Positive electrode for all-solid-state battery, all-solid-state battery comprising same, and method for manufacturing positive electrode for all-solid-state battery

Abstract

The present invention relates to a positive electrode for an all-solid-state battery, an all-solid-state battery comprising same, and a method for manufacturing a positive electrode for an all-solid-state battery and, more particularly, to a positive electrode for an all-solid-state battery comprising: a positive electrode current collector; a positive electrode active material layer disposed on the positive electrode current collector; and a porous film disposed within the positive electrode active material layer. The positive electrode active material layer has a first thickness (a), and the porous film is positioned within the positive electrode active material layer at a first distance (b) from the positive electrode current collector, and the first thickness (a) and the first distance (b) satisfy the relationship of formula 1. [formula 1] 0.5 ≤ b / a ≤ 0.8.

Description

Anode for an all-solid-state battery, an all-solid-state battery including the same, and a method for manufacturing the anode for an all-solid-state battery

[0001] The present invention relates to a positive electrode for an all-solid-state battery, an all-solid-state battery including the same, and a method for manufacturing the positive electrode for an all-solid-state battery, and more specifically, to a positive electrode including a porous polymer sheet in its structure, an all-solid-state battery including the same, and a method for manufacturing 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 high current density positive electrode for an all-solid-state battery with a large capacity in a limited volume.

[0007] Another problem to be solved by the present invention is to provide an all-solid-state battery having a large capacity and uniform thickness and quality, thereby achieving a long life and high efficiency.

[0008] Another problem to be solved by the present invention is to provide a method for manufacturing a positive electrode for an all-solid-state battery that has a low manufacturing difficulty and is capable of mass production.

[0009]

[0010] According to the concept of the present invention, a positive electrode for an all-solid-state battery may include: a positive electrode current collector; a positive electrode active material layer on the positive electrode current collector; and a porous film disposed within the positive electrode active material layer. The positive electrode active material layer has a first thickness (a), and the porous film is positioned within the positive electrode active material layer at a first distance (b) from the positive electrode current collector, and the first thickness (a) and the first distance (b) may satisfy the relationship of the following Equation 1.

[0011] [Formula 1]

[0012] 0.5 < (b / a) < 0.8

[0013]

[0014] According to the concept of the present invention, an all-solid-state battery may include: the positive electrode; a negative electrode opposite the positive electrode; and a solid electrolyte layer disposed between the positive electrode and the negative electrode.

[0015]

[0016] According to the concept of the present invention, a method for manufacturing a positive electrode for an all-solid-state battery may include: forming a first preliminary active material layer on a positive electrode substrate; disposing a composite layer including a porous film on the first preliminary active material layer; and pressing the positive electrode substrate, the first preliminary active material layer, and the composite layer, which are sequentially laminated, together. Forming the composite layer may include providing a preliminary porous film; and providing a positive electrode active material on the preliminary porous film to form a porous film and a preliminary composite active material layer. In the composite layer, the porous film may be disposed within the preliminary composite active material layer.

[0017]

[0018] According to one embodiment of the present invention, an all-solid-state battery positive electrode is disposed within a positive electrode active material layer and includes a porous film impregnated with an active material therein, thereby enabling a high loading level. Accordingly, an all-solid-state battery including the all-solid-state battery positive electrode of the embodiment can achieve a high current density.

[0019] According to another embodiment of the present invention, a porous film having a self-standing film form is rolled onto a cathode substrate and a cathode active material layer to form a cathode for an all-solid-state battery, thereby manufacturing a cathode for an all-solid-state battery having a high loading level through a relatively simple process.

[0020]

[0021] Figure 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0022] Figure 2 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0023] 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.

[0024] Figure 5 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0025] 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.

[0026] FIG. 7 and FIG. 8 are cross-sectional views showing a positive electrode included in an all-solid-state battery according to one embodiment of the present invention.

[0027] Figure 9 is a cross-sectional view showing an electrode included in an all-solid-state battery according to another embodiment of the present invention.

[0028] FIGS. 10A and 10B are cross-sectional views of one step of forming a composite layer according to one embodiment of the present invention.

[0029] Figures 11 to 13 are cross-sectional views showing each step of a method for manufacturing an anode according to one embodiment of the present invention.

[0030] Figure 14 is a graph showing the life characteristics of all-solid-state batteries according to examples and comparative examples of the present invention.

[0031]

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0037] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0038] Figure 1 is a cross-sectional view of an all-solid-state battery (10) according to one embodiment of the present invention.

[0039] 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).

[0040] 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.

[0041] 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.

[0042] 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).

[0043] The cathode active material layer (120) may include a cathode active material, a solid electrolyte, a conductive material, and a binder.

[0044] The 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.

[0045] 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 Nor 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 Nor 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 Nor 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 b O2(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-fA 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.

[0046] 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 zO2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지(10)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0047] 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.

[0048] 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 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 due to 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.

[0049] 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.

[0050] 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).

[0051] 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-xI 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.

[0052] 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.

[0053] Alternatively, the sulfide-based solid electrolyte may be the same as the solid electrolyte included in the solid electrolyte layer (300) described later.

[0054] 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 can be 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 may be, for example, 15 GPa to 35 GPa.

