Electrode active material composite particles, electrode composite material, and battery

Abstract

The electrode active material composite particles of the present disclosure comprise a porous carbon material and silicon retained within the porous carbon material. The electrode active material composite particles of the present disclosure have pores of 10 nm or less and 0.22 cc / g or more when measured by a gas adsorption method. The electrode composite of the present disclosure comprises the electrode active material composite particles of the present disclosure. The battery of the present disclosure has an electrode active material layer, and the electrode active material layer contains the electrode composite of the present disclosure.

Description

Technology Field

[0001] The present disclosure relates to electrode active material composite particles, electrode composites, and batteries. Background Technology

[0002] Japanese Patent Publication No. 2024-073597 discloses a composite comprising a porous carbon scaffold and silicon, and an electrode comprising such a composite. Japanese Patent Publication No. 2024-073597 discloses a method of embedding silicon within a porous carbon scaffold by chemical vapor deposition (CVD) technology using silane gas. The problem to be solved

[0003] Silicon electrode active materials may expand or contract during the charging and discharging of the battery. Consequently, in batteries containing silicon electrode active materials, volume changes accompanying such expansion and contraction may occur. Even in electrode active material composites containing porous carbon materials and silicon, there is room for improvement in terms of suppressing such volume changes in the battery.

[0004] The present disclosure aims to provide an electrode active material composite particle capable of suppressing volume change of a battery, an electrode composite comprising such electrode active material composite particle, and a battery comprising such electrode composite. means of solving the problem

[0005] The initiators of this case, etc., have discovered that the above problem can be solved by the following means.

[0006] <Mode 1>

[0007] porous carbon materials, and

[0008] Silicon retained within the above porous carbon material

[0009] Includes, and also

[0010] Having pores of 10 nm or less and 0.22 cc / g or more when measured by gas adsorption method,

[0011] Electrode active material composite particle.

[0012] <Mode 2>

[0013] Electrode active material composite particle described in Embodiment 1, having pores of 2 nm or less and 0.15 cc / g or more when measured by gas adsorption method.

[0014] <Mode 3>

[0015] When measured by the gas adsorption method,

[0016] The above-mentioned pores of 10 nm or less have a g of 0.50 cc / g or more and 0.60 cc / g or less, and also

[0017] Electrode active material composite particle described in Embodiment 1 or 2, having pores of 2 nm or less and a weight of 0.25 cc / g or more and 0.35 cc / g or less.

[0018] <Mode 4>

[0019] An electrode composite comprising electrode active material composite particles described in any one of embodiments 1 to 3.

[0020] <Mode 5>

[0021] It has an electrode active material layer, and also

[0022] The above electrode active material layer contains the electrode composite material described in Embodiment 4,

[0023] battery. Effects of the invention

[0024] According to the present disclosure, electrode active material composite particles capable of suppressing volume change of a battery, an electrode composite material comprising such electrode active material composite particles, and a battery comprising such electrode composite material can be provided. Brief explanation of the drawing

[0025] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, and like reference numerals denote like elements. Figure 1 is a graph showing the cumulative pore distribution of an example, a comparative example, and a porous carbon material. Figure 2 is a graph showing the fine pore distribution of the example, comparative example, and porous carbon material. Specific details for implementing the invention

[0026] The embodiments of the present disclosure are described in detail below. Furthermore, the present disclosure is not limited to the embodiments below and may be implemented with various modifications within the scope of the disclosed purpose.

[0027] Electrode active material composite particles

[0028] The electrode active material composite particles of the present disclosure comprise a porous carbon material and silicon retained within the porous carbon material. The electrode active material composite particles of the present disclosure have pores of 10 nm or less at a rate of 0.22 cc / g or more when measured by a gas adsorption method.

[0029] The present disclosure parties have discovered that an electrode active material composite particle comprising a porous carbon material and silicon retained within the porous carbon material can suppress volume changes of the battery accompanying expansion and contraction of silicon during charging and discharging by having a predetermined amount or more of pores with a relatively small pore diameter.

[0030] For this reason, although it is not intended to be bound by any theory, it is estimated as follows. That is, for example, when manufacturing a battery, particularly a solid-state battery, there are cases where the electrode active material layer is pressed. It is thought that pores with a relatively small diameter are difficult to crush by the press. The electrode active material composite particles of the present disclosure have a predetermined amount of such pores, and accordingly, it is thought that the effects of the expansion and contraction mentioned above can be mitigated, and thus the volume change of the battery can be suppressed.

