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

Abstract

The present invention relates to a positive electrode for an all-solid-state battery and an all-solid-state battery including same. The positive electrode for an all-solid-state battery includes a binder matrix and a composite active material embedded in the binder matrix. The composite active material includes: a core comprising a positive electrode active material and a conductive material attached on the surface of the positive electrode active material; and an electrolyte layer positioned on the surface of the core.

Description

Cathode for all-solid-state battery and all-solid-state battery containing same

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

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

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

[0004] Accordingly, the development of all-solid-state batteries using lithium metal as the cathode is underway. All-solid-state batteries are composed entirely of solid materials, specifically those using solid electrolytes. Because lithium metal has a large potential difference with the anode, it possesses a high average voltage and a theoretical capacity of approximately 3860 mAh / g, enabling high energy density. Furthermore, the use of a solid electrolyte offers improved safety compared to batteries using liquid electrolytes.

[0005] One embodiment provides a positive electrode for an all-solid-state battery exhibiting excellent electrochemical properties.

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

[0007] One embodiment provides a positive electrode for an all-solid-state battery, comprising: a binder matrix; and a composite active material embedded within the binder matrix, wherein the composite active material comprises a core including a positive electrode active material and a conductive material attached to a surface of the positive electrode active material; and an electrolyte layer positioned on a surface of the core.

[0008] Another embodiment provides an all-solid-state battery comprising the positive electrode; the negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode.

[0009] An all-solid-state battery cathode according to one embodiment can exhibit excellent electrochemical properties by using a small amount of binder.

[0010] Figure 1 is a schematic diagram illustrating a composite active material for an all-solid-state battery according to one embodiment.

[0011] Figure 2 is a schematic drawing showing a part of an all-solid-state battery positive electrode according to one embodiment.

[0012] Figure 3 is a cross-sectional view schematically showing an all-solid-state battery according to one embodiment.

[0013] Figure 4 is a cross-sectional view schematically showing an all-solid-state battery according to another embodiment.

[0014] 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.

[0015] 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.

[0016] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0017] It should be understood that terms such as "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0018] 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.

[0019] 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.

[0020] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0021] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there are other parts in between.

[0022] 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.

[0023] "Thickness" may be measured, for example, from photographs taken with an optical microscope such as a scanning electron microscope.

[0024] One embodiment provides a positive electrode for an all-solid-state battery, comprising a binder matrix and a composite active material embedded within the binder matrix. The positive electrode according to one embodiment includes a positive electrode active material layer formed of the composite active material, and a positive electrode current collector supporting the positive electrode active material layer.

[0025] The composite active material may include a core including a positive electrode active material and a conductive material attached to the surface of the positive electrode active material; and an electrolyte layer positioned on the surface of the core. The electrolyte layer may be positioned to substantially completely surround the surface of the core, or may be positioned to cover a portion of the surface of the core.

[0026] Fig. 1 schematically illustrates a composite active material (1), which includes a positive electrode active material (3), a core including a conductive material (5) attached to the surface of the positive electrode active material (3), and an electrolyte layer (7) positioned on the surface of the core. Fig. 1 illustrates a form in which the conductive material (5) is not covered by the electrolyte layer (7), but is not limited thereto, and the conductive material may be completely covered by the electrolyte layer.

[0027] FIG. 2 schematically illustrates a portion of a positive electrode (10) including the composite active material shown in FIG. 1, wherein the composite active material is embedded in a binder matrix (9).

[0028] In one embodiment, the binder matrix may be formed of a fibrous binder that does not react with a solid electrolyte, for example, a sulfide-based solid electrolyte. For example, the fibrous binder may be a fiberized polymer binder, such as polytetrafluoroethylene, polyvinyl alcohol, polyvinylidene fluoride, or a combination thereof. The fibrous binder may be a nanofiber.

[0029] Since these fibrous binders have adhesive properties themselves, there is no need to add the fibrous binder to a solvent to liquefy it.

[0030] In one embodiment, the content of the binder matrix may be 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, or 0.1 wt% to 2 wt% based on the total weight of the positive electrode. When the content of the binder matrix is ​​within the above range, lithium ion conduction channels and electron conduction channels can be sufficiently formed.

[0031] In one embodiment, the positive electrode active material is included as a composite active material, and the composite active material may be present in a form embedded within the binder matrix. For example, the composite active material may be attached to a fibrous binder constituting the binder matrix and present in a form embedded within the matrix.

[0032] The above composite active material includes a core and a solid electrolyte layer surrounding the surface of the core, and the core may include a positive electrode active material and a conductive material attached to the surface of the positive electrode active material.

[0033] The content of the conductive material may be 0.1 wt% to 10 wt%, 0.1 wt% to 5 wt%, or 0.1 wt% to 1 wt% based on the total weight of the anode.

[0034] Additionally, the content of the electrolyte may be 3 wt% to 20 wt%, 3 wt% to 15 wt%, or 7 wt% to 14 wt% with respect to the total weight of the positive electrode.

[0035] In one embodiment, the content of the conductive material is preferably within the above range, but less than the content of the electrolyte. When the conductive material is within the above range, particularly when included in the anode at a lower content than the electrolyte, the content of the conductive material with a large surface area is low, thereby reducing the binder content, thereby improving electrochemical properties and increasing the composite density.

[0036] In one embodiment, the conductive material is used to provide conductivity to the electrode, and any material that does not cause a chemical change and is electronically conductive can be used in the battery to be constructed. The conductive material may be a carbon-based material, a metal-based material, a conductive polymer, or a combination thereof. Specific examples of the conductive material include carbon-based materials such as carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, graphene, 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 a combination thereof.

