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

Abstract

The present invention relates to a negative electrode for an all-solid-state battery and an all-solid-state battery comprising same. The negative electrode for an all-solid-state battery comprises: a current collector; and a negative electrode active material layer located on the current collector and comprising a Si-carbon composite negative electrode active material, which contains Si nanoparticles, amorphous carbon, and crystalline carbon, a conductive material, a binder, and a solid electrolyte.

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 a cathode for an all-solid-state battery exhibiting excellent electrical conductivity and high-rate characteristics.

[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; and a negative electrode active material layer positioned on the current collector, the negative electrode active material layer including a Si-carbon composite negative electrode active material including Si nanoparticles, amorphous carbon and crystalline carbon, a conductive material, a binder and a solid electrolyte.

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

[0008] An all-solid-state battery cathode according to one embodiment can exhibit high capacity and excellent high-rate characteristics.

[0009] Figure 1 is a cross-sectional view schematically showing an all-solid-state battery according to one embodiment.

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

[0011] Figure 3 is a cross-sectional SEM photograph of a cathode manufactured according to Example 1.

[0012] Figure 4 is an X-ray diffraction measurement graph of a cathode manufactured according to Example 1.

[0013] 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.

[0014] 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.

[0015] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0020] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” the other part, but also cases where there is another part in between.

[0021] 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.

[0022] In one embodiment, the average particle size can be measured by various methods described above, for example, by means of a particle size analyzer.

[0023] In one embodiment, the thickness may be measured by SEM or TEM images of a cross-section, but is not limited thereto, and any method capable of measuring thickness in the art may be used. The thickness may be an average thickness.

[0024] In one embodiment, crystalline carbon and amorphous carbon can be classified by X-ray diffraction analysis. The crystalline carbon includes natural graphite and artificial graphite. Natural graphite refers to naturally occurring graphite obtained by separating from minerals, and when analyzed by X-ray diffraction, d002 is 3.350Å to 3.360Å, and artificial graphite refers to graphite made by graphitization, and when analyzed by X-ray diffraction, d002 is 3.355Å to 3.365Å. Amorphous carbon has a d002 of 3.34Å or less when analyzed by X-ray diffraction. The X-ray diffraction analysis (XRD) can be performed using an X-ray diffraction analyzer, for example, X'Pert (manufactured by Malvern Panalytical), with CuKα rays as a target line, and the monochrometer equipment can be removed to improve peak intensity resolution. The measurement conditions may be 2θ=10° to 80°, scan speed (° / S)=0.044 to 0.089, and step size (° / step)=0.013 to 0.039.

[0025] One embodiment provides an anode for an all-solid-state battery, comprising: a current collector; and a negative electrode active material layer positioned on the current collector, the negative electrode active material layer including a Si-carbon composite negative electrode active material including Si nanoparticles, amorphous carbon and crystalline carbon, a conductive material, a binder and a solid electrolyte.

[0026] In one embodiment, the mixing ratio of the Si-carbon composite negative electrode active material and the solid electrolyte may be a weight ratio of 80:20 to 99:1, or may be a weight ratio of 82:18 to 93:7. When the mixing ratio of the Si-carbon composite negative electrode active material and the solid electrolyte is within the above range, better high-rate characteristics may be exhibited.

[0027] In one embodiment, the content of the negative electrode active material may be 80 wt% to 95 wt%, 80 wt% to 93 wt%, or 80 wt% to 90 wt% based on 100 wt% of the total negative electrode active material layer. When the content of the negative electrode active material is within the above range, a higher capacity can be obtained.

[0028] In one embodiment, the content of the solid electrolyte may be 1 wt% to 17 wt%, 5 wt% to 17 wt%, or 6 wt% to 17 wt% based on 100 wt% of the total weight of the negative active material layer. When the content of the solid electrolyte is within the above range, the life characteristics of the battery can be further improved while minimizing side reactions between the negative active material and the solid electrolyte, and the conductivity of lithium ions can be improved, thereby further improving the rate characteristics.

[0029] In this way, when the mixing ratio of the Si-carbon composite negative electrode active material and the solid electrolyte satisfies the above range and each content also satisfies the above range, it can exhibit better high-rate characteristics and very low thickness expansion rate.

