Sulfide solid electrolyte glass ceramic and manufacturing method for same

Abstract

Provided is a sulfide solid electrolyte glass ceramic including lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms. In an X-ray diffraction measurement using CuKα rays, the diffraction angle (2θ) has peaks at 20.2° and 29.3°, a value (PA / PB) of an intensity ratio of a peak intensity (PA) of the peak appearing at 2θ = 20.2° to a peak intensity (PB) of the peak appearing at 2θ = 29.3° is set to greater than 1.0. As a result, this sulfide solid electrolyte glass ceramic has high ionic conductivity and improved water resistance. Provided also is a method for manufacturing the sulfide solid electrolyte glass ceramic.

Description

Sulfide solid electrolyte glass ceramics and manufacturing method thereof

[0001] The present invention relates to a sulfide solid electrolyte glass ceramic and a method for producing the same.

[0002] With the recent rapid spread of information-related devices and communication devices such as personal computers, video cameras, and mobile phones, the development of batteries to be used as their power sources has become increasingly important. Conventionally, batteries used for such applications have used electrolytes containing flammable organic solvents, but by making batteries all-solid-state, flammable organic solvents are not used in the battery, safety devices can be simplified, and manufacturing costs and productivity are excellent. Therefore, batteries in which the electrolyte is replaced with a solid electrolyte layer are being developed.

[0003] Sulfide solid electrolytes have been known as solid electrolytes used in solid electrolyte layers, and further improvement in the ionic conductivity of these sulfide solid electrolytes is desired. The ionic conductivity is determined by the types and composition ratios of raw materials used to manufacture the solid electrolyte, the crystalline form of the manufactured solid electrolyte, and other factors. For example, optimization of the crystalline form of sulfide solid electrolytes has been studied to improve their ionic conductivity (Patent Document 1).

[0004] JP 2014-89971 A

[0005] The present invention has been made in view of the above circumstances, and aims to provide a sulfide solid electrolyte glass ceramic having high ionic conductivity, an electrode composite and a lithium ion battery using the same, and a method for producing the sulfide solid electrolyte glass ceramic.

[0006] The sulfide solid electrolyte glass ceramic according to the present invention contains lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms, and in X-ray diffraction measurement using CuKα rays, has peaks at diffraction angles (2θ) of 20.2° and 29.3°, and the peak intensity (P Ａ ) and the peak intensity (P Ｂ ) intensity ratio value (P Ａ / P Ｂ ) is greater than 1.0;

[0007] The method for producing a sulfide solid electrolyte glass ceramic according to the present invention comprises: ２ S) and phosphorus sulfide (P ２ S ５ and treating the solid electrolyte (A) and a lithium halide by at least one method selected from stirring, mixing, and pulverization to obtain a solid electrolyte (B).

[0008] The electrode mixture according to the present invention is an electrode mixture comprising the sulfide solid electrolyte glass ceramics and an electrode active material,

[0009] The lithium ion battery according to the present invention is a lithium ion battery including at least one of the sulfide solid electrolyte glass ceramic and the electrode composite. In this specification, the peak position may fluctuate within a range of ±0.5°.

[0010] According to the present invention, it is possible to provide a sulfide solid electrolyte glass ceramic having high ionic conductivity, an electrode composite and a lithium ion battery using the same, and a method for producing the sulfide solid electrolyte glass ceramic.

[0011] FIG. 1 is a flow diagram illustrating an example of a manufacturing method of the present embodiment. FIG. 2 is a diagram illustrating a method for removing background and calculating the area of ​​the 20.2° peak of X-ray diffraction (XRD) in Example 1. FIG. 3 is a diagram illustrating a method for removing background and calculating the area of ​​the 29.3° peak of X-ray diffraction (XRD) in Example 1. FIG. 4 is a diagram illustrating a method for removing background and calculating the area of ​​the 20.2° peak of X-ray diffraction (XRD) in Comparative Example 1. FIG. 5 is a diagram illustrating a method for removing background and calculating the area of ​​the 29.3° peak of X-ray diffraction (XRD) in Comparative Example 1. FIG. 6 is a diagram illustrating a method for calculating crystallite size (X-ray diffraction (XRD) measurement). FIG. 7 is a diagram illustrating a method for calculating crystallite size (X-ray diffraction (XRD) measurement). FIG. 8 is an exposure test apparatus for evaluating water resistance. FIG. 9 is a result of X-ray diffraction (XRD) measurement of the solid electrolyte (A1) obtained in step (A) of Example 1. FIG. 10 is a result of X-ray diffraction (XRD) measurement of the crystalline solid electrolyte (A2) obtained in step (A) of Example 1. 1 shows the results of X-ray diffraction (XRD) measurement of the amorphous solid electrolyte (B1) obtained in step (B) of Example 1. 1 shows the results of X-ray diffraction (XRD) measurement of the sulfide solid electrolyte glass ceramics (1) obtained in step (B) of Example 1. 1 shows the results of X-ray diffraction (XRD) measurement of the sulfide solid electrolyte glass ceramics (C1) obtained in Comparative Example 1.

[0012] Hereinafter, an embodiment of the present invention (hereinafter, sometimes referred to as "the present embodiment") will be described. In this specification, the upper and lower limit values ​​of a range expressed as "greater than or equal to," "less than or equal to," and "to" can be arbitrarily combined, and the numerical values ​​in the examples can also be used as the upper and lower limit values.

[0013] (Findings Obtained by the Inventors to Achieve the Present Invention) As a result of intensive research to solve the above-mentioned problems, the inventors have found the following and completed the present invention. As described in Patent Document 1, sulfide solid electrolytes have a PS structure as the main skeleton. ４ ３－ It has been confirmed that a peak is observed at a specific position by XRD measurement. However, the ionic conductivity of the sulfide solid electrolyte obtained by this method needs further improvement.

[0014] The inventors have found that sulfide solid electrolyte glass ceramics have peaks at specific positions obtained by X-ray diffraction (XRD) measurement, and the peak intensity (P Ａ ) and the peak intensity (P Ｂ ) intensity ratio value (P Ａ / P Ｂ The inventors have found that the ionic conductivity increases when the value of the sulfide solid electrolyte glass ceramics is within a specific range. The inventors have also found that electrode composites and lithium ion batteries using these sulfide solid electrolyte glass ceramics have excellent properties, and that the sulfide solid electrolyte glass ceramics can be easily obtained in high yield by the above-mentioned production method.

[0015] The sulfide solid electrolyte glass ceramic has a peak at a specific position and a specific crystallite diameter in an X-ray diffraction (XRD) measurement, and Ａ / P Ｂ It has not been recognized until now that excellent ionic conductivity is obtained when the value of β is within a specific range. Furthermore, it has been found that the above-described method for producing sulfide solid electrolyte glass ceramics improves the ionic conductivity of sulfide solid electrolyte glass ceramics simply by changing the method for adding conventional raw materials. Furthermore, water resistance is improved, and batteries obtained therefrom have excellent irreversible capacity, making this embodiment an extremely excellent production method. Below, sulfide solid electrolyte glass ceramics according to first to eleventh aspects of this embodiment, methods for producing sulfide solid electrolyte glass ceramics according to twelfth and thirteenth aspects of this embodiment, an electrode composite according to a fourteenth aspect of this embodiment, and a lithium ion battery according to a fifteenth aspect of this embodiment are described.

[0016] The sulfide solid electrolyte glass ceramic according to the first aspect of the present embodiment contains lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms, and in an X-ray diffraction measurement using CuKα rays, the sulfide solid electrolyte glass ceramic has peaks at diffraction angles (2θ) of 20.2° and 29.3°, and the peak intensity (P Ａ ) and the peak intensity (P Ｂ) intensity ratio value (P Ａ / P Ｂ The measurement of peak intensity by XRD using CuKα radiation can be carried out, for example, by the method described in the Examples.

[0017] The sulfide solid electrolyte glass ceramics of the invention described in Patent Document 1 are noted to have a peak at a specific position in X-ray diffraction (XRD) measurement, but differ from the sulfide solid electrolyte glass ceramics according to the first aspect in that they do not have a peak at 2θ=29.3°. This means that the sulfide solid electrolyte glass ceramics of this embodiment contain a crystal structure different from that of the solid electrolyte described in Patent Document 1. The sulfide solid electrolyte glass ceramics according to the first aspect have a peak at a specific position and further have a peak intensity ratio value (P Ａ / P Ｂ ) is greater than 1.0, it has been found that the ionic conductivity is high.

[0018] The reason why the sulfide solid electrolyte glass ceramics according to the first aspect have excellent ionic conductivity is not clear. However, even if the atoms constituting the sulfide solid electrolyte glass ceramics are the same, the sulfide solid electrolyte glass ceramics will have different crystal structures depending on the content of the atoms and the production method. Among these, if a peak is present at a specific peak position in XRD measurement and the intensity ratio of the peak intensities is within a specific range, it is thought that the sulfide solid electrolyte glass ceramics will contain many crystal structures with high ionic conductivity.

[0019] As the crystallite diameter increases to 30 nm or more, the proportion of grain boundaries decreases. Since the diffusion of lithium ions is suppressed at the grain boundaries, the ionic conductivity of the sulfide solid electrolyte glass ceramic increases as the proportion of grain boundaries decreases. The crystallite diameter can be measured, for example, by the method described in the Examples.

[0020] The sulfide solid electrolyte glass ceramic according to the second aspect of the present embodiment is the same as that of the first aspect, wherein the peak area intensity (I Ａ) and the peak area intensity (I Ｂ ) intensity ratio value (I Ａ / I Ｂ The peak area intensity can be determined by XRD using CuKα radiation, and can be carried out, for example, by the method described in the Examples.

[0021] In addition to the first aspect, the sulfide solid electrolyte glass ceramic of this embodiment further has an intensity ratio value of peak area intensities (I Ａ / I Ｂ ) is preferably 0.78 or more, since it results in a sulfide solid electrolyte glass ceramic with improved ionic conductivity.

[0022] A sulfide solid electrolyte glass ceramic according to a third aspect of this embodiment is a sulfide solid electrolyte glass ceramic according to the first or second aspect, further having a peak at 2θ=23.6°. In addition to the first aspect, a sulfide solid electrolyte glass ceramic having a peak at 2θ=23.6° is preferable because it is a sulfide solid electrolyte glass ceramic with improved ionic conductivity.

[0023] A sulfide solid electrolyte glass ceramic according to a fourth aspect of this embodiment is a sulfide solid electrolyte glass ceramic according to any one of the first to third aspects, wherein the halogen atoms are iodine atoms. In addition to the first aspect, the sulfide solid electrolyte glass ceramic preferably contains iodine atoms, which further improves ionic conductivity. Furthermore, the inclusion of halogen atoms is also preferable, as it improves water resistance, as described below.

[0024] A sulfide solid electrolyte glass ceramic according to a fifth aspect of this embodiment is the sulfide solid electrolyte glass ceramic according to the fourth aspect, further containing bromine atoms as the halogen atoms. In addition to the fourth aspect, if the sulfide solid electrolyte glass ceramic further contains bromine atoms, the crystal structure is more likely to form a thiolicon region II crystal structure described below, which is preferable.

[0025] A sulfide solid electrolyte glass ceramic according to a sixth aspect of the present embodiment is the same as that of the fifth aspect, wherein the content of bromine atoms contained in the sulfide solid electrolyte glass ceramic (M Ｂｒ mol) and iodine atom content (M Ｉ mol) is M Ｂｒ / M Ｉ In addition to the first aspect, when the sulfide solid electrolyte glass ceramic contains bromine atoms and iodine atoms, M Ｂｒ / M Ｉ By satisfying the relationship of M≦1.00, the ionic conductivity is further improved and the water resistance, which will be described later, is also improved, which is preferable. Ｂｒ mol) and the iodine atom content (M Ｉ mol) can be measured, for example, by the method described in the Examples.

[0026] The sulfide solid electrolyte glass ceramic according to a seventh aspect of the present embodiment is, in any one of the first to sixth aspects, ３１ P determined from P-NMR measurement ２ S ６ ４－ The sulfide solid electrolyte glass ceramic has a phosphorus ratio of 7.5 mol % or less.

[0027] In the inventors' study, P ２ S ６ ４－ The ingredients are known to be easily hydrolyzed. ２ S ６ ４－ The component itself inhibits the ionic conduction of Li ions and also acts as a factor inhibiting the crystal growth of the solid electrolyte, and if this component is present in large amounts, the crystallite size may not be large enough. ２ S ６ ４－ When the phosphorus ratio is 7.5 mol % or less, the water resistance and ionic conductivity described later are improved, which is preferable. ２ S ６ ４－The component traps Li ions in the solid electrolyte and may accelerate battery deterioration. ２ S ６ ４－ By setting the phosphorus ratio of the components to 7.5 mol % or less, it is possible to expect improvement in oxidation characteristics when used in a battery, which is preferable. ３１ P determined from P-NMR measurement ２ S ６ ４－ The phosphorus ratio can be determined by, for example, the method described in the Examples.

[0028] The sulfide solid electrolyte glass ceramic according to an eighth aspect of the present embodiment is any one of the first to seventh aspects, wherein the sulfide solid electrolyte glass ceramic has a content of Li calculated from the content of each element in the raw materials. ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I1 Ｐ２Ｓ５ ) and the ratio (I1 Ｌｉ２Ｓ / I Ｐ２Ｓ５ ) is 2.60 or more and 3.30 or less.

[0029] In addition to the first embodiment, the Li ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I1 Ｐ２Ｓ５ ) ratio (I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ ) is within a specific range, the P impurity of the solid electrolyte ２ S ６ ４－ This is preferable because it results in a sulfide solid electrolyte glass ceramic with a low content of the component, and the ion conductivity and water resistance are improved. ２ A small amount of residual S also leads to a reduction in the amount of free sulfur atoms, which improves water resistance as described below and further suppresses irreversible capacity when used in a battery, which is therefore preferable. ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I1 Ｐ２Ｓ５) can be determined, for example, by the method described in the Examples.

[0030] The sulfide solid electrolyte glass ceramic according to a ninth aspect of the present embodiment is any one of the first to eighth aspects, wherein Li is measured using an inductively coupled plasma (ICP) optical emission spectrometer. ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I Ｐ２Ｓ５ ) and the ratio (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ ) is 2.60 or more and 3.30 or less.

