Active material, solid electrolyte, electrode mixture, and battery

Abstract

The purpose of the present invention is to provide an active material and a solid electrolyte capable of improving the performance of a lithium-sulfur battery. An active material according to the present invention contains: a compound containing a lithium (Li) element, a sulfur (S) element, a phosphorus (P) element, an iron (Fe) element, and a halogen (X) element; and a conductive material which has a diffraction peak caused by lithium sulfide when measured by an X-ray diffraction device using CuK [alpha] 1 rays, and wherein the molar ratios of the elements in the compound satisfy the following relational expressions (1)-(4). (1) 5.8 < = Li / (Fe + P) < = 10.0 (2) 0.1 < = X / (Fe + P) < = 1.4 (3) 0.2 < = X + Fe < = 2.0 (4) 0.0 < Fe / (Fe + P) < 1.0.

Description

Technical Field

[0001] The present invention relates to an active material and a solid electrolyte, an electrode mixture containing the active material, and a battery containing the active material and the solid electrolyte. Background Art

[0002] The applicant previously proposed a method for producing an active material by mixing a sulfide containing elements such as lithium, sulfur, and phosphorus and having a crystalline phase with an argyrodite-type crystal structure with a conductive material and forming a composite of the two (see Patent Document 1). The active material produced using this method can improve the performance of lithium-ion batteries to levels equal to or higher than those previously achieved. Furthermore, this active material does not require rare metals such as cobalt, making it economically advantageous.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2022 / 045302 Pamphlet Summary of the Invention

[0006] Problems to be solved by the invention

[0007] The present inventors have conducted research with the goal of improving the performance of lithium-ion batteries and have discovered the need to develop active materials and solid electrolytes that can further improve the performance of lithium-ion batteries.

[0008] An object of the present invention is to provide an active material and a solid electrolyte that can improve the performance of a lithium ion battery.

[0009] The present inventors have discovered that by controlling the amount of a specific element, specifically iron (Fe), added to the sulfide used as the active material proposed in Patent Document 1, and compounding the resulting sulfide with a conductive material to form an active material, or by using the sulfide as a solid electrolyte, battery performance such as capacity and rate characteristics can be further improved compared to conventional methods.

[0010] The present invention is made based on the above findings and provides an active material comprising a compound and a conductive material.

[0011] The aforementioned compound contains lithium (Li) element, sulfur (S) element, phosphorus (P) element, iron (Fe) element and halogen (X) element,

[0012] In the X-ray diffraction pattern measured by an X-ray diffraction apparatus using CuKα1 rays, there are peaks at positions of 2θ=27.1°±0.5° and 31.4°±0.5°.

[0013] The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship equations (1) to (4).

[0014] (1)5.8≤Li / (Fe+P)≤10.0

[0015] (2)0.1≤X / (Fe+P)≤1.4

[0016] (3)0.2≤X+Fe≤2.0

[0017] (4) 0.0<Fe / (Fe+P)<1.0

[0018] The present invention also provides a solid electrolyte comprising a compound containing lithium (Li), sulfur (S), phosphorus (P), iron (Fe) and halogen (X).

[0019] The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship.

[0020] (1)5.8≤Li / (Fe+P)≤10.0

[0021] (2)0.1≤X / (Fe+P)≤1.4

[0022] (3)0.2≤X+Fe≤2.0

[0023] (4) 0.0<Fe / (Fe+P)<1.0 BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 These are the X-ray diffraction patterns of the active material and solid electrolyte produced in Example 1.

[0025] Figure 2 These are the X-ray diffraction patterns of the active material and solid electrolyte produced in Example 2.

[0026] Figure 3 These are the X-ray diffraction patterns of the active material and solid electrolyte produced in Example 3.

[0027] Figure 4 These are the X-ray diffraction patterns of the active material and solid electrolyte produced in Example 4.

[0028] Figure 5 These are the X-ray diffraction patterns of the active material and solid electrolyte produced in Example 5.

[0029] Figure 6 This is the X-ray diffraction pattern of the active material and solid electrolyte produced in Comparative Example 1.

[0030] Figure 7 This is the X-ray diffraction pattern of the active material and solid electrolyte produced in Comparative Example 2.

[0031] Figure 8 This is the X-ray diffraction pattern of the active material and solid electrolyte produced in Comparative Example 3.

[0032] Figure 9 This is the X-ray diffraction pattern of the active material and solid electrolyte produced in Comparative Example 4.

[0033] Figure 10 This is the X-ray diffraction pattern of the active material and solid electrolyte produced in Comparative Example 5.

[0034] Figure 11 This is a charge and discharge curve of a battery using the active material produced in Example 1 as a positive electrode active material.

[0035] Figure 12 This is a charge and discharge curve of a battery using the active material produced in Example 5 as a positive electrode active material.

[0036] Figure 13 This is a charge and discharge curve of a battery using the active material produced in Comparative Example 2 as a positive electrode active material.

[0037] Figure 14 This is a charge and discharge curve of a battery using the active material produced in Comparative Example 4 as a positive electrode active material. DETAILED DESCRIPTION

[0038] The present invention will be described below based on preferred embodiments. The active material of the present invention comprises particles of a specific compound and particles of a conductive material. The active material of the present invention preferably comprises particles of a specific compound and particles of a conductive material dispersed on the surface and / or within the particles of the compound and imparting electronic conductivity to the compound. Batteries equipped with the active material of the present invention having such a structure have a high initial discharge capacity and maintain a high capacity even when discharged at high rates.

[0039] To further enhance the aforementioned advantages, the compound and the conductive material are preferably complexed. Examples of "complexation" include: a method in which conductive material particles are inseparably dispersed on the surface and / or within particles of the compound; and a method in which the compound particles and conductive material particles chemically react and bond. In particular, the compound and conductive material are preferably complexed in such a way that they are inseparably bound.

