A negative electrode for all-solid-state batteries and all-solid-state batteries containing the same

Abstract

The present invention relates to a negative electrode for a solid-state battery and a solid-state battery containing the same, wherein the negative electrode for the solid-state battery includes a current collector and a negative electrode coating layer located on the current collector, the negative electrode coating layer includes a first region adjacent to the current collector and a second region not adjacent to the current collector, the first region and the second region each contain MX (where M is a metal reactable with lithium and X is a halogen or nitride), M, and amorphous carbon, the MX content in the first region is greater than the MX content in the second region.

Description

[Technical Field]

[0001] This relates to a negative electrode for all-solid-state batteries and all-solid-state batteries containing the same. [Background technology]

[0002] Recently, with the rapid proliferation of electronic devices that use batteries, such as mobile phones, laptops, and electric vehicles, the demand for small, lightweight, yet relatively high-capacity rechargeable batteries has been rapidly increasing. In particular, lithium-ion batteries are attracting attention as a power source for portable devices due to their light weight and high energy density. As a result, research and development to improve the performance of lithium-ion batteries is being actively pursued.

[0003] Among lithium-ion secondary batteries, all-solid-state batteries are batteries in which all materials are solid, and in particular, batteries that use a solid electrolyte. [Overview of the project] [Problems that the invention aims to solve]

[0004] One embodiment provides a negative electrode for an all-solid-state battery that exhibits excellent battery chemical properties.

[0005] Another embodiment provides an all-solid-state battery including the negative electrode. [Means for solving the problem]

[0006] One embodiment provides a negative electrode for an all-solid-state battery, comprising a current collector; and a negative electrode coating layer located on the current collector, wherein the negative electrode coating layer comprises a first region adjacent to the current collector and a second region not adjacent to the current collector, and the first region and the second region comprise MX(M is a metal reactable with lithium, X is a halogen or nitride, M and amorphous carbon, and the MX content in the first region is greater than the MX content in the second region).

[0007] Another embodiment provides an all-solid-state battery comprising a negative electrode; a positive electrode; and a solid electrolyte layer located between the negative electrode and the positive electrode. [Effects of the Invention]

[0008] A negative electrode for an all-solid-state battery according to one embodiment can exhibit excellent electrochemical properties. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the negative electrode of an all-solid-state battery according to one embodiment. [Figure 2] This is a schematic diagram illustrating an all-solid-state battery according to another embodiment. [Figure 3] This is a schematic diagram illustrating another embodiment of an all-solid-state battery. [Modes for carrying out the invention]

[0010] The embodiments of the present invention will be described in detail below. However, these are presented as examples only and do not limit the present invention, which is defined solely by the claims described below.

[0011] The terms used herein are for illustrative purposes only and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0012] Here, "these combinations" refers to mixtures of components, laminates, composites, copolymers, alloys, blends, reaction products, etc.

[0013] Here, terms such as “includes,” “possess,” or “have” are intended to specify the existence of the implemented features, figures, stages, components, or combinations thereof, and should be understood not to preemptively exclude the possibility of the existence or addition of one or more other features, figures, stages, components, or combinations thereof.

[0014] In the drawings, thicknesses are shown enlarged to clearly represent various layers and regions, and similar parts are given the same reference numerals throughout the specification. When a layer, film, region, plate, or other part is described as being "on top of" another part, this includes not only when it is "directly on top" of the other part, but also when there is another part in between. Conversely, when one part is described as being "directly on top of" another part, it means that there is no other part in between.

[0015] Furthermore, the term "layer" here includes not only the shapes formed on the entire surface when observed in a plan view, but also the shapes formed on some of the surfaces.

[0016] Here, "or" is not interpreted as having an exclusive meaning; for example, "A or B" is interpreted as including A, B, A+B, etc.

[0017] Unless otherwise defined herein, particle size or size may refer to average particle size. This average particle size refers to the average particle size (D50), which means the diameter of the particle whose cumulative volume in the particle size distribution is 50% by volume. The average particle size (D50) can be measured by methods well known to those skilled in the art, such as by a particle size analyzer, or by photographs taken with a transmission electron microscope or scanning electron microscope. Alternatively, it can be measured using a dynamic light-scattering device, and after data analysis to count the number of particles for each particle size range, the average particle size (D50) value can be calculated.

[0018] A negative electrode for an all-solid-state battery according to one embodiment includes a current collector and a negative electrode coating layer located on the current collector. The negative electrode coating layer includes amorphous carbon, metal, and MX.

[0019] In one embodiment, the negative electrode coating layer refers to a layer that plays a role in facilitating the migration of lithium ions released from the positive electrode active material during charging and discharging of an all-solid-state battery to the negative electrode side, thereby promoting deposition on the surface of the current collector. That is, a lithium-containing layer is formed between the current collector and the negative electrode coating layer by the deposition of lithium ions, and this lithium-containing layer acts as the negative electrode active material. Such a negative electrode is generally called a deposition-type negative electrode.