[0055] 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.

[0056] The cathode active material layer (120) may include 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.

[0057] The conductive material may include a carbon-based material. For example, the conductive material may include one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0058] 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, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0059] 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.

[0060] 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.

[0061] 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.

[0062]

[0063] Referring to FIG. 1, the negative electrode layer (200) includes a negative electrode current collector (210) and a negative electrode active material layer (220) disposed on the negative electrode current collector (210). The negative electrode active material layer (220) may include a negative electrode active material and a binder.

[0064] The negative electrode current collector (210) can provide a reference surface on which the negative electrode active material 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.

[0065] 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.

[0066] The negative electrode active material included in the negative electrode active material layer (220) may have a particle form. The median particle size average particle diameter (D50) of the negative electrode active material 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 average particle diameter (D50) of the negative electrode active material may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the negative electrode active material has a median particle size average diameter (D50) in this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size average diameter (D50) may be a median diameter measured using a laser particle size distribution meter.

[0067] The negative electrode active material may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0068] The carbon-based negative electrode active material may be amorphous carbon, in particular. Examples of amorphous carbon include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), 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.

[0069] The metal or metalloid negative electrode active material includes, but is not necessarily limited to, one or more 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), and may be a metal negative electrode active material or a metalloid negative electrode active material 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 negative electrode active material.

[0070] The negative electrode active material layer (220) includes one type of negative electrode active material among these negative electrode active materials, or includes a mixture of multiple different negative electrode active materials. For example, the negative electrode active material layer (220) may include only amorphous carbon, or may include one or more 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).

[0071] In one embodiment, the negative electrode active material layer (220) may include a mixture of amorphous carbon and one or more 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). The mixing ratio of the mixture of amorphous carbon and gold (Au), etc., may be, for example, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1 by weight, but is not necessarily limited to this range and may be selected according to the required characteristics of the all-solid-state battery (10). When the negative electrode active material has this composition, the cycle characteristics of the all-solid-state battery (10) may be further improved.

[0072] The binder included in the negative electrode active material layer (220) is, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto. The binder may include a single binder or a plurality of different binders.

[0073] Since the negative electrode active material layer (220) includes a binder, the negative electrode active material layer (220) can be stably formed on the negative electrode current collector (210). That is, the bonding strength between the negative electrode active material layer (220) and the negative electrode current collector (210) can be increased. In addition, cracking of the negative electrode active material layer (220) is suppressed despite changes in the volume and / or relative positions of the negative electrode active material layer (220) during the charge and discharge process. If the negative electrode active material layer (220) does not include a binder, the negative electrode active material layer (220) can be easily separated from the negative electrode current collector (210). As the negative electrode active material layer (220) is detached from the negative electrode current collector (210), the negative electrode current collector (210) can come into contact with the solid electrolyte layer at the exposed portion, thereby increasing the possibility of a short circuit occurring.

[0074] The negative electrode active material layer (220) is manufactured, for example, by providing a mixture in which the materials constituting the negative electrode active material layer (220) are dispersed onto the negative electrode current collector (210). Since a binder is included in the materials constituting the negative electrode active material layer (220), stable dispersion of the negative electrode active material in the mixture is possible. 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 the negative electrode active material) by the binder.

[0075] The negative electrode active material layer (220) may further include other additives in addition to the negative electrode active material and binder. The negative electrode active material layer (220) may further include, for example, fillers, coating agents, dispersants, ion conductive additives, etc.

[0076] The negative electrode active material layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode active material layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode active material layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode active material layer (220) is too thin, lithium dendrites formed between the negative electrode active material layer (220) and the negative electrode current collector (210) may collapse the negative electrode active material layer (220), thereby deteriorating the cycle characteristics of the all-solid-state battery (10). If the thickness of the negative electrode active material layer (220) increases excessively, the energy density of the all-solid-state battery (10) may decrease and the internal resistance of the all-solid-state battery (10) due to the negative electrode active material layer (220) may increase, thereby deteriorating the cycle characteristics of the all-solid-state battery (10).

[0077] If the thickness of the negative electrode active material layer (220) decreases, the charge capacity of the negative electrode active material layer (220) may also decrease, for example. The charge capacity of the negative electrode active material layer (220) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% or less than the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) is, for example, 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% to 10%, 0.1% to 5%, or 0.1% to 2% than the charge capacity of the positive electrode active material layer (120). If the charge capacity of the negative electrode active material layer (220) is excessively small, the thickness of the negative electrode active material layer (220) becomes very thin, and the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) becomes excessively thin may occur. If the charge capacity of the negative electrode active material layer (220) increases excessively, the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (220) increases excessively may occur.

