Elastic sheet for all-solid-state rechargeable batteries, and all-solid-state rechargeable batteries

Abstract

The present invention relates to an elastic sheet for all-solid-state rechargeable batteries, and all-solid-state rechargeable batteries, the elastic sheet having an elastic modulus of 2.0 to 2.5 at a 40% compression rate, measured at 40°C to 60°C, and an elastic modulus of 24.0 to 30.0 at a 70% compression rate, measured at 40°C to 60°C.

Description

Elastic sheets for all-solid-state secondary batteries and all-solid-state secondary batteries

[0001] The present invention relates to an elastic sheet for an all-solid-state secondary battery and an all-solid-state secondary battery including the same.

[0002] Lithium secondary batteries, which offer high energy density and portability, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, active research is underway to utilize high-energy-density lithium secondary batteries as power sources for hybrid and electric vehicles, or as power storage devices.

[0003] Because lithium secondary batteries on the market use electrolytes containing flammable organic solvents, there is a safety issue that the batteries may explode or catch fire in the event of a collision or penetration.

[0004] Accordingly, all-solid-state secondary batteries, which utilize solid electrolytes instead of liquid electrolytes, are being proposed. All-solid-state secondary batteries are composed entirely of solid materials, offering safety advantages such as no risk of electrolyte leakage or explosion, and the ease of manufacturing thin batteries. Furthermore, a reduced anode thickness allows for improved high-speed charge / discharge performance, enabling high-voltage operation and high-energy density.

[0005] Provided are an elastic sheet for an all-solid-state secondary battery and an all-solid-state secondary battery capable of alleviating the shock transmitted during the pressurization process during the manufacture of an all-solid-state secondary battery and the stress generated by changes in the thickness of the battery during repeated charging and discharging, and improving the life characteristics.

[0006] In one embodiment, an elastic sheet for an all-solid-state secondary battery is provided, wherein the elasticity at a compression ratio of 40% measured at 40°C to 60°C is 2.0 to 2.5, and the elasticity at a compression ratio of 70% measured at 40°C to 60°C is 24.0 to 30.0.

[0007] In another embodiment, an all-solid-state secondary battery is provided, comprising two or more unit cells including a positive electrode; a negative electrode; and a solid electrolyte membrane positioned between the positive electrode and the negative electrode; and the above-described elastic sheet positioned between the unit cells and / or at the outermost portion of the unit cells.

[0008] According to one embodiment, an elastic sheet for an all-solid-state secondary battery and an all-solid-state secondary battery can be provided that can alleviate the shock transmitted during the pressurization process during the manufacture of an all-solid-state secondary battery and the stress generated by the change in the thickness of the battery during repeated charging and discharging, and can improve the life characteristics.

[0009] Figures 1 to 3 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0010] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0011] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on top of” another part, this includes not only cases where it is “directly on top of” the other part, but also cases where there is another part in between.

[0012] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0013] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0014] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size may be the average particle size (D ), which means the diameter of particles with a cumulative volume of 50% by volume in the particle size distribution. 50 ) means the average particle diameter (D 50 ) can be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope photograph or a scanning electron microscope photograph. Alternatively, a measuring device using dynamic light-scattering is used for measurement, and data analysis is performed to count the number of particles for each particle size range, and then the average particle diameter (D) is calculated from this. 50 ) value can be obtained. Or, it can be measured using the laser diffraction method. When measuring by the laser diffraction method, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of about 28 kHz at an output of 60 W, and then the average particle diameter (D) based on 50% of the particle size distribution in the measuring device is measured. 50 ) can be produced.

[0015] It should be understood that the terms "include," "comprising," or "having" herein are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0016] Also, here, “layer” includes not only the shape formed on the entire surface when observed in a plan view, but also the shape formed on a portion of the surface.

[0017] “Metal” is interpreted as a concept that includes common metals, transition metals, and metalloids (semi-metals).

[0018] Elastic sheets for all-solid-state secondary batteries

[0019] In one embodiment, an elastic sheet for an all-solid-state secondary battery is provided, wherein the elasticity at a compression ratio of 40% measured at 40°C to 60°C is 2.0 to 2.5, and the elasticity at a compression ratio of 70% measured at 40°C to 60°C is 24.0 to 30.0.

[0020] In all-solid-state secondary batteries, sulfide-based solid electrolytes with high ionic conductivity are mainly used. However, these sulfide-based solid electrolytes are easily deteriorated in air, so they need to be shielded from the atmosphere.

[0021] Accordingly, when manufacturing an all-solid-state secondary battery, an electrode assembly including a sulfide-based solid electrolyte is inserted into a case using a laminate film or a rigid material, sealed, and then pressurized to manufacture the battery.

[0022] However, during this pressurizing process, stress is transmitted to the solid electrolyte, causing it to break, or as charging and discharging progress, the thickness of the negative electrode changes, causing cracks to occur due to accumulated stress, resulting in a short circuit.

[0023] Additionally, if external pressure is not uniformly applied during battery discharge, the movement speed of lithium ions may slow down or they may migrate to locally pressurized areas, reducing discharge efficiency. Furthermore, uneven pressure can cause damage to the solid electrolyte.

[0024] Accordingly, technologies for applying elastic sheets to the exterior or interior of electrode assemblies are being developed. The elastic sheets, which can be referred to as buffer layers or elastic layers, can ensure even pressure transfer to the electrode assembly, thereby improving contact between solid components. Furthermore, the elastic sheets can alleviate stresses transmitted to solid electrolytes and other components, and can also suppress cracking in the solid electrolyte caused by stress accumulation due to changes in electrode thickness during charge and discharge.

[0025] As shown in Fig. 3, the elastic sheet (500) may be positioned between the unit cells and / or may be positioned on the outermost layer surface of the unit cell. Considering that the thickness of the negative electrode changes significantly during charge / discharge, particularly due to lithium deposition or dendrite formation, the elastic sheet (500) may be positioned on the outer side of the negative electrode, i.e., on the opposite side of the surface of the negative electrode where the solid electrolyte membrane is in contact, thereby buffering problems resulting from thickness changes. In addition, the elastic sheet (500) may be positioned on the outer side of the positive electrode and / or the negative electrode, thereby preventing deterioration by reaction with lithium.

