Positive electrode active material, method for producing same, and secondary battery comprising same

Abstract

Provided are a positive electrode active material, a method for preparing same, and a secondary battery comprising same, the positive electrode active material comprising: primary particles containing a sulfur-based complex; and secondary particles comprising the primary particles and a first solid electrolyte, wherein the sulfur-based complex is a composite of a sulfur-based substance, a metal halide salt, and a carbon-based conductive material, the sulfur-based substance includes at least one of S8 and Li2Sn (1 ≤ n ≤ 8, where n is an integer), the metal halide salt includes an alkali metal salt and a boron-group metal salt, and the secondary particles have a D10 of 5 μm or greater.

Description

Anode active material, method of manufacturing the same, and secondary battery including the same

[0001] The invention relates to a positive electrode active material, a method for manufacturing the same, and a secondary battery containing the same.

[0002] Recently, driven by industrial demands, the development of batteries with high energy density and safety is actively underway. For example, lithium batteries are used in various applications, including information devices, communication equipment, and automobiles. Since automobiles are a matter of life and death, safety is also critical.

[0003] Lithium batteries using liquid electrolytes may have an increased risk of fire and / or explosion in the event of a short circuit. Solid-state rechargeable batteries employing solid electrolytes instead of liquid electrolytes are being proposed. Solid electrolytes have a lower risk of ignition compared to liquid electrolytes.

[0004] Solid-state secondary batteries can reduce the possibility of fire or explosion by employing a solid electrolyte instead of a liquid electrolyte. Solid-state batteries can provide enhanced safety.

[0005] One aspect is to provide a positive electrode active material with a reduced proportion of fine particles with small particle sizes.

[0006] Another aspect is to provide a method for manufacturing an all-solid-state battery comprising a positive electrode active material with reduced fine particles of small particle size.

[0007] According to one embodiment, a primary particle comprising a sulfur-based complex; and a secondary particle comprising the primary particle and a first solid electrolyte, wherein the sulfur-based complex is a complex of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, and the sulfur-based material is S8 and Li2S nA positive electrode active material is provided that includes at least one of (1 ≤ n ≤ 8, where n is an integer), wherein the metal halide salt includes an alkali metal salt and a boron group metal salt, and the D10 of the secondary particle is 5 μm or more.

[0008] According to another embodiment, a secondary battery is provided comprising: a positive electrode including a positive current collector and a positive active material layer on the positive current collector; a negative electrode; and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the positive active material layer comprises a positive active material according to claim 1.

[0009] According to another embodiment, the method comprises ball-milling a composition containing a sulfur-based material to produce primary particles containing a sulfur-containing composite; and granulating the primary particles together with a solid electrolyte to produce secondary particles, wherein the sulfur-containing composite is a composite of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, and the sulfur-based material is S8 and Li2S n A method for manufacturing an anode active material is provided, comprising at least one of (1 ≤ n ≤ 8, where n is an integer), wherein the metal halide salt comprises an alkali metal salt and a boron group metal salt, and the D10 of the secondary particle is 5 μm or more.

[0010]

[0011] According to one aspect, the positive electrode active material has a low proportion of fine particles with small particle sizes, thereby reducing side reactions caused by fine particles, and has excellent ion and electron conductivity, making it possible to provide an all-solid-state battery having improved charge and discharge characteristics.

[0012]

[0013] FIG. 1 is a conceptual diagram illustrating the composition of a positive electrode active material according to an exemplary embodiment.

[0014] FIG. 2 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0015] FIG. 3 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0016] The present inventive concept described below is subject to various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present inventive concept to specific embodiments and should be understood to include all modifications, equivalents, or substitutions that fall within the scope of the description of the present inventive concept.

[0017] The terms used below are used merely to describe specific embodiments and are not intended to limit the creative concept. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the following, terms such as “comprising” or “having” are intended to indicate the existence of the features, numbers, steps, actions, components, parts, components, materials, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, components, materials, or combinations thereof. The “ / ” used below may be interpreted as “and” or “or” depending on the context.

[0018] In the drawings, thicknesses have been enlarged or reduced to clearly represent various layers and regions. Throughout the specification, the same reference numerals have been used for similar parts. Throughout the specification, when a part such as a layer, film, region, or plate is described as being “on” or “above” another part, this includes not only cases where it is directly above another part but also cases where there is another part in between. Throughout the specification, terms such as “first,” “second,” etc., may be used to describe various components, but the components should not be limited by these terms. In this specification and drawings, components having substantially the same functional configuration are referred to by the same reference numerals to avoid redundant descriptions.

[0019] In the present disclosure, the “size” of a particle is, for example, the “particle diameter” of the particle. The “particle diameter” of the particle represents the average diameter when the particle is spherical and represents the average major axis length when the particle is non-spherical. The particle diameter of the particle can be measured using a particle size analyzer (PSA). The “particle diameter” of the particle is, for example, the average particle diameter. The average particle diameter is, for example, the median particle diameter (D50).

[0020] The median particle diameter (D50) is the particle size corresponding to 50% of the cumulative volume, calculated from the particle side having a small particle size in the particle size distribution measured by, for example, laser diffraction.

[0021] The median particle diameter (D90) is the particle size corresponding to 90% of the cumulative volume, calculated from the particle side having a small particle size in the particle size distribution measured by, for example, laser diffraction.

[0022] The median particle diameter (D10) is the particle size corresponding to 10% of the cumulative volume, calculated from the particle side having a small particle size in the particle size distribution measured by, for example, laser diffraction.

[0023] In the present disclosure, “metal” includes both metals and metalloids such as silicon and germanium in an elemental or ionic state.

[0024] In this disclosure, “alloy” means a mixture of two or more metals.

[0025] In the present disclosure, “anode active material” refers to an anode material capable of undergoing lithiation and delithiation.

[0026] In the present disclosure, “anode active material” refers to an anode material capable of undergoing lithiation and delithiation.

[0027] In the present disclosure, “lithiation” and “to lithiate” refer to the process of adding lithium to a positive electrode active material or a negative electrode active material.

[0028] In the present disclosure, “delithiation” and “to delithiate” refer to the process of removing lithium from a positive electrode active material or a negative electrode active material.

[0029] In this disclosure, “charge” and “to charge” refer to the process of providing electrochemical energy to a battery.

[0030] In this disclosure, “anode” and “cathode” refer to electrodes where electrochemical reduction and lithiation occur during the discharge process.

[0031] In this disclosure, “cathode” and “anode” refer to electrodes where electrochemical oxidation and delithiation occur during the discharge process.

[0032] A positive electrode active material according to exemplary embodiments, a method for manufacturing the same, and an all-solid-state battery including the same will be described in more detail below.

[0033] FIG. 2 is a cross-sectional view of a lithium secondary battery according to one embodiment. Referring to FIG. 2, a lithium secondary battery according to one embodiment may include a positive electrode (100); a negative electrode (200); and an electrolyte layer (300) disposed between the positive electrode (100) and the negative electrode (200). The positive electrode (100) according to one embodiment may include a positive current collector (110); and a positive active material layer (120) on the positive current collector (110). The positive active material layer (120) may include a positive active material according to one embodiment.

[0034] [Cathode active material]

[0035] A positive electrode active material according to one embodiment comprises a primary particle (PTC1) comprising a sulfur-based complex; and a secondary particle (PTC2) comprising the primary particle and a first solid electrolyte (SE1); wherein the sulfur-based complex is a complex of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, and the sulfur-based material is S8 and Li2S n It includes at least one of (1 ≤ n ≤ 8, where n is an integer), and the metal halide salt may include an alkali metal salt and a boron group metal salt. The D10 of the secondary particle (PTC2) may be 5 μm or more.

[0036] According to one embodiment, the primary particle (PTC1) may include a sulfur-based complex. According to one embodiment, the sulfur-based complex may be a complex of a sulfur-based material, a metal halide salt, and a carbon-based conductive material. According to one embodiment, the sulfur-based complex may be a complex of Li2S, a metal halide salt, and a carbon-based conductive material. The metal halide salt may include an alkali metal salt and a boron group metal salt.

[0037] The sulfur-containing composite may be, for example, the result of mechanical milling of a sulfur-based material, a metal halide salt, and a carbon-based conductive material. Since the sulfur-containing composite is, for example, the result of a mechanochemical reaction of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, it can be distinguished from a simple mixture of a sulfur-based material, a metal halide salt, and a carbon-based conductive material. A simple mixture of a sulfur-based material, a metal halide salt, and a carbon-based conductive material may increase the internal resistance of the cathode active material by providing high interfacial resistance due to the inability to maintain a dense interface between the sulfur-based material, the metal halide salt, and the carbon-based conductive material.

