Method for manufacturing lithium azirodite

Abstract

The present invention relates to a novel method for producing lithium argyrodite, as well as a product obtainable by said method, and in particular, its use as a solid electrolyte.

Description

Technology Field

[0001] The present invention relates not only to a method for manufacturing lithium argyrodite, but also to the product as obtained, and specifically to the use of said product as a solid electrolyte. Background Technology

[0002] Lithium batteries are used to power portable electronic devices and electric vehicles due to their high energy and power density. Conventional lithium batteries use a liquid electrolyte composed of lithium salts dissolved in an organic solvent. The aforementioned system poses safety issues because the organic solvent is flammable. Lithium dendrites forming and passing through the liquid electrolyte medium can cause short circuits and generate heat, leading to accidents resulting in serious damage.

[0003] Non-flammable inorganic solid electrolytes provide a solution to safety issues. Furthermore, their mechanical stability inhibits lithium dendrite formation, prevents self-discharge and heating problems, and helps extend battery life.

[0004] 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 electrode materials by cold pressing, which eliminates the need for a high-temperature assembly step. The elimination of the high-temperature sintering step removes one of the challenges associated with using lithium metal anodes in lithium batteries.

[0005] Therefore, there is a need for new solid sulfide electrolytes.

[0006] Argyrodite has long been known and is derived from argyrodite Ag8GeS6, which was first described by C. Winkler in 1886, and its analysis led to the discovery of germanium. The argyrodite family consists of more than 100 crystalline solids, including solid-state compounds in which, for example, silver is replaced by copper, germanium is replaced by gallium or phosphorus, and sulfur is replaced by selenium. Thus, Nitsche, Kuhs, Krebs, Evain, Boucher, Ptzner, and Nilges, in particular, describe compounds such as Cu9GaS6, Ag7PSe6, and Cu8GaS5Cl, which have a solid structure derived from argyrodite.

[0007] Most lithium azirodite, specifically Li6PS5Cl, as reported in the literature, is produced through dry or wet mechanochemical routes.

[0008] To date, all solution routes proposed in the literature mostly start from a pre-formed Li3PS4 dissolved in ethanol, followed by the introduction of Li2S and LiCl, or the dissolution of a pre-formed Li6PS5Cl.

[0009] Therefore, there is a need for a complete solution pathway for the manufacture of sulfide-based solid electrolytes. The problem to be solved

[0010] The object of the present invention is to provide a sulfide-based solid electrolyte having an azirodite structure, which is manufactured by a synthesis route that is preferably faster and easier to set up compared to the previously described method.

[0011] The object of the present invention is to provide a novel manufacturing process for lithium azylodite in a solution state, which preferably has improved productivity and enables control of the morphology of the obtained product. means of solving the problem

[0012] Accordingly, the present invention relates to a method for manufacturing Li6PS5X (wherein X is a halogen), wherein the method comprises at least one step of preparing a solution S1 at a temperature T1 included in -200°C to 10°C, preferably -110°C to 0°C, said solution S1 comprises a solvent, and at least (PS4) 3- P species of the form, Li + Li species of the form X - The method comprises a step of including X species of the form and the remainder of sulfur in the form of polysulfide, followed by a step of removing at least a portion of the solvent from the solution to obtain Li6PS5X.

[0013] The present invention also relates to Li6PS5X (where X is a halogen) which is easily obtained by the method of the present invention. The present invention also relates to the use of such Li6PS5X as a solid electrolyte. The present invention also relates to a solid electrolyte comprising such Li6PS5X, and an electrochemical device comprising Li6PS5X according to the present invention. The present invention also relates to a solid-state battery comprising the solid electrolyte of the present invention, and a vehicle comprising the solid-state battery. Brief explanation of the drawing

[0064] Brief explanation of the drawing Specific details for implementing the invention

[0014] definition

[0015] Throughout this specification, unless otherwise required by the context, the words “comprise” or “include,” or variations such as “comprising,” “comprising,” “comprising,” and “comprising,” will be understood to imply that they include the mentioned elements or method steps or groups of elements or method steps, but do not exclude any other elements or method steps or groups of elements or method steps. According to a preferred embodiment, the words “comprise” and “comprising,” and variations thereof, mean “to be exclusively composed of.”

