Negative electrode coating composition for all-solid-state battery, method for producing the same and all-solid-state battery including the same

Abstract

The present invention relates to an anode coating composition for an all-solid-state battery and an all-solid-state battery including the same, wherein the anode coating composition for an all-solid-state battery includes a metal and a carbon-based material, and the metal and the carbon-based material are chemically bonded via sulfur.

Description

[Technical Field]

[0001] The present invention relates to a negative electrode coating composition for an all-solid-state battery and an all-solid-state battery including the same. [Background technology]

[0002] Recently, with the rapid spread of battery-powered electronic devices such as mobile phones, laptops, and electric vehicles, the demand for small, lightweight, and relatively high-capacity secondary batteries has been growing rapidly. In particular, lithium secondary batteries have attracted attention as a power source for portable devices due to their light weight and high energy density. As a result, research and development efforts to improve the performance of lithium secondary batteries have been actively pursued.

[0003] Among lithium secondary batteries, all-solid-state batteries are batteries that are composed entirely of solid materials, particularly those that use a solid electrolyte. One way to increase the energy density of such all-solid-state batteries is to use lithium metal as the anode. However, this method poses problems due to the volume expansion of lithium and irreversible dendrite growth during charging and discharging.

[0004] To solve these problems, a method of constructing an anode without using lithium metal itself, but by forming a layer in which lithium is deposited on the anode current collector during charging and discharging, is being studied. However, this method is not suitable because it results in low output characteristics and excessive short circuiting. Summary of the Invention [Problem to be solved by the invention]

[0005] One embodiment provides an anode coating composition for an all-solid-state battery that has a strong bond between metal and carbon.

[0006] Another embodiment provides an all-solid-state battery comprising the anode coating composition. [Means for solving the problem]

[0007] One embodiment provides a coating composition for an anode of an all-solid-state battery, comprising a metal and a carbon-based material, wherein the metal and the carbon-based material are chemically bonded to each other via sulfur.

[0008] The negative electrode coating composition may have a metal-sulfur bond-related peak in a spectrum obtained from an XPS analysis.

[0009] The negative electrode coating composition may have a peak appearing at a binding energy of 160 eV to 162 eV in an S2p spectrum obtained from an XPS analysis.

[0010] The carbon-based material may be amorphous carbon, crystalline carbon, or a mixture thereof.

[0011] The metal can be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof.

[0012] The content of the metal may be 3 wt % to 40 wt % based on 100 wt % of the total content of the metal and the carbon-based material.

[0013] Another embodiment provides a method for preparing a negative electrode coating composition for an all-solid-state battery, the method comprising the steps of: mixing a carbonaceous material and a sulfur source material to prepare a mixture; loading a metal onto the mixture to prepare a loaded product; and heat-treating the loaded product.

[0014] The sulfur source material may be a thiol compound, a sulfide-based compound, a thiophene-based compound, a sulfonic acid, a sulfone, a sulfoxide, or a combination thereof.

[0015] The heat treatment step can be carried out at a temperature of 100 to 500°C.

[0016] Another embodiment provides an all-solid-state battery comprising: a negative electrode including a current collector and a negative electrode coating layer disposed on one surface of the current collector; a positive electrode; and a solid electrolyte layer disposed between the negative electrode and the positive electrode, wherein the negative electrode coating layer comprises the negative electrode coating composition.

[0017] The solid electrolyte may be a sulfide-based solid electrolyte.

[0018] The all-solid-state battery may further include a lithium-containing layer formed between the current collector and the negative electrode coating layer during initial charging. [Effects of the Invention]

[0019] The coating composition for an anode of an all-solid-state battery according to an embodiment has a strong bonding force between the metal and the carbon, and the metal is uniformly dispersed in the carbon-based material, thereby preventing aggregation of metal particles. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram illustrating an all-solid-state battery according to an embodiment. [Figure 2] FIG. 1 is a schematic cross-sectional view showing an all-solid-state battery according to an embodiment in a state after charging. [Figure 3] 1 is a TEM photograph of the negative electrode coating composition prepared in Example 1. [Figure 4] 1 is a TEM photograph of the negative electrode coating composition prepared in Comparative Example 1. [Figure 5] 1 is a graph showing XPS S2p spectra for anode coating compositions prepared in Example 1, Comparative Example 1, and Comparative Example 2. [Figure 6] 1 is a graph showing weight changes obtained by measuring thermogravimetric analysis of the negative electrode coating compositions of Example 1 and Comparative Example 2. [Figure 7] 1 is a graph showing DTG changes obtained by measuring thermogravimetric analysis of the negative electrode coating compositions of Example 1 and Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail, but these are presented as examples and should not be construed as limiting the present invention, which is defined only by the scope of the claims that follow.

[0022] Unless otherwise specified in this specification, when a layer, film, region, plate, or other part is said to be "on" another part, this includes not only when it is "directly on" the other part, but also when there is another part between them.

