Adhesive composition, all-solid-state battery, and method for manufacturing all-solid-state battery

Abstract

The present invention relates to an adhesive composition, an all-solid-state battery, and a method for manufacturing an all-solid-state battery. More specifically, a cyclic polymer is included, the cyclic polymer comprising first and second repeating units bonded to each other by a disulfide bond.

Description

Adhesive composition, all-solid-state battery and method for manufacturing an all-solid-state battery

[0001] The present invention relates to an adhesive composition, an all-solid-state battery, and a method for manufacturing an all-solid-state battery.

[0002] Recently, driven by industrial demands, the development of batteries with high energy density and safety is actively underway. For example, lithium-ion batteries are being commercialized not only in the fields of information and communication devices but also in the automotive sector. In the automotive sector, safety is considered particularly important because it is directly related to human life.

[0003] Recently, all-solid-state batteries in which liquid electrolytes are replaced with solid electrolytes have been proposed. By not using flammable organic dispersion media, all-solid-state batteries can significantly reduce the likelihood of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries can offer significantly higher safety compared to lithium-ion batteries that use liquid electrolytes.

[0004] The problem that the present invention aims to solve is to provide an adhesive composition capable of bonding the interfaces of different solid electrolyte layers and reducing voids within the interfaces.

[0005] Another problem that the present invention aims to solve is to provide an all-solid-state battery with improved performance (resistance, etc.) and a method for manufacturing the same.

[0006] An adhesive composition according to one embodiment of the present invention comprises a cyclic polymer, wherein the cyclic polymer comprises a first repeating unit represented by the following structural formula 1 and a second repeating unit represented by the following structural formula 2, and the first repeating unit and the second repeating unit may be bonded to each other by a disulfide bond:

[0007] [Structural Formula 1]

[0008]

[0009] The above L1, the above L2 and the above L3 are each independently a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group, and the above Y1 and the above Y2 are each independently oxygen or sulfur, and

[0010] [Structural Formula 2]

[0011]

[0012] The above L4 may be a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkylene group.

[0013] A solid-state battery according to one embodiment of the present invention comprises a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, wherein the solid electrolyte layer comprises: a first solid electrolyte layer comprising a first electrolyte particle; a second solid electrolyte layer comprising a second electrolyte particle; and an adhesive layer interposed between the first and second solid electrolyte layers to bond them together, wherein the adhesive layer comprises: a cyclic polymer, wherein the cyclic polymer comprises a first repeating unit represented by the following structural formula 1 and a second repeating unit represented by the following structural formula 2, and wherein the first repeating unit and the second repeating unit may be bonded to each other by a disulfide bond:

[0014] [Structural Formula 1]

[0015]

[0016] The above L1, the above L2 and the above L3 are each independently a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group, and the above Y1 and the above Y2 are each independently oxygen or sulfur, and

[0017] [Structural Formula 2]

[0018]

[0019] The above L4 may be a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkylene group.

[0020] A method for manufacturing an all-solid-state battery according to one embodiment of the present invention comprises: forming a negative electrode laminate by stacking and pressing a negative electrode layer and a first solid electrolyte layer; forming an anode laminate by stacking and pressing a positive electrode layer and a second solid electrolyte layer; coating an adhesive composition on the surface of at least one of the first solid electrolyte layer and the second solid electrolyte layer; and forming a composite by stacking and pressing the negative electrode laminate and the positive electrode laminate, wherein the adhesive composition may be the adhesive composition described in claim 1.

[0021] An adhesive composition according to one embodiment of the present invention can bond the interfaces of different solid electrolyte layers and reduce voids within the interfaces.

[0022] The all-solid-state battery according to one embodiment of the present invention can have its performance (resistance, etc.) improved.

[0023] A method for manufacturing an all-solid-state battery according to one embodiment of the present invention can provide an all-solid-state battery with improved performance (resistance, etc.).

[0024] FIG. 1 is a cross-sectional view of an all-solid-state battery according to embodiments of the present invention.

[0025] FIG. 2 is a cross-sectional view of a solid electrolyte layer according to embodiments of the present invention.

[0026] FIG. 3 is an enlarged view of a solid electrolyte layer according to one embodiment of the present invention.

[0027] FIG. 4 is a flowchart illustrating a method for manufacturing an all-solid-state battery according to embodiments of the present invention.

[0028] FIG. 5 is a schematic diagram illustrating step S100 of a method for manufacturing an all-solid-state battery according to embodiments of the present invention.

[0029] FIG. 6 is a schematic diagram illustrating step S300 of a method for manufacturing an all-solid-state battery according to embodiments of the present invention.

[0030] FIGS. 7, FIGS. 8 and FIGS. 9 are schematic diagrams illustrating step S600 of a method for manufacturing an all-solid-state battery according to embodiments of the present invention.

[0031] FIGS. 10 and FIGS. 11 are schematic diagrams illustrating step S900 of a method for manufacturing an all-solid-state battery according to embodiments of the present invention.

[0032] In order to fully understand the structure and effects of the present invention, preferred embodiments of the present invention are described with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and various modifications can be made. The description of these embodiments is provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention.

[0033] In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the components are exaggerated for the effective description of the technical content. Throughout the specification, parts indicated by the same reference numeral represent the same components.

[0034] The embodiments described herein will be described with reference to cross-sectional and / or plan views, which are exemplary illustrations of the invention. In the drawings, the thicknesses of films and regions are exaggerated for effective description of the technical content. Accordingly, the regions illustrated in the drawings are schematic in nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific forms of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this specification, these components should not be limited by such terms. These terms are used merely to distinguish one component from another. The embodiments described and illustrated herein also include their complementary embodiments.

[0035] The terms used herein are for describing the embodiments and are not intended to limit the invention. In this specification, the singular form includes the plural form unless specifically stated otherwise in the text. As used herein, 'comprises' and / or 'comprising' do not exclude the presence or addition of one or more other components to the mentioned components.

[0036]

[0037] FIG. 1 is a cross-sectional view of an all-solid-state battery (10) according to one embodiment of the present invention.

[0038] 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 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).

[0039] An anode layer (100) of one embodiment includes an anode current collector (110) and an anode active material layer (120) disposed on the anode current collector (110). The anode active material layer (120) may include an anode active material, a solid electrolyte, a conductive material, and a binder.

[0040] The positive current collector (110) can provide a reference surface on which the positive active material layer (120) is placed. The positive current collector (110) may include, for example, a plate or foil comprising indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0041] Meanwhile, unlike as illustrated in FIG. 1, the positive current collector (110) may be omitted in one embodiment of the present invention. Although not illustrated, a carbon layer with a thickness of 0.1 μm to 4 μm may be further disposed between the positive current collector (110) and the positive active material layer (120) to increase the bonding strength between the positive current collector (110) and the positive active material layer (120).

[0042] The cathode active material is a material capable of reversibly absorbing and desorbing lithium ions. The cathode active material may include, for example, 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, as well as nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide, but is not necessarily limited to these. Each cathode active material may be a single material or a mixture of two or more materials.