[0026] Due to the nature of these elastic sheets using polymer resins, their properties change depending on temperature. Specifically, as the temperature decreases, the elastic sheets harden as they approach their glass transition temperature, rapidly changing their elastic modulus. On the other hand, as the temperature increases, they can rupture under pressure. Therefore, if the properties of the elastic sheets change rapidly with temperature, the internal environment of all-solid-state secondary batteries using these elastic sheets will also rapidly change, making them unsuitable for use in all-solid-state secondary batteries.

[0027] Accordingly, in one embodiment, an elastic sheet suitable for use in an all-solid-state secondary battery is provided by precisely controlling changes in compression ratio according to temperature of the elastic sheet so as to effectively perform the role of a buffer layer that can alleviate shock transmitted during the manufacture of an all-solid-state secondary battery and reduce stress transmitted according to changes in the thickness of an electrode.

[0028] To this end, the elastic sheet satisfies an elastic modulus of 2.0 to 2.5 at a compression ratio of 40% measured at 40°C to 60°C, and an elastic modulus of 24.0 to 30.0 at a compression ratio of 70% measured at 40°C to 60°C. An elastic sheet satisfying these properties can alleviate the impact transmitted during the pressurizing process during the manufacture of an all-solid-state secondary battery and the stress generated by changes in the thickness of the battery during repeated charge and discharge, thereby suppressing the occurrence of breakage due to temperature changes and improving the life characteristics of the battery.

[0029] For example, the elastic sheet may have an elastic modulus of 2.3 to 2.5 at a compression ratio of 40% measured at 40°C, and an elastic modulus of 26.5 to 30.0 at a compression ratio of 70% measured at 40°C. For example, the elastic sheet may have an elastic modulus of 2.0 to 2.3 at a compression ratio of 40% measured at 50°C, and an elastic modulus of 25.0 to 26.5 at a compression ratio of 70% measured at 50°C. For example, the elastic sheet may have an elastic modulus of 2.3 to 2.5 at a compression ratio of 40% measured at 60°C, and an elastic modulus of 24.0 to 25.0 at a compression ratio of 70% measured at 60°C. In the above ranges, the occurrence of breakage due to temperature change can be suppressed, and excellent life characteristics can be efficiently secured.

[0030] In one embodiment, the elastic sheet can satisfy the following Equation 1. When the following Equation 1 is satisfied, it exhibits a property behavior that can be suitably used depending on the internal environment of the all-solid-state secondary battery, and can effectively perform its role as a buffer layer of the all-solid-state secondary battery.

[0031] [Formula 1]

[0032] x×T / 7 ≤ y ≤ x×T / 3.3

[0033] (In the above equation 1, y represents the elastic modulus at a compression ratio of 70%, x represents the elastic modulus at a compression ratio of 40%, and T represents the measurement temperature.)

[0034] In Equation 1, the T may be 0°C to 80°C, for example, 10°C to 70°C, or 40°C to 60°C.

[0035] In one embodiment, the elastic sheet may include a polyurethane resin as a polymer resin, wherein the polyurethane resin refers to a homopolymer or copolymer having a urethane group. The glass transition temperature of the polyurethane resin may be -70°C to -38°C, for example, -60°C to -38°C, -55°C to -38°C, -53°C to -38°C, or -51°C to -38°C. In this way, by precisely controlling the glass transition temperature of the polyurethane resin, it has properties suitable for use in an all-solid-state secondary battery, and can effectively perform its role as a buffer layer of an all-solid-state secondary battery.

[0036] The polyurethane resin may be derived from a polyether polyol. The polyether polyol may have a functional group number of 2 to 4 and a number average molecular weight of 10,000 to 5,000,000. In addition to the polyether polyol, the polyurethane resin may also use a polyester polyol, a polycarbonate polyol, or a combination thereof. Examples of the polyester polyol include those obtained by condensation of low molecular weight polyols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, hexanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, diglycerin, sorbitol, and sucrose with succinic acid, adipic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, succinic anhydride, maleic anhydride, and phthalic anhydride. In addition, examples of polyester polyols include polyols that are ring-opening condensates of caprolactone and methylvalerolactone, which are classified as lactone esters. Examples of polycarbonate polyols include those obtained by dealcoholization reactions of polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol with dialkyl carbonates, dialkylene carbonates, and diphenyl carbonates. The polycarbonate polyol may have a functional group number of 2 to 3 and a number average molecular weight of 500 to 1000 (or a hydroxyl value of 112 mgKOH / g to 224 mgKOH / g).

[0037] The above elastic sheet may further comprise hollow particles in addition to the polyurethane resin, which is a polymer resin. The hollow particles are particles with an internal void, and may be expressed as hollow spheres or hollow beads, and may be hollow nanoparticles or hollow microparticles. When the above elastic sheet comprises hollow particles, the sheet can increase compressive strength while maintaining an appropriate density, and can exhibit a foam shape.

[0038] The hollow particles may be included in an amount of 1 to 8 parts by weight based on 100 parts by weight of the polyurethane resin, for example, 1 to 7 parts by weight, or 2 to 6 parts by weight. When the hollow particles are included in this content range, it is advantageous for producing an elastic sheet in a foam form, and the compressive strength, stress relaxation ability, and resilience of the elastic sheet can be improved.

[0039] The hollow particles may be inorganic hollow particles, organic hollow particles, or a combination thereof. That is, the hollow particles may be composed of an inorganic material or an organic material such as a polymer.

[0040] The inorganic hollow particles may include, for example, glass, metal oxide, metal carbide, metal fluoride, or a combination thereof. Specifically, the inorganic hollow particles may be formed of glass, silicon oxide, nickel oxide, barium oxide, platinum oxide, zinc oxide, aluminum oxide, zirconium oxide, iron oxide, titanium oxide, calcium carbonate, magnesium fluoride, or a combination thereof, and as an example, the inorganic hollow particles may be glass bubbles.