[0031] Li measured using an inductively coupled plasma (ICP) optical emission spectrometer ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I Ｐ２Ｓ５ ) and the ratio (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ ) is within a specific range, similar to the eighth aspect, P, which is an impurity of the solid electrolyte, ２ S ６ ４－ This is preferable because it results in a sulfide solid electrolyte glass ceramic with a low content of the component, and the ion conductivity and water resistance are improved. ２ A small amount of residual S also leads to a reduction in the amount of free sulfur atoms, which improves water resistance as described below and further suppresses irreversible capacity when used in a battery, which is therefore preferable.

[0032] A sulfide solid electrolyte glass ceramic according to a tenth aspect of this embodiment is a sulfide solid electrolyte glass ceramic according to any one of the first to ninth aspects, wherein the ratio (content ratio) of the lithium atom content (mol), the phosphorus atom content (mol), the sulfur atom content (mol), and the halogen atom content (mol) is lithium atoms:phosphorus atoms:sulfur atoms:halogen atoms = (3.20-3.70):(0.70-1.30):(3.00-5.00):(0.20-0.70). In addition to the first aspect, by containing lithium atoms, phosphorus atoms, sulfur atoms, and halogen atoms in specific contents, ionic conductivity is further improved, which is preferable. The contents of lithium atoms, phosphorus atoms, sulfur atoms, and halogen atoms can be determined, for example, by the method described in the Examples.

[0033] A sulfide solid electrolyte glass ceramic according to an eleventh aspect of this embodiment is a sulfide solid electrolyte glass ceramic comprising a thiolisiconregion II crystal structure in any one of the first to tenth aspects. In addition to the first aspect, the sulfide solid electrolyte glass ceramic preferably comprises a thiolisiconregion II crystal structure, which further improves ionic conductivity.

[0034] The method for producing a sulfide solid electrolyte glass ceramic according to a twelfth aspect of the present embodiment includes the steps of: ２ S) and phosphorus sulfide (P ２ S ５ and treating the solid electrolyte (A) and a lithium halide with at least one method selected from stirring, mixing, and pulverization to obtain a solid electrolyte (B).

[0035] According to the twelfth aspect, the sulfide solid electrolyte glass ceramics according to the first to eleventh aspects can be obtained with high efficiency. That is, according to the twelfth aspect, a sulfide solid electrolyte glass ceramics with improved ionic conductivity can be produced. The conventional production method described in Patent Document 1, in which raw materials are all charged at once to synthesize a sulfide solid electrolyte, was unable to produce a sulfide solid electrolyte glass ceramics with high crystallinity and high ionic conductivity, which has peaks at 2θ = 20.2° and 29.3°.

[0036] In a twelfth aspect, the process of obtaining a solid electrolyte (A) is referred to as step (A), and the process of obtaining a solid electrolyte (B) from the solid electrolyte (A) is referred to as step (B). By synthesizing a sulfide solid electrolyte glass ceramic in at least two steps, a sulfide solid electrolyte glass ceramic exhibiting high crystallinity and high conductivity, with peaks at 2θ = 20.2° and 29.3°, was obtained. The reason for the improved crystallinity is believed to be as follows: By sufficiently reacting the raw materials in the synthesis of step (A) to reduce impurities and unnecessary skeletons related to performance degradation, and then synthesizing a solid electrolyte with few impurities in step (B), the impurities can be reduced, and the subsequent thermal crystallization is thought to improve the crystallinity and conductivity. In this embodiment, crystallinity refers to the property of generating crystallites in the sulfide solid electrolyte and / or the property of the crystallites contained in the sulfide solid electrolyte growing and becoming larger.

[0037] A thirteenth aspect of this embodiment relates to a method for producing a sulfide solid electrolyte glass ceramic, which is the method for producing a sulfide solid electrolyte glass ceramic according to the twelfth aspect, further comprising heating the solid electrolyte (A). By carrying out the step (B) after heating the solid electrolyte (A) as described below, the crystallite diameter of the sulfide solid electrolyte glass ceramic is increased, which is preferable. The increased crystallite diameter as described above is preferable because it increases ionic conductivity.

[0038] A method for producing a sulfide solid electrolyte glass ceramic according to a fourteenth aspect of this embodiment is the method for producing a sulfide solid electrolyte glass ceramic according to the twelfth or thirteenth aspect, further comprising heating the solid electrolyte (B). Heating the solid electrolyte (B) as described below is preferable because it increases the crystallite size of the sulfide solid electrolyte glass ceramic.

[0039] The method for producing a sulfide solid electrolyte glass ceramic according to a fifteenth aspect of this embodiment is the same as the twelfth to fourteenth aspects, further comprising the steps of: ３１ P determined from P-NMR measurement ２ S ６ ４－ The method for producing a sulfide solid electrolyte glass ceramic has a phosphorus ratio of 15.0 mol % or less.

[0040] As mentioned above, sulfide solid electrolyte glass ceramics have a main skeleton of PS ４ ３－ Other than that, P ２ S ６ ４－ and P ２ S ７ ４－ The solid electrolyte (B) also contains a secondary skeleton such as P. ２ S ６ ４－ In order to increase the ionic conductivity of sulfide solid electrolyte glass ceramics, P ２ S ６ ４－ A small phosphorus ratio is preferred. The solid electrolyte (A) and the solid electrolyte (B) are intermediates in the production of sulfide solid electrolyte glass ceramics, and will be described in detail later.

[0041] The solid electrolyte (A) also contains P ２ S ６ ４－ and P ２ S ７ ４－ The sub-skeleton is P ２ S ７ ４－ This is because, as described later in step (B), Li may be further added as needed.２ By adding S, P ２ S ７ ４－ Li ２ It reacts with S to form the main skeleton, PS. ４ ３－ In contrast, P ２ S ６ ４－ P.S. ４ ３－ The decomposition reaction into P is slow, which deteriorates the ionic conductivity in the solid electrolyte (B). ２ S ６ ４－ In order to reduce ２ S ６ ４－ The content is preferably small. ２ S ６ ４－ also deteriorates water resistance, ２ S ６ ４－ A low content is preferred.

[0042] As a result of intensive investigation in consideration of the above mechanism, in a method for producing a sulfide solid electrolyte glass ceramic according to a thirteenth aspect of the present embodiment, ４ P ２ S ７ and wherein the solid electrolyte (A) contains ３１ P measured by P-NMR ２ S ７ ４－ A method for producing a sulfide solid electrolyte glass ceramic having a phosphorus ratio of 20.0 mol % or more has been achieved. ２ S ６ ４－ The phosphorus ratio can be determined, for example, by the solid ３１ It is determined by P-NMR measurement.

[0043] An electrode composite according to a sixteenth aspect of the present embodiment is an electrode composite including the sulfide solid electrolyte glass ceramic according to any one of the first to eleventh aspects and an electrode active material. The sulfide solid electrolyte glass ceramic according to any one of the first to eleventh aspects has high ionic conductivity, and therefore, an electrode composite using the sulfide solid electrolyte glass ceramic has excellent ionic conductivity.

[0044] A lithium ion battery according to a seventeenth aspect of this embodiment is a lithium ion battery including at least one of the sulfide solid electrolyte glass ceramics according to any one of the first to eleventh aspects and the electrode composite according to the sixteenth aspect. Because the sulfide solid electrolyte glass ceramics and the electrode composite have excellent properties as described above, an electrode composite using these has excellent battery properties.

[0045] The sulfide solid electrolyte glass ceramics, the method for producing the sulfide solid electrolyte glass ceramics, the electrode mixture, and the lithium ion battery of this embodiment will be described in more detail below in accordance with the above-described embodiments.

[0046] [Sulfide Solid Electrolyte Glass Ceramics] The sulfide solid electrolyte glass ceramics of this embodiment contain lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms, and have peaks at 20.2° and 29.3° in X-ray diffraction (XRD) measurement using CuKα rays, and the peak intensity (P Ａ ) and the peak intensity (P Ｂ ) intensity ratio value (P Ａ / P Ｂ ) is required to be greater than 1.0 and the crystallite size is required to be 30 nm or more. Ａ / P Ｂ If the crystallite diameter is less than 30 nm, the desired ionic conductivity cannot be obtained. The sulfide solid electrolyte glass ceramics of this embodiment is preferably obtained by heating an amorphous sulfide solid electrolyte as described below.

[0047] In this specification, the term "sulfide solid electrolyte" refers to an electrolyte that maintains a solid state at 25°C under a nitrogen atmosphere, contains lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms, and has ionic conductivity attributable to lithium atoms.

[0048] The term "sulfide solid electrolyte" includes both crystalline sulfide solid electrolytes having a crystalline structure and amorphous sulfide solid electrolytes. In this specification, a crystalline sulfide solid electrolyte is a sulfide solid electrolyte in which peaks derived from the sulfide solid electrolyte are observed in the X-ray diffraction pattern in X-ray diffraction measurement, regardless of whether or not peaks derived from the raw materials of the sulfide solid electrolyte are present. That is, a crystalline sulfide solid electrolyte includes a crystalline structure derived from the sulfide solid electrolyte, and the crystalline structure may be partially or entirely derived from the sulfide solid electrolyte. Furthermore, as long as the crystalline sulfide solid electrolyte has the X-ray diffraction pattern described above, it may contain amorphous sulfide solid electrolyte in part, or it may not contain amorphous sulfide solid electrolyte. In fact, containing an amorphous component is preferable because it facilitates processing into batteries. Therefore, crystalline sulfide solid electrolytes include so-called glass ceramics obtained by heating an amorphous sulfide solid electrolyte above its crystallization temperature.

[0049] The sulfide solid electrolyte glass ceramics of this embodiment are crystalline sulfide solid electrolytes that may contain amorphous components. In this specification, the term "amorphous sulfide solid electrolyte" refers to an X-ray diffraction pattern in which a halo pattern with substantially no peaks is observed in X-ray diffraction measurement, regardless of whether peaks derived from the raw materials of the sulfide solid electrolyte or slight crystals inevitably formed during the isolation process of the amorphous sulfide solid electrolyte are present. Furthermore, the term "sulfide solid electrolyte glass ceramics" refers to a sulfide solid electrolyte in which a peak of a crystalline structure derived from the sulfide solid electrolyte and a halo pattern derived from the amorphous sulfide solid electrolyte are observed in the X-ray diffraction pattern in X-ray diffraction measurement.

[0050] In X-ray diffraction measurement using CuKα radiation, the sulfide solid electrolyte glass ceramic of this embodiment has peaks at diffraction angles (2θ) of 20.2° and 29.3°, and preferably also has a peak at 2θ = 23.6°. In addition to the peaks mentioned above, the sulfide solid electrolyte glass ceramic of this embodiment also has peaks near 2θ = 17.5°, 18.3°, 26.1°, 27.3°, and 30.0°, and it has been confirmed that there is a particularly strong correlation between the peak intensities of the peaks appearing at 20.2° and 29.3° and ionic conductivity.

[0051] The peak position and crystallite size in X-ray diffraction (XRD) measurement using CuKα radiation can be determined, for example, by the method described in the Examples. The peak intensity is the height of the peak top from the baseline in the X-ray diffraction pattern of the XRD measurement (diffraction intensity), and can be determined by the method described in the Examples. The peak position and analytical intensity can be determined from the height of the peak top at 2θ.

[0052] <P Ａ / P Ｂ The sulfide solid electrolyte glass ceramic of this embodiment contains halogen atoms in its structure, and the peak intensity (P Ａ ) and the peak intensity (P Ｂ ) has a different crystal structure. Ｂ It was found that the smaller the peak intensity, the higher the ionic conductivity. However, the peak intensity is a value that changes depending on the measurement conditions, etc. The inventors have Ａ / P Ｂ The intensity ratio is less susceptible to the influence of differences in measurement conditions, etc., and P Ａ / P ＢIt has been discovered that sulfide solid electrolyte glass ceramics with a value of greater than 1.0 have a high lithium ion transport number and high ionic conductivity. The crystal structure appearing at 2θ = 20.2° appears in compositions with a high iodine content, and the manufacturing method of this patent also provides high crystallinity and ionic conductivity. On the other hand, the crystal structure appearing at 2θ = 29.3° appears in compositions with a high bromine content, with a wide half-width peak and low crystallinity. Furthermore, an increase in this phase reduces the crystallinity of the crystal at 2θ = 20.2°. Changing the ratio of the halogens contained changes the ratio of the two crystals, resulting in a P Ａ / P Ｂ If P exceeds 1.0, the proportion of the highly conductive 2θ=20.2° crystalline phase increases, improving the crystallinity and, as a result, improving the ionic conductivity. Ａ / P Ｂ If the value is 1.0 or less, the desired ionic conductivity cannot be obtained.

[0053] To increase ionic conductivity, P Ａ / P Ｂ The lower limit of P is more preferably 1.1 or more, and even more preferably 1.5 or more. Ａ / P Ｂ Since the larger the value, the better, there is no particular upper limit, but the upper limit of P is usually 20.0 or less for sulfide solid electrolyte glass ceramics that can be manufactured. Ａ / P Ｂ can be calculated, for example, by the method described in the Examples.

[0054] (I Ａ / I Ｂ In order to increase the ionic conductivity of the sulfide solid electrolyte glass ceramics of this embodiment, the peak area intensity (I Ａ ) and the peak area intensity (I Ｂ ) intensity ratio value (I Ａ / I Ｂ ) is preferably 0.78 or more, more preferably 0.85 or more, and even more preferably 0.93 or more. There is no particular upper limit, but the upper limit of the sulfide solid electrolyte glass ceramics that can be produced is usually 10.0 or less. Ａ / I Ｂcan be calculated, for example, by the method described in the Examples.

[0055] The sulfide solid electrolyte glass ceramic of this embodiment includes a crystal structure having peaks at 2θ=approximately 20.2° and 29.3° as the main crystal, and also includes other crystal structures such as Li ３ P.S. ４ Crystal structure, Li ４ P ２ S ６ Crystal structure, Li ７ P.S. ６ Crystal structure, Li ７ P ３ S １１ Crystal structure, Li ７ P ２ S ８ X crystal structure, Li ４ P.S. ４ X crystal structure (X is a halogen element). Here, "near" means including measurement error and variations in measurement values ​​due to the measuring device, and means a range of ±0.5°. In other words, 2θ = 20.2° means 19.7° or more and 20.7° or less.

