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

Abstract

The present invention relates to a negative electrode for an all solid-state battery and an all solid-state battery including same, the negative electrode comprising: a current collector; a first layer which is positioned on the current collector and is composed of an oxide of a metal that can be alloyed with lithium and a first binder; and a second layer which is positioned on the first layer and is composed of a carbon-based material and a second binder.

Description

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

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

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

[0003] Development of all-solid-state batteries using lithium metal as the cathode is underway. All-solid-state batteries are composed entirely of solid materials, specifically those using solid electrolytes. Because the electrolyte is solid, all-solid-state batteries are structurally robust, reducing the risk of fire or explosion due to leakage from external impacts. Furthermore, they can be shaped into a variety of battery shapes.

[0004] One embodiment provides an economical all-solid-state battery cathode exhibiting excellent electrochemical properties.

[0005] Another embodiment provides an all-solid-state battery comprising the above negative electrode.

[0006] One embodiment provides an anode for an all-solid-state battery, comprising: a current collector; a first layer positioned on the current collector and composed of an oxide of a metal capable of alloying with lithium and a first binder; and a second layer positioned on the first layer and composed of a carbon-based material and a second binder.

[0007] Another embodiment provides an all-solid-state battery comprising the cathode, the anode, and a solid electrolyte positioned between the cathode and the anode.

[0008] An all-solid-state battery cathode according to one embodiment exhibits excellent electrochemical properties and is economical.

[0009] Figure 1 is a schematic drawing of an all-solid-state battery negative electrode according to one embodiment.

[0010] Figure 2 is a cross-sectional view schematically showing an all-solid-state battery according to one embodiment.

[0011] Figure 3 is a cross-sectional SEM photograph of the cathode and solid electrolyte layer of Example 1.

[0012] Figure 4 is a cross-sectional SEM photograph of the cathode and solid electrolyte layer of Comparative Example 1.

[0013] Figure 5 is a cross-sectional SEM photograph of the cathode and solid electrolyte layer of Comparative Example 2.

[0014] Figure 6 is a graph showing the coulombic efficiency of half cells of Example 1 and Comparative Examples 1 and 2.

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0016] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0017] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0018] It should be understood that the terms "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0019] Throughout this specification, when it is said that a part "includes" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0020] In addition, the terms "about", "substantially", etc. used throughout this specification are used in the sense of numerical values ​​or near numerical values ​​when manufacturing and material tolerances inherent to the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures that mention exact or absolute values ​​to aid understanding of this specification.

[0021] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0022] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there is another part in between.

[0023] In the present invention, "particle size" or "particle diameter" may be an average particle diameter. In addition, the average particle diameter may be defined as the average particle diameter (D50) based on 50% of the cumulative volume in a particle diameter distribution curve. The particle diameter may be measured by a method widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope, a scanning electron microscope, or a field emission scanning electron microscope (FE-SEM). Alternatively, the average particle diameter (D50) may be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from this. Alternatively, the average particle diameter (D50) may be measured using a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle diameter (D50) based on 50% of the particle diameter distribution in the measuring device can be calculated.

[0024] "Thickness" may be measured, for example, from photographs taken with an optical microscope such as a scanning electron microscope.

[0025] An anode for an all-solid-state battery according to one embodiment includes: a current collector; a first layer positioned on the current collector and composed of an oxide of a metal capable of alloying with lithium and a first binder; and a second layer positioned on the first layer and composed of a carbon-based material and a second binder.

[0026] FIG. 1 schematically illustrates the structure of a cathode (400) according to one embodiment, wherein the cathode (400) includes a current collector (401), a first layer (403), and a second layer (405).

[0027] According to one embodiment, the negative electrode of the all-solid-state battery may be a precipitation-type negative electrode. A precipitation-type negative electrode is a negative electrode in which lithium ions released from a positive electrode active material move toward the negative electrode during battery charging and discharging, causing lithium precipitation on the surface of a current collector. For example, a lithium precipitation layer is formed between a current collector and a negative electrode coating layer due to the precipitation of lithium ions, and the lithium precipitation layer can function as a negative electrode active material. The oxides of metals capable of alloying with lithium and carbon-based materials do not function as negative electrode active materials that directly participate in charge and discharge reactions. When assembling such a battery, it refers to an negative electrode in which the lithium precipitation layer functions as a negative electrode active material, but does not include a negative electrode active material.

[0028] The first layer is composed of an oxide of a metal capable of being alloyed with lithium and a first binder. The oxide of the metal capable of being alloyed with lithium may be ZnO, SnO2(Ⅳ), SnO(Ⅱ), Bi2O3, or a combination thereof.

