Method for preparing solid sulfide material of formula MaLibPcSdXe(I)

Abstract

The present invention relates to a compound represented by formula (I): a Li b P c S d X e (I), (wherein, X represents at least one halogen element; a, b, c, d, and e are real numbers; a represents a number, such that 0≦a<9; b represents 0

Description

Technical Field

[0001] Cross-reference to Related Applications This application claims priority to European Patent Application No. 21306792.9, filed on December 16, 2021, the entire content of which is incorporated herein by reference for all purposes.

[0002] The present invention relates to a new preparation method of a solid sulfide material of formula (I): M a Li b P c S d X e (I) (wherein: - X represents at least one halogen element; - a, b, c, d and e are real numbers; - a represents a number such that 0 ≦ a < 9; - b represents a number such that 0 < b ≦ 9; - 2.0 ≦ a + b ≦ 9; - c represents a number such that 1.0 ≦ c ≦ 3.0; - d represents a number such that 1.0 ≦ d ≦ 11.0; - e represents a number such that 0 < e ≦ 3.0; - M is an alkali metal selected from Na, K, Rb, Cs and Fr) a new preparation method of a solid sulfide material of, as well as products obtained by said method, and in particular its use as a solid electrolyte.

Background Art

[0003] Lithium batteries are used to power portable electronics and electric vehicles because of their high energy and power density. Conventional lithium batteries utilize a liquid electrolyte composed of a lithium salt dissolved in an organic solvent. The aforementioned system poses safety problems because the organic solvent is flammable. When lithium dendrites occur and pass through the liquid electrolyte medium, they can cause a short circuit and generate heat, which can lead to accidents resulting in serious injuries.

[0004] Non-flammable inorganic solid electrolytes offer a solution to safety issues, and their mechanical stability helps inhibit lithium dendrite formation, prevent self-discharge and heating problems, and extend battery life.

[0005] Solid sulfide electrolytes are advantageous for lithium battery applications due to their high ionic conductivity and mechanical properties. These electrolytes can be pelletized and attached to the electrode materials by cold pressing, which eliminates the need for high temperature assembly steps. Eliminating the high temperature sintering step removes one of the challenges to using lithium metal anodes in lithium batteries.

[0006] A problem encountered with solid sulfide electrolytes is the release of hydrogen sulfide (H2S) when the material is in contact with moisture. Hydrogen sulfide has a pungent odor and is toxic; therefore, there is a need for solid sulfide electrolytes with improved chemical stability that release low amounts of H2S.

[0007] Solid sulfides as reported in the literature are generally prepared by high temperature solid-state synthesis or by dry or wet mechanochemical routes. All-solution routes have also been proposed, such as methods starting from preformed solid sulfides dissolved in a solvent such as ethanol.

[0008] Therefore, there is a need for new solid sulfide electrolytes and new methods for preparing solid sulfide electrolytes.

[0009] J. Chen et al. reported in Chem. Lett. 2019, 48, 863-865 that the synthesis of Li2NaPS4 was achieved by the reaction of Na3PS4 with Na + / Li +They show that this can be achieved by ion exchange. However, the authors are silent regarding a similar approach involving halogen-containing sulfide materials. Furthermore, they say nothing about the effect of this ion exchange on the ionic conductivity of the resulting sulfide material, nor about the chemical stability of the resulting material.

[0010] There remains a need for new preparation routes for solid sulfide materials that can be used for the fabrication of sulfide-based solid electrolytes with improved ionic conductivity.

[0011] There is also a need for new preparation routes for solid sulfide materials that can spare or even prevent the use of lithium sulfide, Li2S. Indeed, Li2S is an expensive raw material, difficult to prepare, purify and handle, and for these reasons is not industrially available, let alone in high purity grades.

[0012] There is also a need for new routes to prepare solid sulfide materials that have good chemical stability and exhibit low H2S release, for example, when exposed to humid air. Summary of the Invention

[0013] The present invention relates to a compound of formula M a Li b P c S d X e (I) relates to a new method for preparing a solid sulfide material (A).

[0014] The present invention relates to a compound of formula M obtained by the method of the present invention. a Li b P c S d X e(I) also relates to the solid sulfide material (A). The present invention also relates to the use of such a solid sulfide material (A) as a solid electrolyte. The present invention also relates to a solid electrolyte containing such a solid sulfide material (A) and an electrochemical device containing the solid sulfide material (A) according to the present invention. The present invention also relates to a solid battery containing the solid electrolyte of the present invention and a vehicle containing the solid battery.

[0015] Surprisingly, the inventors have found that the solid sulfide material prepared by the method according to the present invention has improved ionic conductivity when compared with solid sulfide materials having a similar composition but prepared by the above-mentioned conventional methods such as high-temperature solid-phase synthesis or mechanochemical routes. In fact, in the method according to the present invention, the replacement of Na by Li in the Na+-based starting material + by Li + seems to be involved in the high Li + mobility in the resulting solid sulfide material.

[0016] The inventors have also found that the new method according to the present invention advantageously makes it possible to prepare a solid sulfide material having high ionic conductivity while refraining from using lithium sulfide, Li2S, which is an expensive raw material that is difficult to obtain in large quantities especially in high-purity grades.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Accordingly, the present invention provides a compound of formula (I): M a Li b P c S d X e (I) (wherein: - X represents at least one halogen element; - a, b, c, d and e are real numbers; - a represents a number such that 0 ≦ a < 9; - b represents a number such that 0 < b ≦ 9; - 2.0 ≦ a + b ≦ 9; - c represents a number such that 1.0 ≦ c ≦ 3.0; - d represents a number such that 1.0 ≦ d ≦ 11.0; - e represents a number such that 0 < e ≦ 3.0; - M is an alkali metal selected from Na, K, Rb, Cs, and Fr) A method for preparing a solid sulfide material (A), comprising: Step (i) Formula (II): M a1 Li b1 P c1 S d1 X e1 (II) (wherein: - M is an alkali metal selected from Na, K, Rb, Cs, and Fr; - X represents at least one halogen element; - a1, b1, c1, d1, and e1 are real numbers; - a1 represents a number such that 0 < a1 ≦ 9 and a < a1; - b1 represents a number such that 0 ≦ b1 ≦ 6.0 and b1 < b; - 2.0 ≦ a1 + b1 ≦ 9; - c1 represents a number such that 1.0 ≦ c1 ≦ 3.0; - d1 represents a number such that 1.0 ≦ d1 ≦ 11.0; - e1 represents a number such that 0 < e1 ≦ 3.0) starting material (B); Stirring a mixture (M1) containing at least one lithium compound LiY (where Y is a counter anion) and a solvent (S) to promote the reaction between the starting material (B) that produces the solid sulfide material (A) and at least one metal compound MY and the lithium compound LiY; (ii) Obtaining a mixture (M2) containing the solid sulfide material (A), the metal compound MY, optionally unreacted lithium compound, and the solvent (S); (iii) Recovering the solid sulfide material (A) from the mixture (M2); (iv) Optionally, subjecting the solid sulfide material (A) recovered in step (iii) to heat treatment relates to a method comprising the above steps.