[0040] "Inseparably dispersed" refers to a state where, for example, when observing the active material of the present invention using a scanning electron microscope equipped with an energy dispersive X-ray spectrometer (SEM-EDS) and mapping the constituent elements of the compound (e.g., sulfur) and the constituent elements of the conductive material, the constituent elements of the compound (e.g., sulfur) and the constituent elements of the conductive material are confirmed to exist in an overlapping manner. Alternatively, when observing a cross-section of an electrode of a battery fabricated using the active material of the present invention, the constituent elements of the compound (e.g., sulfur) and the constituent elements of the conductive material are confirmed to exist in an overlapping manner on the surface or within the active material.

[0041] When the conductive material is a carbon material, the composite of the compound and the conductive material can be confirmed based on the presence or absence of a C—S bond using, for example, Raman spectroscopy or photoelectron spectroscopy.

[0042] The active material of the present invention can smoothly supply and demand electrons between the active material and the aforementioned compound with the aid of a conductive material, thereby obtaining the desorption and storage function of lithium ions while obtaining conductivity. In particular, as described later, when the aforementioned compound has a specific composition, the initial discharge capacity of the battery having the active material of the present invention is increased, and high capacity can be maintained even when discharged at a high rate. From this point of view, the active material of the present invention is useful as a positive electrode active material for lithium ion batteries. In contrast, previously known sulfur-based positive electrode active materials such as elemental sulfur, lithium sulfide (Li2S) and its composite materials, or metal sulfides do not show conductivity or lack conductivity. Therefore, even if these materials are used as active materials, the desired battery performance cannot be obtained.

[0043] The compound comprises lithium (Li), sulfur (S), phosphorus (P), iron (Fe), and halogen (X). Hereinafter, for convenience, the compound is also referred to as an "iron-containing compound."

[0044] The element X is at least one element selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Among these halogen elements, at least one of Cl and Br is preferably used from the viewpoint of increasing the initial discharge capacity of a battery containing the active material of the present invention and maintaining a high capacity even when the battery is discharged at a high rate.

[0045] The constituent elements of the iron-containing compound satisfy a specific relationship. Specifically, in the iron-containing compound, the molar ratio of lithium (Li) to the sum of iron (Fe) and phosphorus (P) satisfies the following relationship (1).

[0046] 5.8≤Li / (Fe+P)≤10.0 (1)

[0047] By satisfying equation (1) with the iron-containing compound, the battery containing the active material of the present invention has an increased initial discharge capacity and can maintain a high capacity even during high-rate discharge. From this perspective, equation (1) preferably satisfies the following equation (1'), and more preferably, (1").

[0048] 6.3≤Li / (Fe+P)≤9.0 (1')

[0049] 7.8≤Li / (Fe+P)≤8.5 (1”)

[0050] In the iron-containing compound, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element as constituent elements satisfies the following relational expression (2).

[0051] 0.1≤X / (Fe+P)≤1.4 (2)

[0052] By satisfying equation (2) with the iron-containing compound, the battery containing the active material of the present invention has an increased initial discharge capacity and can maintain a high capacity even during high-rate discharge. From this perspective, equation (2) preferably satisfies the following equation (2'), and more preferably, (2").

[0053] 0.2≤X / (Fe+P)≤1.0 (2')

[0054] 0.2≤X / (Fe+P)≤0.8 (2”)

[0055] Furthermore, the constituent elements of the iron-containing compound satisfy the following relational expression (3).

[0056] 0.2≤X+Fe≤2.0 (3)

[0057] When the sum of the molar numbers of the halogen (X) element and the iron (Fe) element as constituent elements of the iron-containing compound satisfies equation (3), the initial discharge capacity of a battery containing the active material of the present invention is increased, and a high capacity can be maintained even during high-rate discharge. From this perspective, equation (3) preferably satisfies the following equation (3'), and more preferably, (3").

[0058] 0.4≤X+Fe≤1.5 (3')

[0059] 0.6≤X+Fe≤1.0 (3”)

[0060] Furthermore, in the iron-containing compound, the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element as constituent elements satisfies the following relational expression (4).

[0061] 0.0<Fe / (Fe+P)<1.0 (4)

[0062] By satisfying equation (4) above, the iron-containing compound increases the initial discharge capacity of a battery containing the active material of the present invention and maintains a high capacity even during high-rate discharge. From this perspective, equation (4) preferably satisfies the following equation (4'), and more preferably satisfies (4").

[0063] 0.1<Fe / (Fe+P)<0.8 (4')

[0064] 0.2<Fe / (Fe+P)<0.6 (4”)

[0065] As the iron-containing compound satisfying the above-mentioned relationship, it is particularly preferable to use a compound represented by the following composition formula (A) from the viewpoint of further improving the characteristics as an active material.

[0066] Li a Fe d P e M 1-d-e S b X c (A)

[0067] In the formula, M is at least one element selected from the group consisting of germanium (Ge), antimony (Sb), silicon (Si), tin (Sn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co), and manganese (Mn).

[0068] From the viewpoint of further improving the initial discharge capacity of the battery and maintaining a high capacity even when discharged at a high rate, a in composition formula (A) is preferably 5.8 or more and 10.0 or less, more preferably 6.5 or more and 9.5 or less, and even more preferably 7.0 or more and 9.0 or less.

[0069] From the same viewpoint, b in composition formula (A) is preferably 3.5 or more and 6.0 or less, more preferably 4.5 or more and 5.9 or less, and even more preferably 5.0 or more and 5.8 or less.

[0070] From the same viewpoint, c in composition formula (A) is preferably 0.1 or more and 1.4 or less, more preferably 0.2 or more and 1.0 or less, and even more preferably 0.4 or more and 0.8 or less.

[0071] Furthermore, from the same viewpoint, e in composition formula (A) is preferably greater than 0 and less than 1, more preferably 0.7 to 0.9, and even more preferably 0.6 to 0.9, under the condition that d + e is 1 or less, particularly d + e is 1. d in composition formula (A) is preferably 1-e.

[0072] In particular, from the viewpoint of maintaining a higher capacity even when discharged at a high rate, M in the composition formula (A) is preferably at least one of Ge, Sb, Sn, and Si.

[0073] Among the iron-containing compounds represented by the above-mentioned composition formula (A), the use of the compound represented by the following composition formula (B) is preferred because it provides an active material capable of maintaining a higher capacity even during high-rate discharge.