[0016] As used herein, the singular forms (“a,” “an,” and “the”) include plural referents unless the context clearly indicates otherwise. The term “and / or” includes the meanings of “and” and “or,” and all other possible combinations of elements associated with this term.

[0017] The term "or" should be understood to include a limit.

[0018] Ratios, concentrations, amounts, and other numerical data may be presented in the form of ranges in this specification. It should be understood that such range forms are used merely for convenience and brevity and should be interpreted flexibly to include not only the numeric values ​​explicitly mentioned as limits of the range, but also all individual numeric values ​​or sub-ranges included within such ranges as if each numeric value and sub-range were explicitly mentioned. For example, a temperature range of about 120°C to about 150°C should be interpreted to include not only the explicitly mentioned limits of about 120°C to about 150°C, but also sub-ranges, e.g., 125°C to 145°C, 130°C to 150°C, etc., and individual amounts (including fractional amounts) within such specified ranges, e.g., 122.2°C, 140.6°C, and 141.3°C.

[0019] The term "electrolyte" specifically refers to ions, for example, Li + It refers to a material that allows [substances] to move through it, but prevents electrons from being conducted through it. Electrolytes are ions, for example, Li + It is useful for electrically insulating the cathode and anode of a battery while enabling them to be transported through the electrolyte. Specifically, the "solid electrolyte" according to the present invention is, while the material is in a solid state, ions, e.g., Li + It refers to any kind of material that can move around.

[0020] The term “electrochemical device” specifically refers to a device that generates and / or stores electrical energy by, for example, electrochemical and / or electrostatic processes. Electrochemical devices may include electrochemical cells, such as batteries, particularly solid-state batteries. Batteries may be primary (i.e., single-use or “disposable”) batteries or secondary (i.e., rechargeable) batteries.

[0021] As used herein, the terms “vehicle,” “vehicle,” or other similar terms are understood to include powered vehicles, generally, e.g., passenger cars (including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, vessels (including various boats and ships), aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As mentioned herein, a hybrid vehicle is a vehicle having two or more different power sources, e.g., a gasoline-powered and an electric-powered vehicle.

[0022] Detailed description of the invention

[0023] The method of the present invention is based on the preparation of a homogeneous solution containing ionic species. Therefore, it does not contain a suspension.

[0024] Therefore, all species involved in the production of Li6PS5X are dissolved in the solvent and are in the form of ionic species as mentioned above.

[0025] The essential feature of the method of the present invention is the temperature T1 as defined above. Accordingly, the method of the present invention is performed at a low temperature, which is particularly, in a solution (PS4) at the required temperature. 3- The purpose is to stabilize the species and thereby obtain solution S1.

[0026] Once solution S1 is prepared, a step is performed to remove at least a portion of the solvent. Then, Li6PS5X is obtained as a solid, preferably as a powder.

[0027] Preferably, the term "at least a portion of the solvent" refers to at least 50 weight percent, preferably at least 60 weight percent, of the solvent.

[0028] (PS4) 3- P species of the form are preferably obtained from a precursor selected from the group consisting of: P2S5, P4S 10 , P4S9 and P4S 9+x (here, 0 <x<1).

[0029] Li + Li species of the form are preferably obtained from a precursor selected from the group consisting of: Li2S and LiHS.

[0030] X - The X species of the form is preferably obtained from a precursor selected from the group consisting of: LiF, LiCl, LiBr, and LiI.

[0031] The remaining sulfur in the form of polysulfide is preferably obtained from a precursor selected from the group consisting of: P2S5, P4S10 , P4S9, P4S 9+x (here, 0 <x<1), Li2S, S 및 LiHS.

[0032] According to one embodiment, solution S1 as defined above is obtained by mixing lithium sulfide, phosphorus sulfide, and a halogen compound in a solvent at a temperature in the range of -200°C to 10°C, preferably -110°C to 0°C.

[0033] According to this embodiment, all species (Li, P, halogen, and S) are advantageously added together to the solvent at temperature T1.

[0034] According to another embodiment, solution S1 as defined above is obtained by performing the following steps:

[0035] - A step of obtaining a precursor solution by mixing lithium sulfide and a halogen compound in a solvent; and

[0036] - A step of obtaining solution S1 by adding phosphorus sulfide to the precursor solution at a temperature included in -200℃ to 10℃, preferably -110℃ to 0℃.

