Polymer solid electrolyte membrane and method for manufacturing the same

Abstract

The present invention relates to a polymer solid electrolyte film and a method for preparing the same. More specifically, the present invention relates to forming a polymer solid electrolyte film on a release film and then transferring it to a positive electrode or a lithium negative electrode using a transfer process, whereby a uniform polymer solid electrolyte thin film can be obtained.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2023-0174313, filed on December 5, 2023, and Korean Patent Application No. 10-2024-0179288, filed on December 5, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This invention relates to a polymer solid electrolyte membrane and its preparation method. Background Technology

[0004] Lithium-ion batteries using liquid electrolytes have a separator separating the negative and positive electrodes. If this separator is damaged due to deformation or external impact, a short circuit can occur, leading to overheating or an explosion. Therefore, developing a safe solid electrolyte for lithium-ion batteries is a crucial task.

[0005] Lithium-ion batteries using solid electrolytes offer advantages such as improved safety, enhanced reliability through prevention of electrolyte leakage, and ease of manufacturing thin batteries. Furthermore, lithium metal can be used as a negative electrode to increase energy density, making it a promising next-generation battery for applications in small secondary batteries and high-capacity secondary batteries for electric vehicles.

[0006] In solid electrolytes, polymeric materials with ion conductivity can be used as raw materials for polymeric solid electrolytes. Hybrid materials composed of polymeric and inorganic materials have also been proposed. The inorganic materials can be oxides or sulfides, among other inorganic materials.

[0007] Conventional polymer solid electrolytes have been manufactured through a process of forming a coating followed by high-temperature drying. However, conventional polymer solid electrolyte manufacturing techniques are limited by the high crystallinity of crystalline or semi-crystalline polymers, making it difficult to produce polymer solid electrolytes with improved ion conductivity. In other words, the higher the crystallinity of the polymer, the lower the chain mobility of the polymer chains; therefore, it is difficult to improve the ion conductivity of polymer solid electrolytes because the movement of lithium ions within them is restricted.

[0008] Therefore, various methods have been investigated to reduce crystallinity by introducing long-chain portions into the side chains of polymers, or to increase the fluidity of polymer chains by adding additional plasticizers.

[0009] Furthermore, efforts have been made to improve the ionic conductivity of polymer solid electrolytes (PSEs) by adjusting the ratio of polymer matrix to lithium salt in PSEs. However, the increase in lithium salt content leads to a decrease in the mechanical properties of PSEs, thus making the fabrication of uniform and thin self-supporting films of PSEs a challenge.

[0010] Meanwhile, to overcome the limitation of manufacturing thin, self-supporting polymer solid electrolytes due to the deterioration of mechanical properties, methods have been proposed to manufacture polymer solid electrolytes by directly applying polymer solutions to the electrode surface. However, problems related to electrode side reactions have arisen. In particular, in the manufacture of all-solid-state batteries using lithium metal as the negative electrode, side reactions between lithium metal and the polymer solution have been a problem when forming a polymer solid electrolyte film by casting the polymer solution onto the lithium metal.

[0011] Therefore, there is a need to develop manufacturing technologies for polymer solid electrolytes that can prevent side reactions between polymer solid electrolytes and electrodes, have high ionic conductivity, and are in the form of uniform thin films.

[0012] [Prior Art References]

[0013] [Patent References]

[0014] (Patent Reference 1) Korean Patent Application Publication No. 10-2022-0033460 Summary of the Invention

[0015] [Technical Issues]

[0016] The purpose of this invention is to provide a polymer solid electrolyte membrane in the form of a uniform thin film with improved surface properties and ion conductivity through a transfer process.

[0017] Another object of the present invention is to provide a method for preparing polymer solid electrolyte membranes using a transfer process.

[0018] Another object of the present invention is to provide an all-solid-state battery manufactured by transferring a polymer solid electrolyte membrane onto the positive or negative electrode via a transfer process.

[0019] [Technical Solution]

[0020] To achieve the above objectives, the present invention provides a polymer solid electrolyte membrane in the form of a thin film having a uniform surface, wherein the surface roughness (Ra) of one side of the polymer solid electrolyte membrane is less than 1.00 μm.

[0021] In one embodiment of the invention, based on 100 parts by weight of the electrolyte polymer, the polymer solid electrolyte membrane may contain 20 to 100 parts by weight of lithium salt.

[0022] In one embodiment of the invention, the polymer for electrolytes may comprise at least one selected from the group consisting of polyethylene oxide (PEO), polyethylene carbonate (PEC), polypropylene carbonate (PPC), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polyphenylene sulfide (PPS), and derivatives thereof.

[0023] In one embodiment of the present invention, the lithium salt may comprise a fraction selected from (CF3SO2)2NLi (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI), (FSO2)2NLi (lithium bis(fluorosulfonyl)imide, LiFSI), LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 At least one of the following groups: LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, and LiC(CF3SO2)3.

[0024] In one embodiment of the present invention, the ionic conductivity of the polymer solid electrolyte membrane may be at least 1 × 10⁻⁶. -5 S / cm.

[0025] The present invention also relates to a method for manufacturing a polymer solid electrolyte membrane, comprising: (S1) coating a solution for forming a polymer solid electrolyte membrane onto a release membrane and drying it to obtain a polymer solid electrolyte membrane; (S2) placing the polymer solid electrolyte membrane on a positive electrode or a negative electrode to transfer the polymer solid electrolyte membrane; and (S3) separating the release membrane from the polymer solid electrolyte membrane, wherein the peel strength of the release membrane to the polymer solid electrolyte membrane is less than 15 gf / 25 mm.

[0026] In one embodiment of the invention, the release film may comprise at least one selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polyethylene (PE), polybutylene terephthalate (PBT), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyamide (PA), polycarbonate (PC), and polytetrafluoroethylene (PTFE).

[0027] In one embodiment of the present invention, the drying in step (S1) may be a first drying at 20°C to 30°C and a subsequent second drying at 90°C to 110°C.

[0028] In one embodiment of the invention, the solution for forming a polymer solid electrolyte membrane can be prepared by mixing an electrolyte polymer and a lithium salt in a solvent.

[0029] In one embodiment of the invention, the solvent may comprise at least one non-aqueous solvent selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), dioxolane (DOX), dimethoxyethane (DME), diethoxyethane (DEE), γ-butyrolactone (GBL), acetonitrile (AN), and sulfolane.

[0030] In one embodiment of the present invention, the negative electrode may be a lithium negative electrode.