[0023] In the present invention, "particle size" or "particle diameter" may refer to an average particle diameter. The average particle diameter may be defined as the average particle diameter (D50) at 50% of the cumulative volume on a particle size distribution curve. The particle diameter may be measured by electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), or the like, or by a laser diffraction method. Specifically, when measuring by the laser diffraction method, particles to be measured are dispersed in a dispersion medium, introduced into a commercially available laser diffraction particle size analyzer (e.g., Microtrac's MT3000), and irradiated with ultrasonic waves of about 28 kHz at an output of 60 W. The average particle diameter (D50) at 50% of the particle size distribution measured by the analyzer can then be calculated.

[0024] One embodiment relates to an anode coating composition for an all-solid-state battery. In one embodiment, the anode coating layer for an all-solid-state battery refers to a material that facilitates the migration of lithium ions released from a cathode active material to the anode during charging and discharging of the all-solid-state battery and the precipitation of the lithium ions on the surface of the current collector. Such an anode coating composition may be included in the anode coating layer of the all-solid-state battery. In addition, an anode of an all-solid-state battery including such an anode coating layer has a lithium deposition layer formed between the current collector and the anode coating layer due to the deposition of lithium ions, and this lithium deposition layer serves as the anode active material. Such an anode is generally referred to as a deposition-type anode.

[0025] According to an embodiment, the coating composition for an anode of an all-solid-state battery includes a metal and a carbon-based material, and the metal and the carbon-based material are chemically bonded to each other via sulfur.

[0026] More specifically, this is not a simple physical mixture or assembly of metal and carbon-based material, but a state in which the metal and carbon-based material are chemically bonded to each other. The chemical bond between the metal and carbon-based material may be a sulfur-mediated chemical bond.

[0027] The chemical bond between the metal and the carbon-based material can be obtained by using a sulfur source material in the process of preparing the anode coating, which will be described in detail below in the process of preparing the anode coating composition.

[0028] Because the metal and the carbon-based material are chemically bonded, the bonding strength is superior to that of a physical bond, which effectively prevents separation of the metal and the carbon-based material during the mixing process when manufacturing an anode using this anode coating composition. Generally, anode coating compositions are in the form of a mixture of a metal and a carbon-based material, and it is difficult to uniformly disperse the metal in the carbon-based material. However, the anode coating composition according to one embodiment allows the metal to be uniformly dispersed in the carbon-based material via the functional groups uniformly distributed therein. This prevents metal aggregation and allows for uniform current distribution within the anode.

[0029] In the anode coating composition according to one embodiment, the metal and the carbon-based material are chemically bonded via sulfur, which can be confirmed as a metal-sulfur (MS) bond-related peak in the spectrum obtained by XPS analysis.

[0030] For example, when the metal is silver, the S2p spectrum obtained from the XPS analysis may have a peak appearing at a binding energy of 160 eV to 162 eV.

[0031] If the metal and carbon-based material are simply mixed, i.e., not chemically bonded via sulfur, such peaks will not appear in XPS analysis. In addition, if a sulfur-containing compound is coated on a carbon-based material but not chemically bonded, two peaks may be observed: one at a binding energy of 160 eV to 162 eV and the other at a binding energy of 163 eV to 166 eV.

[0032] The carbon-based material may be amorphous carbon, crystalline carbon, or a mixture thereof. The amorphous carbon may be, for example, carbon black, acetylene black, denka black, ketjen black, furnace black, activated carbon, or a combination thereof. An example of the carbon black is Super P (Timcal). The crystalline carbon may be natural graphite, artificial graphite, carbon nanotubes, graphene, or a combination thereof. The crystalline carbon may be amorphous, plate-like, flake-like, spherical, or fibrous.

[0033] In one embodiment, the metal may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof. When the negative electrode coating composition contains the metal, the conductivity of the negative electrode can be further improved.

[0034] The metal may be nanoparticles, and the average size of the metal nanoparticles may be, for example, 5 nm to 80 nm, although nanometer-sized nanoparticles are suitable. The use of nanometer-sized metal nanoparticles can improve the battery characteristics (e.g., life characteristics) of all-solid-state batteries. Increasing the metal particle size to the micrometer level is not suitable because it can reduce the uniformity of the metal particles in the anode coating layer, increase the current density in a specific region, and reduce cycle life characteristics.

[0035] In the negative electrode coating composition according to an 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 %, relative to 100 wt % of the total content of the negative electrode coating composition.

[0036] In addition, the carbon-based 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 the total amount (100 wt %) of the negative electrode coating composition.

[0037] Since the metal and the carbon-based material in the anode coating composition are chemically bonded via sulfur, sulfur may be present in the anode coating composition. Since sulfur functions to chemically bond the metal and the carbon-based material, it is not necessarily present independently. The sulfur content is so small that it can be quantitatively analyzed, and therefore, the sulfur content is not limited.