[0037] The above electrolyte may be a solid electrolyte, and may be, for example, 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.

[0038] 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 Ae (a, b, c, d and e are each integers greater than or equal to 0 and less than or equal to 12, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I). The sulfide-based solid electrolyte may be, for example, Li 7-x PS 6-x F x (0≤x≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) or Li 7-x PS 6-x I x (0≤x≤2) can be. Also, specifically, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0039] In one embodiment, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The argyrodite-type sulfide-based solid electrolyte may be, for example, Li a M b P c S d A e (a, b, c, d and e are all 0 or more and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I), and specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li6PS5I, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0040] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixture thereof. For example, the sulfide-based solid electrolyte may be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3. Mechanical milling or a solution method can be applied as a mixing method. Mechanical milling is a method in which starting materials are placed in a reactor and vigorously stirred with a ball mill, etc. to pulverize the starting materials and mix them. When the solution method is used, the starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. In addition, additional calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte can become more solid.

[0041] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0042] The above oxide-based solid electrolyte is, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), Pb(Mg3Nb 2 / 3)O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr, x is an integer from 1 to 10), or a mixture thereof.

[0043] The above solid polymer electrolytes include, for example, polyethylene oxide, poly(diallyldimethylammonium)trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, Li3PO4·Li2S·SiS2, Li2S·GeS2·Ga2S3, Li2O·11Al2O3, Na2O·11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3(0.1≤x≤0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x (M,Al,Ga) x (Ge 1-y Ti y ) 2-x (PO4)3(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..

[0044] 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.

[0045] The composition of the above halide-based solid electrolyte is not particularly limited, but Li6-3a M a Br b Cl c (In the formula, M is a metal other than Li, and 0 <a<2, 0≤b≤6, 0≤c≤6, b+c=6)로 표현될 수 있다. 이때, 상기 a는 0.75 이상일 수 있고, 1 이상일 수 있고, a는, 1.5 이하일 수 있다. 상기 b는 1 이상일 수 있고, 2 이상일 수 있다. 또한, 상기 c는, 3 이상일 수 있고, 4 이상일 수도 있다. 상기 할라이드계 고체 전해질의 구체적인 예로는 Li3YBr6, Li3YCl6또는 Li3YBr2Cl4를 들 수 있다.

[0046] The above solid electrolyte is in the form of particles, and the average particle diameter (D50) may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.5 ㎛ to 5.0 ㎛, 0.5 ㎛ to 4.0 ㎛, 0.5 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.5 ㎛ to 1.0 ㎛.

[0047] In one embodiment, the positive electrode active material may be a positive electrode active material capable of reversibly absorbing and releasing lithium ions. For example, the positive electrode active material may use at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof. Specific examples of the positive electrode active material include Li a A 1-b B 1 b D 1 2(0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b B 1 b O 2-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a E 2-b B 1 b O 4-c D 1 c(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤05); Li a Ni 1-b-c Co b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Co b B 1 c O 2-α 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); Lia Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); 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.

[0048] 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, and 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.

[0049] According to one implementation example, LiNi is used as the positive electrode active material. x Co y Al z O2(NCA), LiNi x Co y Mn z O2(NCM)(but, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1) 등의 삼성분계 리튬 전이 금속 산화물을 들 수 있다.

[0050] 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.

[0051] In addition, as the above coating layer, any known coating layer of the positive electrode active material of an all-solid-state battery can be applied, and examples thereof include Li2O-ZrO2 (LZO).

[0052] 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.

[0053] Here, examples of the shape of the positive electrode active material include particle shapes such as spherical or oval. In addition, the average particle diameter of the positive electrode active material is not particularly limited and may be within the range applicable to positive electrode active materials of existing all-solid-state secondary batteries.

[0054] In one embodiment, furthermore, the content of the positive electrode active material may be 75 wt% to 94 wt%, or 87 wt% to 92 wt%, based on 100 wt% of the total positive electrode.

[0055] According to one embodiment, the positive electrode for an all-solid-state battery may be a sheet-shaped positive electrode. A sheet-shaped positive electrode refers to a positive electrode in which a positive electrode active material layer is formed in a sheet shape.

[0056] The positive electrode current collector supporting the positive electrode active material layer 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.

[0057] In one embodiment, the thickness of the positive electrode active material layer may be 70 μm to 500 μm, or may be 150 μm to 300 μm. When the thickness of the positive electrode active material layer is within the above range, the electrode is flexible, and cracks and short circuits due to impact are further suppressed, thereby exhibiting improved safety.

[0058] The manufacturing process for such an all-solid-state battery positive electrode is described below. The mixing ratios in the manufacturing process below are based on the weight ratio in the final positive electrode. For example, the content ratios of each component in a 100 wt% positive electrode are described.

[0059] A mixture is prepared by mixing a positive electrode active material and a first conductive material.

[0060] The mixing ratio of the positive electrode active material and the first conductive material may be a weight ratio of 85:0.5 to 94:5, or a weight ratio of 85:0.1 to 94:0.2. When the mixing ratio of the positive electrode active material and the conductive material is within the above range, the conductive material can more appropriately cover the active material, thereby maintaining a good conduction path.

[0061] The mixing process of the positive electrode active material and the first conductive material may be performed at a stirring speed of 1000 rpm to 5000 rpm, or 1000 rpm to 3000 rpm. The mixing process may be performed for 1 minute to 10 minutes, or 3 minutes to 7 minutes.

[0062] When the above mixing process is performed at the above mixing speed for the above time, the conductive material can be well mixed with the positive electrode active material without a chopping phenomenon, so that the conductive material's conduction path is well maintained, and the effect of improving the high-rate characteristics can be obtained.

