Electrode active material layer for solid state battery

Abstract

To provide an electrode active material layer for a solid state battery that can reduce resistance of the solid state battery.SOLUTION: An electrode active material layer for a solid state battery comprises: a halide solid electrolyte; and a metal that reacts with the halide solid electrolyte to increase an electron conductivity of the halide solid electrolyte. The content of the metal may be 5 ppm by volume to 10,000 ppm by volume with respect to the electrode active material layer for the solid state battery. A positive electrode active material layer, a solid state electrolyte layer, and a negative electrode active material layer are provided in this order, and the positive electrode active material layer and / or the negative electrode active material layer is the above-described electrode active material layer for the solid state battery.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an electrode active material layer for a solid state battery. [Background technology]

[0002] Solid-state batteries are secondary batteries that contain a solid electrolyte as an electrolyte, and have attracted attention because they are safer than liquid-based batteries that use an electrolytic solution as an electrolyte. Various developments have been made on solid-state batteries. For example, if a metal is contained in the electrode active material layer, there is a risk of short-circuiting or the like occurring in the battery. Therefore, the following method for manufacturing a sulfide solid-state battery is known, which prevents such batteries from leaking.

[0003] Patent Document 1 discloses a method for manufacturing an all-solid-state sulfide battery, in which an all-solid-state sulfide battery having a positive electrode layer, a negative electrode layer, and a sulfide solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer is aged before initial charging. The method for manufacturing a solid-state sulfide battery disclosed in Patent Document 1 is said to be capable of preventing the release of defective products. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-191183 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide an electrode active material layer for a solid state battery that can reduce the resistance of the solid state battery. [Means for solving the problem]

[0006] The present disclosure achieves the above object by the following means.

[0007] <Aspect 1> halide solid electrolytes, and a metal that reacts with the halide solid electrolyte to increase the electronic conductivity of the halide solid electrolyte; An electrode active material layer for a solid battery comprising: <Aspect 2> 2. The electrode active material layer for a solid battery according to aspect 1, wherein the content of the metal is 5 ppm by volume to 10,000 ppm by volume with respect to the electrode active material layer for a solid battery. <Aspect 3> 3. The electrode active material layer for a solid battery according to aspect 1 or 2, wherein the metal is at least one metal selected from copper, silver, nickel, iron, tin, aluminum, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum, and alloys thereof. <Aspect 4> 4. The electrode active material layer for a solid battery according to any one of Aspects 1 to 3, wherein the halide solid electrolyte is a compound containing elemental bromine and elemental chlorine. <Aspect 5> 5. The electrode active material layer for a solid battery according to any one of Aspects 1 to 4, wherein the halide solid electrolyte is a compound containing elemental yttrium. <Aspect 6> the metal is copper, the content of the metal is 20 ppm by volume to 100 ppm by volume with respect to the electrode active material layer for a solid battery; 6. An electrode active material layer for a solid battery according to any one of aspects 1 to 5. <Aspect 7> A cathode active material layer, a solid electrolyte layer, and an anode active material layer are provided in this order; and The positive electrode active material layer and / or the negative electrode active material layer is the electrode active material layer for a solid battery according to any one of Aspects 1 to 6. solid state battery. [Effects of the Invention]

[0008] The electrode active material layer for a solid state battery according to the present disclosure can reduce the resistance of the solid state battery. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a solid state battery according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present disclosure.

[0011] In the context of the present disclosure, a "solid-state battery" refers to a battery that uses at least a solid electrolyte as the electrolyte, and thus a solid-state battery may use a combination of a solid electrolyte and a liquid electrolyte as the electrolyte. Also, in the context of the present disclosure, a solid-state battery may be an all-solid-state battery, i.e., a battery that uses only a solid electrolyte as the electrolyte.

[0012] In the present disclosure, a "composite" refers to a composition that can constitute an electrode active material layer, etc., either as it is or by further containing other components. Also, in the present disclosure, a "composite slurry" refers to a slurry that contains a dispersion medium in addition to a "composite" and can be applied and dried to form a positive electrode active material layer, etc.

[0013] 《Electrode active material layer for solid battery》 The electrode active material layer for a solid battery according to the present disclosure comprises: halide solid electrolytes, and a metal that reacts with the halide solid electrolyte to increase the electronic conductivity of the halide solid electrolyte; Contains:

[0014] The electrode active material layer for a solid state battery according to the present disclosure can reduce the resistance of the solid state battery.