[0031] The present invention also provides an all-solid-state battery comprising a positive electrode, a negative electrode and a polymer solid electrolyte membrane situated between them.

[0032] In one embodiment of the present invention, the surface roughness of one side of the polymer solid electrolyte membrane is less than 1.00 μm, and no additional membrane is formed between the other side of the polymer solid electrolyte membrane and the positive or negative electrode due to side reactions.

[0033] In one embodiment of the present invention, the negative electrode may be a lithium negative electrode.

[0034] [Beneficial Effects]

[0035] The polymer solid electrolyte membrane of the present invention has improved surface properties and ion conductivity due to the transfer process.

[0036] In addition, since it is formed on the release membrane in the form of a polymer solid electrolyte membrane and then transferred to the positive or negative electrode, it has the effect of preventing side reactions between the polymer solid electrolyte membrane and the positive or negative electrode.

[0037] In addition, by forming an electrolyte membrane of the required size and then transferring it, it is easy to form a membrane that is larger than the positive or negative electrode, which has the effect of physically blocking internal short circuits, the main cause of battery fires. Attached Figure Description

[0038] Figure 1 The results show the relationship between the measured ionic conductivity of polymer solid electrolyte membranes prepared using the solution casting process of Comparative Examples 4 to 9 and the molar ratio of EO to Li in the polymer solid electrolyte membrane ([EO]:[Li]).

[0039] Figure 2The results of ionic conductivity measurements of polymer solid electrolyte membranes prepared using the transfer processes of Examples 1 to 6 are shown.

[0040] Figure 3 These are photographs of the transfer process in Example 3 and Comparative Example 1.

[0041] Figure 4 These are photographs illustrating the transfer process in Comparative Examples 1 to 3.

[0042] Figure 5 This is a photograph of the transfer process in Example 6.

[0043] Figures 6a to 6c These are photographs illustrating the formation of polymer solid electrolyte films on lithium metal through transfer, solution casting, and self-supporting film lamination. Detailed Implementation

[0044] The invention will be described in more detail below to provide a better understanding.

[0045] The terms and words used in this specification and claims should not be interpreted in their ordinary or dictionary sense, but rather based on the concepts that the inventor may define as best suited to describe his / her invention, and should be interpreted in a meaning and concept consistent with the technical idea of ​​the invention.

[0046] As used herein, the term "surface roughness" refers to the degree of micro-irregularity on the surface of a polymer solid electrolyte membrane, expressed as the arithmetic mean roughness (Ra) value of randomly measured micro-irregularities formed on the surface of the polymer solid electrolyte membrane. In other words, a larger roughness measurement indicates a rougher surface.

[0047] Polymer solid electrolyte membrane

[0048] This invention relates to a polymer solid electrolyte membrane.

[0049] The polymer solid electrolyte membrane of the present invention is a thin film having a uniform surface, wherein the surface roughness (Ra) of one side of the polymer solid electrolyte membrane is less than 1.00 μm.

[0050] Polymer solid electrolyte membranes can be prepared by the following transfer process in which the polymer solid electrolyte membrane is formed on a release film and then transferred to an electrode to obtain a thin film with a uniform surface.

[0051] Furthermore, the surface roughness (Ra) of the polymer solid electrolyte membrane can be below 1.00 μm, 0.90 μm, 0.80 μm, 0.70 μm, 0.60 μm, 0.50 μm, or 0.40 μm. If the surface roughness is greater than 1.00 μm, the contact with the electrode interface may be unstable, and the lithium-ion transfer capacity may be reduced. Also, if the surface roughness is high, the polymer solid electrolyte membrane may have an uneven surface, which may easily lead to the formation of lithium dendrites and increase the possibility of battery short circuits. Surface roughness can be measured using optical profilometers (OP), atomic force microscopes (AFM), etc. If the polymer solid electrolyte membrane is formed directly on the electrode surface using conventional techniques such as solution casting, it is difficult to obtain a membrane shape due to side reactions between the polymer solid electrolyte in solution and the electrode. Even if a membrane shape is obtained, if continuous degradation occurs due to side reactions between the polymer solid electrolyte and the electrode, it may not be suitable as an electrolyte membrane for maintaining battery performance.

[0052] The polymer solid electrolyte membrane of the present invention forms a polymer solid electrolyte membrane on a release film and then transfers the polymer solid electrolyte membrane to an electrode, thereby preventing side reactions between the polymer solid electrolyte in solution and the electrode, thus obtaining a polymer solid electrolyte membrane with a uniform film morphology.

[0053] The polymer solid electrolyte membrane formed on the release film can be transferred to either the positive or negative electrode. In particular, lithium anodes containing lithium metal are highly reactive, but if a polymer solid electrolyte membrane is formed and then transferred to the lithium anode, side reactions between the polymer solid electrolyte membrane and the lithium anode can be minimized.

[0054] In one embodiment of the present invention, the thickness of the polymer solid electrolyte membrane can be less than 60 μm.

[0055] As described above, even using polymers with low mechanical properties, polymer solid electrolyte membranes in the form of uniform thin films can be prepared via a transfer process. Specifically, the thickness of the polymer solid electrolyte membrane can be less than 60 μm, less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or less than 15 μm. There is no particular limitation on the lower limit of the thickness; for example, it can be greater than 1 μm, greater than 2 μm, greater than 3 μm, or greater than 5 μm.

[0056] In one embodiment of the present invention, the polymer solid electrolyte membrane may comprise an electrolyte polymer and a lithium salt.

[0057] In one embodiment of the invention, the electrolyte polymer may comprise at least one selected from the group consisting of polyethylene oxide (PEO), polyethylene carbonate (PEC), polypropylene carbonate (PPC), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polyphenylene sulfide (PPS), and derivatives thereof. Preferably, the electrolyte polymer may be polyethylene oxide (PEO).

[0058] Furthermore, the weight-average molecular weight (Mw) of the polymer for electrolytes can be from 300,000 g / mol to 4,000,000 g / mol, more specifically, it can be above 300,000 g / mol, above 400,000 g / mol, above 500,000 g / mol, above 600,000 g / mol, above 700,000 g / mol, above 800,000 g / mol, above 900,000 g / mol, above 1,000,000 g / mol, above 1,100,000 g / mol, above 1,200,000 g / mol, above 1,300,000 g / mol, above 1,400,000 g / mol, or above 1,500,000 g / mol, and can be below 4,000,000 g / mol, below 3,500,000 g / mol. Below 3,000,000 g / mol, below 2,500,000 g / mol, or below 2,000,000 g / mol. If the weight-average molecular weight (Mw) of the polymer used for the electrolyte is less than 300,000 g / mol, it may be difficult to obtain a membrane form containing a suitable polymer. If it is greater than 4,000,000 g / mol, the entanglement of polymer chains in the solution used to form the polymer solid electrolyte membrane during the manufacturing process may increase, the solvent permeability into the polymer chains may decrease, and polymer gelation may be accelerated, thereby reducing ionic conductivity. Furthermore, if the weight-average molecular weight (Mw) of the polymer used for the electrolyte is greater than 4,000,000 g / mol, the viscosity of the electrolyte slurry may increase rapidly and become difficult to handle, leading to reduced process efficiency.