[0030] In one embodiment, the Si-carbon composite negative electrode active material may include a core comprising Si nanoparticles and crystalline carbon and an amorphous carbon coating layer positioned on the core. The core may also include secondary particles assembled with Si nanoparticles (primary particles) and crystalline carbon.

[0031] In another embodiment, the Si-carbon composite negative electrode active material may include an amorphous carbon matrix and a mixture of Si nanoparticles and crystalline carbon dispersed within the amorphous carbon matrix.

[0032] The particle size of the above Si nanoparticles may be 1 nm to 100 nm, 10 nm to 100 nm, or 10 nm to 50 nm. When the particle size of the silicon nanoparticles is within the above range, excessive volume expansion occurring during charge and discharge can be suppressed, and the disconnection of the conductive path due to particle fragmentation during charge and discharge can be prevented. In one embodiment, the particle size of the secondary particles can be appropriately controlled and need not be limited.

[0033] In one embodiment, the Si nanoparticles may be plate-shaped. When the Si nanoparticles are plate-shaped, surface cracks are less likely to occur during charge and discharge compared to when the Si nanoparticles are spherical, thereby reducing expansion of the Si nanoparticles, thereby further improving the initial efficiency and lifespan characteristics of the battery.

[0034] The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, carbon nanotubes, graphene, or a combination thereof. The crystalline carbon may be amorphous, plate-shaped, flake-shaped, spherical, or fibrous.

[0035] The particle size of the Si-carbon composite negative electrode active material may be 1 μm to 12 μm, 3 μm to 12 μm, or 5 μm to 10 μm. When the particle size of the Si-carbon composite negative electrode active material is within the above range, lithium ions can more easily diffuse into the negative electrode active material, and electrical resistance and rate characteristics can be further improved. In addition, since the specific surface area of ​​the negative electrode active material can be effectively suppressed from increasing excessively, side reactions of the solid electrolyte can be effectively suppressed.

[0036] In one embodiment, when the amorphous carbon is present as a coating layer positioned on the core, the thickness of the coating layer can be appropriately controlled, but for example, it can be present at a thickness of 5 nm to 100 nm, or can be present at a thickness of 10 nm to 100 nm.

[0037] In the above Si-carbon composite, the content of Si nanoparticles may be 20 wt% to 70 wt%, 30 wt% to 60 wt%, or 30 wt% to 50 wt% with respect to 100 wt% of the total Si-C composite.

[0038] The content of the crystalline carbon may be 25 wt% to 70 wt%, or 25 wt% to 60 wt%, based on 100 wt% of the total Si-carbon composite, and the content of the amorphous carbon may be 1 wt% to 20 wt%, or 5 wt% to 15 wt%.

[0039] According to one embodiment, the mixing ratio of the Si nanoparticles and the crystalline carbon may be a weight ratio of 80:20 to 20:80, a weight ratio of 70:30 to 30:70, or a weight ratio of 60:40 to 40:60. When the mixing ratio of the Si nanoparticles and the crystalline carbon is within the above range, the volume expansion of the Si nanoparticles can be further alleviated, thereby improving the cycle life characteristics, and there may be an advantage of complementing the conductivity of the active material.

[0040] In the above Si-carbon composite, the mixing ratio of the crystalline carbon and the amorphous carbon may be a weight ratio of 80:20 to 20:80, a weight ratio of 70:30 to 30:70, or a weight ratio of 60:40 to 40:60.

[0041] When the mixing ratio of crystalline carbon and amorphous carbon is within the above range, the rigidity of the negative active material can be further enhanced and the solid electrolyte can be effectively prevented from being directly exposed to the crystalline carbon, thereby suppressing deterioration.

[0042] 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 in the form of metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive polymers of polyphenylene derivatives; or mixtures thereof. The carbon nanotubes may be single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, or a combination thereof. In one embodiment, the conductive material may be a carbon-based material.

[0043] In one embodiment, the content of the conductive material may be 0.01 wt% to 1 wt%, 0.01 wt% to 0.5 wt%, 0.05 wt% to 0.3 wt%, or 0.05 wt% to 0.3 wt% with respect to 100 wt% of the negative electrode active material layer.

[0044] When the conductive material content is within the above range, the conductivity can be further improved while minimizing side reactions with the solid electrolyte, thereby improving the high-rate charge / discharge characteristics.

[0045] The above binder may be a non-aqueous binder, an aqueous binder, or a combination thereof.

