Negative electrode coating layer comprising zeolite and all-solid-state battery comprising same

Abstract

The present invention relates to a negative electrode comprising a negative electrode coating layer including a carbon material, a lithiophilic material, and zeolite, and to an all-solid-state battery comprising same. According to the present invention, it is possible to provide a negative electrode coating layer and an all-solid-state battery comprising same, in which zeolite acts as an adsorbent for residual moisture and / or hydrogen sulfide gas generated during battery operation, thereby improving battery life characteristics.

Description

A cathode coating layer containing zeolite and an all-solid-state battery containing the same

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0174027 filed November 28, 2024, and all contents disclosed in the document of said Korean Patent Application are incorporated herein as part of this specification.

[0002] The present invention relates to a negative electrode coating layer and an all-solid-state battery including the same.

[0003] With the increasing technological development and demand for electronic devices, society's overall dependence on electrical energy is growing, leading to a rapid increase in the demand for secondary batteries capable of efficiently storing and utilizing electrical energy. Accordingly, there is a need for technological development in lithium-ion batteries that offer improved safety along with enhanced lifespan and charging capacity.

[0004] Since lithium-ion batteries using liquid electrolytes have a structure in which the negative and positive electrodes are separated by a separator, if the separator is damaged by deformation or external impact, a short circuit may occur, which can lead to risks such as overheating or explosion.

[0005] On the other hand, all-solid-state batteries using solid electrolytes can increase battery safety and improve battery reliability by preventing electrolyte leakage. However, these all-solid-state batteries have a problem in which lithium dendrites form on the lithium metal anode during repeated charging and discharging, causing a short circuit in the cell. In addition, solid electrolytes, particularly sulfide-based solid electrolytes, can cause problems that reduce the charge-discharge efficiency of the battery by generating hydrogen sulfide gas through reaction with residual moisture in the battery.

[0006] Accordingly, there is a need to develop a negative electrode coating layer that uses a solid electrolyte while minimizing the occurrence of lithium dendrites and removing hydrogen sulfide and moisture from the battery to improve lifespan characteristics.

[0007] The present invention aims to solve the above-mentioned problems by providing a negative electrode coating layer comprising a carbon material and a lithium-affinity material to suppress the formation of lithium dendrites that may occur between the coating layer and the current collector, and to improve battery characteristics by additionally including a zeolite in the negative electrode coating layer to adsorb moisture within the battery and / or hydrogen sulfide gas generated during battery operation.

[0008] The present invention relates to a cathode coating layer comprising a carbon material; a lithium-affinity material; and a zeolite.

[0009] In one embodiment, the carbon material may include at least one selected from natural graphite, artificial graphite carbon black, acetylene black, furnace black, channel black, lamp black, thermal black, Ketjen black, carbon nanotubes, carbon nanofibers, fluorinated carbon, activated carbon, graphene, graphitized carbon fibers, low-crystallinity carbon, or high-crystallinity carbon.

[0010] In one embodiment, the lithium-affinity material comprises one or more lithium-affinity elements or lithium-affinity compounds, wherein the lithium-affinity element is one or more selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), cobalt (Co), zirconium (Zr), indium (In), magnesium (Mg), aluminum (Al), bismuth (Bi), tin (Sn), chromium (Cr), copper (Cu), tungsten (W), germanium (Ge), lead (Pb), antimony (Sb), or zinc (Zn), and the lithium-affinity compound may be one or more selected from lithium carbonate, lithium titanate, or oxides, nitrides, halides, sulfides, carbides, hydrides, and hydroxides of the lithium-affinity elements.

[0011] In one embodiment, the content of the zeolite may be 5% to 55% by weight based on the total weight of the cathode coating layer.

[0012] In one embodiment, the average particle size (D of the zeolite) 50 ) can be 0.1 μm to 5 μm.

[0013] In one embodiment, the zeolite may include pores of 0.1 nm to 10 nm.

[0014] In one embodiment, the cathode coating layer may comprise the carbon material and the zeolite in a weight ratio of 0.5:1 to 10:1.

[0015] In another embodiment, the all-solid-state battery may include a positive electrode; a solid electrolyte layer; and a negative electrode comprising the negative electrode coating layer.

[0016] In one embodiment, the solid electrolyte layer may include at least one selected from a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer-based solid electrolyte, or a halide-based solid electrolyte.

[0017] In one embodiment, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, SiS2-B2S3-LiI, Li2S-SiS2-Li4SiO4, 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-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), Li 10 GeP2S 12 , 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 xIt may include at least one selected from (0≤x≤2).

[0018] In one embodiment, the thickness of the cathode coating layer may be 5 μm to 50 μm.

[0019] In one embodiment, the loading amount of the cathode coating layer is 0.1 mg / cm² 2 up to 5 mg / cm² 2 It could be.

[0020] According to the present invention, a negative electrode coating layer with improved battery life characteristics and an all-solid-state battery including the same can be provided, wherein the zeolite acts as an adsorbent for residual moisture and hydrogen sulfide gas generated during battery operation.

[0021] Figure 1 is a graph showing the performance of a battery according to an embodiment and a comparative example of the present invention.

[0022] Figure 2 is a graph showing the performance of a battery according to an embodiment and a comparative example of the present invention.

[0023] Terms and words used in this specification and claims shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0024] Therefore, the configurations of the embodiments described in this specification are merely one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention; thus, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application. In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0025] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Thus, for example, a composition comprising compound A may include compounds other than A. However, the term "comprising" also encompasses, in a more restrictive sense as a specific embodiment thereof, "essentially / essentially composed of" and "composed of," so that, for example, a "composition comprising compound A" may also be (essentially / essentially) composed of compound A.

[0026] In this regard, terms such as “to have” or “to possess,” as described in this specification, are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should not be understood as precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0027] In this specification, when any layer is described as being located "on" or "between" another arbitrary layer, this includes not only cases where the arbitrary layer is in contact with another arbitrary layer, but also cases where another layer or material, etc., exists between the two layers.

