Process for obtaining lithium sulfide powder and its use for preparing LPS compounds

Abstract

The present disclosure provides a d50 value of less than 10 μm, 2 The present disclosure relates to a process for obtaining a lithium sulfide powder (Li2S powder) having a specific surface area of ​​more than 0.035 cm3 / g, a total pore volume of more than 0.035 cm3 / g and a proportion of the total pore volume made up of pores with a diameter of less than 20 nm of more than 20%, comprising the steps of a) providing a lithium hydroxide powder (LiOH powder A) having a d50 value of less than 10 μm and exhibiting a residual water content of less than 5% by weight, and b) reacting such LiOH powder A with a sulfide reactant to obtain Li2S powder. The present disclosure also relates to the lithium sulfide powder obtained from such a process and to the use of such Li2S powder for preparing a solid compound of formula (I): LiaPSbXc, where - X represents at least one halogen element, - a represents a number between 3.0 and 6.0, - b represents a number between 3.5 and 5.0, and - c represents a number between 0 and 3.0.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application Publication No. 21315122.8 filed in Europe on July 7, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present disclosure provides a d 50 Value, 5m 2 / g, specific surface area of ​​0.035 cm 3 A process for obtaining a lithium sulfide powder (LiS powder) having a total pore volume of more than 10 μm / g and a proportion of the total pore volume made up of pores with a diameter of less than 20 nm of more than 20%, comprising: a) a pore size of less than 10 μm; 50 The present disclosure relates to a process comprising the steps of b) providing a powder of lithium hydroxide (LiOH powder A) having a value of 0.1 to 0.5 and exhibiting a residual water content of less than 5% by weight, and b) reacting such LiOH powder A with a sulfide reactant to obtain Li2S powder. Li a P.S. b X c (I) (In the formula, - X represents at least one halogen element; - a is a number between 3.0 and 6.0, - b is a number between 3.5 and 5.0, and - c represents a number between 0 and 3.0) The present invention also relates to the use of such Li2S powder for preparing a solid compound of the formula: [Background technology]

[0003] Lithium-ion batteries are widely used, especially as power sources for consumer electronics. In such secondary batteries, organic solvents are used as organic liquid electrolytes, and lithium ions migrate from one electrode to the other depending on whether the battery is being charged or discharged.

[0004] Since the solvents used as electrolytes are flammable, all-solid-state lithium-ion batteries that do not use organic solvents are very attractive. Such all-solid-state lithium-ion batteries are formed by solidifying the entire battery using a solid electrolyte that contains Li, P, S, and a halogen, for example.

[0005] One of the starting materials for preparing such solid electrolytes is lithium sulfide (Li2S). The technical characteristics of such starting materials (e.g. purity, particle size and porosity) are important to obtain high purity solid electrolytes. Various methods have been disclosed in the art for the production of Li2S.

[0006] For example, US Patent Application Publication No. 2020 / 165129A1 (Albemarle) relates to Li2S powders and their preparation, and such powders have an average particle size of 250-1,500 μm and a mean particle size of 1-100 μm. 2 The preparation process comprises: a) heating lithium hydroxide monohydrate having an average particle size in the range of 150-2,000 μm in a temperature controlled apparatus to a reaction temperature of 150° C.-450° C. in the absence of air and flowing an inert gas over or through the apparatus until the lithium hydroxide crystals formed contain less than 5% by weight of residual water; and b) overflowing or permeating the lithium hydroxide anhydrate formed in the first step with a sulfur source.

[0007] However, such Li2S powders have the disadvantage of having a high average particle size of more than 100 μm, which requires further processing before use, especially when such Li2S powders are used for preparing battery components.