[0046] The non-aqueous binder may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, acrylate polymer, or a combination thereof. The acrylate polymer may be butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0047] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0048] In one embodiment, the content of the binder may be 0.1 wt% to 5 wt%, 0.5 wt% to 5 wt%, or 0.5 wt% to 3 wt%.

[0049] The above binder may be a cellulose-based compound, and the cellulose-based compound may be used together with the aqueous binder. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li. The cellulose-based compound may function as a binder or as a thickener capable of providing viscosity. Accordingly, the cellulose-based compound may be used in an appropriate amount within the binder amount, but may be, for example, 0.1 to 3 parts by weight based on 100 parts by weight of the Si-carbon composite.

[0050] 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. In one embodiment, the solid electrolyte may be a sulfide-based solid electrolyte. In one embodiment, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte.

[0051] The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m and n are integers greater than or equal to 0 and less than or equal to 12, respectively, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are integers greater than or equal to 0 and less than or equal to 12, respectively; M is one of P, Si, Ge, B, Al, Ga In), Li a M b P c S d A e (a, b, c, d and e are each integers greater than or equal to 0 and less than or equal to 12, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I). The sulfide-based solid electrolyte may be, for example, Li 7-x PS 6-x F x (0≤x≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) or Li 7-x PS 6-x I x (0≤x≤2) may be.

[0052] Specific examples of sulfide-based solid electrolytes include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS4.8 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 , (Li 5.69 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 combinations thereof, but are not limited thereto.

[0053] 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.

[0054] 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.

[0055] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 , 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.

[0060] The thickness of the negative electrode active material layer may be, for example, 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, or 1 µm to 50 µm, but is not limited thereto.

[0061] The current collector may be, for example, a copper (Cu) foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, or a combination thereof. The thickness of the current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0062] 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.

[0063] 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.

[0064] The above negative electrode can be manufactured by mixing a Si-carbon composite negative electrode active material, a conductive material, a binder, and a solid electrolyte in an organic solvent to manufacture a negative electrode active material layer composition, and applying, drying, and rolling the negative electrode active material layer composition to a current collector.

[0065] The organic solvent may be N-methyl pyrrolidone, octyl acetate, or a combination thereof.

[0066] The above binder can be used in a solution state, and the solvent can be isobutyryl isobutyrate, octyl acetate, xylene, toluene, benzene, hexane, or a combination thereof.

[0067] All-solid-state battery

[0068] Another embodiment provides an all-solid-state battery comprising the above negative electrode.

[0069] The above-mentioned all-solid-state battery includes a positive electrode, a negative electrode, and a solid electrolyte layer positioned between the positive electrode and the negative electrode. The negative electrode may be a negative electrode according to one embodiment.

[0070] [anode]

[0071] 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.

[0072] 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 bO 2-c D 1 c (0.90≤a ≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a HAVE BEEN 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 O2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b E 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 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.

[0073] 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 1is 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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 active material 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%.

[0081] The above positive electrode active material layer may further include a binder and / or a conductive material.

[0082] 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.

[0083] 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.

[0084] 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 nanotube; 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.

[0085] 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.

[0086] The above 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 negative electrode active material layer, and may be the same as or different from the solid electrolyte included in the negative electrode active material layer.

[0087] With respect to the total weight 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%. In addition, with respect to the total weight of the positive electrode active material and the solid electrolyte in the positive electrode active material layer, 65 wt% to 99 wt% of the positive electrode active material and 1 wt% to 35 wt% of the solid electrolyte may be included, for example, 80 wt% to 90 wt% of the positive electrode active material and 10 wt% to 20 wt% of the solid electrolyte may be included. 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. The above solid electrolyte may be included in an amount of 0.1 to 10 wt% to 30 wt% based on 100 wt% of the total positive electrode active material layer.

[0088] 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.

[0089] Solid electrolyte layer

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

[0091] In one embodiment, the inorganic solid electrolyte and / or solid polymer electrolyte, such as the sulfide-based solid electrolyte, sulfide-based solid electrolyte, oxide-based solid electrolyte, and halide-based solid electrolyte, are as described above.

[0092] The above solid electrolyte is in the form of particles, and the average particle diameter (D50) may be 5.0 μm or less, for example, 0.1 μm to 5.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 0.5 μm to 2.0 μm, or 0.5 μm to 1.0 μm.

