Battery material and battery

Abstract

The invention relates to a composite material and a battery. The main purpose of the present invention is to provide a composite material with which it is possible to obtain an electrode layer and an electrolyte layer having good ionic conductivity. The present disclosure solves the problem by providing a composite material containing a first solid electrolyte and a second solid electrolyte, the first solid electrolyte and the second solid electrolyte containing Li, P, and S and having an argyrodite-type crystal structure, the first solid electrolyte containing an anionic component containing B, and the second solid electrolyte containing an anionic component containing C, and the second solid electrolyte containing Li, P, and S, and having an argyrodite-type crystal structure. The second solid electrolyte does not contain an anionic component containing B.

Description

Technical Field

[0001] This disclosure relates to composite materials and batteries. Background Technology

[0002] In recent years, battery development has been booming. For example, in the automotive industry, the development of batteries for battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), or hybrid electric vehicles (HEVs) is progressing. Furthermore, inorganic solid electrolytes are known as electrolytes used in batteries. Inorganic solid electrolytes, for example, have the advantage of being easier to simplify safety devices compared to electrolytes (liquid electrolytes) containing flammable organic solvents.

[0003] For example, Patent Document 1 discloses a solid electrolyte material containing Li, T, X, and A. T contains at least one element selected from Sb, P, As, Si, Ge, Al, B, and W. X contains one or more halogens, halogen-like elements, or N. A contains one or more of S or Se. The solid electrolyte material has peaks at 2θ = 14.5°±0.50°, 16.8°±0.50°, 23.9°±0.50°, 28.1°±0.50°, and 32.5°±0.50° in X-ray diffraction measurements using Cu-Kα(1,2) = 1.54064.

[0004] Patent document 2 discloses a compound having the formula: Li 7-x PS 6-x X x-z (BH4)z (where X is selected from Cl, Br, I, F and CN, and 0 < x ≤ 2 and 0 < z ≤ 0.50) represents the expression.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2023-543227

[0008] Patent Document 2: Japanese Patent Publication No. 2020-534245 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] From the viewpoint of improving battery performance, it is preferable that the electrode layer and electrolyte layer have good ionic conductivity. This disclosure was made in view of the above-mentioned circumstances, and its main objective is to provide a composite material for obtaining an electrode layer and electrolyte layer with good ionic conductivity.

[0011] Methods for solving problems

[0012] [1] The composite material is a composite material containing a first solid electrolyte and a second solid electrolyte, wherein the first solid electrolyte and the second solid electrolyte contain Li, P and S and have a crystal structure of silver sulfide-germanium ore type, wherein the first solid electrolyte contains an anionic component containing B and the second solid electrolyte does not contain an anionic component containing B.

[0013] [2] According to the composite material described in [1], wherein the anionic component containing B is BH4. - .

[0014] [3] According to the composite material described in [1] or [2], wherein the proportion of the first solid electrolyte is 7.0% by weight or more and 75.0% by weight or less relative to the total of the first solid electrolyte and the second solid electrolyte.

[0015] [4] The composite material according to any one of [1] to [3], wherein the proportion of the first solid electrolyte is 15.0% by weight or more and 60.0% by weight or less relative to the total of the first solid electrolyte and the second solid electrolyte.

[0016] [5] The composite material according to any one of [1] to [4], wherein the second solid electrolyte contains a halogen as an anionic component.

[0017] [6] According to the composite material described in [5], wherein the second solid electrolyte contains at least one of Cl and Br as the halogen.

[0018] [7] The composite material according to any one of [1] to [6], wherein the composite material contains an electrode active material.

[0019] [8] According to the composite material described in [7], wherein the electrode active material contains a negative electrode active material.

[0020] [9] According to the composite material described in [7], wherein the electrode active material contains a positive electrode active material.

[0021]

[10] A battery having a positive active material layer, a negative active material layer, and an electrolyte layer disposed between the positive active material layer and the negative active material layer, wherein at least one of the positive active material layer, the negative active material layer and the electrolyte layer contains a composite material according to any one of [1] to [9].

