Method for recovering solid electrolyte, solid electrolyte recovered thereby, and all-solid-state battery comprising same

Abstract

The present invention relates to a method for recovering a solid electrolyte, a solid electrolyte recovered thereby, and an all-solid-state battery comprising same. More specifically, the method comprises: grinding all-solid-state battery waste in a moisture-controlled atmosphere; dissolving the ground product in a polar solvent to prepare a mixture; filtering the mixture to recover a liquid; analyzing the components of the recovered liquid to adjust the liquid to a desired composition ratio; drying the adjusted liquid to remove the solvent; and heat-treating the powder with the solvent removed.

Description

Method for recovering a solid electrolyte, solid electrolyte recovered thereby, and all-solid-state battery including the same

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

[0002]

[0003] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in information and communication devices, but also in the automotive sector. Safety is particularly important in the automotive sector, as it is a life-threatening issue.

[0004] Recently, all-solid-state batteries have been proposed, replacing the electrolyte in lithium-ion batteries with solid electrolytes. By eliminating the use of flammable organic dispersion media, all-solid-state batteries can significantly reduce the risk of fire or explosion in the event of a short circuit.

[0005] Because the key raw materials required for all-solid-state battery manufacturing must be obtained from natural resources, environmental destruction and pollution inevitably follow the raw material extraction process. Therefore, there is a pressing need to develop technologies to recover and recycle raw materials from spent batteries.

[0006]

[0007] The problem to be solved by the present invention is to provide a method for recovering a high-purity solid electrolyte from all-solid-state battery waste.

[0008] Another problem to be solved by the present invention is to provide a method for recovering a solid electrolyte with improved moisture stability.

[0009] Another problem that the present invention seeks to solve is to provide a more environmentally friendly and economical method for recovering solid electrolyte.

[0010]

[0011] A method for recovering a solid electrolyte according to the concept of the present invention may include: crushing all-solid-state battery waste in a moisture-controlled atmosphere; dissolving the crushed result in a polar solvent to prepare a mixture; filtering the mixture to recover a liquid; analyzing the components of the recovered liquid to adjust the liquid to a desired composition ratio; drying the adjusted liquid to remove the solvent; and heat-treating the powder from which the solvent has been removed.

[0012] A solid electrolyte according to another concept of the present invention can be recovered according to the above-described solid electrolyte recovery method.

[0013] An all-solid-state battery according to another concept of the present invention may include a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer. The solid electrolyte layer may include a solid electrolyte recovered according to the above-described solid electrolyte recovery method.

[0014]

[0015] The present invention can more safely separate and recover solid electrolytes by crushing all-solid-state battery waste while blocking moisture. According to one embodiment of the present invention, the desired solid electrolyte can be recovered more effectively with just a simple process of adjusting the composition ratio during the solid electrolyte recovery process. The solid electrolyte recovered according to one embodiment of the present invention can have high purity. Therefore, the high-purity solid electrolyte recovered according to one embodiment of the present invention can be directly used in the all-solid-state battery manufacturing process and recycled. Consequently, a more economical and environmentally friendly method for recycling solid electrolytes can be provided.

[0016]

[0017] Figure 1 is a flowchart for explaining a method for recovering a solid electrolyte according to one embodiment of the present invention.

[0018] FIG. 2a and FIG. 2b are cross-sectional views illustrating an all-solid-state battery according to embodiments of the present invention.

[0019]

[0020] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0021] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0022] Embodiments described herein will be described with reference to cross-sectional and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for the purpose of effectively explaining the technical contents. Accordingly, the regions illustrated in the drawings have a schematic nature, and the shapes of the regions illustrated in the drawings are intended to illustrate specific shapes of regions of the device and are not intended to limit the scope of the invention. Although terms such as first, second, and third are used to describe various components in various embodiments of the present specification, these components should not be limited by such terms. These terms are used only to distinguish one component from another. The embodiments described and illustrated herein also include complementary embodiments thereof.

[0023] The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise. As used herein, the words "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0024] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0025] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0026]

[0027] Method for recovering solid electrolyte

[0028] Figure 1 is a flowchart for explaining a method for recovering a solid electrolyte according to one embodiment of the present invention.

[0029] Referring to FIG. 1, a method for recovering a solid electrolyte according to an embodiment of the present invention may include: crushing all-solid-state battery waste in a moisture-controlled atmosphere (S20); dissolving the crushed result in a polar solvent (S30) to prepare a mixture; filtering the mixture to recover a liquid (S40); analyzing the components of the recovered liquid to adjust the liquid to a desired composition ratio (S50); drying the adjusted liquid (S60) to remove the solvent; and heat-treating the powder from which the solvent has been removed (S70).