[0029] The oxide of the metal capable of alloying with lithium, when reacted with lithium, irreversibly forms a lithium oxide, such as Li2O, with the metal. Subsequently, the metal may further react with lithium, reversibly forming an alloy phase and decomposing the lithium and metal. This reaction, for example, when the metal is Zn, is expressed by the following reaction formula.

[0030] [Reaction Formula 1]

[0031] ZnO+2Li→Zn+2Li2O

[0032] [Reaction Formula 2]

[0033] Zn+Li↔Li-Zn

[0034] In one embodiment, the oxide of a metal capable of alloying with lithium is positioned in a separate layer from the carbon-based material. For example, the oxide of a metal capable of alloying with lithium is included in a first layer positioned on a current collector, and the carbon-based material is included in a second layer positioned on the first layer.

[0035] Since the first layer located between the current collector and the second layer contains an oxide of a metal capable of alloying with lithium, when the all-solid-state battery is charged and discharged, lithium deposition may occur between the first layer and the second layer according to the above reaction formula 1, and a lithium deposit may be located. In addition, the reaction of the above reaction formula 2 may occur, and a lithium alloy phase may be located between the first layer and the second layer.

[0036] Since this reaction occurs between the first and second layers, which do not directly contact the solid electrolyte, direct contact between the lithium deposit and the solid electrolyte can be minimized, thereby preventing deterioration of the solid electrolyte. Furthermore, the influence of Zn, which forms an alloy phase with lithium, allows for stable lithium deposition, and since Li2O does not directly electrochemically react with lithium, the second layer structure can be maintained without change.

[0037] When lithium metal generated at the interface between the second layer containing amorphous carbon and the solid electrolyte migrates toward the current collector through creep deformation on the surface of the carbon particles, lithium can be uniformly deposited in a columnar shape on the surface of the current collector due to the lithium alloy phase formed in the first layer. Accordingly, a lithium deposition layer can be stably and uniformly formed on the current collector.

[0038] If the oxide of a metal that can be alloyed with lithium is located in the same layer as the carbon-based material, the lithium deposit cannot prevent contact with the solid electrolyte, which is not suitable. Moreover, in this case, in the initial cycle, lithium moves through creep deformation due to the influence of the carbon-based material, and the lithium deposit is deposited between the first layer and the current collector. However, as the cycle progresses, the pores of the carbon-based material become blocked, and the lithium deposit is located at the interface between the first and second layers. This change in the deposition location causes electrode instability, which is not suitable.

[0039] Additionally, if the cathode does not include a second layer containing a carbon-based material, the first layer may come into direct contact with the solid electrolyte layer, resulting in lithium deposition at the interface between the first layer and the solid electrolyte layer. In this case, the high reactivity of lithium and the solid electrolyte may accelerate deterioration of the solid electrolyte.

[0040] In addition, when an oxide of a metal that can be alloyed with lithium is included in the second layer rather than the first layer that comes into contact with the current collector, the lithium precipitate comes into direct contact with the solid electrolyte, making it inappropriate to prevent deterioration of the solid electrolyte.

[0041] The first layer is composed solely of two components: an oxide of a metal capable of alloying with lithium and a first binder. Furthermore, the second layer is composed solely of two components: a carbon-based material and a second binder. If the second layer includes a metal, such as silver, commonly used in deposition-type negative electrodes, it may inhibit the lithium alloying of the oxide of the metal capable of alloying with lithium contained in the first layer, making it unsuitable. Furthermore, as cycling progresses, lithium deposition occurs between the second layer and the solid electrolyte layer, making it impossible to prevent direct contact between the lithium and the solid electrolyte.

[0042] In one embodiment, the thickness ratio of the first layer and the second layer may be 1:1 to 1:10, or may be 1:1 to 1:7, or 1:1 to 1:5. When the thickness ratio of the first layer and the second layer is within the above range, the initial irreversible capacity can be minimized, and the stabilization of long-term battery life characteristics can be more effective.

[0043] The thickness of the first layer may be 1 µm to 10 µm, 1 µm to 5 µm, or 1 µm to 3 µm. In addition, the thickness of the second layer may be 1 µm to 10 µm, 2 µm to 7 µm, or 3 µm to 5 µm.

[0044] When the thickness ratio of the first layer and the second layer satisfies the above range, and the thicknesses of the first layer and the second layer each satisfy the above range, it is possible to minimize the initial irreversible capacity, help lithium to be deposited in a more stable shape, and minimize contact between lithium and the solid electrolyte layer.

[0045] In one embodiment, the content of the metal capable of alloying with lithium included in the first layer may be 80 wt% to 99 wt%, 85 wt% to 99 wt%, or 90 wt% to 99 wt%, based on 100 wt% of the total weight of the first layer. When the content of the metal capable of alloying with lithium is within the above range, the resistance caused by the first binder can be minimized, thereby more smoothly inducing an alloy phase formation reaction between the metal and lithium within the first layer.