[0022] Invention Effects

[0023] This disclosure achieves the effect of providing a composite material that yields an electrode layer and an electrolyte layer with good ionic conductivity. Attached Figure Description

[0024] Figure 1 A schematic cross-sectional view of the battery in this disclosure is shown as an example.

[0025] Figure 2 A coordinate graph showing the results of the embodiments and comparative examples.

[0026] Explanation of reference numerals in the attached figures

[0027] 1…Positive electrode active material layer

[0028] 2…Negative electrode active material layer

[0029] 3…Electrolyte layer

[0030] 4…Positive current collector

[0031] 5… Negative current collector

[0032] 10… batteries Detailed Implementation

[0033] The following describes in detail the composite materials and batteries used in this disclosure. It should be noted that the accompanying drawings are schematic representations, and the size and shape of the parts are exaggerated as appropriate for ease of understanding.

[0034] A. Composite materials

[0035] The composite material disclosed herein contains a first solid electrolyte and a second solid electrolyte. Both the first and second solid electrolytes contain Li, P, and S, and have a steric sulfide-germanium-type crystal structure. Furthermore, the first solid electrolyte contains a boron-containing anion, while the second solid electrolyte does not contain a boron-containing anion.

[0036] The composite material disclosed herein contains a specified first solid electrolyte and a second solid electrolyte, thereby enabling good ionic conductivity in the electrode layer and the electrolyte layer.

[0037] Solid electrolytes with a sulforaphane-germanium-type crystal structure (sulforaphane-germanium-type solid electrolytes) are known to have good ionic conductivity (bulk ionic conductivity). Furthermore, when using solid electrolytes with a crystalline structure (crystalline solid electrolytes) in batteries, they are generally micronized. However, since crystalline solid electrolytes are relatively hard, micronization can create gaps between the solid electrolytes themselves and between the solid electrolyte and the electrode active material, potentially increasing interfacial resistance. In contrast, sulforaphane-germanium-type solid electrolytes (first solid electrolytes), which contain boron anions, are considered to have lower bulk ionic conductivity than other sulforaphane-germanium-type solid electrolytes, but are considered to be relatively soft. Therefore, by including the first solid electrolyte in the composite material, these gaps can be filled, resulting in an improvement in the overall ionic conductivity of the composite material. Additionally, since the composite material contains the first solid electrolyte, the electrode layer filling rate can be increased, which is also considered an advantage that could contribute to higher battery capacity.

[0038] 1. First solid electrolyte

[0039] The first solid electrolyte contains Li, P, and S, and has a sulfide-germanium ore-type crystal structure. Furthermore, the first solid electrolyte contains anionic components including boron (B). It should be noted that the first solid electrolyte is a different type of electrolyte from the second solid electrolyte described later; typically, as an anionic component, it does not contain halogens. Since the first solid electrolyte contains S, it is generally equivalent to a sulfide solid electrolyte. The same applies to the second solid electrolyte described later.

[0040] Examples of anionic components containing B include BH4. - BO3 - B(OH)4- and B4O7 2- Of these, the first solid electrolyte preferably contains BH4. - As an anionic component.

[0041] The first solid electrolyte may contain BH4. - It may be a main component of the anionic component, or it may not contain it as a main component. The term "main component containing it as an anionic component" refers to BH4 relative to all the anionic components contained in the first solid electrolyte. - The proportion is 50 mol% or more. Furthermore, the first solid electrolyte preferably contains PS4. 3- As an anionic component. Relative to BH4 - and PS4 3- In total, PS4 3- The proportion, for example, is 20 mol% or more, and can be 25% or more. On the other hand, PS4 3-The proportion may be less than 50 mol%, less than 40 mol%, less than 35 mol%, or less than 30 mol%.

[0042] Examples of compositions for the first solid electrolyte include xLi3PS4-(100-x)Li y M. In this composition, x is, for example, 20 or more, and may be 25 or more. On the other hand, x is, for example, 50 or less, and may be 40 or less, or may be 35 or less. In addition, M is an anionic component containing B, and y is an arbitrary number determined according to the valence of the anion.