[0020] The negative electrode coating layer includes a first region adjacent to the current collector and a second region not adjacent to the current collector. In this case, the first region and the second region contain MX (where M is a metal that can react with lithium, and X is a halogen or nitride), M, and amorphous carbon, and the MX content in the first region may be greater than the MX content in the second region.

[0021] In one embodiment, M may be a metal that reacts with lithium, such as Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof. In another embodiment, M may be Ag.

[0022] Furthermore, X may be a halogen or a nitride. The halogen may be F, Cl, Br, I, or a combination thereof, or F, Cl, or a combination thereof. In the case of a nitride, X may be NO3, NO2, N, or a combination thereof.

[0023] For example, if M is Ag and X is F, then MX means AgF. Also, if M is Ag and X is a nitride, then MX means AgNO3, AgNO2, or Ag3N.

[0024] In one embodiment, a negative electrode coating layer including a first region adjacent to the current collector and a second region not adjacent to the current collector will be described with reference to Figure 1. As shown in Figure 1, the negative electrode coating layer constituting the negative electrode 1 may exist in two regions, with the first region 5 located adjacent to the current collector 3 and the second region 7 located on the surface of the negative electrode 1 without being adjacent to the current collector 3.

[0025] Since the second region is located on the surface of the negative electrode, this second region in the all-solid-state battery including the negative electrode can be in contact with the solid electrolyte layer.

[0026] In one embodiment, the negative electrode coating layer exists in two regions, and the MX may be entirely contained in the first and second regions, in which case the MX content in the first region may be greater than the MX content in the second region.

[0027] In one embodiment, when MX is included in the negative electrode coating layer, for example, in the negative electrode coating layer of a deposition-type negative electrode, and especially when it is present in excess in the first region compared to the second region, lithium can be uniformly laminated when a lithium-containing layer is formed on the current collector, and lithium dendrite formation can be effectively suppressed. Furthermore, MX can also play a role as a negative electrode active material.

[0028] Furthermore, since the MX is excessively located in the first region that contacts the current collector compared to the second region that does not contact the current collector, the volume change that can be caused by the reaction of MX with lithium ions is likely to occur mainly on the current collector side. Consequently, since almost no shear strength due to the volume change is applied to the solid electrolyte layer, the phenomenon of cracking of the solid electrolyte layer can be suppressed, and the occurrence of short circuits can be suppressed, thereby improving the long-life characteristics.

[0029] If MX is present in excess in the second region compared to the first region, the shear strength due to volume expansion is mainly transmitted to the solid electrolyte layer in contact with the second region. This can cause a short circuit to occur due to the cracking of the solid electrolyte layer.

[0030] In one embodiment, the MX content in the first region may be 2% to 80% by weight, 5% to 75% by weight, or 7% to 70% by weight, based on 100% by weight of the entire first region.

[0031] The MX content in the second region may be 1% to 50% by weight, 2% to 50% by weight, 2% to 40% by weight, or 3% to 30% by weight, based on 100% by weight of the entire second region.

[0032] In one embodiment, the ratio of the MX content in the first region to the MX content in the second region may be 1.2:1 to 10:1, 1.4:1 to 9:1, or 3:1 to 9:1.

[0033] When the MX content in the first and second regions falls within the aforementioned range, lithium can be more uniformly layered on the current collector without additional reaction with lithium during charging, and lithium dendrite formation can be more effectively suppressed.

[0034] Furthermore, the total MX content in the negative electrode coating layer according to one embodiment (i.e., the total MX content in the first and second regions) may be 5% to 70% by weight, or 5% to 60% by weight, relative to 100% by weight of the total negative electrode coating layer. When the total MX content falls within the aforementioned range, lithium can be laminated more uniformly on the current collector, and lithium dendrite formation can be suppressed more effectively.

[0035] In one embodiment, M may be entirely contained within the first and second regions. M may be the same as MX.

[0036] In one embodiment, the content of M in the first region may be the same as, or different from, the content of M in the second region.

[0037] In one embodiment, the content of M in the first region may be 1% to 45% by weight, 1% to 30% by weight, 1% to 20% by weight, 1% to 15% by weight, or 1% to 10% by weight, based on 100% by weight of the entire first region.

[0038] The content of M in the second region may be 1% to 45% by weight, 1% to 30% by weight, 1% to 20% by weight, 1% to 15% by weight, or 1% to 10% by weight, based on 100% by weight of the entire second region.

[0039] The aforementioned M may be nanoparticles, and the size of the nanoparticles may, for example, have an average size of 5 nm to 80 nm, but any nanometer size can be used as appropriate.

[0040] In one embodiment, the thickness of the first region may be 20% or more and less than 80%, 20% or more and 50%, or 20% or more and 40% or less, relative to the total thickness of the negative electrode coating layer (100%). The thickness of the second region is the negative electrode coating layer minus the thickness of the first region.

[0041] In one embodiment, the amorphous carbon may be entirely contained within the first and second regions. Therefore, the amorphous carbon in the negative electrode coating layer according to one embodiment can be located throughout.

