Discharging and stabilizing treatment method and device for all-solid-state rechargeable battery materials

Abstract

The present invention relates to a discharging and stabilizing treatment method and treatment device for all-solid-state rechargeable battery materials, the method comprising: preparing a mixed solution containing an oil layer and a basic aqueous solution layer; and adding all-solid-state rechargeable battery material to the mixed solution.

Description

Method and apparatus for discharge and stabilization treatment of all-solid-state secondary battery materials

[0001] This invention relates to a method and apparatus for discharge and stabilization treatment of all-solid-state secondary battery materials.

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

[0003] Since commercially available lithium-ion batteries use electrolytes containing flammable organic solvents, there are safety issues where the battery may explode or catch fire in the event of collisions or penetrations.

[0004] Accordingly, all-solid-state secondary batteries utilizing solid electrolytes instead of liquid electrolytes are being proposed. All-solid-state secondary batteries are composed entirely of solid materials; they offer the advantages of safety by eliminating risks such as explosions caused by electrolyte leakage, and facilitate the fabrication of thin batteries. Furthermore, the reduction in negative electrode thickness enables improved high-speed charging and discharging performance, as well as the realization of high-voltage operation and high energy density.

[0005] As a method for recycling all-solid-state secondary batteries, we aim to provide a method for discharging and stabilizing all-solid-state secondary battery materials that is safe and can suppress or reduce the generation of environmental pollutants.

[0006] One embodiment provides a method for discharging and stabilizing an all-solid-state secondary battery material, comprising preparing a mixed solution containing an oil layer and a basic aqueous solution layer, and introducing an all-solid-state secondary battery material into the mixed solution.

[0007] Another embodiment provides a discharge and stabilization treatment apparatus for all-solid-state secondary battery materials, comprising a solution receiving portion that receives a mixed solution containing an oil layer and a basic aqueous solution layer.

[0008] According to one embodiment, as a method for recycling an all-solid-state secondary battery, a method for discharging and stabilizing an all-solid-state secondary battery material can be provided, which is safe and can suppress or reduce the generation of environmental pollutants.

[0009] FIGS. 1 to 3 are cross-sectional views schematically illustrating 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, and the present invention is defined only by the scope of the claims set forth below.

[0011] Unless otherwise specifically stated in this specification, when a part such as a layer, film, region, plate, etc. is described as being "on" another part, this includes not only cases where it is "immediately on" another part, but also cases where there is another part in between.

[0012] Unless otherwise specified in this specification, a singular form may also include a plural form. Additionally, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0013] In this specification, "combination of these" may mean a mixture of components, a laminate, a composite, a copolymer, an alloy, a blend, and a reaction product, etc.

[0014] Unless otherwise defined in this specification, particle size may be the average particle size. Additionally, particle size refers to the average particle size (D) which means the diameter of the particle whose cumulative volume in the particle size distribution is 50 volume%. 50 It means ). Average particle size (D 50The measurement can be performed using methods widely known to those skilled in the art, for example, by using a particle size analyzer, or by using transmission electron microscope (TEM) or scanning electron microscope (SEM) images. Alternatively, the measurement may be performed using a measuring device utilizing dynamic light scattering, and after analyzing the data to count the number of particles for each particle size range, the average particle size (D) is calculated from this. 50 ) values ​​can be obtained. Alternatively, it can be measured using the laser diffraction method. When measuring by the laser diffraction method, more specifically, after dispersing the particles to be measured in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), and ultrasound at approximately 28 kHz is irradiated at an output of 60 W. Then, the average particle size (D) at the 50% reference of the particle size distribution in the measuring device 50 ) can be produced.

[0015] The terms "include," "equip," or "have" used herein are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0016] In addition, the term “layer” here includes not only shapes formed on the entire surface when viewed in a plan view, but also shapes formed on some surfaces.

[0017] The term “metal” is interpreted as a concept that includes ordinary metals, transition metals, and metalloids (semimetals).

[0018] Discharge and stabilization treatment method for all-solid-state secondary battery materials

[0019] One embodiment provides a method for discharging and stabilizing an all-solid-state secondary battery material, comprising preparing a mixed solution containing an oil layer and a basic aqueous solution layer, and introducing an all-solid-state secondary battery material into the mixed solution.

[0020] All-solid-state secondary batteries contain a large amount of valuable resources, so recycling through various methods is anticipated. However, due to the inclusion of high-energy metallic materials, there is a high possibility of frequent explosions or fires, which consequently presents technical difficulties in recycling all-solid-state secondary battery materials.

[0021] Conventional lithium secondary batteries performed discharge using methods such as salt water discharge, and because it is the most classic method that is safe and can suppress risks, salt water discharge is still used in most lithium secondary batteries.

[0022] However, all-solid-state secondary battery materials are highly vulnerable to water and atmospheric moisture. In particular, if all-solid-state secondary batteries using sulfide-based solid electrolytes or lithium metal all-solid-state secondary batteries are discharged in the same manner as conventional saltwater discharge, it is dangerous due to the very high likelihood of generating large amounts of H2S gas or toxic substances. Furthermore, all-solid-state secondary batteries using lithium metal also pose a risk of fire or explosion when exposed to the atmosphere and moisture. Meanwhile, all-solid-state secondary batteries using oxide-based solid electrolytes also contain hazardous substances.