[0018] Without being bound by any theory, the method comprises reacting at least one lithium compound LiY with a compound of formula M a1 Li b1 P c1 S d1 X e1 It is believed that this is a cation exchange between (II) and the starting material (B).

[0019] Thus, the overall reaction that may occur during the process is: M a1 Li b1 P c1 S d1 X e1 (II) + αLiY → M a Li b P c S d X e (I) + αMY wherein M, X, Y, a1, a, b1, b, c1, c, d1, d, e1 and e are as previously defined; a = (a1-α) and b = (b1+α) and α≦a1) It can be expressed as:

[0020] It is believed that the most labile Na+ sites are replaced by Li+ during the process according to the invention, while the less labile Na+ sites preserve the structural morphology of the starting material. It is also believed that since the Li+ ionic radius is smaller than the Na+ ionic radius, improved mobility, and therefore improved ionic conductivity, is observed for the resulting solid sulfide material (A).

[0021] M is an alkali metal selected from Na, K, Rb, Cs and Fr. Preferably, M is Na. X is selected from Br, Cl, I and mixtures thereof. Preferably, X is selected from Br, Cl and mixtures thereof, more preferably, X is Cl. In some embodiments, M is Na and X is Cl; in some other embodiments, M is Na and X is Br; and in still some other embodiments, M is Na and X is Cl and Br. When X is Cl and Br, the molar ratio Cl / Br is generally in the range of 0.01 to 100.

[0022] In the process according to the invention, the starting material (B) generally has the following formula (II): M a1 Li b1 P c1 S d1 X e1 (II) (wherein M, X, a1, b1, c1, d1 and e1 are as previously defined). The solid sulfide material (A) prepared by the method according to the invention has the formula (I) M a Li b P c S d X e (I) (wherein M, X, a, b, c, d and e are as previously defined). It is of the following.

[0023] Moreover, the formula M a1 Li b1 P c1 S d1 X e1 The starting material (B) for (II) can be prepared by conventional methods described in the patent and non-patent literature.

[0024] In some embodiments, the starting material (B) is a crystalline solid sulfide containing Na, P, S, and optionally Li, where S 2- Replaced by X - is Na +When there are vacancies and / or Li, Li + A strategy for obtaining vacancies.

[0025] Thus, in some embodiments, the starting material (B) is of formula (IIa) Na 7-x-y Li x PS 6-y X y (IIa) (where 0 ≦ x < 7 - y and 0 < y ≦ 3), and the solid sulfide material (A) prepared by the method according to the invention is of formula (Ia) Na 7-x1-y Li x1 PS 6-y X y (Ia) (where 0 < x1 < 7 - y, x1 > x and 0 < y ≦ 3; X represents at least one halogen element) is of this kind.

[0026] For the solid sulfide (B) of formula (IIa) and the solid sulfide material (A) of formula (Ia), X is selected from Br, Cl, I and mixtures thereof. Preferably X is selected from Br, Cl and mixtures thereof, and more preferably X is Cl. When X is Cl and Br, the molar ratio Cl / Br is generally in the range of 0.01 - 100.

[0027] The solid sulfide (B) of formula (IIa) can be prepared by any method well known to those skilled in the art. Sodium sulfide (Na2S), lithium sulfide (Li2S), phosphorus pentasulfide (P2S5), lithium halide (LiX) and sodium halide (NaX) are generally used as raw materials in a convenient stoichiometry to form the desired sulfide composition.

[0028] For illustrative purposes, Na 7-x-y Li x PS 6-y X y can be prepared using the following stoichiometry: (7 - x - 2y)Na2S; (x)Li2S; 1P2S5; 2yNaX.

[0029] NaX is generally selected from NaCl, NaBr, NaI and mixtures thereof. LiX is generally selected from LiCl, LiBr, LiI and mixtures thereof. Commercially available raw materials can be used. However, those having a high degree of purity are preferred. The raw materials are generally in powder form.

[0030] In some other embodiments, the starting material (B) is a binary Na2S-P2S5-based glass-ceramic solid sulfide compound containing Na, P, S and optionally Li, optionally a ternary Na2S-Li2S-P2S5 glassy material, wherein the inorganic salts NaX and optionally LiX are added to increase the sodium ion concentration and optionally the lithium ion concentration.

[0031] Thus, in some embodiments, the starting material (B) has the formula (IIGa) (1-p)[7 / 2[(1-q)Na2S·qLi2S]·1 / 2P2S5]·p[(1-r)NaX·rLiX] (IIGa) (where 0 < p ≤ 0.5, 0 ≤ q < 1 and 0 ≤ r < 1, and X represents at least one halogen element) is a glass-ceramic.

[0032] In particular, when q = r = 0, the starting material (B) has the formula (IIGa') (1-p)Na7PS6·pNaX (IIGa') (where 0 < p ≤ 0.5 and X represents at least one halogen element) is a glass-ceramic.

[0033] Even more particularly, when q = r = 0 and p = 0.5, the starting material (B) has the formula (IIGa'') Na8PS6X (IIGa'') (where X represents at least one halogen element) is a glass-ceramic.

[0034] In some embodiments, the starting material (B) is of formula (IIGb) (1 - p)[4[(1 - q)Na2S·qLi2S]·1P2S5]·p[(1 - r)NaX·rLiX] (IIGb) (where 0 < p ≤ 0.5, 0 ≤ q < 1 and 0 ≤ r < 1, and X represents at least one halogen element) is a glass ceramic.

[0035] In particular, when q = r = 0, the starting material (B) is of formula (IIGb') (1 - p)Na8P2S9·pNaX (IIGb') (where 0 < p ≤ 0.5, and X represents at least one halogen element) is a glass ceramic.

[0036] Even more particularly, when q = r = 0 and p = 0.5, the starting material (B) is of formula (IIGb'') Na9P2S9X (IIGb'') (where X represents at least one halogen element) is a glass ceramic.

[0037] In some other embodiments, the starting material (B) is of formula (IIGc) (1 - p)[3 / 2[(1 - q)Na2S·qLi2S]·1 / 2P2S5]·p[(1 - r)NaX·rLiX] (IIGc) (where 0 < p ≤ 0.5, 0 ≤ q < 1 and 0 ≤ r < 1, and X represents at least one halogen element) is a glass ceramic.

[0038] In particular, when q = r = 0, the starting material (B) is of formula (IIGc') (1 - p)Na6P2S8·pNaX (IIGc') (where 0 < p ≤ 0.5, and X represents at least one halogen element) is a glass ceramic.

[0039] More particularly, when q = r = 0 and p = 0.5, the starting material (B) is of the formula (IIGc'') Na7P2S8X (IIGc'') (wherein X represents at least one halogen element) is a glass-ceramic.