[0037] According to this embodiment, solution S1 is prepared in two steps, wherein the first step involves mixing lithium and a halogen compound.

[0038] The method of the present invention is easy to implement, specifically easier than the conventional method. For example, lithium sulfide can be used as is, even when it is obtained by carboreduction. In practice, lithium sulfide obtained from carboreduction containing residual carbon must undergo a filtration step to remove carbon and be used directly in the solvent for the preparation of solution S1. This eliminates the need for an intermediate lithium sulfide isolation step.

[0039] Preferably, the step of removing at least a portion of the solvent from solution S1 is performed at a temperature ranging from 30°C to 200°C, preferably from 30°C to 185°C, for example from 30°C to 100°C. According to one embodiment, this temperature may range from 35°C to 65°C.

[0040] The step of removing the solvent can be performed by implementing conventional means, specifically by solvent evaporation.

[0041] This desirable temperature range for solvent removal is advantageous in that secondary reactions are not promoted at such temperature values.

[0042] The preparation of solution S1 can take place in an inert atmosphere, under vacuum, or under an H2S flow.

[0043] The method of the present invention may include an additional step of heat treatment of Li6PS5X, particularly after a step for removing a solvent. Preferably, after removing the solvent, Li6PS5X is then heat-treated at a temperature included in the range of 150°C to 700°C, preferably about 550°C.

[0044] Therefore, such an additional step is advantageously performed by heat treatment of the solid Li6PS5X obtained after the solvent removal step.

[0045] Preferably, the solvent used in the method of the present invention can dissolve Li6PS5X, lithium sulfide, phosphorus sulfide, and halogen compounds. Thus, as mentioned above, such a solvent provides a homogeneous solution S1 as previously defined.

[0046] According to a preferred embodiment, the solvent is an aliphatic alcohol. Most preferably, the solvent is selected from the group consisting of ethanol, methanol, and mixtures thereof.

[0047] The temperature T1 is between -200°C and 10°C, preferably between -110°C and 0°C, most preferably between -110°C and -10°C, specifically between -100°C and -50°C, particularly between -90°C and -70°C. For example, T1 is about -80°C.

[0048] According to a specific embodiment, the temperature used during the step of removing at least a portion of the solvent from solution S1 is included in the range of 35°C to 65°C, and the temperature T1 is included in the range of -110°C to -10°C, preferably -100°C to -50°C.

[0049] Specifically, during the preparation of solution S1, the temperature T1 is maintained constant.

[0050] Advantageously, the method according to the present invention enables global and local differences with respect to stoichiometry to be much smaller, and even to be non-existent.

[0051] Lithium sulfide is a compound that generally comprises one or more sulfur atoms and one or more lithium atoms, or alternatively, one or more sulfur-containing ionic groups and one or more lithium-containing ionic groups. In a preferred specific embodiment, lithium sulfide may consist of a sulfur atom and a lithium atom.

[0052] Phosphorus sulfide is a compound that generally comprises one or more sulfur atoms and one or more phosphorus atoms, or alternatively, one or more sulfur-containing ionic groups and one or more phosphorus-containing ionic groups. In a preferred specific embodiment, phosphorus sulfide may consist of a sulfur atom and a phosphorus atom. Examples of phosphorus sulfide include P2S5, P4S3, and P4S 10 , P4S4, P4S5, P4S6, P4S7, P4S8 and P4S9 may be included, but are not limited thereto.

[0053] A halogen compound is a compound comprising one or more halogen atoms, such as F, Cl, Br, or I, through chemical bonding (e.g., ionic or covalent bonding) to the other atoms constituting the compound. In a preferred specific embodiment, the halogen compound may comprise one or more F, Cl, Br, I, or combinations thereof, and one or more metal atoms. In another preferred embodiment, the halogen compound may comprise one or more F, Cl, Br, I, or combinations thereof, and one or more non-metal atoms. Non-limiting examples may suitably include metal halides, such as LiF, LiBr, LiCl, LiI, NaF, NaBr, NaCl, NaI, KaF, KBr, KCl, KI, etc. In a preferred specific embodiment, a halogen compound suitable for use in a solid electrolyte in an all-solid Li-ion battery may comprise one or more halogen atoms and Li.

[0054] Preferably, lithium sulfide may include lithium sulfide Li2S or is this, and phosphorus sulfide may include phosphorus pentasulfide P2S5 or is this.

