Positive electrode, manufacturing method therefor, and all-solid-state battery comprising same

Abstract

The present invention relates to a positive electrode, a manufacturing method therefor, and an all-solid-state battery including same, wherein the positive electrode includes a positive electrode active material layer, the positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, and a binder, the binder includes a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder includes a thiol group. According to the present invention, it is possible to provide: the positive electrode having excellent adhesion between interfaces and / or between components in the positive electrode active material layer as well as excellent dispersibility, and having excellent high-rate discharge efficiency at 1.0C and capacity retention across cycles; a manufacturing method for the positive electrode; and an all-solid-state battery having excellent performance by including the positive electrode.

Description

Anode, method for manufacturing the same, and all-solid-state battery comprising the same

[0001] This application claims the benefit of priority from Republic of Korea Patent Application No. 2023-0180918, filed December 13, 2023, the entire disclosure of which is incorporated herein by reference. The present invention relates to a cathode, a method for manufacturing the same, and an all-solid-state battery comprising the same.

[0002] Customer demand for high-energy density and high-stability secondary batteries is rapidly increasing. To meet this demand, technological development for various all-solid-state battery electrodes is continuing. Among these, sulfide-based all-solid-state batteries, which offer high ionic conductivity and theoretically high energy density, are attracting significant attention.

[0003] In the sulfide-based all-solid-state battery system, lithium ion conduction does not occur through a liquid electrolyte as in the existing lithium-ion battery system, so a sulfide-based solid electrolyte with high ion conductivity is added during electrode manufacturing to improve lithium ion conductivity.

[0004] However, sulfide-based solid electrolytes are difficult to handle, as they can cause side reactions with polar solvents, posing significant limitations to their use. Therefore, continued research is needed to introduce sulfide-based solid electrolytes into electrodes to improve ionic conductivity and energy density, while also providing superior performance in electrodes and all-solid-state batteries.

[0005] The present invention is intended to solve the above problems, and one object of the present invention is to provide a positive electrode and a method for manufacturing the same, which have excellent dispersibility as well as excellent adhesiveness between interfaces and / or between components within a positive electrode active material layer, and excellent 1.0C high-rate discharge efficiency and capacity retention according to cycle.

[0006] Another object of the present invention is to provide an all-solid-state battery having excellent performance, including the positive electrode as described above.

[0007] One aspect of the present invention relates to a positive electrode comprising a positive electrode active material layer, wherein the positive electrode active material layer comprises a positive electrode active material, a sulfide-based solid electrolyte, and a binder, wherein the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and wherein the second binder comprises a thiol group.

[0008] In one embodiment, the weight ratio of the second binder to the first binder may be 0.1 to 10.

[0009] In one embodiment, the weight ratio of the thiol group in the second binder may be 0.05 to 5 wt%.

[0010] In one embodiment, the first binder and the second binder may be characterized in that each of the first binder and the second binder is at least one selected from the group consisting of styrene-butadiene rubber, acrylated styrene-butadiene rubber, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinylidene fluoride, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene, butadiene rubber, styrene-butadiene-styrene rubber, and styrene-panacene-styrene rubber.

[0011] In one embodiment, the binder may be included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the positive electrode active material.

[0012] In one embodiment, the sulfide-based solid electrolyte is Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-LiBr-LiI-P2S5, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-Li3PO4, Li2S-SiS2- Li p MO q (p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, and In), Li2S-SiS2-P2S5-LiI, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers), Z is one of Ge, Zn or Ga, L i2 S-GeS2, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x It can be characterized by being at least one selected from the group including (0≤x≤2).

[0013] In one embodiment, the positive electrode active material layer may be characterized by further including a conductive material.

[0014] In one embodiment, the particle size distribution analysis result for the positive electrode active material layer is D 95 It can be characterized by being 15 ㎛ or less.

[0015] In one embodiment, the particle size distribution analysis result for the positive electrode active material layer is D 90 / D 10 It can be characterized by 8 to 12.

[0016] In one embodiment, the particle size distribution analysis result for the positive electrode active material layer is (D 90 -D50 ) / (D 50 -D 10 ) can be characterized as being 0.7 to 1.3.

[0017] In one embodiment, the particle size distribution analysis result for the positive electrode active material layer is (D 95 -D 10 ) / D 50 This can be characterized as being 1.8 to 2.4.

[0018] In one embodiment, the positive electrode may be characterized by an adhesive strength of 30 gf / cm or more.

[0019] Another aspect of the present invention relates to a method for producing a positive electrode, comprising the steps of: preparing a positive electrode slurry by mixing a positive electrode active material, a sulfide-based solid electrolyte, and a binder in a non-polar solvent; applying the positive electrode slurry onto a positive electrode current collector; and drying; wherein the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and wherein the second binder comprises a thiol group.

[0020] In one embodiment, the drying step may be characterized in that it is performed at 70 to 130° C. in an atmospheric environment for 4 to 20 hours.

[0021] Another aspect of the present invention relates to an all-solid-state battery comprising a positive electrode and a solid electrolyte layer, wherein the positive electrode comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, a solid electrolyte, and a binder, the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder comprises a thiol group.

[0022] According to the present invention, a positive electrode and a method for manufacturing the same can be provided that exhibit excellent dispersibility, interfacial adhesion between components and / or within the positive electrode active material layer, and excellent 1.0C high-rate discharge efficiency and cycle-dependent capacity retention. Furthermore, the present invention can provide an all-solid-state battery having excellent performance, including the positive electrode as described above.

[0023] Figure 1 is a graph showing the capacity retention rate according to the discharge rate of the batteries of the examples and comparative examples.

[0024] Figure 2 is a graph showing the capacity retention rate according to the cycle of the batteries of the examples and comparative examples.

[0025] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0026] Accordingly, the configuration of the embodiments described in this specification is only one of the most preferred embodiments of the present invention and does not represent all of the technical ideas of the present invention, so it should be understood that various equivalents and modified examples that can replace them may exist at the time of filing this application.

