Method for producing sulfide-based lithium-ion conductive solid electrolytes

Abstract

The present invention relates to a method for producing a solid material obtained by melt quenching a mixture comprising lithium sulfide and boron sulfide, thereby forming a glassy solid suitable for use as a lithium ion conducting electrolyte. The inventors have demonstrated that the method results in the production of sulfide-based lithium ion conducting solid electrolytes of improved quality, in particular sulfide-based lithium ion conducting solid electrolytes with reduced inclusion of foreign bodies such as air bubbles.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a solid material obtained by melting and rapidly cooling a mixture containing lithium sulfide and boron oxide, thereby forming a glassy solid suitable for use as a lithium ion conductive electrolyte. [Background technology]

[0002] The three main functional components of a lithium-ion battery are the anode, cathode, and electrolyte. While many variations exist, the anode of a conventional lithium-ion cell is typically made from carbon, the cathode from a transition metal oxide (particularly cobalt, nickel, and / or manganese oxides), and the electrolyte is typically a non-aqueous solvent containing a lithium salt. For example, a mixture of organic carbonates and lithium hexafluorophosphate is a well-known liquid electrolyte for lithium-ion batteries.

[0003] A major drawback of liquid electrolytes is that their composition, particularly the solvent, is flammable, posing a significant safety risk during normal operation, especially in the event of an accident. Another drawback, inherent to the liquid nature of electrolytes, is the increased risk of leakage and, in the event of spills or leaks, the risk of environmental contamination.

[0004] In recent years, efforts have been made to develop solid electrolytes that enable the provision of solid lithium-ion batteries. Such solid batteries significantly reduce EHS (environment, health, and safety) risks. New types of lithium-ion conductive solid electrolytes include Li2S-SiS2, Li2S-P2S5, or Li2 S- These are sulfide-based amorphous solids such as B2S3 (commonly referred to as glassy solids). In glassy solid electrolyte materials, the absence of crystalline pathways results in isotropic conductivity with virtually no grain boundary resistance. The absence of grain boundaries in glassy electrolyte materials also prevents the formation of dendritic crystals, because glassy amorphous limit chamber materials can be obtained as high-density, defect-free films by melt-quenching methods.

[0005] Early studies on Li2S-B2S3 compositions with molar ratios of 70:30 and 60:40 have shown that the ΔT at approximately 70°C and approximately 110°C, respectively, is significant. x The values ​​were reported (Zhang et al, Solid State Ionics 1990, 38, 217-224).

[0006] U.S. Patent No. 5,500,291 concerns a Li2S-SiS2-Li4SiO4 type sulfide-based lithium-ion conductive solid electrolyte.

[0007] International Publication No. 2020 / 254314(A1) describes a Li2S-B2S3 type sulfide-based lithium-ion conductive solid electrolyte obtained from a mixture further comprising P, Si, Ge, As, or Sb oxides in combination with lithium halides.

[0008] International publication no. 2016 / 089899(A1) envisions numerous glass systems (many of which are speculative or unsubstantiated).

[0009] A major challenge in the production of glassy solid electrolytes is the avoidance of impurities or contaminants in the glass. Ideally, the glass is a continuous, homogeneous amorphous bulk. However, in reality, glasses are typically characterized by irregular inclusions of deviating materials. This deviating material can be anything such as unwanted zones of crystallized material, unreacted precursors, impurities derived from the precursors, air bubbles, etc. The presence of inclusions is a problem for the post-treatment of the glass. This type of defect can act as a nucleating agent and favorably influence the crystallization of the material. The presence of defects induces a material that is no longer isotropic, which poses a problem for the protective behavior against dendritic crystals.

[0010] Therefore, there is a great need for a method for producing a high-quality sulfide-based lithium-ion conductive solid electrolyte with less inclusion of deviating materials such as unwanted zones of crystallized material, unreacted precursors, impurities derived from the precursors, air bubbles, etc.

[0011] An object of the present invention is to provide a method for producing a sulfide-based lithium-ion conductive solid electrolyte with improved quality, particularly a method for producing a sulfide-based lithium-ion conductive solid electrolyte with less inclusion of foreign substances such as air bubbles.

[0012] Another object of the present invention is to provide a method for producing a sulfide-based lithium-ion conductive solid electrolyte having improved reproducibility compared to the methods of the prior art.

Summary of the Invention

[0013] The inventors have found that one or more of the present invention can be achieved by a method for producing a sulfide-based lithium-ion conductive solid electrolyte, comprising melting and quenching a combination of Li2S; boron; sulfur; B2O3 and optionally LiX (wherein X represents F, Cl, Br, I, N3, SCN, CN, OCN, BF4, BH4 or a combination thereof, preferably X represents Cl, Br, I or a combination thereof). As shown in the accompanying examples, the resulting glassy solid is indeed observed to exhibit less inclusion of deviant materials, particularly fewer bubbles, compared to materials prepared using B2S3 instead of both boron and sulfur.

