Solid electrolyte membrane, all-solid-state battery comprising same, and solid electrolyte membrane manufacturing method

Abstract

The present invention relates to a solid electrolyte membrane for an all-solid-state battery, and a solid electrolyte membrane manufacturing method, and, more specifically, comprises a sulfide-based solid electrolyte, a first binder, a second binder and a lithium salt. The second binder is different from the first binder, the first binder forms a composite with the lithium salt, and the sulfide-based solid electrolyte comprises first particles and second particles. The second binder is bound to the surface of each of the first particle and the second particle, and the first binder is bound to the second binder on the first particles and the second binder on the second particles.

Description

Solid electrolyte membrane, all-solid-state battery including the same, and method for manufacturing the solid electrolyte membrane

[0001] The present invention relates to a solid electrolyte membrane, an all-solid-state battery including the same, and a method for manufacturing the solid electrolyte membrane.

[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 solid electrolyte membrane having excellent flexibility and excellent ionic conductivity.

[0007] Another problem to be solved by the present invention is to provide a method for manufacturing a solid electrolyte membrane having excellent flexibility and excellent ionic conductivity.

[0008]

[0009] According to the concept of the present invention, a solid electrolyte membrane may include a sulfide-based solid electrolyte, a first binder, a second binder, and a lithium salt. The second binder is different from the first binder, the first binder forms a complex with the lithium salt, and the sulfide-based solid electrolyte may include first particles and second particles. The second binder may bond to the surfaces of each of the first particles and the second particles, and the first binder may bond to the second binder on the first particles and the second binder on the second particles.

[0010]

[0011] According to another concept of the present invention, a solid electrolyte membrane may include a sulfide-based solid electrolyte, a first binder, a second binder, and a lithium salt. The first binder forms a complex with the lithium salt, the first binder includes an acrylic polymer, and the second binder may include at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

[0012]

[0013] According to another concept of the present invention, a method for manufacturing a solid electrolyte membrane may include forming a first mixed solution by mixing a first binder and a lithium salt; forming a first slurry by mixing a sulfide-based solid electrolyte and a second binder; forming a second slurry by adding the first mixed solution to the first slurry; and forming a first membrane by applying the second slurry to a substrate. The first binder may include an acrylic polymer, and the second binder may include at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

[0014]

[0015] The solid electrolyte membrane according to the present invention may include two different binders and a lithium salt. This enhances the flexibility and robustness of the solid electrolyte membrane, improves ionic conductivity, and prevents short circuits during high-speed charging.

[0016] By using the method for manufacturing a solid electrolyte membrane according to the present invention, a solid electrolyte membrane with improved flexibility and enhanced ionic conductivity and rigidity can be manufactured.

[0017]

[0018] Figure 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0019] Figure 2 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0020] 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.

[0021] Figure 5 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention.

[0022] 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.

[0023] Figure 7 is an enlarged view of area M of Figure 1.

[0024] Figure 8 is an enlarged view of area N of Figure 7.

[0025] Figure 9 is a flowchart illustrating a method for manufacturing a solid electrolyte membrane according to embodiments of the present invention.

[0026] Figures 10 to 13 are schematic diagrams each illustrating each step of the above manufacturing method.

[0027] Fig. 14 is a drawing showing the state of a solid electrolyte membrane after roll pressing according to one embodiment of the present invention.

[0028]

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0034] 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.

[0035] Figure 1 is a cross-sectional view of an all-solid-state battery (10) according to one embodiment of the present invention.

[0036] 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).

[0037] 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.

[0038] 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.

[0039] 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).

[0040] The cathode active material layer (120) may include a cathode active material, a solid electrolyte, a conductive material, and a binder.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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).

[0048] 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.

[0049] 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.

[0050] Alternatively, the solid electrolyte may be the same as the solid electrolyte (SE) included in the solid electrolyte layer (300) described later.

[0051] 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.

[0052] The solid electrolyte included in the positive electrode active material layer (120) may have a median particle size (D50) smaller than the solid electrolyte (SE) 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 (SE) 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.

[0053] The positive electrode 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 positive electrode active material and the solid electrolyte.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] For example, the cathode active material layer (120) may further include a lithium salt. The lithium salt may be the same as or different from the lithium salt (LTS) included in the solid electrolyte layer (300) described below.

[0060]

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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).

[0075] 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.

[0076] 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.

[0077] 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).

[0078] Referring to FIG. 1, a solid electrolyte layer (300) is positioned between the positive electrode layer (100) and the negative electrode layer (200). The solid electrolyte layer (300) will be described later with reference to FIG. 7.

[0079]

[0080] Figure 2 is a cross-sectional view of an all-solid-state battery (10) according to another embodiment of the present invention.

[0081] 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).

[0082] 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).

[0083]

[0084] 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.

[0085] 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).

[0086] 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).

[0087] 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).

[0088] 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.

[0089]

[0090] 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.

[0091] 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).

[0092] 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.

[0093] 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).

[0094]

[0095] FIG. 6 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention.

[0096] 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.

[0097]

[0098] Fig. 7 is an enlarged view of a cross-section of a solid electrolyte layer (300) according to one embodiment of the present invention. Fig. 7 is an enlarged view of area M of Fig. 1.

[0099] Referring to FIGS. 1 and 7, the solid electrolyte layer (300) may include a solid electrolyte (SE), a first binder (BND1), a second binder (BND2), and a lithium salt. The first binder (BND1) and the lithium salt (LTS) may exist as a complex (CPX) within the solid electrolyte layer (300). The solid electrolyte layer (300) may be manufactured by the method of FIG. 8. The solid electrolyte layer (300) may include a solid electrolyte membrane, which will be described later.

[0100] The solid electrolyte layer (300) includes a solid electrolyte (SE) with excellent lithium ion conductivity characteristics.

[0101] The solid electrolyte layer (300) of one embodiment may include a sulfide-based solid electrolyte. That is, the solid electrolyte (SE) 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 containing Li2S-P2S5 to form a solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0102] 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.