[0043] The first solid electrolyte of this disclosure has a sulforaphite-germanium-type crystal structure (crystal phase). The presence of this crystal structure can be confirmed by X-ray diffraction (XRD). In CuKα XRD measurements, the first solid electrolyte preferably exhibits peaks at 2θ = 17.0° ± 0.5°, 24.1° ± 0.5°, 28.3° ± 0.5°, 29.6° ± 0.5°, and 38.6° ± 0.5°. These peaks are typical of the sulforaphite-germanium-type crystal phase. The positions of these peaks can each be within a range of ±0.3° or ±0.1°.

[0044] The first solid electrolyte in this disclosure preferably contains a crystal structure (phase) of the argyrocyanide type as the main phase. The term "main phase" refers to the crystal phase to which the highest intensity peak belongs in XRD measurements using CuKα rays.

[0045] The first solid electrolyte is typically in particle form. The average particle size (D) of the first solid electrolyte... 50 There are no particular limitations; for example, it can be 0.01 μm or more, 0.05 μm or more, 0.10 μm or more, 0.50 μm or more, or 1.0 μm or more. On the other hand, the average particle size (D) of the first solid electrolyte... 50 For example, it can be below 30μm, below 20μm, below 10μm, or below 5μm. Average particle size (D) 50 The cumulative 50% of the particle size in the volumetric reference particle size distribution using a laser diffraction particle size distribution measuring device is referred to as 50%.

[0046] The location of the first solid electrolyte in the composite is not particularly limited, but it is preferable that at least a portion of it is disposed on the surface of the second solid electrolyte (described later). Regarding the proportion of the first solid electrolyte disposed on the surface of the second solid electrolyte, relative to the total amount of the first solid electrolyte, it is, for example, 5% by volume or more, 10% by volume or more, 20% by volume or more, or 30% by volume or more. On the other hand, the proportion of the first solid electrolyte disposed on the surface of the second solid electrolyte is, for example, 90% by volume or less, 80% by volume or less, 70% by volume or less, 60% by volume or less, or 50% by volume or less. It should be noted that the first solid electrolyte can be disposed to coat the second solid electrolyte. For example, by mechanically mixing the first and second solid electrolytes, such as by mechanical grinding, a coating layer containing the first solid electrolyte can be formed on the surface of the second solid electrolyte. It is believed that by forming a coating layer, even if the proportion of the first solid electrolyte is reduced, the interfacial resistance can be well suppressed. Furthermore, since the proportion of the second solid electrolyte, which has a high bulk ionic conductivity, can be relatively increased, it is believed that the overall ionic conductivity of the composite can be improved.

[0047] The proportion (by weight) of the first solid electrolyte relative to the total of the first and second solid electrolytes is not particularly limited, and may be, for example, 3.0% by weight or more, 5.0% by weight or more, 7.0% by weight or more, 10.0% by weight or more, or 15.0% by weight or more. On the other hand, the proportion of the first solid electrolyte may be, for example, 98.0% by weight or less, 75.0% by weight or less, 60.0% by weight or less, 50.0% by weight or less, or 40.0% by weight or less.

[0048] Furthermore, there is no particular limitation on the proportion (volume ratio) of the first solid electrolyte relative to the total of the first solid electrolyte and the second solid electrolyte. For example, it may be 3.0% or more by volume, 5.0% or more by volume, 7.0% or more by volume, 10.0% or more by volume, or 15.0% or more by volume. On the other hand, the proportion of the first solid electrolyte may be, for example, 98.0% or less by volume, 75.0% or less by volume, 60.0% or less by volume, 50.0% or less by volume, or 40.0% or less by volume.

[0049] The location, weight ratio, and volume ratio of the first solid electrolyte can be calculated, for example, by SEM-EDS (Scanning Electron Microscopy / Energy Dispersive X-ray Spectrometry). For instance, regions where boron is identified can be considered regions of the first solid electrolyte, while regions where P and S are identified but not boron can be considered regions of the second solid electrolyte. Additionally, methods for analyzing elemental distribution using TOF-SIMS (Time-of-Flight Secondary Ion Mass Analyzer) can also be cited.