[0014] Embodiment 1 Therefore, in a first aspect of the present invention, a method for preparing a solid material, (i) The following precursors: Li2S; Both boron and sulfur; B2O3; and A step of providing LiX (wherein X represents F, Cl, Br, I, N3, SCN, CN, OCN, BF4, BH4 or a combination thereof, preferably X represents Cl, Br, I or a combination thereof) at an optional choice; (ii) A step of preparing a mixture containing the precursor provided in step (i); (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product; A method is provided which includes (iv) a step of rapidly cooling the molten material obtained in step (iii) to obtain a solid material.

[0015] Embodiment 2 In another aspect of the present invention, a solid material is provided which can be obtained by the method described herein (i.e., the method of Embodiment 1).

[0016] Embodiment 3 In another aspect of the present invention, a solid composition is provided which comprises a first solid material which is a solid material described herein (i.e., the solid material of Embodiment 2), and further comprises at least a second solid material which has a different composition from the first solid material.

[0017] Embodiment 4 In another aspect of the present invention, an electrochemical cell is provided comprising a solid material described herein (i.e., the solid material of Embodiment 2).

[0018] Embodiment 5 In another aspect of the present invention, the use of a solid material described herein (i.e., the solid material of Embodiment 2) or a solid composition described herein (i.e., the solid composition of Embodiment 3) as a solid electrolyte for an electrochemical cell is provided.

[0019] Embodiment 6 Another aspect of the present invention relates to a battery, more specifically a lithium-ion battery or a lithium-metal battery, comprising at least one electrochemical cell containing the solid material described herein (i.e., the solid material of Embodiment 2), for example, two or more electrochemical cells as described in Embodiment 4.

[0020] Embodiment 7 A further aspect of the present invention is a method for manufacturing or operating stationary applications such as automobiles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOSes, communication equipment, remote car locks, and energy storage devices for power plants, by using at least one battery or at least one electrochemical cell (i.e., the electrochemical cell described in Embodiment 4) comprising the solid materials described herein.

[0021] Embodiment 8 Further aspects of this disclosure involve the use of an electrochemical cell comprising the solid material of the present invention (i.e., the electrochemical cell described in Embodiment 4) in a motor vehicle, an electric motor-driven bicycle, a robot, an aircraft (e.g., an unmanned aerial vehicle including a drone), a ship, or a fixed energy storage device.

Mode for Carrying Out the Invention

[0022] In the following detailed description, preferred embodiments are described in detail to implement the present invention. The present invention is described with reference to these specific preferred embodiments, but it will be understood that the present invention is not limited to these preferred embodiments. However, in contrast, the present invention includes numerous alternatives, modifications, and equivalents as will become apparent in view of the following mode for carrying out the invention.

[0023] The thermal stability ΔT of glass x can be characterized as stability against crystallization, which is determined by the temperature difference between the crystallization start temperature (T x ) and the glass transition start temperature (T g ), that is, ΔT x = T x - T g . A larger ΔT x is generally related to improved glass-forming ability and improved glass stability during post-treatment.

[0024] The glass transition temperature (T g ) referred to in this specification refers to the start temperature of the glass transition determined by differential scanning calorimetry (DSC). This is preferably measured by constructing tangents to the baseline of the DSC curve before and after the glass transition, and determining the extrapolation start temperature by the intersection of these tangents, where the highest slope in the decrease of the DSC baseline essentially corresponds to the temperature occurring before the exothermic crystallization peak. DSC is preferably recorded using the following temperature profile: from 100 °C to 350 °C at a rate of 10 °C / min, and preferably, it is recorded with a 5 - 10 mg sample in a sealed aluminum pan. A suitable DSC apparatus is DSC 3500 Sirius.

[0025] The thermal stability (ΔT x ) referred to in this specification is the crystallization start temperature (T x) and the glass transition temperature (T) determined by DSC g It is the difference between ) and . In other words, ΔT x =T x -T g That is the case.

[0026] The ionic conductivity referred to herein refers to the ionic conductivity measured at 25°C by electrochemical impedance spectroscopy (EIS). Preferably, it is determined using an ion-blocking electrode on a hot-pressed sample densified at 350 MPa and 125°C for 5 minutes, after which the ionic conductivity is measured at 25°C under an operating pressure of 125 MPa. Preferably, an excitation voltage of 10 mV is applied in the frequency range of 7 MHz to 1 Hz, and the data are interpreted by equivalent circuit analysis. A suitable conductivity analyzer is a potentiostat with a frequency analyzer, such as those available from Biologic.

