Method for manufacturing composite solid electrolytes

Abstract

The present invention relates to a method for producing a composite solid electrolyte having high ionic conductivity, which is capable of being produced in a continuous process and in large scale.

Description

[Technical Field]

[0001] This application claims priority rights under Korean Patent Application No. 10-2022-0066945 dated May 31, 2022, and Korean Patent Application No. 10-2023-0070136 dated May 31, 2023, and incorporates all the contents disclosed in the documents of said Korean patent applications as part of this specification.

[0002] This invention relates to a method for producing a composite solid electrolyte. [Background technology]

[0003] Lithium-ion batteries, which use liquid electrolytes, have a structure in which the negative and positive electrodes are separated by a separator membrane. Therefore, if the separator membrane is damaged due to deformation or external impact, a short circuit can occur, which can lead to dangers such as overheating and explosion. Thus, the development of solid electrolytes that can ensure safety in the field of lithium-ion secondary batteries is a very important issue.

[0004] Lithium-ion batteries using solid electrolytes offer several advantages: increased battery safety, improved reliability due to the prevention of electrolyte leakage, and the ease of manufacturing thin batteries. Furthermore, the use of lithium metal in the negative electrode allows for increased energy density, making them promising for applications in small secondary batteries as well as high-capacity secondary batteries for electric vehicles, and attracting attention as a next-generation battery.

[0005] Among solid electrolytes, polymer solid electrolytes may use polymer materials with ion-conducting properties, or inorganic materials such as oxides or sulfides that have ion-conducting properties. Composite solid electrolytes, which are mixtures of polymer and inorganic materials, have also been proposed.

[0006] Conventional composite solid electrolytes were manufactured by first creating a solution or slurry by mixing and dispersing polymers and inorganic materials, and then performing a solution casting and high-temperature drying process on a substrate. However, conventional manufacturing techniques for composite solid electrolytes have limitations. Because the uniform dispersion of inorganic materials within the polymer solution is not smooth, an uneven distribution of inorganic particles is formed within the composite solid electrolyte, making it difficult to manufacture composite solid electrolytes with improved ionic conductivity.

[0007] To overcome these limitations of conventional composite solid electrolytes, there is a need for technological development of a manufacturing method for composite solid electrolytes that allows for the uniform dispersion of polymers and inorganic materials, thereby improving the ionic conductivity of the composite solid electrolyte, and enabling a continuous process. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Korean Published Patent No. 10-2017-0045011 [Overview of the project] [Problems that the invention aims to solve]

[0009] The object of the present invention is to provide a method for producing a composite solid electrolyte that enables improved ionic conductivity and continuous processing.

[0010] Another object of the present invention is to provide an all-solid-state battery containing a composite solid electrolyte manufactured by the above manufacturing method. [Means for solving the problem]

[0011] In order to achieve the aforementioned objective, The present invention relates to (1) a first step of mixing a first polymer containing a crosslinking functional group with a ceramic compound to produce a first composite layer, (2) A second step of sintering the first composite layer to produce a ceramic ion conductor layer, (3) A third step of manufacturing a second composite layer by coating the ceramic ion conductor layer with a composition containing a second polymer and a lithium salt is included. The method for manufacturing a composite solid electrolyte provided herein includes the first to third steps being performed continuously.

[0012] The present invention also provides a composite solid electrolyte manufactured by the manufacturing method of the present invention, which includes a ceramic ion conductor layer containing a ceramic compound, a second polymer, and a lithium salt.

[0013] The present invention also provides a all-solid-state battery including the composite solid electrolyte manufactured by the manufacturing method of the present invention.

Advantages of the Invention

[0014] The method for manufacturing a composite solid electrolyte according to the present invention can effectively improve the ion conduction of lithium ions by forming a first polymer containing a crosslinkable functional group and a ceramic ion conductor containing a ceramic compound, and can improve the ionic conductivity of the composite solid electrolyte by using the ceramic ion conductor.

[0015] Moreover, the method for manufacturing a composite solid electrolyte according to the present invention can manufacture the composite solid electrolyte in a continuous process and enables mass production.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a flowchart of the method for manufacturing a composite solid electrolyte of the present invention. [Figure 2] FIG. 2 is an image of the first composite layer according to an embodiment of the present invention. [Figure 3] FIG. 3 is an image of a ceramic ion conductor layer formed by sintering the first composite layer according to an embodiment of the present invention. [Figure 4]Figure 4 is a scanning electron microscope (SEM) image of a ceramic compound (Pristine LLZO) powder according to one embodiment of the present invention. [Figure 5] Figure 5 is a scanning electron microscope (SEM) image of a ceramic ion conductor layer according to one embodiment of the present invention. [Figure 6] Figure 6 is an image of the first composite layer according to one embodiment of the present invention. [Figure 7] Figure 7 is an image of a ceramic ion conductor layer according to one embodiment of the present invention. [Figure 8] Figure 8 shows an image of the ceramic ion conductor layer according to Comparative Example 1. [Modes for carrying out the invention]

[0017] The present invention will be described in more detail below to aid in understanding the present invention.

[0018] The terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical spirit of the present invention, based on the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0019] Conventional methods for manufacturing composite solid electrolytes involved coating a substrate film with a solution or slurry containing a mixture of polymers and inorganic materials, using methods such as solution casting, and then drying the film. However, this method had the problem that the ionic conductivity of the solid electrolyte was not improved due to the non-uniform dispersion of inorganic materials within the polymer solution.

[0020] To improve upon this, the present invention aims to provide a method for producing a composite solid electrolyte by forming a first hydrogel-like composite between a first polymer containing crosslinking functional groups and a ceramic compound, sintering this composite, and then coating it with a second polymer and a lithium salt.

[0021] The method for producing the composite solid electrolyte of the present invention allows for the uniform dispersion of the ceramic compound within the first composite, effectively forming an ion conduction path for lithium ions, and obtaining a composite solid electrolyte with improved ionic conductivity. Furthermore, the method for producing the composite solid electrolyte of the present invention can be carried out in a continuous process, enabling mass production.

[0022] Method for manufacturing composite solid electrolytes The present invention relates to a method for producing a composite solid electrolyte, and the method for producing a composite solid electrolyte according to the present invention is: (1) A first step of mixing a first polymer containing crosslinking functional groups with a ceramic compound to produce a first composite layer, (2) A second step of sintering the first composite layer to produce a ceramic ion conductor layer, (3) The third step includes coating the ceramic ion conductor layer with a composition containing a second polymer and a lithium salt to produce a second composite layer.

[0023] The first to third steps described above are performed in a continuous manner.