[0043] Lithium transition metal oxides are, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b B b O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mn b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mn b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b E c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mn d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiG bO2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f It is a compound represented by any one of Fe2(PO4)3 (0≤f≤2) or LiFePO4. In such compounds, the uppercase “A” is Ni, Co, Mn, or a combination thereof; the uppercase “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; the uppercase “D” is O, F, S, P, or a combination thereof; the uppercase “E” is Co, Mn, or a combination thereof; the uppercase “F” is F, S, P, or a combination thereof; the uppercase “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; the uppercase “Q” is Ti, Mo, Mn, or a combination thereof; the uppercase “I” is Cr, V, Fe, Sc, Y, or a combination thereof; and the uppercase “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0044] 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 and metal atomic layers are alternately and regularly arranged in a specific direction, thereby forming a two-dimensional plane for each atomic layer. The "cubic rock salt type structure" represents a sodium chloride (NaCl) type structure, which is a type of crystal structure; specifically, it exhibits a structure in which face-centered cubic lattices (fcc) formed by cations and anions, respectively, are offset from each other by half the ridge of the unit lattice. Lithium transition metal oxides having such a layered rock salt type structure are, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지(10)의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0045] The aforementioned compound contained in the cathode active material may be covered by a coating layer (not shown). The cathode active material may also be a mixture of the aforementioned compound and the compound to which the coating layer is added. Meanwhile, the coating layer added to the surface of the cathode active material may include, for example, oxides, hydroxides, oxyhydroxides, oxycarbonates, or hydroxycarbonates of the following coating elements. The compounds forming this coating layer are 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 for forming the coating layer is selected within a range that does not adversely affect the physical properties of the cathode active material. The method for forming the coating layer is, for example, spray coating or immersion.

[0046] When the positive electrode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), the capacity density of the all-solid-state battery (10) is increased, and the metal leaching of the positive electrode active material in the charged state can be reduced. As a result, the cycle characteristics of the all-solid-state battery (10) in the charged state are improved. Meanwhile, “cycle characteristics” is a characteristic that indicates the degree of deterioration of the all-solid-state battery (10) due to charging and discharging of the all-solid-state battery (10). An all-solid-state battery (10) with high cycle characteristics has a small degree of deterioration due to charging and discharging, while an all-solid-state battery (10) with low cycle characteristics may have a large degree of deterioration due to charging and discharging.

[0047] The shape of the cathode active material may include particle shapes such as spheres or ellipsoids. The particle size and content of the cathode active material are not particularly limited.

[0048] The solid electrolyte may include a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, and Li2S-P2S5-Z m S n (m, n are positive numbers, uppercase “Z” is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, uppercase “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).

[0049] Sulfide-based solid electrolytes 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 x It may be an argyrodite-type compound comprising one or more selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound comprising one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0050] Alternatively, sulfide-based solid electrolytes are Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, 0≤c≤2). Here, X may be F, Br, Cl, or a combination thereof. M can be scandium (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. there is.

[0051] The density of the azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or higher for the azyrodite-type solid electrolyte, the internal resistance of the all-solid-state battery is reduced, and defects such as penetration and short circuit of the solid electrolyte film due to lithium dendrite formation 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 smaller average particle size (D50) compared to the solid electrolyte included in the solid electrolyte layer (300). For example, the average 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 average particle size (D50) of the solid electrolyte included in the solid electrolyte layer (300). Meanwhile, the average particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0053] The positive electrode active material layer (120) may include a conductive material. The conductive material may have conductivity without causing chemical changes in the all-solid-state battery (10), thereby increasing the conductivity of the positive electrode active material and the solid electrolyte. The conductive material may include a carbon-based material. The conductive material may include, for example, one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0054] The positive active material layer (120) may further include a binder. The binder may include a material for bonding the positive active material, solid electrolyte, and conductive material included in the positive active material layer (120), and for improving the bonding strength with the positive current collector (110). The binder may include, for example, polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0055] Based on 100 parts by weight of the total positive active material, solid electrolyte, conductive material, and binder, the positive active material layer (120) may contain 85 parts by weight or more and 92 parts by weight or less of the positive active material. Based on 100 parts by weight of the total positive active material, solid electrolyte, conductive material, and binder, the positive active material layer (120) may contain 0.5 parts by weight or more and 1.5 parts by weight or less of the binder.

[0056] Based on 100 parts by weight of solid electrolyte, the positive active material layer (120) may contain 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 active material layer (120) in an amount less than 1 part by weight based on 100 parts by weight of solid electrolyte, the proportion of the conductive material decreases, and the electrical conductivity of the positive active material layer (120) may decrease. If the conductive material is included in the positive active material layer (120) in an amount exceeding 50 parts by weight based on 100 parts by weight of solid electrolyte, the proportion of the conductive material is excessively high, and a coating layer covering the surface of the solid electrolyte may not be properly formed.

[0057] The positive active material layer (120) may further include additives such as fillers, coating agents, dispersants, and ion conductivity aids in addition to the positive active material, solid electrolyte, conductive material, and binder described above.

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

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

[0060] Sulfide-based solid electrolytes 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 x It may be an argyrodite-type compound comprising one or more selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound comprising one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0061] Alternatively, sulfide-based solid electrolytes are Li 7-a M a PS 6-c X cIt may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)). Here, X may be F, Br, Cl, or a combination thereof. M can be scandium (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. there is.

[0062] The density of the azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or higher for the azyrodite-type solid electrolyte, the internal resistance of the all-solid-state battery is reduced, and defects such as penetration and short circuits of the solid electrolyte film due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

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

[0064] The negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode coating layer (220) on the negative electrode current collector (210). The negative electrode current collector (210) may provide a reference surface on which the negative electrode coating layer (220) is placed. The negative electrode current collector (210) may include, for example, a material that does not react with lithium, that is, does not form any alloys or compounds with lithium. For example, the negative electrode current collector (210) may include at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector (210) may be about 10 μm. The thickness of the negative electrode current collector (210) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0065] The negative current collector (210) may be composed of one of the metals described above, or may include an alloy of two or more metals or a coating material. The negative current collector (210) may, for example, have a plate-like or foil-like shape. Meanwhile, in one embodiment, the negative current collector (210) may be omitted.

[0066] The negative electrode layer (200) may further include a second electrode tab extending from one side of the negative electrode current collector (210). The second electrode tab may be welded to an electrode lead and connected to an external terminal. The electrode lead welded to the second electrode tab may be different from the electrode lead welded to the first electrode tab.

[0067] The negative electrode coating layer (220) can cause lithium metal to grow between the all-solid-state battery (10) and the negative electrode current collector (210) during charging. Alternatively, the negative electrode coating layer (220) can cause lithium metal to grow or form an alloy with lithium inside the all-solid-state battery (10) during charging. The negative electrode coating layer (220) can serve as a protective layer for lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0068] The cathode coating layer (220) may include metal and carbon. For example, the cathode coating layer (220) may include at least one metal 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 cathode coating layer (220) may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the cathode coating layer (220) may include a mixture of carbon black and silver (Ag).

[0069] The cathode coating layer (220) may further include other additives in addition to metal and carbon. The cathode coating layer (220) may further include at least one additive selected from the group consisting of, for example, binders, fillers, coating agents, dispersants, and ion-conducting aids.

[0070] For example, the loading amount of the cathode coating layer (220) is 0.1 mg / cm² 2 Up to 5 mg / cm² 2 It could be.