[0074] Li 7-y+3x Fe x P 1-x S 6-y X y (B)

[0075] In the formula, x is preferably a number greater than 0 and less than 1, more preferably 0.1 to 0.8, further preferably 0.1 to 0.6, and even more preferably 0.2 to 0.6.

[0076] y is preferably 0 or more and 1.4 or less, more preferably 0.2 or more and 1.2 or less, further preferably 0.2 or more and 1.0 or less, and even more preferably 0.2 or more and 0.8 or less.

[0077] The composition of each element contained in the iron-containing compound can be measured by, for example, ICP emission spectrometry.

[0078] Patent Document 1, International Publication No. 2022 / 045302, previously described in the Background Art section, describes an active material obtained by mixing a sulfide containing elements such as Li, S, and P and having a crystalline phase with an argyrodite-type crystal structure with a conductive material and forming a composite of the two. In this active material, sufficient contact between the conductive material and the entire sulfide is difficult, and there is a risk that a conductive path composed of the conductive material will not be fully formed throughout the sulfide. In contrast, the present inventors believe that the iron-containing compound used in the present invention contains Fe, which imparts conductivity to the entire iron-containing compound. Therefore, the composite with the conductive material allows for sufficient conductivity. As a result, batteries containing the active material of the present invention have a high initial discharge capacity and maintain a high capacity even during high-rate discharge.

[0079] The iron-containing compound preferably contains, in addition to the aforementioned elements, a crystal phase having an argyrodite-type crystal structure. This further enhances the properties of the active material of the present invention. Whether the active material of the present invention contains a crystal phase having an argyrodite-type crystal structure can be determined by analyzing the active material of the present invention using X-ray diffraction. For example, CuKα radiation can be used.

[0080] The iron-containing compound preferably has diffraction peaks at 2θ=25.19°±1.00° and 29.62°±1.00° in an X-ray diffraction pattern measured using CuKα1 radiation. These peaks are derived from an argyrodite-type crystal phase.

[0081] In the X-ray diffraction pattern of the above-mentioned iron-containing compound measured using CuKα1 radiation, it is preferred that in addition to positions at 2θ=25.19°±1.00° and 29.62°±1.00°, further selected from the group consisting of 2θ=15.34°±1.00°, 17.74°±1.00°, 30.97°±1.00°, 44.37°±1.00°, 47.22°±1.00° and 51.70°±1.00°, the X-ray diffraction pattern of the above-mentioned iron-containing compound measured using CuKα1 radiation is The diffraction peaks preferably exist at one or more positions within 2θ = 0°; more preferably, in addition to the positions of 2θ = 25.19° ± 1.00° and 29.62° ± 1.00°, they also preferably exist at all positions of 2θ = 15.34° ± 1.00°, 17.74° ± 1.00°, 30.97° ± 1.00°, 44.37° ± 1.00°, 47.22° ± 1.00°, and 51.70° ± 1.00°. These diffraction peaks are derived from the argyrodite-type crystal phase.

[0082] The position of the diffraction peak is expressed as ±1.00° from the center, but the position of the diffraction peak is preferably ±0.500° from the center, and more preferably ±0.300° from the center.

[0083] It should be noted that the aforementioned diffraction peaks are observed when measuring the iron-containing compound alone before it is composited with the conductive material, but are not observed, or are sometimes only slightly observed, in the active material of the present invention. The present inventors believe that this is because the composited iron-containing compound and the conductive material changes the crystal structure of the iron-containing compound.

[0084] The aforementioned iron-containing compound may also contain other materials or other components as needed. Therefore, the aforementioned iron-containing compound may contain a single phase consisting of a crystalline phase of an argyrodite-type crystal structure, or may also contain other phases in addition to this phase. For example, in addition to the crystalline phase of the argyrodite-type crystal structure, it may also contain a Li2S phase, a Li3PS4 phase, a Li4P2S6 phase, a Li2FeS2 phase, a FeS phase, a LiCl or LiBr phase, etc. In particular, from the perspective of increasing the capacity of the active material of the present invention, the aforementioned iron-containing compound preferably contains a Li2S phase in addition to the crystalline phase of the argyrodite-type crystal structure.

[0085] In particular, the iron-containing compound, before being composited with the conductive material, preferably contains Li, S, P, Fe, and X, and includes a crystal phase having an argyrodite-type crystal structure. In addition to the other materials and components described above, the compound may also contain impurities that have a minimal effect on the effects of the present invention, for example, less than 5% by mass, particularly less than 3% by mass.

[0086] In the aforementioned iron-containing compound, the content of Li in the iron-containing compound is preferably, for example, 10% by mass or greater, more preferably 12% by mass or greater, and even more preferably 15% by mass or greater. On the other hand, the content is preferably, for example, 25% by mass or less, more preferably 23% by mass or less, and even more preferably 21% by mass or less. By setting the content of Li within this range, the capacity of a battery comprising the active material of the present invention can be further increased.

[0087] As the conductive material, a material with electronic conductivity can be used without particular limitation. As the conductive material, for example, various metal materials and conductive non-metallic materials can be mentioned. Metal materials and conductive non-metallic materials can use any of these, or the two can be used in combination. As the aforementioned metal material, various noble metal elements can be mentioned, such as gold (Au) element, silver (Ag) element, platinum (Pt) element, palladium (Pd) element, rhodium (Rh) element, iridium (Ir) element, ruthenium (Ru) element and osmium (Os) element, etc. In addition, various transition metal elements can be mentioned, such as copper (Cu) element, iron (Fe) element and tin (Sn) element, etc. These metal elements can be used alone or in combination of two or more.

[0088] As the conductive non-metallic material, for example, a carbon material can be used. Examples thereof include graphite, acetylene black, carbon black, carbon nanofibers, carbon nanotubes, nanographene, and fullerene nanowhiskers. These carbon materials can be used alone or in combination of two or more.

[0089] The various conductive materials mentioned above serve as electron conduction paths when lithium is desorbed or absorbed from the iron-containing compound, and therefore are preferably uniformly dispersed and closely adhered to the surface and interior of the iron-containing compound.