[0056] The sulfide solid electrolyte glass ceramics of this embodiment preferably includes a thiolicon region II type crystal structure in order to obtain higher ionic conductivity. Here, the "thiolicon region II type crystal structure" means a structure in which Li ４－ｘ Ge １－ｘ P ｘ S ４ Thio-LISICON Region II crystal structure, Li ４－ｘ Ge １－ｘ P ｘ S ４This indicates that the sulfide solid electrolyte glass ceramics of this embodiment has a crystal structure similar to the thio-lisicon region II type. Furthermore, the sulfide solid electrolyte glass ceramics of this embodiment may have the thio-lisicon region II type crystal structure, but from the viewpoint of obtaining higher ionic conductivity, it is preferable that the sulfide solid electrolyte glass ceramics have the thio-lisicon region II type crystal structure as the main crystal. In this specification, "having the main crystal" means that the proportion of the target crystal structure in the crystal structure is 80% or more, preferably 90% or more, and more preferably 95% or more. Furthermore, from the viewpoint of obtaining higher ionic conductivity, the sulfide solid electrolyte glass ceramics of this embodiment has a crystalline Li ３ P.S. ４ (β-Li ３ P.S. ４ ) is preferably not included.

[0057] In X-ray diffraction measurement using CuKα radiation, Li ３ P.S. ４ Diffraction peaks of the crystal structure appear, for example, at 2θ=17.5°, 18.3°, 26.1°, 27.3°, and 30.0°. ４ P ２ S ６ Diffraction peaks of the crystal structure appear, for example, at 2θ=16.9°, 27.1°, and 32.5°. ７ P.S. ６ Diffraction peaks of the crystal structure appear, for example, at 2θ=15.3°, 25.2°, 29.6°, and 31.0°. ７ P ３ S １１ Diffraction peaks of the crystal structure appear, for example, at 2θ=17.8°, 18.5°, 19.7°, 21.8°, 23.7°, 25.9°, 29.6°, and 30.0°, and Li ４－ｘ Ge １－ｘ P ｘ S ４ The diffraction peaks of the thio-LISICON Region II crystal structure appear, for example, at 2θ=20.1°, 23.9°, and 29.5°, and Li ４－ｘ Ge １－ｘ P ｘ S ４Diffraction peaks of a crystal structure similar to that of thio-LISICON Region II type appear, for example, at 2θ = 20.2 and 23.6°. Note that these peak positions may vary within a range of ±0.5°.

[0058] As described above, the sulfide solid electrolyte glass ceramics of this embodiment contains crystalline Li ３ P.S. ４ (β-Li ３ P.S. ４ 7 shows an example of X-ray diffraction measurement of the sulfide solid electrolyte glass ceramic of this embodiment. The sulfide solid electrolyte glass ceramic of this embodiment does not contain crystalline Li ３ P.S. ４ The diffraction peaks at 2θ=17.5° and 26.1° seen in the thiolicon region II crystal structure are not present, or even if they are present, they are extremely small peaks compared to the diffraction peaks of the thiolicon region II crystal structure.

[0059] The above Li ７ P.S. ６ The structural skeleton of the compound has the composition formula Li ７－ｘ P １－ｙ Si ｙ S ６ and Li ７＋ｘ P １－ｙ Si ｙ S ６ The crystal structure represented by the formula (x is -0.6 to 0.6, y is 0.1 to 0.6) is a cubic or orthorhombic crystal, preferably a cubic crystal, and in X-ray diffraction measurement using CuKα radiation, has peaks that appear mainly at 2θ=15.5°, 18.0°, 25.0°, 30.0°, 31.4°, 45.3°, 47.0°, and 52.0°. ７－ｘ－２ｙ P.S. ６－ｘ－ｙ Cl ｘ The crystal structure represented by (0.8≦x≦1.7, 0<y≦−0.25x+0.5) is preferably a cubic crystal, and in X-ray diffraction measurement using CuKα radiation, has peaks that appear mainly at 2θ=15.5°, 18.0°, 25.0°, 30.0°, 31.4°, 45.3°, 47.0°, and 52.0°. ７－ｘP.S. ６－ｘ Ha ｘ The crystal structure represented by the formula (Ha is Cl or Br, and x is preferably 0.2 to 1.8) is preferably a cubic crystal, and in X-ray diffraction measurement using CuKα radiation, has peaks that appear mainly at 2θ=15.5°, 18.0°, 25.0°, 30.0°, 31.4°, 45.3°, 47.0°, and 52.0°.

[0060] (Crystallite diameter) The crystallite diameter of the sulfide solid electrolyte glass ceramic of this embodiment must be 30 nm or more. As mentioned above, this is because high ionic conductivity cannot be obtained. From the viewpoint of improving ionic conductivity and water resistance, it is preferably 32 nm or more, more preferably 33 nm or more, even more preferably 35 nm or more, even more preferably 40 nm or more, even more preferably 70 nm or more, and even more preferably 76 nm or more. As will be described later, the crystallite diameter of the sulfide solid electrolyte glass ceramic can be further increased by crystallization after step (A), and in such cases, it is particularly preferable that it be 90 nm or more. There is no particular upper limit, but from the perspective of ease of production, ease of procurement, and ease of production of batteries, etc., it is preferably 300 nm or less, more preferably 250 nm or less, even more preferably 200 nm or less, even more preferably 180 nm or less, and even more preferably 160 nm or less.

[0061] The sulfide solid electrolyte glass ceramics of this embodiment contains lithium atoms, phosphorus atoms, sulfur atoms, and halogen atoms, and the halogen atoms are preferably at least one selected from chlorine atoms, bromine atoms, and iodine atoms. When only one halogen atom is contained, it is preferably a bromine atom or an iodine atom, and more preferably an iodine atom.

[0062] When two types of halogen atoms are contained, a combination of chlorine and bromine atoms, a combination of chlorine and bromine atoms, or a combination of bromine and iodine atoms is preferred, with a combination of bromine and iodine atoms being more preferred. This is preferred because it increases ionic conductivity. Furthermore, sulfide solid electrolyte glass ceramics are preferred because they contain iodine atoms, which improves water resistance.

[0063] The sulfide solid electrolyte glass ceramics of this embodiment preferably contains at least iodine atoms, and more preferably bromine atoms, in order to improve ionic conductivity and water resistance.

[0064] (M Ｂｒ / M Ｉ The content of bromine atoms contained in the sulfide solid electrolyte glass ceramics (M Ｂｒ mol) and iodine atom content (M Ｉ mol) is M Ｂｒ / M Ｉ ≦1.00, the ionic conductivity can be increased, which is preferable. Ｂｒ depends on the total number of moles of bromine atoms contained in the raw materials used in producing the sulfide solid electrolyte glass ceramics, and M Ｉ M depends on the total number of moles of iodine atoms contained in the raw materials used in producing the sulfide solid electrolyte glass ceramics. Ｂｒ / M Ｉ It was found that the ionic conductivity can be significantly changed by adjusting M Ｂｒ / M Ｉ If you reduce Ａ / P Ｂ It was found that M Ｂｒ / M Ｉ A small M is preferable because it results in high crystallinity, a large crystallite diameter, and high ionic conductivity, and furthermore, as the crystallinity increases, the water resistance described below improves, which is also preferable. Ｂｒ / M Ｉ is more preferably 0.80 or less, even more preferably 0.50 or less, and even more preferably 0.40 or less.

[0065] In addition, in order to increase the ionic conductivity, M Ｂｒ / M Ｉ However, when sulfide solid electrolyte glass ceramics contain a small amount of bromine atoms, the presence of bromine atoms smaller than iodine atoms in the crystal causes local distortion in the crystal structure, which is thought to improve the conduction probability of a part of the ion conduction path, and this is therefore preferable. Ｂｒ / M Ｉ is preferably 0 or more, more preferably greater than 0, even more preferably 0.05 or more, and even more preferably 0.08 or more. Ｂｒ and M Ｉ can be calculated from the content of each element in the raw material.

[0066] The sulfide solid electrolyte glass ceramic of this embodiment is a solid ３１ P determined from P-NMR measurement ２ S ６ ４－ The phosphorus ratio is preferably 7.5 mol % or less. ２ S ６ ４－ is easily hydrolyzed, and P ２ S ６ ４－ A small phosphorus ratio is preferable because it improves water resistance. In order to improve ionic conductivity and water resistance, it is preferably 5.5 mol% or less, more preferably 4.0 mol% or less, even more preferably 2.0 mol% or less, even more preferably 1.5 mol% or less, even more preferably 1.0 mol% or less, and even more preferably 0.8 mol% or less. ２ S ６ ４－ The lower the phosphorus ratio, the better, and there is no particular restriction on the lower limit, so long as it is substantially 0 mol % or more. "Substantially" means that 0 mol % also includes below the detection limit.

[0067] In the sulfide solid electrolyte glass ceramics of this embodiment, P ２ S ７ ４－The smaller the phosphorus ratio, the better from the viewpoint of the ionic conductivity of the sulfide solid electrolyte. The phosphorus ratio is preferably 20.0% or less, more preferably 10.0% or less, and even more preferably 8.0% or less, with the lower limit being preferably closer to 0%.

[0068] In this specification, the term "main skeleton" refers to a PS ４ ３－ Unit phosphorus ratio (PS ４ ３－ From the viewpoint of increasing the ionic conductivity of the sulfide solid electrolyte, it means that the PS ４ ３－ The phosphorus ratio is preferably 60.0% or more, more preferably 70.0% or more, and even more preferably 80.0% or more, and there is no particular upper limit, but the closer to 100%, the better.

[0069] In addition, in this specification, PS ４ ３－ Unit Ratio (PS ４ ３－ phosphorus ratio), P ２ S ７ ４－ Unit ratio (P ２ S ７ ４－ phosphorus ratio) and P ２ S ６ ４－ Unit ratio (P ２ S ６ ４－ phosphorus ratio) is ３１ P MAS NMR spectrum (solid ３１ P NMR spectrum) and waveform separation were performed. ４ ３－ Unit, P ２ S ７ ４－ Unit and P ２ S ６ ４－ It means the ratio of the area of ​​the unit peak to the total. ３１ The detailed conditions for measuring the P NMR spectrum are not particularly limited, and the measurement may be carried out, for example, under the conditions described in the Examples.

[0070] (I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ The sulfide solid electrolyte glass ceramic of this embodiment has a Li content calculated from the content of each element in the raw material. ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I1 Ｐ２Ｓ５ ) ratio (I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ ) is preferably 2.60 or more and 3.30 or less in order to improve ionic conductivity and water resistance, and from the viewpoint of improving ionic conductivity and water resistance, it is more preferably 2.70 or more and 3.20 or less, and even more preferably 2.90 or more and 3.10 or less.

[0071] (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ The sulfide solid electrolyte glass ceramic of this embodiment has a composition determined using an inductively coupled plasma (ICP) optical emission spectrometer as described below. ２ Molar fraction of S (I Ｌｉ２Ｓ ) and P ２ S ５ Molar fraction (I Ｐ２Ｓ５ ) ratio (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ ) is preferably 2.60 or more and 3.30 or less in order to improve ionic conductivity and water resistance, and from the viewpoint of improving ionic conductivity and water resistance, it is more preferably 2.70 or more and 3.20 or less, and even more preferably 2.90 or more and 3.10 or less. From the results of the examples described later, it is clear that the ratio (I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ ) and the ratio (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ ) is approximately equal to or less than 10%, further equal to or less than 9.5%, 7.5%, 5%, 3%, 1.5%, and 1%. Therefore, according to the manufacturing method of this embodiment described later, lithium sulfide (Li ２ S) and phosphorus sulfide (P ２ S ５), and further, it is understood that a sulfide solid electrolyte glass ceramic having high ionic conductivity can be obtained while effectively utilizing the solid electrolytes (A) and (B) obtained from raw materials containing these.

[0072] In the sulfide solid electrolyte glass ceramic of this embodiment, the ratio (mol) of the lithium atom content (mol), the phosphorus atom content (mol), the sulfur atom content (mol) and the halogen atom content (mol) (content ratio) is lithium atoms: phosphorus atoms: sulfur atoms: halogen atoms = (3.20 to 3.70): (0.70 to 1.30): (3.00 to 5.00): (0.20 to 0.70), which is preferable because it is easy to form a thiolicon region II crystal structure, (3.30 to 3.60): (0.80 to 1.20): (3.50 to 4.50): (0.30 to 0.60), more preferably (3.40 to 3.55): (0.90 to 1.10): (3.70 to 4.30): (0.40 to 0.55). These contents can be calculated from the content of each element in the raw materials.

[0073] The shape of the sulfide solid electrolyte glass ceramics of this embodiment is not particularly limited, but may be, for example, particulate. The average particle size (D ５０ The average particle size (D) can be, for example, in the range of 0.01 μm to 500 μm, or 0.1 to 200 μm. ５０ ) can be measured, for example, by a laser diffraction / scattering particle size distribution measuring device (for example, HORIBA, LA-950V2 model LA-950W2).

[0074] (Ionic Conductivity) The ionic conductivity of the sulfide solid electrolyte glass ceramics of this embodiment obtained by the manufacturing method of this embodiment is ４ ３－Due to the high phosphorus ratio, the electrical conductivity is extremely high, and can usually be 0.01 mS / cm or higher, more preferably 5.0 mS / cm or higher, even more preferably 5.4 mS / cm or higher, even more preferably 5.8 mS / cm or higher, excellently preferably 6.0 mS / cm or higher, even more excellently preferably 6.8 mS / cm or higher, and particularly preferably 7.2 mS / cm or higher.

[0075] Water resistance (H ２ The sulfide solid electrolyte glass ceramics of this embodiment is preferable because it exhibits high ionic conductivity and excellent water resistance. When the sulfide solid electrolyte comes into contact with moisture such as humidity in the air, a hydrolysis reaction proceeds, and therefore hydrogen sulfide (H ２ "Water resistance" means that the product will not be affected by moisture in the air. ２ It means the property of suppressing the generation of S. ２ The amount of S generated is preferably small. ２ If the amount of sulfur generated is less than 2.0 cc / g, there is no practical problem. It is more preferably 1.5 cc / g or less, even more preferably 1.0 cc / g or less, even more preferably 0.8 cc / g or less, and most preferably 0.5 cc / g or less. The lower limit is not particularly limited.