[0078] For example, the charge capacity of the positive electrode active material layer (120) can be obtained by multiplying the charge capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer (120). When the positive electrode active material layer (120) includes several types of positive electrode active materials, the [charge capacity density Х mass] value is calculated for each positive electrode active material, and the sum of these values ​​of the positive electrode active materials is the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (220) can also be calculated in the same way. That is, the charge capacity of the negative electrode active material layer (220) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer (220). When the negative electrode active material layer (220) includes several types of negative electrode active materials, the [charge capacity density Х mass] value is calculated for each negative electrode active material, and the sum of these values ​​of the negative electrode active materials is the capacity of the negative electrode active material layer (220). Here, the charge capacity density of the positive electrode active material and the negative electrode active material may be an estimated capacity using an all-solid-state half-cell using lithium metal as a counter electrode. The charge capacity of the positive electrode active material layer (120) and the negative electrode active material layer (220) can be directly measured by measuring the charge capacity using the all-solid-state half-cell. The charge capacity density can be obtained by dividing the measured charge capacity by the mass of each active material. Meanwhile, in the present specification, the “charge capacity” of the positive electrode active material layer (120) and the negative electrode active material layer (220) means the initial charge capacity measured at the time of the first cycle charge.

[0079] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the negative electrode active material layer (220) and the solid electrolyte layer (300).

[0080]

[0081] A solid electrolyte layer (300) may be provided between the positive electrode layer (100) and the negative electrode layer (200). The solid electrolyte layer (300) may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The solid electrolyte in the solid electrolyte layer (300) may be the same as or different from the solid electrolyte included in the positive electrode active material layer (120) described above.

[0082] In one embodiment, the solid electrolyte included in the solid electrolyte layer (300) may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may be, for example, a sulfide-based solid electrolyte material that includes at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material that includes 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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, and the like, but is not limited thereto. For example, the binder may include at least one selected from the group consisting of styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode active material layer (220).

[0087]

[0088] Figure 2 is a cross-sectional view of an all-solid-state battery (10) according to another embodiment of the present invention.

[0089] 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).

[0090] 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).

[0091]

[0092] 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.

[0093] 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).

[0094] 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).

[0095] 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).

[0096] 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.

[0097]

[0098] 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.

[0099] 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 first coating layer (220). The thickness of the lithium metal layer (400) may further increase when the all-solid-state battery (10) is charged. The first 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).

[0100] 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.

[0101] 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).

[0102]

[0103] FIG. 6 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention.

[0104] 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.

[0105]

[0106] Hereinafter, the all-solid-state battery and the positive electrode included therein in the embodiments of the present invention will be described in more detail.

[0107] FIGS. 7 and 8 are cross-sectional views showing a positive electrode for an all-solid-state battery according to one embodiment of the present invention.

[0108] Referring to FIG. 7, the positive electrode (100) for an all-solid-state battery according to the present invention may include a positive electrode current collector (110), an active material layer (120) disposed on the positive electrode current collector (110), and a porous film (PW) disposed within the positive electrode active material layer (120).

[0109] The positive electrode active material layer (120) includes a positive electrode active material and may further include a binder and / or a conductive material. The description of the positive electrode active material, binder, and conductive material included in the positive electrode active material layer (120) may be the same as that described above with respect to FIG. 1.

[0110] The porous film (PW) may include a plurality of pores. For example, the porous film (PW) may have a porosity of 50% to 99%, 60% to 95%, or 70% to 90%. The pore size of the porous film (PW) may be 50 nm to 500 nm, or 100 nm to 300 nm. When the porosity and pore size of the porous film (PW) satisfy the numerical ranges described above, the positive electrode active material can easily penetrate into the porous film (PW), and the porous film can retain a sufficient amount of the active material therein to function as a positive electrode self-supporting membrane.

[0111] The porous film (PW) may have a thin thickness. The thickness of the porous film (PW) may be 5 μm to 20 μm, 5 μm to 15 μm, or 8 μm to 10 μm. When the thickness of the porous film (PW) satisfies the numerical range described above, the loading level of the positive electrode can be improved without hindering the movement of lithium ions within the positive electrode.

[0112] The weight of the porous film (PW) is 2 g / m 2 4g / m 2 It can be. For example, the weight of the porous film (PW) is 2.5 g / m 2 3.5g / m 2 It could be.

[0113] The tensile strength of the porous film (PW) may be 0.1 N / mm to 0.2 N / mm. For example, the tensile strength of the porous film (PW) may be 0.1 N / mm to 0.13 N / mm.

[0114] The air permeability per thickness of the porous film (PW) may be 0.1 sec / 100 ml to 1 sec / 100 ml. For example, the air permeability per thickness of the porous film (PW) may be 0.1 sec / 100 ml to 0.5 sec / 100 ml.

[0115] The porous film (PW) may include at least one selected from the group consisting of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, and polyphenylene sulfide. For example, the polyester may include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like.

[0116] In one embodiment, the porous film (PW) may be a porous nonwoven fabric.

[0117]

[0118] Referring to FIG. 8, the positive electrode active material layer (120) can be divided into a plurality of sub-layers according to the arrangement positions based on the porous film (PW) and the positive electrode current collector (110). Specifically, the positive electrode active material layer (120) can include a first sub-layer (P1) on the positive electrode current collector (110), a second sub-layer (P2) arranged between the first sub-layer (P1) and the porous film (PW), and a third sub-layer (P3) arranged on the porous film (PW). The third sub-layer (P3) can be spaced apart from the second sub-layer (P2) with the porous film (PW) interposed therebetween.