[0027] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0028] When a part in this specification is said to “comprise” a certain component, this does not exclude other components unless specifically stated to the contrary, but rather means that other components may be included. Thus, for example, a composition comprising compound A may include compounds other than A. However, the term “comprise” also encompasses, as a specific embodiment thereof, the more restrictive meanings of “consisting essentially / essentially of” and “consisting of,” so that, for example, “a composition comprising compound A” may also consist (essentially / essentially) of compound A.

[0029] In this connection, it should be understood that terms such as “have” or “have” as used herein 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.

[0030] When it is said in this specification that any layer is located “on” or “between” any other layer, this includes not only cases where any layer is in contact with any other layer, but also cases where another layer or material, etc., exists between the two layers.

[0031] Where an amount, concentration, or other value or parameter is given herein as a range, a preferred range, or an enumeration of an upper preferred value and a lower preferred value, this should be understood to specifically disclose any range that can be formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the range is separately disclosed. Where a range of numerical values ​​is recited herein, unless otherwise stated, e.g., there is no limiting term such as greater than, less than, etc., the range is intended to include the endpoint values ​​and all integers and fractions within the range. The scope of the present invention is not intended to be limited to the specific values ​​recited when defining a range.

[0032] Among the properties mentioned in this specification, if the measurement temperature affects the property, the property is measured at room temperature unless otherwise specified. The term "room temperature" refers to the natural temperature without heating or cooling, and may mean, for example, any temperature within the range of about 10°C to 30°C, or about 23°C or about 25°C. In addition, unless otherwise specified, the unit of temperature in this specification is ℃.

[0033] In addition, among the properties mentioned in this specification, if the measurement pressure affects the property, the property is measured at normal pressure, i.e., atmospheric pressure (approximately 1 atm), unless otherwise specified.

[0034] In this specification, “all-solid-state battery” may mean an all-solid-state secondary battery, and may also be referred to as a cell, secondary battery, or battery.

[0035] A first aspect of the present invention relates to an anode.

[0036] The present invention relates to a positive electrode including a positive electrode active material layer, wherein the positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, and a binder, and the binder includes a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder is characterized in that it includes a thiol group.

[0037] Sulfide-based solid electrolytes are attracting attention because they offer high ionic conductivity and theoretically high energy density. Sulfide-based solid electrolytes, when used with polar solvents such as NMP, which are typically used in wet processes for lithium-ion batteries, can cause side reactions due to nucleophilic attack. Therefore, a dry process that does not use solvents has been proposed for preparing a slurry for the cathode active material layer. However, the dry process has limitations in sufficiently dispersing particles within the cathode active material layer, and it has also been difficult to form a cathode active material layer with a uniform thickness on the current collector. Considering the use of a wet process but using a nonpolar solvent that does not cause side reactions with the sulfide-based solid electrolyte, binders that dissolve in nonpolar solvents have problems such as insufficient adhesive strength or reduced dispersibility in relation to the sulfide-based solid electrolyte. Accordingly, in a positive electrode including a sulfide-based solid electrolyte, it is necessary to introduce a binder that can be suitably used in a wet process using a non-polar solvent, while at the same time improving the dispersibility of the positive electrode active material layer and having excellent binding strength, interfacial adhesion, and flexibility.

[0038] The present invention was designed to solve this problem, and it was confirmed that this purpose can be achieved by including two or more types of binders with different properties in the anode and combining them with other components.

[0039] The cathode active material layer of the present invention may be characterized by including, for example, a first binder and a second binder as binders.

[0040] The term first binder herein may also be referred to as a long-chain binder. The weight average molecular weight of the first binder may be, in other examples, 320,000 g / mol or more, 340,000 g / mol or more, 360,000 g / mol or more, 380,000 g / mol or more, 400,000 g / mol or more, 420,000 g / mol or more, or 440,000 g / mol or more, or 2,000,000 g / mol or less, 1,500,000 g / mol or less, 1,000,000 g / mol or less, 800,000 g / mol or less, 600,000 g / mol or less, or 500,000 g / mol or less.

[0041] In this specification, the term second binder may also be referred to as a short-chain binder. The weight average molecular weight of the second binder may be, in other examples, 40,000 g / mol or less, 30,000 g / mol or less, 20,000 g / mol or less, or 10,000 g / mol or less, or 3,000 g / mol or more, 4,000 g / mol or more, or 5,000 g / mol or more.

[0042] The ratio of the weight average molecular weight of the second binder to the first binder may be, for example, 25 or more. The ratio of the weight average molecular weight of the second binder to the first binder may be, in other examples, 30 or more, 35 or more, 40 or more, or 45 or more, or 1000 or less, 500 or less, 100 or less, or 50 or less.

[0043] In the present invention, the second binder may include, for example, a thiol group. The present invention can provide a positive electrode having excellent dispersibility and adhesive strength by allowing the second binder to include a thiol group.

[0044] The weight ratio of the second binder to the first binder may be, for example, 0.1 to 10. In other examples, the weight ratio of the second binder to the first binder may be 0.2 or more, 0.3 or more, 0.4 or more, 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more, or 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, or 2 or less. The present invention can provide a positive electrode having excellent dispersibility and also excellent inter-particle and / or interfacial adhesion by controlling the weight ratio of the second binder to the first binder included in the positive electrode active material layer within the above range.

[0045] The weight ratio of the thiol group in the second binder may be, for example, 0.05 to 5 wt%. In the present specification, the weight ratio of the thiol group in the second binder may mean, for example, the weight ratio of the thiol group included in the second binder to the second binder. The weight ratio of the thiol group in the second binder may be, in other examples, 0.1 wt% or more, 0.2 wt% or more, 0.3 wt% or more, or 0.4 wt% or more, or 4 wt% or less, 3 wt% or less, 2 wt% or less, or 1 wt% or less. The present invention can provide a positive electrode having excellent dispersibility and, accordingly, excellent 1.0C high-rate discharge efficiency and capacity retention according to cycles by controlling the weight ratio of the thiol group in the second binder as described above.

[0046] The first binder and the second binder may each be characterized by being at least one selected from the group consisting of, for example, styrene-butadiene rubber, acrylated styrene-butadiene rubber, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinylidene fluoride, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyvinylpyrrolidone, polytetrafluoroethylene, polyvinylidene, butadiene rubber, styrene-butadiene-styrene rubber, and styrene-panacene-styrene rubber.