[0090] From the perspective of uniformly dispersing the conductive material particles on the surface and within the iron-containing compound particles, the size of the conductive material is preferably smaller than that of the iron-containing compound. Specifically, when the particle size of the iron-containing compound is defined as D1 and the particle size of the conductive material is defined as D2, the value of D1 / D2 is, for example, preferably 2 or greater, more preferably 5 or greater, and even more preferably 10 or greater. On the other hand, the value of D1 / D2 is, for example, preferably 1000 or less, more preferably 500 or less, and even more preferably 10 or more and 100 or less.

[0091] The particle size D1 of the iron-containing compound is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 0.5 μm or more. Meanwhile, D1 is preferably 20 μm or less, more preferably 10 μm or less, and even more preferably 5 μm or less.

[0092] The particle size D2 of the conductive material is preferably 1 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more. On the other hand, D2 is preferably 500 nm or less, more preferably 300 nm or less, and even more preferably 200 nm or less.

[0093] The particle size of the iron-containing compound is the cumulative volume particle size D at 50% of the cumulative volume measured by laser diffraction scattering particle size distribution measurement.50 (hereinafter referred to as "D 50 ” refers to the particle size).

[0094] On the other hand, when the conductive material is dispersed within the particles of the aforementioned iron-containing compound, it is difficult to determine the particle size of the conductive material using laser diffraction and scattering particle size distribution analysis. Therefore, the particle size is determined by directly observing the conductive material dispersed within the aforementioned iron-containing compound using a SEM (scanning electron microscope) or a TEM (transmission electron microscope). It should be noted that, for example, when the conductive material is the aforementioned carbon nanotubes or carbon nanofibers, the particle size is determined by measuring the diameter of the fiber cross section or the average of the major and minor diameters, i.e., the fiber diameter.

[0095] The active material of the present invention has a diffraction peak at a specific angle when it is measured using an X-ray diffraction device. Specifically, in the X-ray diffraction pattern measured by an X-ray diffraction device using CuKα1 rays, there are diffraction peaks at 2θ=27.1°±0.5° and 31.4°±0.5°. By having such diffraction peaks, the initial discharge capacity of the battery containing the active material of the present invention is increased, and a high capacity can be maintained even when discharged at a high rate. In this case, typically, the active material of the present invention does not observe any peaks derived from the argyrodite-type crystal phase, or even if observed, they are extremely weak. It should be noted that it can be inferred that the diffraction peaks appearing at the aforementioned angles are diffraction peaks caused by lithium sulfide.

[0096] It should be noted that, in this specification, “does not have a diffraction peak derived from an argyrodite-type crystal phase” means that the diffraction peak is not observed when the active material is measured by an X-ray diffraction device using CuKα1 rays as described above, but does not include the case where an argyrodite-type crystal phase is observed in the local structure in other measurement methods such as measurements based on total X-ray scattering and pair distribution function (PDF) analysis.

[0097] In the active material of the present invention, the amount of the conductive material per 100 parts by mass of the iron-containing compound is, for example, preferably 1 part by mass or more, more preferably 2 parts by mass or more, and even more preferably 5 parts by mass or more. On the other hand, the amount of the conductive material per 100 parts by mass of the iron-containing compound is, for example, preferably 50 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less. By containing the iron-containing compound and the conductive material within this range, a battery comprising the active material of the present invention can maintain a high capacity even when discharged at a high rate.

[0098] According to the present invention, in addition to the above-mentioned active material, a solid electrolyte is also provided. The solid electrolyte of the present invention contains the aforementioned iron-containing compound used in the above-mentioned active material. Therefore, the solid electrolyte of the present invention is also called an "iron-containing solid electrolyte". The details of the iron-containing solid electrolyte are the same as the details of the aforementioned iron-containing compound, and detailed description is omitted here. If the iron-containing solid electrolyte of the present invention is summarized, the iron-containing solid electrolyte contains the aforementioned iron-containing compound containing Li element, S element, P element, Fe element and X element, and each element satisfies the relationship formula (1) to (4) related to the above-mentioned composition. This iron-containing solid electrolyte is given electronic conductivity, so the iron-containing solid electrolyte is particularly used in the positive electrode layer, thereby improving the overall electronic conductivity of the positive electrode layer. As a result, the battery using the iron-containing solid electrolyte becomes a battery with excellent battery performance such as capacity and rate characteristics.

[0099] It should be noted that the iron-containing solid electrolyte of the present invention is not composited with a conductive material and therefore does not necessarily exhibit the diffraction peak observed in the active material of the present invention. However, the appearance of such a peak due to the manufacturing method, etc., is not excluded.

[0100] Next, a preferred method for producing the active material and iron-containing solid electrolyte of the present invention will be described. This production method is broadly divided into a first step of preparing the aforementioned iron-containing compound particles; and a second step of mixing the iron-containing compound particles with particles of a conductive material to form a composite. When producing an iron-containing solid electrolyte, only the first step is included, omitting the second step. Each step is described below.

[0101] In the first step, particles of the iron-containing compound are prepared. The particles contain the elements described above and include a crystal phase having an argyrodite-type crystal structure. The iron-containing compound can be produced by a known method. When the compound contains, for example, Li, P, S, Fe, Cl, and Br, lithium sulfide (Li2S) powder, phosphorus pentasulfide (P2S5) powder, ferrous sulfide (FeS) powder, lithium chloride (LiCl) powder, and lithium bromide (LiBr) powder are mixed and calcined to obtain the particles of the iron-containing compound. These powders are preferably mixed using, for example, a ball mill, a bead mill, or a homogenizer.

[0102] After mixing to obtain a mixed powder as described above, the mixed powder is dried as needed, then calcined in an inert atmosphere or under the circulation of hydrogen sulfide gas (H2S), and crushed and classified as needed to obtain the above-mentioned iron-containing compound.

[0103] The firing temperature in an atmosphere containing hydrogen sulfide gas is preferably 350° C. or higher, more preferably 450° C. or higher. On the other hand, the firing temperature is preferably 650° C. or lower, more preferably 600° C. or lower, and even more preferably 500° C. or lower.