[0042] The amorphous carbon may be carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, or a combination thereof. An example of the carbon black is Super P (Timcal). The amorphous carbon may be carbon black, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0043] Furthermore, the amorphous carbon may be 20% to 99% by weight, 40% to 90% by weight, or 50% to 85% by weight, relative to 100% by weight of the total weight of the negative electrode coating layer. The respective amorphous carbon content in the first region and the second region may be the same or different, and there is no need to limit the amorphous carbon content in each region, i.e., in the first region and the second region. For example, if the amorphous carbon content is 20% by weight relative to 100% by weight of the total weight of the negative electrode coating layer, then 10% by weight may be included in the first region (20% by weight relative to the total 100% by weight of the first region) and 10% by weight may be included in the second region (20% by weight relative to the total 100% by weight of the second region).

[0044] The amorphous carbon may be a single particle or an assembly having a secondary particle form in which primary particles are assembled. When the amorphous carbon is a single particle, it may be amorphous carbon particles having an average particle size of 100 nm or less, for example, nano-sized amorphous carbon particles of 10 nm to 100 nm.

[0045] Furthermore, 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.

[0046] In one embodiment, the particle size of the primary particles may be 20 nm to 90 nm, 30 nm to 90 nm, or 30 nm to 80 nm.

[0047] In one embodiment, the particle size of the secondary particles may be 2 μm to 15 μm, 3 μm to 15 μm, or 3 μm to 10 μm.

[0048] The morphology of the primary particles can be spherical, elliptical, plate-like, or a combination thereof, and in one embodiment, the morphology of the primary particles can be spherical, elliptical, or a combination thereof.

[0049] The negative electrode coating layer may further contain a binder. If the negative electrode coating layer consists of a first region and a second region, the binder contained in the first region and the second region may be the same.

[0050] The binder may include a non-aqueous binder, an aqueous binder, or a combination thereof.

[0051] 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, polyamide-imide, polyimide, polyacrylate, or combinations thereof.

[0052] Examples of the aqueous binder include rubber-based binders and polymer resin binders. The rubber-based binder may be selected from styrene-butadiene rubber, acrylate-based styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0053] When an aqueous binder is used as the negative electrode binder, it may contain a cellulose-based compound. For example, a cellulose-based compound can be used together with the aqueous binder.

[0054] The cellulosic compound may include carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, alkali metal salts thereof, or combinations thereof. Na, K, or Li can be used as the alkali metal. The cellulosic compound can function as both a binder and a thickening agent that imparts viscosity. Therefore, there is no particular limit to the content of the cellulosic compound, but for example, it may be 0.1 to 3 parts by weight per 100 parts by weight of the negative electrode active material.

[0055] The aforementioned binders are not limited to these, and any binder used in the art is acceptable, and their content can be adjusted as appropriate.

[0056] The binder may be present in an amount of 1% to 15% by weight relative to 100% by weight of the entire negative electrode coating layer. For example, the binder may be present in an amount of 2% to 12% by weight, 2% to 10% by weight, or 2% to 8% by weight relative to 100% by weight of the entire negative electrode coating layer. The binder content in the first region and the second region may be the same or different, and there is no need to limit the binder content in each region, i.e., in the first region and the second region. For example, if the binder content is 10% by weight relative to 100% by weight of the entire negative electrode coating layer, 5% by weight may be present in the first region and 5% by weight in the second region.

[0057] When the binder is included in the negative electrode coating layer of the all-solid-state battery within the aforementioned content range, electrical resistance and adhesion are improved, and the characteristics of the all-solid-state battery (battery capacity and output characteristics) can be enhanced.

[0058] The negative electrode coating layer may further contain additives such as fillers, dispersants, and ion conductive materials. Known materials commonly used in all-solid-state batteries can be used as fillers, dispersants, and ion conductive materials that can be included in the negative electrode coating layer.

[0059] In one embodiment, the negative electrode may further include a lithium-containing layer between the current collector and the negative electrode catalyst layer.

[0060] Since the lithium-containing layer is a metallic layer containing lithium, it can function, for example, as a lithium reservoir.

[0061] The lithium-containing layer may be a lithium-deposited layer formed when lithium ions released from the positive electrode active material during charging move to the negative electrode side and are deposited on the surface of the current collector. In this case, the lithium-containing layer can be referred to as a lithium-deposited layer.

[0062] The lithium-containing layer may be a layer containing lithium or a lithium alloy.

[0063] The lithium alloy may contain lithium and may also contain metals alloyable with lithium. The metals alloyable with lithium may be Ag, Au, Mg, In, Si, Sn, Al, Ge, Pb, Bi, SbSi-Y alloy (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and not Si), Sn-Y alloy (where Y is an alkali metal, alkaline earth metal, group 13 element, group 14 element, transition metal, rare earth element, or a combination thereof, and not Sn), etc. The 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.

[0064] The thickness of the lithium-containing layer may be 1 μm to 1000 μm, and may be 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 falls within the aforementioned range, it can appropriately function as a lithium storage facility, which may have the advantage of further improving the lifespan.

[0065] If the lithium-containing layer is a lithium deposition layer, this lithium deposition layer can be formed after the manufacture of the all-solid-state battery when lithium ions are released from the positive electrode active material during charging, pass through the solid electrolyte, and move to the negative electrode side, resulting in lithium being deposited and vapor-deposited onto the negative electrode current collector.