[0024] The method for producing the composite solid electrolyte involves hydrogelating the first polymer to produce a first composite layer in which ceramic compound particles are uniformly dispersed within the first polymer, and then sintering the first composite layer to efficiently produce a ceramic ion conductor layer, thereby improving the ion conduction of lithium ions and producing a composite solid electrolyte with improved ion conductivity.

[0025] The method for producing the composite solid electrolyte according to the present invention will be described in more detail below, step by step.

[0026] The first step is to produce a first composite layer by mixing a first polymer containing crosslinking functional groups with a ceramic compound.

[0027] The first composite layer is produced by hydrogelation of the first polymer, and is in a form in which particles of the ceramic compound are uniformly dispersed within the hydrogel-like first polymer. The first composite layer includes an amorphous polymer chain containing a crosslinking structure and crosslinking functional groups between the first polymer and the ceramic compound, and the crosslinking structure includes (a) crosslinking between crosslinking functional groups and (b) crosslinking between the crosslinking functional groups and the ceramic compound.

[0028] The cross-linking bonds described in (a) and (b) above are either physical or chemical cross-linking bonds.

[0029] The crosslinking between the crosslinkable functional groups (a) includes hydrogen bonds between the crosslinkable functional groups, for example, the hydrogen bonds are OH - It is a hydrogen bond between them.

[0030] The crosslinking between the crosslinking functional group (b) and the ceramic compound includes bonding by Lewis acid-base interaction, for example, the bonding between the -OH group and Li. The crosslinking between the crosslinking functional group (b) and the ceramic compound is bonding by Lewis acid-base interaction, and is a crosslink in the form of a metal-ligand bond.

[0031] Furthermore, the crosslinking between the (b) crosslinking functional group and the ceramic compound prevents aggregation between the particles of the ceramic compound and ensures that the particles of the ceramic compound are uniformly dispersed within the hydrogel. This is achieved by forming a hydrogel of the first polymer to produce a first composite layer, and then sintering the first composite layer to produce a ceramic ion conductor layer, thereby improving the ionic conductivity of the composite solid electrolyte.

[0032] The aforementioned cross-linking structure improves the mobility of lithium ions within the electrolyte, thereby providing a composite solid electrolyte with improved ionic conductivity.

[0033] In the present invention, the crosslinking functional group contained in the first polymer has the property of being able to form a crosslinked structure by forming bonds as shown in (a) and (b) above.

[0034] For example, the crosslinking functional group may include one or more selected from the group consisting of a hydroxyl group, a carboxyl group, and an amide group.

[0035] Furthermore, the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group is between 80,000 g / mol and 130,000 g / mol, specifically, 80,000 g / mol or more, 83,000 g / mol or more, or 85,000 g / mol or more, and 90,000 g / mol or less, 110,000 g / mol or less, or 130,000 g / mol or less. If the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group is less than 80,000 g / mol, the bonds formed by the crosslinking functional group may not be sufficiently formed to obtain a crosslinked structure. If the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group exceeds 130,000 g / mol, the entanglement of polymer chains increases in the polymer solution used in the manufacturing process, and the solvent penetration rate into the polymer chain decreases. This can accelerate the gelation of the polymer, reduce its solubility, and prevent smooth bonding by crosslinking functional groups, making it difficult to form a crosslinked structure.

[0036] Furthermore, the first polymer containing the crosslinking functional group is made up of polyvinyl alcohol (PVA), gelatin, methylcellulose, agar, dextrin, poly(vinyl pyrrolidone), poly(acrylamide), poly(acrylic acid, PAA), starch-carboxymethylcellulose, hyaluronic acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol. It may include one or more selected from the group consisting of PEG. Preferably, the polymer containing the crosslinking functional group is PVA, which is advantageous in the manufacturing process of the composite solid electrolyte because, during freezing, the phase separation between the PVA and the solvent is efficiently performed, and the crosslinking structure is formed by the (a) and (b) bonds derived from the crosslinking functional group of the PVA that has been phase-separated from the solvent.

[0037] The ceramic compound is an oxide-based or phosphate-based solid electrolyte. The oxide-based or phosphate-based solid electrolyte is a garnet-type lithium-lanthanum-zirconium oxide system (LLZO, Li7La3Zr2O 12 ), perovskite-type lithium-lanthanum-titanium oxide system (LLTO, Li 3x La 2 / 3-x TiO3), phosphate-based NASICON type lithium aluminum-titanium phosphate (LATP, Li 1+x Al x Ti 2-x (PO4)3), Lithium-aluminum-germanium phosphate system (LAGP, Li 1.5 Al0.5 Ge 1.5 (PO4)3), lithium-silicon-titanium phosphate (LSTP, LiSiO2TiO2(PO4)3), and lithium-lanthanum-zirconium-titanium oxide (LLZTO) compounds. Since the oxide-based or phosphate-based solid electrolyte has a very high grain boundary resistance, a sintering process at 1000 °C or higher is required. As a result, there are problems such as lithium volatilization, phase transition, and impurity phase formation at high temperatures. However, the oxide-based or phosphate-based solid electrolyte generally has a maximum ionic conductivity value of 10 -4 ~10 -3 S / cm at room temperature, is stable in the high voltage region, and is stable in air, so it has the advantage of being easy to synthesize and handle.

[0038] Therefore, by mixing the first polymer according to the present invention with a different substance and manufacturing a composite solid electrolyte, the drawbacks of each material can be complemented.

[0039] The oxide-based or phosphate-based solid electrolyte has high thermal stability because it does not easily burn or cause ignition even under high temperature conditions of 400 °C or higher. Therefore, when the ceramic ion conductor contains the oxide-based or phosphate-based solid electrolyte, it can improve not only the mechanical strength of the composite solid electrolyte for lithium secondary batteries but also the thermal stability and ionic conductivity.

[0040] Also, the first step is (1-1) manufacturing a composition for forming a first composite containing a first polymer having a cross-linkable functional group and a ceramic compound; (1-2) unwinding the base film using an unwinder and supplying it to the conveying path; (1-3) coating the composition for forming the first composite on the base film to form a coating film; (1-4) conveying the base film on which the coating film is formed to the freezing section and freezing the coating film; (1-5) A step of transporting the substrate film on which the frozen coating film is formed to a thawing section to thaw the frozen coating film and to form a physical crosslink bond between the first polymer and the ceramic compound to produce the first composite layer, and (1-6) The process includes winding and recovering the substrate film containing the first composite layer using a rewinder.

[0041] Step (1-1) is a step of producing a first composite-forming composition comprising a first polymer containing a crosslinking functional group and a ceramic compound.

[0042] The first composite-forming composition is prepared by adding a ceramic compound to a first polymer solution containing crosslinking functional groups.

