Method for preparing anode slurry for all-solid-state battery, anode for all-solid-state battery prepared using same, and all-solid-state battery comprising same

Abstract

The present invention relates to a method for preparing an anode slurry for an all-solid-state battery, an anode for an all-solid-state battery, prepared using same, and an all-solid-state battery comprising same and, more specifically, to a method for preparing an anode slurry for an all-solid-state battery, an anode for an all-solid-state battery, prepared using same, and an all-solid-state battery comprising same, the method comprising: mixing an anode material and a first thickener including a first binder and a first solvent to form a first mixture; dispersing the first mixture to form a dispersion; mixing the dispersion with a second thickener including a second binder and a second solvent to form a second mixture; and mixing the second mixture with a polymer, wherein the first thickener is added in a first addition amount, the second thickener is added in a second addition amount, and a ratio of the first addition amount to the total of the first addition amount and the second addition amount is 40-80%.

Description

Method for producing a negative electrode slurry for an all-solid-state battery, a negative electrode for an all-solid-state battery produced using the same, and an all-solid-state battery comprising the same

[0001] The present invention relates to a method for producing a negative electrode slurry for an all-solid-state battery, an all-solid-state battery negative electrode produced using the same, and an all-solid-state battery including the same.

[0002]

[0003] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in information and communication devices, but also in the automotive sector. Safety is particularly important in the automotive sector, as it is directly related to life.

[0004] Recently, all-solid-state batteries, which replace the electrolyte with a solid electrolyte, have been proposed. By eliminating the use of flammable organic dispersion media, all-solid-state batteries significantly reduce the risk of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can significantly improve safety compared to lithium-ion batteries that use electrolytes.

[0005]

[0006] The problem to be solved by the present invention is to provide a cathode slurry having excellent phase stability and a method for producing the same.

[0007] Another problem to be solved by the present invention is to provide an all-solid-state battery negative electrode having excellent performance and an all-solid-state battery including the same.

[0008]

[0009] A method for manufacturing a negative electrode slurry for an all-solid-state battery according to one embodiment of the present invention comprises: forming a first mixture by mixing a first thickener including a first binder and a first solvent and a negative electrode material; dispersing the first mixture to form a dispersion; mixing a second thickener including a second binder and a second solvent into the dispersion to form a second mixture; and mixing a polymer into the second mixture; wherein the first thickener is added in a first amount, the second thickener is added in a second amount, and a ratio of the first amount to the sum of the first and second amounts may be 40% to 80%.

[0010] An anode for an all-solid-state battery according to one embodiment of the present invention includes a cathode current collector and a cathode coating layer, wherein the cathode coating layer includes a carbon material, a metal, a first binder, a second binder, and a third binder, and the cathode coating layer can be manufactured by coating a cathode slurry manufactured by the above-described manufacturing method on the cathode current collector.

[0011] An all-solid-state battery according to one embodiment of the present invention may include the above-described negative electrode.

[0012]

[0013] A method for manufacturing a cathode slurry according to one embodiment of the present invention can provide a cathode slurry with excellent phase stability. Furthermore, by using the cathode slurry, an all-solid-state battery cathode with excellent performance and an all-solid-state battery comprising the same can be provided.

[0014]

[0015] Figure 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0016] Figure 2 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0017] FIG. 3 and FIG. 4 are a plan view and a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention, respectively.

[0018] Figure 5 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0019] FIG. 6 is a cross-sectional view of an all-solid-state battery including a gasket structure according to one embodiment of the present invention.

[0020] Figure 7 is an enlarged view illustrating a cathode coating layer according to embodiments of the present invention.

[0021] Figure 8 is a flow chart for explaining a method for manufacturing a cathode slurry according to embodiments of the present invention.

[0022] FIG. 9, FIG. 10, FIG. 11 and FIG. 12 are schematic diagrams each illustrating a method for manufacturing the above-described cathode slurry.

[0023] Figure 13 is a graph showing the results of evaluating the phase stability of cathode slurries according to examples and comparative examples of the present invention.

[0024]

[0025] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0026] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0027] Embodiments described herein will be described with reference to cross-sectional and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific shapes of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, and third are used to describe various components in various embodiments of the present specification, these components should not be limited by such terms. These terms are used only to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

[0028] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the words "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0029]

[0030] Figure 1 is a cross-sectional view of an all-solid-state battery (10) according to one embodiment of the present invention.

[0031] Referring to FIG. 1, an all-solid-state battery (10) according to one embodiment includes a positive electrode layer (100), a negative electrode layer (200) facing the positive electrode layer (100), and a solid electrolyte layer (300) disposed between the positive electrode layer (100) and the negative electrode layer (200). However, the present invention is not limited thereto, and the all-solid-state battery (10) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer (100) and the solid electrolyte layer (300) or between the negative electrode layer (200) and the solid electrolyte layer (300).

[0032] The positive electrode layer (100) of one embodiment includes a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0033] The cathode current collector (110) can provide a reference surface on which the cathode active material layer (120) is arranged. The cathode current collector (110) can include a plate or foil including, 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.

[0034] Meanwhile, unlike that illustrated in FIG. 1, in one embodiment of the present invention, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0035] A cathode active material is a material that can reversibly absorb and desorb lithium ions. The cathode active material may include, but is not necessarily limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more.

[0036] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mn b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mn b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mn d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiG bO2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f A compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0037] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to a sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which face-centered cubic lattices (fcc) formed by cations and anions respectively are arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질(121)이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지(10)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0038] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method of forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method of forming the coating layer includes, for example, spray coating, dipping, etc.

[0039] When the cathode active material contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the all-solid-state battery (10) can be increased, thereby reducing metal dissolution of the cathode active material (121) in a charged state. As a result, the cycle characteristics of the all-solid-state battery (10) in a charged state are improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the all-solid-state battery (10) is deteriorated by charge / discharge of the all-solid-state battery (10). An all-solid-state battery (10) with high cycle characteristics may have a small degree of deterioration of the all-solid-state battery (10) due to charge / discharge, and an all-solid-state battery (10) with low cycle characteristics may have a large degree of deterioration of the all-solid-state battery (10) due to charge / discharge.

[0040] The shape of the cathode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the cathode active material are not particularly limited.

[0041] The solid electrolyte may have a particle shape. The solid electrolyte may be dispersed between the positive electrode active materials. The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. Examples of the sulfide-based solid electrolyte include Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “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 It may include at least one selected from (0≤x≤2).

[0042] Sulfide-based solid electrolytes include, for example, 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 may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0043] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0044] Alternatively, the solid electrolyte may be the same as the solid electrolyte included in the solid electrolyte layer (300) described later.

[0045] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte (122-1) may be, for example, 15 GPa to 35 GPa.