[0047] The present invention may relate to a positive electrode, characterized in that it comprises, for example, 0.1 to 20 parts by weight of a binder with respect to 100 parts by weight of the positive electrode active material. In another example, the present invention may comprise, with respect to 100 parts by weight of the positive electrode active material, 0.5 parts by weight or more, 1 part by weight or more, 15 parts by weight or less, or 10 parts by weight or less of the binder.

[0048] The above-mentioned positive electrode active material reversibly absorbs and desorbs lithium ions. The positive electrode active material may be, but is not limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide, and any material used as a positive electrode active material in the art may be used. The positive electrode active materials may be used alone or in combination of two or more.

[0049] The above lithium transition metal oxide is, for example, Li a A1-b B b D2 (in the above formula, 0.90≤a≤1, and 0≤b≤0.5); Li a Ni 1-b-c Co b B c O 2-α F2 (in the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0 <α<2); Li a Ni 1-b-c Mn b B c D α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0≤α≤2); Li a Ni 1-b-c Co b B c D α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a E 1-b B b O 2-c D c (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05); LiE 2-b B b O 4-c D c (In the above formula, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b B c O 2-α F α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a CoG b O2 (in the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a MnG b O2 (in the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Mn2GbO4 (in the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Ni 1-b-c Mn bB c O 2-α F α (In the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c Mn b B c O 2-α F2 (in the above formula, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni b E c G d O2 (in the above formula, 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Co c Mn d GeO2 (in the above formula, 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0 ≤d≤0.5, 0.001≤e≤0.1); Li a NiG b O2 (in the above formula, 0.90≤a≤1, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3- f) J2(PO4)3(0≤f≤2); Li (3-f)Fe2(PO4)3(0≤f≤2); It may be a compound represented by any one of the chemical formulas of LiFePO4. In this compound, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 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 is Cr, V, Fe, Sc, Y, or a combination thereof; J may be V, Cr, Mn, Co, Ni, Cu, or a combination thereof. A compound having a coating layer added to the surface of this compound may be used as the positive electrode active material, or a mixture of the above-mentioned compound and the compound having a coating layer added may be used. The coating layer added to the surface of such compounds may contain, for example, a lithium ion conductive oxide. The lithium ion conductive oxide may be, for example, LiNbO3, Li4Ti5O. 12 , Li3PO4, etc., but are not limited thereto. The compound forming the coating layer may be amorphous or crystalline. The method for forming the coating layer may include, for example, spray coating, dipping, etc., but may be selected without limitation within a range that does not adversely affect the properties of the positive electrode active material.

[0050] When the above-mentioned cathode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), it may be possible to increase the capacity density of the all-solid-state battery and reduce metal dissolution of the cathode active material in a charged state. Accordingly, the cycle characteristics of the all-solid-state battery in a charged state may be improved.

[0051] The shape of the above-mentioned positive electrode active material may be, for example, a particle shape such as a sphere, an ellipse, or a sphere. The particle size of the positive electrode active material is not particularly limited and may be within the range applicable to positive electrode active materials of conventional all-solid-state secondary batteries.

[0052] The positive electrode active material layer of the present invention may, for example, include 60 to 90 parts by weight of the positive electrode active material per 100 parts by weight of the positive electrode active material layer, but is not limited thereto, and may be any range applicable to the positive electrode of a conventional all-solid-state secondary battery.

[0053] The above sulfide-based solid electrolytes include, for example, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-LiBr-LiI-P2S5, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-Li3PO4, Li2S-SiS2- Li p MO q (p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, and In), Li2S-SiS2-P2S5-LiI, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers), Z is one of Ge, Zn or Ga, L i2 S-GeS2, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x It can be characterized by being at least one selected from the group including (0≤x≤2).

[0054] A sulfide-based solid electrolyte can be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, a heat treatment can be performed after such treatment. The solid electrolyte can be in an amorphous, crystalline, or mixed state. In the present invention, the sulfide-based solid electrolyte can be, for example, one that includes sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements among the above-mentioned sulfide-based solid electrolyte materials.

[0055] The above sulfide-based solid electrolyte is, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0056] The density of the above-mentioned argyrodite-type solid electrolyte may be, for example, 1.5 to 2.0 g / cc. Since the above-mentioned argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state secondary battery is reduced, and penetration of the solid electrolyte by Li can be effectively suppressed.

[0057] The elastic modulus of the above solid electrolyte may be, for example, 15 to 35 GPa, but is not limited thereto.

[0058] In the present invention, for example, 10 to 30 parts by weight of a solid electrolyte may be included for 100 parts by weight of the positive electrode active material, but is not limited thereto, and may be any range applicable to the positive electrode of a conventional all-solid-state secondary battery.

[0059] The above-described positive electrode active material layer may be characterized by further including, for example, a conductive material. The conductive material included in the positive electrode active material layer may be, for example, graphite, carbon black, acetylene black, ketene black, carbon fiber, or metal powder.

[0060] The above-mentioned positive electrode active material layer may include, for example, 0.1 to 10 parts by weight of a conductive material per 100 parts by weight of the positive electrode active material, but is not limited thereto, and may be any range applicable to the positive electrode of a conventional all-solid-state secondary battery.

[0061] In addition to the above-mentioned positive electrode active material layer, the positive electrode active material layer may further include additives such as fillers, coating agents, dispersants, and ion conductive assistants, and these additives may be used without limitation as long as they are known materials generally used in electrodes of all-solid-state batteries.

[0062] The present invention can provide a positive electrode having excellent dispersibility through a combination of the above-described configurations.

[0063] In one example, the particle size distribution analysis results for the above positive electrode active material layer, D 95 may be 15 ㎛ or less. The particle size distribution analysis result for the positive electrode active material layer may be measured in a manner according to the evaluation example described below. In another example, the particle size distribution analysis result for the positive electrode active material layer, D 95The positive electrode active material layer of the positive electrode according to the present invention may have excellent dispersibility so that agglomeration between particles can be controlled, thereby reducing the size of the particles.