[0119] The second sub-layer (P2) and the third sub-layer (P3) may have different thicknesses. In one embodiment, the ratio (d / c) of the thickness (d) of the third sub-layer (P3) to the thickness (c) of the second sub-layer (P2) may be 2 to 10, 3 to 10, or 4 to 7. Specifically, the thickness (c) of the second sub-layer (P2) may be 5 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm. The thickness (d) of the third sub-layer (P3) may be 40 μm to 80 μm, 40 μm to 70 μm, or 50 μm to 70 μm.

[0120] The first sub-layer (P1) may have an integral shape with the second sub-layer (P2). No separate interface is provided between the first sub-layer (P1) and the second sub-layer (P2), and the active material included in the first sub-layer (P1) and the active material included in the second sub-layer (P2) may be mixed to provide a mixed active material layer having an integral shape. Although not specifically illustrated, the active material included in the second sub-layer (P2) may be mixed with active materials that have penetrated into the pores of the porous film (PW) to provide a mixed active material layer having an integral shape. The active material included in the third sub-layer (P3) may be mixed with active materials that have penetrated into the pores of the porous film (PW) to provide a mixed active material layer having an integral shape. That is, in the positive electrode active material layer (120), the active material included in the first sub-layer (P1), the active material included in the second sub-layer (P2), the active material included in the third sub-layer (P3), and the active material permeating the pores in the porous film (PW) can be mixed with each other to provide a single mixed active material layer having an integral shape.

[0121] Referring back to FIG. 7, the positive electrode active material layer (120) may have a first thickness (a), and the porous film (PW) may be positioned within the positive electrode active material layer at a first distance (b) from the positive electrode current collector (110). The first thickness (a) and the first distance (b) may satisfy the relationship of Equation 1 below. The unit of the first thickness (a) and the first distance (b) may be micrometer (μm).

[0122] [Formula 1]

[0123] 0.5 < (b / a) < 0.8

[0124] In other words, the distance (b) between the porous film (PW) and the positive electrode current collector (110) may be 50% or more and 80% or less of the total thickness (a) of the positive electrode active material layer (120). In one embodiment, the distance (b) between the porous film (PW) and the positive electrode current collector (110) may be 55% or more and 75% or less, or 55% or more and 70% or less, of the total thickness (a) of the positive electrode active material layer (120). When the distance (b) between the porous film (PW) and the positive electrode current collector (110) and the thickness (a) of the positive electrode active material layer (120) satisfy the relationship of Equation 1, the all-solid-state battery can have excellent life characteristics and implement high current density.

[0125] In one embodiment, the first thickness (a) of the positive electrode active material layer (120) may be 100 μm to 200 μm, 120 μm to 180 μm, or 140 μm to 150 μm. In one embodiment, the first distance (b) between the porous film (PW) and the positive electrode current collector (110) may be 50 μm to 160 μm, 70 μm to 100 μm, or 80 μm to 90 μm.

[0126] The positive electrode (100) for an all-solid-state battery according to embodiments of the present invention may have a high loading level since the positive electrode active material layer (120) includes a porous film (PW) disposed within the positive electrode active material layer (120), and the positive electrode active material layer (120) includes a plurality of sub-layers disposed based on the upper and lower portions of the porous film (PW). Here, the “loading level” may be a factor designed by considering the amount of active material per unit area of ​​the electrode, the diffusion coefficient of lithium ions, conduction between particles, and the path to the current collector. In the positive electrode for an all-solid-state battery of one embodiment, the loading level of the positive electrode active material layer (120) is 35 mg / cm 2 It can be more than 40mg / cm2, for example. 2 or more than 45 mg / cm 2 It could be strange.

[0127]

[0128] Fig. 9 is a cross-sectional view illustrating a positive electrode for an all-solid-state battery according to another embodiment of the present invention. In this embodiment, detailed descriptions of technical features that overlap with those previously described with reference to Figs. 7 and 8 will be omitted, and differences will be described in detail.

[0129] Referring to FIG. 9, a positive electrode (100) for an all-solid-state battery according to one embodiment includes a positive electrode current collector (110) and a positive electrode active material layer (120) on the positive electrode current collector (120), and may include a porous film (PW) disposed within the positive electrode active material layer (120). Meanwhile, the porous film (PW) may include a plurality of sub-porous films.

[0130] Specifically, in an all-solid-state battery positive electrode (100) according to one embodiment, a first sub-porous film (PW-a) and a second sub-porous film (PW-b) may be provided inside a positive electrode active material layer (120). The second sub-porous film (PW-b) may be spaced apart from the positive electrode current collector (110) with the first sub-porous film (PW-a) interposed therebetween.

[0131] Each of the plurality of sub-porous films (PW-a, PW-b) is disposed within the positive electrode active material layer (120), and the positive electrode active material included in the positive electrode active material layer (120) may be permeated into the interior of each of the sub-porous films (PW-a, PW-b).

[0132] The first sub-layer (P1) may have an integral shape with the second sub-layer (P2). No separate interface is provided between the first sub-layer (P1) and the second sub-layer (P2), and the active material included in the first sub-layer (P1) and the active material included in the second sub-layer (P2) may be mixed to provide a single mixed active material layer having an integral shape. The third sub-layer (P3) may have an integral shape with the fourth sub-layer (P4). No separate interface is provided between the third sub-layer (P3) and the fourth sub-layer (P4), and the active material included in the third sub-layer (P3) and the active material included in the fourth sub-layer (P4) may be mixed to provide a single mixed active material layer having an integral shape.