[0043] The solvent used in the production of the first polymer solution is a polar solvent, such as water. In other words, the first polymer solution is an aqueous solution.

[0044] The concentration of the first polymer solution containing the crosslinking functional group can be appropriately adjusted to ensure that the coating process proceeds smoothly when applying the first composite-forming solution to the substrate film. For example, the first polymer containing the crosslinking functional group is present in an amount of 5 to 20% by weight relative to the total weight of the aqueous solution of the first polymer containing the crosslinking functional group. Specifically, this amount is 5% or more by weight, 7% or more by weight, or 9% or more by weight, and 13% or less by weight, 17% or less by weight, or 20% or less by weight. If the amount of the first polymer containing the crosslinking functional group is less than 5% by weight, the concentration is excessively dilute and may run off when applied to the substrate film. If it exceeds 20% by weight, it may be difficult to apply it in a uniform thin film.

[0045] Furthermore, the ceramic compound is contained in an amount of 1 part by weight or more and less than 10 parts by weight per 1 part by weight of the first polymer containing the crosslinking functional group. More specifically, the weight ratio of the first polymer to the ceramic compound may be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, or 1:9. If the ceramic compound is contained in an amount of less than 1 part by weight per 1 part by weight of the first polymer, the bonding between the ceramic compounds will not proceed smoothly after the sintering process in step (2) below, making it difficult to form a crosslinked ceramic ion conductor. In addition, the mechanical properties will be weak, so it will easily break or shatter, and there will be problems in manufacturing the composite solid electrolyte. Furthermore, if the ceramic compound is present in amounts exceeding 10 parts by weight per 1 part by weight of the first polymer, the ceramic compound will not be uniformly dispersed within the first polymer, causing the ceramic compound particles to aggregate. This leads to phase separation between the first polymer and the aggregated ceramic compound particles, making it difficult to form a ceramic ion conductor layer. As a result, a composite solid electrolyte with reduced ionic conductivity is produced.

[0046] The above steps (1-2) involve unwinding the base film using an unwinder and supplying it to the transport path.

[0047] The unwinder winds the base film, which is wound in a roll shape, onto a predetermined transport path and supplies it. It can unwind and supply the base film by its own drive, and it can also unwind and supply the base film by the driving force of a rewinder that winds the base film containing the first composite.

[0048] Therefore, the first step of the present invention can be a roll-to-roll step.

[0049] The base film is not particularly limited as long as it can serve as a support to which the first composite-forming composition is applied. For example, the base film may be stainless steel (SS), polyethylene terephthalate film, polytetrafluoroethylene film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, vinyl chloride copolymer film, polyurethane film, ethylene-vinyl acetate film, ethylene-propylene copolymer film, ethylene-ethyl acrylate copolymer film, ethylene-methyl acrylate copolymer film, or polyimide film.

[0050] The steps (1-3) above are steps of applying the first composite-forming composition onto the base film to form a coated film.

[0051] The coating method in the present invention is not particularly limited as long as it is a method that can coat the first composite-forming composition in a film-like manner onto the substrate film. For example, the coating method may be bar coating, roll coating, spin coating, slit coating, die coating, blade coating, comma coating, slot die coating, lip coating, spray coating, or solution casting.

[0052] As one specific embodiment of the present invention, a solution casting method can be used. More specifically, after placing the first composite-forming composition manufactured in step (1-1) into a mixer, the mixer can be positioned on a substrate film and the first composite-forming composition can be continuously cast onto the substrate film supplied to the transport path to form a coated film.

[0053] Steps (1-4) above involve transporting the substrate film on which the coating film is formed to a freezing section to freeze the coating film, and the first composite layer can be manufactured in step (1-4).

[0054] In steps (1-4) above, the first polymer and water in the aqueous solution of the first polymer containing the crosslinking functional group may undergo phase separation. This phase separation can be induced because the hydrogen bonds between water molecules are stronger than the hydrogen bonds between the crosslinking functional group and water molecules. The water molecules aggregated by the hydrogen bonds between water molecules exist as an ice state (ice phase) during the freezing process. As a result, the number of crosslinking functional groups that form hydrogen bonds through interaction with water molecules is significantly reduced.

[0055] As a result of the phase separation, the interior of the coated film is divided into (i) a polymer-poor phase and (ii) a polymer-rich phase.

[0056] The aforementioned (i) Polymer-poor phase is a region containing water molecules aggregated by hydrogen bonds between water molecules, existing in an ice state (ice phase), which can also be described as a free water state.

[0057] The (ii) Polymer-rich phase is a portion containing a polymer that has been phase-separated from water. The phase-separated polymer contains crosslinking functional groups that are free from interaction with water molecules. After phase separation, it becomes free and does not form crystals through regular folding, but exists in a relatively free amorphous state, which is called an amorphous polymer chain.

[0058] Furthermore, some of the crosslinking functional groups contained in the phase-separated polymer form localized crystallites. These localized crystallites act as crosslinkable junction points, forming a crosslinked structure that includes the (a) and (b) bonds.

[0059] The freezing of the coated film in steps (1-4) above can be carried out by appropriately selecting conditions that allow the coated film to freeze sufficiently. For example, the freezing temperature can be -30°C to -10°C, specifically -30°C or higher, -25°C or higher, or -23°C or higher, and -18°C or lower, -15°C or lower, or -10°C or lower. If the freezing temperature is below -30°C, cracks may occur in the coated film, and if it is above -10°C, phase separation between the polymer and water may not occur sufficiently, making it difficult to form amorphous polymer chain regions. Furthermore, the freezing should be carried out within a range of 20 to 30 hours, taking into consideration the time required for sufficient freezing.

[0060] The aforementioned freezing section is located in the section where a coating film is formed on a base film and the base film on which the coating film is formed is transported to a rewinder, and is composed of multiple units.

[0061] Steps (1-5) above involve transporting the substrate film on which the frozen coating film is formed to the thawing section to thaw the frozen coating film and produce the first composite layer.

[0062] In the steps described in (1-5) above, the ice contained in the (i) Polymer-poor phase melts and evaporates, thereby enabling the production of a first composite layer with increased free volume.

[0063] The thawing process can be carried out by appropriately selecting conditions that allow the frozen coating film to thaw sufficiently for application with a polymer solid electrolyte. For example, the thawing temperature can be 15°C to 35°C, or room temperature (25°C). If the thawing temperature is below 15°C, the moisture drying efficiency after thawing (ice melting) may decrease, and if it exceeds 35°C, the coating film may shrink, causing wrinkles or warping.

[0064] As described above, through the steps of freezing the coating film (1-4) and thawing the frozen coating film (1-5), the defect freezing described in (a) and (b) is induced, forming a crosslinked structure and amorphous polymer chains.