[0008] US Patent Application Publication No. 2015 / 0246811 (Arkema France) discloses a method for preparing an alkali metal sulfide, comprising the steps of: reacting at least one oxygen-containing compound of said alkali metal sulfide with an oxygen-containing compound of formula (I) RS(=O) nThe process comprises at least one step a) of reaction of -Sx-R' with at least one sulfur-containing compound. Two embodiments are disclosed for carrying out said step a). The first embodiment is carried out at temperatures between 150°C and 500°C, preferably between 150°C and 400°C, preferably between 200°C and 350°C, in the presence of at least one catalyst, with the aim of increasing the rate of reaction. The second embodiment is carried out at temperatures preferably between 300°C and 800°C, preferably between 300°C and 600°C, optionally in the absence of a catalyst. In step a), it is preferred to add water or hydrogen can be used instead of water. In the examples, the preliminary steps are carried out at temperatures of 550°C and 250°C under nitrogen flow. The process is carried out by reacting a complex feedstock (RS(=O) n -Sx-R') and the need for the use of a catalyst or high reaction temperatures.

[0009] Ohsaki et al. (Powder Technology, 387, July 2021, 415-420) describe the synthesis of Li3PS4 solid electrolyte particles with size control in the submicron range using a liquid phase shaking method, starting with fine Li2S particles, which need to be processed through a wet grinding or dissolution precipitation process before being used to prepare Li3PS4 solid electrolyte particles.

[0010] US Patent Application Publication No. 2016 / 0104916 (Idemitsu Kosan Co., Ltd.) discloses a method for producing a solid electrolyte, which comprises contacting an alkali metal sulfide, one or more sulfur compounds and a halogen compound with each other in a solvent. The preparation of the alkali metal sulfide, in particular Li2S, is disclosed with reference to methods known from the prior art. For example, the reaction of lithium hydroxide with hydrogen sulfide in a hydrocarbon-based solvent at 70°C to 300°C is disclosed. Lithium sulfide can be modified with a solvent, including a polar solvent, thereby obtaining a large specific surface area. In Production Example 1, toluene is used. The particle size of the alkali metal sulfide used as a raw material is not limited, but the particle size may actually exceed 100 micrometers because the step of reducing the particle size is not always advantageous in terms of cost.

[0011] Anode materials and preparation methods thereof are also disclosed in US Patent Application Publication No. 2013 / 0295464 (Idemitsu Kosan Co., Ltd.). Hydrogen sulfide and alkali metal hydroxides can be used as raw materials. Preparation Example 1 discloses the reaction of lithium hydroxide with hydrogen sulfide in N-methyl-2-pyrrolidone (NMP) at 130°C. Summary of the Invention

[0012] Applicants have recognized that Li2S suffers from poor cycling stability, slow rate performance, and a high initial activation potential.

[0013] In addition, Applicants have recognized that commercially available Li2S is expensive and has a large particle size of over 10 μm, which further exacerbates its shortcomings as a battery component.

[0014] The Applicant was therefore faced with the problem of providing a new process for the manufacture of Li2S powder.

[0015] More specifically, Applicant was faced with the problem of providing a process for producing small sized Li2S particles that can remain uniformly dispersed.

[0016] The present invention provides a d 50 value (measured by laser diffraction in paraxylene), 5m 2 / g (measured by nitrogen gas adsorption using the Brunauer-Emmett-Teller (BET) method), with a specific surface area of ​​0.035 cm 3 1. A process for obtaining a lithium sulfide powder (LiS powder) having a total pore volume of more than 1000 μg / g (measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) and a proportion of the total pore volume consisting of pores with a diameter of less than 20 nm (measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) of more than 20%, a) d less than 10 μm 50 providing a powder of lithium hydroxide (LiOH powder A) having a value of 0.01% by weight and exhibiting a residual water content of less than 5% by weight; b) reacting such LiOH powder A with a sulfide reactant to obtain a Li2S powder and LiOH powder A includes: - d less than 10 μm 50 To obtain a powder of lithium hydroxide monohydrate (LiOH.HO) (LiOH powder C) with a d value of more than 10 μm, 50 grinding a powder of lithium hydroxide monohydrate (LiOH.HO) having a value of 0.05 to 0.5% by mass (LiOH powder B) and heating such LiOH powder C at a temperature below 180° C. to obtain LiOH powder A; or - heating a powder of lithium hydroxide monohydrate (LiOH.H2O) exhibiting a residual water content of more than 5% by weight at a temperature of less than 180°C to obtain a powder of lithium hydroxide exhibiting a residual water content of less than 5% by weight (LiOH powder D) and grinding such LiOH powder D to obtain LiOH powder A. The process relates to a process obtained by