[0028] Where in this specification a quantity, concentration, or other value or parameter is given as an enumeration of a range, a preferred range, a preferred upper limit, and a preferred lower limit, it should be understood that any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether the range is disclosed separately, specifically discloses all ranges that may be formed. Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, for example, without limiting terms such as greater than or less than, the range is intended to include its endpoint value and all integers and fractions within that range. The scope of the invention is not intended to be limited to the specific value mentioned when defining the range.

[0029] In this specification, the average particle size (D 50 ) refers to the particle size at the 50% point of the cumulative distribution of the number of particles according to particle size, and the above average particle size may be measured using the laser diffraction method. Specifically, after dispersing the powder to be measured in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac S3500) to measure the difference in diffraction patterns according to particle size as the particles pass through the laser beam, thereby calculating the particle size distribution. The average particle size can be measured by calculating the particle diameter at the point that is 50% of the cumulative distribution of the number of particles according to particle size in the measuring device.

[0030] Among the physical properties mentioned in this specification, if the measured temperature affects the property, the property is measured at room temperature unless specifically otherwise specified. The term "room temperature" refers to a natural temperature that has not been heated or cooled, and may mean, for example, any temperature within the range of about 10°C to 30°C, about 23°C, or about 25°C. Furthermore, unless specifically otherwise specified, the unit of temperature in this specification is °C.

[0031] In addition, among the physical properties mentioned in this specification, if the measured pressure affects the physical property, unless otherwise specifically defined, the physical property is measured at atmospheric pressure, that is, at about 1 atmosphere.

[0032] A first aspect of the present invention relates to a cathode coating layer comprising a carbon material; a lithium-affinity material; and a zeolite.

[0033] The above carbon material comprises, for example, at least one selected from natural graphite, artificial graphite carbon black, acetylene black, furnace black, channel black, lamp black, thermal black, Ketjen black, carbon nanotubes, carbon nanofibers, fluorinated carbon, activated carbon, graphene, graphitized carbon fibers, low-crystallinity carbon, or high-crystallinity carbon, and can be used without limitation as long as it is a carbon material commonly applied to a cathode.

[0034] The above carbon material may be characterized, for example, as amorphous carbon. The above amorphous carbon has a disordered structure in which the size of the hexagonal network planes composed of carbon atoms is small and stacking growth is not well developed, and has a structure in which fine crystals composed of hexagonal network planes are entangled with each other or the fine crystals are mixed with the amorphous phase. The above amorphous carbon has excellent properties for transporting lithium ions through its surface, so that when charging, it transports lithium ions supplied from the positive electrode toward the negative electrode current collector to which negative charge is supplied, thereby inducing the formation of a metal layer containing lithium metal or a lithium alloy between the negative electrode coating layer and the negative electrode current collector.

[0035] The above amorphous carbon may be one or more selected from, for example, carbon black, acetylene black, furnace black, channel black, lamp black, thermal black, Ketjen black, or graphene, but is not limited thereto, and any amorphous carbon that can be used in an all-solid-state battery may be used without limitation.

[0036] The carbon material may be included in an amount of 20% to 70% by weight based on the total weight of the cathode coating layer. For example, the carbon material may be included in an amount within a range consisting of one lower limit selected from 20 wt% or more, 21 wt% or more, 22 wt% or more, 23 wt% or more, 24 wt% or more, 25 wt% or more, 26 wt% or more, 27 wt% or more, 28 wt% or more, 29 wt% or more, 30 wt% or more, 35 wt% or more, 40 wt% or more, 45 wt% or more, 50 wt% or more, and 55 wt% or more, and one upper limit selected from 70 wt% or less, 69 wt% or less, 68 wt% or less, 67 wt% or less, 66 wt% or less, 65 wt% or less, 64 wt% or less, 63 wt% or less, 62 wt% or less, 61 wt% or less, and 60 wt% or less, based on the total weight of the cathode coating layer.

[0037] When the content of the carbon material satisfies the above range, the lifespan characteristics and / or electrochemical performance of the all-solid-state battery can be improved.

[0038] The above lithium-affinity material includes a material capable of forming an alloy or compound with lithium, and may include an element capable of forming an alloy or compound with lithium.

[0039] The above lithium-affinity material may include one or more lithium-affinity elements or lithium-affinity compounds. The above lithium-affinity elements may include one or more selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), cobalt (Co), zirconium (Zr), indium (In), magnesium (Mg), aluminum (Al), bismuth (Bi), tin (Sn), chromium (Cr), copper (Cu), tungsten (W), germanium (Ge), lead (Pb), antimony (Sb), or zinc (Zn).

[0040] The above lithium-affinity compound may include one or more selected from lithium carbonate, lithium titanate, or oxides, nitrides, halides, sulfides, carbides, hydrides, or hydroxides of the lithium-affinity element.

[0041] The above lithium-affinity material may include one or more lithium-affinity elements or lithium-affinity compounds, and the lithium-affinity element may be one or more selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), cobalt (Co), zirconium (Zr), indium (In), magnesium (Mg), aluminum (Al), bismuth (Bi), tin (Sn), chromium (Cr), copper (Cu), tungsten (W), germanium (Ge), lead (Pb), antimony (Sb), or zinc (Zn), and the lithium-affinity compound may be one or more selected from lithium carbonate, lithium titanate, or oxides, nitrides, halides, sulfides, carbides, hydrides, or hydroxides of the lithium-affinity element.

[0042] The lithium-affinity material may include a metal of the lithium-affinity element. The lithium-affinity material may include an alloy of the lithium-affinity element. Alternatively, the lithium-affinity material may include one or more compounds selected from oxides, nitrides, halides, sulfides, carbides, hydrides, or hydroxides of the lithium-affinity element.

[0043] The above lithium-affinity material may include an alloy of the above lithium-affinity element, and an alloy of lithium and the above lithium-affinity element (Li-M 1 alloy), alloy of other metallic elements and the above lithium affinity element (M 1 -M 2 It may include two or more alloys selected from the above lithium affinity elements), or, but is not limited thereto. For example, Si-M 2 Alloy (M 2 is an alkali metal, alkaline earth metal, Group 13 element, Group 14 element, transition metal, rare earth element, or combination thereof, but is not Si) or Sn-M 2 Alloy (M 2may include alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, transition metals, rare earth elements, or combinations thereof (but not Sn), etc. The above M 2 may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof, and said M 1 It may be gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), cobalt (Co), zirconium (Zr), indium (In), magnesium (Mg), aluminum (Al), bismuth (Bi), tin (Sn), chromium (Cr), copper (Cu), tungsten (W), germanium (Ge), lead (Pb), antimony (Sb), zinc (Zn), or a combination thereof.

