All-solid battery

Abstract

To provide an all-solid battery in which the performance balance between capacity and a resistance value is improved.SOLUTION: An all-solid battery includes: a positive electrode including a positive electrode active material layer including a positive electrode active material, a positive electrode binder, and a solid electrolyte; a solid electrolyte layer; and a negative electrode including a negative electrode active material layer. The positive electrode active material includes single-crystal particles (A) formed of lithium-nickel-cobalt-manganese complex oxide. The positive electrode binder includes a fluorine elastomer (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an all-solid-state battery. [Background technology]

[0002] An all-solid-state battery includes, for example, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer in this order. Patent Document 1 describes a technique relating to all-solid-state batteries.

[0003] Patent Document 1 discloses a method for producing a positive electrode for a solid state battery, the method comprising the steps of: mixing a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a solvent to prepare a positive electrode slurry; applying the prepared positive electrode slurry; and drying the applied positive electrode slurry, the solvent being butyl butyrate; and the binder being a copolymer composed of vinylidene fluoride (VDF) monomer units and hexafluoropropylene (HFP) monomer units, wherein the molar ratio of the HFP monomer units to the total of the VDF monomer units and the HFP monomer units is 10% or more and 20% or less. The objective of this method is to prevent deterioration of the sulfide-based solid electrolyte, ensure sufficient adhesive strength between the current collector and the positive electrode layer, and prevent a decrease in battery output due to rapid drying. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-25027 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides an all-solid-state battery with an improved performance balance between capacity and resistance value. [Means for solving the problem]

[0006] According to the present invention, the following all-solid-state battery is provided.

[0007] [1] a positive electrode including a positive electrode active material layer including a positive electrode active material, a positive electrode binder, and a solid electrolyte; a solid electrolyte layer; a negative electrode including a negative electrode active material layer; Including, the positive electrode active material contains single-crystal particles (A) composed of a lithium-nickel-cobalt-manganese composite oxide, The positive electrode binder comprises a fluorine-based elastomer (B). [2] The all-solid-state battery according to [1], wherein the lithium-nickel-cobalt-manganese composite oxide contains a composite oxide represented by the following formula (1): Li a Ni b Co c Mn d M e O2(1) (In the formula (1), M represents one or more elements selected from the group consisting of Al, Mg, Na, Co, K, W, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo; and 0.5≦a≦1.5, 0.6≦b<1.0, 0.5≦b≦1.5, 0.6≦b<1.0, 0.5≦a ... <c<0.2、0<d<0.2、0≦e<1.0) [3] The all-solid-state battery according to [1] or [2], wherein the content of the single-crystal particles (A) in the positive electrode active material is 50 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of the content of the positive electrode active material in the positive electrode active material layer. [4] The average particle diameter d of the positive electrode active material in the volume-based particle size distribution measured by a laser diffraction scattering particle size distribution measurement method 50 The all-solid-state battery according to any one of [1] to [3], wherein the thickness is 0.1 μm or more and 30 μm or less. [5] The all-solid-state battery according to any one of [1] to [4], wherein the fluorine-based elastomer (B) contains a structural unit derived from vinylidene fluoride (VdF). [6] The all-solid-state battery according to [5], wherein the fluorine-based elastomer (B) further contains one or more structural units selected from the group consisting of structural units derived from hexafluoropropylene (HFP), structural units derived from trifluoropropylene (TFP), structural units derived from tetrafluoroethylene (TFE), structural units derived from 2,3,3,3-tetrafluoropropylene, structural units derived from 1,3,3,3-tetrafluoropropylene, and structural units derived from perfluoroalkyl vinyl ether (PAVE). [7] The all-solid-state battery according to any one of [1] to [6], wherein the fluorine-based elastomer (B) includes one or more selected from the group consisting of a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP), and a copolymer of vinylidene fluoride (VdF) and trifluoropropylene (TFP). [8] The all-solid-state battery according to any one of [1] to [7], wherein the content of structural units derived from vinylidene fluoride (VdF) in the fluorine-based elastomer (B) is 20 mol % or more. [9] The all-solid-state battery according to any one of [1] to [8], wherein the fluorine-based elastomer (B) has a mass average molecular weight (Mw) of 10,000 or more and 10,000,000 or less.

[10] The all-solid-state battery according to any one of [1] to [9], wherein the content of the positive electrode binder in the positive electrode active material layer is 0.5 parts by mass or more and 8.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

[11] The all-solid-state battery according to any one of [1] to

[10] , wherein the content of the positive electrode active material in the positive electrode active material layer is 50.0 parts by mass or more and 90.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

[12] The all-solid-state battery according to any one of [1] to

[11] , wherein the solid electrolyte in the positive electrode active material layer contains one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte.

[13] The all-solid-state battery according to any one of [1] to

[12] , wherein the content of the solid electrolyte in the positive electrode active material layer is 5.0 parts by mass or more and 40.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

[14] The all-solid-state battery according to any one of [1] to

[13] , wherein the positive electrode active material layer further contains a conductive additive.

[15] The all-solid-state battery according to

[14] , wherein the conductive additive comprises one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes.

[16]

[14] The all-solid-state battery according to

[15] or

[16] , wherein the content of the conductive additive in the positive electrode active material layer is 0.1 parts by mass or more and 10.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an all-solid-state battery with an improved performance balance between capacity and resistance value. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing an example of the structure of an all-solid-state battery according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes an embodiment of the present invention. Note that the shapes, sizes, and layouts of the various components in the drawings are merely schematic representations that allow the present invention to be understood, and are not to scale. Furthermore, unless otherwise specified, "to" in a numerical range indicates a range from above to below.