[0059] In one embodiment of the present invention, the lithium salt may comprise a fraction selected from (CF3SO2)2NLi (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI), (FSO2)2NLi (lithium bis(fluorosulfonyl)imide, LiFSI), LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10At least one of the following groups: LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, and LiC(CF3SO2)3. Preferably, the lithium salt can be (CF3SO2)2NLi (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI).

[0060] Furthermore, in the polymer solid electrolyte membrane, the lithium salt content can be from 20 parts by weight to 100 parts by weight per 100 parts by weight of the polymer solid electrolyte. If the lithium salt content is less than 20 parts by weight, the ionic conductivity of the polymer solid electrolyte membrane decreases because the crystallinity of the polymer cannot be suppressed. If the lithium salt content is greater than 100 parts by weight, the crystallinity of the polymer decreases due to the reduced mechanical properties of the polymer solid electrolyte membrane. Moreover, if the lithium salt content exceeds 100 parts by weight, it may form aggregates in the electrolyte, which may interfere with ion transfer and ultimately reduce the performance of the electrolyte membrane. Specifically, the lithium salt content can be 20 parts by weight or more, 30 parts by weight or more, 40 parts by weight or more, 50 parts by weight or more, 60 parts by weight or more, or 70 parts by weight or more, and less than 85 parts by weight, less than 90 parts by weight, or less than 100 parts by weight.

[0061] In one embodiment of the invention, the polymer solid electrolyte membrane may comprise polyethylene oxide (PEO) and a lithium salt, wherein the molar ratio ([EO]:[Li]) of the repeating unit ethylene oxide (EO) of PEO to lithium (Li) of the lithium salt may be from 7:1 to 15:1. If the molar ratio ([EO]:[Li]) of ethylene oxide to lithium is less than 7:1, the content of the polymer used in the electrolyte is reduced, which may lead to a deterioration in the mechanical properties of the polymer solid electrolyte, and if it is greater than 15:1, the content of the lithium salt is reduced, which may lead to a deterioration in the ionic conductivity of the polymer solid electrolyte membrane. Specifically, the molar ratio ([EO]:[Li]) of ethylene oxide to lithium may be 7:1 or more, 7.5:1 or more, or 8:1 or more, and may be 10:1 or less, 12:1 or less, or 15:1 or less. The molar ratio of the repeating unit of other polymers besides PEO to lithium may be within the same range as described above.

[0062] In one embodiment of the present invention, the ionic conductivity of the polymer solid electrolyte membrane can be greater than or equal to 1 × 10⁻⁶. -5 S / cm, greater than or equal to 2 × 10 -5 S / cm, or greater than or equal to 3 × 10 -5 S / cm. Within the above range, a higher ionic conductivity value is advantageous. There is no particular upper limit to the ionic conductivity; for example, it can be 5 × 10⁻⁶. -5Below S / cm, or 6 × 10 -5 Below S / cm.

[0063] In one embodiment of the invention, a polymer solid electrolyte membrane can be readily fabricated in a large size relative to the positive or negative electrode. Since the polymer solid electrolyte membrane is not formed directly on the positive or negative electrode, but rather a uniform thin film of polymer solid electrolyte is first prepared and then transferred to the positive or negative electrode, a polymer solid electrolyte membrane larger than the positive or negative electrode can be readily fabricated, and the contact between the positive and negative electrodes can be blocked to prevent internal short circuits.

[0064] Typically, electrolyte polymers such as polyethylene oxide (PEO) have high crystallinity, making it difficult to use PEO as a raw material to manufacture polymer solid electrolyte membranes with high ion conductivity. Attempts have been made to overcome this problem by reducing the crystallinity of PEO. However, when reducing the crystallinity of PEO to prepare thin electrolyte membranes, it is difficult to produce uniform electrolyte membranes due to reduced mechanical properties. Therefore, by introducing a transfer process, polymer solid electrolyte membranes with high ion conductivity can still be prepared based on electrolyte polymers such as PEO. Furthermore, the transfer process allows for the production of electrolyte membranes with a larger area than the substrate, providing the advantage of physically preventing internal short circuits caused by contact between the positive and negative electrodes (which can lead to battery fires).

[0065] The polymer solid electrolyte membrane described above can be prepared as a self-supporting membrane in the form of a uniform thin film using a transfer process.

[0066] Preparation method of polymer solid electrolyte membrane

[0067] The present invention also relates to a method for preparing a polymer solid electrolyte membrane.

[0068] The method for manufacturing the polymer solid electrolyte membrane of the present invention includes: (S1) coating a solution for forming the polymer solid electrolyte membrane onto a release membrane and drying it to obtain the polymer solid electrolyte membrane; (S2) placing the polymer solid electrolyte membrane on a positive electrode or a negative electrode to transfer the polymer solid electrolyte membrane; and (S3) separating the release membrane from the polymer solid electrolyte membrane, wherein the peel strength of the release membrane relative to the polymer solid electrolyte membrane is less than 15 gf / 25 mm.

[0069] The preparation method of the polymer solid electrolyte membrane of the present invention will be described in more detail below. The properties and contents of the raw materials used in the manufacturing method are as described above.

[0070] In one embodiment of the present invention, in step (S1), a polymer solid electrolyte membrane can be obtained by coating a solution for forming a polymer solid electrolyte membrane onto a release membrane and then drying it.

[0071] The peel strength of the release film relative to the polymer solid electrolyte membrane can be below 15 gf / 25 mm. If the peel strength is greater than 15 gf / 25 mm, it may be difficult to separate the release film from the polymer solid electrolyte membrane, and the transfer process may not proceed smoothly. Specifically, the peel strength can be below 15 gf / 25 mm, below 13 gf / 25 mm, below 10 gf / 25 mm, below 8 gf / 25 mm, or below 5 gf / 25 mm. There is no particular limitation on the lower limit of the peel strength; for example, it can be above 0.5 gf / 25 mm.