[0017] The present invention provides a d 50 value (measured by laser diffraction in paraxylene), 5m 2 / g (measured by nitrogen gas adsorption using the Brunauer-Emmett-Teller (BET) method), with a specific surface area of ​​0.035 cm 3 The present invention also relates to a powder of lithium sulfide (LiS powder) having a total pore volume of more than 200 nm / g (as measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) and a percentage of the total pore volume made up of pores with a diameter of less than 20 nm (as measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) of more than 20%.

[0018] The present invention relates to a compound of formula (I): Li a P.S. b X c (I) (In the formula, X represents at least one halogen element; a represents a number between 3.0 and 6.0, b represents a number between 3.5 and 5.0; and (c represents a number between 0 and 3.0) The present invention also relates to a process for preparing a solid compound of Li2S comprising the use of the Li2S powder disclosed above.

[0019] The present invention also relates to compounds of formula (I), in particular Li6PS5Cl or Li3PS4, obtainable by the process described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] In this application: - any description, even if made in relation to a particular embodiment, is applicable and interchangeable with other embodiments of the invention; - when an element or component is said to be included in and / or selected from a list of enumerated elements or components, in the relevant embodiments expressly contemplated herein, it is to be understood that the element or component may be any one of the individual enumerated elements or components, or may also be selected from a group consisting of any two or more of the explicitly enumerated elements or components, and that any element or component enumerated in a list of elements or components may be omitted from such list; - Any recitation herein of numerical ranges by endpoints includes all numbers subsumed within the recited range, as well as the endpoints of the range and equivalents thereof.

[0021] The present invention relates to a process for obtaining lithium sulfide powder (LiS powder), such powder having certain unique technical features that make it well suited for use in the preparation of battery components such as lithium sulfide electrolytes, including lithium argyrodite.

[0022] The process of the invention for producing said Li2S powder advantageously comprises at least a) d less than 10 μm 50 providing a powder of lithium hydroxide (LiOH powder A) having a value of 0.01% by weight and exhibiting a residual water content of less than 5% by weight; b) reacting such LiOH powder A with a sulfide reactant to obtain a Li2S powder Includes.

[0023] Advantageously, the process of the present invention does not involve solvents and / or diluents. In other words, during the reaction under step b), no solvents and / or diluents are added to the reaction vessel. This is advantageous since steps to remove the solvents increase the complexity of the industrial process and its overall cost.

[0024] It is understood that the process according to the invention can be carried out in the presence of very small amounts of solvent, i.e. less than 5% by weight based on the total weight of the reaction mixture. Preferably, according to this embodiment, the amount of solvent is less than 4%, less than 3%, less than 2%, less than 1%, less than 0.5%, less than 0.1%, less than 0.01% or less than 0.001% by weight of solvent based on the total weight of the reaction mixture. The total weight of the reaction mixture is obtained by adding the weights of the reactants.

[0025] In addition, advantageously, no catalyst is added in the process of the present invention. The term "catalyst" as used in this specification and in the following claims is intended to indicate any compound capable of increasing the rate of the reaction under step b). For example, said catalyst may be selected from cobalt oxide, nickel oxide, molybdenum oxide and mixtures thereof, and may or may not be supported, for example, on silica, alumina or activated carbon.

[0026] The process of the present invention comprises at least two steps: a) d less than 10 μm 50 providing a powder of lithium hydroxide (LiOH powder A) having a water content of less than 5% by weight and a residual water content of less than 5% by weight; b) reacting such LiOH powder A with a sulfide reactant to obtain Li2S powder; and LiOH Powder A is prepared by a combination of at least two steps: grinding and heating at a temperature less than 180° C.

[0027] These two steps of grinding and heating can be carried out in any order: grinding and then heating, or heating and then grinding.

