Method for producing LGPS-type solid sulfide electrolyte

Abstract

This invention relates to a method for producing an LGPS-type solid sulfide electrolyte. Surprisingly, the inventors have found that by heat-treating a mixed set of precursors at high temperature and pressure, a solid sulfide electrolyte can be obtained with high purity and a short reaction time.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a solid sulfide electrolyte and a solid sulfide electrolyte obtained from said method. [Background technology]

[0002] The rapid advancements in the development of small, lightweight electronic products, electronic devices, communication devices, and similar items, coupled with the widespread emergence of the need for electric vehicles in relation to environmental concerns, have created a demand for improved performance in rechargeable batteries used as power sources for these products. Among these, lithium-ion batteries are attracting attention as high-performance batteries due to their high energy density and high reference electrode potential.

[0003] However, the electrolytes conventionally used in lithium-ion batteries are liquid electrolytes such as organic solvents. Therefore, safety problems such as electrolyte leakage and fire risks can occur continuously.

[0004] Recently, solid-state batteries containing solid electrolytes instead of liquid electrolytes have been developed to improve the safety aspects of lithium-ion batteries and have attracted considerable attention. For example, solid electrolytes are generally safer than liquid electrolytes due to their non-flammable or flame-retardant properties.

[0005] The solid electrolyte may consist of oxide-based solid electrolytes, polymer-based electrolytes, and sulfide-based electrolytes. Sulfide-based electrolytes are commonly used due to their high lithium-ion conductivity range compared to oxide-based and polymer-based solid electrolytes, such as sulfide-based solid electrolytes having an argyrodite-type crystal structure or an LGPS-type crystal structure.

[0006] Efforts have been made to produce solid sulfur electrolytes with an LGPS-type crystal structure. Whiteley et al. (Journal of The Electrochemical Society 2014, 161, A1812-A1817) reported the synthesis of Li10SiP2S12 by ball milling a precursor mixture of Li2S, P2S5, and SiS2, subsequently pressing the ball mill powder at 375 MPa, and heat-treating this pressed powder at 550 °C for 8 hours. However, this synthesis protocol only yields a composition with 85% purity having 15% Li Si 0.2 P 0.8 S4 as a by-product. Hori et al. (Acta Cryst.2015,B71,727-736) disclosed the synthesis of Li 10.35 Si 1.35 P 1.65 S 12 by ball milling Li2S, P2S5, and SiS2, subsequently pelletizing the sample, and heating at 550 °C and 10 Pa for 72 hours. However, obtaining these LGPS-type electrolytes with high purity and short reaction times still remains a problem.

[0007] Therefore, there is a need to provide a manufacturing method for producing a solid sulfur electrolyte having an LGPS-type crystal structure.

Summary of the Invention

Problems to be Solved by the Invention

[0008] An object of the present invention is to provide a method for producing an LGPS-type solid sulfide electrolyte.

[0009] A further object of the present invention is to provide a solid sulfide electrolyte obtainable from the manufacturing method. [[ID=​​​​​

[0011] In a first aspect, an object of the present invention is to provide a method for producing a solid sulfide electrolyte represented by formula (I): Li 11-y X 2-y P 1+y S 12 (I) where 0 ≤ y < 2, preferably 0 ≤ y < 1, where X is Si, Ge, Sn, or a combination thereof, which is achieved by providing a manufacturing method for producing by mixing and heat-treating a set of a plurality of precursors at a temperature of at least 100 °C and a pressure of at least 1 MPa, preferably a pressure of 1 to 1000 Mpa.

[0012] The inventors have surprisingly found that by heat-treating the mixed set of the precursors at this high temperature and high pressure, as demonstrated in the attached examples, a solid sulfide electrolyte can be obtained with high purity and a short reaction time. In contrast, conventional firing processes that do not apply high pressure do not result in the formation of the solid sulfide electrolyte represented by formula (I).

[0013] While not wishing to be bound by any theory, the inventors believe that this manufacturing method enables the obtaining of samples with higher purity due to the fact that the combination of high temperature and high pressure results in complete interdiffusion of the atoms of the plurality of precursors and reduction of sulfur loss due to evaporation during the heat treatment process.

[0014] In a further aspect, the present invention provides a solid sulfide electrolyte obtainable by the manufacturing method according to the present invention.

[0015] In a further aspect, the present invention provides a battery comprising a solid sulfide electrolyte obtainable by the manufacturing method according to the present invention.

[0016] In a further aspect, the present invention provides the use of the solid electrolyte according to the present invention in a battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] [Figure 1] Figure 1 shows the X-ray diffraction pattern of conventional heat-treated ball-ground powder in a beryllium-capped dense cell. [Figure 2] Figure 2 shows the X-ray diffraction patterns of conventionally heat-treated and quenched ball-milled powders in a beryllium-capped dense cell. [Figure 3] Figure 3 shows the X-ray diffraction pattern of hot-pressed ball-ground powder in a beryllium-capped dense cell. [Modes for carrying out the invention]

[0018] The drawings and the following detailed description illustrate in detail preferred embodiments for enabling the implementation of the present invention. While the present invention is described with reference to these particular preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention includes numerous alternatives, variations, and equivalents, which will become apparent by considering the following detailed description and the accompanying drawings.

