ₄ ⁺ , R, R ', R "BfH ⁺ , E ₁₁ R ¹ MH ₂ ⁺ or

another of the above cations; % = suitable anion such as Cl, Br, I, acetate, carboxylate mitrate, etc. as stated above; X = sulfur, selenium or tellurium.

As transition metal compounds, all suitable

+ 2— * ■ +5 bonds are used, the M and preferably

+4 +5
M and M deliver. Complexes formed in solution, which as

+4 solids can also be isolated as M source be used. In some cases, such as with niobium and

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Tantalum, a pentavalent salt can be used directly,

+5 +4
since M to M, for example, according to the following equation

is reduced:

NbCl ₅ + 2.5 Li ₂ S - ^ NbS ₂ ^ + 5LiCl + 0.5 S

The transition metal salts are, although not necessarily so, desirably soluble in organic solvents such as THF, although the reaction can in all cases also be carried out without the addition of a solvent. Therefore the solution concentrations are not critical. Suitable anions are halides such as fluoride, chloride, bromide and iodide, acetates, carboxylates, perfluorocarboxylates, amines, acetylacetonates, hexafluoroacetylacetonates, nitrates and sulfates, the carbon-containing portion of the anion being in all cases a C ₁ -Cq and preferably a C ₁ -C ^ hydrocarbon or fluorocarbon radical.

The reaction will usually, but not necessarily, take place in the absence of an excess of sulfide, selenide, or telluride although other starting materials may be present in excess. Since the particle size of Depending on the mixing speed of the reagents, the reaction can take place quickly, i.e. instantaneously, by one of the reaction solution the entire amount of a reaction

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participant adds all at once and thus a finely divided product is obtained, or the reaction can be carried out over a period of
several days by continuously adding measured small amounts of a reactant to the reaction solution.

The reaction temperature can be -78 to 400 ° C, preferably 0 to 400 ° C and best between room temperature (25 ° C) and 300 C. These temperatures are considerably lower than those used in the manufacture of dichalcogenides are required in the solid phase or in the gas phase. The latter are usually up to 1000 C and above.

The products obtained by the non-aqueous precipitation at low temperatures are di- and polychalcogenides,
especially dichalcogenides and mainly disulfides and
have unique properties. The products can
also be composed stoichiometrically. According to the known high-temperature processes, for example, stoichiometric NbS _{2 can be produced with} difficulty or not at all and stoichiometric VS ₂ cannot be produced at all. The particle size and the crystal properties of these materials can be varied within a wide range by the process according to the invention. Small single crystals or powders with a large surface area can be produced
which appear amorphous on X-ray diffraction,

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which indicates a crystallite size of less than 0.05, u (500 R), The surface can be enlarged until the dichalcogenides remain suspended in the solution and become homogeneous dispersions form. This effect can be increased by adding a larger amount of polar non-aqueous Solvents such as DMF or basic solvents such as pyridine are used, which tend to adhere to the To deposit sulfur layers and thereby cause dispersion. The same solvents tend to get in to incorporate crystalline dichalcogenides of transition metals (see US Pat. No. 3,766,064, which lists such intercalation compounds contains). Such dispersions can be gelled or gelled by changing the conditions appropriately basic substrates such as CaO are adsorbed. Those produced by the process of the invention Materials are suitable as electrodes, catalysts and for the production of intercalation compounds, which in turn can be used as lubricants and superconductors.

The manufacturing process described enables connections in a wide range in terms of particle size, crystal properties and surface area. For example, solids can be produced with the following properties:

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A. Large surface area, small particle size, and amorphous crystallinity. Such properties can be achieved by using a solvent which is capable of forming intercalation complexes with the chalcogenide. Alternatively, chalcogenides produced without a solvent or in the absence of a storable solvent can be treated with a storable compound so that the same result is achieved. Such storable compounds can include strong Lewis bases such as pyridine, ammonia, C ₁ -C “-amines, aldehydes, ketones, amides, heterocyclic bases, amidines, anilines and ethers. The chalcogenide containing these intercalations is then subjected to a heat treatment at 75 to 200 ° C., the intercalated solvent, if necessary, being pumped off under vacuum, so that an amorphous chalcogenide with a high surface area and small particle size remains. Example: TiS- made from THF solution and treated with pyridine (the embedded pyridine is expelled at 150 C) was found to be amorphous on the basis of X-ray diffraction studies, which has a crystallite size of at least less than 0.1 u and a BET surface area of 100 m / g indicates.

