Heterovalent valence substituted argyrodite solid electrolytes

Abstract

This invention relates to heterovalent substituted argyrodite-type solid electrolytes. These solid electrolytes exhibit increased ionic conductivity.

Description

[Technical Field]

[0001] The present invention relates to a heterovalent substituted argyrodite-type solid electrolyte, a method for producing the solid electrolyte, and a battery containing the solid electrolyte. [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. Recently, solid-state batteries, which contain solid electrolytes instead of liquid electrolytes, have been developed to improve the safety aspects of lithium-ion batteries and have attracted much attention. For example, solid electrolytes are generally safer than liquid electrolytes due to their non-flammable or flame-retardant properties.

[0004] The solid electrolyte may include 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.

[0005] Minafra et al (J. Mater. Chem. A 2018, 6, 645-651) 6.125 P 0.875 Si 0.125 S5Br and Li 6.35 P 0.65 Si 0.35 General formulas for Li such as S5Br, where 0 ≤ x ≤ 0.5 6+x P1-x Si x Describes the synthesis of a solid electrolyte having S5Br.

[0006] Strauss et al (Inorg. Chem. 2020, 59, 12954-12959) describes the synthesis of Li7GeS5Br having an alluaudite structure.

[0007] An object of the present invention is to provide a hetero-valence substituted alluaudite type solid electrolyte.

[0008] A further object of the present invention is to provide a method for manufacturing the solid electrolyte.

[0009] A further object of the present invention is to provide a battery including the solid electrolyte.

Summary of the Invention

[0010] In a first aspect, the object of the present invention is achieved by providing a solid electrolyte having a composition according to formula (I):

[0011] Li 7-a YS 5-a X 1+a (I)

[0012] where -1.0 ≤ a ≤ 1.0, Y is selected from the group consisting of Si, Ge, and Ti, X is selected from the group consisting of F, Cl, Br, I, and any combination thereof.

[0013] A very preferred embodiment is the solid electrolyte of the present invention, provided that when Y = Ge and a = 0, X ≠ Br. [[ID=!50]]

[0014] In certain preferred embodiments, the solid electrolyte is according to the present invention and has a composition according to formula (II).

[0015] Li 7-b YS5-b ZQ b (II)

[0016] In the formula, 0 <b≦1.0であり、 Y is selected from the group consisting of Si, Ge, and Ti. Z is selected from the group consisting of F, Cl, Br, and I. Q is selected from the group consisting of F, Cl, Br, and I, and Z and Q are not the same halogen.

[0017] To our surprise, the inventors found that the composition of the heterovalent substituted argyrodite-type solid electrolyte was 2 mS.cm, as shown in the attached examples. -1 We found that this shows an increase in ionic conductivity up to a certain point.

[0018] While we do not wish to be bound by any theory, the inventors believe that heterovalence substitution of P with Si, Ge, or Ti leads to expansion of the unit cell and the inclusion of additional lithium cations within the structure. Furthermore, halide substitution is X - / S 2- This leads to increased site damage. Therefore, by altering the structure, not only is the lithium content increased, but the ionic interactions are also increased, leading to an increase in ionic conductivity as shown in the attached examples. Furthermore, these observations support two indicators: E hull (Energy on the outer shell) and E mig This was supported by computational modeling that focused on predicting the lithium diffusion rate into the argyrodite structure based on (transfer energy barrier). hull This identifies the stability of specific argyrodite compounds, while E mig This is a predictor of ionic conductivity.

[0019] In a further embodiment, the present invention provides a method for producing the solid electrolyte.

[0020] In a further embodiment, the present invention provides a battery comprising a solid electrolyte according to the present invention. [Brief explanation of the drawing]

[0021] [Figure 1] These are the X-ray diffraction patterns of Li7SiS5I, Li7SiS5Br, and Li7SiS5Cl recorded at 298K in a dome-shaped, airtight specimen holder made by Bruker. [Figure 2] These are the X-ray diffraction patterns of Li7.5SiS4.5I0.5 and Li7SiS5I recorded at 298K in a dome-shaped, airtight specimen holder made by Bruker. [Figure 3] X-ray diffraction patterns of Li6.5SiS4.5Br0.5I and Li6.5SiS4.5BrI0.5 recorded at 298K in a dome-shaped, airtight specimen holder made by Bruker. [Modes for carrying out the invention]

[0022] 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. Conversely, the present invention includes numerous alternatives, variations, and equivalents, which will become apparent by considering the following detailed description and the accompanying drawings.