[0104] On the other hand, when firing in an inert atmosphere such as nitrogen or a rare gas, the firing temperature is preferably 350° C. or higher, for example. On the other hand, the firing temperature is preferably 550° C. or lower, more preferably 500° C. or lower, and even more preferably 450° C. or lower.

[0105] The particles of the iron compound can also be produced by mechanically grinding the raw material powder to amorphize it, and then, if necessary, heat-treating the amorphized raw material powder to crystallize it. In this case, as long as the raw material powder can be fully mixed and amorphized, the processing device and processing conditions are not particularly limited. In particular, when a planetary ball mill is used, the container filled with the raw material powder rotates / revolves at high speed, so high impact energy is generated between the grinding media, i.e., the balls, which are loaded into the container together with the raw material powder, and the raw material powder can be efficiently and uniformly amorphized. The mechanical grinding method can be either dry or wet.

[0106] The processing conditions for the mechanical milling method can be appropriately set according to the processing equipment used. For example, the processing time is 0.1 hours to 100 hours, which can make the raw material powder more efficiently and uniformly amorphized. The balls used as the grinding medium are preferably made of ZrO2, Al2O3, Si3N4 (silicon nitride), or WC (tungsten carbide), and the ball diameter is preferably about 0.2 mm to 10 mm.

[0107] The iron-containing compound can be obtained by heat-treating the raw material powder, which has been rendered amorphous by mechanical milling, under the same firing conditions as described above to crystallize it. The raw material powder that has been mechanically milled is more uniformly mixed than raw material powders obtained by conventional pulverization and mixing, allowing the heat treatment temperature to be further lowered.

[0108] The iron-containing compound particles can also be produced by a liquid-phase method using an organic solvent. In this case, the sulfide or halide used as the raw material for the iron-containing compound is dissolved in a solvent such as tetrahydrofuran or ethanol, and the iron-containing compound is precipitated using the solvent as a reaction field. Alternatively, the iron-containing compound can be synthesized by another method, dissolved in a solvent such as ethanol, and then precipitated. Compared to other methods, this liquid-phase method allows the production of iron-containing compound particles in a shorter time and with less energy. Furthermore, the particles can be relatively easily reduced in size.

[0109] After the iron-containing compound particles are obtained, they are preferably adjusted to an appropriate particle size. The preferred particle size of the iron-containing compound can be the same as that described above, and thus description thereof is omitted here.

[0110] The iron-containing solid electrolyte of the present invention can be obtained through the first step described above.

[0111] Next, in order to obtain the active material of the present invention, a second step is carried out in which the iron-containing compound is mixed with a conductive material to form a composite. The details of the conductive material used have been described above and will not be described here.

[0112] The iron-containing compound and the conductive material can be composited, for example, by applying mechanical energy to the iron-containing compound particles and the conductive material particles. For this purpose, it is preferred to apply a compressive / impact force, or a shearing / frictional force, to the iron-containing compound and the conductive material while they are mixed.

[0113] In order to impart mechanical energy such as compression / impact, shear / friction to the mixed iron-containing compound and the conductive material to form a composite, it is preferred to use an apparatus that is mainly used for stirring, mixing, kneading, granulating, crushing, dispersing and / or surface modification of the powder. For example, a planetary ball mill, a ball mill, a jet mill, a bead mill, a stirring type crusher, a vibration mill, a hammer mill, a roller mill and an atomizer can be used. The type of main mechanical energy that can be imparted when using these devices will vary depending on the device. For example, when using a planetary ball mill, by mainly applying compression / impact to the mixed compound and the conductive material, the two can be composited. The centrifugal acceleration obtained when the device rotates is not particularly limited as long as it is a degree that can cause the compound and the conductive material to form a composite. For example, it is preferably 10G or more, more preferably 15G or more, and even more preferably 18G or more. In addition, the centrifugal acceleration is, for example, preferably 40G or less, more preferably 30G or less, and even more preferably 25G or less. When the centrifugal acceleration is within the aforementioned range, the effects of the present invention can be more pronounced.

[0114] Alternatively, the aforementioned liquid phase method can be used to form a composite of the iron-containing compound and the conductive material. In this case, the conductive material is preliminarily dispersed in an organic solvent, and then the raw material for the iron-containing compound and the iron-containing compound are added to the organic solvent. This allows the iron-containing compound to precipitate on the surface or within the conductive material, thereby forming a composite. This composite method can further reduce the particle size of the composited particles.

[0115] The active material of the present invention obtained by the above various manufacturing methods can be made into an electrode mixture by mixing it with an electrolyte, a conductive material, a binder, etc. When the active material of the present invention is used as a positive electrode active material, the electrode mixture becomes a positive electrode mixture constituting a positive electrode layer.

[0116] The aforementioned electrolyte may be a solid electrolyte. The solid electrolyte may be different from the iron-containing solid electrolyte of the present invention described previously, or it may be the same therewith. In the case where the solid electrolyte is different from the iron-containing solid electrolyte, the solid electrolyte preferably has ion conductivity such as lithium ion conductivity. Specifically, for example, inorganic solid electrolytes such as sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, and halide solid electrolytes; and organic polymer electrolytes such as polymer electrolytes. From the viewpoint of being able to make the effect of the active material of the present invention more significant, the solid electrolyte is preferably a sulfide solid electrolyte. For the sulfide solid electrolyte, it can be the same as the sulfide solid electrolyte used in conventional solid-state batteries. The sulfide solid electrolyte may, for example, contain Li and S elements and have lithium ion conductivity.

[0117] Sulfide solid electrolytes can be crystalline materials, glass ceramics, or glass. Sulfide solid electrolytes can also have an argyrodite-type crystal structure. Examples of such sulfide solid electrolytes include: Li2S-P2S5, Li2S-P2S5-LiX ("X" represents one or more halogen elements), Li2S-P2S5-P2O5, Li2S-Li3PO4-P2S5, Li3PS4, Li4P2S6, Li 10 GeP2S 12 、Li 3.25 Ge 0.25 P 0.75 S4、Li7P3S 11 、Li 3.25 P 0.95 S4, Li a PS b X c("X" represents one or more halogen elements. a represents a number from 3.0 to 9.0. b represents a number from 3.5 to 6.0. c represents a number from 0.1 to 3.0). Examples of the sulfide solid electrolytes include those described in International Publication No. 2013 / 099834 and International Publication No. 2015 / 001818. The solid electrolyte of the present invention can also be used as the sulfide solid electrolyte.