[0011] <All-solid-state battery> The all-solid-state battery of this embodiment includes a positive electrode including a positive electrode active material layer containing a positive electrode active material, a positive electrode binder, and a solid electrolyte, a solid electrolyte layer, and a negative electrode including a negative electrode active material layer, wherein the positive electrode active material includes single crystal particles (A) (hereinafter, may be abbreviated as "single crystal particles (A)") made of a lithium-nickel-cobalt-manganese composite oxide, and the positive electrode binder includes a fluorine-based elastomer (B).

[0012] As a result of investigations by the present inventors, it has become clear that by using a fluorine-based elastomer as a positive electrode binder, the performance balance between the capacity and resistance value of an all-solid-state battery can be improved, even when single-crystal particles composed of a lithium-nickel-cobalt-manganese composite oxide are used as the positive electrode active material. That is, according to this embodiment, it is possible to provide an all-solid-state battery with an improved performance balance between capacity and resistance value.

[0013] (positive electrode) The positive electrode of this embodiment includes a positive electrode active material layer. The positive electrode active material layer of this embodiment includes a positive electrode active material, a positive electrode binder, and a solid electrolyte.

[0014] The positive electrode active material of this embodiment contains single crystal particles (A) made of a lithium-nickel-cobalt-manganese composite oxide. In this embodiment, a single-crystal particle is a particle that is composed of a single crystal grain and does not show grain boundaries when observed under an electron microscope at 1000 to 5000 magnifications. Even when multiple single-crystal particles are closely attached, they are also included in the category of single-crystal particles. On the other hand, in this embodiment, a polycrystalline particle is a particle in which multiple crystal grains with different crystal orientations and grain boundaries are observed within the solid when observed under an electron microscope at 1000 to 5000 magnifications.

[0015] The lithium-nickel-cobalt-manganese composite oxide of this embodiment preferably contains a composite oxide represented by the following formula (1).

[0016] Li a Ni b Co c Mn d M e O2(1) In the formula (1), M is one or more selected from the group consisting of Al, Mg, Na, Co, K, W, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 0.5 ≦ a ≦ 1.5, 0.6 ≦ b < 1.0, 0 < c < 0.2, 0 < d < 0.2, 0 ≦ e < 1.0.

[0017] In the composite oxide of the formula (1), 0.5 ≦ a ≦ 1.5, preferably 0.6 ≦ a ≦ 1.4, more preferably 0.7 ≦ a ≦ 1.3, still more preferably 0.8 ≦ a ≦ 1.2, still more preferably 0.9 ≦ a ≦ 1.1, and still more preferably a = 1.0.

[0018] Also, in the composite oxide of the formula (1), 0.6 ≦ b < 1.0, and from the viewpoint of further improving the capacity of the all - solid - state battery, preferably 0.65 ≦ b < 1.0, more preferably 0.7 ≦ b < 1.0, still more preferably 0.75 ≦ b < 1.0, and still more preferably 0.8 ≦ b ≦ 0.95.

[0019] In the composite oxide of the formula (1), 0 < c < 0.2, preferably 0.01 ≦ c ≦ 0.15, more preferably 0.02 ≦ c ≦ 0.15, and still more preferably 0.03 ≦ c ≦ 0.1.

[0020] In the composite oxide of the formula (1), 0 < d < 0.2, preferably 0.01 ≦ d ≦ 0.15, more preferably 0.02 ≦ d ≦ 0.15, and still more preferably 0.02 ≦ d ≦ 0.1.

[0021] In the composite oxide of the formula (1), **********0 ≦ e < 1.0, preferably 0 ≦ e ≦ 0.5, more preferably 0 ≦ e ≦ 0.3, still more preferably 0 ≦ e ≦ 0.2, still more preferably 0 ≦ e ≦ 0.1, and still more preferably e = 0. It should be noted that there is an asterisk in the original text at the position of "**********" which seems to be an error or an incomplete part. I have translated it as accurately as possible based on the overall context. If this is a critical error in the original, it may need to be corrected in the source material for a more precise translation.

[0022] The positive electrode active material of this embodiment may further contain a positive electrode active material other than the single crystal particles (A) made of lithium-nickel-cobalt-manganese composite oxide. The positive electrode active material other than the single crystal particles (A) is not particularly limited, and examples thereof include composite oxides of lithium and transition metals such as lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-cobalt-manganese composite oxide other than the single crystal particles (A), lithium-nickel-manganese-aluminum composite oxide, and lithium-nickel-cobalt-manganese-aluminum composite oxide; transition metal sulfides such as TiS2, FeS, and MoS2; MnO, VO, and VO. 13 and TiO2 and olivine-type lithium phosphate, and from the viewpoint of being able to improve the working potential, capacity, durability, and energy density, preferably the material contains one or more selected from the group consisting of olivine-type lithium iron phosphate, lithium-nickel composite oxide, lithium-cobalt composite oxide, lithium-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel-cobalt composite oxide, lithium-nickel-aluminum composite oxide, lithium-nickel-cobalt-aluminum composite oxide, lithium-nickel-manganese-cobalt composite oxide, lithium-nickel-manganese-aluminum composite oxide, and lithium-nickel-cobalt-manganese-aluminum composite oxide. Here, the olivine-type lithium phosphate contains, for example, at least one element selected from the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe, as well as lithium, phosphorus, and oxygen.