[0066] The charging process may be a chemical conversion process carried out one to three times at approximately 25°C to 50°C and 0.05C to 1C. During discharge, the lithium contained in the lithium-containing layer is ionized and moves toward the positive electrode, so this lithium can be used as the negative electrode active material.

[0067] In one embodiment, since the lithium-containing layer is located between the current collector and the negative electrode coating layer, the negative electrode coating layer can act as a protective layer for the lithium-containing layer, thereby suppressing the deposition and growth of lithium dendrites. This suppresses short circuits and capacity degradation in the all-solid-state battery, and consequently improves the cycle life of the all-solid-state battery.

[0068] 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 alloys thereof, and may be in foil or sheet form. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0069] The current collector may further include a thin film formed on a metal substrate. The thin film may contain an element capable of forming an alloy with lithium, such as, but not limited to, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, or a combination thereof, as long as it is an element capable of forming an alloy with lithium in the art. If the current collector further includes a thin film, and the lithium-containing layer is deposited and formed during charging, a more planar lithium-containing layer can be formed, further improving the cycle life of the all-solid-state battery.

[0070] The thickness of the thin film can be between 1 nm and 800 nm, and may be between 10 nm and 700 nm, 50 nm and 600 nm, or 100 nm and 500 nm. When the thin film thickness falls within the aforementioned range, the cycle lifetime characteristics can be further improved.

[0071] The negative electrode according to this embodiment can be formed by applying and drying a negative electrode coating layer composition to a current collector. The negative electrode coating layer composition may include MX, M, amorphous carbon, and a solvent. The MX and amorphous carbon are as described above. The solvent may be water or N-methylpyrrolidone. The drying step can be carried out at 50°C to 100°C and may also be carried out under vacuum conditions.

[0072] When forming the negative electrode coating layer in the first and second regions, it can also be formed in a manufacturing process that is performed two or more times.

[0073] When charging and discharging is performed on an all-solid-state battery containing such a negative electrode, the MX contained in the negative electrode coating layer reacts with lithium that has migrated from the positive electrode to form Li-X, resulting in the presence of Li-X in the negative electrode coating layer.

[0074] Another embodiment provides an all-solid-state battery comprising the negative electrode, the positive electrode, and a solid electrolyte layer located between the negative electrode and the positive electrode.

[0075] The solid electrolyte contained in the solid electrolyte layer can be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte, or a solid polymer electrolyte.

[0076] In one embodiment, the sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m and n are each an integer of 0 or more and 12 or less, Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are each an integer of 0 or more and 12 or less, M is one of P, Si, Ge, B, Al, GaIn), Li a M b P c S d A e (a, b, c, d, and e are each an integer of 0 or more and 12 or less, M is Ge, Sn, Si, or a combination thereof, 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). Specifically, it can be Li3PS4, Li7P3S 11, Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 Li 6.2 PS 5.2 Br 0.8 These are some possibilities.

[0077] As an example, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be, for example, LiaMbPcSdAe (where a, b, c, d, and e are all between 0 and 12, M is Ge, Sn, Si, or a combination thereof, and A is one of F, Cl, Br, or I), specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li6PS5I, Li 5.8 PS 4.8 Cl 1.2 Li 6.2 PS 5.2 Br 0.8 These are some possibilities.

[0078] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixture thereof. For example, the sulfide-based solid electrolyte may be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within the aforementioned mixing ratio range, a sulfide-based solid electrolyte with excellent ionic conductivity can be produced. Further ionic conductivity can be improved by adding other components such as SiS2, GeS2, and B2S3. Mixing methods include mechanical milling and solution methods. Mechanical milling involves placing the starting materials in a reactor and vigorously stirring them with a ball mill or similar device to atomize and mix the starting materials. When using the solution method, the starting materials are mixed in a solvent to obtain the solid electrolyte as a precipitate. Additional calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte may become even harder.

[0079] Of course, a sulfide-based solid electrolyte can also use a commercially available solid electrolyte.

[0080] The 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, P b (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 - GeO2 - based ceramics, garnet - based ceramics Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10), or a mixture thereof can be included.

[0081] The solid polymer electrolyte is, for example, polyethylene oxide, poly(diallyldimethylammonium) trifluoromethanesulfonylimide (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, etc.) 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 is Al or Ga), Li6BaLa2Ta2O 12 、Li7La3Zr2O 12 、Li5La3Nb2O 12 、Li5La3M2O 12 (M is Nb, Ta) and Li 7+xA x La 3-x Zr2O 12 It can contain one or more selected from among (0 < x < 3, where A is Zn).

[0082] The halide-based solid electrolyte can contain a Li element, an M element (M is a metal other than Li), and an X element (X is a halogen). Examples of X include F, Cl, Br, and I. In particular, for the halide-based solid electrolyte, at least one of Br and Cl is suitable as the X. Also, examples of the M include metal elements such as Sc, Y, B, Al, Ga, and In.

