Sulfide-based lithium-ion mixed halide conductive solid electrolyte and method for producing the same

Abstract

The present invention relates to a solid material that can be obtained by melt-quenching a mixture of lithium sulfide, boron sulfide, boron oxide, and lithium halide, thereby forming a glassy solid suitable for use as a lithium-ion conductive electrolyte. These sulfide-based lithium-ion conductive solid electrolytes exhibit high ionic conductivity.

Description

[Technical Field]

[0001] The present invention relates to a solid material that can be obtained by melt-quenching a mixture of lithium sulfide, boron sulfide, and boron oxide to form a glassy solid suitable for use as a lithium-ion conductive electrolyte. The present invention further relates to a method for preparing the solid material, an electrochemical cell such as a solid-state battery containing the solid material, and the use of the solid material, particularly as an electrolyte, in an electrochemical cell such as a solid-state battery. [Background technology]

[0002] The three main functional components of a lithium-ion battery are the negative electrode, the positive electrode, and the electrolyte. Although many variations exist, the negative electrode of a conventional lithium-ion cell is typically made from carbon, the positive electrode is typically made from a transition metal oxide (particularly oxides of cobalt, nickel, and / or manganese), and the electrolyte is typically a non-aqueous solvent containing a lithium salt. For example, a mixture of an organic carbonate 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, which poses a significant safety risk during normal operation and 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 spillage or leakage, 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. A new class of lithium-ion conductive solid electrolytes is sulfide-based amorphous solids (interchangeably referred to as glassy solids), such as Li2S-SiS2, Li2S-P2S5, or Li2S-B2S3. 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 can also prevent the formation of dendritic crystals, as glassy amorphous electrolyte materials can be obtained as high-density, defect-free films by melt quenching techniques.

[0005] Early studies on Li2S-B2S3 compositions with molar ratios of 70:30 and 60:40 reported ionic conductivity values ​​of 0.095 and 0.016 mS / cm, respectively (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 describes a Li2S-B2S3 type sulfide-based lithium-ion conductive solid electrolyte obtained from a mixture further containing P, Si, Ge, As, or Sb oxides in combination with lithium halide. The resulting glassy solid is said to have favorable lithium-ion conductivity, as well as electrochemical stability in direct contact with lithium metal and chemical stability to air and moisture.

[0008] International Publication No. 2016 / 089899 describes numerous glass systems (many of which are speculative or unsupported). Paragraphs 188 and 189 of International Publication No. 2016 / 089899 describe several Li2O-B2S3-SiS2-based systems.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0010]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] Most of the sulfide-based lithium-ion conductive solid electrolytes known in the art have the drawback that they have only low ionic conductivity. Therefore, there is a great need to provide a sulfide-based lithium-ion conductive solid electrolyte that combines both properties at present.

[0012] An object of the present invention is to provide a sulfide-based lithium-ion conductive solid electrolyte having high ionic conductivity. Another object of the present invention is to provide a sulfide-based lithium-ion conductive solid electrolyte having low electrical conductivity.

Means for Solving the Problems

[0013] The inventors have found that one or more objects of the present invention can be achieved by providing a sulfide-based lithium ion conductive solid electrolyte that can be obtained by melt quenching a combination of Li2S, B2S3, B2O3, LiI, and LiX (where X represents Cl, Br, or a combination thereof) in a clearly defined ratio. As shown in the attached examples, it has actually been observed that the resulting glassy solid exhibits high ionic conductivity and / or low electrical conductivity.

[0014] Thus, in a first aspect of the present invention, a solid material having a composition according to general formula (I) is provided: Li 2c+d+e B 2a+2b S 3a+c O 3b I d X e (I) (where X represents Br or Cl, or a combination thereof, a is in the range of 0.015 to 0.15, b is in the range of 0 to 0.04, c is in the range of 0.07 to 0.25, d is in the range of 0.001 to 0.24, e is in the range of 0.001 to 0.24).

[0015] In another aspect of the present invention, a solid material can be obtained by melt quenching a mixture of A, B, and C, wherein the molar ratio of A, B, and C in the mixture before quenching is in the range of 40:30:30 to 98:1:1. A solid material is provided. Here, component A has the general formula (II): xLi2S - yB2S3 - zB2O3 (II) (where x is in the range of 55 to 85, y is in the range of 15 to 45, z is in the range of 0 to 15, x + y + z = 100), Component B is LiI, Component C is LiX (wherein X represents Br, Cl, or a combination thereof).

[0016] In another aspect of the present invention, a method for preparing a solid material, comprising the following steps: (i) The following precursors: • Li2S, • B2S3, and / or both boron and sulfur, • B2O3 (optional selection) LiI, and • A step of providing LiX (wherein X represents Cl, Br, or a combination thereof), (ii) A step of preparing a mixture comprising the precursor provided in step (i), Here, In the above mixture, the molar ratios of the elements Li, S, B, O, I, and X are, It matches the general formula (I) as defined herein, or In the above mixture, the molar ratio of the precursor is A step that matches the general formula (II) defined herein, (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product, A method is provided which includes (iv) quenching the molten material obtained in step (iii) to obtain a solid material.

