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

Abstract

The present invention relates to a negative electrode for an all-solid-state battery and an all-solid-state battery including same. The negative electrode for an all-solid-state battery comprises: a current collector having a recess formed therein; a metal filled in the recess; and a carbon layer positioned on one side of the current collector so as to cover the recess.

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] The recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for compact, lightweight, and relatively high-capacity secondary batteries. In particular, lithium secondary batteries are attracting attention as power sources for portable devices due to their lightweight design and high energy density. Accordingly, active research and development is underway to improve the performance of lithium secondary batteries.

[0003] Among lithium secondary batteries, an all-solid-state battery is a battery composed entirely of solid materials, specifically a battery that uses a solid electrolyte.

[0004] One embodiment provides a negative electrode for an all-solid-state battery that can effectively suppress lithium dendrite formation.

[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 having a groove formed therein; a metal filled inside the groove; and a carbon layer including a carbon-based material positioned on one surface of the current collector so as to cover the groove.

[0007] Another embodiment provides an all-solid-state battery comprising: a cathode including a current collector and a cathode coating layer positioned on one surface of the current collector; an anode; and a solid electrolyte layer positioned between the cathode and the anode, wherein the cathode is the cathode.

[0008] The above solid electrolyte may be a sulfide-based solid electrolyte.

[0009] An anode for an all-solid-state battery according to an embodiment can provide an all-solid-state battery that can effectively prevent lithium dendrites during charge and discharge.

[0010] Figure 1 is a schematic drawing showing the structure of a negative electrode for an all-solid-state battery according to one embodiment.

[0011] Figure 2 is a schematic drawing showing the structure of a negative electrode for an all-solid-state battery according to another embodiment.

[0012] Figure 3 is a schematic drawing showing the structure of a negative electrode for an all-solid-state battery according to another embodiment.

[0013] Figure 4 is a schematic drawing showing the structure of a negative electrode for an all-solid-state battery according to another embodiment.

[0014] Figure 5 is a schematic diagram schematically showing the charge / discharge state of an all-solid-state battery according to one embodiment.

[0015] Figure 6 is a schematic diagram schematically showing an all-solid-state battery according to another embodiment.

[0016] 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.

[0017] 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.

[0018] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0019] It should be understood that the terms "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0020] 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.

[0021] 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.

[0022] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0023] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there is another part in between.

[0024] 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.

[0025] "Thickness" may be measured, for example, from photographs taken with an optical microscope such as a scanning electron microscope.

[0026] In one embodiment, thickness may mean a size in a direction substantially perpendicular to the longitudinal direction.

[0027] An anode for an all-solid-state battery according to one embodiment includes a substrate having a groove formed therein; a metal filled inside the groove; and a carbon layer positioned on one surface of the substrate so as to cover the groove.

[0028] To explain this in detail, the cathode according to one embodiment has a groove formed in the substrate, a metal filled inside the groove, and a carbon layer positioned to cover the groove.

[0029] The above all-solid-state battery refers to a battery in which, when charged, lithium ions are released from the positive active material, pass through the solid electrolyte, and move toward the negative electrode, resulting in lithium precipitation and deposition on the negative electrode current collector, thereby forming a lithium-containing layer between the current collector and the negative electrode coating layer. In such an all-solid-state battery, the lithium-containing layer may be referred to as a precipitation-type negative electrode.

[0030] The above-mentioned negative electrode coating layer is generally formed as a single layer by mixing metal and amorphous carbon. In an all-solid-state battery, after laminating the negative electrode, electrolyte, and positive electrode, a significant amount of pressure may be applied to the entire negative electrode within the battery during the pressurizing process to seal them tightly. Therefore, lithium precipitation that moves toward the negative electrode during charge and discharge may occur anywhere on the negative electrode surface, and lithium precipitation may occur excessively in a specific area. Excessively precipitated lithium, such as excessively grown lithium dendrites, may cause a problem by penetrating the electrolyte layer and contacting the positive electrode. Even if a separate carbon layer is formed on the negative electrode coating layer, the prevention effect may be minimal if lithium precipitation occurs excessively in a specific area of ​​the negative electrode surface.

[0031] According to one embodiment, an anode for an all-solid-state battery has metal and carbon separately present in a current collector, and in particular, a metal is positioned inside a groove formed in the current collector, and a carbon layer is formed on one surface of the current collector while surrounding the groove.