[0019] As used herein and in the claims, the term “comprising” should not be construed as limiting to the means listed thereafter, nor as excluding other elements or steps. It should be construed as specifying the presence of the described features, integers, steps, or components mentioned, but not as precluding the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Accordingly, the expression “composition comprising components A and B” should not be limited to a composition consisting solely of components A and B. This means that, with respect to the present invention, A and B are merely components that are relevant in the composition. Thus, the terms “comprising” and “including” encompass the more restrictive terms “consisting essentially of” and “consisting of.”

[0020] As used in this disclosure, the term “solid-state battery” refers to a cell or battery that comprises only solid or substantially solid components, such as solid electrodes (e.g., anode and cathode) and a solid electrolyte.

[0021] As used herein, the term "LGPS-type crystal structure" refers to a negatively charged PS4 3- and XS4 4- This refers to a cuboid crystal structure containing tetrahedra, where X is Si, Ge, or Sn, preferably Si. In some embodiments, preferably when X is Si, the LGPS crystal structure has lattice parameters of approximately a = 8.70 Å and c = 12.60 Å. In some embodiments, the LGPS type crystal structure can also be empirically measured by α, X-ray diffraction, for example, by observing peaks around 2θ = 20.18 ± 0.50°, 20.44 ± 0.50°, 26.96 ± 0.50°, and 29.58 ± 0.50° using CuK lines.

[0022] X-ray diffraction (XRD) as referred to in this disclosure refers to XRD experiments performed using a Bruker D8 diffractometer equipped with either θ-θ arranged Cu(Kα1-Kα2) or Mo(Kα1-Kα2) radiation. Preferably, an airtight sample holder with a Be window was used for the measurements. Preferably, the patterns were measured at 2θ = 10° to 50° with a step size of 0.02° at 25°C.

[0023] Manufacturing method As described above in the first aspect, the present invention is a method for producing a solid sulfide electrolyte: i) A step of preparing a set of precursors containing Li, X, P, and S, ii) A step of mixing the set of precursors to obtain a solid electrolyte mixture, iii) The process includes a step of heat-treating the solid electrolyte mixture at a temperature of at least 100°C and a pressure of at least 1 MPa, preferably 1 to 1000 MPa, to obtain a solid sulfide electrolyte, The solid sulfide electrolyte is represented by formula (I), Li 11-y X 2-y P 1+y S 12 (I) In the formula, 0 ≤ y < 2, preferably 0 ≤ y < 1. The present invention provides a method in which X is Si, Ge, Sn, or a combination thereof, preferably X is Si, Ge, or Sn, and preferably X is Si.

[0024] As will be understood by those skilled in the art, the precursor set may be configured to contain liquid or to contain essentially no liquid, and it is preferable that the precursor set be configured to contain essentially no liquid. The term “essentially no liquid” means that the precursor set contains less than 10% by weight of liquid relative to the total weight of the precursor set, preferably less than 7.5% by weight, more preferably less than 5% by weight, even more preferably less than 2.5% by weight, and most preferably less than 1% by weight of liquid relative to the total weight of the precursor set. In a more preferred embodiment, the precursor set contains less than 1000 ppm of liquid relative to the total weight of the precursor set, preferably less than 500 ppm, more preferably less than 100 ppm, even more preferably less than 50 ppm, and most preferably less than 10 ppm of liquid relative to the total weight of the precursor set.

[0025] In the context of this invention, a liquid is considered to be an organic compound or aqueous compound that is liquid under standard conditions of temperature and pressure as defined by IUPAC. Accordingly, the boiling point and melting point are considered to be the boiling point and melting point at standard atmospheric pressure, i.e., 101325 Pa. As will be understood by those skilled in the art, the presence of an organic liquid can be determined by thermogravimetric analysis (TGA) or nuclear magnetic resonance (NMR) spectroscopy, and the presence of liquid water can be measured by Karl Fischer titration.

[0026] As used in this disclosure, the term “solid electrolyte mixture” means an electrolyte mixture that is essentially free of any liquid. The term “essentially free of liquid” means that the solid electrolyte mixture contains less than 10% by weight of liquid, preferably less than 7.5% by weight, more preferably less than 5% by weight, even more preferably less than 2.5% by weight, and most preferably less than 1% by weight of the solid electrolyte mixture, relative to the total weight of the solid electrolyte mixture. In more preferred embodiments, the solid electrolyte mixture contains less than 1000 ppm of liquid, preferably less than 500 ppm, more preferably less than 100 ppm, even more preferably less than 50 ppm, and most preferably less than 10 ppm of the solid electrolyte mixture, relative to the total weight of the solid electrolyte mixture.

[0027] As used in this disclosure, the term “solid electrolyte” means an electrolyte that is essentially free of any liquid. The term “essentially free of liquid” means that the solid electrolyte contains less than 10% by weight of liquid, preferably less than 7.5% by weight, more preferably less than 5% by weight, even more preferably less than 2.5% by weight, and most preferably less than 1% by weight of solid electrolyte, relative to the total weight of the solid electrolyte. In more preferred embodiments, the solid electrolyte contains less than 1000 ppm of liquid, preferably less than 500 ppm, more preferably less than 100 ppm, even more preferably less than 50 ppm, and most preferably less than 10 ppm, relative to the total weight of the solid electrolyte.