B. Small surface area, small particle size and amorphous crystallinity. Example: The same TiS ~ as mentioned in (A),

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was found to be amorphous and untreated with pyridine

had a BET surface area of 10 m / g.

C. Low surface area, medium particle size and high crystallinity. Example: Prepared under reflux in acetonitrile TiSp gave a TiS »X-ray diffraction diagrairan. the The crystallinity of all materials can be further improved by tempering the products.

D. Homogeneous dispersion: The conditions can be adjusted so that all or part of the dichalcogenide as homogeneous dispersion remains in suspension. Such materials can be removed by adding a basic solid such as CaO will. Example: TiS produced in propylene carbonate results in a dark brown, opaque dispersion. That TiSp can be absorbed by mixing the dispersion with CaO, which is dark brown after drying, shake. Accordingly, the starting solution is clear after the treatment with CaO.

E. Mixture with a large surface area: dicha / lcogenide / metal oxide. Composite materials can be made by absorbing di- or polychalcogenides onto a metal oxide. This absorption occurs due to the Lewis acid properties of the chalcogenide. Example: The TiS ^ / CaO material used in Example D has been described.

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F. Gels and Glasses: The Dichalcogenides of the Invention containing gels can be obtained by preparation in certain amines such as trihexylamine. The gels so produced result in glasses when the solvents are removed. Example: See example 8.

Precipitation from non-aqueous solutions leads to the formation of stoichiometric products and causes reactions Formation of insoluble precipitates, which are incomplete at higher temperatures in aqueous or solid systems expire.

For example, TiS ₂ can be produced at 450 ° C. to 600 ° C. by reacting TiCl ₄ and H ~ S in the gas phase. At lower temperatures, however, the conversion decreases because the reaction is reversible.

TiCl ₄ + H ₂ S = ^ T ± S ₂ + 4 HCl

H ₃ S is therefore not a practically usable suIfidierungsmittel at temperatures below 400 ° C.

However, if the reaction is carried out in a non-aqueous solution at a low temperature, the reaction will go through Formation of insoluble precipitates irreversible and leads

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quantitative to TiSp. The presence of a chalcogen salt as an intermediate compound is important because at room temperature by a solution of TiCl. H „S flowing through does not result in any reaction. However, if NH ₃ -GaS is first introduced into the solution, the passage of H ₃ S through the ammonia-rich solution leads to the precipitation of TiS-. This is due to the formation of (NH ₄ ) -S or (NH.) HS as an intermediate. As a by-product, (NH.) Cl is formed due to the ion exchange that takes place. So NH ₃ acts as a reaction mediator, although (NH ₄ ) ~ S is not necessarily really isolated. If NH ₃ and H ₃ S are first reacted with one another, the salt required as an intermediate product is also formed.

The product with the formula MX, in which M and X have the meanings given above and y is about 2 to 4 inclusive and preferably 2, is of the anion salts formed at the same time by filtering and using an excess of solvent or by pumping off the anion salt, if this is volatile, separated. If LiCl is the co-precipitated anion salt, it can be dissolved by excess solvent. If NH.Cl is the coproduct, it can be removed by pumping out in vacuo or by washing out. Pumping down can, however, result in a greater or lesser degree of sulfur being removed from the crystal lattice. VS ₂ to

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Example is not stable at higher temperatures. Pumping down for cleaning applied to VS ~ at 15OC leads to the removal of sulfur, which is present according to the 1: 2 stoichiometry of VS ₂ . In this way there is a possibility of producing compounds with a larger surface and a sulfur deficit.

When the excess solvent used and that at the same time coproduct formed are not removed from the compounds with the formula MX, the combination of all of these results

Components of a battery system in which the coproducts can act as an electrolyte.

In a system for producing TiS ₂ as a product, for example, TiCl ₄ and a sulfur source such as Li "S are present as starting materials. Typically, the electrolyte contains the lithium salt of a strong acid (anion = PF _fi , BF ₄ , SO ₃ CF ₃ , etc.) in an organic solvent such as DME, dioxolane or other ethers, as well as mixtures thereof, the salt being required is sufficiently soluble in the solvent to function as a good Li conductor. That

Ti salt with the desired electrolyte anion (PFg _r BF.,

SO ₃ CF ₃ , Cl ", Br", J ~, ClO ₄ ") is brought into contact with the Li" S in the organic solvent used in the electrolyte, so that TiS- (for use in the manufacture of the

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active cathode) and as a coproduct LiY (Y = electrolyte anion) can be obtained in the organic solvent. Through this Procedure are both the cathode material and the Electrolyte produced at the same time. Impurities from the solution inhibit the effect of the precipitate (in this case TiS-) not, but actually lead to an improvement, since the wetting of the cathode by the electrolyte is desirable.