[0023] When the content of the positive electrode active material in the positive electrode active material layer is taken as 100 parts by mass, the content of the single crystal particles (A) in the positive electrode active material of this embodiment is, from the viewpoint of further improving the performance balance between the capacity and the resistance value of the all-solid-state battery, preferably 50 parts by mass or more and 100 parts by mass or less, more preferably 60 parts by mass or more and 100 parts by mass or less, even more preferably 70 parts by mass or more and 100 parts by mass or less, even more preferably 80 parts by mass or more and 100 parts by mass or less, even more preferably 90 parts by mass or more and 100 parts by mass or less, and even more preferably 95 parts by mass or more and 100 parts by mass or less.

[0024] The average particle diameter d of the positive electrode active material of this embodiment 50 is preferably 0.1 μm or more and 30 μm or less, more preferably 0.3 μm or more and 20 μm or less, even more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1.0 μm or more and 10.0 μm or less. 50 means the particle size at 50% cumulative value in the particle size distribution (volume basis) determined by the laser diffraction scattering method.

[0025] When the entire cathode active material layer is taken as 100 parts by mass, from the viewpoint of further improving the capacity of the all-solid-state battery, the content of the cathode active material in the cathode active material layer of this embodiment is preferably 50.0 parts by mass or more and 90.0 parts by mass or less, more preferably 55.0 parts by mass or more and 90.0 parts by mass or less, even more preferably 60.0 parts by mass or more and 90.0 parts by mass or less, even more preferably 65.0 parts by mass or more and 90.0 parts by mass or less, even more preferably 70.0 parts by mass or more and 88.0 parts by mass or less, and even more preferably 75.0 parts by mass or more and 85.0 parts by mass or less.

[0026] The positive electrode binder of this embodiment contains a fluorine-based elastomer (B).

[0027] From the viewpoint of further improving the performance balance between the capacity and resistance value of the all-solid-state battery, the fluorine-based elastomer (B) preferably contains a constituent unit derived from vinylidene fluoride (VdF), and more preferably contains a constituent unit derived from vinylidene fluoride (VdF) and one or more constituent units selected from the group consisting of constituent units derived from hexafluoropropylene (HFP), constituent units derived from trifluoropropylene (TFP), constituent units derived from tetrafluoroethylene (TFE), constituent units derived from 2,3,3,3-tetrafluoropropylene, constituent units derived from 1,3,3,3-tetrafluoropropylene, and constituent units derived from perfluoroalkyl vinyl ether (PAVE). Furthermore, from the viewpoint of further improving the performance balance between the capacity and resistance value of the all-solid-state battery, the fluorine-based elastomer (B) more preferably contains one or more selected from the group consisting of a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP) and a copolymer of vinylidene fluoride (VdF) and trifluoropropylene (TFP), and more preferably contains a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP).

[0028] The mass average molecular weight (Mw) of the fluorine-based elastomer (B) is preferably 10,000 or more and 10,000,000 or less, more preferably 30,000 or more and 5,000,000 or less, even more preferably 50,000 or more and 1,000,000 or less, even more preferably 80,000 or more and 800,000 or less, and even more preferably 100,000 or more and 500,000 or less.

[0029] The content of structural units derived from vinylidene fluoride (VdF) in the fluorine-based elastomer (B) is preferably 20 mol% or more, more preferably 20 mol% or more and 95 mol% or less, even more preferably 30 mol% or more and 90 mol% or less, even more preferably 40 mol% or more and 90 mol% or less, even more preferably 60 mol% or more and 85 mol% or less, and even more preferably 70 mol% or more and 85 mol% or less.

[0030] The content of the positive electrode binder in the positive electrode active material layer of this embodiment is preferably 0.5 parts by mass or more and 8.0 parts by mass or less, more preferably 0.8 parts by mass or more and 7.5 parts by mass or less, even more preferably 1.0 parts by mass or more and 7.0 parts by mass or less, and still more preferably 1.5 parts by mass or more and 6.5 parts by mass or less, from the viewpoint of further improving the performance balance between the capacity and the resistance value of the all-solid-state battery, when the entire positive electrode active material layer is taken as 100 parts by mass.

[0031] The solid electrolyte in the positive electrode active material layer of the present embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0032] Examples of oxide-based solid electrolytes include NASICON-type solid electrolyte materials such as LiTi2(PO4)3, LiZr2(PO4)3, and LiGe2(PO4)3; 0.5+x Li 0.5-3x ) Perovskite-type solid electrolyte materials such as TiO3; one or more selected from the group consisting of Li2O-P2O5 materials, Li2O-P2O5-Li3N materials, etc.

[0033] Examples of sulfide-based solid electrolytes include Li2S-P2S5 materials, Li2S-SiS2 materials, Li2S-GeS2 materials, Li2S-Al2S3 materials, Li2S-SiS2-Li3PO4 materials, Li2S-P2S5-GeS2 materials, Li2S-Li2O-P2S5-SiS2 materials, Li2S-GeS2-P2S5-SiS2 materials, Li2S-SnS2-P2S5-SiS2 materials, Li2S-P2S5-Li3N materials, and Li2S 2+X -P4S3 material, Li2S-P2S5-P4S3 material, LiPO4-Li2S-SiS material, Li3PS4, Li3PO4-Li2S-Si2S material, Li3PO4-Li2S-SiS2 material, LiI-L i2S-B2S3 material, LiI-Li2S-SiS2 material, LiI-Li2S-P2S5 material, LiI-Li2S-P2O5 material, LiI-Li3PO4-P2S5Li2S-P2S5-LiCl material, Li 7-x PS 6-x Clx (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2), Li 7-x PS 6-x I x (where 0≦x≦2), Li 10 GeP2S 12 , and Li 3.25 Ge 0.25 P 0.75 S4, more preferably Li 7-x PS 6-x Cl x (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2) and Li 7-x PS 6-x I x (where 0≦x≦2), more preferably contains one or more selected from the group consisting of Li6PS5Cl, Li6PS5Br and Li6PS5I, and even more preferably contains Li6PS5Cl.