[0038] When the content of the metal or the carbon-based material is within the above range, the metal can be uniformly dispersed in the carbon-based material.Furthermore, when the content of the metal and the carbon-based material is within the above range, a lithium deposition layer formed when lithium ions released from the positive electrode active material migrate to the negative electrode during charging is substantially mostly formed between the current collector and the negative electrode coating layer, thereby effectively preventing short-circuiting problems, side reactions with the electrolyte, or cracks on the negative electrode that may occur when lithium deposition occurs on the surface of the negative electrode coating layer.

[0039] The amorphous carbon may be a single particle or an assembly of primary particles in the form of a secondary particle. When the amorphous carbon is a single particle, the amorphous carbon may be an amorphous carbon particle having an average particle size of 100 nm or less, for example, a nano-size of 10 nm to 100 nm.

[0040] In addition, 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.

[0041] In one embodiment, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and may be 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0042] In one embodiment, the particle size of the secondary particles may be 1 μm or more, 3 μm or more, 5 μm or more, 7 μm or more, 10 μm or more, or 15 μm or more, and may be 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, or 3 μm or less.

[0043] The shape of the primary particles may be spherical, ellipsoidal, plate-like, or a combination thereof. In one embodiment, the shape of the primary particles may be spherical, ellipsoidal, or a combination thereof.

[0044] The negative electrode coating composition according to one embodiment may be prepared by the following preparation process.

[0045] The carbonaceous material is mixed with the sulfur source material. This mixing process can be performed in a dry or wet manner. When the mixing process is performed in a dry manner, the sulfur source material is in a solid state at room temperature. When the mixing process is performed in a wet manner, the sulfur source material is in a liquid state at room temperature.

[0046] The carbon-based material may be amorphous carbon or crystalline carbon as previously described.

[0047] The sulfur source material may be a thiol compound, a sulfide-based compound, a thiophene-based compound, a sulfonic acid, a sulfone, a sulfoxide, or a combination thereof. In one embodiment, the sulfur-containing compound may be a thiol compound.

[0048] The thiol compound may be mercaptoacetic acid, 1-dodecanethiol, 6-mercapto-1-hexanol, 11-mercapto-1-undecanol, 2-naphthalenethiol, 1,4-benzenedimethanethiol, 4-mercaptobenzoic acid, 1,3-benzenedithiol, or a combination thereof. The sulfide compound may be polyphenylene sulfide, carbon disulfide, metal sulfide, or a combination thereof. The metal in the metal sulfide may be Ag, Na, Zn, Fe, or a combination thereof. The thiophene-based compound may be thiophene (C4H4S), 2-methylthiophene, thianaphthalene, 4,6-dimethyldibenzothiophene, or a combination thereof. The sulfonic acid may be p-toluenesulfonic acid, sodium dodecylbenzenesulfonate, taurine, or a combination thereof. The sulfone may be dimethyl sulfone, 4,4'-dichlorodiphenyl sulfone, or a combination thereof. The sulfoxide may be dimethyl sulfoxide, methyl phenyl sulfoxide, or a combination thereof.

[0049] Regardless of whether the mixing process is performed in a dry or wet manner, the carbonaceous material and the sulfur source material may be mixed in a weight ratio of 4:1 to 999:1, which may be 4:1 to 900:1, 5:1 to 100:1, or 5:1 to 20:1.

[0050] The resulting mixture is then heat-treated, and the surface of the carbon-based material may be coated with the sulfur source material through this mixing and heat-treatment process. The heat-treatment process may be performed at 70°C to 110°C.

[0051] A metal is loaded onto the heat-treated product to produce a loaded product. The loading step can be carried out by adding a metal compound and a reducing agent to the mixture. This loading step can be carried out in a solvent, such as water, ethanol, glycerol, benzene, xylene, or a combination thereof. The reducing agent can be NaBH4, ascorbic acid, trisodium citrate, ethylene glycol, or a combination thereof.

[0052] In the metal loading step, the amount of metal compound used can be adjusted to 3 wt% to 40 wt%, 4 wt% to 25 wt%, 5 wt% to 20 wt%, or 5 wt% to 15 wt% based on 100 wt% of the total weight of the carbonaceous material and metal in the loaded product. The amount of reducing agent used is not particularly limited as long as it is in an amount appropriate for causing the reduction reaction of the metal compound. For example, the amount of reducing agent used can be 10 wt% to 300 wt% based on 100 wt% of the metal compound.

[0053] The metal compound may be a metal nitride, a metal sulfate, a metal perchlorate, or a combination thereof, for example, when the metal is Ag, it may be AgNO3, Ag2SO4, AgClO4, or a combination thereof.

[0054] The resulting supported product is heat-treated. The heat-treatment step can be carried out at a temperature at which the sulfur source material can be decomposed and removed, for example, at 100°C to 500°C, 150°C to 500°C, 200°C to 450°C, or 200°C to 400°C. Specifically, when a thiol compound is used as the sulfur source material, the heat treatment can be carried out at 100°C to 400°C.