[0063] An electrolyte mixture is prepared by mixing the above mixture and the first solid electrolyte.

[0064] The amount of the first solid electrolyte used may be 0.1 wt% to 2 wt%, or 0.5 wt% to 1 wt%, based on 100 wt% of the total electrolyte mixture. When the amount of the solid electrolyte used is within the above range, the electrolyte can be uniformly distributed and the density can be increased.

[0065] The mixing process of the above mixture and the first solid electrolyte can be performed at a mixing speed of 1000 rpm to 10,000 rpm, or 1000 rpm to 3000 rpm. The mixing process can be performed for 1 minute to 10 minutes, or 1 minute to 7 minutes.

[0066] The obtained electrolyte mixture, the second conductive agent, the second solid electrolyte, and the binder are mixed to prepare a binder mixture. The mixing process can be performed at a mixing speed of 1,000 rpm to 10,000 rpm, 1,000 rpm to 3,000 rpm, or 1,000 rpm to 2,200 rpm. The mixing process can be performed once to 15 times for 1 to 10 minutes, or once to 7 minutes each time, or once to 10 times.

[0067] The first conductive material and the second conductive material are as described above and may be the same or different from each other. In addition, the first solid electrolyte and the second solid electrolyte are as described above and may be the same or different from each other.

[0068] The amount of the binder used may be 0.1 wt% to 5 wt%, or 0.1 wt% to 1 wt%, based on 100 wt% of the total binder mixture. When the amount of the binder used is within the above range, a coating layer can be manufactured with a small amount of binder.

[0069] The above binder mixture is extruded to manufacture a positive electrode active material layer.

[0070] The above extrusion process can be performed using an extruder at a temperature of 50°C to 100°C, a screw rotation speed of 50 rpm to 200 rpm, and a torque of 1 to 5 during extrusion. The torque can be adjusted by the amount of the binder mixture fed into the extruder, and can be fed, for example, at 500 g / hour to 2000 g / hour. For example, torques 1 to 2 correspond to input amounts of 500 g / hour to 900 g / hour, torques 3 to 4 correspond to input amounts exceeding 900 g / hour and not exceeding 1200 g / hour, and torque 5 corresponds to input amounts exceeding 1200 g / hour and not exceeding 1400 g / hour.

[0071] When the extrusion process is performed under the above conditions, the desired positive electrode active material layer, particularly the sheet-shaped positive electrode active material layer, can be appropriately manufactured.

[0072] After performing the above extrusion process, a deagglomeration process may be further performed on the extruded product. The deagglomeration process may be performed at a rotation speed of 5,000 rpm to 20,000 rpm or 7,000 rpm to 15,000 rpm for 1 to 10 minutes or 1 to 5 minutes.

[0073] Additionally, a pressing process may be further performed on the product subjected to the extrusion process or the crushed product. The pressing process may be performed using a roll-press process. This process may be performed at a temperature of 20°C to 100°C, or 30°C to 80°C. Additionally, the roll rotation speed may be 1 rpm to 10 rpm, or 2 rpm to 5 rpm.

[0074] A positive electrode can be manufactured by positioning a current collector on the manufactured positive electrode active material layer. The process of positioning the current collector can be performed by positioning the current collector on the positive electrode active material layer before battery manufacturing, or by positioning the positive electrode active material layer in contact with the solid electrolyte layer during the battery manufacturing process, and then positioning the current collector on the other side of the positive electrode active material layer that is not in contact with the solid electrolyte layer.

[0075] Another embodiment provides an all-solid-state battery comprising the positive electrode. The all-solid-state battery comprises a negative electrode and a solid electrolyte layer positioned between the positive electrode and the negative electrode.

[0076] The above cathode includes a current collector and a cathode layer positioned on one surface of the current collector.

[0077] The above negative electrode layer may be a negative electrode active material layer or a negative electrode coating layer. Alternatively, the above negative electrode layer may be a lithium metal layer.

[0078] The above negative electrode active material layer includes a negative electrode active material and may further include a binder, a conductive material, and / or a solid electrolyte.

[0079] The above negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0080] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0081] As the above lithium metal alloy, an alloy of lithium and one or more metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0082] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x (0 <x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 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, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택되는 것을 사용할 수 있다.

[0083] The silicon-carbon composite may be, for example, a silicon-carbon composite including a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. As the amorphous carbon precursor, coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin such as a phenol resin, a furan resin, or a polyimide resin may be used. At this time, the content of silicon may be 10 wt% to 50 wt% with respect to the total weight of the silicon-carbon composite. In addition, the content of the crystalline carbon may be 10 wt% to 70 wt% with respect to the total weight of the silicon-carbon composite, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to the total weight of the silicon-carbon composite. In addition, the thickness of the amorphous carbon coating layer may be 5 nm to 100 nm.

[0084] The average particle diameter (D50) of the above silicon particles may be 10 nm to 20 μm, for example, 10 nm to 500 nm. The silicon particles may exist in an oxidized form, and at this time, the atomic content ratio of Si:O in the silicon particles, which indicates the degree of oxidation, may be 99:1 to 33:67. The silicon particles may be SiO x It can be a particle, in which case SiO x In the range of x, it can be greater than 0 and less than 2. Here, the average particle diameter (D50) is measured by a particle size analyzer using laser diffraction and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution.

[0085] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. The mixing ratio of the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material can be 1:99 to 90:10 by weight.

[0086] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0087] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0088] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may include a non-aqueous binder, an aqueous binder, or a combination thereof.

[0089] The non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof.