[0034] The polymer-based solid electrolyte material includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0035] When the entire cathode active material layer is taken as 100 parts by mass, the content of the solid electrolyte in the cathode active material layer of this embodiment is, from the viewpoint of further improving the performance balance between the capacity and the resistance value of the all-solid-state battery, preferably 5.0 parts by mass or more and 40.0 parts by mass or less, more preferably 8.0 parts by mass or more and 35.0 parts by mass or less, even more preferably 10.0 parts by mass or more and 33.0 parts by mass or less, even more preferably 12.0 parts by mass or more and 30.0 parts by mass or less, and even more preferably 14.0 parts by mass or more and 28.0 parts by mass or less.

[0036] The positive electrode active material layer of this embodiment preferably further contains a conductive additive, from the viewpoint of further reducing the resistance value of the all-solid-state battery. From the viewpoint of further reducing the resistance value of the all-solid-state battery, the conductive additive in the positive electrode active material layer of the present embodiment includes one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably includes carbon black.

[0037] When the entire positive electrode active material layer is taken as 100 parts by mass, the content of the conductive additive in the positive electrode active material layer of this embodiment is, from the viewpoint of further improving the performance balance between the capacity and the resistance value of the all-solid-state battery, preferably 0.1 parts by mass or more and 10.0 parts by mass or less, more preferably 0.3 parts by mass or more and 5.0 parts by mass or less, even more preferably 0.5 parts by mass or more and 4.0 parts by mass or less, even more preferably 0.8 parts by mass or more and 3.0 parts by mass or less, and even more preferably 1.0 parts by mass or more and 2.0 parts by mass or less.

[0038] The density of the positive electrode active material layer of this embodiment is preferably 1.0 g / cm 3 More than 5.0g / cm 3 or less, more preferably 2.0 g / cm 3 More than 4.0g / cm 3 The following is the result.

[0039] The thickness of the positive electrode active material layer is not particularly limited, but is, for example, preferably from 1 μm to 150 μm, more preferably from 5 μm to 100 μm, and even more preferably from 10 μm to 80 μm.

[0040] The positive electrode of this embodiment may further include a positive electrode current collector. The positive electrode current collector includes, for example, one or more selected from the group consisting of aluminum, stainless steel, nickel, titanium, and alloys thereof. The shape of the positive electrode current collector may be, for example, a foil, a flat plate, or a mesh. The thickness of the positive electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0041] The positive electrode of this embodiment can be manufactured, for example, by dissolving or dispersing the components constituting the positive electrode active material layer in a solvent to produce a positive electrode slurry, applying the positive electrode slurry to at least one surface of the positive electrode current collector, and then drying and rolling. Also, the positive electrode of this embodiment can be manufactured, for example, by applying and drying the positive electrode slurry on a support, and then laminating the film obtained by peeling from this support on the positive electrode current collector.

[0042] (Negative electrode) The negative electrode of this embodiment includes a negative electrode active material layer. The negative electrode active material layer of this embodiment includes, for example, a negative electrode active material, and may further include one or more selected from the group consisting of a binder for the negative electrode, a solid electrolyte, and a conductive assistant.

[0043] The negative electrode active material of this embodiment is not particularly limited, and includes, for example, carbon materials such as graphite, amorphous carbon, diamond-like carbon, fullerene, carbon nanotubes, and carbon nanohorns; lithium-based metal materials such as metallic lithium and lithium alloys; Si, SiO2, SiO x (0 < x ≦ 2), Si-based materials such as Si-containing composite materials, and one or more selected from the group consisting of conductive polymers such as polyacene, polyacetylene, and polypyrrole, and more preferably includes a lithium-based metal material.

[0044] The content of the negative electrode active material in the negative electrode active material layer of this embodiment is preferably 70 parts by mass or more and 100 parts by mass or less, more preferably 80 parts by mass or more and 100 parts by mass or less, and even more preferably 90 parts by mass or more and 100 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0045] The negative electrode active material layer of this embodiment may contain one or more binder resins selected from the group consisting of rubber-based binders and acrylic-based binders. Such binder resins may be in the form of an emulsion. When water is used as the solvent, it is preferable to use an aqueous binder and a thickener such as CMC (carboxymethyl cellulose) in combination.

[0046] The content of the binder resin in the negative electrode active material layer of this embodiment may be, for example, 1 part by mass or more and 10 parts by mass or less, or 3 parts by mass or more and 6 parts by mass or less, when the total amount of the negative electrode active material layer is 100 parts by mass.

[0047] The solid electrolyte in the negative electrode active material layer of the present embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0048] Examples of oxide-based solid electrolytes include NASICON-type solid electrolyte materials such as LiTi2(PO4)3, LiZr2(PO4)3, and LiGe2(PO4)3; 0.5+x Li 0.5-3x ) Perovskite-type solid electrolyte materials such as TiO3; one or more selected from the group consisting of Li2O-P2O5 materials, Li2O-P2O5-Li3N materials, etc.