The invention can be represented for the TiCl ₄ system by the following equation. It should be noted, however, that this equation is also relevant for the preparation of compounds with the general formula MX in other systems.

organic
TiCl ₄ + 4HY + 2Li ₉ S solvent TiS ₉ + 4LiY / organic

* "Solvent + 4HC1

Cathode electrolyte (Y = PF ₆ ", BF ₄ ", SO ₃ CF ₃ ")

A battery is obtained by suitable treatment of the TiS ₉ to produce a cathode and by inserting an anode (such as Li).

Examples

All preparative work described in the following examples was carried out either in a dry box or under stick

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* 9.0-

fabric carried out. Both the starting metal compounds (+4) and (+5) as well as the sulfides and selenides obtained are sensitive to moisture and oxygen. This is especially true for the finely divided powders which are obtained by the heterogeneous precipitation by the process according to the invention. All solvents were dried according to standard procedures prior to use and the reagents were always anhydrous used.

example 1

Production of TiS ₂ (ZrS ₂ , HfS ₂ and VS ₃ )

In this example, TiCl. used. It has been found that the process with ZrCl., HfCl., MoCl ₄ or VCl. worked just as well. A solution of 10 millimoles of TiCl. (1.9 g) in tetrahydrofuran (75 ml) was made up in a dry box (TiCl. Is not stable in the presence of air or moisture). 0.96 g (20 millimoles) of lithium sulfide were added to this solution with stirring at room temperature. The yellowish solution immediately began to turn dark in color. The reaction was allowed to proceed for several hours, although the reaction was essentially complete in one hour. The resulting dark brown solid was filtered off and washed with 10 ml of THF. After evaporation of the solvent, 83% of the theoretical yield of lithium chloride was isolated from the combined filtrates. An elemental analysis of the

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dark brown powder that remained after drying gave that it was TiS ", 1/2 mole of the solvent Tetrahydrofuran and less than 5 wt.% LiCl contained. The analytical results of the other compounds produced are included in the table below.

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Table 1

Analyzes

ITiS ₂ (LiCl.3THF) _{0 25}

Ti S. Li Cl C. H 39 calculated 27 _f 18 36.23 1.00 5.02 20.38 ³ , 93 found 27.37 36.19 1.27 4.41 16.73 2,

oo - BET surface area 14.2 m ^z / g MOS.

Mon

38.37

31 _f 02

(something not implemented
Li _? S available)

NbS,

Nb

S = *> NbS

relationship

VS-

36, 82 24, 89 V S. ²⁷ r 50 34, 70

^VS

2 _f 0

The solvent could be removed by heating and pumping off. The product thus obtained absorbed one molar equivalent Ammonia in about 5 minutes (TiS produced in the conventional way "absorbs the same amount of ammonia over a period of days or weeks). Due to the small crystal size (<C0.1, u) no X-ray diffraction

2 diagram received. The BET surface area was about 10 m / g and could by treating with pyridine, filtering and pumping

of pyridine can be increased to about 100 m / g.

Instead of tetrahydrofuran, acetonitrile, propylene carbonate, acetic acid and dimethylformamide could also be used as solvents (DMF) or no solvent at all (test carried out in excess TiCl.) Can be used. In DMF and propylene carbonate In addition to the precipitated solid, a dispersion resulted.

When lithium sulfide was replaced by sodium sulfide, required the reaction at room temperature takes a lot longer. Removal of the by-product, sodium chloride, from the dark TiS "was achieved by washing with 12% acetic acid. Alternatively, ammonium sulfide could be used as the sulfide source, which was obtained in situ by adding an excess beforehand of ammonia to the TiCl. solution in tetrahydrofuran and

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- VST-

subsequent passage of hydrogen sulfide was made. The by-product obtained in this case, ammonium chloride, could be removed by sublimation at 150 ° C and 0.1 Torr will.

If the crystallinity of the product is to be improved, the dry powder can be partially tempered by leaving it for several days at a temperature of 400 ° C or less heated in an inert atmosphere. According to this process, a product was obtained which had an X-ray diffraction pattern typical of TiS revealed.