[0028] A preferred embodiment is a production method according to the present invention, wherein the set of precursors is metallic lithium or elemental lithium, lithium sulfide (Li2S), lithium oxide (Li2O), lithium carbonate (Li2CO3), lithium hydrosulfide (LiHS), lithium trithiocarbonate (Li2CS3), lithium polysulfide (Li2Sx, where x = 2 to 100), phosphorus sulfides such as phosphorus trisulfide (P2S3) and phosphorus pentasulfide (P2S5), sodium phosphate (Na3PO4), Z is F, Cl, Br and I The elements selected from are phosphorus elemental substances such as PSZ3 and P4, phosphorus sulfides such as diphosphorus trisulfide (P2S3) and diphosphorus pentasulfide (P2S5), sodium phosphate (Na3PO4), and Z, which comprises one or more selected from the group consisting of phosphorus elemental substances such as PSZ3 and P4, lithium phosphate (Li3PS4), and X-containing compounds, and preferably the set of precursors comprises one or more selected from the group consisting of lithium sulfide, phosphorus sulfide, and X-containing compounds.

[0029] A more preferred embodiment is the production method according to the present invention, wherein the X-containing compound is element X or XS2, preferably XS2.

[0030] A preferred embodiment is a manufacturing method according to the present invention, wherein the set of precursors comprises lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), and XS2, preferably lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), and SiS2.

[0031] A very preferred embodiment is in which the precursor set consists of lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), and an X-containing compound; preferably, the precursor set consists of lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), and XS2; and more preferably, the precursor set consists of lithium sulfide (Li2S), diphosphorus pentasulfide (P2S5), and SiS2. 、 This is a manufacturing method according to the present invention.

[0032] According to a very preferred embodiment of the present invention, a solid sulfide electrolyte is provided in which at least 50 mol% of X represents Si, preferably at least 80 mol% of X represents Si, and most preferably X represents Si.

[0033] According to a very preferred embodiment of the present invention, a solid sulfide electrolyte is provided, where X represents Si, Ge, Sn, or a combination thereof, and at least 50 mol% of X represents Si, preferably at least 80 mol% of X represents Si.

[0034] According to a preferred embodiment of the present invention, a solid sulfide electrolyte is provided in which at least 50 mol% of X represents Ge, preferably at least 80 mol% of X represents Ge, and most preferably X represents Ge.

[0035] According to a preferred embodiment of the present invention, a solid sulfide electrolyte is provided, where X represents Si, Ge, Sn, or a combination thereof, preferably at least 50 mol% of X represents Ge, and at least 80 mol% of X represents Ge.

[0036] According to a preferred embodiment of the present invention, a solid sulfide electrolyte is provided in which at least 50 mol% of X represents Sn, preferably at least 80 mol% of X represents Sn, and most preferably X represents Sn.

[0037] According to a preferred embodiment of the present invention, a solid sulfide electrolyte is provided, where X represents Si, Ge, Sn, or a combination thereof, preferably at least 50 mol% of X represents Sn, and at least 80 mol% of X represents Sn.

[0038] A very preferred embodiment is the manufacturing method according to the present invention, wherein X = Si.

[0039] A preferred embodiment is a manufacturing method according to the present invention, wherein y ≤ 1 < 1, preferably 0.05 ≤ y ≤ 0.95, more preferably 0.1 ≤ y ≤ 0.9, even more preferably 0.2 ≤ y ≤ 0.85, even more preferably 0.25 ≤ y ≤ 0.8, even more preferably 0.3 ≤ y ≤ 0.75, and most preferably 0.6 ≤ y ≤ 0.7. In a very preferred embodiment, y is approximately 0.65.

[0040] A preferred embodiment is a manufacturing method according to the present invention, wherein the solid sulfide electrolyte is represented by formula (II): Li 10.35 X 1.35 P 1.65 S 12 (II).

[0041] A preferred embodiment is a manufacturing method according to the present invention, wherein the solid sulfide electrolyte is represented by formula (III): Li 10.35 Si 1.35 P 1.65 S 12 (III).

[0042] A preferred embodiment is a manufacturing method according to the present invention, wherein the molar ratio of Li:X:P:S is (10-11):(1-2):(1-2):(11-13), preferably (10.2-10.7):(1.1-1.9):(1.1-1.9):(11.5-12.5), more preferably (10.3-10.4):(1.3-1.4):(1.6-1.7):(11.9-12.1), and most preferably about 10.35:1.35:1.65:12.

[0043] A preferred embodiment is a manufacturing method according to the present invention, wherein a set of precursors is mixed at a mixing speed of 1 to 1500 rpm, more preferably 100 to 1000 rpm, and most preferably 300 to 750 rpm. According to a very preferred embodiment, the solid electrolyte precursor mixture is mixed at a mixing speed of 300 to 700 rpm, preferably 350 to 650 rpm, and more preferably 400 to 600 rpm.

[0044] A preferred embodiment is the present manufacturing method according to the present invention, wherein the mixing is carried out for a mixing time of at least 1 minute, preferably at least 30 minutes, more preferably at least 1 hour, even more preferably at least 2 hours, even more preferably at least 5 hours, and most preferably at least 10 hours. A preferred embodiment is the present manufacturing method according to the present invention, wherein the mixing is carried out for less than 72 hours, preferably less than 60 hours, more preferably less than 50 hours, even more preferably less than 36 hours, even more preferably less than 30 hours, and even more preferably less than 20 hours. A preferred embodiment is the present manufacturing method by mixing solid electrolyte precursors, wherein the mixing of the set of precursors is carried out for a mixing time of 1 to 72 hours, preferably 2 to 50 hours, and most preferably 5 to 20 hours.