[0071] The negative electrode coating layer (220) may have a smaller thickness compared to the positive electrode active material layer (120). The thickness of the negative electrode coating 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 coating layer (220) may be, for example, 1 µm to 20 µm, 2 µm to 10 µm, or 3 µm to 7 µm. The thickness of the negative electrode coating layer (220) may be about 10 µm. If the thickness of the negative electrode coating layer (220) is excessively thin, lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210) may cause the negative electrode coating layer (220) to collapse, thereby degrading the cycle characteristics of the all-solid-state battery (10). If the thickness of the negative electrode coating layer (220) increases excessively, the energy density of the all-solid-state battery (10) decreases and the internal resistance of the all-solid-state battery (10) due to the negative electrode coating layer (220) increases, which may degrade the cycle characteristics of the all-solid-state battery (10).

[0072] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0073]

[0074] Referring to FIG. 1, the positive active material layer (120) may have a first width (WI1) in a first direction (D1). The negative coating layer (220) may have a second width (WI2) in a first direction (D1).

[0075] For example, the first width (WI1) of the positive active material layer (120) may be substantially the same as the second width (WI2) of the negative coating layer (220). In this specification, substantially the same width may be defined as the difference between the two widths being within 10%.

[0076] As another example, the first width (WI1) of the positive active material layer (120) may be smaller than the second width (WI2) of the negative coating layer (220).

[0077] Hereinafter, the solid electrolyte layer (300) of the present invention will be described in detail.

[0078]

[0079] solid electrolyte layer (300)

[0080] FIG. 2 is an enlarged view of a solid electrolyte layer (300) according to embodiments of the present invention. FIG. 3 is an enlarged view of a solid electrolyte layer (300) according to one embodiment of the present invention, and is an enlarged view of the M region of FIG. 2.

[0081] Referring to FIGS. 1 to 3, the solid electrolyte layer (300) is disposed between the anode layer (100) and the cathode layer (200) and may include a first solid electrolyte layer (SEL1), an adhesive layer (ADL), and a second solid electrolyte layer (SEL2).

[0082] The first solid electrolyte layer (SEL1) can be placed on the cathode coating layer (220).

[0083] The first solid electrolyte layer (SEL1) may include a first electrolyte particle (SE1). The first electrolyte particle (SE1) may include a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. The solid electrolyte included in the first solid electrolyte layer (SEL1) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the aforementioned positive electrode active material layer (120).

[0084] The first solid electrolyte layer (SEL1) of one embodiment may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by processing starting materials, such as Li2S or P2S5, by a melt quenching method or a mechanical milling method. Additionally, heat treatment may be performed after such processing. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. Furthermore, the solid electrolyte may include sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements among the sulfide-based solid electrolyte materials described above, for example. For example, the solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the molar ratio of Li2S and P2S5 is, for example, in the range of Li2S : P2S5 = 50 : 50 to 90 : 10.

[0085] Sulfide-based solid electrolytes are, for example, Li 7-x1 PS 6-x1 Cl x1 (0≤x1≤2), Li 7-x1 PS 6-x1 Br x1 (0≤x1≤2), and Li 7-x1 PS 6-x1 I x1 It may be a first argyrodite-type compound comprising one or more selected from (0≤x1≤2). In particular, the sulfide-based solid electrolyte may be a first argyrodite-type compound comprising one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0086] Alternatively, sulfide-based solid electrolytes are Li 7-a1 M1 a1 PS 6-c1 X1 c1It may be a first argyrodite-type compound containing (0≤a1≤2, 0≤c1≤2). Here, X1 may be F, Br, Cl, or a combination thereof. M1 may be scandium (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. there is.

[0087] The density of the first azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or higher for the first azyrodite-type solid electrolyte, the internal resistance of the lithium metal battery is reduced, and defects such as penetration and short circuit of the solid electrolyte film due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0088] The first solid electrolyte layer (SEL1) may further include a binder. The binder included in the first solid electrolyte layer (SEL1) is, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited to these. The binder of the first solid electrolyte layer (SEL1) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0089] The thickness (TK1) of the first solid electrolyte layer (SEL1) may be 15㎛ to 100㎛. For example, the thickness (TK1) of the first solid electrolyte layer (SEL1) may be 15㎛ to 90㎛, 15㎛ to 80㎛, 15㎛ to 70㎛, 15㎛ to 60㎛, 15㎛ to 50㎛, 20㎛ to 50㎛, or 30㎛ to 40㎛.

[0090] The first solid electrolyte layer (SEL1) may have a third width (WL1) in the first direction (D1). For example, the third width (WL1) of the first solid electrolyte layer (SEL1) may be substantially the same as the second width (WI2) of the cathode coating layer (220).

[0091] The second solid electrolyte layer (SEL2) can be placed on the lower surface of the positive active material layer (120).

[0092] The second solid electrolyte layer (SEL2) may include second electrolyte particles (SE2). The second electrolyte particles (SE2) may include a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics. The solid electrolyte included in the second solid electrolyte layer (SEL2) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the aforementioned positive electrode active material layer (120).

[0093] The second solid electrolyte layer (SEL2) of one embodiment may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by processing starting materials, such as Li2S or P2S5, by a melt quenching method or a mechanical milling method. Additionally, heat treatment may be performed after such processing. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. Furthermore, the solid electrolyte may include sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements among the sulfide-based solid electrolyte materials described above, for example. For example, the solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the molar ratio of Li2S to P2S5 is, for example, in the range of Li2S : P2S5 = 50 : 50 to 90 : 10.

[0094] Sulfide-based solid electrolytes are, for example, Li 7-x2 PS 6-x2 Cl x2 (0≤x2≤2), Li 7-x2 PS 6-x2 Br x2 (0≤x2≤2), and Li 7-x2 PS 6-x2 I x2 It may be a second argyrodite-type compound comprising one or more selected from (0≤x2≤2). In particular, the sulfide-based solid electrolyte may be a second argyrodite-type compound comprising one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0095] Alternatively, sulfide-based solid electrolytes are Li 7-a2 M2 a2 PS 6-c2 X2 c2It may be a second argyrodite-type compound containing (0≤a2≤2, (0≤c2≤2)). Here, X2 may be F, Br, Cl, or a combination thereof. M2 may be scandium (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. there is.

[0096] The density of the second azyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or higher for the second azyrodite-type solid electrolyte, the internal resistance of the lithium metal battery is reduced, and defects such as penetration and short circuit of the solid electrolyte film due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0097] The second solid electrolyte layer (SEL2) may further include a binder. The binder included in the second solid electrolyte layer (SEL2) is, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited to these. The binder of the second solid electrolyte layer (SEL2) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0098] The thickness (TK2) of the second solid electrolyte layer (SEL2) may be 15㎛ to 100㎛. For example, the thickness (TK1) of the first solid electrolyte layer (SEL1) may be 15㎛ to 90㎛, 15㎛ to 80㎛, 15㎛ to 70㎛, 15㎛ to 60㎛, 15㎛ to 50㎛, 20㎛ to 50㎛, or 30㎛ to 40㎛.