[0065] Therefore, steps (1-4) and (1-5) can be repeated, and the degree of cross-linking structure formation can be adjusted by the number of repetitions. When steps (1-4) and (1-5) constitute one cycle, step (1-4) of freezing the coated film and step (1-5) of thawing the frozen coated film can be performed for one or more cycles, two or more cycles, three or more cycles, or five or more cycles. The upper limit of the cycles is not particularly limited, but is 10 cycles or less, 13 cycles or less, or 15 cycles or less. Within the above range, the more cycles are performed, the more cross-linking structures are formed, thereby increasing the modulus and strength of the polymer solid electrolyte.

[0066] Once thawing is complete in step (1-5) above, the coated film can be applied as the first composite layer.

[0067] The aforementioned thawing section is located within the section in which the substrate film on which the frozen coating film is formed is transported to the rewinder, and consists of multiple units.

[0068] Furthermore, a chemical cross-linker can be added to the first composite-forming composition in step (1-1), and the chemical cross-linker forms a cross-linked bonding structure between the first polymer and the ceramic compound in step (1-4).

[0069] In the first composite layer, crosslinked structures and amorphous polymer chains are formed by physical crosslinking during the freezing process in steps (1-4). As described above, if a chemical crosslinking agent is added in step (1-1), the crosslinked structures may also be formed by chemical crosslinking.

[0070] Specifically, the aforementioned chemical crosslinking agent may form crosslinks between the first polymer containing crosslinking functional groups and the ceramic compound, thereby forming a crosslinked structure.

[0071] The chemical crosslinking agent can form bonds between first polymers containing crosslinking functional groups, or between the first polymer containing the crosslinking functional groups and the ceramic compound.

[0072] The aforementioned chemical crosslinking agent may include one or more selected from the group consisting of boric acid, glutaraldehyde, inorganic salts, and metal salts, but is not limited to these examples; any chemical crosslinking agent that forms the hydrogel of the first polymer is acceptable.

[0073] Steps (1-6) above are steps in which the base film containing the first composite layer is wound up and recovered using a rewinder.

[0074] The rewinder can recover the base film containing the first composite layer by winding it into a roll, and can wind up the base film containing the first composite layer by its own drive.

[0075] In the present invention's method for manufacturing a composite solid electrolyte, the first step is a roll-to-roll process, enabling continuous manufacturing.

[0076] The second step can be carried out immediately after the above steps (1-6). The second step is, (2-1) Using an unwinder, the base film containing the first composite layer is unwound, the first composite layer is peeled from the base film and slit, and (2-2) The step of sintering the substrate film containing the slit first composite layer to produce a ceramic ion conductor layer.

[0077] The (2-1) step involves unwinding the base film containing the first composite layer using an unwinder, peeling the first composite layer from the base film, and slitting it.

[0078] The unwinder winds a base film containing the first composite layer, which is wound in a roll shape, onto a predetermined transport path and supplies it. It can also unwind and supply the base film containing the first composite layer by its own drive.

[0079] After that, the first composite layer is peeled off from the base film, and then slitting is performed on the desired area.

[0080] The (2-2) step is a step of manufacturing a ceramic ion conductor layer by sintering the slit first composite layer.

[0081] Here, sintering refers to the process of applying sufficient temperature and pressure to make the first composite layer a harder aggregate of particles.

[0082] The ceramic ion conductor is manufactured by sintering the first composite layer to cause thermal decomposition, and then sintering the remaining ceramic compound particles.

[0083] After the sintering process, the first polymer acts as a support so that the ceramic compound particles can connect to one another, and the ceramic compound particles are connected to each other, forming a ceramic ion conductor layer having a single cross-linked bonding structure.

[0084] The ceramic ion conductor layer includes a cross-linked bonding structure containing a ceramic compound.

[0085] The ceramic ion conductor layer plays a role in forming an ion conduction path for lithium ions.

[0086] The sintering can be carried out by appropriately selecting conditions that allow the first composite layer to be thermally decomposed and the particle structures of the ceramic compound to link together to form a cross-linked ceramic ion conductor layer. For example, the sintering temperature can be 800°C to 1300°C, specifically, 850°C or higher, 900°C or higher, 950°C or higher, 1300°C or lower, 1250°C or lower, and 1200°C or lower.

[0087] A third step may be carried out immediately after the above step (2-2). The third step is, (3-1) A step of producing a composition containing the second polymer and a lithium salt, (3-2) The step of coating the ceramic ion conductor layer with the composition, and (3-3) The step of drying the ceramic ion conductor layer coated with the composition to form a second composite layer.

[0088] By including the ceramic ion conductor layer in the second composite layer, a composite solid electrolyte with improved ionic conductivity can be manufactured.

[0089] The (3-1) step is a step of producing a composition containing the second polymer and the lithium salt.

[0090] The second polymer exhibits excellent solubility of lithium salts, and its polymer solution penetrates well into the ceramic ion conductor, making it easy to manufacture the final composite solid electrolyte. Specific examples of the second polymer include one or more selected from the group consisting of polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylate, poly(methyl methacrylate, PMMA), PSTFSI, polyurethane, nylon, poly(dimethylsiloxane), gelatin, methylcellulose, agar, dextrin, poly(vinyl pyrrolidone), poly(acrylamide), poly(acrylic acid), starch-carboxymethylcellulose, hyaluronic acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol (PEG).

[0091] In the present invention, the lithium salt is contained in a dissociated state within the structure formed by the ceramic ion conductor layer, thereby improving the ionic conductivity of the composite solid electrolyte. Furthermore, the lithium salt is mainly dissociated within the second polymer, and plays a role in compensating for the loss of lithium ions generated from the ceramic compound particles during the high-temperature sintering process in the second step.

[0092] The aforementioned lithium salts are LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10It includes one or more selected from the group consisting of LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, LiC(CF3SO2)3, (CF3SO2)2NLi, and (FSO2)2NLi.

[0093] The above composition is produced by adding a lithium salt to a solution containing the second polymer.

[0094] The solvent used in the production of the second polymer solution is a polar solvent, such as water. In other words, the second polymer solution is an aqueous polymer solution.

[0095] The concentration of the solution containing the second polymer can be appropriately adjusted to allow the coating process for coating the ceramic ion conductor layer to proceed smoothly. For example, the second polymer is present in an amount of 5 to 20% by weight relative to the total weight of the second polymer solution, specifically 5% or more by weight, 7% or more by weight, or 9% or more by weight, and 13% or less by weight, 17% or less by weight, or 20% or less by weight. If the second polymer is present in an amount of less than 5% by weight, the concentration is excessively dilute and it is not possible to coat the surface of the ceramic ion conductor layer. If it is present in an amount exceeding 20% ​​by weight, the concentration becomes excessively high and it is difficult to uniformly coat the surface of the ceramic ion conductor layer.