[0030] A method for recovering a solid electrolyte according to one embodiment of the present invention may further include disassembling (S10) an all-solid-state battery module or pack prior to the crushing.

[0031] The above module may include a plurality of battery cells. The pack may include a plurality of battery modules and may include various control and protection systems such as a BMS (Battery Management System) and a cooling system.

[0032] All-solid-state battery waste can be crushed (S20) in a moisture-controlled atmosphere.

[0033] The above-mentioned all-solid-state battery waste may include at least one of a cell and process scrap. The battery cell may have a cylindrical, square, pouch-shaped, or coin-shaped shape. The process scrap may be waste generated during the manufacturing process of the all-solid-state battery.

[0034] The purpose of crushing battery waste in the above moisture-controlled atmosphere (S20) is to more safely crush all-solid-state batteries, which are vulnerable to moisture. This is because the toxic gas hydrogen sulfide (H2S) can be generated by a side reaction between sulfur contained in the battery waste and moisture in the atmosphere. According to one embodiment of the present invention, by crushing battery waste while preventing contact with moisture, the generation of hydrogen sulfide (H2S) can be fundamentally blocked. This provides a method for recovering a solid electrolyte with improved moisture stability.

[0035] The above moisture control atmosphere may be an inert gas atmosphere containing at least one selected from nitrogen, argon, helium, neon, krypton, xenon, and radon.

[0036] Alternatively, the moisture control atmosphere may be a dry room atmosphere. The dry room atmosphere may have a relative humidity of 10% or less and a dew point of -10°C or less.

[0037] The above crushing (S20) may include crushing the battery waste into an appropriate size. The crushing process (S20) may crush the battery waste into a size of 1 cm or less. In one embodiment, a crushed product having an average size of 0.1 cm to 1 cm may be obtained.

[0038] The above-mentioned crushed product may include a cathode material including valuable metals such as Co, Ni, Mn, and Li, a cathode material including graphite, impurities such as Al, Cu, and Fe, and a solid electrolyte. The above-mentioned crushed product may include various substances depending on the type of battery waste.

[0039] The crushing (S20) may be performed using at least one selected from the group consisting of a jaw crusher, a cone crusher, a roll crusher, a hammer mill, a cut mill, a pin mill, an impact mill, a ball mill, and a shredder. In one embodiment, the crushing (S20) may be performed using a jaw crusher.

[0040] The above crushed product can be dissolved in a polar solvent (S30) to prepare a mixture.

[0041] The step of preparing the mixture (S30) may be to uniformly mix the pulverized product and the polar solvent to prepare the mixture. In other words, the mixture preparation process may be to agitate the pulverized product in the polar solvent by an agitator, so that the solid electrolyte contained in the pulverized product is dissolved in the polar solvent. In the mixture preparation process, the agitator may be a conventional agitator widely used in the art.

[0042] In one embodiment, the stirring may be performed at a rotation speed of 500 rpm to 3000 rpm for 1 to 3 hours, but is not limited thereto. Preferably, the rotation speed and stirring time may be appropriately adjusted until the solid electrolyte is sufficiently dissolved in the polar solvent.

[0043] The above polar solvent can be used to dissolve a solid electrolyte from a pulverized product containing various substances, as described above.

[0044] The polar solvent may include at least one selected from the group consisting of ethanol, methanol, propanol, butanol, dimethyl carbonate, ethyl acetate, 1,2-dimethoxyethane, propylene glycol dimethyl ether, tetrahydrofuran (THF), and acetonitrile (ACN). In one embodiment, the polar solvent may be ethanol, but is not particularly limited as long as it is a non-aqueous polar solvent capable of dissolving the solid electrolyte.

[0045] The above mixture can be filtered to recover the liquid (S40).

[0046] Filtering the mixture to recover the liquid (S40) may be to separate and recover the solid electrolyte present in a dissolved state in the polar solvent from the mixture.

[0047] The above filtration process can separate the liquid and solid by filtering the mixture. In other words, the filtration process can separate the liquid containing the solid electrolyte that is soluble in the polar solvent, and the solid containing the positive electrode material, the impurities, and the negative electrode material that are insoluble in the polar solvent. Thus, the supernatant (liquid) can be recovered through filtration, thereby obtaining the solid electrolyte described below.

[0048] The above filtration may be performed using a decanter (centrifuge), filter, or filter press. In one embodiment, the filtration may be performed by centrifugation at 1,000 rpm to 5,000 rpm for 10 to 30 minutes.

[0049] By analyzing the components of the recovered liquid, the liquid can be adjusted to the desired composition ratio (S50).