[0038] Sulfur-based materials may include elemental sulfur (S) and / or sulfur compounds. Sulfur is attracting attention as a next-generation cathode material due to its high theoretical capacity (1,672 mAh / g), its abundance on Earth, and its relatively low cost. In one embodiment, the elemental sulfur (S) is S8 and Li2S n It may exist in the form of a sulfur-based material comprising at least one of (1 ≤ n ≤ 8, where n is an integer). That is, the sulfur-based material according to one embodiment is S8 and Li2S nIt may include at least one of (1 ≤ n ≤ 8, where n is an integer). A sulfur-based material according to one embodiment may include Li2S. A continuous oxidation / reduction reaction of sulfur and / or sulfur compounds proceeds in the sulfur-based material. For example, the reaction process of lithium polysulfide and lithium sulfide by the continuous reduction reaction of sulfur can be expressed as S8→Li2S8→Li2S6→Li2S4→Li2S2→Li2S, etc. In this process, lithium ions move between the anode and cathode, and at the same time, electrons move through an external circuit, which can generate an electric current. By including such a sulfur-based material in the sulfur-containing composite, the capacity characteristics of the sulfur-containing composite can be further improved. Consequently, the energy density of an all-solid-state battery containing such a sulfur-containing composite can be improved.

[0039] Metal halide salts may include alkali metal salts and boron group metal salts. That is, the sulfur-containing composite may be a composite of a sulfur-based material, an alkali metal salt, a boron group metal salt, and a carbon-based conductive material.

[0040] The alkali metal salt according to one embodiment may be a lithium salt. The alkali metal salt may include, for example, LiF, LiCl, LiBr, LiI, or a combination thereof. The alkali metal salt may be, for example, a compound that does not contain sulfur (S). The ionic conductivity of the sulfur-containing complex may be further enhanced by the inclusion of such an alkali metal salt in the sulfur-containing complex.

[0041] A boron group metal salt according to one embodiment may be, for example, a binary compound composed of a boron group metal and one element selected from Group 17 of the periodic table. The boron group metal salt may include, for example, AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, GaI3, InF3, InCl3, lnBr3, lnI3, TlF3, TlCl3, TlBr3, TlI3, or a combination thereof. By including such a boron group metal salt in the sulfur-containing complex, the overall structure of the sulfur-containing complex can be maintained, allowing for the easy formation of a solid solution and lowering interfacial resistance.

[0042] Carbon-based conductive materials may be any material containing carbon atoms, for example, used as a carbon-based conductive material in the relevant technical field. Carbon-based conductive materials may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. Carbon-based conductive materials may be, for example, a sintered product of a carbon precursor. Carbon-based conductive materials may be, for example, carbon nanostructures. Carbon nanostructures may be, for example, one-dimensional carbon nanostructures, two-dimensional carbon nanostructures, three-dimensional carbon nanostructures, or a combination thereof. Carbon nanostructures may be, for example, carbon nanotubes (CNT), carbon nanofibers (CNF), carbon nanobelts, carbon nanorods, graphene, or a combination thereof. Carbon-based conductive materials may be, for example, porous carbon-based conductive materials or non-porous carbon-based conductive materials. Porous carbon-based conductive materials may include, for example, periodic and regular two-dimensional or three-dimensional pores. The porous carbon-based conductive material may be, for example, carbon black such as Ketjen black, acetylene black, Denka black, thermal black, or channel black; graphite, activated carbon, or a combination thereof. The form of the carbon-based conductive material may be, for example, particle form, sheet form, flake form, etc., but is not limited thereto; any form used as a carbon-based conductive material in the relevant technical field is possible. The carbon-based conductive material according to one embodiment may include, for example, a fibrous carbon-based conductive material. By including a fibrous carbon-based conductive material in the sulfur-containing composite, electron conduction from the surface to the interior of the sulfur-containing composite can be performed more easily.

[0043] 황 함유 복합체는 예를 들어, Li2S-LiF-CNT, Li2S-LiCl-CNT, Li2S-LiBr-CNT, Li2S-LiI-CNT, Li2S-LiF-CNF, Li2S-LiCl-CNF, Li2S-LiBr-CNF, Li2S-LiI-CNF, Li2S-LiF-AlF3-CNT, Li2S-LiF-AlCl3-CNT, Li2S-LiF-AlBr3-CNT, Li2S-LiF-AlI3-CNT, Li2S-LiF-GaF3-CNT, Li2S-LiF-GaCl3-CNT, Li2S-LiF-GaBr3-CNT, Li2S-LiF-GaI3-CNT, Li2S-LiF-InF3-CNT, Li2S-LiF-InCl3-CNT, Li2S-LiF-InBr3-CNT, Li2S-LiF-InI3-CNT, Li2S-LiF-TlF3-CNT, Li2S-LiF-TlCl3-CNT, Li2S-LiF-TlBr3-CNT, Li2S-LiF-TlI3-CNT, Li2S-LiCl-AlF3-CNT, Li2S-LiCl-AlCl3-CNT, Li2S-LiCl-AlBr3-CNT, Li2S-LiCl-AlI3-CNT, Li2S-LiCl-GaF3-CNT, Li2S-LiCl-GaCl3-CNT, Li2S-LiCl-GaBr3-CNT, Li2S-LiCl-GaI3-CNT, Li2S-LiCl-InF3-CNT, Li2S-LiCl-InCl3-CNT, Li2S-LiCl-InBr3-CNT, Li2S-LiCl-InI3-CNT, Li2S-LiCl-TlF3-CNT, Li2S-LiCl-TlCl3-CNT, Li2S-LiCl-TlBr3-CNT, Li2S-LiCl-TlI3-CNT, Li2S-LiBr-AlF3-CNT, Li2S-LiBr-AlCl3-CNT, Li2S-LiBr-AlBr3-CNT, Li2S-LiBr-AlI3-CNT, Li2S-LiBr-GaF3-CNT, Li2S-LiBr-GaCl3-CNT, Li2S-LiBr-GaBr3-CNT, Li2S-LiBr-GaI3-CNT, Li2S-LiBr-InF3-CNT, Li2S-LiBr-InCl3-CNT, Li2S-LiBr-InBr3-CNT,Li2S-LiBr-InI3-CNT, Li2S-LiBr-TlF3-CNT, Li2S-LiBr-TlCl3-CNT, Li2S-LiBr-TlBr3-CNT, Li2S-LiBr-TlI3-CNT, Li2S-LiI-AlF3-CNT, Li2S-LiI-AlCl3-CNT, Li2S-LiI-AlBr3-CNT, Li2S-LiI-AlI3-CNT, Li2S-LiI-GaF3-CNT, Li2S-LiI-GaCl3-CNT, Li2S-LiI-GaBr3-CNT, Li2S-LiI-GaI3-CNT, Li2S-LiI-InF3-CNT, Li2S-LiI-InCl3-CNT, Li2S-LiI-InBr3-CNT, Li2S-LiI-InI3-CNT, Li2S-LiI-TlF3-CNT, Li2S-LiI-TlCl3-CNT, Li2S-LiI-TlBr3-CNT, Li2S-LiI-TlI3-CNT, Li2S-LiF-AlF3-CNF, Li2S-LiF-AlCl3-CNF, Li2S-LiF-AlBr3-CNF, Li2S-LiF-AlI3-CNF, Li2S-LiF-GaF3-CNF, Li2S-LiF-GaCl3-CNF, Li2S-LiF-GaBr3-CNF, Li2S-LiF-GaI3-CNF, Li2S-LiF-InF3-CNF, Li2S-LiF-InCl3-CNF, Li2S-LiF-InBr3-CNF, Li2S-LiF-InI3-CNF, Li2S-LiF-TlF3-CNF, Li2S-LiF-TlCl3-CNF, Li2S-LiF-TlBr3-CNF, Li2S-LiF-TlI3-CNF, Li2S-LiCl-AlF3-CNF, Li2S-LiCl-AlCl3-CNF, Li2S-LiCl-AlBr3-CNF, Li2S-LiCl-AlI3-CNF, Li2S-LiCl-GaF3-CNF, Li2S-LiCl-GaCl3-CNF, Li2S-LiCl-GaBr3-CNF, Li2S-LiCl-GaI3-CNF, Li2S-LiCl-InF3-CNF, Li2S-LiCl-InCl3-CNF, Li2S-LiCl-InBr3-CNF, Li2S-LiCl-InI3-CNF, Li2S-LiCl-TlF3-CNF,Li2S-LiCl-TlCl3-CNF, Li2S-LiCl-TlBr3-CNF, Li2S-LiCl-TlI3-CNF, Li2S-LiBr-AlF3-CNF, Li2S-LiBr-AlCl3-CNF, Li2S-LiBr-AlBr3-CNF, Li2S-LiBr-AlI3-CNF, Li2S-LiBr-GaF3-CNF, Li2S-LiBr-GaCl3-CNF, Li2S-LiBr-GaBr3-CNF, Li2S-LiBr-GaI3-CNF, Li2S-LiBr-InF3-CNF, Li2S-LiBr-InCl3-CNF, Li2S-LiBr-InBr3-CNF, Li2S-LiBr-InI3-CNF, Li2S-LiBr-TlF3-CNF, Li2S-LiBr-TlCl3-CNF, Li2S-LiBr-TlBr3-CNF, Li2S-LiBr-TlI3-CNF, Li2S-LiI-AlF3-CNF, Li2S-LiI-AlCl3-CNF, Li2S-LiI-AlBr3-CNF, Li2S-LiI-AlI3-CNF, Li2S-LiI-GaF3-CNF, Li2S-LiI-GaCl3-CNF, Li2S-LiI-GaBr3-CNF, Li2S-LiI-GaI3-CNF, Li2S-LiI-InF3-CNF, Li2S-LiI-InCl3-CNF, Li2S-LiI-InBr3-CNF, Li2S-LiI-InI3-CNF, Li2S-LiI-TlF3-CNF, Li2S-LiI-TlCl3-CNF, Li2S-LiI-TlBr3-CNF, Li2S-LiI-TlI3-CNF 또는 이들의 조합을 포함할 수 있다.,

[0044] The sulfur-containing composite may include, for example, a solid solution of a sulfur-based material, a metal halide salt, and a carbon-based conductive material. The ionic conductivity and electrical conductivity of the sulfur-containing composite may be enhanced by the inclusion of the solid solution of the sulfur-based material, the metal halide salt, and the carbon-based conductive material. For example, the ionic conductivity and electrical conductivity of the solid solution of the sulfur-based material, the metal halide salt, and the carbon-based conductive material may be enhanced compared to the ionic conductivity and electrical conductivity of the sulfur-based material by including lithium ions disposed within the crystallites of the sulfur-based material. Consequently, the ionic conductivity and electrical conductivity of the sulfur-containing composite may be enhanced.