[0046] The solid electrolyte included in the positive electrode active material layer (120) may have a smaller median particle size (D50) than the solid electrolyte included in the solid electrolyte layer (300). For example, the median particle size (D50) of the solid electrolyte included in the positive electrode active material layer (120) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the median particle size (D50) of the solid electrolyte included in the solid electrolyte layer (300). Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0047] The cathode active material layer (120) includes a conductive material. The conductive material may have conductivity without causing chemical changes in the all-solid-state battery (10), thereby increasing the conductivity of the cathode active material and the solid electrolyte.

[0048] The conductive material may include a carbon-based material. The conductive material may include, for example, one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0049] The positive electrode active material layer (120) may further include a binder. The binder may include a material for binding the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer (120) and improving bonding strength with the positive electrode current collector (110). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0050] Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 85 parts by weight or more and 92 parts by weight or less of the positive electrode active material. Based on 100 parts by weight of the total of the positive electrode active material, the solid electrolyte, the conductive material, and the binder, the positive electrode active material layer (120) may include 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0051] Based on 100 parts by weight of the solid electrolyte, the positive electrode active material layer (120) may include 1 part by weight or more and 50 parts by weight or less of a conductive material. If the conductive material is included in the positive electrode active material layer (120) in an amount of less than 1 part by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may decrease, thereby lowering the electrical conductivity of the positive electrode active material layer (120). If the conductive material is included in the positive electrode active material layer (120) in an amount of more than 50 parts by weight based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may be excessively high, so that a covering layer covering the surface of the solid electrolyte may not be properly formed.

[0052] The cathode active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the cathode active material, solid electrolyte, conductive agent, and binder described above.

[0053] Referring to FIG. 1, the negative electrode layer (200) includes a negative electrode current collector (210) and a negative electrode coating layer (220) disposed on the negative electrode current collector (210). The negative electrode coating layer (220) may include a negative electrode material and a binder.

[0054] The negative electrode current collector (210) can provide a reference surface on which the negative electrode coating layer (220) is arranged. The negative electrode current collector (210) can include, for example, a material that does not react with lithium, i.e., does not form an alloy or compound with lithium. The material constituting the negative electrode current collector (210) is not necessarily limited to, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), and any material that can be used as an electrode current collector can be used. The thickness of the negative electrode current collector can be 1 to 20 μm, for example, 5 to 15 μm, for example, 7 to 10 μm.

[0055] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) is, for example, in the form of a plate or foil. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0056] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0057] The cathode coating layer (220) will be described in detail later with reference to FIG. 7.

[0058] Referring to FIG. 1, a solid electrolyte layer (300) is disposed between the positive electrode layer (100) and the negative electrode layer (200) and includes a sulfide-based solid electrolyte (SE) having excellent lithium ion conductivity characteristics. The solid electrolyte (SE) included in the solid electrolyte layer (300) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the positive electrode active material layer (120) described above.

[0059] The solid electrolyte layer (300) of one embodiment may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, a heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material including Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0060] Sulfide-based solid electrolytes include, for example, 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 It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0061] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X cIt may be an argyrodite-type compound containing (0≤a≤2, 0≤c≤2), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0062] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. When the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0063] The solid electrolyte layer (300) may further include a binder. The binder included in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder (124) included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0064] The sulfide-based solid electrolyte included in the solid electrolyte layer (300) will be described in detail later with reference to FIG. 6.

[0065]

[0066] Figure 2 is a cross-sectional view of an all-solid-state battery (10) according to another embodiment of the present invention.

[0067] Referring to FIG. 2, the solid electrolyte layer (300) may include a first solid electrolyte layer (310) and a second solid electrolyte layer (320). The first solid electrolyte layer (310) may be adjacent to the positive electrode layer (100), and the second solid electrolyte layer (320) may be adjacent to the negative electrode layer (200).

[0068] The first solid electrolyte layer (310) and the second solid electrolyte layer (320) may have different thicknesses. The first solid electrolyte layer (310) may have a first thickness (TK1), and the second solid electrolyte layer (320) may have a second thickness (TK2). The first thickness (TK1) may be greater than the second thickness (TK2). For example, the first thickness (TK1) may be 2 to 100 times greater than the second thickness (TK2).

[0069]

[0070] Fig. 3 is a plan view of an all-solid-state battery (10) according to another embodiment of the present invention. Fig. 4 is a cross-sectional view taken along line A-A' of Fig. 3. In this embodiment, detailed descriptions of technical features overlapping with those previously described with reference to Figs. 1 and 2 will be omitted, and differences will be described in detail.

[0071] Referring to FIGS. 3 and 4, the area of ​​the anode layer (100) and the area of ​​the cathode layer (200) may be different from each other. Specifically, the area of ​​the cathode layer (200) may be larger than the area of ​​the anode layer (100). The anode layer (100) may be completely overlapped within the cathode layer (200).

[0072] In one embodiment of the present invention, the first solid electrolyte layer (310) may have substantially the same area as the positive electrode layer (100). The second solid electrolyte layer (320) may have substantially the same area as the negative electrode layer (200).

[0073] Specifically, the first solid electrolyte layer (310) may have a first width (WI1) in a first direction (D1). The second solid electrolyte layer (320) may have a second width (WI2) in the first direction (D1). The first width (WI1) may be smaller than the second width (WI2). The first solid electrolyte layer (310) may have a third width (WI3) in the second direction (D2). The second solid electrolyte layer (320) may have a fourth width (WI4) in the second direction (D2). The third width (WI3) may be smaller than the fourth width (WI4).

[0074] The all-solid-state battery (10) according to the present embodiment can be manufactured by forming a first laminate of a positive electrode layer (100) and a first solid electrolyte layer (310), forming a second laminate of a negative electrode layer (200) and a second solid electrolyte layer (320), and then laminating the first laminate and the second laminate.

[0075]

[0076] FIG. 5 is a cross-sectional view taken along line A-A' of FIG. 3 to explain an all-solid-state battery according to another embodiment of the present invention.

[0077] Referring to FIG. 5, the negative electrode layer (200) of the all-solid-state battery (10) may further include a lithium metal layer (400) between the negative electrode current collector (210) and the negative electrode coating layer (220). The thickness of the lithium metal layer (400) may further increase when the all-solid-state battery (10) is charged. The negative electrode coating layer (220) serves as a protective layer for the lithium metal layer (400), and at the same time, may suppress the growth of lithium dendrites from the lithium metal layer (400).

[0078] The lithium metal layer (400) may be a metal thin film containing lithium or a lithium alloy. The lithium alloy may include, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., and any lithium alloy may be used. The lithium metal layer (400) may contain one of these alloys or lithium. Alternatively, the lithium metal layer (400) may contain various types of alloys.

