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

Abstract

The present invention relates to a solid material obtained by melt-quenching a mixture of lithium sulfide, boron sulfide and boron oxide, thereby forming a glassy solid suitable for use as a lithium ion conductive electrolyte. These sulfide-based lithium ion conductive solid electrolytes exhibit a large thermal stability as supported by a large ΔT x , particularly a ΔT exceeding 100 °C x and are thus highly thermally stable.

Description

Technical Field

[0001] The present invention relates to a solid material obtained by melting and quenching a mixture of lithium sulfide, boron sulfide, and boron oxide, thereby forming 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 an all-solid-state battery containing the solid material, and the use of the solid material, particularly as an electrolyte, in an electrochemical cell such as an all-solid-state battery.

Background Art

[0002] The three main functional components of a lithium ion battery are the anode, the cathode, and the electrolyte. Although there are many variations, the anode of a conventional lithium ion battery is typically made of carbon, the cathode is typically made of a transition metal oxide (especially 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 the composition, especially the solvent, is flammable, posing a significant safety risk during normal operation, particularly in the event of an accident. Another drawback is inherent to the liquid nature of the electrolyte and is related to the risk of leakage and the increased risk of environmental contamination in the case of spillage or leakage.

[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 the risks of EHS (environment, health, and safety). A new class of lithium ion conductive solid electrolytes is Li 2 S-SiS 2 、Li 2 S-P 2 S 5 、or Li 2 S-B 2 S 3It is a sulfide-based amorphous solid (which may be equivalently referred to as a glassy solid). In the glassy solid electrolyte material, since there is no crystal path, isotropic conduction with substantially no grain boundary resistance can be obtained. Since there are no grain boundaries in the glassy electrolyte material, the formation of dendritic crystals can also be prevented. This is because the glassy amorphous electrolyte material can be obtained as a high-density and defect-free film by a melt-quenching method.

[0005] A major issue in the production of glassy solid electrolytes is to avoid crystal regions in the solid material. The thermal stability ΔT of the glass x can be characterized as the stability against crystallization, and is the temperature difference between the crystallization start temperature (T x ) and the glass transition temperature (T g ), that is, ΔT x = T x - T g . It is determined by ΔT x . When ΔT x is large, generally, it is accompanied by an improvement in the glass-forming ability and an increase in the glass stability during post-treatment.

[0006] In the initial studies on Li 2 S-B 2 S 3 compositions with molar ratios of 70:30 and 60:40, ΔT x values of about 70 °C and about 110 °C were reported respectively (Zhang et al, Solid State Ionics 1990, 38, 217-224).

[0007] U.S. Patent No. 5,500,291 contemplates a sulfide-based lithium ion conductive solid electrolyte of the Li 2 S-SiS 2 -Li 4 SiO 4 type.

[0008] International Publication No. 2020 / 254314 (A1) discloses Li 2 S-B 2 S obtained from a mixture further containing an oxide of P, Si, Ge, As or Sb in combination with lithium halide.3 A sulfide-based lithium ion conductive solid electrolyte of the type is contemplated. The resulting glassy solid is said to have a favorable lithium ion conductivity, as well as electrochemical stability in direct contact with lithium metal, and chemical stability against air and moisture. The ΔT of these solids x is in the range of 5 to 36 °C (Table 3 of WO 2020 / 254314 (A1)).

[0009] WO 2016 / 089899 (A1) contemplates a number of glass systems (many of which are speculative or unsubstantiated). Paragraphs 186 and 188 of WO 2016 / 089899 (A1) suggest adding oxygen to improve ΔT x . In paragraph 190 of WO 2016 / 089899 (A1), Li 2 S / Li 2 0-B 2 S 3 -SiS 2 -based systems are speculated to have a ΔT x exceeding 100 °C.

[0010] A drawback of most sulfide-based lithium ion conductive solid electrolytes known in the art is that they have either a low ionic conductivity or a high ΔT x . Therefore, there is a great need to provide a sulfide-based lithium ion conductive solid electrolyte that combines both properties at present.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0012] [Non-Patent Document 1] Zhang et al,Solid State Ionics 1990,38,217-224 [Summary of the Invention] [Problems to be Solved by the Invention]

[0013] An object of the present invention is to provide a sulfide-based lithium ion conductive solid electrolyte having a large ΔT x , particularly a ΔT exceeding 100°C x x . Another object of the present invention is to provide a sulfide-based lithium ion conductive solid electrolyte having a high ionic conductivity. Another object of the present invention is to provide a sulfide-based lithium ion conductive solid electrolyte having a low electric conductivity. [Means for Solving the Problems]

[0014] The inventors of the present invention have found that one or more objects of the present invention can be achieved by providing a sulfide-based lithium ion conductive solid electrolyte obtained by melting and quenching a combination of Li 2 2 S;B 2 2 S 3 3 and B 2 2 O 3 3 in a clearly defined ratio. As shown in the attached examples, the obtained glassy solid actually exhibits high thermal stability ΔT x x , high ionic conductivity and / or low electric conductivity in Li-S-based glasses.