[0041] The organic hollow particles may include, for example, an acrylic resin, a vinyl chloride resin, a urea resin, a phenol resin, a rubber, or a combination thereof. In addition, the organic hollow particles may be expandable or non-expandable, and the expandable organic hollow particles may be, for example, expandable at 120°C to 150°C.

[0042] The size of the above hollow particles (D 50) may be, for example, a micro size, and specifically, may be 2 ㎛ to 100 ㎛, 5 ㎛ to 90 ㎛, 10 ㎛ to 80 ㎛, or 20 ㎛ to 70 ㎛. Hollow particles having such a size are advantageous for making an elastic sheet in a foam form, and can lower the density and improve stress relaxation and resilience while improving the compressive strength of the elastic sheet. Here, the size of the hollow particles can be expressed as an average particle diameter or a median particle diameter, and is the diameter (D) of particles having a cumulative volume of 50 vol% in the particle size distribution as measured by a particle size analyzer. 50 ) can mean.

[0043] The above elastic sheet may further include elastic particles in addition to the polyurethane resin, which is a polymer resin. The elastic particles may be particles made of a polymer having elasticity, such as rubber. The elastic particles can increase the restoring force while maintaining the stress relaxation capacity of the polymer resin.

[0044] The elastic particles may be included in an amount of 0.1 to 5 parts by weight, for example, 0.5 to 4 parts by weight, or 1 to 3 parts by weight, based on 100 parts by weight of the polyurethane resin. When the elastic particles are included in this content range, the compressive strength, stress relaxation strength, and resilience can be maximized without lowering the density and adhesiveness of the polymer resin.

[0045] The elastic particles may comprise, for example, a polymer derived from natural rubber, alkyl acrylate, olefin, butadiene, isoprene, styrene, acrylonitrile, copolymers thereof, or a combination thereof. The elastic particles may have, for example, a glass transition temperature of -70°C to 0°C.

[0046] The alkyl acrylate may be a C1 to C20 alkyl acrylate, and may include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylpentyl (meth)acrylate, 2-ethylheptyl (meth)acrylate, 2-ethylnonyl (meth)acrylate, 2-propylhexyl (meth)acrylate, 2-propyloctyl (meth)acrylate, or a combination thereof.

[0047] The elastic particles may include, for example, polyalkyl acrylate, ethylene-propylene-diene rubber, butadiene rubber, isoprene rubber, styrene-butadiene rubber, styrene-isoprene rubber, acrylonitrile-butadiene rubber, or combinations thereof.

[0048] The elastic particles may have, for example, a core-shell structure, in which case it is advantageous to exhibit an appropriate size and elasticity. The core and shell may each include, for example, a polyalkyl acrylate, and in one embodiment, the core and shell may include different polyalkyl acrylates, for example, the core may include polybutyl (meth)acrylate, and the shell may include polymethyl (meth)acrylate. In this case, the dispersibility within the elastic sheet composition is excellent, and the compressive strength, stress relaxation strength, and resilience of the elastic sheet can be improved.

[0049] The above elastic particles may be, for example, nano-sized. Specifically, the size (D) of the elastic particles 50) may be 10 nm to 900 nm, for example, 10 nm to 700 nm, 50 nm to 500 nm, or 100 nm to 400 nm. Elastic particles satisfying these sizes have excellent dispersibility in the elastic sheet composition and can increase the restoring force while maintaining the stress relaxation ability of the elastic sheet. Here, the size of the elastic particles can be expressed as an average particle diameter or a median particle diameter, and is the diameter (D) of particles having a cumulative volume of 50% by volume in the particle size distribution as measured by a particle size analyzer. 50 ) can mean.

[0050] For example, the elastic particles may have a core-shell structure, and the size of the core (e.g., average particle diameter) may be from 8 nm to 850 nm, for example, from 8 nm to 650 nm, from 40 nm to 480 nm, or from 100 nm to 300 nm. In addition, the average size of the shell may be from 5 nm to 100 nm, for example, from 10 nm to 50 nm, or from 10 nm to 25 nm. In this range, the elastic sheet can effectively function as a buffer layer of an all-solid-state secondary battery.

[0051] The above elastic sheet may further include inorganic particles. In this case, the modulus and compressive strength of the elastic sheet can be improved while simultaneously improving the recovery rate.

[0052] The inorganic particles may include, for example, alumina, titania, boehmite, barium sulfate, calcium carbonate, calcium phosphate, amorphous silica, mesoporous silica, fumed silica, crystalline glass particles, kaolin, talc, silica-alumina composite oxide particles, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, mica, magnesium oxide, or combinations thereof.

[0053] The inorganic particles may be included, for example, in an amount of 0.001 to 50 parts by weight, for example, 0.01 to 45 parts by weight, or 0.1 to 40 parts by weight, based on 100 parts by weight of the polyurethane resin. In this case, the compressive strength, stress relaxation rate, and recovery rate of the elastic sheet can be improved without deteriorating the properties of the polyurethane resin.

[0054] The average particle diameter of the above-mentioned inorganic particles may be 0.1 ㎛ to 2 ㎛, for example, 0.1 ㎛ to 1.5 ㎛, or 0.2 ㎛ to 1.0 ㎛. The above-mentioned average particle diameter is measured using a laser scattering particle size distribution meter, and is the median particle diameter (D) when 50% is accumulated from the small particle side in volume conversion. 50 ) may mean.

[0055] In addition to the aforementioned components, the elastic sheet may further include suitable additives, such as an initiator, a crosslinking agent, a coupling agent, a foaming agent, or a combination thereof. Furthermore, in order to produce a foam-shaped elastic sheet, the elastic sheet may further include an inert gas such as nitrogen or argon, in addition to or together with the foaming agent.

[0056] Each additive may be included in an appropriate amount according to the purpose, and for example, may be included in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the polyurethane resin, for example, may be included in an amount of 0.001 to 5 parts by weight, 0.01 to 5 parts by weight, or 0.01 to 3 parts by weight.