[0079] The lithium metal layer (400) may have a fifth width (WI5) in the first direction (D1). The fifth width (WI5) may be equal to or greater than the first width (WI1). The fifth width (WI5) may be equal to or less than the second width (WI2). For example, the fifth width (WI5) may be greater than the first width (WI1) and less than the second width (WI2).

[0080]

[0081] FIG. 6 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention.

[0082] Referring to FIG. 6, the all-solid-state battery (10) may include a gasket structure (400). The gasket structure (400) may fill in the step difference in the side surface of the all-solid-state battery (10) caused by the difference in the area of ​​the first laminate and the second laminate. The gasket structure (400) may surround the side surfaces of the first laminate of the all-solid-state battery (10) along the first and second directions (D1, D2). For example, the thickness of the gasket structure (400) may be substantially the same as the thickness of the first laminate. Accordingly, even when the first and second laminates having different areas are laminated and pressed, damage to the step difference in the side surface of the all-solid-state battery can be prevented. The term “substantially the same thickness” may be defined as a thickness that can prevent damage to the step difference in the side surface of the all-solid-state battery even when the first and second laminates having different areas are laminated and pressed.

[0083]

[0084] cathode coating layer

[0085] Fig. 7 is an enlarged cross-sectional view of a portion of a cathode coating layer (220, see Fig. 1) according to embodiments of the present invention. Fig. 7 shows an enlarged view of area M of Fig. 1.

[0086] Referring to Fig. 7, the negative electrode coating layer (220) may include carbon material (CRB), metal (MET), a first binder (BND1), a second binder (BND2), and a third binder (BND3). The negative electrode coating layer (220) may be manufactured by coating a negative electrode slurry, which will be described later, on a negative electrode current collector (210).

[0087] The negative electrode coating layer (220) can allow lithium metal to grow between it and the negative electrode current collector (210) when the all-solid-state battery (10) is charged. The negative electrode coating layer (220) can act as a protective layer for the lithium metal and suppress the precipitation and growth of lithium dendrites.

[0088] The cathode coating layer (220) may include, for example, one or more selected from carbon materials and metals (or metalloids).

[0089] The carbon material may be amorphous carbon, in particular. Amorphous carbon includes, but is not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), carbon nanotubes, ketjen black (KB), and graphene. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon. That is, the carbon material may include at least one selected from the group consisting of carbon black (CB), acetylene black (AB), furnace black (FB), carbon nanotubes, ketjen black (KB), and graphene.

[0090] The metal (or metalloid) includes, but is not limited to, one or more selected from the group consisting of gold (Au), indium (In), germanium (Ge), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and may be a metal (or metalloid) that forms an alloy or compound with lithium. On the other hand, nickel (Ni) does not form an alloy with lithium and therefore is not a metal (or metalloid).

[0091] A metal (or metalloid) may have a particle form. The median particle size (D50) of a metal (or metalloid) having a particle form may be, for example, 4 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The median particle size (D50) of the metal (or metalloid) may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the metal (or metalloid) has a median particle size (D50) in this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0092] The cathode coating layer (220) may include one type of material among these materials, or may include a mixture of multiple different materials. For example, the cathode coating layer (220) may include only amorphous carbon, or may include one or more selected from the group consisting of gold (Au), indium (In), germanium (Ge), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0093] In one embodiment, the cathode coating layer (220) may include a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), indium (In), germanium (Ge), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold (Au), etc., may be, for example, 1:2 to 4:1 by weight. For example, the weight ratio of the carbon material and the metal may be 1:2 to 4:1, 1.2:1 2:1, 3:1, or 4:1. By having the above weight ratio, the carbon material and the metal can secure sufficient ionic conductivity, and the catalytic activity of the metal can be smoothly performed, thereby securing excellent output characteristics and capacity of the battery. In one embodiment, the weight ratio of the carbon material and the metal may be 3:1.

[0094] Since the negative electrode coating layer (220) includes binders (BND1, BND2, BND3), the negative electrode coating layer (220) can be stably formed on the negative electrode current collector (210). That is, the bonding strength between the negative electrode coating layer (220) and the negative electrode current collector (210) can be increased. In addition, cracking of the negative electrode coating layer (220) is suppressed despite changes in the volume and / or relative positions of the negative electrode coating layer (220) during the charge and discharge process. When the negative electrode coating layer (220) does not include binders (BND1, BND2, BND3), the negative electrode coating layer (220) can be easily separated from the negative electrode current collector (210). As the negative electrode coating layer (220) is detached from the negative electrode collector (210), the negative electrode collector (210) may come into contact with the solid electrolyte layer at the exposed portion, thereby increasing the possibility of a short circuit occurring.

[0095] The negative electrode coating layer (220) is manufactured, for example, by providing a mixture in which materials constituting the negative electrode coating layer (220) are dispersed onto the negative electrode current collector (210). Since the binders (BND1, BND2, BND3) are included in the materials constituting the negative electrode coating layer (220), stable dispersion of the negative electrode active material in the mixture is possible. In addition, the binders (BND1, BND2, BND3) can improve the adhesive strength of the negative electrode coating layer (220). For example, when applying the mixture onto the negative electrode current collector (210) by screen printing, it is possible to suppress clogging of the screen (e.g., clogging by aggregates of materials constituting the negative electrode coating layer) by the binders (BND1, BND2, BND3).

[0096] The first binder (BND1) may include at least one selected from the group consisting of an acrylate-based binder, a polyvinylidene fluoride-based binder, a polyvinylpyrrolidone-based binder, a polyvinyl alcohol-based binder, and a cellulose-based binder. In one embodiment, the first binder (BND1) may be a cellulose-based binder. In one embodiment, the first binder (BND1) may be a water-based binder.

[0097] The above acrylate binder may be, for example, polyacrylic acid (PAA), polymethylmethacrylate, polyisobutylmethacrylate, polyethylacrylate, polybutyl acrylate, or poly(2-ethylhexyl acrylate).

[0098] The above polyvinylidene fluoride-based binder is, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene, polyvinylidene fluoride-co-hexafluoropropylene. It may be poly(vinylidene fluoride-co-ethylenefluoride-hexafluoropropylene) or polyvinylidene fluoride-co-trichloroethylene.

[0099] The above polyvinylpyrrolidone-based binder may be, for example, polyvinylpyrrolidone.

[0100] The above polyvinyl alcohol-based binder may be, for example, polyvinyl alcohol.

[0101] The cellulosic binder may be, for example, carboxymethylcellulose (CMC), methylcellulose (MC), hydroxypropylcellulose (HPC), methyl hydroxypropyl cellulose (MHPC), ethyl hydroxyethyl cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), or cellulose gum. In one embodiment, the first binder may be carboxymethylcellulose (CMC).