[0072] Furthermore, by setting the peel strength of the release film to the above range, the polymer solid electrolyte layer formed by removing the release film can be prepared into a uniform film with a surface roughness of less than 1.00 μm.

[0073] Furthermore, the release film only needs to meet the above-mentioned peel strength requirements and is not particularly limited. For example, the release film may contain at least one material selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polyethylene (PE), polybutylene terephthalate (PBT), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyamide (PA), polycarbonate (PC), and polytetrafluoroethylene (PTFE).

[0074] Furthermore, there are no particular limitations on the thickness of the release film; for ease of processing, it can range from 10 μm to 100 μm. If the release film thickness is less than 10 μm, the surface roughness of the solid electrolyte membrane formed on it may also become rough due to differences in surface roughness, and the release film may crack or break during the process. If the release film thickness exceeds 100 μm, it becomes too thick and heavy, which may cause problems such as sagging during the process. Specifically, the thickness of the release film can be greater than 10 μm, greater than 20 μm, greater than 30 μm, or greater than 40 μm, and can be less than 100 μm, less than 90 μm, less than 80 μm, less than 70 μm, or less than 60 μm.

[0075] The solution used to form the polymer solid electrolyte membrane can be prepared by mixing an electrolyte polymer and a lithium salt in a solvent. The types and weights of the electrolyte polymer and the lithium salt are as described above.

[0076] Furthermore, the concentration of the solution used to form the polymer solid electrolyte membrane can be appropriately adjusted to ensure the smooth operation of the coating process when the solution is applied to the release film. For example, the concentration of the solution used to form the polymer solid electrolyte membrane can be between 3% and 10%, more specifically, it can be above 3%, above 4%, or above 5%, and below 6%, below 8%, or below 10%. If the concentration of the solution used to form the polymer solid electrolyte membrane is less than 3%, the concentration is too low, which may cause it to be lost when coated onto the release film, and if it exceeds 10%, it is difficult to dissolve the required amount of lithium salt in the solution, and the high viscosity may make it difficult to coat the solution in a uniform film form.

[0077] Furthermore, there are no particular limitations on the solvent, as long as it can uniformly disperse the electrolyte, polymer, and lithium salt to form a solution. For example, the solvent may include at least one non-aqueous solvent selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), dioxolane (DOX), dimethoxyethane (DME), diethoxyethane (DEE), γ-butyrolactone (GBL), acetonitrile (AN), and sulfolane.

[0078] Furthermore, there are no particular limitations on the coating method, as long as it can uniformly coat the solution used to form the polymer solid electrolyte membrane onto the release film. For example, the coating method can be rod coating, roller coating, spin coating, slot coating, die coating, doctor blade coating, comma coating, slot die coating, lip coating, or solution casting.

[0079] The drying process can consist of a first drying at 20°C to 40°C and a second drying at 80°C to 120°C. The first drying removes the solvent, while the second drying enhances the mechanical properties of the polymer solid electrolyte membrane.

[0080] In addition, the temperature of the first drying process can be above 20°C, above 21°C, or above 22°C, and can be below 30°C, below 35°C, or below 40°C. If the temperature of the first drying process is below 20°C, the solvent in the polymer solid electrolyte membrane may not be completely removed. If the temperature is above 40°C, the evaporation rate of the solvent is excessively accelerated, resulting in pitted shapes on the surface of the electrolyte membrane, leading to increased surface roughness.

[0081] In addition, the temperature of the second drying process can be above 80°C, above 85°C, or above 90°C, and can be below 100°C, below 115°C, or below 120°C. If the temperature of the second drying process is below 80°C, a film may not be formed; if the temperature is above 120°C, the polymer or lithium salt used as an electrolyte in the film may denature, leading to a decrease in properties such as ionic conductivity.

[0082] In one embodiment of the invention, in step (S2), the polymer solid electrolyte membrane can be placed on the positive or negative electrode and transferred thereon. In this case, the side of the polymer solid electrolyte membrane other than the side adjacent to the release membrane can be placed on the positive or negative electrode.

[0083] The transfer can include placing a polymer solid electrolyte membrane on the positive or negative electrode and then using a tool (e.g., a roller) to adhere the polymer solid electrolyte membrane to the interface of the positive or negative electrode. The polymer solid electrolyte membrane is inherently adhesive, so it can be easily transferred without a high-pressure pressurization process.

[0084] Furthermore, since the polymer solid electrolyte membrane is already formed on the release membrane in the form of a film before being transferred to the positive or negative electrode, side reactions between the polymer solid electrolyte membrane and the positive or negative electrode can be prevented. If the solution used to form the polymer solid electrolyte membrane is coated onto the positive or negative electrode to directly form the membrane, side reactions may occur between the raw materials, which exist in a highly free state in the solution, and the positive or negative electrode, leading to a deterioration of the interfacial properties of the positive or negative electrode, or potentially the formation of additional membranes through side reactions.

[0085] In addition, lithium in lithium anodes containing lithium metal is highly reactive, but side reactions can be prevented by using a transfer process to transfer a polymer solid electrolyte membrane onto the lithium anode.

[0086] In one embodiment of the present invention, in the above step (S3), the release film can be removed from the polymer solid electrolyte membrane.

[0087] Once the polymer solid electrolyte membrane is adhered to the positive or negative electrode in step (S2), the release membrane can be removed, and the transfer process is complete.

[0088] All-solid-state batteries

[0089] The present invention also relates to an all-solid-state battery comprising the above-described polymer solid electrolyte, wherein the all-solid-state battery comprises a negative electrode, a positive electrode and a polymer solid electrolyte membrane between the negative electrode and the positive electrode, and the polymer solid electrolyte membrane has the above-described features.

[0090] In one embodiment of the present invention, the surface roughness of one side of the polymer solid electrolyte membrane is less than 1.00 μm, and no additional membrane is formed between the other side of the polymer solid electrolyte membrane and the positive or negative electrode due to side reactions.

[0091] The polymer solid electrolyte membrane is formed on a release membrane in the form of a membrane and then transferred to the positive or negative electrode, so that the side of the polymer solid electrolyte membrane after the release membrane is removed has uniform surface properties.

[0092] Therefore, side reactions between the polymer solid electrolyte membrane and the positive or negative electrode, which can be easily physically contacted, are prevented.

[0093] Furthermore, by preventing side reactions at the interface between the polymer solid electrolyte membrane and the positive or negative electrode, no additional membrane caused by side reactions is formed. When side reactions occur, the continuous depletion of the electrolyte membrane leads to a decline in battery performance. When side reactions are suppressed, a stable battery with no performance degradation can be manufactured.