[0045] Since sulfur-based materials have relatively low ionic conductivity, they form complexes with metal halide salts to improve ionic conductivity. A complex of sulfur-based materials, metal halide salts, and carbon-based conductive materials can provide improved ionic conductivity compared to the sulfur-based material alone.

[0046] The molar ratio of the sulfur-based material to the metal halide salt in the sulfur-containing composite may be, for example, 50:50 to 95:5, 60:40 to 95:5, 60:40 to 90:10, 65:35 to 90:10, 65:35 to 85:15, or 70:30 to 85:15. The molar ratio of the sulfur-based material to the metal halide salt in the sulfur-containing composite may be, for example, 50:50 to 95:5, 50:50 to 90:10, 50:50 to 85:15, 50:50 to 80:20, 50:50 to 75:25, or 50:50 to 70:30. By having the sulfur-based material and the metal halide salt in this range of molar ratios, the cycle characteristics of an all-solid-state lithium battery including a dry cathode film can be further improved. If the molar ratio of sulfur-based materials is excessively high, the effect of improving ion conductivity by metal halide salts may be negligible. If the molar ratio of sulfur-based materials is excessively high, the energy density of the lithium battery containing the cathode active material may decrease.

[0047] The content of sulfur-based materials in the sulfur-containing complex may be 50 to 90 wt% or 50 to 80 wt% of the total weight of the sulfur-containing complex. Alternatively, the content of sulfur-based materials in the sulfur-containing complex may be 60 to 90 mol% or 70 to 80 mol% of the total molar amount of the sulfur-containing complex. The sulfur-containing complex may provide enhanced ionic conductivity by having a content of sulfur-based materials within these ranges.

[0048] The content of the metal halide salt in the sulfur-containing complex may be 10 to 50 wt% or 20 to 50 wt% of the total weight of the sulfur-containing complex. Alternatively, the content of the metal halide salt in the sulfur-containing complex may be 1 to 10 mol% or 5 to 7 mol% of the total molar amount of the sulfur-containing complex. The sulfur-containing complex may provide enhanced ionic conductivity by having a content of metal halide salt within these ranges.

[0049] According to one embodiment, the weight ratio of the alkali metal salt to the boron group metal salt in the metal halide salt may be 5:1 to 1:20. For example, the weight ratio of the alkali metal salt to the boron group metal salt in the metal halide salt may be 3:1 to 1:9, 1:1 to 1:9, or 1:2 to 1:4. When satisfying the above ranges, the effect of improving capacity characteristics can be maximized by including different types of metal halide salts in appropriate proportions.

[0050] According to one embodiment, the molar ratio of the alkali metal salt to the boron group metal salt in the metal halide salt may be 10:1 to 1:10. For example, the molar ratio of the alkali metal salt to the boron group metal salt in the metal halide salt may be 5:1 to 1:5, 3:1 to 1:3, or 2:1 to 1:2. When satisfying the above ranges, the effect of improving capacity characteristics can be maximized by including different types of metal halide salts in appropriate proportions.

[0051] Since sulfur-based materials have relatively low electronic conductivity, they form a composite with a carbon-based conductive material to improve electronic conductivity. A composite of a sulfur-based material, a metal halide salt, and a carbon-based conductive material can provide improved electronic conductivity compared to the sulfur-based material alone. The content of the carbon-based conductive material in the sulfur-containing composite may be 1 to 30 wt%, 1 to 20 wt%, or 5 to 20 wt% of the total weight of the sulfur-containing composite. Alternatively, the content of the carbon-based conductive material in the sulfur-containing composite may be 1 to 30 mol%, 10 to 30 mol%, or 15 to 25 mol% of the total molar amount of the sulfur-containing composite. The sulfur-containing composite may provide improved electronic conductivity by having a content of carbon-based conductive material within these ranges.

[0052] A first solid electrolyte (SE1) according to one embodiment may include a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. The sulfide-based solid electrolyte is, for example, Li2S-P2S5, Li2S-P2S5-LiX, where X is a halogen element, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n , m, n are positive numbers, Z is one of Ge, Zn, or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, In, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I xIt is one or more selected from (0≤x≤2). Sulfide-based solid electrolytes can be produced by processing starting materials, such as Li2S or P2S5, by methods such as melt quenching or mechanical milling. Additionally, heat treatment may be performed after such processing. Sulfide-based solid electrolytes may be amorphous, crystalline, or a mixture thereof. Sulfide-based solid electrolytes may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements. Sulfide-based solid electrolytes may include, for example, Li2S-P2S5. When using a material containing Li2S-P2S5 as a sulfide-based solid electrolyte, the molar ratio of Li2S and P2S5 is, for example, in the range of Li2S : P2S5 = 20 : 80 to 90 : 10, 25 : 75 to 90 : 10, 30 : 70 to 70 : 30, and 40 : 60 to 60 : 40.

[0053] Sulfide-based solid electrolytes may include, for example, an argyrodite-type solid electrolyte represented by the following chemical formula 1:

[0054] <Chemical Formula 1>

[0055] Li + 12-n-x A n+ X 2- 6-x Y - x

[0056] In the above formula, A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta; X is S, Se, or Te; Y is Cl, Br, I, F, CN, OCN, SCN, or N3; and 1≤n≤5, 0≤x≤2. Sulfide-based solid electrolytes are, for example, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-x PS 6-x Brx , 0≤x≤2, and Li 7-x PS 6-x I x It may be an argyrodite type compound containing one or more selected from 0≤x≤2. The sulfide-based solid electrolyte may be an argyrodite type compound containing, for example, one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0057] The density of the argyrodite-type solid electrolyte may be 1.5 to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or higher, the internal resistance of the all-solid-state battery is reduced, and penetration of the solid electrolyte separator by lithium can be suppressed more effectively.

[0058] Referring to FIG. 1, a secondary particle (PTC2) according to one embodiment can be manufactured by aggregating the primary particle (PTC1) described above and the first solid electrolyte (SE1) into the secondary particle (PTC2). Although the method of aggregating the primary particle (PTC1) and the first solid electrolyte (SE1) into the secondary particle (PTC2) is not particularly limited, the secondary particle (PTC2) can be manufactured by granulating the primary particle (PTC1) containing the sulfur-containing composite and the first solid electrolyte (SE1) using a mixer such as the NOBILTA MINI of Hosokawa Micron and the Hybridization system of NARA.

[0059] According to one embodiment, the D10 of the secondary particle (PTC2) may be 5 μm or more. As the D10 of the secondary particle (PTC2) is controlled to be 5 μm or more, the proportion of fine particles is reduced, and side reactions caused by fine particles can be suppressed. In addition, the contact between the sulfur-containing composites of the cathode active material can be strengthened, thereby improving ion and electron conductivity. For example, the cathode active material may be prepared by manufacturing a primary particle (PTC1) containing a sulfur-containing composite and then re-aggregating it together with a first solid electrolyte (SE1) to produce a secondary particle (PTC2), thereby reducing the proportion of fine particles contained within the cathode active material, and accordingly, the D10 of the secondary particle (PTC2) may be 5 μm or more.

[0060] According to one embodiment, D10 of the secondary particle (PTC2) may be 5 µm to 10 µm, D50 of the secondary particle (PTC2) may be 9 µm to 20 µm, and D90 of the secondary particle (PTC2) may be 16 µm to 55 µm. For example, D10 of the secondary particle (PTC2) may be 5 µm to 9 µm. For example, D50 of the secondary particle (PTC2) may be 10 µm to 20 µm. For example, D90 of the secondary particle (PTC2) may be 20 µm to 55 µm, 30 µm to 55 µm, 30 µm to 47 µm, or 30 µm to 40 µm.

[0061] For example, the particle sizes D10, D50, and D90 can be measured using a measuring device that uses a laser diffraction method or a dynamic light scattering method. For example, the D10 particle size is measured using a laser scattering particle size distribution meter (e.g., Horibasa LA-920) and is the value of the median particle size (D10) when accumulated by 10% from the small particle side in volume conversion. For example, the D50 particle size is measured using a laser scattering particle size distribution meter (e.g., Horibasa LA-920) and is the value of the median particle size (D50) when accumulated by 50% from the small particle side in volume conversion. For example, the D90 particle size is measured using a laser scattering particle size distribution meter (e.g., Horibasa LA-920) and is the value of the median particle size (D90) when accumulated by 90% from the small particle side in volume conversion.