[0102] The first binder (BND1) can come into contact with materials (metal, carbon material, etc.) constituting the cathode coating layer (220) and can uniformly disperse the materials within the cathode coating layer (220).

[0103] The second binder (BND2) may include at least one selected from the group consisting of an acrylate-based binder, a polyvinylidene fluoride-based binder, a polyvinylpyrrolidone-based binder, a polyvinyl alcohol-based binder, and a cellulose-based binder. In one embodiment, the second binder (BND2) may be a cellulose-based binder. In one embodiment, the second binder (BND2) may be a water-based binder. Specific types of the acrylate-based binder, the polyvinylidene fluoride-based binder, the polyvinylpyrrolidone-based binder, the polyvinyl alcohol-based binder, and the cellulose-based binder are as described above.

[0104] In one embodiment, the first binder (BND1) and the second binder (BND2) may be identical to each other. In another embodiment, the first binder (BND1) and the second binder (BND2) may be different from each other.

[0105] The second binder (BND2) can come into contact with materials (metal, carbon material, etc.) constituting the cathode coating layer (220) and can uniformly disperse the materials within the cathode coating layer (220).

[0106] The third binder (BND3) may include at least one binder selected from the group consisting of a rubber-based binder, an imide-based binder, a nitrile-based binder, an acetate-based binder, and a cyano-based binder. In one embodiment, the third binder (BND3) may be a water-based binder. The third binder (BND3) may be different from the first binder (BND1) and the second binder (BND3).

[0107] The above imide binder may be, for example, polyimide or polyamide imide.

[0108] The above nitrile-based binder may be, for example, polyacrylonitrile or an acrylonitrile-styrene-butadiene copolymer.

[0109] The acetate-based binder may be, for example, polyvinylacetate, polyethylene-co-vinyl acetate, cellulose acetate, cellulose acetate butyrate, or cellulose acetate propionate.

[0110] The above cyano-based binder may be, for example, cyanoethyl sucrose.

[0111] In one embodiment of the present invention, the third binder may be styrene butadiene rubber (SBR). In another embodiment of the present invention, the third binder may be nitrile butadiene rubber (NBR).

[0112] For example, the molecular weight of the third binder (BND2) may be different from the molecular weight of the first binder (BND1) and the molecular weight of the second binder (BND2). The weight average molecular weight (Mw) of the third binder (BND3) may be 60,000 g / mol to 1,000,000 g / mol, or 60,000 g / mol to 80,000 g / mol.

[0113] The third binder (BND3) can come into contact with materials (metal, carbon material, first binder, second binder, etc.) constituting the cathode coating layer (220), can improve the adhesive strength of the cathode coating layer (220), and can uniformly disperse the materials within the cathode coating layer (220).

[0114] Based on 100 parts by weight of the cathode coating layer (220), the cathode coating layer (220) may include 3 to 15 parts by weight, or 4 to 13 parts by weight, of the first, second, and third binders (BND1, BND2, BND3). For example, based on 100 parts by weight of the cathode coating layer (220), the cathode coating layer (220) may include 1 to 5 parts by weight of the first and second binders (BND1, BND2). For example, based on 100 parts by weight of the cathode coating layer (220), the cathode coating layer (220) may include 2 to 10 parts by weight of the third binder (BND3). When the content of the binders (BND1, BND2, BND3) satisfies the above-described range, the stability and coating adhesion of the cathode slurry can be improved. Accordingly, the materials constituting the cathode coating layer (220) can be uniformly dispersed within the cathode coating layer (220), the adhesive strength of the cathode coating layer (220) can be improved, and the resistance of the cathode including the same can be lowered.

[0115] The cathode coating layer (220) may further include other additives in addition to carbon material, metal (or metalloid), and binder (BND1, BND2, BND3). The cathode coating layer (220) may further include, for example, fillers, coating agents, dispersants, ion conductive aids, etc.

[0116] The negative electrode layer (200) of the all-solid-state battery (10) according to the present embodiment can be manufactured using the negative electrode slurry described below. The negative electrode layer (200) can be manufactured using a conventional technique for manufacturing electrodes, and is not particularly limited thereto. Specifically, the above-described negative electrode slurry can be applied and dried on a negative electrode current collector (210) using a doctor blade, spray, bar coating, slot die coating, or the like, and then pressed to manufacture the electrode. An negative electrode coating layer (220) can be formed from the negative electrode slurry.

[0117] Below, the cathode slurry and its manufacturing method are described.

[0118]

[0119] Cathode slurry and method for producing the same

[0120] Figure 8 is a flowchart illustrating a method for manufacturing a cathode slurry for an all-solid-state battery according to embodiments of the present invention. Figures 9 to 12 are schematic diagrams illustrating each step of the above-described method for manufacturing a cathode slurry.

[0121] Referring to FIG. 8, a method for manufacturing a negative electrode slurry for an all-solid-state battery according to embodiments of the present invention may include: forming a first mixture by mixing a first amount of a first thickener and a negative electrode material (S100); dispersing the first mixture to form a dispersion (S300); forming a second mixture by mixing a second thickener into the dispersion (S500); and mixing a polymer into the second mixture (S700).

[0122]

[0123] Referring to FIG. 9, a first mixture (MXT1) can be prepared by mixing a cathode material (MAT) and a first thickener (TKN1).

[0124] The cathode material may include the carbon material (CRB) and metal (MET) described above.

[0125] For example, the carbon material (CRB) may include at least one selected from the group consisting of carbon black, acetylene black, furnace black, carbon nanotubes, ketjen black, and graphene.

[0126] The metal (MET) may include a metalloid. For example, it may include at least one selected from the group consisting of gold (Au), indium (In), germanium (Ge), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0127] For example, the weight ratio of carbon material (CRB) and metal (MET) can be 1:2 to 4:1, 1.2:1 2:1, 3:1 or 4:1.

[0128] The above cathode material (MAT) may further include additives. For example, it may further include at least one selected from the group consisting of fillers, coating agents, dispersants, and ion-conducting aids.

[0129] The first thickener (TKN1) may include a first binder (BND1) and a first solvent. The first thickener (TKN1) may increase the viscosity of the first mixture (MXT1).

[0130] For example, the first binder (BND1) may be the first binder described above. That is, the first binder (BND1) may include at least one selected from the group consisting of an acrylate-based binder, a polyvinylidene fluoride-based binder, a polyvinylpyrrolidone-based binder, a polyvinyl alcohol-based binder, and a cellulose-based binder. For example, the first binder (BND1) may be a cellulose-based binder.

[0131] The above acrylate binder may be, for example, polyacrylic acid (PAA), polymethylmethacrylate, polyisobutylmethacrylate, polyethylacrylate, polybutyl acrylate, or poly(2-ethylhexyl acrylate).