[0027] The electronic conductivity referred to herein refers to the electronic conductivity determined at 25°C. Preferably, it is determined using an ion-barring electrode on a hot-pressed sample densified at 350 MPa and 125°C for 5 minutes, after which the electronic conductivity is measured at 25°C under an operating pressure of 125 MPa. Preferably, the electronic conductivity was measured by stepwise constant-potential polarization at 0.2 V, 0.4 V, and 0.6 V for 20 minutes. A suitable conductivity analyzer is a potentiostat with a frequency analyzer, such as those available from Biologic.

[0028] Embodiment 1 In a first aspect of the present invention, a method for preparing a solid material, (i) The following precursors: Li2S; Both boron and sulfur; B2O3; and A step of providing LiX (wherein X represents F, Cl, Br, I, N3, SCN, CN, OCN, BF4, BH4, or a combination thereof) at any option; (ii) A step of preparing a mixture containing the precursor provided in step (i); (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product; A method is provided which includes (iv) a step of rapidly cooling the molten material obtained in step (iii) to obtain a solid material.

[0029] In a preferred embodiment of the present invention, no other precursors are used in this method. Therefore, the solid material obtained in step (iv) is preferably a melt-quench product of Li2S; boron; sulfur; B2O3 and optionally LiX (wherein X represents F, Cl, Br, I, N3, SCN, CN, OCN, BF4, BH4 or a combination thereof).

[0030] In a preferred embodiment of the present invention, a method for preparing a solid material is: (i) The following precursors: Li2S; Both boron and sulfur; B2O3; and A process of providing LiX (wherein X represents Cl, Br, I, or a combination thereof) at any option; (ii) A step of preparing a mixture containing the precursor provided in step (i); (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product; (iv) A step of rapidly cooling the molten material obtained in step (iii) to obtain a solid material.

[0031] In a preferred embodiment of the present invention, no other precursors are used in this method. Therefore, the solid material obtained in step (iv) is preferably a melt-quench product of Li2S; boron; sulfur; B2O3 and optionally LiX (wherein X represents Cl, Br, I, or a combination thereof).

[0032] The molar ratio of the precursor in the mixture before rapid cooling is preferably such that a composition following general formula (I) is obtained in step (ii). ((Li2S) x (B2S3) y (B2O3) z) A (LiX) B (I) (In the formula, x is in the range of 55 to 85, preferably 55 to 75, more preferably 60 to 70; y is in the range of 15 to 45, preferably 20 to 40, and more preferably 25 to 35; z is in the range of 0 to 15, preferably 0 to 10, more preferably 0 to 6; x+y+z=100; The ratio A:B is within the range of 60:40 to 100:0.

[0033] As can be understood by those skilled in the art, taking into account the definitions of A and B in formula (I), the ratio A:B relates to the molar ratio of the friction product obtained by mixing the precursors Li2S; boron; sulfur; B2O3 with respect to the precursor LiX in molar ratios x, y, and z. In practice, it is most convenient that all precursors are simply mixed according to the ratios specified by general formula (I) and then subjected to melt-quenching.

[0034] The provision of both boron and sulfur in step (i) should be interpreted as meaning the provision of elemental boron and elemental sulfur. Elemental boron and elemental sulfur may be provided in amorphous or crystalline form, and the specific allotropes used do not particularly limit the invention. Preferably, the method of the present invention is provided such that the mixture containing the precursor provided in step (i) does not contain boron sulfide (B2S3).

[0035] In a preferred embodiment of the present invention, x is in the range of 55 to 85, preferably 55 to 75, more preferably 60 to 70; y is in the range of 15 to 45, preferably 20 to 40, and more preferably 25 to 35; z is in the range of 1 to 15, preferably 1 to 10, more preferably 1 to 6; A method is provided for x+y+z=100.

[0036] In a preferred embodiment of the present invention, x is in the range of 62 to 68, preferably in the range of 63 to 67, and more preferably in the range of 64 to 66; y is in the range of 27 to 33, preferably in the range of 28 to 32, and more preferably in the range of 29 to 31; z is in the range of 1 to 8, preferably in the range of 3 to 7, and more preferably in the range of 4 to 6; A method is provided for x+y+z=100.

[0037] According to a very preferred embodiment of the present invention, x is approximately 65; y is approximately 30; A method is provided in which z is approximately 5.

[0038] Generally, the ratio A:B in the mixture before rapid cooling is preferably in the range of 75:25 to 98:2, more preferably 80:20 to 96:4, and more preferably 85:15 to 96:4. In some embodiments, the ratio A:B in the mixture before rapid cooling is in the range of 60:40 to 96:4, more preferably 70:30 to 96:4, and more preferably 75:25 to 96:4. In some embodiments, the ratio A:B in the mixture before rapid cooling is in the range of 60:40 to 94:6, more preferably 70:30 to 93:7, and more preferably 75:25 to 92:8.