[0046] In one embodiment, the content of the carbon-based material may be 80 wt% to 99 wt%, 85 wt% to 99 wt%, or 90 wt% to 99 wt%, based on 100 wt% of the total weight of the second layer. When the content of the carbon-based material is within the above range, the resistance caused by the second binder can be minimized, and creep deformation of the lithium metal can be more sufficiently induced, thereby minimizing direct contact between the solid electrolyte and lithium.

[0047] In one embodiment, the carbon-based material may be amorphous carbon.

[0048] The amorphous carbon may be, for example, carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, graphene, or a combination thereof. An example of the carbon black may be Super P (Timcal). The amorphous carbon is not limited thereto, and any material classified as amorphous carbon in the relevant field may be used.

[0049] In one embodiment, the amorphous carbon may be a single particle, or may be an assembly having a secondary particle form in which primary particles are assembled. When the amorphous carbon is a single particle, the size of the amorphous carbon may be a nano-size with an average particle diameter of 100 nm or less, for example, 10 nm to 100 nm.

[0050] Additionally, when the amorphous carbon is an assembly, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0051] In one embodiment, the particle size of the primary particles may be 20 nm to 100 nm, 20 nm to 90 nm, 20 nm to 80 nm, or 30 nm to 70 nm.

[0052] In one embodiment, the particle size of the secondary particles may be 1 μm to 20 μm, 2 μm to 15 μm, or 3 μm to 10 μm.

[0053] The shape of the primary particles may be spherical, elliptical, plate-shaped, or a combination thereof, and in one embodiment, the shape of the primary particles may be spherical, elliptical, or a combination thereof.

[0054] In one embodiment, the first binder and the second binder included in the first layer and the second layer, respectively, may be the same or different. The first binder and the second binder may be, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, or a combination thereof. The carboxymethyl cellulose, hydroxypropyl cellulose, or diacetyl cellulose may be an alkali metal salt thereof, and the alkali metal may be Na or Li. The first binder and the second binder are not limited to these, and any binder used in the art may be used.

[0055] The content of the first binder may be comprised in a range of 1 wt% to 20 wt%, 1 wt% to 15 wt%, or 1 wt% to 10 wt%, based on 100 wt% of the total weight of the first layer. Within the above content range, the first binder can sufficiently exhibit adhesive ability without deteriorating battery performance.

[0056] The content of the second binder may be comprised in an amount of 1 wt% to 20 wt%, 1 wt% to 15 wt%, or 1 wt% to 10 wt%, based on 100 wt% of the total weight of the second layer. Within the above content range, the second binder can sufficiently exhibit adhesive ability without deteriorating battery performance.

[0057] The current collector may be, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0058] The current collector may be formed of the metal as a substrate and may further include a thin film formed on the substrate. The thin film may include an element capable of forming an alloy with lithium, and may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, or a combination thereof, but is not limited thereto, and any element capable of forming an alloy with lithium in the art may be used. When the current collector further includes a thin film, when the lithium-containing layer is formed by precipitation during charging, a more planarized lithium-containing layer may be formed, thereby further improving the cycle life of the all-solid-state battery.

[0059] The thickness of the above thin film may be 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. When the thin film thickness is within the above range, the cycle life characteristics can be further improved.

[0060] According to one embodiment, the negative electrode may further include a lithium-containing layer formed during initial charging after battery manufacturing, between the current collector and the negative electrode coating layer. The thickness of the lithium-containing layer may be 1 µm to 1000 µm, 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 150 µm, 1 µm to 100 µm, or 1 µm to 50 µm. When the thickness of the lithium-containing layer is within the above range, the lithium storage function may be appropriately performed, and there may be an advantage of further improving the lifespan.

[0061] The lithium-containing layer can be formed when lithium ions are released from the positive electrode active material during charging after the battery is manufactured, pass through the solid electrolyte, and move toward the negative electrode, resulting in lithium being precipitated and deposited on the negative electrode current collector.

[0062] The above charging process may be a chemical reaction process performed once to three times at 0.05C to 1C at about 25°C to 50°C. When lithium is precipitated and deposited to form a lithium-containing layer, the lithium contained in the lithium-containing layer is ionized and moves toward the positive electrode during discharge, so that the lithium can be used as an anode active material.

[0063] All-solid-state battery

[0064] An all-solid-state battery according to one embodiment includes the cathode, the anode, and a solid electrolyte layer positioned between the cathode and the anode.