[0103] 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.

[0104] 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.

[0105]

[0106] The solid electrolyte layer (300) may further include a complex (CLX) of a first binder (BND1) and a lithium salt (LTS). The first binder (BND1) included in the solid electrolyte layer (300) may include an acrylic polymer. For example, the first binder (BND1) may include at least one selected from the group consisting of acrylate rubber, acrylonitrile rubber, polyacrylonitrile, polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, and polyacrylic acid. The first binder (BND1) may have a particle shape such as a dot shape, a spherical shape, or an oblong spherical shape.

[0107] The lithium salt (LTS) included in the solid electrolyte layer (300) can be represented by the following structural formula 1.

[0108] [Structural formula 1]

[0109]

[0110] In the above structural formula 1, R1 and R2 may be the same or different from each other. For example, the size of R1 and the size of R2 may be the same or different from each other. The size may refer to the size of the atoms constituting the substituent, the length of the chain, and / or the volume of the substituent.

[0111] For example, each of R1 and R2 may include a fluorine (F) element. For example, R1 may include the following structural formula 2.

[0112] [Structural formula 2]

[0113]

[0114] In the above structural formula 2, n may be an integer between 1 and 10. For example, R1 may include one selected from the group consisting of -F, -CF3, -CF2CF3, -CF2CF2CF3, -CF2CF2CF2CF3, -CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF2CF3, and -CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3.

[0115] For example, R2 may comprise the following structural formula 3.

[0116] [Structural formula 3]

[0117]

[0118] In the above structural formula 3, the m may be an integer between 1 and 10. For example, R2 may include one selected from the group consisting of -F, -CF3, -CF2CF3, -CF2CF2CF3, -CF2CF2CF2CF3, -CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF2CF3, and -CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3. The m may be the same as or different from the n. That is, the lithium salt (LTS) may have a symmetrical structure or an asymmetrical structure.

[0119] For example, lithium salts (LTS) with a symmetrical structure are LiN(SO2F)2, It may include LiN(SO2CF3)2, LiN(SO2CF2CF3)2, LiN(SO2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, and LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, etc.

[0120] For example, lithium salts (LTS) having an asymmetric structure may include (FSO2)LiN(SO2CF3), etc.

[0121] As another example, the lithium salt (LTS) may include LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, Li(FSO2)2N, Li(CF3SO2)3C, LiSbF6, LiPF3(CF2CF3)3, LiPF3(C2F5)3, LiPF3(CF3)3, LiB(C2O4)2, etc.

[0122] For example, the lithium salt (LTS) may include at least one selected from the group consisting of compounds represented by structural formula 1, LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, Li(FSO2)2N, Li(CF3SO2)3C, LiSbF6, LiPF3(CF2CF3)3, LiPF3(C2F5)3, LiPF3(CF3)3, and LiB(C2O4)2.

[0123] The first binder (BND1) and the lithium salt (LTS) can form a complex (CPX). The complex (CPX) can have a particle shape such as a dot-like shape, a spherical shape, or an oval-shaped shape. Within the complex (CPX), the first binder (BND1) and the lithium salt (LTS) can form an ion-dipole interaction. Specifically, the acrylic functional group present in the first binder (BND1) and the lithium ion of the lithium salt (LTS) can generate an ion-dipole force to form the complex (CPX).

[0124] When the first binder (BND1) exists as a complex (CPX) with a lithium salt (LTS), the glass transition temperature (Tg) may increase compared to when the first binder (BND1) exists alone. The glass transition temperature of the first binder (BND1) may be lower than 0°C, and may be -15°C to -5°C. When a lithium salt (LTS) is added to the first binder (BND1), the glass transition temperature may be 0°C or higher, and may be 5°C to 10°C. The difference in the glass transition temperature of the first binder (BND1) before and after the addition of the lithium salt (LTS) may be 15°C or higher.

[0125] As an example, the glass transition temperature of acrylate rubber may be -3.2°C, and the glass transition temperature of a composite in which acrylate rubber and lithium salt (LiN(SO2CF3)2) are mixed at a weight ratio of 5:2 may be 18.4°C. An increase in the glass transition temperature as described above may mean an increase in mechanical strength.

[0126]

[0127] The solid electrolyte layer (300) can have improved flexibility by including a dot-shaped or spherical first binder (BND1), and can have excellent mechanical strength by including a first binder (BND1) to which a lithium salt (LTS) is added, i.e., a complex (CPX). In other words, the solid electrolyte layer (300) can exhibit excellent flexibility and mechanical strength by including a complex (CPX).

[0128] The weight of the lithium salt (LTS) in the complex (CPX) may be 0.1 to 0.5 relative to the weight of the first binder (BND1) (LTS weight / BND1 weight). When the weight of the lithium salt (LTS) satisfies the above-described range, the solid electrolyte layer (300) may exhibit excellent flexibility and excellent rigidity.

[0129] The solid electrolyte layer (300) may further include a second binder (BND2). The second binder (BND2) included in the solid electrolyte layer (300) may have high dispersibility and high ionicity.

[0130] The second binder (BND2) may be, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, or the like. For example, the second binder (BND2) may include at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

[0131] The second binder (BND2) may have a linear particle shape. Since the second binder (BND2) has a linear particle shape, it can form a linear bond with the solid electrolyte particle (SE). Meanwhile, the composite (CPX) having a spherical particle shape can form a point bond with the second binder (BND2) through hydrogen bonding.

[0132] As an example, referring to FIG. 8, the solid electrolyte layer (300) may include first solid electrolyte particles (SE1) and second solid electrolyte particles (SE2). The second binders (BND2', BND2") may form a line bond with the surfaces of the first solid electrolyte particles (SE1) and the second solid electrolyte particles (SE2), respectively. The composite (CPX) may form a point bond with each of the second binders (BND2', BND2") that form a line bond with the solid electrolyte particles (SE1, SE2).