[0015] In general, halide solid electrolytes are known to have low electronic conductivity. It is also known that electrode active material layers contain as little metal as possible to prevent short-circuiting of the battery due to the metal. The present inventors have discovered that the resistance of a solid-state battery can be reduced by using a halide solid electrolyte and an electrode active material layer for a solid-state battery containing a predetermined metal.

[0016] Without being limited by theory, it is speculated that in an electrode active material layer containing a halide solid electrolyte and a predetermined metal, the halide solid electrolyte and the predetermined metal react to form a metal halide, thereby increasing the electronic conductivity of the halide solid electrolyte.

[0017] Furthermore, it is presumed that the increased electronic conductivity of the halide solid electrolyte optimizes the electronic conduction path in the electrode active material layer, reducing the electrode reaction resistance, and thereby reducing the resistance of the solid-state battery.

[0018] In the present disclosure, the electrode active material layer contains at least a halide solid electrolyte, the above-mentioned metal, and an electrode active material, and may further contain, optionally, other solid electrolytes, a conductive additive, a binder, etc. The electrode active material layer may also contain various other additives.

[0019] The electrode active material layer for a solid battery of the present disclosure may be a positive electrode active material layer or a negative electrode active material layer.

[0020] The contents of the electrode active material, halide solid electrolyte, metal, solid electrolyte, conductive additive, binder, etc. in the electrode active material layer may be appropriately determined depending on the target battery performance. For example, when the entire electrode active material layer (total solid content) is taken as 100 mass%, the content of the electrode active material may be 40 mass% or more, 50 mass% or more, or 60 mass% or more, or 100 mass% or less, or 90 mass% or less.

[0021] <Halide solid electrolyte> The halide solid electrolyte may be a compound containing lithium, M, and X. Here, M is at least one element selected from the group consisting of metal elements other than lithium and metalloid elements, and X is at least one element selected from the group consisting of fluorine, chlorine, bromine, and iodine.

[0022] The halide solid electrolyte is preferably a compound containing bromine and chlorine, although it is not particularly limited thereto. The halide solid electrolyte is preferably a compound containing yttrium, although it is not particularly limited thereto. Examples of the halide solid electrolyte include Li3YX6, LiMgX4, Li2FeX4, LiAlX4, and Li3AlX6, and more specifically, Li3YBr2Cl4, Li3YBr3Cl3, and Li3YCl6, but are not limited thereto. Here, the X element is, as described above, at least one element selected from the group consisting of fluorine, chlorine, bromine, and iodine.

[0023] The halide solid electrolyte is not particularly limited, but can be produced by mixing raw material powders, pulverizing them, and sintering them in a vacuum or in an inert atmosphere depending on the desired composition.

[0024] <metal> The electrode active material layer for a solid battery of the present disclosure contains a metal that reacts with a halide solid electrolyte to increase the electronic conductivity of the halide solid electrolyte.

[0025] A method for verifying whether a metal is a metal (specific metal) that reacts with a halide solid electrolyte to increase electronic conductivity will be described.

[0026] First, a metal to be verified and a halide solid electrolyte are mixed and heat-treated to obtain a sample. At this time, the mixing conditions and heat-treatment conditions are set as follows. Mixing conditions: The halide solid electrolyte and the target metal (using metal powder) are mixed so that the metal powder concentration is 5% by volume. Specifically, 1 g of the halide solid electrolyte is weighed out so that the metal powder content is 5% by volume, and dry-mixed in a mortar for 5 minutes to obtain a mixed powder. Heat treatment conditions: The Swagelok cell described below is placed in a thermostatic chamber set at 150°C and heat treated for 7 days. After 7 days, it is removed from the thermostatic chamber and cooled to 25°C, after which the post-heat treatment electronic conductivity is measured.

[0027] Next, the electronic conductivity of each sample before and after the heat treatment is measured by the following method: 200 mg of the sample is weighed and placed in a Swagelok cylinder and heated to 1 ton / cm 2 The pellet is pressed with a pressure of 0.01 V. Both ends of the resulting pellet are clamped with stainless steel pins and bolted to apply a confining pressure to the pellet. The pellet is sealed in a Swagelok cylinder, which is called a Swagelok cell. For the heat-treated sample, the Swagelok cell is used for heat treatment under the above heat treatment conditions. The resulting sample is kept at 25°C, and the electronic conductivity is calculated using the DC polarization method. Measurements are made using Solartron's Celltest and Solartron 1260. Voltages of 0.1 V, 0.2 V, and 0.3 V are applied for 30 seconds, and the amount of current passing through is measured. Resistance is calculated from the relationship between the applied voltage and the amount of current passing through, and electronic conductivity is then calculated.