Another way of improving the crystallinity of the product is to use a Soxhlet extraction device by placing the Li S in an extraction thimble over a refluxing solution of TiCline tetrahydrofuran. With this procedure, platelet-shaped TiS ₃ crystals formed in the lower solution after several days.

The infrared spectra provide further confirmation of the correctness of the specified product compositions. For example, the infrared spectrum for TiS ₂ obtained in the manner described is essentially identical to that of a sample of TiS ₂ / that from Alfa Inorganics

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was obtained. The latter shows a broad band with a band center at 400 cm due to the Ti-S bond. The product of TiCl ₄ and Li ₂ S has a less broad band

-1

at 375 cm , the band width due to the smaller

Crystal size is reduced.

Example 2

Production of TiS ₃ (ZrS ₃ , ^HFS ₂ ^umi

As a starting material TiCl ₄ was used, but the process worked equally well with ZrCl _4, HfCl ₄ or VCl. ₄ 300 ml of a 0.2 M TiCl ₄ solution in acetonitrile were added slowly (one drop / second) to a 0 _f 6 M Li "S solution in acetonitrile which was boiling under reflux. The solution was cooled, filtered and washed with methanol to remove any LiCl which had formed. Then it was washed with ether and Has product was then dried in a dry box in a Buchner funnel. The resulting product was golden brown and. resulted in the X-ray diffraction diagram typical of TiS, without the need for further treatment.

Example 3

Production of NbS (TaS ₃ )

The procedure described below is applicable to such transition metals of group Vb, the pentahalides

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_ yes_ »-

(Niobium and tantalum). The procedure is in this example carried out with Kxobpentachlorid.

To a solution of 10 millimoles of NbCl ₅ (2.68 g) in 50 ml of tetrahydrofuran was added 1.15 g of lithium sulfide (25 millimoles) and the reaction was left to stir overnight in a dry box. The dark product obtained after filtration contained 60% by weight of NbS _{1 Q} _.

Example 4 Manufacture of molybdenum disulphide

After adding 10 millimoles of molybdenum tetrachloria and 20 millimoles Lithium sulfide to 30 ml of THF with stirring a fine black solid was obtained, which after filtration and drying 70 wt.% MaS ~ contained. Most of the remaining weight (60%} is attributable to the solvent, the can be removed by heating to about 150 ° C. and pumping out at a pressure of 1 torr.

Example 5 Stable homogeneous dispersions

If the reactions are carried out TiCl, 4- A ~ S in suitable media stable homogeneous dispersions of TiS in the liquid are obtained (either with or without

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precipitated solid). For example, if propylene carbonate (PC) is used as a solvent, the floating phase above is a dark brown, opaque dispersion that occurs when Filtration through a medium frit remains unchanged and does not change over a period of weeks and months settles. Alternatively, if in addition to a non-dispersing solvent such as THF, a dispersing active solvent such as pyridine or alkylamines is present in the starting solution, likewise a corresponding one Dispersion obtained. Murphy and Hull (J. Chem. Phys, 62, (1975)) have dispersions of TaS "in aqueous media described, which, however, are much less stable due to the hydrolytic decomposition of the sulfide by water. In Such decomposition does not occur in non-aqueous solutions such as those according to the invention and the dispersions are over Months stable.

The reaction of a solution of TiCl. in excess trihexylamine and tetrahydrofuran with hydrogen sulfide provides another example of a method of dispersing of the obtained TiS in the solvent medium. The amine present in the reaction solution serves to reduce the extreme to disperse fine particles of the product. The dichalcogenides formed in such dispersions can be applied to materials with a large surface such as coals, refractory oxides and basic or acidic solids such as CaO, MgO, Al "0-, and silicon

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oxide-aluminum oxide are absorbed, with the solution im Becomes clear over time.

Example 6 Metal-rich products of vanadium and niobium

Attempts to produce stoichiometric disulfides of vanadium and niobium by high-temperature processes (> -400 ° C) result in metal-rich products due to the vapor pressure of sulfur at elevated temperatures. The process according to the invention carried out at room temperature gives essentially stoichiometric products (sulfur to metal such as 2: 1). A proof of this is in addition to the analysis of the behavior of the products when heated to 10O ⁰ C, sulfur escapes and settles visible on the colder parts of the vessel.