[0031] The “electrode active material” may be a “positive electrode active material” or a “negative electrode active material,” and especially may be a “negative electrode active material.”

[0032] Hereinafter, each element constituting the electrode active material composite particle of the present disclosure will be described.

[0033] porous carbon material

[0034] The electrode active material composite particle of the present disclosure comprises a porous carbon material. The porous carbon material retains silicon within its pores.

[0035] The porous carbon material is not particularly limited. The porous carbon material may be, for example, activated carbon. The porous carbon material may be a material having interconnected pores. An example of such a material is the commercially available Knobel (registered trademark) MH-00.

[0036] The pore diameter and pore volume of the porous carbon material are not particularly limited. The porous carbon material may have pores of 10 nm or less when measured by gas adsorption method, 0.30 cc / g or more, 0.40 cc / g or more, 0.50 cc / g or more, 0.55 cc / g or more, or 0.60 cc / g or more, and may also have 1.00 cc / g or less, 0.90 cc / g or less, 0.80 cc / g or less, 0.75 cc / g or less, or 0.70 cc / g or less.

[0037] The maximum value of the peak in the fine pore distribution by gas adsorption of a porous carbon material may be located at 1 nm or more, 2 nm or more, 3 nm or more, or 4 nm or more, and may also be located at 10 nm or less, 7 nm or less, 5 nm or less, or 4 nm or less.

[0038] The gas adsorption method is not particularly limited; for example, after measuring the N2 adsorption isotherm, the cumulative pore distribution and the fine pore distribution may be obtained by the BJH (Barrett-Joyner-Halenda) method. In this case, the BELSORPMAXX, a specific surface area and pore distribution measuring device manufactured by Microtrax, can be used. From the cumulative pore distribution and fine pore distribution obtained in this way, the pore diameter and pore volume can be determined. The pore diameter and pore volume of the electrode active material composite particles described later can also be determined by the same method.

[0039] silicone

[0040] The electrode active material composite particle of the present disclosure comprises silicon retained within a porous carbon material. The silicon functions as an electrode active material and, accordingly, expands and contracts during the charging and discharging of the battery.

[0041] The silicon is not particularly limited and, for example, may be one produced using an alkoxysilane as a raw material by the method described below.

[0042] The shape, size, etc. of the silicon is not particularly limited as long as the silicon functions as an electrode active material.

[0043] In the electrode active material composite particles of the present disclosure, the mass ratio of silicon to the porous carbon material may be 0.1 or more and 10.0 or less. This mass ratio may be 0.1 or more, 0.3 or more, 0.5 or more, 0.7 or more, 0.9 or less, or 1.0 or more, and may be 10.0 or less, 7.0 or less, 5.0 or less, 3.0 or less, 2.0 or less, or 1.0 or less. That is, the mass ratio of silicon to the porous carbon material may be 1:1. By keeping the mass ratio of silicon to the porous carbon material within the above range, it is easy to make the relationship between the pore diameter and pore volume of the electrode active material composite particles of the present disclosure within the range of the present disclosure.

[0044] craftsmanship

[0045] The electrode active material composite particles of the present disclosure have pores of 10 nm or less and 0.22 cc / g or more when measured by gas adsorption. By doing so, the effect of expansion and contraction of silicon during charging and discharging of the battery can be mitigated, and thus, changes in the volume of the battery can be suppressed.

[0046] The electrode active material composite particles may have pores of 10 nm or less when measured by gas adsorption method, 0.25 cc / g or more, 0.30 cc / g or more, 0.35 cc / g or more, 0.40 cc / g or more, 0.45 cc / g or more, or 0.50 cc / g or more, and may also have pores of 1.00 cc / g or less, 0.90 cc / g or less, 0.80 cc / g or less, 0.75 cc / g or less, 0.70 cc / g or less, 0.65 cc / g or less, 0.60 cc / g or less, or 0.55 cc / g or less. By doing so, the volume change of the battery can be effectively suppressed.

[0047] The electrode active material composite particles of the present disclosure may have pores of 2 nm or less when measured by a gas adsorption method, 0.15 cc / g or more, 0.20 cc / g or more, or 0.25 cc / g or more, and may also have 0.45 cc / g or less, 0.40 cc / g or less, or 0.35 cc / g or less. By doing so, the volume change of the battery can be effectively suppressed.

[0048] The electrode active material composite particles of the present disclosure may have pores of 10 nm or less in an amount of 0.40 cc / g or more and 0.70 cc / g or less, 0.45 cc / g or more and 0.65 cc / g or less, or 0.50 cc / g or more and 0.60 cc / g or less, and may also have pores of 2 nm or less in an amount of 0.15 cc / g or more and 0.45 cc / g or less, 0.20 cc / g or more and 0.40 cc / g or less, or 0.25 cc / g or more and 0.35 cc / g or less. By doing so, the volume change of the battery can be effectively suppressed.