[0064] In one example, the particle size distribution analysis results for the above positive electrode active material layer, D 90 This may be 5 ㎛ to 14 ㎛. In another example, the particle size distribution analysis result for the active material layer, D 90 It may be 13 ㎛ or less, 12 ㎛ or less, 11 ㎛ or less, 10 ㎛ or less, 9 ㎛ or less, or 8 ㎛ or less, or 5.5 ㎛ or more, 6 ㎛ or more, 6.5 ㎛ or more, or 7 ㎛ or more.

[0065] In one example, the particle size distribution analysis results for the above positive electrode active material layer, D 50 This may be 2 ㎛ to 8 ㎛. In another example, the particle size distribution analysis result for the active material layer, D 50 It may be 7 ㎛ or less, 6.5 ㎛ or less, 6 ㎛ or less, 5.5 ㎛ or less, or 5 ㎛ or less, or 2.5 ㎛ or more, 3 ㎛ or more, 3.5 ㎛ or more, or 4 ㎛ or more.

[0066] In one example, the particle size distribution analysis results for the above positive electrode active material layer, D 10 This may be 2 ㎛ or less. In another example, the particle size distribution analysis result for the active material layer, D 10 The positive electrode active material layer of the positive electrode according to the present invention may have excellent dispersibility so that agglomeration between particles can be controlled.

[0067] In one example, the particle size distribution analysis results for the above positive electrode active material layer, D 90 / D 10 This may be 8 to 12. In another example, the particle size distribution analysis result for the positive electrode active material layer is D 90 / D 10 This can be 9 or more, or 10 or more, or 11 or less. D 90 / D 10 When the above range is satisfied, it can be seen that all particles are evenly distributed without excessive fine or coarse particles being contained within the positive electrode active material layer, resulting in high dispersibility.

[0068] In one example, the particle size distribution analysis results for the above positive electrode active material layer, (D 90 -D 50 ) / (D 50 -D 10 ) may be 0.7 to 1.3. In another example, the particle size distribution analysis results for the positive electrode active material layer are (D 90 -D 50 ) / (D 50 -D 10 ) may be less than or equal to 1.25, less than or equal to 1.2, less than or equal to 1.15, or less than or equal to 1.13, or greater than or equal to 0.8, greater than or equal to 0.85, greater than or equal to 0.9, greater than or equal to 1, or greater than or equal to 1.1. (D 90 -D 50 ) / (D 50 -D 10 ) satisfies the above range, it can be seen that the slurry particle size distribution is narrowly formed around the average particle diameter within the positive electrode active material layer, and the slurry is stably dispersed.

[0069] In one example, the particle size distribution analysis results for the above positive electrode active material layer, (D 95 -D 10 ) / D 50 This may be 1.8 to 2.4. In another example, the particle size distribution analysis results for the positive electrode active material layer are (D 95 -D 10 ) / D50 This can be 1.9 or more, or 2 or more, or 2.3 or less, 2.2 or less, or 2.1 or less. (D 95 -D 10 ) / D 50 When the above range is satisfied, it can be seen that the slurry particle size distribution is narrowly formed based on the average particle diameter within the positive electrode active material layer, and the slurry is stably dispersed.

[0070] The positive electrode of the present invention may further include, for example, a positive electrode current collector. The positive electrode current collector may be a known metal usable as a current collector of an all-solid-state battery. The positive electrode current collector may be, for example, a plate, mesh, or foil made of copper (Cu), nickel (Ni), aluminum (Al), vanadium (V), gold (Au), platinum (Pt), chromium (Cr), iron (Fe), zinc (Zn), indium (In), germanium (Ge), lithium (Li), magnesium (Mg), stainless steel, titanium (Ti), cobalt (Co), or an alloy thereof. The positive electrode current collector may be omitted in some cases.

[0071] The anode of the present invention may have, for example, an adhesive strength of 30 gf / cm or more. The adhesive strength of the anode may be measured in a manner according to an evaluation example described below. In other examples, the anode of the present invention may have an adhesive strength of 35 gf / cm or more, 40 gf / cm or more, 45 gf / cm or more, 50 gf / cm or more, 55 gf / cm or more, 60 gf / cm or more, 65 gf / cm or more, or 70 gf / cm or more, or 150 gf / cm or less, 140 gf / cm or less, 130 gf / cm or less, 120 gf / cm or less, 110 gf / cm or less, 100 gf / cm or less, 90 gf / cm or less, or 80 gf / cm or less.

[0072] The second aspect of the present invention relates to a method for manufacturing an anode.

[0073] Matters relating to the first aspect of the present invention may be equally applied to matters relating to the second aspect unless specifically stated otherwise.

[0074] The present invention may relate to a method for producing a positive electrode, comprising, for example, a step of producing a positive electrode slurry by mixing a positive electrode active material, a sulfide-based solid electrolyte, and a binder in a non-polar solvent; a step of applying the positive electrode slurry onto a positive electrode current collector; and a step of drying; wherein the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder comprises a thiol group.

[0075] The above sulfide-based solid electrolyte has a problem of causing a side reaction when combined with a polar solvent, so it is necessary to introduce a non-polar solvent as a solvent. The non-polar solvent may be, for example, anisole, hexyl butyrate, octyl acetate, butyl butyrate, isobutyl isobutyrate, chloroform, hexane, tetrahydrofuran, toluene, benzene, carbon tetrachloride, carbon disulfide, or turpentine. During the applying step and the drying step, etc., a significant portion or all of the non-polar solvent may be evaporated, and therefore, the positive electrode active material layer of the final manufactured positive electrode may remain at 1 wt% or less, 0.5 wt% or less, 0.1 wt% or less, or 0.01 wt% or less, or may not be included.

[0076] The step of preparing the above positive electrode slurry may further include, for example, a step of introducing a conductive material and / or other additives.

[0077] The step of applying the above positive electrode slurry onto the positive electrode current collector may be performed by, but is not limited to, dip coating, gravure coating, slot-die coating, or doctor blade coating, for example, and any known application method may be used without limitation.