[0057] In one embodiment, the average thickness of the elastic sheet may be 100 μm to 10 mm, for example, 100 μm to 900 μm, 100 μm to 800 μm, or 200 μm to 700 μm. For example, the elastic sheet may have a different thickness depending on the location, for example, the thickness of the elastic sheet positioned between unit cells may be 100 μm to 300 μm, and the thickness of the elastic sheet positioned at the outermost edge of the unit cell may be 700 μm to 1 mm. The physical properties of the elastic sheet described above may be measured in a state where the thickness of the elastic sheet is adjusted within a range of 100 μm to 10 mm (for example, 400 μm).

[0058] All-solid-state secondary battery

[0059] In one embodiment, an all-solid-state secondary battery is provided, which includes two or more unit cells including a positive electrode; a negative electrode; and a solid electrolyte membrane positioned between the positive electrode and the negative electrode; and the above-described elastic sheet positioned between the unit cells and / or at the outermost portion of the unit cells. That is, the elastic sheet may be positioned at least one of between the unit cells and at the outermost portion of the unit cells. Since the all-solid-state secondary battery includes the above-described elastic sheet, it can secure excellent charge / discharge efficiency and lifespan characteristics.

[0060] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an embodiment. Referring to FIG. 1, the all-solid-state secondary battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode current collector (401) and a negative electrode active material layer (403); a solid electrolyte membrane (300); and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode current collector (201) are laminated is housed in a battery case. The all-solid-state secondary battery (100) may further include an elastic sheet (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 1 illustrates one unit cell including a cathode (400), a solid electrolyte membrane (300), and an anode (200), as illustrated in FIG. 3, two unit cells may be stacked to manufacture an all-solid-state secondary battery, or two or more unit cells may be stacked, for example, 2 to 100, 3 to 50, 4 to 20, etc., to manufacture an all-solid-state secondary battery. In addition, the unit cell may include one or more cathodes, and similarly, may include one or more solid electrolyte membranes and one or more anodes. For example, the unit cell may be a monocell having a cathode / solid electrolyte membrane / cathode structure, or a bicell having a cathode / solid electrolyte membrane / anode / solid electrolyte membrane / cathode structure.

[0061] anode

[0062] In one embodiment, the device comprises a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer comprises a positive electrode active material and may further comprise a binder and / or a conductive material. Alternatively, the positive electrode active material layer may further comprise a solid electrolyte.

[0063] positive electrode active material

[0064] The above positive electrode active material can be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the positive electrode active material may use a compound capable of reversible intercalation and deintercalation of lithium, may include a lithium transition metal composite oxide, and may include a compound represented by any one of the following chemical formulas. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G bO4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0065] The positive electrode active material may include, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), lithium iron phosphate oxide (LFP), or a combination thereof.

[0066] The positive electrode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 1, a lithium cobalt-based oxide represented by the following chemical formula 2, a lithium iron phosphate-based compound represented by the following chemical formula 3, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 4, or a combination thereof.

[0067] [Chemical Formula 1]

[0068] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0069] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0070] In the above chemical formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0071] [Chemical Formula 2]

[0072] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0073] In the above chemical formula 2, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0074] [Chemical Formula 3]

[0075] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0076] In the above chemical formula 3, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0077] [Chemical Formula 4]

[0078] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0079] In the above chemical formula 4, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0080] The above positive electrode active material may be in the form of particles, and the average particle diameter (D) of the positive electrode active material 50 ) may be 1 ㎛ to 25 ㎛, for example, 3 ㎛ to 25 ㎛, 1 ㎛ to 20 ㎛, 1 ㎛ to 18 ㎛, 3 ㎛ to 15 ㎛, or 5 ㎛ to 15 ㎛. For example, the positive electrode active material may be a small particle having an average particle diameter (D50) of 1 ㎛ to 9 ㎛ and an average particle diameter (D 50 ) may include particles having a particle size range of 10 ㎛ to 25 ㎛. The positive electrode active material having such a particle size range can be harmoniously mixed with other components in the positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle size is obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle sizes (diameter, or major axis, or major axis length), and then obtaining a particle size distribution, and in the particle size distribution, the diameter (D) of the particles having a cumulative volume of 50% by volume 50 ) may be taken as the average particle diameter.

[0081] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0082] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be, for example, Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, Zr, or a combination thereof. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles by facilitating the movement of lithium ions and electron conduction, thereby improving the performance of the positive electrode active material.

[0083] The positive electrode active material may be included in an amount of 55 wt% to 99 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 95 wt%, or 75 wt% to 91 wt%.

[0084] solid electrolyte

[0085] The solid electrolyte included in the positive electrode active material layer may be selected from, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. In particular, the solid electrolyte included in the positive electrode active material may be a sulfide-based solid electrolyte. The description given below with respect to the solid electrolyte membrane may be equally applied to the solid electrolyte included in the positive electrode active material layer.

[0086] With respect to 100 wt% of the above positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0087] In addition, in the positive electrode active material layer, 65 wt% to 99 wt% of the positive electrode active material and 1 wt% to 35 wt% of the solid electrolyte may be included based on the total weight of the positive electrode active material and the solid electrolyte, for example, 80 wt% to 90 wt% of the positive electrode active material and 10 wt% to 20 wt% of the solid electrolyte may be included. When the solid electrolyte is included in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0088] bookbinder

[0089] The above binder serves to adhere positive electrode active material particles well to each other and also to adhere positive electrode active material well to a current collector, and representative examples thereof include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0090] The content of the binder in the positive electrode active material layer may be approximately 0.1 wt% to 5 wt% with respect to 100 wt% of the positive electrode active material layer.

[0091] Challenge

[0092] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to provide conductivity to the electrode, and any material that does not cause a chemical change and is electronically conductive in the battery to be formed may be used. Examples of conductive materials that may be used include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0093] The content of the conductive material in the positive electrode active material layer may be 0 wt% to 3 wt%, 0.01 wt% to 2 wt%, or 0.1 wt% to 1 wt% with respect to 100 wt% of the positive electrode active material layer.

[0094] Aluminum foil may be used as the positive electrode current collector, but is not limited thereto.