[0065] Solid electrolyte layer

[0066] In one embodiment, the solid electrolyte layer may include a solid electrolyte. It may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte. In one embodiment, the solid electrolyte may be a sulfide-based solid electrolyte. Such sulfide-based solid electrolytes are suitable because they have superior ion conductivity compared to other solid electrolytes such as oxide-based solid electrolytes, and can exhibit superior life characteristics over a wider operating range.

[0067] In one embodiment, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m and n are integers greater than or equal to 0 and less than or equal to 12, respectively, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are integers greater than or equal to 0 and less than or equal to 12, respectively; M is one of P, Si, Ge, B, Al, Ga In), Li a M b P c S d A e (a, b, c, d and e are each integers greater than or equal to 0 and less than or equal to 12, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I). The sulfide-based solid electrolyte may be, for example, Li 7-x PS 6-x F x (0≤x≤2), Li 7-x 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) can be. Also, specifically, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0068] In one embodiment, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The argyrodite-type sulfide-based solid electrolyte may be, for example, Li a M b P c S d A e (a, b, c, d, and e are all 0 or greater and 12 or less, M is Ge, Sn, Si, or a combination thereof, and A is one of F, Cl, Br, or I).

[0069] As specific examples, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li6PS5I, Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or a combination thereof, but is not limited thereto. The solid electrolyte may be β-phase or α-phase. For example, it may be β-Li3PS4.

[0070] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixture thereof. For example, the sulfide-based solid electrolyte may be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or in a molar ratio of 50:50 to 80:20. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0071] Methods for mixing sulfur-containing raw materials for manufacturing sulfide-based solid electrolytes include mechanical milling and solution methods. Mechanical milling involves placing the starting raw materials in a reactor and vigorously stirring them with a ball mill, thereby finely agitating the starting raw materials and mixing them. Using the solution method, the starting raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be manufactured by mixing sulfur-containing raw materials and heat-treating them twice or more, in which case a sulfide-based solid electrolyte with high ionic conductivity and robustness can be manufactured.

[0072] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0073] The above oxide-based solid electrolyte is, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), Pb(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-xSi y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr, x is an integer from 1 to 10), or a mixture thereof.

[0074] The above solid polymer electrolytes include, for example, polyethylene oxide, poly(diallyldimethylammonium)trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, and Li3PO. 4· Li2S · SiS2, Li2S · GeS 2· Ga2S3, Li2O · 11Al2O3, Na2O · 11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3(0.1≤x≤0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12, Li4NbP3O 12 , Li 1+x (M,Al,Ga) x (Ge 1-y Ti y ) 2-x (PO4)3(0≤x≤0.8, 0≤y≤1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), Li 1+x+y Q x Ti 2-x Si y P 3-y O 12 (0 <x≤ 0.4, 0<y≤0.6, Q 는 Al 또는 Ga), Li6BaLa2Ta2O 12 , Li7La3Zr2O 12 , Li5La3Nb2O 12 , Li5La3M2O 12 (M is Nb, Ta) and Li 7+x A x La 3-x Zr2O 12 (0 <x<3, A는 Zn) 중에서 선택된 하나 이상을 포함할 수 있다.

[0075] The above halide-based solid electrolyte may include a Li element, an M element (M is a metal other than Li), and an X element (X is a halogen). As X, for example, F, Cl, Br, and I may be mentioned. In particular, in the halide-based solid electrolyte, at least one of Br and Cl is suitable as X. In addition, as the M, for example, a metal element such as Sc, Y, B, Al, Ga, or In may be mentioned.

[0076] The composition of the above halide-based solid electrolyte is not particularly limited, but Li 6-3a M a Br b Cl c(In the formula, M is a metal other than Li, and 0 <a<2, 0≤b≤6, 0≤c≤6, b+c=6)로 표현될 수 있다. 이때, 상기 a는 0.75 이상일 수 있고, 1 이상일 수 있고, a는, 1.5 이하일 수 있다. 상기 b는 1 이상일 수 있고, 2 이상일 수 있다. 또한, 상기 c는, 3 이상일 수 있고, 4 이상일 수도 있다. 상기 할라이드계 고체 전해질의 구체적인 예로는 Li3YBr6, Li3YCl6또는 Li3YBr2Cl4를 들 수 있다.

[0077] The above solid electrolyte may be in the form of particles. At this time, the average particle diameter (D50) of the solid electrolyte may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.5 ㎛ to 5.0 ㎛, 0.5 ㎛ to 4.0 ㎛, 0.5 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.5 ㎛ to 1.0 ㎛.

[0078] The above solid electrolyte layer may further include a binder. At this time, the binder may be styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, but is not limited thereto, and any binder used in the relevant technical field may be used. The acrylate polymer may be butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0079] The binder content in the solid electrolyte layer can be appropriately controlled and does not need to be limited.

