Composite substrate for all-solid-state battery and all-solid-

Abstract

Provided are a composite substrate for an all-solid-state battery having excellent sulfation resistance and high-temperature life characteristics, and a negative electrode including the same.SOLUTION: The present disclosure relates to a composite substrate for an all-solid-state battery, a negative electrode for an all-solid-state battery including the same, and an all-solid-state battery. More specifically, the composite substrate for an all-solid-state battery of the present disclosure includes a polymer layer, a first nickel alloy layer on a first surface of the polymer layer, and a second nickel alloy layer on a second surface of the polymer layer, wherein each of the first and second nickel alloy layers includes a nickel-iron binary alloy.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a composite substrate for an all-solid-state battery and an all-solid-state battery including the same. [Background technology]

[0002] Recently, 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 the fields of information-related equipment and communication devices, but also in the automotive field. Safety is of particular importance in the automotive field, where batteries are closely related to life.

[0003] However, currently available lithium-ion batteries contain electrolytes containing flammable organic dispersion media, which can lead to overheating and fires in the event of a short circuit. In response to these issues, all-solid-state batteries have been proposed, in which the electrolyte is replaced with a solid electrolyte. By eliminating the use of flammable organic dispersion media, all-solid-state batteries can significantly reduce the risk of fire or explosion in the event of a short circuit. Therefore, these all-solid-state batteries offer significantly improved safety compared to lithium-ion batteries that use liquid electrolytes. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a composite substrate for an all-solid-state battery having excellent sulfation resistance and high-temperature life characteristics, and a negative electrode including the same.

[0005] Another problem to be solved by the present invention is to provide an all-solid-state battery having excellent sulfation resistance and high-temperature life characteristics. [Means for solving the problem]

[0006] A composite substrate for an all-solid-state battery according to the concepts of the present invention can include a polymer layer, a first nickel alloy layer on a first surface of the polymer layer, and a second nickel alloy layer on a second surface of the polymer layer, wherein each of the first and second nickel alloy layers can include a nickel-iron binary alloy.

[0007] According to another aspect of the present invention, an anode for an all-solid-state battery can include a composite substrate and an anode coating layer on the composite substrate, the composite substrate including a polymer layer and a first nickel alloy layer on the polymer layer, the first nickel alloy layer including a nickel-iron binary alloy.

[0008] According to another aspect of the present invention, an all-solid-state battery can include a composite substrate, an anode layer including an anode coating layer on the composite substrate, a solid electrolyte layer on the anode layer, and a cathode layer on the solid electrolyte layer. The composite substrate can include a polymer layer and a first nickel alloy layer on the polymer layer, and the first nickel alloy layer can include a nickel-iron binary alloy. [Effects of the Invention]

[0009] The composite substrate for an all-solid-state battery and the negative electrode including the same according to the present invention have excellent resistance to sulfation by a sulfide-based solid electrolyte.

[0010] The all-solid-state battery according to the present invention has excellent sulfation resistance and high-temperature life characteristics for a sulfide-based solid electrolyte. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a composite substrate according to an embodiment of the present invention. [Figure 5]1 is a cross-sectional view of a composite substrate according to an embodiment of the present invention. [Figure 6A] 1 is a flowchart illustrating a method for manufacturing a composite substrate according to an embodiment of the present invention. [Figure 6B] 1 is a cross-sectional view illustrating a method for manufacturing a composite substrate according to an embodiment of the present invention. [Figure 6C] 1 is a cross-sectional view illustrating a method for manufacturing a composite substrate according to an embodiment of the present invention. [Figure 6D] 1 is a cross-sectional view illustrating a method for manufacturing a composite substrate according to an embodiment of the present invention. [Figure 7A] 1 shows the results of evaluating the cyclic voltage and current of the half cell according to Comparative Example 1 in response to charge-discharge cycles. (i) is a photograph of the copper foil (negative electrode current collector) before charge-discharge, and (ii) is a photograph of the copper foil (negative electrode current collector) after 30 charge-discharge cycles. [Figure 7B] 1 shows the results of evaluating the cyclic voltage and current of the half cell according to Comparative Example 2 in response to charge-discharge cycles. (i) is a photograph of the nickel foil (negative electrode current collector) before charge-discharge, and (ii) is a photograph of the nickel foil (negative electrode current collector) after 30 charge-discharge cycles. [Figure 8A] 1 shows the results of evaluating the cyclic voltage and current of the half cell according to Comparative Example 2 in response to charge and discharge cycles. [Figure 8B] 10 shows the results of cyclic voltage / current evaluation of the half cell according to Comparative Example 3 in response to charge / discharge cycles. [Figure 8C] 1 shows the results of cyclic voltage / current evaluation of the half cell according to Example 1 in response to charge / discharge cycles. [Figure 8D] 1 shows the results of cyclic voltage-current evaluation of the half cell according to Example 2 in response to charge-discharge cycles. [Figure 8E] 10 shows the results of cyclic voltage-current evaluation of the half cell according to Example 3 in response to charge-discharge cycles. [Figure 8F] 10 shows the results of cyclic voltage-current evaluation of the half cell according to Example 4 in response to charge-discharge cycles. DETAILED DESCRIPTION OF THE INVENTION

[0012] In order to fully understand the configuration 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, and can be embodied in various forms and can undergo various modifications. However, the description of the present embodiments is provided to complete the disclosure of the present invention and to allow those skilled in the art to understand the scope of the invention.

[0013] In this specification, when a certain 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 can be present between them. Also, in the drawings, the thickness of the components is exaggerated for the sake of efficient explanation of the technical content. Parts designated with the same reference numerals throughout the specification refer to the same components.

[0014] Unless otherwise specified herein, the singular can also include the plural. Furthermore, unless otherwise specified, "A or B" can mean "including A, including B, or including A and B." As used in the specification, "comprises" and / or "comprising" does not exclude the presence or addition of one or more other elements to the referenced element.