[0023] There is a need for safe methods to recycle all-solid-state secondary battery materials, as well as processes that do not generate environmental pollutants. In particular, while the application of general discharge processes is required for all-solid-state secondary batteries, safe discharge and storage methods have not yet been developed.

[0024] Similar to conventional lithium-ion batteries, a discharge process using brine can be applied, but this is unsafe and generates large amounts of hazardous substances. Accordingly, there is a need to develop a discharge or stabilization treatment method for all-solid-state secondary batteries that ensures safety while being easy to handle. Furthermore, this invention aims to provide a treatment method that enables the simultaneous discharge and storage of all-solid-state secondary battery cells, packs, and modules.

[0025] Accordingly, in one embodiment, by using a mixed solution containing an oil layer and a basic aqueous solution layer to discharge and stabilize the all-solid-state secondary battery material, the all-solid-state secondary battery can be safely stored and the all-solid-state secondary battery material can also be discharged.

[0026] One embodiment proposes a method for discharging and stabilizing an all-solid-state secondary battery material, comprising the following process for recycling the all-solid-state secondary battery material.

[0027] First, a mixed solution containing an oil layer and a basic aqueous layer is prepared. By utilizing this mixed solution containing the oil layer and the basic aqueous layer in the recycling technology for all-solid-state secondary batteries, stability can be ensured, handling is easy, and the all-solid-state secondary battery material can be discharged and stabilized in an eco-friendly manner without generating environmental pollutants such as H2S gas or toxic gases.

[0028] In one embodiment, the oil layer contains oil, and the basic aqueous solution layer contains a basic aqueous solution. In this case, the oil may have a lower specific gravity than the basic aqueous solution, and the basic aqueous solution may have a higher specific gravity than the oil. As a result, the oil layer may be located at the top of the mixed solution, and the basic aqueous solution layer may be located at the bottom of the mixed solution. The oil layer containing oil and the basic aqueous solution layer containing a basic aqueous solution exist separated within the mixed solution due to different physical properties, and exhibit a phenomenon in which the oil layer and the basic aqueous solution layer each form individual layers. Through this, the oil layer located at the top of the mixed solution can primarily prevent toxic substances such as H2S gas from leaking out, thereby ensuring safety, and the basic aqueous solution layer located at the bottom of the mixed solution can reduce or suppress the generation of H2S itself, thereby obtaining the same effect as the conventional salt discharge method of lithium secondary batteries.

[0029] When the above all-solid-state secondary battery material is immersed in the above-mentioned mixed solution, H2S generated during the immersion process can be dissolved in the basic aqueous solution located at the bottom of the above-mentioned mixed solution and changed into a sulfur anion form, and since sulfur elements remain in the solution, the generation of H2S itself can be suppressed and the sulfide-based solid electrolyte can be stabilized.

[0030] In addition, since the oil layer is located on top of the basic aqueous solution layer due to the difference in specific gravity, the oil layer acts as a coating layer, preventing the sulfide-based solid electrolyte that may be included in the all-solid-state secondary battery material from being exposed to the atmosphere or moisture, thereby further suppressing the generation of H2S.

[0031] In one embodiment, the thickness ratio of the oil layer and the basic aqueous solution layer may be 3:7 to 7:3, for example, 3:7 to 5:5. That is, the thickness of the basic aqueous solution layer may be greater than the thickness of the oil layer. When this is satisfied, the effect of the coating layer by the oil layer and the effect of suppressing the generation of H2S by the basic aqueous solution layer can be harmonized with each other.

[0032] For example, the oil may include mineral oil, vegetable oil, or a combination thereof. The types of mineral oil and vegetable oil are not specifically limited, and any commonly available type of mineral oil and vegetable oil may be used. In particular, examples of vegetable oil include palm oil, coconut oil, soybean oil, cottonseed oil, camellia oil, or combinations thereof, with palm oil being a representative example. If these conditions are met, it is advantageous for ensuring safety by effectively preventing the leakage of toxic substances to the outside, and it may enable the recycling of all-solid-state secondary battery materials in an environmentally friendly manner.

[0033] For example, the basic aqueous solution may include a basic compound, and the basic compound may include NaOH, KOH, LiOH, or a combination thereof. If this is satisfied, the generation of toxic substances itself can be reduced or suppressed, thereby ensuring safety and enabling the recycling of all-solid-state secondary battery materials in an environmentally friendly manner.

[0034] For example, the basic aqueous solution may have a pH of 10 or higher, for example, a pH of 10 to 14, a pH of 10 to 13, or a pH of 11 to 13. In order to remove H2S that may occur when using a sulfide-based solid electrolyte, the pH of the basic aqueous solution must meet a requirement of 10 or higher, and this can effectively reduce the generation of toxic substances, which is advantageous for ensuring safety.

[0035] In one embodiment, the mixed solution may be obtained by preparing a first solution in which oil is mixed with a first solvent and a second solution in which a basic compound is mixed with a second solvent, mixing the first solution and the second solution, and then leaving the mixture for 5 minutes or more, 30 minutes to 24 hours, 40 minutes to 20 hours, or 1 hour to 10 hours. At this time, the first solvent is not particularly limited as long as it does not react with the sulfide-based solid electrolyte, and octyl acetate (OA) may be used as a representative example of the first solvent. Additionally, the second solvent may be water, which is a water-soluble solvent that dissolves the basic compound but does not dissolve the oil.