[0093] 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.

[0094] 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.

[0095] The solid electrolyte layer may further comprise an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] In one embodiment, the thickness of the solid electrolyte layer may be 10 μm to 600 μm, 50 μm to 600 μm, or 100 μm to 300 μm.

[0104] Elastic layer

[0105] 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.

[0106] 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.

[0107] <Method for manufacturing an all-solid-state battery>

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] FIG. 1 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 1, 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 coating layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode collector (201) are laminated is housed in a case (500) such as a pouch. The all-solid-state battery (100) may further include an elastic layer on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 1 illustrates one electrode assembly including a negative electrode (400), a solid electrolyte layer (300), and a positive electrode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0113] Fig. 2 schematically illustrates an all-solid-state battery according to another embodiment. The all-solid-state battery (100) illustrated in Fig. 2 includes a positive electrode (200) including a positive electrode current collector (201) and a positive electrode active material layer (203), a negative electrode (400) including a negative electrode current collector (401), a negative electrode coating layer (403), and a solid electrolyte (300) positioned between the positive electrode (200) and the negative electrode (400), and includes a battery case (500) in which these are housed, and further includes a lithium precipitation layer (405') between the negative electrode current collector (401) and the negative electrode coating layer (403). When the all-solid-state battery is charged, the lithium precipitation layer can be formed by lithium ions being released from the positive electrode active material and deposited on the negative electrode current collector (401').

[0114] Hereinafter, examples and comparative examples of the present invention will be described. The following examples are merely exemplary of the present invention, and the present invention is not limited to the following examples.

[0115] (Example 1)

[0116] (1) Cathode manufacturing

[0117] A negative electrode active material layer composition was prepared by mixing a dry-mixed mixture of 85 wt% of a Si-carbon composite and 11.9 wt% of an argyrodite-type solid electrolyte Li6PS5Cl, an isobutylyl isobutylate binder solution (acrylate polymer content: 3 wt%) containing an acrylate polymer, and 0.1 wt% of a single-walled carbon nanotube conductive agent in an octyl acetate solvent.

[0118] The above Si-carbon composite was used as an assembled body of plate-shaped silicon nanoparticles with an average size (D50) of 100 nm and artificial graphite, which had a soft carbon coating layer. At this time, the content of silicon nanoparticles was 40 wt% with respect to the total weight of the silicon-carbon composite, the content of artificial graphite was 30 wt%, and the content of the soft carbon was 30 wt%.

[0119] The above negative electrode active material layer composition was applied to a stainless steel current collector, dried, and rolled to manufacture a negative electrode.

[0120] (2) Manufacturing of solid electrolyte layer

[0121] A solid electrolyte solution was prepared by adding crystalline argyrodite-type solid electrolyte Li6PS5Cl to an isobutylyl isobutylate binder solution containing an acrylate polymer (solid content: 50 wt%, mixing ratio of the solid electrolyte and binder: 98.7:1.3 wt ratio).

[0122] The above solid electrolyte solution was applied to a heterogeneous polytetrafluoroethylene film and dried to produce a solid electrolyte layer having a thickness of 100 μm.

[0123] (3) Manufacturing of anode

[0124] LiNi 0.9 Co 0.05 Mn 0.05A positive electrode active material layer composition was prepared by mixing an O2 positive electrode active material, a crystalline argyrodite-based solid electrolyte Li6PS5Cl, a butyl acrylate binder, and a single-walled carbon nanotube conductive material in an octyl acetate solvent at a weight ratio of 85.0:13.44:0.56:1.0. This positive electrode active material layer composition was applied to an aluminum current collector and dried to prepare a positive electrode including a positive electrode active material layer having a thickness of approximately 200 μm.

[0125] (4) Manufacturing of all-solid-state full cells

[0126] The manufactured negative electrode, solid electrolyte layer, and positive electrode were sequentially laminated, and a pressure of 490 MPa was applied to manufacture an all-solid-state battery (full cell).

[0127] (Example 2)

[0128] A negative electrode active material layer composition was prepared by mixing 84.8 wt% of a Si-carbon composite, 11.9 wt% of an argyrodite-type solid electrolyte Li6PS5Cl, an isobutylyl isobutylate solution containing an acrylate polymer (acrylate polymer content: 3.2 wt%), and 0.1 wt% of a single-walled carbon nanotube conductive agent in an octyl acetate solvent.