[0049] Examples of sulfide-based solid electrolytes include Li2S-P2S5 materials, Li2S-SiS2 materials, Li2S-GeS2 materials, Li2S-Al2S3 materials, Li2S-SiS2-Li3PO4 materials, Li2S-P2S5-GeS2 materials, Li2S-Li2O-P2S5-SiS2 materials, Li2S-GeS2-P2S5-SiS2 materials, Li2S-SnS2-P2S5-SiS2 materials, Li2S-P2S5-Li3N materials, and Li2S 2+X -P4S3 material, Li2S-P2S5-P4S3 material, LiPO4-Li2S-SiS material, Li3PS4, Li3PO4-Li2S-Si2S material, Li3PO4-Li2S-SiS2 material, LiI-L i2S-B2S3 material, LiI-Li2S-SiS2 material, LiI-Li2S-P2S5 material, LiI-Li2S-P2O5 material, LiI-Li3PO4-P2S5Li2S-P2S5-LiCl material, Li 7-x PS 6-x Cl x (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2), Li 7-x PS 6-x I x (where 0≦x≦2), Li 10 GeP2S 12 , and Li 3.25 Ge 0.25 P 0.75 S4, more preferably Li 7-x PS 6-x Cl x (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2) and Li 7-x PS 6-x I x (where 0≦x≦2), more preferably contains one or more selected from the group consisting of Li6PS5Cl, Li6PS5Br and Li6PS5I, and even more preferably contains Li6PS5Cl.

[0050] The polymer-based solid electrolyte material includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0051] From the viewpoint of further reducing the resistance value of the all-solid-state battery, the conductive additive in the negative electrode active material layer of the present embodiment includes one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes, and more preferably includes carbon black.

[0052] The content of the conductive additive in the negative electrode active material layer of this embodiment is preferably 0.05 parts by mass or more and 10 parts by mass or less, and more preferably 0.5 parts by mass or more and 5.0 parts by mass or less, from the viewpoint of further improving the performance balance between the capacity and the resistance value of the all-solid-state battery, when the entire negative electrode active material layer is taken as 100 parts by mass.

[0053] In the negative electrode active material layer, electrode additives generally used for forming electrodes, such as thickeners, dispersants, and stabilizers, can be used as appropriate.

[0054] The density of the negative electrode active material layer of this embodiment is preferably 0.5 g / cm 3 More than 3.0g / cm 3 or less, more preferably 1.2 g / cm 3 More than 2.0g / cm 3 The following is the result.

[0055] The thickness of the negative electrode active material layer of this embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0056] The negative electrode current collector contains, for example, one or more selected from the group consisting of copper, stainless steel, nickel, titanium, and alloys thereof. The negative electrode current collector may be in the form of, for example, a foil, a flat plate, or a mesh. The thickness of the negative electrode current collector is, for example, 1 μm or more and 50 μm or less.

[0057] (solid electrolyte layer) The solid electrolyte layer of this embodiment includes a solid electrolyte.

[0058] The solid electrolyte in the solid electrolyte layer of the present embodiment preferably includes one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte, and more preferably includes a sulfide-based solid electrolyte.

[0059] Examples of oxide-based solid electrolytes include NASICON-type solid electrolyte materials such as LiTi2(PO4)3, LiZr2(PO4)3, and LiGe2(PO4)3; 0.5+x Li 0.5-3x ) Perovskite-type solid electrolyte materials such as TiO3; one or more selected from the group consisting of Li2O-P2O5 materials, Li2O-P2O5-Li3N materials, etc.

[0060] Examples of sulfide-based solid electrolytes include Li2S-P2S5 materials, Li2S-SiS2 materials, Li2S-GeS2 materials, Li2S-Al2S3 materials, Li2S-SiS2-Li3PO4 materials, Li2S-P2S5-GeS2 materials, Li2S-Li2O-P2S5-SiS2 materials, Li2S-GeS2-P2S5-SiS2 materials, Li2S-SnS2-P2S5-SiS2 materials, Li2S-P2S5-Li3N materials, and Li2S 2+X -P4S3 material, Li2S-P2S5-P4S3 material, LiPO4-Li2S-SiS material, Li3PS4, Li3PO4-Li2S-Si2S material, Li3PO4-Li2S-SiS2 material, LiI-L i2S-B2S3 material, LiI-Li2S-SiS2 material, LiI-Li2S-P2S5 material, LiI-Li2S-P2O5 material, LiI-Li3PO4-P2S5Li2S-P2S5-LiCl material, Li7-x PS 6-x Cl x (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2), Li 7-x PS 6-x I x (where 0≦x≦2), Li 10 GeP2S 12 , and Li 3.25 Ge 0.25 P 0.75 S4, more preferably Li 7-x PS 6-x Cl x (where 0≦x≦2), Li 7-x PS 6-x Br x (where 0≦x≦2) and Li 7-x PS 6-x I x (where 0≦x≦2), more preferably contains one or more selected from the group consisting of Li6PS5Cl, Li6PS5Br and Li6PS5I, and even more preferably contains Li6PS5Cl.