[0050] Through component analysis of the recovered liquid, the results of component and content analysis of the liquid can be obtained. The component analysis can be performed, for example, through an ICP mass spectrometry method or an ICP emission spectrometry method. In one embodiment, an ICP mass spectrometry method can be used.

[0051] After the component analysis of the recovered liquid is performed, the liquid can be adjusted to the desired composition ratio.

[0052] The above composition ratio adjustment may be a process of adjusting the content of the components contained in the liquid so that it is stoichiometrically consistent with the optimal composition ratio of the desired solid electrolyte. In other words, the composition ratio adjustment may be performed by measuring the content of the elements constituting the solid electrolyte contained in the liquid, and adding any missing components among the individual components contained in the liquid based on the measurement results to adjust the composition ratio.

[0053] Adjusting the composition ratio by adding the above-mentioned missing component may include adding at least one of a lithium (Li)-containing compound, a phosphorus (P)-containing compound, a sulfur (S)-containing compound, a halogen element-containing compound, and a metal (M)-containing compound to the recovered liquid. However, the present invention is not limited thereto, and a compound containing a specific component may be further added depending on the type of battery waste.

[0054] The lithium-containing compound may be, for example, Li2S, Li2S2, Li2S4, Li2S6, Li2S8, or a combination thereof.

[0055] The above-mentioned phosphorus-containing compound may be, for example, P2S5, PCl3, PCl5, PBr3, PBr5 or a combination thereof.

[0056] The above sulfur-containing compounds are, for example, S, SCl2, S2Cl2, S2Br Or it could be a combination of these.

[0057] The above halogen element-containing compound may be, for example, LiCl, LiBr, LiI or a combination thereof.

[0058] The metal-containing compound may be, for example, an M-containing sulfide. The above M may be candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), or bismuth (Bi).

[0059] The liquid with the adjusted composition ratio can be dried (S60) to remove the solvent.

[0060] The drying (S60) may include removing the solvent within the liquid by evaporating the liquid. When the solvent is removed through the drying process (S60), a solid product in powder form can be obtained. The drying may be performed using an evaporation method commonly used in the art.

[0061] The above drying process (S60) is not particularly limited, but may be performed at a temperature range of 25°C to 200°C. For example, the above drying process (S60) may be performed at a temperature of 25°C to 75°C, 50°C to 100°C, 75°C to 150°C, or 100°C to 200°C.

[0062] Additionally, the drying process (S60) is not particularly limited, but may be performed for 30 minutes to 3 hours. For example, the drying process (S60) may be performed for 30 minutes to 1 hour, 1 hour to 2 hours, or 2 hours to 3 hours.

[0063] If the temperature and execution time of the drying process (S60) are below the above range, the liquid may not be sufficiently dried. On the other hand, if the temperature and execution time of the drying process (S60) exceed the above range, the composition of the solid electrolyte described below may vary due to uneven vaporization of the liquid.

[0064] The solvent removed through the drying process (S60) can be recovered and reused as a polar solvent in the manufacturing process of the aforementioned mixture. According to one embodiment of the present invention, by reusing the solvent without further consumption, a more economical and environmentally friendly method for recovering a solid electrolyte can be provided.

[0065] The powder from which the above solvent has been removed can be heat treated (S70).

[0066] The heat treatment (S70) may be performed on powder from which the solvent has been removed through the drying process (S60) described above, thereby ultimately obtaining a solid electrolyte. According to one embodiment of the present invention, crystals of the solid electrolyte may grow through the heat treatment process (S70).

[0067] The above heat treatment process (S70) is not particularly limited, but may be performed at a temperature range of 400°C to 700°C. For example, the heat treatment temperature may be 400°C to 600°C, 450°C to 600°C, 500°C to 650°C, or 550°C to 700°C.

[0068] If the heat treatment process (S70) is performed at a temperature of 400°C or lower, non-uniform crystallization may occur, resulting in a non-uniform crystal structure in the final solid electrolyte. On the other hand, if the heat treatment process (S70) is performed at a temperature of 700°C or higher, an undesired crystal structure may be generated in the final solid electrolyte.

[0069] The heat-treated powder may include a solid electrolyte. Specifically, the heat-treated powder may include a sulfide-based solid electrolyte (e.g., Li6PS5Cl, Li6PS5Br) having an argyrodite-type crystal structure.

[0070] The above sulfide-based solid electrolyte can satisfy the desired optimal composition ratio through the composition ratio adjustment process described above. For example, the above sulfide-based solid electrolyte may have a composition ratio (molar ratio) of lithium (Li): phosphorus (P): sulfur (S): halogen element (e.g., Cl, Br, etc.) of 6:1:5:1. A more detailed description of the above solid electrolyte will be provided later.