[0036] Next, an all-solid-state secondary battery material is added to the above-mentioned mixed solution. In one embodiment, the all-solid-state secondary battery material may include a sulfide-based solid electrolyte. Additionally, as an example, the all-solid-state secondary battery material may include an all-solid-state secondary battery cell, an all-solid-state secondary battery module, an all-solid-state secondary battery pack, an all-solid-state secondary battery process scrap, an all-solid-state secondary battery decomposition product, or a combination thereof. That is, the cell, pack, module, or process scrap of the all-solid-state secondary battery may be added whole to the above-mentioned mixed solution for discharge and stabilization treatment, or the decomposition product obtained by decomposing the electrode plate, etc. of the all-solid-state secondary battery may be added for discharge and stabilization treatment. According to one embodiment, since the all-solid-state secondary battery material does not require multiple process treatments or a separate additional process for treating toxic substances such as H2S gas, the cost of recycling the all-solid-state secondary battery material can be effectively reduced.

[0037] In one embodiment, the immersion may involve immersing the all-solid-state secondary battery material in the mixed solution, for example, the immersion may involve immersing the all-solid-state secondary battery material so that it is positioned in the basic aqueous layer of the mixed solution. In this way, by immersing the entire all-solid-state secondary battery material so that it is submerged in the basic aqueous layer, the generation of toxic substances such as H2S from the all-solid-state secondary battery material can be reduced or suppressed, safety can be effectively ensured, and the same effect as the conventional salt water discharge method can be obtained.

[0038] In one embodiment, the immersion may be performed in a range where the temperature of the mixed solution satisfies 0 to 30 ℃, 5 to 25 ℃, or 10 to 20 ℃. By immersing the all-solid-state secondary battery material in a mixed solution at a low temperature to satisfy the above range, stability can be improved.

[0039] For example, the immersion may be performed for 3 minutes to 1 week, 5 minutes to 3 days, 10 minutes to 24 hours, 10 minutes to 10 hours, or 10 minutes to 2 hours. If this is satisfied, the effect of blocking the generation of toxic substances such as H2S and preventing the occurrence of fire or explosion can be maximized.

[0040] In one embodiment, after the above-mentioned addition, the method may further include a discharge treatment for the all-solid-state secondary battery material, for example, the discharge treatment may be performed for 1 to 3 weeks, 2 to 2 weeks, or 1 to 2 weeks from the time the all-solid-state secondary battery material is added to the mixed solution. Since a fire or explosion may occur if the battery is recycled immediately without being discharged, a discharge treatment may be required before recycling the battery.

[0041] In conventional lithium secondary batteries, discharge treatment was performed using brine; however, in the case of all-solid-state secondary batteries using sulfide-based solid electrolytes, immersing the all-solid-state secondary battery material in brine or aqueous solutions generates toxic substances such as H2S gas, thus limiting its application. In contrast, according to one embodiment, by immersing the all-solid-state secondary battery for a long time in a mixed solution containing an oil layer and a basic aqueous solution layer, the energy remaining in the all-solid-state secondary battery material can be effectively released. Consequently, problems such as those associated with the conventional brine discharge method do not occur, and the all-solid-state secondary battery material can be recycled and discharged in a safe and environmentally friendly manner.

[0042] In one embodiment, after the immersion, the method may further include separating and recovering one or more of the basic aqueous solution layer and the all-solid-state secondary battery material immersed in the basic aqueous solution layer and using them as raw materials for a recycling process. In this case, not only can the cost of recycling be reduced, but the basic aqueous solution and / or all-solid-state secondary battery material required for recycling can also be used as raw materials for the recycling process, making it environmentally friendly.

[0043] For example, after the above immersion, the method may further include recycling the mixed solution, for instance, separating and recovering the oil layer and the basic aqueous layer of the mixed solution for recycling. In this case, not only can the cost of recycling be reduced, but the mixed solution required for recycling can also be reused in the recycling process, making it environmentally friendly.

[0044] Discharge and stabilization treatment device for all-solid-state secondary battery materials

[0045] One embodiment provides a discharge and stabilization treatment apparatus for all-solid-state secondary battery materials, comprising a solution receiving portion that receives a mixed solution containing an oil layer and a basic aqueous solution layer.

[0046] Meanwhile, since the description of the discharge and stabilization treatment method for the all-solid-state secondary battery material can be applied identically to the discharge and stabilization treatment device for the all-solid-state secondary battery material, a detailed description of the overlapping components is omitted here.

[0047] For example, it may further include a supply unit for introducing an all-solid-state secondary battery material into the solution receiving unit.

[0048] For example, the oil layer may be located at the top of the solution receiving portion, and the basic aqueous solution layer may be located at the bottom of the solution receiving portion.

[0049] In a method for discharging and stabilizing an all-solid-state secondary battery material according to one embodiment, the all-solid-state secondary battery of the all-solid-state secondary battery material may include the aforementioned positive electrode; a negative electrode; and a solid electrolyte membrane located between the positive electrode and the negative electrode.