[0080] The above solid electrolyte layer can be manufactured by placing a solid electrolyte in a mold and pressing it, or can be formed by adding a solid electrolyte to a binder solution, coating the same on a base film, and drying it. The solvent of the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The pressing process may be performed by applying a pressure of 10 MPa to 500 MPa, or a pressure of 100 MPa to 400 MPa. Since the solid electrolyte layer forming process is widely known in the art, a detailed description thereof will be omitted herein.

[0081] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0082] The solid electrolyte layer may further include an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0083] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0084] The above lithium salts include, for example, LiSCN, LiN(CN)2, Li(CF3SO2)3C, LiC4F9SO3, LiN(SO2CF2CF3)2, LiCl, LiF, LiBr, LiI, LiB(C2O4)2, LiBF4, LiBF3(C2F5), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, It may include LiN(SO2F)2), LiCF3SO3, LiAsF6, LiSbF6, LiClO4 or mixtures thereof.

[0085] In addition, the lithium salt may be an imide-based one, and for example, the imide-based lithium salt may include lithium bis(trifluoro methanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt may maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with an ionic liquid.

[0086] The above ionic liquid has a melting point below room temperature and is a salt or room-temperature molten salt that is liquid at room temperature and consists only of ions.

[0087] The above ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0088] The ionic liquid may be at least one selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0089] In the above solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0090] Bipolar

[0091] According to one embodiment, a positive electrode of an all-solid-state battery includes a positive electrode current collector and a positive electrode active material layer positioned on one surface of the positive electrode current collector.

[0092] The above-described positive electrode active material layer may include a positive electrode active material. The positive electrode active material may be a positive electrode active material capable of reversibly absorbing and releasing lithium ions. For example, the positive electrode active material may use at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof. A specific example of the positive electrode active material is Li. a A 1-b B 1 b D 1 2(0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b B 1 b O 2-c D 1 c (0.90≤a≤1.8, 0 ≤b≤0.5, 0≤c≤0.5); Li a E 2-b B 1 b O 4-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤05); Li a Ni 1-b-c Co b B1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Co c L 1 d G eO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a MnG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI 1 O2; LiNiVO4; Li (3-f) J2(PO4)3(0≤f≤2); Li (3-f) Fe2(PO4)3(0≤f≤2); or LiFePO4.

[0093] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1 is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0094] According to one implementation example, LiNi is used as the positive electrode active material. x Co y Al z O2(NCA), LiNi x Coy Mn z O2(NCM)(but, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1) 등의 삼성분계 리튬 전이 금속 산화물을 들 수 있다.

[0095] Of course, it is also possible to use a compound having a coating layer on the surface of the compound, or it is also possible to use a mixture of the compound and a compound having a coating layer. The coating layer may include at least one coating element compound selected from the group consisting of an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, and a hydroxycarbonate of the coating element. The compounds forming these coating layers may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer forming process may use any coating method as long as it can coat the compound with these elements in a method that does not adversely affect the properties of the positive electrode active material (for example, spray coating, dipping, etc.), and since this is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0096] In addition, as the above coating layer, any known coating layer for the positive electrode active material of an all-solid-state battery can be applied. For example, it can be a buffer layer that plays a role in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte. For example, the buffer layer can include a lithium-metal-oxide, wherein the metal can be one or more elements selected from the group consisting of Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, and Zr. Specific examples of the buffer layer include Li2O-ZrO2 (LZO), LiNbO2, etc.

[0097] Furthermore, when the cathode active material is a ternary compound containing nickel, cobalt, and manganese, or nickel, cobalt, and aluminum, the capacity density of the all-solid-state battery can be further improved and metal dissolution from the cathode active material can be further reduced in a charged state. Consequently, the all-solid-state battery can exhibit improved long-term reliability and cycle performance in a charged state.

[0098] The average particle size of the positive electrode active material may be 1 μm to 25 μm, for example, 3 μm to 25 μm, 1 μm to 20 μm, 1 μm to 18 μm, 3 μm to 15 μm, or 5 μm to 15 μm. For example, the positive electrode active material may include small particles having an average particle size (D50) of 1 μm to 9 μm and large particles having an average particle size (D50) of 10 μm to 25 μm. A positive electrode active material having such a particle size range can be harmoniously mixed with other components within a positive electrode active material layer and can realize high capacity and high energy density.

[0099] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single crystal. In addition, the above-mentioned positive electrode active material may be in the form of a spherical or nearly spherical shape, or may be polyhedral or irregular.