[0090] The above-mentioned aqueous binder may be a rubber-based binder or a polymer resin binder. The rubber-based binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The above-mentioned polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0091] When using an aqueous binder as the negative electrode binder, a thickener capable of imparting viscosity may be used together, and the thickener may include, for example, a cellulose-based compound. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. Na, K, or Li may be used as the alkali metal. The amount of the thickener used may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material. The cellulose-based compound may also function as a binder.

[0092] The above binders are not limited to these, and any binder used in the relevant technical field may be used, and their content can also be appropriately adjusted.

[0093] The conductive material is used to provide conductivity to the electrode, and may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, and carbon nanotubes; metal-based materials in the form of metal powder or metal fibers, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0094] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0095] When the above-mentioned negative electrode layer is a negative electrode coating layer, it means that the negative electrode is a precipitation-type negative electrode. The above-mentioned precipitation-type negative electrode means a negative electrode that does not include a negative electrode active material when the battery is assembled, but is precipitated with lithium metal or the like when the battery is charged, and this acts as a negative electrode active material. In more detail, the positive electrode coating layer means a layer that helps lithium ions released from the positive electrode active material during charge / discharge of an all-solid-state battery move toward the negative electrode and be precipitated on the surface of the current collector. That is, a lithium precipitation layer is formed due to the precipitation of lithium ions between the current collector and the negative electrode coating layer, and the lithium precipitation layer acts as a negative electrode active material. Such a negative electrode is generally called a precipitation-type negative electrode. The metal and amorphous carbon included in the negative electrode coating layer do not act as a negative electrode active material that directly participates in the charge / discharge reaction.

[0096] The cathode coating layer may include a metal, a carbon-based material, or a combination thereof that acts as a catalyst. For example, the cathode coating layer may include a metal supported on a carbon-based material, or a mixture of a metal and a carbon-based material. In one embodiment, the cathode coating layer may include a metal and a carbon-based material.

[0097] The carbonaceous material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof, or may be amorphous carbon. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, graphene, or a combination thereof. An example of the carbon black is Super P (Timcal). The amorphous carbon is not limited thereto, and any material classified as amorphous carbon in the relevant field may be used.

[0098] The carbonaceous material may be amorphous carbon, crystalline carbon, or a mixture thereof. The amorphous carbon may be, for example, carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, or a combination thereof. An example of the carbon black may be Super P (Timcal). The crystalline carbon may be natural graphite, artificial graphite, carbon nanotubes, graphene, or a combination thereof. The crystalline carbon may be in the form of amorphous, plate-like, flake-like, spherical, or fiber-like particles.

[0099] In one embodiment, the carbonaceous material may be a single particle, or may be an assembly having a secondary particle form in which primary particles are assembled. When the carbonaceous material is a single particle, the size of the carbonaceous material may be a nano-size with an average particle diameter of 100 nm or less, for example, 10 nm to 100 nm.

[0100] Additionally, when the carbon-based material is an assembly, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0101] In one embodiment, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and may be 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0102] In one embodiment, the particle size of the secondary particles may be 1 µm or more, 3 µm or more, 5 µm or more, 7 µm or more, 10 µm or more, or 15 µm or more, and may be 20 µm or less, 15 µm or less, 10 µm or less, 7 µm or less, 5 µm or less, or 3 µm or less.

[0103] 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.

[0104] The above metal may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd or a combination thereof. As the cathode coating layer includes the above metal, the electrical conductivity of the cathode can be further improved.

[0105] The metal may be a nanoparticle, and the size of the metal nanoparticle may be, for example, an average size of 5 nm to 80 nm, but a nanometer size may be suitably used. By using the metal nanoparticle having such a nano size, the battery characteristics (e.g., life characteristics) of the all-solid-state battery can be improved. If the metal particle size increases to the micrometer level, the uniformity of the metal particles in the negative electrode coating layer decreases, so that the current density in a specific region increases and the cycle life characteristics may deteriorate, which is not suitable.

[0106] Additionally, the content of the metal may be 3 wt% to 30 wt%, 4 wt% to 25 wt%, 5 wt% to 20 wt%, or 5 wt% to 15 wt% with respect to 100 wt% of the entire cathode coating layer.

[0107] Additionally, the carbon-based material may be present in an amount of 70 wt% to 97 wt%, 75 wt% to 96 wt%, 80 wt% to 95 wt%, or 85 wt% to 95 wt% relative to 100 wt% of the total weight of the cathode coating layer.

[0108] The above cathode coating layer may further include a binder. The binder may be an insoluble binder.

[0109] The above-described non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or a combination thereof.

[0110] The binder may be present in an amount of 1 to 15 wt% relative to 100 wt% of the total weight of the cathode coating layer, for example, the binder may be present in an amount of 1 wt% or more, 2 wt% or more, 3 wt% or more, 4 wt% or more, 5 wt% or more, 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, 10 wt% or more, 11 wt% or more, 12 wt% or more, 13 wt% or more, or 14 wt% or more, and 15 wt% or less, 14 wt% or less, 13 wt% or less, 12 wt% or less, 11 wt% or less, 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, or 2 wt% or less relative to 100 wt% of the total weight of the cathode coating layer.

[0111] When the above binder is included in the negative electrode coating layer of the all-solid-state battery in the above content range, the electrical resistance and adhesive strength can be improved, thereby improving the characteristics (battery capacity and output characteristics) of the all-solid-state battery.

[0112] The above-described cathode coating layer may further include additives such as fillers and dispersants. In addition, known materials generally used in all-solid-state batteries may be used as fillers, dispersants, etc. that can be included in the cathode coating layer.