[0040] Even more particularly, when q = r = 0 and p = 2 / 3, the starting material (B) is of the formula (IIGc''') Na4PS4X (IIGc''') (wherein X represents at least one halogen element) is a glass-ceramic.

[0041] In some further embodiments, the starting material (B) is of the formula (IIGd) (1 - p)[7 / 2[(1 - q)Na2S·qLi2S]·3 / 2P2S5]·p[(1 - r)NaX·rLiX] (IIGd) (where 0 < p ≤ 0.5, 0 ≤ q < 1 and 0 ≤ r < 1, and X represents at least one halogen element) is a glass-ceramic.

[0042] Particularly, when q = r = 0, the starting material (B) is of the formula (IIGd') (1 - p)Na7P3S 11 ·pNaX (IIGd') (where 0 < p ≤ 0.5, and X represents at least one halogen element) is a glass-ceramic.

[0043] More particularly, when q = r = 0 and p = 0.5, the starting material (B) is of the formula (IIGd'') Na8P3S 11 X (IIGd'') (wherein X represents at least one halogen element) is a glass-ceramic.

[0044] In some other embodiments, the starting material (B) is of the formula (IIGe) (1 - p)[1[(1 - q)Na2S·qLi2S]·1P2S5]·p[(1 - r)NaX·rLiX] (IIGe) (where 0 < p ≤ 0.5, 0 ≤ q < 1, and 0 ≤ r < 1, and X represents at least one halogen element) is a glass ceramic.

[0045] In particular, when q = r = 0, the starting material (B) has the formula (IIGe’) (1 - p)Na2P2S6·pNaX (IIGe’) (where 0 < p ≤ 0.5, and X represents at least one halogen element) is a glass ceramic.

[0046] Even more particularly, when q = r = 0 and p = 0.5, the starting material (B) has the formula (IIGe’’) Na3P2S6X (IIGe’’) (where X represents at least one halogen element) is a glass ceramic.

[0047] The glass ceramics of formulas (IIGa) - (IIGe), (IIGa’) - (IIGe’), (IIGa’’) - (IIGe’’), and (IIGc’’’) as described above can be prepared by any method well known to those skilled in the art. Na2S, Li2S, P2S5, NaX, and LiX are used as raw materials in stoichiometric amounts that are convenient for forming the desired composition. NaX is generally selected from NaCl, NaBr, NaI, and mixtures thereof. LiX is generally selected from LiCl, LiBr, LiI, and mixtures thereof. Commercially available raw materials can be used. However, those having a high degree of purity are preferred. The raw materials are generally in powder form.

[0048] For illustrative purposes only, the solid sulfide compounds of formula (IIa), (IIGa)-(IIGe), (IIGa')-(IIGe'), (IIGa'')-(IIGe'') and (IIGc''') can be prepared by well-known mechanochemical techniques, where the reaction can be induced by mechanical treatment or mechanical milling.

[0049] The mechanical milling reaction can be carried out using various types of conventional mechanical milling equipment, such as a planetary ball mill.

[0050] The rotation speed and rotation time of the mechanical milling are not particularly limited, but the higher the rotation speed, the faster the production rate of solid sulfides, and the longer the rotation time, the higher the conversion rate of the starting material to the desired sulfides. The mechanical treatment can be carried out for 1 to 130 hours.

[0051] The mechanical treatment can be carried out in the presence of a liquid (e.g. wet ball milling). A suitable liquid is generally a liquid hydrocarbon. The liquid hydrocarbon is often selected in the group consisting of aliphatic, cycloaliphatic, aromatic hydrocarbons and mixtures thereof. An aliphatic hydrocarbon is, for example, hexane, heptane, octane or nonane. An alicyclic hydrocarbon is, for example, cyclohexane, cyclopentane or cycloheptane. An aromatic hydrocarbon is, for example, benzene, toluene, ethylbenzene, xylene or liquid naphthenes. A convenient liquid hydrocarbon that can be used is xylene.

[0052] The mechanical treatment can be carried out under an inert atmosphere such as argon, nitrogen or mixtures thereof.

[0053] Generally, the mechanical treatment is carried out at room temperature (about 25° C.), but may also be carried out at higher temperatures.

[0054] After the mechanical treatment, the mixture obtained is generally calcined at a temperature ranging from 150° C. to 600° C. Calcination is generally carried out under an inert atmosphere, for example under an atmosphere of N2 or Ar or H2S. The duration of the calcination step is generally from 1 to 12 hours. Calcination can be carried out in a rotary oven.

[0055] After cooling, the solid sulfide can be recovered as granules, which can be sieved or ground to reach the desired particle size.

[0056] Calcination is generally carried out with a mixture that has been previously dried. This can be done by using already dried starting materials or by drying the mixture. When wet ball milling is used, drying can also be easily and conveniently carried out by evaporation of the liquid hydrocarbon. The evaporation of the liquid hydrocarbon is preferably carried out at a temperature between 100° C. and 150° C. The evaporation can be carried out under vacuum. The duration of the evaporation is generally between 1 hour and 20 hours.

[0057] The solid sulfide (B) of formula (IIa) can also be prepared by a solution process, for example as described in Journal of Power Sources 293 (2015) 941-945.

[0058] Sulfide glasses can be prepared by well-known mechanochemical techniques, where the reaction can be induced by mechanical treatment or mechanical milling. For example, such techniques are described in Solid State Ionics 270 (2015) 6-9 for the synthesis of Na3PS4-NaI glass ceramics.

[0059] Glass ceramics can also be prepared by solution processes, for example as described in Journal of Alloys and Compounds 798 (2019) 235-242, or by suspension processes, for example as described in Nature Reviews Chemistry, volume 3, pages 189-198 (2019).

[0060] The present invention relates to a new method for the preparation of solid sulfide materials with improved ionic conductivity.

[0061] As already mentioned, the overall reaction taking place during the process is: M a1 Li b1 P c1 S d1 X e1 (II) + αLiY → M a Li b P c S d X e (I) + αMY wherein M, X, Y, a1, a, b1, b, c1, c, d1, d, e1 and e are as previously defined; a = (a1-α) and b = (b1+α) and α≦a1) It can be expressed as:

[0062] The lithium compound LiY is generally selected from the list consisting of lithium triflate, lithium 4,5-dicyano-2-(trifluoromethyl)imidazole, lithium hexafluorophosphate, lithium bis(oxalato)borate, lithium bis(fluorosulfonyl)amide (LiFSA), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium acetate, lithium carbonate, lithium citrate, lithium nitrate, lithium chloride, lithium bromide, lithium oxalate, lithium iodide, lithium fluoride, lithium methyl carbonate, lithium ethyl carbonate, lithium methoxide and mixtures thereof. The Y counter anion is then independently selected from triflate, 4,5-dicyano-2-(trifluoromethyl)imidazolate, hexafluorophosphate, bis(oxalato)borate, bis(fluorosulfonyl)amide anion, bis(fluorosulfonyl)imide anion, bis(trifluoromethanesulfonyl)imide anion, acetate, carbonate, citrate, nitrate, chloride, bromide, iodide, fluoride, methylcarbonate, ethylcarbonate, methoxide, and mixtures thereof.