[0044] When including a lithium-affinity material as described above, it has the effect of suppressing lithium dendrite formation by lowering the lithium nucleation energy when lithium or lithium alloy is deposited or plated during charging and discharging.

[0045] The particle size of the lithium-affinity material 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 material 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.

[0046] The lithium-affinity material may be included in an amount of 10% to 30% by weight based on the total weight of the cathode coating layer. For example, the lithium-affinity material may be included in an amount within a range consisting of one lower limit selected from 10% or more, 11% or more, 12% or more, 13% or more, 14% or more, 15% or more, 16% or more, 17% or more, 18% or more, 19% or more, 20% or more, 21% or more, 22% or more, 23% or more, and 24% or more, and one upper limit selected from 30% or less, 29% or less, 28% or less, 27% or less, and 26% or less, based on the total weight of the cathode coating layer. When the content of the above lithium-affinity material satisfies the above range, the life characteristics and / or electrochemical performance of the all-solid-state battery may be improved.

[0047] The carbon material and the lithium-affinity material may be included in the cathode coating layer in a weight ratio of 3:1 to 1:1, but are not limited thereto. For example, the weight ratio of the carbon material and the lithium-affinity material may be 3:1 to 1:1, 2.9:1 to 1:1, 2.8:1 to 1:1, or 2.7:1 to 1:1, or 3:1 to 1:1, or 3:1 to 1.2:1. Specifically, the weight ratio of the carbon material and the lithium-affinity material may be 2.9:1 to 1.1:1, 2.8:1 to 1.2:1, or 2.5:1 to 1:1, or 2.5:1 to 1.5:1. In this specification, the present invention provides a negative electrode coating layer that includes a carbon material and a lithium-affinity material in the weight ratio as described above, thereby suppressing the formation of lithium dendrites by ensuring that lithium is uniformly deposited and grown on the surface of the negative electrode current collector, and as a result, can provide an all-solid-state battery with excellent discharge capacity characteristics.

[0048] The above zeolite is a general term for crystalline aluminosilicate minerals of alkali and alkaline earth metals, and can be classified into various types based on commonalities in water content, crystal properties, and acid phases. The above zeolite is a crystalline molecular sieve of alumina-silica having a regular three-dimensional skeletal structure in which tetrahedra of SiO4 and AlO4 are bonded in a stereonetic form; the tetrahedra are connected by sharing oxygen, and the skeleton contains channels (also known as pores or voids) and may be a type of porous inorganic material having interconnected cavities. The above zeolite has the general molecular formula M x / n [(AlO2) x (SiO2) y] can have zH2O, where n is the charge of the metal cation (M), and M is usually the sodium ion (Na + ), potassium ions (K + ) or calcium ions (Ca 2+ ) can be, x and y can be any integers, and z can be the number of moles of highly variable hydrated water molecules. The zeolite may have the property of selectively and strongly adsorbing polar substances through the action of metal cations within its crystal structure.

[0049] As described above, by applying a zeolite having porous, adsorption, and / or ion exchange properties to the cathode coating layer of the present invention, residual moisture within the all-solid-state battery can be captured, adsorbed, or absorbed, thereby improving the battery's lifespan characteristics. In particular, capturing, adsorbing, or absorbing gases such as hydrogen sulfide generated during the operation of the all-solid-state battery helps to improve the battery's lifespan characteristics.

[0050] The above zeolite may be used without special restrictions as long as it is capable of adsorbing gases such as moisture and / or hydrogen sulfide. For example, the above zeolite may be a natural zeolite or a synthetic zeolite.

[0051] The above natural zeolite may include at least one selected from anlcime, natrolite, stilbite, chabazite, clinoptilolite, heulandite, phillipsite, or mordenite, and the above synthetic zeolite may include at least one selected from type A, type X, type Y, type L, type β, or ZSM-5, but is not limited thereto.

[0052] The content of the zeolite may be included in the cathode coating layer in an amount of 5% to 55% by weight based on the total weight of the cathode coating layer, but is not limited thereto. For example, the content of the zeolite is one lower limit selected from 5 wt% or more, 5.5 wt% or more, 6 wt% or more, 6.5 wt% or more, 7 wt% or more, 7.5 wt% or more, 8 wt% or more, 8.5 wt% or more, 9 wt% or more, 9.5 wt% or more, 10 wt% or more, 11 wt% or more, 12 wt% or more, 13 wt% or more, 14 wt% or more, 15 wt% or more, 16 wt% or more, 17 wt% or more, and 18 wt% or more, based on the total weight of the cathode coating layer, and 55 wt% or less, 54 wt% or less, 53 wt% or less, 52 wt% or less, 51 wt% or less, 50 wt% or less, 49 wt% or less, 48 ​​wt% or less, 47 wt% or less, 46 wt% or less, 45 wt% or less, 40 wt% or less, 35 A range consisting of one upper limit selected from weight% or less, 30 weight% or less, 25 weight% or less, and 20 weight% or less may be satisfied. For example, it may be included in the cathode coating layer in an amount of 5 weight% to 50 weight%, 7 weight% to 45 weight%, 7.5 weight% to 45 weight%, 10 weight% to 40 weight%, or 15 weight% to 30 weight%. When the content of the zeolite satisfies the above range, the gas adsorption capacity of the zeolite, such as moisture and / or hydrogen sulfide, may be improved, thereby improving the lifespan characteristics of the all-solid-state battery and improving electrochemical performance.

[0053] The average particle size of the zeolite may be 0.1 μm to 5 μm, but is not limited thereto. For example, the average particle size of the zeolite may be 0.1 μm to 5 μm, 0.3 μm to 4.8 μm, 0.5 μm to 4.6 μm, 0.7 μm to 4.4 μm, 0.9 μm to 4.2 μm, 1.1 μm to 4 μm, 1.3 μm to 3.8 μm, 1.5 μm to 3.6 μm, 1.7 μm to 3.4 μm, 1.9 μm to 3.2 μm, 2.1 μm to 3 μm, 2.3 μm to 2.8 μm, or 2.5 μm to 2.6 μm. If the average particle size of the above zeolite satisfies the above range, gases such as moisture and / or hydrogen sulfide can be effectively captured, thereby improving the lifespan characteristics or electrochemical performance of the all-solid-state battery.