[0039] Therefore, in some embodiments of the present invention, x is in the range of 62 to 68, preferably in the range of 63 to 67, and more preferably in the range of 64 to 66; y is in the range of 27 to 33, preferably in the range of 28 to 32, and more preferably in the range of 29 to 31; z is in the range of 1 to 8, preferably in the range of 3 to 7, and more preferably in the range of 4 to 6; x+y+z=100; A method is provided in which the ratio A:B in the mixture before rapid cooling is in the range of 85:25 to 98:2, preferably in the range of 80:20 to 96:4, and more preferably in the range of 85:15 to 96:4.

[0040] In some embodiments of the present invention, x is approximately 65; y is approximately 30; z is approximately 5; x+y+z=100; A method is provided in which the ratio A:B in the mixture before rapid cooling is in the range of 85:25 to 98:2, preferably in the range of 80:20 to 96:4, and more preferably in the range of 85:15 to 96:4.

[0041] According to a preferred embodiment of the present invention, a method is provided in which X represents Br, I, or a combination thereof. As shown in the appended examples, these materials have a thermal stability ΔT x Regarding this, it performs better than materials where X represents Cl.

[0042] According to a preferred embodiment of the present invention, a method 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. As shown in the attached examples, the material in which X represents Br has a thermal stability ΔT x Regarding this, it performs better than materials where X represents Cl.

[0043] A preferred embodiment of the present invention provides a method in which X represents Br, I, or a combination thereof, and at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br.

[0044] The solid material obtained in step (iv) of the method of the present invention is typically a glassy solid. In some embodiments, the solid material obtained in step (iv) is in the form of a monolithic glass, such as a melt-case monolithic glass. The glassy solid is preferably essentially free of a crystalline phase. This may mean that in some embodiments, the amount of the crystalline phase determined by X-ray diffraction is less than 5 volume%, preferably less than 2 volume%, and more preferably less than 1 volume% of the solid material. A phase is considered crystalline if its reflectance intensity is more than 10% higher than the background.

[0045] It has been found that the solid material obtained in step (iv) of the method of the present invention has a surprisingly high ionic conductivity. According to a preferred embodiment of the present invention, a method is provided in which the material obtained in step (iv) has an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.3 mS / cm, at 25°C. As shown in the appended examples, the inventors have surprisingly found that when at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, and most preferably X represents Br, the ionic conductivity at 25°C can be as high as about 2 mS / cm. Therefore, in some embodiments of the present invention, a method is provided in which the material obtained in step (iv) has an ionic conductivity of at least 1 mS / cm, preferably at least 1.1 mS / cm, and more preferably at least 1.2 mS / cm, at 25°C. In a particular embodiment of the present invention, X represents at least 50 mol% Br, preferably at least 80 mol% Br, and most preferably X represents Br; The solid material obtained in step (iv) has an ionic conductivity of at least 1 mS / cm, preferably at least 1.1 mS / cm, and more preferably at least 1.2 mS / cm at 25°C.

[0046] For example, in some embodiments of the method of the present invention, at least 80 mol% of X represents Br and the ionic conductivity of the solid material obtained in step (iv) is at least 1.1 mS / cm at 25°C, or X represents Br and the ionic conductivity of the solid material obtained in step (iv) is at least 1.2 mS / cm at 25°C, for example, at least 1.21 mS / cm or at least 1.25 mS / cm.

[0047] It has been found that the solid material obtained in step (iv) possesses both high ionic conductivity and surprisingly low electronic conductivity, making it a very attractive solid battery electrolyte material. According to a preferred embodiment of the present invention, the material obtained in step (iv) has a conductivity of 1 × 10⁻¹⁶ at 25°C. -4 Less than mS / cm, preferably 6 × 10 -5 A method is provided having an electronic conductivity of less than mS / cm. As shown in the attached examples, the inventors have found that, surprisingly, when X represents Br, I, or a combination thereof, the electronic conductivity at 25°C is very low, for example, 1 × 10⁻⁶ -9 Less than mS / cm or 1 × 10⁻⁶ -10 We found that the temperature can be less than mS / cm. Therefore, in some embodiments of the present invention, the material obtained in step (iv) can be 1 × 10 at 25°C. -5 Less than mS / cm, preferably 1 × 10⁻⁶ -6 A method is provided that has an electronic conductivity of less than mS / cm. In a particular embodiment of the present invention, X represents Br, I, or a combination thereof; The solid material obtained in step (iv) will be 1 × 10⁻¹⁶ at 25°C. -9 Less than mS / cm or 1 × 10⁻⁶ -10 It has an electronic conductivity of less than mS / cm.

[0048] In some particularly preferred embodiments of the present invention, a method is provided in which the material obtained in step (iv) has both high ionic conductivity and low electronic conductivity. This is possible when X represents Br, as shown in the appended examples. For example, in some embodiments of the method of the present invention, At least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, and most preferably X represents Br; The solid material obtained in step (iv) has an ionic conductivity of at least 1 mS / cm, preferably at least 1.1 mS / cm, and more preferably at least 1.2 mS / cm at 25°C; The solid material obtained in step (iv) will be 1 × 10⁻¹⁶ at 25°C. -9 Less than mS / cm or 1 × 10⁻⁶ -10 It has an electronic conductivity of less than mS / cm.