[0049] With respect to the present disclosure, “pores of 10 nm or less” and “pores of 2 nm or less” include the following:

[0050] · The pores of the porous carbon material that are not filled with silicon at all or / or sufficiently, and consequently remain

[0051] · Void formed between silicon and porous carbon material in the pores of a silicon-filled porous carbon material

[0052] · Porous silicon pores

[0053] Regarding the above “voids” and “pores of porous silicon,” although they will be described in detail later, they may appear by removing magnesium oxide that may be generated during the process of manufacturing electrode active material composite particles.

[0054] Method for manufacturing electrode active material composite particles

[0055] The electrode active material composite particles of the present disclosure can be manufactured by a method comprising the following process:

[0056] (a) Providing a composite containing silicon oxide within a porous carbon material,

[0057] (b) reducing silicon oxide in the composite with magnesium to obtain an electrode active material composite particle precursor comprising silicon and magnesium oxide within a porous carbon material, and

[0058] (c) Removing at least some magnesium oxide from the electrode active material composite particle precursor.

[0059] Provision of complex

[0060] The above method may include (a) providing a composite comprising silicon oxide within a porous carbon material. In the present disclosure, "silicon oxide" may be silicon dioxide (SiO2).

[0061] A method for providing a composite containing silicon oxide (SiO2) within a porous carbon material is not particularly limited, and, for example, a method by chemical vapor deposition (CVD) may be used. Specifically, the following method is exemplified. That is, first, a porous carbon material is introduced into the core tube of a CVD apparatus, and the inside of the core tube is heated after depressurization. Subsequently, an oxygen line is inserted into a vessel containing an alkoxysilane, and the alkoxysilane is bubbled with oxygen to introduce oxygen containing alkoxysilane vapor into the core tube. By maintaining this state, a composite containing SiO2 within a porous carbon material may be provided.

[0062] The alkoxysilane is not particularly limited and, for example, may be tetraalkoxysilane, or may be an alkoxysilane modified by a substituent other than an alkoxy group.

[0063] Tetraalkoxysilane is not particularly limited and may be, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, or a combination thereof, and in particular may be tetraethoxysilane (TEOS).

[0064] The alkoxysilane modified by a substituent other than an alkoxy group is not particularly limited. The substituent other than an alkoxy group is not particularly limited and may be, for example, a methyl group, an ethyl group, a phenyl group, a vinyl group, etc. The alkoxy group is not particularly limited and may be, for example, a methoxy group, an ethoxy group, etc. The number of substituents other than an alkoxy group and the alkoxy groups are not particularly limited.

[0065] The heating temperature is not particularly limited and, for example, may be 100°C or higher, 300°C or higher, 400°C or higher, or 500°C or higher, or may be 1000°C or lower, 800°C or lower, 600°C or lower, or 500°C or lower.

[0066] The time for maintaining the state of introducing oxygen containing alkoxysilane vapor into the core tube is not particularly limited, and for example, it may be 1 hour or more, 3 hours or more, 5 hours or more, or 6 hours or more, or 30 hours or less, 20 hours or less, 15 hours or less, 10 hours or less, 8 hours or less, or 6 hours or less.

[0067] Reduction of silicon oxide

[0068] The above method may include (b) reducing silicon oxide (SiO2) in the composite with magnesium (Mg) to obtain an electrode active material composite particle precursor containing silicon (Si) and magnesium oxide (MgO) within a porous carbon material.

[0069] Methods for reducing SiO2 to Mg are not particularly limited, and for example, a method of contacting Mg vapor with the composite can be used. Methods for generating Mg vapor are not particularly limited, and for example, a method of heating a reducing agent that serves as a source of Mg, such as a Mg alloy or metallic Mg, can be used.

[0070] The Mg alloy is not particularly limited and may be at least one selected from, for example, Mg2Si, MgCa, MgCu2, MgNi2, and MgSn.

[0071] The pressure at which SiO2 is reduced to Mg is not particularly limited. This pressure may, for example, be less than 1 atmosphere, 100 Pa or less, or 20 Pa or less. This pressure may, for example, be a Mg vapor pressure that is lower than the equilibrium pressure of a reversible decomposition reaction that decomposes Mg2Si into Mg vapor and Si.