[0094] In particular, the negative electrode can be a lithium negative electrode, and side reactions between the negative electrode containing highly reactive lithium metal and the polymer solid electrolyte membrane can be prevented.

[0095] In one embodiment of the present invention, the positive electrode included in the all-solid-state battery comprises a positive electrode active material layer, wherein the positive electrode active material layer may be formed on one side of the positive electrode current collector.

[0096] The positive electrode active material layer includes the positive electrode active material, the binder, and the conductive material.

[0097] Furthermore, the positive electrode active material can be any material capable of reversibly adsorbing and releasing lithium ions, without particular limitations; for example, layered compounds such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and Li[Ni] x Co y Mn z M v O2 (where M is any one or more elements selected from Al, Ga, and In; and 0.3≤x<1.0, 0≤y, z≤0.5, 0≤v≤0.1 and x+y+z+v=1), Li (Li a M b-a-b’ M' b’ )O 2-c A c(where 0 ≤ a ≤ 0.2, 0.6 ≤ b ≤ 1, 0 ≤ b' ≤ 0.2 and 0 ≤ c ≤ 0.2; M includes at least one selected from the group consisting of Mn, Ni, Co, Fe, Cr, V, Cu, Zn and Ti; M' includes at least one selected from Al, Mg and B; A includes at least one selected from P, F, S and N), or a compound substituted with one or more transition metals; lithium manganese oxide, such as Li 1+y Mn 2-y Compounds of O4 (where y is 0 to 0.33), LiMnO3, LiMn2O3, or LiMnO2; lithium copper oxides (Li2CuO2); vanadium oxides, such as LiV3O8, LiFe3O4, V2O5, or Cu2V2O7; and compounds of the formula LiNi 1-y M y Ni-site type lithium nickel oxide represented by O2 (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and y is 0.01 to 0.3); LiMn 2-y M y Lithium manganese composite oxides represented by O2 (where M is Co, Ni, Fe, Cr, Zn or Ta, and y is 0.01 to 0.1) or Li2Mn3MO8 (where M is Fe, Co, Ni, Cu or Zn); LiMn2O4, wherein part of the Li in the formula is replaced by an alkaline earth metal ion; disulfides; Fe2(MoO4)3, etc., but not limited to these.

[0098] Furthermore, based on the total weight of the positive electrode active material layer, the content of the positive electrode active material can be between 40% and 80% by weight. Specifically, the content of the positive electrode active material can be above 40% or 50% by weight, or below 70% or 80% by weight. If the content of the positive electrode active material is less than 40% by weight, the connection between the wet and dry positive electrode active material layers may be insufficient; if it is greater than 80% by weight, the mass transfer resistance may be large.

[0099] Additionally, the adhesive is a component that facilitates the bonding of the positive electrode active material to the conductive material or to the current collector, and may include at least one selected from the group consisting of: styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile copolymer, acrylonitrile-butadiene rubber, nitrile rubber, acrylonitrile-styrene-butadiene copolymer, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene / propylene copolymer, polybutadiene, polyoxyethylene, chlorosulfonated polyethylene, polyvinylpyrrolidone, polyvinylpyridine, and poly(ethylene oxide). Vinyl alcohol, polyvinyl acetate, polyepoxychloropropane, polyphosphazene, polyacrylonitrile, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl cellulose, cyanoethyl sucrose, polyester, polyamide, polyether, polyimide, polycarboxylate, polycarboxylic acid, polyacrylic acid, polyacrylate, lithium polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyurethane, polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene copolymer. Advantageously, the adhesive may include at least one selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethyl cellulose, polyacrylic acid, lithium polyacrylate, and polyvinylidene fluoride.

[0100] Furthermore, based on the total weight of the positive electrode active material layer, the binder content can range from 1% to 30% by weight, and more specifically, the binder content can be greater than or equal to 1% by weight, or greater than or equal to 3% by weight, and less than or equal to 15% by weight, or less than or equal to 30% 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 the binder content is greater than 30% by weight, the adhesion may increase, but the content of the positive electrode active material may decrease, leading to a decrease in battery capacity.

[0101] Furthermore, there are no particular restrictions on conductive materials, as long as they can prevent side reactions in the internal environment of the all-solid-state battery and have excellent conductivity without causing chemical changes in the battery. Representative examples include graphite or conductive carbon, such as natural graphite, artificial graphite, etc.; carbon black, such as carbon black, acetylene black, Ketjen black, Denka black, thermal cracking carbon black, channel black, furnace black, lamp black, summer black, etc.; carbon-based materials with graphene or graphite crystal structures; conductive fibers, such as carbon fibers, metal fibers, etc.; fluorinated carbon; metal powders, such as aluminum powder, nickel powder, etc.; conductive whiskers, such as zinc oxide, potassium titanate, etc.; conductive oxides, such as titanium oxide; and conductive polymers, such as polyphenylene derivatives. The above can be used alone or in mixtures of two or more, but are not limited to these.

[0102] Furthermore, based on the total weight of the positive electrode active material layer, the content of conductive material can range from 0.5% to 30% by weight, and more specifically, the content of conductive material can be greater than 0.5% by weight or greater than 1% by weight, and can be less than 20% by weight or less than 30% by weight. If the content of conductive material is too low, for example less than 0.5% by weight, it is difficult to expect an improvement in conductivity or the electrochemical properties of the battery may deteriorate, and if it is too high, for example greater than 30% by weight, the amount of positive electrode active material may be relatively small, resulting in a decrease in capacity and energy density. There are no substantial limitations on the method of incorporating conductive material into the positive electrode, and any conventional method known in the art can be used, such as coating the positive electrode active material.

[0103] In addition, the positive current collector supports the positive active material layer and is used to transfer electrons between the external wire and the positive active material layer.

[0104] There are no particular restrictions on the positive electrode current collector, as long as it has high conductivity and does not cause chemical changes in the all-solid-state battery. For example, copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, and copper or stainless steel, aluminum-cadmium alloys with carbon, nickel or silver surface treatment can be used as positive electrode current collectors.

[0105] To enhance the bonding force with the positive electrode active material layer, the positive electrode current collector can have a microscopic uneven structure, or a three-dimensional porous structure can be adopted on the surface of the positive electrode current collector. Therefore, the positive electrode current collector can include various forms, such as membranes, sheets, foils, meshes, porous materials, foams, nonwoven materials, etc.