[0095] cathode

[0096] According to one embodiment, an anode for an all-solid-state secondary battery includes a cathode current collector and a cathode active material layer positioned on the cathode current collector. The cathode active material layer includes a cathode active material and may further include a binder and / or a conductive material. Alternatively, the cathode active material layer may optionally further include the aforementioned solid electrolyte.

[0097] The above negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0098] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0099] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, Sn or a combination thereof can be used.

[0100] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used, and the Si-based negative electrode active material may be silicon, a silicon-carbon composite, or SiO. x(0 <x≤2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 또는 이들의 조합에서 선택되는 원소이며, Si은 아님), 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소 또는 이들의 조합에서 선택되는 원소이며, Sn은 아님) 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 또는 이들의 조합에서 선택되는 것을 사용할 수 있다.

[0101] For example, the negative active material may include silicon-carbon composite particles. The average particle diameter (D) of the silicon-carbon composite particles 50 ) may be, for example, 0.5 ㎛ to 20 ㎛. The average particle diameter (D 50 ) is measured by a particle size analyzer and means the diameter of particles having a cumulative volume of 50% by volume in the particle size distribution. With respect to 100 wt% of the silicon-carbon composite particles, silicon may be included in an amount of 10 wt% to 60 wt% and carbon may be included in an amount of 40 wt% to 90 wt%. The silicon-carbon composite particles may include, for example, a core including silicon particles, and a carbon coating layer located on the surface of the core. The average particle diameter (D) of the silicon particles in the core 50) may be 10 nm to 1 ㎛, or 10 nm to 200 nm. The silicon particles may exist as silicon alone, in the form of a silicon alloy, or in an oxidized form. The oxidized form of silicon is SiO x (0 <x≤2)로 표시될 수 있다. 또한, 상기 탄소 코팅층의 두께는 약 5 ㎚ 내지 100 ㎚일 수 있다.

[0102] For example, the silicon-carbon composite particle may include a core including silicon particles and crystalline carbon, and a carbon coating layer located on the surface of the core and including amorphous carbon. For example, in the silicon-carbon composite particle, the amorphous carbon may not be present in the core but may be present only in the carbon coating layer. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof, and the amorphous carbon may be formed from coal pitch, mesophase pitch, petroleum pitch, coal oil, petroleum heavy oil, or a polymer resin (phenol resin, furan resin, polyimide resin, etc.). At this time, the content of the crystalline carbon may be 10 wt% to 70 wt%, and the content of the amorphous carbon may be 20 wt% to 40 wt% with respect to 100 wt% of the silicon-carbon composite particle.

[0103] In the above silicon-carbon composite particle, the core may include a void in the central portion. The radius of the void may be 30% to 50% of the radius of the silicon-carbon composite particle.

[0104] The silicon-carbon composite particles described above can effectively suppress problems such as volume expansion, structural collapse, or particle crushing due to charge and discharge, thereby preventing the phenomenon of conductive path disconnection, realizing high capacity and high efficiency, and are advantageous for use under high voltage or fast charging conditions.

[0105] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in combination with a carbon-based negative electrode active material. When the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material are used in combination, the mixing ratio can be 1:99 to 90:10 by weight.

[0106] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0107] In one embodiment, the negative electrode active material layer further includes a binder and may optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0108] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0109] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0110] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0111] When using an aqueous binder as the above-mentioned negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li.

[0112] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials including copper, nickel, aluminum, and silver in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0113] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0114] precipitation cathode

[0115] As another example, the negative electrode for an all-solid-state secondary battery may be a precipitation-type negative electrode. The precipitation-type negative electrode may refer to a negative electrode that does not contain a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, thereby acting as a negative electrode active material.

[0116] Fig. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode. Referring to Fig. 2, the precipitation-type negative electrode (400') may include a negative electrode current collector (401) and a negative electrode coating layer (405) positioned on the negative electrode current collector. The all-solid-state secondary battery including the precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present. Subsequently, during charging, high-density lithium metal is precipitated or deposited between the negative electrode current collector (401) and the negative electrode coating layer (405), or on the negative electrode coating layer (405), to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state secondary battery that has been charged more than once, a precipitation-type negative electrode (400') may include, for example, a negative electrode current collector (401), a lithium metal layer (404) positioned on the negative electrode current collector, and a negative electrode coating layer (405) positioned on the lithium metal layer. The lithium metal layer (404) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium deposition layer, or a negative electrode active material layer.

[0117] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a lithium-philic metal, a carbon material, or a combination thereof.

[0118] The above lithium-philic metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type of these or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D50 ) may be less than about 4 μm, for example, 10 nm to 4 μm.

[0119] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0120] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary battery can be improved. The negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0121] The above-described cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal may be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0122] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0123] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 μm, or 500 nm to 10 μm, or 1 μm to 5 μm.

[0124] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the negative current collector, that is, between the negative current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state secondary battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0125] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0126] The thickness of the lithium metal layer (404) may be 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, or 1 µm to 50 µm. Within the above range, the lithium storage layer can sufficiently perform its role and prevent performance degradation due to an increase in battery volume.

[0127] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0128] solid electrolyte membrane

[0129] In an all-solid-state secondary battery according to one embodiment, the solid electrolyte membrane (300) includes a solid electrolyte, and the solid electrolyte may include, for example, a solid electrolyte selected from among a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof.

[0130] Sulfide-based solid electrolyte

[0131] For example, the solid electrolyte membrane (300) may include a sulfide-based solid electrolyte having excellent ion conductivity. The sulfide-based solid electrolyte may include, for example, Li2S-P2S5, Li2S-P2S5-LiX (wherein X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0132] Such sulfide-based solid electrolytes can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0133] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0134] According to one embodiment, a sulfide-based solid electrolyte can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0135] For example, the sulfide-based solid electrolyte may be in the form of particles and may include argyrodite-type sulfides. These argyrodite-type sulfide-based solid electrolyte particles have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It possesses high ionic conductivity approaching the S / cm range. Furthermore, it can form a close bond between the positive electrode active material and the solid electrolyte without causing a decrease in ionic conductivity, and can form a close interface between the electrode and the solid electrolyte membrane. An all-solid-state secondary battery including this can exhibit improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0136] The above sulfide-based solid electrolyte may include, for example, an argyrodite-type sulfide represented by the chemical formula 11 below.