[0062] [anode]

[0063] A positive electrode (100) according to one embodiment comprises a positive electrode current collector (110); and a positive electrode active material layer (120) on the positive electrode current collector (110); and the positive electrode active material layer (120) may include the positive electrode active material described above.

[0064] For example, the positive active material layer (120) may include a positive active material comprising a sulfur-based complex having a D10 of 5 μm or more, with a reduced content of fine particles (fine powder). Accordingly, side reactions caused by fine particles are suppressed, and the lifespan characteristics of the all-solid-state battery including the positive active material layer (120) may be improved. In addition, the ion and electron conductivity of the positive active material layer is improved, so the all-solid-state battery including the positive active material layer may have excellent charge / discharge efficiency.

[0065] [Polygon: Positive current collector]

[0066] The positive current collector (110) may provide a reference surface on which the positive active material layer (120) is placed. The positive current collector (110) may include, for example, a plate or foil comprising indium (In), copper (Cu), magnesium (Mg), stainless steel (SUS), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. In another embodiment, the positive current collector (110) may be omitted. Although not illustrated, a carbon layer with a thickness of 0.1 μm to 4 μm may be further disposed between the positive current collector (110) and the positive active material layer (120) to increase the bonding strength between the positive current collector (110) and the positive active material layer (120). The carbon layer may include amorphous carbon, crystalline carbon, etc.

[0067] [Anode: Anode active material layer]

[0068] A positive electrode (100) according to one embodiment comprises a positive electrode current collector (110); and a positive electrode active material layer (120) on the positive electrode current collector (110); and the positive electrode active material layer (120) may include the positive electrode active material described above.

[0069] According to one embodiment, the positive electrode active material layer (120) may include a second solid electrolyte. The second solid electrolyte is configured to be distinct from the first solid electrolyte (SE1), which forms a secondary particle (PTC2) together with the primary particle (PTC1) described above. According to one embodiment, the average particle size (D50) of the second solid electrolyte may be equal to or larger than the particle size of the first solid electrolyte (SE1). By including the positive electrode active material and the second solid electrolyte described above, the positive electrode may have a further reduced internal resistance. Accordingly, the cycle characteristics of an all-solid-state battery equipped with such a positive electrode may be further improved.

[0070] The second solid electrolyte may be a sulfide-based solid electrolyte. Details regarding the sulfide-based solid electrolyte are omitted as the details described in the first solid electrolyte (SE1) can be applied as is. The second solid electrolyte may have the same or different chemical composition as the first solid electrolyte (SE1).

[0071] According to one embodiment, the content of the above-described positive active material may comprise 50 to 99 weight%, 60 to 95 weight%, 70 to 90 weight%, or 75 to 85 weight% with respect to the total weight of the positive active material layer (120). If the content of the positive active material is excessively reduced, the energy density of the all-solid-state battery decreases. If the content of the positive active material is excessively increased, the degradation of the positive can be accelerated due to changes in the volume of the positive during charging and discharging. Consequently, the cycle characteristics of the all-solid-state battery may be degraded.

[0072] According to one embodiment, the content of the second solid electrolyte described above may include 1 to 50 weight%, 5 to 40 weight%, 10 to 30 weight%, or 15 to 25 weight% with respect to the total weight of the positive active material layer (120). If the content of the second solid electrolyte is excessively reduced, the ionic conductivity of the positive active material layer (120) decreases. If the content of the second solid electrolyte is excessively increased, the energy density of the all-solid-state battery decreases. Consequently, the cycle characteristics of the all-solid-state battery may be degraded.

[0073] The positive active material layer (120) may further include a conductive material. The conductive material may be, for example, a carbon-based conductive material, a metal-based conductive material, or a combination thereof. The carbon-based conductive material may be, for example, graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or a combination thereof, but is not limited to these, and any material used as a carbon-based conductive material in the relevant technical field is possible. The metal-based conductive material may be metal powder, metal fiber, or a combination thereof, but is not limited to these, and any material used as a metal-based conductive material in the relevant technical field is possible. The content of the conductive material included in the positive active material layer (120) may be, for example, 1 wt% to 30 wt%, 1 wt% to 20 wt%, or 1 wt% to 10 wt% of the total weight of the positive active material layer (120).

[0074] The positive active material layer (120) includes a carbon-based material, and the carbon-based material may be placed only in the positive active material. The positive active material layer (120) may not additionally include a separate carbon-based material in addition to the positive active material equipped with the carbon-based material. By not including a separate carbon-based material in the positive active material layer (120), the energy density of the positive and secondary batteries can be improved and the manufacturing process can be simplified.

[0075] The positive active material layer (120) may further include a binder. The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited to these, and any binder used in the relevant technical field may be used. The binder content included in the positive active material layer (120) may be, for example, 1 wt% to 10 wt% of the total weight of the positive active material layer (120). The binder may be omitted.

[0076] The positive active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids in addition to the positive active material, solid electrolyte, binder, and conductive material described above.

[0077] The filler, coating agent, dispersant, ion-conducting auxiliary agent, etc. that the positive active material layer (120) may include can be any known material generally used in the electrodes of all-solid-state secondary batteries.

[0078] [cathode]

[0079] A negative electrode (200) according to one embodiment may include a negative electrode current collector (210). In a negative electrode (200) according to one embodiment, lithium metal and / or a lithium alloy may be deposited on the negative electrode current collector (210) by charging. In this case, the lithium metal and / or lithium alloy may act as a lithium reservoir. That is, the all-solid-state battery according to one embodiment may be a lithium metal battery.

[0080] The negative current collector (210) may provide a reference surface on which a lithium metal layer (230) or a negative coating layer (220) is disposed. The negative current collector (210) may include, for example, a material that does not react with lithium, that is, does not form any alloys or compounds with lithium. The material constituting the negative current collector (210) may include at least one metal selected from the group consisting of, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative current collector (210) may be 1 to 20 μm, for example 5 to 15 μm, for example 7 to 10 μm.

[0081] The negative current collector (210) may be composed of one of the metals described above, or may include an alloy of two or more metals or a coating material. The negative current collector (210) is, for example, in the form of a plate or foil. In another embodiment, the negative current collector (210) may be omitted.

[0082] A solid-state battery according to one embodiment may further include a negative coating layer (220) on a negative current collector (210). The negative coating layer (220) may be configured to allow lithium metal to grow between the negative current collector (210) and the negative coating layer (220) and / or within the negative coating layer (220) during charging of the solid-state battery. The negative coating layer (220) may serve as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites. The negative coating layer (220) may include, for example, a metal-carbon composite.

[0083] The metal-carbon composite included in the cathode coating layer (220) is a cathode material capable of forming an alloy or compound with, for example, lithium. The metal-carbon composite has, for example, a particle form. The average particle size of the metal-carbon composite having a particle form is, for example, 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 300 nm or less, or 100 nm or less. The average particle size of the metal-carbon composite having a particle form is, for example, 10 nm to 4 μm, 10 nm to 3 μm, 10 nm to 2 μm, 10 nm to 1 μm, or 10 nm to 500 nm, 10 nm to 300 nm, or 10 nm to 100 nm. By having the average particle size of the metal-carbon composite within this range, the reversible absorption and / or desorption of lithium during charging and discharging may be more facilitated. The average particle size of the metal-carbon composite is, for example, the median diameter (D50) measured using a laser particle size distribution meter.

[0084] A metal-carbon composite may include, for example, metal particles and a carbonaceous material. The metal particles and the carbonaceous material may each have a particle form, for example. A metal-carbon composite may be, for example, a simple mixture of metal particles and a carbonaceous material. The metal particles within the metal-carbon composite may include at least one metal or metalloid selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). However, this is not limited thereto, and any metal or metalloid used in the art to form an alloy or compound with lithium is acceptable. The carbonaceous material within the metal-carbon composite may include, for example, amorphous carbon, crystalline carbon, porous carbon, or a combination thereof. The carbonaceous material within the metal-carbon composite may be amorphous carbon. The carbonaceous material within the metal-carbon composite may include, for example, carbon black, acetylene black, furnace black, Kettjen black, graphene, or a combination thereof. Amorphous carbon may be carbon that does not have crystallinity or has very low crystallinity. The carbonaceous material within the metal-carbon composite may be, for example, porous carbon. The pore volume contained in the porous carbon may be, for example, 0.1 cc / g to 10.0 cc / g, 0.5 cc / g to 5 cc / g, or 0.1 cc / g to 1 cc / g. The average pore diameter contained in the porous carbon may be, for example, 1 nm to 50 nm, 1 nm to 30 nm, or 1 nm to 10 nm. The BET specific surface area of ​​the porous carbon is, for example, 100 m² 2 / g to 3,000 m 2It can be / g. The BET specific surface area of ​​porous carbon can be measured, for example, according to ISO 9277:2022.

[0085] The mixing ratio of metal particles and carbon-based material included in the cathode coating layer (220) can be, for example, 1:10 to 2:1, 1:5 to 1:1, or 1:4 to 1:2 by weight.