[0028] One important difference in the process of the present invention is the reduction in particle size of the lithium hydroxide powder prior to carrying out step b) of reacting the lithium hydroxide powder with the sulfide reactant.

[0029] One other important difference is that the resulting LiOH is less reactive towards the sulfide source and drying is carried out at a lower temperature compared to and in contrast to the processes described in the prior art where the lithium hydroxide powder is heated at a lower temperature.

[0030] The process of the present invention is advantageous in this respect since the heating step is carried out at a temperature below 180° C., thereby reducing the overall process cost. Contrary to the opinion that LiOH powder should be heated to high temperatures above 200° C. due to its reactivity with sulfur, the inventors have found that heating lithium hydroxide powder at temperatures below 180° C. produces a product of the formula LiLi a P.S. b X c It has been recognized in practice that the present invention provides Li2S powder with an advantageous set of properties, including pore volume, for the preparation of high quality solid compound (I).

[0031] Without wishing to be bound by any theory, this advantageous set of properties is due to the combination of heating and grinding steps to prepare the lithium hydroxide powder prior to use in the Li2S process. Under said two steps, the lithium hydroxide powder is reduced in size and exhibits a unique level of agglomeration as determined by measuring its pore volume. The use of low temperatures is not only advantageous from a cost control standpoint, but also allows for the production of Li2S powder that is well suited for use in the preparation of solid electrolytes.

[0032] Preferably, step a) of the process of the present invention comprises a d 50 The method includes providing a LiOH powder A having a water content of less than 5% by weight and exhibiting a residual water content of less than 5% by weight.

[0033] In some embodiments, the d of LiOH powder 50 In some embodiments, the d of the LiOH powder is less than 10 μm, less than 8 μm, less than 6 μm, less than 4 μm, or even less than 2 μm. 50 The value is at least 100 nm, at least 200 nm or even at least 300 nm.

[0034] In some embodiments, the residual water content of LiOH powder A is less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, or even less than 0.1 wt%, based on the total weight of the LiOH powder. In some embodiments, the residual water content of LiOH powder A is greater than 0.001 wt%, or greater than 0.01 wt%.

[0035] The LiOH powder A of step a) can be obtained by two alternative embodiments.

[0036] According to a first embodiment, the LiOH powder A is prepared by a combination of at least the following two steps: d less than 1 / 10μm 50 To obtain a powder of lithium hydroxide monohydrate (LiOH.HO) (LiOH powder C) with a d value of more than 10 μm, 50 grinding a powder of lithium hydroxide monohydrate (LiOH.HO) having a value of 0.1 to 0.25, and 2 / Heating such LiOH powder C at a temperature below 180° C. to obtain LiOH powder A.

[0037] According to a second embodiment, the LiOH powder A is prepared by a combination of at least the following two steps: heating a powder of lithium hydroxide monohydrate (LiOH.HO) exhibiting a residual water content of more than 5% by weight at a temperature of less than 180° C. to obtain a powder of lithium hydroxide exhibiting a residual water content of less than 1′ / 5% by weight (LiOH powder D); 2' / Grinding such LiOH powder D to obtain LiOH powder A.

[0038] According to these two embodiments, the heating step is carried out at a temperature below 180° C. Such a temperature may for example be below 170° C., below 160° C., below 150° C., below 140° C., below 130° C., below 120° C., below 110° C. and even below 100° C. The heating step may for example be carried out at a temperature of 80° C.

[0039] Preferably, such a heating step is carried out in the absence of air. The heating step is advantageously carried out under vacuum and / or by flowing an inert gas over or through the powder.

[0040] The duration of the heating step is not limited and can be as long as necessary to reach the expected residual water content, for example, the heating step can last from 1 to 24 hours.

[0041] According to these two embodiments, the grinding step is carried out to obtain a d 50 This is done so as to obtain a powder having a value.

[0042] To carry out such grinding, any type of equipment can be used: reference can be made, for example, to rotor-stator grinders, planetary ball mills or attritors.

[0043] The duration of the grinding process is not limited and can be determined according to the expected 50 The grinding process may be continued for as long as necessary to reach a desired value, for example, for 1 to 24 hours.