[0113] The thickness of the cathode coating layer may be 1 µm to 20 µm. For example, the thickness of the cathode coating layer may be 1 µm or more, 3 µm or more, 5 µm or more, 20 µm or less, 18 µm or less, 16 µm or less, 14 µm or less, 12 µm or less, or 10 µm or less.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] In one embodiment, since the lithium-containing layer is positioned between the current collector and the negative electrode coating layer, the negative electrode coating layer can serve as a protective layer for the lithium-containing layer, thereby inhibiting the precipitation and growth of lithium dendrites. This can suppress short-circuiting and capacity degradation of the all-solid-state battery, and consequently improve the cycle life of the all-solid-state battery.

[0121] The above solid electrolyte layer includes a solid electrolyte. The solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte. Examples of the sulfide-based solid electrolyte, the oxide-based solid electrolyte, the halide-based solid electrolyte, and the solid polymer electrolyte are as described above. In addition, the solid electrolyte may be the same as or different from the electrolyte used in the positive electrode.

[0122] 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.

[0123] The above solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the same on a base film, and drying the same. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. Since the solid electrolyte layer formation process is widely known in the art, a detailed description thereof will be omitted herein.

[0124] In one embodiment, the all-solid-state battery may further include a buffer material to cushion changes in thickness that occur during charging and discharging. The buffer material may be positioned between the negative electrode and the case, and in the case of a battery in which one or more electrode assemblies are stacked, the buffer material may be positioned between different electrode assemblies.

[0125] The above-mentioned cushioning material may be a material having an elastic recovery rate of 50% or more and an insulating function, and specifically, may be silicone rubber, acrylic rubber, fluorine rubber, nylon, synthetic rubber, or a combination thereof. The above-mentioned cushioning material may be in the form of a polymer sheet.

[0126] 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 electrode collector (401) and a negative electrode layer (403), a solid electrolyte layer (300), and a positive electrode (200) 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). Although Fig. 2 illustrates one electrode assembly including the negative electrode (400), the solid electrolyte layer (300), and the positive electrode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0127] Fig. 3 schematically illustrates an all-solid-state battery according to another embodiment. The all-solid-state battery (100) illustrated in Fig. 3 includes a cathode (200), a cathode current collector (401'), a cathode layer (403') including a cathode (400'), and a solid electrolyte (300) positioned between the cathode (200) and the cathode (400), and includes a battery case (500) in which these are accommodated, and further includes a lithium precipitation layer (405') between the cathode current collector (401') and the cathode coating layer (403'). When the all-solid-state battery is charged, the lithium precipitation layer can be formed by lithium ions being released from the cathode active material and deposited on the cathode current collector (401').

[0128] An all-solid-state battery according to one embodiment can be manufactured by a step of preparing a laminate by positioning a cathode, an anode, and a solid electrolyte layer between the cathode and the anode, and pressing the laminate.

[0129] 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 60 minutes. The pressurizing process can be, for example, isostatic pressing, roll pressing, plate pressing, or warm isostatic pressing.

[0130] 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.

[0131] In the following examples and comparative examples, the mixing ratio is described as the weight ratio in the final positive electrode.

[0132] (Example 1)

[0133] (1) Manufacturing of anode

[0134] LiNi 0.9 Mn 0.05 Co 0.05 A mixture was prepared by mixing the O2 cathode active material and Ketjen Black conductive material in a weight ratio of 85:0.1 using a mixer (Nobailta MINI (manufactured by Hosokawa Micron)) at a stirring speed of 2000 rpm for 2 minutes.

[0135] An electrolyte mixture was prepared by mixing the above mixture and the argyrodite-type solid electrolyte Li6PS5Cl in a weight ratio of 85.1:0.05 using a mixer (Nobailta MINI) at a stirring speed of 2000 rpm for 5 minutes.

[0136] The above electrolyte mixture, Ketjen Black conductive material, argyrodite-type solid electrolyte Li6PS5C, and polytetrafluoroethylene binder were mixed in a weight ratio of 85.15:0.3:13.1:1.45 using a mixer (THINKY MIXER) at a stirring speed of 2000 rpm for 1 minute, 10 times, to prepare a binder mixture.

[0137] The above binder mixture was extruded using an extruder at 60°C, under screw rotation speed of 100 rpm and torque conditions of 2 during extrusion (binder mixture was fed at 500 g / hour) to produce an extrusion product.

[0138] The above extruded product was crushed at a rotation speed of 10,000 rpm for 2 minutes.

[0139] Next, the obtained product was roll-pressed using two rolls at 60°C and a roll rotation speed of 3 rpm to manufacture a sheet-shaped positive electrode active material layer. The thickness of the manufactured sheet-shaped positive electrode active material layer was 200 μm. The manufactured positive electrode active material layer was in a state in which a composite active material of a positive electrode active material, a core of a conductive material attached to the surface of the positive electrode active material, and an electrolyte surrounding the surface of the core were embedded within a binder matrix.

[0140] The positive electrode was manufactured by positioning the positive electrode active material layer on an aluminum positive electrode current collector.

[0141] (2) Manufacturing of cathode

[0142] A cathode coating layer slurry was prepared by mixing Ag nanoparticles (D50: 60 nm) and carbon black in a weight ratio of 10:90 in a water solvent. The carbon black was a mixture of single particles with a particle diameter of 38 nm and secondary particles, and the secondary particles were assembled from primary particles with a particle diameter of 76 nm and secondary particles with a particle diameter of 275 nm.

[0143] After coating the above slurry on a stainless steel foil current collector, vacuum drying was performed at 80°C to manufacture a negative electrode including a 12 μm thick negative electrode coating layer and a 10 μm thick current collector. The thickness of the negative electrode coating layer was 12 μm.