[0017] 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, and further comprises at least a second solid material having a different composition from the first solid material.

[0018] In another aspect of the present invention, an electrochemical cell comprising a solid material described herein is provided.

[0019] Another aspect of the present invention provides the use of a solid material or a solid composition described herein as a solid electrolyte for an electrochemical cell.

[0020] 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 a solid material as described herein, for example, two or more electrochemical cells as described herein.

[0021] A further aspect of the present invention is a method for creating or operating fixed 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 employing at least one battery or at least one electrochemical cell (i.e., an electrochemical cell as described herein) comprising the solid materials described herein.

[0022] Further aspects of this disclosure include the use of electrochemical cells comprising the solid material of the present invention (i.e., electrochemical cells as described herein) in automobiles, electric motor-driven bicycles, robots, aircraft (e.g., unmanned aerial vehicles including drones), ships, or fixed energy storage facilities.

[0023] Another aspect of the present invention provides the use of a combination of LiI and a lithium salt of formula LiX (wherein X represents Cl, Br, or a combination thereof) for improving the ionic conductivity of glassy solids, particularly for improving the ionic conductivity of sulfide-based lithium-ion conductive solid electrolytes. [Modes for carrying out the invention]

[0024] Detailed description of the invention In the following detailed description, in order to enable the implementation of the present invention, preferred embodiments will be described in detail. Although the present invention is described with reference to these specific preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention includes a number of alternatives, modifications, and equivalents that will become apparent in view of the following detailed description.

[0025] As referred to herein, the ionic conductivity refers to the ionic conductivity determined by electrochemical impedance spectroscopy (EIS) at 25°C. This is preferably determined on an ion-blocking electrode on a hot-pressed sample densified at 350 MPa for 5 minutes at 125°C, and then 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 is interpreted by equivalent circuit analysis. A suitable conductivity analyzer is a potentiostat having a frequency analyzer, such as those available from Biologic.

[0026] As referred to herein, the electronic conductivity refers to the electronic conductivity determined at 25°C. This is preferably determined on an ion-blocking electrode on a hot-pressed sample densified at 350 MPa for 5 minutes at 125°C, and then the electronic conductivity is measured at 25°C under an operating pressure of 125 MPa. Preferably, the electronic conductivity is measured through a stepwise potential difference electrode at 0.2, 0.4, and 0.6 V for 20 minutes. A suitable conductivity analyzer is a potentiostat having a frequency analyzer, such as those available from Biologic.

[0027] As referred to herein, the molar ratio, for example, the molar ratio of components A, B, and C, means that the ratio of A, B, and C is defined in the following unit mol / mol / mol.

[0028] In a first aspect of the present invention, a solid material having a composition according to general formula (I) is provided: Li 2c+d+e B 2a+2b S 3a+c O3b I d X e (I) (In the formula, X represents Br or Cl, or a combination thereof. a is within the range of 0.015 to 0.15. b is in the range of 0 to 0.04. c is in the range of 0.07 to 0.25. d is in the range of 0.001 to 0.24. e is within the range of 0.001 to 0.24).

[0029] While we do not wish to be bound by any theory, the inventors believe that the solid material according to formula (I) is the result obtained when a mixture of Li2S, B2S3, B2O3, LiI, and LiX (wherein X represents Cl, Br, or a combination thereof, in the context of other aspects of the invention and as described herein in the examples) is melt-quenched in clearly defined ratios.

[0030] General formula (I) (wherein, a is within the range of 0.02 to 0.09. b is in the range of 0 to 0.03. c is in the range of 0.09 to 0.20. d is in the range of 0.001 to 0.21. e is in the range of 0.001 to 0.21. more, a is within the range of 0.03 to 0.085. b is in the range of 0.007 to 0.02. c is in the range of 0.10 to 0.20. d is in the range of 0.001 to 0.15. A solid material having a composition in which e is in the range of 0.001 to 0.15 is preferably provided.

[0031] Generally, d and e are preferably in the range of 0.005 to 0.15, more preferably in the range of 0.009 to 0.10, and more preferably in the range of 0.01 to 0.07. In some embodiments, d and e are in the range of 0.001 to 0.15, more preferably in the range of 0.005 to 0.15, and more preferably in the range of 0.01 to 0.15. In some embodiments, d and e are in the range of 0.005 to 0.10, more preferably in the range of 0.009 to 0.08, and more preferably in the range of 0.01 to 0.07.

[0032] Therefore, in some embodiments of the present invention, the general formula (I) (wherein, a is within the range of 0.03 to 0.085. b is in the range of 0 to 0.03. c is in the range of 0.10 to 0.20. d is in the range of 0.001 to 0.15, preferably in the range of 0.005 to 0.10, more preferably in the range of 0.01 to 0.07. e is in the range of 0.001 to 0.15, preferably in the range of 0.005 to 0.10, more preferably in the range of 0.01 to 0.07. more, a is within the range of 0.04 to 0.085. b is in the range of 0.007 to 0.025. c is in the range of 0.10 to 0.18. d is in the range of 0.001 to 0.15, preferably in the range of 0.005 to 0.10, more preferably in the range of 0.01 to 0.07. A solid material is provided having a composition in which e is in the range of 0.001 to 0.15, preferably in the range of 0.005 to 0.10, and more preferably in the range of 0.01 to 0.07.