[0099] The second solid electrolyte layer (SEL2) may have a fourth width (WL2) in the first direction (D1). For example, the fourth width (WL2) of the second solid electrolyte layer (SEL2) may be substantially the same as the first width (WI1) of the positive active material layer (120).

[0100] An adhesive layer (ADL) may be disposed on the first solid electrolyte layer (SEL1). An adhesive layer (ADL) may be disposed on the lower surface of the second solid electrolyte layer (SEL2). An adhesive layer (ADL) may be disposed between the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2).

[0101] The thickness (TKA) of the adhesive layer (ADL) may be 0.01 μm to 20 μm. For example, the thickness (TKA) of the adhesive layer (ADL) may be 0.01 μm to 15 μm, or 0.01 μm to 10 μm. For example, the thickness (TKA) of the adhesive layer (ADL) may be about 0.01 μm, or about 0.1 μm, or about 1 μm, or about 10 μm.

[0102] The adhesive layer (ADL) may have a fifth width (WA) in the first direction (D1). For example, the fifth width (WA) of the adhesive layer (ADL) may be substantially the same as the third width (WL1) of the first solid electrolyte layer (SEL1). For example, the fifth width (WA) of the adhesive layer (ADL) may be substantially the same as the fourth width (WL2) of the second solid electrolyte layer (SEL2). For example, the fifth width (WA) of the adhesive layer (ADL), the third width (WL1) of the first solid electrolyte layer (SEL1), and the fourth width (WL2) of the second solid electrolyte layer (SEL2) may be substantially the same as each other.

[0103] The adhesive layer (ADL) is described in detail below.

[0104]

[0105] Adhesive layer (ADL)

[0106] Referring to FIG. 3, the adhesive layer (ADL) may include a cyclic polymer (CCP).

[0107] For example, the weight-average molecular weight (Mw) of the cyclic polymer (CCP) may be 1,000 to 300,000. For example, the weight-average molecular weight (Mw) of the cyclic polymer (CCP) may be 1,000 or more, 3,000 or more, 5,000 or more, or 10,000 or more. For example, the weight-average molecular weight (Mw) of the cyclic polymer (CCP) may be 300,000 or less, 100,000 or less, 80,000 or less, or 50,000 or less.

[0108] For example, the number average molecular weight (Mn) of the cyclic polymer (CCP) may be 1,000 to 300,000. For example, the number average molecular weight (Mn) of the cyclic polymer (CCP) may be 1,000 or more, 3,000 or more, 5,000 or more, or 10,000 or more. For example, the number average molecular weight (Mn) of the cyclic polymer (CCP) may be 300,000 or less, 100,000 or less, 80,000 or less, or 50,000 or less.

[0109] The cyclic polymer (CCP) may include a first repeating unit and a second repeating unit.

[0110] The first repeating unit can be represented by the following structural formula 1.

[0111] [Structural Formula 1]

[0112]

[0113] The above L1, the above L2, and the above L3 may each independently be a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group. For example, the above L1, the above L2, and the above L3 may each independently be a C1 to C3 alkylene group.

[0114] The above Y1 and the above Y2 may each independently be oxygen or sulfur. For example, the above Y1 and the above Y2 may each be oxygen.

[0115] The first repeating unit can impart adhesiveness to the solid electrolyte layer (300) and the freestanding solid electrolyte membrane (SEM). The first repeating unit can improve the ionic conductivity of the solid electrolyte layer (300) and the freestanding solid electrolyte membrane (SEM).

[0116] The second repeating unit can be represented by the following structural formula 2.

[0117] [Structural Formula 2]

[0118]

[0119] The above L4 may be a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkynylene group. For example, the above L4 may be a C1 to C10 alkylene group.

[0120] The second repeating unit can impart adhesiveness to the solid electrolyte layer (300) and the freestanding solid electrolyte membrane (SEM).

[0121] The first repeating unit and the second repeating unit may be bonded to each other by disulfide bonds (SS). Any one of the sulfur (S) atoms of the first repeating unit may be covalently bonded to any one of the sulfur (S) atoms of the second repeating unit. The remaining one of the sulfur (S) atoms of the first repeating unit may be covalently bonded to the remaining one of the sulfur (S) atoms of the second repeating unit.

[0122] The molar ratio of the first repeating unit and the second repeating unit in the cyclic polymer (CCP) may be 2:1 to 1:2. For example, the molar ratio of the first repeating unit and the second repeating unit in the cyclic polymer (CCP) may be 1.5:1 to 1:1.5, 1.5:1 to 1:1, 1:1 to 1:1.5, or 1:1.

[0123] The first repeating unit may include a plurality of first repeating units. The second repeating unit may include a plurality of second repeating units. Within the cyclic polymer (CCP), the first repeating unit and the second repeating unit may be arranged randomly.

[0124] For example, a cyclic polymer (CCP) can be represented by the following structural formula 3.

[0125] [Structural Formula 3]

[0126]

[0127] The above n may be 1 to 1000, and the above m may be 1 to 1000. For example, the above n may be 1 to 500, and the above m may be 1 to 500. Or, for example, the above n may be 1 to 300, and the above m may be 1 to 300. Or, for example, the above n may be 1 to 200, and the above m may be 1 to 200.

[0128] As another example, a cyclic polymer (CCP) can be represented by the following structural formula 4.

[0129] [Structural Formula 4]

[0130]

[0131] The sum of p and r may be 2 to 1000, and the sum of q and s may be 2 to 1000. For example, p may be 1 to 999 and r may be 1 to 999. q may be 1 to 999 and s may be 1 to 999.

[0132] For example, the sum of p and r may be 2 to 500, and the sum of q and s may be 2 to 500. For example, p may be 1 to 499, and r may be 1 to 499. q may be 1 to 499, and s may be 1 to 499.

[0133] Or, for example, the sum of p and r may be 2 to 300, and the sum of q and s may be 2 to 300. For example, p may be 1 to 299, and r may be 1 to 299. q may be 1 to 299, and s may be 1 to 299.

[0134] Or, for example, the sum of p and r may be 2 to 200, and the sum of q and s may be 2 to 200. For example, p may be 1 to 199, and r may be 1 to 199. q may be 1 to 199, and s may be 1 to 199.

[0135] As another example, a cyclic polymer (CCP) can be represented by the following structural formula 5.

[0136] [Structural Formula 5]

[0137]

[0138] The sum of the above u, the above w, and the above y may be 3 to 1000, and the sum of the above v, the above x, and the above z may be 3 to 1000. For example, the above e may be u to 998, the above w may be 1 to 998, and the above y may be 1 to 998. For example, the above v may be 1 to 998, the above x may be 1 to 998, and the above z may be 1 to 998.

[0139] For example, the sum of the above u, the above w, and the above y may be 3 to 500, and the sum of the above v, the above x, and the above z may be 3 to 500. For example, the above e may be u to 498, the above w may be 1 to 498, and the above y may be 1 to 498. For example, the above v may be 1 to 498, the above x may be 1 to 498, and the above z may be 1 to 498.

[0140] Alternatively, for example, the sum of the above u, the above w, and the above y may be 3 to 300, and the sum of the above v, the above x, and the above z may be 3 to 300. For example, the above e may be u to 298, the above w may be 1 to 298, and the above y may be 1 to 298. For example, the above v may be 1 to 298, the above x may be 1 to 298, and the above z may be 1 to 298.