[0015] As used herein, "combinations thereof" can mean mixtures, laminates, composites, copolymers, alloys, blends, reaction products, and the like of compositions.

[0016] Unless otherwise defined herein, particle size refers to the average particle size. Furthermore, particle size refers to the average particle size (D50), which refers to the diameter of particles with a cumulative volume of 50% in a particle size distribution. The average particle size (D50) can be measured by methods well known to those skilled in the art, such as using a particle size analyzer or a transmission electron microscope (TEM) or scanning electron microscope (SEM) image. Alternatively, the average particle size (D50) can be measured using a measuring device that uses dynamic light scattering, and data analysis can be performed to count the number of particles in each particle size range, after which the average particle size (D50) can be calculated. Alternatively, the average particle size (D50) can be measured using a laser diffraction method. More specifically, when measuring by the laser diffraction method, the particles to be measured are dispersed in a dispersion medium, then 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. The average particle size (D50) based on 50% of the particle size distribution in the measuring device can then be calculated.

[0017] FIG. 1 is a cross-sectional view illustrating an all-solid-state battery according to an embodiment.

[0018] Referring to FIG. 1, the all-solid-state battery 10 may include an anode layer 200, a solid electrolyte layer 300 on the anode layer 200, and a cathode layer 100 on the solid electrolyte layer 300.

[0019] The positive electrode layer 100 may include 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.

[0020] The positive electrode current collector 110 may provide a reference surface on which the positive electrode active material layer 120 is disposed. The positive electrode current collector 110 may include, for example, a plate or foil including 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.

[0021] 1, in one embodiment of the present invention, the positive electrode current collector 110 may be omitted. Although not shown, a carbon layer having a thickness of 0.1 μm to 4 μm may be further disposed between the positive electrode current collector 110 and the positive electrode active material layer 120 to increase the adhesive strength between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0022] The positive electrode active material may include a material capable of reversibly absorbing and desorbing lithium ions. The positive electrode active material may include a plurality of particles. Examples of the positive electrode active material include, but are not 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 positive electrode active materials may be used alone or in combination.

[0023] 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 O2-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 Mr 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 Mr 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 HAVE BEEN 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 Mr 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 aMn2GbO4 (0.90≦a≦1, 0.001≦b≦0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≦f≦2), Li 3-f A compound represented by any one of Fe2(PO4)3 (0≦f≦2), LiFePO4. In such 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.

[0024] The positive electrode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the above-mentioned lithium transition metal oxides. The "layered rock salt type structure" may be, 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 the direction, and 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 are shifted from each other by about half the ridge of a unit lattice. Lithium transition metal oxides with such a layered rock salt structure are, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mnz It can be a ternary lithium transition metal oxide such as O2(NCM) (0 < x < 1, 0 < y < 1, 0 < z < 1, x + y + z = 1). When the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt structure, the energy density of the all-solid-state battery 10 can be increased and the thermal stability can be improved.

[0025] The above-described compound contained in the positive electrode active material can be covered by a coating layer (not shown). The positive electrode active material can also be used as a mixture of the above-described compound and a compound with a coating layer added. On the other hand, the coating layer added to the surface of the positive electrode active material can include, for example, oxides, hydroxides, oxyhydroxides, oxycarbonates, or hydroxycarbonates of the following coating elements. The compound forming such a coating layer is amorphous or crystalline. The coating elements contained in the coating layer can include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The coating layer can include, for example, Li2O-ZrO2 (LZO), etc. The coating layer formation method is selected within a range that does not adversely affect the physical properties of the positive electrode active material (PAM). The coating layer formation method is, for example, spray coating, dipping method, etc.

[0026] When the positive electrode active material contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, it is possible to increase the capacity density of the all-solid-state battery 10 and reduce the metal elution of the positive electrode active material (PAM) in the charged state. As a result, the cycle characteristics of the all-solid-state battery 10 in the charged state are improved. On the other hand, "cycle characteristics" is a characteristic indicating the degree to which the all-solid-state battery 10 deteriorates due to charge / discharge of the all-solid-state battery 10. An all-solid-state battery 10 with high cycle characteristics has 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 can have a large degree of deterioration of the all-solid-state battery 10 due to charge / discharge.

[0027] The positive electrode active material can have a particle shape such as a sphere, ellipsoid, etc. The particle size and content of the positive electrode active material are not particularly limited.

[0028] The solid electrolyte may have a particle shape. The solid electrolyte may be dispersed among the positive electrode active materials. The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity. Examples of sulfide-based solid electrolytes 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, and Li2S-P2S5-Z. m S n (m and n are positive numbers, and the capital letter "Z" is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are positive numbers, and the capital letter "M" is one of P, Si, Ge, B, Al, and GaIn), 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 (0≦x≦2)

[0029] 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(0≦x≦2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound containing one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0030] Or, sulfide-based solid electrolyte is Li 7-a MaPS 6-c X c Argyrodite-type compounds containing (0≦a≦2, (0≦c≦2)), where X can 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), or a combination thereof. The metal may be irradiated with at least one of tungsten (Tb), tungsten (Tc), tungsten (Td), tungsten (Te), tungsten (Tf), tungsten (Tg), tungsten (Tg), tungsten (Te), tungsten (Tg), tungsten (Te), tungsten (Tf), tungsten (Tg), tungsten (Te ...

[0031] 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 solid-state battery can be reduced and defects such as penetration and short circuit of the solid electrolyte membrane due to lithium dendrite formation can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0032] The solid electrolyte in the positive electrode active material layer 120 may have a smaller median particle size average particle diameter (D50) than the first and second solid electrolytes SE1 and SE2 in the solid electrolyte layer 300 described below. For example, the median particle size average particle diameter (D50) of the solid electrolyte contained 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 average particle diameter (D50) of the solid electrolyte contained in the solid electrolyte layer 300. Meanwhile, the median particle size average particle diameter (D50) may be a median diameter measured using a laser particle size distribution analyzer.