[0144] (3) Manufacturing of solid electrolyte layer

[0145] An isobutyl isobutylate binder solution (solid content: 50 wt%) containing butyl acrylate, an acrylate polymer, was added to an argyrodite-type solid electrolyte Li6PS5Cl and mixed. At this time, the mixing ratio of the solid electrolyte and the binder was set to a weight ratio of 98.7:1.3.

[0146] The above mixing process was performed using a sinky mixer. 2 mm zirconia balls were added to the resulting mixture and stirred again using the sinky mixer to produce a slurry. The slurry was cast onto a polytetrafluoroethylene film and dried at room temperature to produce a solid electrolyte with a solid electrolyte layer thickness of 100 μm.

[0147] (4) Manufacturing of all-solid-state batteries (full cells)

[0148] The positive electrode, the solid electrolyte, and the negative electrode were sequentially laminated, sealed in a pouch shape, and subjected to hydrostatic pressing at a high temperature of 80°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery (mini-cell).

[0149] (Example 2)

[0150] A positive electrode was manufactured in the same manner as in Example 1, except that the mixing ratio of the above mixture and the argyrodite-type solid electrolyte Li6PS5Cl was changed to a weight ratio of 85.1:0.1, and the weight ratio of the electrolyte mixture, Ketjen Black conductive material, argyrodite-type solid electrolyte Li6PS5C, and polytetrafluoroethylene binder was changed to a weight ratio of 85.2:0.3:13.1:1.4.

[0151] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0152] (Example 3)

[0153] A positive electrode was manufactured in the same manner as in Example 1, except that the mixing ratio of the above mixture and the argyrodite-type solid electrolyte Li6PS5Cl was changed to a weight ratio of 85.1:0.2, and the weight ratio of the electrolyte mixture, Ketjen Black conductive material, argyrodite-type solid electrolyte Li6PS5C, and polytetrafluoroethylene binder was changed to 85.3:0.3:13.1:1.3.

[0154] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0155] (Example 4)

[0156] A positive electrode was manufactured in the same manner as in Example 1, except that the mixing ratio of the above mixture and the argyrodite-type solid electrolyte Li6PS5Cl was changed to a weight ratio of 85.1:0.4, and the weight ratio of the electrolyte mixture, Ketjen Black conductive material, argyrodite-type solid electrolyte Li6PS5C, and polytetrafluoroethylene binder was changed to 85.5:0.3:13.1:1.3.

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

[0158] (Example 5)

[0159] LiNi 0.9 Mn 0.05 Co 0.05 An O2 positive electrode active material and Ketjen Black conductive agent were mixed in a weight ratio of 85.2:0.1 to prepare a mixture, and the mixture and the argyrodite-type solid electrolyte Li6PS5Cl were mixed in a weight ratio of 85.3:0.05 to prepare an electrolyte mixture, and the electrolyte mixture, Ketjen Black conductive agent, the argyrodite-type solid electrolyte Li6PS5Cl, and the polytetrafluoroethylene binder were mixed in a weight ratio of 85.35:0.3:13.55:0.8 to prepare a positive electrode in the same manner as in Example 1.

[0160] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0161] (Example 6)

[0162] LiNi 0.9 Mn 0.05 Co 0.05An O2 positive electrode active material and Ketjen Black conductive agent were mixed in a weight ratio of 85.4:0.1 to prepare a mixture, and the mixture and the argyrodite-type solid electrolyte Li6PS5Cl were mixed in a weight ratio of 85.5:0.05 to prepare an electrolyte mixture, and the electrolyte mixture, Ketjen Black conductive agent, the argyrodite-type solid electrolyte Li6PS5Cl, and a polytetrafluoroethylene binder were mixed in a weight ratio of 85.55:0.3:13.55:0.6 to prepare a positive electrode in the same manner as in Example 1.

[0163] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0164] (Example 7)

[0165] LiNi 0.9 Mn 0.05 Co 0.05 An O2 positive electrode active material and Ketjen Black conductive agent were mixed in a weight ratio of 85.6:0.1 to prepare a mixture, and the mixture and the argyrodite-type solid electrolyte Li6PS5Cl were mixed in a weight ratio of 85.7:0.05 to prepare an electrolyte mixture, and the electrolyte mixture, Ketjen Black conductive agent, the argyrodite-type solid electrolyte Li6PS5Cl, and the polytetrafluoroethylene binder were mixed in a weight ratio of 86.75:0.3:13.55:0.4 to prepare a positive electrode in the same manner as in Example 1.

[0166] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0167] (Comparative Example 1)

[0168] (1) Manufacturing of anode

[0169] LiNi 0.9 Mn 0.05 Co 0.05O2 positive electrode active material and Ketjen Black conductive material were mixed in a weight ratio of 85:0.4 using a mixer (Nobailta MINI (manufacturer: Hosokawa Micron)) at a stirring speed of 2000 rpm for 7 minutes.

[0170] The above mixture, azirodite-type solid electrolyte Li6PS5Cl, and polytetrafluoroethylene binder were mixed in a weight ratio of 85.4:13.6:1 using a mixer (THINKY MIXER) at a stirring speed of 2000 rpm for 1 minute each, 10 times to prepare a binder mixture.

[0171] The above binder mixture was extruded using an extruder at 60°C, under screw rotation speed of 100 rpm and torque conditions of 2 during extrusion (binder mixture was fed at 500 g / hour) to produce an extrusion product.

[0172] The above extruded product was crushed at a rotation speed of 10,000 rpm for 2 minutes.

[0173] Next, the obtained product was roll-pressed using two rolls at a roll rotation speed of 3 rpm at 60°C to produce a sheet-shaped positive electrode active material layer. The thickness of the manufactured sheet-shaped positive electrode active material layer was 200 μm. The manufactured positive electrode active material layer was a composite active material of a positive electrode active material and a conductive material attached to the surface of the positive electrode active material, which was embedded within a binder matrix.