[0078] The drying step may be characterized in that it is performed, for example, at 70 to 130° C. in an air environment for 4 to 20 hours. In another example, the drying step may be performed at a temperature of 85° C. or higher, 90° C. or higher, or 95° C. or higher, or 125° C. or lower, 120° C. or lower, 115° C. or lower, 110° C. or lower, or 105° C. or lower, for 5 hours or more, 6 hours or more, or 7 hours or more, or 19 hours or less, 18 hours or less, 17 hours or less, 16 hours or less, 15 hours or less, 14 hours or less, 13 hours or less, 12 hours or less, 11 hours or less, 10 hours or less, or 9 hours or less in an air environment.

[0079] The third aspect of the present invention relates to an all-solid-state battery.

[0080] Matters relating to the first or second aspect of the present invention may be equally applied to matters relating to the third aspect unless specifically stated otherwise.

[0081] The present invention may relate to an all-solid-state battery, for example, comprising a positive electrode and a solid electrolyte layer, wherein the positive electrode comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material, a solid electrolyte, and a binder, the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder comprises a thiol group.

[0082] Matters concerning all-solid-state batteries are not limited to those mentioned below, and general contents concerning lithium-ion secondary batteries or all-solid-state batteries, including the following contents, may be applied without limitation as long as they do not impede the purpose of the present invention.

[0083] The above solid electrolyte layer may include, but is not limited to, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte, and may be any electrolyte commonly used in an all-solid-state battery. The sulfide-based solid electrolyte included in the solid electrolyte layer may be, for example, at least one of the examples of the sulfide-based solid electrolyte included in the above-described positive electrode active material layer, and may be the same as or different from the sulfide-based solid electrolyte included in the positive electrode active material layer. The oxide-based solid electrolyte may be, for example, at least one of a Garnet-type solid electrolyte, a Nasicon-type solid electrolyte, a LISICON-type solid electrolyte, or a perovskite-type solid electrolyte. Specifically, the oxide-based solid electrolyte may be Li7La3Zr2O 12 , the above Li7La3Zr2O 12 Doped with elements such as Al, Y, Ga, Ta, Nb, etc. instead of Li, or the above Li7La3Zr2O 12 Ga in the place of Li, La, and Zr elements +3 -Sc +3 Multi-doped ones, etc. are used; those coated with materials such as Al2CO3, Ge, ZnO, etc. on the surface are used; Na 1+x Zr2Si2P 3-X O 12 (0≤x≤3), LiM2(PO4)3(M = Zr, Ti, Ge), Li 1+x Al x M 2-x (PO4)3(0 <x<2, M=Zr, Ti, Ge) 또는 상기 Al 대신 Y, La, Sc 등의 산화수가 +3인 원자를 도핑하거나 Sr, Mg, Ca 등의 산화수가 +2인 원자를 도핑한 것 등이 사용되거나; xLi3AO4-(1-x) Li4BO4(A: P, As, V 등, B: Si, Ge, Ti 등) 또는 이에 대해 Li3BO3등을 첨가한 것 등; 또는 Li3x La 2 / 3-x □ 1 / 3- 2x TiO3(LLTO, 0 <x<0.16, □는 공공(vacancy)), La 0.57-2x / 3 Sr x Li 0.3 TiO3, etc. can be used, but are not limited thereto. The halide-based solid electrolytes include Li2ZrCl6, Li 2+x Zr 1-x M x Cl6(M= Fe, Cr, V) and Na2ZrCl6 can be used, but are not limited thereto.

[0084] The shape of the solid electrolyte may be, for example, a particle type. In addition, the average particle diameter (D50) of the solid electrolyte may be, for example, in the range of 0.5 to 2 μm. The solid electrolyte may be used singly or in combination of two or more. If the solid electrolyte layer includes two or more solid electrolytes, the two or more solid electrolytes may be mixed and used in one layer, or a separate layer including each solid electrolyte may be formed to form a multilayer structure, or the respective solid electrolytes may be mixed and the mixing ratios may be the same or different to form a separate layer to form a multilayer structure. In the present specification, the average particle diameter (D50) may mean a diameter at which the cumulative volume of the particles is half (50%) of the total volume when the particle diameters of the particles measured by laser diffraction scattering particle diameter distribution measurement are arranged in descending order.

[0085] The solid electrolyte layer may further contain, for example, a binder. The binder may be, for example, an aqueous binder, an organic binder, or a combination thereof. The binder may be, for example, a polymer including polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinylidene fluoride, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene, fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylate styrene-butadiene rubber, epoxy resin, nylon, or a combination thereof. The aqueous binder may be, for example, styrene butadiene rubber, carboxymethyl cellulose, or a combination thereof. The organic binder may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, or a combination thereof, but is not limited thereto, and any known binder may be used without limitation as long as it does not impede the purpose of the present invention. The solid electrolyte layer may contain, for example, 5 wt% or less of the binder.

[0086] The thickness of the above solid electrolyte layer is not particularly limited, but may typically be within the range of 0.1 ㎛ to 1 mm.

[0087] The all-solid-state battery of the present invention may further include a negative electrode.

[0088] The above negative electrode may, in one example, include a negative electrode active material layer. The negative electrode active material layer may include, for example, a negative electrode active material, and may optionally further include a solid electrolyte, a conductive material, and / or a binder.

[0089] The above negative active material is, for example, lithium, lithium alloy, carbon, silicon, silicon alloy or Li4Ti5O 12 (LTO), or the lithium, lithium alloy, carbon, silicon, silicon alloy or Li4Ti5O12 (LTO) and an alloy with at least one metal selected from the group consisting of Sn, Ge, and Al.

[0090] The above-mentioned solid electrolyte, conductive material and / or binder, etc. may be one of the types included in the above-mentioned positive electrode or solid electrolyte layer, but are not limited thereto, and any solid electrolyte, conductive material and / or binder used in the relevant technical field may be possible. The solid electrolyte, conductive material and / or binder included in the negative electrode active material layer may be the same as or different from the solid electrolyte, conductive material and / or binder included in the positive electrode active material layer, solid electrolyte layer, etc.

[0091] The above-mentioned negative active material layer may also further include, for example, other additives. These additives may be used without limitation as long as they are known materials generally used in electrodes of all-solid-state batteries.