Example 7

Potential of a TiS »electrode (currentless measurement, open circuit)

1 g of TiS ₂ , which was produced in THF by the process according to the invention, was pressed into an aluminum mesh to produce a cathode. The potential of this cathode (open circuit) was measured against Li ° in a LiClO / THF / DME electrolyte and was found to be 2.55 volts. The potential fell to 1.80 volts during discharge and could be increased by charging

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be restored to the original value. These potentials correspond to those of TiS ₂ (2.55 Volt); and LiTi CT, 80 volts), and are, further evidence of the composition according to the formula

Example 8 TiSy-GeI- and -G ^

40; mMöl trihexylamine ml in 25 of tetrahydrofuran were added 10 mMöl ₄ "then placed for 5 minutes anhydrous hydrogen sulphide in an amount of about 1 to 5 cc / second through the solution. During this time the. Solution dark xm & something; viskoserv The dark mixture was then left to stand at room temperature. _: There was a

Si SeJI ^ that when pumping, and heating, to more than 3 (30 / C a few scraps of grass-like residue resulted in no

eatgafe »Hurry. Electron scanning microscopy

ieigjte ^ älmB döis> EEetdtoOkt a GOLaispfease waar ,, undi X-ray

m litani xmM

/ C

BeslspaeflL S)

I cPiJ cshal ^ eaagendldie sändJ. known that they are firamandiafe nHJEtter: KildhiEiaagj worn 11E1J-Eanixdlufeten>afcserfeiieren; CTüSH & S 35 Ί & 6) (U & 41)) "IDJie AVEEnajMiie ^ esGihwiniddlgjfeeiLfc häMgjfc wst the Qbear— this; ffesfceni BilcAaillecigjemiyis afe ((if-fimmonuiaikdampf bei

Normal conditions is used). TiS with a particle size 100 mesh, for example, takes several days to fully react with ammonia. According to example T T ± S "produced absorbed T moles of ammonia in five minutes (further ammonia was not absorbed) when it was mixed with ammonia vapor under normal conditions in a gas burette in Contact was made.

Example 10 Reaction with n-butyllithium

A general reaction of the dichalcogenides of the transition metals of groups ZVb and Vb is the formation of adducts with lithium when using n-butyllithium. According to the invention Disulfide products obtained from the process reacted very quickly with n-butyllithium to form such adducts:

Reaction product Li absorption by n-butyl lithium TiS ₂ 1.09

VS ₂ 1.48

Example. 1! T

Use of VS produced according to the invention as a cathode in a; Egg — battery

S ~ is not known as: stoichiometric compound and knew after, the conventional process not made "Kin such according to the method according to the invention ever

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but producible material was reacted with n-butyllithium to a composition Li VS “(O <X <1.5). The starting material had a sulfur to vanadium ratio of 2: 1. _{The VS 2} used as the starting material has a potential (open circuit) of about 2.45 volts and the lithium-containing material has a potential of 1.80 volts against lithium. The reaction of n-butyllithium (Whittingham & Dines, Mat. Res. Bull K) / 287 (1975)) and the favorable potential (charged / discharged) make VS ₂ / LiVS ₂ an attractive cathode material.

Manufactured in the past and characterized as VS " Vanadium sulfide compounds were all produced using high temperature processes, that means manufactured at over 400 ° C.

Experiments conducted as part of the development of the present invention have shown that the high temperature production of vanadium _{sulfides gives compounds of the formulas V 1} -Sq, VjS, etc., rather than VS ".

It has been found that vanadium sulfide compounds other than VS _? react only with a maximum of 0.2 m n-butyllithium.

Such materials cannot be used as battery cathodes because the low lithium uptake is very strong

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affects the potential and the charge / discharge capabilities.

However, vanadium sulfides produced by the process according to the invention have the formula VS- and, when mixed with n-butyllithium, absorb 1.5 equivalents of lithium. This behavior, which _{corresponds to that of TiS 2 , shows that TiS 1 and VS 2} produced by the process according to the invention correspond both structurally and stoichiometrically and that VS 1 can in fact be produced as such. For VS-held connections, which were produced by conventional high-temperature processes, differ considerably from TiS- and VS ₂ produced according to the invention, which is strong evidence that the connections produced by known processes are not really VS ₂ .