[0063] In some embodiments, the lithium compound LiY is lithium bis(fluorosulfonyl)amide (LiFSA). In some other embodiments, the lithium compound LiY is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

[0064] In some other embodiments, the lithium compound LiY is lithium chloride, lithium bromide, or a mixture thereof. In yet some other embodiments, the lithium compound LiY is lithium nitrate.

[0065] Generally, the starting material (B) and the lithium compound LiY are in powder form. Before use, the powders can be ground, for example using a zirconium mortar and pestle, or a planetary ball mill, or similar milling tool to obtain the desired particle size.

[0066] In general, the molar ratio LiY / B of the starting material (B) to the lithium compound LiY in the mixture (M1) is in the range of 1-20, and LiY / B is in the range of 2-7 in many cases.

[0067] The solvent (S) is generally selected from the list consisting of acetonitrile, adiponitrile, glutaronitrile, acetone, ethyl acetate, ethyl propionate, diethyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethylene carbonate, propylene carbonate, vinylene carbonate, DMF, NMP, DMSO, tetra(ethylene glycol) dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran and mixtures thereof.

[0068] In some embodiments, the solvent (S) is acetonitrile. In some other embodiments, the solvent (S) is ethylene carbonate. In some other embodiments, the solvent (S) is propylene carbonate. In yet some other embodiments, the solvent (S) is dimethyl carbonate.

[0069] Generally, the solvent (S) is anhydrous, which means that the solvent (S) contains less than 0.1% by weight, often less than 0.01% by weight, and sometimes less than 0.001% by weight of water.

[0070] In some embodiments, the lithium compound LiY is lithium bis(fluorosulfonyl)amide (LiFSA) and the solvent (S) is acetonitrile.

[0071] In some other embodiments, the lithium compound LiY is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and the solvent (S) is acetonitrile.

[0072] In yet some other embodiments, the lithium compound LiY is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and the solvent (S) is propylene carbonate.

[0073] In general, the weight ratio S / (B+LiY) of the weight of the lithium compound LiY and the starting material (B) to the weight of the solvent (S) is in the range of 1-50, often 2-25, and sometimes 5-10.

[0074] The components (A), (B), LiY and MY contained in the mixtures (M1) and (M2) may have different solubility behaviors in the solvent (S).

[0075] In some embodiments, the lithium compound LiY is partially solubilized in the solvent (S). By partially solubilized in the solvent (S), it is meant that at least 1% by weight and up to 99% by weight of the lithium compound LiY is solubilized in the solvent (S).

[0076] In some other embodiments, the lithium compound LiY is completely solubilized in the solvent (S).

[0077] In some embodiments, the metal compound MY is partially solubilized in the solvent (S). By partially solubilized in the solvent (S), it is meant that at least 1% by weight and up to 99% by weight of the metal compound is solubilized in the solvent (S).

[0078] In some other embodiments, the metal compound MY is completely solubilized in the solvent (S).

[0079] In some embodiments, the lithium compound LiY and the metal compound MY are partially solubilized in the solvent (S).

[0080] In some other embodiments, the lithium compound LiY is partially solubilized in the solvent (S) and the metal compound MY is completely solubilized in the solvent (S).

[0081] In yet some other embodiments, the lithium compound LiY and the metal compound MY are completely solubilized in the solvent (S).

[0082] The starting material (B) is generally not solubilized in the solvent (S). In many cases, the starting material (B) is suspended in the solvent (S). In some embodiments, the starting material (B) is swollen by the solvent (S).

[0083] In some embodiments, the starting material (B) is suspended in a solvent (S) while the lithium compound LiY is partially solubilized.

[0084] In some embodiments, the starting material (B) is suspended in the solvent (S) while the lithium compound LiY is completely solubilized.

[0085] The solid material (A) is generally not solubilized in the solvent (S). In many cases, the solid material (A) is suspended in the solvent (S). In some embodiments, the solid material (A) is swollen by the solvent (S).

[0086] In some embodiments, the solid material (A) is suspended in the solvent (S) while the lithium compound LiY and the metal compound MY are partially solubilized.

[0087] In some embodiments, the solid material (A) is suspended in the solvent (S) while the lithium compound LiY and the metal compound MY are completely solubilized.

[0088] In some embodiments, the starting material (B) and the solid material (A) are suspended in a solvent (S) while the lithium compound LiY and the metal compound MY are partially solubilized therein.

[0089] In some other embodiments, the starting material (B) and the solid material (A) are suspended in the solvent (S), while the lithium compound LiY and the metal compound MY are completely solubilized.

[0090] In yet some other embodiments, the starting material (B) and the solid material (A) are suspended in a solvent (S) while the lithium compound LiY and the metal compound MY are at least partially solubilized therein, whereby at least partially solubilized means that LiY and MY can be completely solubilized in the solvent (S), either simultaneously or not.

[0091] Generally, the starting material (B) and the lithium compound LiY are in powder form. Before use, the powders can be ground, for example using a zirconium mortar and pestle, or a planetary ball mill, or similar milling tool to obtain the desired particle size.

[0092] In some embodiments, the lithium compound LiY is partially or completely solubilized in the solvent (S) before the powder of the starting material (B) is added to form the mixture (M1).

[0093] In some other embodiments, the powder of the lithium compound LiY and the powder of the starting material (B) are added simultaneously or sequentially to the solvent (S) to form the mixture (M1).

[0094] Step (i) of the method according to the invention consists in stirring a mixture (M1) comprising a starting material (B), at least one lithium compound LiY, where Y is a counter anion, and a solvent (S) in order to promote the reaction of the starting material (B) with the lithium compound LiY to produce a solid sulfide material (A) and at least one metal compound MY.

[0095] The stirring of the mixture (M1) is generally carried out by any means known to those skilled in the art.

[0096] Generally, stirring is carried out at a temperature in the range of 15° C. to 70° C. In many cases, stirring is carried out at a temperature in the range of 15° C. to 40° C. Typically, stirring is carried out at a temperature in the range of 20° C. to 30° C.

[0097] The reaction of the starting material (B) with the lithium compound LiY is sometimes carried out until complete reaction of the starting material (B) to produce the solid sulfide material (A).

[0098] The mixture (M2) obtained in step (ii) comprises the solid sulfide material (A), the metal compound MY, optionally an unreacted lithium compound LiY and the solvent (S).

[0099] In some embodiments, in mixture (M2), the solid sulfide material (A) is suspended in the solvent (S), while the metal compound MY and, optionally, the unreacted lithium compound LiY, if present, are partially solubilized in the solvent (S).