[0092] The negative electrode may further include a negative electrode current collector. The negative electrode current collector may be a known metal that can be used as a current collector of an all-solid-state battery. The negative electrode current collector may be, for example, a material that does not form an alloy or compound with lithium. The negative electrode current collector may be, for example, selected from the group consisting of copper (Cu), nickel (Ni), aluminum (Al), vanadium (V), gold (Au), platinum (Pt), magnesium (Mg), iron (Fe), titanium (Ti), cobalt (Co), chromium (Cr), zinc (Zn), germanium (Ge), indium (In), and stainless steel, but is not limited thereto. Any material used as an electrode current collector in the relevant technical field may be used as long as it does not impede the purpose of the present invention. The negative electrode current collector may be composed of one of the above-mentioned metals, or may be composed of an alloy or a coating material of two or more metals. The above negative electrode collector may be, for example, in the form of a plate, mesh, or foil, but is not limited thereto.

[0093] In another example, when an all-solid-state battery uses lithium or a lithium alloy as an anode active material, the anode may include lithium or a lithium alloy as an anode active material layer during the battery manufacturing process (from the initial manufacturing), or a lithium layer may be formed during the charging process without forming a separate anode active material layer during the battery manufacturing process.

[0094] In the above battery manufacturing process, if a separate negative active material layer is not formed, the all-solid-state battery of the present invention may include a non-cathode coating layer between the solid electrolyte layer and the negative current collector, or, if there is no negative current collector, on the surface of the non-cathode coating layer opposite to the solid electrolyte layer.

[0095] In this specification, the term "anode-free coating layer" means a coating layer formed between an anode current collector and a solid electrolyte layer, or on one side of a solid electrolyte layer when an anode current collector is absent, in an all-solid-state battery in which lithium is absorbed into the anode-free coating layer during charging and the charge capacity of the anode-free coating layer is exceeded, lithium is deposited between the anode current collector and the anode-free coating layer, or in the case where there is no anode current collector, on the side of the anode-free coating layer opposite to the solid electrolyte layer, to form a metal layer, and in which lithium in the anode-free coating layer and the lithium metal layer is ionized and moves toward the cathode during discharge, the coating layer may be different from the aforementioned anode active material layer in its composition and operating mechanism. The anode-free coating layer can act as a protective layer for the lithium metal layer by covering the lithium metal layer during the charging process and can suppress the precipitation and growth of lithium dendrites, thereby suppressing short-circuiting and capacity reduction of the all-solid-state battery and improving performance, etc.

[0096] The above-described non-anode coating layer may include, for example, amorphous carbon. The amorphous carbon included in the non-anode coating layer may be, for example, at least one selected from the group consisting of carbon black, acetylene black, furnace black, Ketjen black, and graphene, but is not limited thereto. Any amorphous carbon that can be used in a non-anode all-solid-state battery may be used without limitation.

[0097] The above-described non-cathode coating layer may further include, for example, a lithium-affinity element that forms an alloy or compound with lithium. The lithium-affinity element may be, for example, at least one metal, metalloid element, or a combination thereof selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0098] The particle size of the lithium-affinity element may be, for example, in the range of 10 to 1000 nm. The particle size may refer to a maximum particle size, a minimum particle size, or an average particle size. In other examples, the particle size of the lithium-affinity element may be 20 nm or more, 30 nm or more, 40 nm or more, or 50 nm or more, or 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, or 100 nm or less.

[0099] The above-described non-cathode coating layer may further include, for example, a binder. The binder may be selected from the binders mentioned as being included in the aforementioned positive electrode active material layer, solid electrolyte layer, negative electrode active material layer, etc., or may be any known binder without limitation.

[0100] An anode current collector may optionally be further included on one side of the above-described non-cathode coating layer, and the above-described anode current collector may be used without limitation.

[0101] When the all-solid-state battery includes a non-anode coating layer, the all-solid-state battery may further include a thin film including an element capable of forming an alloy with lithium, for example. The thin film may be included between the negative electrode current collector and the non-anode coating layer, or on at least one surface of both surfaces of the non-anode coating layer when there is no negative electrode current collector. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., but is not limited thereto, and any element capable of forming an alloy with lithium in the art may be used. The thin film may be composed of one of the examples above or may be composed of various types of alloys. When the all-solid-state battery of the present invention further includes such a thin film, the cycle characteristics of the all-solid-state battery may be further improved.

[0102] The thickness of the above thin film may be, for example, 1 to 800 nm, 10 to 700 nm, 50 to 600 nm, or 100 to 500 nm. The above thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc., but is not limited thereto, and any method capable of forming a thin film in the relevant technical field may be used.

[0103] When including the above-described non-cathode coating layer, the all-solid-state battery may further include a metal and / or a metal layer thereof including lithium or a lithium alloy, for example, between the negative electrode current collector and the non-cathode coating layer, on one side of the non-cathode coating layer opposite to the solid electrolyte layer, and / or within the non-cathode coating layer, by charging. The lithium alloy may be, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., and any lithium alloy used in the art may be used. The metal or metal layer included between the negative electrode current collector and the non-cathode coating layer, and / or within the non-cathode coating layer may be composed of one of these alloys, lithium, or may be composed of multiple types of alloys.

[0104] The thickness of the metal layer including the lithium or lithium alloy may be, for example, in a range of 1 to 1000 μm, 1 to 500 μm, 1 to 200 μm, 1 to 150 μm, 1 to 100 μm or 1 to 50 μm. The thickness needs to be controlled as described above so that the metal layer can perform its role as a lithium storage well and improve cycle characteristics.

[0105] The metal layer may be formed by deposition, for example, between the negative current collector and the non-anode coating layer, or on the surface of the non-anode coating layer opposite to the solid electrolyte layer among the two sides of the non-anode coating layer, by charging after assembling the all-solid-state battery. When the metal layer is formed by charging after assembling the all-solid-state battery, the region between the negative current collector and the non-anode coating layer, or on the surface of the non-anode coating layer opposite to the solid electrolyte layer among the two sides of the non-anode coating layer, may be, for example, a lithium-free region that does not contain lithium in the initial state or the post-discharge state of the all-solid-state battery.