Example 12 Use as a catalyst

NbS- produced according to the invention is a more active catalyst for hydrodesulfurization of dibenzothiophene at the same temperature (400) and the same pressure (31.6 atmospheres) as NbS produced from the elements by conventional methods · Compounds produced according to the invention with Layered grids are therefore more active than all connections made up to now.

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Rate constants

-7 -1 -1 NbS ₂ : made from elements K = 8.7 χ 10 g second;

-7 -1 -1 NbS ₀ : produced according to the invention K = 13 χ 10 g second The same applies to TiS ₂ . VS ₂ was also active as a catalyst. _{As mentioned above, VS 2} cannot be produced by conventional processes.

Example 13 Direct formation of an emplacement complex

Usually, when using large-crystal transition metal dichalcogenides which have been prepared by conventional methods, sterically hindered amines such as 4-t-butylpyridine cannot be intercalated between the layers of the chalcogenides and form inclusion compounds (Gamble et al, Science Vol. 174, 493, 1971 ) _v . However, if such molecules are present during the described precipitation reaction, they will be entrapped in the solid product which forms in situ. If, for example, 5 mmol of 4-t-butylpyridine are present in the THF solution, if 10 mmol of TiS ₂ from TiCl. and Li ₂ S, then the product, a dry dark solid powder, contains the amine.

Example 14

Production of US ₂ under normal conditions (in a dry box)

It became a green solution of 3.70 g of UCl. (10 mmol) in 100 ml

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THF produced. 0.92 g (20 mmol) of Li ₂ S were added to this solution with stirring. The reaction solution turned brown and was stirred for one day at room temperature. After filtering, washing with 20 ml of THF and drying the precipitate, 3.07 g of black powder were obtained (102% yield). An X-ray diffraction record showed no suitable interference lines due to the small particle size.

In the "Handbook of Preparative Inorganic Chemistry", Volume (2nd edition) by G. Brauer (Academic Press, 1965) is on page 1446 the conventional production of US from UCl. + H-S described in detail at 600 to 700 °.

Example 15

Li_Se + ZrCl ₄₁ . ZrSe ₂

To 50 ml of acetonitrile were 10 mmol of zirconium tetrachloride and then added 20 mmol of lithium selenide in several portions with stirring. After stirring for several hours, the solid product became collected on a filter, washed with acetonitrile and dried. 10 mmol of zirconium diselenide were obtained.

Example 16 Polysulfide Preparation

Polysulfides can be made by making the appropriate stoichiometric amount of sulfur together

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with the Li "S is added, so that the corresponding desired Li ₃ S is obtained. Two examples of the production of known polysulfides are given below:

VCl ₄ + 2Li ₂ S ₂ -> · VS ₄ ^ + 4LiCl

TiCl ₄ + Li ₂ S ₂ + Li ₂ S - »> TiS ₃ * + 4LiCl

However, this procedure is not limited to known polysulfides, but provides a way of representation of previously unknown polysulfides such as TiS .. TaS, etc. In addition, the inventive method provides Dispersions, gels, etc. of these materials, whose properties do not depend on the chain-like morphology of the Polysulphides can be mastered.

Example 17

Solvent-free production of crystalline TiS ₃ from NH ₃ , H ₂ S and TiCl ₄

By bubbling NH ₃ and H ₃ S in a three-necked flask, about 5 g of (NH ₄ ) HS or (NH ₄ J ₃ S. To the resulting white solid was added dropwise 3.8 g of TiCl. (20 mmol) A reaction occurred immediately to give a black-brown solid consisting of TiS ₂ + NH.Cl. This black-brown solid was removed from the flask and placed in a 635 cm long quartz tube with a diameter of 20 mm

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transferred, which was melted in vacuo. The quartz tube was exposed to a temperature gradient for a day so that one end of the tube was kept at a temperature of 380 ° C. and the other end of the tube was kept at a temperature of 100 ° C. (NH.) Cl sublimed and condensed at the colder end of the tube, so that separation took place in this way.
The TiS was "tempered" at the hot end of the pipe. The received
Product gave a perfect powder X-ray diffraction record.

