Negative electrode for all-solid-state battery and all-solid-state battery including same

Abstract

The present invention relates to a negative electrode for an all-solid-state battery and an all-solid-state battery including same, the negative electrode for an all-solid-state battery including: a current collector; a negative electrode coating layer positioned on the current collector; and a binder layer continuously or discontinuously positioned along the boundary of the current collector.

Description

Anode for an all-solid-state battery and an all-solid-state battery comprising the same

[0001] The present invention relates to a cathode for an all-solid-state battery and an all-solid-state battery including the same.

[0002] Recently, rapid developments have been made in electronic devices that use batteries, such as cell phones, laptop computers, and electric vehicles.

[0003] Lithium-ion secondary batteries are primarily used for these types of batteries, and currently commercialized lithium-ion secondary batteries use graphite, silicon, or a combination of these as their anode active materials. However, despite the growing demand for higher energy densities, lithium secondary batteries using graphite, silicon, or a combination of these as anode active materials cannot meet this demand. Furthermore, safety issues are emerging regarding lithium secondary batteries.

[0004] Accordingly, the development of all-solid-state batteries using lithium metal as the cathode is underway. All-solid-state batteries are composed entirely of solid materials, specifically those using solid electrolytes. Because lithium metal has a large potential difference with the anode, it boasts a high average voltage and a theoretical capacity of approximately 3,860 mAh / g, enabling high energy density. Furthermore, solid electrolytes offer improved safety due to their reduced risk of fire.

[0005] One embodiment provides a cathode for an all-solid-state battery having excellent safety.

[0006] Another embodiment provides an all-solid-state battery comprising the above negative electrode.

[0007] One embodiment provides an anode for an all-solid-state battery, comprising a current collector, a cathode coating layer positioned on the current collector, and a binder layer positioned continuously or discontinuously along an edge of the current collector.

[0008] Another embodiment provides an all-solid-state battery comprising the cathode and the anode and a solid electrolyte layer positioned between the cathode and the anode.

[0009] According to one embodiment, an anode for an all-solid-state battery can maintain excellent bonding strength between the anode coating layer and the current collector while reducing the binder content included in the anode coating layer.

[0010] Figure 1 is a schematic drawing of an all-solid-state battery negative electrode according to one embodiment.

[0011] Figure 2a is a drawing showing a plan view of a negative electrode for an all-solid-state battery according to one embodiment.

[0012] Figure 2b is a drawing showing a plan view of a negative electrode for an all-solid-state battery according to another embodiment.

[0013] Figure 2c is a drawing showing a plan view of a cathode for an all-solid-state battery according to another embodiment.

[0014] Figure 3 is a schematic drawing of an all-solid-state battery negative electrode according to another embodiment.

[0015] Figure 4 is a cross-sectional view schematically showing an all-solid-state battery according to one embodiment.

[0016] Figure 5 is a cross-sectional view schematically showing an all-solid-state battery according to another embodiment.

[0017] Figure 6 is a photograph of the cathode after performing the warm isotropic pressure process of Example 1.

[0018] Figure 7 is a photograph of the cathode after performing the warm isotropic pressure process of Comparative Example 2.

[0019] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0020] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0021] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0022] It should be understood that terms such as "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0023] Throughout this specification, when it is said that a part "includes" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0024] In addition, the terms "about", "substantially", etc. used throughout this specification are used in the sense of numerical values ​​or near numerical values ​​when manufacturing and material tolerances inherent to the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures that mention exact or absolute values ​​to aid understanding of this specification.

[0025] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0026] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there are other parts in between.

[0027] In the present invention, "particle size" or "particle diameter" may be an average particle diameter. In addition, the average particle diameter may be defined as the average particle diameter (D50) based on 50% of the cumulative volume in a particle diameter distribution curve. The particle diameter may be measured by a method widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope, a scanning electron microscope, or a field emission scanning electron microscope (FE-SEM). Alternatively, the average particle diameter (D50) may be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from this. Alternatively, the average particle diameter (D50) may be measured using a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle diameter (D50) based on 50% of the particle diameter distribution in the measuring device can be calculated.

[0028] "Thickness" may be measured, for example, from photographs taken with an optical microscope such as a scanning electron microscope.

[0029] One embodiment relates to a cathode for an all-solid-state battery including a cathode coating layer.

[0030] In one embodiment, the negative electrode coating layer refers to a layer that helps lithium ions released from the positive electrode active material during charge / discharge of an all-solid-state battery to move toward the negative electrode and be deposited on the surface of the current collector. That is, a lithium deposition layer is formed between the current collector and the negative electrode coating layer due to the deposition of lithium ions, and the lithium deposition layer functions as the negative electrode active material. Such a negative electrode is generally referred to as a deposition-type negative electrode. The metal and carbon-based materials included in the negative electrode coating layer do not function as negative electrode active materials that directly participate in charge / discharge reactions. Such a deposition-type negative electrode refers to a negative electrode that does not include a negative electrode active material when the battery is assembled, but in which the lithium deposition layer functions as the negative electrode active material. More specifically, when the all-solid-state battery is charged, lithium ions are released from the positive electrode active material, pass through the solid electrolyte, move toward the negative electrode, and are deposited on the negative electrode current collector, resulting in the formation of a lithium deposition layer between the negative electrode current collector and the negative electrode coating layer.

[0031] The above-mentioned negative electrode for an all-solid-state battery includes a current collector, a negative electrode coating layer positioned on the current collector, and a binder layer.

[0032] In one embodiment, the binder layer is positioned continuously or discontinuously along the edge of the current collector. Such a negative electrode is one in which the negative electrode coating layer and the binder layer are positioned separately on the current collector. That is, the binder layer and the negative electrode coating layer may exist separately.