[0049] For example, in some embodiments, at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, and most preferably X represents Br; the solid material obtained in step (iv) has an ionic conductivity of at least 2 mS / cm at 25°C, and the solid material obtained in step (iv) has an ionic conductivity of 1 × 10⁻¹⁶ at 25°C. -9 Less than mS / cm or 1 × 10⁻⁶ -10 It has an electronic conductivity of less than mS / cm.

[0050] As shown in the attached examples, the method of the present invention provides high thermal stability ΔT for Li-S glass. x It has been found that this yields a glassy solid exhibiting the following properties. According to a preferred embodiment of the present invention, the material obtained in step (iv) has a thermal stability ΔT of over 100°C, preferably over 110°C, and more preferably over 115°C. x A method is provided which has thermal stability ΔT, in particular when X represents Br, I or a combination thereof. x The temperature is above 120°C, preferably above 125°C, and more preferably above 130°C.

[0051] In a particular very preferred embodiment, The solid material obtained in step (iv) has an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.3 mS / cm, at 25°C; The solid material obtained in step (iv) has a thermal stability ΔT of over 100°C, preferably over 110°C, and more preferably over 115°C. x Having; Preferably, the solid material obtained in step (iv) is 1 × 10 at 25°C. -5 Less than mS / cm, preferably 1 × 10⁻⁶ -6 A method is provided that has an electronic conductivity of less than mS / cm.

[0052] In a particular very preferred embodiment, X represents at least 50 mol% Br, preferably at least 80 mol% Br, and most preferably X represents Br; The solid material obtained in step (iv) has an ionic conductivity of at least 1 mS / cm, preferably at least 1.1 mS / cm, and more preferably at least 1.2 mS / cm at 25°C; The solid material obtained in step (iv) has a thermal stability ΔT of over 120°C, preferably over 125°C, and more preferably over 130°C. x Having; Preferably, the solid material obtained in step (iv) is 1 × 10 at 25°C. -9 Less than mS / cm or 1 × 10⁻⁶ -10 A method is provided that has an electronic conductivity of less than mS / cm.

[0053] For example, in some embodiments, X represents I or Br, preferably Br; the solid material obtained in step (iv) has an ionic conductivity of at least 1.5 mS / cm, more preferably at least 2 mS / cm, at 25°C, and the solid material obtained in step (iv) has a thermal stability ΔT above 115°C, preferably above 125°C. x It holds.

[0054] In some applications, the material obtained in step (iv) may preferably be provided in the form of a particulate solid, such as a powder. This may facilitate blending with cathode material, for example. The solid obtained in step (iv) may be obtained directly in the form of a particulate solid (such as a powder), or it may be ground into a particulate solid (such as a powder) (by milling, grinding, etc.). In other applications, the solid material obtained in step (iv) may preferably be provided in the form of a thin sheet or film, preferably with a thickness of less than 500 microns, and preferably less than 100 microns.

[0055] The preparation of the mixture in step (ii) may be carried out by any suitable means, preferably by mechanical milling (e.g., ball milling).

[0056] Step (iii) involves heating the mixture prepared in step (ii) to obtain a melt, i.e., heat-treating it at a temperature higher than the melting point of the mixture prepared in step (ii). Step (iii) preferably includes heat-treating the mixture prepared in step (ii) at a temperature of at least 400°C, preferably at least 600°C, and more preferably at least 800°C. The mixture is preferably held at this temperature for at least 15 minutes, preferably at least 30 minutes, and more preferably at least 2 hours.

[0057] The heat treatment may be carried out in a sealed container. The sealed container may be a sealed quartz tube or any other type of container that can withstand the heat treatment temperature and does not react with the glass components, and such a sealed container may be made from a material selected from magnesium oxide, boron nitride, copper, tungsten, silicon nitride, aluminum nitride, carbon, and combinations thereof. The heat treatment in step (iii) may be a single-stage heat treatment or a multi-stage heat treatment.

[0058] Step (iii) is preferably carried out under an inert gas atmosphere, preferably an inert atmosphere containing one or more noble gases (such as argon), and / or at a pressure of less than 1 atmosphere, preferably less than 0.1 atmospheres, and more preferably less than 0.01 atmospheres. Typically, and therefore preferably, step (iii) is carried out at 10 -4 Less than atmospheric pressure, preferably 10 -5 The process is carried out at a pressure below atmospheric pressure, preferably in an inert gas atmosphere, and more preferably in an inert atmosphere containing one or more noble gases (such as argon). The use of nitrogen as the inert atmosphere should be avoided in general due to the potential for reaction with the glass precursor.