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Claims (16)

Claims Chalcogenides with a crystallite size less than 0,1, u and the general formula MX, in which M is a metal from groups IVb and Vb as well as molybdenum or tungsten, X a chalcogen, namely sulfur, selenium or tellurium and y is a number from about 2 to 4. 2. Compound with the formula VS ₂ . 3. Process for the preparation of chalcogenides of the formula MX, in which M is a metal from groups IVb and Vb and Molybdenum or tungsten, X sulfur, selenium or tellurium and is a number from about 2 to 4, characterized in that a transition metal salt, wherein the transition metal is a metal of groups IVb and Vb as well as molybdenum or tungsten, and the anion of the salt is halide, acetate, carboxylate, perfluorocarboxylate, acetylacetonate and / or Hexafluoroacetylacetonate, where the carbon-containing portion of the anion is a C ₁ -C _g hydrocarbon or fluorocarbon, is reacted with a substance providing sulfur, selenium or tellurium at a temperature of 0 to 400 ° C. 709828/1102 ORiGWAL INSPECTED 4. The method according to claim 3, characterized in that the isolated product by contact with an embedment Invalid solvent converts to an intercalation compound of the chalcogenide, then the solvent drives out by heating and thereby wins a chalcogenide with an enlarged surface. 5. The method according to claim 4, characterized in that the storable solvent is pyridine, Ammonia, C. -C ,, -amines, aldehydes, ketones, amides, heterocyclic Bases and amidines are used and the solvent is then stored at a temperature of 75 to 200 ° C. 6. The method according to claim 3 _r, characterized in that a stoichiometric chalcogenide is prepared. 7. The method according to claim. 3, characterized in that the reaction is carried out in the presence of a non-aqueous solvent. 8. The method according to claim 7, characterized in that acetonitrile, benzonitrile, propionitrile, acetone, C.-C ₂ -alkyl halides, 709826/110? C _fi -C "aryl halides, 1,2-dimethoxyethane, diglyme, N-methylformamide, dimethylformamide, C ^ -C ₂₀ aromatics, pyridine, suIfolane, tributyl phosphate, C ₅ -C." Alkanes, C.-Co- Ethers and esters, anhydrous acids, dimethyl sulfate and / or C ₁ -C. Amines are used. 9. The method according to claim 8, characterized in that the anhydrous acids are formic acid and glacial acetic acid used. 10. The method according to claim 3, characterized in that the reaction at a temperature of 25 to 300 C. performs. 11. The method according to claim 3, characterized in that the compound providing sulfur, selenium or tellurium is Li ₃ S, hydrogen sulfide (HS), (NH ₄ J ₃ S, Na ₃ S, Li ₃ Se, Li ₃ Te, (NH ₄ ) ₂ Se, (RNH ₃ J ₂ S, (RR ¹ NH ₂ ) ₂ S and / or (RR ¹ R ¹¹ NH) ₃ S are used, where R, R ¹ and R "are the same or different C ₁ -C - Are alkyl and / or C, -C ₂ aryl groups. 12. The method according to claim 3, characterized in that to produce a product with a small surface area, medium particle size and high crystallinity the isolated product at a temperature above about Tempered at 45O ° C. 709826/1 102 13. The method according to claim 3, characterized in that di- or polychalcogenides can be stored in the presence Prepares compounds, the storable compound in the starting reaction mixture as Solvent is present. 14. Method of simultaneous manufacture of a cathode with the formula MX, in which M is a transition metal of groups IVb and Vb as well as molybdenum and tungsten, X is sulfur, Selenium and / or tellurium and y is a number from about 2 to 4, and electrolytes, characterized in that one (1) a transition metal salt in which the transition metal is a metal of groups IVb and Vb as well as molybdenum or Tungsten and the anion halide, acetate, carboxylate, Perfluorocarboxylate, acetylacetonate and / or hexafluoroacetylacetonate is, wherein the carbon-containing portion of the anion is a C. -Cg hydrocarbon or fluorocarbon radical is mixed with a non-aqueous solvent, (2) the solution obtained is mixed with a strong acid HY in which Y is Cl ", Br ~, J ~, ClO ₄ ", PF ₆ ", BF ₄ " and / or SO ₃ CF ₃ ", and mixed (3) this solution in turn for the production of the MX cathode and the electrolyte LiY with lithium sulfide, lithium selenide and / or telluride mixed at a temperature of 0 to 400 ° C. 709826/1 102 15. Homogeneous dispersions, prepared according to claim 7, of TiS ₂ , VS ₂ , ZrS ₂ , HfS ₂ I, NbS ₂ , TaS ₃ and / or MoS ₃ . 16. Compositions, characterized in that they have a homogeneous dispersion according to claim 13 on a carrier with a large surface, wherein the carrier with high surface area is coal and / or refractory oxide. ue: ka: kö 709828/1102