[0033] In one embodiment, the edge of the current collector does not mean a side surface of the current collector, but rather an edge on the current collector. Accordingly, the binder layer may be positioned on the same surface as the negative electrode coating layer on the current collector.

[0034] A binder layer present at the edge of the current collector, separate from the negative electrode coating layer, can hold the negative electrode coating layer well. For example, since the binder layer holds both the negative electrode coating layer and the current collector, even if the negative electrode coating layer is detached from the current collector when pressurized during the negative electrode manufacturing process, the binder layer can act as a bridge that holds it from the side. Therefore, even if the binder content included in the negative electrode coating layer is reduced, the negative electrode coating layer can be prevented from being detached from the current collector.

[0035] In this way, when the binder content included in the negative electrode coating layer is reduced, the lithium precipitation layer formed by deposition on the current collector during charging of the all-solid-state battery can be formed more effectively. This is because the binder acts as a resistor, and thus, when the binder content is reduced, the resistance can be reduced, making it easier for lithium ions to pass through the negative electrode coating layer.

[0036] In general, a decrease in the binder content contained within the cathode coating layer may cause the cathode coating layer to detach from the current collector during the all-solid-state battery manufacturing process, especially during the pressurization process.

[0037] In this regard, as described above, the negative electrode according to one embodiment forms a binder layer at the edge of the current collector, thereby improving the bonding strength between the substrate and the negative electrode coating layer by acting as a bridge between the substrate and the negative electrode coating layer, thereby preventing the negative electrode coating layer from being detached from the current collector.

[0038] In addition, if the binder layer is formed to cover the entire current collector, the binder layer and the current collector are combined, so lithium deposition does not occur between the current collector and the negative electrode coating layer, but occurs between the binder layer and the negative electrode coating layer, which may cause the negative electrode coating layer to tear, and the resistance within the negative electrode may increase due to an increase in the binder content, so that lithium deposition and desorption may not occur well.

[0039] In one embodiment, the height of the binder layer may be the same as the height of the negative electrode coating layer. For example, the binder layer may include a first surface in contact with the current collector and a second surface opposite the first surface, and a solid electrolyte layer may cover the second surface. Referring to Fig. 1, which is a cross-sectional view schematically showing a negative electrode (1) according to one embodiment, the negative electrode includes a current collector (3), a negative electrode coating layer (5) positioned on the current collector (3), and a binder layer (7).

[0040] In this case, the binder layer (7) may be positioned continuously at the edge of the current collector (not shown) and may be positioned surrounding the negative electrode coating layer (5), as shown in Fig. 2(a) which shows a plan view of the negative electrode (1). In another embodiment, as shown in Figs. 2(b) and 2(c), the binder layer (7) may be positioned discontinuously at the edge of the current collector, that is, may be positioned only at the corner, that is, at the corner of the negative electrode coating layer (5), or may be positioned not only at the corner but also at the center with a certain distance between the two corners.

[0041] In another embodiment, the height of the binder layer may be less than the height of the cathode coating layer. For example, the binder layer may include a first surface in contact with the current collector and a second surface opposite to the first surface, and the cathode coating layer may cover the second surface.

[0042] Referring to Fig. 3, which is a cross-sectional view schematically showing a cathode (1') according to another embodiment, the cathode includes a current collector (3'), a cathode coating layer (5') positioned on the current collector (3'), and a binder layer (7').

[0043] In this case, the thickness of the binder layer may be 5% to 70% of the 100% thickness of the cathode coating layer, and may also be 10% to 70% of the 100% thickness of the cathode coating layer. At this time, the 100% thickness of the cathode coating layer means the thickness of the center of the cathode coating layer. When the thickness of the binder layer is included in the above range, the contact area with the cathode coating layer increases, so that the bonding force can be further increased, and the cathode reaction can also occur in this area, so that the N / P ratio (cathode / anode capacity ratio) can be more appropriately controlled.

[0044] For example, the ratio of the height of the cathode coating layer to the height of the binder layer may be 1:0.05 to 1:0.7, or may be 1:0.1 to 1:0.5.

[0045] When the thickness of the binder layer and the ratio of the height of the cathode coating layer to the height of the binder layer are within the above range, the bonding force between the binder layer and the cathode coating layer can be further increased, the contact area with the combined layer can be increased, so that the bonding force can be further increased, and the N / P ratio (capacity ratio of the cathode / anode) can be more appropriately controlled.

[0046] Even if the binder layer is positioned at the same height as the negative electrode coating layer or at a height smaller than the negative electrode coating layer, the width of the binder layer may be 0.5 mm or more and 10 mm or less, or 1 mm or more and 5 mm. When the width of the binder layer is within the above range, the bonding force between the substrate and the negative electrode coating layer can be more stably provided, and the utilization rate of the negative electrode can be further increased. In addition, when the binder layer is positioned continuously along the edge of the current collector, the edge portion of the current collector can be prevented from reacting, thereby effectively suppressing the occurrence of a short circuit during battery operation.

[0047] In one embodiment, the binder in the binder layer may be any binder commonly used in lithium secondary batteries. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0048] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0049] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0050] Additionally, a cellulose-based compound may be used as a binder, and such a cellulose-based compound may be used together with the aqueous binder. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0051] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0052] The above cathode coating layer may include a metal, a carbon-based material, and a cathode binder. At this time, the content of the cathode binder may be 1 wt% to 9 wt%, 1 wt% to 6.6 wt%, or 1 wt% to 4 wt% with respect to 100 wt% of the total cathode coating layer. As such, the binder content of the cathode coating layer according to one embodiment is a smaller content than the binder content of about 11 wt% included in a conventional cathode coating layer.