[0033] The positive electrode active material layer 120 may include a conductive material. The conductive material may be conductive without causing a chemical change in the all-solid-state battery 10 and may enhance 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.

[0034] The positive electrode active material layer 120 may further include a binder. The binder may bind together the positive electrode active material, solid electrolyte, conductive material, etc. in the positive electrode active material layer 120. The binder may include a material for improving the bonding strength between the positive electrode active material layer 120 and the positive electrode current collector 110. Examples of the binder include polyvinylidene fluoride, styrene-styrene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0035] The positive electrode active material layer 120 may contain 70 to 92 parts by weight of the positive electrode active material, based on 100 parts by weight of the total positive electrode active material, solid electrolyte, conductive material, and binder. The positive electrode active material layer 120 may contain 0.5 to 1.5 parts by weight of the binder, based on 100 parts by weight of the total positive electrode active material (PAM), solid electrolyte, conductive material, and binder.

[0036] The positive electrode active material layer 120 may include 1 to 50 parts by weight of the conductive material, based on 100 parts by weight of the solid electrolyte. If the conductive material is included in the positive electrode active material layer 120 in an amount 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 reducing 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 more than 50 parts by weight, based on 100 parts by weight of the solid electrolyte, the proportion of the conductive material may be too high, which may prevent the proper formation of a coating layer that covers the surface of the solid electrolyte.

[0037] The positive electrode active material layer 120 may further include additives such as a filler, a coating agent, a dispersant, an ion-conductive additive, etc., in addition to the above-described positive electrode active material, solid electrolyte, conductive material, and binder.

[0038] 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 disposed. The negative electrode current collector 210 may include, for example, a material that does not react with lithium, i.e., 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 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0039] The negative electrode current collector 210 may be made of one of the above-mentioned metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector 210 may have, for example, a plate or foil shape. Meanwhile, in one embodiment, the negative electrode current collector 210 may be omitted.

[0040] The anode coating layer 220 allows lithium metal to grow between the anode coating layer 220 and the anode current collector 210 when the all-solid-state battery 10 is charged. The anode coating layer 220 serves as a protective layer for the lithium metal and can also suppress the deposition and growth of lithium dendrites.

[0041] The anode coating layer 220 may include metal particles and a carbon-based material. For example, the anode coating layer 220 may include at least one metal particle 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 anode coating layer 220 may include at least one carbon-based material selected from the group consisting of carbon black, acetylene black, furnace black, ketzen black, and graphene. In one embodiment, the anode coating layer 220 may include a mixture of carbon black and silver (Ag).

[0042] The negative electrode coating layer 220 may further include other additives in addition to metal and carbon, such as at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion-conducting additive.

[0043] The anode coating layer 220 may have a smaller thickness than the cathode active material layer 120. The thickness of the anode 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 cathode active material layer 120. The thickness of the anode coating layer 220 may be, for example, 1 to 20 μm, 2 to 10 μm, or 3 to 7 μm. If the thickness of the anode coating layer 220 is excessively thin, lithium dendrites formed between the anode coating layer 220 and the anode current collector 210 may collapse the anode coating layer 220, thereby degrading the cycle characteristics of the all-solid-state battery 10. If the thickness of the anode coating layer 220 is excessively large, 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 anode coating layer 220 may increase, thereby degrading the cycle characteristics of the cell.

[0044] Meanwhile, although not shown, a carbon layer may be further included between the anode coating layer 220 and the solid electrolyte layer 300 to improve adhesion.

[0045] The solid electrolyte layer 300 may be provided between the positive electrode layer 100 and the negative electrode layer 200. The solid electrolyte layer 300 may include a sulfide-based solid electrolyte having excellent lithium ion conductivity. The solid electrolyte in the solid electrolyte layer 300 may be the same as or different from any one of the materials included in the solid electrolyte in the positive electrode active material layer 120 described above.

[0046] The solid electrolyte layer 300 may include a positive electrode solid electrolyte layer 310 and a negative electrode solid electrolyte layer 320. The positive electrode solid electrolyte layer 310 may be adjacent to the positive electrode layer 100, and the negative electrode solid electrolyte layer 320 may be adjacent to the negative electrode layer 200.

[0047] The positive electrode solid electrolyte layer 310 may include a first solid electrolyte SE1, and the negative electrode solid electrolyte layer 320 may include a second solid electrolyte SE2. Each of the first and second solid electrolytes SE1 and SE2 may have a particle shape such as a sphere or an ellipsoid.

[0048] Each of the first and second solid electrolytes SE1 and SE2 may include a sulfide-based solid electrolyte. The first and second solid electrolytes SE1 and SE2 may be the same or different. Each of the first and second solid electrolytes SE1 and SE2 may be amorphous, crystalline, or a mixture thereof. The solid electrolyte may include, for example, the sulfide-based solid electrolyte material described above, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements. For example, the solid electrolyte may be a material containing Li2S-P2S5. When the sulfide-based solid electrolyte material containing Li2S-P2S5 is used 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.

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

[0050] Or, sulfide-based solid electrolyte is Li 7-a MaPS 6-c X cArgyrodite-type compounds containing (0≦a≦2, (0≦c≦2)), where X can 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), or a combination thereof. The metal may be irradiated with at least one of tungsten (Tb), tungsten (Tc), tungsten (Td), tungsten (Te), tungsten (Tf), tungsten (Tg), tungsten (Tg), tungsten (Te), tungsten (Tg), tungsten (Te), tungsten (Tf), tungsten (Tg), tungsten (Te ...

[0051] 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 solid-state battery can be reduced and defects such as penetration and short-circuiting of the solid electrolyte membrane due to lithium dendrite formation can be prevented. The elastic modulus of the first solid electrolyte SE1 is, for example, 15 GPa to 35 GPa.