[0044] Preferably, the second step b) of the process comprises reacting such LiOH powder A with a sulfide reactant to obtain Li2S powder.

[0045] Step b) is preferably carried out at a temperature ranging from 100 to 260°C, for example ranging from 110 to 250°C or from 120 to 240°C.

[0046] The sulfide reactant may be selected from the group consisting of hydrogen sulfide, elemental sulfur, carbon disulfide, mercaptans, sulfur nitrides, organic sulfides and organic disulfides. Hydrogen sulfide is preferred, and gaseous hydrogen sulfide (H2S) is more preferred.

[0047] The reaction takes place in a vessel in which the LiOH powder is contacted with a sulfide reactant, for example H2S gas. The reaction vessel is preferably equipped with stirring blades. The reactor can be a vertical vessel in which the reactants are placed at the bottom of the reactor. Other types of reactors can also be used, for example horizontal reactors such as dryers or extruders. The reactor is preferably sealed. The volume of the reactor is not limited. The reaction can be carried out at subatmospheric or superatmospheric pressures, for example a pressure of 0.05 MPa or a pressure of 1 MPa can be used. The reactor is equipped with at least one heating means. The heating means maintains the temperature of the inner wall of the reactor in contact with the feedstock. The reactor can be equipped with additional heating means, for example a second heating means that can be located at the top of the reactor. The reactor is also equipped with a means for injecting a sulfide reactant, for example gaseous H2S.

[0048] Step b) is preferably carried out with stirring of the LiOH powder A. In this case, the vessel is equipped with a stirring blade or conveying stirrer, for example with d / D>0.9 (d is the size of the stirring blade and D is the inner diameter of the vessel), which is arranged as close as possible to the bottom and / or to the wall of the reactor.

[0049] Water is preferably removed during step b), which can be achieved by installing a condenser in the gas outlet line of the vessel, in which case the water in gaseous state becomes liquid (condenses) and is collected outside the vessel.

[0050] The process of the present invention can be continuous or it can be batchwise.

[0051] The present invention provides a d 50 value (measured by laser diffraction in paraxylene), 5m 2 / g (measured by nitrogen gas adsorption using the Brunauer-Emmett-Teller (BET) method), with a specific surface area of ​​0.035 cm 3The present invention also relates to a LiS powder characterized by having a total pore volume of greater than 20 nm / g (as measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) and a percentage of the total pore volume made up of pores with diameters less than 20 nm (as measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model with FAAS correction) of greater than 20%.

[0052] Such Li2S powders can in particular be produced by the process of the present invention.

[0053] The inventors have discovered that, without additional processing steps (e.g., grinding), the compound of formula Li a P.S. b X c It has been possible to identify a combination of raw materials and steps resulting in a Li2S powder that is directly ready for use in a process for preparing the solid compound of (I).

[0054] Surprisingly, the LiS powder obtained from the process according to the invention has the formula Li a P.S. b X c These are characterised by a degree of agglomeration which makes them well suited for the preparation of solid compounds of the type described above.

[0055] In the context of the present invention, agglomerated particles are characterized by their pore volume, and the term "agglomerated particles" is intended to mean combined divided particles organized into larger, mechanically stronger particles. More precisely, such degree of agglomeration of particles is characterized by the specific surface area measured by nitrogen gas adsorption according to the Brunauer-Emmett-Teller (BET) method, the total pore volume measured by nitrogen gas adsorption according to the Harkins and Jura method of the BJH model, both with FAAS correction, and the measurement of the percentage of the total pore volume made up of pores with a diameter of less than 20 nm.

[0056] The Li2S powder of the present invention has a d measured by laser diffraction in paraxylene. 50 According to the present invention, the Li2S powder is characterized by the d value. 50In some embodiments, the d value of the Li2S powder is less than 10 μm, less than 8 μm, less than 6 μm, less than 4 μm, or even less than 2 μm. 50 The value is at least 100 nm, at least 200 nm or even at least 300 nm.