[0023] 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.”

[0024] As used herein, 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 solid electrolyte.

[0025] As used herein, the term “argyrodite crystal structure” refers to a crystal structure having a crystal structure or system similar to the naturally occurring Ag8GeS6 and Li7PS6 (argyrodites). The argyrodite crystal structure may be orthorhombic and may be described in the F-43m space group. In some embodiments, the argyrodite crystal structure can also be empirically measured by X-ray diffraction, for example, by observing diffraction peaks at 2θ = 15.5±1°, 18±1°, 26±1°, 30.5±1°, and 32±1° using CuKα wavelengths. X-ray diffraction (XRD) as referred herein refers to XRD experiments performed using a Bruker D8 diffractometer equipped with either θ-θ arranged Cu(Kα1-Kα2) radiation. It is preferable to use a Bruker hermetically sealed sample holder dome window (transparent to X-rays). Preferably, the patterns were measured with a step size of 0.02° at 2θ = 10° to 50°.

[0026] The ionic conductivity referred to herein, unless otherwise specified, refers to the ionic conductivity determined at 23°C. This was preferably determined on a cold-pressed sample in a 13 mm die at 375 MPa using a BioLogic CESH cell, and the spectrum was recorded using an MTZ 35 frequency response analyzer by applying a 50 mV AC perturbation in the frequency range of 7 MHz to 1 Hz. Preferably, the relative density of the pellet was 90–92%, and the thickness was approximately 2.5 mm. Preferably, nickel foil was pressed onto the surface of the pellet as an ion-blocking electrode. More preferably, the spectrum was measured at temperatures in the range of 23°C at 10°C intervals.

[0027] As used herein, the term “solid electrolyte” refers to 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, 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] solid electrolyte In a first aspect, the object of the present invention is achieved by providing a solid electrolyte having a composition according to formula (I):

[0029] Li 7-a YS 5-a X 1+a (I)

[0030] In the equation, -1.0 ≤ a ≤ 1.0, Y is selected from the group consisting of Si, Ge, and Ti, and X is selected from the group consisting of F, Cl, Br, I, and any combination thereof.

[0031] A very preferred embodiment is the solid electrolyte according to the present invention, where X≠Br when Y=Ge and a=0.

[0032] In certain highly preferred embodiments, the present invention provides a solid electrolyte, but the solid electrolyte does not conform to formula (I)'.

[0033] Li7GeS5X (I)'

[0034] In the formula, X is selected from the group consisting of F, Cl, Br, I, and any combination thereof.

[0035] In a preferred embodiment, the solid electrolyte is according to the present invention and has a range of -0.99 ≤ a ≤ 0.99, preferably -0.95 ≤ a ≤ 0.95, more preferably -0.75 ≤ a ≤ 0.75, and most preferably -0.5 ≤ a ≤ 0.5.

[0036] In a preferred embodiment, the solid electrolyte is according to the present invention, and a = -0.5, 0, or 0.5, more preferably a = 0.5.

[0037] In certain preferred embodiments, the solid electrolyte is as described by the present invention, where Y is Si, Ge, or Ti, preferably Y is Si or Ge, or preferably Y is Si or Ti, and more preferably Y is Si.

[0038] In certain preferred embodiments, the solid electrolyte is according to the present invention, where X is Cl, Br, I, or a combination thereof, preferably X is Br, I, or a combination thereof, and more preferably X is Br or I.

[0039] In certain preferred embodiments, the solid electrolyte is according to the present invention, where X is F, Cl, Br, or I, preferably X is Cl, Br, or I, more preferably X is Br or I, and most preferably X is I.

[0040] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which at least 50 mol% of X represents F, preferably at least 80 mol% of X represents F, and most preferably X represents F.

[0041] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which X represents F, Cl, Br, I, or a combination thereof, and at least 50 mol% of X represents F, preferably at least 80 mol% of X represents F.

[0042] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which at least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl, and most preferably X represents Cl.

[0043] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which X represents F, Cl, Br, I, or a combination thereof, and at least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl.

[0044] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, and most preferably X represents Br.

[0045] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which X represents F, Cl, Br, I, or a combination thereof, and at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br.

[0046] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which at least 50 mol% of X represents I, preferably at least 80 mol% of X represents I, and most preferably X represents I.