[0132] The above polyvinylidene fluoride-based binder is, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene, polyvinylidene fluoride-co-hexafluoropropylene. It may be poly(vinylidene fluoride-co-ethylenefluoride-hexafluoropropylene) or polyvinylidene fluoride-co-trichloroethylene.

[0133] The above polyvinylpyrrolidone-based binder may be, for example, polyvinylpyrrolidone.

[0134] The above polyvinyl alcohol-based binder may be, for example, polyvinyl alcohol.

[0135] The cellulose-based binder may be, for example, carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxypropyl cellulose (HPC), methyl hydroxypropyl cellulose (MHPC), ethyl hydroxyethyl cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), or cellulose gum. In one embodiment, the first binder (BND1) may be carboxymethyl cellulose (CMC).

[0136] The first binder (BND1) can come into contact with the materials (metal (MET), carbon material (CRB), etc.) and can uniformly disperse the materials in the negative electrode slurry.

[0137] For example, the first solvent may be an aqueous solvent or a non-aqueous solvent. In one embodiment, the first solvent may be water.

[0138] As used herein, "aqueous solvent" refers to solvents containing water as a main component. For example, the aqueous solvent may include water. In addition, the aqueous solvent may further include at least one selected from the group consisting of methanol, ethanol, ethylene glycol, diethylene glycol, and glycerol.

[0139] The content of the first binder (BND1) in the first thickener (TKN1) may be 0.5 wt% to 5 wt%. For example, the content of the first binder in the binder solution may be 0.5 wt% to 4 wt%, 0.8 wt% to 3.5 wt%, or 0.8 wt% to 3 wt%, or 1 wt%.

[0140] The viscosity of the first thickener (TKN1) may be 500 cps to 3500 cps. For example, the viscosity of the first thickener (TKN1) may be 500 cps to 2000 cps, or 2000 cps to 3500 cps. For example, the viscosity of the first thickener (TKN1) having a content of 1 wt% of the first binder (BND1) may satisfy the above-described range.

[0141] When the content and viscosity of the first binder (BND1) of the first thickener (TKN1) each satisfy the above-described range, the amount of contact between the first binder (BND1) and the materials (metal (MET), carbon material (CRB), etc.) can be increased, and the materials can be uniformly dispersed in the negative electrode slurry.

[0142] The first thickener (TKN1) may be added in a first amount. The first amount may be a portion of the total amount of the desired first thickener (TKN1) and the second thickener (TKN2). That is, in this step, only a portion of the total amount of the desired first thickener (TKN1) and the second thickener (TKN2) may be added.

[0143] By adding the first additive amount of the first thickener (TKN1), the solid content in the first mixture (MTX1) can be 15 wt% to 60 wt%. The solid content in the first mixture (MTX1) can include the negative electrode material (MAT) and the first binder (BND1). For example, the solid content in the first mixture (MTX1) can be 20 wt% to 60 wt%, 30 wt% to 60 wt%, or 40 wt% to 50 wt%. In other words, the first additive amount of the first thickener (TKN1) can be added so that the solid content in the first mixture (MTX1) satisfies the above-described range.

[0144] The cathode material (MAT) and the first thickener (TKN1) can be mixed. The mixing method is not limited. In one embodiment, the mixing can be performed by adding the first thickener (TKN1) to the cathode material (MAT) and then stirring the mixture using a planetary mixer at 20°C to 60°C for 20 to 200 minutes.

[0145]

[0146] Referring to FIG. 10, the first mixture (MXT1) may be dispersed, and a dispersion may be formed (S300). Dispersion may be performed by a disperser. The type of the disperser is not limited as long as it can apply a shear force or an impact force to the first mixture (MXT1). For example, the disperser (MXT1) may be a bead mill, a ball mill, a spike mill, a basket mill, an attrition mill, an ultrasonic disperser, or a high-pressure homogenizer. More specifically, the disperser may be a “disperser including a grinding medium (GMD).” In this specification, the term “disperser including grinding media (GMD)” refers to a device that includes grinding media such as balls or beads inside, and is a general term for a device that can grind and disperse particles by causing physical impact on the material by the grinding media. For example, the disperser including grinding media (GMD) may be selected from the group consisting of a bead mill, a ball mill, a spike mill, a basket mill, and an attrition mill.

[0147] By using a “disperser including a grinding media (GMD)”, it is possible to prevent the first binder (BND1) from being degenerated or destroyed due to excessive grinding action, thereby increasing the dispersion effect.

[0148] In one embodiment, the average particle diameter (D50) of the grinding medium may be 0.5 mm or greater. Specifically, the average particle diameter (D50) of the grinding medium may be 0.6 mm or greater or 0.8 mm or greater. For example, the average particle diameter (D50) of the grinding medium may be 0.5 mm to 5 mm, 0.6 mm to 4 mm, 0.6 mm to 3 mm, or 0.8 mm to 2 mm. When the average particle diameter (D50) of the grinding medium is less than 0.5 mm, the battery performance may be degraded due to plateletization of the metal in the negative electrode material. In addition, when the average particle diameter (D50) of the grinding medium exceeds 5 mm, proper grinding may not be achieved, and thus the dispersion effect of the first mixture (MXT1) may be reduced.

[0149] In one embodiment of the present invention, the dispersion of the first mixture (MXT1) may be performed using a bead mill. The dispersion may include dispersion using high energy.

[0150] The dispersion time of the first mixture (MXT1) can be appropriately selected depending on the type and operating conditions of the disperser used. For example, dispersion of the first mixture can be performed for 10 to 120 minutes.

[0151] Through this step, a dispersion in which the cathode material (MAT) and the first thickener (TKN1) are evenly dispersed can be formed.

[0152]

[0153] Referring to FIG. 11, a second thickener (TKN2) of a second amount may be mixed into the dispersion (DSP) to form a second mixture (MXT2).

[0154] The second thickener (TKN2) may include a second binder (BND2) and a second solvent. The second thickener (TKN2) may increase the viscosity of the second mixture (MXT2).

[0155] For example, the second binder (BND2) may include at least one selected from the group consisting of an acrylate-based binder, a polyvinylidene fluoride-based binder, a polyvinylpyrrolidone-based binder, a polyvinyl alcohol-based binder, and a cellulose-based binder. For example, the second binder (BND2) may be a cellulose-based binder.

[0156] The above acrylate binder may be, for example, polyacrylic acid (PAA), polymethylmethacrylate, polyisobutylmethacrylate, polyethylacrylate, polybutyl acrylate, or poly(2-ethylhexyl acrylate).

[0157] The above polyvinylidene fluoride-based binder is, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene, polyvinylidene fluoride-co-hexafluoropropylene. It may be poly(vinylidene fluoride-co-ethylenefluoride-hexafluoropropylene) or polyvinylidene fluoride-co-trichloroethylene.