[0052] Each of the positive and negative electrode solid electrolyte layers 310, 320 may further include a binder. Examples of the binder included in the solid electrolyte layer 300 include, but are not limited to, styrene-styrene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc. The binders included in the positive and negative electrode solid electrolyte layers 310, 320 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.

[0053] In the embodiments of the present invention described below, detailed descriptions of technical features that overlap with those of the all-solid-state battery described above with reference to FIG. 1 will be omitted, and differences will be described in detail.

[0054] All-solid-state batteries containing sulfide-based solid electrolytes may generate hydrogen sulfide during charge and discharge, which may corrode the current collector and reduce the lifespan of the all-solid-state battery. In particular, hydrogen sulfide generated in the solid electrolyte layer may permeate the anode coating layer and corrode the anode current collector, significantly reducing the lifespan of the all-solid-state battery.

[0055] The composite substrate according to an embodiment of the present invention includes a nickel alloy layer, which provides excellent corrosion resistance against hydrogen sulfide. Therefore, an all-solid-state battery including the composite substrate has excellent life characteristics and cell performance.

[0056] FIG. 2 is a cross-sectional view illustrating an all-solid-state battery according to an embodiment.

[0057] 2, an all-solid-state battery 10 according to an embodiment may include an anode layer 200, a solid electrolyte layer 300 on the anode layer 200, and a cathode layer 100 on the solid electrolyte layer 300. The all-solid-state battery 10 according to an embodiment may include a composite substrate CPS. The composite substrate CPS may correspond to the anode current collector 210 of the all-solid-state battery 10 described above with reference to FIG. 1. Again, the anode layer 200 of the all-solid-state battery 10 may include the composite substrate CPS and an anode coating layer 220 on the composite substrate CPS.

[0058] FIG. 3 is a cross-sectional view illustrating an all-solid-state battery according to an embodiment.

[0059] Referring to FIG. 3 , an all-solid-state battery 10 according to an embodiment may include a cathode layer 100, a first solid electrolyte layer 3001 on an upper surface of the cathode layer 100, a first anode layer 2001 on an upper surface of the first solid electrolyte layer 3001, a second solid electrolyte layer 3002 on a lower surface of the cathode layer 100, and a second anode layer 2002 on a lower surface of the second solid electrolyte layer 3002.

[0060] The positive electrode layer 100 may include a positive electrode current collector 110, a first positive electrode active material layer 1201 on one surface of the positive electrode current collector 110, and a second positive electrode active material layer 1202 on the other surface of the positive electrode current collector 110. Each of the first positive electrode active material layer 1201 and the second positive electrode active material layer 1202 may correspond to the positive electrode active material layer 120 described with reference to FIG.

[0061] Each of the first negative electrode layer 2001 and the second negative electrode layer 2002 may correspond to the negative electrode layer 200 described with reference to Figure 1. As an example, the first negative electrode layer 2001 may include a first composite substrate CPS1 and a first negative electrode coating layer 2201. The second negative electrode layer 2002 may include a second composite substrate CPS2 and a second negative electrode coating layer 2202.

[0062] Each of the first solid electrolyte layer 3001 and the second solid electrolyte layer 3002 may correspond to the solid electrolyte layer 300 described with reference to Figure 1. As an example, the first solid electrolyte layer 3001 may include a first positive electrode solid electrolyte layer 3101 and a first negative electrode solid electrolyte layer 3201. The second solid electrolyte layer 3002 may include a second positive electrode solid electrolyte layer 3102 and a second negative electrode solid electrolyte layer 3202.

[0063] 4 and 5 are cross-sectional views illustrating a composite substrate CPS according to an embodiment of the present invention.

[0064] Referring to FIG. 4, the composite substrate CPS may include a polymer layer POL and a first nickel alloy layer NFL1 and a second nickel alloy layer NFL2 provided on both sides of the polymer layer POL, respectively.

[0065] The polymer layer POL may include a polymer film. For example, the polymer layer POL may include a polyethylene (PE) film, a polypropylene (PP) film, a polyvinylidene chloride (PVDC) film, a polyethylene terephthalate (PET) film, or a multilayer film that is a combination thereof. As an example, the polymer layer POL may be a polyethylene terephthalate (PET) film.

[0066] Each of the first and second nickel alloy layers NFL1 and NFL2 may contain a nickel alloy. Specifically, each of the first and second nickel alloy layers NFL1 and NFL2 may contain a nickel-iron (Ni-Fe) binary alloy. Because each of the first and second nickel alloy layers NFL1 and NFL2 contains a nickel-iron (Ni-Fe) binary alloy, it has low resistivity and excellent oxidation resistance.

[0067] Furthermore, nickel alloy layers containing nickel-iron (Ni-Fe) binary alloys are advantageous in terms of process efficiency. Specifically, when electroplating is performed using a plating solution containing nickel ions and iron ions, a nickel-iron (Ni-Fe) binary alloy film of uniform thickness can be formed. However, when chromium (Cr) or titanium (Ti) is used instead of iron (Fe), an oxide film forms, and further plating does not occur on the oxide film, making it difficult to form an alloy film of uniform thickness. Furthermore, because the oxide film is highly brittle, it easily detaches or cracks, making it difficult to maintain the shape of the current collector. As a result, additional processes must be performed to suppress or remove the oxide film, which can reduce process efficiency.

[0068] In one embodiment, the nickel content of each of the first and second nickel alloy layers NFL1 and NFL2 is 5 wt% to 70 wt%. Specifically, the nickel content of each of the first and second nickel alloy layers NFL1 and NFL2 may be 5 wt% to 50 wt%, 5 wt% to 40 wt%, 10 wt% to 50 wt%, 10 wt% to 30 wt%, 30 wt% to 50 wt%, or 65 wt% to 70 wt%. If the nickel content exceeds this range, thermal conductivity is low and generated heat cannot be effectively dissipated, which may result in reduced life characteristics. If the nickel content is below this range, resistivity may be high, which may result in reduced corrosion resistance to hydrogen sulfide.