[0054] The zeolite may include pores ranging from 0.1 nm to 10 nm, but is not limited thereto. For example, the zeolite may include pores ranging from 0.1 nm to 10 nm, 0.5 nm to 9.5 nm, 1 nm to 9 nm, 1.5 nm to 8.5 nm, 2 nm to 8 nm, 2.5 nm to 7.5 nm, 3 nm to 7 nm, 3.5 nm to 6.5 nm, 4 nm to 6 nm, or 4.5 nm to 5.5 nm. When the pores of the zeolite satisfy the above ranges, gases such as moisture and / or hydrogen sulfide are easily adsorbed by effectively binding to the pores of the zeolite, thereby improving the lifespan characteristics of the all-solid-state battery and enhancing electrochemical performance.

[0055] The carbon material and the zeolite may be included in the cathode coating layer in a weight ratio of 0.5:1 to 10:1, but are not limited thereto. For example, the weight ratio of the carbon material and the zeolite may be 0.5:1 to 10:1, 0.6:1 to 9.5:1, 0.66:1 to 9:1, or 1:1 to 10:1, 1:1 to 9:1, 1.5:1 to 9:1, 2.5:1 to 9:1, 3:1 to 9:1, or 3.5:1 to 9:1. When the weight ratio of the carbon material and the zeolite satisfies the above range, the gas adsorption capacity of the zeolite, such as moisture and / or hydrogen sulfide, can be improved, thereby improving the lifespan characteristics of the all-solid-state battery and improving electrochemical performance.

[0056] The above cathode coating layer may further include, for example, a binder. For example, a water-based binder, an organic binder, or a combination thereof may be used as the binder. The binder may include, for example, polyvinyl alcohol, carboxymethylcellulose (CMC), hydroxypropylcellulose, diacetylcellulose, polyvinylidene fluoride (PVdF), polyvinyl chloride (PVC), carboxylated polyvinyl chloride, polyvinyl fluoride (PVF), ethylene oxide-based polymer, polyvinylpyrrolidone (PVP), polyurethane, polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), styrene-butadiene rubber (SBR), acrylate-based SBR, epoxy resin, nylon, or a combination thereof. For example, SBR, CMC, or a combination thereof can be used as a water-based binder, and PTFE, PVdF, or a combination thereof can be used as an organic binder.

[0057] The above cathode coating layer may contain, for example, 1 to 20 weight percent of a binder. By including the binder in such a range, the adhesion between the cathode current collector and the non-cathode coating layer described later, and / or between the materials included in the non-cathode coating layer, can be improved.

[0058] The above-mentioned cathode coating layer may further include, for example, other additives. As long as it does not impede the purpose of the present invention, fillers, coating agents, dispersants, ion conductivity aids, etc., commonly used in all-solid-state batteries may be used without limitation.

[0059] The cathode coating layer of the present invention may further include, for example, a solvent. In this specification, the meaning of the non-cathode coating layer further including a solvent may mean that a solvent is used during the manufacturing process of the non-cathode coating layer, and may not mean that the non-cathode coating layer finally manufactured through drying, etc., contains a solvent. Water, N-methylpyrrolidone (NMP), etc., may be used as the solvent.

[0060] The above-described cathode coating layer absorbs lithium during charging, and after the charging capacity of the cathode coating layer is exceeded, lithium is precipitated between the cathode current collector and the cathode coating layer to form a metal layer containing lithium metal or a lithium alloy; during discharge, it can serve to cause the lithium in the cathode coating layer and / or the metal layer to ionize and move toward the anode. The above-described cathode coating layer refers to a layer formed between the cathode current collector and the solid electrolyte layer, and its composition and operating mechanism may differ from conventional cathode active material layers. The above-described cathode coating layer can cover the metal layer containing lithium metal or a lithium alloy formed on the cathode current collector during the charging process, thereby acting as a protective layer for the metal layer and suppressing the growth of lithium dendrites. Through this, short circuits and capacity degradation of the all-solid-state battery can be suppressed, and performance, etc., can be improved. The above-described cathode coating layer may include a non-cathode coating layer.

[0061] The density of the above cathode coating layer is 0.1 g / cm³ 3 Up to 10 g / cm 3 It may be, but is not limited thereto. For example, the density of the cathode coating layer is 0.1 g / cm³ 3 Up to 10 g / cm 3 , 0.2 g / cm 3 Up to 9 g / cm² 3 , 0.3 g / cm 3 Up to 8 g / cm² 3 , 0.4 g / cm 3 Up to 7 g / cm² 3 , 0.5 g / cm 3 Up to 6 g / cm² 3 , 0.6 g / cm 3 Up to 5 g / cm² 3 , 0.1 g / cm 3 Up to 5 g / cm² 3 , 0.1 g / cm 3 Up to 3 g / cm² 3 or 0.1 g / cm³ 3 Up to 1 g / cm 3It may be possible. If the density of the above-mentioned cathode coating layer satisfies the above range, the lifespan characteristics of the all-solid-state battery can be improved and the electrochemical performance can be improved.

[0062] A second aspect of the present invention relates to an all-solid-state battery comprising the negative electrode coating layer.

[0063] The details regarding the first aspect of the present invention may be applied in the same way to the details regarding the second aspect unless specifically described otherwise.

[0064] In this specification, the term "all-solid-state battery" may refer to an all-solid-state secondary battery and may also be referred to as a cell, monocell, bicell, secondary battery, or battery.

[0065] The all-solid-state battery of the present invention may be characterized by comprising a positive electrode; a solid electrolyte layer; and a negative electrode comprising a negative electrode coating layer according to a first embodiment.

[0066] The above anode may include, for example, an anode current collector and an anode active material layer formed on at least one surface of the anode current collector.

[0067] The above positive current collector may include a known metal that can be used as a current collector for an all-solid-state battery. The above positive current collector may include, 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 above positive current collector may be omitted in some cases.