[0045] According to a very preferred embodiment of the present invention, the mixing of the set of precursors is A mixing speed of -1 to 1500 rpm, preferably 100 to 1000 rpm, more preferably 300 to 750 rpm, and The mixing is carried out with a mixing time of -1 to 72 hours, preferably 2 to 50 hours, and more preferably 5 to 20 hours.

[0046] A preferred embodiment is a manufacturing method according to the present invention, wherein the mixing of the set of precursors is carried out at a temperature of at least 5°C, preferably at least 10°C, and more preferably at least 15°C. A preferred embodiment is the same manufacturing method according to the present invention, wherein the mixing is carried out at a temperature of less than 50°C, preferably less than 40°C, and more preferably less than 30°C.

[0047] A preferred embodiment is a manufacturing method according to the present invention, wherein the mixing is carried out at a temperature of 5 to 50°C, preferably 10 to 40°C, and more preferably 15 to 30°C.

[0048] As those skilled in the art will understand in certain embodiments, the mixing of the set of precursors is equivalent to grinding, mechanical grinding, ball mill grinding, pulverizing, or dry grinding of the set of precursors.

[0049] A preferred embodiment is a manufacturing method according to the present invention, wherein the mixing of a set of precursors is carried out using a mixing means, and mechanical stress is applied to the set of precursors to form a solid electrolyte mixture. As used in this disclosure, the term “applying mechanical stress” means mechanically applying shear stress, impact force, or similar. Examples of mixing means include grinders such as planetary ball mills, vibratory mills, and rolling mills, as well as kneaders. A suitable example of a mixing means, though not limiting to the present invention, is the planetary ball mill Retsch PM 100.

[0050] In a more preferred embodiment, the mixing of the precursor set is carried out by adding one or more ceramic or zirconia balls, preferably zirconia balls, to the precursor set to obtain a solid electrolyte. As will be understood by those skilled in the art, the amount and size of the ceramic or zirconia balls are varied in consideration of the total solid amount of the solid electrolyte precursor. For example, without limiting the present invention, 16 zirconia balls in a 250 mL zirconia ball milling jar with a diameter of 20 mm can be used with a ball:powder ratio of 30:1 (g / g). As will be understood by those skilled in the art, these ceramic or zirconia balls are removed from the solid electrolyte mixture before heat treatment.

[0051] In a very preferred embodiment, as will be understood by those skilled in the art, the mixing of the set of precursors is carried out by dry mixing of the set of precursors, where dry mixing means that no additional liquid is added to the set of precursors in order to obtain a solid electrolyte mixture.

[0052] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is carried out at a temperature of at least 100°C, preferably at least 200°C, more preferably at least 300°C, more preferably at least 400°C, even more preferably at least 450°C, and most preferably at least 500°C.

[0053] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is carried out at a temperature of less than 1000°C, preferably less than 900°C, more preferably less than 800°C, even more preferably less than 700°C, even more preferably less than 650°C, and most preferably less than 600°C.

[0054] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is carried out at a temperature of 100 to 1000°C, preferably 300 to 700°C, and more preferably 450 to 650°C. In a very preferred embodiment, the heat treatment is carried out at a temperature of 500 to 600°C, preferably 525 to 575°C, and most preferably about 550°C.

[0055] A preferred embodiment is a manufacturing method according to the invention, wherein the heat treatment is carried out in an inert atmosphere, preferably in an argon atmosphere, or in an atmosphere containing hydrogen sulfide gas, preferably in an atmosphere consisting of hydrogen sulfide gas.

[0056] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is carried out at a pressure of at least 1 MPa, preferably at least 50 MPa, more preferably at least 100 MPa, even more preferably at least 175 MPa, and most preferably at least 250 MPa. A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is carried out at a pressure of less than 1000 MPa, preferably less than 850 MPa, more preferably less than 700 MPa, even more preferably less than 600 MPa, and most preferably less than 500 MPa. A preferred embodiment is the same manufacturing method according to the present invention, wherein the heat treatment is carried out at a pressure of 100 to 700 Pa, preferably 250 to 500 Pa, and more preferably 300 to 400 Pa. In a very preferred embodiment, the heat treatment is carried out at a pressure of 325 to 90 MPa, preferably 350 to 380 MPa, and most preferably about 375 MPa.

[0057] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is at least 1 minute, preferably at least 30 minutes, more preferably at least 1 hour, even more preferably at least 1.5 hours, and most preferably at least 2 hours. A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture is less than 48 hours, preferably less than 24 hours, more preferably less than 18 hours, even more preferably less than 10 hours, and even more preferably less than 5 hours. A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment is 0.5 hours to 24 hours, preferably 1 hour to 12 hours, and more preferably 1.5 hours to 5 hours.

[0058] A preferred embodiment is a manufacturing method according to the present invention, - The heat treatment is carried out at a temperature of 100 to 1000°C, preferably 300 to 700°C, most preferably 450 to 650°C. - The manufacturing method is carried out at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, and more preferably 300 to 400 MPa.