[0055] The heat treatment can be performed in a nitrogen atmosphere, an argon atmosphere, or a combination thereof for 2 to 20 hours.

[0056] This heat treatment process decomposes the sulfur source material, so that no sulfur source material remains in the final anode coating layer. Since sulfur in the anode coating layer is present in combination with a metal and a carbon-based material, the metal and the carbon-based material may be contained in the anode coating layer in a state of being chemically bonded via sulfur.

[0057] Another embodiment provides an all-solid-state battery comprising the anode coating composition.

[0058] The all-solid-state battery includes an anode including a current collector and an anode coating layer disposed on one surface of the current collector, a cathode, and a solid electrolyte layer disposed between the anode and the cathode, wherein the anode coating layer includes the anode coating composition according to the embodiment.

[0059] The content of the negative electrode coating composition may be 60% by weight to 99% by weight, or 85% by weight to 99% by weight, based on 100% by weight of the total negative electrode coating layer.

[0060] The binder can include a water-insoluble binder, a water-soluble binder, or a combination thereof.

[0061] The water-insoluble binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer containing ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or a combination thereof.

[0062] The water-soluble binder may be a rubber-based binder or a polymer resin binder. 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.

[0063] When a water-soluble binder is used as the negative electrode binder, it may be used together with a thickener that can impart viscosity. The thickener may include, for example, a cellulose-based compound. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, alkali metal salts thereof, or combinations thereof. The alkali metal may be sodium, potassium, or lithium. The content of such a thickener may be 0.1 to 10 parts by weight per 100 parts by weight of the negative electrode coating composition. The cellulose-based compound may also function as a binder.

[0064] The binder is not limited to these, and any binder used in the relevant technical field can be used, and the content of these can be adjusted as appropriate.

[0065] The binder may be present in an amount of 1 to 15 wt % relative to 100 wt % of the total negative electrode coating layer. For example, the binder may be present in an amount of 1 wt % or more, 2 wt % or more, 3 wt % or more, 4 wt % or more, 5 wt % or more, 6 wt % or more, 7 wt % or more, 8 wt % or more, 9 wt % or more, 10 wt % or more, 11 wt % or more, 12 wt % or more, 13 wt % or more, or 14 wt % or more, and 15 wt % or less, 14 wt % or less, 13 wt % or less, 12 wt % or less, 11 wt % or less, 10 wt % or less, 9 wt % or less, 8 wt % or less, 7 wt % or less, 6 wt % or less, 5 wt % or less, 4 wt % or less, 3 wt % or less, or 2 wt % or less, relative to 100 wt % of the total negative electrode coating layer.

[0066] When the binder is contained in the anode coating layer of an all-solid-state battery in the above content range, electrical resistance and adhesive strength may be improved, thereby improving the characteristics (battery capacity and output characteristics) of the all-solid-state battery.

[0067] The negative electrode coating layer may further include additives such as a filler, a dispersant, etc. In addition, known materials generally used in all-solid-state batteries may be used as the filler, dispersant, etc. that can be included in the negative electrode coating layer.

[0068] According to one embodiment, the negative electrode may further include a lithium-containing layer formed during initial charging after battery fabrication between the current collector and the negative electrode coating layer. The lithium-containing layer may have a thickness of 1 μm to 1000 μm, such as 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 lithium-containing layer has a thickness within this range, it can adequately function as a lithium reservoir, thereby improving the lifespan.

[0069] The lithium-containing layer may be formed by lithium ions being released from the positive electrode active material during charging after the battery is manufactured and then passing through the solid electrolyte to move to the negative electrode, resulting in the deposition and deposition of lithium on the negative electrode current collector.

[0070] The charging process may be a chemical formation process carried out once to three times at about 25° C. to 50° C. and 0.05 C to 1 C. When lithium is deposited and vapor-deposited to form a lithium-containing layer, the lithium contained in the lithium-containing layer ionizes and migrates toward the positive electrode during discharge, and this lithium can be used as a negative electrode active material.

[0071] In one embodiment, the lithium-containing layer is located between the current collector and the negative electrode coating layer, and the negative electrode coating layer can serve as a protective layer for the lithium-containing layer and inhibit the precipitation and growth of lithium dendrites, thereby inhibiting short circuits and capacity degradation in the all-solid-state battery and ultimately improving the cycle life of the all-solid-state battery.

[0072] The current collector may be, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof, and may be in the form of a foil or sheet. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0073] The current collector may be based on the metal and further include a thin film formed on the substrate. The thin film may include 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 the element is capable of forming an alloy with lithium in the relevant technical field. When the current collector further includes a thin film, if the lithium-containing layer is deposited during charging, a more planar lithium-containing layer can be formed, thereby further improving the cycle life of the all-solid-state battery.