[0015] Embodiment 1 Therefore, in a first aspect of the present invention, the general formula (I) Li 2a 2a B 2b+2c 2b+2c S a+3b a+3b O 3c 3c (I) (wherein a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, and a solid material having a composition according to (where c is in the range of 0.003 to 0.024) is provided.

[0016] Embodiment 2 In another aspect of the present invention, a solid material can be obtained by melt - quenching a mixture of the following precursors: ·Li 2 S, and ·B 2 S 3 and / or both boron and sulfur, and ·B 2 O 3 where the molar ratio of the precursors in the mixture before quenching is a molar ratio such that a composition according to the general formula (II) is obtained. xLi 2 S - yB 2 S 3 - zB 2 O 3 (II) (where x is in the range of 62 to 68, y is in the range of 27 to 33, z is in the range of 1 to 9, and x + y + z = 100).

[0017] Embodiment 3 In another aspect of the present invention, a method for preparing a solid material, comprising: (i) providing the following precursors: ·Li 2 S, ·B 2 S 3 and / or both boron and sulfur, and ·B 2 O 3 ; and (ii) preparing a mixture comprising the precursors provided in step (i), · wherein the molar ratio of the elements Li, S, B, and O in the mixture is according to the general formula (I) Li 2a B2b+2c S a+3b O 3c (I) (wherein, a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, c is in the range of 0.003 to 0.024) coincides with, or · In the mixture, the molar ratio of the precursors is represented by the general formula (II) xLi 2 S-yB 2 S 3 -zB 2 O 3 (II) (wherein, x is in the range of 62 to 68, y is in the range of 27 to 33, z is in the range of 1 to 9, x + y + z = 100) coincides with, a step of, (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a melt, (iv) A step of rapidly cooling the melt obtained in step (iii) to obtain a solid material, and a method including the steps is provided.

[0018] Embodiment 4 In another aspect of the present invention, a solid composition is provided that includes a first solid material that is the solid material described herein (i.e., the solid material of Embodiment 1 or 2), and further includes at least a second solid material having a composition different from that of the first solid material.

[0019] Embodiment 5 In another aspect of the present invention, an electrochemical cell is provided that includes the solid material described herein (i.e., the solid material of Embodiment 1 or 2).

[0020] Embodiment 6 In another aspect of the present invention, there is provided the use of the solid material described herein (i.e., the solid material of Embodiment 1 or 2) or the solid composition described herein (i.e., the solid composition of Embodiment 4) as a solid electrolyte for an electrochemical cell.

[0021] Embodiment 7 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 comprising the solid material described herein (i.e., the solid material of Embodiment 1 or 2), for example, two or more electrochemical cells as described in Embodiment 5.

[0022] Embodiment 8 A further aspect of the present invention is a method of fabricating or operating a stationary application such as a vehicle, a computer, a personal digital assistant, a mobile phone, a watch, a camcorder, a digital camera, a thermometer, a calculator, a laptop BIOS, a communication device, a remote car lock, and an energy storage device for a power plant, by using at least one battery or at least one electrochemical cell comprising the solid material described herein (i.e., the electrochemical cell described in Example 5).

[0023] Embodiment 9 A further aspect of the present disclosure is the use of an electrochemical cell comprising the solid material of the present invention (i.e., the electrochemical cell described in Embodiment 5) in an automobile, a bicycle operated by an electric motor, a robot, an aircraft (e.g., an unmanned aircraft including a drone), a ship, or a stationary energy storage device.

Mode for Carrying Out the Invention

[0024] In the following detailed description, preferred embodiments are described in detail in order to implement the present invention. 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. 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.