[0059] A particularly very preferred embodiment is the manufacturing method according to the present invention, - The heat treatment is carried out at a temperature of 500-600°C, preferably 525-575°C, most preferably about 550°C. - The manufacturing method is characterized by carrying out heat treatment at a pressure of 300 to 400 MPa, preferably 350 to 390 MPa, and most preferably about 375 MPa.

[0060] As will be understood by those skilled in the art, the heat treatment of a solid electrolyte mixture at a defined temperature and a defined pressure is called hot pressing of the solid electrolyte mixture, thereby yielding a solid sulfide electrolyte represented by formula (I), preferably a solid sulfide electrolyte represented by formula (II), and most preferably a solid sulfide electrolyte represented by formula (III). Furthermore, the heat treatment of a solid electrolyte mixture at a defined temperature and a defined pressure is carried out by applying the defined heat and defined pressure simultaneously.

[0061] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture is carried out by means for applying heat and pressure, for example, by hot pressing and / or spark plasma sintering, preferably by hot pressing. Not limiting the present invention, suitable examples of means for applying heat and pressure include hot pressing, for example, a Horijne hot pressing apparatus.

[0062] As will be understood by those skilled in the art, it is preferable to place the solid electrolyte mixture obtained in step ii) in a mold, a tungsten carbide mold, and then place it in a means for applying heat and pressure, a hot press. The means for applying heat and pressure is placed under vacuum, preferably below 1 bar, more preferably below 0.5 bar, most preferably below 0.2 bar, for example, below about 0.1 bar. Then, the heat treatment process as defined in the present invention is applied to the mold containing the solid electrolyte mixture obtained in step ii).

[0063] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture in step iii) comprises the following two steps: iii-a) A step of raising the temperature of the solid electrolyte mixture to a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, at a heating rate of at least 10°C / min, preferably at least 15°C / min, more preferably at least 18°C / min, and iii-b) A step of heat-treating a solid electrolyte mixture at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, and at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa.

[0064] A preferred embodiment is the manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture in step iii) is a manufacturing method comprising the following two steps: iii-a) A step of raising the temperature of the solid electrolyte mixture to a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, at a heating rate of up to 50°C / min, preferably up to 30°C / min, more preferably up to 25°C / min, and iii-b) A step of heat-treating a solid electrolyte mixture at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, and at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa.

[0065] A preferred embodiment is the manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture in step iii) is a method comprising the following two steps: iii-a) A step of raising the temperature of the solid electrolyte mixture to a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, at a heating rate of 10 to 50°C / min, preferably 15 to 30°C / min, more preferably 18 to 25°C / min, and iii-b) A step of heat-treating a solid electrolyte mixture at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, and at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa.

[0066] A preferred embodiment is a manufacturing method according to the present invention, wherein the heat treatment of the solid electrolyte mixture in step iii) is a method comprising the following two steps: iii-a) A step of raising the temperature of the solid electrolyte mixture to 500-600°C, preferably 525-575°C, more preferably about 550°C, at a heating rate of 10-50°C / min, preferably 15-30°C / min, more preferably about 18-25°C / min, and iii-b) A step of performing heat treatment at a temperature of 500 to 600°C, preferably 525 to 575°C, most preferably about 550°C, and at a pressure of 300 to 400 MPa, preferably 350 to 390 MPa, most preferably about 375 MPa.

[0067] The inventors believe that by applying the heating rate defined above, a solid sulfide electrolyte can be obtained with high purity.

[0068] A preferred embodiment is a manufacturing method according to the present invention, - The heat treatment is carried out at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C. - The manufacturing method involves performing a heat treatment for 0.5 to 24 hours, preferably 1 to 12 hours, and more preferably 1.5 to 5 hours.

[0069] A preferred embodiment is a manufacturing method of the present invention, - The heat treatment is carried out at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa. - The manufacturing method involves performing a heat treatment for 0.5 to 24 hours, preferably 1 to 12 hours, and more preferably 1.5 to 5 hours.

[0070] A preferred embodiment is the manufacturing method described in the present invention, - The heat treatment is carried out at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C. - The heat treatment is carried out at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa. - The manufacturing method involves performing a heat treatment for 0.5 to 24 hours, preferably 1 to 12 hours, and more preferably 1.5 to 5 hours.

[0071] In certain preferred embodiments of the present invention, the manufacturing method includes a further step iv) cooling the sulfide solid electrolyte to a temperature of 10-40°C, preferably 10-30°C, more preferably 15-25°C by applying a cooling rate of at least 10°C / min, preferably at least 15°C / min, more preferably at least 18°C / min. In certain preferred embodiments of the method of the present invention, the sulfide solid electrolyte is cooled to a temperature of 10-40°C, preferably 10-30°C, more preferably 15-25°C by applying a cooling rate of up to 50°C / min, preferably up to 40°C / min, more preferably up to 30°C / min. In certain preferred embodiments of the method of the present invention, the sulfide solid electrolyte is cooled to a temperature of 10-40°C, preferably 10-30°C, more preferably 15-25°C by applying a cooling rate of preferably 10-50°C / min, preferably 15-30°C / min, more preferably 18-25°C / min, most preferably about 20°C / min. As will be understood by those skilled in the art, the sulfide solid electrolyte is cooled to room temperature as defined above. In other words, in certain preferred embodiments, the manufacturing method of the present invention is: I) A step of preparing the set of precursors defined above, II) A step of mixing the set of precursors defined above, III) A step of heat-treating the solid electrolyte mixture defined above, Iv) The step of cooling the solid sulfide electrolyte obtained in step iii) to a temperature preferably of 10 to 40°C, preferably 10 to 30°C, more preferably 15 to 25°C, by applying a cooling rate preferably of 10 to 50°C / min, preferably 15 to 30°C / min, more preferably 18 to 25°C / min, and most preferably about 20°C / min.