[0086] The metal-carbon composite may be, for example, a composite of metal particles and a carbon-based material. The carbon-based material may be, for example, a carbon-based support. The metal-carbon composite may include, for example, a carbon-based support and metal particles supported on the carbon-based support. By having such a structure, the localization of metal particles within the cathode coating layer (220) is prevented and a uniform distribution can be obtained. Consequently, the cycle characteristics of the all-solid-state battery including the cathode coating layer (220) can be further improved.

[0087] Metal particles supported on a carbon-based support may include, for example, a metal, a metal oxide, a composite of a metal and a metal oxide, or a combination thereof. The metal may include, for example, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), tellurium (Te), and zinc (Zn). The metal oxide may include, for example, gold (Au) oxide, platinum (Pt) oxide, palladium (Pd) oxide, silicon (Si) oxide, silver (Ag) oxide, aluminum (Al) oxide, bismuth (Bi) oxide, tin (Sn) oxide, tellurium (Te) oxide, and zinc (Zn) oxide. The metal oxide may include, for example, Au x O y (0 <x≤2, 0<y≤3), Pt x O y (0 <x≤1, 0<y≤2), Pd x O y (0 <x≤1, 0<y≤1), Si x Oy (0 <x≤1, 0<y≤2), Ag x The y (0 <x≤2, 0<y≤1), Al x The y (0 <x≤2, 0<y≤3), Bi x The y (0 <x≤2, 0<y≤3), Sn x The y (0 <x≤1, 0<y≤2), Te x The y (0 <x≤1,0<y≤3), Zn x The y (0 <x≤1, 0<y≤1) 또는 이들의 조합을 포함할 수 있다. 금속과 금속 산화물의 복합체는 예를 들어 Au와 Au x The y (0 <x≤2, 0<y≤3)의 복합체, Pt와 Pt x The y (0 <x≤1, 0<y≤2)의 복합체, Pd와 Pd x The y (0 <x≤1, 0<y≤1)의 복합체, Si와 Si x The y (0 <x≤1, 0<y≤2)의 복합체, Ag 와 Ag x The y (0 <x≤2, 0<y≤1)의 복합체, Al과 Al x The y (0 <x≤2, 0<y≤3)의 복합체, Bi와 Bi x The y (0 <x≤2, 0<y≤3)의 복합체, Sn과 Sn x The y (0 <x≤1, 0<y≤2)의 복합체, Te과 Te x The y (0 <x≤1, 0<y≤3), Zn과 Zn x The y (0 <x≤1, 0<y≤1)의 복합체, 또는 이들의 조합을 포함할 수 있다.

[0088] A carbon-based support is, for example, amorphous carbon. Amorphous carbon is, for example, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, activated carbon, carbon nanofiber (CNF), carbon nanotube (CNT), etc., but is not necessarily limited to these, and any carbon classified as amorphous carbon in the relevant technical field is acceptable. Amorphous carbon is carbon that does not have crystallinity or has very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon.

[0089] The binder included in the cathode coating layer (220) may be, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited to these and any binder used in the relevant technical field is possible. The binder may be composed of a single binder or a plurality of different binders.

[0090] The cathode coating layer (220) may further include other additives in addition to the metal-carbon composite. The cathode coating layer (220) may further include at least one additive selected from the group consisting of, for example, fillers, coating agents, dispersants, and ion-conducting aids.

[0091] The cathode coating layer (220) may further include a solid electrolyte. The solid electrolyte may be a material selected from, for example, a solid electrolyte included in a solid electrolyte separator. The solid electrolyte included in the cathode coating layer (220) may act as a reaction site where the formation of lithium metal begins within the cathode coating layer (220), act as a space where the formed lithium metal is stored, or act as a path for transporting lithium ions. The solid electrolyte may be omitted.

[0092] FIG. 3 is a cross-sectional view of an all-solid-state battery according to an exemplary embodiment. Referring to FIG. 3, a negative electrode (200) according to another embodiment may further include a lithium metal layer (230) disposed between a negative electrode current collector (210) and a negative electrode coating layer (220). The lithium metal layer (230) may be a configuration formed by charging the all-solid-state battery. Although not shown in the drawing, the all-solid-state battery may further include a lithium metal layer (230) disposed inside the negative electrode coating layer (220) by charging.

[0093] The lithium metal layer (230) may include lithium or a lithium alloy. Since the lithium metal layer (230) is a metal layer containing lithium, it may function as, for example, a lithium reservoir. The lithium alloy may be, for example, Li-Al alloy, Li-Sn alloy, Li-In alloy, Li-Ag alloy, Li-Au alloy, Li-Zn alloy, Li-Ge alloy, Li-Si alloy, etc., but is not limited to these; any alloy used as a lithium alloy in the relevant technical field may be possible. The lithium metal layer (230) may be composed of one of these alloys or lithium, or may be composed of various types of alloys. The lithium metal layer (230) may be, for example, a plated layer. The lithium metal layer (230) may be, for example, deposited between the negative electrode coating layer (220) and the negative electrode current collector (210) during the charging process of an all-solid-state battery.

[0094] In another embodiment, the lithium metal layer (230) within the negative electrode may be provided, for example, between the negative electrode current collector (210) and the negative electrode coating layer (220) before assembly of the all-solid-state battery. When the lithium metal layer (230) is placed between the negative electrode current collector (210) and the negative electrode coating layer (220) before assembly of the all-solid-state battery, the lithium metal layer (230) acts as a lithium reservoir because it is a metal layer containing lithium. For example, a lithium foil may be placed between the negative electrode current collector (210) and the negative electrode coating layer (220) before assembly of the all-solid-state battery.

[0095] When a lithium metal layer (230) is precipitated by charging after assembly of the all-solid-state battery, the energy density of the all-solid-state battery can be increased because the lithium metal layer (230) is not included during assembly of the all-solid-state battery. When charging the all-solid-state battery, it can be charged beyond the charging capacity of the negative electrode coating layer (220). That is, the negative electrode coating layer (220) can be overcharged. At the beginning of charging, lithium can be absorbed in the negative electrode coating layer (220). If charging is performed beyond the capacity of the negative electrode coating layer (220), lithium can be precipitated, for example, between the negative electrode coating layer (220) and the negative electrode current collector (210). A lithium metal layer (230) can be formed by the precipitated lithium.

[0096] The lithium metal layer (230) can be composed mainly of lithium (i.e., metallic lithium). During discharge, the lithium in the lithium metal layer (230) can be ionized and move to the positive electrode (100). In other words, lithium can be used as a negative electrode active material in a solid-state battery. In addition, since the negative electrode coating layer (220) covers the lithium metal layer (230), the negative electrode coating layer (220) can protect the lithium metal layer (230) and simultaneously suppress the precipitation growth of lithium dendrites. Therefore, the negative electrode coating layer (220) can suppress short circuits and capacity degradation of the solid-state battery and improve the cycle characteristics of the solid-state battery.

[0097] When a lithium metal layer (230) is formed by charging after assembly of the all-solid-state battery, the negative electrode, i.e., the negative electrode current collector (210) and the negative electrode coating layer (220) and the region between them may be a Li-free region that does not contain lithium (Li) in the initial state or after complete discharge of the all-solid-state battery.

[0098] [Electrolyte layer]

[0099] Referring to FIG. 2, the electrolyte layer (300) may include an electrolyte disposed between the anode (100) and the cathode (200). The electrolyte may include, for example, a solid electrolyte, a gel electrolyte, or a combination thereof.

[0100] Solid electrolytes may include, for example, sulfide-based solid electrolytes, oxide-based solid electrolytes, polymeric solid electrolytes, or combinations thereof.

[0101] Since the details described above for the first solid electrolyte (SE1) and the second solid electrolyte can be applied directly to the sulfide-based solid electrolyte, the explanation of the overlapping parts will be omitted.

[0102] Oxide-based solid electrolytes are, for example, Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Aly Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<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), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, 0≤x≤10), or a combination thereof. Oxide-based solid electrolytes are produced, for example, by sintering.

[0103] Oxide-based solid electrolytes are, for example, Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 (M-doped LLZO, M=Ga, W, Nb, Ta, or Al(0 <a<2, 0≤x≤10) 중에서 선택된 가넷계(Garnet-type) 고체 전해질이다.

[0104] The polymer solid electrolyte may, for example, comprise a mixture of a lithium salt and a polymer, or comprise a polymer having ion-conducting functional groups. The polymer solid electrolyte may, for example, be a polymer electrolyte in a solid state at 25°C and 1 atm. The polymer solid electrolyte may, for example, not contain a liquid.The polymeric solid electrolyte comprises a polymer, wherein the polymer is, for example, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), poly(styrene-b-ethylene oxide) block copolymer (PS-PEO), poly(styrene-butadiene), poly(styrene-isoprene-styrene), poly(styrene-b-divinylbenzene) block copolymer, poly(styrene-ethylene oxide-styrene) block copolymer, polystyrene sulfonate (PSS), polyvinyl fluoride (PVF), poly(methylmethacrylate) (PMMA), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), Polyaniline, Polyacetylene, Nafion, Aquivion, Flemion, Gore, Aciplex, Morgane ADP, Sulfonated poly(ether ether ketone) (SPEEK), Sulfonated poly(arylene ether ketone ketone sulfone) (SPAEKKS), Sulfonated poly(arylether ketone) (SPAEK), Poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI), Poly(styrene sulfonate) (PSS), Lithium 9,10-Diphenylanthracene-2-sulfonate (lithium 9,10-diphenylanthracene-2-sulfonate, DPASLi. +It may be ) or a combination thereof, but is not limited thereto, and any that are used in polymer electrolytes in the relevant technical field are permitted. Any lithium salt that can be used as a lithium salt in the relevant technical field is permitted. Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F2 x+1 SO2)(C y F 2y+1 The polymer may be SO2)(x and y are each 1 to 20), LiCl, LiI, or a mixture thereof. The polymer included in the polymer solid electrolyte may be, for example, a compound containing 10 or more, 20 or more, 50 or more, or 100 or more repeating units. The weight-average molecular weight of the polymer included in the polymer solid electrolyte may be, for example, 1,000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more, or 1,000,000 Dalton or more.