[0032] When manufacturing an all-solid-state battery including such a negative electrode, since the pressure generated during the pressurizing process is greater in an area where no grooves are formed than inside the grooves, lithium ions that move toward the negative electrode during charge and discharge are mainly precipitated and deposited under the metal inside the grooves. Therefore, even if lithium dendrites are formed, they may be formed mainly inside the grooves. Therefore, even if a large number of lithium dendrites are formed, the distance from the electrolyte can be far or the distance from the electrolyte can be maintained constant, so that the problem of lithium dendrites penetrating the electrolyte and directly contacting the positive electrode, causing a short circuit, can be prevented. This effect of suppressing the occurrence of a short circuit due to lithium dendrites can be greater in one embodiment in which lithium precipitation and growth occur inside the grooves rather than in forming a separate carbon layer on the negative electrode coating layer.

[0033] In one embodiment, the metal may completely fill the inside of the groove, or may only partially fill the inside. For example, the metal (5) may be positioned in the groove so as to be lower than the height of the groove in the thickness direction of the current collector (3) of the negative electrode (1), as shown in Fig. 1. The carbon layer (7) may be formed on one surface of the current collector (9) so as to cover the groove and the current collector. In this case, an empty space may be positioned between the metal (5) and the carbon layer (7).

[0034] In addition, the metal may be positioned convexly while completely filling the inside of the groove. For example, as shown in Fig. 2 regarding the negative electrode (1a) of another embodiment, the metal (5a) may be positioned so as to completely fill the inside of the groove formed in the current collector (3a) and be positioned higher than the height of the groove in the thickness direction of the current collector. In this case, the carbon layer (7a) may be formed to cover both the current collector (3a) and the metal (5a).

[0035] According to another embodiment, in the negative electrode (1b) of FIG. 3, the metal (5b) may be positioned on the surface of the current collector (3b) while filling the groove of the current collector (3b). In this case, the metal (5b) positioned on the surface of the current collector (3b) may be positioned substantially flat. Additionally, a carbon layer (7b) may be formed to cover the metal (5b).

[0036] According to another embodiment, as in the negative electrode (1c) shown in FIG. 4, the metal (5c) may be positioned on the surface of the current collector (3c) while being positioned on the lower surface and the peripheral surface of the groove, and the carbon layer (7c) may be positioned on the surface of the current collector (3c) while surrounding the metal (5c), for example, having a certain thickness.

[0037] In this way, as long as the metal is positioned within the groove formed in the current collector and is located separately from the carbon layer, it does not matter in what form it is positioned on the current collector.

[0038] However, it is appropriate for the metal to be positioned lower than the height of the groove in the thickness direction of the current collector, as this can more effectively prevent the problem of lithium dendrites penetrating the solid electrolyte and making direct contact with the positive electrode.

[0039] In one embodiment, the metal may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof. According to one embodiment, the metal may be Ag. When the cathode includes the metal, it is suitable because it can improve electrical conductivity.

[0040] The above metal may be a nanoparticle, and the size of the metal nanoparticle may be, for example, an average size of several tens of nm to several hundred μm, and there is no need to limit it.

[0041] In one embodiment, the average diameter of the groove may be 200 μm or less, may be 1 μm to 200 μm, or may be 10 μm to 200 μm. In one embodiment, the average diameter of the groove may be the length of the major axis among the length and width measured using an SEM. When the average diameter of the groove is within the above range, lithium dendrites generated during charge and discharge can be sufficiently located inside the groove, which is more appropriate.

[0042] The thickness of the groove may be 90% or less, more than 0%, 90% or less, or 20% to 80% of the thickness of the current collector 100%. In this case, the thickness of the groove may refer to the depth of the groove. When the thickness of the groove is within the above range, lithium dendrites generated during charging and discharging can be sufficiently located inside the groove, which is more appropriate.

[0043] The above home area may be 90% or less of the area of ​​the current collector, and may be 10% to 90% of the area of ​​the current collector.

[0044] When the metal is filled only partially within the groove, the metal may be filled within the groove in an area of ​​50% or less, 5% to 50% of the total area within the groove. When the metal is filled within the groove in the area % described above, the groove forming effect can be more appropriately obtained.

[0045] In the cathode according to one embodiment, the content of the metal may be 3 wt% to 40 wt%, 3 wt% to 30 wt%, 4 wt% to 25 wt%, 5 wt% to 20 wt%, or 5 wt% to 15 wt%, based on 100 wt% of the total content of the metal and the carbon-based material.

[0046] Additionally, the carbonaceous material may be present in an amount of 60 wt% to 97 wt%, 70 wt% to 97 wt%, 75 wt% to 96 wt%, 80 wt% to 95 wt%, or 85 wt% to 95 wt%, based on 100 wt% of the total content of the metal and the carbonaceous material.