[0083] The composition of the halide-based solid electrolyte is not particularly limited, but Li 6-3a MaBr b Cl c (where M in the formula is a metal other than Li, 0 < a < 2, 0 ≤ b ≤ 6, 0 ≤ c ≤ 6, and b + c = 6). At that time, the a can be 0.75 or more, can be 1 or more, and a can be 1.5 or less. The b can be 1 or more, can be 2 or more. Also, the c can be 3 or more, can be 4 or more. Specific examples of the halide-based solid electrolyte include Li3YBr6, Li3YCl6, or Li3YBr2Cl4.

[0084] The solid electrolyte is in particle form, and the average particle size (D50) can 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.

[0085] The solid electrolyte layer may further contain a binder. In this case, the binder may be, but is not limited to, styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, acrylate polymers, or combinations thereof, and any binder used in the art may be used. The acrylate polymer may be butyl acrylate, polyacrylate, polymethacrylate, or combinations thereof.

[0086] The solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating a substrate film with the solution, and drying it. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The process for forming the solid electrolyte layer is well known in the art and therefore will not be described in detail herein.

[0087] The positive electrode includes a current collector and a positive electrode active material layer located on one surface of the current collector. The positive electrode active material layer may contain a positive electrode active material. The positive electrode active material may be a lithiumated compound or a sulfur-based compound that can reversibly intercept and release lithium ions.

[0088] The lithiatide compound can be, for example, one or more composite oxides of a metal selected from cobalt, manganese, nickel, and combinations thereof with lithium. A specific example of a lithiatide compound is Li a A 1-b B 1 b D 12 (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 E2-b B 1 b O 4-c D 1 c (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5);Li a Ni 1-b-c Co b B 1 c D 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α≦2);Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2(0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α≦2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2(0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni b HAVE BEEN c G dO2(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 GeO2(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);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) Examples include Fe2(PO4)3 (0≦f≦2) or LiFePO4.

[0089] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 These are Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or combinations 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 J is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof; L 1 This is Mn, Al, or a combination of these.

[0090] According to one embodiment, as the positive electrode active material, LiNi x Co y Al z O2 (NCA), LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1), etc., ternary lithium transition metal oxides can be mentioned.

[0091] Of course, those having a coating layer on the surface of this compound can also be used, or the compound and a compound having a coating layer can be mixed and used. This coating layer can contain at least one coating element compound selected from the group consisting of oxides of coating elements, hydroxides of coating elements, oxyhydroxides of coating elements, oxycarbonates of coating elements, and hydroxycarbonates of coating elements. The compounds constituting these coating layers can be amorphous or crystalline. As the coating elements contained in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof can be used. The coating layer formation process can use any coating method as long as such elements can be used to coat the compound in a manner that does not adversely affect the physical properties of the positive electrode active material (for example, spray coating, dipping method, etc.). Since this is well understood by those skilled in the art, detailed description is omitted.

[0092] In addition, as the coating layer, any known coating layer for the positive electrode active material of an all-solid-state battery can be applied, and examples thereof include Li2O-ZrO2 (LZO).

[0093] Furthermore, when the positive electrode active material contains nickel, cobalt, and manganese, or nickel, cobalt, and aluminum, the capacity density of the all-solid-state battery can be further improved, and the metal leaching of the positive electrode active material in the charged state can be further reduced. This allows the all-solid-state battery to further improve its long-term reliability and cycle characteristics in the charged state.

[0094] The aforementioned sulfur-based compound is composed of elemental sulfur (S8), solid Li2Sn (n≦1), and Li2S n (n≦1) dissolved catholite, organosulfur compounds, carbon-sulfur polymer [(C2S x ) n x = 2.5 to 50, n ≤ 2, or a combination of these.

[0095] Here, the shape of the positive electrode active material can be, for example, spherical or ellipsoidal particle shapes. Furthermore, the average particle size of the positive electrode active material is not particularly limited and should be within a range applicable to the positive electrode active material of existing all-solid-state secondary batteries. Similarly, the content of the positive electrode active material in the positive electrode active material layer is not particularly limited and should be within a range applicable to the positive electrode layer of existing all-solid-state secondary batteries.

[0096] The positive electrode active material layer may additionally contain a solid electrolyte. The solid electrolyte contained in the positive electrode active material layer may be the same as or different from the solid electrolyte contained in the solid electrolyte layer. The solid electrolyte may be contained in an amount of 10% to 30% by weight based on the total weight of the positive electrode active material layer.

[0097] The 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 alloys thereof, and may be in the form of foil or sheet.

[0098] The positive electrode active material layer may further include a binder and / or a conductive material.

[0099] Examples of the aforementioned binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylate-based styrene-butadiene rubber, epoxy resin, and nylon.

[0100] The binder may be present in an amount of 0.1% to 5% by weight, or 0.1% to 3% by weight, relative to the total weight of each component of the positive electrode for the all-solid-state battery, or relative to the total weight of the positive electrode active material layer. Within the aforementioned content range, the binder can exhibit sufficient adhesive ability without degrading battery performance.