[0033] Therefore, in some embodiments of the present invention, the general formula (I) (wherein, a is in the range of 0.050 to 0.080. b is in the range of 0.009 to 0.020. c is in the range of 0.11 to 0.18. d is in the range of 0.005 to 0.15. A solid material is provided having a composition in which e is in the range of 0.005 to 0.15.

[0034] According to a very preferred embodiment of the present invention, general formula (I) (wherein, a is in the range of 0.053 to 0.066, preferably in the range of 0.056 to 0.063, more preferably in the range of 0.058 to 0.061, and most preferably a is about 0.060. b is in the range of 0.009 to 0.011, preferably in the range of 0.0095 to 0.010, and more preferably b is about 0.010. c is in the range of 0.11 to 0.14, preferably in the range of 0.0125 to 0.135, and more preferably c is about 0.0130. d is in the range of 0.045 to 0.09, preferably in the range of 0.055 to 0.075, more preferably in the range of 0.060 to 0.070, and most preferably d is about 0.066. A solid material is provided having a composition in which e is in the range of 0.045 to 0.09, preferably in the range of 0.055 to 0.075, more preferably in the range of 0.060 to 0.070, and most preferably e is about 0.066.

[0035] According to a very preferred embodiment of the present invention, general formula (I) (wherein, a is in the range of 0.055 to 0.075, preferably in the range of 0.06 to 0.07, and more preferably a is about 0.066. b is in the range of 0.0085 to 0.015, preferably in the range of 0.009 to 0.01, and more preferably b is about 0.011. c is in the range of 0.0135 to 0.0155, preferably in the range of 0.014 to 0.015, and more preferably c is about 0.0143. d is in the range of 0.035 to 0.055, preferably in the range of 0.04 to 0.05, and more preferably d is about 0.047. A solid material is provided having a composition in which e is in the range of 0.035 to 0.055, preferably in the range of 0.04 to 0.05, and more preferably e is about 0.047.

[0036] According to a very preferred embodiment of the present invention, general formula (I) (wherein, a is in the range of 0.065 to 0.080, preferably in the range of 0.069 to 0.075, more preferably in the range of 0.070 to 0.072, and most preferably a is about 0.071. b is in the range of 0.010 to 0.015, preferably in the range of 0.011 to 0.013, and more preferably b is about 0.012. c is in the range of 0.13 to 0.17, preferably in the range of 0.15 to 0.16, and more preferably c is 0.155. d is in the range of 0.025 to 0.045, preferably in the range of 0.027 to 0.040, more preferably in the range of 0.029 to 0.035, and most preferably d is about 0.030. A solid material is provided having a composition in which e is in the range of 0.025 to 0.045, preferably in the range of 0.027 to 0.040, more preferably in the range of 0.029 to 0.035, and most preferably e is about 0.030.

[0037] According to a very preferred embodiment of the present invention, general formula (I) (wherein, a is in the range of 0.070 to 0.080, preferably in the range of 0.072 to 0.079, more preferably in the range of 0.074 to 0.077, and most preferably a is about 0.076. b is in the range of 0.010 to 0.015, preferably in the range of 0.012 to 0.014, and more preferably b is about 0.013. c is in the range of 0.15 to 0.18, preferably in the range of 0.16 to 0.17, and more preferably c is about 0.166. d is in the range of 0.005 to 0.025, preferably in the range of 0.008 to 0.020, more preferably in the range of 0.010 to 0.017, and most preferably d is about 0.014. A solid material is provided having a composition in which e is in the range of 0.005 to 0.025, preferably in the range of 0.008 to 0.020, more preferably in the range of 0.010 to 0.017, and most preferably e is about 0.014.

[0038] In each embodiment of the composition according to general formula (I) described herein, the molar ratio was calculated such that the sum of 5a + 5b + 3c + 2d + 2e is in the range of 0.9 to 1.1, preferably in the range of 0.99 to 1.01, and most preferably about 1.

[0039] As will be understood by those skilled in the art, a solid material having a composition according to general formula (I), when prepared, for example by melt quenching, may have a small amount of impurity phase, which typically consists mainly of a precursor used to prepare the solid material or an intermediate formed from said precursor.

[0040] In a second aspect of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, The molar ratios of A, B, and C in the mixture before quenching are within the range of 40:30:30 to 98:1:1. Component A is general formula (II): xLi2S-yB2S3-zB2O3(II) (In the formula, x is in the range of 55 to 85, preferably in the range of 55 to 75, more preferably in the range of 60 to 70. y is in the range of 15 to 45, preferably in the range of 20 to 40, more preferably in the range of 25 to 35. z is in the range of 0 to 15, preferably in the range of 0 to 10, more preferably in the range of 0 to 6. According to x+y+z=100, Component B is LiI, A solid material is provided in which component C is LiX (wherein X represents Br, Cl, or a combination thereof).