[0133] Although not specifically illustrated, the active material included in the second sub-layer (P2) and the active material included in the third sub-layer (P3) can be mixed with the active materials that have penetrated the pores in the first sub-porous film (PW-a) to provide a mixed active material layer having an integral shape. The active material included in the fourth sub-layer (P4) and the active material included in the fifth sub-layer (P5) can be mixed with the active materials that have penetrated the pores in the second sub-porous film (PW-b) to provide a mixed active material layer having an integral shape. That is, in the positive electrode active material layer (120), the active materials included in each of the first to fifth sub-layers (P1) to (P5) and the active materials that have penetrated the pores of each of the first sub-porous film (PW-a) and the second sub-porous film (PW-b) can be mixed with each other to provide a single mixed active material layer having an integral shape.

[0134]

[0135] Hereinafter, a method for manufacturing an all-solid-state battery positive electrode according to one embodiment will be described. The method for manufacturing an all-solid-state battery positive electrode according to one embodiment may include coating a first preliminary active material layer on a positive electrode substrate, disposing a composite layer including a porous film on the first preliminary active material layer, and sequentially pressing the positive electrode substrate, the first preliminary active material layer, and the composite layer as a whole.

[0136] FIGS. 10A and 10B are cross-sectional views of one step of forming a composite layer according to one embodiment of the present invention.

[0137] Referring to FIGS. 10a and 10b, a pre-porous film (PWA) can be provided on a release film (RF).

[0138] The release film (RF) can be placed on a plane defined by a first direction (D1) and a second direction (D2). The second direction (D2) can intersect the first direction (D1). A pre-porous film (PWA) can be provided on the release film (RF). The pre-porous film (PWA) can be laminated on the release film (RF) along a third direction (D3). The third direction (D3) can be a direction intersecting each of the first direction (D1) and the second direction (D2). As described above, the pre-porous film (PWA) can include a plurality of pores. The size of the pores of the pre-porous film (PWA) can be 50 nanometers or more and 500 nanometers or less. The pre-porous film (PWA) can have a thin thickness. The thickness of the pre-porous film (PWA) can be 5 μm to 20 μm. For example, the thickness of the pre-porous film may be 5 μm to 15 μm, or 8 μm to 12 μm. In one embodiment, the pre-porous film (PWA) may be a porous nonwoven fabric.

[0139] As shown in Fig. 10a, a binder (BD) may be laminated onto a pre-porous film (PWA). The pre-porous film (PWA) includes a first region (A1) where the binder (BD) is laminated, and a second region (A2) where the binder (BD) does not overlap. The first region (A1) may be located on both sides of the pre-porous film. The second region (A2) may be a region remaining from the first region (A1).

[0140] A binder (BD) can be formed by coating on the first region (A1) of the pre-porous film (PWA) and then curing. The binder (BD) can include at least one of a thermosetting resin and an ultraviolet-curable resin.

[0141] After the binder (BD) is formed, a positive electrode active material (AM) may be provided on the pre-porous film (PWA). The positive electrode active material (AM) may be provided on the second region (A2) of the pre-porous film (PWA), and the positive electrode active material (AM) may be provided in the form of a slurry.

[0142] The positive electrode active material slurry may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder. The description of the positive electrode active material, the solid electrolyte, the conductive material, and the binder included in the positive electrode active material slurry may be the same as described in FIG. 1. In one embodiment, the positive electrode active material slurry may include, as a binder, at least one selected from the group consisting of styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0143] After the positive active material (AM) is coated on the pre-porous film (PWA), the provided positive active material (AM) can be cured.

[0144] The positive active material (AM) provided on the second region (A2) of the pre-porous film (PWA) can penetrate into the interior of the pre-porous film (PWA). That is, in the step of providing the positive active material (AM) on the second region (A2), the positive active material (AM) can penetrate into the pores of the pre-porous film (PWA). The positive active material (AM) can penetrate into the pores of the pre-porous film (PWA), thereby forming a porous film (PW) in which the positive active material (AM) is filled within the pores.

[0145] Meanwhile, after the positive active material (AM) is coated and penetrates into the pre-porous film (PWA), at least a portion of the second region (A2) of the porous film (PW) may be separated from the release film (RF). Some of the positive active material (AM) may migrate through the pores of the porous film (PW) to form a second pre-active material layer (PA2) between the porous film (PW) and the release film (RF). Some of the positive active material (AM) may form a third pre-active material layer (PA3) on the porous film (PW) without passing through the porous film (PW).

[0146] The thickness of the second pre-active material layer (PA2) that has moved through the pores of the porous film (PW) may be smaller than the thickness of the third pre-active material layer (PA3) that has not passed through the porous film (PW). In one embodiment, the ratio of the thickness of the third pre-active material layer (PA3) to the thickness of the second pre-active material layer (PA2) may be 2 to 10, 3 to 10, or 4 to 7.