[0068] The above positive current collector may have a thickness of 5 μm to 300 μm, and fine irregularities may be formed on the surface of the positive current collector to increase the adhesion of the positive active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0069] The above positive active material layer may include, for example, a positive active material, a solid electrolyte, a binder and / or a conductive material.

[0070] The above-mentioned positive electrode active material reversibly absorbs and desorbs lithium ions. The positive electrode active material may be, for example, 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 manganese oxide (lithium manganate), and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide, but is not limited thereto; any material used as a positive electrode active material in the relevant technical field may be used. The positive electrode active material may be used individually or in a mixture of two or more types.

[0071] The above lithium transition metal oxide is, for example, Li a A 1-b B b D2 (wherein 0.90≤a≤1, and 0≤b≤0.5); Li a Ni 1-b-c Co b B c O 2-α F2(wherein 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 Dα (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(wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a MnG b O2(wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Mn2GbO4 (wherein the above formula, 0.90≤a≤1, 0.001≤b≤0.1); Li a Ni 1-b-c Mn 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 Ni 1-b-c Mn b B c O 2-α F2(wherein 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni b Ec G d O2(wherein 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 (wherein 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 (wherein the above equation, 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 such a 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; and J may be V, Cr, Mn, Co, Ni, Cu, or a combination thereof. As a positive electrode active material, a compound having a coating layer added to the surface of such a compound may be used, or a mixture of the compound described above and the compound having a coating layer added may be used. A coating layer added to the surface of such compounds may contain, for example, a lithium ion conductive oxide. The lithium ion conductive oxide is, for example, LiNbO3, Li4Ti5O 12Examples include Li3PO4, but are not limited thereto. The compounds forming this coating layer may be amorphous or crystalline. Methods for forming the coating layer may include, for example, spray coating or immersion methods, but can be selected without limitation as long as they do not adversely affect the physical properties of the cathode active material.

[0072] When the above-mentioned positive electrode 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 the metal leaching of the positive electrode active material in the charged state. Accordingly, the cycle characteristics of the all-solid-state battery in the charged state may be improved.

[0073] The shape of the above-mentioned positive active material may be, for example, a particle shape such as a sphere, ellipse, or sphere. The particle size of the positive active material is not particularly limited and must be within a range applicable to the positive active material of a conventional all-solid-state secondary battery. The content of the positive active material of the positive is also not particularly limited and must be within a range applicable to the positive of a conventional all-solid-state secondary battery.

[0074] The solid electrolyte included in the above-mentioned positive electrode active material layer may be the same as or different from the solid electrolyte included in the solid electrolyte layer described below, for example. The solid electrolyte included in the above-mentioned positive electrode active material layer may be a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a phosphoric acid-based solid electrolyte, or a halide-based solid electrolyte, but is not limited thereto and may be any that is commonly used in all-solid-state batteries.

[0075] The binder included in the above-mentioned positive active material layer serves to improve adhesion between positive active material particles and adhesion between the positive active material and the positive current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol (PVA), polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone (PVP), polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these alone or a mixture of two or more may be used. The binder may be included in an amount of 0.1% to 30% by weight, 0.1% to 20% by weight, or 0.1% to 10% by weight based on the total weight of the positive electrode active material layer.

[0076] The conductive material included in the above positive active material layer is used to impart conductivity to the electrode, and can be used without special restrictions as long as it has electronic conductivity without causing chemical changes. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, or silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more may be used. The above conductive material may be included in an amount of 0.1% to 30% by weight, 0.1% to 20% by weight, or 0.1% to 10% by weight based on the total weight of the above positive active material layer.

[0077] In addition to the above, the positive active material layer may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids, and these additives may be used without limitation as long as they are known materials generally used in electrodes of all-solid-state batteries.

[0078] The above solid electrolyte layer may include, but is not limited to, sulfide-based solid electrolytes, oxide-based solid electrolytes, polymer-based solid electrolytes and / or halide-based solid electrolytes.

[0079] The above sulfide-based solid electrolyte contains sulfur atoms (S) and can have ionic conductivity of metals belonging to Group 1 or Group 2 of the periodic table while possessing electronic insulation properties. Generally, it contains at least lithium (Li), sulfur (S), and phosphorus (P) as elements, and it is preferable to have lithium ion conductivity, but in some cases, it may contain elements other than Li, S, and P.

[0080] The above sulfide-based solid electrolyte may be, for example, one or more of the following compositions:

[0081] Li2S-P2S5, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, SiS2-B2S3-LiI, Li2S-SiS2-Li4SiO4, 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-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) or Li 10 GeP2S 12 .

[0082] The above sulfide-based solid electrolyte may also include, for example, a compound with an argyrodite structure, and for example, Li (6-x) PS (5-x) Cl (1+x-y) Br (y) (0 <x<0.6, 0<y<0.4), Li 7-x PS6-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), etc. may be included. In particular, an azirodite-based solid electrolyte comprising one or more of Li6PS5F, Li6PS5Cl, Li6PS5Br, Li6PS5I, or Li6PS5X (where X is 2 or more selected from F, Cl, Br, and I) may be used.

[0083] These sulfide-based solid electrolytes can be manufactured by processing starting materials, such as Li2S or P2S5, using a melt quenching method or a mechanical milling method, and additional heat treatment may be performed after such processing. The manufactured solid electrolyte may be in an amorphous state, a crystalline state, or a mixed state thereof, and in some cases, may include glass ceramic obtained by heat treating sulfide glass.

[0084] In addition, the density of the azirodite-based solid electrolyte may be, for example, 1.5 to 2.0 g / cc, and if the density is 1.5 g / cc or higher, it can reduce internal resistance within the all-solid-state secondary battery and effectively suppress penetration of the solid electrolyte by lithium.

[0085] The elastic modulus of the above sulfide-based solid electrolyte may be, for example, in the range of 15 to 35 GPa. The elastic modulus may be measured through a stress-strain curve, but is not limited thereto.