[0100] In addition, the content of the positive electrode active material in the positive electrode active material layer is not particularly limited, and may be within a range applicable to the positive electrode layer of a conventional all-solid-state secondary battery. For example, with respect to the total 100 wt% of the positive electrode active material layer, the positive electrode active material may be included in an amount of 55 wt% to 99.5 wt%, for example, 65 wt% to 95 wt%, or 75 wt% to 91 wt%.

[0101] The above positive electrode active material layer may further include a binder and / or a conductive material.

[0102] The above binder may include, but is not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0103] The above binder may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on 100 wt% of the total positive electrode active material layer. Within the above content range, the binder can sufficiently exhibit adhesive ability without deteriorating battery performance.

[0104] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotubes; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0105] The conductive material may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on 100 wt% of the total weight of the positive electrode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0106] The above-described positive electrode active material layer may additionally include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte. The solid electrolyte is as described in the above-described solid electrolyte, and may be the same as or different from the solid electrolyte included in the solid electrolyte layer.

[0107] With respect to the total 100 wt% of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%. When the solid electrolyte is included in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0108] The above anode current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet.

[0109] Elastic layer

[0110] An all-solid-state battery according to one embodiment may further include an elastic layer for buffering thickness changes that occur during charging and discharging. The elastic layer may be positioned between the negative electrode and the case.

[0111] The above elastic layer may be a material having an elastic recovery rate of 50% or more and an insulating function, and specifically may be silicone rubber, acrylic rubber, fluorine rubber, nylon, synthetic rubber, or a combination thereof. The above cushioning material may be in the form of a polymer sheet.

[0112] <Method for manufacturing an all-solid-state battery>

[0113] An all-solid-state battery according to an embodiment can be manufactured by the following process.

[0114] A first layer composition is prepared by adding an oxide of a metal capable of alloying with lithium and a first binder to a first solvent. In addition, a second layer composition is prepared by adding a carbon-based material and a second binder to a second solvent.

[0115] The first solvent may be N-methyl pyrrolidone, octyl acetate, isobutyl isobutyrate toluene, xylene, water, or a combination thereof, and the second solvent may be N-methyl pyrrolidone, octyl acetate, isobutyl isobutyrate toluene, xylene, water, or a combination thereof.

[0116] The first layer composition is applied to a first substrate and dried to form a first structure having a first layer formed thereon. The second layer composition is applied to a second substrate and dried to form a second structure having a second layer formed thereon. The second substrate may be stainless steel, but is not limited thereto. The first substrate may be a current collector.

[0117] The above coating process can be performed by spray coating, slurry casting, or sputter coating. Depending on the coating process, the thicknesses of the first and second layers can be controlled, and for example, the thickness ratio of the first and second layers can be set to 1:10 to 1:3.

[0118] The second structure is positioned so that the second layer is in contact with one surface of the solid electrolyte layer, and after the first pressing, the second substrate is removed to transfer the second layer to the solid electrolyte layer. The first pressing process can be performed at 1 MPa to 500 MPa, 10 MPa to 400 MPa, or 100 MPa to 400 MPa.

[0119] Next, the first structure is positioned so that the first layer is in contact with the second layer, and a second compression process is performed to form the first layer on the second layer. The second compression process can be performed at 1 MPa to 500 MPa, 10 MPa to 400 MPa, or 100 MPa to 400 MPa. However, the second compression process can be performed under a lower pressure than the first compression process.

[0120] Through the above process, the second layer, the first layer, and the negative electrode of the current collector can be formed on the solid electrolyte layer.

[0121] Next, a laminate is prepared by positioning the positive electrode on the surface opposite to the surface of the solid electrolyte layer in contact with the second layer. The laminate is pressed to manufacture an all-solid-state battery.

[0122] The pressurizing process can be performed at a temperature ranging from 25°C to 90°C. In addition, the pressurizing process can be performed by pressurizing at a pressure of 550 MPa or less, for example, 500 MPa or less, for example, 1 MPa to 500 MPa. The pressurizing time can vary depending on the temperature and pressure, and can be, for example, less than 30 minutes. The pressurizing process can be, for example, isostatic pressing, roll pressing, plate pressing, or warm isostatic pressing.

[0123] The above-mentioned all-solid-state secondary battery may be a unit cell having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of positive electrode / solid electrolyte layer / negative electrode / solid electrolyte layer / positive electrode, or a laminated battery in which the structure of the unit cell is repeated.

[0124] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0125] Fig. 2 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to Fig. 2, the all-solid-state battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative current collector (401), a first layer (403) and a second layer (405), a solid electrolyte layer (300), and a positive electrode (200) including a positive active material layer (203) and a positive current collector (201) are laminated is housed in a case such as a pouch. The all-solid-state battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400).