[0050] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to one embodiment. Referring to FIG. 1, the all-solid-state secondary battery (100) may have a structure in which an electrode assembly is housed in a battery case, wherein the electrode assembly is stacked and includes a negative electrode (400) comprising a negative electrode current collector (401) and a negative electrode active material layer (403); a solid electrolyte membrane (300); and a positive electrode (200) comprising a positive electrode active material layer (203) and a positive electrode current collector (201). 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). FIG. 1 illustrates a unit cell comprising a cathode (400), a solid electrolyte membrane (300), and a positive electrode (200). However, as illustrated in FIG. 3, a solid-state secondary battery may be manufactured by stacking two unit cells, or by stacking two or more unit cells, for example, 2 to 100, 3 to 50, 4 to 20, etc. Additionally, the unit cell may include one or more cathodes, and likewise may include one or more solid electrolyte membranes and one or more positive electrodes. For example, the unit cell may be a monocell with a positive electrode / solid electrolyte membrane / cathode structure, or a bicell with a negative electrode / solid electrolyte membrane / positive electrode / solid electrolyte membrane / cathode structure.

[0051] anode

[0052] In one embodiment, it includes an anode current collector and an anode active material layer formed on the anode current collector. The anode active material layer includes an anode active material and may further include a binder and / or a conductive material. Alternatively, the anode active material layer may further include a solid electrolyte.

[0053] positive electrode active material

[0054] The above-mentioned positive electrode active material may be applied without limitation as long as it is commonly used in all-solid-state secondary batteries. For example, the above-mentioned positive electrode active material may use a compound capable of reversible intercalation and deintercalation of lithium, may include a lithium transition metal complex oxide, and may include a compound represented by any one of the following chemical formulas. 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).

[0055] The above-mentioned 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.

[0056] The above positive 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.

[0057] [Chemical Formula 1]

[0058] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0059] 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 Each is 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.

[0060] 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.

[0061] [Chemical Formula 2]

[0062] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0063] 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.

[0064] [Chemical Formula 3]

[0065] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0066] 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.

[0067] [Chemical Formula 4]

[0068] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0069] 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.

[0070] The above positive active material may be in the form of particles, and the average particle size (D) of the above positive active material 50 ) may be 1 μm to 25 μm, for example, 3 μm to 25 μm, 1 μm to 20 μm, 1 μm to 18 μm, 3 μm to 15 μm, or 5 μm to 15 μm. As an example, the anode active material has an average particle size (D 50 Fine particles with a diameter of 1 μm to 9 μm and an average particle size (D 50 It may include atoms having a particle size range of 10 μm to 25 μm. A positive electrode active material having this particle size range can be harmoniously mixed with other components within the positive electrode active material layer and can achieve high capacity and high energy density. Here, the average particle size is determined by selecting approximately 20 arbitrary particles from a scanning electron microscope image of the positive electrode active material, measuring their particle sizes (diameter, major axis, or length of the major axis), obtaining a particle size distribution, and determining the diameter (D) of the particle whose cumulative volume is 50 volume% in the particle size distribution. 50 It may be that ) was taken as the average particle size.

[0071] The above positive active material may be in the form of secondary particles formed by the aggregation of a plurality of primary particles, or in the form of single particles. In addition, the above positive active material may be spherical or have a shape close to spherical, or may be polyhedral or irregular in shape.

[0072] Meanwhile, the above-mentioned positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be described as a coating layer, a protective layer, etc., and may serve to lower the interfacial resistance between the positive electrode active material and the solid electrolyte particles. As an example, the buffer layer may include a lithium metal oxide, wherein the metal may be, for instance, 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 at lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles while improving the performance of the positive electrode active material by facilitating the movement of lithium ions and electron conduction.

[0073] The above positive active material may be included in an amount of 55% to 99% by weight with respect to 100% by weight of the above positive active material layer, for example, 65% to 95% by weight, or 75% to 91% by weight.

[0074] solid electrolyte

[0075] The solid electrolyte included in the above-mentioned positive electrode active material layer may be selected from, for example, sulfide-based solid electrolytes, oxide-based solid electrolytes, halide-based solid electrolytes, or combinations thereof. In particular, the solid electrolyte included in the above-mentioned positive electrode active material may be a sulfide-based solid electrolyte. The description below regarding solid electrolyte membranes may be applied in the same way to the solid electrolyte included in such a positive electrode active material layer.

[0076] With respect to 100 weight% of the above positive active material layer, the solid electrolyte may be included in an amount of 0.1 weight% to 35 weight%, for example, 1 weight% to 35 weight%, 5 weight% to 30 weight%, 8 weight% to 25 weight%, or 10 weight% to 20 weight%.

[0077] In addition, regarding the total weight of the positive active material and the solid electrolyte in the positive active material layer, 65% to 99% by weight of the positive active material and 1% to 35% by weight of the solid electrolyte may be included, for example, 80% to 90% by weight of the positive active material and 10% to 20% by weight of the solid electrolyte may be included. When the solid electrolyte is included in the positive electrode in such a content, the efficiency and lifespan characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0078] bookbinder

[0079] The above binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector. Representative examples include polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, 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., but are not limited thereto.

[0080] The content of the binder in the above positive active material layer may be approximately 0.1% to 5% by weight with respect to 100% by weight of the positive active material layer.

[0081] Challenge

[0082] The above positive active material layer may further include a conductive material. The conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples 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 in the form of metal powder or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0083] The content of the conductive material in the above positive active material layer may be 0% to 3% by weight, 0.01% to 2% by weight, or 0.1% to 1% by weight with respect to 100% by weight of the positive active material layer.

[0084] Aluminum foil may be used as the anode current collector, but is not limited thereto.