[0158] The above polyvinylpyrrolidone-based binder may be, for example, polyvinylpyrrolidone.

[0159] The above polyvinyl alcohol-based binder may be, for example, polyvinyl alcohol.

[0160] The cellulose-based binder may be, for example, carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxypropyl cellulose (HPC), methyl hydroxypropyl cellulose (MHPC), ethyl hydroxyethyl cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), or cellulose gum. In one embodiment, the second binder (BND2) may be carboxymethyl cellulose (CMC).

[0161] In one embodiment, the viscosity of the second thickener (TKN2) may be substantially the same as the viscosity of the first thickener (TKN1). Substantially the same viscosity may mean that the difference between the viscosity of the first thickener (TKN1) and the viscosity of the second thickener (TKN2) is within 10% when compared to the greater of the viscosity of the first thickener (TKN1) or the viscosity of the second thickener (TKN2). For example, the second binder (BND2) included in the second thickener (TKN2) may be the same as the first binder (BND1) included in the first thickener (TKN1).

[0162] In another embodiment, the viscosity of the second thickener (TKN2) may be different from the viscosity of the first thickener (TKN1). For example, the viscosity of the second thickener (TKN2) may be less than the viscosity of the first thickener (TKN1). For example, the viscosity of the second thickener (TKN2) may be greater than the viscosity of the first thickener (TKN1). For example, the second binder (BND2) included in the second thickener (TKN2) may be the same as or different from the first binder (BND1) included in the first thickener (TKN1).

[0163] The second binder (BND2) can come into contact with the materials (metal (MET), carbon material (CRB), etc.) and can uniformly disperse the materials within the negative electrode slurry.

[0164] For example, the second solvent may be an aqueous solvent or a non-aqueous solvent. In one embodiment, the second solvent may be water. The aqueous solvent is as described above.

[0165] The content of the second binder (BND2) in the second thickener (TKN2) may be 0.5 wt% to 5 wt%. For example, the content of the second binder (BND2) in the second thickener (TKN2) may be 0.5 wt% to 4 wt%, 0.8 wt% to 3.5 wt%, or 0.8 wt% to 3 wt%, or 1 wt%.

[0166] The viscosity of the second thickener (TKN2) may be 500 cps to 3500 cps. For example, the viscosity of the second thickener (TKN2) may be 500 cps to 2000 cps, or 2000 cps to 3500 cps. For example, the viscosity of the second thickener (TKN2) having a content of 1 wt% of the second binder (BND2) may satisfy the above-described range.

[0167] When the content and viscosity of the second binder (BND2) of the second thickener (TKN2) each satisfy the above-described range, the amount of contact between the second binder (BND2) and the materials (metal (MET), carbon material (CRB), etc.) can be increased, and the materials can be uniformly dispersed in the negative electrode slurry.

[0168] The second thickener (TKN2) may be added in a second amount. The second amount may be a portion of the total amount of the desired first thickener (TKN1) and the second thickener (TKN2). That is, in this step, the remainder of the total amount of the desired first thickener (TKN1) and the second thickener (TKN2) excluding the amount added in step S100 may be added.

[0169] By adding a second amount of the second thickener (TKN2), the solid content in the second mixture (MTX2) can be 15 wt% to 60 wt%. The solid content in the second mixture (MTX2) can include the negative electrode material (MAT), the first binder (BND1), and the second binder (BND2). For example, the solid content in the second mixture (MTX2) can be 15 wt% to 50 wt%, 15 wt% to 45 wt%, 20 wt% to 45 wt%, or 20 wt% to 30 wt%. In other words, the second thickener (TKN2) can be added in a second amount such that the solid content in the second mixture (MTX2) satisfies the above-described range.

[0170] If the solids content in the second mixture (MXT2) falls outside the above range, the solids content in the second mixture (MXT2) can be adjusted by adding a solvent. The solvent is the same as described above. In one embodiment, the solvent may be an aqueous solvent. For example, the solvent may include water.

[0171] Referring back to FIGS. 9 and 11, the first thickener (TKN1) and the second thickener (TKN2) may be added separately before and after dispersion. The ratio of the first addition amount to the sum of the first addition amount and the second addition amount (A / (A+B)) may be 40% to 80%. The ratio of the second addition amount to the sum of the first addition amount and the second addition amount (B / (A+B)) may be 20% to 60%. During dispersion (S300), since high energy is applied to the first mixture (MXT1), the molecular weight of the first binder (BND1) constituting the first thickener (TKN1) may be reduced, thereby deteriorating the phase stability of the final manufactured negative electrode slurry. However, if the ratio of the first addition amount (A / (A+B)) and the ratio of the second addition amount (B / (A+B)) satisfy the ranges described above, the viscosity of the dispersion (DSP) can be increased, and a cathode slurry with improved phase stability can be provided.

[0172] The first binder (BND1) in the first thickener (TKN1) and the second binder (BND2) in the second thickener (TKN2) can uniformly disperse the constituent materials in the second mixture (MXT2). To this end, the first thickener (TKN1) and the second thickener (TKN2) can be added so that the total weight ratio of the first binder (BND1) and the second binder (BND2) with respect to the weight of the negative electrode material (MAT) is 1% to 6%. For example, the first thickener (TKN1) and the second thickener (TKN2) can be added so that the total weight ratio of the first binder (BND1) and the second binder (BND2) with respect to the weight of the negative electrode material (MAT) is 2% to 6%, or 2.5% to 6%.

[0173] Accordingly, the total content of the first binder (BND1) and the second binder (BND2) in the second mixture (MXT2) may be 1 wt% to 10 wt%. If the content of the first and second binders (BND1, BND2) in the second mixture (MTX2) is less than the above range, the negative electrode material may not be sufficiently dispersed. If the content of the first and second binders (BND1, BND2) exceeds the above range, the first and second binders (BND1, BND2) may be excessively adsorbed on the surface of the carbon material or metal particles, which may hinder the movement of lithium ions and increase the internal resistance of the battery.

[0174] The manufactured second mixture (MXT2) may be in the form of a slurry. The second mixture (MXT2) may have a viscosity of 1000 cps to 4000 cps. For example, the viscosity of the second mixture (MXT2) may be 1000 cps to 3500 cps, 1500 cps to 3000 cps, 1500 cps to 2500 cps, or 2000 cps to 2500 cps.

[0175]

[0176] Referring to Fig. 12, a cathode slurry (SLY) can be formed by mixing a polymer (PLM) into a second mixture (MXT2) (S700).

[0177] The polymer (PLM) may include at least one selected from the group consisting of a rubber-based binder, an imide-based binder, a nitrile-based binder, an acetate-based binder, and a cyano-based binder. For example, the polymer (PLM) may be a rubber-based binder.