[0071] The sulfide-based solid electrolyte in the heat-treated powder may have a purity of 90% or more. The heat-treated powder may not contain impurities or may contain trace amounts of impurities. Here, the impurities may include components other than lithium (Li), phosphorus (P), sulfur (S), and halogen elements (e.g., Cl, Br) that constitute the sulfide-based solid electrolyte. The types of impurities may also vary depending on the type of sulfide-based solid electrolyte contained in the battery waste. Accordingly, the solid electrolyte recovered through the above-described method for recovering the solid electrolyte has high purity and can be directly recycled in the manufacturing process of an all-solid-state battery without a separate additional process.

[0072]

[0073] The present invention can more safely separate and recover solid electrolytes by crushing all-solid-state battery waste while blocking moisture. According to one embodiment of the present invention, the desired solid electrolyte can be recovered more effectively with just a simple process of adjusting the composition ratio during the solid electrolyte recovery process. The solid electrolyte recovered according to one embodiment of the present invention can have high purity. Therefore, the high-purity solid electrolyte recovered according to one embodiment of the present invention can be directly used in the all-solid-state battery manufacturing process and recycled. Consequently, a more economical and environmentally friendly method for recycling solid electrolytes can be provided.

[0074]

[0075] solid electrolyte

[0076] A solid electrolyte according to one embodiment of the present invention may include a solid electrolyte recovered through the above-described solid electrolyte recovery method.

[0077] The solid electrolyte may have, for example, a particle shape. The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics.

[0078] A sulfide-based solid electrolyte can be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method, for example. In addition, a heat treatment can be performed after the treatment. The solid electrolyte can be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte can be, for example, a material containing sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte can be a material containing Li2S-P2S5. When using a material containing Li2S-P2S5 as a sulfide-based solid electrolyte material forming a solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0079] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z. m S n (m, n are positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “M” is one of P, Si, Ge, B, Al, Ga In), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I xIt may include at least one selected from (0≤x≤2).

[0080] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0081] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0082] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0083]

[0084] All-solid-state batteries

[0085] According to one embodiment of the present invention, the recovered solid electrolyte can be recycled in the manufacturing process of an all-solid-state battery. The solid electrolyte described above can be included in the solid electrolyte layer (300) described below.

[0086] FIG. 2a and FIG. 2b are cross-sectional views illustrating an all-solid-state battery according to embodiments of the present invention.

[0087] Referring to FIG. 2A, the all-solid-state battery may include a cathode layer (100), a cathode layer (200) facing the cathode layer (100), and a solid electrolyte layer (300) for an all-solid-state battery disposed between the cathode layer (100) and the cathode layer (200). However, the present invention is not limited thereto, and the all-solid-state battery (10) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the cathode layer (100) and the solid electrolyte layer (300) for an all-solid-state battery or between the cathode layer (200) and the solid electrolyte layer (300) for an all-solid-state battery.

[0088] The positive electrode layer (100) may include a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0089] The positive electrode current collector (110) can provide a reference surface on which the positive electrode active material layer (120) is arranged. The positive electrode current collector (110) can have a plate or foil shape. For example, the positive electrode current collector (110) can include indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0090] Unlike that illustrated in FIG. 2a, in one embodiment of the present invention, the positive electrode current collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode current collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode current collector (110) and the positive electrode active material layer (120).

[0091] The cathode active material may be a material that can reversibly absorb and desorb lithium ions. For example, the cathode active material may include, but is not limited to, lithium transition metal oxides such as lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganate, and lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. The cathode active materials may be used alone or as a mixture of two or more thereof.