[0072] The temperature at which SiO2 is reduced to Mg is not particularly limited and, for example, may be 500°C or higher, 600°C or higher, or 650°C or higher, or may be 900°C or lower, 800°C or lower, 700°C or lower, or 650°C or lower. By doing so, the volume of pores with a diameter of 20 nm or less in the porous silicon obtained after the process (c) described later can be increased.

[0073] The time taken to reduce SiO2 to Mg is not particularly limited and, for example, may be 1 hour or more, 3 hours or more, 5 hours or more, or 10 hours or more, or 30 hours or less, 20 hours or less, 15 hours or less, or 10 hours or less.

[0074] The amount of Mg can be an amount that generates at least 1 molar equivalent of Mg vapor with respect to the number of moles of SiO2, that is, an amount that can adequately reduce SiO2.

[0075] The mass ratio of Mg to the complex is not particularly limited as long as SiO2 can be adequately reduced. This mass ratio may, for example, be 1 or more, 2 or more, or 2.5 or more, and may also be 10 or less, 5 or less, or 2.5 or less.

[0076] The following method is exemplified as a specific method for process (b). That is, first, the complex and Mg source are introduced into the reaction vessel. Then, the reaction vessel is placed in a vacuum furnace, and while vacuuming the inside of the vacuum furnace with a rotary pump, the temperature is raised and heated.

[0077] Removal of magnesium oxide

[0078] The above method may include (c) removing at least some MgO from the electrode active material composite particle precursor. By doing so, the electrode active material composite particle is produced. Also, as MgO is removed, a void is formed between the Si in the pores of the Si-filled porous carbon material and the porous carbon material, and the silicon in the electrode active material composite particle becomes porous, thereby producing porous silicon.

[0079] Methods for removing at least some of the MgO are not particularly limited, and, for example, can be a method of treating the electrode active material composite particle precursor with acid.

[0080] A method for treating an electrode active material composite particle precursor with acid is not particularly limited, and an example is a method of mixing the electrode active material composite particle precursor with acid.

[0081] Acids are not particularly limited and include, for example, inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid.

[0082] The concentration of the acid is not specifically limited and can be appropriately set depending on the type of acid.

[0083] When MgO is removed using acid, the above method may additionally include washing the electrode active material composite particles with water, alcohol, etc., drying them, etc.

[0084] Electrode composite

[0085] The electrode composite of the present disclosure comprises electrode active material composite particles of the present disclosure. The electrode composite may optionally include a solid electrolyte, a conductivity aid, a binder, etc.

[0086] In relation to the present disclosure, "electrode composite" refers to a composition that can form an electrode active material layer as is or by additionally containing other components. Also, in relation to the present disclosure, "electrode composite slurry" refers to a slurry that includes a dispersion medium in addition to the "electrode composite" and can form an electrode active material layer by coating and drying accordingly.

[0087] With respect to the present disclosure, the “electrode composite” may be a “positive electrode composite”, a “negative electrode composite”, and especially a “negative electrode composite”.

[0088] Hereinafter, each element constituting the electrode composite of the present disclosure will be described.

[0089] Electrode active material composite particles

[0090] For electrode active material composite particles, refer to the above description.

[0091] The content of the electrode active material composite particles in the electrode composite material is not particularly limited and can be appropriately set by considering the desired battery capacity, etc.

[0092] solid electrolyte

[0093] Examples of solid electrolytes include 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. The solid electrolyte may specifically be a sulfide solid electrolyte.

[0094] For example, if the battery is a lithium-ion secondary battery, the solid electrolyte may have lithium-ion conductivity.

[0095] Examples of sulfide solid electrolytes having lithium ion conductivity include solid electrolytes containing the element Li, the element X (where X is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In), and the element S. Additionally, the sulfide solid electrolyte may further contain at least one of the element O and a halogen element. Examples of halogen elements include the element F, the element Cl, the element Br, and the element I.

[0096] As sulfide solid electrolytes, for example, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-ZmSn (where m and n are positive, and Z is any one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive, and M is any of P, Si, Ge, B, Al, Ga, or In.) can be cited.

[0097] Examples of oxide solid electrolytes having lithium ion conductivity include solid electrolytes containing the element Li, the element Y (where Y is at least one of Nb, B, Al, Si, P, Ti, Zr, Mo, W, and S), and the element O. A specific example is Li7La3Zr2O 12 , Li 7-x La3(Zr2-x Nb x )O 12 (0 ≤ x ≤ 2), Li5La3Nb2O 12 Examples include garnet-type solid electrolytes such as (Li, La)TiO3, (Li, La)NbO3, (Li, Sr)(Ta, Zr)O3, perovskite-type solid electrolytes such as Li(Al, Ti)(PO4)3, Li(Al, Ga)(PO4)3, Nasicon-type solid electrolytes such as Li3PO4, LiPON (a compound in which some of the O in Li3PO4 is substituted with N), and Li-BO-type solid electrolytes such as Li3BO3, a compound in which some of the O in Li3BO3 is substituted with C.