[0141] Alternatively, for example, the sum of the above u, the above w, and the above y may be 3 to 200, and the sum of the above v, the above x, and the above z may be 3 to 200. For example, the above e may be u to 198, the above w may be 1 to 198, and the above y may be 1 to 198. For example, the above v may be 1 to 198, the above x may be 1 to 198, and the above z may be 1 to 198.

[0142] However, the structure of the cyclic polymer (CCP) is not limited to the examples described above and may further include various structures in which the first repeating unit and the second repeating unit are randomly arranged.

[0143]

[0144] The adhesive layer (ADL) according to the embodiments of the present invention may have adhesive properties. The adhesive layer (ADL) according to the embodiments of the present invention may be interposed between the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2) to bond them together. The adhesive layer (ADL) according to the embodiments of the present invention may bond the interface between the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2) and reduce the voids within the interface. By doing so, the performance (resistance, etc.) of an all-solid-state battery including the adhesive layer (ADL) according to the embodiments of the present invention can be improved. For example, the solid electrolyte layer (300) according to the embodiments of the present invention may have an interfacial resistance of 300 Ω or less and an ionic conductivity of 0.02 mS / cm or more.

[0145]

[0146] Method for manufacturing an all-solid-state battery

[0147] FIG. 4 is a flowchart illustrating a method for manufacturing an all-solid-state battery according to embodiments of the present invention. FIG. 5 to 11 are schematic diagrams illustrating each step of a method for manufacturing an all-solid-state battery according to an embodiment of the present invention.

[0148] Referring to FIG. 4, a method for manufacturing an all-solid-state battery according to embodiments of the present invention may include forming a negative electrode laminate (S100); forming a positive electrode laminate (S300); coating an adhesive composition (S600); and forming a composite (S900).

[0149]

[0150] Referring to FIG. 5, a cathode layer (200) and a first solid electrolyte layer (SEL1) can be stacked and pressed to form a cathode laminate (S100). The cathode layer (200) may include a cathode current collector (210) and a cathode coating layer (220). A cathode laminate can be formed by stacking the first solid electrolyte layer (SEL1) on the cathode layer (200) and then applying a first pressure.

[0151] Referring to FIG. 6, an anode layer (100) and a second solid electrolyte layer (SEL2) can be stacked and pressed to form an anode laminate (S300). The anode layer (100) may include an anode current collector (110) and an anode active material layer (120). An anode laminate can be formed by stacking a second solid electrolyte layer (SEL2) on the anode layer (100) and then applying a second pressure.

[0152] The present invention allows the first pressure and the second pressure to be controlled differently by manufacturing the anode laminate and the cathode laminate by applying an individual pressurization method. Through this, a relatively low pressure can be applied to the laminate among the anode laminate and the cathode laminate that has weak mechanical strength or severe structural imbalance, which may be damaged if pressurized at a high pressure.

[0153] The first pressure may be greater than the second pressure. For example, the first pressure may be defined as pressure applied toward the interior of the anode laminate from the upper and lower surfaces of the anode laminate. The second pressure may be defined as pressure applied toward the interior of the cathode laminate from the upper and lower surfaces of the cathode laminate.

[0154] Forming the above-mentioned anode laminate and cathode laminate may include a pressurization process in which a roll press is applied. However, this is not necessarily limited to this method, and any pressurization process applicable in the relevant technical field may be applied. For example, pressurization processes such as hydraulic plate press and warm isostatic press may be applied.

[0155] When a roll press is applied during the formation process of the anode laminate, the line pressure of the first pressure may be 1 ton / cm to 5 ton / cm. Specifically, the line pressure of the first pressure may be 1 ton / cm to 4 ton / cm, 1 ton / cm to 3 ton / cm, or 1 ton / cm to 2.5 ton / cm.

[0156] When a roll press is applied during the formation process of the above cathode laminate, the line pressure of the second pressure may be 1 ton / cm to 4 ton / cm. Specifically, the line pressure of the second pressure may be 1 ton / cm to 3 ton / cm, 1 ton / cm to 2.5 ton / cm, or 1 ton / cm to 2 ton / cm.

[0157] The above pressurization process may be carried out at a relatively high temperature. Specifically, the above pressurization process may be carried out at 60 to 150 ℃, at 80 to 130 ℃, and at 100 to 125 ℃.

[0158] Forming the anode laminate and the cathode laminate may include a preheating process prior to the pressurization process. Specifically, the anode laminate and the cathode laminate may be preheated to ±10°C and ±5°C of the temperature at which the pressurization process is performed. The preheating process can prevent damage to the anode laminate and the cathode laminate caused by rapid temperature changes during the high-temperature pressurization process.

[0159] The order of forming the cathode stack (S100) and forming the anode stack (S300) is not limited. For example, the cathode stack may be formed first (S100), and then the anode stack may be formed (S300). For another example, the anode stack may be formed first (S300), and then the cathode stack may be formed (S100).

[0160]

[0161] Referring to FIGS. 7 to 9, coating an adhesive composition (S600) may include preparing a cyclic polymer (CCP); preparing an adhesive composition by mixing the cyclic polymer (CCP) and a solvent (S650); and coating the adhesive composition (S670).

[0162] The process of manufacturing a cyclic polymer (CCP) may include mixing a first reactant, a second reactant, and triethylamine (TEA) to form a first mixture; adding hydrogen peroxide to the first mixture to form a second mixture; obtaining a precipitate from the second mixture; and washing and drying the precipitate.

[0163] In forming the first mixture, the first reactant may be represented by the following structural formula 6. The first repeating unit described above may be derived from the first reactant.

[0164] [Structural Formula 6]

[0165]

[0166] The above L1, the above L2, and the above L3 may each independently be a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group. For example, the above L1, the above L2, and the above L3 may each independently be a C1 to C3 alkylene group.

[0167] The above Y1 and the above Y2 may each independently be oxygen or sulfur. For example, the above Y1 and the above Y2 may each be oxygen.

[0168] The second reactant can be represented by the following structural formula 7. The second repeating unit described above may be derived from the second reactant.

[0169] [Structural Formula 7]

[0170]

[0171] The above L4 may be a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkynylene group. For example, the above L4 may be a C1 to C10 alkylene group.

[0172] The molar ratio of the first reactant and the second reactant may be 2:1 to 1:2. For example, the molar ratio of the first reactant and the second reactant may be 1.5:1 to 1:1.5, 1.5:1 to 1:1, 1:1 to 1:1.5, or 1:1.

[0173] Triethylamine (TEA) can extract hydrogen (H) bonded to sulfur (S) atoms of the first or second reactant. Triethylamine (TEA) may be added in a mole amount at least twice the total mole amount of the first and second reactants. By doing so, the first or second reactant may become a dianion. The first mixture may contain the dianion of the first reactant or the dianion of the second reactant.

[0174] In forming the second mixture, hydrogen peroxide can oxidize the dianion of the first reactant or the dianion of the second reactant in the first mixture. Hydrogen peroxide may be added in excess for sufficient oxidation. For example, hydrogen peroxide may be added dropwise to the second mixture. By doing so, the dianion can become a diradical. The second mixture may contain the diradical of the first reactant or the diradical of the second reactant. The diradical of the first reactant and the diradical of the second reactant may react with each other to form a disulfide bond (SS).