[0096] The molar ratio ([Li] / [G]) of the second polymer to the lithium ([Li]) of the lithium salt is 0.1 to 0.5, specifically 0.1 or more, 0.2 or more, or 0.3 or more, and 0.4 or less, or 0.5 or less. If the molar ratio ([Li] / [G]) is less than 0.1, the lithium salt content decreases, which may reduce the ionic conductivity of the composite solid electrolyte. If the molar ratio ([Li] / [G]) exceeds 0.5, the ionic conductivity may decrease due to the aggregation of lithium ions. Therefore, the composite solid electrolyte according to the present invention requires the second polymer and an appropriate amount of lithium salt in the second composite layer.

[0097] The (3-2) step is the step of coating the ceramic ion conductor layer with the composition.

[0098] The method of coating is not particularly limited as long as it is used in the industry, and methods such as dipping, spraying, doctor blade coating, or spin coating can be used, with dipping being preferred.

[0099] Step (3-3) above is the step of drying the ceramic ion conductor layer coated with the composition to form a second composite.

[0100] The drying can be carried out in an oven, and the drying temperature is not particularly limited as long as it is a temperature that can dry the composition, but is preferably 80 to 100°C.

[0101] Furthermore, the coating process described in (3-2) and the drying process described in (3-3) can be repeated multiple times.

[0102] The ceramic ion conductor layer coated with the second composite layer is a composite solid electrolyte to be manufactured in the present invention, and the composite solid electrolyte has improved ionic conductivity, specifically 10 -5 It exhibits an ionic conductivity of S / cm or higher. Despite being a solid electrolyte, the composite solid electrolyte exhibits an ionic conductivity at a level equivalent to or higher than that of conventional liquid electrolytes, thereby improving the performance of all-solid-state batteries.

[0103] The method for producing the composite solid electrolyte of the present invention is a continuous process in which the first to third steps are carried out in succession, and mass production is possible.

[0104] Composite solid electrolyte Furthermore, the present invention relates to a composite solid electrolyte comprising a conductive layer containing a ceramic compound, a second polymer, and a lithium salt, wherein the composite solid electrolyte is manufactured by the manufacturing method of the present invention described above.

[0105] The ceramic ion conductor layer, the second polymer, and the lithium salt are as described above.

[0106] The ceramic ion conductor layer is obtained by sintering the first composite layer described above. Therefore, the ceramic ion conductor layer includes a crosslinking structure between the first polymer containing crosslinking functional groups and the ceramic compound.

[0107] Conventional composite solid electrolytes were manufactured by coating a substrate with a solution or slurry containing a mixture of polymers and inorganic materials, and then drying it using methods such as solution casting. However, this method had the problem that the ionic conductivity of the solid electrolyte was not improved due to the non-uniform dispersion and precipitation of inorganic materials in the polymer solution.

[0108] To improve this, the present invention aims to provide a composite solid electrolyte comprising a ceramic ion conductor layer including a cross-linking structure that forms an ion conduction pathway for lithium ions, a second polymer, and a lithium salt. The ceramic ion conductor has ceramic compound particles uniformly dispersed inside it and can play a role in improving the ionic conductivity of the composite solid electrolyte.

[0109] The composite solid electrolyte is in the form of a free-standing film. A free-standing film is a film that can maintain its film form on its own at room temperature and pressure without the need for a separate support.

[0110] The aforementioned freestanding film exhibits elasticity, minimizes brittleness, and possesses the properties of a support that stably contains lithium ions, making it a suitable form for a composite solid electrolyte.

[0111] In the present invention, the ionic conductivity of the composite solid electrolyte is 10 -5 It is S / cm or higher.

[0112] Despite being a solid electrolyte, the aforementioned composite solid electrolyte exhibits ionic conductivity at a level equivalent to or higher than that of conventional liquid electrolytes, thereby improving the performance of all-solid-state batteries.

[0113] All solid state battery Furthermore, the present invention relates to an all-solid-state battery comprising the composite solid electrolyte, wherein the all-solid-state battery comprises a negative electrode, a positive electrode, and a composite solid electrolyte interposed between the negative electrode and the positive electrode, the composite solid electrolyte is manufactured by the manufacturing method described above, and has the aforementioned characteristics.

[0114] Specifically, the composite solid electrolyte contains a ceramic ion conductor, which improves lithium ion conductivity, making it suitable as an electrolyte for all-solid-state batteries.

[0115] In the present invention, the positive electrode included in the all-solid-state battery includes a positive electrode active material layer, and the positive electrode active material layer may be formed on one surface of the positive electrode current collector.

[0116] The positive electrode active material layer comprises a positive electrode active material, a binder, and a conductive material.

[0117] Furthermore, the positive electrode active material is not particularly limited as long as it is a material capable of reversibly intercalating and releasing lithium ions, for example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), Li[Ni x Co y Mn z M v ]O2(In the above formula, M is one element selected from the group consisting of Al, Ga, and In, or two or more elements from these, and 0.3≦x<1.0, 0≦y, z≦0.5, 0≦v≦0.1, x+y+z+v=1), Li(Li a M b-a-b’ M' b’ )O 2-c A cLayered compounds such as (wherein the above formula, 0≦a≦0.2, 0.6≦b≦1, 0≦b'≦0.2, 0≦c≦0.2, M includes Mn and one or more selected from the group consisting of Ni, Co, Fe, Cr, V, Cu, Zn, and Ti, M' is one or more selected from the group consisting of Al, Mg, and B, and A is one or more selected from the group consisting of P, F, S, and N), or compounds substituted with one or more transition metals, chemical formula Li 1+y Mn 2-y Lithium manganese oxides such as O4 (where y is 0 - 0.33), LiMnO3, LiMn2O3, LiMnO2, lithium copper oxide (Li2CuO2), vanadium oxides such as LiV3O8, LiFe3O4, V2O5, Cu2V2O7, and LiNi 1-y Lithium nickel oxide of the Ni site type, represented as MyO2 (where M = Co, Mn, Al, Cu, Fe, Fe, Mg, B, or Ga, and y = 0.01 - 0.3), has the chemical formula LiMn 2-y M y Examples include, but are not limited to, lithium manganese composite oxides represented as O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and y = 0.01 - 0.1) or Li2Mn3MO8 (where M = Fe, Co, Co, Ni, Cu, or Zn), LiMn2O4 in which part of the Li in the chemical formula is substituted with alkali metal ions, disulfide compounds, and Fe2(MoO4)3.