[0100] In some other embodiments, in mixture (M2), the solid sulfide material (A) is suspended in the solvent (S), while the metal compound MY and, optionally, the unreacted lithium compound LiY, if present, are completely solubilized in the solvent (S).

[0101] In yet some other embodiments, in mixture (M2), the solid sulfide material (A) is suspended in solvent (S), while the metal compound MY and, optionally, the unreacted lithium compound LiY, if present, are at least partially solubilized in solvent (S). By at least partially solubilized, it is meant that MY and, if present, LiY are completely solubilized in solvent (S), either simultaneously or not.

[0102] In step (iii), the solid sulfide material (A) is recovered from the mixture (M2). The recovery can be carried out by centrifugation of the mixture (M2) to precipitate the suspended solid sulfide material (A), followed by removal of the supernatant. The obtained solid sulfide material (A) can then be suspended in fresh solvent (S), for example under stirring, and recovered by a new cycle of centrifugation / removal of the supernatant. Several cycles may be required to remove the metal compound MY and the unreacted lithium compound LiY.

[0103] In some embodiments, the solid sulfide material (A) can be recovered by a single filtration of the mixture (M2), optionally followed by a rinse with fresh solvent (S) to eliminate the metal compounds MY and the unreacted lithium compounds LiY.

[0104] In some embodiments, the recovered solid sulfide material (A) is subjected to several cycles comprising steps i) to iii).

[0105] The solid sulfide material (A) recovered in step iii) is optionally further subjected to a heat treatment in step iv), which is generally carried out at a temperature in the range of 50°C to 550°C.

[0106] The heat treatment of step iv) may comprise the evaporation of residual solvent (S) in the solid sulfide material (A) recovered in step (iii). The evaporation of the residual solvent (S) is generally carried out at a temperature ranging from 50° C. to 150° C. The evaporation may be carried out under vacuum. The duration of the evaporation is generally from 1 to 20 hours, more particularly from 2 to 20 hours or from 3 to 7 hours. At the end of the evaporation, the solid sulfide material (A) may contain some residual solvent (S). The amount of residual solvent is generally such that the carbon content in the solid sulfide material (A) is less than 2.0% by weight. The carbon content may be from 0.01 to 1.0% by weight.

[0107] The heat treatment of step iv) may also include a heat treatment at a temperature above 150°C and up to 550°C.

[0108] In some embodiments, the heat treatment includes evaporation of residual solvent (S) at temperatures ranging from 50°C to 150°C as well as heat treatment at temperatures above 150°C and up to 550°C.

[0109] In some other embodiments, the heat treatment consists of evaporating the remaining solvent (S) at a temperature ranging from 50°C to 150°C.

[0110] Generally, the solid sulfide material (A) is recovered in the form of a powder, which can be ground using, for example, a zirconium mortar and pestle, or a planetary ball mill, or similar milling tool to obtain the desired particle size.

[0111] The present invention also relates to a solid sulfide material (A) as defined previously, prepared by the process according to the invention.

[0112] The present invention also relates to the use of such solid sulfide materials as solid electrolytes.

[0113] The present invention also relates to an electrochemical device comprising a solid electrolyte comprising at least a solid sulfide material (A) as previously defined, prepared by the method according to the invention.

[0114] Preferably, in an electrochemical device, particularly a rechargeable electrochemical device, the solid electrolyte is a solid structural component for the electrochemical device selected from the group consisting of the cathode, the anode and the separator.

[0115] Preferably herein, the solid electrolyte is a component of a solid structure for an electrochemical device, where the solid structure is selected from the group consisting of a cathode, an anode and a separator. Thus, the solid sulfide material (A) prepared by the method according to the present invention can be used alone or in combination with additional components for producing a solid structure for an electrochemical device, such as a cathode, an anode or a separator.

[0116] The electrode that develops a net negative charge during discharge is called the anode, and the electrode that develops a net positive charge during discharge is called the cathode. A separator electronically separates the cathode and anode from each other in an electrochemical device.

[0117] Suitable electrochemically active cathode materials and suitable electrochemically active anode materials are well known in the art. In the electrochemical device according to the present invention, the anode preferably comprises graphite carbon, metallic lithium, Si, silicon compounds such as SiO x and lithium-containing metal alloys containing an anode active material such as silicon compounds, lithium titanate such as Li4Ti5O 12 or Sn.

[0118] In the electrochemical device according to the present invention, the cathode preferably comprises a metal chalcogenide of the formula LiMeQ2 (wherein Me is at least one metal selected from transition metals such as Co, Ni, Fe, Mn, Cr and V, and Q is a chalcogen such as O or S). Among these, it is preferable to use a lithium-based composite metal oxide of the formula LiMeO2 (wherein Me is the same as defined above). Preferred examples thereof include LiCoO2, LiNiO2, LiNixCo 1-x O2 (0 < x < 1), and spinel-structured LiMn2O4 and LiMn 1.5 Ni 0.5 O4. Another preferred example thereof includes a lithium-nickel-manganese-cobalt-based metal oxide of the formula LiNi x Mn y Co z O2 (x + y + z = 1, referred to as NMC), for example, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2 and a lithium-nickel-cobalt-aluminum-based metal oxide of the formula LiNi x Co y Al z O2 (x + y + z = 1, referred to as NCA), for example, LiNi 0.8 Co 0.15 Al 0.05 O2. The cathode may include a lithiated or partially lithiated transition metal oxyanion-based material such as LiFePO4.

[0119] For example, the electrochemical device has a cylindrical-like shape or a prismatic shape.The electrochemical device can include a housing, which can be made of steel or aluminum or a multi-layer film polymer / metal foil.

[0120] A further aspect of the present invention refers to a battery, more preferably an alkali metal battery, in particular a lithium battery comprising at least one, e.g. two or more, inventive electrochemical devices. The electrochemical devices can be combined with one another, e.g. in series or parallel connection, in an inventive alkali metal battery.

[0121] The present invention also relates to a battery, preferably a lithium battery, comprising at least a solid sulfide material (A) obtainable by the process according to the invention.

[0122] The battery in which the solid sulfide material (A) obtained by the process according to the invention is used can be a lithium ion battery or a lithium metal battery.

[0123] Typically, a lithium solid-state battery includes a positive electrode active material layer containing a positive electrode active material, a negative electrode active material layer containing a negative electrode active material, and a solid electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer includes a solid electrolyte as defined above.

[0124] The cathode of an all-solid-state electrochemical device typically comprises a solid electrolyte in addition to a cathode active material, and similarly, the anode of an all-solid-state electrochemical device typically comprises a solid electrolyte in addition to an anode active material.

[0125] The morphology of the solid-state structure for an electrochemical device, in particular for an all-solid-state lithium battery, depends in particular on the morphology of the electrochemical device itself to be produced. The present invention further provides a solid-state structure for an electrochemical device, wherein the solid-state structure is selected from the group consisting of a cathode, an anode and a separator, wherein the solid-state structure for an electrochemical device comprises a solid sulfide material (A) obtainable by the method according to the present invention.