[0175] Hydrogen peroxide may be diluted. For example, the hydrogen peroxide may be 10% by weight to 35% by weight hydrogen peroxide.

[0176] For example, forming the second mixture may be performed under conditions of bubbling air. For example, forming the second mixture may be performed for 1 to 3 hours.

[0177] The second mixture may contain a precipitate. The precipitate may contain a cyclic polymer (CCP). The precipitate may be obtained by decanting the supernatant of the second mixture.

[0178] In washing and drying the precipitate, the obtained precipitate may be washed with distilled water or an organic solvent. For example, the organic solvent may include acetone, methanol, etc.

[0179] By drying the washed precipitate, a cyclic polymer (CCP) can be obtained.

[0180] Referring to FIG. 7, an adhesive composition (SOL1) can be prepared by mixing a cyclic polymer (CCP) and a solvent (S650a).

[0181] The concentration of the cyclic polymer (CCP) in the adhesive composition (SOL1) may be 0.1% by weight to 50% by weight. For example, the concentration of the cyclic polymer (CCP) in the adhesive composition (SOL1) may be 0.1% by weight to 20% by weight, 0.1% by weight to 10% by weight, 0.1% by weight to 1% by weight, or 10% by weight to 50% by weight.

[0182] The solvent may include at least one selected from the group consisting of dichloromethane (methylene chloride), acetonitrile, and tetrahydrofuran.

[0183] Mixing is generally not limited to any method that allows the components to be uniformly mixed with one another.

[0184] The adhesive composition (SOL1) may be coated on the surface of at least one of the first solid electrolyte layer and the second solid electrolyte layer (S670, see FIG. 8 and FIG. 9).

[0185] Coating can be performed by a spray method. The spray method can be performed using a spray coating device (CTR). The spray method allows the adhesive composition (SOL1) to be coated thinly and uniformly on the solid electrolyte layers (SEL1, SEL2 in FIG. 12 and 13) without direct contact with the solid electrolyte layers. As a result, a coating layer (CTL1 in FIG. 8 and 9) can be formed on the solid electrolyte layers (SEL1, SEL2).

[0186] The solid electrolyte layers (SEL1, SEL2) may include a plurality of pores. The adhesive composition (SOL1) may penetrate between the plurality of pores. For example, if the adhesive composition (SOL1) is coated on the solid electrolyte layers (SEL1, SEL2), a layer in which the adhesive composition (SOL1) and the solid electrolyte layers (SEL1, SEL2) coexist may be formed. That is, the coating layer (CTL1) may include a layer in which the adhesive composition (SOL1) and the solid electrolyte layers (SEL1, SEL2) coexist.

[0187] Spray coating can be performed by placing the object to be coated on a support plate. As an example, the support plate may include a heating element. The heating element can control the temperature of the support plate.

[0188] For example, the support plate can rotate. By doing so, the support plate can form a uniform coating layer. For example, the rotation speed of the support plate may be from 0 rpm to 10,000 rpm. For example, the rotation speed of the support plate may be from 10 rpm to 10,000 rpm or from 50 rpm to 8,000 rpm. If the rotation speed of the support plate satisfies the range described above, the adhesive composition can be smoothly supplied to the solid electrolyte layers (SEL1, SEL2) and a uniform coating layer can be formed. As another example, the rotation of the support plate may be omitted.

[0189] Spray coating can be performed in a hydrogen atmosphere, a nitrogen atmosphere, or an inert atmosphere.

[0190] For example, referring to FIG. 8, an adhesive composition (SOL1) can be coated on the surface of a first solid electrolyte layer (SEL1). Thus, a coating layer (CTL1) can be formed on the first solid electrolyte layer (SEL1), and a coated cathode laminate can be formed (S670a).

[0191] As another example, referring to FIG. 9, the adhesive composition (SOL1) can be coated on the surface of the second solid electrolyte layer (SEL2). Thus, a coating layer (CTL1) can be formed on the second solid electrolyte layer (SEL2), and a coated anode laminate can be formed (S670b).

[0192] For example, this step may include drying. That is, this step may include drying after spray coating. The drying temperature may be controlled according to the characteristics of the solvent. For example, the drying temperature may be 60°C to 80°C. When the drying temperature satisfies the range described above, the solvent in the coating layer (CTL1) may evaporate.

[0193]

[0194] Referring to FIGS. 10 and 11, a combination can be formed by stacking and pressing a cathode stack and an anode stack (S900). Thus, a combination (all-solid-state battery of FIG. 1) in which an anode layer (100), a solid electrolyte layer (300), and a cathode layer (200) are combined can be manufactured. The all-solid-state battery may have a cross-section as shown in the enlarged view according to FIG. 3.

[0195] For example, referring to FIG. 10, the coated cathode laminate of FIG. 8 can be laminated and pressed with the anode laminate to form a combined structure. For another example, referring to FIG. 11, the coated anode laminate of FIG. 9 can be laminated and pressed with the cathode laminate to form a combined structure.

[0196] The anode laminate, the cathode laminate, and the coating layer (CTL1) can be pressurized to a third pressure. By doing so, the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2) can be bonded to each other.

[0197] This step may include a pressurization process in which a hydraulic plate press is applied. However, it is not necessarily limited to this method, and any pressurization process applicable in the relevant technical field may be applied. For example, pressurization processes such as roll press and warm isostatic press may be applied. As an example, the third pressure may be defined as the pressure applied from the upper and lower surfaces of the assembly toward the interior of the assembly.

[0198] The third pressure may be 2 MPa or higher. Specifically, the third pressure may be 2.5 MPa or higher, 3 MPa or higher, or 3.5 MPa or higher. The third pressure may be 100 MPa or lower. Specifically, the third pressure may be 20 MPa or lower, 10 MPa or lower, 5 MPa or lower, or 4 MPa or lower.

[0199] For example, the pressurization process may be carried out at a relatively high temperature. For example, the pressurization process may be performed at a temperature of 40°C to 180°C. For example, the pressurization process may be performed at a temperature of 50°C to 170°C, or 60°C to 160°C. When the temperature satisfies the range described above, the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2) may be bonded by an adhesive layer (ADL), and the adhesive layer (ADL) may reduce voids within the interface between the first solid electrolyte layer (SEL1) and the second solid electrolyte layer (SEL2). In addition, the performance (resistance, etc.) of the all-solid-state battery may be improved.

[0200]

[0201] The present invention will be explained in more detail below through examples. However, these examples are intended to illustrate the invention and the scope of the invention is not limited to these examples.

[0202]

[0203] Examples

[0204] Preparation Example 1: Preparation of Cyclic Polymer (CCP)

[0205] A cyclic polymer (CCP) comprising a first repeating unit represented by the following structural formula 1-1 and a second repeating unit represented by the following structural formula 2-1 was prepared.

[0206] [Structural Formula 1-1]

[0207]

[0208] [Structural Formula 2-1]

[0209]

[0210] A cyclic polymer (CCP) was prepared by the following method. A first mixture was formed by mixing a first reactant represented by structural formula 6-1 below, a second reactant represented by structural formula 7-1 below, and triethylamine (TEA) in a molar ratio of 1:1:4. Under air bubbling conditions, 30 wt% hydrogen peroxide was added dropwise to the first mixture over 45 minutes, followed by stirring for 2 hours to form a second mixture. The supernatant of the second mixture was removed to obtain a precipitate. The precipitate was washed with distilled water and acetone and dried to prepare a cyclic polymer (CCP).