[0076] The manufacturing method of this embodiment will be described in more detail below in accordance with the above-described embodiment.

[0077] [Method for Producing Sulfide Solid Electrolyte Glass Ceramics] The method for producing the sulfide solid electrolyte glass ceramics of this embodiment includes the steps of: ２ S) and phosphorus sulfide (P ２ S ５ (a) treating the solid electrolyte (A) with at least one selected from stirring, mixing, and pulverization to obtain a solid electrolyte (A); and (b) treating the solid electrolyte (A) and a lithium halide with at least one selected from stirring, mixing, and pulverization to obtain a solid electrolyte (B).

[0078] According to the manufacturing method of this embodiment, a sulfide solid electrolyte glass ceramic having high ionic conductivity can be manufactured by a simple manufacturing method. Furthermore, the manufactured sulfide solid electrolyte glass ceramic has high water resistance, and a lithium ion battery using the same has excellent battery characteristics, which is preferable.

[0079] <Step (A)> The method for producing the sulfide solid electrolyte glass ceramics of this embodiment comprises the steps of: ２ S) and phosphorus sulfide (P ２ S ５ ) by at least one method selected from stirring, mixing, and pulverization to obtain a solid electrolyte (A) (sometimes referred to as step (A)), and more preferably, the solid electrolyte (A) is further heated to crystallize it. The method for producing a sulfide solid electrolyte glass ceramic of this embodiment differs from the method described in Patent Document 1 in that it produces the solid electrolyte (A). By passing through the solid electrolyte (A) in this way, P, which becomes an impurity in the solid electrolyte, can be reduced. ２ S ６ ４－ This is because the phosphorus ratio can be reduced, and can be further reduced by heating the solid electrolyte (A) as needed, making it possible to produce a solid electrolyte (B) with improved crystallinity. ２ S ６ ４－ Any manufacturing method that can reduce the phosphorus ratio may be used, and there are no particular limitations on the manufacturing method.

[0080] <Step (B)> The method for producing the sulfide solid electrolyte glass ceramics of this embodiment requires treating the solid electrolyte (A) and lithium halide by at least one method selected from stirring, mixing, and pulverization to obtain a solid electrolyte (B) (sometimes referred to as step (B)). Step (B) of this embodiment involves treating the solid electrolyte (A) obtained in step (A), lithium halide, and, if necessary, Li ２The solid electrolyte (B) is obtained by treating S with at least one method selected from stirring, mixing, and pulverization, which will be described later. In step (B), the solid electrolyte (A) may be taken out after the completion of step (A) and lithium halide may be added to the obtained solid electrolyte (A) for treatment, or lithium halide may be added after the completion of step (A) for treatment. From the viewpoint of not complicating the production process, it is preferable to add lithium halide to the treatment device used in step (A) after the completion of step (A) for treatment. Li ２ When S is used, it is preferably added simultaneously with or before or after the lithium halide. The lithium halide preferably contains at least lithium iodide (LiI), and more preferably contains lithium bromide (LiBr).

[0081] <Treatment> The treatments in step (A) and step (B) of this embodiment must be at least one selected from stirring, mixing, and pulverization. Stirring, mixing, and pulverization may be performed alone or in combination, but pulverization is preferred from the viewpoint of setting the particle size of the sulfide solid electrolyte within the range described below. The treatments in step (A) and step (B) may be the same or different, but are preferably the same. From the viewpoint of not complicating the production process, it is more preferable to perform them continuously using the same treatment device.

[0082] The treatment of this embodiment can be carried out using a mixer, a stirrer, a pulverizer, etc. This is because the raw materials can be mixed using a stirrer, and the raw materials are pulverized in a pulverizer, but are also mixed at the same time.

[0083] Examples of the stirrer or mixer include a mechanical stirring mixer that is equipped with stirring blades in a reaction vessel and can stir (also referred to as mixing by stirring or stirring and mixing). Examples of the mechanical stirring mixer include a high-speed stirring mixer and a double-arm mixer. Examples of the high-speed stirring mixer include a vertical-axis rotary mixer and a horizontal-axis rotary mixer, and either type of mixer may be used.

[0084] Examples of the shape of the stirring blade used in the mechanical stirring mixer include blade type, arm type, anchor type, paddle type, full zone type, ribbon type, multi-stage blade type, double arm type, shovel type, double-shaft blade type, flat blade type, C-type blade type, etc., and from the viewpoint of promoting the reaction of the raw materials more efficiently, the shovel type, flat blade type, C-type blade type, anchor type, paddle type, full zone type, etc. are preferred, with the anchor type, paddle type, and full zone type being more preferred.

[0085] When a mechanical stirring mixer is used, the rotation speed of the stirring blades can be adjusted appropriately depending on the volume of the fluid in the reaction vessel, the temperature, the shape of the stirring blades, etc., and is not particularly limited. However, it is usually sufficient to set the rotation speed at about 5 rpm or more and 400 rpm or less. From the viewpoint of more efficiently promoting the reaction of the raw materials, the rotation speed is preferably 10 rpm or more and 300 rpm or less, more preferably 15 rpm or more and 250 rpm or less, and even more preferably 20 rpm or more and 200 rpm or less.

[0086] The temperature conditions when mixing is performed using a mixer are not particularly limited, and are, for example, usually −30 to 120° C., preferably −10 to 100° C., more preferably 0 to 80° C., and even more preferably 10 to 60° C. The mixing time is usually 0.1 to 500 hours, and from the viewpoint of achieving a more uniform dispersion state of the raw materials and promoting the reaction, is preferably 1 to 450 hours, more preferably 10 to 425 hours, even more preferably 20 to 400 hours, and still more preferably 30 to 375 hours.

[0087] The method of mixing with pulverization using a pulverizer has traditionally been adopted as a mechanical milling method. As the pulverizer, for example, a media-type pulverizer using a pulverization medium can be used. Media-type pulverizers are broadly classified into container-driven pulverizers and media-agitation pulverizers. Examples of container-driven pulverizers include agitation tanks, pulverization tanks, or combinations thereof, such as ball mills and bead mills. Examples of media-agitation pulverizers include impact pulverizers such as cutter mills, hammer mills, and pin mills; tower-type pulverizers such as tower mills; agitation tank pulverizers such as attritors, aquamizers, and sand grinders; flow-through tank pulverizers such as Viscomill and pearl mills; flow-through pipe pulverizers; annular pulverizers such as Coball mills; continuous dynamic pulverizers; and single- or multi-shaft kneaders. Among these, considering the ease of adjusting the particle size of the resulting sulfide, the ball mill or bead mill exemplified as a container-driven pulverizer is preferred.

[0088] These pulverizers can be appropriately selected depending on the desired scale, etc. For relatively small scales, container-driven pulverizers such as ball mills and bead mills can be used, while for large scales or mass production, other types of pulverizers may be used.

[0089] Furthermore, as will be described later, when the mixture is in a liquid state involving a liquid such as a solvent or in a slurry state during mixing, a wet mill that can handle wet milling is preferred. Typical examples of wet mills include wet bead mills, wet ball mills, and wet vibration mills. Wet bead mills that use beads as milling media are preferred because they allow for free adjustment of milling conditions and are easily adaptable to smaller particle sizes. Dry mills, such as dry media mills (e.g., dry bead mills, dry ball mills, dry planetary ball mills, and dry vibration mills) and dry non-media mills (e.g., jet mills), can also be used.

[0090] Furthermore, when the material to be mixed is in a liquid state or a slurry state, a flow-through mill that can perform a circulation operation to circulate the material as needed can also be used. Specifically, a mill that circulates the material between a mill (pulverizing mixer) that pulverizes the slurry and a temperature holding tank (reaction vessel) can be used.

[0091] The size of the beads or balls used in the ball mill or bead mill may be appropriately selected depending on the desired particle size, processing amount, etc. For example, the diameter of the beads is usually 0.05 mmφ or more, preferably 0.1 mmφ or more, more preferably 0.3 mmφ or more, with the upper limit being usually 5.0 mmφ or less, preferably 3.0 mmφ or less, more preferably 2.0 mmφ or less. The diameter of the balls is usually 2.0 mmφ or more, preferably 2.5 mmφ or more, more preferably 3.0 mmφ or more, with the upper limit being usually 30.0 mmφ or less, preferably 20.0 mmφ or less, more preferably 15.0 mmφ or less. Examples of materials include metals such as stainless steel, chrome steel, and tungsten carbide; ceramics such as zirconia and silicon nitride; and minerals such as agate.

[0092] Furthermore, when a ball mill or a bead mill is used, the rotation speed varies depending on the scale of the treatment and cannot be generally determined, but is usually 10 rpm or more, preferably 20 rpm or more, and more preferably 50 rpm or more, and the upper limit is usually 1,000 rpm or less, preferably 900 rpm or less, more preferably 800 rpm or less, and even more preferably 700 rpm or less.

[0093] The grinding time in this case cannot be generalized because it varies depending on the scale of the treatment, but is usually 5 hours or more, preferably 10 hours or more, more preferably 20 hours or more, and even more preferably 30 hours or more, with the upper limit being usually 300 hours or less, preferably 200 hours or less, and more preferably 100 hours or less.

[0094] By selecting the size and material of the medium (beads, balls) used, the rotor rotation speed, time, etc., mixing, stirring, pulverization, and combinations of these processes can be performed, and the particle size, etc. of the resulting sulfide can be adjusted.

[0095] (Solvent) When mixing the raw materials, a solvent may be added to the raw materials and mixed in. As the solvent, various solvents widely known as organic solvents may be used.

[0096] As the solvent, a wide variety of solvents that have conventionally been used in the production of solid electrolytes can be used, and examples thereof include hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents.

[0097] Examples of aliphatic hydrocarbons include hexane, pentane, 2-ethylhexane, heptane, octane, decane, undecane, dodecane, and tridecane. Examples of alicyclic hydrocarbons include cyclohexane and methylcyclohexane. Examples of aromatic hydrocarbon solvents include benzene, toluene, xylene, mesitylene, ethylbenzene, tert-butylbenzene, trifluoromethylbenzene, and nitrobenzene.

[0098] In addition to the hydrocarbon solvents, examples of the solvent include solvents containing hetero elements such as nitrogen, oxygen, sulfur, halogen, etc. Preferred examples of such solvents include ether solvents and ester solvents containing oxygen as a hetero element, as well as alcohol solvents, aldehyde solvents, and ketone solvents.

[0099] Preferred examples of the ether solvent include aliphatic ethers such as dimethyl ether, diethyl ether, tert-butyl methyl ether, dimethoxymethane, dimethoxyethane, diethylene glycol dimethyl ether (diglyme), triethylene oxide glycol dimethyl ether (triglyme), diethylene glycol, and triethylene glycol; alicyclic ethers such as ethylene oxide, propylene oxide, tetrahydrofuran, tetrahydropyran, dimethoxytetrahydrofuran, cyclopentyl methyl ether, and dioxane; heterocyclic ethers such as furan, benzofuran, and benzopyran; and aromatic ethers such as methyl phenyl ether (anisole), ethyl phenyl ether, dibenzyl ether, and diphenyl ether.

[0100] Preferred examples of the ester solvent include methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, and isopropyl acetate; aliphatic esters such as methyl propionate, ethyl propionate, dimethyl oxalate, diethyl oxalate, dimethyl malonate, diethyl malonate, dimethyl succinate, and diethyl succinate; alicyclic esters such as methyl cyclohexanecarboxylate, ethyl cyclohexanecarboxylate, and dimethyl cyclohexanedicarboxylate; heterocyclic esters such as methyl pyridinecarboxylate, methyl pyrimidinecarboxylate, acetolactone, propiolactone, butyrolactone, and valerolactone; and aromatic esters such as methyl benzoate, ethyl benzoate, dimethyl phthalate, diethyl phthalate, butyl benzyl phthalate, dicyclohexyl phthalate, trimethyl trimellitate, and triethyl trimellitate.

[0101] Preferred examples of the solvent include alcohol-based solvents such as ethanol and butanol; aldehyde-based solvents such as formaldehyde, acetaldehyde, and dimethylformamide; and ketone-based solvents such as acetone and methyl ethyl ketone. Examples of the solvent containing a nitrogen element as a hetero element include solvents having a nitrogen-containing group such as an amino group, an amide group, a nitro group, and a nitrile group. These can also be used as complexing agents for converting the solid electrolyte into a complex.

[0102] Preferred examples of solvents having an amino group include aliphatic amines such as ethylenediamine, diaminopropane, dimethylethylenediamine, diethylethylenediamine, dimethyldiaminopropane, tetramethyldiaminomethane, tetramethylethylenediamine (TMEDA), and tetramethyldiaminopropane (TMPDA); alicyclic amines such as cyclopropanediamine, cyclohexanediamine, and bisaminomethylcyclohexane; heterocyclic amines such as isophoronediamine, piperazine, dipiperidylpropane, and dimethylpiperazine; and aromatic amines such as phenyldiamine, tolylenediamine, naphthalenediamine, methylphenylenediamine, dimethylnaphthalenediamine, dimethylphenylenediamine, tetramethylphenylenediamine, and tetramethylnaphthalenediamine. Preferred examples of solvents containing a nitrogen element include dimethylformamide, acetonitrile, acrylonitrile, and nitrobenzene.

[0103] Preferred examples of solvents containing a halogen element as a hetero element include dichloromethane, chlorobenzene, trifluoromethylbenzene, chlorobenzene, chlorotoluene, bromobenzene, etc. Preferred examples of solvents containing a sulfur element include dimethyl sulfoxide, carbon disulfide, etc.

[0104] When a solvent is used, the amount of solvent used is preferably 100 mL or more, more preferably 500 mL or more, even more preferably 1 L or more, still more preferably 2 L or more, and still more preferably 4 L or more, per 1 kg of the total amount of raw materials, and the upper limit is preferably 50 L or less, more preferably 20 L or less, even more preferably 15 L or less, and still more preferably 12 L or less. When the amount of solvent used is within the above range, the raw materials can be reacted efficiently.