[0025] As referred to in this specification, the glass transition temperature (T g ) refers to the onset temperature of the glass transition determined by differential scanning calorimetry (DSC). This is preferably determined by constructing tangents to the DSC curve baselines before and after the glass transition and determining the extrapolated onset temperature by the intersection of these tangents, and essentially corresponds to the temperature at which the highest gradient in the drop of the DSC baseline occurs before the exothermic crystallization peak. The DSC is preferably recorded using a temperature profile of 100 °C to 350 °C at a rate of 10 °C / min, and is preferably recorded for a sample of 5 to 10 mg in a sealed aluminum pan. A suitable DSC apparatus is the DSC3500 Sirius.

[0026] The thermal stability (ΔT x ) referred to in this specification is the difference between the crystallization onset temperature (T x ) determined by DSC and the glass transition temperature (T g ) determined by DSC. In other words, ΔT x = T x - T g . As explained in the previous paragraph, when referred to in this specification, the glass transition temperature (T g ) refers to the onset temperature of the glass transition determined by differential scanning calorimetry (DSC).

[0027] The ionic conductivity referred to in this specification refers to the ionic conductivity measured at 25 °C by electrochemical impedance spectroscopy (EIS). The ionic conductivity is preferably measured using an ion blocking electrode on a hot pressed sample densified at 350 MPa, 125 °C for 5 minutes, 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 equipped with a frequency analyzer such as those available from Biologic.

[0028] The electrical conductivity referred to in this specification refers to the electrical conductivity measured at 25°C. The electrical conductivity is preferably determined using an ion blocking electrode on a hot pressed sample densified at 350 MPa for 5 minutes at 125°C, and then the electrical conductivity is measured at 25°C under an operating pressure of 125 MPa. Preferably, the electrical conductivity is measured by stepwise potentiostatic polarization at 0.2, 0.4, and 0.6 V for 20 minutes. A suitable conductivity analyzer is a potentiostat equipped with a frequency analyzer such as those available from Biologic.

[0029] Embodiment 1 In a first aspect of the present invention, general formula (I) Li 2a B 2b+2c S a+3b O 3c (I) (wherein, a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, c is in the range of 0.003 to 0.024) provides a solid material having a composition. Although not wishing to be bound by any theory, the inventors believe that the solid material according to formula (I) is a mixture of Li 2 S, B 2 S 3 and B 2 O 3 obtained when melted and quenched in a defined ratio as described herein in the context and examples of other aspects of the present invention.

[0030] General formula (I) (wherein, a is in the range of 0.168 to 0.183, b is in the range of 0.075 to 0.086, c is in the range of 0.003 to 0.024, more preferably, in the formula, a is in the range of 0.172 to 0.179, b is in the range of 0.079 to 0.084, c is in the range of 0.008 to 0.019) Preferably, a solid material having a composition according to the following is provided.

[0031] Generally, it is preferable that c is in the range of 0.008 to 0.019, preferably in the range of 0.011 to 0.016, and more preferably in the range of 0.012 to 0.015.

[0032] Therefore, in some embodiments of the present invention, the general formula (I) (wherein a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, c is in the range of 0.008 to 0.019, preferably in the range of 0.011 to 0.016, and more preferably in the range of 0.012 to 0.015, More preferably, in the formula, a is in the range of 0.172 to 0.179, b is in the range of 0.079 to 0.084, c is in the range of 0.008 to 0.019, preferably in the range of 0.011 to 0.016, and more preferably in the range of 0.012 to 0.015) A solid material having a composition according to the following is provided.

[0033] According to a highly preferred embodiment of the present invention, the general formula (I) (wherein a is in the range of 0.173 to 0.178, preferably in the range of 0.175 to 0.177, b is in the range of 0.079 to 0.083, preferably in the range of 0.080 to 0.082, c is in the range of 0.011 to 0.016, preferably in the range of 0.013 to 0.015) provides a solid material having a composition according to the following.

[0034] Therefore, in some embodiments of the present invention, the general formula (I) (wherein a is in the range of 0.175 to 0.177, b is in the range of 0.080 to 0.082, c is in the range of 0.011 to 0.016, preferably in the range of 0.013 to 0.015), a solid material having a composition according to the following is provided.

[0035] In each of the embodiments of the composition according to the general formula (I) described herein, the molar ratio is calculated such that the sum of 3a + 5b + 5c 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.

[0036] When the solid material having the composition according to the general formula (I) is prepared, for example, by melt-quenching, it may typically be accompanied by a small amount of impurity phase consisting mainly of precursors or intermediates formed from the precursors used to prepare the solid material.