[0211] [Structural Formula 6-1]

[0212]

[0213] [Structural Formula 7-1]

[0214]

[0215]

[0216] Preparation Example 2: Preparation of adhesive composition (SOL)

[0217] An adhesive composition (SOL1) was prepared by mixing the cyclic polymer (CCP) of Preparation Example 1 and a solvent (dichloromethane, acetonitrile, tetrahydrofuran, etc.). The first compound (MCL1) and the second compound (MCL2) were mixed in a molar ratio of 2:1. The concentration of the cyclic polymer (CCP) in the adhesive composition (SOL1) was 0.2 to 1 wt%.

[0218]

[0219] Preparation Example 3: Preparation of the cathode layer

[0220] A SUS foil with a thickness of 10 μm was prepared as a cathode current collector. Additionally, carbon black (CB) with a primary particle size of approximately 30 nm and silver (Ag) particles with an average particle size (D50) of approximately 60 nm were prepared as cathode coating layer materials. 4 g of a mixed powder, prepared by mixing carbon black (CB) and silver (Ag) particles in a weight ratio of 3:1, was placed in a container, and 4 g of an NMP solution containing 7 wt% of PVDF binder (Kureha #9300) was added to prepare a mixed solution. Subsequently, a slurry was prepared by stirring the mixed solution while gradually adding NMP to it. The prepared slurry was applied to a Ni sheet using a bar coater and dried in air at 80°C for 10 minutes. The resulting laminate was vacuum dried at 40°C for 10 hours. The surface of the cathode coating layer of the laminate was flattened by cold rolling the dried laminate. The cathode layer was fabricated by the above process. The thickness of the cathode coating layer included in the cathode layer was approximately 7 μm. The area of ​​the cathode coating layer and the cathode current collector were the same.

[0221]

[0222] Preparation Example 4: Preparation of the anode layer

[0223] LiNi coated with Li2O-ZrO2 (LZO) as a cathode active material 0.8 Co 0.15 Mn 0.05O2 (NCM) was prepared. The LZO-coated cathode active material was prepared according to the method disclosed in Korean Patent Publication No. 10-2016-0064942. Li6PS5Cl, an argyrodite-type crystal (D50 = 0.5 μm, crystalline), was prepared as the solid electrolyte. Polytetrafluoroethylene (PTFE) binder was prepared as the binder. Carbon nanofiber (CNF) was prepared as the conductive agent. A slurry was formed by mixing these materials with a xylene solvent in a weight ratio of cathode active material : solid electrolyte : conductive agent : binder = 84 : 11.5 : 3 : 1.5, and then vacuum-dried at 40°C for 8 hours to produce a cathode sheet. Anode sheets manufactured were placed on the cross-section of an anode current collector made of carbon-coated aluminum foil on one side, and an anode layer was manufactured by a heated roll press at 85°C. The total thickness of the anode layer was approximately 120 μm. The thickness of the anode active material layer was approximately 107 μm, and the thickness of the carbon-coated (thickness 1 mm) aluminum foil was approximately 13 μm. The area of ​​the anode active material layer and the anode current collector were the same.

[0224]

[0225] Preparation Example 5: Preparation of a solid electrolyte layer (dry)

[0226] A mixture was prepared by adding 1 part by weight of a polytetrafluoroethylene (PTFE) first binder and 1 part by weight of a polyvinylidene fluoride (PVDF) second binder to an argyrodite-type crystal Li6PS5Cl sulfide-based solid electrolyte (D50 = 1~10 μm, crystalline) with respect to 98 parts by weight of the solid electrolyte into a grind mixer and mixing. The prepared mixture was added to a mortar heated to 80°C and stirred to prepare a dough. The prepared dough was passed through a roller and formed into a sheet shape to prepare a solid electrolyte film of uniform thickness. A solid electrolyte layer was manufactured by the above process. The above solid electrolyte layer was prepared as a solid electrolyte layer (SEL2) having substantially the same area as the anode layer and a solid electrolyte layer (SEL1) having substantially the same area as the cathode layer. The elastic modulus of the sulfide-based solid electrolyte was about 15 GPa to 30 GPa.

[0227]

[0228] Preparation Example 6: Preparation of an all-solid-state battery

[0229] An all-solid-state battery including an adhesive layer was prepared. The all-solid-state battery including the adhesive layer was manufactured by the following method.

[0230] An anode layer and a solid electrolyte layer (SEL2) were laminated and pressed using a roll press method. An anode laminate was manufactured by applying a linear pressure of 2.5 ton / cm at 120°C. A cathode layer and a solid electrolyte layer (SEL1) were laminated and pressed using a roll press method. A cathode laminate was manufactured by applying a linear pressure of 2.0 ton / cm at 120°C.

[0231] An adhesive composition was spray-coated onto a cathode laminate. The cathode laminate was placed on a temperature-controlled support plate, and the adhesive composition was sprayed under a hydrogen atmosphere. After spray coating, it was dried at a temperature of 60°C.

[0232] A composite was formed by applying pressure to the coated cathode laminate and anode laminate using a roll press method. The pressure was applied at a temperature of 160°C.

[0233]

[0234] Preparation Example 7: Preparation of a symmetrical cell

[0235] A cathode layer and a solid electrolyte layer (SEL1) were laminated and pressed using a roll press method. A cathode laminate was manufactured by applying a linear pressure of 2.0 ton / cm at 120°C.

[0236] An adhesive composition was spray-coated onto a cathode laminate. The cathode laminate was placed on a temperature-controlled support plate, and the adhesive composition was sprayed under a hydrogen atmosphere. After spray coating, it was dried at a temperature of 60°C.

[0237] Another cathode laminate was placed on the coating layer of the above-mentioned coated cathode laminate, and a symmetric cell was manufactured by applying pressure using a roll press method. The pressure was applied at a temperature of 160°C.

[0238]

[0239] Comparative example

[0240] A symmetric cell that does not contain an adhesive layer (ADL) was prepared.

[0241] It was prepared in the same manner as Example 1, except that the adhesive composition was not coated.

[0242]

[0243] Experimental Example 1: Analysis of the adhesive layer

[0244] The adhesive layer (ADL) in the all-solid-state battery and symmetric cell according to Example 1 was a soft, off-white film. The thickness of the adhesive layer (ADL) was about 10 μm.

[0245] The molecular weight of the cyclic polymer (CCP) constituting the adhesive layer was analyzed by gel permeation chromatography. The results are shown in Table 1.

[0246]

[0247] Classification MnMwPDI Cyclic Polymer (CCP) 1700 233 74 11.8

[0248]

[0249] Structure of cyclic polymers (CCP) 1 It was confirmed by H NMR. The results were as follows.

[0250] 1 H NMR (400 MHz, CDCl3): δ = 3.71 (t, 4H), 3.61 (s, 4H), 2.85 (q, 4H), 2.67 (m, 4H), 1.66 (m, 4H), 1.38 (br m, 4H).