[0106] The positive electrode as described above can be manufactured according to conventional methods, more specifically, by the following process: coating a positive electrode active material layer forming composition, prepared by mixing positive electrode active material with conductive material and binder in an organic solvent, onto a positive electrode current collector and drying it, and optionally compressing it onto the current collector to increase the 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 is easily evaporable. Examples specifically include acetonitrile, methanol, ethanol, tetrahydrofuran, water, and isopropanol.

[0107] In one embodiment of the present invention, the negative electrode included in the all-solid-state battery comprises a negative electrode active material layer, wherein the negative electrode active material layer may be formed on one side of the negative electrode current collector.

[0108] Negative electrode active materials may include those capable of reversibly inserting or de-intercalating lithium (Li) + Materials that can react with lithium ions to reversibly form lithium-containing compounds, lithium metal, or lithium alloys.

[0109] Capable of reversibly inserting or de-inserting lithium (Li) +The material can be, for example, crystalline carbon, amorphous carbon, or a mixture thereof. It is capable of reacting with lithium ions (Li... + The materials used to reversibly form lithium-containing compounds in the reaction can be, for example, tin oxide, titanium nitrate, or silicon. Lithium alloys can be, for example, alloys of lithium (Li) with metals selected from 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).

[0110] Preferably, the negative electrode active material can be lithium metal, more specifically in the form of a lithium metal film or lithium metal powder.

[0111] Based on the total weight of the negative electrode active material layer, the content of the negative electrode active material can range from 40% to 80% by weight. Specifically, the content of the negative electrode active material can be above 40% by weight or above 50% by weight, and below 70% by weight or below 80% by weight. If the content of the negative electrode active material is less than 40% by weight, the connectivity between the wet and dry negative electrode active material layers may be insufficient, and if the content is greater than 80% by weight, the mass transfer resistance may be greater.

[0112] In addition, the adhesive is as described above for the positive electrode active material layer.

[0113] In addition, the conductive material is as described above for the positive electrode active material layer.

[0114] Furthermore, there are no particular restrictions on the negative electrode current collector, as long as it is conductive and does not cause chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and copper or stainless steel, aluminum-cadmium alloys with surfaces treated with carbon, nickel, or silver can be used. In addition, like the positive electrode current collector, the negative electrode current collector can take various forms, such as films, sheets, foils, meshes, porous materials, foams, and nonwoven materials with finely textured surfaces.

[0115] There are no particular limitations on the manufacturing method of the negative electrode. It can be manufactured by forming a layer of negative electrode active material on the negative electrode current collector using conventional layer or film forming methods. For example, methods such as pressing, coating, or deposition can be used. The negative electrode of the present invention also includes a case in which a thin film of metallic lithium is formed on a metal plate after initial charging of the battery without a lithium film on the negative electrode current collector.

[0116] Furthermore, the present invention provides a battery module comprising the above-mentioned all-solid-state battery as a unit cell; a battery pack comprising the above-mentioned battery module; and an apparatus comprising the above-mentioned battery pack as a power source.

[0117] Specific examples of such devices include, but are not limited to, power tools powered by electric motors; electric vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.; electric two-wheelers, including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; energy storage systems; and so on.

[0118] [Example]

[0119] In the following description, preferred embodiments of the invention are presented for the purpose of illustrating the invention. However, it will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the invention and its technical concept, and that such changes and modifications fall within the scope of the appended claims.

[0120] In the following examples and comparative examples, polymer solid electrolyte membranes and all-solid-state batteries were prepared according to the compositions, release membrane types and methods described in Table 1 below.

[0121] [Table 1]

[0122] Example 1

[0123] A solution for forming a polymeric solid electrolyte was prepared by mixing the electrolyte, polymeric polyethylene oxide (Mw: 600 kg / mol, Sigma Aldrich), and lithium salt LiTFSI in the solvent acetonitrile. Mixing was performed by stirring with a magnetic rod at 90 °C for 24 hours. The solution was prepared to contain 5.8% polyethylene oxide.

[0124] The solution used to form the polymer solid electrolyte was coated onto release film A (peel strength: 12 gf / 25 mm, thickness: 38 μm). After solution casting, it was first dried at room temperature for 12 hours, and then dried at 100°C for 12 hours to form a 12 μm thick polymer solid electrolyte film. The polymer solid electrolyte film was transferred onto a stainless steel (SS) substrate for a coin cell, and the release film was removed to assemble the coin cell.

[0125] Example 2

[0126] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 27 μm.

[0127] Example 3

[0128] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 37 μm.

[0129] Example 4

[0130] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 45 μm.

[0131] Example 5

[0132] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 51 μm.

[0133] Example 6

[0134] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane B (peel strength: 2 gf / 25 mm, thickness: 78 μm) was used instead of release membrane A, and the thickness of the polymer solid electrolyte membrane was 40 μm.

[0135] Example 7

[0136] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane F (peel strength: 4.2 gf / 25 mm, thickness: 50 μm) was used instead of release membrane A, and the thickness of the polymer solid electrolyte membrane was 50 μm.

[0137] Example 8

[0138] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane G (peel strength: 7.7 gf / 25 mm, thickness: 78 μm) was used instead of release membrane A, and the thickness of the polymer solid electrolyte membrane was 50 μm.

[0139] Example 9

[0140] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane H (peel strength: 10.7 gf / 25 mm, thickness: 76 μm) was used instead of release membrane A, and the thickness of the polymer solid electrolyte membrane was 50 μm.

[0141] Comparative Example 1

[0142] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane C (peel strength: 18 gf / 25 mm, thickness: 50 μm) was used instead of release membrane A.

[0143] Comparative Example 2

[0144] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane D (peel strength: 455 gf / 25 mm, thickness: 78 μm) was used instead of release membrane A.

[0145] Comparative Example 3

[0146] The polymer solid electrolyte membrane and the coin cell were prepared using the same method as in Example 1, except that release membrane E (peel strength: 600 gf / 25 mm, thickness: 39 μm) was used instead of release membrane A.

[0147] Comparative Example 4

[0148] Instead of casting the solution used to form the polymer solid electrolyte membrane in Example 1 onto the release membrane A, the solution was cast onto a stainless steel (SS) substrate that serves as the bottom substrate of the coin cell, and then dried first at room temperature for 12 hours, and then dried at 100°C for 12 hours to form a 100 μm thick polymer solid electrolyte membrane.

[0149] Comparative Example 5

[0150] The polymer solid electrolyte membrane and the coin cell were prepared in the same manner as in Comparative Example 4, except that, in preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) to lithium (Li) of the lithium salt ([EO] / [Li]) was 16:1, and 40.7 parts by weight of LiTFSI were mixed relative to 100 parts by weight of ethylene oxide.