[0055] The halogen compound defined above may be selected from the group consisting of LiCl, LiBr, LiI, LiF, and combinations thereof. Preferably, the halogen compound is LiCl.

[0056] Solution S1 contains at least 50 mol% of Li with respect to the total molar amount of lithium sulfide added to the solvent. + Li species of the form, preferably at least 80 mol% of Li + Li species of the form, more preferably at least 95 mol% of Li + It may include Li species of the form.

[0057] Solution S1 is at least (PS4) 3- and (P2S7) 4- It may include P species of the form.

[0058] Solution S1 contains at least 50 mol% (PS4) of the total molar amount of phosphorus sulfide added to the solvent. 3- P species of the form, preferably at least 80 mol% (PS4) 3- P species of the form, more preferably at least 95 mol% (PS4) 3- P species of the form, or even at least 99 mol% (PS4) 3- It may include P species of the form.

[0059] Solution S1 contains at least 50 mol% of X with respect to the total molar amount of halogen compounds added to the solvent. - X species of the form, preferably at least 80 mol% of X - X species of the form, more preferably at least 95 mol% of X - It may include X species of the form.

[0060] The present invention also relates to Li6PS5X (where X is a halogen) which can be easily obtained by the method defined above. Preferably, the present invention also relates to Li6PS5Cl which can be easily obtained by the method defined above.

[0061] The present invention also relates to the use of Li6PS5X, preferably Li6PS5Cl as defined above, as a solid electrolyte. The present invention also relates to a solid electrolyte comprising Li6PS5X, preferably Li6PS5Cl as defined above, in particular a sulfide-based solid electrolyte for lithium-ion batteries.

[0062] The present invention also relates to an electrochemical device comprising Li6PS5X as defined above. The present invention also relates to a solid-state battery comprising a solid electrolyte as defined above, such as an all-solid-state lithium secondary battery, and a vehicle comprising a solid-state battery as defined above.

[0063] Typically, a lithium solid battery comprises a positive active material layer containing a positive active material, a negative active material layer containing a negative active material, and a solid electrolyte layer formed between the positive active material layer and the negative active material layer. At least one of the positive active material layer, the negative active material layer, and the solid electrolyte layer comprises a solid electrolyte comprising Li6PS5X as defined above, preferably Li6PS5Cl.

[0065] Fig. 1: NMR data of Li6PS5Cl before annealing (Example 1). The asterisk indicates PS4 3- It corresponds to.

[0066] Fig. 2: NMR data of Li6PS5Cl before annealing (Example 1). The asterisk corresponds to Li in Li6PS5Cl.

[0067] Fig. 3: Reaction medium (solution S1) + 10% DMSO-d6 31 P solution NMR (Example 1). The asterisk indicates PS4 solvated by ethanol molecules. 3- It corresponds to.

[0068] Fig. 4: XRD data after synthesis (Example 1).

[0069] Fig. 5: NMR data of Li6PS5Cl after annealing at 550°C (Example 2). The asterisk indicates PS4 3- Corresponds to, and the circle is PO4 3- It corresponds to, the square corresponds to partially oxidized thiophosphate, and the other indication is an artifact (spinning side-band).

[0070] Fig. 6: NMR data of Li6PS5Cl after annealing at 550°C (Example 2). The asterisk corresponds to Li in Li6PS5Cl, and the circle corresponds to Li in Li3PO4.

[0071] Fig. 7:XRD data after annealing at 550℃ (Example 2).

[0072] Fig. 8: Conductivity measurement for Example 2.

[0073] Fig. 9: NMR 31 P data Li6PS5Cl (Example 3). The asterisk indicates PS4 3- It corresponds to, and the hexagon is P2S7 4- It corresponds to.

[0074] Fig. 10: 6 Li NMR data of Li6PS5Cl (Example 3). An asterisk corresponds to Li in Li6PS5Cl, and a triangle corresponds to Li2S.

[0075] Fig. 11: Reaction medium (solution S1) + 10% DMSO-d6 31 P solution NMR (Example 3). An asterisk indicates PS4 solvated by ethanol molecules. 3- It corresponds to.

[0076] Fig. 12: XRD data of the powder of Example 3.

[0077] Fig. 13: XRD data of the powder of Example 4.