[0050] 2. Second solid electrolyte

[0051] The second solid electrolyte is a solid electrolyte containing Li, P, and S and having a steric argillaceous crystal structure. Furthermore, the second solid electrolyte does not contain any boron-containing anions. Regarding the anion components, it is the same as described in "1. First Solid Electrolyte". The phrase "does not contain any boron-containing anions" means that, for example, BH4 is not identified in the energy spectrum obtained by XPS (X-ray photoelectron spectroscopy). - Peaks containing anionic components such as B.

[0052] Furthermore, the second solid electrolyte preferably contains a halogen (halogen ion) as an anionic component. This is because it results in a second solid electrolyte with good ionic conductivity. Examples of halogens include F, Cl, Br, and I. The second solid electrolyte may contain one halogen or two or more halogens. Among these, the second solid electrolyte preferably contains at least one of Cl and Br. Additionally, it may contain the aforementioned halogen as a main component of the anionic component, or it may not contain it as a main component. The term "main component" is the same as described in "1. First Solid Electrolyte". Furthermore, the second solid electrolyte preferably has PS4. 3- As an anionic component. Compared to halogens and PS4. 3- In total, PS4 3- The proportion, for example, is 10 mol% or more, 20 mol% or more, or 30 mol% or more. On the other hand, PS4... 3- The proportion is, for example, less than 50 mol%, or less than 40 mol%.

[0053] Examples of compositions that are halogen-free second solid electrolytes include Li7PS6. Conversely, examples of compositions that are halogen-containing second solid electrolytes include Li... 7-α PS 6-α X α X is at least one halogen, and α satisfies 0 < α < 2. α can be 0.1 or more, 0.5 or more, or 0.7 or more. On the other hand, α can be 1.8 or less, 1.5 or less, 1.2 or less, or 1.0 or less.

[0054] 3. Composite materials

[0055] The composite material disclosed herein may contain electrode active materials or may not contain electrode active materials. That is, the composite material disclosed herein may be used for electrode layers (positive electrode active material layer and negative electrode active material layer) or for electrolyte layers.

[0056] The electrode active material can be either a negative electrode active material or a positive electrode active material.

[0057] Examples of anode active materials include Si-based, carbon-based, and Li-based active materials. Si-based active materials are those containing the element Si. Examples of Si-based active materials include elemental Si, Si alloys, and Si oxides. Si alloys preferably contain Si as a main component. The proportion of Si in the Si alloy is, for example, 50 mol% or more, 70 mol% or more, or 90 mol% or more. On the other hand, the proportion of Si in the Si alloy is, for example, 99 mol% or less. Examples of Si alloys include Si-Al alloys, Si-Sn alloys, Si-In alloys, Si-Ag alloys, Si-Pb alloys, Si-Sb alloys, Si-Bi alloys, Si-Mg alloys, Si-Ca alloys, Si-Ge alloys, and Si-Pb alloys. Si alloys can be two-component alloys or multi-component alloys with three or more components. Examples of Si oxides include SiO.

[0058] Furthermore, Si-based active materials can possess diamond-type crystal phases, inclusion compound type I crystal phases, and inclusion compound type II crystal phases. In inclusion compound type I or II crystal phases, multiple Si elements are used to form polyhedra (cages) containing pentagons or hexagons. These polyhedra have internal spaces capable of containing metal ions such as Li ions, thus suppressing volume changes caused by charging and discharging.

[0059] Furthermore, Si-based active materials can contain voids within the primary particles. These voids can be used to suppress volume changes in the active material and inhibit cracking of the electrode layer (negative electrode active material layer). There are no particular limitations on the porosity; for example, it can be between 4% and 40%. The presence of voids and porosity in the primary particles can be confirmed by observation using SEM (scanning electron microscopy).

[0060] Carbon-based active materials are inorganic active materials containing the element carbon (C), such as graphite, hard carbon, and soft carbon. Li-based active materials are active materials containing the element lithium (Li), such as elemental lithium and Li alloys.