[0126] Multiple electrochemical cells can be combined into an all-solid-state battery, having both solid electrodes and a solid electrolyte.

[0127] The present invention also relates to an electrode comprising at least a solid sulfide material (A) obtainable by the process according to the invention.

[0128] The solid sulfide material (A) obtained by the method according to the invention disclosed above can be used for the preparation of an electrode. The electrode can be a positive or negative electrode.

[0129] The electrodes typically comprise at least: - Metal substrate; a layer of composition (C) in contact with a metal substrate, said composition (C) comprising: (i) a solid sulfide material (A) obtainable by the process according to the invention; (ii) at least one electroactive compound (EAC); (iii) optionally at least one material conducting Li-ions other than the solid sulfide material (A) obtainable by the method according to the invention; (iv) optionally, at least one electrically conductive material (ECM); (v) optionally a lithium salt (LIS); (vi) optionally at least one polymeric binder material (P) A layer of a composition (C) comprising Includes.

[0130] Electroactive compound (EAC) refers to a compound capable of incorporating or inserting and releasing lithium ions into its structure during the charging and discharging phases of an electrochemical device. The EAC may be a compound capable of inserting and de-inserting lithium ions into its structure. For the positive electrode, the EAC may be of the formula LiMeQ2, where: - Me is at least one metal selected from the group consisting of Co, Ni, Fe, Mn, Cr, Al and V; - Q is a chalcogen such as O or S) can be a composite metal chalcogenide of

[0131] EAC can more particularly be of the formula LiMeO2. Preferred examples of EAC include LiCoO2, LiNiO2, LiMnO2, LiNi x Co 1-x O2 (0 < x < 1), LiNi x Co y Mn z O2 (0 < x, y, z < 1 and x + y + z = 1), for example LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2, Li(Ni x Co y Al z )O2 (x + y + z = 1) and spinel structured LiMn2O4 and Li(Ni 0.5 Mn 1.5 )O4.

[0132] EAC can also be of the formula M1M2(JO4) f E 1-f (wherein: - M1 is lithium which can be partially replaced by another alkali metal representing less than 20% of M1; - M2 is a transition metal at a +2 oxidation level selected from Fe, Co, Mn, Ni or mixtures thereof which can be partially replaced by one or more additional metals representing less than 35% of the M2 metal at an oxidation level of +1 to +5 and including 0; - JO4 is any oxyanion where J is any of P, S, V, Si, Nb, Mo or combinations thereof; - E is a fluoride anion, hydroxide anion or chloride anion; - f is generally a mole fraction of the JO4 oxyanion included in 0.75 to 1) The electroactive material may be a lithiated or partially lithiated transition metal oxyanion based material.

[0133] M1M2(JO4) as defined above f E 1-f The electroactive material is preferably phosphate-based. It may exhibit an ordered structure or a modified olivine structure.

[0134] For the positive electrode, the EAC can also be sulfur or Li2S.

[0135] For the positive electrode, the EAC can also be a conversion type material such as FeS2 or FeF2 or FeF3.

[0136] For the negative electrode, the EAC may be selected from the group consisting of graphitic carbons capable of intercalating lithium. Further details on this type of EAC may be found in Carbon 2000, 38, 1031-1041. This type of EAC is typically present in the form of powders, flakes, fibers or spheres (e.g., mesocarbon microbeads).

[0137] EACs also include lithium metal; lithium alloy compositions (such as those described in U.S. Pat. No. 6,203,944 and WO 00 / 03444); generally, lithium alloys of the formula Li4Ti5O 12 Lithium titanates, represented by the formula Li (these compounds are generally considered "zero strain" insertion materials, which have a low level of physical expansion upon incorporation of mobile ions, i.e., Li+); lithium-silicon alloys, commonly known as lithium silicides with high Li / Si ratios, particularly those of the formula Li 4.4 Lithium silicide of formula Si; and Li 4.4 The EAC may be a lithium-germanium alloy, containing a crystalline phase of Ge. The EAC may also be a composite material based on silicon and / or silicon oxide-filled carbonaceous materials, especially graphitic carbon / silicon and graphite / silicon oxide, where the graphitic carbon is composed of one or several carbons capable of intercalating lithium.

[0138] The ECM is typically selected from the group consisting of conductive carbonaceous materials and metal powders or fibers. The conductive carbonaceous materials may be selected from the group consisting of, for example, carbon black, carbon nanotubes, graphite, graphene, and graphite fibers, and combinations thereof. Examples of carbon black include ketjen black and acetylene black. Metal powders or fibers include nickel and aluminum powders or fibers.

[0139] The lithium salt (LIS) may be selected from the group consisting of LiPF6, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, LiB(C2O4)2, LiAsF6, LiClO4, LiBF4, LiAlO4, LiNO3, LiCF3SO3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiC(SO2CF3)3, LiN(SO3CF3)2, LiC4F9SO3, LiCF3SO3, LiAlCl4, LiSbF6, LiF, LiBr, LiCl, LiOH and lithium 2-trifluoromethyl-4,5-dicyanoimidazole.

[0140] The function of the polymeric binder material (P) is to bind the components of the composition. The polymeric binder material is usually inert. It should preferably also be chemically stable and facilitate electronic and ionic transport. Polymeric binder materials are well known in the art. Non-limiting examples of polymeric binder materials include, inter alia, vinylidene fluoride (VDF)-based (co)polymers, styrene-butadiene rubber (SBR), styrene-ethylene-butylene-styrene (SEBS), carboxymethylcellulose (CMC), polyamideimide (PAI), poly(tetrafluoroethylene) (PTFE) and poly(acrylonitrile) (PAN) (co)polymers.

[0141] The proportion of the solid sulfide material (A) obtained by the method according to the invention in the composition can be 0.1% to 80% by weight, based on the total weight of the composition. In particular, this proportion can be 1.0% to 60% by weight, more particularly 5% to 30% by weight. The thickness of the electrode is not particularly limited and should be adjusted with respect to the energy and power required in the application. For example, the thickness of the electrode can be 0.01 mm to 1,000 mm.

[0142] The present invention also relates to a separator comprising at least a solid sulfide material (A) obtainable by the process according to the invention.

[0143] The solid sulfide material (A) obtained by the process according to the invention can also be used for the preparation of a separator. A separator is an ion-permeable membrane placed between the anode and the cathode of a battery. Its function is to allow the passage of lithium ions while blocking electrons and ensuring physical separation between the electrodes.

[0144] The separator of the present invention typically comprises at least: - a solid sulfide material (A) obtainable by the process according to the invention; - optionally at least one polymeric binding material (P); - optionally at least one metal salt, in particular a lithium salt; - optionally at least one plasticizer Includes.