[0057] The Li2S powder of the present invention is characterized by its high specific surface area as measured by nitrogen gas adsorption using the Brunauer-Emmett-Teller (BET) method. According to the present invention, the specific surface area of ​​the Li2S powder is 5.0 m 2 / g, 5.5m 2 / g, 6.0m 2 / g, 6.5m 2 / g or more than 6.9m 2 In some embodiments, the specific surface area of ​​the Li2S powder is greater than 40 m 2 / g, less than 35m 2 / g or less than 30m 2 / g.

[0058] The Li2S powder of the present invention is characterized by a high total pore volume. According to the present invention, the total pore volume of the Li2S powder is less than 0.035 cm 3 / g, 0.039cm 3 / g, 0.042cm 3 > / g, 0.045cm 3 / g or even 0.049 cm 3 In some embodiments, the total pore volume of the Li2S powder is greater than 1.0 cm 3 / g, less than 0.80cm 3 / g or less than 0.50 cm 3 / g.

[0059] The Li2S powder of the present invention is characterized by a high pore distribution. According to the present invention, the pore distribution of the Li2S powder is such that the pore volume of pores with a diameter of less than 20 nm is at least 20%, at least 30%, at least 35%, at least 40%, or even at least 45%. In some embodiments, such a pore distribution is less than 100%, less than 99%, or even less than 98%.

[0060] The Li2S powder of the present invention may be characterized by any one or several of the following features: - d > 0.05 μm as measured by laser diffraction in paraxylene 10 Values ​​such as d greater than 0.07 μm, greater than 0.09 μm or greater than 0.1 μm 10 value, - d less than 50 μm, measured by laser diffraction in paraxylene 90 d value, e.g., less than 40 μm, less than 30 μm, less than 20 μm, or less than 15 μm 90 value.

[0061] Thus, the present invention features novel Li2S particles in the form of particles or powders, characterized by their size and degree of agglomeration, which may be substantially spherical. Such Li2S particles can be further reacted, e.g., to form Li a P.S. b X c This shows a remarkable ability of dispersion and deagglomeration when involved in the preparation of the solid compound (I) of the present invention. This is advantageous because the particles of the solid compound (I) produced from the Li2S powder according to the present invention do not need to be milled before being used in the battery formulation, since this may lead to a decrease in their electrical conductivity.

[0062] One aspect of the present invention is a compound of formula (I): Li a P.S. b X c (I) (In the formula, - X represents at least one halogen element; - a is a number between 3.0 and 6.0, - b is a number between 3.5 and 5.0, and - c represents a number between 0 and 3.0) The present invention also relates to a process for preparing a solid compound of the formula (I) comprising the use of the lithium sulfide powder of the present invention.

[0063] For clarity, the numbers a, b and c may be integers or non-integer / fractional numbers, with the endpoints of the ranges and equivalents being included in the ranges.

[0064] In some embodiments, such a process comprises: - mixing starting materials (lithium hydroxide powder, sulfide reactant, phosphorus-containing material and halogen-containing material) in dry or slurried form, including the lithium sulfide powder of the present invention, and optionally applying mechanical energy to provide a mixture; - optionally drying the mixture; - optionally compressing the resulting dry mixture into pellets; - heating the optionally dried mixture or pellets to a temperature comprised between 350°C and 550°C for a period of at least 2 hours, for example 4 hours, 6 hours, 8 hours, 10 hours or 12 hours. Includes.

[0065] In some embodiments, such a process comprises at least one step for preparing a solution S1 at a temperature T1 comprised between −200° C. and 10° C., said solution S1 comprising a solvent as well as at least (PS4) 3- P species in the form of Li + Li species in the form of X - and the remaining sulfur in the form of the lithium sulfide powder of the invention, and then removing at least a portion of the solvent from the solution S1 to obtain Li a P.S. b X c The method includes the step of obtaining

[0066] According to these embodiments, solution S1 can be obtained by mixing lithium sulfide, phosphorus sulfide and a halogen compound according to the present invention in a solvent at a temperature comprised between -200°C and 10°C, preferably between -110°C and -10°C, in particular between -100°C and -50°C.