[0129] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the negative electrode active material layer composition was used.

[0130] (Example 3)

[0131] A negative electrode active material layer composition was prepared by mixing 90 wt% of a Si-carbon composite, 6.9 wt% of an argyrodite-type solid electrolyte Li6PS5Cl, an isobutylyl isobutylate solution containing an acrylate polymer (acrylate polymer content: 3 wt%), and 0.1 wt% of a single-walled carbon nanotube conductive agent in an octyl acetate solvent.

[0132] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the negative electrode active material layer composition was used.

[0133] (Example 4)

[0134] A negative electrode active material layer composition was prepared by mixing 80 wt% of a Si-carbon composite, 16.9 wt% of an argyrodite-type solid electrolyte Li6PS5Cl, an isobutylyl isobutylate solution containing an acrylate polymer (acrylate polymer content: 3 wt%), and 0.1 wt% of a single-walled carbon nanotube conductive agent in an octyl acetate solvent.

[0135] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the negative electrode active material layer composition was used.

[0136] (Comparative Example 1)

[0137] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that Si was used instead of the Si-carbon composite.

[0138] (Comparative Example 2)

[0139] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 2, except that Si was used instead of the Si-carbon composite.

[0140] (Comparative Example 3)

[0141] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 3, except that Si was used instead of the Si-carbon composite.

[0142] (Comparative Example 4)

[0143] A negative electrode active material layer composition was prepared by mixing 85.1 wt% of a Si-carbon composite, 11.9 wt% of an argyrodite-type solid electrolyte Li6PS5Cl, and an isobutylyl isobutylate solution (acrylate polymer content: 3 wt%) containing an acrylate polymer in an octyl acetate solvent.

[0144] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the negative electrode active material layer composition was used.

[0145] Experimental Example 1) SEM Photograph

[0146] A cross-sectional SEM image of the cathode manufactured according to Example 1 is shown in Fig. 3. As shown in Fig. 3, it can be seen that the cathode coating layer of Example 1 has a uniform presence of a Si-carbon composite and a solid electrolyte.

[0147] Experimental Example 2) X-ray diffraction evaluation

[0148] The X-ray diffraction peaks of the negative electrode manufactured according to the above Example 1 were measured using CuKα rays. The results are shown in Fig. 4. As shown in Fig. 4, it can be seen that the manufactured negative electrode coating layer includes crystalline carbon, silicon, and a solid electrolyte.

[0149] Experimental Example 3) Evaluation of Thickness Increase Rate

[0150] The all-solid-state batteries manufactured according to Examples 1 to 4 and Comparative Examples 1 to 4 were subjected to two chemical charge-discharge cycles at 0.1 C, followed by 23 full charge-discharge cycles at 0.33 C. The ratio of the battery thickness after full charge to the thickness of the battery subjected to chemical charge-discharge and the battery thickness ratio after full discharge were determined. The results are presented in Table 2 below as thickness expansion ratios.

[0151] Experimental Example 4) Rate Evaluation

[0152] The all-solid-state batteries manufactured according to Examples 1 to 4 and Comparative Examples 1 to 4 were charged and discharged once each at 0.2 C, 0.33 C, 0.5 C, and 1 C, and the discharge capacity was obtained. The results are shown in Table 3 below.

[0153] The cathode compositions of Examples 1 to 4 and Comparative Examples 1 to 4 are summarized and shown in Table 1 below.

[0154] Negative active material content (weight %) Solid electrolyte content (weight %) Negative active material: solid electrolyte weight ratio Conductive material content (weight %) Binder content (weight %) Example 185 11.98 7.8:12.3 0.13 Example 284.8 11.98 7.9:12.10.33 Example 39 06.99 2.9:7.10.13 Example 48 016.98 2.6:17.4 0.13 Comparative example 185 11.98 7.7:12.3 0.13 Comparative example 284.8 11.98 7.9:12.10.33 Comparative example 39 06.99 2.9:7.10.13 Comparative example 485.11 1.98 7.7:12.303

[0155]

[0156] Cathode active material: solid electrolyte weight ratio thickness expansion rate (%) full charge full discharge Example 187.7:12.3 13.6 9.9 Example 287.9:12.1 14.3 12.1 Example 392.9:7.1 14.6 10.7 Example 482.6:17.4 13.29.4 Comparative example 187.7:12.3 20.115.0 Comparative example 287.9:12.1 2.3 16.9 Comparative example 392.9:7.1 21.7 16.3 Comparative example 487.7:12.3 25.5 19.8

[0157]

[0158] As shown in Table 2 above, it can be seen that the thickness increase rate of Examples 1 to 4 is much lower than that of Comparative Examples 1 to 4.