[0118] The active material contained in the electrode mixture can be only the active material of the present invention, or it can be used in combination with other active materials. As other active materials, known sulfur elements and active materials containing sulfur can be cited. The ratio of the active material of the present invention in the electrode mixture can be, for example, 20% by mass or more, 30% by mass or more, or 40% by mass or more. On the other hand, the above ratio can be, for example, 70% by mass or less, or 60% by mass or less.

[0119] The battery of the present invention preferably comprises: a positive electrode layer containing a positive electrode active material; a negative electrode layer containing a negative electrode active material; and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer and containing a solid electrolyte, wherein the positive electrode active material is the active material described above. Furthermore, in the battery of the present invention, the solid electrolyte layer preferably contains the solid electrolyte of the present invention.

[0120] The battery of the present invention can be produced, for example, by stacking the three layers of the positive electrode layer, solid electrolyte layer, and negative electrode layer produced as described above and performing pressure molding.

[0121] The battery having the active material and / or solid electrolyte of the present invention is preferably a lithium ion battery. As such a battery, a solid-state battery having a solid electrolyte layer, in particular an all-solid-state battery, can be cited. In addition, the battery of the present invention may be a primary battery or a secondary battery, wherein it is preferably used in a secondary battery, particularly preferably in a lithium secondary battery. “Lithium secondary battery” broadly includes the meaning of a secondary battery that is charged and discharged by the movement of lithium ions between a positive electrode and a negative electrode.

[0122] In addition to solid-state batteries that do not contain any liquid or gel-like substances as electrolytes, "solid-state batteries" also include those that contain liquid or gel-like substances as electrolytes, for example, less than 50 mass%, less than 30 mass%, or less than 10 mass%.

[0123] With respect to the above-mentioned embodiment, the present invention further discloses the following active materials and solid electrolytes.

[0124] [1]

[0125] An active material comprising a compound and a conductive material,

[0126] The aforementioned compound contains lithium (Li) element, sulfur (S) element, phosphorus (P) element, iron (Fe) element and halogen (X) element,

[0127] In the X-ray diffraction pattern measured by an X-ray diffraction apparatus using CuKα1 rays, there are peaks at positions of 2θ=27.1°±0.5° and 31.4°±0.5°.

[0128] The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship equations (1) to (4).

[0129] (1)5.8≤Li / (Fe+P)≤10.0

[0130] (2)0.1≤X / (Fe+P)≤1.4

[0131] (3)0.2≤X+Fe≤2.0

[0132] (4) 0.0<Fe / (Fe+P)<1.0

[0133] [2]

[0134] The active material according to [1], wherein the compound is composited with the conductive material.

[0135] 〔3〕

[0136] The active material according to [1] or [2], wherein the conductive material is contained in an amount of 1 part by mass to 50 parts by mass based on 100 parts by mass of the compound.

[0137] [4]

[0138] The active material according to any one of [1] to [3], wherein the conductive material is at least one of a carbon material and a metal material.

[0139] 〔5〕

[0140] A solid electrolyte comprising a compound containing lithium (Li), sulfur (S), phosphorus (P), iron (Fe) and a halogen (X).

[0141] The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship.

[0142] (1)5.8≤Li / (Fe+P)≤10.0

[0143] (2)0.1≤X / (Fe+P)≤1.4

[0144] (3)0.2≤X+Fe≤2.0

[0145] (4) 0.0<Fe / (Fe+P)<1.0

[0146] [6]

[0147] The solid electrolyte according to [5], wherein the cumulative volume particle size D of the compound at 50% by volume obtained by laser diffraction scattering particle size distribution measurement is 50 It is 0.1 μm or more and 20 μm or less.

[0148] [7]

[0149] The solid electrolyte according to [5] or [6], wherein the compound is composed of the formula Li a Fe d P e M 1-d-e S b X c (Wherein, M is at least one element selected from germanium (Ge), antimony (Sb), silicon (Si), tin (Sn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co) and manganese (Mn). a is greater than or equal to 5.8 and less than or equal to 10.0. b is greater than or equal to 3.5 and less than or equal to 6.0. c is greater than or equal to 0.1 and less than or equal to 1. With d+e being less than or equal to 1, d and e are each independently a number greater than 0 and less than 1.)

[0150] 〔8〕

[0151] The solid electrolyte according to any one of [5] to [7], wherein the content of lithium element in the compound is 10% by mass or more and 25% by mass or less.

[0152] 〔9〕

[0153] An electrode mixture comprising the active material described in any one of [1] to [4] and a sulfide solid electrolyte.

[0154]

[10]

[0155] A battery comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer.

[0156] The positive electrode layer contains the active material described in any one of [1] to [4].

[0157]

[11]

[0158] A battery comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer.

[0159] The solid electrolyte layer contains the solid electrolyte described in any one of [5] to [8].

[0160] Example

[0161] The present invention will be described in more detail below by way of examples. However, the scope of the present invention is not limited to the examples. Unless otherwise specified, "%" and "parts" refer to "mass %" and "mass parts" respectively.

[0162] [Example 1]

[0163] Lithium sulfide (Li2S) powder, phosphorus pentasulfide (P2S5) powder, ferrous sulfide (FeS) powder, and lithium chloride (LiCl) powder were weighed so as to achieve the composition shown in Table 1 below. The powders were mixed and crushed using a planetary ball mill (FRITSCH, P-7) at 500 rpm for 20 hours to prepare a mixed powder.

[0164] The mixed powder was filled in a carbon container, and heated in a tubular electric furnace at a heating rate of 200°C / h while hydrogen sulfide gas (H2S, purity 100%) was flowing at 1.0 L / min, and calcined at 500°C for 4 hours.