[0133] A hydrogen bond can be formed between the second binder (BND2', BND2") and the first binder (BND1) that are forming the point bond (between BND2' and BND1, and between BND2" and BND1). The hydrogen bond can be formed between a fluorine, nitrogen, or oxygen element present in the second binder (BND2', BND2") and a hydrogen element present in the first binder (BND1).

[0134] The second binders (BND2', BND2") are connected to the solid electrolyte particles (SE1, SE2) by line contact, and the complex (CPX) is connected to each of the second binders (BND2', BND2") by point contact, so that the first solid electrolyte particle (SE1), the second solid electrolyte particle (SE2), the complex (CPX), and the second binders (BND2', BND2") can be organically connected to each other.

[0135] The solid electrolyte layer (300) can have excellent electrochemical characteristics and flexibility by including a first binder (BND1) with excellent flexibility and a second binder (BND2) with high dispersibility and high ionicity. The solid electrolyte layer (300) can have not only excellent ionic conductivity but also excellent mechanical strength by also including a lithium salt.

[0136] Since the solid electrolyte layer (300) has excellent flexibility, not only warm isostatic press (WIP) but also roll press can be applied when manufacturing an all-solid-state battery. In addition, since the solid electrolyte layer (300) has excellent robustness along with flexibility, the formation of lithium dendrites in the negative electrode can be suppressed, and rapid charging characteristics can be improved.

[0137] The content of the first binder (BND1) may be 0.01 wt% to 10 wt%, 0.5 wt% to 8 wt%, or 0.1 wt% to 5 wt% relative to the total weight of the solid electrolyte layer (300). The content of the second binder (BND2) may be 0.01 wt% to 10 wt%, 0.05 wt% to 8 wt%, or 0.1 wt% to 5 wt% relative to the total weight of the solid electrolyte layer (300). The weight of the second binder (BND2) included in the solid electrolyte layer (300) may be 0.5 to 2, 0.7 to 1.5, or 0.8 to 1.2 relative to the weight of the first binder (BND1).

[0138] The total amount of binder including the first binder (BND1) and the second binder (BND2) may be 1 wt% to 10 wt% relative to the total weight of the solid electrolyte layer (300). Specifically, the total amount of binder may be 2 wt% to 8 wt%, or 3 wt% to 8 wt%.

[0139] When the content of each binder and the total amount of binder satisfy the above range, the solid electrolyte layer (300) can have excellent ionic conductivity while having flexibility.

[0140]

[0141] Solid electrolyte membrane and method for manufacturing the same

[0142] The solid electrolyte membrane may include the above-described solid electrolyte (SE), the above-described first binder (BND1), the above-described second binder (BND2), and the above-described lithium salt (LTS). For example, the solid electrolyte (SE) may be a sulfide-based solid electrolyte.

[0143] The content of the first binder (BND1) may be 0.1 wt% to 4 wt% relative to the total weight of the solid electrolyte membrane. The content of the second binder (BND2) may be 0.1 wt% to 4 wt% relative to the total weight of the solid electrolyte membrane. The total amount of binders including the first binder (BND1) and the second binder (BND2) may be 3 wt% to 8 wt% relative to the total weight of the solid electrolyte membrane.

[0144]

[0145] When the content of each binder and the total amount of binders satisfy the above ranges, the solid electrolyte membrane can have excellent flexibility and excellent ionic conductivity.

[0146] The weight ratio of the first binder (BND1) and the lithium salt (LTS) in the solid electrolyte membrane may be 1:0.1 to 1:0.5. When the weight ratio of the first binder (BND1) and the lithium salt (LTS) satisfies the above-described range, the solid electrolyte membrane can have excellent flexibility and excellent toughness.

[0147]

[0148] A solid electrolyte membrane can form a solid electrolyte layer (300) of an all-solid-state battery (10). The solid electrolyte layer (300) can include the solid electrolyte membrane described above. The solid electrolyte membrane can be manufactured using the manufacturing method of FIG. 9.

[0149] Figure 9 is a flowchart illustrating a method for manufacturing a solid electrolyte membrane according to embodiments of the present invention. Figures 10 to 13 are schematic diagrams illustrating each step of the manufacturing method.

[0150] Referring to FIG. 9, a method for manufacturing a solid electrolyte membrane may include forming a first mixed solution by mixing a first binder (BND1) and a lithium salt (LTS) (S100), forming a second slurry by mixing a sulfide-based solid electrolyte (SE) and a second binder (BND2) (S200), forming a second slurry by adding the first mixed solution to the first slurry (S300), and forming a first membrane by applying the second slurry to a substrate (S400).

[0151]

[0152] Referring to Fig. 10, a first mixed solution can be prepared by mixing a first binder (BND1) and a lithium salt (LTS) (S100).

[0153] The first binder (BND1) may include an acrylic polymer. For example, the first binder (BND1) may include at least one selected from the group consisting of acrylate rubber, acrylonitrile rubber, polyacrylonitrile, polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, and polyacrylic acid. The first binder (BND1) may have a particle shape such as a dot-shaped, spherical, or oblate spherical particle.

[0154] Lithium salt (LTS) can be represented by the following structural formula 1.

[0155] [Structural formula 1]

[0156]

[0157] In the above structural formula 1, R1 and R2 may be the same or different from each other. For example, the size of R1 and the size of R2 may be the same or different from each other. The size may refer to the size of the atoms constituting the substituent, the length of the chain, and / or the volume of the substituent.

[0158] For example, each of R1 and R2 may include a fluorine (F) element. For example, R1 may include the following structural formula 2.

[0159] [Structural formula 2]

[0160]

[0161] In the above structural formula 2, n may be an integer between 1 and 10. For example, R1 may include one selected from the group consisting of -F, -CF3, -CF2CF3, -CF2CF2CF3, -CF2CF2CF2CF3, -CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF2CF3, and -CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3.

[0162] For example, R2 may comprise the following structural formula 3.