[0059] In some embodiments of the method of the present invention, step (iv) is: (iv)a A step of rapidly cooling the molten material obtained in step (iii) to obtain a solid material; (iv)b A step of crushing the solid material from step (iv)a to obtain particulate solids such as powder; (iv)c Optional, By dissolving or suspending the particulate solid of step (iv)b in a liquid phase to obtain a solution or suspension, and then depositing from the solution or suspension to obtain a thin film or sheet; or The particulate solid from step (iv)b is reheated to a temperature sufficient to enable the stretching of the film or sheet, and the film or sheet is stretched. The process further includes the step of forming a thin film or sheet, preferably having a thickness of less than 500 microns, and preferably less than 100 microns.

[0060] In another embodiment, step (iv) includes quenching the molten material from step (iii) while maintaining a temperature high enough to allow for the stretching of a thin film or sheet, and stretching the film or sheet, preferably having a thickness of less than 500 microns, and more preferably less than 100 microns.

[0061] This method is preferably operated in a continuous process form to produce a continuous glass film or sheet that is cut to a desired size.

[0062] The quenching step in step (iv) is preferably carried out by directly contacting the molten material obtained in step (iii), or by contacting it with water, ice, optionally cooled gas (such as air), optionally cooled metal plate (by roller quenching, etc.), and / or a chemically inert mold, with the container closed or open (preferably closed).

[0063] The solid material obtained in step (iv) is preferably substantially free of gas impurities, and in particular, substantially free of gas impurities at the edges of the material.

[0064] The inventors intend to add small amounts of other materials during synthesis so that the general formula (I) of the resulting solid material is no longer respected, but this modification does not substantially affect the fundamental and novel properties of the solid material of the present invention. Such modifications are considered to be within the scope of general formula (I) for the purposes of the present invention.

[0065] Embodiment 2 In another aspect of the present invention, a solid material is provided which can be obtained by the method described herein (i.e., the method of Embodiment 1). Such a solid material is characterized in that it is substantially free of gas inclusions, and in particular substantially free of gas inclusions at the edges of the material. As shown in the appended examples, the method of the present invention makes it possible to obtain a material without edge bubbles.

[0066] Embodiment 3 In another aspect of the present invention, a solid composition is provided comprising a first solid material which is a solid material described herein (i.e., the solid material of Embodiment 2), and further comprising at least a second solid material having a different composition from the first solid material. The first solid material may exist in the form of discrete particles embedded in a matrix of the second solid material. Alternatively, the first and second solid materials may exist in the form of discrete particles blended together with a binder material and one or more further materials, the blend preferably being compressed. Alternatively, the first and second solid materials may exist in the form of different layers of a multilayer thin sheet or film, preferably with a total thickness of less than 500 microns, preferably less than 200 microns. Such a solid composition comprising a first solid material which is a solid material described herein, and further comprising at least a second solid material having a different composition from the first solid material, is particularly useful as a cathode, anode, or separator of an electrochemical cell, and particularly as a separator or cathode. In some embodiments, the second solid material is a cathode material such as a nickel-cobalt or nickel-manganese-cobalt cathode material.

[0067] Embodiment 4 In another aspect of the present invention, an electrochemical cell is provided comprising a solid material as described herein (i.e., the solid material of Embodiment 2). In particular, an electrochemical cell is provided in which the cathode, anode and / or separator comprises a solid material as defined herein. In some embodiments, an electrochemical cell is provided in which the cathode, anode and / or separator comprises a solid material as defined herein in the form of a solid composition comprising a first solid material which is a solid material as described herein, and further comprising at least a second solid material having a different composition from the first solid material. Such solid compositions are described in connection with another aspect of the present invention. In a particularly preferred embodiment of the present invention, an electrochemical cell is provided in which the separator comprises a solid material as defined herein, optionally in the form of a solid composition as described herein. In some embodiments, the separator consists of a solid material as described herein.

[0068] Embodiment 5 Another aspect of the present invention provides the use of a solid material described herein (i.e., the solid material of Embodiment 2) or a solid composition described herein (i.e., the solid composition of Embodiment 3) as a solid electrolyte for an electrochemical cell. Preferably, the use of a solid material described herein as a solid electrolyte for an electrochemical cell is provided.

[0069] In the context of the various embodiments of the present invention described herein, suitable electrochemically active cathode materials and suitable electrochemically active anode materials are known in the art. For example, the anode may include graphite carbon, metallic lithium, or a metal alloy containing lithium as the anode active material. For example, the cathode may include nickel-cobalt or nickel-manganese-cobalt cathode materials. The electrochemical cells described herein preferably have charge transport by Li + This is a lithium-ion-containing cell that operates using ions. The electrochemical cell may have a disc-shaped or prismatic shape. The electrochemical cell may include a housing that may be made of steel or aluminum. Multiple electrochemical cells can be combined to form an all-solid-state battery having both solid electrodes and a solid electrolyte.