[0061] The polymer-based solid electrolyte material includes one or more selected from the group consisting of polyether-based electrolyte materials such as polyethylene oxide, polypropylene oxide, ethylene oxide-propylene copolymer, and dimethylsiloxane-ethylene oxide copolymer; gel polymer electrolyte materials such as polyacrylonitrile, polyvinylidene fluoride, and vinylidene fluoride-hexafluoropropylene polymer; and polymer solid electrolyte materials using hyperbranched polymers.

[0062] The content of the solid electrolyte in the solid electrolyte layer of the present embodiment is preferably 80 parts by mass or more and 100 parts by mass or less, and more preferably 90 parts by mass or more and 100 parts by mass or less, when the total amount of the solid electrolyte layer is 100 parts by mass.

[0063] The thickness of the solid electrolyte layer of this embodiment is preferably 1 μm or more and 150 μm or less, more preferably 5 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less.

[0064] (Any configuration of all-solid-state battery) The all-solid-state battery of this embodiment may further include an exterior body. Examples of the exterior body include an aluminum laminate film, a strong aluminum can case, and a cylindrical aluminum exterior body.

[0065] The all-solid-state battery of this embodiment may further include a positive electrode terminal and a negative electrode terminal. The positive electrode terminal may be made of, for example, aluminum or an aluminum alloy, and the negative electrode terminal may be made of, for example, copper or a copper alloy, or a nickel-plated copper or copper alloy.

[0066] (Manufacturing method of all-solid-state batteries) The method for producing the all-solid-state battery is not particularly limited, and known methods can be applied. First, the preparation of the negative electrode will be described. The negative electrode can be prepared by a known method. Regardless of the method used to prepare the negative electrode, it is preferable to prepare it in a low-moisture environment under dew point control in order to suppress adsorption of moisture into the solid electrolyte.

[0067] When using a negative electrode in which a negative electrode active material layer is formed on a negative electrode current collector, a slurry in which a negative electrode active material, a solid electrolyte, and a binder are dispersed in a dehydrated organic solvent is applied to part or all of the surface of a negative electrode current collector such as copper foil, followed by drying to obtain a negative electrode precursor sheet. The obtained negative electrode precursor sheet can be compressed using a press molding method such as a roll press, a uniaxial press, a rubber press, or an isostatic press (CIP, WIP) to obtain a negative electrode sheet. The organic solvent preferably includes one or more solvents selected from the group consisting of tertiary amine solvents such as acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, and triethylamine, as well as heptane, hexane, tetrahydrofuran, toluene, and N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, all of which are preferably dehydrated.

[0068] The negative electrode can be obtained by placing a metallic lithium layer (negative electrode active material layer) such as lithium foil on part or all of a negative electrode current collector such as stainless steel foil, and then adhering them together by rolling or other processing.

[0069] Next, a solid electrolyte layer is formed on the surface of the negative electrode. When a sulfide-based solid electrolyte is used, it is preferably formed in a low-moisture environment under dew point control to prevent moisture adsorption.

[0070] The solid electrolyte layer can be formed on the surface of the negative electrode by, for example, applying a slurry of a solid electrolyte dispersed in an organic solvent to the surface of a negative electrode active material layer formed on a negative electrode current collector and drying the slurry. The organic solvent may include, for example, one or more selected from the group consisting of acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, triethylamine, and other tertiary amine solvents, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, as well as ether solvents, thiol solvents, and butyl butyrate, and it is preferable that all of the organic solvents have been dehydrated.

[0071] Next, the stacked negative electrode and solid electrolyte layer are compressed using a press molding method such as a vacuum laminator, roll press, uniaxial press, rubber press, or isostatic pressing (CIP, WIP) to obtain a negative electrode-solid electrolyte layer laminate. When the solid electrolyte layer is stacked together with a substrate layer such as a polyester sheet and pressurized, the substrate layer is peeled off from the solid electrolyte layer. In this case, it is also preferable to use a substrate layer whose surface is coated with a release agent such as silicone to facilitate peeling of the substrate layer from the solid electrolyte layer.

[0072] Next, the fabrication of the positive electrode will be described. Regardless of the method used to fabricate the positive electrode, it is preferable to fabricate the positive electrode in a low moisture environment under dew point control in order to suppress moisture adsorption.

[0073] The positive electrode of this embodiment can be produced, for example, by dissolving or dispersing the components constituting the positive electrode active material layer in a solvent to produce a positive electrode slurry, applying the positive electrode slurry to at least one surface of a positive electrode current collector, drying, and rolling. Alternatively, the positive electrode of this embodiment can be produced, for example, by applying the positive electrode slurry to a support, drying it, peeling it from the support, and laminating the resulting film on the positive electrode current collector. The solvent preferably includes one or more solvents selected from the group consisting of tertiary amine solvents such as acetonitrile, xylene, dimethoxyethane, dimethyl carbonate, and triethylamine, heptane, hexane, tetrahydrofuran, toluene, N-methylpyrrolidone, ether solvents, thiol solvents, and butyl butyrate, and each of these solvents is preferably dehydrated.

[0074] A positive electrode is laminated on the negative electrode-solid electrolyte layer laminate to obtain an electrode laminate precursor. When a sulfide-based solid electrolyte is used as the solid electrolyte, the ionic conductivity of the solid electrolyte may decrease due to exposure to moisture. Therefore, after obtaining the electrode laminate precursor, it is preferable to compress the electrode laminate precursor using a vacuum laminator, roll press, uniaxial press, rubber press, isostatic pressing (CIP, WIP), or other method to obtain an electrode laminate.