[0092] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≤a≤1, 0≤b≤0.5), Li a E 1-b Bb O 2-c D c (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05), LiE 2-b B b O 4-c D c (0≤b≤0.5, 0≤c≤0.05), Li a Ni 1-b-c Co b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni 1-b-c Mr b B c D α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2), Li a Ni 1-b-c Mr b B c O 2-α F α (0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2), Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1), Li a Ni b Co c Mr d GeO2(0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1), Li a NiG b O2(0.9≤a≤1, 0.001≤b≤0.1), Li a CoG b O2(0.90≤a≤1, 0.001≤b≤0.1), Li a MnG bO2(0.90≤a≤1, 0.001≤b≤0.1), Li a Mn2GbO4(0.90≤a≤1, 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3(0≤f≤2), Li 3-f It may be a compound represented by any one of Fe2(PO4)3(0≤f≤2), LiFePO4. In these compounds, the capital letter “A” is Ni, Co, Mn, or a combination thereof, the capital letter “B” is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof, the capital letter “D” is O, F, S, P, or a combination thereof, the capital letter “E” is Co, Mn, or a combination thereof, the capital letter “F” is F, S, P, or a combination thereof, the capital letter “G” is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof, the capital letter “Q” is Ti, Mo, Mn, or a combination thereof, the capital letter “I” is Cr, V, Fe, Sc, Y, or a combination thereof, and the capital letter “J” is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0093] The cathode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt type structure among the lithium transition metal oxides described above. The "layered rock salt type structure" is, for example, a cubic rock salt type structure. <111> It is a structure in which oxygen atomic layers and metal atomic layers are alternately and regularly arranged in a direction, and thereby each atomic layer forms a two-dimensional plane. The "cubic rock salt structure" refers to the sodium chloride type (NaCl type) structure, which is a type of crystal structure, and specifically refers to a structure in which the face-centered cubic lattice (fcc) formed by each cation and anion is arranged with a displacement of half of the ridge of the unit lattice. Lithium transition metal oxides having this layered rock salt structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn z O2(NCM) (0 <x<1,0<y<1, 0<z<1, x+y+z=1) 등의 삼원계 리튬전이금속산화물일 수 있다. 양극 활물질이 층상암염형 구조를 갖는 삼원계 리튬전이금속산화물을 포함하는 경우, 전고체 전지의 에너지 밀도가 커지고 열안정성이 향상될 수 있다.

[0094] The above-described compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may also be a mixture of the above-described compound and a compound to which a coating layer is added. Meanwhile, the coating layer added to the surface of the positive electrode active material may include, for example, an oxide, a hydroxide, an oxyhydroxide, an oxycarbonate, or a hydroxycarbonate of the coating elements below. The compound forming the coating layer may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating layer may be selected within a range that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer may include, for example, a spray coating method or an immersion method.

[0095] When the positive electrode active material is a ternary lithium transition metal oxide such as NCA or NCM and contains nickel (Ni), the capacity density of the all-solid-state battery can be increased, which can reduce metal dissolution of the positive electrode active material in a charged state. As a result, the cycle characteristics of the all-solid-state battery in a charged state can be improved. Meanwhile, the “cycle characteristics” are characteristics indicating the degree to which the all-solid-state battery is deteriorated due to charge / discharge of the all-solid-state battery. An all-solid-state battery with high cycle characteristics can be deteriorated less due to charge / discharge, and an all-solid-state battery with low cycle characteristics can be deteriorated more due to charge / discharge.

[0096] The shape of the positive electrode active material may include particle shapes such as a sphere or an ellipsoid, for example. The particle size and content of the positive electrode active material are not particularly limited.

[0097] The solid electrolyte may have, for example, a particle shape. The solid electrolyte may be dispersed between positive electrode active materials. The solid electrolyte may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The sulfide-based solid electrolyte includes, for example, Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers, capital letter “Z” represents Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, capital letter “M” is one of P, Si, Ge, B, Al, Ga In), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x It may include at least one selected from (0≤x≤2).

[0098] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I xIt may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0099] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0100] Alternatively, the solid electrolyte included in the positive electrode active material layer (120) may be the same as the solid electrolyte included in the solid electrolyte layer (300) described later.

[0101] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte may be, for example, 15 GPa to 35 GPa.

[0102] The solid electrolyte included in the positive electrode active material layer (120) may have a smaller median particle size (D50) than the solid electrolyte included in the solid electrolyte layer (300) for an all-solid-state battery. For example, the median particle size (D50) of the solid electrolyte included in the positive electrode active material layer (120) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the median particle size (D50) of the solid electrolyte included in the solid electrolyte layer (300) for an all-solid-state battery. Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0103] A metal having a strong ionization tendency may exist on the surface of the solid electrolyte included in the positive electrode active material layer (120). However, the content of the metal having a strong ionization tendency may be less than the content of the metal having a strong ionization tendency on the surface of the sulfide-based solid electrolyte of the solid electrolyte layer (300) for an all-solid-state battery. For example, the solid electrolyte in the positive electrode active material layer (120) may not include a metal having a strong ionization tendency, or even if it includes a metal having a strong ionization tendency, the content thereof may be less than that of the solid electrolyte layer (300) for an all-solid-state battery.

[0104] The positive electrode active material layer (120) may include a conductive material. The conductive material may have conductivity without causing chemical changes in the all-solid-state battery, thereby increasing the conductivity of the positive electrode active material and the solid electrolyte. The conductive material may include a carbon-based material. For example, the conductive material may include one or more selected from graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0105] The positive electrode active material layer (120) may further include a binder. The binder may include a material for binding the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer (120) and improving bonding strength with the positive electrode current collector (110). For example, the binder may include polyvinylidene fluoride, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, or polymethyl methacrylate.