[0028] The electronic conductivity of the sample is then compared before and after the heat treatment. The increase in electronic conductivity is calculated by dividing the electronic conductivity after the heat treatment by the electronic conductivity before the heat treatment. If the increase in electronic conductivity is 2.17 or higher, the sample is determined to be a metal (specific metal) that reacts with the halide solid electrolyte to increase electronic conductivity.

[0029] Examples of the metal (specific metal) include, but are not limited to, at least one metal selected from copper, silver, nickel, iron, tin, aluminum, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum, and alloys thereof. Among these, the metal (specific metal) is not particularly limited, but copper is preferred from the viewpoint of reducing the resistance of the solid-state battery.

[0030] The shape of the above metal (specific metal) is not particularly limited, and may be in the form of particles or non-particles.

[0031] The content of the metal (specific metal) is not particularly limited, but is preferably 5 to 10,000 ppm by volume from the viewpoint of reducing the resistance of the solid-state battery, and more preferably 20 to 100 ppm by volume from the viewpoint of reducing the resistance of the solid-state battery and suppressing self-discharge. The content of the metal (specific metal) is not particularly limited, but may be 5 ppm by volume or more, 10 ppm by volume or more, 20 ppm by volume or more, or 50 ppm by volume or more, or may be 10,000 ppm by volume or less, 1,000 ppm by volume or less, 500 ppm by volume or less, 200 ppm by volume or less, or 100 ppm by volume or less. Here, the content of the metal is the ratio of the volume of the metal to the volume of the electrode active material layer for a solid-state battery.

[0032] The content (volume ratio) of the above metal (specific metal) can be measured by observing a cross section of the electrode active material layer for a solid state battery with an EDS-equipped scanning electron microscope (SEM-EDS, magnification 30,000 times) and performing elemental analysis with energy dispersive spectroscopy (EDS).

[0033] <Electrode active material> The electrode active material layer for a solid battery according to the present disclosure includes an electrode active material. When the electrode active material layer is a positive electrode active material layer, the electrode active material is a positive electrode active material, and when the electrode active material layer is a negative electrode active material layer, the electrode active material is a negative electrode active material.

[0034] (Cathode active material) The material of the positive electrode active material is not particularly limited as long as it can absorb and release lithium ions. Examples of the positive electrode active material include lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), lithium manganese oxide (LiMnO), and nickel-cobalt-manganese oxide (NCM:LiCO 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), lithium nickel-cobalt-aluminate (LiNi 0.8 (CoAl) 0.2 O2), etc., but are not limited to these.

[0035] The positive electrode active material may have a coating layer, although it is not particularly limited. The coating layer is a layer containing a substance that has lithium ion conductivity, low reactivity with the positive electrode active material and the solid electrolyte, and can maintain the shape of the coating layer without flowing even when in contact with the active material and the solid electrolyte. Specific examples of materials that constitute the coating layer include LiNbO3 and Li4Ti5O 12 , Li3PO4, etc., but are not limited to these.

[0036] The shape of the positive electrode active material is not particularly limited as long as it is a general shape for a positive electrode active material of a solid-state battery. The positive electrode active material may be, for example, in the form of particles. The positive electrode active material may be in the form of primary particles or secondary particles formed by agglomeration of a plurality of primary particles. The average particle diameter D of the positive electrode active material 50 The average particle size D may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. 50 is the particle size (median size) at 50% cumulative value in the volume-based particle size distribution determined by laser diffraction / scattering method.

[0037] (Negative electrode active material) As the negative electrode active material, various materials can be used that have a potential (charge / discharge potential) at which they absorb and release lithium ions that is lower than that of the positive electrode active material. The material for the negative electrode active material is not particularly limited, and may be metallic lithium or a material capable of absorbing and releasing metal ions such as lithium ions. Examples of materials capable of absorbing and releasing metal ions such as lithium ions include alloy-based negative electrode active materials, carbon materials, and lithium titanate (Li4Ti5O 12 ) and the like can be mentioned, but are not limited to these.