[0101] The aforementioned conductive material is used to impart conductivity to electrodes, and any electronically conductive material that does not cause a chemical change in the battery it is constructed from can be used. Examples include conductive materials containing carbon-based substances such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, and carbon nanotubes, metallic substances in the form of metal powder or metal fibers, conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0102] The conductive material may be present in an amount of 0.1% to 5% by weight, or 0.1% to 3% by weight, relative to the total weight of each component of the positive electrode for the all-solid-state battery, or relative to the total weight of the positive electrode active material layer. Conductive materials within the aforementioned content ranges can improve electrical conductivity without degrading battery performance.

[0103] 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, 100 μm to 190 μm, 120 μm to 180 μm, or 130 μm to 180 μm or less. As mentioned above, since the thickness of the positive electrode active material layer is greater than the thickness of the negative electrode active material layer, the capacitance of the positive electrode is greater than the capacitance of the negative electrode.

[0104] The positive electrode can be manufactured by forming a positive electrode active material layer on a positive electrode current collector using a dry or wet coating method.

[0105] In one embodiment, the all-solid-state battery may include additional buffering material to mitigate the thickness changes that occur during charging and discharging. The buffering material may be located between the negative electrode and the case, and in the case of a battery in which one or more electrode assemblies are stacked, it may be located between different electrode assemblies.

[0106] Examples of the cushioning material include substances with an elastic recovery rate of 50% or more and insulating properties, specifically, silicone rubber, acrylic rubber, fluororubber, nylon, synthetic rubber, or combinations thereof. The cushioning material may exist in the form of a polymer sheet.

[0107] Figure 2 is a cross-sectional view of an all-solid-state battery according to one embodiment. Referring to Figure 2, the all-solid-state battery 100 may have a structure in which an electrode assembly is housed in a case such as a pouch, with the negative electrode 400 including a negative electrode current 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 current collector 201, all of which are stacked. The all-solid-state battery 100 may further include an elastic layer 500 on the outside of at least one of the positive electrode 200 and the negative electrode 400. Figure 2 shows one electrode assembly including a negative electrode 400, a solid electrolyte layer 300, and a positive electrode 200, but an all-solid-state battery can also be made by stacking two or more electrode assemblies.

[0108] Figure 3 schematically shows the structure of a fully charged all-solid-state battery. The all-solid-state battery 100 includes a positive electrode 200 containing a positive electrode current collector 201 and a positive electrode active material layer 203, a negative electrode 400' containing a negative electrode current collector 401' and a negative electrode coating layer 403', and a solid electrolyte layer 300 located between the positive electrode 200 and the negative electrode 400', and includes a battery case 500 in which these are housed.

[0109] Furthermore, lithium ions are released from the positive electrode active material and deposited onto the negative electrode current collector 401', resulting in the lithium-containing layer 405' being located between the current collector 401' and the negative electrode coating layer 403'.

[0110] An all-solid-state battery according to one embodiment can be manufactured by preparing a laminate by positioning a negative electrode, a positive electrode, and a solid electrolyte layer between the negative and positive electrodes, and then pressing this laminate.

[0111] The pressurization process can be carried out in a temperature range of 25°C to 90°C. Furthermore, the pressurization process can be carried out by applying pressure of 550 MPa or less, for example, 500 MPa or less, for example, in the range of 1 MPa to 500 MPa. The pressurization time may vary depending on the temperature and pressure, and may be, for example, less than 30 minutes. The pressurization process may be, for example, isostatic press, warm isostatic press, roll press, or plate press. [Modes for carrying out the invention]

[0112] Examples and comparative examples of the present invention are described below. These examples are merely one embodiment of the present invention, and the present invention is not limited to these examples.

[0113] (Example 1) (1) Manufacturing of the negative electrode A first slurry for the negative electrode coating layer was prepared by mixing 81% by weight of carbon black, 2% by weight of Ag (average particle size: 60 nm), 7% by weight of AgF, and 10% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0114] A second slurry for the negative electrode coating layer was prepared by mixing 85% by weight of carbon black, 2% by weight of Ag (average particle size: 60 nm), 3% by weight of AgF, and 10% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0115] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 5 μm thickness and a second region of 5 μm thickness.

[0116] (2) Manufacturing of the solid electrolyte layer An isobutylyl isobutylate binder solution (solid content: 50% by weight), to which butyl acrylate polymers were added, was mixed with an azirodite-type solid electrolyte, Li6PS5Cl. The mixing ratio of the solid electrolyte to the binder was 98.7:1.3 by weight.

[0117] The aforementioned mixing process was carried out using a Thinky mixer. A 2 mm zirconia ball was added to the resulting mixture and stirred again in the Thinky mixer to produce a slurry. The slurry was cast onto a release polytetrafluoroethylene film and dried at room temperature to produce a solid electrolyte with a solid electrolyte layer thickness of 100 μm.

[0118] (3) Manufacturing of all-solid-state batteries The manufactured negative electrode, solid electrolyte, and lithium metal counter electrode were sequentially stacked, and an all-solid-state half-cell was manufactured using a warm isostatic press process, applying a pressure of 500 MPa at 25°C.