[0105] (Drying) When mixing is performed using a solvent, the method may include drying the fluid (usually a slurry) obtained by mixing after the mixing. When a complexing agent is used as a solvent, the sulfide is obtained by removing the complexing agent from a complex containing the complexing agent. When a complexing agent and a solvent are used in combination, the complexing agent is removed from a complex containing the complexing agent and the solvent is removed. When a solvent other than the complexing agent is used, the solvent is removed. The obtained sulfide can be obtained by drying a PS ４ ３－ It has a structure of a solid electrolyte such as a unit, and exhibits ionic conductivity due to alkali metal elements such as lithium and sodium.

[0106] The fluid obtained by mixing can be dried at a temperature depending on the type of solvent. For example, drying can be performed at a temperature equal to or higher than the boiling point of the complexing agent. Furthermore, drying can be performed under reduced pressure (vacuum drying) using a vacuum pump or the like at a temperature typically between 5 and 100°C, preferably between 10 and 85°C, more preferably between 15 and 70°C, and even more preferably around room temperature (23°C) (for example, about room temperature ±5°C), thereby volatilizing the complexing agent and any solvent used as needed.

[0107] Drying may be performed by filtering the fluid using a glass filter or the like, by solid-liquid separation by decantation, or by solid-liquid separation using a centrifuge or the like. When a solvent other than a complexing agent is used, the sulfide is obtained by solid-liquid separation. When a complexing agent is used as the solvent, after solid-liquid separation, drying is performed under the above-mentioned temperature conditions to remove the complexing agent incorporated into the complex.

[0108] Specifically, solid-liquid separation can be easily performed by decantation, in which a fluid is transferred to a container, and after the sulfide (or a complex when a complexing agent is contained (which can also be called a sulfide precursor)) is precipitated, the complexing agent and solvent that form a supernatant are removed, or by filtration using, for example, a glass filter with a pore size of about 10 to 200 μm, preferably 20 to 150 μm.

[0109] Drying may be carried out after mixing and before the hydrogen treatment described below, or may be carried out after the hydrogen treatment.

[0110] (Li ２ S and P ２ S ５ In the manufacturing method of this embodiment, Li ２ S (lithium sulfide) and P ２ S ５ (diphosphorus pentasulfide) must be used.

[0111] Li used in this embodiment ２ Preferably, S is a particle. ２ Average particle size of S particles (D ５０ ) is preferably 10 μm or more and 2000 μm or less, more preferably 30 μm or more and 1500 μm or less, and even more preferably 50 μm or more and 1000 μm or less. ５０ ) is the particle size at which the particle size distribution curve is accumulated from the smallest particle size to the 50% of the total particle size, and the volume distribution is the average particle size that can be measured using, for example, a laser diffraction / scattering particle size distribution measuring device. ２ S ５ Regarding Li ２ It is preferable that the average particle size of the S particles is about the same as that of the Li particles. ２ Preferably, the average particle size is in the same range as that of the S particles.

[0112] In this embodiment, Li ２ S is added in step (A) and step (B), and P ２ S ５ is added in step (A). In step (A), P in the solid electrolyte (A) ２ S ７ ４－ In order to optimize the content of Li and prepare a sulfide solid electrolyte glass ceramic with high ionic conductivity, ２ For 1.00 mole of S, ２ S ５It is preferable to use 0.34 mol or more, more preferably 0.38 mol or more, and even more preferably 0.40 mol or more, and it is preferable to use 0.70 mol or less, more preferably 0.60 mol or less, and even more preferably 0.55 mol or less.

[0113] In this embodiment, in all steps including step (A) and step (B), the sulfide solid electrolyte glass ceramic is PS ４ ３－ The main skeleton is P in the sulfide solid electrolyte. ２ S ６ ４－ From the viewpoint of reducing the phosphorus ratio and achieving high ionic conductivity, the Li ２ For 1.00 mole of S, ２ S ５ It is preferable to use 0.10 mol or more, more preferably 0.20 mol or more, and even more preferably 0.30 mol or more, and it is preferable to use 0.50 mol or less, more preferably 0.40 mol or less, and even more preferably 0.35 mol or less.

[0114] In this embodiment, Li is used in at least step (A) and step (B). ２ Add S. P in sulfide solid electrolyte ２ S ６ ４－ From the viewpoint of reducing the phosphorus ratio and achieving high ionic conductivity, the Li ２ Li in step (B) for 1.00 mole of S ２ S is preferably used in an amount of 0.10 mol or more, more preferably 0.20 mol or more, and even more preferably 0.25 mol or more, and is preferably used in an amount of 0.80 mol or less, more preferably 0.70 mol or less, and even more preferably 0.65 mol or less.

[0115] Li ２ S and P ２ S ５ Although commercially available products can be used, those prepared by the methods described in the Examples may also be used. ２From the viewpoint of improving the ionic conductivity of the sulfide solid electrolyte glass ceramics, S preferably has a purity of 95% by mass or more, more preferably 98% by mass or more, and P ２ S ５ Is, P ４ S １０ From the viewpoint of improving the ionic conductivity of the sulfide solid electrolyte, the purity is preferably 95% by mass or more, and more preferably 98% by mass or more.

[0116] (Lithium Halide) In this embodiment, in order to obtain a sulfide solid electrolyte glass ceramic having high ionic conductivity, it is necessary to further add lithium halide in step (B) to introduce halogen atoms into the sulfide solid electrolyte. The lithium halide is preferably at least one selected from lithium chloride, lithium bromide, and lithium iodide, and more preferably a combination of lithium chloride and lithium bromide, or a combination of lithium bromide and lithium iodide. The amount of lithium halide used may be any amount as long as it satisfies the above-mentioned preferred compounding ratio (molar ratio) of lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms.

[0117] (Solid electrolyte (A)) The solid electrolyte (A) is a solid electrolyte obtained in step (A), and is a PS ４ ３－ , or P ２ S ７ ４－ The sulfide solid electrolyte preferably has a main skeleton of PS ４ ３－ It is more preferable that the sulfide solid electrolyte has the following main skeleton.

[0118] In this specification, the term "main skeleton" refers to a PS ４ ３－ Unit phosphorus ratio (PS ４ ３－ From the viewpoint of increasing the ionic conductivity of the sulfide solid electrolyte, it means that the PS ４ ３－The fraction is preferably 60.0% or more, more preferably 70.0% or more, and even more preferably 80.0% or more. There is no particular upper limit, and the closer to 100%, the better. However, from the viewpoint of achieving both ease of production and high ionic conductivity, the fraction is preferably 99.5% or less, more preferably 98.0% or less, and even more preferably 95.0% or less.

[0119] The solid electrolyte (A) is P ２ S ７ ４－ It is preferable that the amount of Li used as a raw material is small. ２ S and P ２ S ５ , the target PS ４ ３－ , and P ２ S ６ ４－ Among these, P ２ S ６ ４－ If the content of in the sulfide solid electrolyte increases, the ionic conductivity decreases, so it is preferable to reduce the content of.

[0120] In step (B), Li ４ P ２ S ７ The solid electrolyte (A) further contains Li ２ By adding S and lithium halide to obtain a sulfide solid electrolyte, P contained in the sulfide solid electrolyte glass ceramics can be reduced. ２ S ６ ４－ Therefore, from the viewpoint of improving the ionic conductivity of the sulfide solid electrolyte glass ceramics, the ratio of phosphorus in the solid electrolyte (A) can be reduced. ３１ P measured by P-NMR ２ S ７ ４－ The phosphorus ratio is preferably 20.0 mol % or more, more preferably 30.0 mol % or more, and even more preferably 35.0 mol % or more, based on the total amount of the solid electrolyte (A). There is no particular upper limit, but when the treatment in step (A) is performed, PS ４ ３－Therefore, the content is preferably 95.0 mol % or less, more preferably 90.0 mol % or less, and even more preferably 80.0 mol % or less.

[0121] The solid electrolyte (A) may be an amorphous sulfide solid electrolyte or a crystalline sulfide solid electrolyte, but a crystalline sulfide solid electrolyte is preferred because the crystallite diameter of the sulfide solid electrolyte glass ceramics becomes large.

[0122] (Solid Electrolyte (B)) The solid electrolyte (B) obtained in this embodiment is a product of the step (B) and is a production intermediate of a sulfide solid electrolyte glass ceramic. It contains lithium atoms, sulfur atoms, and phosphorus atoms, and is a PS ４ ３－ is preferably the main skeleton.

[0123] The solid electrolyte (B) may be a crystalline sulfide solid electrolyte or an amorphous sulfide solid electrolyte. If the solid electrolyte (B) is a crystalline sulfide solid electrolyte, it can be used as a sulfide solid electrolyte glass ceramic, but it can also be further heated to promote crystallization. If the solid electrolyte (B) is an amorphous sulfide solid electrolyte, it can be made into a sulfide solid electrolyte glass ceramic by heating (crystallization) as described below.

[0124] The solid electrolyte (B) contains a halogen atom, and a representative example of the solid electrolyte containing a halogen atom is Li. ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -LiCl, Li ２ S-P ２ S ５ - LiBr, Li ２ S-P ２ S ５ -LiI-LiBr, etc., solid electrolytes composed of lithium sulfide, phosphorus sulfide, and lithium halide; and solid electrolytes further containing other atoms such as oxygen atoms and silicon atoms, for example, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li２ S-SiS ２ -P ２ S ５ In order to obtain higher ionic conductivity, a solid electrolyte such as Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -LiCl, Li ２ S-P ２ S ５ - LiBr, Li ２ S-P ２ S ５ A solid electrolyte composed of lithium sulfide, phosphorus sulfide, and a lithium halide, such as —LiI—LiBr, is preferred. The types of atoms constituting the solid electrolyte (B) can be confirmed, for example, by an ICP emission spectrometer.

[0125] When the solid electrolyte (B) of this embodiment is an amorphous sulfide solid electrolyte, the solid of the solid electrolyte (B) ３１ P determined from P-NMR measurement ２ S ６ ４－ The phosphorus ratio is preferably 15.0 mol% or less in order to improve ionic conductivity and water resistance, more preferably 10.0 mol% or less in terms of improving ionic conductivity and water resistance, and even more preferably 7.0 mol% or less. ２ S ６ ４－ Since it is preferable that the polymer does not contain any of these elements in order to improve ionic conductivity and water resistance, the lower limit is not particularly limited.

[0126] The solid electrolyte (B) of this embodiment may be heated as needed. ３１ P determined from P-NMR measurement ２ S ６ ４－ The phosphorus ratio is preferably 7.5 mol % or less. ２ S ６ ４－ is easily hydrolyzed, and P ２ S ６ ４－A small phosphorus ratio is preferable because it improves water resistance. In order to improve ionic conductivity and water resistance, it is preferably 5.5 mol% or less, more preferably 4.0 mol% or less, even more preferably 2.0 mol% or less, even more preferably 1.5 mol% or less, even more preferably 1.0 mol% or less, and even more preferably 0.8 mol% or less. ２ S ６ ４－ The lower the phosphorus ratio, the better, and there is no particular restriction on the lower limit, as long as it is substantially 0 mol% or more. "Substantially" means that 0 mol% also includes below the detection limit. The solid electrolyte (B) after heating may be the sulfide solid electrolyte glass ceramic of this embodiment, and may further be pulverized as necessary to form a sulfide solid electrolyte glass ceramic.

[0127] The solid electrolyte (B) obtained in this embodiment contains at least Li ２ S-P ２ S ５ When Li ２ S and P ２ S ５ In order to obtain a higher ionic conductivity, the molar ratio of Li to Li is preferably 65 to 85:15 to 35, more preferably 70 to 80:20 to 30, and even more preferably 72 to 78:22 to 28. ２ S-P ２ S ５ -LiI-LiBr, Li ２ S and P ２ S ５ The total content of lithium bromide and lithium iodide is preferably 60 to 95 mol%, more preferably 65 to 90 mol%, and even more preferably 70 to 85 mol%. The ratio of lithium bromide to the total of lithium bromide and lithium iodide is preferably 1 to 99 mol%, more preferably 20 to 90 mol%, even more preferably 40 to 80 mol%, and particularly preferably 50 to 70 mol%.

[0128] In the solid electrolyte (B) obtained in this embodiment, the compounding ratio (molar ratio) of lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms is preferably 1.0 to 1.8:1.0 to 2.0:0.1 to 0.8:0.01 to 0.6, more preferably 1.1 to 1.7:1.2 to 1.8:0.2 to 0.6:0.05 to 0.5, and even more preferably 1.2 to 1.6:1.3 to 1.7:0.25 to 0.5:0.08 to 0.4. Further, when bromine and iodine are used in combination as halogen atoms, the compounding ratio (molar ratio) of lithium atoms, sulfur atoms, phosphorus atoms, bromine, and iodine is preferably 1.0 to 1.8: 1.0 to 2.0: 0.1 to 0.8: 0.01 to 0.3: 0.01 to 0.3, more preferably 1.1 to 1.7: 1.2 to 1.8: 0.2 to 0.6: 0.02 to 0.25: 0.02 to 0.25, more preferably 1.2 to 1.6: 1.3 to 1.7: 0.25 to 0.5: 0.03 to 0.2: 0.03 to 0.2, and even more preferably 1.35 to 1.45: 1.4 to 1.7: 0.3 to 0.45: 0.04 to 0.18: 0.04 to 0.18. By setting the compounding ratio (molar ratio) of lithium atoms, sulfur atoms, phosphorus atoms, and halogen atoms within the above range, it becomes easier to obtain a sulfide solid electrolyte glass ceramic having a thiolisiconregion II type crystal structure described later and higher ionic conductivity.

[0129] The shape of the solid electrolyte (B) is not particularly limited, but may be, for example, particulate. The average particle diameter (D ５０ ) can be, for example, in the range of 0.01 μm to 500 μm, or 0.1 to 200 μm.

[0130] The exothermic peak of the sulfide solid electrolyte glass ceramic of this embodiment is preferably 120°C or higher and 300°C or lower, more preferably 150°C or higher and 250°C or lower, and even more preferably 170°C or higher and 220°C or lower.

[0131] In the sulfide solid electrolyte glass ceramics of this embodiment, when a differential thermal analysis (DTA) of the solid electrolyte (B), which is a production intermediate, is performed, the half width of the exothermic peak that first appears at a temperature of 130°C or higher during the temperature rise process is preferably 8.0°C or less, since this improves ion conductivity and water resistance, more preferably 7.0°C or less, and even more preferably 6.5°C or less.