[0118] Furthermore, the positive electrode active material is present in an amount of 40 to 80% by weight, based on the total weight of the positive electrode active material layer. Specifically, the content of the positive electrode active material is 40% or more by weight or 50% or more by weight, and 70% or less by weight or 80% or less by weight. If the content of the positive electrode active material is less than 40% by weight, the connectivity between the wet positive electrode active material layer and the dry positive electrode active material layer may be insufficient, and if it exceeds 80% by weight, the mass transfer resistance may increase.

[0119] Furthermore, the binder contains components that assist in the bonding of the positive electrode active material to conductive materials and to the current collector, such as styrene-butadiene rubber, acrylic styrene-butadiene rubber, acrylonitrile copolymer, acrylonitrile-butadiene rubber, nitrile-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene / propylene copolymer, polybutadiene, oxidized polyethylene, chlorosulfonated polyethylene, polyvinylpyrrolidone, polyvinylpyridine, polyvinyl alcohol, polyvinyl acetate, polyvinyl chloride, polyphosphazene, and polyacrylonitrile. The binder may include one or more selected from the group consisting of tolyl, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethylcellulose, hydroxypropylcellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylcellulose, cyanoethyl scrophularis, polyester, polyamide, polyether, polyimide, polycarboxylate, polycarboxylic acid, polyacrylic acid, polyacrylate, lithium polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyurethane, polyvinylidene fluoride, and poly(vinylidene fluoride)-hexafluoropropene. Preferably, the binder may include one or more selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethylcellulose, polyacrylic acid, lithium polyacrylate, and polyvinylidene fluoride.

[0120] Furthermore, the binder is contained in an amount of 1% to 30% by weight based on the total weight of the positive electrode active material layer. Specifically, the binder content is 1% or more by weight, or 3% or more by weight, and 15% or less by weight, or 30% or less by weight. If the binder content is less than 1% by weight, the adhesion between the positive electrode active material and the positive electrode current collector may decrease. If it exceeds 30% by weight, the adhesion improves, but the amount of positive electrode active material decreases accordingly, which may reduce the battery capacity.

[0121] Furthermore, the conductive material is not particularly limited as long as it prevents side reactions in the internal environment of the all-solid-state battery and has excellent electrical conductivity without causing chemical changes to the battery. Typically, graphite or conductive carbon can be used, and for example, graphite such as natural graphite or artificial graphite, carbon black such as carbon black, acetylene black, Ketjen black, Denka black, thermal black, channel black, furnace black, lamp black, and summer black, carbon-based materials whose crystalline structure is graphene or graphite, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride, aluminum powder, and nickel powder, conductive whiskey such as zinc oxide and potassium titanate, conductive oxides such as titanium oxide, and conductive polymers such as polyphenylene derivatives can be used alone or in mixtures of two or more, but are not limited to these.

[0122] The conductive material is typically present in an amount of 0.5% to 30% by weight based on the total weight of the positive electrode active material layer. Specifically, the content of the conductive material is 0.5% or more by weight, or 1% or more by weight, and 20% or less by weight, or 30% or less by weight. If the content of the conductive material is too low (less than 0.5% by weight), it is difficult to expect an improvement in electrical conductivity, and the electrochemical properties of the battery may deteriorate. If it is too high (more than 30% by weight), the amount of positive electrode active material will be relatively small, and the capacity and energy density may decrease. The method for incorporating the conductive material into the positive electrode is not significantly limited, and conventional methods known in the art, such as coating the positive electrode active material, can be used.

[0123] Furthermore, the positive electrode current collector supports the positive electrode active material layer and plays a role in transferring electrons between the external conductor and the positive electrode active material layer.

[0124] The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the all-solid-state battery and has high electronic conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, silver, etc., and aluminum-cadmium alloys can be used as the positive electrode current collector.

[0125] The positive electrode current collector may have a fine uneven surface or a three-dimensional porous structure to enhance the bonding force with the positive electrode active material layer. As a result, the positive electrode current collector can take various forms, such as film, sheet, foil, mesh, net, porous material, foam, and nonwoven fabric.

[0126] The positive electrode described above can be manufactured according to conventional methods. Specifically, it can be manufactured by mixing a positive electrode active material, a conductive material, and a binder in an organic solvent to produce a composition for forming a positive electrode active material layer, which is then coated onto a positive electrode current collector and dried, and then selectively compress-molded onto the current collector to improve electrode density. In this case, it is preferable to use an organic solvent that can uniformly disperse the positive electrode active material, binder, and conductive material and evaporates easily. Examples include acetonitrile, methanol, ethanol, tetrahydrofuran, water, and isopropyl alcohol.

[0127] In the present invention, the negative electrode included in the all-solid-state battery includes a negative electrode active material layer, and the negative electrode active material layer is formed on one surface of the negative electrode current collector.

[0128] The aforementioned negative electrode active material is lithium ion (Li + This includes materials that can be reversibly intercalated or deintercalated, materials that can react with lithium ions to reversibly form lithium-containing compounds, lithium metals, or lithium alloys.

[0129] The aforementioned lithium ion (Li +A substance that can reversibly insert or remove lithium ions (Li) is, for example, crystalline carbon, amorphous carbon, or a mixture thereof. + Substances that can reversibly form lithium-containing compounds by reacting with ) include, for example, tin oxide, titanates, or silicon. The lithium alloy is, for example, an alloy of lithium (Li) and a metal selected from the group consisting of sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), aluminum (Al), and tin (Sn).

[0130] Preferably, the negative electrode active material is a lithium metal, specifically in the form of a lithium metal thin film or lithium metal powder.

[0131] The negative electrode active material may be present in an amount of 40 to 80% by weight, based on the total weight of the negative electrode active material layer. Specifically, the content of the negative electrode active material may be 40% or more by weight, or 50% or more by weight, and 70% or less by weight, or 80% or less by weight. If the content of the negative electrode active material is less than 40% by weight, the connectivity between the wet negative electrode active material layer and the dry negative electrode active material layer may be insufficient, and if it exceeds 80% by weight, the mass transfer resistance may increase.

[0132] Furthermore, the binder is as described above in the positive electrode active material layer.

[0133] Furthermore, the conductive material is as described above in the positive electrode active material layer.

[0134] Furthermore, the negative electrode current collector is not particularly limited as long as it does not cause a chemical change in the battery and is conductive. For example, the negative electrode current collector can be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., or aluminum-cadmium alloy. Also, similar to the positive electrode current collector, the negative electrode current collector can be made of various forms such as films, sheets, foils, nets, porous materials, foams, or nonwoven fabrics with fine irregularities formed on their surface.