[0053] According to one embodiment, the cathode can reduce the binder content of the cathode coating layer by including a binder layer positioned at the edge of the current collector separately from the cathode coating layer.

[0054] As in one embodiment, when a separate binder layer is not included and the binder content of the negative electrode coating layer is less than 11 wt%, the negative electrode coating layer is detached from the current collector during battery manufacturing, which is not suitable.

[0055] In the above cathode coating layer, for example, a metal may be supported on a carbon-based material, or a metal and a carbon-based material may be present in a mixture.

[0056] When a metal is supported on a carbon-based material, it can be obtained by performing a support process of mixing a metal compound and a reducing agent. The metal compound can be a metal nitride, a metal sulfate, a metal perchlorate, or a combination thereof. For example, when the metal is Ag, it can be AgNO3, Ag2SO4, AgClO4, or a combination thereof. The reducing agent can be NaBH4, ascorbic acid, trisodium citrate, ethylene glycol, or a combination thereof.

[0057] The carbonaceous material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof, and may be amorphous carbon. The crystalline carbon may be, for example, amorphous, plate-shaped, flake-shaped, spherical, or fibrous natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, graphene, or a combination thereof. An example of the carbon black is Super P (Timcal). The amorphous carbon is not limited thereto, and any material classified as amorphous carbon in the relevant field may be used.

[0058] In one embodiment, the carbonaceous material may be a single particle, or may be an assembly having a secondary particle form in which primary particles are assembled. When the carbonaceous material is a single particle, the size of the carbonaceous material may be a nano-size with an average particle diameter of 100 nm or less, for example, 10 nm to 100 nm.

[0059] Additionally, when the carbon-based material is an assembly, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0060] In one embodiment, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and may be 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0061] In one embodiment, the particle size of the secondary particles may be 1 µm or more, 3 µm or more, 5 µm or more, 7 µm or more, 10 µm or more, or 15 µm or more, and may be 20 µm or less, 15 µm or less, 10 µm or less, 7 µm or less, 5 µm or less, or 3 µm or less.

[0062] The shape of the primary particles may be spherical, elliptical, plate-shaped, or a combination thereof, and in one embodiment, the shape of the primary particles may be spherical, elliptical, or a combination thereof.

[0063] The metal acts as a catalyst and may be, for example, Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, Si, or a combination thereof, or an alloy thereof. In one embodiment, the metal may be Ag. Since the cathode coating layer includes the metal, the electrical conductivity of the cathode can be further improved.

[0064] The metal may be a nanoparticle, and the size of the metal nanoparticle may be, for example, an average size of 5 nm to 80 nm, but a nanometer size may be suitably used. By using the metal nanoparticle having such a nano size, the battery characteristics (e.g., life characteristics) of the all-solid-state battery can be improved. If the metal particle size increases to the micrometer level, the uniformity of the metal particles in the negative electrode coating layer decreases, so that the current density in a specific region increases and the cycle life characteristics may deteriorate, which is not suitable.

[0065] In the above cathode coating layer, the mixing ratio of the metal and the carbon-based material may be, for example, a weight ratio of 1:10 to 1:0.5. In this case, the precipitation of lithium metal can be promoted more effectively and the characteristics of the all-solid-state secondary battery can be improved.

[0066] The above-described cathode coating layer may further include additives such as fillers and dispersants. In addition, known materials generally used in all-solid-state batteries may be used as fillers, dispersants, etc. that can be included in the cathode coating layer.

[0067] The thickness of the cathode coating layer may be 1 µm to 20 µm. For example, the thickness of the cathode coating layer may be 1 µm or more, 3 µm or more, 5 µm or more, 20 µm or less, 18 µm or less, 16 µm or less, 14 µm or less, 12 µm or less, or 10 µm or less.

[0068] The above cathode binder may be a non-aqueous binder.

[0069] The non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or a combination thereof.

[0070] The current collector may be, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0071] The current collector may be formed of the metal as a substrate and may further include a thin film formed on the substrate. The thin film may include an element capable of forming an alloy with lithium, and may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, or a combination thereof, but is not limited thereto, and any element capable of forming an alloy with lithium in the art may be used. When the current collector further includes a thin film, when the lithium-containing layer is formed by precipitation during charging, a more planarized lithium-containing layer may be formed, thereby further improving the cycle life of the all-solid-state battery.

[0072] The thickness of the above thin film may be 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. When the thin film thickness is within the above range, the cycle life characteristics can be further improved.

[0073] The cathode according to one embodiment can be manufactured by the following process, but is not limited thereto, and it goes without saying that any method can be used to manufacture the cathode having the binder layer and cathode coating layer configuration according to one embodiment.

[0074] The binder layer composition is coated continuously or discontinuously along the edge of the current collector and dried to form a binder layer.

[0075] The above binder layer composition includes a binder and a solvent. The binder is as described above. The solvent may be water or an organic solvent. The organic solvent may be N-methyl pyrrolidone, octyl acetate, diethyl carbonate, pentyl propionate, or a combination thereof. The solvent is not limited thereto, and any solvent capable of dissolving the binder may be used. The content of the binder may be 4 wt% to 50 wt%, or 4 wt% to 25 wt%, based on 100 wt% of the total binder layer composition. The viscosity of the binder layer composition may be 500 cps to 3,000 cps, or 750 cps to 2,000 cps at room temperature (20°C to 25°C). The binder content may be appropriately adjusted so as to obtain the viscosity of the binder layer composition.