[0174] The positive electrode was manufactured by positioning the positive electrode active material layer on an aluminum positive electrode current collector.

[0175] (2) Manufacturing of all-solid-state batteries (full cells)

[0176] The positive electrode, the solid electrolyte of Example 1, and the negative electrode of Example 1 were sequentially laminated, sealed in a pouch shape, and subjected to hydrostatic pressing at a high temperature of 80°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery (minicell).

[0177] (Comparative Example 2)

[0178] (1) Manufacturing of anode

[0179] LiNi 0.9 Mn 0.05 Co 0.05 O2 positive electrode active material and argyrodite type solid electrolyte Li6PS5Cl were mixed with the conductive material in a weight ratio of 85:13.6 using a mixer (Nobailta MINI (manufacturer: Hosokawa Micron)) at a stirring speed of 2000 rpm for 7 minutes.

[0180] The above solid electrolyte mixture, Ketjen Black conductive agent, and polytetrafluoroethylene binder were mixed in a weight ratio of 98.6:0.4:1 using a mixer (THINKY MIXER) at a stirring speed of 2000 rpm for 10 times for 1 minute to prepare a binder mixture.

[0181] The obtained mixture was extruded using an extruder at 60°C under screw rotation speed of 100 rpm and torque of 2 during extrusion to produce an extruded product.

[0182] The above extruded product was crushed at a rotation speed of 10,000 rpm for 2 minutes.

[0183] Next, the obtained product was roll-pressed using two rolls at a roll rotation speed of 3 rpm at 60°C to produce a sheet-shaped positive electrode active material layer. The thickness of the manufactured sheet-shaped positive electrode active material layer was 200 μm. The manufactured positive electrode active material layer was a composite active material comprising a positive electrode active material and a solid electrolyte layer surrounding the surface of the positive electrode active material, which were embedded within a binder matrix.

[0184] The positive electrode was manufactured by positioning the positive electrode active material layer on an aluminum positive electrode current collector.

[0185] (2) Manufacturing of all-solid-state full cells

[0186] The positive electrode, the solid electrolyte of Example 1, and the negative electrode of Example 1 were sequentially laminated, sealed in a pouch shape, and subjected to hydrostatic pressing at a high temperature of 80°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery (minicell).

[0187] (Comparative Example 3)

[0188] (1) Manufacturing of anode

[0189] LiNi 0.9 Mn 0.05 Co 0.05 O2 positive electrode active material and argyrodite type solid electrolyte Li6PS5Cl were mixed with the conductive material in a weight ratio of 85:0.6 using a mixer (Nobailta MINI (manufacturer: Hosokawa Micron)) at a stirring speed of 2000 rpm for 7 minutes.

[0190] The above solid electrolyte mixture, Ketjen Black conductive material, argyrodite-type solid electrolyte Li6PS5Cl and polytetrafluoroethylene binder were added in a weight ratio of 85.6:0.4:13:1 in a xylene solvent and mixed 10 times for 1 minute at a stirring speed of 2000 rpm using a mixer (THINKY MIXER) to prepare a binder mixture.

[0191] The above binder mixture was extruded using an extruder at 60°C, with a screw rotation speed of 100 rpm and a torque of 2 during extrusion, to produce an extrusion product.

[0192] The above extruded product was crushed at a rotation speed of 10,000 rpm for 2 minutes.

[0193] Next, the obtained product was roll-pressed using two rolls at 60°C and a roll rotation speed of 3 rpm to manufacture a sheet-shaped positive electrode active material layer. The thickness of the manufactured sheet-shaped positive electrode active material layer was 130 μm. The manufactured positive electrode active material layer was in a state in which a composite active material of a positive electrode active material, an electrolyte core surrounding the surface of the positive electrode active material, and a conductive material positioned on the surface of the core were embedded in a binder matrix. The positive electrode active material layer was positioned on an aluminum positive electrode current collector to manufacture a positive electrode.

[0194] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0195] (Comparative Example 4)

[0196] (1) Manufacturing of anode

[0197] LiNi 0.9 Mn 0.05 Co 0.05 An electrolyte mixture was prepared by mixing the O2 cathode active material and the argyrodite-type solid electrolyte Li6PS5Cl in a weight ratio of 85:13.6 using a mixer (Nobailta MINI (manufactured by Hosokawa Micron)) at a stirring speed of 2000 rpm for 2 minutes.

[0198] The above electrolyte mixture and Ketjen Black conductive material were mixed in a weight ratio of 98.6:0.4 using a mixer (Nobailta MINI) at a stirring speed of 2000 rpm for 5 minutes to prepare a mixture.

[0199] The above mixture and polytetrafluoroethylene binder were mixed at a ratio of 99:1 using a mixer (THINKY MIXER) at a stirring speed of 2000 rpm for 10 times for 1 minute to prepare a binder mixture.

[0200] The above binder mixture was extruded using an extruder at 60°C, with a screw rotation speed of 100 rpm and a torque of 2 during extrusion, to produce an extrusion product.

[0201] The above extruded product was crushed at a rotation speed of 10,000 rpm for 2 minutes.

[0202] Next, the obtained product was roll-pressed using two rolls at 60°C and a roll rotation speed of 3 rpm to manufacture a sheet-shaped positive electrode active material layer. The thickness of the manufactured sheet-shaped positive electrode active material layer was 200 μm. The manufactured positive electrode active material layer was a composite active material comprising a positive electrode active material, an electrolyte core surrounding the surface of the positive electrode active material, and a conductive material positioned on the surface of the core, embedded within a binder matrix.