[0163] [Structural formula 3]

[0164]

[0165] In the above structural formula 3, the m may be an integer between 1 and 10. For example, R2 may include one selected from the group consisting of -F, -CF3, -CF2CF3, -CF2CF2CF3, -CF2CF2CF2CF3, -CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF3, -CF2CF2CF2CF2CF2CF2CF2CF2CF3, and -CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3. The m may be the same as or different from the n. That is, the lithium salt may have a symmetrical structure or an asymmetrical structure.

[0166] For example, the first lithium salt (LTS1) having a symmetrical structure is LiN(SO2F)2, It may include LiN(SO2CF3)2, LiN(SO2CF2CF3)2, LiN(SO2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, and LiN(SO2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF2CF3)2, etc.

[0167] For example, lithium salts (LTS) having an asymmetric structure may include (FSO2)LiN(SO2CF3), etc.

[0168] The solvent of the mixed solution of the first binder (BND1) and the lithium salt (LTS) may include at least one selected from the group consisting of octyl acetate, nonyl acetate, a hydroxyl solvent, xylene, diethylbenzene, toluene, and isobutyl isobutyrate (IBIB). The hydroxyl solvent may be, for example, a solvent containing a hydroxyl group and an alkyl group. The hydroxyl solvent may be, for example, an alkanol containing 1 to 10 carbon atoms.

[0169] Referring to FIG. 11, a first slurry can be prepared by mixing a solid electrolyte (SE) and a second binder (BND2) (S200).

[0170] Sulfide-based solid electrolytes (SE) are, 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 (SE) may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0171] Alternatively, a sulfide-based solid electrolyte (SE) 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.

[0172] The second binder (BND2) may include a binder used in the solid electrolyte layer (300). For example, the second binder (BND2) may include at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber. However, the second binder (BND2) is not limited to the described examples.

[0173] For example, the second binder (BND2) may be provided as a binder solution. The binder solution may include the second binder (BND2) and a solvent. For example, the binder content may be 2 wt% to 10 wt% relative to the total weight of the binder solution.

[0174] For example, the solvent may be an organic solvent. For example, the solvent may include at least one selected from the group consisting of octylacetate, nonyl acetate, hydroxyl solvents, xylene, diethylbenzene, toluene, and isobutyl isobutyrate (IBIB). The hydroxyl solvent may be, for example, a solvent containing a hydroxyl group and an alkyl group. The hydroxyl solvent may be, for example, an alkanol containing 1 to 10 carbon atoms.

[0175] The second binder (BND2) solution may be transparent or partially transparent. A transparent or partially transparent binder (BND) solution indicates that the sulfide-based solid electrolyte (SE) is mostly or completely dissolved in the organic solvent.

[0176] The content of the sulfide-based solid electrolyte (SE) dissolved in the second binder (BND2) solution may be 30 wt% or less, 20 wt% or less, or 15 wt% or less, based on the total weight of the second binder (BND2) solution. The content of the sulfide-based solid electrolyte (SE) dissolved in the second binder (BND2) solution and included in the second binder (BND2) solution may be 0.1 to 30 wt%, 1 to 20 wt%, or 5 to 15 wt%, based on the total weight of the second binder (BND2) solution. When the second binder (BND32) solution includes the sulfide-based solid electrolyte (SE) in the above-described range, the second binder (BND2) solution may be transparent or translucent.

[0177]

[0178] Referring to FIG. 12, a second slurry can be prepared by adding the first mixed solution to the prepared first slurry (S300). The first mixed solution can be added so that the first binder content is 0.5 to 2 relative to the second binder content in the second slurry.

[0179] Referring to Fig. 13, the prepared second slurry (SES) can be applied to the substrate (SUB) to form a first film (S400).

[0180] For example, the substrate may include at least one selected from the group consisting of a porous polymer matrix, a release film, a foil, aluminum, and SUS.

[0181] Application can be carried out in a conventional manner. For example, application can be carried out using a bar coater, blade coater, etc. Application can be carried out by any method capable of applying slurry, and is not limited to the examples described.

[0182] For example, the step may include forming a porous polymer matrix (PW) on a release film (RF) (a1); laminating a binder (BD) on the porous polymer matrix (PW) (a2); and applying a solid electrolyte slurry (SES) on the porous polymer matrix (PW) (a3).

[0183] A porous polymer matrix (PW) can be formed on a release film (RF) (a1). 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 be perpendicular to the first direction (D1). The porous polymer matrix (PW) can be formed on the release film (RF). That is, the porous polymer matrix (PW) can be laminated along a third direction (D3). The third direction (D3) can be perpendicular to the first direction (D1) and the second direction (D2).

[0184] The porous polymer matrix (PW) may include a plurality of pores. For example, the porous polymer matrix (PW) may have a porosity of 60% or more, for example, a porosity of 60% to 100%, or a porosity of 70% to 80%. For example, the pore size of the porous polymer matrix (PW) may be 50 nm to 500 μm. When the porosity and pore size satisfy the numerical ranges described above, the solid electrolyte slurry can penetrate into the porous polymer matrix, and the porous polymer matrix can retain a sufficient amount of solid electrolyte therein to function as an electrolyte membrane.

[0185] The porous polymer matrix (PW) may have a thin thickness. The porous polymer matrix (PW) may have a thickness of 5 μm to 20 μm. For example, the porous polymer matrix (PW) may have a thickness of 10 μm to 15 μm.

[0186] The weight of the porous polymer matrix (PW) is 2 g / m 2 4g / m 2 may be. For example, the weight of the porous polymer matrix (PW) is 2.5 g / m 2 3.5g / m 2 It could be.

[0187] The tensile strength of the porous polymer matrix (PW) may be 0.1 N / mm to 0.2 N / mm. For example, the tensile strength of the porous polymer matrix (PW) may be 0.1 N / mm to 0.13 N / mm.