[0159]

[0160] Negative active material: solid electrolyte weight ratio 0.2C (mAh / g) 0.33C (mAh / g) 0.5C (mAh / g) 1C (mAh / g) Example 187.7:12.3 139 115 7552 Example 287.9:12.1 128 105 6948 Example 392.9:7.1 142 113 7146 Example 482.6:17.4 130 109 7255 Comparative example 187.7:12.3 115 926041 Comparative example 287.9:12.1 198 65539 Comparative example 392.9:7.1 133 1016037 Comparative example 488.2:11.8 1229 65632

[0161]

[0162] As shown in Table 3 above, the batteries of Examples 1 to 4 using Si-carbon composite negative electrode active materials showed higher discharge capacities at all rates than the batteries of Comparative Examples 1 to 4 using Si active materials.

[0163] 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; and A negative electrode active material layer positioned on the current collector and including a Si-carbon composite negative electrode active material including Si nanoparticles, amorphous carbon and crystalline carbon, a conductive material, a binder and a solid electrolyte. A cathode for an all-solid-state battery comprising:

2. In paragraph 1, An all-solid-state battery negative electrode in which the Si-carbon composite negative electrode active material and the solid electrolyte are mixed in a weight ratio of 80:20 to 99:

1.

3. In paragraph 1, An all-solid-state battery negative electrode in which the content of the above-mentioned conductive material is 0.01 wt% to 1 wt% with respect to 100 wt% of the above-mentioned negative electrode active material layer.

4. In paragraph 1, An all-solid-state battery negative electrode in which the content of the negative active material is 80 to 95 wt% based on 100 wt% of the total negative active material layer.

5. In paragraph 1, An all-solid-state battery negative electrode having a content of the solid electrolyte of 1 to 17 wt% based on 100 wt% of the total negative electrode active material layer.

6. In paragraph 1, An all-solid-state battery negative electrode having the above Si nanoparticles having a particle size of 1 nm to 100 nm.

7. In paragraph 1, An all-solid-state battery negative electrode having a particle size of the Si-carbon composite negative electrode active material of 1 μm to 12 μm.

8. In paragraph 1, The above Si-carbon composite negative electrode active material is an all-solid-state battery negative electrode including a core including Si nanoparticles and crystalline carbon and an amorphous carbon coating layer positioned on the core.

9. In paragraph 1, The above Si-carbon composite negative electrode active material is an anode for an all-solid-state battery comprising an amorphous carbon matrix and a mixture of Si nanoparticles and crystalline carbon dispersed within the amorphous carbon matrix.

10. In paragraph 1, The above Si nanoparticles are plate-shaped negative electrodes for all-solid-state batteries.

11. In paragraph 1, An all-solid-state battery negative electrode in which the Si-carbon composite has a mixing ratio of the Si nanoparticles and the crystalline carbon of 80:20 to 20:80 by weight.

12. In paragraph 1, An all-solid-state battery negative electrode, wherein the Si-carbon composite has a mixing ratio of the crystalline carbon and the amorphous carbon of 80:20 to 20:80 by weight.

13. In paragraph 1, The above conductive material is a carbon-based material such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, or carbon nanotube; a metal-based material in the form of metal powder or metal fiber of copper, nickel, aluminum, or silver; a conductive polymer of a polyphenylene derivative; or a mixture thereof, for an all-solid-state battery negative electrode.

14. In paragraph 13, The above-mentioned conductive material is a carbon-based material for an all-solid-state battery.

15. In paragraph 1, The above solid electrolyte is a sulfide-based solid electrolyte, and is an all-solid-state battery negative electrode.

16. In paragraph 15, The above sulfide-based solid electrolyte is an all-solid-state battery negative electrode that is an argyrodite-type sulfide-based solid electrolyte.

17. The cathode of any one of paragraphs 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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