[0147] Although not specifically illustrated, the positive electrode active material included in each of the second preliminary active material layer (PA2) and the third preliminary active material layer (PA3) may have an integral shape with the active material impregnated inside the porous film (PW). After the positive electrode active material (AM) is coated and cured, a composite layer (CMM) including the second preliminary active material layer (PA2), the third preliminary active material layer (PA3), and the porous film (PW) interposed therebetween may be formed.

[0148] The release film (RF) may be subsequently peeled off. For example, the release film (RF) may be separated from the composite layer (CMM). Accordingly, the release film (RF) may include a material that is separable from the composite layer (CMM). For example, the release film (RF) may include at least one selected from the group consisting of polyethylene terephthalate, polypropylene, polymethyl pentene, and copolymers thereof.

[0149] The porous film (PW) included in the composite layer (CMM) may have a self-standing film form. A self-standing film may refer to a thin film or film that maintains a certain shape on its own without being supported by another substrate, etc. In one embodiment, the composite layer (CMM) may be in a form in which the release film (RF), the binder (BD), and the preliminary porous film (PW-a) corresponding to the first region (A1) among the configurations illustrated in FIG. 10b are removed.

[0150] The thickness of the composite layer (CMM) can be uniform. The thickness of the composite layer (CMM) can be 50 µm to 500 µm. For example, the thickness of the composite layer (CMM) can be 60 µm to 300 µm, 80 µm to 200 µm, or 100 µm to 200 µm.

[0151]

[0152] Figures 11 to 13 are cross-sectional views showing each step of an electrode manufacturing method according to one embodiment of the present invention.

[0153] Referring to FIG. 11, a first preliminary active material layer (PA1) may be formed on a positive electrode substrate (110). The first preliminary active material layer (PA1) may be formed on only one side of the positive electrode substrate (110). The first preliminary active material layer (110) may be formed by coating a positive electrode active material on one side of the positive electrode substrate (110) and then drying the coating. Meanwhile, the positive electrode substrate (110) illustrated in FIG. 11 and the like may correspond to the positive electrode current collector (110) described in FIGS. 7 to 9 and the like, and the first preliminary active material layer (PA1) may correspond to the first sub-layer (P1) described in FIG. 8.

[0154] Referring to FIGS. 11 and 12, a composite layer (CMM) may be provided on a first preliminary active material layer (PA1) formed on a positive electrode substrate (110). In other words, the composite layer (CMM) may be formed by the method described above with reference to FIGS. 10A and 10B and may be provided on a first preliminary active material layer (PA1) disposed on one surface of the electrode substrate (110). When the composite layer (CMM) is provided on the first preliminary active material layer (PA1), a second preliminary active material layer (PA2) may be provided adjacent to the first preliminary active material layer (PA1).

[0155] Referring to FIGS. 12 and 13, after the composite layer (CMM) is provided, the sequentially laminated positive electrode substrate (110), the first preliminary active material layer (PA1), and the composite layer (CMM) can be pressed together. The sequentially laminated electrode substrate (110), the first preliminary active material layer (PA1), and the composite layer (CMM) can be pressed by a pressurizing unit (PRU).

[0156] The pressurizing unit (PRU) may include a pressurizing roller. The pressurizing unit (PRU) may roll an electrode substrate (COL), a first pre-active material layer (PA1) on the electrode substrate (COL), and a composite layer (CMM) on the first pre-active material layer (PA1).

[0157] After the pressurizing process by the pressurizing unit (PRU), an active material layer (AML) can be formed. The active material layer (AML) can include a plurality of sub-layers (P1, P2, P3). The active material layer (AML) can include a first sub-layer (P1) disposed on one surface of the electrode substrate (COL), a second sub-layer (P2) disposed between the first sub-layer (P1) and a porous film (PW), and a third sub-layer (P3) disposed on the porous film (PW). The third sub-layer (P3) can be spaced apart from the second sub-layer (P2) with the porous film (PW) interposed therebetween. Meanwhile, the first sub-layer (P1) can be derived from the first preliminary active material layer (PA1), the second sub-layer (P2) can be derived from the second preliminary active material layer (PA2), and the third sub-layer (P3) can be derived from the third preliminary active material layer (PA3).

[0158] The first sub-layer (P1) may have an integral shape with the second sub-layer (P2). No separate interface is provided between the first sub-layer (P1) and the second sub-layer (P2), and the active material included in the first sub-layer (P1) and the active material included in the second sub-layer (P2) may be mixed to provide a single mixed active material layer having an integral shape. The first sub-layer (P1) and the second sub-layer (P2) are derived from the first preliminary active material layer (PA1) and the second preliminary active material layer (PA2), which are different layers, respectively, but may be mixed to have an integral shape through the above-described pressing process.

[0159] Although not specifically illustrated, the active material included in the second sub-layer (P2) can be mixed with the active materials that have penetrated the pores in the porous film (PW) to provide a mixed active material layer having an integral shape. The active material included in the third sub-layer (P3) can be mixed with the active materials that have penetrated the pores in the porous film (PW) to provide a mixed active material layer having an integral shape. That is, in the active material layer (AML), the active material included in the first sub-layer (P1), the active material included in the second sub-layer (P2), the active material included in the third sub-layer (P3), and the active material that has penetrated the pores in the porous film (PW) can be mixed with each other to provide a single mixed active material layer having an integral shape.