[0076] The process of coating the above binder layer composition can be performed by pattern coating. The pattern coating can be performed, for example, by gravure coating the binder layer composition onto a current collector using a gravure coater, or can be performed using a mask film. The method of using a mask film can be performed by attaching a patterned mask film onto a current collector, coating the binder layer composition, and then removing the mask film. When using a mask film, a general coater such as a slot die or a 3-roll reverse comma coater can be used.

[0077] In this process, the binder layer composition coating thickness can be controlled to form a binder layer with the same thickness as the cathode coating layer, or the binder layer can be formed lower than the cathode coating layer.

[0078] The above drying process can be performed at 60°C to 120°C.

[0079] Next, a negative electrode coating layer composition is coated on the current collector and dried to form a negative electrode coating layer. The negative electrode coating layer composition includes a metal, a carbon-based material, a binder, and a solvent. The carbon-based material may be the amorphous carbon or crystalline carbon described above. The metal may be the metal described above, and the binder may be the binder described above.

[0080] The contents of the above metal, the above carbon-based material, and the above binder can be adjusted to be the above-described contents contained in the cathode coating layer.

[0081] The solvent may be N-methylpyrrolidone (NMP) solvent, benzene, hexane, tetrahydrofuran (THF), ethanol, isopropyl alcohol (IPA), dimethyl sulfoxide, dimethylformamide, acrylonitrile, or a combination thereof.

[0082] The method for coating the cathode coating layer composition can be performed using a conventional coating process such as spray coating or gravure coating.

[0083] When the binder layer is lower than the cathode coating layer, the coating process may be performed so that the cathode coating layer composition covers the upper portion of the binder layer, so that the cathode surface is substantially completely covered with the cathode coating layer.

[0084] The above drying process can be performed at 60°C to 120°C.

[0085] Another embodiment provides an all-solid-state battery comprising the cathode and also comprising a cathode, and a solid electrolyte layer positioned between the cathode and the anode.

[0086] According to one embodiment, the negative electrode may further include a lithium-containing layer formed during initial charging after battery manufacturing, between the current collector and the negative electrode coating layer. The thickness of the lithium-containing layer may be 1 µm to 1000 µm, 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 150 µm, 1 µm to 100 µm, or 1 µm to 50 µm. When the thickness of the lithium-containing layer is within the above range, the lithium storage function may be appropriately performed, and there may be an advantage of further improving the lifespan.

[0087] The lithium-containing layer can be formed when lithium ions are released from the positive electrode active material during charging after the battery is manufactured, pass through the solid electrolyte, and move toward the negative electrode, resulting in lithium being precipitated and deposited on the negative electrode current collector.

[0088] The above charging process may be a chemical reaction process performed once to three times at 0.05C to 1C at 25°C to 60°C. When lithium is precipitated and deposited to form a lithium-containing layer, the lithium contained in the lithium-containing layer is ionized and moves toward the positive electrode during discharge, so that the lithium can be used as an anode active material.

[0089] In one embodiment, since the lithium-containing layer is positioned between the current collector and the negative electrode coating layer, the negative electrode coating layer can serve as a protective layer for the lithium-containing layer, thereby inhibiting the precipitation and growth of lithium dendrites. This can suppress short-circuiting and capacity degradation of the all-solid-state battery, and consequently improve the cycle life of the all-solid-state battery.

[0090] The above solid electrolyte layer includes a solid electrolyte. The solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

[0091] In one embodiment, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m and n are integers greater than or equal to 0 and less than or equal to 12, respectively, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are integers greater than or equal to 0 and less than or equal to 12, respectively; M is one of P, Si, Ge, B, Al, Ga In), Li a M b P c S d A e (a, b, c, d and e are each integers greater than or equal to 0 and less than or equal to 12, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I). The sulfide-based solid electrolyte may be, for example, Li 7-x PS 6-x F x (0≤x≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) or Li 7-x PS 6-x I x (0≤x≤2) can be. Also, specifically, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li6.2 PS 5.2 Br 0.8 It could be the back.

[0092] In one embodiment, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The argyrodite-type sulfide-based solid electrolyte may be, for example, Li a M b P c S d A e (a, b, c, d and e are all 0 or more and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I), and specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li6PS5I, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0093] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixture thereof. For example, the sulfide-based solid electrolyte may be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3. Mechanical milling or a solution method can be applied as a mixing method. Mechanical milling is a method in which starting materials are placed in a reactor and vigorously stirred with a ball mill, etc. to pulverize the starting materials and mix them. When the solution method is used, the starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. In addition, additional calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte can become more solid.

[0094] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0095] The above oxide-based solid electrolyte is, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), Pb(Mg3Nb 2 / 3)O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr, x is an integer from 1 to 10), or a mixture thereof.

[0096] The above solid polymer electrolytes include, for example, polyethylene oxide, poly(diallyldimethylammonium)trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, Li3PO4·Li2S·SiS2, Li2S·GeS2·Ga2S3, Li2O·11Al2O3, Na2O·11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3(0.1≤x≤0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x (M,Al,Ga) x (Ge 1-y Ti y ) 2-x (PO4)3(x≤0.8, 0≤y≤1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), Li 1+x+y Q x Ti 2-x Si y P 3-y O 12 (0 <x≤0.4, 0<y≤0.6, Q는 Al 또는Ga), Li6BaLa2Ta2O 12 , Li7La3Zr2O 12 , Li5La3Nb2O 12 , Li5La3M2O 12 (M is Nb, Ta) and Li 7+x A x La 3-x Zr2O 12 (0 <x<3, A는 Zn) 중에서 선택된 하나 이상을 포함할 수 있다.