[0078] Examples

[0079] The following examples serve to illustrate the invention but do not have limiting features.

[0080] X-ray diffraction:

[0081] XRD diffraction patterns of the powder were acquired on an XRD goniometer in Bragg-Brentano geometry using a Cu X-ray tube (Cu K-alpha wavelength = 1.5406 Å). This setup can be used with different optical configurations (i.e., equipped with variable or fixed diverging slits, or Soller slits). As with Panalytical's monochromator or Bragg-Brentano HD optical element, a filter device can also be used on the primary side. When a variable diverging slit is used, the typical illumination area is 10 mm × 10 mm. The sample holder is loaded onto a spinner, and the rotation speed is typically 60 rpm during acquisition. For the incident Bragg-Brentano HD optical element, the tube setting was operated at 40 kV / 30 mA for variable slit acquisition and at 45 kV / 40 mA for fixed slit acquisition. The acquisition step was 0.017° per step. The angle range was typically 5° to 90° at 2 theta or more. The total acquisition time was typically 30 minutes or more.

[0082] The powder was covered with a Kapton film to prevent reaction with moisture in the air.

[0083] Conductivity measurement:

[0084] Conductivity was obtained for pellets using a uniaxial press operating at 500 MPa.

[0085] This measurement is performed under a loading of 40 MPa, and two carbon foils are used as current collectors in an MTI pressure cell (BATTE-CELL-0067 EQ-PSC-15-P).

[0086] The impedance spectrum is acquired on the Biologic VMP3 device, and temperature control is ensured by the Binder climate chamber. A duration of 2 hours is set to allow the temperature to equilibrate between two measurements.

[0087] Impedance spectroscopy is acquired in PEIS mode using an amplitude of 10 mV and a frequency range of 1 MHz to 1 kHz (25 points per decade and an average of 50 measurements per frequency point).

[0088] Liquid NMR

[0089] 31 The NMR spectrum of the P solution was recorded on a Bruker 300 MHz spectrometer equipped with a QNP Z-GRD Z8352 / 107 probe. The relaxation time was 7 seconds. The spectrum is 1 It was decoupled from H.

[0090] Solid-phase NMR

[0091] Solid-state NMR spectra were recorded on a Bruker Avance 400 spectrometer equipped with a high-speed DVT4 probe. By performing magic-angle-spinning (MAS) at a speed of 10 kHz in single-pulse mode using a relaxation time D1 according to the experiment (see Examples below), 31 P and 6 Li measurements were performed in static, single-pulse mode using a relaxation time D1 = 120 seconds. 7 Li measurements were performed. 31 The reference for P NMR is 85% H3PO4, and 6 The reference for Li NMR is 5 mol L -1 It was an aqueous LiCl solution.

[0092] Example 1

[0093] LiCl (229 mg, Sigma-Aldrich) and Li2S (620 mg, Albemarle) were weighed into a 100 mL Schlenk flask in an Ar-filled glove box where both oxygen and moisture levels were less than 1 ppm. Subsequently, the flask was removed from the glove box and connected to the N2 / vacuum line. 35 mL of anhydrous ethanol (Merck Seccosolv) was added. ® , moisture content = less than 50 ppm) was added to this flask through a glass syringe. The resulting mixture was stirred under an inert atmosphere (N2). It took about 20 minutes until the reactants were completely dissolved.

[0094] P2S5 (600 mg, Sigma-Aldrich, 99% purity) was weighed into a 100 mL three-necked flask equipped with an addition funnel. It was cooled to -80°C for 30 minutes using a dry ice / acetone bath, and then the Li / S / Cl solution was transferred to the addition funnel and rapidly added. P2S5 dissolved in about 10 minutes, becoming a clear yellow solution.

[0095] Next, the solution was stirred for 6 hours while maintaining the temperature at -80℃. No further changes were observed. A 600 μL sample of the reaction medium 31 Samples were taken after 1, 3, and 6 hours for P NMR monitoring (Brucker 300 MHz spectrometer equipped with QNP Z-GRD Z8352 / 107 probe). Subsequently, the solvent was slowly removed under primary vacuum, first at room temperature, and then the temperature was increased to 50°C when the solution was concentrated to approximately 60% of its initial volume, and left at this temperature overnight. The obtained product was a pale yellow powder. It was subjected to powder X-ray diffraction (Panalytical), solid phase 31 P, 1 H and 6 Li MAS NMR, and solid phase 7It was characterized by Li static NMR (Brucker NEO 400 spectrometer equipped with a 4 mm BL4 probe).