[0135] The method for manufacturing the negative electrode is not particularly limited, and it can be manufactured by forming a negative electrode active material layer on a negative electrode current collector using methods for forming layers or films commonly used in the industry. For example, methods such as crimping, coating, and vapor deposition can be used. Furthermore, the negative electrode of the present invention is also included in the case where a metallic lithium thin film is formed on a metal plate by initial charging after the battery has been assembled without a lithium thin film on the negative electrode current collector.

[0136] Furthermore, the present invention provides a battery module including the all-solid-state battery as a unit battery, a battery pack including the battery module, and a device including the battery pack as a power source.

[0137] Specific examples of the aforementioned devices include, but are not limited to, power tools powered by electric motors, electric vehicles (EVs), electric vehicles including hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters, electric golf carts, and power storage systems.

[0138] The following examples illustrate the present invention, but it will be apparent to those skilled in the art that various changes and modifications are possible within the scope of the category and technical concept of the present invention, and that these changes and modifications will naturally fall within the scope of the appended claims.

[0139] In the examples and comparative examples described below, ceramic ion conductors containing the first polymer and ceramic compounds listed in Table 1 below were manufactured, and composite solid electrolytes containing these were produced.

[0140] [Table 1]

[0141] Examples Example 1: Production of a composite solid electrolyte (1) Manufacturing of the first composite layer A 10 wt% aqueous solution of PVA (Mw: 89,000 g / mol, degree of hydrolysis: > 99%) was mixed with distilled water (DI water). A solution containing LLZO powder, a ceramic compound, was then prepared in the same PVA aqueous solution. The weight ratio of PVA to LLZO was set to 1:2.

[0142] After the solution was placed in a mixer, it was coated onto an SS foil base film supplied to the transport path by an unwinder using a solution casting method. This was then transported to a freezing section and frozen at -20°C for 24 hours, and then transported to a thawing section and thawed at 25°C to induce physical crosslinking of the PVA, thereby producing a first composite layer on the base film. The base film containing the produced first composite layer was wound up and recovered using a rewinder. Subsequently, the base film was peeled off to obtain a hydrogel-like first composite layer.

[0143] (2) Manufacturing of ceramic ion conductor layer After peeling the first composite layer from the substrate film containing the first composite layer supplied to the transport path by an unwinder, the peeled first composite layer was slit to a desired size. The slit first composite layer was heated from room temperature to 800°C at a rate of 1°C / min and sintered at 800°C for 2 hours to thermally decompose the PVA hydrogel contained in the first composite layer, and a ceramic ion conductor layer was produced by sintering the remaining LLZO particles.

[0144] (3) Manufacturing of complex solid electrolytes A solution containing PEO and LiTFSI was prepared (where the molar ratio of "O" in PEO and "Li" in the lithium salt ([Li] / [O]) is 0.4). The ceramic ion conductor layer was immersed in the prepared solution for 5 minutes, and then dried in a vacuum drying oven at 100°C for 12 hours to produce a composite solid electrolyte.

[0145] Example 2 A composite solid electrolyte was prepared in the same manner as in Example 1, except that LSTP was used instead of the ceramic compound LLZO.

[0146] Example 3 A composite solid electrolyte was prepared in the same manner as in Example 1, except that the weight ratio of the polymer (PVA) and the ceramic compound (LLZO) was 1:10.

[0147] Example 4 A composite solid electrolyte was prepared in the same manner as in Example 1, except that the weight ratio of the polymer (PVA) and the ceramic compound (LLZO) was 10:1.

[0148] Example 5 A composite solid electrolyte was produced in the same manner as in Example 1, except that instead of a freezing and thawing step, 0.1 mL of boric acid (1 wt% aqueous solution) was added as a chemical cross-linker to 20 mL of a solution containing the polymer (PVA) and ceramic compound, and the mixture was stirred with a magnetic stirrer at 200 rpm / hour to produce a hydrogel-like first composite layer by chemical cross-linking.

[0149] Example 6 A composite solid electrolyte was prepared in the same manner as in Example 5, except that the weight ratio of the polymer (PVA) and the ceramic compound (LLZO) was 1:10.

[0150] Example 7 A composite solid electrolyte was prepared in the same manner as in Example 5, except that the weight ratio of the polymer (PVA) and the ceramic compound (LLZO) was 10:1.

[0151] Comparative Example 1 A composite solid electrolyte was produced in the same manner as in Example 1, except that a solution containing a polymer (PVA) and a ceramic compound (LLZO) was prepared, the solution was applied to a glass slide which served as a substrate, and then dried at 80°C for 12 hours instead of the freezing and thawing steps.

[0152] Comparative Example 2 A composite solid electrolyte was prepared in the same manner as in Example 1, except that PEO (Mw: 4,000,000,000 g / mol), a polymer without crosslinking functional groups, was used instead of the polymer (PVA).

[0153] Comparative Example 3 A composite solid electrolyte was prepared in the same manner as in Example 1, except that a 35% aqueous solution of poly(acrylic acid) (Mw: 100,000 g / mol) was used instead of the polymer (PVA).

[0154] Experimental Example 1 To measure the ionic conductivity of the film-like composite solid electrolytes produced in the examples and comparative examples, 1.7671 cm² was used. 2 The composite solid electrolyte was punched out in a circular shape, and the punched-out composite solid electrolyte was placed between two sheets of stainless steel (SS) to manufacture a coin cell.

[0155] The resistance was measured using an electrochemical impedance spectrometer (EIS, VM3, Bio Logic Science Instrument) at 25°C with an amplitude of 10 mV and a scan range of 500 kHz to 20 MHz. The ionic conductivity of the composite solid electrolyte was then calculated using Equation 1 shown below.

[0156]

number

[0157] In Equation 1 above, σi is the ionic conductivity of the composite solid electrolyte (S / cm), R is the resistance of the composite solid electrolyte measured by the electrochemical impedance stetrometer (Ω), L is the thickness of the composite solid electrolyte (μm), and A is the area of ​​the composite solid electrolyte (cm²). 2 ) means.

[0158] The ionic conductivity of the composite solid electrolyte calculated using Equation 1, the presence or absence of hydrogel formation, the possibility of freestanding film formation, and the results of observing the appearance of the composite solid electrolyte are shown in Table 2 below. At this time, the presence or absence of hydrogel formation (formed: ○, not formed: X), the possibility of freestanding film formation (formed: ○, not formed: X), and the appearance of the composite solid electrolyte were observed with the naked eye.

[0159] [Table 2]

[0160] As shown in Table 2 above, it was confirmed that a first composite layer can be formed by applying a freezing and thawing process to a solution obtained by mixing the first polymer containing the crosslinking functional group and a ceramic compound in an appropriate weight ratio, and that a ceramic ion conductor layer can be formed by sintering the first composite layer to produce a composite solid electrolyte (Examples 1, 2 and 5 (Figures 2 to 7)).