[0085] cathode

[0086] A negative electrode for an all-solid-state secondary battery according to one embodiment comprises a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector. The negative electrode active material layer comprises a negative electrode active material and may further comprise a binder and / or a conductive material. Alternatively, the negative electrode active material layer may optionally further comprise the aforementioned solid electrolyte.

[0087] The above-mentioned 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.

[0088] A 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 amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0089] 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 may be used.

[0090] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used, and the Si-based negative electrode active material may include silicon, a silicon-carbon composite, or SiO₂. 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.

[0091] For example, the negative electrode active material may include silicon-carbon composite particles. The average particle size (D) of the silicon-carbon composite particles 50 ) can be, for example, 0.5 μm to 20 μm. The average particle size (D 50 ) refers to the diameter of a particle whose cumulative volume in the particle size distribution is 50 volume%, as measured by a particle size analyzer. With respect to 100 weight% of the silicon-carbon composite particles, silicon may be included in an amount of 10 weight% to 60 weight% and carbon may be included in an amount of 40 weight% to 90 weight%. The silicon-carbon composite particles may, for example, comprise a core containing 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 µm, 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.

[0092] For example, the silicon-carbon composite particles may comprise a core containing silicon particles and crystalline carbon, and a carbon coating layer located on the surface of the core containing amorphous carbon. For example, in the silicon-carbon composite particles, the amorphous carbon may not be present in the core but 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-based pitch, mesophase pitch, petroleum-based pitch, coal-based oil, petroleum-based heavy oil, or a polymer resin (phenol resin, furan resin, polyimide resin, etc.). In this case, the content of the crystalline carbon may be 10% to 70% by weight and the content of the amorphous carbon may be 20% to 40% by weight with respect to 100% by weight of the silicon-carbon composite particles.

[0093] The core of the silicon-carbon composite particle 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.

[0094] The aforementioned silicon-carbon composite particles effectively suppress problems such as volume expansion, structural collapse, or particle fragmentation due to charging and discharging, thereby preventing the interruption of conductive paths, enabling high capacity and high efficiency, and making them advantageous for use under high voltage or high-speed charging conditions.

[0095] The above Si-based negative electrode active material or Sn-based negative electrode active material may 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 mixed and used, the mixing ratio may be 1:99 to 90:10 by weight.

[0096] The content of the negative electrode active material in the above negative electrode active material layer may be 95% to 99% by weight with respect to the total weight of the negative electrode active material layer.

[0097] In one embodiment, the negative active material layer further comprises a binder and optionally further comprises a conductive material. The content of the binder in the negative active material layer may be 1% to 5% by weight with respect to the total weight of the negative active material layer. Additionally, when further comprising a conductive material, the negative active material layer may comprise 90% to 98% by weight of the negative active material, 1% to 5% by weight of the binder, and 1% to 5% by weight of the conductive material.

[0098] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector. As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0099] Examples of the above-mentioned non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0100] The above-mentioned water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0101] When a water-based binder is used as the above-mentioned cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0102] The above conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of the above conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0103] As the above-mentioned cathode current collector, a material 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 may be used.

[0104] Precipitation type cathode

[0105] 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 during battery assembly, but where lithium metal, etc., is precipitated or electrodeposited on the negative electrode during battery charging, and which acts as the negative electrode active material.

[0106] 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) located on the negative electrode current collector. An all-solid-state secondary battery having such a precipitation type negative electrode (400') starts initial charging in a state where no negative electrode active material is present. Subsequently, during charging, a high-density lithium metal is precipitated or electrodeposited 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 can serve as a negative electrode active material. Accordingly, in a solid-state secondary battery that has undergone one or more charges, the precipitation type negative electrode (400') may include, for example, a negative electrode current collector (401), a lithium metal layer (404) located on the negative electrode current collector, and a negative electrode coating layer (405) located on the lithium metal layer. The lithium metal layer (404) refers to a layer in which lithium metal, etc. is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium electrodeposition layer, or a negative electrode active material layer.

[0107] The above-mentioned cathode coating layer (405) may be a lithium electrodeposition inducing layer or a cathode catalyst layer, and may include a lithium-friendly metal, a carbon material, or a combination thereof.

[0108] The above-mentioned lithium-friendly metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one of these or may be composed of several types of alloys. When the metal exists in the form of particles, its average particle size (D50 ) can be about 4 μm or less, and for example, 10 nm to 4 μm.

[0109] 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 micro beads, 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.

[0110] When the above-mentioned cathode 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 cathode coating layer (405) may, for example, include a carbon material supported with a catalyst metal, or may include a mixture of metal particles and carbon material particles.

[0111] The above cathode coating layer (405) may, for example, include the lithium-friendly metal and amorphous carbon, in which case the precipitation of lithium metal can be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-friendly metal is supported on amorphous carbon.

[0112] 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, ion conductive agents, etc.

[0113] The thickness of the above 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.

[0114] The above-described precipitation type cathode (400') may, for example, further include a thin film on the surface of the cathode current collector, that is, between the cathode current collector and the cathode 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 of these or composed of several types of alloys. The thin film can further flatten the precipitation shape 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.

[0115] 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.

[0116] 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, it can sufficiently perform the role of a lithium storage tank and prevent performance degradation due to an increase in battery volume.