[0132] (Heating) The production method of this embodiment preferably includes at least one of further heating the solid electrolyte (A) and further heating the solid electrolyte (B). To obtain the solid electrolyte (A) that is a crystalline sulfide solid electrolyte (hereinafter also referred to as the crystalline solid electrolyte (A)) or the sulfide solid electrolyte glass ceramic, the solid electrolyte (A) that is an amorphous sulfide solid electrolyte (hereinafter also referred to as the amorphous solid electrolyte (A)) or the solid electrolyte (B) that is an amorphous sulfide solid electrolyte (hereinafter also referred to as the amorphous solid electrolyte (B)) may be obtained and then heated.

[0133] More specifically, the solid electrolyte (A) obtained in step (A) may be heated to form a crystalline solid electrolyte (A), which may then be used as a raw material in step (B), or the solid electrolyte (B) obtained in step (B) may be heated after step (B) to form a sulfide solid electrolyte glass ceramic. Heating the solid electrolyte (A) obtained in step (A) to form a crystalline solid electrolyte (A) and then performing step (B) is preferred because it increases the crystallite size of the sulfide solid electrolyte glass ceramic.

[0134] When the amorphous solid electrolyte (B) is heated to obtain a sulfide solid electrolyte glass ceramic, the heating temperature may be determined depending on the structure of the sulfide solid electrolyte glass ceramic. Specifically, the amorphous solid electrolyte (B) is subjected to differential thermal analysis (DTA) using a differential thermal analyzer (DTA) at a temperature increase of 10°C / min. The temperature is preferably 5°C or more lower, more preferably 7°C or more lower, and even more preferably 10°C or more lower than the peak top temperature of the exothermic peak observed on the lowest temperature side of 130°C or higher. There is no particular restriction on the lower limit, but the temperature is preferably within 30°C on the lower side, more preferably within 25°C on the lower side. By using such a temperature range, the sulfide solid electrolyte glass ceramic can be obtained more efficiently and reliably.

[0135] When the amorphous solid electrolyte (A) is heated to obtain the crystalline solid electrolyte (A), differential thermal analysis (DTA) is performed using a differential thermal analyzer (DTA) at a temperature increase rate of 10°C / min, and the heat treatment is performed near the top of the exothermic peak. The preferred heat treatment temperature is in the range of -50°C to 100°C, preferably -30°C to 80°C, and more preferably -15°C to 65°C, starting from the temperature of the top of the exothermic peak.

[0136] The heating temperature for obtaining the crystalline sulfide solid electrolyte (A) or sulfide solid electrolyte glass ceramics cannot be generally specified because it varies depending on the structure of the crystalline sulfide solid electrolyte (A) or sulfide solid electrolyte glass ceramics to be obtained. However, it is usually preferably 130°C or higher, more preferably 135°C or higher, and even more preferably 140°C or higher. There is no particular upper limit, but it is preferably 350°C or lower, more preferably 330°C or lower, and even more preferably 320°C or lower.

[0137] The heating time is not particularly limited as long as the desired crystalline solid electrolyte (A) or sulfide solid electrolyte glass ceramics can be obtained, but is preferably, for example, 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and even more preferably 1 hour or more. The upper limit of the heating time is not particularly limited, but is preferably 24 hours or less, more preferably 10 hours or less, even more preferably 5 hours or less, and even more preferably 3 hours or less.

[0138] Furthermore, heating is preferably carried out in an inert gas atmosphere (e.g., a nitrogen atmosphere or an argon atmosphere) or a reduced pressure atmosphere (particularly in a vacuum), as this can prevent deterioration (e.g., oxidation) of the product. The heating method is not particularly limited, and examples thereof include methods using a hot plate, a vacuum heating device, an argon gas atmosphere furnace, and a calcination furnace. Furthermore, industrially, a horizontal dryer or a horizontal vibration fluidized dryer having a heating means and a feed mechanism can also be used, and the method may be selected depending on the amount of heat to be processed.

[0139] (Crushing) This embodiment preferably further includes crushing the solid electrolyte (A), the solid electrolyte (B), or the sulfide solid electrolyte glass ceramics, and also preferably includes a plurality of crushing steps. By crushing the solid electrolyte (A), the solid electrolyte (B), or the sulfide solid electrolyte glass ceramics, a sulfide solid electrolyte glass ceramics having a small particle size can be obtained while suppressing a decrease in ionic conductivity.

[0140] The mill used for the milling in this embodiment is not particularly limited as long as it can mill particles, and for example, a media mill using a milling medium can be used. As the mill, a dry mill such as a dry media mill, a dry ball mill, or a dry vibration mill, or a dry non-media mill such as a jet mill can be used. When the slurry contains a solvent, a wet bead mill, a wet ball mill, or a wet vibration mill can be exemplified. A dry bead mill or a wet bead mill using beads as a milling medium is preferred because the milling conditions can be freely adjusted and it is easy to deal with smaller particle sizes.

[0141] The size of the beads used in the grinder may be appropriately selected depending on the desired particle size, processing amount, etc. For example, the diameter of the beads may be about 0.05 mmφ or more and 5.0 mmφ or less, preferably 0.1 mmφ or more and 3.0 mmφ or less, and more preferably 0.3 mmφ or more and 1.5 mmφ or less.

[0142] The pulverizer used for pulverization in this embodiment may be a machine capable of pulverizing an object using ultrasound, such as a machine called an ultrasonic pulverizer, ultrasonic homogenizer, probe ultrasonic pulverizer, etc. In this case, various conditions such as the frequency of the ultrasound may be appropriately selected depending on the average particle size of the desired complex, and the frequency may be, for example, about 1 kHz to 100 kHz, and from the viewpoint of more efficiently pulverizing the complex, the frequency is preferably 3 kHz to 50 kHz, more preferably 5 kHz to 40 kHz, and even more preferably 10 kHz to 30 kHz.

[0143] The output of the ultrasonic crusher is usually about 500 to 16,000 W, preferably 600 to 10,000 W, more preferably 750 to 5,000 W, and even more preferably 900 to 1,500 W. The average particle size (D ５０ The average particle size is determined as desired, but is usually 0.01 μm or more and 50 μm or less, preferably 0.03 μm or more and 5 μm or less, and more preferably 0.05 μm or more and 3 μm or less. By setting the average particle size in this range, it is possible to meet the demand for a solid electrolyte having a small average particle size of 1 μm or less.

[0144] The grinding time is not particularly limited as long as it is a time that allows the complex to have a desired average particle size, and is usually from 0.1 hours to 100 hours. From the viewpoint of efficiently achieving a desired particle size, the grinding time is preferably from 0.3 hours to 72 hours, more preferably from 0.5 hours to 48 hours, and even more preferably from 1 hour to 24 hours.

[0145] (Uses of sulfide solid electrolyte glass ceramics) The sulfide solid electrolyte glass ceramics of this embodiment have a predetermined average particle size and specific surface area, as well as high ionic conductivity and excellent battery performance. ２ Since sulfur is hardly generated, the sulfide solid electrolyte glass ceramics are suitable for use in electrode composites for lithium ion batteries and lithium ion batteries. It is particularly suitable when lithium element is used as the conductive species. The sulfide solid electrolyte glass ceramics of this embodiment may be used in a positive electrode layer, a negative electrode layer, or an electrolyte layer.

[0146] The battery preferably includes a current collector in addition to the positive electrode layer, the electrolyte layer, and the negative electrode layer, and a known current collector can be used. For example, a layer of a material that reacts with the sulfide solid electrolyte glass ceramic, such as Au, Pt, Al, Ti, or Cu, coated with Au or the like can be used.

[0147] [Electrode Mixture] The electrode mixture of this embodiment is required to contain the sulfide solid electrolyte glass ceramics and an electrode active material described below.

[0148] (Electrode Active Material) As the electrode active material, a positive electrode active material or a negative electrode active material is adopted depending on whether the electrode mixture is used for a positive electrode or a negative electrode.

[0149] The positive electrode active material can be any material that can promote a battery chemical reaction involving the movement of lithium ions due to atoms that are used to exhibit ionic conductivity, preferably lithium atoms, in relation to the negative electrode active material. Examples of such positive electrode active materials that can insert and extract lithium ions include oxide-based positive electrode active materials and sulfide-based positive electrode active materials.

[0150] Oxide-based positive electrode active materials include LMO (lithium manganese oxide), LCO (lithium cobalt oxide), NMC (lithium nickel manganese cobalt oxide), NCA (lithium nickel cobalt aluminate), LNCO (lithium nickel cobalt oxide), and olivine-type compounds (LiMeNPO ４, Me=Fe, Co, Ni, Mn) and other lithium-containing transition metal composite oxides are preferred. Examples of sulfide-based positive electrode active materials include titanium sulfide (TiS ２ ), molybdenum sulfide (MoS ２ ), iron sulfide (FeS, FeS ２ ), copper sulfide (CuS), nickel sulfide (Ni ３ S ２ In addition to the positive electrode active material, niobium selenide (NbSe) ３ The positive electrode active material may be used alone or in combination of two or more.

[0151] The negative electrode active material can be any atom that exhibits ionic conductivity, preferably a metal capable of forming an alloy with lithium atoms, its oxide, or an alloy of the metal with lithium atoms, as long as it can promote a battery chemical reaction involving the migration of lithium ions due to lithium atoms. As such a negative electrode active material capable of inserting and extracting lithium ions, any material known in the battery field as a negative electrode active material can be used without limitation. Examples of such a negative electrode active material include metals that can form alloys with metallic lithium or metallic lithium, such as metallic lithium, metallic indium, metallic aluminum, metallic silicon, and metallic tin, oxides of these metals, and alloys of these metals with metallic lithium.

[0152] The electrode active material used in this embodiment may have a coating layer on its surface. Examples of materials for forming the coating layer include ion conductors such as nitrides, oxides, or composites of atoms that exhibit ionic conductivity in the sulfide solid electrolyte, preferably lithium atoms. Specifically, lithium nitride (Li ３ N), Li ４ GeO ４ The main structure is, for example, Li ４－２ｘ Zn ｘ GeO ４ Conductors having a lysicone-type crystal structure such as Li ３ P.O. ４ For example, Li ４－ｘ Ge１－ｘ P ｘ S ４ Conductors having a thiolicon-type crystal structure such as La ２／３－ｘ Li ３ｘ TiO ３ Conductors having a perovskite crystal structure such as LiTi ２ (P.O. ４ ) ３ Conductors having a NASICON type crystal structure such as Li ｙ Ti ３－ｙ O ４ (0<y<3), Li ４ Ti ５ O １２ Lithium titanate (LTO), LiNbO ３ , LiTaO ３ Lithium metal oxides of metals belonging to Group 5 of the periodic table, such as Li ２ Alumni ２ O ３ -P ２ O ５ system, Li ２ Alumni ２ O ３ -ZnO-based, Li ２ O-Al ２ O ３ -SiO ２ -P ２ O ５ -TiO ２ Examples of suitable conductors include oxide-based conductors such as those based on ZnO.

[0153] An electrode active material having a coating layer can be obtained, for example, by applying a solution containing the various atoms constituting the material forming the coating layer to the surface of the electrode active material and then baking the electrode active material after application, preferably at 200°C to 400°C. Here, the solution containing the various atoms may be, for example, a solution containing alkoxides of various metals such as lithium ethoxide, titanium isopropoxide, niobium isopropoxide, or tantalum isopropoxide. In this case, the solvent may be an alcoholic solvent such as ethanol or butanol; an aliphatic hydrocarbon solvent such as hexane, heptane, or octane; or an aromatic hydrocarbon solvent such as benzene, toluene, or xylene. The application may be performed by immersion, spray coating, or the like.

[0154] From the viewpoint of improving production efficiency and battery performance, the firing temperature is preferably 200°C or higher and 400°C or lower, more preferably 250°C or higher and 390°C or lower, and the firing time is usually about 1 minute to 10 hours, preferably 10 minutes to 4 hours.

[0155] The coverage of the coating layer is preferably 90% or more, more preferably 95% or more, and even more preferably 100% based on the surface area of ​​the electrode active material, i.e., the entire surface is preferably covered. The thickness of the coating layer is preferably 1 nm or more, more preferably 2 nm or more, and the upper limit is preferably 30 nm or less, more preferably 25 nm or less. The thickness of the coating layer can be measured by cross-sectional observation using a transmission electron microscope (TEM), and the coverage can be calculated from the thickness of the coating layer, elemental analysis value, and BET specific surface area.

[0156] (Other Components) The electrode mixture of this embodiment may contain other components, such as a conductive material and a binder, in addition to the sulfide solid electrolyte glass ceramics and electrode active material. That is, the method for producing the electrode mixture of this embodiment may use other components, such as a conductive material and a binder, in addition to the sulfide solid electrolyte glass ceramics and electrode active material. When mixing the sulfide solid electrolyte glass ceramics and the electrode active material, the other components, such as a conductive material and a binder, may be added to and mixed with the sulfide solid electrolyte glass ceramics and the electrode active material. Examples of conductive materials that can improve battery performance by improving electronic conductivity include carbon-based materials such as artificial graphite, graphite carbon fiber, resin-baked carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads, furfuryl alcohol resin-baked carbon, polyacene, pitch-based carbon fiber, vapor-grown carbon fiber, natural graphite, and non-graphitizable carbon.

[0157] The use of a binder improves the strength of the produced positive and negative electrodes. The binder is not particularly limited as long as it can impart functions such as binding property and flexibility, and examples thereof include fluorine-based polymers such as polytetrafluoroethylene and polyvinylidene fluoride, thermoplastic elastomers such as butylene rubber and styrene-butadiene rubber, acrylic resins, acrylic polyol resins, polyvinyl acetal resins, polyvinyl butyral resins, and silicone resins.

[0158] The compounding ratio (mass ratio) of the electrode active material to the sulfide solid electrolyte glass ceramics in the electrode mixture is preferably 99.5:0.5 to 40:60, more preferably 99:1 to 50:50, and even more preferably 98:2 to 60:40, in consideration of improving battery performance and production efficiency.

[0159] When a conductive material is contained, the content of the conductive material in the electrode mixture is not particularly limited, but in consideration of improving battery performance and manufacturing efficiency, it is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, with the upper limit being preferably 10% by mass or less, preferably 8% by mass or less, and even more preferably 5% by mass or less. Furthermore, when a binder is contained, the content of the binder in the electrode mixture is not particularly limited, but in consideration of improving battery performance and manufacturing efficiency, it is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, with the upper limit being preferably 20% by mass or less, preferably 15% by mass or less, and even more preferably 10% by mass or less.