[0161] Comparative Example 1 was an electrolyte manufactured using a high-temperature drying process at 80°C. It formed a film with weak mechanical properties and no cross-linking structure, and no ceramic ion conductor was formed after sintering.

[0162] Comparative Examples 2 and 3 were prepared using polymers that did not contain crosslinking functional groups, and a hydrogel-like first composite layer was not formed.

[0163] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical concept of the present invention and the claims described below by persons with ordinary skill in the art to which the present invention belongs.

Claims

1. (1) A first step of mixing a first polymer containing crosslinking functional groups and a ceramic compound to produce a first composite layer, (2) A second step of sintering the first composite layer to produce a ceramic ion conductor layer, (3) A third step of manufacturing a second composite layer by coating the ceramic ion conductor layer with a composition containing a second polymer and a lithium salt, The first step includes freezing a coated film to which a first composite-forming composition comprising a first polymer containing a crosslinking functional group and a ceramic compound has been applied, the freezing temperature being -30°C to -10°C. A method for producing a composite solid electrolyte, wherein the first to third steps are carried out in succession.

2. The method for producing a composite solid electrolyte according to claim 1, wherein the crosslinking functional group comprises one or more selected from the group consisting of a hydroxyl group, a carboxyl group, and an amide group.

3. The first polymer containing the crosslinking functional group is polyvinyl alcohol (PVA), gelatin, methylcellulose, agar, dextrin, poly(vinylpyrrolidone), poly(acrylamide), starch-carboxymethylcellulose, hyaluronic acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol. A method for producing a composite solid electrolyte according to claim 1, comprising one or more selected from the group consisting of PEG.

4. The method for producing a composite solid electrolyte according to claim 1, wherein the ceramic compound comprises one or more selected from the group consisting of lithium-lanthanum-zirconium oxide (LLZO), lithium-silicon-titanium phosphate (LSTP), lithium-lanthanum-titanium oxide (LLTO), lithium-aluminum-titanium phosphate (LATP), lithium-aluminum-germanium phosphate (LAGP), and lithium-lanthanum-zirconium-titanium oxide (LLZTO) compounds.

5. The method for producing a composite solid electrolyte according to claim 1, wherein the ceramic compound is contained in an amount of 1 part by weight or more and less than 10 parts by weight per 1 part by weight of the first polymer.

6. The first step is, (1-1) A step of producing a first composite-forming composition comprising a first polymer containing a crosslinking functional group and a ceramic compound, (1-2) The step of unwinding the base film using an unwinder and supplying it to the transport path, (1-3) A step of applying the first composite-forming composition onto the base film to form a coated film, (1-4) A step of transporting the substrate film on which the coating film has been formed to a freezing section and freezing the coating film, (1-5) A step of transporting the substrate film on which the frozen coating film is formed to the thawing section to thaw the frozen coating film and produce the first composite layer, and (1-6) A method for producing a composite solid electrolyte according to any one of claims 1 to 5, comprising the step of winding up and recovering a substrate film containing the first composite layer using a rewinder.

7. The first composite layer comprises an amorphous polymer chain containing a crosslinking structure between the first polymer and the ceramic compound, and crosslinking functional groups. The crosslinking structure between the first polymer and the ceramic compound, and the amorphous polymer chain containing the crosslinking functional group, are formed in steps (1-4) above. The aforementioned cross-linking bonding structure is The crosslinking between the crosslinkable functional groups (a) includes hydrogen bonding, The method for producing a composite solid electrolyte according to claim 6, wherein the crosslinking between the crosslinkable functional group and the ceramic compound includes bonding by Lewis acid-base interaction.

8. A method for producing a composite solid electrolyte according to claim 6, wherein a chemical cross-linker is added to the first composite-forming composition in step (1-1) above, and in step (1-4) above, a cross-linked bonding structure between the first polymer and the ceramic compound, and an amorphous polymer chain containing the cross-linking functional group are formed.

9. The method for producing a composite solid electrolyte according to claim 6, wherein the thawing is performed at 15°C to 35°C.

10. The composite solid according to claim 6, wherein the freezing in step (1-4) and the thawing in step (1-5) are repeated. A method for producing body electrolytes.

11. (1-6) After this stage, the second step is: (2-1) Using an unwinder, the base film containing the first composite layer is unwound, the first composite layer is peeled from the base film and slit, and (2-2) A method for producing a composite solid electrolyte according to claim 6, comprising the step of sintering the slit first composite layer to produce a ceramic ion conductor layer.

12. The method for producing a composite solid electrolyte according to claim 11, wherein the sintering is carried out at 800°C to 1300°C.

13. Following step (2-2) above, the third step is: (3-1) A step of producing a composition containing the second polymer and a lithium salt, (3-2) A step of coating the ceramic ion conductor layer with the composition, and (3-3) A step of drying the coating layer to form a second composite layer, the method for producing a composite solid electrolyte according to claim 6.

14. The second polymer is polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyacrylate, poly(methyl methacrylate, PMMA), PSTFSI, polyurethane, nylon, poly(dimethylsiloxane), gelatin, methylcellulose, agar, dextrin, poly(vinylpyrrolidone), poly(acrylamide), poly(acrylic acid) A method for producing a composite solid electrolyte according to claim 1, comprising one or more selected from the group consisting of (acid), starch-carboxymethylcellulose, hyaluronic acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol.

15. The lithium salt is LiNO ３ , LiOH, LiCl, LiBr, LiI, LiClO ４ , LiBF ４ , LiB １０ Cl １０ , LiPF ６ , LiCF ３ SO ３ , LiCF ３ CO ２ , LiAsF ６ , LiSbF ６ , LiAlCl ４ , CH ３ SO ３ Li, CF ３ SO ３ Li, LiSCN, LiC(CF ３ SO ２ ) ３ , (CF ３ SO ２ ) ２ NLi and (FSO ２ ) ２ The method for producing a composite solid electrolyte according to claim 1, which contains one or more selected from the group consisting of NLi.

16. The method for producing a composite solid electrolyte according to claim 1, wherein the molar ratio of lithium to the second polymer ([Li] / [G]) is 0.1 to 0.

5.

17. The ionic conductivity of the composite solid electrolyte is 10 －５ A method for producing a composite solid electrolyte according to claim 1, wherein the S / cm is 1 or higher.

18. A composite solid electrolyte produced by the manufacturing method described in claim 1, comprising a ceramic ion conductor layer containing a ceramic compound, a second polymer, and a lithium salt.

19. An all-solid-state battery comprising a composite solid electrolyte manufactured by the manufacturing method described in claim 1.

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