[0069] In one embodiment, the nickel content of each of the first and second nickel alloy layers NFL1, NFL2 is 30 wt % to 95 wt %, and specifically, the nickel content of each of the first and second nickel alloy layers NFL1, NFL2 may be 50 wt % to 95 wt %, 60 wt % to 95 wt %, 50 wt % to 90 wt %, 70 wt % to 90 wt %, 50 wt % to 70 wt %, or 30 wt % to 35 wt %.

[0070] In one embodiment, the thickness of the polymer layer POL may be greater than the thickness of each of the first and second nickel alloy layers NFL1, NFL2.

[0071] In one embodiment, the thickness of each of the first and second nickel alloy layers NFL1 and NFL2 may be 0.5 μm to 5 μm, and the thickness of the polymer layer POL may be 4 μm to 25 μm.

[0072] The composite substrate CPS according to an embodiment of the present invention has excellent corrosion resistance against sulfurizing gases due to the inclusion of the first and second nickel alloy layers NFL1 and NFL2. That is, the composite substrate CPS according to an embodiment of the present invention has excellent sulfation resistance.

[0073] 5, the composite substrate CPS may further include a seed layer CSL. Specifically, the composite substrate CPS may further include a first seed layer CSL1 provided between the polymer layer POL and the first nickel alloy layer NFL1, and a second seed layer CSL2 provided between the polymer layer POL and the second nickel alloy layer NFL2.

[0074] The seed layer CSL can promote the formation of the nickel alloy layer NFL during electroplating by providing high electrical conductivity, and can also improve the strength of the composite substrate CPS by improving the adhesion between the polymer layer POL and the nickel alloy layer NFL.

[0075] Each of the first and second seed layers CSL1 and CSL2 may include copper, palladium, nickel, gold, chromium, or a combination thereof. As an example, each of the first and second seed layers CSL1 and CSL2 may be a copper thin film.

[0076] In one embodiment, the thickness of each of the first and second seed layers CSL1 and CSL2 may be 1 nm to 100 nm.

[0077] Hereinafter, a process for manufacturing a composite substrate according to an embodiment of the present invention will be described.

[0078] 6A is a flow chart illustrating a process for manufacturing a composite substrate according to an embodiment of the present invention, and FIGS. 6B to 6D are cross-sectional views illustrating a process for manufacturing a composite substrate according to an embodiment of the present invention.

[0079] Referring to FIG. 6, a method for manufacturing a composite substrate (S10) according to an embodiment of the present invention may include a pretreatment step (S100), a seed layer formation step (S200), and a nickel alloy layer formation step (S300).

[0080] In one embodiment, the pretreatment step (S100) may include activating the surface of the polymer film.

[0081] The polymer film may correspond to the polymer layer POL described above with reference to FIG.

[0082] The polymer film may be any of the polymer films described above with reference to Figure 4. For example, the polymer film may be a polyethylene (PE) film, a polypropylene (PP) film, a polyvinylidene chloride (PVDC) film, a polyethylene terephthalate (PET) film, or a multilayer film of a combination thereof.

[0083] In one embodiment, the polymer film can be stretched in the length direction. The polymer film can be wound up.

[0084] In one embodiment, the polymer film may have a thickness of 4 μm to 25 μm.

[0085] In one embodiment, activating the surface of a polymer film may involve removing impurities from the surface of a non-conductive polymer film and increasing the surface roughness. This increases the surface energy of the polymer film, thereby improving wettability and adhesion. The method for activating the surface of a polymer film is not particularly limited, and for example, chemical etching, plasma treatment, or ultraviolet / ozone treatment may be used to activate the surface of the polymer film.

[0086] In one embodiment, the pretreatment step (S100) may further include treating the polymer film with a catalyst. Specifically, by treating the surface of the surface-activated polymer film with a palladium catalyst, a seed layer can be efficiently formed thereafter. For example, the surface of the surface-activated polymer film may be passed through a first vessel containing a tin salt (SnCl2) solution, and then the surface of the polymer film may be passed through a second vessel containing a palladium salt (PdCl2) solution, thereby loading the palladium catalyst onto the surface of the polymer film. This may result in the surface of the polymer film being conductive.

[0087] 6A to 6C, the seed layer formation step (S200) may include forming a seed layer CSL on one or both surfaces of the polymer layer POL including the polymer film. For example, the seed layer formation step may include forming a first seed layer CSL1 on the upper surface of the polymer layer POL and forming a second seed layer CSL2 on the lower surface of the polymer layer POL.

[0088] The seed layer CSL may include copper, palladium, nickel, gold, chromium, or a combination thereof. For example, referring to Figures 6B and 6C, copper particles may be attached to the polymer layer POL to form the seed layer CSL, and the seed layer CSL may be a copper thin film.

[0089] When the nickel alloy layer NFL is formed directly on the polymer layer POL by electroplating, a large amount of Joule heating occurs due to the high resistivity of the polymer layer POL, which can cause the polymer layer POL to thermally decompose. Furthermore, if the strength of the applied current is reduced to prevent thermal decomposition, the plating speed decreases significantly, which can reduce process efficiency.

[0090] By forming a seed layer CSL on the polymer layer POL and then forming a nickel alloy layer NFL on the seed layer CSL, the intensity of the applied current can be increased, thereby improving the rate at which the nickel alloy layer NFL is formed, which in turn improves the production rate of the composite substrate CPS.

[0091] The method for forming the seed layer CSL is not particularly limited, and a plating method commonly used in the art may be used. For example, physical vapor deposition (PVD), chemical vapor deposition (CVD), or electroless plating may be used to form the seed layer CSL on the polymer layer POL.

[0092] In one embodiment, the palladium-catalyzed polymer layer POL may be supported in an electroless plating solution to form a seed layer CSL. For example, the electroless plating solution may include copper sulfate (CuSO4·5H2O) and a reducing agent. The reducing agent may include formaldehyde (HCHO), hydrazine (N2H4), sodium boride (NaBH4), or a combination thereof. The electroless plating solution may further include a complexing agent, a pH adjuster, a stabilizer, and the like.