[0165] The calcined product was then crushed with a mortar, pulverized with a ball mill, and sized with a sieve having a mesh size of 53 μm to obtain a particle size of D 50 The iron-containing compound (solid electrolyte) was in a powdery state of 6.5 μm. As a result of XRD measurement, it was confirmed that the iron-containing compound (solid electrolyte) had a crystal phase of an argyrodite-type crystal structure.

[0166] Carbon nanotubes (VGCF (registered trademark)-H manufactured by Showa Denko) were used as the conductive material. The particle size D 500.04 μm. 83.3 parts of the aforementioned iron-containing compound and 16.7 parts of the conductive material were mixed and compounded using a planetary ball mill (Fritsch, P-7) at 500 rpm for 10 hours. The composite was then crushed with a mortar and sized with a sieve having a mesh size of 53 μm to obtain a particle size of D 50 The particles of the positive electrode active material are 3.2 μm.

[0167] All the above operations were carried out in a glove box that had been purged with sufficiently dried Ar gas (dew point below -60°C).

[0168] [Examples 2 to 5]

[0169] The raw material powders were mixed in such a manner as to achieve the composition shown in Table 1. A powder of the aforementioned iron-containing compound (solid electrolyte) was obtained in the same manner as in Example 1, except that the powder was mixed in such a manner as to achieve the composition shown in Table 1. As a result of XRD measurement, it was confirmed that the obtained iron-containing compound had a crystal phase having an argyrodite-type crystal structure. As a conductive material, conductive carbon black, namely Ketjen Black (registered trademark, hereinafter also referred to as "KB") EC300 manufactured by Lion Specialty Chemicals Co., Ltd., was used. 83.3 parts of the aforementioned iron-containing compound and 16.7 parts of KB were used. Particles of the active material were obtained in the same manner as in Example 1, except that the powder was mixed in such a manner as in Example 1.

[0170] [Comparative Example 1]

[0171] In this comparative example, the compounds shown in Table 1 were used instead of the aforementioned iron-containing compound. Active material particles were obtained in the same manner as in Example 1 except for the above.

[0172] [Comparative Examples 2 to 5]

[0173] The iron compound-containing powder was obtained in the same manner as in Example 2 except that the raw material powders were mixed to have the composition shown in Table 1. The active material particles were obtained in the same manner as in Example 2 except that the raw material powders were mixed to have the composition shown in Table 1.

[0174] [XRD measurement]

[0175] In a glove box purged with sufficiently dried Ar gas (dew point -60°C or lower), the active materials obtained in Examples and Comparative Examples were placed in an airtight holder not exposed to the atmosphere, and XRD measurement was performed under the following conditions.

[0176] Under the same measurement conditions, XRD measurement was also performed on the aforementioned iron-containing compound.

[0177] The XRD spectra of the active material and the above iron-containing compound are shown in Figures 1 to 10 The names of substances showing XRD peaks are shown in Table 1. Figures 1 to 10In the figure, the XRD spectrum shown by symbol (a) is about the aforementioned iron-containing compound, and the XRD spectrum shown by symbol (b) is about the active material.

[0178] Device name: Fully automatic multifunctional X-ray diffraction device SmartLab SE (manufactured by Rigaku Corporation)

[0179] Radiation source: CuKα1

[0180] Tube voltage: 40kV

[0181] Tube current: 50mA

[0182] ·Measurement method: Concentration method (reflection method)

[0183] Optical system: Multilayer mirror divergent beam method (CBO-α)

[0184] Detector: One-dimensional semiconductor detector

[0185] ·Incident Soller gap: Soller gap 2.5°

[0186] Length limit slit: 10mm

[0187] Soller gap: 2.5°

[0188] Entrance slit: 1 / 6°

[0189] Light receiving slit: 2mm (open)

[0190] Measuring range: 2θ = 10 to 120°

[0191] Stride length: 0.02°

[0192] Scanning speed: 1.0° / min

[0193] Next, solid-state battery cells were fabricated using the active materials produced in Examples and Comparative Examples as positive electrode active materials, and the initial discharge capacities were measured by the following method. The results are shown in Table 1.

[0194] Production of solid-state battery cells

[0195] The active materials prepared in Examples and Comparative Examples were used as positive electrode active materials, and Li 5.4 PS 4.4 Cl 0.8 Br 0.8 A solid-state battery was produced using In-Li as the negative electrode active material in the negative electrode layer and the solid electrolyte powder used in the positive electrode layer and the solid electrolyte layer.

[0196] (Preparation of Positive Electrode Mixture)

[0197] The positive electrode mixture for the positive electrode layer was prepared by mixing the active material powder obtained in Examples and Comparative Examples with the solid electrolyte powder in a mortar at a mass ratio of 60:40.

[0198] (Fabrication of solid-state battery cells)

[0199] The lower opening of a polypropylene cylinder (opening diameter 10.5mm, height 18mm) with upper and lower openings is blocked with a negative electrode (SUS), a solid electrolyte powder is placed on it, and a positive electrode (SUS) is blocked, and then uniaxially pressed at 200MPa to form a solid electrolyte layer. Next, the positive electrode is temporarily removed, a positive electrode mixture is placed on the solid electrolyte layer, and the positive electrode is blocked again, and then uniaxially pressed at 560MPa to stack the positive and solid electrolyte layers. Thereafter, the cylinder is turned upside down, the negative electrode is temporarily removed, an In-Li foil is placed on the solid electrolyte layer, and the negative electrode is blocked again. Finally, a vise is used to clamp the positive and negative electrodes with a load of 6N·m to produce a solid-state battery cell stacked with a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. It should be noted that the thickness of each layer is approximately 40 μm for the positive electrode layer, 600 μm for the solid electrolyte layer, and 400 μm for the negative electrode layer. The solid-state battery cell was produced in a glove box purged with argon gas at a dew point of -60°C. In an environmental testing machine maintained at 25°C, the produced solid-state battery was connected to a charge and discharge measurement device to evaluate the battery characteristics. It should be noted that the current of 2.0 mA during charge and discharge was set as a 1C rate.