[0072] The inventors believe that by applying the cooling rate defined above, a solid sulfide electrolyte can be obtained with high purity.

[0073] In a particular, highly preferred embodiment, the manufacturing method of the present invention is: I) A step of preparing the set of precursors defined above, II) A step of mixing the set of precursors defined above, III) A step of heat-treating the solid electrolyte mixture defined above, preferably comprising raising the temperature as defined in step iii-a), followed by the heat treatment as defined in step iii-b), iv) The process includes the step of cooling the solid sulfide electrolyte as defined above.

[0074] In one preferred embodiment of the manufacturing method of the present invention, the manufacturing method yields a solid sulfide electrolyte that, based on XRD measurements, substantially does not contain a phase formed from Li2S, P2S5, X=Si, Ge, Sn or a combination thereof, XS2, and / or Li3PS4, and in which case the peak intensity of Li2S, P2S5, XS2, and / or Li3PS4 is less than 30%, preferably less than 25%, more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5% of the peak intensity of the solid sulfide electrolyte represented by formula (I), preferably the solid sulfide electrolyte represented by formula (II), more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5%. According to the preferred embodiment, the solid sulfide electrolyte has a purity of at least 70%, preferably at least 75%, more preferably at least 80%, even more preferably at least 90%, and most preferably at least 95%, as measured by XRD.

[0075] In a preferred embodiment of the method of the present invention, the solid sulfide electrolyte has an XRD pattern using CuKα radiation at approximately 2θ = 20.18±0.50°, 20.44±0.50°, 26.96±0.50°, and 29.58±0.50°.

[0076] solid sulfide electrolyte A second aspect of the present invention provides a solid sulfide electrolyte that can be obtained by the present invention.

[0077] As will be understood by those skilled in the art, all embodiments relating to the method for producing a solid sulfide electrolyte according to the present invention are applicable mutatis mutandis to the solid sulfide electrolyte that can be obtained by the production method according to the present invention. In particular, one more preferred embodiment is a solid sulfide electrolyte that can be obtained by the production method according to the present invention, the solid sulfide electrolyte being represented by formula (I), Li 11-y X 2-y P 1+y S 12 (I) In the formula, 0≦y<2, preferably 0≦y<1, more preferably 0.05≦y≦0.95, even more preferably 0.1≦y≦0.9, even more preferably 0.2≦y≦0.85, even more preferably 0.25≦y≦0.8, even more preferably 0.3≦y≦0.75, and most preferably 0.6≦y≦0.7. In a very preferred embodiment, y is about 0.65, In the formula, X is Si, Ge, Sn, or a combination thereof, preferably X is Si.

[0078] A very preferred embodiment is a solid sulfide electrolyte that can be obtained by the manufacturing method according to the present invention, the solid sulfide electrolyte that can be obtained by the manufacturing method according to the present invention is represented by formula (II): Li 10.35 X 1.35 P 1.65 S 12 (II).

[0079] A very preferred embodiment is a solid sulfide electrolyte that can be obtained by the manufacturing method according to the present invention, which is represented by formula (III): Li 10.35 Si 1.35 P 1.65 S 12 (III).

[0080] A preferred embodiment is a solid sulfide electrolyte that can be obtained by a manufacturing method according to the present invention, which, based on XRD measurements, substantially does not contain a phase formed of Li2S, P2S5, X=Si, Ge, Sn or a combination thereof, XS2, and / or Li3PS4, and the peak intensity of Li2S, P2S5, XS2, and / or Li3PS4 is less than 30%, preferably less than 25%, more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5% of the peak intensity of the solid sulfide electrolyte represented by formula (I), preferably less than 25%, more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5%. According to the preferred embodiment, the solid sulfide electrolyte according to the present invention has a purity of at least 70%, preferably at least 75%, more preferably at least 80%, even more preferably at least 90%, and most preferably at least 95%, as measured by XRD.

[0081] A preferred embodiment is a solid sulfide electrolyte that can be obtained by the method according to the present invention, having XRD patterns of approximately 2θ = 20.18 ± 0.50°, 20.44 ± 0.50°, 26.96 ± 0.50°, and 29.58 ± 0.50° using CuKα radiation.

[0082] A third aspect of the present invention is to provide a solid sulfide electrolyte represented by formula (I): Li 11-y X 2-y P 1+y S 12 (I) In the formula, 0≦y<2, preferably 0≦y<1, more preferably 0.05≦y≦0.95, even more preferably 0.1≦y≦0.9, even more preferably 0.2≦y≦0.85, even more preferably 0.25≦y≦0.8, even more preferably 0.3≦y≦0.75, and most preferably 0.6≦y≦0.7. In a very preferred embodiment, y is about 0.65. In the formula, X is Si, Ge, Sn, or a combination thereof, preferably X is Si.

[0083] As will be understood by those skilled in the art, all embodiments relating to the method for producing a solid sulfide electrolyte according to the present invention, and all embodiments relating to the solid sulfide electrolyte obtained by the method for producing a solid sulfide electrolyte, are equally applicable to the solid sulfide electrolyte according to a third aspect of the present invention.