[0097] The above halide-based solid electrolyte may include a Li element, an M element (M is a metal other than Li), and an X element (X is a halogen). As X, for example, F, Cl, Br, and I may be mentioned. In particular, in the halide-based solid electrolyte, at least one of Br and Cl is suitable as X. In addition, as the M, for example, a metal element such as Sc, Y, B, Al, Ga, or In may be mentioned.

[0098] The composition of the above halide-based solid electrolyte is not particularly limited, but Li6-3a M a Br b Cl c (In the formula, M is a metal other than Li, and 0 <a<2, 0≤b≤6, 0≤c≤6, b+c=6)로 표현될 수 있다. 이때, 상기 a는 0.75 이상일 수 있고, 1 이상일 수 있고, a는, 1.5 이하일 수 있다. 상기 b는 1 이상일 수 있고, 2 이상일 수 있다. 또한, 상기 c는, 3 이상일 수 있고, 4 이상일 수도 있다. 상기 할라이드계 고체 전해질의 구체적인 예로는 Li3YBr6, Li3YCl6또는 Li3YBr2Cl4를 들 수 있다.

[0099] The above solid electrolyte is in the form of particles, and the average particle diameter (D50) may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.5 ㎛ to 5.0 ㎛, 0.5 ㎛ to 4.0 ㎛, 0.5 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.5 ㎛ to 1.0 ㎛.

[0100] The above solid electrolyte layer may further include a binder. At this time, the binder may be styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, but is not limited thereto, and any binder used in the relevant technical field may be used. The acrylate polymer may be butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0101] The above solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the same on a base film, and drying the same. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. Since the solid electrolyte layer formation process is widely known in the art, a detailed description thereof will be omitted herein.

[0102] The above positive electrode includes a positive electrode current collector and a positive electrode active material layer positioned on one surface of the positive electrode current collector.

[0103] The above-mentioned positive electrode active material layer may include a positive electrode active material. The positive electrode active material may be a positive electrode active material capable of reversibly absorbing and releasing lithium ions. For example, the positive electrode active material may use at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof. Specific examples of the positive electrode active material include Li a A 1-b B 1 b D 1 2(0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b B 1 b O 2-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a E 2-b B 1 b O 4-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a Ni 1-b-c Co b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Co b B 1 c O 2-α F1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); The a Nor 1-b-c Mn b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); The a Nor 1-b-c Mn b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); The a Nor 1-b-c Mn b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); The a Nor b E c G d O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); The a Nor b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); The a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); The a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); The a MnG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); The a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI1 O2; LiNiVO4; Li (3-f) J2(PO4)3(0≤f≤2); Li (3-f) Fe2(PO4)3(0≤f≤2); or LiFePO4.

[0104] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1 is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0105] According to one implementation example, LiNi is used as the positive electrode active material. x Co y Al z O2(NCA), LiNi x Co y Mn z O2(NCM)(but, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1) 등의 삼성분계 리튬 전이 금속 산화물을 들 수 있다.

[0106] Of course, it is also possible to use a compound having a coating layer on the surface of the compound, or it is also possible to use a mixture of the compound and a compound having a coating layer. The coating layer may include at least one coating element compound selected from the group consisting of an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, and a hydroxycarbonate of the coating element. The compounds forming these coating layers may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer forming process may use any coating method as long as it can coat the compound with these elements in a method that does not adversely affect the properties of the positive electrode active material (for example, spray coating, dipping, etc.), and since this is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0107] In addition, as the above coating layer, any known coating layer of the positive electrode active material of an all-solid-state battery can be applied, and examples thereof include Li2O-ZrO2 (LZO).

[0108] Furthermore, when the cathode active material is a ternary compound containing nickel, cobalt, and manganese, or nickel, cobalt, and aluminum, the capacity density of the all-solid-state battery can be further improved and metal dissolution from the cathode active material can be further reduced in a charged state. Consequently, the all-solid-state battery can exhibit improved long-term reliability and cycle performance in a charged state.

[0109] Here, examples of the shape of the positive electrode active material include spherical, elliptical, and other particle shapes. Furthermore, the average particle diameter of the positive electrode active material is not particularly limited, and may be within the range applicable to positive electrode active materials for existing all-solid-state secondary batteries. Furthermore, the content of the positive electrode active material in the positive electrode active material layer is also not particularly limited, and may be within the range applicable to positive electrode layers for existing all-solid-state secondary batteries.

[0110] The positive electrode active material layer may additionally include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer may be the same as or different from the solid electrolyte included in the solid electrolyte layer. The solid electrolyte may be included in an amount of 10 wt% to 30 wt% based on the total weight of the positive electrode active material layer.

[0111] The above positive electrode current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet.

[0112] The above positive electrode active material layer may further include a binder and / or a conductive material.

[0113] The above binder may include, but is not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0114] The above binder may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer for the all-solid-state battery. Within the above content range, the binder can sufficiently exhibit adhesive ability without deteriorating battery performance.

[0115] The above conductive material is used to provide conductivity to the electrode, and in the battery to be constructed, any material that does not cause a chemical change and is electronically conductive can be used. Examples thereof include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nano fiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, and silver in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or a conductive material including a mixture thereof.

[0116] The conductive material may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer for the all-solid-state battery. Within the above content range, the conductive material may improve electrical conductivity without degrading battery performance.

[0117] The thickness of the positive electrode active material layer may be 90 μm to 200 μm. For example, the thickness of the positive electrode active material layer may be 90 μm or more, 100 μm or more, 110 μm or more, 120 μm or more, 130 μm or more, 140 μm or more, 150 μm or more, 160 μm or more, 170 μm or more, 180 μm or more, or 190 μm or more, and may be 200 μm or less, 190 μm or less, 180 μm or less, 170 μm or less, 160 μm or less, 150 μm or less, 140 μm or less, 130 μm or less, 120 μm or less, or 110 μm or less.