[0098] The content of the solid electrolyte in the electrode composite is not particularly limited and can be appropriately set considering the desired ionic conductivity, etc.

[0099] Challenge Supplements

[0100] The conduction aid may be, for example, a carbon material, metal particles, or a combination thereof. The carbon material may be, for example, a non-fibrous carbon material such as acetylene black (AB) or ketjen black (KB); a fibrous carbon material such as vapor-grown carbon fiber (VGCF), carbon nanotubes (CNT), or carbon nanofibers (CNF), or a combination thereof. The metal particles may be, for example, nickel, copper, iron, stainless steel, etc., or a combination thereof.

[0101] The content of the conductive aid in the electrode composite material is not particularly limited and can be appropriately set considering the desired conductivity, etc.

[0102] bookbinder

[0103] The binder may be, for example, a rubber-based binder such as butadiene rubber, hydrogenated butadiene rubber, styrene-butadiene rubber (SBR), hydrogenated styrene-butadiene rubber, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, acrylate-butadiene rubber (ABR), ethylene-propylene rubber; a fluoride-based binder such as polyvinylidene fluoride (PVDF), polyvinylidene-polyhexafluoropropylene copolymer (PVDF-HFP), polytetrafluoroethylene, fluororubber; a polyolefin-based thermoplastic resin such as polyethylene, polypropylene, polystyrene; an imide-based resin such as polyimide, polyamide-imide; an amide-based resin such as polyamide; an acrylic-based resin such as polymethyl acrylate, polyethyl acrylate; a methacrylate-based resin such as polymethyl methacrylate, polyethyl methacrylate; or a combination thereof.

[0104] The binder content in the electrode composite is not particularly limited and can be appropriately set considering the desired binding properties, etc.

[0105] Other ingredients

[0106] The electrode composite material may additionally include components other than those mentioned above, or may not include them.

[0107] battery

[0108] The battery of the present disclosure has an electrode active material layer, and the electrode active material layer contains the electrode composite of the present disclosure. The battery of the present disclosure may have a negative electrode current collector layer, a negative electrode active material layer, an electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order. In this case, the electrode active material layer containing the electrode composite of the present disclosure may be a negative electrode active material layer, a positive electrode active material layer, or particularly a negative electrode active material layer.

[0109] The battery of the present disclosure may be a liquid-based battery or a solid-state battery, and may be a solid-state battery in particular. Furthermore, regarding the present disclosure, "solid-state battery" means a battery comprising at least a solid electrolyte as an electrolyte, and thus, the solid-state battery may be a combination of a solid electrolyte and a liquid electrolyte as an electrolyte. In addition, the solid-state battery may be an all-solid-state battery, that is, a battery comprising only a solid electrolyte as an electrolyte.

[0110] The battery of the present disclosure may be a primary battery, a secondary battery, and in particular, a lithium-ion secondary battery.

[0111] The battery of the present disclosure may be restrained by restraining members, such as end plates, from both sides of the stacking direction of each layer. Examples of restraining methods include using the restraining torque of a bolt, but are not limited thereto.

[0112] Hereinafter, each element constituting the battery of the present disclosure is described. In addition, the following is an exemplary case in which the electrode active material layer containing the electrode composite material of the present disclosure is a negative electrode active material layer.

[0113] Bu-geuk, entire house floor

[0114] The negative electrode current collector layer may be in the form of a foil, plate, mesh, punched metal, foam, etc. The negative electrode current collector layer may be a metal foil or metal mesh, a carbon sheet, and in particular, a metal foil. The negative electrode current collector layer may be composed of multiple foils, sheets, etc.

[0115] The metal constituting the negative electrode current collector layer is not particularly limited and may be, for example, copper, nickel, chromium, gold, platinum, silver, aluminum, iron, titanium, zinc, cobalt, stainless steel, etc. In particular, the negative electrode current collector layer may include at least one metal selected from copper, nickel, and stainless steel.

[0116] For purposes such as adjusting resistance, any coating layer may be formed on the surface of the negative electrode current collector layer. Additionally, the negative electrode current collector layer may be a metal foil or substrate on which the above metal is plated or deposited. Furthermore, if the negative electrode current collector layer is composed of multiple metal foils, any layer may be formed between the multiple metal foils.