[0074] 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 this range, the cycle life characteristics can be further improved.

[0075] The solid electrolyte contained in the solid electrolyte layer may 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 integers of 0 to 12, respectively, and Z is one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are integers of 0 to 12, and M is one of P, Si, Ge, B, Al, Ga, and In), Lia M b P c S d A e (wherein a, b, c, d, and e are each an integer between 0 and 12, inclusive; 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). Specifically, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 etc.

[0077] For example, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte, such as LiaMbPcSdAe (where a, b, c, d, and e are all 0 to 12, M is Ge, Sn, Si, or a combination thereof, and A is one of F, Cl, Br, and 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 etc.

[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. This mixing ratio range allows for the production of a sulfide-based solid electrolyte with excellent ionic conductivity. Additional components such as SiS2, GeS2, and B2S3 may be added to further improve ionic conductivity. Mechanical milling and solution milling can be used as mixing methods. Mechanical milling involves placing starting materials and a ball mill in a reactor and vigorously stirring them to finely grind and mix the starting materials. When using the solution milling method, the starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. After mixing, additional calcination can be performed. Additional calcination can result in a harder crystal of the solid electrolyte.

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

[0080] The oxide-based solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≦x≦4), Li 1+x+y AlxTi 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)、Li1+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 (Garnet) - based ceramics Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10), or mixtures thereof can be included.

[0081] The solid polymer electrolyte is, for example, polyethylene oxy, poly(diallyldimethylammonium) trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, Li3PO4·Li2S·SiS2, Li2S·GeS2·Ga2S3, Li2O·11Al2O3, Na2O·11Al2O3, (Na, Li) 1+x Ti 2-x Al x (PO4)3(0.1 ≤ x ≤ 0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1 ≤ x ≤ 0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na - Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x(M, Al, Ga) x (Ge 1-y Ti y ) 2-x (PO4)3 (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+x A x La 3-x Zr2O 12 (0 < x < 3, A is Zn) can include one or more selected from among them.

[0082] The halide-based solid electrolyte can include 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, for example, 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. Examples of the M include, for example, 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 it may be represented by Li 6-3a MaBr b Cl c (where M is a metal other than Li, 0 < a < 2, 0 ≤ b ≤ 6, 0 ≤ c ≤ 6, b + c = 6). In that case, a can be 0.75 or more, can be 1 or more, and a can be 1.5 or less. b can be 1 or more, can be 2 or more. Also, 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 may be in particulate form and have an average particle size (D50) of 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 include a binder. The binder may be, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate-based polymer, or a combination thereof. Any binder commonly used in the art may be used. The acrylate-based polymer may be butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0086] The solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating the resulting solution on a substrate film, and drying. The solvent for the binder solution can be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The process for forming the solid electrolyte layer is widely known in the art, and therefore, a detailed description thereof will be omitted herein.

[0087] The positive electrode includes a positive electrode current collector and a positive electrode active material layer disposed on one surface of the positive electrode current collector.

[0088] The positive electrode active material layer may include a positive electrode active material. The positive electrode active material may be a positive electrode active material that can reversibly absorb and release lithium ions. For example, the positive electrode active material may be one or more of composite oxides 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 12(0.90≦a≦1.8、0≦b≦0.5);Li a HAVE BEEN 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 HAVE BEEN 2-b B 1 b O 4-c D 1 c (0.90≦a≦1.8、0≦b≦0.5、0≦c≦05);Li a Ni 1-b-c Co b B 1 c D 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α≦2);Li a Ni 1-b-c Co b B 1 cO 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 Mrb 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 E c G d O2(0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, 0.001≦d≦0.1);Li a Ni b Co c L 1 d G e O2(0.90≦a≦1.8, 0≦b≦0.9, 0≦c≦0.5, 0≦d≦0.5, 0≦e≦0.1);Li a NiG b O2(0.90≦a≦1.8, 0.001≦b≦0.1);Li a CoG b O2(0.90≦a≦1.8, 0.001≦b≦0.1);Li a MnG b O2(0.90≦a≦1.8, 0.001≦b≦0.1);Li a Mn2G b O4(0.90≦a≦1.8, 0.001≦b≦0.1);QO2;QS2;LiQS2;V2O5;LiV2O5;LiI 1 O2;LiNiVO4;Li (3-f) J2(PO4)3(0≦f≦2);Li (3-f) Fe2(PO4)3 (0≦f≦2); or LiFePO4.

[0089] In the above 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 combinations thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[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, x + y + z = 1), and other 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 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 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 a mixture thereof can be used. As long as the coating layer formation step can coat the compound with such elements in a method that does not adversely affect the physical properties of the positive electrode active material (for example, spray coating, dipping method, etc.), any coating method can be used, and since this is well understood by those skilled in the art, detailed description is omitted.