[0160] [Lithium Ion Battery] The lithium ion battery of this embodiment is required to contain at least one selected from the sulfide solid electrolyte glass ceramic of this embodiment and the electrode mixture.

[0161] The lithium ion battery of this embodiment is not particularly limited in its configuration as long as it contains either the sulfide solid electrolyte glass ceramic of this embodiment or an electrode composite containing the same, and has the configuration of a commonly used lithium ion battery.

[0162] The lithium ion battery of this embodiment preferably includes, for example, a positive electrode layer, a negative electrode layer, an electrolyte layer, and a current collector. The positive electrode layer and the negative electrode layer preferably use the electrode mixture of this embodiment, and the electrolyte layer preferably uses the sulfide solid electrolyte glass ceramic of this embodiment.

[0163] The current collector may be a known material, for example, a layer of Au or the like coated with a material that reacts with the solid electrolyte, such as Au, Pt, Al, Ti, or Cu.

[0164] The present invention will now be described in detail with reference to examples, but the present invention is not limited to these examples in any way.

[0165] (1) Measurement method will be explained. (1-1) X-ray diffraction (XRD) measurement (XRD pattern) The obtained solid electrolyte was measured by XRD measurement. The powder of the solid electrolyte produced in each example was filled into a groove with a diameter of 20 mm and a depth of 0.2 mm, and leveled with glass to prepare a sample. This sample was sealed with a Kapton film for XRD and measured without exposing it to air. Measurement was carried out using a powder X-ray diffraction measurement device D2 PHASER manufactured by BRUKER Co., Ltd. under the following conditions.

[0166] Tube voltage: 30kV Tube current: 10mA X-ray wavelength: Cu-Kα ray (1.5418Å) Optical system: Concentration method

[0167] Slit configuration: Soller slit 4° (on both the incident and receiving sides), divergence slit 1 mm, Kβ filter (Ni plate 0.5%), air scatter screen 3 mm) Detector: Semiconductor detector Measurement range: 2θ = 10-60 deg Step width, scan speed: 0.05 deg, 0.05 deg / sec From the obtained XRD pattern, a peak appearing at 2θ = 20.2° and a peak appearing at 2θ = 29.3° were identified. That is, a linear baseline was set for the peak shape obtained by XRD measurement, and the difference between the intensity at each point and the baseline was calculated to create an XRD curve. For the peak appearing at 2θ = 20.2°, a linear baseline was set in the range of 19.2 to 20.7° and subtracted, and the maximum peak value in the range of 20.2 ± 0.3° from there was taken as the peak intensity. For the region enclosed by the baseline and the curve of the XRD pattern, a peak of the function described below was set at 20.2 ± 0.2°, and the area of ​​the peak obtained by curve fitting was taken as the peak area intensity. (See Figures 2 and 4.) Furthermore, for the peak appearing at 2θ = 29.3°, a linear baseline was set in the range of 27.8 to 30.6° and subtracted, and the maximum peak value in the range of 29.3 ± 0.3° from there was taken as the peak intensity. Two peaks of the function described below were set at 28.7 ± 0.2° and 29.3 ± 0.2°, and curve fitting was performed. The area of ​​the 29.3° peak was taken as the peak area intensity. (See Figures 3 and 5.) The peak intensity (P Ａ ) and peak area intensity (I Ａ ) is the peak intensity (P Ｂ ) Peak area intensity (I Ｂ ) and from these values, P Ａ / P Ｂ and I Ａ / I Ｂ was calculated.

[0168] (1-2) X-ray diffraction (XRD) measurement (crystallite diameter) The crystallite diameter (L) was determined according to the method of P. Scherrer et al. Specifically, using the results of measurements similar to (1-1), it was determined by calculation using the following formula: Crystallite diameter (L) = Kλ / (β cos θ) K: constant, 0.9 was used λ: 1.5418 Å (Cu-Kα radiation) β: calculated from β = w-B

[0169] w: half-width of the 23.6° peak obtained by measurement B: instrument constant (a standard material (silicon) was measured in the same manner as in (1-1), and B = 0.1497° was calculated from the peak at 2θ = 28.5°.)

[0170] The w (half width obtained by measurement) was calculated as follows. That is, a linear baseline was set for the peak shape obtained by XRD measurement (see FIG. 6), and the difference between the intensity at each point and the baseline was calculated to obtain an XRD curve (see FIG. 7). The XRD curve was set as an equation consisting of a Lorentz function L(x) and a Gaussian function G(x) (f(x) = (1 - α) × L(x) + α × G(x)), and the parameters A, w, and x were calculated by curve fitting. ０ and α were determined.

[0171]

[0172] (1-3) Solid ３１ P-NMR measurement equipment: ECZ400R (manufactured by JEOL Ltd.) Observation nuclei: ３１ P Observation frequency: 161.994 MHz Measurement temperature: room temperature

[0173] Pulse sequence: Single pulse 90° pulse width: 3.2 μs Waiting time after FID measurement until next pulse application: 60 s MAS (magic angle spinning) rotation speed: 11 kHz Number of accumulations: 64 times

[0174] Measurement range: 250 ppm to -150 ppm Sample amount: 100 mg External standard: NH ４ H ２ P.O. ４ (chemical shift 1.00 ppm)

[0175] (1-3-1) Amorphous sulfide solid electrolyte ３１ Peak signals derived from each phosphorus-containing structure were extracted from the P-NMR spectrum by waveform separation using the nonlinear least squares method. The ratio of phosphorus contained in each phosphorus-containing structure to the total phosphorus (phosphorus ratio, mol%) was measured. Waveform separation was performed using the chemical shifts of each phosphorus-containing structure as shown in Table 1. The areas in the table (Sp1, Sp2, etc.) indicate the areas of the waveform-separated peaks.

[0176]

[0177] P.S. ４ ３－ Phosphorus ratio (%): 100 × Sp1 / (Sp1 + Sp2 + Sp3) P ２ S ６ ４－ Phosphorus ratio (%): 100 × Sp2 / (Sp1 + Sp2 + Sp3) P ２ S ７ ４－ Phosphorus ratio (%): 100 × Sp3 / (Sp1 + Sp2 + Sp3)

[0178] (1-3-2) In the case of crystalline solid electrolyte (A) The phosphorus ratio was determined by a method similar to (1-3-1) except that Table 2 was used as the chemical shift of each phosphorus-containing structure.

[0179]

[0180] In addition, P ２ S ７ ４－ The phosphorus ratio is P ２ S ７ ４－ Glass phosphorus ratio and P ２ S ７ ４－ It is defined as the sum of the ratio of crystalline phosphorus. ４ ３－ When the crystalline peaks could not be fully optimized with one pseudo-Voigt function, they were separated using two pseudo-Voigt functions.

[0181] (1-3-3) In the Case of the Sulfide Solid Electrolyte Glass Ceramics of the Present Invention The phosphorus ratio was determined by a method similar to (1-3-1) except that Table 3 was used as the chemical shift of each phosphorus-containing structure.

[0182]

[0183] (1-4) Ion Conductivity Measurement In this example, the ion conductivity was measured as follows. A 10 mm diameter (cross-sectional area S: 0.785 cm) sample was taken from the sulfide solid electrolyte. ２ ) and a height (L) of 0.1 to 0.3 cm, and circular pellets were molded to prepare samples. Electrode terminals were attached to the top and bottom of the sample, and measurements were made at 25°C using an AC impedance method (frequency range: 1 MHz to 100 Hz, amplitude: 10 mV) to obtain a Cole-Cole plot. The real part Z' (Ω) at the point where -Z'' (Ω) is minimum near the right end of the arc observed in the high-frequency region was defined as the bulk resistance R (Ω) of the electrolyte, and the ionic conductivity σ (S / cm) was calculated according to the following formula:

[0184] R=ρ(L / S) σ=1 / ρ

[0185] (1-5) Water resistance evaluation (H ２ The exposure test apparatus (see Figure 8) mainly comprises a flask 10 for humidifying nitrogen, a static mixer 20 for mixing humidified and non-humidified nitrogen, a dew-point meter 30 (M170 / DMT152 manufactured by VAISALA) for measuring the moisture content of the mixed nitrogen, a double-walled reaction tube 40 in which a measurement sample is placed, a dew-point meter 50 for measuring the moisture content of the nitrogen discharged from the double-walled reaction tube 40, and a hydrogen sulfide meter 60 (Model 3000RS manufactured by AMI) for measuring the hydrogen sulfide concentration in the discharged nitrogen, all of which are connected by piping (not shown). The temperature of the flask 10 was set to 10°C by a cooling bath 11. Note that 6 mm diameter Teflon (registered trademark) tubing was used to connect the various components. The tubing is omitted in Figure 8, and instead, the flow of nitrogen is indicated by arrows.

[0186] The evaluation procedure was as follows: In a nitrogen glove box with a dew point of −80° C., about 0.15 g of powder sample 41 was weighed out, and placed inside reaction tube 40 so as to be sandwiched between quartz wool 42 and then sealed.

[0187] Nitrogen was supplied into the apparatus 1 at 0.02 MPa from a nitrogen source (not shown). The supplied nitrogen passed through a bifurcated branch pipe BP, with a portion being supplied to the flask 10 and humidified. The remainder was supplied directly to the static mixer 20 as unhumidified nitrogen. The amount of nitrogen supplied to the flask 10 was adjusted by a needle valve V. The dew point was controlled by adjusting the flow rates of the unhumidified nitrogen and humidified nitrogen with a needle valve-equipped flow meter FM. Specifically, unhumidified nitrogen was supplied to the static mixer 20 at a flow rate of 800 mL / min and humidified nitrogen at a flow rate of 10 to 30 mL / min, and the gas mixture (a mixture of unhumidified nitrogen and humidified nitrogen) was mixed, and the dew point of the mixed gas (a mixture of unhumidified nitrogen and humidified nitrogen) was confirmed using a dew point meter 30.

[0188] After adjusting the dew point to -20°C, the three-way cock 43 was rotated to allow the mixed gas to flow through the reaction tube 40 for 2 hours. The amount of hydrogen sulfide contained in the mixed gas that had passed through the sample 41 was measured with a hydrogen sulfide measuring instrument 60. The amount of hydrogen sulfide generated during this period was calculated per 1 g of sample (unit: cc / g). After measurement, the gas was passed through an alkali trap 70 to remove hydrogen sulfide. After the sample had been exposed for a predetermined time, the supply of humidified nitrogen was stopped, and the reaction tube 40 was sealed with unhumidified nitrogen.

[0189] (1-6) Determination of composition using an inductively coupled plasma (ICP) optical emission spectrometer. The sulfide solid electrolyte powder was weighed and collected in a vial in an argon atmosphere. An alkaline KOH solution was placed in the vial, and the sample was dissolved therein while taking care not to collect sulfur content. The solution was then diluted appropriately to obtain a measurement solution. The resulting measurement solution was measured using a Paschen-Runge type ICP-OES device (SPECTRO ARCOS, manufactured by SPECTRO) to determine the composition.

[0190] The calibration curve solutions were prepared using 1000 mg / L standard solutions for ICP measurement for Li, P, and S, 1000 mg / L standard solution for ion chromatography for Br, and potassium iodide (special grade reagent) for I. Two measurement solutions were prepared for each sulfide solid electrolyte, and measurements were performed four times for each measurement solution, and the average value was calculated. The composition was determined from the average of the measured values ​​of the two measurement solutions. From the obtained element ratios, Li ２Molar fraction of S (ILi ２ S) and P ２ S ５ Mole fraction of (I2P ２ S ５ ) ratio (I2Li ２ S / I2P ２ S ５ ) was calculated.

[0191] (2) Lithium sulfide (Li ２ S) and diphosphorus pentasulfide (P ２ S ５ Preparation example of (2-1) Lithium sulfide (Li ２ Example of preparation of S)

[0192] (2-1-1) Li ２ Preparation of S Toluene (manufactured by Sumitomo Corporation) was used as a non-aqueous medium and 303.8 kg of the dehydrated toluene was added to a 500 L (liter) stainless steel reaction kettle under a nitrogen stream. Subsequently, 33.8 kg of anhydrous lithium hydroxide (manufactured by Honjo Chemical Co., Ltd.) was added, and the mixture was stirred at 131 rpm using a Twin Star stirring blade at 95°C for 2 hours to form a slurry.

[0193] While continuing stirring, hydrogen sulfide (manufactured by Sumitomo Seika Chemicals Co., Ltd.) was blown into the slurry at a feed rate of 100 L / min, and the temperature was raised to 104°C. Azeotropic gas of water and toluene was continuously discharged from the reaction vessel. This azeotropic gas was dehydrated by condensing it in a condenser outside the system. During this time, toluene in an amount equal to the toluene distilled was continuously supplied to maintain the reaction liquid level constant. The amount of water in the condensate gradually decreased, and distillation of water was no longer observed 24 hours after the introduction of hydrogen sulfide. During the reaction, solids were dispersed in the toluene and stirred, and no water separated from the toluene.

[0194] After this, hydrogen sulfide was replaced with nitrogen and the nitrogen was passed through at 100 L / min for 1 hour. The solid matter obtained was filtered and dried to obtain Li, which was a white powder. ２ S was obtained. ２ S's D ５０ was 412 μm.

[0195] (2-1-2) Li ２ Pulverization of S (2-1-1) ２ LiS was pulverized in a nitrogen atmosphere using a pin mill (100UPZ manufactured by Hosokawa Micron Corporation) equipped with a constant feeder. The feeding rate was 80 g / min, and the rotation speed of the disk was 18,000 rpm. ２ S's D ５０ was 7.7 μm.

[0196] (2-2) Diphosphorus pentasulfide (P ２ S ５ ) Preparation example (2-2-1) P ２ S ５ In (2-1-2), the Li obtained in (2-1-1) ２ Replace S with P ２ S ５ (Thermophos, D ５０ The powder was crushed in the same manner except that the powder was crushed using a powder of 125 μm. ２ S ５ D ５０ was 8.7 μm.