[0188] The air permeability per thickness of the porous polymer matrix (PW) may be from 0.1 sec / 100 ml to 1 sec / 100 ml. For example, the air permeability per thickness of the porous polymer matrix (PW) may be from 0.1 sec / 100 ml to 0.5 sec / 100 ml.

[0189] The porous polymer matrix (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.

[0190] In one embodiment, the porous polymer matrix (PW) may be a porous nonwoven fabric.

[0191] A binder (BD) can be laminated onto a porous polymer matrix (PW) (a2). According to one embodiment of the present invention, the porous polymer matrix (PW) can include a first region (R1) and a second region (R2). The first region (R1) can be located on both sides of the porous polymer matrix. The second region (R2) can be a region remaining excluding the first region (R1). The binder (BD) can be laminated onto the first region (R1) of the porous polymer matrix (PW).

[0192] Laminating with a binder (BD) (a2) may include coating with a binder (BD) (a2-1), and curing the binder (BD) (a2-2).

[0193] The binder (BD) can be coated on the first region (R1) of the porous polymer matrix (PW) (a2-1). That is, the binder (BD) can be dropped onto the first region (R1) of the porous polymer matrix (PW). The coating method is not limited as long as it is a method used for conventional coating.

[0194] The binder (BD) may include at least one of a thermosetting resin or an ultraviolet curable resin.

[0195] A thermosetting resin can be defined as a resin that can be cured through drying. For example, the thermosetting resin may include at least one selected from the group consisting of cellulose, fluorine-based resins, acrylate-based resins, and polyolefin-based resins. For example,

[0196] The cellulose may include a cellulose derivative. For example, the cellulose may include cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylcellulose, carboxyl methyl cellulose, and the like.

[0197] For example, the fluororesin may include polyvinylidene fluoride, polytetrafluoroethylene, polychlorotrifluoroethylene, modified copolymers, etc. The modified copolymer may include polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, etc.

[0198] For example, the acrylate resin may include polymethyl methacrylate, polybutylacrylate, polyacrylonitrile, or a copolymer thereof. The copolymer may include a copolymer of polyvinylpyrrolidone, polyvinylacetate, polyethylene oxide, polyacrylate, and polypropylene.

[0199] A UV-curable resin can be defined as a resin that can be cured by ultraviolet rays. For example, the UV-curable resin may include at least one selected from the group consisting of unsaturated polyester resin, polyester acrylate resin, polyurethane, and epoxy acrylate resin.

[0200] Curing with a binder (BD) (a2-2) may include at least one of thermal curing and ultraviolet curing. For example, thermal curing may be performed at a temperature of 80°C to 110°C for 1 to 10 minutes. For example, ultraviolet curing may be performed with ultraviolet (UV) light having a wavelength of 200 nm to 365 nm.

[0201] Laminating with a binder (BD) (a2) may further include electrostatically removing the porous polymer matrix (PW) (a2-3). Electrostatically removing the porous polymer matrix (PW) (a2-3) may be a process for removing static electricity from the porous polymer matrix (PW). For example, electrostatically removing the porous polymer matrix (PW) (a2-3) may include electrostatically removing the porous polymer matrix (PW) using distilled water or the like.

[0202] The solid electrolyte slurry (SES) can be applied onto the second region (R2) of the porous polymer matrix (PW) (a3). That is, the solid electrolyte slurry (SES) can be coated and / or dripped onto the second region (R2) of the porous polymer matrix (PW). The application method is as described above.

[0203] The sulfide-based solid electrolyte in the solid electrolyte slurry (SES) can penetrate into the pores of the porous polymer matrix. For example, the average particle diameter (D50) of the sulfide-based solid electrolyte may be 500 nm to 7 μm, or 1 μm to 3 μm.

[0204] Coating with a solid electrolyte slurry (SES) (a3) ​​may include permeation of the solid electrolyte slurry (SES) into the porous polymer matrix (PW). That is, when coating the solid electrolyte slurry (SES) onto the second region (R2), the solid electrolyte slurry (SES) may permeate into the pores of the porous polymer matrix (PW). When the solid electrolyte slurry (SES) permeates, at least a portion of the second region (R2) of the porous polymer matrix (PW) may be separated from the release film (RF). The solid electrolyte slurry (SES) may move through the pores of the porous polymer matrix (PW) to fill the separated gaps.

[0205]

[0206] An additional drying process may be performed on the first film produced.

[0207] In one embodiment, a second film can be formed by performing a first drying process at a first temperature on a first film.

[0208] The first temperature may be between 80°C and 150°C. Alternatively, the first temperature may be between 80°C and 130°C. When the first temperature satisfies the above-described range, the solvent within the first film may be removed through the first drying process.

[0209] The first drying process can be performed for 1 minute to 5 hours. For example, the first drying time can be 5 minutes to 1 hour. If the first drying time satisfies the above range, the solvent within the first film can be removed through the first drying process.

[0210] The first drying process may be performed in a dryer. For example, the dryer may include a convection oven, etc. That is, the first drying process may be performed in a convection oven.

[0211]

[0212] A second drying process at a second temperature may be additionally performed on the second film manufactured above. A third film may be formed through the second drying process. The second drying process may include melting a lithium salt. For example, the second drying process may remove the solvent remaining within the second film after completing the first drying process.

[0213] The second temperature may be between 50°C and 90°C. Alternatively, the second temperature may be between 70°C and 90°C. The second drying process may be performed for between 30 minutes and 10 hours. For example, the second drying time may be between 60 minutes and 6 hours. When the temperature and time of the second drying process satisfy the above ranges, the solvent within the second film may be effectively removed.

[0214] The second drying process may include vacuum drying. The second drying process may be performed in a second dryer. For example, the second dryer may include a vacuum oven or the like. That is, the second drying process may be performed in a vacuum oven or the like.

[0215]

[0216] A method for manufacturing a solid electrolyte membrane according to one embodiment of the present invention may further include performing a third drying process at a third temperature on a third membrane.