[0041] In a preferred embodiment of the present invention, the solid material can be obtained by melt-quenching a mixture of A, B, and C, x is in the range of 62 to 68, preferably in the range of 63 to 67, 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, 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, more preferably in the range of 4 to 6. A solid material is provided where x + y + z = 100.

[0042] According to a very preferred embodiment of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is approximately 65, y is approximately 30, A solid material is provided in which z is approximately 5.

[0043] Generally, the molar ratio of A, B, and C in the mixture before quenching is preferably in the range of 50:25:25 to 98:1:1, more preferably in the range of 56:22:22 to 90:5:5, and more preferably in the range of 64:18:18 to 80:10:10. In some embodiments, the molar ratio of A, B, and C in the mixture before quenching is preferably in the range of 60:20:20 to 95:3:2, more preferably in the range of 76:12:12 to 90:5:5, and more preferably in the range of 70:15:15 to 82:9:9. In some very preferred embodiments, the molar ratio of A, B, and C in the mixture before quenching is preferably in the range of 50:25:25 to 96:2:2, more preferably in the range of 60:20:20 to 90:5:5, and more preferably in the range of 70:15:15 to 80:10:10.

[0044] In preferred embodiments, the molar ratio of A, B, and C in the mixture before quenching is in the range of 50:25:25 to 70:15:15, preferably in the range of 56:22:22 to 64:18:18, more preferably in the range of 58:21:21 to 62:19:19, and most preferably about 60:20:20. In some embodiments, the molar ratio of A, B, and C in the mixture before quenching is in the range of 64:18:18 to 76:12:12, preferably in the range of 66:17:17 to 74:13:13, more preferably in the range of 68:16:16 to 72:14:14, and most preferably about 70:15:15. In some embodiments, the molar ratio of A, B, and C in the mixture before quenching is in the range of 75:15:15 to 88:6:6, preferably in the range of 76:12:12 to 84:8:8, more preferably in the range of 78:11:11 to 82:9:9, and most preferably about 80:10:10. In some embodiments, the molar ratio of A, B, and C in the mixture before quenching is in the range of 84:8:8 to 98:1:1, preferably in the range of 86:7:7 to 94:3:3, more preferably in the range of 88:6:6 to 92:4:4, and most preferably about 90:5:5.

[0045] Therefore, in some embodiments of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is in the range of 62 to 68, preferably in the range of 63 to 67, 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, 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, more preferably in the range of 4 to 6. x+y+z=100, A solid material is provided in which the molar ratio of A, B, and C in the mixture before quenching is in the range of 50:25:25 to 96:2:2, preferably in the range of 60:20:20 to 90:5:5, and more preferably in the range of 70:15:15 to 80:10:10.

[0046] In some embodiments of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is approximately 65, y is approximately 30, z is approximately 5, x+y+z=100, A solid material is provided in which the molar ratio of A, B, and C in the mixture before quenching is in the range of 50:25:25 to 70:15:15, preferably in the range of 56:22:22 to 64:18:18, more preferably in the range of 58:21:21 to 62:19:19, and most preferably about 60:20:20.

[0047] In some embodiments of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is approximately 65, y is approximately 30, z is approximately 5, x+y+z=100, A solid material is provided in which the molar ratio of A, B, and C in the mixture before quenching is in the range of 64:18:18 to 76:12:12, preferably in the range of 66:17:17 to 74:13:13, more preferably in the range of 68:16:16 to 72:14:14, and most preferably about 70:15:15.

[0048] In some embodiments of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is approximately 65, y is approximately 30, z is approximately 5, x+y+z=100, A solid material is provided in which the molar ratio of A, B, and C in the mixture before quenching is in the range of 75:15:15 to 88:6:6, preferably in the range of 76:12:12 to 84:8:8, more preferably in the range of 78:11:11 to 82:9:9, and most preferably about 80:10:10.

[0049] In some embodiments of the present invention, a solid material can be obtained by melt-quenching a mixture of A, B, and C, x is approximately 65, y is approximately 30, z is approximately 5, x+y+z=100, A solid material is provided in which the molar ratio of A, B, and C in the mixture before quenching is in the range of 84:8:8 to 98:1:1, preferably in the range of 86:7:7 to 94:3:3, more preferably in the range of 88:6:6 to 92:4:4, and most preferably about 90:5:5.

[0050] In some preferred embodiments of the present invention, the solid material that can be obtained by melt-quenching a mixture of A, B, and C as described herein is a solid material having a composition according to general formula (I) as described herein (i.e., the solid material of the first embodiment of the present invention).

[0051] Solid materials according to different embodiments of the present invention as described herein, namely solid materials having a composition according to general formula (I) as described herein (i.e., solid materials of the first embodiment of the present invention), and solid materials that can be obtained by melt-quenching a mixture of A, B, and C as described herein (i.e., solid materials of the second embodiment of the present invention), are collectively referred to as “solid materials” (i.e., solid materials of the first or second embodiment of the present invention).

[0052] According to a preferred embodiment of the present invention, a solid material is provided in which X represents Br, Cl, or a combination thereof.