[0126] Although FIG. 2 illustrates one electrode assembly including a cathode (400), a solid electrolyte layer (300), and a cathode (200), an all-solid-state battery may be manufactured by stacking two or more electrode assemblies. For example, 2 to 100, 3 to 50, 4 to 20, etc. may be stacked.

[0127] Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0128] (Example 1)

[0129] 90 mg of β-Li3PS4 (NEI) was placed in a mold with an inner diameter of 10 mm and pressed at 200 MPa to produce a solid electrolyte layer with a thickness of 100 μm.

[0130] A first layer composition was prepared by mixing ZnO (average particle size: 500 nm) and polyvinylidene fluoride in a weight ratio of 9:1 in an N-methyl pyrrolidone solvent.

[0131] The first layer composition was applied to stainless steel using a slurry casting method and dried to manufacture a first assembly having a first layer having a thickness of 1 μm.

[0132] A second layer composition was prepared by mixing carbon black (SC65, MTI) and polyvinylidene fluoride in a weight ratio of 9:1 in an N-methyl pyrrolidone solvent.

[0133] The second layer composition was applied to a stainless steel current collector by a slurry casting method and dried to manufacture a second assembly having a second layer having a thickness of 3 μm.

[0134] After positioning the first assembly so that the first layer is in contact with the solid electrolyte layer, pressing at 300 MPa was performed, and the stainless steel was removed to transfer the first layer to the solid electrolyte layer. After positioning the second assembly so that the second layer is in contact with the first layer, pressing at 380 MPa was performed to form the first layer, the second layer, and the negative electrode of the current collector.

[0135] Next, a lithium metal foil (thickness: 400 μm, Honjo) was placed on the surface opposite to one surface of the solid electrolyte layer on which the negative electrode was formed, and then pressurized at 5 MPa to manufacture a half-cell. In the manufactured all-solid-state half-cell, the thickness of the first layer was 1 μm, the thickness of the second layer was 3 μm, and therefore the thickness ratio of the first and second layers was 1:3.

[0136] (Example 2)

[0137] A half-cell was manufactured in the same manner as in Example 1, except that the thickness of the first layer was changed to 3 μm and a negative electrode was formed with a thickness ratio of the first and second layers of 1:1.

[0138] (Example 3)

[0139] A half-cell was manufactured in the same manner as in Example 1 except that SnO(II) was used instead of ZnO.

[0140] (Example 4)

[0141] A half-cell was manufactured in the same manner as in Example 3, except that the thickness of the first layer was changed to 3 μm and a negative electrode was formed with a thickness ratio of the first and second layers of 1:1.

[0142] (Comparative Example 1)

[0143] A carbon layer composition was prepared by mixing carbon black (SC65, MTI) and polyvinylidene fluoride in a weight ratio of 9:1 in an N-methyl pyrrolidone solvent.

[0144] The above carbon layer composition was applied to a stainless steel current collector by a slurry casting method and dried to manufacture an assembly in which a carbon layer having a thickness of 3 μm was formed.

[0145] After positioning the assembly so that the carbon layer was in contact with the solid electrolyte layer of Example 1, the assembly was pressed at 300 MPa to form a carbon layer and a negative electrode of the current collector on the solid electrolyte layer.

[0146] Next, a lithium metal foil (thickness: 400 μm, Honjo) was placed on the surface opposite to one side of the solid electrolyte layer where the cathode was formed, and then pressurized at 5 MPa to manufacture a half-cell. In the manufactured all-solid-state half-cell, the thickness of the carbon layer was 3 μm.

[0147] (Comparative Example 2)

[0148] A ZnO layer composition was prepared by mixing ZnO (average particle size: 500 nm) and polyvinylidene fluoride in a weight ratio of 9:1 in an N-methyl pyrrolidone solvent.

[0149] The above ZnO layer composition was applied to a stainless steel current collector by a slurry casting method and dried to manufacture an assembly having a ZnO layer having a thickness of 1 μm.

[0150] After positioning the assembly so that the ZnO layer was in contact with the solid electrolyte layer of Example 1, the assembly was pressed at 300 MPa to form the ZnO layer and the negative electrode of the current collector on the solid electrolyte layer.

[0151] Next, a lithium metal foil (thickness: 400 μm, Honjo) was placed on the surface opposite to one side of the solid electrolyte layer where the cathode was formed, and then pressurized at 5 MPa to manufacture a half-cell. In the manufactured all-solid-state half-cell, the thickness of the carbon layer was 3 μm.

[0152] (Comparative Example 3)

[0153] A first layer composition was prepared by mixing ZnO (average particle size: 500 nm), carbon black (SC65, MTI), and polyvinylidene fluoride in a weight ratio of 3:9:1 in an N-methyl pyrrolidone solvent.