[0086] The above oxide-based solid electrolyte may be a material containing oxygen (O) and having the ionic conductivity of a metal belonging to Group 1 or Group 2 of the periodic table. The oxide-based solid electrolyte may be, for example, in a crystalline, amorphous, glassy, ​​or glass-ceramic state, and may have various crystal structures depending on the manufacturing method and composition. Such oxide-based solid electrolytes may include, for example, LLZO-based compounds, LLTO-based compounds, LIPON-based compounds, LISICON-based compounds, NASICON-based compounds, or perovskite-based compounds. More specifically, Li7La3Zr2O 12 , Li 3+x La3M2O 12 (M is Te, Nb, or Zr, 1≤x≤10), Li 3+x La3Zr 2-a M a O 12 (M is Ga, W, Nb, Ta, or Al, 0 <a<2, 1≤x≤10), Li 1+x Al x Ti 2-x (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 1+x Al x Ge 2-x (PO4)3(0 <x<2), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), LiSiO2TiO2(PO4)3(LSTP), Li 3x La(2 / 3-x)(1 / 3-2x)TiO3(0.04 <x<0.16), LiAl x Zr 2-x (PO4)3(0≤x≤1, 0≤y≤1), LiTi x Zr 2-x (PO4)3(0≤x≤1, 0≤y≤1), Li x Ti y (PO4)3(0 <x<2, 0<y<3), Lix Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<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), Li x La y TiO3(0 <x<2, 0<y<3) 등이 있다. 그 밖에도 Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M is Te, Nb, or Zr, 1≤x≤10), Li6La2CaTa2O 12 , Li6La2ANb2O 12 (A is Ca or Sr), Li2Nd3TeSbO 12 , Li3BO 2.5 N 0.5 , Li9SiAlO8, BaTiO3, Pb(Zr, Ti)O3, Pb 1-x La x Zr 1-y Ti y O3(0≤x<1, 0≤y<1), Pb(Mg 1 / 3 Nb 2 / 3 O3-PbTiO3, HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, etc. can also be exemplified as constituent compositions of oxide-based solid electrolytes.

[0087] The above-mentioned polymer-based solid electrolyte is a polymer material exhibiting ion conductivity, generally in the form of a composite of a lithium salt and a polymer resin. That is, it is an electrolyte formed by adding a polymer resin to a solvated lithium salt, approximately 1 × 10⁻⁶ -7 S / cm or more, or about 1×10 -5It can exhibit ionic conductivity of S / cm or higher. Usable polymer resins may include polyether-based, polycarbonate-based, acrylate-based, polysiloxane-based, and phosphazene-based polymers, polyethylene derivatives, polyethylene oxide (PEO) and its derivatives, alkylene oxide derivatives, phosphate ester polymers, polyaisation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and polymers containing ionic dissociators. In particular, it can also be used in the form of branched copolymers, comb-like polymers, or cross-linked polymer resins, which are formed by copolymerizing amorphous polymers such as PMMA, polycarbonate, polysiloxane, and phosphazene as comonomers with a PEO main chain. The lithium salt used in conjunction with this is Li + X - It is an ionizable lithium salt of the form, and as an anion, it is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - , (CF3CF2SO2)2N- Various types of negative ions can be used.

[0088] The above-mentioned halide-based solid electrolyte is an electrolyte containing a halogen element as the main component of the anion, wherein "main component" means that the halogen element accounts for the highest molar ratio among the anions in the electrolyte. The halogen content may be 50 mol% or more, 70 mol% or more, 90 mol% or more, or up to 100 mol% or more of the total anions, and may include one or more of F, Cl, Br, and I. The halide-based solid electrolyte may not typically contain sulfur (S) elements, and may include lithium (Li) and metal elements (M; e.g., Sc, Y, B, Al, Ga, In, etc.) as cations, and halogens (X) as anions. An example of the composition is Li 6-3a M a Br b Cl c (M is a metal other than Li, and 0 <a<2, 0≤b≤6, 0≤c≤6, b+c=6), Li3YBr6, Li3YCl6, 또는 Li3YBr2Cl4등이 있을 수 있다.

[0089] The shape of the solid electrolyte included in the solid electrolyte layer above may be particulate. In addition, the average particle size (D) of the solid electrolyte particles above. 50 The thickness may be 0.5 μm to 4 μm. The solid electrolyte may be used as a single type or as two or more types. If the solid electrolyte layer contains two or more types of solid electrolytes, it may include a form in which two or more types of solid electrolytes are mixed in one layer, or a multilayer structure may be included by forming separate layers containing each solid electrolyte, or a multilayer structure may be included by mixing each solid electrolyte and forming separate layers with the same or different mixing ratios.

[0090] The solid electrolyte layer may include, for example, a binder. The binder included in the solid electrolyte layer may be, for example, one of the types of binders included in the positive active material layer, but is not limited to these, and any binder used in the relevant technical field may be possible. The binder included in the solid electrolyte layer may be the same as or different from the binder included in the aforementioned positive active material layer and / or non-cathode coating layer. The solid electrolyte layer may include, for example, 10 weight percent or less of the binder.

[0091] The thickness of the solid electrolyte layer may be, for example, 100 μm or less. In other examples, the thickness of the solid electrolyte layer may be 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, or 50 μm or less, or 1 μm or more, 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, 8 μm or more, 9 μm or more, or 10 μm or more, but is not limited thereto. When the thickness of the solid electrolyte layer satisfies the above range, the function as a separator can be sufficiently performed and the deterioration of mechanical properties during charging and discharging can be prevented.

[0092] The above-mentioned cathode may include a cathode current collector and a cathode coating layer according to the first embodiment. The above-mentioned cathode may be a cathode for an anodeless battery in which a cathode active material layer, such as a lithium metal layer, is formed through battery charging, and the cathode active material layer does not include a cathode active material layer immediately after battery manufacturing or after discharge.

[0093] The above-mentioned negative electrode current collector may include known metals that can be used as current collectors for all-solid-state batteries. For example, the above-mentioned negative electrode current collector may use a material that does not form alloys or compounds with lithium. The above-mentioned negative electrode current collector may include, for example, 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), or 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 above-mentioned negative electrode current collector may be composed of one of the metals described above, or may be composed of an alloy of two or more metals or a coating material. The above-mentioned negative electrode current collector may be, for example, in the form of a plate, mesh, or foil, but is not limited thereto. The above-mentioned negative current collector may typically have a thickness of 1 μm to 500 μm, and may also form fine irregularities on the surface of the negative current collector to strengthen the bonding force of the negative active material.