[0178] The rubber-based binder may be, for example, styrene butadiene rubber (SBR) or nitrile butadiene rubber (NBR). In one embodiment, the rubber-based binder may be styrene butadiene rubber.

[0179] The above imide binder may be, for example, polyimide or polyamide imide.

[0180] The above nitrile-based binder may be, for example, polyacrylonitrile or an acrylonitrile-styrene-butadiene copolymer.

[0181] The acetate-based binder may be, for example, polyvinylacetate, polyethylene-co-vinyl acetate, cellulose acetate, cellulose acetate butyrate, or cellulose acetate propionate.

[0182] The above cyano-based binder may be, for example, cyanoethyl sucrose.

[0183] Polymers (PLM) can have excellent adhesive properties. By adding the polymer (PLM) after the dispersion step (S300), the polymer (PLM) can be prevented from being destroyed and denatured by the disperser, thereby reducing the adhesive properties.

[0184] For example, the polymer (PLM) may be provided in a solution state dissolved in a third solvent. For example, the third solvent may be an aqueous solvent or a non-aqueous solvent. In one embodiment, the third solvent may be water.

[0185] The polymer (PLM) content in the polymer solution may be from 5 wt% to 60 wt%. For example, the polymer (PLM) content in the polymer solution may be from 6 wt% to 55 wt%, from 8 wt% to 50 wt%, from 10 wt% to 45 wt%, or from 40 wt% to 50 wt%.

[0186] The viscosity of the polymer solution may be from 10 cps to 4000 cps. For example, the viscosity of the polymer solution may be from 30 cps to 3000 cps, from 50 cps to 2500 cps, from 50 cps to 1000 cps, or from 50 cps to 100 cps. For example, the viscosity of a polymer solution having a polymer (PLM) content of 1 wt% may satisfy the above-described range.

[0187] When the content and viscosity of the polymer (PLM) of the polymer solution each satisfy the ranges described above, the coating adhesion and the dispersion stability of the slurry can be improved.

[0188] The polymer (PLM) may be added so that the content of the polymer (PLM) in the negative electrode slurry (SLY) is 0.5 wt% to 10 wt%. For example, the content of the polymer (PLM) in the negative electrode slurry (SLY) may be 1 wt% to 8 wt% or 1.5 wt% to 6 wt%. Within the above range, the negative electrode slurry (SLY) has appropriate adhesiveness and viscosity, so that the negative electrode slurry can be uniformly applied onto the current collector during electrode manufacture.

[0189] The second mixture (MXT2) and the polymer (PLM) may be mixed. The mixing method of the second mixture (MXT2) and the polymer (PLM) is not limited, and may be, for example, stirring. In one embodiment, the mixing may be performed using a planetary mixer at a temperature of 20°C to 60°C for 10 to 120 minutes.

[0190]

[0191] A method for manufacturing a negative electrode slurry according to a comparative example of the present invention comprises: forming a third mixture by mixing the first thickener (TKN1) and the negative electrode material (MAT); dispersing the third mixture to form a dispersion; and mixing the polymer (PLM) into the dispersion; wherein the first thickener (TKN1) is added in a third amount, and the third amount may be the sum of the first amount and the second amount. That is, in the method for manufacturing a negative electrode slurry according to a comparative example of the present invention, unlike the above-described example, the first thickener (TKN1) is not added in parts, but the entire amount of the first thickener (TKN1) that is intended for addition can be added in the step of mixing with the negative electrode material. Accordingly, when dispersed, high energy is applied to the third mixture, so that the molecular weight of the first binder (BND1) constituting the first thickener (TKN1) may decrease, and thus the phase stability of the final manufactured negative electrode slurry may deteriorate.

[0192]

[0193] The cathode slurry manufactured according to the method for manufacturing the cathode slurry according to the embodiment of the present invention can have the following effects.

[0194] The cathode slurry of the present invention may have excellent dispersibility and adhesive strength. In addition, the viscosity of the cathode slurry of the present invention may be 500 to 4000 cps, 1000 to 3500 cps, or 1500 to 3000 cps. In addition, the cathode slurry of the present invention may have excellent phase stability.

[0195] Accordingly, an all-solid-state battery manufactured using the negative electrode slurry of the present invention can have excellent performance.

[0196]

[0197] Hereinafter, the present invention will be described in more detail through examples. However, these examples are intended to exemplify the present invention and the scope of the present invention is not limited to these examples.

[0198]

[0199] Example 1: Preparation of cathode slurry

[0200] A cathode slurry was prepared by adding thickener 1 (including binder 1) in portions.

[0201] A first mixture was formed by mixing a first thickener and a cathode material in a first addition amount (S100). As the cathode material, a mixture of silver (Ag) and carbon (C) in a weight ratio of 25:75 was prepared. As the first thickener, a 1 wt% aqueous solution of carboxymethylcellulose (CMC) having a viscosity of 1000 cps was prepared. The first addition amount was added so that the solid content (Ag, C, CMC) in the first mixture was 45%. Mixing was performed at a temperature of 25°C for 120 minutes, thereby preparing the first mixture.

[0202] The first mixture was placed in a bead mill and a dispersion process was performed for 60 minutes to obtain a dispersion (S300). The bead mill contained beads with an average particle diameter (D50) of 0.8 mm.

[0203] A second amount of the first thickener was mixed into the dispersion to form a second mixture (S500). The second amount was added so that the solids content (Ag, C, CMC) in the second mixture reached 25%. Mixing was performed at 25°C for 120 minutes, thereby producing a second mixture. The solids concentration of the second mixture was 25%, and the viscosity was 1582 cps.

[0204] A polymer (S700) was mixed into the second mixture. The polymer contained styrene-butadiene rubber (SBR) and was prepared in the form of an aqueous dispersion. Mixing was performed by stirring at 25°C for 60 minutes. Thus, a negative electrode slurry was obtained.

[0205]

[0206] Example 2: Preparation of cathode slurry

[0207] A cathode slurry was prepared by adding thickener 1 (including binder 1) and thickener 2 (including binder 2), respectively.

[0208] That is, the preparation was performed in the same manner as Example 1, except that the second amount of the second thickener was mixed instead of the second amount of the first thickener in step S500, and a 1 wt% aqueous solution of carboxymethyl cellulose (CMC) having a viscosity of 3500 cps was prepared as the second thickener.

[0209]

[0210] Comparative Example: Preparation of Cathode Slurry

[0211] The first thickener (including binder 1) was not added in parts, and the entire amount of the first thickener was added in the mixing step with the negative electrode material to prepare a negative electrode slurry.

[0212] That is, it was prepared in the same manner as Example 1, except that the first thickener was added in step S100 so that the content of solids (Ag, C, CMC) in the mixture became 25%, and the S500 step was omitted.