[0037] Embodiment 2 In another aspect of the present invention, the following precursors: ·Li 2 S, ·B 2 S 3 and / or both boron and sulfur, and ·B 2 O 3 A solid material can be provided by melt-quenching a mixture of, where the molar ratio of the precursors in the mixture before quenching is according to the general formula (II) xLi 2 S - yB 2 S 3 -zB 2 O 3 (II) (wherein, x is in the range of 62 to 68, y is in the range of 27 to 33, z is in the range of 1 to 9, x + y + z = 100) is a molar ratio such that a composition according to the following is obtained.

[0038] In a preferred embodiment of the present invention, a solid material (i.e., the solid material of Embodiment 2) that can be obtained by melting and quenching is provided, where x is in the range of 63 to 67, preferably in the range of 64 to 66, y is in the range of 28 to 32, preferably in the range of 29 to 31, z is preferably in the range of 2 to 8, preferably in the range of 4 to 6.

[0039] In some embodiments, x is in the range of 64 to 66, y is in the range of 29 to 31, z is in the range of 1 to 9, preferably in the range of 2 to 8, more preferably in the range of 4 to 6.

[0040] In a further preferred embodiment of the present invention, a solid material (i.e., the solid material of Embodiment 2) that can be obtained by melting and quenching is provided, where, x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, 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 9, preferably in the range of 2 to 8, more preferably in the range of 4 to 6.

[0041] In some embodiments, x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, y is in the range of 28 to 32, preferably in the range of 29 to 31, z is in the range of 1 to 9, preferably in the range of 2 to 8, more preferably in the range of 4 to 6.

[0042] In some embodiments, x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, y is in the range of 29 to 31, z is in the range of 1 to 9, preferably in the range of 2 to 8, more preferably in the range of 4 to 6.

[0043] In some embodiments, x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, 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 2 to 8, preferably in the range of 4 to 6.

[0044] In some embodiments, x is in the range of 64.5 to 65.5, preferably in the range of 64.8 to 65.2, y is in the range of 28 to 32, preferably in the range of 29 to 31, z is in the range of 4 to 6.

[0045] In a further preferred embodiment of the present invention, a solid material (i.e., the solid material of Embodiment 2) obtainable by melt - quenching is provided, where x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, y is in the range of 29.2 to 30.8, preferably in the range of 29.5 to 30.5, more preferably in the range of 29.8 to 30.2, z is in the range of 4.2 to 5.8, preferably in the range of 4.5 to 5.5, more preferably in the range of 4.8 to 5.2.

[0046] In some embodiments, x is in the range of 64.5 to 65.5, y is in the range of 29.5 to 30.5, z is in the range of 4.2 to 5.8, preferably in the range of 4.5 to 5.5, more preferably in the range of 4.8 to 5.2.

[0047] In some embodiments, x is in the range of 64.8 to 65.2, y is in the range of 29.8 to 30.2, z is in the range of 4.2 to 5.8, preferably in the range of 4.5 to 5.5, more preferably in the range of 4.8 to 5.2.

[0048] According to a highly preferred embodiment of the present invention, a solid material (i.e., the solid material of Embodiment 2) obtainable by melt-quenching is provided, where x is about 65, y is about 30, z is about 5.

[0049] While not wishing to be bound by any theory, generally, and thus in some preferred embodiments of the present invention, the solid material obtainable by the melt-quenching described herein is believed to be the solid material having the composition according to the general formula (I) described herein (i.e., the solid material of Embodiment 1).

[0050] The solid materials according to various aspects of the present invention described herein, i.e., the solid material having the composition according to the general formula (I) described herein (i.e., the solid material of Embodiment 1) and the solid material obtainable by the melt-quenching described herein (i.e., the solid material of Embodiment 2), are collectively referred to as the "solid material" (i.e., the solid material of Embodiment 1 or 2).

[0051] The solid material of the present invention is typically a glassy solid and 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 a melt-cast monolithic glass. The glassy solid preferably contains essentially no crystalline phase. This may mean that in some embodiments, the amount of crystalline phase determined by X-ray diffraction is less than 5% by volume, preferably less than 2% by volume, more preferably less than 1% by volume of the solid material. A phase is considered crystalline if its reflection intensity exceeds the background by more than 10%.

[0052] The solid material of the present invention has been found to have surprisingly high ionic conductivity. According to a preferred embodiment of the present invention, a solid material having an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.15 mS / cm at 25 °C is provided.