[0160]

[0161] 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.

[0162]

[0163] Example 1

[0164] (Polar electrode manufacturing)

[0165] LiNi0.8Co0 as a cathode active material. 15 Mn0. 05 O2 (NCM) powder was prepared. A crystalline argyrodite-based solid electrolyte (Li6PS5Cl) was prepared as a solid electrolyte, a polyvinylidene fluoride (PVdF) binder was prepared as a binder, and carbon nanofibers (CNF) were prepared as a conductive material. These materials were mixed in an N-methyl pyrrolidone solvent at a weight ratio of positive electrode active material: solid electrolyte: conductive material: binder = 85:13.5:0.5:1 to prepare a positive electrode active material slurry.

[0166] The above positive electrode active material slurry was coated on an aluminum positive electrode current collector, dried, and pressed to manufacture a first positive electrode plate.

[0167] Separately, the above-mentioned positive electrode active material slurry was coated on a porous nonwoven fabric having a thickness of 10 μm to prepare a positive electrode active material composite layer in the form of a self-standing film. The prepared positive electrode active material composite layer was laminated on a primary positive electrode plate such that the porous nonwoven fabric was positioned close to the positive electrode current collector, and then rolled to form a positive electrode.

[0168] Rolling is performed using a rolling roll at 25℃, and the pre-pressure of the rolling roll is controlled to approximately 2.3 tons. The gap between the upper and lower rolls constituting the rolling roll is adjusted to 0 to maximize the rolling of the positive electrode, thereby minimizing the thickness of the positive electrode after rolling and forming a high composite density. The loading level of the positive electrode active material arranged on one side of the current collector is 45 mg / cm. 2 It was manufactured to be like this.

[0169] The total thickness of the manufactured positive electrode was 150 μm, and the distance between the positive electrode collector and the porous nonwoven fabric was 90 μm.

[0170] (Manufacturing of solid electrolyte layer)

[0171] A solid electrolyte slurry was prepared by adding argyrodite-type solid electrolyte Li6PS5Cl to an isobutyl isobutylate binder solution containing a butyl acrylate polymer (the mixing ratio of the solid electrolyte and the binder was 98.7:1.3 by weight). The prepared solid electrolyte slurry was applied to a polytetrafluoroethylene film and dried at 60°C for 2 hours to prepare a solid electrolyte layer having a thickness of 100 μm.

[0172] (Cathode manufacturing)

[0173] A slurry for a cathode coating layer was prepared by mixing 90 wt% of Ag nanoparticles (D50: 60 nm) and 10 wt% of carbon black in a water solvent. The carbon black was a mixture of single particles with a particle size of 38 nm and secondary particles, and the secondary particles were formed by assembling primary particles with a particle size of 76 nm and secondary particles with a particle size of 275 nm. The slurry was coated on a stainless steel foil current collector and then dried to prepare a cathode including a 12 μm thick cathode coating layer and a 10 μm thick current collector.

[0174]

[0175] Example 2

[0176] A cathode and an all-solid-state battery were manufactured in the same manner as in Example 1, except that the amount of cathode active material slurry was reduced and the amount of slurry of the self-supporting cathode active material composite layer was increased when manufacturing the first cathode plate.

[0177] The total thickness of the manufactured positive electrode was 145 um, and the distance between the positive electrode collector and the porous nonwoven fabric was 85 um.

[0178]

[0179] Comparative Example 1

[0180] In the manufacture of the positive electrode, the positive electrode was manufactured in the same manner as in Example 1, except that the first positive electrode plate manufactured by coating the positive electrode active material slurry on an aluminum positive electrode collector, drying, and pressing was used as the positive electrode, excluding the step of manufacturing a composite layer in the form of a self-supporting film. The loading level of the manufactured positive electrode was 25 mg / cm 2 It was.

[0181] Afterwards, an all-solid-state battery was manufactured using the same method as in the example.

[0182]

[0183] Comparative Example 2

[0184] In the manufacture of the positive electrode, a composite layer of positive electrode active material in the form of a self-standing film is laminated and rolled on the first positive electrode plate so that the porous nonwoven fabric is positioned far from the positive electrode current collector, and the loading level is 45 mg / cm. 2 The anode was manufactured in the same manner as in Example 1, except that it was made to be .

[0185] The total thickness of the manufactured positive electrode was 150 μm, and the distance between the positive electrode collector and the porous nonwoven fabric was 140 μm.

[0186] Afterwards, an all-solid-state battery was manufactured using the same method as in the example.

[0187]

[0188] Evaluation Example: Evaluation of All-Solid State Battery Life Characteristics

[0189] The room temperature life characteristics of the complete cells manufactured according to Example 1, Example 2, and Comparative Example 2 were evaluated, and the results are shown in Table 1 and Figure 14 below.

[0190] The solid-state battery according to the comparative example was 1) charged (0.33C CC / CV charge 4.25V 0.05C cut) and discharged (0.33C CC discharge 3.0V cut) as the first cycle, and 2) charged (1.0C CC / CV charge 4.25V 0.05C cut) and discharged (0.5C CC discharge 3.0V cut) as the second cycle, and the cycles were checked until the capacity retention rate became 80%, and charge and discharge were performed. The Nth capacity retention rate was calculated using the following mathematical equation 1.