[0038] The alloy-based negative electrode active material is not particularly limited, and examples thereof include Si alloy-based negative electrode active materials and Sn alloy-based negative electrode active materials. Examples of Si alloy-based negative electrode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, and solid solutions thereof. The Si alloy-based negative electrode active material may contain metal elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti. Examples of Sn alloy-based negative electrode active materials include tin, tin oxide, tin nitride, and solid solutions thereof. The Sn alloy-based negative electrode active material may contain metal elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, and Si.

[0039] The carbon material is not particularly limited, and examples thereof include hard carbon, soft carbon, graphite, and the like.

[0040] The shape of the negative electrode active material is not particularly limited, and may be any shape commonly used for negative electrode active materials in solid-state batteries. The negative electrode active material may be, for example, in the form of particles or a sheet.

[0041] <Optional ingredients - other solid electrolytes> The material of the other solid electrolyte is not particularly limited, and may be, for example, a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte.

[0042] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, and argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include Li2S-P2S5-based (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2(Li 13 GeP3S 16 , Li 10 GeP2S 12 ), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x etc.; or combinations thereof, but are not limited to these.

[0043] An example of an oxide solid electrolyte is Li7La3Zr2O 12 , Li 7-x La3Zr 1-x Nb x O 12 , Li 7-3x La3Zr2Al x O 12 , Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+x Al x Ge 2-x (PO4)3, Li3PO4, or Li 3+x PO 4-x N x (LiPON), etc.; or combinations thereof.

[0044] The sulfide solid electrolyte and the oxide solid electrolyte may be glass or crystallized glass (glass ceramics).

[0045] Examples of polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0046] <Optional ingredient - conductive additive> The conductive additive is not particularly limited. The conductive additive may be, for example, vapor grown carbon fiber (VGCF), acetylene black (AB), ketjen black (KB), carbon nanotube (CNT), carbon nanofiber (CNF), conductive carbon, etc., but is not limited thereto. The conductive additive may be, for example, particulate or fibrous, and its size is not particularly limited. The conductive additive is not particularly limited, but one type may be used alone, or two or more types may be used in combination.

[0047] <Optional Component - Binder> The binder is not particularly limited. The binder may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), or other materials, but is not limited to these. The binder is not particularly limited, and one type may be used alone, or two or more types may be used in combination.

[0048] The shape of the electrode active material layer is not particularly limited, and may be, for example, a substantially flat sheet-like electrode active material layer. The thickness of the electrode active material layer is not particularly limited, and may be, for example, 0.1 μm or more, 1 μm or more, or 10 μm or more, and may be 2 mm or less, 1 mm or less, or 500 μm or less.

[0049] The electrode active material layer can be produced by applying a known method. For example, the electrode active material layer can be easily formed by dry or wet molding an electrode mixture containing the above-mentioned various components. The electrode active material layer may be molded together with the positive electrode current collector layer or the negative electrode current collector layer, or may be molded separately from the positive electrode current collector layer or the negative electrode current collector layer.

[0050] 《Solid-state battery》 The solid-state battery of the present disclosure comprises: A cathode active material layer, a solid electrolyte layer, and an anode active material layer are provided in this order; and The positive electrode active material layer and / or the negative electrode active material layer is the above-mentioned electrode active material layer for a solid battery.

[0051] The solid-state battery of the present disclosure can reduce resistance.

[0052] 1 is a schematic cross-sectional view showing one embodiment of a solid-state battery according to the present disclosure, but is not limited to this example. The solid-state battery 100 includes a positive electrode active material layer 110, a solid electrolyte layer 120, and a negative electrode active material layer 130, in this order.

[0053] The solid state battery of the present disclosure has at least a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material, and may further include an optional positive electrode current collector layer and a negative electrode current collector layer.

[0054] In the solid-state battery of the present disclosure, the positive electrode active material layer and / or the negative electrode active material layer is the electrode active material for solid-state batteries of the present disclosure. For the electrode active material layer for solid-state batteries as the positive electrode active material layer and / or the negative electrode active material layer, reference can be made to the above description of "Electrode active material layer for solid-state batteries".