[0053] The solid material of the present invention is typically a glassy solid, which can be obtained by melting and quenching a mixture of precursors, as described elsewhere in this specification. In some embodiments, the solid material is in the form of a monolithic glass, such as molten-cast monolithic glass. The glassy solid is preferably essentially free of a crystalline phase. This may mean, in some embodiments, that the amount of the crystalline phase, as measured 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 the intensity of its reflection is more than 10% higher than the background.

[0054] According to a preferred embodiment of the present invention, a solid material is provided in which X represents Br, Cl, or a combination thereof, and in which at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br.

[0055] The solid material of the present invention has been found to have a remarkably high ionic conductivity. According to a preferred embodiment of the present invention, a solid material is provided having an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.2 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 when X represents Br, the ionic conductivity at 25°C can be as high as 0.93 mS / cm. Therefore, in some embodiments of the present invention, a solid material is provided having an ionic conductivity of at least 0.3 mS / cm, preferably at least 0.40 mS / cm, and more preferably at least 0.54 mS / cm, at 25°C. In a particular embodiment of the present invention, the solid material of the present invention has the following: - At least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, most preferably X represents Br, and - The ionic conductivity at 25°C is at least 0.40 mS / cm, preferably at least 0.50 mS / cm, and more preferably at least 0.54 mS / cm. For example, in some embodiments of the solid material of the present invention, at least 80 mol% of X represents Br and the ionic conductivity of the solid material at 25°C is at least 0.3 mS / cm, or X represents Br and the ionic conductivity of the solid material at 25°C is at least 0.54 mS / cm, for example, at least 0.60 mS / cm or at least 0.75 mS / cm.

[0056] A preferred embodiment of the present invention provides a solid material in which X represents Br, Cl, or a combination thereof, and at least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl.

[0057] As shown in the attached examples, the inventors have surprisingly found that when at least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl, and most preferably when X represents Cl, the ionic conductivity at 25°C can be as high as 0.71 mS / cm. Therefore, in some embodiments of the present invention, a solid material is provided having an ionic conductivity of at least 0.40 mS / cm, preferably at least 0.50 mS / cm, and more preferably at least 0.62 mS / cm at 25°C. In a particular embodiment of the present invention, the solid material of the present invention has the following: - At least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl, most preferably X represents Cl, and - The ionic conductivity at 25°C is at least 0.40 mS / cm, preferably at least 0.50 mS / cm, and more preferably at least 0.62 mS / cm. For example, in some embodiments of the solid material of the present invention, at least 80 mol% of X represents Cl and the ionic conductivity of the solid material at 25°C is at least 0.3 mS / cm, or X represents Cl and the ionic conductivity of the solid material at 25°C is at least 0.62 mS / cm, for example, at least 0.65 mS / cm, or at least 0.70 mS / cm.

[0058] The solid material of the present invention has been found to be a very attractive solid battery electrolyte material, combining the high ionic conductivity with surprisingly low electronic conductivity. According to a preferred embodiment of the present invention, at 25°C, 1 × 10⁻⁶ -4 Less than mS / cm, preferably 1 × 10 -5 A solid material having an electronic conductivity of less than mS / cm is provided. As shown in the attached examples, the inventors have surprisingly found that when X represents Br, Cl, or a combination thereof, the electronic conductivity at 25°C is 1 × 10⁻⁶. -5 Less than mS / cm, or 8 × 10⁻⁶ -6 We found that the level can be very low, such as less than mS / cm. In a specific embodiment of the present invention: - X represents Br, Cl, or a combination thereof, and - The solid material is 1.0 × 10 at 25°C. -6 Less than mS / cm, or 1.0 × 10⁻⁶ -5 It has an electronic conductivity of less than mS / cm.

[0059] In some particularly preferred embodiments of the present invention, a material is provided that combines high ionic conductivity with low electronic conductivity. This is possible when X represents Br, as shown in the appended examples. For example, in some embodiments of the solid material of the present invention: - At least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, most preferably X represents Br. - The solid material has an ionic conductivity of at least 0.30 mS / cm, preferably at least 0.40 mS / cm, and more preferably at least 0.54 mS / cm at 25°C, and - The solid material is 5.0 × 10 at 25℃. -4 Less than mS / cm or 1 × 10⁻⁶ -5 It has an electronic conductivity of less than mS / cm. For example, in some embodiments, at least 50 mol% of X represents Br, preferably at least 80 mol% of X represents Br, most preferably X represents Br, the solid material has an ionic conductivity of at least 0.54 mS / cm at 25°C, and the solid material has an ionic conductivity of 5 × 10 at 25°C. -4 It has an electronic conductivity of less than mS / cm.

[0060] In some particularly preferred embodiments of the present invention, a material is provided that combines high ionic conductivity with low electronic conductivity. This is possible when X represents Cl, as shown in the appended examples. For example, in some embodiments of the solid material of the present invention: - At least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl, most preferably X represents Cl. - The solid material has an ionic conductivity of at least 0.40 mS / cm, preferably at least 0.50 mS / cm, and more preferably at least 0.62 mS / cm at 25°C, and - The solid material is 5 × 10 at 25℃. -5 Less than mS / cm, or 1 × 10⁻⁶ -5 It has an electronic conductivity of less than mS / cm. For example, in some embodiments, at least 50 mol% of X represents Cl, preferably at least 80 mol% of X represents Cl, most preferably X represents Cl, the solid material has an ionic conductivity of at least 0.62 mS / cm at 25°C, and the solid material has an ionic conductivity of 1 × 10 at 25°C. -5 It has an electronic conductivity of less than mS / cm.