[0084] A very preferred embodiment is a solid sulfide electrolyte according to a third aspect of the present invention, which is represented by formula (II): Li 10.35 X 1.35 P 1.65 S 12 (II).

[0085] A very preferred embodiment is a solid sulfide electrolyte according to a third aspect of the present invention, which is represented by formula (III): Li 10.35 Si 1.35 P 1.65 S 12 (III).

[0086] A preferred embodiment is a solid sulfide electrolyte according to a third aspect of the present invention, which, based on XRD measurements, substantially does not contain a phase formed of Li2S, P2S5, X=Si, Ge, Sn or a combination thereof, XS2, and / or Li3PS4, and the peak intensity of Li2S, P2S5, XS2, and / or Li3PS4 is less than 30%, preferably less than 25%, more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5% of the peak intensity of the solid sulfide electrolyte represented by formula (I), preferably the solid sulfide electrolyte represented by formula (II), more preferably less than 20%, even more preferably less than 10%, and most preferably less than 5%. According to the preferred embodiment, the solid sulfide electrolyte according to the present invention has a purity of at least 70%, preferably at least 75%, more preferably at least 80%, even more preferably at least 90%, and most preferably at least 95%, as measured by XRD.

[0087] A preferred embodiment is a solid sulfide electrolyte that can be obtained by the method according to the present invention, having XRD patterns of approximately 2θ = 20.18 ± 0.50°, 20.44 ± 0.50°, 26.96 ± 0.50°, and 29.58 ± 0.50° using CuKα radiation.

[0088] battery A fourth aspect of the present invention is a battery comprising a negative electrode, a positive electrode, and a solid electrolyte layer, wherein at least one of the positive electrode, negative electrode, and solid electrolyte layer contains a solid sulfide electrolyte according to the present invention, such as a solid sulfide electrolyte according to a second aspect of the present invention and / or a solid sulfide electrolyte according to a third aspect of the invention. The solid sulfide electrolyte of the present invention can be used as a solid electrolyte layer in a solid lithium-ion battery or a solid lithium primary battery, or as a solid electrolyte mixed with an electrode mixture of a positive electrode or a negative electrode.

[0089] In a preferred embodiment, the battery is a solid-state battery, preferably a lithium solid-state battery.

[0090] use A fifth aspect of the present invention relates to the use of a solid sulfide electrolyte according to the present invention, such as a solid sulfide electrolyte according to the second aspect of the present invention and / or a solid sulfide electrolyte according to the third aspect of the present invention, in a battery, preferably a solid battery, more preferably a lithium solid battery.

[0091] A sixth aspect of the present invention relates to the use of a battery according to the present invention in one of the following: a portable computer, a tablet, a mobile phone, an energy storage system, an electric vehicle, or a hybrid electric vehicle, preferably in an electric vehicle or a hybrid electric vehicle. The present invention is further illustrated in the following embodiments. [Examples]

[0092] Explanation of the test method XRD analysis Powder X-ray diffraction patterns were measured using a Bruker D8 diffractometer equipped with either θ-θ configuration Cu(K1-K2) or Mo(K1-K2) radiation. An airtight sample holder with a Be window was used for the measurements. The patterns were measured at 25°C with a step size of 0.02°, between 2θ = 10° and 50°.

[0093] Examples Ball mill grinding and synthesis All synthesis and sample processing were performed in an Ar-filled glove box with O2 and H2O levels <0.1 ppm. The stoichiometric ratios of the reagents Li2S (Albemarle, 99.9%), P2S5 (Sigma Aldrich, 99%), and SiS2 (LTS US, 99%) were weighed to obtain 15 g batches of precursor. The precursor was transferred to a Restch PM 100 using a 250 mL zirconia ball milling jar with 16 zirconia balls with a diameter of 20 mm (ball:powder ratio was 30:1 (g / g)). The precursor was first ground at 100 rpm for 60 minutes to homogenize the mixture, followed by ball milling at 550 rpm for a total duration of 12 hours. Each cycle consisted of 5 minutes of milling and 5 minutes of rest. The ball-milled powder was then subjected to three different heat treatments.

[0094] Heat treatment synthesis i) Conventional heat treatment (comparative example) The ball-milled powder was uniaxially pressed into 13 mm pellets, placed in a pre-dried quartz tube, then sealed in an Ar environment and placed in a furnace (Nabertherm) for annealing. The furnace temperature was slowly increased to 550-600°C at a ramp rate of 5°C / min and held for 6-72 hours, then allowed to cool naturally to room temperature. The reacted pellets were then ground using a mortar and pestle and subjected to XRD analysis (see Figure 1). Clearly, only Li3PS4 was observed as the dominant phase in all calcination pathways (48 hours at 600°C, 72 hours at 550°C, 6 hours at 575°C, or 18 hours at 575°C), Li 10.35 Si 1.35 P 1.65 S 12 No phase was observed.