[0053] The solid material of the present invention has both high ionic conductivity and surprisingly low electrical conductivity, which has been found to make it a very attractive solid-state battery electrolyte material. According to a preferred embodiment of the present invention, a solid material having an electrical conductivity of less than 1×10 -4 mS / cm, preferably less than 8×10 -5 mS / cm at 25 °C is provided.

[0054] As shown in the attached examples, the glassy solid of the present invention has been found to exhibit extremely high thermal stability ΔT x . According to a preferred embodiment of the present invention, a solid material having a thermal stability ΔT x exceeding 100 °C, preferably exceeding 110 °C, more preferably exceeding 112 °C is provided.

[0055] In certain very preferred embodiments, a solid material of the present invention is provided, where - the solid material has an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.15 mS / cm at 25 °C, - The solid material has a thermal stability ΔT exceeding 100 °C, preferably exceeding 110 °C, more preferably exceeding 112 °C x and - Preferably, the solid material has an electrical conductivity of less than 1 × 10 -4 mS / cm at 25 °C, preferably less than 8 × 10 -5 mS / cm

[0056] 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, it may be preferable for the material to be provided in the form of a particulate solid such as a powder. This can facilitate, for example, blending with a cathode material. The solid can be obtained directly in the form of a particulate solid (such as a powder) or can be milled (such as by milling, micronization, etc.) to form a particulate solid (such as a powder). In other applications, the solid material may preferably be 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

[0057] The inventors contemplate adding small amounts of other materials during synthesis such that the general formula (I) of the resulting solid material is no longer considered or the general formula (II) is no longer considered, where the changes do not substantially affect the basic and novel properties of the solid materials of the present invention. Such variations are considered to be within the scope of general formula (I) or (II) for the purposes of the present invention

[0058] Embodiment 3 In another aspect of the present invention, a method for preparing a solid material, comprising (i) providing the following precursors ·Li 2 S ·B 2 S 3 and / or both boron and sulfur, and ·B 2 O 3 providing step (ii) A step of preparing a mixture containing the precursor provided in step (i), wherein · The molar ratio of elements Li, S, B, and O in the mixture is represented by the general formula (I) Li 2a B 2b+2c S a+3b O 3c (I) (wherein a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, c is in the range of 0.003 to 0.024) or or · In the mixture, the molar ratio of the precursor is represented by the general formula (II) xLi 2 S-yB 2 S 3 -zB 2 O 3 (II) (wherein x is in the range of 62 to 68, y is in the range of 27 to 33, z is in the range of 1 to 9, x + y + z = 100), and (iii) A step of heat-treating the mixture prepared in step (ii) to obtain a melt, and (iv) A step of rapidly cooling the melt obtained in step (iii) to obtain a solid material. A method including these steps is provided.

[0059] This method is generally referred to as the melt - quenching method of the present invention. This process is cost - effective and easily scalable. The general formula (I) described herein in the context of Embodiment 1, particularly the preferred embodiments of a, b, and c, are equally applicable to the melt - quenching method of Embodiment 3. Similarly, the general formula (II) described herein in relation to Embodiment 2, particularly the preferred embodiments of x, y, and z, are equally applicable to the melt - quenching method of Embodiment 3. In addition, the preferred embodiments of the solid materials of the present invention (i.e., of Embodiment 1 or 2) are generally (e.g., with respect to conductivity, thermal stability, etc.) equally applicable to the melt - quenching method of Embodiment 3.

[0060] The fact that both boron and sulfur are provided in step (i) should be interpreted to mean that elemental boron and elemental sulfur are provided. Elemental boron and elemental sulfur may be provided in an amorphous form or a crystalline form, and the specific allotrope used does not particularly limit the present invention.

[0061] Preparing the mixture of step (ii) may be carried out by any suitable means, preferably by mechanical milling (e.g., ball milling treatment).

[0062] Step (iii) includes heating the mixture prepared in step (ii) to obtain a melt, i.e., heat - treating at a temperature higher than the melting temperature 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, more preferably at least 800 °C. The mixture is preferably held at this temperature for at least 15 minutes, preferably at least 30 minutes, more preferably at least 2 hours.

[0063] The heat treatment may be carried out in a sealed vessel. The sealed vessel may be a sealed quartz tube or any other type of vessel that can withstand the heat treatment temperature and is not affected by the reaction with the glass components. Such a sealed vessel is made of 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.

[0064] 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 atmosphere, more preferably less than 0.01 atmosphere. Typically, therefore preferably, step (iii) is carried out at a pressure of less than 10 -4 atmospheres, preferably less than 10 -5 atmospheres, preferably under an inert gas atmosphere, preferably an inert atmosphere containing one or more noble gases (such as argon). The use of nitrogen as an inert atmosphere should generally be avoided considering the potential reaction with the glass precursor.