[0096] Example 2

[0097] A quartz tube with a length of 250 mm, an inner diameter of 10 mm, and a wall thickness of 1.1 mm was sealed at one end using a torch fueled by propane and oxygen. This tube was placed in an Ar-filled glove box with oxygen and moisture levels of less than 1 ppm and filled with 250 mg of the material prepared according to Example 1 below. Subsequently, the tube was fitted with a PVC hose adapter that is closed by a valve, removed from the glove box, and connected to a vacuum line through the valve. The system was set under vacuum. When the vacuum reached 1 mbar, the tube was sealed using a propane / oxygen torch. The sealed tube was heated to 550°C in a muffle furnace at a ramp of 2°C / min and maintained at this temperature for 5 hours. After it cooled to 30°C, it was transferred to an Ar-filled glove box and cut using a tungsten carbide cutter to collect the product as a gray powder. X-ray diffraction of this powder, solid phase 31 P, 6 Li and 1 H MAS NMR and solid-phase static 7 It was characterized by Li NMR.

[0098] The lithium ion conductivity of the pellet of this material was measured by impedance spectroscopy, and it was σ = 1.3 x 10⁻⁶ at 30℃. -3 S.cm -1 It reaches , and at this point, the activation energy is 0.43 eV.

[0099] Example 3 (Comparative Example)

[0100] LiCl (229 mg, Sigma-Aldrich) and Li2S (620 mg, Albemarle) were weighed into a 100 mL Schlenk flask in an Ar-filled glove box where both oxygen and moisture levels were less than 1 ppm. Subsequently, the flask was connected to the N2 / vacuum line, and 35 mL of anhydrous ethanol (Merck Seccosolv) was added. ® , moisture content = less than 50 ppm) was added. The mixture was stirred under an inert atmosphere (N2).

[0101] P2S5 (600 mg, Sigma-Aldrich, 99% purity) was weighed into a 100 mL Schlenk flask equipped with an addition funnel. Subsequently, the Li / S / Cl solution was transferred to the addition funnel and rapidly added. P2S5 dissolved in approximately 10 minutes, becoming a clear yellow solution. Then, regarding 600 μL of reaction medium 31 The P NMR spectrum was recorded.

[0102] Next, the solution was stirred at room temperature (22°C) for 2 hours. No further changes were observed. After this time, an additional 600 μL sample of the solution was taken, and 31 It was characterized by P NMR. This solution is 31 As shown in the P solution NMR, it contains a high amount of impurities / by-products (Fig. 11), particularly the signal at 114 ppm. Subsequently, the solvent was removed under vacuum, first at room temperature, and then, when the solution was concentrated to approximately 60% of its initial volume—ultimately when most of the ethanol reached 80°C—the temperature was increased to 45°C and maintained at this temperature for an additional 3.5 hours. The obtained product was a white paste. Subsequently, this paste was heated to 100°C over a vacuum line for 3.5 hours and turned into a white powder. The obtained powder is 31 As shown in the solid-state NMR, it contains a high amount of impurities / by-products (Fig. 9).

[0103] Example 4

[0104] LiCl (344 mg, Sigma-Aldrich), Li2S (930 mg, Albemarle), and elemental sulfur (135 mg, AnalR NORMAPUR) ® VWR Chemicals) was weighed together into a 100 mL Schlenk flask in an Ar-filled glove box where both oxygen and moisture levels were less than 1 ppm. 30 g of anhydrous ethanol (VWR, moisture content less than 30 ppm) was added to the mixture. Subsequently, the flask was removed from the glove box and connected to the N2 / vacuum line. The resulting mixture was stirred under an inert atmosphere (N2) at 0°C (water / ice bath). It took about 15 minutes for the reactants to be completely dissolved, resulting in a dark yellow solution, which was then stirred for an additional 20 minutes at 0°C.

[0105] P2S5 (600 mg, Sigma-Aldrich, 99% purity) was weighed into a 100 mL Schlenk flask. The flask was cooled to -15°C over 30 minutes using a sodium chloride / ice bath, and then the Li / S / Cl solution was placed in Teflon ® It was added rapidly through a cannula. P2S5 dissolved in 5 minutes and became a dark yellow solution.