[0106] When the total amount of the positive electrode active material, the solid electrolyte, the conductive material, and the binder is 100 parts by weight, the positive electrode active material layer (120) may include 85 parts by weight to 92 parts by weight of the positive electrode active material. The positive electrode active material layer (120) may include 0.5 parts by weight to 1.5 parts by weight of the binder.

[0107] Within the positive electrode active material layer (120), the conductive material may be present in an amount of 1 to 50 parts by weight relative to 100 parts by weight of the solid electrolyte. If the conductive material is present in an amount less than 1 part by weight relative to 100 parts by weight of the solid electrolyte, the electrical conductivity of the positive electrode active material layer (120) may be reduced. If the conductive material is present in an amount greater than 50 parts by weight relative to 100 parts by weight of the solid electrolyte, the conductive material ratio may be excessively high, and thus a covering layer covering the surface of the solid electrolyte may not be properly formed.

[0108] According to embodiments, the positive electrode active material layer (120) may further include at least one additive selected from the group consisting of a filler, a coating agent, a dispersant, and an ion conductive auxiliary agent in addition to the above-described positive electrode active material, solid electrolyte, conductive agent, and binder.

[0109] The solid electrolyte layer (300) for an all-solid-state battery is disposed between the positive electrode layer (100) and the negative electrode layer (200) and may include a sulfide-based solid electrolyte having excellent lithium ion conductivity characteristics. The solid electrolyte layer (300) may include a solid electrolyte, a binder, etc. The solid electrolyte may include an argyrodite-type compound. The solid electrolyte included in the solid electrolyte layer (300) may be the same as or different from any one of the materials that may be included in the solid electrolyte included in the positive electrode active material layer (120) described above.

[0110] The solid electrolyte contained in the solid electrolyte layer (300) may include a solid electrolyte recovered by the solid electrolyte recovery method described above. For convenience of explanation, the description of the same matters as described above will be omitted below, and the differences will be described in detail.

[0111] The binder in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode coating layer (220).

[0112] The negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode coating layer (220) on the negative electrode current collector (210). The negative electrode current collector (210) may provide a reference surface on which the negative electrode coating layer (220) is disposed. The negative electrode current collector (210) may include, for example, a material that does not react with lithium, i.e., does not form an alloy or a compound with lithium. For example, the negative electrode current collector (210) may include at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector (210) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0113] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) may have, for example, a plate shape or a foil shape. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0114] The negative electrode coating layer (220) can allow lithium metal to grow between it and the negative electrode current collector (210) when the all-solid-state battery is charged. The negative electrode coating layer (220) can act as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0115] The cathode coating layer (220) may include a metal and carbon. For example, the cathode coating layer (220) may include at least one metal selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The cathode coating layer (220) may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the cathode coating layer (220) may include a mixture of carbon black and silver (Ag).

[0116] The cathode coating layer (220) may further include additives other than metal and carbon. The cathode coating layer (220) may further include, for example, at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion conductive additive.

[0117] The negative electrode coating layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode coating layer (220) is too thin, lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210) may cause the negative electrode coating layer (220) to collapse, thereby deteriorating the cycle characteristics of the all-solid-state battery. If the thickness of the cathode coating layer (220) increases excessively, the energy density of the all-solid-state battery may decrease and the internal resistance of the all-solid-state battery due to the cathode coating layer (220) may increase, thereby deteriorating the cycle characteristics of the all-solid-state battery.

[0118] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0119]

[0120] Referring to FIG. 2B, the negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode active material layer (230) disposed on the negative electrode current collector (210). The negative electrode active material layer (230) may include a negative electrode active material and a binder. The negative electrode active material included in the negative electrode active material layer (230) may have a particle form. The median particle size average particle diameter (D50) of the negative electrode active material having a particle form may be, for example, 4 μm or less, 2 μm or less, 1 μm or less, or 900 nm or less. The median particle size average particle diameter (D50) of the negative electrode active material may be, for example, 10 nm to 4 μm, 10 nm to 2 μm, or 10 nm to 900 nm. When the negative electrode active material has a median particle size (D50) within this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. Meanwhile, the median particle size (D50) may be a median diameter measured using a laser particle size distribution meter.

[0121] The negative electrode active material may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0122] The carbon-based negative electrode active material may be amorphous carbon, in particular. Examples of amorphous carbon include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphitic carbon.

[0123] The metal or metalloid negative electrode active material includes, but is not necessarily limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and may be a metal negative electrode active material or a metalloid negative electrode active material that forms an alloy or compound with lithium. On the other hand, nickel (Ni) does not form an alloy with lithium and therefore is not a metal negative electrode active material.