[0061] As described throughout this application, the solid materials of the present invention can be obtained by melt-quenching a mixture of precursors to obtain a glassy solid. In some applications, the material may be preferably provided in the form of a particulate solid, such as a powder. This may facilitate blending with, for example, a cathode material. The solid may be obtained directly in the form of a particulate solid (such as a powder) or may be ground into a particulate solid (such as a powder) (by milling, grinding, etc.). In other applications, the solid material may be preferably provided in the form of a thin sheet or film, preferably a sheet or film having a thickness of less than 500 microns, preferably less than 100 microns.

[0062] The inventors intend to add small amounts of other materials during synthesis in such a way that the general formula (I) of the resulting solid material is no longer respected, or in such a way that the general formula (II) is no longer respected, but the changes do not substantially affect the basic and novel properties (plural) of the solid material of the present invention. Such modifications are considered to be within the scope of general formula (I) or (II) for the purposes of the present invention.

[0063] A third aspect of the present invention relates to a method for preparing a solid material, comprising the following steps: (i) The following precursors: • Li2S, • B2S3, and / or both boron and sulfur, • B2O3 (optional selection) • LiI, and • A step of providing LiX (wherein X represents Cl, Br, or a combination thereof), (ii) A step of preparing a mixture comprising the precursor provided in step (i), Here, In the above mixture, the molar ratios of the elements Li, S, B, O, I, and X are, General formula (I): Li 2c+d+e B 2a+2b S 3a+c O 3b I d X e (I) (In the formula, X represents Br or Cl, or a combination thereof. a is within the range of 0.015 to 0.15. b is in the range of 0 to 0.04. c is in the range of 0.07 to 0.25. d is in the range of 0.001 to 0.24. e is within the range of 0.001 to 0.24. or In the above mixture, the molar ratio of the precursor is General formula (II): xLi2S-yB2S3-zB2O3(II) (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 0 to 15. The steps that match x+y+z=100, (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product, A method is provided which includes (iv) quenching the molten material obtained in step (iii) to obtain a solid material.

[0064] This method is generally referred to as the melt quenching method of the present invention. This process is cost-effective and easily scalable. In the context of the first aspect of the present invention, preferred embodiments of general formula (I) described herein, particularly a, b, c, d, and e, are equally applicable to methods for preparing solid materials. Similarly, in the context of the second aspect of the present invention, preferred embodiments of general formula (II) described herein, particularly x, y, and z, are equally applicable to the melt quenching method of the present invention. Furthermore, preferred embodiments of solid materials of the present invention (i.e., according to the first or second aspect of the present invention) are generally equally applicable to the melt quenching method of the third aspect of the present invention (for example, relating to the identity and conductivity of X).

[0065] 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 are not particularly limited in this invention.

[0066] The preparation of the mixture in step (ii) may be carried out by any suitable means, preferably by mechanical grinding (e.g., ball grinding).

[0067] Step (iii) includes 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). Preferably, step (iii) 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 kept at this temperature for at least 1 hour, preferably at least 2 hours, and more preferably at least 4 hours.

[0068] The heat treatment may be carried out in a closed container. The closed 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, such as a closed container 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 or multi-stage heat treatment.

[0069] 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, more preferably less than 0.01 atmospheres. Typically, therefore, step (iii) is carried out at 10 -4 Less than atmospheric pressure, preferably 10 -5 The process is preferably carried out at a pressure below atmospheric pressure, preferably under an inert gas atmosphere, and more preferably under an inert atmosphere containing one or more noble gases (such as argon). The use of nitrogen as the inert atmosphere should generally be avoided due to the potential for reaction with the glass precursor.

[0070] The melt quenching method of the present invention is very preferably for the preparation of a solid material according to a first or second embodiment of the present invention.

[0071] In some embodiments of the melt quenching method of the present invention, step (iv) is the following steps: (iv)a A step of quenching the molten material obtained in step (iii) to obtain a solid material, (iv)b A step of crushing the solid material from step (iv) to obtain a particulate solid such as a powder, (iv)c Optionally, a step of forming a thin film or sheet, preferably a film or sheet having a thickness of less than 500 microns, preferably less than 100 microns, - A forming step, which involves dissolving or suspending the particulate solid from step (iv)b in a liquid phase to obtain a solution or suspension, and then depositing it from the solution or suspension to obtain a thin film or sheet, or - The process further includes the step of forming by reheating the particulate solid from step (iv)b to a temperature sufficient to enable the stretching of a film or sheet, and then stretching the film or sheet.

[0072] In an alternative embodiment, step (iv) includes quenching the molten material from step (iii) while maintaining a temperature sufficiently high to allow 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.

[0073] The method is preferably operated in the form of a continuous process to produce a continuous glass film or sheet that is cut to the desired size.