[0117] When such a precipitation-type cathode is applied, the cathode coating layer (405) can protect the lithium metal layer (404) and suppress the precipitation growth of lithium deadlite. Accordingly, short circuits and capacity degradation of the all-solid-state battery are suppressed, and lifespan characteristics can be improved.

[0118] solid electrolyte membrane

[0119] In an all-solid-state secondary battery according to one embodiment, the solid electrolyte membrane (300) comprises a solid electrolyte, and the solid electrolyte may comprise, for example, a solid electrolyte selected from a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof.

[0120] Sulfide-based solid electrolytes

[0121] For example, the solid electrolyte membrane (300) may include a sulfide-based solid electrolyte with excellent ion conductivity. The sulfide-based solid electrolyte is, for example, Li2S-P2S5, Li2S-P2S5-LiX (where 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 and n are integers, and 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 may include a combination thereof.

[0122] 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. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. Additionally, ionic conductivity may be further improved by including other components such as SiS2, GeS2, B2S3, etc.

[0123] Mechanical milling or the solution method can be applied as mixing methods for sulfur-containing raw materials to manufacture sulfide-based solid electrolytes. Mechanical milling is a method in which starting materials are placed in a ball mill reactor and vigorously stirred to finely atomize and mix them. When using the solution method, starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, if heat treatment is performed after mixing, the crystals of the solid electrolyte can become more robust and the ionic conductivity can be improved. For example, a sulfide-based solid electrolyte can be manufactured by mixing sulfur-containing raw materials and heat-treating them two or more times; in this case, a robust sulfide-based solid electrolyte with high ionic conductivity can be produced.

[0124] A sulfide-based solid electrolyte according to one embodiment can be manufactured, for example, by mixing sulfur-containing raw materials and calcining at 120°C to 350°C for a first heat treatment, and by mixing the results of the first heat treatment and calcining at 350°C to 800°C for a second heat treatment. The first heat treatment and the second heat treatment can each be carried out 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. Through the first heat treatment, the effect of milling small raw materials can be obtained, and through the second heat treatment, the final solid electrolyte can be synthesized. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ion conductivity and robustness can be obtained, and such a solid electrolyte can be considered 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.

[0125] For example, the sulfide-based solid electrolyte may be in the form of particles and may contain argyrodite-type sulfides. These argyrodite-type sulfide-based solid electrolyte particles have an ionic conductivity of 10 at room temperature, which is the ionic conductivity of a typical liquid electrolyte. -4 to 10 -2 It has high ionic conductivity approaching the S / cm range. Furthermore, it can form a tight bond between the positive electrode active material and the solid electrolyte without causing a decrease in ionic conductivity, and can form a tight interface between the electrode and the solid electrolyte film. An all-solid-state secondary battery containing this can improve battery performance such as rate characteristics, Coulomb efficiency, and lifespan characteristics.

[0126] The above sulfide-based solid electrolyte may include, for example, an azirodite-type sulfide represented by Chemical Formula 11 below.

[0127] [Chemical Formula 11]

[0128] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0129] In the above chemical formula 11, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, 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, 1.5≤n≤5, 3≤f≤12, 0≤g<2, X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0130] For example, in Chemical Formula 11, a halogen element (X) may be necessarily included, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 11에 M 1 An element may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 11에서 M 3 can be understood as the element substituted at the P position, and 0 <e<1일 수 있다. 화학식 11에서 M 4 is substituted into the S position, for example, 0 <g<2일 수 있으며, S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 ga SO n In the case of SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and as an example, it can be SO4.

[0131] For example, in Chemical Formula 11, a+b+c+h=7, d+e=1, and f+g+h=6.

[0132] As a specific example, azirodite-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 a combination thereof may be included, but is not limited thereto.

[0133] An azirodite-type sulfide-based solid electrolyte can be prepared by mixing, for example, lithium sulfide and phosphorus sulfide, and optionally lithium halide. After mixing these, heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, preparing an azirodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment in which raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the result of the first heat treatment is mixed again and calcined at 350°C to 800°C.

[0134] Average particle size of sulfide-based solid electrolyte particles (D 50 ) may, for example, be 0.1 μm to 5.0 μm or 0.1 μm to 3.0 μm, and may be fine particles of 0.1 μm to 1.9 μm or coarse particles of 2.0 μm to 5.0 μm. The sulfide-based solid electrolyte particles may be a mixture of fine particles with an average particle size of 0.1 μm to 1.9 μm and coarse particles with an average particle size of 2.0 μm to 5.0 μm. The average particle size of the sulfide-based solid electrolyte particles may be measured using electron microscope images, for example, by measuring the size (diameter or length of the major axis) of about 20 particles from scanning electron microscope images to obtain a particle size distribution, where D50 It could be that it was calculated.

[0135] For example, the sulfide-based solid electrolyte may be included in an amount of 80% to 97% by weight with respect to 100% by weight of the solid electrolyte membrane, and may be included in an amount of, for example, 85% to 97% by weight, 90% to 97% by weight, 93% to 97% by weight, or 94% to 96% by weight. Within this range, excellent ionic conductivity can be secured while ensuring the durability of the battery.

[0136] oxide-based solid electrolytes

[0137] The solid electrolyte membrane (300) may include an oxide-based solid electrolyte. The oxide-based solid electrolyte is, 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 may include a mixture thereof.

[0138] Halide-based solid electrolytes

[0139] 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 the ratio of the halogen element to all elements constituting the solid electrolyte may be 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.