[0065] The melt-quenching method of the present invention is very preferably for preparing the solid material according to Embodiment 1 or Embodiment 2 described herein.

[0066] In some embodiments of the melt-quenching method of the present invention, step (iv) is (iv)a step of quenching the melt obtained in step (iii) to obtain a solid material, and (iv)b step of pulverizing the solid material of step (iv)a to obtain a granular solid such as a powder, and (iv) Optionally, a thin film or sheet, preferably a film or sheet having a thickness of less than 500 microns, preferably less than 100 microns, is - a step of dissolving or suspending the granular 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 - Further comprising a step of reheating the granular solid in step (iv)b to a temperature sufficient to allow stretching of the film or sheet, and forming the film or sheet by stretching the film or sheet.

[0067] In an alternative embodiment, step (iv) comprises a step of quenching the melt of step (iii) while maintaining a temperature high enough to allow stretching of the thin film or sheet, and a step of stretching the film or sheet, preferably stretching a film or sheet having a thickness of less than 500 microns, preferably less than 100 microns.

[0068] 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.

[0069] The quenching step in step (iv) is preferably carried out by bringing the melt obtained in step (iii) into direct contact, or by contacting with water, ice, optionally cooled gas (such as air), optionally cooled metal plate (by roller quenching, etc.), and / or chemically inert mold while the vessel container is closed or open (preferably closed).

[0070] Embodiment 4 In another aspect of the invention, there is provided a solid composition comprising a first solid material which is a solid material described herein (i.e., the solid material of Embodiment 1 or 2), and further comprising at least a second solid material having a composition different from that of the first solid material. The first solid material may be present in the form of discrete particles embedded in a matrix of the second solid material. Alternatively, the first solid material and the second solid material may be present in the form of discrete particles optionally blended in combination with a binder material and one or more additional materials, and the blend is preferably compressed. Alternatively, the first solid material and the second solid material may be present in the form of different layers of a multilayer thin sheet or film, preferably a multilayer thin sheet or film having 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 composition different from that of the first solid material is particularly useful as a cathode, anode or separator of an electrochemical cell, 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.

[0071] Embodiment 5 In another aspect of the invention, there is provided an electrochemical cell comprising a solid material described herein (i.e., the solid material of Embodiment 1 or 2). In particular, there is provided an electrochemical cell in which the cathode, anode and / or separator comprises a solid material as defined herein. In some embodiments, there is provided an electrochemical cell in which the cathode, anode and / or separator comprises 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 composition different from that of the first solid material, in the form of a solid material as defined herein. Such solid compositions are described in connection with another aspect of the invention. In a particularly preferred embodiment of the invention, there is provided an electrochemical cell in which the separator comprises a solid material as defined herein, optionally in the form of a solid composition described herein. In some embodiments, the separator consists of a solid material described herein.

[0072] Embodiment 6 In another aspect of the present invention, there is provided the use of a solid material described herein (i.e., the solid material of Embodiment 1 or 2) or a solid composition described herein (i.e., the solid composition of Embodiment 4) as a solid electrolyte for an electrochemical cell. Preferably, there is provided the use of a solid material described herein as a solid electrolyte for an electrochemical cell.

[0073] In the context of the various aspects 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 an anode active material. For example, the cathode may include a nickel-cobalt or nickel-manganese-cobalt cathode material. The electrochemical cell described herein preferably is a lithium-ion-containing cell in which charge transport is effected by Li + ions. The electrochemical cell may have a disk-shaped or prismatic shape. The electrochemical cell can include a housing which can be made of steel or aluminum. A plurality of electrochemical cells can be combined to form an all-solid-state battery having both a solid electrode and a solid electrolyte.

[0074] Embodiment 7 Another aspect of the present invention relates to a battery, more specifically, at least one electrochemical cell comprising the solid materials described herein (i.e., the solid materials of Embodiment 1 or 2), for example, a lithium-ion battery comprising two or more electrochemical cells described in Embodiment 5. Certain embodiments relate to a solid-state battery, preferably, at least one electrochemical cell comprising the solid materials described herein (i.e., the solid materials of Embodiment 1 or 2), for example, a lithium solid-state battery comprising two or more electrochemical cells described in Embodiment 5. The electrochemical cells described in Embodiment 5 can be combined with each other, for example, in series connection or parallel connection. Series connection is preferred. Each of the electrochemical cells described herein can be used to fabricate or operate fixed applications such as vehicles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOS, communication devices, or remote car locks, and energy storage devices for power plants.