[0074] The quenching step in step (iv) is preferably carried out by directly contacting the molten material obtained in step (iii), or by bringing the container into contact with water, ice, optionally cooled gas (e.g., air), optionally cooled metal plate (e.g., via a roller quench), and / or a chemically inert mold, while the container is closed or open (preferably while closed).

[0075] A fourth aspect of the present invention provides a solid composition comprising a first solid material (i.e., a solid material according to the first or second aspect of the present invention), 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. The first solid material may exist in the form of individual particles embedded in a matrix of the second solid material. Alternatively, the first and second solid materials may exist in the form of individual 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 having a total thickness of less than 500 microns, preferably less than 200 microns. Such a solid composition comprising a first solid material (i.e., a solid material according to the first aspect of the present invention), and further comprising at least a second solid material having a different composition from the first solid material, is particularly useful as a positive electrode, negative electrode, or separator in an electrochemical cell, and particularly as a separator or positive electrode. In some embodiments, the second solid material is a cathode material such as a nickel-cobalt or nickel-manganese-cobalt cathode material.

[0076] A fifth aspect of the present invention provides an electrochemical cell comprising a solid material as described herein (i.e., the solid materials of the first and second aspects of the present invention). In particular, an electrochemical cell is provided in which the positive electrode, negative electrode, and / or separator comprises a solid material as defined herein. In some embodiments, an electrochemical cell is provided in which the positive electrode, negative electrode, 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 a solid composition is described in the context of another aspect of the present invention. In a particularly preferred embodiment of the present invention, an electrochemical cell is provided in which the separator optionally comprises a solid material as defined herein in the form of a solid composition as described herein. In some embodiments, the separator consists of a solid material as described herein.

[0077] A sixth aspect of the present invention provides the use of a solid material described herein (i.e., a solid material according to the first or second aspect of the present invention) or a solid composition described herein (i.e., a solid composition according to the fourth aspect of the present invention) 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.

[0078] 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 lithium-containing metal alloy as the anode active material. For example, the cathode may include nickel-cobalt or nickel-manganese-cobalt cathode materials. The electrochemical cell described herein is preferably a lithium-ion-containing cell, and charge transport is Li +This is achieved by ions. The electrochemical cell may have a disc-like or prismatic shape. The electrochemical cell may include a housing which may be derived from steel or aluminum. Multiple electrochemical cells may be combined into any solid-state battery having both solid electrodes and solid electrolytes.

[0079] A seventh 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 according to the first or second aspect of the present invention), for example, two or more electrochemical cells as described in the fifth aspect of the present invention. Specific 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 according to the first or second aspect of the present invention), for example, two or more electrochemical cells as described in the fifth aspect of the present invention. The electrochemical cells as described in the fifth aspect of the present invention can be combined with each other, for example, in series or parallel connections. Series connection is preferred. Each battery of the electrochemical cells as described herein can be used to create or operate fixed applications such as automobiles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOS, communication equipment or remote car locks, and energy storage devices for power plants.

[0080] A further aspect of the present invention is a method for creating or operating fixed 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 employing at least one battery or at least one electrochemical cell (i.e., an electrochemical cell as described in a fifth aspect of the present invention) comprising the solid materials described herein.

[0081] An eighth aspect of the present disclosure is the use of an electrochemical cell comprising the solid material of the present invention (i.e., an electrochemical cell as described in the fifth aspect of the present invention) in an automobile, 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 facility. The present invention further provides a device comprising at least one electrochemical cell as described in the fifth aspect of the present invention. Preferably, it is a mobile device, such as a transport vehicle, e.g., an automobile, a bicycle, an aircraft, or a water vehicle such as a boat or ship. Other examples of mobile devices are portable ones, e.g., computers, in particular laptops, telephones, or power tools, e.g., from the construction sector, in particular drills, battery-powered screwdrivers, or battery-powered tackers.

[0082] The present invention is further illustrated by the following, less limited, embodiments. [Examples]

[0083] 1. Preparation of materials For each 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%), LiI (99.95 wt%), and LiBr (99.9 wt%) or LiCl (99.9 wt%). In an argon-filled glove box, the appropriate amount of starting material was weighed, mixed, and introduced into a boron nitride crucible placed in a silica ampoule. The tube was sealed and introduced into a vertical oscillating furnace. The molten material was homogenized at an internal temperature of 850°C for 5 hours, and then quenched in water at room temperature. The ampoule was then opened in an argon-filled glove box. A glassy material with good transparency and an orange or brown color was obtained.

[0084] In some examples, alternative synthesis was carried out to successfully provide the amounts of boron and sulfur derived from B2S3 in the form of amorphous element B (99 wt%) and element S (99.999 wt%).

[0085] The present invention is further illustrated by the following, less limited, embodiments.

[0086] 1.1. Preparation of Comparative Example 3 (CEX3) For each example, 15 g of the final material was prepared using the following starting products: amorphous B2S3 (99 wt%), Li2S (99.9 wt%), and B2O3 (99.95 wt%), and X (detailed in the table below). In an argon-filled glove box, the appropriate amount of starting material was weighed, mixed, 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 quenched in water at room temperature. The ampoule was then opened in an argon-filled glove box. A glassy material having good transparency and being yellow, orange, or brown was obtained.