[0117] The thickness of the negative electrode current collector layer is not particularly limited and, for example, may be 0.1 μm or more or 1 μm or more, or 1 mm or less or 100 μm or less.

[0118] negative electrode active material layer

[0119] The negative electrode active material layer comprises the electrode composite of the present disclosure. For the electrode composite of the present disclosure, reference may be made to the description above. The negative electrode active material layer may be formed by molding the electrode composite of the present disclosure itself into a layer.

[0120] The thickness of the negative electrode active material layer is not particularly limited and, for example, may be 0.1 μm or more and 1000 μm or less.

[0121] solid electrolyte layer

[0122] The solid electrolyte layer comprises at least solid electrolyte particles and may optionally additionally include a binder, etc.

[0123] For solid electrolyte particles and binders, refer to the description above.

[0124] The thickness of the solid electrolyte layer is not particularly limited and, for example, may be 0.1 μm or more and 1000 μm or less.

[0125] positive electrode active material layer

[0126] The positive electrode active material layer comprises at least a positive electrode active material and may optionally additionally include a solid electrolyte, a conductivity aid, a binder, etc.

[0127] The positive electrode active material is not particularly limited and may be, for example, an oxide active material. Oxide active materials used in lithium-ion batteries include, for example, LiCoO2, LiMnO2, Li2NiMn3O8, LiVO2, LiCrO2, LiFePO4, LiCoPO4, LiNiO2, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 It may be O2, etc. In addition, a coating layer containing a Li ion-conducting oxide, such as LiNbO3, may be formed on the surface of these active materials.

[0128] The content of the positive electrode active material in the positive electrode active material layer is not particularly limited.

[0129] For solid electrolytes, conductive aids, and binders, refer to the description above.

[0130] The thickness of the positive electrode active material layer is not particularly limited and, for example, may be 0.1 μm or more and 1000 μm or less.

[0131] The entire floor of the main drama house

[0132] The positive electrode current collector layer may be in the form of a foil, plate, mesh, perforated metal, foam, etc. The positive electrode current collector layer may be a metal foil or metal mesh, and in particular, may be a metal foil. The positive electrode current collector layer may be composed of multiple foils.

[0133] The metal constituting the positive electrode current collector layer may be copper, nickel, chromium, gold, platinum, silver, aluminum, iron, titanium, zinc, cobalt, stainless steel, etc., and in particular, the positive electrode current collector layer may contain aluminum.

[0134] For purposes such as adjusting resistance, any coating layer may be formed on the surface of the positive electrode current collector layer. Additionally, the positive electrode current collector layer may be a metal foil or substrate on which the above-mentioned metal is plated or deposited. Furthermore, if the positive electrode current collector layer is composed of multiple metal foils, any layer may be formed between the multiple metal foils.

[0135] The thickness of the positive electrode current collector layer is not particularly limited and, for example, may be 0.1 μm or more or 1 μm or more, or 1 mm or less or 100 μm or less.

[0136] Other compositions

[0137] The battery may be one in which each of the above components is housed inside an outer body. Any known outer body may be adopted as the outer body of a battery. Additionally, multiple batteries may be electrically connected and stacked as desired to form a battery assembly. In this case, the battery assembly may be housed inside a known battery case. The battery may also be equipped with obvious components such as necessary terminals. The shape of the battery may be, for example, coin type, laminate (pouch) type, cylindrical type, prismatic type, etc.

[0138] A method for manufacturing a battery of the present disclosure is not particularly limited and, for example, includes forming an electrode active material layer containing an electrode composite material of the present disclosure.

[0139] An example of a method for forming an electrode active material layer containing an electrode composite is a method of mixing constituent materials such as electrode active material composite particles to obtain an electrode composite, and then dry molding or wet molding the obtained electrode composite.

[0140] The method for manufacturing a battery of the present disclosure may further include forming an electrode laminate by stacking a negative electrode current collector layer, a negative electrode active material layer, a solid electrolyte layer, a positive electrode active material layer, and a positive electrode current collector layer in this order.

[0141] Other components, such as terminals, are mounted on the electrode laminate as needed. A battery is obtained by housing the electrode laminate in a battery case and sealing it.