[0124] The negative electrode active material layer (230) includes one type of negative electrode active material among these negative electrode active materials, or includes a mixture of a plurality of different negative electrode active materials. For example, the negative electrode active material layer (230) may include only amorphous carbon, or may include one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn).

[0125] In one embodiment, the negative active material layer (230) may include a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold (Au), etc., may be, for example, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1 by weight, but is not necessarily limited to this range and may be selected according to the characteristics of the required all-solid-state battery. When the negative active material has this composition, the cycle characteristics of the all-solid-state battery can be further improved.

[0126] The binder included in the negative electrode active material layer (230) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto. The binder may include a single binder or a plurality of different binders.

[0127] Since the negative active material layer (230) includes a binder, the negative active material layer (230) can be stably formed on the negative current collector (210). That is, the bonding strength between the negative active material layer (230) and the negative current collector (210) can be increased. In addition, cracking of the negative active material layer (230) is suppressed despite changes in the volume and / or relative positions of the negative active material layer (230) during the charge and discharge process. If the negative active material layer (230) does not include a binder, the negative active material layer (230) can be easily separated from the negative current collector (210). As the negative active material layer (230) is detached from the negative current collector (210), the negative current collector (210) can come into contact with the solid electrolyte layer at the exposed portion, thereby increasing the possibility of a short circuit occurring.

[0128] The negative electrode active material layer (230) is manufactured, for example, by providing a mixture in which the materials constituting the negative electrode active material layer (230) are dispersed onto the negative electrode current collector (210). Since a binder is included in the materials constituting the negative electrode active material layer (230), stable dispersion of the negative electrode active material in the mixture is possible. For example, when applying the mixture onto the negative electrode current collector (210) by screen printing, it is possible to suppress clogging of the screen (e.g., clogging by aggregates of the negative electrode active material) by the binder.

[0129] The negative electrode active material layer (230) may further include other additives in addition to the negative electrode active material and binder. The negative electrode active material layer (230) may further include, for example, fillers, coating agents, dispersants, ion conductive additives, etc.

[0130] The negative active material layer (230) may have a smaller thickness than the positive active material layer (120). The thickness of the negative active material layer (230) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive active material layer (120). The thickness of the negative active material layer (230) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative active material layer (230) is excessively thin, lithium dendrites formed between the negative active material layer (230) and the negative current collector (210) may cause the negative active material layer (230) to collapse, thereby deteriorating the cycle characteristics of the all-solid-state battery. If the thickness of the negative active material layer (230) increases excessively, the energy density of the all-solid-state battery may decrease and the internal resistance of the all-solid-state battery due to the negative active material layer (230) may increase, thereby deteriorating the cycle characteristics of the all-solid-state battery.

[0131] If the thickness of the negative electrode active material layer (230) decreases, the charge capacity of the negative electrode active material layer (230) may also decrease, for example. The charge capacity of the negative electrode active material layer (230) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, or 2% or less than the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (230) is, for example, 0.1% to 50%, 0.1% to 40%, 0.1% to 30%, 0.1% to 20%, 0.1% to 10%, 0.1% to 5%, or 0.1% to 2% than the charge capacity of the positive electrode active material layer (120). If the charge capacity of the negative electrode active material layer (230) is excessively small, the thickness of the negative electrode active material layer (230) becomes very thin, and the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (230) becomes excessively thin may occur. If the charge capacity of the negative electrode active material layer (230) increases excessively, the same defects as the defects described above that occur when the thickness of the negative electrode active material layer (230) increases excessively may occur.

[0132] The charge capacity of the positive electrode active material layer (120) can be obtained by multiplying the charge capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material of the positive electrode active material layer (120). When the positive electrode active material layer (120) includes several types of positive electrode active materials, the [charge capacity density Х mass] value is calculated for each positive electrode active material, and the sum of these values ​​of the positive electrode active materials is the charge capacity of the positive electrode active material layer (120). The charge capacity of the negative electrode active material layer (230) can also be calculated in the same way. That is, the charge capacity of the negative electrode active material layer (230) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer (230). When the negative electrode active material layer (230) includes several types of negative electrode active materials, the [charge capacity density Х mass] value is calculated for each negative electrode active material, and the sum of these values ​​of the negative electrode active materials is the capacity of the negative electrode active material layer (230). Here, the charge capacity density of the positive electrode active material and the negative electrode active material may be an estimated capacity using an all-solid-state half-cell using lithium metal as a counter electrode. The charge capacity of the positive electrode active material layer (120) and the negative electrode active material layer (230) can be directly measured by measuring the charge capacity using the all-solid-state half-cell. The charge capacity density can be obtained by dividing the measured charge capacity by the mass of each active material. Meanwhile, in the present specification, the “charge capacity” of the positive electrode active material layer (120) and the negative electrode active material layer (230) means the initial charge capacity measured at the time of the first cycle charge.