[0087] 2. Determination of conductivity Ionic conductivity was measured by electrochemical impedance spectroscopy (EIS) at room temperature (25°C) on a hot-pressed sample in a pellet cell with an ion-blocking electrode. The sample was densified at 350 MPa for 5 minutes at 125°C. 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.

[0088] Electronic conductivity was measured at room temperature (25°C) on hot-pressed samples in pellet cells with ion-blocking electrodes. The samples were densified at 350 MPa for 5 minutes at 125°C. Electronic conductivity was measured under an operating pressure of 125 MPa. Electronic conductivity was measured at 0.2, 0.4, and 0.6 V over 20 minutes via stepwise potential difference electrodes.

[0089] Both measurements were performed using a potentiostat equipped with a frequency analyzer (Biologic).

[0090] 3. Determination of the identity of the obtained glass Inductively coupled plasma emission spectroscopy (ICP-OES) was applied to the glassy material of the example prepared as described above.

[0091] A sample of glassy material is weighed in a glove box under an Ar atmosphere to avoid reaction with water or O2, and then added to a microwave chamber. A combination of acids is added, the chamber is closed, and the sample is microwaved until clear. Matrix elements (Li and B) are analyzed using the high-precision ICP-OES method.

[0092] S is determined via elemental analysis after sample preparation in an Ar-filled glove box. Sample preparation involves placing approximately 100 mg of 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 then converted to the S concentration using a calibration curve and taking into account the exact mass of the sample.

[0093] The glass composition was found to correspond within the acceptable range of predicted experimental error and within the range of variation in the overall formula predicted based on the molar ratio of the precursor subjected to melt quenching.

[0094] 4. Results [Table 1] [Table 2]

Claims

1. A solid material that can be obtained by melt-quenching a mixture of A, B, and C, wherein the molar ratio of A, B, and C in the mixture before quenching is in the range of 40:30:30 to 98:1:

1. Component A is general formula (II): xLi ２ S-yB ２ S ３ -zB ２ O ３ (II) (In the formula, x is in the range of 55 to 85, preferably in the range of 55 to 75, more preferably in the range of 60 to 70. y is in the range of 15 to 45, preferably in the range of 20 to 40, and more preferably in the range of 25 to 35. z is in the range of 0 to 15, preferably in the range of 0 to 10, more preferably in the range of 0 to 6. According to x + y + z = 100, Component B is LiI, A solid material in which component C is LiX (wherein X represents Br, Cl, or a combination thereof).

2. The aforementioned solid material is defined by general formula (I): Li ２ｃ＋ｄ＋ｅ B ２ａ＋２ｂ S ３ａ＋ｃ O ３ｂ I ｄ X ｅ (I) (In the formula, X represents Br or Cl, or a combination thereof) a is in the range of 0.015 to 0.

15. b is in the range of 0 to 0.

04. c is in the range of 0.07 to 0.

25. d is in the range of 0.001 to 0.

24. The solid material according to claim 1, having a composition in which e is in the range of 0.001 to 0.

24.

3. x is in the range of 62 to 68, preferably in the range of 63 to 67, 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, 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, more preferably in the range of 4 to 6. x + y + z = 100. The solid material according to claim 1 or claim 2.

4. The solid material according to any one of claims 1 to 3, wherein the molar ratio of A, B, and C in the mixture before quenching is in the range of 50:25:25 to 96:2:2, preferably in the range of 60:20:20 to 90:5:5, and more preferably in the range of 70:15:15 to 80:10:

10.

5. A solid material according to any one of claims 1 to 4, wherein X represents Br or Cl.

6. The solid material according to any one of claims 1 to 5, wherein the material is a glassy solid.

7. The solid material according to any one of claims 1 to 6, wherein the material has an ionic conductivity of at least 0.3 mS / cm, preferably at least 0.4 mS / cm, at 25°C.

8. A method for preparing a solid material, preferably a solid material as defined in any one of claims 1 to 7, comprising the following steps: (i) The following precursors: ・ Li ２ S、 ・ B ２ S ３ , and / or both boron and sulfur, ・Optionally select B ２ O ３ , LiI, and - A step of providing LiX (wherein X represents Cl, Br, or a combination thereof), (ii) A step of preparing a mixture comprising the precursor provided in step (i), Here, - The step of the mixture wherein the molar ratio of the precursor matches the general formula (II) defined in claims 1 to 4, and the molar ratio of A, B, and C in the mixture is as defined in claims 1 to 4. (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a molten product, A method comprising the step of (iv) quenching the molten material obtained in step (iii) to obtain the solid material, preferably a solid material as defined in any one of claims 1 to 7.

9. An electrochemical cell comprising a solid material as defined in any one of claims 1 to 7.

10. The electrochemical cell according to claim 9, wherein the separator comprises a solid material as defined in any one of claims 1 to 7.

11. Use of a solid material as defined in any one of claims 1 to 7 as a solid electrolyte for an electrochemical cell.

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