[0047] The carbonaceous material included in the carbon layer may include amorphous carbon or crystalline carbon. 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 amorphous, plate-shaped, flake-shaped, spherical, or fibrous natural graphite, artificial graphite, carbon nanotubes, graphene, or a combination thereof.

[0048] The amorphous carbon may be a single particle, or may be an assembly having a secondary particle form in which primary particles are assembled. When the amorphous carbon is a single particle, it may be an amorphous carbon particle having an average particle diameter of 100 nm or less, for example, a nano-size of 10 nm to 100 nm.

[0049] Additionally, when the amorphous carbon is an assembly, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0050] In one embodiment, the particle size of the primary particles may be from 20 nm to 90 nm, from 20 nm to 80 nm, or from 30 nm to 80 nm.

[0051] In one embodiment, the particle size of the secondary particles may be 1 μm to 15 μm, 2 μm to 10 μm, or 2 μm to 7 μm.

[0052] 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.

[0053] The above carbon layer may further include a binder.

[0054] The above binder may include a non-aqueous binder, an aqueous binder, or a combination thereof.

[0055] The non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or combinations thereof.

[0056] The above-mentioned aqueous binder may include styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, acrylic rubber, butyl rubber, fluoroelastomer, or a combination thereof.

[0057] The negative electrode binder may include a cellulose-based compound. In addition, the negative electrode binder may include both the aqueous binder and the cellulose-based compound. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. The alkali metal may be Na, K, or Li. The cellulose-based compound may also function as a thickener capable of imparting viscosity in addition to being a binder.

[0058] 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.

[0059] The binder may be present in an amount of 1 to 40 wt% relative to 100 wt% of the total carbon layer. The binder may also be present in an amount of 1 to 15 wt% relative to 100 wt% of the total carbon layer, for example, the binder may be present in an amount of 1 to 14 wt%, 1 to 10 wt%, 1 to 8 wt%, or 1 to 5 wt% relative to 100 wt% of the total carbon layer.

[0060] When the above binder is included in the carbon 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.

[0061] The above carbon layer may further include additives such as fillers, dispersants, and ionic conductive agents, for example. As the fillers, dispersants, and ionic conductive agents that can be included in the carbon layer, known materials generally used in all-solid-state batteries may be used.

[0062] The thickness of the above carbon layer may be 1 µm to 100 µm.

[0063] 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 current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0064] The current collector may further include a thin film formed on the substrate using the metal. The thin film includes 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 can be formed, thereby further improving the cycle life of the all-solid-state battery. The thickness of the 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 thickness of the thin film is within the above range, the cycle life characteristics can be further improved.

[0065] A cathode according to an embodiment can be manufactured by the following manufacturing process.

[0066] A metal is deposited on a current collector having a groove formed therein, so that the metal is positioned within the groove. The method for forming the groove on the current collector may be performed by any method capable of forming a groove, such as chemical etching or a physical method. The deposition process may be chemical vapor deposition, physical vapor deposition, or a combination thereof. The deposition process may be performed so that the metal is positioned lower than the height of the groove, as in FIG. 1, or so that the metal is positioned convexly, as in FIG. 2, completely filling the inside of the groove.

[0067] Next, a carbon layer is formed on the obtained product. The carbon layer forming process can be formed by applying and drying a carbon layer composition including a carbon-based material, a binder, and a solvent to the product. The binder is as described above, and the solvent can be an organic solvent such as N-methyl pyrrolidone when a non-aqueous binder is used as the binder, and water can be used when an aqueous binder is used as the binder. When the metal is formed lower than the height of the groove, when forming the carbon layer, a structure such as FIG. 1 can be formed in which a portion of the inside of the groove is not filled with the carbon layer.

[0068] According to one embodiment, the negative electrode may further include a lithium-containing layer between the current collector and the negative electrode coating layer.

[0069] Since the lithium-containing layer is a metal layer containing lithium, it can act as a lithium reservoir, for example.

[0070] The above lithium-containing layer may be a lithium deposition layer in which lithium ions released from the positive electrode active material during charging move toward the negative electrode and are deposited on the surface of the current collector. In this case, the lithium-containing layer may be referred to as a lithium deposition layer.

[0071] The above lithium-containing layer may be a layer containing lithium or a lithium alloy.

[0072] The lithium alloy may include lithium and a metal alloyable with lithium. The metal alloyable with lithium may be Ag, Au, Mg, In, Si, Sn, Al, Ge, Pb, Bi, Sb, a Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, and is not Si), a Sn-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, and is not Sn), etc. The above element Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0073] 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, it may have the advantage of being able to appropriately perform the role of a lithium storage tank and further improving the lifespan.