[0191] <Mathematical Formula 1>

[0192] Capacity retention rate [%] = [Discharge capacity in the Nth cycle / Discharge capacity in the first cycle] × 100

[0193]

[0194] Life evaluation (SOH 80%) Example 1100 cyc Example 2102 cyc Comparative example 225 cyc

[0195] Referring to Table 1 and Figure 14, it can be confirmed that the all-solid-state battery according to the embodiment has a superior capacity retention rate compared to the all-solid-state battery according to the comparative example. Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that such modifications also fall within the scope of the present invention.

Claims

1. Bipolar collector; a positive electrode active material layer on the positive electrode current collector; and Including a porous film disposed within the above positive electrode active material layer, The above positive electrode active material layer has a first thickness (a), The above porous film is positioned within the positive electrode active material layer at a first distance (b) from the positive electrode current collector, An all-solid-state battery positive electrode in which the first thickness (a) and the first distance (b) satisfy the relationship of Equation 1 below: [Formula 1] 0.5 < (b / a) < 0.8 2. In paragraph 1, An all-solid-state battery positive electrode in which the first thickness (a) and the first distance (b) satisfy the relationship of Equation 2 below: [Formula 2] 0.55 < (b / a) < 0.7 3. In paragraph 1, The above positive electrode active material layer A first sub-layer disposed on the above positive electrode collector, a second sub-layer disposed between the first sub-layer and the porous film, and An all-solid-state battery positive electrode comprising a third sub-layer disposed on the porous film.

4. In paragraph 1, The above porous film is an all-solid-state battery positive electrode comprising at least one selected from the group consisting of polyester, polyethylene terephthalate, polypropylene, and polyethylene.

5. In paragraph 1, An all-solid-state battery positive electrode having a porous film having a thickness of 5 μm to 15 μm.

6. In paragraph 1, An all-solid-state battery positive electrode having a first thickness of 120 μm to 180 μm.

7. In paragraph 1, The above positive electrode active material layer includes a positive electrode active material, The loading level of the above positive electrode active material is 35 mg / cm 2 Ideal all-solid-state battery cathode.

8. In paragraph 7, The above positive electrode active material layer further includes a binder, A positive electrode for an all-solid-state battery, wherein the binder comprises at least one selected from the group consisting of styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

9. In paragraph 7, An all-solid-state battery positive electrode, wherein the positive electrode active material layer further comprises a solid electrolyte.

10. In paragraph 1, A positive electrode for an all-solid-state battery, wherein the positive electrode active material layer is provided only on one surface of the positive electrode current collector.

11. The anode according to paragraph 1; a cathode opposite to the anode; and An all-solid-state battery comprising a solid electrolyte layer disposed between the positive electrode and the negative electrode.

12. In paragraph 11, The above cathode comprises a metal and a carbon-based material, The metal comprises at least one selected from the group consisting of Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt and Pd, The above carbon-based material is an all-solid-state battery comprising crystalline carbon, amorphous carbon or a combination thereof.

13. In paragraph 11, An all-solid-state battery wherein the above solid electrolyte layer includes an argyrodite-based solid electrolyte.

14. Forming a first preliminary active material layer on a positive electrode substrate; Placing a composite layer including a porous film on the first preliminary active material layer; and Including pressing the sequentially laminated positive electrode substrate, the first preliminary active material layer, and the composite layer as one body, What forms the above composite layer is Providing a pre-porous film; and Providing a positive electrode active material on the above-mentioned preparatory porous film to form a porous film and a preparatory composite active material layer, A method for manufacturing a positive electrode for an all-solid-state battery, wherein in the above composite layer, the porous film is disposed within the preliminary composite active material layer.

15. In paragraph 14, In pressurizing the above positive electrode substrate, the first preliminary active material layer, and the composite layer as a whole, A method for manufacturing a positive electrode for an all-solid-state battery, wherein the first preliminary active material layer and the preliminary composite active material layer are mixed to have an integral shape to form a single mixed active material layer.

16. In paragraph 15, The above mixed active material layer has a first thickness (a), The above porous film is positioned within the mixed active material layer at a first distance (b) from the positive electrode substrate, A method for manufacturing an all-solid-state battery positive electrode in which the first thickness (a) and the first distance (b) satisfy the relationship of the following equation 1: [Formula 1] 0.5 < (b / a) < 0.8 17. In paragraph 14, In forming the above porous film, A method for manufacturing a positive electrode for an all-solid-state battery, wherein the positive electrode active material penetrates into the pores provided in the preparatory porous film.

18. In paragraph 14, A method for manufacturing a positive electrode for an all-solid-state battery, wherein the thickness of the above-mentioned preliminary porous film is 5 ㎛ to 15 ㎛.

19. In paragraph 14, A method for manufacturing an all-solid-state battery positive electrode, wherein the size of the pores provided in the above-mentioned preparatory porous film is 50 nm to 500 nm.

20. In paragraph 14, A method for manufacturing an all-solid-state battery positive electrode, wherein the porosity of the above-mentioned preliminary porous film is 50% to 99%.

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