[0095] ii) Quenching following conventional heat treatment (comparative example) The ball-milled powder was uniaxially pressed into 13 mm pellets, placed in a pre-dried quartz tube, then sealed in an Ar environment and placed in a furnace (Nabertherm) for annealing. The furnace temperature was slowly increased to 575°C at a ramp rate of 5°C / min and held for 6 hours, then quenched to room temperature (25°C) by removing the quartz tube from the oven. The reaction pellets were then ground using a mortar and pestle and subjected to XRD analysis (see Figure 2). Quenching of the calcined mixture was performed using Li 10.35 Si 1.35 P 1.65 S 12 It promotes phase formation, but the main phases are Li3PS4 and Li 10.35 Si 1.35 P 1.65 S 12 A mixture with the phase is still obtained.

[0096] iii) Heat treatment is performed by hot pressing. The ball-milled powder was uniaxially pressed into 26 mm pellets in a WC (tungsten carbide) mold, and the mold was placed in a hot press (Stigene) and set under vacuum (0.1 bar). The temperature was increased to 550°C at a ramp rate of 20°C / min under a pressure of 375 MPa and held for 3 hours, then cooled to room temperature at a ramp rate of 20°C / min. The reacted pellets were then ground using a mortar and pestle and subjected to XRD analysis (see Figure 3): pure Li 10.35 Si 1.35 P 1.65 S 12 The phase was obtained without any by-products such as Li3PS4.

Claims

1. A method for producing a solid sulfide electrolyte, comprising: i) A step of preparing a set of precursors including Li, X, P, and S, ii) A step of mixing the set of precursors to obtain a solid electrolyte mixture, iii) The process includes a step of heat-treating the solid electrolyte mixture at a temperature of at least 100°C and a pressure of 1 to 1000 MPa to obtain a solid sulfide electrolyte, The solid sulfide electrolyte is represented by formula (I): Li １１－ｙ X ２－ｙ P １＋ｙ S １２ (I) In the equation, 0 ≤ y < 1, A method for producing a solid sulfide electrolyte, wherein X is Si, Ge, Sn, or a combination thereof.

2. A method for producing a solid sulfide electrolyte according to claim 1, wherein the set of precursors comprises one or more selected from the group consisting of metallic lithium or elemental lithium, lithium sulfide (Li2S), lithium oxide (Li2O), lithium carbonate (Li2CO3), lithium hydrosulfide (LiHS), lithium trithiocarbonate (Li2CS3), lithium polysulfide (Li2Sx, where x = 2 to 100), phosphorus sulfides such as phosphorus trisulfide (P2S3) and phosphorus pentasulfide (P2S5), sodium phosphate (Na3PO4), phosphorus elemental substances such as PSZ3 and P4 where Z is an element selected from F, Cl, Br, and I, lithium phosphate sulfide (Li3PS4), and X-containing compounds, preferably the set of precursors comprises one or more selected from the group consisting of lithium sulfide, phosphorus sulfide, and X-containing compounds.

3. The X-containing compound is element X or XS2, preferably XS ２ A method for producing a solid sulfide electrolyte according to claim 1 or 2.

4. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 3, wherein X = Si.

5. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 4, wherein 0.1 ≤ y ≤ 0.90, preferably 0.3 ≤ y ≤ 0.8, and more preferably 0.6 ≤ y ≤ 0.

7.

6. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 5, wherein the solid sulfide electrolyte is represented by formula (II): Li １０．３５ 8 １．３５ P １．６５ ﳳ １２ (99)。

7. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 6, wherein the solid sulfide electrolyte is represented by formula (III): Li １０．３５ Si １．３５ P １．６５ S １２ (III).

8. The mixing of the aforementioned set of precursors A mixing speed of -1 to 1500 rpm, preferably 100 to 1000 rpm, more preferably 300 to 750 rpm, and A method for producing a solid sulfide electrolyte according to any one of claims 1 to 7, comprising carrying out a mixing time of -1 to 72 hours, preferably 2 to 50 hours, more preferably 5 to 20 hours.

9. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 8, wherein the heat treatment is carried out at a temperature of 100 to 1000°C, preferably 300 to 700°C, and more preferably 450 to 650°C.

10. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 9, wherein the heat treatment is carried out at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, and more preferably 300 to 400 MPa.

11. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 10, wherein the heat treatment is 30 minutes to 24 hours, preferably 1 hour to 12 hours, and more preferably 1.5 hours to 5 hours.

12. The heat treatment of the solid electrolyte mixture in step iii) iii-a) A step of raising the temperature of the solid electrolyte mixture to 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, at a heating rate of 10 to 50°C / min, preferably 15 to 30°C / min, more preferably 18 to 25°C / min, iii-b) A method for producing a solid sulfide electrolyte according to any one of claims 1 to 11, comprising the step of heat-treating a solid electrolyte mixture at a temperature of 100 to 1000°C, preferably 300 to 700°C, more preferably 450 to 650°C, and at a pressure of 100 to 700 MPa, preferably 250 to 500 MPa, more preferably 300 to 400 MPa.

13. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 12, further comprising step iv) cooling the sulfide solid electrolyte to a temperature of 10 to 40°C, preferably 10 to 30°C, more preferably 15 to 25°C, preferably at a cooling rate of 10 to 50°C / min, preferably 15 to 30°C / min, more preferably 18 to 25°C / min, most preferably at a cooling rate of about 20°C / min.

14. A method for producing a solid sulfide electrolyte according to any one of claims 1 to 13, wherein the solid sulfide electrolyte has a purity of at least 95% when measured by XRD.

15. A solid sulfide electrolyte that can be obtained by the method described in any one of claims 1 to 14.

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