[0213]

[0214] Classification S100 S300 S500 S700 Example 1 Cathode material and the first amount of the first thickener mixed dispersant 2nd amount of the first thickener mixed polymer mixed Example 2 Cathode material and the first amount of the first thickener mixed dispersant 2nd amount of the second thickener mixed polymer mixed Comparative example Cathode material and the first thickener mixed dispersant polymer mixed-

[0215] Evaluation Example 1: Phase stability analysis of cathode slurry

[0216] The viscosity change rate of the cathode slurry according to the examples and comparative examples was analyzed. The viscosity change rate was measured using a rheometer (Anton paar).

[0217] Immediately after manufacturing the negative electrode slurry according to the examples and comparative examples (0 d) and 1 day later (1 d), the viscosity of the slurry according to the shear rate (1 / s) was measured, and the results are shown in Fig. 13. In addition, the viscosity and viscosity increase rate at Shear 10 immediately after manufacturing (0 d) and 1 day later (1 d) are shown in Table 2.

[0218]

[0219] Immediately after manufacturing (0d) 1 day later (1d) Viscosity increase rate (%) Shear 10 (cps) TI Shear 10 (cps) TI Example 1 15820.69 24160.725 2.8 Example 2 24130.74 34840.824 4.4 Comparative example 45270.38 147731.07 226.3 TI (Thixotropy Index): Viscosity at Shear 10 relative to viscosity at Shear 1

[0220] Referring to Table 2 and Fig. 13, the negative electrode slurries according to Examples 1 and 2 showed smaller viscosity changes over time compared to the negative electrode slurry according to Comparative Example. In other words, it was confirmed that the negative electrode slurries according to Examples 1 and 2 had excellent phase stability.

[0221]

[0222] Accordingly, by using the negative electrode slurry described in the claims of the present invention, the dispersibility and adhesive strength of the negative electrode slurry are excellent, and the negative electrode slurry is homogeneous, so that when coated on the negative electrode current collector, a negative electrode coating layer having a uniform composition and thickness can be obtained, and the adhesive strength of the negative electrode coating layer can be improved. Accordingly, it was confirmed that an all-solid-state battery with excellent performance can be manufactured.

[0223]

[0224] While embodiments of the present invention have been described with reference to the attached drawings, the present invention may be implemented in other specific forms without altering the technical spirit or essential features thereof. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

Claims

1. Forming a first mixture by mixing a first thickener and a negative electrode material including a first binder and a first solvent; Dispersing the first mixture to form a dispersion; Forming a second mixture by mixing a second thickener including a second binder and a second solvent into the above dispersion; and Mixing a polymer into the second mixture; including, The first thickener is added in a first amount, The second thickener is added in a second amount, The ratio of the first addition amount to the sum of the first and second addition amounts is 40% to 80%, Method for manufacturing a cathode slurry for an all-solid-state battery.

2. In paragraph 1, The above negative electrode material includes carbon material and metal, The weight ratio of the carbon material and the metal is 1.2 to 4:1, Method for manufacturing a cathode slurry for an all-solid-state battery.

3. In paragraph 2, The metal comprises at least one selected from the group consisting of gold (Au), indium (In), germanium (Ge), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). Method for manufacturing a cathode slurry for an all-solid-state battery.

4. In paragraph 2, The carbon material comprises at least one selected from the group consisting of carbon black, acetylene black, furnace black, carbon nanotube, ketjen black and graphene. Method for manufacturing a cathode slurry for an all-solid-state battery.

5. In paragraph 1, The first binder comprises at least one selected from the group consisting of an acrylate binder, a polyvinylidene fluoride binder, a polyvinylpyrrolidone binder, a polyvinyl alcohol binder, and a cellulose binder. Method for manufacturing a cathode slurry for an all-solid-state battery.

6. In paragraph 1, The viscosity of the first thickener is 500 cps to 3500 cps, Method for manufacturing a cathode slurry for an all-solid-state battery.

7. In paragraph 1, The above dispersion is performed by a disperser containing a grinding media, The above disperser comprises at least one selected from the group consisting of a bead mill, a ball mill, a spike mill, a basket mill, and an attrition mill. Method for manufacturing a cathode slurry for an all-solid-state battery.

8. In paragraph 1, The above dispersion is performed for 10 to 120 minutes, Method for manufacturing a cathode slurry for an all-solid-state battery.

9. In paragraph 1, The second binder comprises at least one selected from the group consisting of an acrylate binder, a polyvinylidene fluoride binder, a polyvinylpyrrolidone binder, a polyvinyl alcohol binder, and a cellulose binder. Method for manufacturing a cathode slurry for an all-solid-state battery.

10. In paragraph 1, The viscosity of the second thickener is 500 cps to 3500 cps, Method for manufacturing a cathode slurry for an all-solid-state battery.

11. In paragraph 1, The viscosity of the first thickener and the viscosity of the second thickener are different from each other. Method for manufacturing a cathode slurry for an all-solid-state battery.

12. In paragraph 1, The first and second binders are identical to each other, Method for manufacturing a cathode slurry for an all-solid-state battery.

13. In paragraph 1, The content of the first solid in the first mixture is 30 wt% to 60 wt%, and the first solid includes the negative electrode material and the first binder, The content of the second solid in the second mixture is 20 wt% to 30 wt%, and the second solid includes the negative electrode material, the first binder, and the second binder. Method for manufacturing a cathode slurry for an all-solid-state battery.

14. In paragraph 1, The polymer comprises at least one selected from the group consisting of a rubber-based binder, an imide-based binder, a nitrile-based binder, an acetate-based binder, and a cyano-based binder. Method for manufacturing a cathode slurry for an all-solid-state battery.

15. Including a negative electrode current collector and a negative electrode coating layer, The above cathode coating layer includes carbon material, metal, a first binder, a second binder, and a third binder, The above negative electrode coating layer is manufactured by coating the negative electrode slurry manufactured by the method of claim 1 on the negative electrode current collector. Cathode for all-solid-state batteries.

16. In paragraph 15, The first binder and the second binder are identical to each other, Cathode for all-solid-state batteries.

17. In paragraph 15, The first binder and the second binder are different from each other, Cathode for all-solid-state batteries.

18. In paragraph 15, The third binder is different from the first binder and the second binder, Cathode for all-solid-state batteries.

19. In paragraph 15, The first binder and the second binder each include at least one selected from the group consisting of an acrylate binder, a polyvinylidene fluoride binder, a polyvinylpyrrolidone binder, a polyvinyl alcohol binder, and a cellulose binder, The third binder comprises at least one selected from the group consisting of a rubber-based binder, an imide-based binder, a nitrile-based binder, an acetate-based binder, and a cyano-based binder. Cathode for all-solid-state batteries.

20. An all-solid-state battery comprising the negative electrode described in Article 15.

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