[0106] The solution was stirred for 3 hours and 45 minutes while maintaining the temperature between -15°C and -10°C. Subsequently, the reaction medium was set under dynamic primary vacuum, and the temperature was increased to 180°C (silicon bath on a hot plate) to remove the solvent. The temperature of 180°C was reached after 30 minutes and maintained at this temperature for an additional 2 hours. The obtained product was a dry gray powder. This powder was subjected to X-ray diffraction and solution 31 It was characterized by P NMR.

[0107] The lithium ion conductivity of the pellet of this material was measured by impedance spectroscopy, and it was σ = 1 x 10⁻⁶ at 30℃. -4 S.cm -1 It reaches , and at this point, the activation energy is 0.42 eV.

Claims

Claim 1 A method for preparing Li6PS5X (where X is a halogen), comprising at least one step of preparing a solution S1 at a temperature T1 included in the range of -200℃ to 10℃, wherein the solution S1 comprises a solvent, and at least (PS4) 3- P species of the form, Li + Li species of the form X - A method comprising the step of including X species of the form and the remainder of sulfur in the form of polysulfide, followed by the step of removing at least a portion of the solvent from the solution S1 to obtain Li6PS5X. Claim 2 A method according to claim 1, wherein the solution S1 is obtained by mixing lithium sulfide, phosphorus sulfide, and a halogen compound in a solvent at a temperature included in -200℃ to 10℃. Claim 3 Method of claim 1, wherein the solution S1 is obtained from the following steps: - a step of obtaining a precursor solution by mixing lithium sulfide and a halogen compound in a solvent; and - a step of obtaining the solution S1 by adding phosphorus sulfide to the precursor solution at a temperature included in -200°C to 10°C. Claim 4 A method according to any one of claims 1 to 3, wherein the step of removing at least a portion of the solvent from S1 is performed at a temperature included in 30°C to 200°C. Claim 5 A method according to any one of claims 1 to 3, wherein the preparation of the solution S1 takes place in an inert atmosphere, under vacuum, or under an H2S flow. Claim 6 A method according to any one of claims 1 to 3, wherein Li6PS5X is subsequently heat-treated at a temperature included in 150℃ to 700℃. Claim 7 A method according to any one of claims 1 to 3, wherein the solvent is capable of dissolving Li6PS5X, lithium sulfide, phosphorus sulfide, and halogen compounds. Claim 8 A method according to any one of claims 1 to 3, wherein the solvent is an aliphatic alcohol. Claim 9 A method according to any one of claims 1 to 3, wherein the solvent is selected from the group consisting of ethanol, methanol, and mixtures thereof. Claim 10 A method according to any one of claims 1 to 3, wherein the temperature T1 is included in -110℃ to 0℃, -110℃ to -10℃, or -100℃ to -50℃. Claim 11 A method according to claim 2 or 3, wherein the halogen compound is selected from the group consisting of LiCl, LiBr, LiI, and LiF. Claim 12 In claim 2 or 3, the solution S1 comprises at least 50 mol% of Li with respect to the total molar amount of lithium sulfide added to the solvent. + Li species of the form, at least 80 mol% of Li + Li species of the form, or at least 95 mol% of Li + A method comprising a Li species of the form. Claim 13 In paragraph 2 or 3, the solution S1 comprises at least 50 mol% (PS4) of the total molar amount of phosphorus sulfide added to the solvent. 3- P species of the form, at least 80 mol% (PS4) 3- P species of the form, or at least 95 mol% (PS4) 3- A method comprising a P species of the form. Claim 14 In paragraph 2 or 3, the solution S1 comprises at least 50 mol% of X with respect to the total molar amount of the halogen compound added to the solvent. - X species of the form, at least 80 mol% of X - X species of the form, or at least 95 mol% of X - A method comprising a type X of the form. Claim 15 A method according to any one of claims 1 to 3, wherein the temperature T1 is included in the range of -100℃ to -50℃, and the step of removing at least a portion of the solvent from the solution S1 is performed at a temperature included in the range of 35℃ to 65℃. Claim 16 delete Claim 17 delete Claim 18 delete Claim 19 delete Claim 20 delete Claim 21 delete

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