[0061] Examples of positive electrode active materials include oxide active materials. Examples of oxide active materials include LiCoO2, LiMnO2, LiNiO2, LiVO2, and LiNi. 1 / 3 Co 1 / 3 Mn 1 / 3 O2 and other layered active substances in rock salt; LiMn2O4, Li4Ti5O 12 Li(Ni) 0.5 Mn1.5 Spinel-type active substances such as O4; olivine-type active substances such as LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4.

[0062] A coating containing a Li-ion-conducting oxide can be formed on the surface of the oxide active material. This is because it can suppress the reaction between the oxide active material and the solid electrolyte (especially a sulfide solid electrolyte). Examples of Li-ion-conducting oxides include LiNbO3. The coating thickness is, for example, 1 nm or more and 30 nm or less. Furthermore, Li₂S can also be used as a positive electrode active material, for example.

[0063] The shape of electrode active materials can be exemplified by, for example, particulate matter. The average particle size (D) of the electrode active material... 50 For example, particles larger than 10 nm and smaller than 50 μm. Average particle size (D) 50 As described above. When the composite material contains electrode active material, the proportion of electrode active material in the composite material is, for example, 50% by weight or more and 90% by weight or less.

[0064] In addition, the composite material in this disclosure may contain at least one of a conductive additive and an adhesive as needed.

[0065] Examples of conductive additives include carbon materials, metal particles, and conductive polymers. Examples of carbon materials include particulate carbon materials such as acetylene black (AB) and Ketjen black (KB); and fibrous carbon materials such as carbon fibers, carbon nanotubes (CNTs), and carbon nanofibers (CNFs). The proportion of the conductive additive in the composite is, for example, 0.01% by weight or more and 10% by weight or less.

[0066] Examples of adhesives include rubber-based adhesives such as butadiene rubber (BR), acrylate butadiene rubber (ABR), and styrene-butadiene rubber (SBR); and fluorinated adhesives such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). The proportion of adhesive in the composite material is, for example, 0.01% by weight or more and 5% by weight or less.

[0067] B. Battery

[0068] Figure 1 A schematic cross-sectional view of the battery in this disclosure is shown as an example. Figure 1The battery 10 shown includes: a positive electrode active material layer 1, a negative electrode active material layer 2, and an electrolyte layer 3 disposed between the positive electrode active material layer 1 and the negative electrode active material layer 2. Furthermore, the battery 10 includes: a positive electrode current collector 4 for collecting electrons from the positive electrode active material layer 1, and a negative electrode current collector 5 for collecting electrons from the negative electrode active material layer 2. Specifically, in the battery 10 of this disclosure, at least one of the positive electrode active material layer 1, the negative electrode active material layer 2, and the electrolyte layer 3 contains the aforementioned composite material.

[0069] 1. Positive electrode active material layer and negative electrode active material layer

[0070] The positive electrode active material layer is a layer containing at least a positive electrode active material, preferably containing the aforementioned composite material. For the composite material, the same applies as described in "A. Composite Material". There is no particular limitation on the thickness of the positive electrode active material layer; for example, it may be 0.1 μm or more and 1000 μm or less.

[0071] The negative electrode active material layer is a layer containing at least a negative electrode active material, preferably containing the aforementioned composite material. For the composite material, the same applies as described in "A. Composite Material". There is no particular limitation on the thickness of the negative electrode active material layer; for example, it may be 0.1 μm or more and 1000 μm or less.

[0072] 2. Electrolyte layer

[0073] The electrolyte layer is a layer disposed between the aforementioned positive electrode active material layer and the aforementioned negative electrode active material layer, and is a layer containing at least an electrolyte. Furthermore, the electrolyte layer preferably contains the aforementioned composite material. The composite material is the same as described in "A. Composite Material".

[0074] Here, generally speaking, the electrolyte layer containing a solid electrolyte is referred to as a solid electrolyte layer, and the battery having a solid electrolyte layer is referred to as a solid-state battery. It should be noted that a solid-state battery can be a semi-solid-state battery or a fully solid-state battery. When the solid electrolyte layer in a solid-state battery contains only an inorganic solid electrolyte as the electrolyte, the aforementioned solid-state battery is called a fully solid-state battery.