[0137] [Chemical Formula 11]

[0138] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0139] In the above chemical formula 11, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0140] For example, in chemical formula 11, a halogen element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 11에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 11에서 M 3 can be understood as an element substituted in the P position, and 0 <e<1일 수 있다. 화학식 11에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며, S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0141] For example, in chemical formula 11, a+b+c+h=7, d+e=1, and f+g+h=6.

[0142] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0143] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, and optionally, lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0144] Average particle diameter (D) of sulfide-based solid electrolyte particles 50 ) may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, may be small particles of 0.1 ㎛ to 1.9 ㎛, or may be large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle diameter of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle diameter of 2.0 ㎛ to 5.0 ㎛. The average particle diameter of the sulfide-based solid electrolyte particles may be measured by an electron microscope image, and for example, a particle size distribution is obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, where D50 It may have been calculated.

[0145] For example, the sulfide-based solid electrolyte may be included in an amount of 80 wt% to 97 wt% based on 100 wt% of the solid electrolyte membrane, for example, 85 wt% to 97 wt%, 90 wt% to 97 wt%, 93 wt% to 97 wt%, or 94 wt% to 96 wt%. Within this range, excellent ionic conductivity can be secured while ensuring the durability of the battery.

[0146] Oxide-based solid electrolyte

[0147] The solid electrolyte membrane (300) may include an oxide-based solid electrolyte. The oxide-based solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x Lay TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0148] Halide-based solid electrolyte

[0149] The solid electrolyte membrane (300) may include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halogen element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0150] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li a M1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte may be, for example, Li2ZrCl6, Li 2.7 Y0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0151] bookbinder

[0152] A solid electrolyte membrane according to one embodiment may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0153] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte membrane, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte membrane can be well bound without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0154] Other ingredients

[0155] The solid electrolyte membrane may optionally further include other components such as alkali metal salts, and / or ionic liquids, and / or conductive polymers.

[0156] The alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte membrane may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte membrane.

[0157] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0158] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0159] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0160] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0161] The ionic liquid may include, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, or a combination thereof.

[0162] In the above solid electrolyte membrane, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte membrane satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0163] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0164] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0165] Example 1

[0166] 1. Manufacturing of elastic sheets

[0167] An organic nanoparticle having an average particle diameter of 200 nm is prepared as a core-shell particle composed of 70 wt% of a polybutylacrylate core and 30 wt% of a polymethylmethacrylate shell, manufactured by an emulsion polymerization method as an elastic particle. At this time, the average particle diameter of the core was 150 nm, and the average thickness of the shell was 25 nm.

[0168] 100 parts by weight of polyurethane resin (manufacturer: ICH, model name: M4-2, glass transition temperature (Tg): -38 ℃), 2.5 parts by weight of the elastic particles, and 0.01 part by weight of an initiator (Irgacure651) were mixed in a reactor to obtain a viscous liquid. 0.3 parts by weight of the initiator (Irgacure651), 0.1 part by weight of hexanediol diacrylate as a crosslinking agent, and hollow particles (glass bubbles; 3M) were added to the viscous liquid. TM An elastic sheet composition having adhesiveness was prepared by mixing 5 parts by weight of K1 (median particle size 65 ㎛) and 0.1 part by weight of fumed silica (AEROSIL 200).

[0169] The above elastic sheet composition is applied between PET films, which are release films, and exposed to ultraviolet light at 2000 mJ / cm 2 By investigating the amount of light, an elastic sheet bonded onto a PET film was manufactured. The thickness of the manufactured elastic sheet was 300 ㎛.

[0170] 2. Manufacturing of the anode

[0171] LiNi 0.8 Co 0.15 Mn 0.05A positive electrode composition was prepared by mixing 85 wt% of an O2 positive electrode active material, 13.5 wt% of a lithium argyrodite-type solid electrolyte Li6PS5Cl, 1.0 wt% of a polyvinylidene fluoride binder, and 0.5 wt% of a carbon nanotube conductive material. The prepared positive electrode composition was coated on a positive electrode current collector using a bar coater, and dried and rolled to prepare a positive electrode.

[0172] 3. Manufacturing of solid electrolyte membranes

[0173] An argyrodite-type solid electrolyte Li6PS5Cl(D) was added to a binder solution in which an acrylic binder (SX-A334, Zeon) was dissolved in an isobutyryl isobutyrate (IBIB) solvent. 50 =3㎛) was added and stirred to prepare a slurry. The slurry contains 98.5 wt% of solid electrolyte and 1.5 wt% of binder. The slurry was applied onto a release PET film using a bar coater and dried at room temperature to prepare a solid electrolyte membrane.

[0174] 4. Manufacturing of the cathode

[0175] Primary entry (D 50 ) carbon black with an average particle diameter (D) of about 30 nm 50 ) was prepared by mixing silver (Ag) of about 60 nm in a weight ratio of 3:1, and 0.25 g of the above complex was added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder and mixed to prepare a negative electrode coating layer composition. This was applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type negative electrode in which a negative electrode coating layer was formed on the current collector.

[0176] 5. Manufacturing of all-solid-state batteries

[0177] A unit stack cell is manufactured by stacking in the order of cathode / solid electrolyte membrane / anode / solid electrolyte membrane / cathode. An elastic sheet is interposed between two unit stack cells and on the outermost layer to manufacture a battery structure.

[0178] The thus-laminated structure was placed in an aluminum pouch laminate film and subjected to warm isostatic pressing (WIP; WIP) at 80°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery. The aluminum pouch was unpacked to manufacture a battery structure laminated in the following order: elastic sheet / negative electrode / solid electrolyte membrane / positive electrode / solid electrolyte membrane / negative electrode / elastic sheet / negative electrode / solid electrolyte membrane / positive electrode / solid electrolyte membrane / negative electrode / elastic sheet.