[0093] In one embodiment, the seed layer CSL may have a thickness of 1 nm to 100 nm. For example, the first and second seed layers CSL1 and CSL2 may each have a thickness of 1 nm to 100 nm, specifically 10 nm to 50 nm.

[0094] 6A and 6D, the nickel alloy layer forming step (S300) may include electroplating a nickel alloy on the seed layer CSL to form a nickel alloy layer NFL. The nickel alloy may be a nickel-iron binary alloy. For example, forming the nickel alloy layer NFL may include forming a first nickel alloy layer NFL1 on the upper surface of the first seed layer CSL1 and forming a second nickel alloy layer NFL2 on the lower surface of the second seed layer CSL2.

[0095] Electroplating the nickel-iron alloy onto the seed layer CSL can be performed using a continuous electroplating method. Specifically, this can include running a composite substrate CPS including a polymer layer POL and a seed layer CSL on the polymer layer POL, and passing the target object through a plating vessel containing a plating solution PLS. The plating vessel can include a metal plate electrically connected to the positive electrode. The metal plate can be a nickel-iron alloy. A current can be applied to the target object while it is passing through the plating vessel. The target object can be electrically connected to the negative electrode.

[0096] In one embodiment, the plating solution PLS may include nickel chloride and iron sulfate.

[0097] In one embodiment, the pH of the plating solution PLS may be 2-5.

[0098] In one embodiment, the current density applied to the subject is 0.5 to 10 A / dm 2 , or 1 to 5 A / dm 2 It could be.

[0099] The nickel content in the formed nickel alloy layer NFL can be adjusted by adjusting the current density applied to the target object and the ratio of nickel ions to iron ions in the plating solution PLS. Specifically, the nickel ion content in the plating solution PLS can be increased, or the current density can be increased to increase the amount of reduced nickel. This allows for precise adjustment of the composition in the nickel alloy layer NFL.

[0100] In one embodiment, the nickel content in the nickel alloy layer NFL is 5 wt % to 70 wt %, and specifically, the ratio of nickel atoms in the nickel alloy layer NFL may be 5 wt % to 40 wt %, or 10 wt % to 30 wt %.

[0101] In one embodiment, the ratio of iron atoms in the nickel alloy layer NFL is 30 wt % to 95 wt %, and specifically, the ratio of iron atoms in the nickel alloy layer NFL may be 60 wt % to 95 wt %, or 70 wt % to 90 wt %.

[0102] In one embodiment, the content (wt%) of a specific element in the nickel alloy layer NFL may be measured and calculated by X-ray photoelectron spectroscopy (XPS) or energy dispersive X-ray spectroscopy.

[0103] The speed at which the target object passes through the plating vessel containing the plating solution, i.e., the traveling speed of the target object, can be appropriately adjusted. By adjusting the traveling speed of the target object, the thickness of the nickel alloy layer NFL formed on the seed layer CSL can be adjusted. In one embodiment, the thickness of the nickel alloy layer FNL can be 0.5 μm to 5 μm.

[0104] After the nickel alloy layer forming step (S300), a post-treatment step may be further performed, which may include washing the composite substrate CPS on which the nickel alloy layer NFL is formed, and winding up the composite substrate CPS.

[0105] The composite substrate CPS can be used as the anode current collector 210 described above with reference to FIG. 1, and an anode coating layer 220 can be formed on the composite substrate CPS to manufacture an anode 200 for an all-solid-state battery.

[0106] An all-solid-state battery can be manufactured by sequentially stacking the all-solid-state battery anode 200, the solid electrolyte layer 300, and the cathode layer 100. The solid electrolyte layer 300 may include the sulfide-based solid electrolyte described above.

[0107] Examples and comparative examples of the present invention will be described below. However, the examples described below are merely one embodiment of the present invention, and the present invention is not limited to the following embodiments.

[0108] Manufacturing example (composite base material) A rolled PET film with a thickness of 5 μm was prepared. The surface of the PET film was treated with tin chloride (SnCl2) and then catalyzed by placing it in a palladium salt (PdCl2) solution. The catalyzed PET film was then placed in an electroless plating solution containing copper sulfate to form thin copper films (seed layers) on both sides of the PET film. A first seed layer was formed with a uniform thickness on the top surface of the PET film, and a second seed layer was formed with a uniform thickness on the bottom surface of the PET film. The first and second seed layers were each formed with a thickness of approximately 20 nm.

[0109] The PET film with seed layers formed on both sides was immersed in a plating solution containing nickel chloride, iron sulfate, boric acid, sodium lauryl sulfate, saccharin, and sodium chloride, and connected to the negative electrode. A nickel-iron alloy metal plate was connected to the positive electrode and plating was performed. A first nickel alloy layer was formed with a uniform thickness on the top surface of the first seed layer. The first nickel alloy layer and the second nickel alloy layer were each formed with a thickness of approximately 1 μm.

[0110] The elemental compositions in the first and second nickel alloy layers were adjusted by adjusting the concentrations of nickel chloride and iron sulfate in the plating solution. Composite substrates having the following elemental compositions in the first and second nickel alloy layers were manufactured.

[0111] Preparation Example 1: Composite substrate containing approximately 70% by weight of Ni and approximately 30% by weight of Fe Preparation Example 2: Composite substrate containing approximately 50% by weight of Ni and approximately 50% by weight of Fe Preparation Example 3: Composite substrate containing approximately 30% by weight of Ni and approximately 70% by weight of Fe Preparation Example 4: Composite substrate containing about 10% by weight of Ni and about 90% by weight of Fe Preparation Example 5: Composite substrate containing about 3% by weight of Ni and about 97% by weight of Fe

[0112] Example 1 (negative electrode layer) Secondary particle carbon black (BET specific surface area: 150 m) composed of primary particles with an average particle size (D50) of 35 nm. 2 86 wt% of Ag (average particle size (D50): 400 nm), 5 wt% of Ag (average particle size: 60 nm), 3 wt% of carboxymethyl cellulose, and 6 wt% of styrene-styrene rubber were mixed with water to prepare a negative electrode coating layer slurry.