[0047] According to a preferred embodiment of the present invention, a solid electrolyte is provided in which X represents F, Cl, Br, I, or a combination thereof, and at least 50 mol% of X represents I, preferably at least 80 mol% of X represents I.

[0048] In certain preferred embodiments, the solid electrolyte is according to the present invention. Y is Si, • X is Cl and -0.5 ≤ a ≤ 0.5, preferably -0.5 ≤ a ≤ 0, more preferably a = 0 or 0.5.

[0049] In certain preferred embodiments, the solid electrolyte is according to the present invention. Y is Si, • X is Br and -0.5 ≤ a ≤ 0.5, preferably a = -0.5, 0 or 0.5, more preferably a = -0.5 or 0.5.

[0050] In certain preferred embodiments, the solid electrolyte is according to the present invention. Y is Si, • X is I, and -0.5 ≤ a ≤ 0.5, preferably a = -0.5, 0 or 0.5, more preferably a = 0.5.

[0051] In a more preferred embodiment, the solid electrolyte is according to the present invention, and the solid electrolyte is given by formula (I)a to i.

[0052] [Table 1]

[0053] In a preferred embodiment, the solid electrolyte is a powder according to the present invention.

[0054] In a preferred embodiment, the solid electrolyte has an argyrodite-type crystal structure according to the present invention.

[0055] In a preferred embodiment, the solid electrolyte is according to the present invention, and the molar ratio of Li:Y:S:X is (5-8):(0.9-1.1):(4-6):(0.1-1.9), preferably (6.5-7.5):(0.99-1.01):(4.5-5.5):(0.5-1.5), more preferably (6.5):(1.0):(4.5):(1.5) or (7.0):(1.0):(5.0):(1.0) or (7.5):(1.0):(4.5):(0.5).

[0056] In a preferred embodiment, the solid electrolyte has a purity of at least 90%, preferably at least 95%, and more preferably at least 99%, as measured by XRD according to the present invention.

[0057] In a preferred embodiment, the solid electrolyte has an electrical conductivity of 0.1 to 5 mS / cm, preferably 0.5 to 3.5 mS / cm, and more preferably 1 to 2.5 mS / cm, according to the present invention.

[0058] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)a, preferably 0.5 to 1.5 mS / cm, more preferably 0.75 to 1.25 mS / cm, and most preferably about 1.1 mS / cm.

[0059] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)b, preferably 0.5 to 1.5 mS / cm, more preferably 0.75 to 1.25 mS / cm, and most preferably about 1.0 mS / cm.

[0060] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)d, preferably 1.0 to 2.0 mS / cm, more preferably 1.25 to 1.75 mS / cm, and most preferably about 1.5 mS / cm.

[0061] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)e, preferably 1.0 to 2.0 mS / cm, more preferably 1.25 to 1.75 mS / cm, and most preferably about 1.3 mS / cm.

[0062] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)f, preferably 1.0 to 2.0 mS / cm, more preferably 1.25 to 1.75 mS / cm, and most preferably about 1.5 mS / cm.

[0063] In certain preferred embodiments, the solid electrolyte of the present invention has an conductivity according to formula (I)g, preferably 1.0 to 2.5 mS / cm, more preferably 1.50 to 2.0 mS / cm, and most preferably about 1.7 mS / cm.

[0064] In certain preferred embodiments, the solid electrolyte of the present invention has a conductivity according to formula (I)h, preferably 1.0 to 2.5 mS / cm, more preferably 1.50 to 2.0 mS / cm, and most preferably about 1.7 mS / cm.

[0065] In certain preferred embodiments, the solid electrolyte of the present invention has a conductivity according to formula (I)i, preferably 1.0 to 2.5 mS / cm, more preferably 1.50 to 2.0 mS / cm, and most preferably about 1.8 mS / cm.

[0066] In certain preferred embodiments, the solid electrolyte is according to the present invention and has a composition according to formula (II).

[0067] Li 7-b YS 5-b ZQ b (II)

[0068] In the formula, 0 <b≦1.0であり、 Y is selected from the group consisting of Si, Ge, and Ti. Z is selected from the group consisting of F, Cl, Br, and I. Q is selected from the group consisting of F, Cl, Br, and I, and Z and Q are not the same halogen.