[0074] If the above lithium-containing layer is a lithium precipitation layer, this lithium precipitation layer can be formed when lithium ions are released from the positive electrode active material during charging after manufacturing an all-solid-state battery, pass through the solid electrolyte, and move toward the negative electrode, and as a result, lithium is precipitated and deposited on the negative electrode current collector.

[0075] The above charging process may be a combustion process performed once to three times at 0.05C to 1C at about 25°C to 50°C. When discharging, lithium contained in the lithium-containing layer is ionized and moves toward the positive electrode, so this lithium can be used as an anode active material.

[0076] In one embodiment, since the lithium-containing layer is positioned between the current collector and the negative electrode active material 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.

[0077] Another embodiment provides an all-solid-state battery comprising the above-described cathode, a solid electrolyte layer, and a cathode.

[0078] The solid electrolyte included in the above solid electrolyte 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. In one embodiment, the solid electrolyte may be a sulfide-based solid electrolyte, and for example, may be an argyrodite-type sulfide-based solid electrolyte. Such sulfide-based solid electrolytes are suitable because they have superior ion conductivity compared to other solid electrolytes such as oxide-based solid electrolytes, and can exhibit superior life characteristics over a wider operating range.

[0079] The above sulfide-based solid electrolytes are Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), 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). 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, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, 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.

[0080] The above sulfide-based solid electrolyte can be obtained, for example, 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. Here, other components such as SiS2, GeS2, and B2S3 can be further included to further improve the ionic conductivity. 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 a solution method is used, the starting materials can be 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.

[0081] The above sulfide-based solid electrolyte may be amorphous or crystalline, or may be a mixture of the two. Of course, the sulfide-based solid electrolyte may use a commercially available solid electrolyte. Of course, the sulfide-based solid electrolyte may also use a commercially available sulfide-based solid electrolyte.

[0082] The above oxide-based inorganic 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.

[0083] 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.

[0084] 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.

[0085] The above solid polymer electrolytes include, for example, polyethylene oxide, poly(diallyldimethylammonium)trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, and Li3PO. 4· Li2S · SiS2, Li2S · GeS 2· Ga2S3, Li2O · 11Al2O3, Na2O · 11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3(0.1≤x≤0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li1+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.

[0086] 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 ㎛.

[0087] The above solid electrolyte layer may further include a binder. At this time, the binder may be, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, 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.

[0088] 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.

[0089] The above positive electrode includes a positive electrode current collector and a positive electrode active material layer positioned on one surface of the positive electrode current collector.

[0090] The above-mentioned 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. 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-cCo b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Co c Mr d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0 ≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1); Li a NiG b O2( 0.90≤a≤1.8, 0.001≤b≤0.1); Lia 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.

[0091] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1 is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0092] 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.

[0093] 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.

[0094] 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).

[0095] Furthermore, when the cathode active material includes 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.

[0096] Here, examples of the shape of the positive electrode active material include spherical, elliptical, and other particle shapes. Furthermore, 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 for existing all-solid-state secondary batteries. Furthermore, the content of the positive electrode active material in the positive electrode active material layer is also not particularly limited, and may be within the range applicable to positive electrode layers for existing all-solid-state secondary batteries.

[0097] 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 the above-described solid electrolyte, and in this case, it may be the same as or different from the solid electrolyte included in the solid electrolyte layer. The solid electrolyte may be included in an amount of 10 wt% to 30 wt% based on the total weight of the positive electrode active material layer.

[0098] The above positive electrode 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.

[0099] In addition, in addition to the aforementioned positive electrode active material and solid electrolyte, additives such as a conductive agent, a binder, a filler, a dispersant, and an ionic conductive agent can be appropriately mixed into the positive electrode active material layer.

[0100] As fillers, dispersants, and ionic conductive agents that can be contained in the positive electrode active material layer, the same additives as those incorporated into the negative electrode active material layer described above may be used. In this case, the conductive agent may be present in an amount of 1 wt% to 10 wt% based on the total weight of the positive electrode active material layer.

[0101] Examples of binders that can be included in the positive electrode active material layer include styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene.

[0102] The thickness of the positive electrode active material layer may be 90 µm to 200 µm. For example, the thickness of the positive electrode active material layer may be 90 µm to 190 µm, 110 µm to 190 µm, or 120 µm to 180 µm. As described above, since the thickness of the positive electrode active material layer is thicker than the thickness of the negative electrode active material layer, the capacity of the positive electrode is greater than the capacity of the negative electrode.