[0075] As solid electrolytes, the first and second solid electrolytes mentioned above can be listed. In addition, as solid electrolytes, inorganic solid electrolytes other than the first and second solid electrolytes, such as sulfide solid electrolytes, oxide solid electrolytes, nitride solid electrolytes, halide solid electrolytes, and complex hydrides, can be listed. Oxide solid electrolytes, nitride solid electrolytes, and halide solid electrolytes typically contain oxygen (O), nitrogen (N), and halogen (X) as the main anionic elements, respectively.

[0076] In addition, as solid electrolytes, organic solid electrolytes such as polymer electrolytes and gel electrolytes can also be listed.

[0077] On the other hand, the electrolyte layer may contain an electrolyte as the electrolyte. Examples of electrolytes that are conventionally known and used in batteries include those containing lithium salts such as LiPF6 and non-aqueous solvents such as ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC). When an electrolyte is used as the electrolyte, the electrolyte layer may be a layer in which the electrolyte is impregnated within a separator. The separator (separator) may be a conventionally known component.

[0078] There are no particular limitations on the thickness of the electrolyte layer, for example, it can be above 0.1 μm and below 1000 μm.

[0079] 3. Other components

[0080] The battery disclosed herein typically has a positive current collector and a negative current collector. Examples of materials used for the positive current collector include SUS, aluminum, nickel, iron, titanium, and carbon. On the other hand, examples of materials used for the negative current collector include SUS, copper, nickel, and carbon.

[0081] Furthermore, the battery of this disclosure may include an outer packaging body that houses the aforementioned components. Examples of such outer packaging bodies include laminated outer packaging bodies and shell-type outer packaging bodies. Additionally, the battery of this disclosure may include a constraint clamp that applies a constraint pressure in the thickness direction to the aforementioned components. Known clamps can be used as constraint clamps. The constraint pressure may be, for example, 0.1 MPa or more and 50 MPa or less, or 1 MPa or more and 20 MPa or less.

[0082] 4. Battery

[0083] The battery disclosed herein can be a liquid battery with an electrolyte layer containing an electrolyte, or a solid battery with an electrolyte layer containing a solid electrolyte. Furthermore, as mentioned above, the solid battery can be a semi-solid battery or a fully solid battery.

[0084] There is no particular limitation on the type of battery used in this disclosure; typically, it is a lithium-ion battery. Furthermore, the battery in this disclosure can be a primary battery or a secondary battery, with a secondary battery being preferred. This is because it can be repeatedly charged and discharged, and can be used, for example, as a vehicle battery.

[0085] The application of the battery in this disclosure is not particularly limited, and examples include power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs), gasoline vehicles, and diesel vehicles. It is particularly preferred for use as a power source for driving hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or battery electric vehicles (BEVs). Furthermore, the battery in this disclosure can be used as a power source for mobile bodies other than vehicles (e.g., railways, ships, aircraft), and as a power source for electrical appliances such as information processing devices.

[0086] It should be noted that this disclosure is not limited to the embodiments described above. The embodiments described above are illustrative examples, and technical solutions with substantially the same structure and achieving the same effect as those described in the patent claims of this disclosure are all included within the technical scope of this disclosure.

[0087] Example

[0088] [Example 1]

[0089] First, the first solid electrolyte (BH4 sulfosilver germanium ore) was prepared as described below.

[0090] Li₂S (11.4828 g) and P₂S₅ (18.5172 g) were weighed and ball-milled in heptane using 500 ml of ZrO₂ balls (5 mm in diameter). This yielded Li₃PS₄. Li₃PS₄ and LiBH₄ were weighed to achieve a 1:3 molar ratio and ball-milled in heptane using 500 ml of ZrO₂ balls (5 mm in diameter). This yielded the first solid electrolyte (BH₄ sulforaph-germanium ore). For the obtained first solid electrolyte, wet particle size adjustment was performed using a ball mill. Balls with a diameter of 0.3 mm were used, and a mixture of heptane and dibutyl ether was used as the solvent. Then, calcination was carried out at 150°C for 3 hours under an inactive atmosphere.