[0106] In one embodiment, the all-solid-state battery according to the present invention may have a ratio (%) of 1.0C capacity to 0.1C capacity of 87% or more. The high-rate discharge efficiency may be measured in a manner according to the evaluation example below. In another example, the all-solid-state battery of the present invention may have a ratio (%) of 1.0C capacity to 0.1C capacity of 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, or 94% or more, or 99.9% or less, 99% or less, or 95% or less. The all-solid-state battery of the present invention may have excellent high-rate discharge efficiency because the dispersibility within the positive electrode is excellent and solid electrolyte agglomeration, etc., is controlled.

[0107] In one embodiment, the all-solid-state battery according to the present invention may have a capacity retention rate according to a cycle of 90% or more. The capacity retention rate according to the cycle is measured in a manner according to the evaluation example below, and may refer to a capacity retention rate after 120 cycles. The capacity retention rate after 120 cycles may refer to, for example, the percentage of the capacity at 120 cycles to the capacity at 1 cycle. In another embodiment, the all-solid-state battery according to the present invention may have a capacity retention rate according to a cycle of 90.5% or more, 91% or more, 91.5% or more, 92% or more, 92.5% or more, 93% or more, or 93.5% or more, or 99.9% or less, 99% or less, or 95% or less. The all-solid-state battery of the present invention may have excellent capacity retention rate according to a cycle because the positive electrode has excellent adhesiveness and can effectively buffer shrinkage and expansion of the positive electrode.

[0108] Hereinafter, the present invention will be described in detail by way of examples to specifically illustrate the disclosure of the present invention and its intended functions and effects, as described above. However, these examples may be modified in various ways, and the scope of this specification is not construed as being limited to these examples. It is emphasized that these examples are provided to represent the present invention and to provide a more concrete explanation to those skilled in the art.

[0109] Manufacturing example. Manufacturing of a short-chain binder containing a thiol group.

[0110] A “thiol group-containing short-chain binder” containing 0.5 wt% of thiol groups in SBR (Styrene Butadien Rubber) having a weight average molecular weight of ~10,000 g / mol was prepared.

[0111] Specifically, 20 g of styrene and 80 g of 1,3-butadiene were placed in a 1 L polymerization reactor capable of stirring and heating, and then added to 180 g of ion-exchanged water and stirred. 5 g of sodium stearate was added as an emulsifier and 0.3 g of tertiary dodecyl mercaptan was added as a chain transfer agent. After heating to 50°C in a nitrogen atmosphere, 0.3 g of potassium persulfate was added as an initiator to initiate the polymerization reaction. The reaction was carried out by maintaining 50°C for 10 hours to synthesize a short-chain binder. Afterwards, 5 g of the synthesized binder was stirred in 100 mL of p-xylene, and ethanethiol was added so that the butadiene to thiol group ratio was 50:1. Afterwards, 0.5 g of a photoinitiator, 2,2′-azoisobutyronitrile (AIBN), was added, and a thiol-ene click reaction of the binder was induced using UV rays, thereby synthesizing a short-chain binder containing a thiol group.

[0112] Example 1. Preparation of the anode

[0113] Cathode active material (LiNi) 0.8 Co 0.15 Mn 0.05O2(NCM)), solid electrolyte (Li6PS5Cl, which is an argyrodite type crystal), conductive material (Carbon black), and binder were added to a solvent (Anisole, Hexyl butyrate, Octyl acetate, Butyl butyrate, Isobutyl isobutyrate, etc.) at a weight ratio of 75~80 : 15~20 : 1~5 : 1~5 to prepare a sulfide-based all-solid-state battery composite cathode slurry. At this time, the binder was used as a mixture of 'thiol group-containing short-chain binder according to the manufacturing example' and 'SBR (Styrene Butadien Rubber) having a weight average molecular weight of 450,000 to 500,000 g / mol' at a weight ratio of 1:1.

[0114] Next, the positive electrode slurry was applied onto an aluminum foil having a thickness of 300 to 400 μm and dried at 100°C for 10 to 15 hours in an air environment to obtain a positive electrode including a positive electrode active material layer having a thickness of 200 to 250 μm.

[0115] The initial charge capacity (charge capacity at the first cycle) of the manufactured positive electrode was approximately 20 mAh at 4.25 V charge, and the positive electrode weight was approximately 110 mg (approximately 203 mAh / g per active material weight).

[0116] Comparative Example 1.

[0117] A positive electrode was obtained in the same manner as in Example 1, except that only ‘SBR (Styrene Butadien Rubber) having a weight average molecular weight of 450,000 to 500,000 g / mol’ was used as a binder.

[0118] Comparative Example 2.

[0119] A positive electrode was obtained in the same manner as Example 1, except that only the ‘thiol group-containing short-chain binder according to the manufacturing example’ was used as a binder.

[0120] Evaluation Example 1. Particle Size Distribution

[0121] (Slurry sample separation)

[0122] A portion of the positive electrode slurry of the above examples and comparative examples was taken and diluted in a xylene solution to prepare an analysis sample.

[0123] (analytical device)

[0124] The particle size of the above sample was analyzed using a particle size analyzer (Mastersizer 3000, Malvem panalytical).

[0125] Specifically, the analysis samples prepared above were each placed into the sample inlet of the device, and particle size analysis was performed under the following setting conditions.

[0126] ⊙ Particle Type: Nickel Oxide NiO

[0127] ⊙ Material:

[0128] - Material name: Nickel Oxide NiO

[0129] - Refractive index: 2.182

[0130] - Adsorption index: 0.010

[0131] ⊙ light source:

[0132] - Red light source: Max. 4mW He-Ne, 632.8nm

[0133] - Blue light source: Max. 10mW LED, 470nm

[0134] ⊙ Dispersant:

[0135] - Dispersant name: Xylene

[0136] Refractive index: 1.430

[0137] ⊙ Measurement obscuration limits: 9-15%

[0138] ⊙ Analysis model: Mie scattering

[0139] The results of the particle size distribution analysis based on the volume of the positive slurry according to the above method are shown in Table 1 below.