[0154] The first layer composition was applied to stainless steel using a slurry casting method and dried to manufacture a first assembly having a first layer having a thickness of 4 μm.

[0155] After positioning the first assembly so that the first layer is in contact with the solid electrolyte layer of the above Example 1, the first assembly was pressed at 300 MPa, and the stainless steel was removed to transfer the first layer to the solid electrolyte layer, thereby forming the first layer and the negative electrode of the current collector on the solid electrolyte layer.

[0156] Next, a lithium metal foil (thickness: 400 μm, Honjo) was placed on the surface opposite to one side of the solid electrolyte layer where the cathode was formed, and then pressurized at 5 MPa to manufacture a half-cell. In the manufactured all-solid-state half-cell, the thickness of the first layer was 4 μm.

[0157] Experimental Example 1) SEM Evaluation

[0158] Cross-sectional SEM photographs of the cathode and solid electrolyte layer of Example 1 and Comparative Examples 1 and 2 are shown in FIGS. 3, 4, and 5, respectively. In FIGS. 3 to 5, SE represents the solid electrolyte layer, carbon represents the layer where carbon black is located, and ZnO represents the layer where ZnO is located.

[0159] As shown in Fig. 3, Example 1 confirms that lithium is deposited in a pillar shape between the second layer and the first layer.

[0160] As shown in Fig. 4, in Comparative Example 1, lithium was deposited in a wavy shape on the current collector, and as shown in Fig. 5, in Comparative Example 2, lithium was deposited in a columnar shape, but it was formed at the interface in contact with the solid electrolyte.

[0161] Experimental Example 2) Coulomb Efficiency Evaluation

[0162] The half-cells manufactured in Example 1 and Comparative Examples 1 and 2 were subjected to 90 charge-discharge cycles at 0.25C at 60°C, under the conditions of a current density of 0.5 mA / cm2 and a capacity of 2 mAh / cm2. The ratio of the charge capacity to the discharge capacity at each cycle was obtained. The results are shown in Figure 6 as ◎ long-term efficiency.

[0163] As shown in Fig. 6, Example 1 showed a coulombic efficiency of about 95% even after 90 charge / discharge cycles, whereas Comparative Example 1 and Comparative Example 2 had a short circuit at about 22 and 32 cycles, respectively, and charging / discharging could not be performed thereafter.

[0164]

[0165] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. Current collector; A first layer positioned on the current collector and composed of an oxide of a metal capable of alloying with lithium and a first binder; and A second layer located on the first layer and composed of a carbon-based material and a second binder A cathode for an all-solid-state battery comprising:

2. In paragraph 1, The above-mentioned oxide of a metal capable of being alloyed with lithium is ZnO, SnO2(Ⅳ), SnO(Ⅱ), Bi2O3 or a combination thereof, which is an anode for an all-solid-state battery.

3. In paragraph 1, An all-solid-state negative electrode having a thickness ratio of the first layer and the second layer of 1:1 to 1:

10.

4. In paragraph 1, An all-solid-state negative electrode having a thickness ratio of the first layer and the second layer of 1:1 to 1:

7.

5. In paragraph 1, An all-solid-state battery negative electrode having a thickness of the first layer of 1 ㎛ to 10 ㎛.

6. In paragraph 1, An all-solid-state negative electrode having a thickness of the first layer of 1 ㎛ to 5 ㎛.

7. In paragraph 1, An all-solid-state battery negative electrode having a thickness of the second layer of 1 ㎛ to 10 ㎛.

8. In paragraph 1, An all-solid-state negative electrode having a thickness of the second layer of 2 μm to 7 μm.

9. In paragraph 1, The above carbon-based material is an amorphous carbon negative electrode for an all-solid-state battery.

10. In paragraph 9, The above amorphous carbon is a cathode for an all-solid-state battery, which is carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, graphene or a combination thereof.

11. In paragraph 1, An all-solid-state battery negative electrode, wherein the first binder and the second binder are polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, or a combination thereof.

12. In paragraph 1, An all-solid-state battery negative electrode, wherein the content of the oxide of the metal capable of forming an alloy with the lithium is 80 to 99 wt% with respect to 100 wt% of the entire first layer.

13. In paragraph 1, An all-solid-state negative electrode, wherein the first binder content is 1 wt% to 20 wt% based on 100 wt% of the total of the first layer.

14. In paragraph 1, An all-solid-state battery negative electrode, wherein the content of the carbon-based material is 80 to 99 wt% with respect to 100 wt% of the entire second layer.

15. In paragraph 1, An all-solid-state negative electrode, wherein the second binder content is 1 wt% to 20 wt% based on 100 wt% of the total of the second layer.

16. In paragraph 1, The above current collector is an all-solid-state battery negative electrode made of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof.

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

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