[0069] In a preferred embodiment, the solid electrolyte follows formula (II), where b is approximately 0.01 ≤ b ≤ 0.99, preferably 0.25 ≤ b ≤ 0.75, more preferably 0.4 ≤ b ≤ 0.6, and most preferably b is approximately 0.5.

[0070] In a preferred embodiment, the solid electrolyte follows formula (II), where Y is Si, Ge, or Ti, preferably Y is Si or Ge, or preferably Y is Si or Ti, and more preferably Y is Si.

[0071] In a preferred embodiment, the solid electrolyte follows formula (II), where Z is Cl, Br, or I, preferably Br or I.

[0072] In a preferred embodiment, the solid electrolyte follows formula (II), where Q is Cl, Br, or I, preferably Br or I.

[0073] In certain preferred embodiments, the solid electrolyte is provided according to formula (II), where, Y is Si, Z is Br, Q is I, and • 0.25 ≤ b ≤ 0.75, more preferably 0.4 ≤ b ≤ 0.6, and most preferably b is about 0.5.

[0074] In certain preferred embodiments, the solid electrolyte is provided according to formula (II), where, Y is Si, Z is I, Q is Br and • 0.25 ≤ b ≤ 0.75, more preferably 0.4 ≤ b ≤ 0.6, and most preferably b is about 0.5.

[0075] In a more preferred embodiment, the solid electrolyte is according to the present invention, and the solid electrolyte conforms to formula (II)a-b: [Table 2]

[0076] In a preferred embodiment, the solid electrolyte is of formula (II) having an argyrodite-type crystal structure.

[0077] In a preferred embodiment, the solid electrolyte follows formula (II), and the molar ratio of Li:Y:S:Z:Q is (5-8):(0.9-1.1):(4-6):(0.1-1.5):(0.1-1.5), preferably (6.5-7.5):(0.99-1.01):(4.5-5.5):(0.5-1.0):(0.5-1.0), more preferably (6.5):(1.0):(4.5):(0.5):(1.0) or (6.5):(1.0):(4.5):(1.0):(0.5) or (7.0):(1.0):(5.0):(0.5):(0.5).

[0078] In a preferred embodiment, the solid electrolyte conforms to formula (II) and has a purity of at least 90%, preferably at least 95%, and more preferably at least 99%, as measured by XRD.

[0079] In a preferred embodiment, the solid electrolyte has an conductivity of 0.1 to 5 mS / cm, preferably 0.5 to 3.5 mS / cm, and more preferably 1 to 2.5 mS / cm, according to formula (II).

[0080] In certain preferred embodiments, the solid electrolyte of the present invention has a conductivity according to formula (II)a, preferably 1.5 to 2.5 mS / cm, more preferably 2.0 to 2.5 mS / cm, and most preferably about 2.4 mS / cm.

[0081] In certain preferred embodiments, the solid electrolyte of the present invention has a conductivity according to formula (II)b, preferably 1.5 to 2.5 mS / cm, more preferably 2.0 to 2.5 mS / cm, and most preferably about 2.1 mS / cm.

[0082] Manufacturing method In a second aspect, the present invention provides a method for producing a solid electrolyte, the method being as follows: a) A step of providing a set of precursors comprising Li, S, Y, and X, b) A step of mixing a set of precursors to obtain a solid electrolyte mixture, c) A step of heat-treating a solid electrolyte mixture to obtain a solid electrolyte, This includes, where Y is selected from the group consisting of Si, Ge, and Ti. X is selected from the group consisting of F, Cl, Br, and I, preferably Cl, Br, or I, more preferably Br or I, and most preferably I.

[0083] In a preferred embodiment of this method, X consists of Z and Q. Here, Z is selected from the group consisting of F, Cl, Br, and I, preferably Cl, Br, or I, and more preferably Br or I. Q is selected from the group consisting of F, Cl, Br, and I, preferably Cl, Br, or I, more preferably Br or I, and Z and Q are not the same halogen.

[0084] In a very preferred embodiment, the present manufacturing method is according to the present invention, and the set of precursors includes one or more from the group consisting of Li2S, Si2S, Ge2S, and Ti2S, preferably Si2S, and one or more from the group consisting of LiI, LiBr, and LiCl.

[0085] In a very preferred embodiment, the manufacturing method is according to the present invention, and the solid electrolyte is a solid electrolyte according to the first aspect of the present invention, preferably a solid electrolyte according to formula (I), and / or a solid electrolyte according to formula (II), preferably a solid electrolyte according to formula (I)a to i and / or formula (I)a to b.