[0151] Comparative Example 6

[0152] The polymer solid electrolyte membrane and the coin cell were prepared in the same manner as in Comparative Example 4, except that, in preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) to lithium (Li) of the lithium salt ([EO] / [Li]) was 12:1, and 54.3 parts by weight of LiTFSI were mixed relative to 100 parts by weight of ethylene oxide.

[0153] Comparative Example 7

[0154] The polymer solid electrolyte membrane and the coin cell were prepared in the same manner as in Comparative Example 4, except that, in preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) to lithium (Li) of the lithium salt ([EO] / [Li]) was 8:1, and 81.3 parts by weight of LiTFSI were mixed relative to 100 parts by weight of ethylene oxide.

[0155] Comparative Example 8

[0156] The polymer solid electrolyte membrane and the coin cell were prepared in the same manner as in Comparative Example 4, except that, in preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) to lithium (Li) of the lithium salt ([EO] / [Li]) was 6:1, and 108.7 parts by weight of LiTFSI were mixed relative to 100 parts by weight of ethylene oxide.

[0157] Comparative Example 9

[0158] The polymer solid electrolyte membrane and the coin cell were prepared in the same manner as in Comparative Example 4, except that, in preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) to lithium (Li) of the lithium salt ([EO] / [Li]) was 4:1, and 130.3 parts by weight of LiTFSI were mixed relative to 100 parts by weight of ethylene oxide.

[0159] Comparative Example 10

[0160] A polymer solid electrolyte membrane was formed on a release membrane in the same manner as in Example 1, except that the thickness was 38 μm. The dried polymer solid electrolyte membrane was then separated from the release membrane to prepare a self-supporting polymer solid electrolyte film without a support.

[0161] Experimental Example 1: Determination of Ionic Conductivity in Polymer Solid Electrolyte Membranes

[0162] To measure the ionic conductivity of the polymer solid electrolyte membranes prepared in the examples and comparative examples, the polymer solid electrolyte membranes were stamped to a size of 1.7671 cm. 2 The coin battery is made by placing a stamped polymer solid electrolyte between two stainless steel (SS) plates in a circular shape.

[0163] After measuring the resistance using an electrochemical impedance spectroscopy (EIS, VM3, BioLogic 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 polymer solid electrolyte membrane was calculated using the following Equation 1.

[0164] [Equation 1]

[0165] In equation 1, σ i R is the ionic conductivity (S / cm) of the polymer solid electrolyte membrane, R is the resistance (Ω) of the polymer solid electrolyte membrane measured by an electrochemical impedance spectroscopy, L is the thickness (μm) of the polymer solid electrolyte membrane, and A is the area (cm²) of the polymer solid electrolyte membrane.2 ).

[0166] Figure 1 Table 2 below shows the relationship between the ionic conductivity measurements of polymer solid electrolyte membranes prepared using solution casting and the molar ratio of EO to Li ([EO]:[Li]).

[0167] [Table 2]

[0168] like Figure 1 As shown in Table 2 above, and as in Comparative Example 7, it was found that the ionic conductivity of the polymer solid electrolyte membrane prepared by solution casting was highest when the [EO]:[Li] ratio was 8:1.

[0169] Figure 2 Table 3 below shows the ionic conductivity measurements of the polymer solid electrolyte membranes prepared using the transfer process.

[0170] The [EO]:[Li] ratio of the polymer solid electrolyte membranes in Examples 1 to 9 below is 8:1, which corresponds to the excellent [EO]:[Li] conductivity of the polymer solid electrolyte membranes in Table 1 above.

[0171] [Table 3]

[0172] Reference Figure 2 As shown in Table 3 above, Example 6 exhibits high ionic conductivity. The peel strength of the release film used in Example 6 is 2 gf / 25 mm, lower than the peel strength of 12 gf / 25 mm used in Examples 1 to 5. This indicates that when manufacturing polymer solid electrolyte membranes, if the release film used in the transfer process has a lower peel strength, the electrolyte membrane and the release film can easily separate, suppressing deformation such as breakage or stretching, reducing process problems, and resulting in high ionic conductivity.

[0173] Experimental Example 2: Confirmation of the Feasibility of the Transfer Process

[0174] The transfer processes of Example 3, Comparative Example 1, and Comparative Example 2 were visually verified. The peel strengths of the release films used in the transfer processes of Example 3, Comparative Example 1, and Comparative Example 2 were 12 gf / 25 mm, 18 gf / 25 mm, and 455 gf / 25 mm, respectively.

[0175] Figure 3 These are photographs illustrating the feasibility of the transfer processes in Example 3 and Comparative Example 1. In the manufacture of polymer solid electrolyte membranes, it was observed that the feasibility of the transfer process depends on the peel strength of the release film used in the transfer process.

[0176] Reference Figure 3 As can be seen, compared with Example 1, the release film used in the transfer process of Comparative Example 1 has a higher peel strength. Therefore, the release film 10 did not peel off from the polymer solid electrolyte membrane 20. When attempting to separate the release film from the solid electrolyte membrane by external force, damage and deformation of the membrane were observed. This indicates that release films with a peel strength of 18 gf / 25 mm or higher cannot be transferred.

[0177] Figure 4 These are photographs observing the transfer processes of Comparative Examples 1 to 3.

[0178] Reference Figure 4 It can be confirmed that if the release film used in the transfer process has a high peel strength, the release film 10 cannot be separated from the polymer solid electrolyte membrane 20, resulting in the deformation of the membrane in the transfer process and making it difficult to transfer the polymer solid electrolyte membrane 20 onto the lithium anode 30.

[0179] The peel strengths of the release film 10 used in the transfer processes of Comparative Examples 1, 2 and 3 were 18 gf / 25 mm, 455 gf / 25 mm and 600 gf / 25 mm, respectively. Therefore, it can be concluded that the peel strength of the release film should be less than this value.

[0180] Figure 5 This is a photograph showing the transfer process used to manufacture the polymer solid electrolyte membrane of Example 6.

[0181] Reference Figure 5 As can be seen, the polymer solid electrolyte membrane 20 formed on the release membrane 10 is easily peeled off from the release membrane 10 (a). Utilizing these properties, the polymer solid electrolyte membrane 20 can be transferred to the surface of the lithium anode 30 to be transferred while removing the release membrane 10 on one side of the polymer solid electrolyte membrane 20 (b), thereby obtaining a polymer solid electrolyte membrane 20 in a state of being stacked with the lithium anode 30 (c).