[0118] In one embodiment, the all-solid-state battery may further include a buffer material to cushion changes in thickness that occur during charging and discharging. The buffer material may be positioned between the negative electrode and the case, and in the case of a battery in which one or more electrode assemblies are stacked, the buffer material may be positioned between different electrode assemblies.

[0119] The above-mentioned cushioning material may be a material having an elastic recovery rate of 50% or more and an insulating function, and specifically, may be silicone rubber, acrylic rubber, fluorine rubber, nylon, synthetic rubber, or a combination thereof. The above-mentioned cushioning material may be in the form of a polymer sheet.

[0120] The above-mentioned all-solid-state secondary battery may be a unit cell having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode, or a laminated battery in which the structure of the unit cell is repeated.

[0121] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0122] FIG. 4 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 4, the all-solid-state battery (100) may have a structure in which an electrode assembly in which an anode (400) including an anode current collector (401), an anode coating layer (403), and a binder layer (402), a solid electrolyte layer (300), and a cathode (200) including a cathode active material layer (203) and a cathode current collector (201) are laminated is housed in a case such as a pouch. The all-solid-state battery (100) may further include an elastic layer (500) on the outer side of at least one of the cathode (200) and the anode (400). Although FIG. 4 illustrates one electrode assembly including an anode (400), a solid electrolyte layer (300), and a cathode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0123] Fig. 5 schematically illustrates an all-solid-state battery according to another embodiment. The all-solid-state battery (100) illustrated in Fig. 5 includes a positive electrode (200) including a positive electrode current collector (201) and a positive electrode active material layer (203), a negative electrode (400') including a negative electrode current collector (401'), a negative electrode coating layer (403') and a binder layer (402'), and a solid electrolyte (300) positioned between the positive electrode (200) and the negative electrode (400'), and includes a battery case (500) in which these are housed, and further includes a lithium precipitation layer (405') between the negative electrode current collector (401) and the negative electrode coating layer (403). When the all-solid-state battery is charged, the lithium precipitation layer can be formed by lithium ions being released from the positive electrode active material and deposited on the negative electrode current collector (401').

[0124] An all-solid-state battery according to one embodiment can be manufactured by a step of preparing a laminate by positioning a cathode, an anode, and a solid electrolyte layer between the cathode and the anode, and pressing the laminate.

[0125] The pressurizing process can be performed at a temperature ranging from 25°C to 90°C. In addition, the pressurizing process can be performed by pressurizing at a pressure of 550 MPa or less, for example, 500 MPa or less, for example, 1 MPa to 500 MPa. The pressurizing time can vary depending on the temperature and pressure, and can be, for example, less than 30 minutes. The pressurizing process can be, for example, isostatic pressing, roll pressing, plate pressing, or warm isostatic pressing (WIP).

[0126] Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0127] (Example 1)

[0128] (1) Manufacturing of cathode

[0129] A binder layer slurry was prepared by mixing 10 wt% of polyvinylidene fluoride binder and 90 wt% of N-methyl pyrrolidone solvent.

[0130] Carbon black (average particle size: 35 nm) and Ag (average particle size: 60 nm) were mixed in a weight ratio of 75:25, and the mixture was mixed with an N-methylpyrrolidone (NMP) solvent in which a polyvinylidene fluoride binder was dissolved to prepare a cathode coating layer slurry. The polyvinylidene fluoride binder content was 7 parts by weight based on 100 parts by weight of the carbon black and Ag mixture, and thus the binder content was approximately 6.5% by weight based on 100% by weight of the entire cathode coating layer.

[0131] The above binder layer slurry was coated along the edge of a stainless steel foil current collector (thickness: 10 μm) using a gravure coater so that the binder layer had a width of 1 mm. Subsequently, the coated current collector was dried at 80°C to form a binder layer having a thickness of 7 μm and a width of 1 mm. At this time, the binder layer was formed to be positioned continuously along the edge.

[0132] The obtained current collector was coated with the above-described negative electrode layer slurry and vacuum-dried at 80°C to form a 7 μm thick negative electrode coating layer. The manufactured negative electrode had a structure in which a binder layer was continuously formed at the edge of the current collector and a negative electrode coating layer was formed on the top of the current collector, as shown in Figs. 1 and 2a.

[0133] (2) Preparation of solid electrolyte layer

[0134] An isobutyl isobutylate binder solution (solid content: 50 wt%) containing butyl acrylate, an acrylate polymer, was added to an argyrodite-type solid electrolyte Li6PS5Cl and mixed. At this time, the mixing ratio of the solid electrolyte and the binder was set to a weight ratio of 98.7:1.3.

[0135] The above mixing process was performed using a sinky mixer. 2 mm zirconia balls were added to the resulting mixture and stirred again using the sinky mixer to produce a slurry. The slurry was cast onto a polytetrafluoroethylene film and dried at room temperature to produce a solid electrolyte with a solid electrolyte layer thickness of 100 μm.

[0136] (3) Manufacturing of anode

[0137] Cathode active material (LiNi) 0.9 Mn 0.05 Co 0.05A mixture was prepared by mixing O2), argyrodite-type solid electrolyte Li6PS5Cl, conductive carbon nanofibers, and binder polytetrafluoroethylene in a weight ratio of 85:15:3:1.5.

[0138] The prepared mixture was coated on an aluminum foil current collector and then vacuum-dried at 45°C to prepare a positive electrode including a 160 μm thick positive electrode active material layer and a 10 μm thick current collector.

[0139] (4) Manufacturing of all-solid-state full cells

[0140] An all-solid-state battery was manufactured by sequentially stacking the manufactured negative electrode, solid electrolyte, and positive electrode, and applying a pressure of 500 MPa through a warm isotropic pressing (WIP) process.