[0105] Gel electrolytes are, for example, polymeric gel electrolytes. Gel electrolytes can have a gel state without, for example, containing polymers.

[0106] Polymer gel electrolytes may, for example, comprise a liquid electrolyte and a polymer, or comprise an organic solvent and a polymer having ion-conducting functional groups. Polymer gel electrolytes may, for example, be polymer electrolytes in a gel state at 25°C and 1 atm. Polymer gel electrolytes may, for example, have a gel state without containing a liquid. The liquid electrolyte used in the polymer gel electrolyte may be, for example, an ionic liquid, a mixture of a lithium salt and an organic solvent; a mixture of a lithium salt and an organic solvent; a mixture of an ionic liquid and an organic solvent; or a mixture of a lithium salt, an ionic liquid, and an organic solvent. The polymer used in the polymer gel electrolyte may be selected from the polymers used in solid polymer electrolytes. The organic solvent may be selected from the organic solvents used in liquid electrolytes. The lithium salt may be selected from the lithium salts used in solid polymer electrolytes. An ionic liquid refers to a salt or a room-temperature molten salt that has a melting point below room temperature, consists solely of ions, and is in a liquid state at room temperature. The ionic liquid comprises, for example, a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4 - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N -It may include one or more compounds selected from those containing one or more anions selected from among. The polymer solid electrolyte may form a polymer gel electrolyte by impregnating it into a liquid electrolyte in a secondary battery, for example. The polymer gel electrolyte may further include inorganic particles. The polymer included in the polymer gel electrolyte may be a compound containing, for example, 10 or more, 20 or more, 50 or more, or 100 or more repeating units. The weight-average molecular weight of the polymer included in the polymer gel electrolyte may be, for example, 500 Dalton or more, 1000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more, or 1,000,000 Dalton or more.

[0107] The electrolyte layer (300) may include, for example, a binder. The binder included in the electrolyte layer (300) may be, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited to these and any binder used in the relevant technical field is possible. The binder of the electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) and the negative electrode coating layer (220). The binder may be omitted.

[0108] The binder content included in the electrolyte layer (300) is 0.1 to 10 wt%, 0.1 to 5 wt%, 0.1 to 3 wt%, 0.1 to 1 wt%, 0 to 0.5 wt%, or 0 to 0.1 wt% based on the total weight of the electrolyte layer (300).

[0109] [Method for manufacturing positive electrode active material]

[0110] To manufacture a positive electrode active material, a composition containing a sulfur-based material is ball-milled to produce primary particles containing a sulfur-containing complex. For example, the sulfur-based material may be a composition containing Li2S.

[0111] When primary particles are prepared in this manner, secondary particles are prepared by granulating the primary particles together with a solid electrolyte to produce a positive electrode active material. By granulating the primary particles together with a solid electrolyte to produce secondary particles, the D10 of the secondary particles may be 5㎛ or more.

[0112] According to one embodiment, a primary particle containing the sulfur-containing composite can be produced by first ball-milling a composition containing Li2S and a metal halide salt to form a first composition, injecting a carbon-based conductive material into the first composition, and then second-ball-milling to produce a primary particle containing the sulfur-containing composite.

[0113] For a description of the above sulfur-containing composite, sulfur-based material, metal halide salt, carbon-based conductive material, primary particle, and secondary particle, refer to the description above.

[0114] According to one embodiment, the first ball milling and the second ball milling may be performed independently of each other at 100 to 1000 rpm for 1 to 20 hours. For example, the first ball milling and the second ball milling may be performed independently of each other at 200 to 800 rpm, 300 to 700 rpm, or 400 to 600 rpm. For example, the first ball milling and the second ball milling may be performed independently of each other for 1 to 16 hours, 2 to 12 hours, or 3 to 10 hours.

[0115] The manufacture of the above secondary particles can be carried out by granulating the above primary particles and solid electrolyte. For example, the granulation can be carried out by introducing the above primary particles and solid electrolyte into a mixer such as Hosokawa Micron’s NOBILTA MINI or NARA’s Hybridization system.

[0116] For example, the above granulation is performed by introducing the primary particles and solid electrolyte into the NOBILTA MINI container of Hosokawa Micron, and the amount of the primary particles and solid electrolyte introduced can be 20 to 80 volume%, 30 to 70 volume%, 30 to 60 volume%, or 30 to 50 volume% with respect to the total volume of the container.

[0117] For example, the above-mentioned granulation may be performed for 2 to 25 minutes, 3 to 20 minutes, 5 to 20 minutes, 7 to 20 minutes, or for a period of time. For example, the above-mentioned granulation may be performed at 1,000 to 9,000 rpm, 2,000 to 8,000 rpm, 3,000 to 7,000 rpm, or 4,000 to 6,000 rpm.

[0118]

[0119] The creative idea is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the creative idea and do not limit the scope of the creative idea to these examples alone.

[0120]

[0121] (Manufacturing of cathode active material)

[0122] Preparation Example 1: Li2S-LiI-AlI3-CNF + SE(LPSCl), Step 3, Secondary particle D10 = 6.2㎛

[0123] (Stage 1)

[0124] Li2S, LiI, and AlI3 were mixed in a weight ratio of 40:5:15. The mixture was mechanically milled using a ball mill to prepare a Li2S-LiI-AlI3 composite. The milling conditions were 25°C at 450 rpm for 10 hours. The milling energy applied to the sample during milling was 28 G.

[0125] (Stage 2)

[0126] The Li2S-LiI-AlI3 composite and carbon nanofiber (CNF) were mixed in a weight ratio of 60:10. The mixture was mechanically milled using a ball mill to prepare the Li2S-LiI-AlI3-CNF composite. The milling conditions were 25°C at 450 rpm for 10 hours. The milling energy applied to the sample during milling was 28 G.

[0127] (Stage 3)

[0128] A Li2S-LiI-AlI3-CNF composite and a solid electrolyte (LPSCl, Li6PS5Cl) were mixed in a weight ratio of 4:1 and placed into a container of Hosokawa Micron’s NOBILTA MINI. The amount added was 40% by volume relative to the total volume of the container. Subsequently, secondary particles were prepared by operating at 5000 rpm for 10 minutes. The secondary particles of the Li2S-LiI-AlI3-CNF and LPSCl composite were used as the cathode active material.

[0129] D10 of the above Li2S-LiI-AlI3-CNF composite secondary particles is the value of the median particle size (D10) when accumulated by 10% from the small particle side in volume conversion, measured using a laser scattering particle size distribution meter (Horibasa LA-920). The D10 of the above Li2S-LiI-AlI3-CNF composite secondary particles was 6.2 μm. D50 of the above Li2S-LiI-AlI3-CNF composite secondary particles is the value of the median particle size (D50) when accumulated by 50% from the small particle side in volume conversion, measured using a laser scattering particle size distribution meter (Horibasa LA-920). The D90 of the above Li2S-LiI-AlI3-CNF composite secondary particle is measured using a laser scattering particle size distribution meter (Horibasa LA-920) and is the value of the median particle size (D90) when 90% is accumulated from the small particle side in volume conversion.

[0130] Preparation Example 2: Li2S-LiI-AlI3-CNF + SE(LPSCl), Step 3, Secondary particle D10 = 8.8㎛

[0131] A positive electrode active material was prepared in the same manner as in Preparation Example 1, except that secondary particles were prepared by operating at 5000 rpm for 5 minutes in the third step, and the D10 of the prepared secondary particles was 8.8 μm.

[0132] Preparation Example 3: Li2S-LiI-AlI3-CNF + SE(LPSCl), Step 3, Secondary particle D10 = 8.1㎛

[0133] In the third step, 5 wt% of water-removed xylene solvent was added to Li2S-LiI-AlI3-CNF and LPSCl powders using a thinky mixer, and then the mixture was added to a NOBILTA MINI container for secondary particle formation. A cathode active material was prepared in the same manner as in Preparation Example 1, except that xylene was added as an additive during secondary particle formation, and the D10 of the secondary particles produced was 8.1 μm.

[0134] Comparative Preparation Example 1: Li2S-LiI-AlI3-CNF, 3 steps, secondary particle D10 = 3.16 μm

[0135] A positive electrode active material was prepared in the same manner as in Preparation Example 1, except that in the third step, a solid electrolyte was not added, and secondary particles were prepared by operating at 9000 rpm for 10 minutes, and the particle size conditions of the secondary particles were adjusted so that the D10 of the prepared secondary particles was 3.16 μm.