[0200] 〔Initial discharge capacity〕

[0201] In the initial charge and discharge cycle (first cycle), the battery was charged to 3.0 V at 0.03 C using the CC-CV method and discharged to 0.38 V at 0.03 C using the CC method to efficiently desorb and store lithium ions contained in the positive electrode active material. In the second cycle, the battery was charged to 3.0 V at 0.1 C using the CC-CV method and discharged to 0.38 V at 0.1 C using the CC-CV method. The charge and discharge capacity of the second cycle was used as the initial discharge capacity.

[0202] 〔5C / 0.1C discharge maintenance rate (%)〕

[0203] In the same manner as the measurement of the initial discharge capacity, the third cycle of charge and discharge was performed at 0.1C. In the fourth cycle and thereafter, charge and discharge were performed at a rate of 0.2C (4th cycle), 0.5C (5th cycle), 1C (6th cycle), 2C (7th cycle) and 5C (8th cycle). When the discharge capacity (0.1C) of the second cycle was set to 100%, the ratio of the discharge capacity (8th cycle) of 5C was taken as the 5C / 0.1C discharge maintenance rate. The charge and discharge curves of the batteries using the active materials prepared in Examples 1 and 5 and Comparative Examples 2 and 4 are shown in FIG. Figures 11 to 14 .

[0204] Next, the lithium ion conductivity of the iron-containing solid electrolytes (iron-containing compounds) obtained in Examples and Comparative Examples was measured by the following method. The results are also shown in Table 1.

[0205] [Measurement of Lithium Ion Conductivity of Iron-Containing Solid Electrolytes]

[0206] In a glove box purged with sufficiently dried Ar gas (dew point below -60°C), the iron-containing solid electrolyte powders obtained in Examples and Comparative Examples were subjected to a pressure of about 6 t / cm 2 Samples for measuring lithium ion conductivity were prepared by uniaxial press forming with a load of 10 mm to produce pellets with a diameter of 10 mm and a thickness of approximately 1 mm to 8 mm. Lithium ion conductivity measurements were performed using a Solartron 1255B electrochemical measurement system (1280C) and an impedance / gain / phase analyzer (SI 1260) manufactured by Solartron Analytical. Measurement conditions were AC impedance spectroscopy at a temperature of 25°C, a frequency of 100 Hz to 1 MHz, and an amplitude of 100 mV.

[0207] [Table 1]

[0208]

[0209] From the results shown in Table 1, it can be seen that the battery using the active material prepared in each example as the positive electrode active material can achieve both the initial discharge capacity and the 5C / 0.1C discharge maintenance rate.

[0210] The iron-containing solid electrolytes produced in each embodiment have a 1×10 -4 S / cm or higher. The iron-containing solid electrolytes manufactured in each embodiment are endowed with electronic conductivity as a whole, so their use in the positive electrode layer can improve the lithium ion conductivity and electronic conductivity of the entire positive electrode layer, thereby exhibiting good battery characteristics.

[0211] Industrial applicability

[0212] As described above in detail, the active material and solid electrolyte according to the present invention can improve the performance of lithium-ion batteries.

Claims

1. An active material comprising a compound and a conductive material, The compound contains lithium (Li) element, sulfur (S) element, phosphorus (P) element, iron (Fe) element and halogen (X) element, In the X-ray diffraction pattern measured by an X-ray diffraction apparatus using CuKα1 rays, there are peaks at positions of 2θ=27.1°±0.5° and 31.4°±0.5°. The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship formulas (1) to (4). (1)5.8≤Li / (Fe+P)≤10.0 (2)0.1≤X / (Fe+P)≤1.4 (3)0.2≤X+Fe≤2.0 (4)0.0<Fe / (Fe+P)<1.

0.

2. The active material according to claim 1, wherein The compound is composited with the conductive material.

3. The active material according to claim 1 or 2, wherein The conductive material is contained in an amount of 1 part by mass or more and 50 parts by mass or less relative to 100 parts by mass of the compound.

4. The active material according to claim 1 or 2, wherein The conductive material is at least one of a carbon material and a metal material.

5. A solid electrolyte comprising a compound containing lithium (Li), sulfur (S), phosphorus (P), iron (Fe) and a halogen (X). The molar ratio of the lithium (Li) element to the sum of the iron (Fe) element and the phosphorus (P) element, the molar ratio of the halogen (X) element to the sum of the iron (Fe) element and the phosphorus (P) element, the sum of the molar numbers of the halogen (X) element and the iron (Fe) element, and the molar ratio of the iron (Fe) element to the sum of the iron (Fe) element and the phosphorus (P) element satisfy the following relationship: (1)5.8≤Li / (Fe+P)≤10.0 (2)0.1≤X / (Fe+P)≤1.4 (3)0.2≤X+Fe≤2.0 (4)0.0<Fe / (Fe+P)<1.

0.

6. The solid electrolyte according to claim 5, wherein The cumulative volume particle size D at 50% of the cumulative volume obtained by laser diffraction scattering particle size distribution measurement of the compound is: 50 It is 0.1 μm or more and 20 μm or less.

7. The solid electrolyte according to claim 5 or 6, wherein The compound is composed of the formula Li a Fe d P e M 1-d-e S b X c Represented by the formula, wherein M is at least one element selected from germanium (Ge), antimony (Sb), silicon (Si), tin (Sn), aluminum (Al), titanium (Ti), nickel (Ni), cobalt (Co) and manganese (Mn), a is greater than 5.8 and less than 10.0, b is greater than 3.5 and less than 6.0, c is greater than 0.1 and less than 1.4, and under the condition that d+e is less than 1, d and e are each independently a number greater than 0 and less than 1.

8. The solid electrolyte according to claim 5 or 6, wherein The content of lithium element in the compound is 10 mass % or more and 25 mass % or less. 9 . An electrode mixture comprising the active material according to claim 1 or 2 and a sulfide solid electrolyte.

10. A battery comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, The positive electrode layer contains the active material according to claim 1 or 2.

11. A battery comprising a positive electrode layer, a negative electrode layer, and a solid electrolyte layer located between the positive electrode layer and the negative electrode layer, The solid electrolyte layer contains the solid electrolyte according to claim 5 .

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