[0067] Alternatively, solution S1 can be obtained from the following steps: 1 / obtaining a precursor solution by mixing lithium sulfide according to the invention and a halogen compound in a solvent; and 2 / adding phosphorus sulfide to said precursor solution, at a temperature comprised between -200°C and 10°C, to obtain said solution S1.

[0068] The step for removing at least a portion of the solvent from S1 can be carried out at a temperature comprised between 30° C. and 200° C. The preparation of solution S1 is carried out in an inert atmosphere, under vacuum or under a stream of H2S.

[0069] The Li obtained in this way a P.S. b X c It may then be heat treated at a temperature comprised between 150°C and 700°C.

[0070] The solvent used in such processes is Li a P.S. b X c It is preferable that the solvent is capable of dissolving lithium sulfide, phosphorus sulfide and halogen compounds. It may be, for example, an aliphatic alcohol selected from the group consisting of ethanol, methanol and mixtures thereof.

[0071] The halogen compound is preferably selected from the group consisting of LiCl, LiBr, LiI and LiF.

[0072] Solution S1 contains 1 mole of Li with respect to the total moles of lithium sulfide added to the solvent. + At least 50 mol % of Li species in the form of + At least 80 mol % of Li species in the form of + The Li species may comprise at least 95 mol % of the Li species in the form:

[0073] Solution S1 is (PS4) relative to the total molar amount of phosphorus sulfide added in the solvent. 3- At least 50 mol % of P species in the form of (PS4) 3- At least 80 mol % of P species in the form of (PS4) 3- The P species may comprise at least 95 mol % of the P species in the form:

[0074] Solution S1 contains X moles of halogen compounds added to the solvent. - At least 50 mol % of X species in the form - At least 80 mol % of X species in the form of - The compound may comprise at least 95 mol % of species X in the form:

[0075] The present invention relates to compounds of formula Li, which can be obtained by the method described herein. a P.S. b X c (I) (In the formula, - X represents at least one halogen element; - a is a number between 3.0 and 6.0, - b is a number between 3.5 and 5.0, and - c represents a number between 0 and 3.0) The present invention also relates to compounds of the formula:

[0076] The present invention ultimately relates to: Li6PS5X, obtainable by the process described herein, where X is a halogen; - Li3PS4 obtained by the method described herein, - As a solid electrolyte, Li a P.S. b X c , for example the use of Li6PS5X and Li3PS4 as described herein; - Such a Li a P.S. b X c , such as the solid electrolytes described herein, including Li6PS5X and Li3PS4; - Li a P.S. b X c , for example electrochemical devices comprising Li6PS5X and Li3PS4 as described herein; - a solid-state battery comprising the solid electrolyte described herein; and - a vehicle comprising a solid-state battery as described herein.

[0077] 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, the statements of this application shall control.

Claims

1. d less than 10 μm ５０ value (measured by laser diffraction in p-xylene), more than 5 m ２ / g specific surface area (measured by nitrogen gas adsorption by the Brunauer-Emmett-Teller (BET) method), more than 0.035 cm ３ / g total pore volume (measured by nitrogen gas adsorption by the Harkins and Jura method of the BJH model using FAAS correction) and more than 20% of the proportion of the total pore volume composed of pores with a diameter of less than 20 nm (measured by nitrogen gas adsorption by the Harkins and Jura method of the BJH model using FAAS correction) of lithium sulfide powder (Li ２ S powder), a process for obtaining a) d less than 10 μm ５０ providing a powder of lithium hydroxide (LiOH powder A) having a value and showing a residual water content of less than 5% by weight b) the Li ２ Step of reacting the LiOH powder A with a sulfide reactant to obtain the Li S powder comprising, wherein the LiOH powder A is - d less than 10 μm ５０ To obtain a powder of lithium hydroxide monohydrate (LiOH·H ２ O) having a d value of more than 10 μm (LiOH powder C), a step of pulverizing a powder of lithium hydroxide monohydrate (LiOH·H ５０ O) having a d value of more than 10 μm (LiOH powder B), and a step of heating the LiOH powder C at a temperature of less than 180°C to obtain the LiOH powder A, or ２ ​ To obtain a lithium hydroxide powder (LiOH powder D) showing a residual water content of less than -5% by weight, a lithium hydroxide monohydrate (LiOH·H ２ O) powder is heated at a temperature of less than 180°C and the step of pulverizing the LiOH powder D to obtain the LiOH powder A obtained by, a process.