[0145] The electrodes and separators can be prepared using methods well known to those skilled in the art, which typically involve mixing the components in a suitable solvent and removing the solvent. For example, the electrodes can be prepared using the following steps: - applying a slurry comprising the components of the composition and at least one solvent onto a metal substrate; - The solvent is removed It can be prepared by a method comprising:

[0146] Common techniques known to those skilled in the art are: coating and calendaring, dry and wet extrusion, 3D printing, sintering of porous foams followed by impregnation. Common preparation techniques of electrodes and of separators are provided in Journal of Power Sources, 2018 382, ​​160-175.

[0147] Electrochemical devices, particularly batteries such as the solid-state batteries described herein, can be used to manufacture or operate stationary applications such as automobiles, computers, personal digital assistants, cell phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOS, communication equipment or remote car locks, and energy storage devices for power plants.

[0148] Electrochemical devices, especially batteries such as the solid-state batteries described herein, can be used in, among others, motorized vehicles, bicycles driven by electric motors, robots, aircraft (e.g. unmanned aerial vehicles such as drones), ships or stationary energy storage. Mobile devices such as vehicles, for example automobiles, bicycles, aircraft, or water vehicles such as boats or ships, are preferred. Other examples of mobile devices are those that are portable, such as computers, especially laptops, telephones, or power tools, for example from the construction sector, especially drills, battery-powered screwdrivers or battery-powered nailers.

[0149] To the extent that the disclosures of any patents, patent applications, and publications incorporated herein by reference conflict with the statements of this application to the extent that any term may be unclear, this statement shall control. EXAMPLES

[0150] Characterization: Ionic conductivity can be measured on pressed (500 MPa) pellets by impedance spectroscopy.

[0151] The measurement of ionic conductivity is generally carried out on pressed pellets. Typically, pressed pellets are produced using uniaxial or isostatic pressure. When applying uniaxial pressure to form pellets, a pressure of more than 100 MPa, advantageously more than 300 MPa, is applied for a duration of at least 30 seconds. Measurements are typically carried out under uniaxial pressures of 2 MPa to 200 MPa.

[0152] The pellets are sandwiched between pre-dried carbon paper electrodes, used as current collectors, and then loaded into an airtight sample holder. AC impedance spectra are collected by using a Biologic VMP3 device. The samples are placed in a binder thermostat for impedance measurements at different temperatures. Each spectrum is acquired after 2 hours of stabilization at the target temperature. The temperature range varies from -20°C to 60°C in steps of 10°C. Impedance spectroscopy is acquired in PEIS mode (25 points per decade and an average of 50 measurements per frequency point) with an amplitude of 20 mV and a frequency range of 1 MHz to 1 kHz. Ionic conductivity values ​​are obtained by fitting the data to an equivalent circuit model using ZView software. The slope of the σT vs. 1 / T plot is calculated to fit equation 1: Equation 1:

number

[0153] The inventors have hereby surprisingly found that the solid sulfide material (A) prepared by the method according to the invention has an improved ionic conductivity when compared to solid sulfide materials having a similar composition but prepared by conventional methods such as high temperature solid-state synthesis or mechanochemical routes.

[0154] Manufacturing Example In an Ar-filled glove box, Li2S (Lorad Chemical), LiCl (Sigma-Aldrich), Na2S (Sigma-Aldrich), and P2S5 (Sigma-Aldrich) were weighed and mixed in stoichiometric proportions to prepare Li5.8 Na 0.2 8 g of the desired composition of PS5Cl was obtained. The mixture was then transferred into two 45 mL ZrO2 jars filled with 5 mm zirconia (YSZ) balls. The ball to powder ratio was fixed at 16.5. The jars were sealed, removed from the glove box, and placed in a Fritsch Planetary Micro Mill Pulverisette 7. The mixture was ball milled for 2 hours at 500 RPM rotation speed with a 15 minute break every 30 minutes of milling. The powder was collected in an Ar-filled glove box (<1 ppm H2O, <1 ppm O2). The resulting powder was transferred into a closed SiC crucible (Papyex) in a carbon paper box.

[0155] The crucible was heated to 500 °C in a tube furnace under N2 atmosphere at a heating rate of 5 °C / min and kept at this temperature for 12 h. The sample was then cooled to room temperature. It was retrieved in an Ar-filled glove box and crushed in a mortar.

[0156] A lattice parameter of 9.86 Å in the presence of Li2S impurity at a 2 wt% level was identified for the argon germanite phase.

[0157] Example 1 A propylene carbonate electrolyte containing 2M LiTFSI was prepared by mixing the lithium salts and dissolving them at room temperature for 72 hours.

[0158] 500 mg of the preparation was stirred with 2 mL of electrolyte for 72 h and then filtered on a PVDF filter (45 μm). The powder and liquid were separated and collected, and the powder was dried under vacuum in a Buchi oven at 130° C. for 12 h.

[0159] The ionic conductivity at 30° C. was 1.2 mS / cm, associated with an activation energy of 0.42 eV.

[0160] Example 2 An acetonitrile electrolyte containing 2M LiTFSI was prepared by mixing the lithium salts and dissolving them at room temperature for 72 hours.

[0161] 500 mg of the preparation was stirred with 2 mL of electrolyte for 72 h and then filtered on a PVDF filter (45 μm). The powder and liquid were separated and collected, and the powder was dried under vacuum in a Buchi oven at 130° C. for 12 h.

[0162] The ionic conductivity at 30° C. was 2.47 mS / cm, associated with an activation energy of 0.41 eV.

[0163] Comparative Example 3 500 mg of the preparation was stirred with 2 mL of propylene carbonate for 72 h, then filtered on a PVDF filter (45 μm). The powder and liquid were separated and collected, and the powder was dried under vacuum in a Buchi oven at 130° C. for 12 h.

[0164] The ionic conductivity at 30° C. was 0.7 mS / cm, associated with an activation energy of 0.40 eV.

[0165] Comparative Example 4 500 mg of the preparation was stirred with 2 mL of acetonitrile for 72 h and then filtered on a PVDF filter (45 μm). The powder and liquid were separated and collected, and the powder was dried under vacuum in a Buchi oven at 130° C. for 12 h.

[0166] The ionic conductivity at 30° C. was 1.1 mS / cm, associated with an activation energy of 0.41 eV.

[0167] Rather than pure propylene carbonate, according to the method of the present invention, propylene carbonate is reacted with propylene carbonate having the formula Li 5.8 Na 0.2It is clear that the treatment of the preparation of PS5Cl with the lithium compound LiTFSI improves the ionic conductivity of the resulting powder material. In fact, the ionic conductivity of the resulting powder obtained in Example 1 is 1.2 mS / cm, while that of the resulting powder obtained in Comparative Example 3 is only 0.7 mS / cm.