[0055] <Positive electrode current collector layer> The material used for the positive electrode current collector layer is not particularly limited, and any material commonly used for positive electrode current collectors in solid-state batteries can be appropriately used. Examples of materials used for the positive electrode current collector layer include, but are not limited to, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, and stainless steel. The positive electrode current collector layer may have a coating layer on its surface for purposes such as adjusting resistance. The positive electrode current collector layer may also be a metal foil or a substrate on which the above metals are plated or vapor-deposited.

[0056] The shape of the positive electrode current collector layer is not particularly limited, but examples thereof include foil, plate, and mesh. Among these, foil is preferred. The thickness of the positive electrode current collector layer is not particularly limited, but may be 0.1 μm or more, or 1 μm or more, or 1 mm or less, or 100 μm or less.

[0057] <Solid electrolyte layer> The solid electrolyte layer contains at least a solid electrolyte, and may contain a conductive additive, a binder, etc. as necessary. For the solid electrolyte, the conductive additive, and the binder, please refer to the description in the above "<Electrode active material layer for solid battery>" section.

[0058] The thickness of the solid electrolyte layer is not particularly limited, but may be, for example, 0.1 μm or more, 1 μm or more, or 10 μm or more, and may be 2 mm or less, 1 mm or less, or 500 μm or less.

[0059] The solid electrolyte layer can be easily formed, for example, by dry or wet molding a solid electrolyte mixture containing the above-mentioned solid electrolyte and a binder.

[0060] <Negative electrode current collector layer> The material used for the negative electrode current collector layer is not particularly limited, and any material commonly used for negative electrode current collectors in solid-state batteries can be appropriately used. Examples of materials used for the negative electrode current collector layer include, but are not limited to, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, and carbon sheet. The negative electrode current collector layer may have a coating layer on its surface for the purpose of adjusting resistance, etc.

[0061] The shape of the negative electrode current collector layer is not particularly limited, but examples thereof include foil, plate, and mesh. Of these, foil is preferred. The thickness of the negative electrode current collector layer is not particularly limited, but may be 0.1 μm or more, or 1 μm or more, or 1 mm or less, or 100 μm or less.

[0062] <<Applications of solid-state batteries>> The solid-state battery in the present disclosure may be, for example, an in-vehicle battery, or may be used as a power source for moving objects other than vehicles (for example, trains, ships, and aircraft), or may be used as a power source for electrical appliances such as information processing devices. [Example]

[0063] The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0064] Example 1 <Preparation of Positive Electrode Active Material Layer A1> LiNi surface-treated with Li-Ti-Al-F-based material as a positive electrode active material 0.8 (CoAl) 0.2 O2, Li3YBr3Cl3 as a halide solid electrolyte, copper as a metal, conductive carbon as a conductive additive, styrene-butadiene rubber (SBR) as a binder, and a solvent were mixed and dispersed using an ultrasonic homogenizer (UH-50 manufactured by SMT Corporation) to prepare a positive electrode composite slurry. The amount of copper was adjusted so that the copper content (volume ratio) relative to the positive electrode active material layer was 10 ppm by volume. Next, the positive electrode composite slurry was applied to an aluminum foil as a positive electrode current collector using a blade method with an applicator, and then dried to form a positive electrode active material layer A1 on the aluminum foil.

[0065] <Preparation of solid electrolyte layer B1> Li3YBr3Cl3 as a solid electrolyte, SBR as a binder, and a solvent were mixed and dispersed using an ultrasonic homogenizer (UH-50 manufactured by SMT Corporation) to prepare a solid electrolyte composite slurry. The solid electrolyte composite slurry was then coated onto an aluminum foil by a blade method using an applicator, and dried to form a solid electrolyte layer B1 on the aluminum foil.

[0066] <Preparation of negative electrode active material layer C0> Li4Ti5O as a negative electrode active material 12The negative electrode composite slurry was prepared by mixing the lithium ion battery (Li3YBr2Cl4) as a halide solid electrolyte, conductive carbon as a conductive additive, SBR as a binder, and a solvent, and dispersing the mixture using an ultrasonic homogenizer (UH-50 manufactured by SMT Corporation). The negative electrode composite slurry was then applied to an aluminum foil as a negative electrode current collector using a blade method with an applicator, and dried to form a negative electrode active material layer C0 on the aluminum foil. The basis weight of the negative electrode active material layer was adjusted so that the charge specific capacity of the negative electrode active material layer was 1x the charge specific capacity of the positive electrode active material layer, which was 200 mAh / g.