[0140] The halide-based solid electrolyte may contain a 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 for example, may be Cl, Br, or a combination thereof. The halide-based solid electrolyte is, for example, Li a It can be represented as 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). The above halide-based solid electrolyte is, 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 It may include Cl6, or a combination thereof, but is not limited thereto.

[0141] bookbinder

[0142] A solid electrolyte membrane according to one embodiment may further include a binder. The binder is, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, 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, copolymers thereof, Or it may include a combination of these.

[0143] The binder may be included in an amount of 0.1% to 3% by weight relative to 100% by weight of the solid electrolyte membrane, for example, 0.5% to 2% by weight or 0.5% to 1.5% by weight. When the binder is included within the above range, the components within the solid electrolyte membrane can be well bonded without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0144] Other ingredients

[0145] The solid electrolyte membrane may optionally further include other components such as alkali metal salts, and / or ionic liquids, and / or conductive polymers.

[0146] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the above solid electrolyte membrane may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt can improve ion conductivity by improving the lithium ion mobility of the solid electrolyte membrane.

[0147] Lithium salts may be applied without limitation of type and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalateto)borate (LiBOB), lithium difluoro(oxalateto)borate (LiDFOB), lithium difluorobis(oxalateto)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or combinations thereof.

[0148] For example, the above 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.

[0149] Ionic liquids are salts or room temperature molten salts that have a melting point below room temperature, are in a liquid state at room temperature, and consist only of ions.

[0150] 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.

[0151] The above ionic liquid may include, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolinium bis(trifluoromethylsulfonyl)amide, 1-ethyl-3-methylimidazolinium bis(trifluoromethylsulfonyl)amide, or a combination thereof.

[0152] The weight ratio of the solid electrolyte to the ionic liquid in the above solid electrolyte membrane may be 0.1:99.9 to 90:10, and 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 increasing 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.

[0153] The shape of the above-described all-solid-state secondary battery is not particularly limited and may be, for example, coin-type, button-type, sheet-type, stacked-type, cylindrical-type, flat-type, etc. Furthermore, the above-described all-solid-state secondary battery can be applied to large batteries used in electric vehicles, etc. For example, the above-described 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, for example, in electric bicycles or power tools. Furthermore, the above-described all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0154] Examples and comparative examples of the present invention are described below. The following examples are merely illustrative of the present invention, and the present invention is not limited to the following examples.

[0155] Example 1

[0156] A basic aqueous solution was prepared by mixing NaOH with water to adjust the pH to 11. Mineral oil was mixed into the basic aqueous solution and left for several hours to prepare a mixed solution containing an oil layer and a basic aqueous layer, which were separated into an oil layer and a basic aqueous layer.

[0157] As an all-solid-state secondary battery module and pack that has been used up and requires recycling, a module manufactured using Li6PS5Cl, an azirodite-type solid electrolyte, was immersed in the above-mentioned mixed solution at 20°C for 10 minutes, and then discharged for 1 week.

[0158] Next, the all-solid-state secondary battery module and pack were separated and recovered from the mixed solution to be used as raw materials for the recycling process.

[0159] Example 2

[0160] Except for adjusting the pH of the basic aqueous solution to pH 8 when preparing the above mixed solution, the all-solid-state secondary battery module and pack were immersed in the mixed solution and discharged in substantially the same manner as in Example 1, and the all-solid-state secondary battery module and pack were separated and recovered from the mixed solution.

[0161] Comparative Example 1

[0162] All-solid-state secondary battery modules and packs were immersed in the solution and discharged in a manner substantially identical to Example 1, except that only mineral oil was used instead of the above-mentioned mixed solution and a basic aqueous solution was not used, and the all-solid-state secondary battery modules and packs were separated and recovered from the mineral oil.

[0163] Comparative Example 2

[0164] Except for using a brine solution instead of the above mixed solution, the all-solid-state secondary battery module and pack were immersed in a brine solution and discharged in substantially the same manner as in Example 1, and the all-solid-state secondary battery module and pack were separated and recovered from the brine solution.

[0165] Evaluation Example 1: Evaluation of Hydrogen Sulfide Gas Leakage Amount

[0166] During the recycling process of the all-solid-state secondary battery modules and packs of Examples 1 and 2 and Comparative Examples 1 and 2, the amount of hydrogen sulfide (H2S) gas leakage was measured using a hydrogen sulfide detector (Manufacturer: Honeywell, Model: PGM-1860) and evaluated according to the following criteria, and is shown in Table 1 below.

[0167] If the H2S gas leakage is 5 ppm or less: ○

[0168] H2S gas leakage of 50 ppm to 99 ppm: △

[0169] When the H2S gas leakage is 100 ppm to 300 ppm: ×

[0170] Evaluation of H2S Gas Outflow Example 1 ○ Example 2 △ Comparative Example 1 × Comparative Example 2 ×

[0171] Referring to Table 1 above, it can be seen that in the case of Comparative Examples 1 and 2, the amount of H2S gas leakage is large. Therefore, it can be seen that a risk issue may arise due to the H2S gas generated during the work process, and also that an environmental pollution problem may occur.

[0172] On the other hand, in the case of Examples 1 and 2, it can be confirmed that the amount of H2S gas leakage is relatively small compared to Comparative Examples 1 and 2. Therefore, it can be seen that not only is it safe because there is no or minimal problem with H2S gas leakage during the operation process, but there is also no problem with environmental pollution.