[0113] The negative electrode coating layer slurry was coated on the composite substrate prepared in Preparation Example 1 and dried to prepare a negative electrode for an all-solid-state battery.

[0114] (solid electrolyte layer) Solid electrolyte Li 5.75 PS 4.75 Cl 1.25 A mixture was prepared by adding an acrylic resin (A334, manufactured by Xeon) as a binder to the cellulose acylate (D50=3 μm) in a weight ratio of 98.5:1.5. A solvent, isobutyl isobutyrate (IBIB), was added to the mixture and stirred to prepare a composition for forming a solid electrolyte.

[0115] The composition for forming a solid electrolyte layer was placed on a polyethylene nonwoven fabric, and two blades with different gaps were moved, followed by drying in the air of a dry room at 25°C for 12 hours and vacuum drying at 70°C for 2 hours to form a sheet-type solid electrolyte formed on the polyethylene nonwoven fabric.

[0116] (positive electrode layer) LiNi 0.8 Co 0.1 Al 0.1 A positive electrode layer slurry was prepared by mixing 85.0 wt% of O2 positive electrode active material, 13.0 wt% of azirodite-type solid electrolyte Li6PS5Cl, 0.5 wt% of carbon nanotube conductive material, and 1.5 wt% of polyvinylidene fluoride binder in N-methylpyrrolidone solvent. The positive electrode layer slurry was coated on an aluminum current collector, and then dried and rolled at 60°C to prepare a positive electrode for an all-solid-state battery.

[0117] (all-solid-state half-cell) The prepared negative electrode, solid electrolyte, and lithium metal counter electrode were stacked in order, and a pressure of 2 Nm was applied to fabricate an all-solid-state half-cell battery (torque half-cell).

[0118] (All solid pull cell) The produced negative electrode, solid electrolyte, and positive electrode were stacked in this order, and subjected to isostatic pressing at 85°C and 500 MPa pressure for approximately 30 minutes to produce an all-solid-state secondary battery.

[0119] Example 2 When preparing an anode for an all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the composite substrate prepared in Preparation Example 2 was used.

[0120] Example 3 When preparing an anode for an all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the composite substrate prepared in Preparation Example 3 was used.

[0121] Example 4 When preparing an anode for an all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the composite substrate prepared in Preparation Example 4 was used.

[0122] Comparative Example 1 When preparing the anode for the all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the anode coating layer slurry was coated and dried on a copper foil having a thickness of 6.2 μm instead of the composite substrate.

[0123] Comparative Example 2 When preparing the anode for the all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the anode coating layer slurry was coated and dried on a nickel foil having a thickness of 6.2 μm instead of the composite substrate.

[0124] Comparative Example 3 When preparing an anode for an all-solid-state battery, an anode, a solid electrolyte layer, a cathode, an all-solid-state half-cell, and an all-solid-state pull cell were prepared in the same manner as in Example 1, except that the composite substrate of Preparation Example 5 was used.

[0125] That is, a composite substrate in which the nickel content of the nickel alloy layer is less than 5 wt % was used.

[0126] Table 1 shows the alloy layer compositions of the composite substrates according to the examples and comparative examples.

[0127] [Table 1]

[0128] Evaluation example 1: Cyclic voltage and current evaluation of metal substrate The cyclic voltammetry (CV) of the all-solid-state half-cells fabricated according to Comparative Examples 1 and 2 was measured in response to charge-discharge cycles.

[0129] The CV results of Comparative Example 1 after 1 to 6 charge-discharge cycles are shown in Figure 7A. Figure 7A (i) is a photograph of the copper foil (negative electrode current collector) before charge-discharge, and (ii) is a photograph of the copper foil (negative electrode current collector) after 6 charge-discharge cycles.

[0130] The CV results for Comparative Example 2 after 1 to 30 charge-discharge cycles are shown in Figure 7B. Figure 7B (i) is a photograph of the nickel foil (negative electrode current collector) before charge-discharge, and (ii) is a photograph of the nickel foil (negative electrode current collector) after 30 charge-discharge cycles.

[0131] 7A and 7B, the negative electrode current collector of Comparative Example 1 actively generated electrochemical side reactions during charging and discharging. Although the negative electrode current collector of Comparative Example 2 was partially discolored, no part was lost, and the side reaction current density was significantly reduced in the CV evaluation. This confirms that the nickel substrate has better sulfation resistance than the copper substrate.

[0132] Evaluation example 2: Cyclic voltage and current evaluation of composite substrate The cyclic voltammetry (CV) of the all-solid-state half-cells fabricated in Examples 1 to 4 and Comparative Examples 2 and 3 was measured in response to charge-discharge cycles.

[0133] The CV results of Comparative Example 2 after 1 to 7 charge-discharge cycles are shown in Figure 8A. The CV results of Comparative Example 3 and Examples 1 to 4 after 1 to 70 charge-discharge cycles are shown in Figures 8B to 8F, respectively.

[0134] 8A to 8F, it can be seen that the side reaction current density is high in the all-solid-state half-cells according to Comparative Examples 2 and 3, and therefore side reactions actively occur. In contrast, it can be seen from FIGS. 8C to 8F that the side reaction current density is significantly reduced in the all-solid-state half-cells according to Examples 1 to 4, and therefore side reactions are suppressed even after 70 or more charge-discharge cycles. In other words, it can be seen that the sulfation resistance of the composite substrates according to Examples 1 to 4 is remarkably excellent.