[0251]

[0252] Experimental Example 2: Performance Analysis of All-Solid State Batteries

[0253] The interfacial resistance of all-solid-state batteries containing freestanding solid electrolyte membranes according to the examples and comparative examples was measured using an impedance analyzer (Solartron 1260A Impedance / Gain-Phase Analyzer) according to the 2-probe method. The interfacial resistance was measured using a symmetric cell containing a freestanding solid electrolyte membrane according to the examples and comparative examples. The interfacial resistance was measured under conditions of a temperature of 25°C, a frequency range of 0.1 Hz to 1 MHz, and a voltage bias of 10 mV.

[0254] The ionic conductivity of the all-solid-state battery according to the examples and comparative examples was evaluated at 25°C. The ionic conductivity was measured using a symmetric cell according to the examples and comparative examples. The ionic conductivity was calculated by substituting the resistance value obtained from the arc of the Nyquist plot according to the impedance analysis into the following equation.

[0255] [ceremony]

[0256] Ionic conductivity (σ) = I / (R A) (I: thickness of solid electrolyte layer, R: resistance, A: electrode area)

[0257] The results are shown in Table 2.

[0258]

[0259] Interfacial Resistance (Ω) Ionic Conductivity (mS / cm) Example 25 Ω 0.181 Comparative Example 50 Ω 0.009

[0260]

[0261] Referring to Table 2, the symmetric cell according to the example had a small interfacial resistance. Thus, it was confirmed that the freestanding solid electrolyte membrane can bond the interfaces within the all-solid-state battery, reduce the voids within the interfaces, and provide a solid electrolyte layer and an all-solid-state battery with low resistance.

[0262] In addition, the symmetric cell according to the example had excellent ionic conductivity. Thus, it was confirmed that the freestanding solid electrolyte membrane can improve the ionic conductivity of the solid electrolyte layer and the all-solid-state battery.

[0263]

[0264] Although embodiments of the present invention have been described above with reference to the attached drawings, the present invention may be implemented in other specific forms without altering its technical concept or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Includes cyclic polymers, but, The above cyclic polymer comprises a first repeating unit represented by the following structural formula 1 and a second repeating unit represented by the following structural formula 2, and The first repeating unit and the second repeating unit are joined to each other by disulfide bonds, Adhesive composition: [Structural Formula 1] The above L1, the above L2 and the above L3 are each independently a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group, and The above Y1 and the above Y2 are each independently oxygen or sulfur, and [Structural Formula 2] The above L4 is a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkylene group.

2. In Paragraph 1, The molar ratio of the first repeating unit and the second repeating unit is 2:1 to 1:2, Adhesive composition.

3. In Paragraph 1, The weight-average molecular weight of the above cyclic polymer is 1,000 to 300,000, Adhesive composition.

4. In Paragraph 1, In the above structural formula 1, L1, L2, and L3 are each independently C1 to C3 alkylene groups, and The above Y1 and the above Y2 are each oxygen, Adhesive composition.

5. In Paragraph 1, In the above structural formula 2, the L4 is a C1 to C10 alkylene group, Adhesive composition.

6. In Paragraph 1, The above cyclic polymer is represented by the following structural formula 3, Adhesive composition: [Structural Formula 3] The above n is 1 to 1000, and The above m is 1 to 1000.

7. In Paragraph 1, The above cyclic polymer is represented by the following structural formula 4, Adhesive composition: [Structural Formula 4] The sum of the above p and the above r is 2 to 1000, and The sum of the above q and the above s is 2 to 1000.

8. In Paragraph 1, The above cyclic polymer is represented by the following structural formula 5, Adhesive composition: [Structural Formula 5] The sum of the above u, the above w, and the above y is 3 to 1000, and The sum of the above v, the above x, and the above z is 3 to 1000.

9. In Paragraph 1, It further contains a solvent, The above solvent comprises at least one selected from the group consisting of dichloromethane, acetonitrile, and tetrahydrofuran, Adhesive composition.

10. A positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, wherein The above solid electrolyte layer is: A first solid electrolyte layer comprising first electrolyte particles; A second solid electrolyte layer comprising second electrolyte particles; and It includes an adhesive layer interposed between the first and second solid electrolyte layers to bond them together, and The above adhesive layer is: Includes cyclic polymers, The above cyclic polymer comprises a first repeating unit represented by the following structural formula 1 and a second repeating unit represented by the following structural formula 2, and The first repeating unit and the second repeating unit are joined to each other by disulfide bonds, All-solid-state battery: [Structural Formula 1] The above L1, the above L2 and the above L3 are each independently a single bond, a C1 to C10 alkylene group, a C2 to C10 alkenylene group, or a C2 to C10 alkynylene group, and The above Y1 and the above Y2 are each independently oxygen or sulfur, and [Structural Formula 2] The above L4 is a single bond, a C1 to C20 alkylene group, a C2 to C20 alkenylene group, or a C2 to C20 alkylene group.

11. In Paragraph 10, The molar ratio of the first repeating unit and the second repeating unit is 2:1 to 1:2, All-solid-state battery.

12. In Paragraph 10, The weight-average molecular weight of the above cyclic polymer is 1,000 to 300,000, All-solid-state battery.

13. In Paragraph 10, The first electrolyte particle and the second electrolyte particle each contain an azirodite-type compound, and The above azirodite-type compound is Li 7-a M a PS 6-c X c Includes, The above X is Cl, Br, or a combination thereof, and Each of the above a and c is a real number between 0 and 2, All-solid-state battery.

14. In Paragraph 10, The above solid electrolyte layer has an interfacial resistance of 300 Ω or less and an ionic conductivity of 0.02 mS / cm or more, All-solid-state battery.

15. Forming a cathode laminate by stacking and pressing a cathode layer and a first solid electrolyte layer; Forming an anode laminate by stacking and pressing an anode layer and a second solid electrolyte layer; Coating an adhesive composition on at least one surface of the first solid electrolyte layer and the second solid electrolyte layer; and The method includes stacking and pressing the above cathode laminate and the above anode laminate to form a composite body, wherein The above adhesive composition is the adhesive composition described in claim 1, Method for manufacturing an all-solid-state battery.

16. In Paragraph 15, Coating the adhesive composition comprises coating the adhesive composition on the surface of the first solid electrolyte layer to form a coated cathode laminate, and Forming the above-mentioned composite comprises stacking and pressing the coated cathode laminate and the anode laminate to form the composite. Method for manufacturing an all-solid-state battery.

17. In Paragraph 15, Coating the adhesive composition comprises coating the adhesive composition on the surface of the second solid electrolyte layer to form a coated anode laminate. Forming the above-mentioned composite comprises stacking and pressing the coated anode laminate and the cathode laminate to form the composite. Method for manufacturing an all-solid-state battery.

18. In Paragraph 15, The above coating is performed using a spray method, Method for manufacturing an all-solid-state battery.

19. In Paragraph 15, The above coating comprises drying at a temperature of 60°C to 80°C, Method for manufacturing an all-solid-state battery.

20. In Paragraph 15, The pressure of forming the above-mentioned assembly comprises at least one selected from the group consisting of roll pressure, heated hydrostatic pressure, and plate pressure. Method for manufacturing an all-solid-state battery.

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