[0070] Embodiment 6 Another aspect of the present invention relates to a battery, more specifically a lithium-ion battery or a lithium-metal battery, comprising at least one electrochemical cell containing the solid material described herein (i.e., the solid material of Embodiment 2), for example, two or more electrochemical cells described in Embodiment 4. Certain embodiments relate to a solid battery, preferably a lithium solid battery, comprising at least one electrochemical cell containing the solid material described herein (i.e., the solid material of Embodiment 2), for example, two or more electrochemical cells described in Embodiment 4. The electrochemical cells described in Embodiment 4 can be combined with each other, for example, in series or parallel connection. Series connection is preferred. Each of the electrochemical cells or batteries described herein can be used to manufacture or operate stationary applications such as automobiles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOSes, communication devices, or remote car locks, and energy storage devices for power plants.

[0071] Embodiment 7 A further aspect of the present invention is a method for manufacturing or operating stationary applications such as automobiles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOSes, communication equipment, remote car locks, and energy storage devices for power plants, by using at least one battery or at least one electrochemical cell (i.e., the electrochemical cell described in Embodiment 4) comprising the solid materials described herein.

[0072] Embodiment 8 Further aspects of the present disclosure relate to the use of electrochemical cells containing the solid material of the present invention (i.e., the electrochemical cell described in Embodiment 4) in motor vehicles, electric motor-driven bicycles, robots, aircraft (e.g., unmanned aerial vehicles including drones), ships, or fixed energy storage devices. The present invention further provides a device comprising at least one electrochemical cell as described in Embodiment 5. Mobility devices such as vehicles, e.g., automobiles, bicycles, aircraft, or water vehicles, e.g., boats or ships are preferred. Other examples of mobility devices are portable devices such as computers, particularly laptops, telephones, or power tools from the construction sector, e.g., particularly drills, battery-powered screwdrivers, or battery-powered tackers.

[0073] The present invention is further illustrated by the following, non-limiting embodiments. [Examples]

[0074] 1. Preparation of materials In the comparative example, 15 g of the final material was prepared using the following starting products: amorphous B2S3 (99 wt%), Li2S (99.9 wt%), B2O3 (99.95 wt%), and LiX (LiI (99.9 wt%), LiBr (99 wt%), LiCl (99.9 wt%)). Appropriate amounts of the starting materials were weighed and mixed in an argon-filled glove box and introduced into a carbon-coated silica ampoule. The tube was sealed and introduced into a vertical oscillating furnace. The molten material was homogenized at an internal temperature of 950°C for 30 minutes, and then rapidly cooled in water at room temperature. The ampoule was then opened in an argon-filled glove box. An orange or brown glassy material with good transparency was obtained.

[0075] In the examples, alternative synthesis was successfully carried out in which the amounts of boron and sulfur provided by B2S3 were supplied in the form of amorphous elemental B (99%) and elemental S (99.999%). Glass obtained starting from elemental boron and elemental sulfur instead of B2S3 was substantially free of edge bubbles and visible inclusions, while glass obtained starting from B2S3 was observed to have a large amount of visible edge bubbles and carbon inclusions from the ampoule. The presence of inclusions is problematic for post-processing of the glass. This type of defect can act as a nucleating agent, which is advantageous for the crystallization of the material. The presence of defects leads to a material that is no longer isotropic, thus posing a problem for protective behavior against dendritic crystals.

[0076] 2.Thermal stability ΔT x decision Thermal analysis was performed using a differential scanning calorimetry (DSC) 3500 Sirius. 5-10 mg of glassy material samples were placed in a sealed aluminum pan and analyzed using the following temperature profile: 100°C to 350°C at a rate of 10°C / min. For all samples, the glass transition temperature (T) was determined. g ) and the start of crystallization (T x ) was determined. Then, thermal stability was estimated from the simple difference between these values ​​(ΔT x =T x -T g ).

[0077] By constructing tangents to the baseline of the DSC curve before and after the glass transition, and determining the extrapolation start temperature from the intersection of these tangents, the glass transition temperature (T g ) is determined, which essentially corresponds to the temperature at which the highest gradient in the descent of the DSC baseline occurs before the exothermic crystallization peak. The T thus determined g The starting temperature is T g It was used as such.

[0078] 3. Determination of conductivity Ionic conductivity was measured by electrochemical impedance spectroscopy (EIS) at room temperature (25°C) for hot-pressed samples in pellet cells equipped with ion-blocking electrodes. The samples were densified at 350 MPa and 125°C for 5 minutes, and ionic conductivity was measured under an operating pressure of 125 MPa. For EIS, an excitation voltage of 10 mV was applied in the frequency range of 7 MHz to 1 Hz. The data were interpreted by equivalent circuit analysis.