[0136]

[0137] (Evaluation Example 1)

[0138] D10, D50, and D90 of the cathode active materials according to Preparation Examples 1 to 3 and Comparative Preparation Example 1 were measured using a particle size analyzer. Particle sizes were measured, for example, using a laser scattering particle size analyzer (Horibasa LA-920). D10 was defined as the median particle size value when accumulated at 10% from the small particle side in terms of volume, D50 as the median particle size value when accumulated at 50% from the small particle side in terms of volume, and D90 as the median particle size value when accumulated at 90% from the small particle side in terms of volume. Dehydrated xylene was used as the solvent for the measurement. The measurement results are listed in Table 1 below.

[0139] D10 D50 D90 Manufacturing Example 16.211.235.5 Manufacturing Example 28.817.242.1 Manufacturing Example 38.114.630 Comparative Manufacturing Example 13.167.820.1

[0140] (Evaluation Example 2) The electron conductivity and ionic conductivity of the positive electrode active materials according to Preparation Examples 1 to 3 and Comparative Preparation Example 1 were measured. The electron conductivity and ionic conductivity were measured by electrochemical impedance spectroscopy (Els). The measurement results are listed in Table 2 below.

[0141] Electron Conductivity (mS / cm) Ionic Conductivity (mS / cm) Preparation Example 18.66 0.0075 Preparation Example 28.15 0.0072 Preparation Example 38.52 0.0065 Comparative Preparation Example 15.77 0.0045

[0142] (Manufacture of positive electrode and secondary battery) Example 1

[0143] (Anode manufacturing)

[0144] As the positive electrode active material, secondary particles of a composite of Li2S-LiI-AlI3-CNF and LPSCl prepared in Preparation Example 1 were prepared. As the solid electrolyte, Li6PS5Cl, an argyrodite-type crystal (D50=3.0 μm, crystalline), was prepared. As the binder, PTFE was prepared. These materials were mixed in a weight ratio of positive electrode active material : solid electrolyte : binder = 80 : 20 : 1.2 to prepare a positive electrode composite. The positive electrode composite was obtained by dry mixing using a blender.

[0145] An anode was prepared by placing the anode composite on one side of an anode current collector made of aluminum foil coated with carbon on one side and plate pressing at a pressure of 200 MPa for 10 minutes. The thickness of the anode was approximately 120 μm. The thickness of the anode active material layer was approximately 100 μm, and the thickness of the carbon-coated aluminum foil was approximately 20 μm. The area of ​​the anode active material layer and the anode current collector were the same.

[0146] (Cathode manufacturing)

[0147] A SUS foil with a thickness of 10 μm was prepared as a cathode current collector. As a metal-carbon composite, carbon black (CB) with a primary particle size of about 30 nm and silver (Ag) particles with an average particle diameter of about 60 nm were prepared.

[0148] 4 g of a mixed powder, prepared by mixing carbon black (CB) and silver (Ag) particles in a weight ratio of 3:1, was placed in a container, and 4 g of an NMP solution containing 7 wt% of a PVDF binder (Kureha # 9300) was added to prepare a mixed solution. A slurry was prepared by stirring the mixed solution while gradually adding NMP to it. The prepared slurry was applied to a SUS sheet using a bar coater, dried in air at 80°C for 10 minutes, and then vacuum dried at 40°C for 10 hours to prepare a laminate. The prepared laminate was cold-roll-pressed to flatten the surface, thereby preparing a cathode having a cathode coating layer / cathode current collector structure. The thickness of the cathode coating layer was approximately 15 μm. The surface area of ​​the cathode coating layer and the cathode current collector were the same.

[0149] (Preparation of solid electrolyte layer)

[0150] A mixture was prepared by adding 1.5 parts by weight of an acrylic binder to 98.5 parts by weight of an argyrodite-type crystal Li6PS5Cl solid electrolyte (D50=3.0 mm, crystalline). A slurry was prepared by stirring while adding octyl acetate to the prepared mixture. The prepared slurry was applied using a bar coater onto a 15 μm thick nonwoven fabric placed on a 75 μm thick PET substrate, and a laminate was prepared by drying in air at 80°C for 10 minutes. A solid electrolyte layer was prepared by vacuum drying the prepared laminate at 80°C for 2 hours.

[0151] (Manufacturing of all-solid-state batteries)

[0152] Referring to Fig. 2, a solid electrolyte layer was placed on the cathode such that a cathode coating layer contacted the solid electrolyte layer, and an anode was placed on the solid electrolyte layer. The prepared laminate was subjected to plate pressing at 85°C and a pressure of 500 MPa for 30 minutes. This pressurization process sintered the solid electrolyte layer, thereby improving battery characteristics. The thickness of the sintered solid electrolyte layer was approximately 45 μm. The density of the Li6PS5Cl solid electrolyte, an argyrodite-type crystal contained in the sintered solid electrolyte layer, was 1.6 g / cc. The area of ​​the solid electrolyte layer was equal to the area of ​​the cathode.

[0153] An all-solid-state secondary battery was manufactured by placing a pressurized laminate into a pouch and vacuum sealing it. Parts of the positive and negative current collectors were extended outside the sealed battery to be used as the positive and negative terminals.

[0154] Examples 2 to 3

[0155] A positive electrode and an all-solid-state battery were prepared in the same manner as in Example 1, except that the positive electrode active materials prepared in Preparation Examples 2 and 3 were used, respectively.

[0156] Comparative Example 1

[0157] A positive electrode and an all-solid-state battery were prepared in the same manner as in Example 1, except that the positive electrode active material prepared in Comparative Preparation Example 1 was used.

[0158] Evaluation Example 3: Charge / Discharge Test

[0159] The charge and discharge characteristics of the all-solid-state batteries of Examples 1 to 3 and Comparative Example 1 were evaluated by the following charge and discharge test.

[0160] The charge / discharge test was performed by placing the all-solid-state secondary battery in a constant temperature bath at 45°C.

[0161] The first cycle involved charging at a constant current of 0.1 C for 12.5 hours until the battery voltage reached 2.5 V to 2.8 V. Subsequently, discharging was performed at a constant current of 0.1 C for 12.5 hours until the battery voltage reached 0.3 V.

[0162] The discharge capacity of the first cycle was set as the standard capacity. The standard capacity is expressed as the specific capacity of Li2S in Table 3 below.

[0163] After the second cycle, charging and discharging were performed for up to 150 cycles under the same conditions as the first cycle. The measurement results are shown in Table 2 below. The initial efficiency is expressed by the following Equation 1.

[0164] <Mathematical Formula 1>

[0165] Initial efficiency [%] = [1st cycle discharge capacity / 1st cycle charge capacity] × 100

[0166] The number of cycles refers to the number of cycles required for the discharge capacity to decrease to 80% of the standard capacity after the second cycle. It was considered that the life characteristics were superior as the number of cycles increased.

[0167] Specific Capacity [mAh / g] Initial Efficiency [%] Number of Cycles [times] Example 1 (D10 = 6.2 µm) 819 85.695 Example 2 (D10 = 8.8 µm) 800 85.088 Example 3 (D10 = 8.1 µm) 779 84.287 Comparative Example 1 (D10 = 3.16 µm) 749 83.765

[0168] As shown in Table 3, the all-solid-state batteries according to Examples 1 to 3 exhibited improved discharge capacity, initial efficiency, and lifespan characteristics compared to the all-solid-state battery of Comparative Example 1. Although exemplary embodiments have been described in detail above with reference to the attached drawings, the present creative concept is not limited to such examples. It is obvious that a person skilled in the art to which the present creative concept belongs can derive various modified or altered examples within the scope of the technical concept described in the patent claims, and these also naturally fall within the technical scope of the present creative concept.

Claims

1. Primary particles comprising a sulfur-based complex; and It comprises secondary particles including the primary particles and the first solid electrolyte; The above sulfur-containing composite is a composite of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, and The above sulfur-based materials are S8 and Li2S n Includes at least one of (1 ≤ n ≤ 8, n is an integer), and The above metal halide salts include alkali metal salts and boron group metal salts, and A positive active material in which the D10 of the above secondary particles is 5㎛ or larger.

2. In Paragraph 1, The D10 of the above secondary particle is 5㎛ to 10㎛, and The D50 of the above secondary particles is 10㎛ to 20㎛, and A positive active material having a D90 of the above secondary particles of 20㎛ to 60㎛.

3. In Paragraph 1, A positive electrode active material having a molar ratio of the above sulfur-based material and the above metal halide salt of 50:50 to 95:

5.

4. In Paragraph 1, The above sulfur-based material includes Li2S, and The above sulfur-containing composite is a positive active material comprising a composite of the above Li2S and the above metal halide salt.

5. In Paragraph 1, The above alkali metal salt is a positive active material comprising LiF, LiCl, LiBr, LiI, or a combination thereof.

6. In Paragraph 1, The above boron group metal salt is a positive active material comprising AlF3, AlCl3, AlBr3, AlI3, GaF3, GaCl3, GaBr3, GaI3, InF3, InCl3, lnBr3, lnI3, TlF3, TlCl3, TlBr3, TlI3, or a combination thereof.