[0086] As will be understood by those skilled in the art, all embodiments relating to solid electrolytes according to the first aspect of the present invention are applicable mutatis mutandis to the present manufacturing method for producing solid electrolytes according to the present invention. For example, the various embodiments relating to formulas (I), (II), purity levels, and conductivity levels described herein in the context of solid electrolytes are equally applicable to the present manufacturing method for producing solid electrolytes according to the present invention.

[0087] In a preferred embodiment, the present manufacturing method is as described herein, and the mixing of the solid electrolyte precursor in step b) may include mixing, grinding, stirring, ball mill grinding, or a combination thereof.

[0088] In a preferred embodiment, the present invention provides a manufacturing method in which the set of precursors from step b) is mixed at a mixing speed of at least 100 rpm, preferably at least 300 rpm, and most preferably at least 400 rpm. In a preferred embodiment, the present invention provides a manufacturing method in which the set of precursors from step b) is mixed at a mixing speed of up to 1000 rpm, preferably up to 900 rpm, and most preferably up to 800 rpm. In a preferred embodiment, the present invention provides a manufacturing method in which the set of precursors from step b) is mixed at a mixing speed of 100 to 1000 rpm, preferably 300 to 900 rpm, and most preferably 400 to 800 rpm.

[0089] A particular preferred embodiment is the method according to the present invention, in which the mixing of the set of precursors in step b) is carried out by using a mixing means such as a ball mill, bead mill, homogenizer, screw mixer, horizontal mixer, pull shear mixer, jar mill, drum mill, or roller bench. In a more preferred embodiment, the mixing of the set of precursors in step b) is carried out by adding one or more ceramic or zirconia balls to the set of precursors. 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 content of the set of precursors. As will be understood by those skilled in the art, these ceramic or zirconia balls are removed before the heat treatment step c).

[0090] In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the precursor set in step b) is at least 1 hour, preferably at least 5 hours, and most preferably at least 10 hours. In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the precursor set in step b) is at most 70 hours, preferably at most 50 hours, and most preferably at most 30 hours. In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the precursor set in step b) is at least 1 to 70 hours, preferably at most 5 to 50 hours, and most preferably at most 10 to 30 hours.

[0091] In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the solid electrolyte precursor mixture in step b) is carried out at a temperature of at least 5°C, preferably at least 10°C, and more preferably at least 15°C. In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the solid electrolyte precursor mixture in step b) is carried out at a temperature of less than 50°C, preferably less than 40°C, and more preferably less than 30°C. In a preferred embodiment, the present manufacturing method is in accordance with the present invention, and the mixing of the solid electrolyte precursor mixture in step b) is carried out at a temperature of 5 to 50°C, preferably 10 to 40°C, and more preferably 15 to 30°C.

[0092] In certain preferred embodiments, the present manufacturing method is as described herein, and the mixing of the solid electrolyte precursor in step b) is • Mixing time of 1 to 70 hours, preferably 5 to 50 hours, most preferably 10 to 30 hours. The mixing is carried out at a mixing speed of 100 to 1000 rpm, preferably 300 to 900 rpm, and most preferably 400 to 800 rpm.

[0093] In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is carried out at a temperature of at least 100°C, preferably at least 150°C, more preferably at least 200°C, even more preferably at least 250°C, and most preferably at least 300°C. In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is carried out at a temperature of less than 1000°C, preferably less than 900°C, more preferably less than 750°C, even more preferably less than 600°C, and most preferably less than 500°C. In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is carried out at a temperature of 100 to 1000°C, preferably 200 to 750°C, and most preferably 250 to 450°C.

[0094] In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is at least 1 minute, preferably at least 0.5 hours, more preferably at least 1 hour, even more preferably at least 1.5 hours, and most preferably at least 2 hours. In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is less than 24 hours, preferably less than 12 hours, more preferably less than 10 hours, even more preferably less than 8 hours, and even more preferably less than 6 hours. In a preferred embodiment, the present manufacturing method is according to the present invention, and the heat treatment of the solid electrolyte mixture in step c) is 0.5 hours to 24 hours, preferably 1 hour to 12 hours, and more preferably 2 hours to 6 hours.