[0075] Embodiment 8 A further aspect of the present invention is a method for manufacturing or operating fixed applications such as vehicles, computers, personal digital assistants, mobile phones, watches, camcorders, digital cameras, thermometers, calculators, laptop BIOS, communication devices, remote car locks, and energy storage devices for power plants by using at least one battery or at least one electrochemical cell comprising the solid materials described herein (i.e., the electrochemical cell described in Example 5).

[0076] Embodiment 9 A further aspect of the present disclosure is the use of an electrochemical cell (i.e., the electrochemical cell described in Embodiment 5) comprising the solid material of the present invention in an automobile, a bicycle operated by an electric motor, a robot, an aircraft (e.g., an unmanned aircraft including a drone), a ship, or a stationary energy storage device. The present invention further provides a device comprising at least one electrochemical cell described in Embodiment 5. Mobile devices such as vehicles, e.g., automobiles, bicycles, aircraft, or watercraft, e.g., boats or ships, are preferred. Other examples of mobile devices are portable ones, e.g., computers, especially laptops, phones, or e.g., power tools from the construction sector, especially drills, battery-driven screwdrivers or battery-driven tackers.

[0077] The present invention is further illustrated by the following non-limiting examples.

Examples

[0078] 1. Preparation of Materials For each example, 15 g of the final material was produced using the following starting products: amorphous B 2 S 3 (99 wt%), Li 2 S (99.9 wt%) and B 2 O 3 (99.95 wt%). In an argon-filled glove box, appropriate amounts of the starting materials were weighed, mixed, and introduced into a carbon-coated silica ampoule. The tube was sealed and introduced into a vertical rocking furnace. The melt 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. An orange or brown glassy material with good transparency was obtained.

[0079] In some examples, an alternative synthesis was carried out and succeeded in which the amounts of boron and sulfur contributed by B 2 S 3 were provided in the form of amorphous elemental B (99 wt%) and elemental S (99.999 wt%).

[0080] 2. Thermal Stability ΔT xDetermination Thermal analysis was performed using a differential scanning calorimeter DSC 3500 Sirius. Samples of 5 - 10 mg of the glassy material were placed in sealed aluminum pans and analyzed using a temperature profile from 100 °C to 350 °C at a rate of 10 °C / min. For all samples, the glass transition temperature (T g ) and the onset of crystallization (T x ) were determined. Next, the thermal stability was estimated from the simple difference between these values (ΔT x = T x - T g ).

[0081] The glass transition temperature (T g ) was determined by constructing tangents to the DSC curve baseline before and after the glass transition and determining the extrapolation start temperature by the intersection of these tangents, which essentially corresponds to the temperature at which the highest gradient in the drop of the DSC baseline occurs before the exothermic crystallization peak. The T g start temperature thus obtained was designated as T g .

[0082] 3. Measurement of Conductivity Ionic conductivity was measured by electrochemical impedance spectroscopy (EIS) at room temperature (25 °C) in a hot - pressed sample in a pellet cell equipped with ion - blocking electrodes. The sample was densified at 350 MPa and 125 °C for 5 minutes. The 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 from 7 MHz to 1 Hz. The data were interpreted by equivalent circuit analysis.

[0083] Electrical conductivity was measured at room temperature (25 °C) in a hot - pressed sample in a pellet cell equipped with ion - blocking electrodes. The sample was densified at 350 MPa and 125 °C for 5 minutes. The electrical conductivity was measured under an operating pressure of 125 MPa. The electrical conductivity was measured by stepwise potentiostatic polarization at 0.2, 0.4, and 0.6 V for 20 minutes.

[0084] Both measurements were performed using a potentiostat equipped with a frequency analyzer (Biologic).

[0085] 4. Determination of the identity of the obtained glass Inductively coupled plasma optical emission spectrometry (ICP-OES) was applied to the glassy materials of the examples prepared as described above.

[0086] Samples of the glassy materials were weighed in a glove box under an Ar atmosphere to avoid reaction with water or O 2 and added to a microwave vessel. An acid combination was added, the vessel was closed, and digested in the microwave until it became transparent. The matrix elements (Li & B) were analyzed using a high-precision ICP-OES method.