[0182] Experimental Example 3: Measurement of Surface Roughness

[0183] To measure the surface roughness of the polymer solid electrolyte membranes of Example 6 and Comparative Example 7, prepared by transfer process and solution casting method respectively, samples of the polymer solid electrolyte membranes prepared in Example 6 and Comparative Example 7 were prepared to a size of 1 cm. 2 The square shape is attached to a surface roughness measuring bracket with a carbon ribbon while adhering to the release film.

[0184] The surface roughness Ra of a 2D surface with a width of 0.5 mm and a length of 0.5 mm was measured at room temperature in WSI mode using a 3D optical profilometer (OP, NV-F2700, Nano System).

[0185] The polymer solid electrolyte membrane of Comparative Example 7, prepared by solution casting, has an Ra of 1.3 μm or more, while the polymer solid electrolyte membrane of Example 6, prepared by transfer method, has an Ra of 0.4 μm or less.

[0186] Therefore, it can be found that polymer solid electrolyte membranes manufactured by the transfer method have more uniform and smooth surface roughness characteristics compared with membranes manufactured by the solution casting method.

[0187] Experiment Example 4: Confirm whether side reactions occur between the polymer solid electrolyte membrane and lithium metal.

[0188] The polymer solid electrolyte membrane from Example 1 was transferred onto lithium metal, and it was observed whether any side reactions occurred between the polymer solid electrolyte membrane and the lithium metal.

[0189] In addition, the solution used to form the polymer solid electrolyte membrane in Comparative Example 4 was cast onto lithium metal to form the polymer solid electrolyte membrane, and it was observed whether any side reactions occurred between the polymer solid electrolyte membrane and the lithium metal.

[0190] In addition, the self-supporting polymer solid electrolyte membrane of Example 10 was laminated onto lithium metal.

[0191] Figures 6a to 6c These are photographs illustrating the formation of polymer solid electrolyte films on lithium metal through transfer, solution casting, and self-supporting film lamination, respectively.

[0192] As a result, Figure 6a As shown, it was found that in Example 1, the polymer solid electrolyte membrane was transferred onto the lithium metal and the polymer solid electrolyte membrane was retained without further side reactions.

[0193] On the other hand, such as Figure 6b As shown, in Comparative Example 4, when a polymer solid electrolyte film was formed on lithium metal by solution casting, it was found that a side reaction occurred between the solution used to form the polymer solid electrolyte film and the lithium metal, and the polymer solid electrolyte film could not be formed normally.

[0194] In addition, such as Figure 6c As shown, it was found that the self-supporting polymer solid electrolyte membrane prepared in Comparative Example 10 underwent membrane deformation once separated from the release membrane, and folded and slid on the lithium metal, hindering proper lamination.

[0195] Although the invention has been described above with limited examples and figures, it is not limited thereto, and those skilled in the art can make various modifications and variations within the scope of the technical concept of the invention and the equivalents of the patent claims set forth below.

[0196] [Figure Labels]

[0197] 10: Release film

[0198] 20: Polymer solid electrolyte membrane

[0199] 30: Lithium anode

Claims

1. A polymer solid electrolyte membrane in the form of a thin film having a uniform surface, in, The surface roughness Ra of one side of the polymer solid electrolyte membrane is less than 1.00 μm.

2. The polymer solid electrolyte membrane according to claim 1, in, Based on 100 parts by weight of an electrolyte polymer, the polymer solid electrolyte membrane contains 20 to 100 parts by weight of a lithium salt.

3. The polymer solid electrolyte membrane according to claim 2, in, The electrolyte polymer comprises at least one selected from the group consisting of polyethylene oxide (PEO), polyethylene carbonate (PEC), polypropylene carbonate (PPC), polyvinylidene fluoride (PVDF), polyethylene glycol (PEG), polyphenylene sulfide (PPS), and their derivatives.

4. The polymer solid electrolyte membrane according to claim 2, in, The lithium salt comprises, selected from (CF3SO2)2NLi (lithium bis(trifluoromethanesulfonyl)imide, LiTFSI), (FSO2)2NLi (lithium bis(fluorosulfonyl)imide, LiFSI), LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 At least one of the following groups: LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, and LiC(CF3SO2)3.

5. The polymer solid electrolyte membrane according to claim 1, in, The polymer solid electrolyte membrane has an ionic conductivity of at least 1 × 10⁻⁶. -5 S / cm.

6. A method for manufacturing a polymer solid electrolyte membrane, comprising the following steps: (S1) The solution used to form the polymer solid electrolyte membrane is coated onto the release film and dried to obtain the polymer solid electrolyte membrane; (S2) Place the polymer solid electrolyte membrane on the positive or negative electrode to transfer the polymer solid electrolyte membrane; and (S3) Separate the release membrane from the polymer solid electrolyte membrane. The release film has a peel strength of less than 15 gf / 25 mm over the polymer solid electrolyte membrane.

7. The method for manufacturing the polymer solid electrolyte membrane according to claim 6, in, The release film comprises at least one selected from the group consisting of polyethylene terephthalate (PET), polyimide (PI), polyethylene (PE), polybutylene terephthalate (PBT), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), polyamide (PA), polycarbonate (PC), and polytetrafluoroethylene (PTFE).

8. The method for manufacturing the polymer solid electrolyte membrane according to claim 6, in, The drying in step (S1) consists of a first drying at 20°C to 30°C and a second drying at 90°C to 110°C.

9. The method for manufacturing the polymer solid electrolyte membrane according to claim 6, in, The solution for forming the polymer solid electrolyte membrane is prepared by mixing an electrolyte polymer and a lithium salt in a solvent.

10. The method for manufacturing the polymer solid electrolyte membrane according to claim 9, in, The solvent comprises at least one non-aqueous solvent selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), dioxolane (DOX), dimethoxyethane (DME), diethoxyethane (DEE), γ-butyrolactone (GBL), acetonitrile (AN), and sulfolane.

11. The method for manufacturing the polymer solid electrolyte membrane according to claim 6, in, The negative electrode is a lithium negative electrode.

12. An all-solid-state battery comprising a positive electrode, a negative electrode, and a polymer solid electrolyte membrane of claim 1 situated therebetween.

13. The all-solid-state battery according to claim 12, in, The surface roughness on one side of the polymer solid electrolyte membrane is less than 1.00 μm, and no additional membrane will be formed between the other side of the polymer solid electrolyte membrane and the positive or negative electrode due to side reactions.

14. The all-solid-state battery according to claim 12, in, The negative electrode is a lithium negative electrode.

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