[0133] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the negative active material layer (230) and the solid electrolyte layer (300).

[0134]

[0135] While embodiments of the present invention have been described with reference to the attached drawings, the present invention may be implemented in other specific forms without altering the technical spirit or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Crushing all-solid-state battery waste in a moisture-controlled atmosphere; Dissolving the above-mentioned pulverized result in a polar solvent to prepare a mixture; Filtering the mixture to recover the liquid; Analyzing the components of the recovered liquid and adjusting the liquid to the desired composition ratio; Drying the above adjusted liquid to remove the solvent; and A method for recovering a solid electrolyte, comprising heat-treating a powder from which the solvent has been removed.

2. In paragraph 1, A method for recovering a solid electrolyte, further comprising dismantling an all-solid-state battery pack or module prior to the crushing.

3. In paragraph 1, A method for recovering a solid electrolyte, wherein the above-mentioned all-solid-state battery waste comprises at least one of a cell and process scrap.

4. In paragraph 1, A method for recovering a solid electrolyte, wherein the above moisture control atmosphere is an inert gas atmosphere containing at least one selected from nitrogen, argon, helium, neon, krypton, xenon, and radon.

5. In paragraph 1, A method for recovering a solid electrolyte, wherein the above moisture control atmosphere is a dry room atmosphere.

6. In paragraph 5, A method for recovering a solid electrolyte, wherein the above dry room atmosphere has a relative humidity of 10% or less and a dew point of -10°C or less.

7. In paragraph 1, The above crushing is, A method for recovering a solid electrolyte, comprising using at least one selected from the group consisting of a jaw crusher, a cone crusher, a roll crusher, a hammer mill, a cut mill, a pin mill, an impact mill, a ball mill, and a shredder.

8. In paragraph 1, A method for recovering a solid electrolyte, wherein the polar solvent comprises at least one selected from the group consisting of ethanol, methanol, propanol, butanol, dimethyl carbonate, ethyl acetate, 1,2-dimethoxyethane, propylene glycol dimethyl ether, tetrahydrofuran (THF), and acetonitrile (ACN).

9. In paragraph 1, A method for recovering a solid electrolyte, wherein the above filtering is performed using a decanter (centrifuge), filter or filter press.

10. In paragraph 1, A method for recovering a solid electrolyte, wherein the above filtering comprises centrifuging at 1,000 rpm to 5,000 rpm for 10 to 30 minutes.

11. In paragraph 1, Adjusting the above liquid to the desired composition ratio is as follows: A method for recovering a solid electrolyte, comprising measuring the content of elements constituting the solid electrolyte contained in the above liquid and adding the missing components according to the measurement results.

12. In paragraph 1, Adjusting the above liquid to the desired composition ratio is as follows: A method for recovering a solid electrolyte, comprising adding at least one of a lithium (Li)-containing compound, a phosphorus (P)-containing compound, a sulfur (S)-containing compound, a halogen element-containing compound, and a metal (M)-containing compound to the recovered liquid.

13. In paragraph 1, A method for recovering a solid electrolyte, wherein the solvent is recovered and reused.

14. In paragraph 1, A method for recovering a solid electrolyte, wherein the above heat treatment is performed at a temperature of 400°C to 700°C.

15. In paragraph 1, A method for recovering a solid electrolyte, wherein the heat-treated powder comprises a sulfide-based solid electrolyte.

16. In paragraph 15, The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are positive numbers, Z is one of Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga, In), Li 7-x PS 6-x Clx(0 <x<2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I x A method for recovering a solid electrolyte, wherein at least one is selected from the group consisting of (0≤x≤2).

17. In paragraph 15, The above sulfide-based solid electrolyte is represented by the following chemical formula 1, and a method for recovering a solid electrolyte including an argyrodite-type compound: [Chemical Formula 1] Li 7-a M a PS 6-c X c In the above chemical formula 1, X is F, Br, Cl or a combination thereof, The above M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi) or these. It's a combination, 0≤a≤2, 0≤c≤2.

18. In paragraph 15, A method for recovering a solid electrolyte, wherein the purity of the sulfide-based solid electrolyte in the heat-treated powder is 90% or higher.

19. A solid electrolyte recovered by a method according to any one of claims 1 to 18.

20. Including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, An all-solid-state battery, wherein the solid electrolyte layer comprises the solid electrolyte described in claim 19.

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