[0141] (Example 2)

[0142] A negative electrode was manufactured in the same manner as in Example 1, except that the binder layer slurry manufactured in Example 1 was continuously coated using a gravure coater so that a binder layer with a width of 1 mm was formed only on the edge corners of a stainless steel foil current collector (thickness: 10 ㎛), and the coated current collector was dried at 80°C to form a binder layer with a thickness of 7 ㎛ and a width of 1 mm. The manufactured negative electrode had a binder layer formed only on the edge corners of the current collector, as shown in FIGS. 1 and 2b.

[0143] (Example 3)

[0144] A binder layer slurry manufactured in the above Example 1 was continuously coated using a gravure coater so that a binder layer with a width of 1 mm was formed only at the edge corners and the center of the edge corners of a stainless steel foil current collector (thickness: 10 ㎛), and the coated current collector was dried at 80°C to form a binder layer with a thickness of 7 ㎛ and a width of 1 mm, except that the same procedure as in Example 1 was followed to manufacture a negative electrode. As shown in FIGS. 1 and 2c, the manufactured negative electrode had a binder layer formed at the edge corners of the edge of the current collector and the center between the edge corners.

[0145] (Example 4)

[0146] A negative electrode was manufactured in the same manner as in Example 1, except that the binder layer slurry manufactured in Example 1 was continuously coated along the edge of a stainless steel foil current collector (thickness: 10 ㎛) using a gravure coater so that the binder layer had a width of 1 mm, and dried at 80°C to form a binder layer having a thickness of 0.5 ㎛ and a width of 1 mm. The manufactured negative electrode had a structure in which a binder layer was continuously formed on the edge of the current collector, a negative electrode coating layer was formed on the upper portion of the current collector, and a second surface of the binder layer, which was opposite to the first surface in contact with the current collector, was covered with the negative electrode coating layer.

[0147] (Example 5)

[0148] A binder layer slurry manufactured in the above Example 1 was continuously coated along the edge of a stainless steel foil current collector (thickness: 10 ㎛) using a gravure coater so that the binder layer width was 1 mm, and dried at 80°C to form a binder layer with a thickness of 1 ㎛ and a width of 1 mm, except that the same procedure as in Example 1 was followed to manufacture a negative electrode.

[0149] An all-solid-state battery was manufactured in the same manner as in Example 1 using the above-mentioned negative electrode, the solid electrolyte of Example 1, and the above-mentioned positive electrode.

[0150] An all-solid-state battery was manufactured in the same manner as in Example 1 using the above-mentioned negative electrode, the solid electrolyte of Example 1, and the above-mentioned positive electrode.

[0151] (Example 6)

[0152] A negative electrode was manufactured in the same manner as in Example 1, except that the binder layer slurry manufactured in Example 1 was continuously coated along the edge of a stainless steel foil current collector (thickness: 10 ㎛) using a gravure coater so that the binder layer width was 1 mm, and dried at 80°C to form a binder layer with a thickness of 2 ㎛ and a width of 1 mm.

[0153] An all-solid-state battery was manufactured in the same manner as in Example 1 using the above-mentioned negative electrode, the solid electrolyte of Example 1, and the above-mentioned positive electrode.

[0154] (Comparative Example 1)

[0155] Carbon black (average particle size: 35 nm) and Ag (average particle size: 60 nm) were mixed in a weight ratio of 75:25, and the mixture was mixed with an N-methylpyrrolidone (NMP) solvent in which a polyvinylidene fluoride binder was dissolved to prepare a cathode coating layer slurry. The polyvinylidene fluoride binder content was 11 parts by weight based on 100 parts by weight of the carbon black and Ag mixture, and thus the binder content was approximately 10% by weight based on 100% by weight of the entire cathode coating layer.

[0156] The above cathode layer slurry was coated on a stainless steel foil current collector (thickness: 10 μm) and vacuum-dried at 80°C to manufacture a cathode having a cathode coating layer with a thickness of 7 μm.

[0157] An all-solid-state battery was manufactured in the same manner as in Example 1 using the above-mentioned negative electrode, the solid electrolyte of Example 1, and the above-mentioned positive electrode.

[0158] (Comparative Example 2)

[0159] Carbon black (average particle size: 35 nm) and Ag (average particle size: 60 nm) were mixed in a weight ratio of 75:25, and the mixture was mixed with an N-methylpyrrolidone (NMP) solvent in which a polyvinylidene fluoride binder was dissolved to prepare a cathode coating layer slurry. The polyvinylidene fluoride binder content was 7 parts by weight based on 100 parts by weight of the carbon black and Ag mixture, and thus the binder content was approximately 6.5% by weight based on 100% by weight of the entire cathode coating layer.

[0160] The above cathode layer slurry was coated on a stainless steel foil current collector (thickness: 10 μm) and vacuum-dried at 80°C to manufacture a cathode having a cathode coating layer with a thickness of 7 μm.

[0161] An all-solid-state battery was manufactured in the same manner as in Example 1 using the above-mentioned negative electrode, the solid electrolyte of Example 1, and the above-mentioned positive electrode.

[0162] (Comparative Example 3)

[0163] Carbon black (average particle size: 35 nm) and Ag (average particle size: 60 nm) were mixed in a weight ratio of 75:25, and the mixture was mixed with an N-methylpyrrolidone (NMP) solvent in which a polyvinylidene fluoride binder was dissolved to prepare a cathode coating layer slurry. The polyvinylidene fluoride binder content was 7 parts by weight based on 100 parts by weight of the carbon black and Ag mixture, and thus the binder content was approximately 6.5% by weight based on 100% by weight of the entire cathode coating layer.