[0173] In particular, in the case of Example 1, which uses a second solution that is a basic aqueous solution with a pH of 10 or higher, it can be confirmed that the amount of H2S gas leakage is smaller compared to Example 2, which uses a second solution that is a basic aqueous solution with a pH of less than 10. Accordingly, in the case of Example 1, it can be seen that the generation of H2S gas is most effectively suppressed, making the working environment very safe and eliminating environmental pollution issues, so the all-solid-state secondary battery material can be discharged, stabilized, and recycled in the most desirable way.

[0174] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts defined in the following claims are also included within the scope of the present invention.

[0175] [Explanation of the symbol]

[0176] 100: All-solid-state battery 200: Cathode

[0177] 201: Positive current collector 203: Positive active material layer

[0178] 300: Solid electrolyte membrane 400: Cathode

[0179] 401: Cathode current collector 403: Cathode active material layer

[0180] 400': Precipitation type cathode 404: Lithium metal layer

[0181] 405: Cathode coating layer 500: Elastic sheet

Claims

1. Prepare a mixed solution containing an oil layer and a basic aqueous solution layer, and A method for discharging and stabilizing an all-solid-state secondary battery material, comprising introducing the all-solid-state secondary battery material into the above-mentioned mixed solution.

2. In Paragraph 1, The above oil layer is located on top of the above mixed solution, and A method for discharging and stabilizing an all-solid-state secondary battery material in which the above basic aqueous solution layer is located at the bottom of the above mixed solution.

3. In Paragraph 1, A method for discharging and stabilizing an all-solid-state secondary battery material, wherein the above-mentioned input is immersing the all-solid-state secondary battery material in the above-mentioned mixed solution.

4. In Paragraph 3, A method for discharging and stabilizing an all-solid-state secondary battery material in which the above immersion is performed in a range in which the temperature of the above mixed solution satisfies 0 ℃ to 30 ℃.

5. In Paragraph 3, The above immersion is a discharge and stabilization treatment method for all-solid-state secondary battery materials performed for 3 minutes to 1 week.

6. In Paragraph 1, A method for discharging and stabilizing an all-solid-state secondary battery material, further comprising discharging the all-solid-state secondary battery material after the above input.

7. In Paragraph 6, The above discharge treatment is a method for discharging and stabilizing an all-solid-state secondary battery material, performed for 1 day to 3 weeks from the time the all-solid-state secondary battery material is introduced into the mixed solution.

8. In Paragraph 2, A method for discharging and stabilizing an all-solid-state secondary battery material, wherein the above-mentioned input is to immerse the all-solid-state secondary battery material in the basic aqueous layer of the above-mentioned mixed solution.

9. In Paragraph 8, A method for discharging and stabilizing a solid-state secondary battery material, further comprising, after the above immersion, separating and recovering one or more of the basic aqueous solution layer and the solid-state secondary battery material immersed in the basic aqueous solution layer and using them as raw materials for a recycling process.

10. In Paragraph 1, A method for discharging and stabilizing an all-solid-state secondary battery material, further comprising recycling the mixed solution after the above input.

11. In Paragraph 1, A method for discharging and stabilizing all-solid-state secondary battery materials, further comprising separating and recovering the oil layer and the basic aqueous layer of the mixed solution and recycling them after the above input.

12. In Paragraph 1, The above oil layer contains oil, and The above basic aqueous solution layer comprises a basic aqueous solution, The above oil has a lower specific gravity than the basic aqueous solution, and The above basic aqueous solution is a method for discharging and stabilizing an all-solid-state secondary battery material with a specific gravity higher than that of the above oil.

13. In Paragraph 1, The above oil layer contains oil, and A method for discharging and stabilizing an all-solid-state secondary battery material, wherein the above oil comprises mineral oil, vegetable oil, or a combination thereof.

14. In Paragraph 1, The above basic aqueous solution layer comprises a basic aqueous solution, The above basic aqueous solution contains a basic compound, and A method for discharging and stabilizing an all-solid-state secondary battery material, wherein the above basic compound comprises NaOH, KOH, LiOH, or a combination thereof.

15. In Paragraph 1, The above basic aqueous solution layer comprises a basic aqueous solution, The above basic aqueous solution is a method for discharging and stabilizing an all-solid-state secondary battery material having a pH of 10 or higher.

16. In Paragraph 1, A method for discharging and stabilizing a solid-state secondary battery material comprising a solid-state secondary battery cell, a solid-state secondary battery module, a solid-state secondary battery pack, solid-state secondary battery process scrap, a solid-state secondary battery decomposition product, or a combination thereof.

17. In Paragraph 1, A method for discharging and stabilizing an all-solid-state secondary battery material in which the thickness ratio of the oil layer and the basic aqueous solution layer is 3:7 to 7:

3.

18. In Paragraph 1, A method for discharging and stabilizing an all-solid-state secondary battery material in which the thickness of the basic aqueous solution layer is greater than the thickness of the oil layer.

19. In Paragraph 1, The above all-solid-state secondary battery material is a method for discharging and stabilizing an all-solid-state secondary battery material comprising a sulfide-based solid electrolyte.

20. A discharge and stabilization treatment apparatus for all-solid-state secondary battery materials comprising: a solution receiving portion for receiving a mixed solution containing an oil layer and a basic aqueous solution layer.

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