[0168] Similarly, rather than in pure acetonitrile, it is also possible to prepare, according to the method of the present invention, a compound of the formula Li in acetonitrile. 5.8 Na 0.2 It is clear that the treatment of the preparation of PS5Cl with the lithium compound LiTFSI improves the ionic conductivity of the resulting powder material. In fact, the ionic conductivity of the resulting powder obtained in Example 3 is 2.47 mS / cm, while the ionic conductivity of the resulting powder obtained in Comparative Example 4 is only 1.1 mS / cm.

Claims

1. Formula (I): M ａ Li ｂ P ｃ S ｄ X ｅ (I) (In the formula: X represents at least one halogen element; a, b, c, d and e are real numbers; a represents a number such that 0≦a<9; b represents a number such that 0<b≦9; 2.0≦a+b≦9; - c represents a number such that 1.0≦c≦3.0; - d represents a number such that 1.0≦d≦11.0; - e represents a number such that 0<e≦3.0; M is an alkali metal selected from Na, K, Rb, Cs and Fr. A method for preparing a solid sulfide material (A) of the present invention, comprising the steps of: process (i) Formula (II): M ａ１ Li ｂ１ P ｃ１ S ｄ１ X ｅ１ (II) (In the formula: M is an alkali metal selected from Na, K, Rb, Cs and Fr; X represents at least one halogen element; a1, b1, c1, d1 and e1 are real numbers; a1 represents a number such that 0<a1≦9 and a<a1; b1 represents a number such as 0≦b1≦6.0 and b1<b; - 2.0≦a1+b1≦9; c1 represents a number such that 1.0≦c1≦3.0; - d1 represents a number such that 1.0≦d1≦11.0; - e1 represents a number such as 0<e1≦3.0) Starting material (B); agitating a mixture (M1) comprising at least one lithium compound LiY, where Y is a counter anion, and a solvent (S) to promote a reaction of the lithium compound LiY with the starting material (B) to produce a solid sulfide material (A) and at least one metal compound MY; (ii) obtaining a mixture (M2) comprising a solid sulfide material (A), a metal compound MY, optionally an unreacted lithium compound LiY, and a solvent (S); (iii) recovering the solid sulfide material (A) from the mixture (M2); (iv) optionally subjecting the solid sulfide material (A) recovered in step (iii) to a heat treatment. A method comprising:

2. The starting material (B) is a compound of formula (IIa) Na ７－ｘ－ｙ Li ｘ PS ６－ｙ X ｙ (IIa) wherein 0≦x<7−y and 0<y≦3, and the solid sulfide material (A) is of formula (Ia): Na ７－ｘ１－ｙ Li ｘ１ PS ６－ｙ X ｙ (Ia) (Wherein, 0<x1<7-y, x1>x, and 0<y≦3) The method of claim 1 ,

3. The starting material (B) is a compound of formula (IIGa) (1-b)l7bb2l(1-b)8b ２ ｳ・qLi ２ S･1 / 2P ２ ﳳ ５ ]・p[(1-rr)NaX・r:iX) (991a) (Wherein, 0<p≦0.50, 0≦q<1, and 0≦r<1; X represents at least one halogen element. The method of claim 1 , wherein the glass ceramic is

4. The starting material (B) is a compound of formula (IIGb) (1-p[4[(1-qo)8a ２ ｳ・qLi ２ 3)・10 ２ ﳳ ５ ]・p[(1-rr)ｮaX・r:iX ) (991b) (Wherein, 0<p≦0.50, 0≦q<1, and 0≦r<1; X represents at least one halogen element. The method of claim 1 , wherein the glass ceramic is

5. The starting material (B) is a compound of formula (IIGc) (1-1)l3b2l(1-1)8 ２ ｳ・qLi ２ S･1 / 2P ２ ﳳ ５ ]・p[(1-rr)ｮaX・r:iX) ]) (Wherein, 0<p≦0.50, 0≦q<1, and 0≦r<1; X represents at least one halogen element. The method of claim 1 , wherein the glass ceramic is

6. The starting material (B) is a compound of formula (IIGd) (1-b)l7bb2l(1-b)8b ２ ｳ・qLi ２ S]・3 / 2P ２ ﳳ ５ ]・pｻ(1mrr)X・rriX) (99od ); (Wherein, 0<p≦0.50, 0≦q<1, and 0≦r<1; X represents at least one halogen element. The method of claim 1 , wherein the glass ceramic is

7. The starting material (B) is a compound of formula (IIGe) (1-p)[[(1-q)Na ２ S・qLi ２ S]・P ２ S ５ ]・p[(1-r)NaX・rLiX] (IIGe); (Wherein, 0<p≦0.50, 0≦q<1, and 0≦r<1; X represents at least one halogen element. The method of claim 1 , wherein the glass ceramic is

8. 2. The method of claim 1, wherein the lithium compound LiY is selected from the list consisting of lithium triflate, lithium 4,5-dicyano-2-(trifluoromethyl)imidazole, lithium hexafluorophosphate, lithium bis(oxalato)borate, lithium bis(fluorosulfonyl)amide (LiFSA), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium acetate, lithium carbonate, lithium citrate, lithium nitrate, lithium chloride, lithium bromide, lithium oxalate, lithium iodide, lithium fluoride, lithium methyl carbonate, lithium ethyl carbonate, lithium methoxide, and mixtures thereof.

9. 2. The process of claim 1, wherein the solvent (S) is selected from the list consisting of acetonitrile, adiponitrile, glutaronitrile, acetone, ethyl acetate, ethyl propionate, diethyl ether, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate, ethylene carbonate, propylene carbonate, vinylene carbonate, DMF, NMP, DMSO, tetra(ethylene glycol) dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, and mixtures thereof.

10. 2. The method of claim 1, wherein the starting material (B) and the solid sulfide material (A) are suspended in the solvent (S) while the lithium compound LiY and the metal compound MY are at least partially solubilized in the solvent (S).

11. A solid sulfide material (A) obtainable by the method according to any one of claims 1 to 10.

12. 12. Use of the solid sulfide material (A) according to claim 11 as a solid electrolyte.

13. A solid electrolyte comprising at least the solid sulfide material (A) described in claim 11.

14. An electrochemical device comprising the solid electrolyte of claim 13.

15. at least: - Metal substrate; a composition (C) in contact with a metal substrate, said composition (C) comprising: (i) the solid sulfide material (A) according to claim 11; (ii) at least one electroactive compound (EAC); (iii) optionally at least one lithium ion-conducting material (LiCM) other than a solid sulfide material obtained by the method according to the invention; (iv) optionally at least one electrically conductive material (ECM); (v) optionally a lithium salt (LIS); and (vi) optionally at least one polymeric binder material (P) At least one layer made from a composition (C) comprising An electrode comprising:

16. at least: - a solid sulfide material (A) according to claim 11; optionally at least one polymeric binder material (P); optionally at least one metal salt, in particular a lithium salt; and optionally at least one plasticizer Contains separators.