[0094] The thickness of the above cathode coating layer may be 5 μm to 50 μm, but is not limited thereto. For example, the thickness of the cathode coating layer may satisfy a range consisting of one lower limit selected from 5 μm or more, 6 μm or more, 7 μm or more, 8 μm or more, 9 μm or more, and 10 μm or more, and one upper limit selected from 50 μm or less, 48 ​​μm or less, 46 μm or less, 45 μm or less, 44 μm or less, 42 μm or less, 40 μm or less, 38 μm or less, 36 μm or less, 35 μm or less, 34 μm or less, 32 μm or less, 30 μm or less, 28 μm or less, 26 μm or less, 25 μm or less, 24 μm or less, 22 μm or less, 20 μm or less, 18 μm or less, 16 μm or less, 15 μm or less, 14 μm or less, and 12 μm or less. By controlling the thickness of the above-mentioned cathode coating layer as described above, a lithium metal layer is uniformly deposited between the cathode coating layer and the cathode current collector, and the formation of lithium dendrites is suppressed, thereby improving battery life characteristics.

[0095] The loading amount of the above cathode coating layer is 0.1 mg / cm² 2 up to 5 mg / cm² 2 It may be, but is not limited thereto. For example, the loading amount of the cathode coating layer is 0.1 mg / cm² 2 Above, 0.2 mg / cm² 2 Above, 0.3 mg / cm² 2 Above, 0.4 mg / cm² 2 Above and 0.5 mg / cm² 2 One lower limit selected from the above, and 5 mg / cm² 2 Below, 4.8 mg / cm² 2 Below, 4.6 mg / cm² 2 Below, 4.4 mg / cm² 2 Below, 4.2 mg / cm² 2 ≤ 4 mg / cm² 2 Below, 3.8 mg / cm² 2 Below, 3.6 mg / cm² 2 Below, 3.4 mg / cm²2 Below, 3.2 mg / cm² 2 Below and 3 mg / cm² 2 It may satisfy a range consisting of one upper limit selected from the following. For example, 0.1 mg / cm² 2 up to 5 mg / cm² 2 , 0.3 mg / cm 2 Up to 4 mg / cm² 2 , 0.5 mg / cm 2 to 3 mg / cm² 2 It is possible. By controlling the loading amount of the above-mentioned cathode coating layer as described above, a lithium metal layer can be uniformly deposited between the cathode coating layer and the cathode current collector, and the formation of lithium dendrites can be suppressed, thereby improving battery life characteristics.

[0096] The above-mentioned cathode may further comprise, for example, a metal and / or a metal layer containing lithium or a lithium alloy between the cathode current collector and the cathode coating layer and / or within the cathode coating layer upon charging. The lithium alloy may be, for example, Li-Al alloy, Li-Sn alloy, Li-In alloy, Li-Ag alloy, Li-Au alloy, Li-Zn alloy, Li-Ge alloy, or Li-Si alloy, but is not limited thereto; any alloy used as a lithium alloy in the relevant technical field is acceptable. The metal or metal layer included between the cathode current collector and the cathode coating layer and / or within the cathode coating layer may be composed of one of these alloys or lithium, or may be composed of various types of alloys.

[0097] The thickness of the metal layer containing the lithium or lithium alloy may be, for example, within a range of 1 to 100 μm, 1 to 90 μm, 1 to 80 μm, 1 to 70 μm, 1 to 60 μm, 1 to 50 μm, 1 to 40 μm, or 1 to 30 μm. It is necessary to control the thickness as described above so that the metal layer can effectively perform its role as a lithium reservoir and improve cycle characteristics. The thickness of the metal layer can be controlled by adjusting the loading amount of the anode, but is not limited thereto and can be controlled by various factors within the battery.

[0098] The metal layer may be formed, for example, by precipitation between the negative current collector and the negative coating layer through charging after assembly of the all-solid-state battery described later. The metal layer may include a lithium layer. When a metal layer is formed between the negative current collector and the negative coating layer through charging after assembly of the all-solid-state battery, the negative current collector, the negative coating layer, and the region between them may be, for example, a lithium-free (Li-Free) region that does not contain lithium in the initial state or after discharge state of the all-solid-state battery.

[0099] The ratio (percentage) of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle of the all-solid-state battery according to the second embodiment may be characterized as being 93% or more, but is not limited thereto. For example, the ratio of the discharge capacity of the 100th cycle to the discharge capacity of the first cycle of the all-solid-state battery according to the second embodiment may be 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more.

[0100] In the following, the present invention is described in detail with reference to examples to specifically explain the disclosure of the present invention as described above and the intended functions and effects of the present invention. However, the examples may be modified in various different forms, and the scope of this specification is not to be interpreted as being limited only to these examples. It is emphasized that the examples are provided to represent the present invention and to explain it more specifically to those skilled in the art.

[0101] Examples and Comparative Examples

[0102] Example 1

[0103] (cathode)

[0104] 5.4g of amorphous carbon, 0.6g of zeolite, 2g of Ag, 9.33g of PVdF binder (solid content 6%), and 7.67g of NMP solution were placed in a Thinky mixer container and mixed 12 times for 3 minutes at 2,000 rpm. Afterwards, 5g of NMP solution was added and mixed 5 times for 3 minutes at 2,000 rpm to prepare a cathode active material slurry, which was then coated onto a SUS foil and dried at 100°C for 10 hours to produce a cathode.

[0105] (anode)

[0106] LiNi as the positive active material 0.8 Co 0.15 Mn 0.05 O2 (NCM), Li6PS5Cl, an argyrodite-type crystal, as the solid electrolyte, carbon nanofiber (CNF) as the conductive material, and polytetrafluoroethylene (Teflon binder, DuPont) as the binder were prepared. Then, these materials were mixed in a weight ratio of positive active material : solid electrolyte : conductive material : binder = 84 : 14.6 : 0.2 : 1.2, and then formed into a large sheet to produce a positive electrode sheet. Subsequently, the positive electrode sheet was pressed onto an 18 μm thick aluminum foil to produce a positive electrode.