7. In Paragraph 1, 상기 황 함유 복합체는 Li2S-LiF-CNT, Li2S-LiCl-CNT, Li2S-LiBr-CNT, Li2S-LiI-CNT, Li2S-LiF-CNF, Li2S-LiCl-CNF, Li2S-LiBr-CNF, Li2S-LiI-CNF, Li2S-LiF-AlF3-CNT, Li2S-LiF-AlCl3-CNT, Li2S-LiF-AlBr3-CNT, Li2S-LiF-AlI3-CNT, Li2S-LiF-GaF3-CNT, Li2S-LiF-GaCl3-CNT, Li2S-LiF-GaBr3-CNT, Li2S-LiF-GaI3-CNT, Li2S-LiF-InF3-CNT, Li2S-LiF-InCl3-CNT, Li2S-LiF-InBr3-CNT, Li2S-LiF-InI3-CNT, Li2S-LiF-TlF3-CNT, Li2S-LiF-TlCl3-CNT, Li2S-LiF-TlBr3-CNT, Li2S-LiF-TlI3-CNT, Li2S-LiCl-AlF3-CNT, Li2S-LiCl-AlCl3-CNT, Li2S-LiCl-AlBr3-CNT, Li2S-LiCl-AlI3-CNT, Li2S-LiCl-GaF3-CNT, Li2S-LiCl-GaCl3-CNT, Li2S-LiCl-GaBr3-CNT, Li2S-LiCl-GaI3-CNT, Li2S-LiCl-InF3-CNT, Li2S-LiCl-InCl3-CNT, Li2S-LiCl-InBr3-CNT, Li2S-LiCl-InI3-CNT, Li2S-LiCl-TlF3-CNT, Li2S-LiCl-TlCl3-CNT, Li2S-LiCl-TlBr3-CNT, Li2S-LiCl-TlI3-CNT, Li2S-LiBr-AlF3-CNT, Li2S-LiBr-AlCl3-CNT, Li2S-LiBr-AlBr3-CNT, Li2S-LiBr-AlI3-CNT, Li2S-LiBr-GaF3-CNT, Li2S-LiBr-GaCl3-CNT, Li2S-LiBr-GaBr3-CNT, Li2S-LiBr-GaI3-CNT, Li2S-LiBr-InF3-CNT, Li2S-LiBr-InCl3-CNT, Li2S-LiBr-InBr3-CNT,Li2S-LiBr-InI3-CNT, Li2S-LiBr-TlF3-CNT, Li2S-LiBr-TlCl3-CNT, Li2S-LiBr-TlBr3-CNT, Li2S-LiBr-TlI3-CNT, Li2S-LiI-AlF3-CNT, Li2S-LiI-AlCl3-CNT, Li2S-LiI-AlBr3-CNT, Li2S-LiI-AlI3-CNT, Li2S-LiI-GaF3-CNT, Li2S-LiI-GaCl3-CNT, Li2S-LiI-GaBr3-CNT, Li2S-LiI-GaI3-CNT, Li2S-LiI-InF3-CNT, Li2S-LiI-InCl3-CNT, Li2S-LiI-InBr3-CNT, Li2S-LiI-InI3-CNT, Li2S-LiI-TlF3-CNT, Li2S-LiI-TlCl3-CNT, Li2S-LiI-TlBr3-CNT, Li2S-LiI-TlI3-CNT, Li2S-LiF-AlF3-CNF, Li2S-LiF-AlCl3-CNF, Li2S-LiF-AlBr3-CNF, Li2S-LiF-AlI3-CNF, Li2S-LiF-GaF3-CNF, Li2S-LiF-GaCl3-CNF, Li2S-LiF-GaBr3-CNF, Li2S-LiF-GaI3-CNF, Li2S-LiF-InF3-CNF, Li2S-LiF-InCl3-CNF, Li2S-LiF-InBr3-CNF, Li2S-LiF-InI3-CNF, Li2S-LiF-TlF3-CNF, Li2S-LiF-TlCl3-CNF, Li2S-LiF-TlBr3-CNF, Li2S-LiF-TlI3-CNF, Li2S-LiCl-AlF3-CNF, Li2S-LiCl-AlCl3-CNF, Li2S-LiCl-AlBr3-CNF, Li2S-LiCl-AlI3-CNF, Li2S-LiCl-GaF3-CNF, Li2S-LiCl-GaCl3-CNF, Li2S-LiCl-GaBr3-CNF, Li2S-LiCl-GaI3-CNF, Li2S-LiCl-InF3-CNF, Li2S-LiCl-InCl3-CNF, Li2S-LiCl-InBr3-CNF, Li2S-LiCl-InI3-CNF, Li2S-LiCl-TlF3-CNF,Li2S-LiCl-TlCl3-CNF, Li2S-LiCl-TlBr3-CNF, Li2S-LiCl-TlI3-CNF, Li2S-LiBr-AlF3-CNF, Li2S-LiBr-AlCl3-CNF, Li2S-LiBr-AlBr3-CNF, Li2S-LiBr-AlI3-CNF, Li2S-LiBr-GaF3-CNF, Li2S-LiBr-GaCl3-CNF, Li2S-LiBr-GaBr3-CNF, Li2S-LiBr-GaI3-CNF, Li2S-LiBr-InF3-CNF, Li2S-LiBr-InCl3-CNF, Li2S-LiBr-InBr3-CNF, Li2S-LiBr-InI3-CNF, Li2S-LiBr-TlF3-CNF, Li2S-LiBr-TlCl3-CNF, Li2S-LiBr-TlBr3-CNF, Li2S-LiBr-TlI3-CNF, Li2S-LiI-AlF3-CNF, Li2S-LiI-AlCl3-CNF, Li2S-LiI-AlBr3-CNF, Li2S-LiI-AlI3-CNF, Li2S-LiI-GaF3-CNF, Li2S-LiI-GaCl3-CNF, Li2S-LiI-GaBr3-CNF, Li2S-LiI-GaI3-CNF, Li2S-LiI-InF3-CNF, Li2S-LiI-InCl3-CNF, Li2S-LiI-InBr3-CNF, Li2S-LiI-InI3-CNF, Li2S-LiI-TlF3-CNF, Li2S-LiI-TlCl3-CNF, Li2S-LiI-TlBr3-CNF, Li2S-LiI-TlI3-CNF 또는 이들의 조합을 포함, 양극 활물질., 8. In Paragraph 1, The above carbon-based conductive material comprises a fibrous carbon-based conductive material selected from the group consisting of carbon nanotubes (CNT), carbon nanofibers (CNF), carbon nanobelts, carbon nanorods, and graphene. A positive active material having a content of the carbon-based conductive material of 1 to 30 wt% of the total weight of the sulfur-containing composite.

9. In Paragraph 1, The above first solid electrolyte is a sulfide-based solid electrolyte, and The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX, where X is a halogen element, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n , m, n are positive numbers, Z is one of Ge, Zn, or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, In, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x One or more positive active materials selected from (0≤x≤2).

10. A positive electrode comprising a positive current collector and a positive active material layer on the positive current collector; cathode; and It includes an electrolyte layer disposed between the anode and the cathode; A secondary battery comprising a positive active material layer according to claim 1.

11. In Paragraph 10, A secondary battery in which the content of the positive active material is 50 to 99 weight% with respect to the total weight of the positive active material layer.

12. In Paragraph 10, A secondary battery in which the positive active material layer further comprises a second solid electrolyte.

13. In Paragraph 12, The above second solid electrolyte is a sulfide-based solid electrolyte, and The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX, where X is a halogen element, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n , m, n are positive numbers, Z is one of Ge, Zn, or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, In, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x One or more secondary batteries selected from (0≤x≤2).

14. In Paragraph 13, The above sulfide-based solid electrolyte includes an argyrodite-type solid electrolyte, and The above argyrodite-type solid electrolyte comprises one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I, in a secondary battery.

15. In Paragraph 10, A secondary battery in which the positive active material layer further comprises a binder.

16. In Paragraph 10, The above electrolyte layer comprises a solid electrolyte, in a secondary battery.

17. In Paragraph 10, A secondary battery comprising a negative electrode, a negative current collector, and a negative coating layer on the negative current collector.

18. In Paragraph 17, A secondary battery comprising a metal-carbon composite in the above-mentioned negative electrode coating layer.

19. Ball-milling a composition containing a sulfur-based material to produce primary particles containing a sulfur-containing complex; and The method includes manufacturing secondary particles by granulating the primary particles together with a solid electrolyte; The above sulfur-containing composite is a composite of a sulfur-based material, a metal halide salt, and a carbon-based conductive material, and The above sulfur-based materials are S8 and Li2S n Includes at least one of (1 ≤ n ≤ 8, n is an integer), and The above metal halide salts include alkali metal salts and boron group metal salts, and A method for manufacturing a positive electrode active material, wherein the D10 of the secondary particles is 5㎛ or larger.

20. In Paragraph 19, Manufacturing primary particles containing the above sulfur-containing complex is, Forming a first composition by first ball milling a composition comprising Li2S and a metal halide salt; and A method for manufacturing an anode active material, comprising injecting a carbon-based conductive material into a first composition and then performing secondary ball milling to produce primary particles containing a sulfur-containing composite.

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