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

[0093] Furthermore, when the positive electrode active material is a ternary system containing nickel, cobalt, and manganese, or nickel, cobalt, and aluminum, the capacity density of the all-solid-state battery can be further improved and metal elution from the positive electrode active material in a charged state can be further reduced, thereby improving the long-term reliability and cycle characteristics of the all-solid-state battery in a charged state.

[0094] Here, examples of the shape of the positive electrode active material include particle shapes such as spherical and oval spheres. The average particle size of the positive electrode active material is not particularly limited, and may be within a range applicable to positive electrode active materials of existing all-solid-state secondary batteries. The content of the positive electrode active material in the positive electrode active material layer is also not particularly limited, and may be within a range applicable to positive electrode layers of existing all-solid-state secondary batteries.

[0095] The positive electrode active material layer may further include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer 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.

[0096] The 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.

[0097] The positive electrode active material layer may further include a binder and / or a conductive material.

[0098] Examples of the binder include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylate styrene-butadiene rubber, epoxy resin, and nylon.

[0099] The binder may be included in an amount of 0.1 to 5 wt %, or 0.1 to 3 wt %, based on the total weight of each component of the positive electrode for the all-solid-state battery or the total weight of the positive electrode active material layer. A binder in this content range can sufficiently exhibit adhesive properties without deteriorating battery performance.

[0100] The conductive material is used to impart conductivity to the electrodes, and any material can be used as long as it does not cause a chemical change in the constructed battery and is electronically conductive. Examples of such conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber, carbon nanofiber, and carbon nanotubes; metal-based materials in the form of metal powder or metal fiber containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; and conductive materials containing mixtures thereof.

[0101] The conductive material may be included in an amount of 0.1 to 5 wt %, or 0.1 to 3 wt %, based on the total weight of each component of the positive electrode for the all-solid-state battery or the total weight of the positive electrode active material layer. The conductive material in this content range can improve conductivity without deteriorating battery performance.

[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 or more, 100 μm or more, 110 μm or more, 120 μm or more, 130 μm or more, 140 μm or more, 150 μm or more, 160 μm or more, 170 μm or more, 180 μm or more, or 190 μm or more, and may be 200 μm or less, 190 μm or less, 180 μm or less, 170 μm or less, 160 μm or less, 150 μm or less, 140 μm or less, 130 μm or less, 120 μm or less, or 110 μm or less.

[0103] As described above, the thickness of the positive electrode active material layer is greater than the thickness of the negative electrode coating layer, and therefore the capacity of the positive electrode is greater than the capacity of the negative electrode.

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

[0105] In one embodiment, a buffer material may be further included to buffer thickness changes that occur during charging and discharging of the all-solid-state battery. The buffer 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, the buffer material may be located between different electrode assemblies.

[0106] The buffer material may be a material having an elastic recovery rate of 50% or more and having an insulating function, such as silicone rubber, acrylic rubber, fluorine-based rubber, nylon, synthetic rubber, or a combination thereof. The buffer material may be in the form of a polymer sheet.

[0107] FIG. 1 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 1, the all-solid-state battery 100 may have a structure in which an electrode assembly including a stack of an anode 400 including an anode current collector 401 and an anode coating layer 403, a solid electrolyte layer 300, and a cathode 200 including a cathode active material layer 203 and a cathode current collector 201 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 surface of at least one of the cathode 200 and the anode 400. Although FIG. 1 shows one electrode assembly including the anode 400, the solid electrolyte layer 300, and the cathode 200, two or more electrode assemblies may be stacked to fabricate an all-solid-state battery.

[0108] 2 is a schematic diagram showing the structure of 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 current collector 401, a negative electrode 400 including a negative electrode coating layer 403, and a solid electrolyte 300 located between the positive electrode 200 and the negative electrode 400, and a battery case 500 that houses these components.

[0109] When such an all-solid-state battery 100 is charged, as shown in FIG. 2, lithium ions are released from the positive electrode active material and deposited on the negative electrode current collector 401′, resulting in the formation of a lithium deposition layer 405′ between the current collector 401′ and the negative electrode coating layer 403′.

[0110] An all-solid-state battery according to an embodiment may be manufactured by preparing a stack by positioning an anode, a cathode, and a solid electrolyte layer between the anode and the cathode, and pressing the stack.

[0111] The pressing step may be carried out at a temperature ranging from 25°C to 90°C. The pressing step may be carried out at a pressure of 550 MPa or less, for example, 500 MPa or less, for example, in the range of 1 MPa to 500 MPa. The pressing time may vary depending on the temperature and pressure, and may be, for example, less than 30 minutes. The pressing step may be carried out by, for example, isostatic pressing, roll pressing, plate pressing, or warm isostatic pressing. [Example]

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

[0113] Example 1 (1) Manufacturing of the negative electrode Carbon black and 2-naphthalenethiol powder were mixed in a 10:1 weight ratio. This mixture was heat-treated at 90°C. AgNO3 and NaBH4 reducing agents were added to the heat-treated product in an aqueous solvent to produce a supported product. In this case, AgNO3 was used in an amount of 11 wt% relative to the total weight of Ag and carbon black (100 wt%) in the supported product. The amount of NaBH4 reducing agent used was 22 wt% relative to the total weight of AgNO3 (100 wt%).