[0179] In a pressurized state, the thickness of the positive electrode active material layer is about 100 μm, the thickness of the negative electrode coating layer is about 7 μm, the thickness of the solid electrolyte membrane is about 60 μm, and the thickness of the elastic sheet is about 180 μm.

[0180] Example 2

[0181] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M4-4, glass transition temperature (Tg): -43 ℃) was used in the manufacture of the elastic sheet.

[0182] Example 3

[0183] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M3-2, glass transition temperature (Tg): -51 ℃) was used in the manufacture of the elastic sheet.

[0184] Example 4

[0185] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M3-3, glass transition temperature (Tg): -47 ℃) was used in the manufacture of the elastic sheet.

[0186] Comparative Example 1

[0187] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M4-1, glass transition temperature (Tg): -28 ℃) was used in the manufacture of the elastic sheet.

[0188] Comparative Example 2

[0189] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M4-3, glass transition temperature (Tg): -37 ℃) was used in the manufacture of the elastic sheet.

[0190] Comparative Example 3

[0191] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M3-1, glass transition temperature (Tg): -23 ℃) was used in the manufacture of the elastic sheet.

[0192] Comparative Example 4

[0193] An elastic sheet and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a polyurethane resin (manufacturer: ICH, model name: M5, glass transition temperature (Tg): -37 ℃) was used in the manufacture of the elastic sheet.

[0194] Evaluation Example 1: Elasticity Evaluation

[0195] Using the elastic sheets manufactured in Examples 1 to 4 and Comparative Examples 1 to 4 described above, the elastic moduli at 40% and 70% compression ratios measured at 40°C to 60°C were measured using a compression elastic modulus tester, and the results are shown in Table 1 below. Here, the compression ratio was calculated using the following formula A, and the elastic modulus was calculated using the following formula B.

[0196] [Formula A]

[0197] Compression ratio (Strain, %) = Change in length after compression / Initial length × 100

[0198] [Formula B]

[0199] Modulus of elasticity (MPa) = axial force per unit surface area / compressibility

[0200] Measurement temperature (℃) Elastic modulus at 40% compression ratio (MPa) Elastic modulus at 70% compression ratio (MPa) Example 1 402.5 29.5 Example 2 402.3 24.0 Example 3 402.23 0.0 Example 4 402.0 26.0 Comparative example 1 403.7 25.3 Comparative example 2 501.5 26.0 Comparative example 3 402.22 0.2 Comparative example 4 602.4 3 5.8

[0201] Referring to Table 1 above, it can be confirmed that the elastic sheets manufactured in Examples 1 to 4 have an elastic modulus at a compression ratio of 40% measured at 40°C to 60°C that satisfies the range of 2.0 to 2.5, and an elastic modulus at a compression ratio of 70% measured at 40°C to 60°C that satisfies the range of 24.0 to 30.0.

[0202] In comparison, it can be confirmed that the elastic sheets manufactured in Comparative Examples 1 to 4 do not satisfy the range of 2.0 to 2.5 in the elastic modulus at a compression ratio of 40% measured at 40°C to 60°C, and / or do not satisfy the range of 24.0 to 30.0 in the elastic modulus at a compression ratio of 70% measured at 40°C to 60°C.

[0203] Evaluation Example 2: Evaluation of Compression Ratio Changes According to Temperature Changes

[0204] For the elastic sheets manufactured in the above Example 1, the change in elasticity at compression ratios of 40% and 70% was measured as the temperature changed from 40°C to 60°C, and the results are shown in Table 2 below, denoted as Examples 1-1 to 1-3. At this time, the compression ratio and elasticity were measured in the same manner as Evaluation Example 1, and for the elastic sheets according to the above Examples 1-1 to 1-3 and the elastic sheets of Comparative Examples 1 to 4, it was evaluated whether fracture occurred at each measurement temperature.

[0205] Measurement temperature (℃) Elasticity modulus at 40% compression ratio (MPa) Elasticity modulus at 70% compression ratio (MPa) Whether fracture occurred Remarks 402.529.5 No fracture Example 1-1502.026.0 No fracture Example 1-2602.524.0 No fracture Example 1-3403.725.3 Fracture occurred Comparative example 1501.526.0 Fracture occurred Comparative example 2402.220.2 Fracture occurred Comparative example 3602.435.8 Fracture occurred Comparative example 4

[0206] Referring to Table 2 above, it can be confirmed that the elastic sheet manufactured in Example 1 satisfies the range of 2.0 to 2.5 in the elastic modulus at a compression ratio of 40% and the range of 24.0 to 30.0 in the elastic modulus at a compression ratio of 70%, even when the temperature changes in the range of 40 ℃ to 60 ℃ as in Examples 1-1 to 1-3, and that no breakage occurs when the elastic modulus is measured. On the other hand, it was confirmed that when the measurement temperature exceeds 60 ℃, the elastic sheet may break at one or more of the compression ratios of 40% and 70% when pressurized to measure the elastic modulus, and when the measurement temperature is less than 40 ℃, the elastic sheet may become too hard, making it difficult to measure the elastic modulus, or the elastic modulus may change too rapidly depending on the compression ratio.

[0207] Meanwhile, in order for the elastic sheet to have an appropriate level of elasticity, the measurement temperature can be adjusted to a range of 40°C to 60°C, and when the elastic sheet satisfies the aforementioned equation 1, it can be confirmed that it exhibits a property behavior that can be suitably used depending on the internal environment of the all-solid-state secondary battery.

[0208] In comparison, it can be confirmed that the elastic sheets manufactured in Comparative Examples 1 to 4 do not satisfy at least one of the properties of an elastic modulus of 2.0 to 2.5 at a compression ratio of 40% measured in the range of 40°C to 60°C and an elastic modulus of 24.0 to 30.0 at a compression ratio of 70%, and thus breakage occurs when measuring the compression ratio.