[0107] (Solid electrolyte layer)

[0108] A solid electrolyte layer slurry was prepared by dispersing and stirring azirodite (Li6PS5Cl) as a solid electrolyte and polytetrafluoroethylene as a binder in an anisole at a weight ratio of 95:5. This was coated onto a polyethylene terephthalate release film and vacuum dried at 100°C for 12 hours to prepare a solid electrolyte layer.

[0109] (Monocell)

[0110] A monocell was manufactured by laminating the above anode, solid electrolyte layer, and anode, and sealing them in a pouch under vacuum.

[0111] Example 2

[0112] A monocell was manufactured in the same manner as in Example 1, except that a negative electrode for an all-solid-state battery was manufactured using 4.5g of amorphous carbon instead of 5.4g and 1.5g of zeolite instead of 0.6g.

[0113] Example 3

[0114] A monocell was manufactured in the same manner as in Example 1, except that a negative electrode for an all-solid-state battery was manufactured using 2.4g of amorphous carbon instead of 5.4g and 3.6g of zeolite instead of 0.6g.

[0115] Comparative Example 1

[0116] A monocell was manufactured in the same manner as in Example 1, except that 6g of amorphous carbon was used instead of 5.4g in Example 1, and a negative electrode for an all-solid-state battery was manufactured without including zeolite.

[0117] Comparative Example 2

[0118] A monocell was manufactured in the same manner as in Example 1, except that 4.5g of amorphous carbon was used instead of 5.4g of zeolite and 1.5g of zeolite was used instead of 0.6g of zeolite, and an anode for an all-solid-state battery was manufactured without containing Ag.

[0119] The content of amorphous carbon, zeolite, and Ag used in Examples 1 to 3 and Comparative Examples 1 and 2 is summarized and shown in Table 1 below.

[0120] Classification Amorphous Carbon (g) Zeolite (g) Ag (g) Example 15.4 0.62 Example 24.5 1.52 Example 32.4 3.62 Comparative Example 16 02 Comparative Example 24.5 1.50

[0121] Evaluation example

[0122] The monocells of Examples 1 to 3 and Comparative Examples 1 and 2 were operated under the following charge-discharge conditions at an operating voltage range of 4.25V-3.0V and a driving temperature of 60℃ to evaluate the cycle characteristics, and the results are shown in Table 2, Fig. 1 (comparison of Examples 1 to 3 and Comparative Example 1) and Fig. 2 (comparison of Example 2 and Comparative Example 2).

[0123] *Charging / Discharging Conditions: 0.33C, 4.25V, CC / CV Charging, 0.1C Cut-off / 0.33C, 3.0V, CC Discharging

[0124] Capacity Retention (%) @ 100 cycle Example 195.5 Example 296.4 Example 394.7 Comparative Example 192.4 Comparative Example 271.5

Claims

1. Carbon materials; lithium-affinity material; and Zeolite; A cathode coating layer comprising 2. In Paragraph 1, The above carbon material comprises at least one selected from natural graphite, artificial graphite, carbon black, acetylene black, furnace black, channel black, lamp black, thermal black, Ketjen black, carbon nanotubes, carbon nanofibers, fluorinated carbon, activated carbon, graphene, graphitized carbon fibers, low-crystallinity carbon, or high-crystallinity carbon, forming a cathode coating layer.

3. In Paragraph 1, The above lithium-affinity material comprises one or more lithium-affinity elements or lithium-affinity compounds, and The above lithium affinity elements are one or more selected from gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), cobalt (Co), zirconium (Zr), indium (In), magnesium (Mg), aluminum (Al), bismuth (Bi), tin (Sn), chromium (Cr), copper (Cu), tungsten (W), germanium (Ge), lead (Pb), antimony (Sb), or zinc (Zn). A cathode coating layer wherein the lithium-affinity compound is one or more selected from lithium carbonate, lithium titanate, or oxides, nitrides, halides, sulfides, carbides, hydrides, and hydroxides of the lithium-affinity element.

4. In Paragraph 1, A cathode coating layer in which the content of the zeolite is 5% to 55% by weight based on the total weight of the cathode coating layer.

5. In Paragraph 1, Average particle size (D of the above zeolite) 50 A cathode coating layer having a thickness of 0.1 μm to 5 μm.

6. In Paragraph 1, The above zeolite is a cathode coating layer comprising pores of 0.1 nm to 10 nm.

7. In Paragraph 1, A cathode coating layer comprising the carbon material and the zeolite in a weight ratio of 0.5:1 to 10:

1.

8. Anode; Solid electrolyte layer; and A cathode comprising a cathode coating layer according to any one of claims 1 to 7; All-solid-state battery including 9. In Paragraph 8, The above solid electrolyte layer comprises at least one selected from a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer-based solid electrolyte, or a halide-based solid electrolyte, in an all-solid-state battery.

10. In Paragraph 9, The sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-H2S, Li2S-P2S5-H2S-LiCl, Li2S-LiI-P2S5, Li2S-LiI-Li2O-P2S5, Li2S-LiBr-P2S5, Li2S-Li2O-P2S5, Li2S-Li3PO4-P2S5, Li2S-P2S5-P2O5, Li2S-P2S5-SiS2, Li2S-P2S5-SiS2-LiCl, Li2S-P2S5-SnS, Li2S-P2S5-Al2S3, Li2S-GeS2, Li2S-GeS2-ZnS, Li2S-Ga2S3, Li2S-GeS2-Ga2S3, Li2S-GeS2-P2S5, Li2S-GeS2-Sb2S5, Li2S-GeS2-Al2S3, Li2S-SiS2, Li2S-Al2S3, Li2S-SiS2-Al2S3, Li2S-SiS2-P2S5, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, SiS2-B2S3-LiI, Li2S-SiS2-Li4SiO4, 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-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), Li 10 GeP2S 12 , 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 All-solid-state battery comprising at least one selected from (0≤x≤2).

11. In Paragraph 8, An all-solid-state battery having a negative electrode coating layer thickness of 5 μm to 50 μm.

12. In Paragraph 8, The loading amount of the above cathode coating layer is 0.1 mg / cm² 2 up to 5 mg / cm² 2 Phosphorus, all-solid-state battery.

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