[0197] (Example 1) Step (A) Li produced in (2-1-2) ２ S 0.488g (45.947g / mol, 0.01062mol), P produced in (2-2-1) ２ S ５ 1.012 g (222.272 g / mol, 0.00455 mol) of the above and ten 10 mm diameter zirconia balls (approximately 32 g) were placed in a zirconia pot (45 mL) using a planetary ball mill (manufactured by Fritsch: model number P-7), completely sealed, and the pot was filled with an argon atmosphere. Without heating or cooling, the planetary ball mill was operated at a rotation speed of 370 rpm and treated (mechanical milling) for 40 hours to obtain a powder (solid electrolyte (A1)). The obtained powder (solid electrolyte (A1)) was confirmed to be an amorphous solid electrolyte by X-ray diffraction (XRD) measurement (see FIG. 9).

[0198] Heating (crystallization) step (first time): The entire amount of the solid electrolyte (A1) obtained in step (A) was heated in an electric furnace at 300°C for 3 hours in a glove box under an argon atmosphere. The solid electrolyte was then slowly cooled and pulverized in a mortar in a glove box under an argon atmosphere to obtain a powder (crystalline solid electrolyte (A2)). The results of X-ray diffraction (XRD) measurement are shown in Figure 10.

[0199] Step (B) 1.001 g of the solid electrolyte (A2) obtained in step (A) was weighed out and added with Li ２ An amorphous solid electrolyte (B1) was obtained in the same manner as in step (A) except that 0.093 g (0.00202 mol) of S and 0.406 g (133.845 g / mol, 0.00304 mol) of LiI as a lithium halide were added. The results of X-ray diffraction (XRD) measurement of the amorphous solid electrolyte (B1) are shown in FIG. 11. ３１ P-NMR measurement ２ S ６ ４－ The phosphorus ratio was evaluated (see Table 5).

[0200] Heating (crystallization) step: The entire amount of the amorphous solid electrolyte (B1) obtained in step (B) was heated on a hot plate at 180°C for 2 hours in a glove box under an argon atmosphere, then slowly cooled, and pulverized in a mortar in a glove box under an argon atmosphere to obtain a powder (sulfide solid electrolyte glass ceramics (1)).

[0201] The obtained powder was subjected to X-ray diffraction (XRD) measurement (see FIG. 12), and peaks at 2θ = 20.2°, 23.6°, and 29.3° were observed, which were derived from a crystalline structure similar to that of thiolicon region II. ２ It was confirmed that the raw materials S and LiI were consumed, and it was found that a sulfide solid electrolyte glass ceramic containing less of these raw materials as impurities was obtained.

[0202] (Comparative Example 1) Li produced in (2-1-2) ２ S was 0.451 g (0.00981 mol), P produced in (2-2-1) ２ S ５An amorphous solid electrolyte (C1) was obtained in the same manner as in the step (B) of Example 1, except that 0.727 g (0.00327 mol) of the above, 0.109 g (0.00082 mol) of LiI as a lithium halide, and 0.213 g (86.845 g / mol, 0.00245 mol) of LiBr were added.

[0203] Crystallization Step: The entire amount of the obtained amorphous sulfide solid electrolyte (C1) was heated on a hot plate at 190°C for 2 hours in a glove box under an argon atmosphere. It was then slowly cooled and pulverized in a mortar in a glove box under an argon atmosphere to obtain a powder (sulfide solid electrolyte glass ceramics (C1)). X-ray diffraction (XRD) measurement of the obtained powder (see Figure 13) showed peaks derived from a crystalline structure similar to thiolicon region II, confirming that it was a sulfide solid electrolyte glass ceramic.

[0204] Comparative Example 2: 1.070 g of the solid electrolyte (A2) obtained by heating the solid electrolyte (A1) obtained in step (A) was weighed out, and Li was added to the solid electrolyte (A2). ２ An amorphous solid electrolyte (C2)2 was obtained in the same manner as in step (B) of Example 1, except that 0.100 g (0.00218 mol) of S, 0.109 g (0.00082 mol) of LiI as a lithium halide, and 0.213 g (86.845 g / mol, 0.00245 mol) of LiBr were added. The entire amount of the obtained amorphous sulfide solid electrolyte (C2) was heated on a hot plate at 180 ° C. for 2 hours in a glove box with an argon atmosphere to obtain a sulfide solid electrolyte glass ceramic (C2). X-ray diffraction (XRD) measurement was performed on the obtained powder, and peaks derived from a crystalline structure similar to thiolicon region II were observed.

[0205] (Comparative Example 3) Li produced in (2-1-2) ２ S 0.440 g (0.00958 mol), P produced in (2-2-1) ２ S ５0.709 g (0.00319 mol), 0.213 g (0.00159 mol) of LiI as lithium halide, 0.138 g (0.00159 mol) of LiBr, and 53 g of zirconia balls having a diameter of 2 mm, and the solvent ethylbenzene (5 mL) were placed in a planetary ball mill (manufactured by Fritsch: model number P-7) zirconia pot (45 mL), completely sealed, and the inside of the pot was filled with an argon atmosphere. Without heating or cooling, the rotation speed was set to 500 rpm in the planetary ball mill, and the treatment (mechanical milling) was carried out for 40 hours. The obtained slurry was dried at room temperature under vacuum and then heated to 80 ° C. to obtain a powder (amorphous solid electrolyte (C3)). The obtained powder was confirmed to be an amorphous solid electrolyte by X-ray diffraction (XRD) measurement.

[0206] Crystallization Step: The entire amount of the obtained amorphous sulfide solid electrolyte (C3) was heated on a hot plate at 203°C for 2 hours in a glove box under an argon atmosphere. It was then slowly cooled and pulverized in a mortar in a glove box under an argon atmosphere to obtain a powder (sulfide solid electrolyte glass ceramics (C3)). X-ray diffraction (XRD) measurement was performed on the obtained powder, and peaks derived from a crystalline structure similar to thiolicon region II were observed.

[0207] (Examples 2 to 10) The solid electrolyte (A2) used in step (B) of Example 1, Li ２ Sulfide solid electrolyte glass ceramics (2) to (10) were obtained in the same manner as in Example 1, except that S, LiI, LiBr and their amounts, and the heating temperature in the crystallization step were set as shown in Table 4. In Table 4, electrolyte A2 means the amount (g) of the crystalline solid electrolyte (A2) used in step (B). In Comparative Examples 1 and 3, the crystalline solid electrolyte (A2) was not used, and Li ２ S, P ２ S ５ Since lithium halide and electrolyte A2 were treated together, the amount of electrolyte A2 used is shown as "-". ２ S ５ is the P used at that time ２ S ５ In Examples 1 to 10 and Comparative Example 2, P ２ S５ As with the sulfide solid electrolyte glass ceramics (1), peaks at 2θ = 20.2°, 23.6°, and 29.3° were observed at these temperatures, which are attributable to a crystalline structure similar to thiolicon region II.

[0208]

[0209] Table 4 shows the sulfur atom, phosphorus atom, and halogen atom contents (mol) per lithium atom content (mol) calculated from the content of each element in the raw materials of the sulfide solid electrolyte ceramics obtained in Examples 1 to 10 and Comparative Examples 1 to 3.

[0210] Also, P Ａ / P Ｂ , I Ａ / I Ｂ , M Ｂｒ / M Ｉ , P ２ S ６ ４－ Phosphorus ratio and I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ Table 5 shows the crystallite size, ionic conductivity and H ２ The amount of sulfur generated is shown in Table 6. The blank spaces in Tables 5 and 6 indicate that no measurement was performed.

[0211]

[0212]

[0213] The sulfide solid electrolyte glass ceramics of Examples 1 to 10 were found to have high ionic conductivity and to be suitable as materials for lithium ion batteries, etc. In addition, the ratio ILi calculated from the content of each element in the raw materials ２ S / I1P ２ S ５ and the ratio ILi measured using an inductively coupled plasma (ICP) optical emission spectrometer. ２ S / I2P ２ S ５In Examples 1 and 8, the composition deviations were 9.1% and 5.6%, respectively, but in the other Examples, the deviations were about 2%, and it was confirmed that the ratios were generally consistent with those in the raw materials. ２ S) and phosphorus sulfide (P ２ S ５ It has been confirmed that a sulfide solid electrolyte glass ceramic having high ionic conductivity can be obtained by effectively utilizing the solid electrolytes (A) and (B) obtained from raw materials containing these.

[0214] The sulfide solid electrolyte glass ceramics (C1) of Comparative Example 1 was produced by a production method that does not include step (A), which is different from the production method of the sulfide solid electrolyte glass ceramics of the present embodiment. Ａ / P Ｂ The sulfide solid electrolyte glass ceramics (C1) had a lower ionic conductivity than the sulfide solid electrolyte glass ceramics of the examples, and the P Ａ / P Ｂ It was found that if the value is 1.0 or less, the effect of the present invention is not exhibited.

[0215] The sulfide solid electrolyte glass ceramics (C2) of Comparative Example 2 was prepared by changing the amounts of LiI and LiBr used. Ａ / P Ｂ The sulfide solid electrolyte glass ceramics (C2) had a lower ionic conductivity than the sulfide solid electrolyte glass ceramics of the examples. Ａ / P Ｂ It was found that since the value of the crystallite diameter is 1.0 or less, the crystallite diameter does not become large.

[0216] The sulfide solid electrolyte glass ceramics (C3) of Comparative Example 3 was prepared by adjusting the amounts of LiI and LiBr used. Ａ / P Ｂ is 1.0, and P Ａ / P ＢThe sulfide solid electrolyte glass ceramics of Comparative Example 3 (C3) had a low ionic conductivity because the P ２ S ６ ４－ High phosphorus ratio, H ２ The amount of S generated was inferior.

[0217] Furthermore, the sulfide solid electrolyte glass ceramics of Examples 1 to 10 have smaller H ２ It was confirmed that the generation of S was suppressed.

[0218] According to this embodiment, a crystalline sulfide solid electrolyte having high ionic conductivity and excellent battery performance can be produced. The crystalline sulfide solid electrolyte obtained by the production method of this embodiment is suitable for use in lithium ion batteries, particularly batteries used in information-related devices and communication devices such as personal computers, video cameras, and mobile phones.

Claims

1. It contains lithium atoms, sulfur atoms, phosphorus atoms and halogen atoms, In X-ray diffraction measurements using CuKα rays, the diffraction angles (2θ) have peaks at 20.2° and 29.3°, and the peak intensity (P) of the peak appearing at 2θ = 20.2° is Ａ ) and the peak intensity of the peak appearing at 2θ = 29.3° (P Ｂ The intensity ratio value (P Ａ / P Ｂ A sulfide solid electrolyte glass ceramic having a coefficient greater than 1.0 and a crystallite size of 30 nm or more.

2. The peak area intensity of the peak appearing at 2θ = 20.2° (I Ａ ) and the peak area intensity of the peak appearing at 2θ = 29.3° (I Ｂ The value of the intensity ratio (I Ａ / I Ｂ The sulfide solid electrolyte glass ceramic according to claim 1, wherein the ratio is 0.78 or higher.

3. Furthermore, the sulfide solid electrolyte glass ceramic according to claim 1 or 2, having a peak at 2θ = 23.6°.

4. The sulfide solid electrolyte glass ceramic according to claim 1 or 2, wherein the halogen atom comprises an iodine atom.

5. The sulfide solid electrolyte glass ceramic according to claim 4, further comprising a bromine atom as the halogen atom.

6. The content (mol) of bromine atoms contained in the sulfide solid electrolyte glass ceramics is M Ｂｒ mol), and the content (mol) of iodine atoms is M Ｉ mol), satisfying the relationship of M Ｂｒ / M Ｉ ≤ 1.

00. The sulfide solid electrolyte glass ceramics according to claim 5

7. solid ３１ P obtained from P-NMR measurement ２ S ６ ４－ The sulfide solid electrolyte glass ceramic according to claim 1 or 2, wherein the phosphorus ratio is 7.5 mol% or less.

8. Li is calculated from the content of each element in the raw materials. ２ Mole fraction of S (I1 Ｌｉ２Ｓ ) and P ２ S ５ mole fraction (I1 Ｐ２Ｓ５ ) ratio (I1 Ｌｉ２Ｓ / I1 Ｐ２Ｓ５ The sulfide solid electrolyte glass ceramic according to claim 1 or 2, wherein the ratio is 2.60 or more and 3.30 or less.

9. Li measured using an inductively coupled plasma (ICP) emission spectrometer. ２ Mole fraction of S (I² Ｌｉ２Ｓ ) and P ２ S ５ The mole fraction (I2 Ｐ２Ｓ５ ) ratio (I2 Ｌｉ２Ｓ / I2 Ｐ２Ｓ５ The sulfide solid electrolyte glass ceramic according to claim 1 or 2, wherein the ratio is 2.60 or more and 3.30 or less.

10. The sulfide solid electrolyte glass ceramic according to claim 1 or 2, wherein the ratio (content ratio) of lithium atom content (mol), phosphorus atom content (mol), sulfur atom content (mol), and halogen atom content (mol) is lithium atom:phosphorus atom:sulfur atom:halogen atom = (3.20 to 3.70): (0.70 to 1.30): (3.00 to 5.00): (0.20 to 0.70).

11. A sulfide solid electrolyte glass ceramic according to claim 1 or 2, comprising a thiolysicon region type II crystal structure.

12. Lithium sulfide (Li ２ S) and phosphorus sulfide (P ２ S ５ The solid electrolyte (A) is obtained by treating it with at least one selected from stirring, mixing, and grinding. The solid electrolyte (A) and lithium halide are treated by at least one selected from stirring, mixing, and grinding to obtain a solid electrolyte (B). A method for producing sulfide solid electrolyte glass ceramics according to claim 1, comprising:

13. A method for producing sulfide solid electrolyte glass ceramics according to claim 12, further comprising heating the solid electrolyte (A).

14. A method for producing sulfide solid electrolyte glass ceramics according to claim 12 or 13, further comprising heating the solid electrolyte (B).

15. The solid electrolyte (B) ３１ P obtained from P-NMR measurement ２ S ６ ４－ A method for producing sulfide solid electrolyte glass ceramics according to claim 12 or 13, wherein the phosphorus ratio is 15.0 mol% or less.

16. An electrode composite comprising the sulfide solid electrolyte glass ceramics described in claim 1 and an electrode active material.

17. A lithium-ion battery comprising at least one of the sulfide solid electrolyte glass ceramics described in claim 1 and the electrode composite material described in claim 16.