[0087] S is determined via elemental analysis after sample preparation in an Ar-filled glove box. Sample preparation consists of inserting approximately 100 mg of the sample into a sealed capsule, and then adding the sealed capsule and additives to a ceramic crucible. Subsequently, the filled crucible is heated in an induction furnace under an O 2 atmosphere. The S present is released from the sample and converted to SO 2 gas, which is detected by a specific IR detector. The detected SO 2 signal is finally converted to the S concentration by using a calibration curve and taking into account the accurate sample mass. 2 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-quenching within the expected margins of experimental error and variation.

[0088]

[0089] 5. Results In the following table, the comparative examples are not included in the present invention, and the examples are according to the present invention.

[0090]

Table 1

[0091] ​

Table 2

Claims

1. General formula (I) Li ２ａ B ２ｂ＋２ｃ S ａ＋３ｂ O ３ｃ (I) (wherein a is in the range of 0.165 to 0.187, b is in the range of 0.073 to 0.089, c is in the range of 0.003 to 0.024), a solid material having a composition according to this formula.

2. a is in the range of 0.168 to 0.183, b is in the range of 0.075 to 0.086, c is in the range of 0.003 to 0.024, the solid material according to Claim 1.

3. a is in the range of 0.172 to 0.179, b is in the range of 0.079 to 0.084, c is in the range of 0.008 to 0.019, the solid material according to Claim 2.

4. 3a + 5b + 5c = 1, the solid material according to any one of Claims 1 to 3.

5. A solid material, preferably the solid material according to any one of Claims 1 to 4, wherein the solid material is obtained by melting and quenching the following precursors: ・ Li ２ S, ・ B ２ S ３ and / or both boron and sulfur, and ・B ２ O ３ The mixture can be obtained by melting and quenching, where the molar ratio of the precursors in the mixture before quenching is according to the general formula (II) xLi ２ S - yB ２ S ３ - zB ２ O ３ (II) (wherein 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 9, preferably in the range of 2 to 8, more preferably in the range of 4 to 6, x + y + z = 100), a solid material having a molar ratio such that a composition according to this formula is obtained.

6. The solid material according to Claim 5, wherein x is in the range of 64.2 to 65.8, preferably in the range of 64.5 to 65.5, more preferably in the range of 64.8 to 65.2, y is in the range of 29.2 to 30.8, preferably in the range of 29.5 to 30.5, more preferably in the range of 29.8 to 30.2, z is in the range of 4.2 to 5.8, preferably in the range of 4.5 to 5.5, more preferably in the range of 4.8 to 5.2, x + y + z = 100, a solid material.

7. x is about 65, y is about 30, z is about 5, the solid material according to Claim 6.

8. The solid material according to any one of Claims 1 to 7, wherein the solid material is a glassy solid.

9. The solid material has an ionic conductivity of at least 0.1 mS / cm, preferably at least 0.15 mS / cm, at 25°C and a thermal stability ΔT that exceeds 100°C, preferably exceeds 110°C, more preferably exceeds 112°C. ｘ and where ΔT ｘ = T ｘ − T ｇ and in the formula, T ｘ is the crystallization onset temperature determined by DSC, and T ｇ is the glass transition temperature determined by DSC. The solid material according to any one of claims 1 to 8.

10. A method for preparing a solid material, preferably the solid material according to any one of claims 1 to 9, comprising: (i) providing the following precursors: ・Li ２ S, ・ B ２ S ３ and / or both boron and sulfur, and ・B ２ O ３ and (ii) preparing a mixture comprising the precursor provided in step (i), wherein - the molar ratio of elements Li, S, B, and O in the mixture corresponds to the general formula (I) according to claims 1 to 4, or - the molar ratio of the precursor in the mixture corresponds to the general formula (II) according to claims 5 to 7; (iii) heat-treating the mixture prepared in step (ii) to obtain a melt; (iv) rapidly cooling the melt obtained in step (iii) to obtain the solid material, preferably the solid material according to any one of claims 1 to 9. **Claim 11** An electrochemical cell comprising the solid material according to any one of claims 1 to 9. **Claim 12** The electrochemical cell according to claim 11, wherein the cathode, anode, and / or separator comprises the solid material according to any one of claims 1 to 9. **Claim 13** The electrochemical cell according to claim 12, wherein the separator comprises the solid material according to any one of claims 1 to 9. **Claim 14** Use of the solid material according to any one of claims 1 to 9 as a solid electrolyte for an electrochemical cell. **Claim 15** The use according to claim 14, wherein the solid electrolyte functions as a separator.

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