[0217] The third temperature may be lower than the second temperature. The third temperature may be room temperature. For example, the third temperature may be between 20°C and 40°C. This allows the lithium salt and binder to be cured.

[0218]

[0219] A solid electrolyte membrane manufactured by the above-described manufacturing method may have the following characteristics.

[0220] Solid electrolyte membranes can exhibit excellent flexibility and mechanical strength. This allows for the application of both warm isostatic pressing (WIP) and roll pressing during the manufacturing of all-solid-state batteries, thereby improving the processability and productivity of all-solid-state batteries. Furthermore, short-circuiting can be prevented during rapid charging of all-solid-state batteries.

[0221] Solid electrolyte membranes can exhibit excellent ionic conductivity. For example, the ionic conductivity of the solid electrolyte membrane at 25°C can be 0.25 mS / cm to 1 mS / cm. This can improve the electrochemical properties of all-solid-state batteries.

[0222]

[0223] 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.

[0224]

[0225]

[0226] Example

[0227] (1) Manufacturing of solid electrolyte membrane

[0228] A solid electrolyte membrane was prepared including a sulfide-based solid electrolyte (Li6PS5Cl; LPSCl), a first binder (acrylate rubber), a second binder (polyvinylidene fluoride / hexafluoropropylene copolymer; PVdF-HFP), and a lithium salt (LiN(SO2CF3)2).

[0229] A mixed solution was prepared by adding the first binder (BND1) and lithium salt (LTS) to a solvent (oxyl acetate) at a weight ratio of 5:2 (S100).

[0230] A second binder (PVdF-HFP) and a solvent (oxyl acetate) were mixed to prepare an 8 wt% binder solution. A sulfide-based solid electrolyte (LPSCL, D50=3) was added to the binder solution and mixed using a thinky mixer to prepare a first slurry (S200).

[0231] A mixed solution of the first binder and lithium salt was added to the first slurry, a dispersant was additionally added, and the mixture was mixed using a sinky mixer to prepare a second slurry (S300).

[0232] The weight ratio of the sulfide-based solid electrolyte, the first binder, the second binder, the lithium salt, and the dispersant was 94.78:2:2:0.6:0.62. The total binder amount of the prepared slurry was 4 wt%. The prepared slurry was applied onto a non-woven fabric using a bar coater to form a first film (S400). The first film was dried in a convection oven at a first temperature (110°C) for 5 minutes (first drying process) to form a second film (S500). The second film was dried in a vacuum oven at a second temperature (80°C) for 4 hours (second drying process) to form a third film. The third film was left at room temperature (third drying process) to prepare a solid electrolyte film.

[0233] (2) All-solid-state battery manufacturing

[0234] LiNi0.8Co0 as the positive electrode active material described above. 15 Mn0. 05O2 (NCM) powder was prepared. A crystalline argyrodite-based solid electrolyte (Li6PS5Cl) was prepared as a solid electrolyte. A polytetrafluoroethylene (PTFE) binder (Teflon binder from DuPont) was prepared as a binder. Carbon nanofibers (CNF) were prepared as a conductive material. These materials were mixed in a weight ratio of positive active material: solid electrolyte: conductive material: binder = 84.2:11.5:2.9:1.4, and the mixture was formed into a large sheet shape to manufacture a positive electrode sheet. The manufactured positive electrode sheet was pressed onto a positive electrode current collector made of 18 μm thick carbon-coated aluminum foil to manufacture a positive electrode layer. The thickness of the positive electrode active material layer included in the positive electrode layer was approximately 100 μm. Lithium metal with a thickness of approximately 30 μm was used as the negative electrode layer.

[0235] A solid electrolyte membrane was placed on the positive electrode layer. A negative electrode layer was laminated on the solid electrolyte. The prepared laminate was plate pressed at 100 MPa for 10 minutes at 25°C to manufacture an all-solid-state battery.

[0236]

[0237] Example 2

[0238] A solid electrolyte membrane was manufactured in the same manner as in Example 1, except that the weight ratio of the sulfide-based solid electrolyte, the first binder, the second binder, the lithium salt, and the dispersant was mixed to be 93.65:2.5:2.5:0.75:0.6. The total binder amount of the manufactured solid electrolyte membrane was 5 wt%.

[0239]

[0240] Example 3

[0241] A solid electrolyte membrane was manufactured in the same manner as in Example 1, except that the weight ratio of the sulfide-based solid electrolyte, the first binder, the second binder, the lithium salt, and the dispersant was mixed to be 90.7:3.5:4:1.2:0.6. The total binder amount of the manufactured solid electrolyte membrane was 7.5 wt%.

[0242]

[0243] Comparative Example 1

[0244] A solid electrolyte membrane containing a sulfide-based solid electrolyte (Li6PS5Cl; LPSCl) and one type of binder (acrylate rubber) was prepared.

[0245] An 8 wt% binder solution was prepared by mixing a binder (PVdF-HFP) and a solvent (octyl acetate). A sulfide-based solid electrolyte (LPSCl, D50=3) was added to the binder solution and mixed with a thin mixer to prepare a slurry. The weight ratio of the sulfide-based solid electrolyte and the binder was 98:2. The prepared slurry was applied onto a nonwoven fabric using a bar coater to form a first film. The first film was dried in a convection oven at a first temperature (80°C) for 5 minutes (first drying process) to form a second film (S500). The second film was dried in a vacuum oven at a second temperature (110°C) for 4 hours (second drying process) to form a third film. The third film was left at room temperature (third drying process) to produce a solid electrolyte membrane.

[0246] An all-solid-state battery was manufactured by manufacturing a positive electrode layer and a negative electrode layer using the same method as in Example 1.

[0247]

[0248] Comparative Example 2

[0249] A solid electrolyte membrane was prepared in the same manner as in Comparative Example 1, except that hydroxylated nitrile butadiene rubber (H-NBR) was used instead of acrylate rubber as a binder.