[0114] The resulting mixture was heat-treated at 400°C for 4 hours under a nitrogen atmosphere to prepare an anode coating composition, which contained 5 wt% silver, 88 wt% carbon black, and 1.1 wt% sulfur.

[0115] The negative electrode coating composition, styrene butadiene rubber, and sodium carboxymethyl cellulose were mixed in a weight ratio of 100:6:3 with an aqueous solvent to prepare a negative electrode coating slurry.

[0116] The prepared slurry was coated onto a stainless steel foil current collector and then vacuum dried at 80°C to prepare a negative electrode including a 12 μm thick negative electrode coating layer and a 10 μm thick current collector. The thickness of the negative electrode coating layer was 12 μm.

[0117] (2) Manufacturing of solid electrolyte layer The ajirodite-type solid electrolyte Li6PS5Cl was mixed with an isobutylyl isobutylate binder solution (solid content: 50 wt%) containing butyl acrylate, an acrylate polymer. The mixing ratio of the solid electrolyte to the binder was 98.7:1.3 by weight.

[0118] The mixing process was carried out using a Thinky mixer. 2 mm zirconia balls were added to the resulting mixture, and the mixture was stirred again using the Thinky mixer to prepare a slurry. The slurry was cast onto a release polytetrafluoroethylene film and dried at room temperature to prepare a solid electrolyte layer with a thickness of 100 μm.

[0119] (3) Manufacturing of the positive electrode LZO (Li-doped zinc oxide) coated positive electrode active material (LiNi 0.9 Mn 0.05 Co 0.05 O2), a mixture of adilotite-type solid electrolyte Li6PS5Cl, conductive carbon nanofiber, and binder polytetrafluoroethylene in a weight ratio of 85:15:3:1.5 was prepared.

[0120] The resulting 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 positive electrode active material layer and a 10 μm-thick current collector. The positive electrode active material layer had a thickness of 12 μm.

[0121] (4) Manufacturing of all-solid-state full cells The prepared negative electrode, solid electrolyte, and counter positive electrode were sequentially stacked, and a pressure of 8 MPa was applied to prepare an all-solid-state battery.

[0122] (Comparative Example 1) Carbon black and Ag were mechanically mixed in a 75:25 weight ratio using a mortar to prepare a negative electrode coating composition. The silver content in the prepared negative electrode coating composition was 25 wt % and the carbon black content was 75 wt %.

[0123] A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the negative electrode coating composition was used.

[0124] (Comparative Example 2) Carbon black and 2-naphthalenethiol powder were mixed in a 10:1 weight ratio. This mixture was heat-treated at 90°C. AgNO3 and NaBH4 reducing agents were added to the heat-treated product in an aqueous solvent to produce a supported product. The amount of AgNO3 used was 11 wt% relative to the total weight of Ag and carbon black in the supported product (100 wt%). The amount of NaBH4 reducing agent used was 22 wt% relative to the total weight of AgNO3 (100 wt%).

[0125] A negative electrode and an all-solid-state battery were fabricated in the same manner as in Example 1, except that the supported product was used as a negative electrode coating composition.

[0126] (Comparative Example 3) 50 mL of glycerol (99.9%, Aldrich) and 0.5 mM polyvinylpyrrolidone (weight average molecular weight (Mw): 55,000, Aldrich) were added to a 100 mL reaction vessel and heated to 80°C. The resulting mixture was mixed until a clear solution was obtained and then cooled to 30°C. 5 g of carbon black was then added to the reaction mixture and mixed for 10 minutes, after which 50 mM AgNO3 (99.9%, Aldrich) was added and mixed for 5 minutes. The temperature of the mixture was raised to 100°C and then allowed to stand for 12 hours.

[0127] Next, 50 mL of deionized water was added to the reaction product, and sonication was performed for 2 minutes. Next, glycerol and polyvinylpyrrolidone were separated from the carbon black using a glass filter, and the silver-loaded carbon black was washed with ethanol and deionized water to remove any remaining components.

[0128] The washed product was dried in a vacuum oven at 90° C. for 8 hours or more to prepare a negative electrode coating composition, which had a silver content of 5 wt % and a carbon content of 95 wt %.

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

[0130] Comparative Example 4 A negative electrode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that only carbon black was used as the negative electrode coating composition.

[0131] Experimental Example 1) SEM photo SEM photographs of the negative electrode coating compositions prepared in Example 1 and Comparative Example 1 are shown in FIGS. 3 and 4, respectively.