[0164] The binder layer slurry manufactured in Example 1 was coated entirely on a stainless steel foil current collector (thickness: 10 μm), and then dried at 80°C to form a binder layer with a thickness of 0.5 μm.

[0165] The above-mentioned cathode layer slurry was coated on the above-mentioned binder layer, vacuum-dried at 80°C, and a cathode coating layer having a thickness of 7 μm was formed, thereby manufacturing a cathode in which a current collector, a binder layer, and a cathode coating layer were formed in sequence.

[0166] Experimental Example 1) Dropout Evaluation Photo

[0167] After performing the warm isotropic pressure process in the all-solid-state battery process according to Example 1 and Comparative Example 2, the negative electrode was separated. The surface photographs of the central portion of the negative electrode were measured, and the results are shown in Fig. 6 (Example 1) and Fig. 7 (Comparative Example 2), respectively.

[0168] As shown in Fig. 6, it can be seen that in Example 1, the cathode coating layer did not fall off, and as shown in Fig. 7, it can be seen that in Comparative Example 2, the cathode coating layer fell off and the current collector was exposed.

[0169] Experimental Example 2) Initial Efficiency Evaluation

[0170] For the all-solid-state batteries manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3, a 0.05C charge / discharge cycle was performed once to obtain the percentage value of the discharge capacity relative to the charge capacity. The results are presented as initial efficiency in Table 1 below.

[0171] Experimental Example 3) Output Efficiency Evaluation

[0172] The all-solid-state batteries manufactured according to Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to 0.1 C charging and 1.0 C discharging. The percentage value of the discharge capacity to the charge capacity was obtained, and the results are presented in Table 1 below as output efficiency.

[0173] Whether the cathode coating layer is peeled (peel off, not peeled off)Initial efficiency (%)Output efficiency (%)Example 1X86.789.7Example 2X86.588.2Example 3X86.889.2Example 4X87.091.3Example 5X86.991.8Example 6X86.790.8Comparative example 1X84.584.6Comparative example 2086.487.2Comparative example 3084.082.1

[0174]

[0175] As shown in Table 1 above, the all-solid-state batteries including the negative electrodes of Examples 1 to 6 showed excellent initial efficiency and output efficiency without negative electrode coating layer peeling. In Comparative Example 1, since an excessive amount of binder was used in the negative electrode coating layer, negative electrode coating layer peeling did not occur, but it can be seen that the initial efficiency and output efficiency were reduced. In addition, Comparative Example 2 showed excellent initial efficiency, but the output efficiency was somewhat reduced, and also the negative electrode coating layer peeled. In addition, in Comparative Example 3, although a binder layer was formed between the current collector and the negative electrode coating layer to cover the entire current collector, the negative electrode coating layer peeled, and deteriorated charging efficiency and output efficiency were shown.

[0176] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. Current collector; A cathode coating layer positioned on the current collector; and A binder layer positioned continuously or discontinuously along the edge of the above current collector. A cathode for an all-solid-state battery comprising:

2. In paragraph 1, An anode for an all-solid-state battery, wherein the binder layer is positioned on the same surface as the anode coating layer on the current collector.

3. In paragraph 1, The binder layer includes a first surface in contact with the current collector and a second surface opposite to the first surface, An all-solid-state battery negative electrode, wherein the negative electrode coating layer covers the second surface.

4. In paragraph 1, An anode for an all-solid-state battery, wherein the height of the binder layer is the same as the height of the cathode coating layer.

5. In paragraph 4, An all-solid-state battery negative electrode, wherein the binder layer is discontinuously positioned at the edge of the current collector.

6. In paragraph 1, An anode for an all-solid-state battery, wherein the height of the binder layer is smaller than the height of the cathode coating layer.

7. In paragraph 1, An anode for an all-solid-state battery, wherein the thickness of the binder layer is 5% to 70% of the thickness of the cathode coating layer of 100%.

8. In paragraph 1, An all-solid-state battery negative electrode having a ratio of the height of the negative electrode coating layer to the height of the binder layer of 1:0.05 to 1:0.

7.

9. In paragraph 1, An all-solid-state battery negative electrode, wherein the binder layer may have a width of 0.5 mm or more and 10 mm or less.

10. In paragraph 1, The above binder layer is a negative electrode for an all-solid-state battery, which is a non-aqueous binder, an aqueous binder, a dry binder or a combination thereof.

11. In paragraph 1, The above cathode coating layer includes a metal, a carbon-based material and a cathode binder, An all-solid-state battery negative electrode, wherein the content of the negative electrode binder is 1% to 9% by weight based on 100% by weight of the entire negative electrode coating layer.

12. In paragraph 11, An all-solid-state battery negative electrode having a content of the negative electrode binder of 1 to 6.6 wt% based on 100 wt% of the total negative electrode coating layer.

13. In paragraph 11, The above carbon-based material is an anode for an all-solid-state battery, which is amorphous carbon, crystalline carbon or a mixture thereof.

14. In paragraph 11, The above metal is an anode for an all-solid-state battery, which is Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, Si or a combination thereof.

15. In paragraph 11, The above negative electrode binder is a non-aqueous binder for an all-solid-state battery.

16. The cathode of any one of paragraphs 1 to 15; Bipolar; and A solid electrolyte layer positioned between the cathode and the anode An all-solid-state battery comprising:

17. In paragraph 16, The above solid electrolyte is an all-solid-state battery that is a sulfide-based solid electrolyte.

18. In paragraph 16, The above all-solid-state battery further includes a lithium-containing layer formed between the current collector and the negative electrode coating layer during initial charging.

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