[0140] Evaluation Example 2. Adhesion Evaluation

[0141] The positive electrodes of the examples and comparative examples were cut to a size of 10 cm × 2 cm, and the positive electrode active material layer side was adhered to a slide glass with double-sided tape and laminated to prepare a sample for a peel test. Next, a 90° peel test was performed on the sample using a UTM machine. The specific analysis conditions were as follows, and the evaluation results are shown in Table 1 below.

[0142] <Analysis Conditions>

[0143] -Sample width: 20 mm

[0144] - Peeling speed: 200 mm / min

[0145] -Data valid calculation range: 10mm to 40mm

[0146]

[0147] Evaluation Example 3. Monocell Performance Evaluation

[0148] An all-solid-state battery was manufactured by sequentially stacking a negative electrode current collector (Sus foil), lithium metal, a sulfide-based solid electrolyte membrane composed of Li6PS5Cl, and a positive electrode and a negative electrode current collector (Al foil) according to an example or comparative example. Here, each part of the positive electrode current collector and the negative electrode current collector was protruded out of the pouch so that the battery could maintain a vacuum, and these protrusions were used as positive and negative electrode terminals. In addition, this all-solid-state battery was subjected to a hydrostatic treatment at 500 MPa for 30 minutes. By performing this hydrostatic treatment, the characteristics as a battery are significantly improved.

[0149] All-solid-state batteries (pouch-type monocells) each including the positive electrodes of Example 1 and Comparative Examples 1 and 2 were driven under the following charge / discharge condition 1 at an operating voltage range of 4.25 V to 3.0 V and an operating temperature of 60°C, and the capacity retention rates at 0.33 C, 0.5 C, and 1.0 C were evaluated compared to the first discharge capacity at 0.1 C, and the results are shown in Fig. 1 and Table 2. In addition, under the above conditions, the capacity retention rates according to the cycle were evaluated by driving under the following charge / discharge condition 2, and the results are shown in Fig. 2 and Table 2.

[0150] <Charge / Discharge Condition 1>

[0151] Charging conditions: 0.1C, 4.25V CC / CV, 0.05C cut-off

[0152] Discharge conditions: 0.1C 2 times, 0.33C, 0.5C or 1.0C, 3.0V, CC

[0153] <Charge / Discharge Condition 2>

[0154] Charge conditions: 0.33C, 4.25V CC / CV, 0.05C cut-off

[0155] Discharge conditions: 0.33C, 3.0V, CC

[0156]

[0157] As a result, Comparative Example 1 had a 1.0C high-rate discharge efficiency of 86.8%, which was inferior to that of Example 1 by 91%, and Comparative Example 2 had a capacity retention rate of 88.4% at 120 cycles, which was inferior to that of Example 1 by 94%. In the case of Example 1, since the dispersibility within the positive electrode was excellent and the agglomeration of solid electrolytes was controlled, thereby improving the ion conductivity characteristics, and at the same time, securing mechanical properties that can effectively buffer the shrinkage and expansion of the positive electrode that occurs during repeated cycles, it is thought that it can have excellent high-rate discharge efficiency and capacity retention characteristics according to the cycle.

Claims

1. An anode including a positive electrode active material layer, The above cathode active material layer comprises a cathode active material, a sulfide-based solid electrolyte and a binder, The above binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, An anode, characterized in that the second binder comprises a thiol group.

2. A positive electrode according to claim 1, characterized in that the weight ratio of the second binder to the first binder is 0.1 to 10.

3. A positive electrode according to claim 1, characterized in that the weight ratio of the thiol group in the second binder is 0.05 to 5 wt%.

4. The anode according to claim 1, wherein the first binder and the second binder are each at least one selected from the group consisting of styrene-butadiene rubber, acrylated styrene-butadiene rubber, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinylidene fluoride, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyvinyl pyrrolidone, polytetrafluoroethylene, polyvinylidene, butadiene rubber, styrene-butadiene-styrene rubber, and styrene-panacene-styrene rubber.

5. A positive electrode characterized in that it contains 0.1 to 20 parts by weight of a binder per 100 parts by weight of the positive electrode active material in the first paragraph.

6. In the first paragraph, the sulfide-based solid electrolyte is Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-LiBr-LiI-P2S5, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-Li3PO4, Li2S-SiS2- Li p MO q(p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, and In), Li2S-SiS2-P2S5-LiI, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers), Z is one of Ge, Zn or Ga, L i2 S-GeS2, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x An anode characterized by having at least one selected from the group comprising (0≤x≤2).

7. A positive electrode according to claim 1, characterized in that the positive electrode active material layer further includes a conductive material.

8. In the first paragraph, the particle size distribution analysis result for the positive electrode active material layer, D 95 An anode characterized by having a thickness of 15 ㎛ or less.

9. In the first paragraph, the particle size distribution analysis result for the positive electrode active material layer, D 90 / D 10 A cathode characterized by having 8 to 12.

10. In the first paragraph, the particle size distribution analysis result for the positive electrode active material layer, (D 90 -D 50 ) / (D 50 -D 10 ) is characterized by being 0.7 to 1.

3.

11. In the first paragraph, the particle size distribution analysis result for the positive electrode active material layer, (D 95 -D 10 ) / D 50 A cathode characterized by being 1.8 to 2.

4.

12. An anode according to claim 1, characterized in that the adhesive strength is 30 gf / cm or more.

13. A step of preparing a cathode slurry by mixing a cathode active material, a sulfide-based solid electrolyte, and a binder in a nonpolar solvent; A step of applying the above positive electrode slurry onto the positive electrode current collector; and a drying step; comprising; A method for manufacturing a positive electrode, characterized in that the binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, and the second binder contains a thiol group.

14. A method for manufacturing an anode, characterized in that in the 13th paragraph, the drying step is performed at 70 to 130° C. for 4 to 20 hours in an atmospheric environment.

15. An all-solid-state battery comprising a positive electrode and a solid electrolyte layer, The above positive electrode includes a positive electrode active material layer, The above cathode active material layer includes a cathode active material, a solid electrolyte, and a binder, The above binder comprises a first binder having a weight average molecular weight of 300,000 g / mol or more and a second binder having a weight average molecular weight of 50,000 g / mol or less, An all-solid-state battery, characterized in that the second binder comprises a thiol group.

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