[0119] (Example 2) A first slurry for the negative electrode coating layer was prepared by mixing 73 wt% carbon black, 5 wt% Ag (average particle size: 60 nm), 15 wt% AgF, and 7 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0120] A second slurry for the negative electrode coating layer was prepared by mixing 83 wt% carbon black, 5 wt% Ag (average particle size: 60 nm), 5 wt% AgF, and 7 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0121] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 5 μm thickness and a second region of 5 μm thickness.

[0122] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0123] (Example 3) A first slurry for the negative electrode coating layer was prepared by mixing 43 wt% carbon black, 4 wt% Ag (average particle size: 60 nm), 48 wt% AgF, and 5 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0124] A second slurry for the negative electrode coating layer was prepared by mixing 80 wt% carbon black, 4 wt% Ag (average particle size: 60 nm), 6 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0125] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region with a thickness of 3 μm and a second region with a thickness of 6 μm.

[0126] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0127] (Example 4) A first slurry for the negative electrode coating layer was prepared by mixing 30% by weight of carbon black, 5% by weight of Ag (average particle size: 60 nm), 60% by weight of AgF, and 5% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0128] A second slurry for the negative electrode coating layer was prepared by mixing 75% by weight of carbon black, 5% by weight of Ag (average particle size: 60 nm), 15% by weight of AgF, and 5% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0129] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region with a thickness of 3 μm and a second region with a thickness of 6 μm.

[0130] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0131] (Example 5) A first slurry for the negative electrode coating layer was prepared by mixing 18 wt% carbon black, 2 wt% Ag (average particle size: 60 nm), 75 wt% AgF, and 5 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0132] A second slurry for the negative electrode coating layer was prepared by mixing 68 wt% carbon black, 2 wt% Ag (average particle size: 60 nm), 2 wt% AgF, and 5 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0133] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 4 μm thickness and a second region of 4 μm thickness.

[0134] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0135] (Example 6) A first slurry for the negative electrode coating layer was prepared by mixing 25% by weight of carbon black, 2% by weight of Ag (average particle size: 60 nm), 70% by weight of AgF, and 3% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0136] A second slurry for the negative electrode coating layer was prepared by mixing 45% by weight of carbon black, 2% by weight of Ag (average particle size: 60 nm), 50% by weight of AgF, and 3% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0137] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 4 μm thickness and a second region of 4 μm thickness.

[0138] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0139] (Comparative Example 1) A first slurry for the negative electrode coating layer was prepared by mixing 86 wt% carbon black, 3 wt% Ag (average particle size: 60 nm), 1 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0140] A second slurry for the negative electrode coating layer was prepared by mixing 87 wt% carbon black, 3 wt% Ag (average particle size: 60 nm), 0 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0141] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region with a thickness of 3 μm and a second region with a thickness of 7 μm.

[0142] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0143] (Comparative Example 2) A first slurry for the negative electrode coating layer was prepared by mixing 87 wt% carbon black, 3 wt% Ag (average particle size: 60 nm), 0 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0144] A second slurry for the negative electrode coating layer was prepared by mixing 86 wt% carbon black, 3 wt% Ag (average particle size: 60 nm), 1 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0145] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region with a thickness of 3 μm and a second region with a thickness of 7 μm.

[0146] An all-solid-state semi-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer produced from Example 1, and the lithium metal counter electrode.

[0147] (Comparative Example 3) A first slurry for the negative electrode coating layer was prepared by mixing 82 wt% carbon black, 3 wt% Ag (average particle size: 60 nm), 5 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0148] A second slurry for the negative electrode coating layer was prepared by mixing 82% by weight of carbon black, 3% by weight of Ag (average particle size: 60 nm), 5% by weight of AgF, and 10% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0149] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region with a thickness of 3 μm and a second region with a thickness of 7 μm.

[0150] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0151] (Comparative Example 4) (1) Manufacturing of the negative electrode A first slurry for the negative electrode coating layer was prepared by mixing 85 wt% carbon black, 2 wt% Ag (average particle size: 60 nm), 3 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0152] A second slurry for the negative electrode coating layer was prepared by mixing 81% by weight of carbon black, 2% by weight of Ag (average particle size: 60 nm), 7% by weight of AgF, and 10% by weight of polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0153] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 5 μm thickness and a second region of 5 μm thickness.

[0154] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0155] (Comparative Example 5) (1) Manufacturing of the negative electrode A first slurry for the negative electrode coating layer was prepared by mixing 63 wt% carbon black, 2 wt% Ag (average particle size: 60 nm), 25 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0156] A second slurry for the negative electrode coating layer was prepared by mixing 28 wt% carbon black, 2 wt% Ag (average particle size: 60 nm), 60 wt% AgF, and 10 wt% polyvinylidene fluoride from among N-methylpyrrolidone (NMP) solvents.

[0157] A negative electrode was manufactured by coating a stainless steel foil current collector with the first negative electrode coating layer slurry, vacuum drying it at 80°C, then coating it with the second negative electrode coating layer slurry, and vacuum drying it at 80°C, thereby producing a negative electrode containing a first region of 5 μm thickness and a second region of 5 μm thickness.