[0095] In certain preferred embodiments, the present manufacturing method is as described herein, and the heat treatment of the solid electrolyte mixture in step c) is • The process is carried out at a temperature of 100 to 1000°C, preferably 200 to 750°C, most preferably 250 to 450°C, and This process is carried out for 0.5 to 24 hours, preferably 1 to 12 hours, and most preferably 2 to 6 hours.

[0096] Product-by-process In a third aspect, the present invention relates to a solid electrolyte obtainable by a manufacturing method according to a second aspect of the present invention.

[0097] As will be understood by those skilled in the art, all embodiments relating to the solid electrolyte according to the first aspect of the present invention and / or the manufacturing method according to the second aspect of the present invention are applicable mutatis mutandis to solid electrolytes obtainable by the manufacturing method according to the present invention. For example, the various embodiments relating to formula (I), formula (II), purity level, and conductivity level described herein in the context of solid electrolytes are equally applicable to solid electrolytes obtainable by the manufacturing method of the solid electrolyte.

[0098] battery A fourth aspect of the present invention relates to 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 the solid electrolyte according to the present invention. The solid electrolyte of the present invention can be used as a solid electrolyte layer of 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.

[0099] In a preferred embodiment, the battery is a solid-state battery, preferably a lithium solid-state battery.

[0100] use A fifth aspect of the present invention relates to the use of a solid electrolyte according to the present invention in a battery, preferably a solid-state battery, most preferably a lithium solid-state battery.

[0101] 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 a vehicle or a hybrid electric vehicle.

[0102] The present invention is further illustrated in the following embodiments. [Examples]

[0103] Explanation of the test method Computation protocol The computational models are, respectively, E hull (Energy on the outer shell) and E mig Based on the (transfer energy barrier), we focus on predicting thermodynamic stability and the lithium diffusion rate into the argyrodite structure.

[0104] E hull E is an important indicator for determining the relative stability of a phase compared to other phases present in the multicomponent phase diagram of a combination element. For example, to determine the phase stability of an argyrodite compound, it is necessary to calculate the energies of all known phases in the Li-PS-Cl chemical space and construct the phase diagram. A standard calculation method is to construct a convex closure of the multicomponent phase diagram at 0K. Then, the energy of each phase is considered as 0 and "E" is used. hull The calculation is based on the energy of the convex closure called "E". Therefore, E hull A higher value indicates that the compound is higher, above the convex closure of the most stable phase, and has lower thermodynamic stability. This parameter is used to rank the most stable compounds and indicate the most likely to be synthesizable.

[0105] During charging and discharging, lithium ions jump from one stable site to another by overcoming energy barriers and traversing the potential energy landscape. The height of these energy barriers is calculated from the bond length (R) of the shape. A-X ) and its strength (s A-X It is estimated by the bond valence method relating to (A and X are the lithium ion and its adjacent atoms, respectively). The relationship is given by the following equation:

[0106] s A-X =exp[(R0-R A-X / b )]

[0107] In the equation, R0 and b are empirical bond valence (BO) parameters. This relationship gives their bond valences V(A) = Σx s A-X The sum of these is the ideal valence (oxidation state) of the lithium ion, V. ideal This allows mobile lithium ions to be located in an accessible position within the local structure of the electrolyte, closest to the target. The lowest energy pathway is the valence sum deviation |V (A) -V ideal(A) | is the path where is minimized and the corresponding energy barrier is the path where the lowest transfer energy barrier is required for lithium ions to diffuse in the electrolyte. Transfer energy barrier (E mig The lower the E, the higher the lithium ion diffusion rate, and therefore, the higher the ionic conductivity of the electrolyte. mig This is an index of ionic conductivity used to rank promising candidates. Transfer energy is evaluated using the code BOND_STR, distributed within the FullProf package of the CrysFML library.

[0108] Synthesis protocol 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%), SiS2 (LTS US, 99%), LiCl (Sigma Aldrich, 99.98%), and / or LiBr (Sigma Aldrich, 99%), and / or LiI (Sigma Aldrich, 99.9%) 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). The precursor was first milled at 100 rpm for 60 minutes to homogenize the mixture, followed by ball milling at 510 rpm for a total duration of 25 hours. Each cycle consisted of 5 minutes of milling followed by 5 minutes of rest, with the milling direction reversed for all cycles. At the end of the ball milling process, approximately 96% by weight of the material was recovered. The ball milled powder was placed in a dry quartz tube, then sealed under argon, and placed in a furnace (Nabertherm) for heat treatment. The furnace temperature was slowly increased to 300°C at a ramp rate of 2°C / min and held for 2 hours, then allowed to cool naturally to room temperature. The reacted powder was then ground using a mortar and pestle and stored in a glove box for further analysis.