[0067] <Fabrication of solid-state battery D1> The solid electrolyte layer B1 was placed on the surface of the negative electrode active material layer C0 formed on aluminum foil as a negative electrode current collector, and pressed to transfer the solid electrolyte layer B1 to the surface of the negative electrode active material layer C0. The aluminum foil in contact with the solid electrolyte layer B1 was then peeled off, and the solid electrolyte layer B1 was laminated on the negative electrode active material layer C0. Next, the positive electrode active material layer A1 was placed on the surface of the solid electrolyte layer B1 laminated on the surface of the negative electrode active material layer C0, and pressed to transfer and laminate the positive electrode active material layer A1 to the surface of the solid electrolyte layer B1. The resulting laminate was roll-pressed at 175°C and 5 ton / cm to obtain a densified laminate. Here, the densified laminate was composed of aluminum foil, positive electrode active material layer A1, solid electrolyte layer B1, negative electrode active material layer C0, and aluminum foil laminated in this order. The resulting densified laminate was sealed, restrained at 5 MPa, and left to stand in an environment at 80°C for 7 days to obtain a solid battery D1.

[0068] <DC resistance of solid-state battery D1> The solid-state battery D1 was placed in a thermostatic chamber set at 25°C and connected to a charge / discharge device. The solid-state battery D1 was charged at a constant current of 0.1 C until the cell voltage reached 2.7 V, and then charged at a constant voltage of 0.01 C. The battery was then discharged at a constant current of 0.1 C until the SOC reached 40%, and then charged at a constant voltage of 0.01 C. The battery was then discharged at a constant current of 72 C for 0.1 seconds. The potential difference between the voltage before the constant-current discharge and the voltage after the 0.1-second constant-current discharge was calculated, and the potential difference was divided by the current at 72 C to calculate the DC resistance. The DC resistance of the solid-state battery D1 is shown in Table 1. Table 1 also shows the DC resistance of the solid-state battery D1 relative to that of the solid-state battery d1 (Comparative Example 1), which will be described later.

[0069] <Self-discharge amount of solid-state battery D1> The solid-state battery D1 was placed in a thermostatic chamber set at 25°C and connected to a charge / discharge device. The solid-state battery D1 was charged at a constant current up to 2.515 V, and then at a constant voltage until a current value of 0.01 C was reached. The open-circuit voltage of the solid-state battery D1 was then measured for 72 hours, and the voltage after 48 hours and after 72 hours were also measured. The difference between the voltage after 48 hours and the voltage after 72 hours was calculated, and this difference was taken as the self-discharge amount over 24 hours. The self-discharge amount of the solid-state battery D1 is shown in Table 1.

[0070] Examples 2 to 8 <Preparation of Positive Electrode Active Material Layers A2 to A8> Positive electrode active material layers A2 to A8 were produced in the same manner as in Example 1, except that the amount of copper was adjusted so that the copper content (volume ratio) relative to the positive electrode active material layer was the content shown in Table 1.

[0071] <Fabrication of Solid-State Batteries D2 to D8, and DC Resistance and Self-Discharge Amount of Solid-State Batteries D2 to D8> Except for using positive electrode active material layers A2 to A8 instead of positive electrode active material layer A1, solid batteries D2 to D8 were produced in the same manner as in Example 1. The DC resistance and self-discharge amount of solid batteries D2 to D8 were determined in the same manner as in Example 1, and the results are shown in Table 1.

[0072] Comparative Example 1 <Preparation of Positive Electrode Active Material Layer A0> A positive electrode active material layer A0 was produced in the same manner as in Example 1, except that no copper was added and the copper content (volume ratio) relative to the positive electrode active material layer was 0 ppm by volume.

[0073] <Production of solid-state battery d1, and DC resistance and self-discharge amount of solid-state battery d1> Except for using the positive electrode active material layer A0 instead of the positive electrode active material layer A1, a solid battery d1 was produced in the same manner as in Example 1. The DC resistance and self-discharge amount of the solid battery d1 were determined in the same manner as in Example 1, and the results are shown in Table 1.

[0074] [Table 1]

[0075] In Examples 1 to 8, when copper-containing positive electrode active material layers A1 to A8 were used in the solid state batteries, the DC resistance of the solid state batteries was reduced compared to when copper-free positive electrode active material layer A0 was used as in Comparative Example 1. Furthermore, the lower the copper content in the positive electrode active material, the smaller the self-discharge amount.