[0091] Secondly, as described below, a second solid electrolyte (halogenated sulfide germanium ore) was prepared.

[0092] Li₂S (0.2892 g), P₂S₅ (0.3682 g), LiCl (0.1124 g), and LiBr (0.2302 g) were mixed and ball-milled using 45 ml of ZrO₂ balls (5 mm in diameter). The resulting mixed powder was calcined at 500 °C for 4 hours in an inactive atmosphere. This yielded a second solid electrolyte (halogenated silver-germanium sulfide). The obtained second solid electrolyte was then pulverized using a mortar and pestle, followed by ball milling for wet particle size adjustment. Note that 1 mm diameter balls were used in the ball milling, and a mixture of heptane and butyl butyrate was used as the solvent.

[0093] The first and second solid electrolytes were weighed such that the proportion of the first solid electrolyte relative to the total of the first and second solid electrolytes was 10.0% by weight, and then mixed in a mortar. This produced a composite containing the first and second solid electrolytes. This composite was used as a sample for evaluation, as described later. It should be noted that, although not specifically illustrated, XRD measurements were performed on the first and second solid electrolytes, and the results confirmed that the peak of the steric sulfide-germanium type crystal phase was the dominant peak.

[0094] [Examples 2-5]

[0095] Except for altering the proportion of the first solid electrolyte as described in Table 1, the composite material was prepared in the same manner as in Example 1. These composite materials were used as samples and evaluated as described later.

[0096] [Compare Example 1 and Compare Example 2]

[0097] The first or second solid electrolyte described above was used as a sample and evaluated as described later.

[0098] [evaluate]

[0099] <Determination of Ionic Conductivity>

[0100] For the above samples, compacts (powder compacts) were prepared by pressing them using a macole cylinder at a pressure of 6 tons. Impedance measurements were performed on the compacts at 25°C to determine the resistance value, and the ionic conductivity was calculated from the shape factor. The results are shown in Table 1 and... Figure 2 .

[0101] Table 1

[0102] The proportion of the first solid electrolyte (wt%) Ionic conductivity (mS / cm) Comparative Example 1 0.0 5.46 Example 1 10.0 6.31 Example 2 20.0 7.39 Example 3 33.3 7.04 Example 4 50.0 7.07 Example 5 96.7 5.86 Comparative Example 2 100.0 5.78

[0103] As shown in Table 1 and Figure 2 As shown, the composite material of this disclosure exhibits good ionic conductivity. This implies that by using the composite material of this disclosure in the battery, the ionic conductivity becomes good in the electrode layer and electrolyte layer.

Claims

1. The composite material is a composite material containing a first solid electrolyte and a second solid electrolyte, wherein the first solid electrolyte and the second solid electrolyte contain Li, P and S and have a sulfide-germanium ore-type crystal structure, wherein the first solid electrolyte contains an anionic component containing B, and the second solid electrolyte does not contain an anionic component containing B.

2. The composite material according to claim 1, wherein, The anionic component containing B is BH4. - .

3. The composite material according to claim 1, wherein, The proportion of the first solid electrolyte is 7.0% by weight or more and 75.0% by weight or less relative to the total of the first solid electrolyte and the second solid electrolyte.

4. The composite material according to claim 1, wherein, The proportion of the first solid electrolyte is 15.0% by weight or more and 60.0% by weight or less relative to the total of the first solid electrolyte and the second solid electrolyte.

5. The composite material according to claim 1, wherein, The second solid electrolyte contains halogens as anionic components.

6. The composite material according to claim 5, wherein, The second solid electrolyte contains at least one of Cl and Br as the halogen.

7. The composite material according to claim 1, wherein, The composite material contains electrode active substances.

8. The composite material according to claim 7, wherein, The electrode active material contains a negative electrode active material.

9. The composite material according to claim 7, wherein, The electrode active material contains a positive electrode active material.

10. A battery having a positive electrode active material layer, a negative electrode active material layer, and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein at least one of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer contains a composite material according to any one of claims 1 to 9.

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