2. The heating step is carried out at a temperature of less than 170 °C, preferably less than 150 °C, the process according to claim 1.

3. The solvent, and / or diluent, and / or catalyst are not added to the reaction vessel during the reaction under step b), the process according to claim 1.

4. The sulfide reactant used in step b) is gaseous hydrogen sulfide (H ２ S), the process according to claim 1.

5. Step b) is - in a reactor equipped with at least one heating means, at a temperature varying from 100 °C to 260 °C, and / or - in a reactor equipped with a stirring blade or a conveying stirrer arranged as close as possible to the bottom and / or the wall of the reactor, while stirring the LiOH powder A, and / or - carried out by removing water, the process according to claim 1.

6. The above-mentioned Li ２ S powder, as measured by laser diffraction in p-xylene, - d exceeding 0.05 μm １０ value, and / or - d less than 50 μm ９０ value being such as to have, the process according to claim 1.

7. d less than 10 μm ５０ A process for obtaining a powder of lithium hydroxide having a ５０ d value (measured by laser diffraction in p-xylene) greater than 10 μm, the process comprising grinding a lithium hydroxide powder having a d value greater than 10 μm, wherein the lithium hydroxide powder exhibits a residual water content of less than 5% by weight.

8. d less than 10 μm ５０ value (measured by laser diffraction in p-xylene), more than 5 m ２ / g specific surface area (measured by nitrogen gas adsorption by the Brunauer-Emmett-Teller (BET) method), more than 0.035 cm ３ / g total pore volume (measured by nitrogen gas adsorption by the Harkins and Jura method of the BJH model using FAAS correction) and more than 20% of the proportion of the total pore volume composed of pores with a diameter of less than 20 nm (measured by nitrogen gas adsorption by the Harkins and Jura method of the BJH model using FAAS correction) of lithium sulfide powder (Li ２ 2S powder).

9. - d values greater than 0.05 μm, measured by laser diffraction in p-xylene １０ values, and / or - d, measured by laser diffraction in paraxylene, less than 50 µm ９０ value having, the powder according to claim 8.

10. The powder according to claim 8, which can be obtained by the process according to claim 1.

11. Formula (I): Li ａ PS ｂ X ｃ (I) (wherein - X represents at least one halogen element, - a represents a number from 3.0 to 6.0, - b represents a number from 3.5 to 5.0, and - c represents a number from 0 to 3.0) A process for preparing a solid compound of - mixing a starting material in a dry or slurry state comprising the lithium sulfide powder according to claim 8 to provide a mixture, - optionally, drying the mixture, - optionally, compressing the obtained dry mixture into pellets, - heating the optionally dried mixture or the pellets at a temperature comprised between 350 °C and 550 °C for a period of at least 2 hours comprising a process.

12. At least one step for preparing a solution S1 at a temperature T1 included in the range of -200°C to 10°C, wherein the solution S1 comprises a solvent and at least (PS ４ ) ３－ species of P in the form of, Li ＋ species of Li in the form of, X － species of X in the form of and the remaining sulfur in the form of the lithium sulfide powder according to claim 8, at least one step, and then removing at least a part of the solvent from the solution S1 to obtain Li ａ PS ｂ X ｃ The process according to claim 11, comprising the step of obtaining.

13. Formula (I): Li ａ PS ｂ X ｃ (I) (wherein - X represents at least one halogen element, - a represents a number from 3.0 to 6.0, - b represents a number from 3.5 to 5.0, and - c represents a number from 0 to 3.0) Use of the lithium sulfide powder according to claim 8 for preparing a solid compound of

14. The compound (I) is Li ６ PS ５ Cl or Li ３ PS ４ The use according to claim 13, wherein it is