[0132] As shown in Figure 3, the silver is uniformly dispersed in the carbon black in the anode coating composition prepared in Example 1. In contrast, as shown in Figure 4, the silver is concentrated in some areas on the surface in the anode coating composition prepared in Comparative Example 1.

[0133] Experimental Example 2) X-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy (XPS) evaluation XPS S2p spectra were measured for the anode coating compositions prepared in Example 1, Comparative Examples 1, and Comparative Examples 2. The results are shown in Figure 5. As shown in Figure 5, in Comparative Example 1, in which carbon black and Ag were simply mixed, Ag-S and C-S bonds were absent, whereas in Example 1, in which carbon black and Ag were chemically bonded via S, Ag-S bonds were present. Additionally, in Comparative Example 2, in which no heat treatment at 400°C was performed, C-S bonds, S-S bonds, and Ag-S bonds were all present.

[0134] Experimental Example 3) Evaluation of resistance density The resistance of the all-solid-state batteries of Example 1 and Comparative Examples 1 to 3 was measured using a powder conductivity measurement method. The measurement results are shown in Table 1 below.

[0135] [Table 1]

[0136] As shown in Table 1, the resistance value of Comparative Example 3, in which silver and oxygen are bonded, is much higher than that of Example 1. In particular, the resistance value of Comparative Example 3 was higher than that of Comparative Example 2, in which no sulfur-metal bond was formed by heat treatment.

[0137] It can be seen that Comparative Example 2, in which no bond between sulfur and metal is formed, also exhibits a high resistance value, and therefore exhibits deteriorated rate characteristics.

[0138] In addition, it can be seen that the heat treatment formed bonds between silver and sulfur, which resulted in uniform distribution of the carbon black and uniform distribution of current in the negative electrode, resulting in a very low resistance value after heat treatment in Example 1.

[0139] It is also clear that the resistance value after heat treatment of Example 1 is lower than the resistance value of Comparative Example 1 in which carbon black and silver were simply mixed.

[0140] Experimental Example 4) Thermogravimetric Analysis (TGA) analysis) Thermogravimetric analysis (TGA) was performed on the anode coating composition before and after heat treatment in the process for preparing the anode coating composition in Example 1. The weight percent change results are shown in Figure 6, and derivative thermogravimetry (DTG, % / min) values ​​are shown in Figure 7. The thermogravimetric analysis was performed in an argon atmosphere, starting at room temperature (25°C) in a N2 atmosphere and ramping up to 900°C at a rate of 10°C / min.

[0141] 6 and 7, the product before the heat treatment lost 8.9 wt %, while the anode coating composition after the heat treatment did not lose any weight. This weight loss is believed to be the result of the thiol compound, which indicates that the thiol compound present before the heat treatment essentially does not remain after the heat treatment.

[0142] Although the preferred embodiment of the present invention has been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and it is natural that these also fall within the scope of the present invention.

Claims

1. Contains metals and carbon-based materials, the metal and the carbon-based substance are chemically bonded via sulfur; Anode coating composition for all-solid-state batteries.

2. 2. The negative electrode coating composition for an all-solid-state battery according to claim 1, wherein the negative electrode coating composition has a peak associated with a metal-sulfur bond in a spectrum obtained by XPS analysis.

3. 2. The negative electrode coating composition for an all-solid-state battery according to claim 1, wherein the negative electrode coating composition has a peak appearing at a binding energy of 160 eV to 162 eV in an S2p spectrum obtained by XPS analysis.

4. The coating composition for an anode of an all-solid-state battery according to claim 1 , wherein the carbon-based material is amorphous carbon, crystalline carbon, or a mixture thereof.

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

6. 2. The coating composition for an anode of an all-solid-state battery according to claim 1, wherein the content of the metal is 3 wt% to 40 wt% based on 100 wt% of the total content of the metal and the carbon-based material.

7. mixing a carbonaceous material and a sulfur source material to produce a mixture; loading a metal onto the mixture to produce a loaded product; heat treating the supported product; A method for producing a negative electrode coating composition for an all-solid-state battery, comprising:

8. The method of claim 7, wherein the sulfur source material is a thiol compound, a sulfide-based compound, a thiophene-based compound, a sulfonic acid, a sulfone, a sulfoxide, or a combination thereof.

9. The method according to claim 7, wherein the heat treatment step is carried out at a temperature of 100°C to 500°C.

10. a negative electrode comprising a current collector and a negative electrode coating layer disposed on one side of the current collector; a positive electrode; and a solid electrolyte layer located between the negative electrode and the positive electrode; 7. An all-solid-state battery, wherein the negative electrode coating layer comprises the negative electrode coating composition according to any one of items 1 to 6.

11. The all-solid-state battery according to claim 10 , wherein the solid electrolyte is a sulfide-based solid electrolyte.

12. The all-solid-state battery according to claim 10, further comprising a lithium-containing layer formed between the current collector and the negative electrode coating layer during initial charging.

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