[0158] An all-solid-state half-cell was manufactured using the aforementioned negative electrode, the solid electrolyte layer manufactured from Example 1 described above, and a lithium metal counter electrode.

[0159] Experimental Example 1) Evaluation of Overpotential The all-solid-state half-cells of Examples 1 to 6 and Comparative Examples 1 to 4 were charged once at 0.05C. The voltage was measured from the point where the voltage drop began at OCV (Open circuit voltage, approximately 2.5V) to the point where the inflection point occurred, starting from approximately 0mV. The measured results are shown as overvoltage in Table 1 below.

[0160] Experimental Example 2) Evaluation of Initial Efficiency The all-solid-state half-cells of Examples 1 to 6 and Comparative Examples 1 to 4 described above were subjected to one charge-discharge cycle at 0.05C. The ratio of discharge capacity to charge capacity was calculated (discharge capacity per cycle / charge capacity per cycle), and the results are shown in Table 1 below as the initial efficiency.

[0161] Experimental Example 3) Evaluation of Output Efficiency The all-solid-state half-cells of Examples 1 to 6 and Comparative Examples 1 to 4 described above were subjected to one charge-discharge cycle at 0.1C. The ratio of discharge capacity to charge capacity was calculated (discharge capacity per cycle / charge capacity per cycle), and the results are shown in Table 1 below as the output efficiency.

[0162] [Table 1]

[0163] As shown in Table 1 above, the semi-solid batteries of Examples 1 to 6, in which the AgF content in the first region was greater than the AgF content in the second region, showed excellent overvoltage characteristics, initial efficiency, and output efficiency. On the other hand, in Comparative Examples 1 and 2, in which AgF was contained in only one of the first or second regions, it can be seen that the overvoltage characteristics, initial efficiency, and output efficiency deteriorated. Furthermore, in Comparative Example 3, in which the same amount of AgF was contained in both the first and second regions, and in Comparative Examples 4 and 5, in which AgF was excessively contained in the second region compared to the first region, it can be seen that the output efficiency deteriorated significantly.

[0164] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and these also naturally fall within the scope of the present invention.

Claims

1. Current collector; and, The current collector includes a negative electrode coating layer located on the current collector, The negative electrode coating layer includes a first region adjacent to the current collector and a second region not adjacent to the current collector. The first region and the second region each contain M-X (where M is a metal reactable with lithium, and X is a halogen or nitride), M, and amorphous carbon, wherein the M-X content in the first region is greater than the M-X content in the second region. Negative electrode for all-solid-state batteries.

2. The negative electrode for an all-solid-state battery according to claim 1, wherein M is Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof.

3. The negative electrode for an all-solid-state battery according to claim 1, wherein M is Ag.

4. The above X is F, Cl, Br, I, NO ３ NO ２ A negative electrode for an all-solid-state battery according to claim 1, which is N, or a combination thereof.

5. The aforementioned M-X is AgF, AgNO ３ AgNO ２ Ag ３ A negative electrode for an all-solid-state battery according to claim 1, wherein N, or a combination thereof.

6. The negative electrode for an all-solid-state battery according to claim 1, wherein the content of M-X in the first region is 2% by weight to 80% by weight relative to 100% by weight of the entire first region.

7. The negative electrode for an all-solid-state battery according to claim 1, wherein the content of M-X in the second region is 1% by weight to 50% by weight relative to 100% by weight of the entire second region.

8. The negative electrode for an all-solid-state battery according to claim 1, wherein the ratio of the content of M-X in the first region to the content of M-X in the second region is 1.2:1 to 10:

1.

9. The negative electrode for an all-solid-state battery according to claim 1, wherein the content of M in the first region is 1% by weight to 45% by weight relative to 100% by weight of the entire first region.

10. The negative electrode for an all-solid-state battery according to claim 1, wherein the content of M in the second region is 1% by weight to 45% by weight relative to 100% by weight of the entire second region.

11. The negative electrode for an all-solid-state battery according to claim 1, wherein the thickness of the first region is 20% or more and less than 80% in the thickness direction relative to 100% of the total thickness of the negative electrode coating layer.

12. The negative electrode for an all-solid-state battery according to claim 1, wherein the content of M-X is 5% to 70% by weight relative to 100% by weight of the entire negative electrode coating layer.

13. The negative electrode for an all-solid-state battery according to claim 1, wherein the thickness of the first region is 20% to 50% in the thickness direction relative to the total thickness of the negative electrode coating layer, which is 100%.

14. The amorphous carbon is carbon black, acetylene black, denka black, ketjen black, furnace black, activated carbon, or a combination thereof, as described in claim 1, for a negative electrode for an all-solid-state battery.

15. The negative electrode according to any one of claims 1 to 14; Positive electrode; and, A solid electrolyte layer located between the negative electrode and the positive electrode, All-solid-state batteries, including those mentioned above.

16. The all-solid-state battery according to claim 15, wherein the negative electrode further includes a lithium-containing layer between the current collector and the negative electrode catalyst layer.

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