[0209] Evaluation Example 3: Evaluation of Lifetime Characteristics of All-Solid-State Secondary Batteries

[0210] For the all-solid-state secondary batteries manufactured in Examples 1 to 4 and Comparative Examples 1 to 4, initial charge and discharge were performed by charging to an upper limit voltage of 4.25 V at a constant current of 0.1 C at each temperature of 40°C, 50°C, and 60°C as described in Table 3 below, and then discharging to an end voltage of 2.5 V at 0.1 C. Thereafter, charging at 0.33 C and discharging at 0.33 C in a voltage range of 2.5 V to 4.25 V at the temperatures described in Table 3 below were repeated 300 times or more, and the number of cycles at which the discharge capacity retention rate for the initial discharge dropped below 90% is shown in Table 3 below.

[0211] Cell life (cycle) at 40°C Cell life (cycle) at 50°C Cell life (cycle) at 60°C Example 1 >300 >300 >300 Example 2 >300 >300 >300 Example 3 >300 >300 >300 Example 4 >300 >300 >300 Comparative Example 1 <100 <100 <100 Comparative Example 2 <100 <100 <100 Comparative Example 3 <100 <100 <100 Comparative Example 4 <100 <100 <100

[0212] Referring to Table 3 above, in the case of the all-solid-state secondary batteries in Examples 1 to 4, it can be confirmed that the life characteristics are excellent, as compared to Comparative Examples 1 to 4, the life characteristics evaluation shows a capacity retention rate of 90% or more for more than 300 cycles.

[0213] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0214] [Explanation of symbols]

[0215] 100: All-solid-state battery 200: Cathode

[0216] 201: Cathode current collector 203: Cathode active material layer

[0217] 300: solid electrolyte membrane 400: cathode

[0218] 401: Negative current collector 403: Negative active material layer

[0219] 400': Precipitation type cathode 404: Lithium metal layer

[0220] 405: Cathode coating layer 500: Elastic sheet

Claims

The elastic modulus at a compression ratio of 40% measured at 1.40 ℃ to 60 ℃ is 2.0 to 2.5, An elastic sheet for an all-solid-state secondary battery having an elastic modulus of 24.0 to 30.0 at a compression ratio of 70% measured at 40°C to 60°C.

2. In paragraph 1, The above elastic sheet is an elastic sheet for an all-solid-state secondary battery containing a polyurethane resin.

3. In paragraph 2, An elastic sheet for an all-solid-state secondary battery, wherein the glass transition temperature of the polyurethane resin is -70°C to -38°C.

4. In paragraph 1, The elastic modulus at 40% compression ratio measured at 40 ℃ is 2.3 to 2.5, and 4 An elastic sheet for an all-solid-state secondary battery having an elastic modulus of 26.5 to 30.0 at a compression ratio of 70% measured at 0°C.

5. In paragraph 1, The elastic modulus at a compression ratio of 40% measured at 50°C is 2.0 to 2.3, An elastic sheet for an all-solid-state secondary battery having an elastic modulus of 25.0 to 26.5 at a compression ratio of 70% measured at 50°C.

6. In paragraph 1, The elastic modulus at a compression ratio of 40% measured at 60 ℃ is 2.3 to 2.5, An elastic sheet for an all-solid-state secondary battery having an elastic modulus of 24.0 to 25.0 at a compression ratio of 70% measured at 60°C.

7. In paragraph 1, An elastic sheet for an all-solid-state secondary battery satisfying the following equation 1. [Formula 1] x×T / 7 ≤ y ≤ x×T / 3.3 In the above equation 1, y represents the elastic modulus at a compression ratio of 70%, x represents the elastic modulus at a compression ratio of 40%, and T represents the measurement temperature.

8. In paragraph 7, The above T is an elastic sheet for an all-solid-state secondary battery having a temperature of 40°C to 60°C.

9. In paragraph 2, The above elastic sheet for an all-solid-state secondary battery further comprises elastic particles, An elastic sheet for an all-solid-state secondary battery, wherein the elastic particles are derived from alkyl acrylate, olefin, butadiene, isoprene, styrene, acrylonitrile, a copolymer thereof, or a combination thereof.

10. In paragraph 9, The average particle diameter D of the above elastic particles 50 An elastic sheet for an all-solid-state secondary battery having a thickness of 10 nm to 900 nm.

11. In paragraph 9, An elastic sheet for an all-solid-state secondary battery, wherein the elastic particles are contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the polyurethane resin.

12. In paragraph 2, The above elastic sheet for an all-solid-state secondary battery further comprises inorganic particles, An elastic sheet for an all-solid-state secondary battery, wherein the inorganic particles include alumina, titania, boehmite, barium sulfate, calcium carbonate, calcium phosphate, amorphous silica, mesoporous silica, fumed silica, crystalline glass particles, kaolin, talc, silica-alumina composite oxide particles, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, mica, magnesium oxide, or a combination thereof.

13. In paragraph 12, An elastic sheet for an all-solid-state secondary battery, wherein the inorganic particles are contained in an amount of 0.001 to 50 parts by weight based on 100 parts by weight of the polyurethane resin.

14. In paragraph 2, The above elastic sheet for an all-solid-state secondary battery further comprises an additive, The above additive is an elastic sheet for an all-solid-state secondary battery including an initiator, a crosslinking agent, a coupling agent, a stabilizer, or a combination thereof.

15. In paragraph 14, An elastic sheet for an all-solid-state secondary battery, wherein the additive is contained in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the polyurethane resin.

16. In paragraph 1, An elastic sheet for an all-solid-state secondary battery, wherein the average thickness of the elastic sheet is 100 ㎛ to 10 mm.

17. Bipolar; cathode; and Containing two or more unit cells including a solid electrolyte membrane positioned between the anode and the cathode; An all-solid-state secondary battery comprising an elastic sheet according to any one of claims 1 to 16 positioned between the unit cells and / or at the outermost edge of the unit cells.

18. In paragraph 17, The above cathode is negative current collector; and An all-solid-state secondary battery comprising a negative electrode coating layer positioned on the negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

19. In paragraph 18, An all-solid-state secondary battery further comprising a lithium metal layer formed by charging between the negative electrode current collector and the negative electrode coating layer.

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