[0103] The above positive electrode can be manufactured by forming a positive electrode active material layer on a positive electrode current collector by dry or wet coating.

[0104] 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.

[0105] 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.

[0106] FIG. 5 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 5, 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 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. 5 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.

[0107] Fig. 6 schematically illustrates the structure of an all-solid-state battery according to another embodiment. This may be, for example, an all-solid-state battery in a charged state. The all-solid-state battery (100) 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 layer (300) positioned between the positive electrode (200) and the negative electrode (400'), and includes a battery case (500) in which these are accommodated.

[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, warm isostatic pressing, roll pressing, or plate pressing.

[0110] 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.

[0111] (Example 1)

[0112] (1) Manufacturing of cathode

[0113] A groove with an average diameter of 200 μm was formed physically on a stainless steel foil current collector to a thickness (depth) of 50% of the current collector thickness of 100%. An Ag layer was deposited on the grooved stainless steel foil current collector by a chemical vapor deposition method to form a metal layer in which Ag was deposited entirely within the groove.

[0114] Next, a carbon layer slurry was prepared by mixing 96 wt% of carbon black having a specific surface area of ​​55 m2 / g and an average size of 35 nm, 2 wt% of carboxymethyl cellulose, and 4 wt% of styrene-butadiene rubber in water.

[0115] After coating the above carbon layer slurry on a stainless steel foil current collector having a metal layer formed thereon, vacuum drying was performed at 80°C to manufacture a negative electrode including a metal layer and a carbon layer on a stainless steel foil current collector having a groove formed thereon.

[0116] (2) Preparation of solid electrolyte layer

[0117] 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.

[0118] 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.

[0119] (3) Manufacturing of anode

[0120] LZO (Li-doped zinc oxide) coated cathode active material (LiNi 0.9 Mn 0.05 Co 0.05 O2) Based on 100 parts by weight, a mixture was prepared by mixing 17.6 parts by weight of argyrodite-type solid electrolyte Li6PS5Cl, 3.53 parts by weight of conductive material CNF (Carbon Nano Fiber), and 1.76 parts by weight of binder polytetrafluoroethylene (PTFE). In the mixture, the weight ratio of the positive electrode active material solid electrolyte, conductive material, and binder was 85:15:3:1.5.

[0121] The prepared mixture was coated on an aluminum foil current collector and then vacuum-dried at 45°C to prepare a negative electrode including a 160 μm thick negative electrode coating layer and a 10 μm thick current collector. The thickness of the negative electrode coating layer was 12 μm.

[0122] (4) Manufacturing of all-solid-state perfect batteries

[0123] The manufactured cathode, solid electrolyte, and counter electrode were sequentially stacked on top of each other, and a pressure of 500 MPa was applied to manufacture a complete battery.

[0124] 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 with formed home; Metal filled inside the above home; and A carbon layer positioned on one side of the current collector to cover the above groove. A cathode for an all-solid-state battery comprising:

2. In paragraph 1, An anode for an all-solid-state battery, wherein the metal is positioned in a groove so as to be lower than the height of the groove in the thickness direction of the current collector.

3. In paragraph 1, An all-solid-state battery negative electrode, wherein the metal is filled in the groove of the current collector and positioned on the surface of the current collector.

4. In paragraph 1, An all-solid-state battery negative electrode, wherein the metal is filled in a groove of the current collector so as to be positioned higher than the height of the groove in the thickness direction of the current collector.

5. In paragraph 1, An all-solid-state battery negative electrode, wherein the metal is located on the lower surface and the peripheral surface of the groove and on the surface of the current collector.

6. In paragraph 1, The above metal is Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd or a combination thereof, and is a negative electrode for an all-solid-state battery.

7. In paragraph 1, The above metal is Ag, an all-solid-state battery negative electrode.

8. In paragraph 1, An all-solid-state battery negative electrode having a diameter of the above groove of 200㎛ or less.

9. In paragraph 1, An anode for an all-solid-state battery, wherein the thickness of the above-mentioned groove is 90% or less with respect to 100% of the thickness of the above-mentioned current collector.

10. In paragraph 1, An all-solid-state battery negative electrode, wherein the metal is filled inside the groove to an area of ​​50% or less with respect to 100% of the inside area of ​​the groove.

11. In paragraph 1, An all-solid-state battery negative electrode, wherein the carbon layer comprises amorphous carbon.

12. The cathode of any one of clauses 1 to 11; Bipolar; and A solid electrolyte layer positioned between the cathode and the anode An all-solid-state battery comprising:

13. In paragraph 12, The above solid electrolyte is an all-solid-state battery which is a sulfide-based solid electrolyte.

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