[0250]

[0251] Comparative Example 3

[0252] A solid electrolyte membrane was prepared in the same manner as in Comparative Example 1, except that PVdF-HFP was used instead of acrylate rubber as a binder.

[0253]

[0254] Comparative Example 4

[0255] A solid electrolyte membrane was prepared comprising a sulfide-based solid electrolyte (Li6PS5Cl; LPSCl), a first binder (acrylate rubber), and a second binder (polyvinylidene fluoride / hexafluoropropylene copolymer; PVdF-HFP).

[0256] A solid electrolyte membrane and an all-solid-state battery were prepared in the same manner as in Comparative Example 1, except that acrylate rubber and PVdF-HFP were mixed in a weight ratio of 1:1 as a binder.

[0257]

[0258] Evaluation Example 1: Flexibility Evaluation

[0259] The flexibility of the solid electrolyte membranes according to Examples 1 to 4 and Comparative Examples 1 to 4 was evaluated. A rod was fabricated for each pie, and the solid electrolyte membranes according to the Examples and Comparative Examples were cut into pieces measuring 5 cm in width and 5 cm in length. The cut electrodes were bent in half and brought into contact with the rods. The electrodes were observed for cracks in each pie, and the evaluation results are shown in Table 1 below.

[0260] Binder and lithium salt 10 Φ (mm) Crack occurrence 5 Φ (mm) Crack occurrence Example 1 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 2XX Example 2 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 2XX Example 3 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 2XX Comparative Example 1 Acrylate rubber XX Comparative Example 2 H-NBROO Comparative Example 3 PVdF-HFPOO Comparative Example 4 Acrylate rubber + PVdF-HFPXO

[0261] Referring to Table 1, it can be seen that the solid electrolyte membranes according to the examples did not crack up to 5 pi, whereas the solid electrolyte membranes according to the comparative examples cracked when a 5 pi rod was used. In other words, it can be seen that the solid electrolyte membranes according to the examples have superior flexibility.

[0262] Evaluation Example 2: Ionic Conductivity Evaluation

[0263] The ionic conductivity of the solid electrolyte membranes according to the examples and comparative examples was measured. The impedance of the solid electrolyte membranes was measured using a potentiostat (AUTOLAB PGSTAT30 (Metrohm Autolab Co. Ltd.), and the ionic conductivity at 25°C was measured from the Nyquist plot. The results are shown in Table 2.

[0264] Binder and lithium salt ion conductivity (mS / cm) Example 1 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 20.57 Example 2 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 20.48 Example 3 Acrylate rubber + PVdF-HFP + LiN(SO2CF3) 20.32 Comparative Example 1 Acrylate rubber 0.47 Comparative Example 2 H-NBR 0.22 Comparative Example 3 PVdF-HFP 0.45 Comparative Example 4 Acrylate rubber + PVdF-HFP 0.56

[0265] Referring to Table 2, it can be confirmed that the solid electrolyte membrane of Example 1 has superior ionic conductivity to the solid electrolyte membranes of Comparative Examples 1 to 4 using the same amount of binder. It can also be confirmed that the solid electrolyte membranes of Examples 2 and 3 with increased binder content have ionic conductivity similar to that of the solid electrolyte membranes according to the Comparative Examples.

[0266] Evaluation Example 3: Rapid Charging Evaluation

[0267] Rapid charging evaluation was performed on the all-solid-state batteries according to Example 1 and Comparative Example 1.

[0268] After charging to an upper limit voltage of 4.25 V with a constant current of 1 C, discharge was performed to an end-of-discharge voltage of 2.5 V with a constant current of 0.1 C. Charging and discharging were performed while increasing the charging speed (C rate), and the occurrence of short circuits at each C rate is shown in Table 3 below.

[0269] 1C charge / 0.1C discharge2C charge / 0.2C discharge3C charge / 0.3C discharge4C charge / 0.4C discharge5C charge / 0.5C dischargeExample 1XXXXXComparative example 1XXOOO

[0270] Referring to Table 3, it can be seen that the all-solid-state battery according to Example 1 can be charged without a short circuit up to 5C, whereas the all-solid-state battery according to Comparative Example 1 has a short circuit when charged at 3C.

[0271] Evaluation Example 4: Initial Electrochemical Characteristics Evaluation

[0272] The charge / discharge efficiency and initial capacity retention rate of the all-solid-state batteries were evaluated using the all-solid-state batteries manufactured according to Example 1, Comparative Example 1, and Comparative Example 4.

[0273] The all-solid-state battery was charged to an upper limit voltage of 4.25 V at a constant current of 0.1 C at 45°C, and then discharged to an end-of-discharge voltage of 2.5 V at a constant current of 0.1 C (1 st The initial charge / discharge efficiency is shown in Table 4 below.

[0274] The all-solid-state battery was charged to an upper limit voltage of 4.25 V at a constant current of 0.33 C at 45°C, and then discharged to an end-of-discharge voltage of 2.5 V at a constant current of 0.33 C (2 nd The charge / discharge efficiency is shown in Table 5 below.

[0275] The all-solid-state battery was charged to an upper limit voltage of 4.25 V at a constant current of 1 C at 45°C, and then discharged to an end-of-discharge voltage of 2.5 V at a constant current of 1 C (3 rdThe charge / discharge efficiency is shown in Table 6 below.

[0276] The capacity retention rate after each cycle is shown in Table 7.

[0277] The charge / discharge efficiency and capacity retention rate were calculated according to Equations 1 and 2, respectively.