[0079] Electronic conductivity was measured at room temperature (25°C) for samples hot-pressed in a pellet cell equipped with an ion-blocking electrode. Samples were densified at 350 MPa and 125°C for 5 minutes, and electronic conductivity was measured under an operating pressure of 125 MPa. Electronic conductivity was measured by stepwise potentiometer polarization at 0.2 V, 0.4 V, and 0.6 V for 20 minutes.

[0080] Both measurements were performed using a potentiostat equipped with a frequency analyzer (Biologic).

[0081] 4. Determination of the identity of the obtained glass Inductively coupled plasma atomic emission spectroscopy (ICP-OES) was applied to the glassy material of the example prepared as described above.

[0082] To avoid reaction with water or O2, the glassy material sample is weighed in a glow box under an Ar atmosphere and added to a microwave container. The acid combination is added, the container is closed, and the mixture is extinguished in the microwave until clear. The matrix elements (Li & B) are analyzed using the high-precision ICP-OES method.

[0083] S is determined via elemental analysis after sample preparation in an Ar-filled glove box. Sample preparation involves placing approximately 100 mg of the sample into a sealable capsule, followed by adding the sealed capsule and additives to a ceramic crucible. The filled crucible is then heated in an induction furnace under an O2 atmosphere. The present S is released from the sample, converted to SO2 gas, and detected by an SO2-specific IR detector. The detected SO2 signal is finally converted to the S concentration by using a calibration curve and taking into account the exact sample mass.

[0084] The composition of the glass was found to correspond to the overall formula predicted based on the molar ratio of the precursors subjected to melting and quenching, within the limits of expected experimental error and variation.

[0085] 5.Results [Table 1] [Table 2]

Claims

1. A method for preparing a solid material, (i) The following precursors: Li ２ S; Both boron and sulfur; B ２ O ３ ;and LiX (wherein X is F, Cl, Br, I, N) ３ , SCN, CN, OCN, BF ４ BH ４ The process of providing (or a combination thereof); (ii) A step of preparing a mixture containing the precursor provided in step (i); (iii) A step of heat-treating the mixture prepared in step (iii) to obtain a molten product; (iv) A step of rapidly cooling the molten material obtained in step (iii) to obtain the solid material, The molar ratio of the precursor in the mixture before rapid cooling is such that a composition conforming to general formula (I) is obtained in step (ii). ((Li 2 S) x (B 2 S 3 ) y (B 2 O 3 ) z ) A (LiX) B (I) (In the formula, x is in the range of 55 to 85; y is in the range of 15 to 45; z is in the range of 1 to 15; x + y + z = 100; The ratio A:B is within the range of 60:40 to 94:6), method.

2. The method according to claim 1, wherein X represents Cl, Br, I, or a combination thereof.

3. x is in the range of 62 to 68; y is within the range of 27 to 33; z is in the range of 1 to 8; The method according to claim 1, wherein x + y + z = 100.

4. x is approximately 65; y is approximately 30; The method according to claim 3, wherein z is approximately 5.

5. The method according to claim 1, wherein the solid material is a glassy solid.

6. The method according to claim 1, wherein the solid material has an ionic conductivity of at least 0.1 mS / cm at 25°C.

7. The solid material has a thermal stability ΔT exceeding 100°C ｘ and ΔT ｘ = T ｘ - T ｇ (where T ｘ is the crystallization start temperature determined by DSC, and T ｇ is the glass transition temperature determined by DSC), the method according to claim 1.

8. The method according to claim 1, wherein step (iii) includes heat-treating the mixture prepared in step (ii) to a temperature of at least 400°C.

9. The method according to claim 1, wherein step (ii) includes mechanical milling.

10. The method according to claim 1, wherein step (iii) is performed in a sealed container.

11. Process (iv) is, (iv) a step of rapidly cooling the molten material obtained in step (iii) to obtain a solid material; (iv)b A step of crushing the solid material from step (iv)a to obtain a particulate solid such as a powder; (iv)c Optional, By dissolving or suspending the particulate solid of step (iv)b in a liquid phase to obtain a solution or suspension, and then depositing from the solution or suspension to obtain a thin film or sheet; or The particulate solid from step (iv)b is reheated to a temperature sufficient to enable the stretching of the film or sheet, and the film or sheet is stretched. The method according to claim 1, further comprising the step of forming a thin film or sheet.

12. A solid material that is substantially free of gas impurities, Having a composition that conforms to general formula (I) ((Li 2 S) x (B 2 S 3 ) y (B 2 O 3 ) z ) A (LiX) B (I) (In the formula, x is in the range of 55 to 85; y is in the range of 15 to 45; z is in the range of 1 to 15; x + y + z = 100; The ratio A:B is within the range of 60:40 to 94:6), for solid materials.

13. An electrochemical cell comprising the solid material described in claim 12.

14. The electrochemical cell according to claim 13, comprising a cathode, an anode, and a separator, wherein the separator comprises the solid material described in claim 12.

15. Use of the solid material according to claim 12 as a solid electrolyte for an electrochemical cell.

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