[0076] In the positive electrode active material layers A1 to A8 of Examples 1 to 8, it is presumed that the halide solid electrolyte reacted with copper to form copper halide, the electronic conductivity of the halide solid electrolyte increased, the electronic conduction path of the positive electrode active material layer was optimized, and the electrode reaction resistance of the positive electrode active material layer was reduced, thereby reducing the resistance of the solid battery.

[0077] Examples 9 to 14 <Preparation of Negative Electrode Active Material Layers C1 to C6> Li4Ti5O as a negative electrode active material 12The negative electrode composite slurry was prepared by mixing Li3YBr3Cl3 as a halide solid electrolyte, copper as a metal, conductive carbon as a conductive additive, SBR as a binder, and a solvent, and dispersing the mixture using an ultrasonic homogenizer (UH-50 manufactured by SMT Corporation). The amount of copper was adjusted so that the copper content (volume ratio) relative to the negative electrode active material layer was the content shown in Table 2. The negative electrode composite slurry was then applied to an aluminum foil negative electrode current collector using a blade method using an applicator, and dried to form negative electrode active material layers C1 to C6 on the aluminum foil. The basis weight of the negative electrode active material layer was adjusted so that the specific charge capacity of the negative electrode active material layer was 1x the specific charge capacity of the positive electrode active material layer, which was 200 mAh / g.

[0078] <Fabrication of solid-state batteries D9-14> Except for using positive electrode active material layer A0 instead of positive electrode active material layer A1 and using negative electrode active material layers C1 to C6 instead of negative electrode active material layer C0, solid batteries D9 to D14 were produced in the same manner as in Example 1. The DC resistance and self-discharge amount of solid batteries D9 to D14 were determined in the same manner as in Example 1, and the results are shown in Table 2.

[0079] [Table 2]

[0080] In Examples 9 to 14, when copper-containing negative electrode active material layers C1 to C6 were used in the solid state batteries, the DC resistance of the solid state batteries was reduced compared to when copper-free negative electrode active material layer C0 was used as in Comparative Example 1. Furthermore, the lower the copper content in the negative electrode active material, the smaller the self-discharge amount.

[0081] It is presumed that in the negative electrode active material layers C1 to C6 of Examples 9 to 14, the halide solid electrolyte reacted with copper to form copper halide, the electronic conductivity of the halide solid electrolyte increased, the electronic conduction path of the negative electrode active material layer was optimized, and the electrode reaction resistance of the negative electrode active material layer was reduced, thereby reducing the resistance of the solid battery.

[0082] Although preferred embodiments of the electrode active material layer for a solid state battery and the solid state battery of the present disclosure have been described, those skilled in the art will understand that modifications are possible without departing from the scope of the claims. [Explanation of symbols]

[0083] 100 solid state battery 110 Cathode active material layer 120 Solid electrolyte layer 130 Negative electrode active material layer

Claims

1. halide solid electrolytes, and a metal that reacts with the halide solid electrolyte to increase the electronic conductivity of the halide solid electrolyte; An electrode active material layer for a solid battery comprising:

2. 2. The electrode active material layer for a solid battery according to claim 1, wherein the content of the metal is 5 ppm by volume to 10,000 ppm by volume with respect to the electrode active material layer for a solid battery.

3. 2. The electrode active material layer for a solid battery according to claim 1, wherein the metal is at least one metal selected from copper, silver, nickel, iron, tin, aluminum, titanium, chromium, zinc, gold, magnesium, antimony, zirconium, molybdenum, and alloys thereof.

4. 2. The electrode active material layer for a solid battery according to claim 1, wherein the halide solid electrolyte is a compound containing elemental bromine and elemental chlorine.

5. 2. The electrode active material layer for a solid battery according to claim 1, wherein the halide solid electrolyte is a compound containing elemental yttrium.

6. the metal is copper, The content of the metal is 20 ppm by volume to 100 ppm by volume with respect to the electrode active material layer for a solid battery. The electrode active material layer for a solid battery according to claim 1 .

7. A cathode active material layer, a solid electrolyte layer, and an anode active material layer are provided in this order; and The positive electrode active material layer and / or the negative electrode active material layer is an electrode active material layer for a solid battery according to any one of claims 1 to 6. solid state battery.

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