[0075] The resulting electrode laminate is preferably quickly sealed in an exterior housing. One end of a rectangular metal plate serving as a negative electrode terminal is attached to the negative electrode current collector, and one end of a rectangular metal terminal serving as a positive electrode terminal is attached to the positive electrode current collector, and then the electrode laminate is housed in an aluminum exterior housing. A resin layer such as polyolefin is preferably formed on at least the surface of the inner surface of the exterior housing facing the electrode laminate. The resin layer is heated to melt the resin and solidify it again, and the electrode laminate is sealed in the aluminum exterior housing. At this time, the other end of the positive electrode terminal and the other end of the negative electrode terminal are positioned so as to extend outside the exterior housing. A layer of resin of the same type or a different type from the resin used in the resin layer on the interior surface of the exterior housing can be provided in the areas where the positive electrode terminal and the negative electrode terminal contact the resin layer on the interior surface of the exterior housing.

[0076] The present invention is not limited to the above-described embodiment, and the present invention includes modifications and improvements within the scope of achieving the object of the present invention. [Example]

[0077] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0078] Example 1 An all-solid-state battery was fabricated by the following method.

[0079] [I] Preparation of anode-solid electrolyte layer stack (1) A foil (manufactured by Honjo Metals Co., Ltd.) was prepared as a negative electrode, in which a 20 μm thick metallic lithium layer was formed on the surface of a 10 μm thick stainless steel negative electrode current collector. (2) A slurry of Li6PS5Cl, a solid electrolyte, dispersed in xylene was applied to the surface of a polyester film whose main component was polyester, followed by drying to form a solid electrolyte layer on the polyester film. The solid electrolyte layer was then laminated on the negative electrode together with the polyester film so that the solid electrolyte layer was in contact with the surface of the metallic lithium layer of the negative electrode, yielding a negative electrode-solid electrolyte layer laminate. (3) The anode-solid electrolyte layer laminate obtained in (2) above was vacuum-sealed using a vacuum laminator and held at room temperature (25°C) under a pressure of 300 MPa for 1 minute. The anode-solid electrolyte layer laminate was then removed from the vacuum laminator and compressed by isostatic pressing (CIP) to obtain an anode-solid electrolyte layer laminate with a porosity of 7%. The size of the anode-solid electrolyte layer laminate was 50 mm × 70 mm. (4) The polyester film was peeled off from the solid electrolyte layer to obtain a negative electrode-solid electrolyte layer laminate.

[0080] [II] Lamination of positive electrode and negative electrode-solid electrolyte layer laminate (1) A slurry was obtained by dispersing the positive electrode active material, solid electrolyte, conductive additive, and binder in butyl butyrate at the ratios (mass%) shown in Table 1. The obtained slurry was then applied to an aluminum foil with a thickness of 10 μm and dried to form a positive electrode active material layer, thereby obtaining a positive electrode. (2) The cathode obtained in (1) above was cut to a size of 45 mm x 65 mm, and the cathode and the anode-solid electrolyte layer laminate prepared in [I] above were laminated together so that the cathode active material layer was in contact with the solid electrolyte layer of the anode-solid electrolyte layer laminate to obtain an electrode laminate precursor. The number of layers of the cathode and anode-solid electrolyte layer laminate was one each.

[0081] [III] Preparation of electrode stack The electrode laminate precursor obtained in [II] above was vacuum sealed using a vacuum laminator and held at room temperature (25°C) under a pressure of 300 MPa for 1 minute. The electrode laminate precursor was then removed from the vacuum laminator and compressed by a CIP method to obtain an electrode laminate with a porosity of 5% in the positive electrode active material layer.

[0082] [IV] Encapsulation in an outer packaging The electrode laminate obtained in [III] above was enclosed in an aluminum exterior body (manufactured by Dai Nippon Printing Co., Ltd.) by the method described in the embodiment, and an all-solid-state battery in which the positive electrode terminal and the negative electrode terminal were extended to the outside of the exterior body was obtained.

[0083] <Evaluation of battery characteristics> The all-solid-state battery obtained by the above method was evaluated by charging and discharging under the following conditions. First, the all-solid-state battery was charged at a constant current up to 4.25 V at a charge rate of 0.05 C, then switched to constant voltage charging, and charging was cut off at 0.005 C. Next, it was discharged at a constant current down to 2.5 V at a discharge rate of 0.05 C. The initial discharge capacity was calculated from the above charge and discharge, and the obtained initial discharge capacity was defined as the initial capacity (mAh). In addition, a tester was applied to the positive and negative electrode terminals of the charged all-solid-state battery, and the DC resistance between the positive and negative electrodes was measured at room temperature (25°C). The results obtained are shown in Table 1.

[0084] (Examples 2 to 8, Comparative Examples 1 to 3) All-solid-state batteries were fabricated and their battery characteristics were evaluated in the same manner as in Example 1, except that the types and ratios (mass%) of the positive electrode active material, solid electrolyte, conductive additive, and binder in the positive electrode active material were changed to those shown in Table 1. The results obtained are shown in Table 1.

[0085] [Table 1]

[0086] The resistance value ratio in Table 1 means the resistance value when the DC resistance value of the all-solid-state battery in Example 1 after full charge is set to 1.00. The SC / PC blending ratio means the mass ratio of the single crystal particles (SC) to the polycrystalline particles (PC).