[0142] Examples

[0143] Synthesis of electrode active material composite particles

[0144] Provision of complex

[0145] 1 g of porous carbon material was introduced into the core tube of a CVD apparatus, and after depressurizing the core tube, it was heated to 500 °C. Subsequently, an oxygen line was inserted into a vessel containing tetraethoxysilane (TEOS), and oxygen was bubbled into the TEOS to introduce oxygen containing TEOS vapor into the core tube. By maintaining this state for 6 hours, a composite containing silicon dioxide (SiO2) within the porous carbon material was prepared. The core tube was cooled, and after purging the inside of the core tube with argon gas, the obtained composite was recovered.

[0146] Reduction of silicon oxide

[0147] The composite and Mg alloy were introduced into a reaction vessel. Subsequently, the reaction vessel was placed in a vacuum furnace, and while vacuuming the inside of the furnace with a rotary pump, the temperature was raised to 650°C over 1 hour and heated at this temperature for 10 hours. By doing so, SiO2 was reduced to prepare an electrode active material composite particle precursor containing silicon (Si) and magnesium oxide (MgO) within a porous carbon material. After cooling the vacuum furnace, the obtained electrode active material composite particle precursor was recovered.

[0148] Removal of magnesium oxide

[0149] 1 g of electrode active material composite particle precursor and 100 mL of 6 wt% hydrochloric acid were added to a beaker and stirred for 1 hour. The mixture was filtered under reduced pressure and then vacuum dried. Thus, electrode active material composite particles were obtained. In the obtained electrode active material composite particles, voids were formed between the Si in the pores of the Si-filled porous carbon material and the porous carbon material, and the silicon in the electrode active material composite particles was porous, thereby producing porous silicon.

[0150] Formation of the negative electrode active material layer

[0151] Butyl butyrate, a 5 wt% butyl butyrate solution of a polyvinylidene fluoride (PVDF)-based binder, vapor-grown carbon fiber (VGCF) as a conductivity aid, obtained electrode active material composite particles, and Li2S-P2S5-based glass ceramic as a sulfide solid electrolyte were added to a polypropylene container and stirred for 30 seconds using an ultrasonic dispersion device (SMT manufactured UH-50). Next, the container was shaken for 30 minutes using a shaker (Shibata Science Co., Ltd., TTM-1) to obtain a negative electrode composite material slurry. The obtained negative electrode composite material slurry was coated onto a copper (Cu) foil as a negative electrode current collector layer using a blade method with an applicator, and dried for 30 minutes on a hot plate heated to 100°C to form a negative electrode active material layer on the negative electrode current collector layer.

[0152] Formation of a solid electrolyte layer

[0153] A 5 wt% heptane solution of heptane and a butadiene rubber (BR)-based binder, and a Li2S-P2S5-based glass ceramic as a sulfide solid electrolyte were added to a polypropylene container and stirred for 30 seconds using an ultrasonic dispersion device (SMT, UH-50). Next, the container was shaken for 30 minutes using a shaker (Shibata Science Co., Ltd., TTM-1) to obtain a solid electrolyte slurry. The obtained solid electrolyte slurry was applied onto an aluminum (Al) foil as a release sheet using an applicator and the blade method. The Al foil coated with the solid electrolyte slurry was dried for 30 minutes on a hot plate heated to 100°C to form a solid electrolyte layer. Three solid electrolyte layers were prepared.

[0154] Formation of the positive electrode active material layer

[0155] In a polypropylene container, butyl butyrate, a 5 wt% butyl butyrate solution of a polyvinylidene fluoride (PVDF)-based binder, and LiNi with an average particle size of 6 μm as the positive electrode active material 1 / 3 Co 1 / 3 Mn 1 / 3 O2, a Li2S-P2S5-based glass ceramic as a sulfide solid electrolyte, and VGCF as a conductivity aid were added to a container and stirred for 30 seconds using an ultrasonic dispersion device (SMT, UH-50). Next, the container was shaken for 3 minutes using a shaker (Shibata Science Co., Ltd., TTM-1), stirred for 30 seconds using an ultrasonic dispersion device, and further shaken for 3 minutes using a shaker to obtain a positive electrode composite slurry. The obtained positive electrode composite slurry was applied onto an Al foil (Showa Electric Works, manufactured) as a positive electrode current collector layer using a blade method with an applicator. The Al foil coated with the positive electrode composite slurry was dried for 30 minutes on a hot plate heated to 100°C to form a positive electrode active material layer on the positive electrode current collector layer.

[0156] Battery manufacturing

[0157] The negative electrode current collector layer, the negative electrode active material layer, and the first solid electrolyte layer were laminated in this order. Additionally, the solid electrolyte layer was laminated such that the side without the Al foil facing the negative electrode active material layer. This laminate was set in a roll press and pressed at a press pressure of 60 kN / cm and a press temperature of 25 ℃ to obtain a densified negative electrode laminate.