[0203] The positive electrode was manufactured by positioning the positive electrode active material layer on an aluminum positive electrode current collector.

[0204] An all-solid-state battery was manufactured using the positive electrode, the negative electrode of Example 1, and the solid electrolyte of Example 1 in the same manner as in Example 1.

[0205] In the positive electrodes manufactured in Examples 1 to 7 and Comparative Examples 1 to 3, the contents of the positive electrode active material, binder matrix, electrolyte, and conductive material are shown in Table 1 below.

[0206] Cathode active material (wt%) Binder matrix (wt%) Electrolyte (wt%) Conductive material (wt%) Example 1851.4513.150.4 Example 2851.413.20.4 Example 3851.313.30.4 Example 4851.113.50.4 Example 585.20.813.60.4 Example 685.40.613.60.4 Example 785.60.413.60.4 Comparative example 185113.60.4 Comparative example 285113.60.4 Comparative example 3851 (using PTFE binder, wet)13.60.4 Comparative example 485113.60.4

[0207] Experimental Example 1) Evaluation of discharge capacity and initial efficiency

[0208] The all-solid-state batteries of Examples 1 to 7 and Comparative Examples 1 to 4 were charged and discharged once at 0.1 C, and the charge capacity and discharge capacity were measured. The measured discharge capacity results are shown in Table 2 below.

[0209] In addition, the ratio of discharge capacity to charge capacity was calculated, and the result is shown in Table 2 as the initial efficiency.

[0210] Discharge capacity (mAh / g) Initial efficiency (%) Example 1 17879.5 Example 2 17574.1 Example 3 17272.2 Example 4 16471.8 Example 5 18579.6 Example 6 19479.8 Example 7 20580.3 Comparative example 1 12440.1 Comparative example 2 20.8 10.4 Comparative example 3 11038.3 Comparative example 4 30.5 20.5

[0211] As shown in Table 2 above, the all-solid-state batteries of Examples 1 to 7 using a sheet-shaped positive electrode in which a composite active material of a positive electrode active material, a conductive core attached to the surface of the positive electrode active material, and an electrolyte surrounding the surface of the core are embedded in a binder matrix can be seen to exhibit high discharge capacity and excellent initial efficiency.

[0212] On the other hand, Comparative Example 1 using a sheet-type positive electrode of a positive electrode active material and a conductive material showed low discharge capacity and initial efficiency, and Comparative Example 2 using a sheet-type positive electrode of a positive electrode active material and an electrolyte showed significantly reduced discharge capacity and initial efficiency.

[0213] In addition, Comparative Example 3, which used a solvent in the manufacture of a sheet-shaped positive electrode, exhibited low discharge capacity and initial efficiency.

[0214] In addition, Comparative Example 4, which used a sheet-type positive electrode in which a composite active material of a positive electrode active material, an electrolyte core attached to the surface of the positive electrode active material, and a conductive material surrounding the core surface were embedded in a binder matrix, exhibited very low discharge capacity and initial efficiency.

[0215] 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. Binder matrix; and Containing a composite active material embedded within the above binder matrix, The above composite active material comprises a core including a positive electrode active material and a conductive material attached to the surface of the positive electrode active material; and an electrolyte layer positioned on the surface of the core. Cathode for all-solid-state batteries.

2. In paragraph 1, An all-solid-state battery positive electrode, wherein the binder matrix is ​​made of a fibrous binder.

3. In paragraph 2, The above binder is an all-solid-state battery cathode made of polytetrafluoroethylene, polyvinyl alcohol, polyvinylidene fluoride, or a combination thereof.

4. In paragraph 1, An all-solid-state battery positive electrode having a binder matrix content of 0.1 wt% to 10 wt% based on the total weight of the positive electrode.

5. In paragraph 1, An all-solid-state battery positive electrode having a content of the above-mentioned conductive agent of 0.1 wt% to 10 wt% based on the total weight of the positive electrode.

6. In paragraph 1, An all-solid-state battery cathode having an electrolyte content of 3 wt% to 20 wt% based on the total weight of the cathode.

7. In paragraph 1, An all-solid-state battery positive electrode, wherein the content of the above-mentioned challenging agent is smaller than the content of the above-mentioned electrolyte.

8. In paragraph 1, The above electrolyte is a positive electrode for an all-solid-state battery, which is a solid electrolyte.

9. In paragraph 1, The above positive electrode is an all-solid-state battery positive electrode in the form of a sheet.

10. In paragraph 1, The above positive electrode is an all-solid-state battery positive electrode made of a binder matrix in which a composite active material is embedded.

11. In paragraph 1, The above-mentioned conductive material is an all-solid-state battery positive electrode comprising a carbon-based material, a metal-based material, a conductive polymer, or a combination thereof.

12. In paragraph 1, The above positive electrode is prepared by mixing the positive electrode active material and the conductive material to produce a mixture; An electrolyte mixture is prepared by mixing the electrolyte into the above mixture; A binder mixture is prepared by mixing the electrolyte mixture, the conductive material, the electrolyte, and the binder; An all-solid-state battery positive electrode manufactured by a process of extruding the above binder mixture.

13. In paragraph 1, An all-solid-state battery positive electrode having a thickness of 70 ㎛ to 500 ㎛.

14. The positive electrode of any one of clauses 1 to 13; cathode; and A solid electrolyte layer positioned between the anode and cathode An all-solid-state battery comprising:

15. In paragraph 14, The above solid electrolyte is an all-solid-state battery which is a sulfide-based solid electrolyte.

16. In paragraph 14, An all-solid-state battery further comprising a lithium-containing layer formed between the current collector and the negative electrode coating layer during initial charging.

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