[0087] Details of each component in Table 1 are as follows: <Cathode active material> LiNi 0.8 Co 0.1 Mn 0.1 O2 single crystal particles (average particle diameter d 50 : 4 μm, MSE Supplies) LiNi 0.8 Co 0.1 Mn 0.1O2 polycrystalline particles (average particle diameter d 50 : 4 μm, manufactured by MSE Supplies) LiNi 0.9 Co 0.05 Mn 0.05 O2 single crystal particles (average particle diameter d 50 : 4 μm, manufactured by MSE Supplies)

[0088] <Solid electrolyte> Li6PS5Cl (average particle size d 50 : 1 μm, manufactured by NEI) <Binder> VdF+HFP (copolymer of vinylidene fluoride and hexafluoropropylene, molecular weight: approximately 300,000, polymer composition: VdF 75 mol % and HFP 25 mol % of the entire polymer) PAA (polyacrylic acid, molecular weight: 450,000, manufactured by Sigma-Aldrich Japan) SBR (styrene-butadiene rubber, manufactured by Zeon Corporation) <Conductive additive> CB (carbon black, manufactured by Imerys) [Explanation of symbols]

[0089] 1 Cathode active material layer 2 Negative electrode active material layer 3 Positive electrode current collector 4 Negative electrode current collector 5 Solid electrolyte layer 6. Exterior body 7. Exterior body 8 Negative terminal 9 Positive terminal 10 All-solid-state battery

Claims

1. a positive electrode including a positive electrode active material layer including a positive electrode active material, a positive electrode binder, and a solid electrolyte; a solid electrolyte layer; a negative electrode including a negative electrode active material layer; Including, the positive electrode active material contains single-crystal particles (A) composed of a lithium-nickel-cobalt-manganese composite oxide, The positive electrode binder comprises a fluorine-based elastomer (B).

2. 2. The all-solid-state battery according to claim 1, wherein the lithium-nickel-cobalt-manganese composite oxide includes a composite oxide represented by the following formula (1): Li ａ Ni ｂ Co ｃ Mn ｄ M ｅ O ２ (1) (In the formula (1), M represents one or more elements selected from the group consisting of Al, Mg, Na, Co, K, W, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 0.5≦a≦1.5, 0.6≦b<1.0, 0<c<0.2, 0<d<0.2, 0≦e<1.0)

3. 3. The all-solid-state battery according to claim 1, wherein a content of the single-crystal particles (A) in the positive electrode active material is 50 parts by mass or more and 100 parts by mass or less, relative to 100 parts by mass of a content of the positive electrode active material in the positive electrode active material layer.

4. The average particle diameter d of the positive electrode active material in the volume-based particle size distribution measured by a laser diffraction scattering particle size distribution measurement method ５０ The all-solid-state battery according to any one of claims 1 to 3, wherein the average particle size is 0.1 µm or more and 30 µm or less.

5. The all-solid-state battery according to any one of claims 1 to 4, wherein the fluorine-based elastomer (B) contains a structural unit derived from vinylidene fluoride (VdF).

6. The all-solid-state battery according to claim 5, wherein the fluorine-based elastomer (B) further contains one or more structural units selected from the group consisting of structural units derived from hexafluoropropylene (HFP), structural units derived from trifluoropropylene (TFP), structural units derived from tetrafluoroethylene (TFE), structural units derived from 2,3,3,3-tetrafluoropropylene, structural units derived from 1,3,3,3-tetrafluoropropylene, and structural units derived from perfluoroalkyl vinyl ether (PAVE).

7. The all-solid-state battery according to any one of claims 1 to 6, wherein the fluorine-based elastomer (B) comprises one or more selected from the group consisting of a copolymer of vinylidene fluoride (VdF) and hexafluoropropylene (HFP) and a copolymer of vinylidene fluoride (VdF) and trifluoropropylene (TFP).

8. 8. The all-solid-state battery according to claim 1, wherein the content of structural units derived from vinylidene fluoride (VdF) in the fluorine-based elastomer (B) is 20 mol% or more.

9. The all-solid-state battery according to any one of claims 1 to 8, wherein the mass average molecular weight (Mw) of the fluorine-based elastomer (B) is 10,000 or more and 10,000,000 or less.

10. 10. The all-solid-state battery according to claim 1, wherein the content of the positive electrode binder in the positive electrode active material layer is 0.5 parts by mass or more and 8.0 parts by mass or less when the entire positive electrode active material layer is taken as 100 parts by mass.

11. The all-solid-state battery according to any one of claims 1 to 10, wherein the content of the positive electrode active material in the positive electrode active material layer is 50.0 parts by mass or more and 90.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

12. The all-solid-state battery according to any one of claims 1 to 11, wherein the solid electrolyte in the positive electrode active material layer comprises one or more selected from the group consisting of a sulfide-based solid electrolyte, an oxide-based solid electrolyte, and a polymer-based solid electrolyte.

13. The all-solid-state battery according to any one of claims 1 to 12, wherein the content of the solid electrolyte in the positive electrode active material layer is 5.0 parts by mass or more and 40.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

14. The all-solid-state battery according to any one of claims 1 to 13, wherein the positive electrode active material layer further contains a conductive additive.

15. 15. The all-solid-state battery according to claim 14, wherein the conductive additive comprises one or more selected from the group consisting of carbon black, activated carbon, graphite, mesoporous carbon, fullerenes, carbon nanotubes, carbon nanofibers, and carbon brushes.

16. 16. The all-solid-state battery according to claim 14, wherein a content of the conductive additive in the positive electrode active material layer is 0.1 parts by mass or more and 10.0 parts by mass or less, when the entire positive electrode active material layer is taken as 100 parts by mass.

Images