[0158] A positive electrode current collector layer, a positive electrode active material layer, and a second solid electrolyte layer were laminated in this order. Additionally, the solid electrolyte layer was laminated such that the side without the Al foil facing the positive electrode active material layer. This laminate was set in a roll press and pressed at a press pressure of 100 kN / cm and a press temperature of 165 ℃ to obtain a positive electrode laminate.

[0159] The area of ​​the negative electrode stack was larger than the area of ​​the positive electrode stack.

[0160] An Al foil acting as a release sheet was peeled off from the surface of the first solid electrolyte layer. A third solid electrolyte layer was then laminated onto the first solid electrolyte layer in the exposed negative electrode laminate. This laminate was set in a flat single-axis press and subjected to temporary pressing at 100 MPa and 25°C for 10 seconds. The Al foil was peeled off from the third solid electrolyte layer to obtain a negative electrode laminate with an additionally laminated third solid electrolyte layer.

[0161] An Al foil serving as a release sheet was peeled off from the surface of the second solid electrolyte layer. The second solid electrolyte layer was laminated onto the third solid electrolyte layer. This laminate was set in a planar single-axis press and pressed for 1 minute at a press pressure of 200 MPa and a press temperature of 120 °C. By doing so, the all-solid-state battery of Example 1 was obtained.

[0162] Comparative example

[0163] In the process of providing the composite, monosilane gas was introduced into the core tube instead of oxygen containing TEOS vapor, except that the process was the same as in the example, thereby obtaining the electrode active material composite particles of the comparative example and an all-solid-state battery containing the same.

[0164] Acquisition of crafting distribution

[0165] For the electrode active material composite particles and porous carbon materials of each example, after measuring the N2 adsorption isotherms, the cumulative pore distribution and the fine pore distribution were obtained by the BJH (Barrett-Joyner-Halenda) method. For the measurements by the BJH method, the BELSORPMAXX, a specific surface area and pore distribution measuring device manufactured by Microtrax, was used. The obtained cumulative pore distribution and fine pore distribution are shown in Figures 1 and 2, respectively. From the pore distribution obtained in this way, a pore volume of a predetermined size was determined.

[0166] Evaluation of the increase in confinement pressure

[0167] Using a restraint jig, the battery of each example manufactured was restrained to a predetermined restraint pressure, and the increase in restraint pressure was measured when it was charged to 4.55 V at a constant current-constant voltage rate of 10 hours (1 / 10C). The increase in restraint pressure is the difference between the maximum and minimum values ​​of the restraint pressure and is an indicator of the increase in the volume of the battery.

[0168] The results are shown in Table 1. In Table 1, the value of the increase in confining pressure of the example is shown as a relative value when the value of the comparative example is set to 1.00.

[0169]

[0170] As shown in Table 1, in the battery of the example containing electrode active material composite particles having pores of 10 nm or less and 0.22 cc / g or more, the increase in confining pressure was small.

[0171] As shown in Fig. 1, the electrode active material composite particles included in the battery of the example had pores of 2 nm or less and 0.25 cc / g or more and 0.35 cc / g or less.

[0172] As shown in Figures 1 and 2, the pore distribution of the electrode active material composite particles included in the battery of the example was different from the pore distribution of the raw material porous carbon material. This suggests that the electrode active material composite particles included in the battery of the example contain, in addition to the pores of the porous carbon material that are not filled with silicon at all and / or sufficiently and are therefore remaining, voids formed between silicon and the porous carbon material in the pores of the silicon-filled porous carbon material, and pores of porous silicon (porous silicon).

Claims

Claim 1 An electrode active material composite particle comprising a porous carbon material and silicon retained within the porous carbon material, and having pores of 10 nm or less and 0.22 cc / g or more when measured by a gas adsorption method. Claim 2 In claim 1, an electrode active material composite particle having pores of 2 nm or less and 0.15 cc / g or more when measured by gas adsorption method. Claim 3 An electrode active material composite particle according to claim 1, having pores of 10 nm or less with a g of 0.50 cc / g or more and 0.60 cc / g or less when measured by a gas adsorption method, and also having pores of 2 nm or less with a g of 0.25 cc / g or more and 0.35 cc / g or less. Claim 4 An electrode composite comprising electrode active material composite particles described in any one of claims 1 to 3. Claim 5 A battery having an electrode active material layer, wherein the electrode active material layer contains the electrode composite material described in claim 4.

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