[0135] Evaluation example 3: Resistivity measurement of composite substrate The resistivity of the composite substrate was measured according to the composition of the nickel alloy layer. The negative electrodes prepared in Examples 1 to 4 were cut to a certain size (32 mm). The resistance of the cut negative electrodes was measured using an Agilent Technologies 4294A LCR meter and converted into resistivity values. The results are shown in Table 2 below.

[0136] [Table 2]

[0137] Referring to Table 2, it can be seen that the composite substrates according to Examples 1, 3, and 4 are relatively excellent in terms of resistivity.

[0138] Evaluation example 4: Initial discharge capacity and high-temperature life characteristics evaluation The all-solid-state pull cells prepared according to the examples and comparative examples were charged at 0.1 C, discharged at 0.1 C once, charged at 0.1 C and discharged at 0.33 C once, and charged at 0.1 C and discharged at 1 C once at 45° C. Then, the 0.33 C discharge capacity (initial discharge capacity) was measured after charging at 0.33 C. The results are shown in Table 3 below.

[0139] The all-solid-state pull cells prepared in the examples and comparative examples were charged and discharged 50 times at 45°C and 0.33C to determine the ratio of the 50th discharge capacity to the 1st discharge capacity. The results are shown in Table 3 below as capacity retention (%).

[0140] [Table 3]

[0141] Referring to Table 3, it can be seen that the all-solid-state pull cells prepared according to Comparative Examples 1 and 3 have excellent initial discharge capacities but low capacity retention. In the case of Comparative Example 1, it is determined that the life characteristics were significantly reduced due to corrosion of the copper current collector, and in the case of Comparative Example 3, it is determined that the nickel content was too low, resulting in insufficient antioxidant properties. It can also be seen that the all-solid-state pull cell prepared according to Comparative Example 2 had poor initial discharge capacity.

[0142] On the other hand, it was confirmed that the discharge capacity and capacity retention rate of the all-solid-state pull cells prepared in Examples 1 to 4 were excellent, and in particular, it was confirmed that the discharge capacity and capacity retention rate were remarkably excellent for the all-solid-state pull cells prepared in Examples 2 and 3. In the case of Example 1, it was determined that if the nickel content was too high, the thermal conductivity decreased, resulting in a slight decrease in life characteristics when repeated charge and discharge at high temperature. [Explanation of symbols]

[0143] 10 All-solid-state battery 100 Positive electrode layer 110 Positive electrode current collector 120 Cathode active material layer 200 negative electrode layer 210 Negative electrode current collector 220 Anode coating layer 300 solid electrolyte layer 310 Positive electrode solid electrolyte layer 320 Negative solid electrolyte layer CPS composite substrate POL polymer layer NFL1 First nickel alloy layer NFL2 Second nickel alloy layer CSL Seed Layer

Claims

1. a polymer layer; a first nickel alloy layer on a first surface of the polymer layer; a second nickel alloy layer on the second surface of the polymer layer; The composite substrate for an all-solid-state battery, wherein each of the first and second nickel alloy layers contains a nickel-iron binary alloy.

2. The composite substrate for an all-solid-state battery according to claim 1 , wherein a ratio of nickel atoms in the first nickel alloy layer is 5% by weight to 70% by weight.

3. The composite substrate for an all-solid-state battery according to claim 1 , wherein the first nickel alloy layer has a thickness of 0.5 μm to 5 μm.

4. The composite substrate for an all-solid-state battery according to claim 1 , further comprising a first seed layer provided between the polymer layer and the first nickel alloy layer.

5. The composite substrate for an all-solid-state battery according to claim 4 , wherein the first seed layer comprises copper, palladium, nickel, gold, chromium, or a combination thereof.

6. The composite substrate for an all-solid-state battery according to claim 4 , wherein the first seed layer has a thickness of 1 nm to 100 nm.

7. A composite substrate; a negative electrode coating layer on the composite substrate; The composite substrate is a polymer layer and a first nickel alloy layer on the polymer layer; The first nickel alloy layer comprises a nickel-iron binary alloy.

8. 8. The negative electrode for an all-solid-state battery according to claim 7, wherein the content of nickel in the first nickel alloy layer is 5% by weight to 70% by weight.

9. 8. The negative electrode for an all-solid-state battery according to claim 7, wherein the first nickel alloy layer has a thickness of 0.5 μm to 5 μm.

10. 8. The negative electrode for an all-solid-state battery according to claim 7, further comprising a first seed layer provided between the polymer layer and the first nickel alloy layer.

11. 11. The negative electrode for an all-solid-state battery according to claim 10, wherein the first seed layer comprises copper, palladium, nickel, gold, chromium, or a combination thereof.

12. The negative electrode for an all-solid-state battery according to claim 10 , wherein the first seed layer has a thickness of 1 nm to 100 nm.

13. The negative electrode coating layer is 8. The negative electrode for an all-solid-state battery according to claim 7, comprising: particles of 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); and a carbon-based material.

14. a negative electrode layer including a composite substrate and a negative electrode coating layer on the composite substrate; a solid electrolyte layer on the negative electrode layer; a positive electrode layer on the solid electrolyte layer, The composite substrate is a polymer layer and a first nickel alloy layer on the polymer layer; The all-solid-state battery, wherein the first nickel alloy layer comprises a nickel-iron binary alloy.

15. 15. The all-solid-state battery according to claim 14, wherein the content of nickel in the first nickel alloy layer is 5% by weight to 40% by weight.

16. 15. The all-solid-state battery of claim 14, wherein the first nickel alloy layer has a thickness of 0.5 μm to 5 μm.

17. 15. The all-solid-state battery of claim 14, further comprising a first seed layer provided between the polymer layer and the first nickel alloy layer.

18. 18. The all-solid-state battery of claim 17, wherein the first seed layer has a thickness of 1 nm to 100 nm.

19. The all-solid-state battery according to claim 14 , wherein the solid electrolyte layer includes a sulfide-based solid electrolyte.

20. The negative electrode coating layer is 15. The all-solid-state battery of claim 14, comprising at least one metal particle 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 a carbon-based material.

Images