[0109] X-ray diffraction Powder X-ray diffraction patterns were measured using a Bruker D8 diffractometer equipped with either θ-θ arranged Cu(Kα1-Kα2) radiation. A dome-type airtight sample holder was used for the measurements. The patterns were analyzed in steps of 0.02°, from 2θ = 10° to 50°. ° It was measured between these two points.

[0110] Measurement of ionic conductivity Approximately 500 mg of sample was cold-pressed uniaxially using a 13 mm die at 375 MPa. The relative density of the pellets was 90–92%, and the thickness was approximately 2.5 mm. AC impedance spectroscopy was performed on these pellets by mounting them in a pouch cell, and spectra were recorded using a Biologic analyzer by applying a 50 mV AC perturbation in the frequency range of 7 MHz to 1 Hz. The spectra were then analyzed using 23 ° Measurements were taken at C. AC impedance data was analyzed using Zview or RelaxIS software.

[0111] Examples Table 1 shows a series of solid electrolytes that conform to formula (I) hull and E mig This indicates. [Table 3] Table 1: E of CEX1-3, EX1-8, and EX11-20 hull and E mig .

[0112] Table 2 shows the overall equations for examples synthesized via a general synthesis protocol, along with their corresponding measured ionic conductivity E. hull and E mig It will be shown together with this.

[0113] [Table 4] Table 2: Stoichiometric formulas and ionic conductivity values ​​for CEX1, CEX42, EX1-10, and EX21.

[0114] Examples EX1-8 are examples of the present invention as described in the claims of the patent. Examples EX9 and EX10 are examples of the present invention as described in the claims of the patent.

[0115] na = Not applicable.

[0116] Profile matching of powder X-ray diffraction data suggests that the argyrodite structure is retained for samples EX2, 4, and 7 (Figure 1), EX6 and 7 (Figure 2), and EX9 and 10 (Figure 3), with no peaks corresponding to precursor or other impurity phases observed.

Claims

1. Solid electrolyte having the composition of formula (I): Li ７－ａ YS ５－ａ X １＋ａ (I) (In the formula, -1.0 ≤ a ≤ 1.0, Y is selected from the group consisting of Si, Ge, and Ti, and X is selected from the group consisting of F, Cl, Br, I, and any combination thereof, However, if Y = Ge and a = 0, then X ≠ Br.

2. The solid electrolyte according to claim 1, wherein -0.99 ≤ a ≤ 0.99, preferably -0.75 ≤ a ≤ 0.75, more preferably -0.5 ≤ a ≤ 0.5, and most preferably a = -0.5, 0, 0.

5.

3. The solid electrolyte according to claim 1 or 2, wherein Y is Si or Ge, preferably Si.

4. The solid electrolyte according to any one of claims 1 to 3, wherein X is F, Cl, Br, or I, preferably Cl, Br, or I, more preferably Br or I, and most preferably X is I.

5. A solid electrolyte according to any one of claims 1 to 4, having a composition according to formula (I) a to i. Table 1

6. A solid electrolyte according to any one of claims 1 to 5, having an ionic conductivity of 0.1 to 5 mS / cm, preferably 0.5 to 2.5 mS / cm, and more preferably 1 to 2 mS / cm.

7. A method for producing a solid electrolyte, preferably the solid electrolyte described in any one of claims 1 to 6, the following: a) A step of providing a set of precursors comprising Li, S, Y, and X, b) A step of mixing the set of precursors to obtain a solid electrolyte mixture, c) A step of heat-treating the solid electrolyte mixture to obtain a solid electrolyte, This includes, where Y is selected from the group consisting of Si, Ge, and Ti. A method of production in which X is selected from the group consisting of F, Cl, Br, and I and combinations thereof, preferably X is F, Cl, Br, or I, more preferably X is Cl, Br, or I, even more preferably X is Br or I, and most preferably X is I.

8. A battery comprising a negative electrode, a positive electrode, and a solid electrolyte layer, wherein at least one of the positive electrode, the negative electrode, and the solid electrolyte layer contains the solid electrolyte described in any one of claims 1 to 7.

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