[0278] [Formula 1]

[0279] Charge / discharge efficiency (%) = (initial discharge capacity / initial charge capacity)*100

[0280]

[0281] [Formula 2]

[0282] Capacity retention rate (%) = (n th Discharge amount in cycle / 1 st Discharge amount in cycle)*100

[0283]

[0284] Charge capacity (mAh / g)Discharge capacity (mAh / g)Charge / discharge efficiency (%)Example 1249.2206.282.8Comparative example 1248.3208.684.0Comparative example 4250.1203.981.5

[0285] Charge capacity (mAh / g)Discharge capacity (mAh / g)Charge / discharge efficiency (%)Example 1206.0193.593.9Comparative example 1208.0194.693.6Comparative example 4203.1189.893.4

[0286] Charge capacity (mAh / g)Discharge capacity (mAh / g)Charge / discharge efficiency (%)Example 1193.1181.193.8Comparative example 1194.0180.092.8Comparative example 4188.8175.392.8

[0287] 1 st Cycle capacity maintenance rate (%)2 nd Cycle capacity maintenance rate (%)3 rd Cycle capacity maintenance rate (%) Example 110093.887.8 Comparative example 110093.386.3 Comparative example 410093.185.9

[0288] Referring to Tables 4 to 7, it can be confirmed that the all-solid-state battery according to Example 1 has superior charge / discharge efficiency and capacity retention rate compared to the all-solid-state battery according to Comparative Example 4. In addition, it can be confirmed that the all-solid-state battery according to Example 1 has a charge / discharge efficiency in the first cycle that is about 1.2% lower than the all-solid-state battery according to Comparative Example 1, but the charge / discharge efficiency and capacity retention rate thereafter are superior.

[0289] Evaluation Example 5: Whether cracks occur after roll pressing

[0290] A solid electrolyte membrane manufactured according to Example 1 was laminated on a cathode layer manufactured according to Example 1, and then roll pressing was performed, and the results are shown in Fig. 14. Roll pressing was performed at 100°C, under the pressure shown in Fig. 14, and at a speed of 0.5 m / min. Referring to Fig. 14, it can be confirmed that the solid electrolyte membrane manufactured according to Example 1 did not exhibit cracks even after roll pressing at a pressure of 3.0 ton / cm.

[0291]

[0292] 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 concept or essential features thereof. Therefore, the embodiments described above should be understood to be illustrative in all respects and not restrictive.

Claims

1. A sulfide-based solid electrolyte comprising a first binder, a second binder, and a lithium salt, The above second binder is different from the above first binder, The above first binder forms a complex with the lithium salt, The above sulfide-based solid electrolyte comprises first particles and second particles, The second binder bonds to the surfaces of each of the first particle and the second particle, A solid electrolyte membrane in which the first binder is bonded to the second binder on the first particle and the second binder on the second particle.

2. In paragraph 1, A solid electrolyte membrane in which the weight ratio of the lithium salt to the first binder is 0.1 to 0.

5.

3. In paragraph 1, A solid electrolyte membrane in which the weight ratio of the first binder and the second binder is 0.5:1 to 1:0.

5.

4. In paragraph 1, A solid electrolyte membrane in which the total amount of binder including the first binder and the second binder is 3 wt% to 8 wt%.

5. In paragraph 1, A solid electrolyte membrane in which the first binder forms a point bond with the second binder through hydrogen bonding.

6. In paragraph 1, A solid electrolyte membrane in which the second binder forms a line bond to the surface of each of the first particle and the second particle.

7. In paragraph 1, The above first binder is a solid electrolyte membrane comprising an acrylic polymer.

8. In paragraph 1, A solid electrolyte membrane comprising the second binder at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

9. In paragraph 1, The above lithium salt is a solid electrolyte membrane comprising at least one selected from the group consisting of compounds represented by the following structural formula 1, LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, Li(FSO2)2N, Li(CF3SO2)3C, LiSbF6, LiPF3(CF2CF3)3, LiPF3(C2F5)3, LiPF3(CF3)3, and LiB(C2O4)2: [Structural formula 1] In the above structural formula 1, R1 and R2 are the same or different from each other, Each of the above R1 and R2 contains a fluorine (F) element.

10. In paragraph 1, The above sulfide-based solid electrolyte is 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 A solid electrolyte membrane comprising at least one selected from the group consisting of (0≤x≤2).

11. A sulfide-based solid electrolyte comprising a first binder, a second binder, and a lithium salt, The above first binder forms a complex with the lithium salt, The above first binder comprises an acrylic polymer, A solid electrolyte membrane, wherein the second binder comprises at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

12. In paragraph 11, A solid electrolyte membrane in which the weight ratio of the lithium salt to the first binder is 0.1 to 0.

5.

13. In paragraph 11, A solid electrolyte membrane in which the total amount of binder including the first binder and the second binder is 3 wt% to 8 wt%.

14. In paragraph 11, The above sulfide-based solid electrolyte comprises first particles and second particles, The second binder bonds to the surfaces of each of the first particle and the second particle, A solid electrolyte membrane in which the first binder is bonded to the second binder on the first particle and the second binder on the second particle.

15. In paragraph 11, A solid electrolyte membrane in which the first binder forms a point bond with the second binder through hydrogen bonding.

16. Forming a first mixed solution by mixing a first binder and a lithium salt; Forming a first slurry by mixing a sulfide-based solid electrolyte and a second binder; Forming a second slurry by adding the first mixed solution to the first slurry; and Including forming a first film by applying the second slurry to a substrate, The above first binder comprises an acrylic polymer, A method for producing a solid electrolyte membrane, wherein the second binder comprises at least one selected from the group consisting of styrene butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polyethylene glycol, nitrile butadiene rubber, and hydrogenated nitrile butadiene rubber.

17. In paragraph 16, Forming a second film by performing a first drying process at a first temperature on the first film; and forming a third film by performing a second drying process at a second temperature on the second film; A method for manufacturing a solid electrolyte membrane wherein the second temperature is higher than the first temperature.

18. In paragraph 16, A method for producing a solid electrolyte membrane in which the first binder forms a complex with the lithium salt.

19. In paragraph 16, A method for producing a solid electrolyte membrane, wherein the weight ratio of the lithium salt to the first binder is 0.1 to 0.

5.

20. In paragraph 16, A method for manufacturing a solid electrolyte membrane, wherein the total amount of binder including the first binder and the second binder is 3 wt% to 8 wt%.

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