Polymer solid electrolyte membrane and manufacturing method therefor

Abstract

The present invention relates to a polymer solid electrolyte membrane and a manufacturing method therefor. More specifically, a polymer solid electrolyte membrane is formed on a release film, and then is transferred to a cathode or a lithium anode by using a transfer process, and thus a polymer solid electrolyte membrane of a uniform thin film can be obtained.

Description

Polymer solid electrolyte membrane and method for manufacturing the same

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0174313, filed December 5, 2023, and Korean Patent Application No. 10-2024-0179288, filed December 5, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a polymer solid electrolyte membrane and a method for manufacturing the same.

[0005] Lithium secondary batteries using liquid electrolytes have a structure where the anode and cathode are separated by a separator. Damage to the separator due to deformation or external impact can cause a short circuit, potentially leading to risks such as overheating or explosion. Therefore, the development of a solid electrolyte that can ensure safety in lithium secondary batteries is a critical task.

[0006] Lithium secondary batteries using solid electrolytes offer enhanced safety, improved reliability by preventing electrolyte leakage, and the ease of manufacturing thin batteries. Furthermore, the use of lithium metal as the anode enhances energy density. These batteries are attracting attention as next-generation batteries, promising applications in small-sized secondary batteries and high-capacity secondary batteries for electric vehicles.

[0007] Among solid electrolytes, polymer materials with ion conductivity can be used as raw materials for polymer solid electrolytes. Hybrid materials that combine polymer materials with inorganic materials have also been proposed. Inorganic materials such as oxides or sulfides can be used as the inorganic materials.

[0008] Conventional polymer solid electrolytes such as these were manufactured through a process of forming a coating film and then drying at high temperatures. However, conventional polymer solid electrolyte manufacturing technologies have had limitations in manufacturing polymer solid electrolytes with improved ionic conductivity due to the high crystallinity of crystalline polymers or semi-crystalline polymers. In other words, the higher the crystallinity of the polymer, the lower the chain mobility of the polymer, which restricts the movement of lithium ions within the polymer solid electrolyte, making it difficult to improve the ionic conductivity of the polymer solid electrolyte.

[0009] Accordingly, various methods have been examined to reduce crystallinity by introducing a long chain moiety to the side chain of the polymer or to increase the mobility of the polymer chain by adding a separate plasticizer.

[0010] In addition, in a polymer solid electrolyte including a polymer matrix and a lithium salt, the ionic conductivity of the polymer solid electrolyte was attempted to be improved by controlling the ratio of the polymer matrix and the lithium salt. However, as the content of the lithium salt increased, the mechanical properties of the polymer solid electrolyte deteriorated, making it difficult to manufacture a polymer solid electrolyte in the form of a uniform, thin, free-standing film.

[0011] Meanwhile, to overcome the limitation of manufacturing a polymer solid electrolyte in the form of a thin free-standing film due to the deterioration of mechanical properties, a method of manufacturing a polymer solid electrolyte by directly applying a polymer solution to the surface of an electrode has been proposed, but the issue of side reactions with the electrode has been raised. In particular, when forming a polymer solid electrolyte film by casting a polymer solution onto the lithium metal during the manufacture of an all-solid-state battery using lithium metal as an anode, side reactions between the lithium metal and the polymer solution have become a problem.

[0012] Accordingly, it is necessary to develop a technology for manufacturing a polymer solid electrolyte that can prevent side reactions between the polymer solid electrolyte and the electrode, has high ionic conductivity, and has a uniform thin film form.

[0013] [Prior Art Literature]

[0014] [Patent Document]

[0015] (Patent Document 1) Korean Patent Publication No. 10-2022-0033460

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

[0017] Another object of the present invention is to provide a method for manufacturing a polymer solid electrolyte membrane 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 to a positive electrode or a negative electrode by a transfer process.

[0019] In order to achieve the above purpose, the present invention provides a polymer solid electrolyte membrane in the form of a thin film with a uniform surface,

[0020] A polymer solid electrolyte membrane is provided, wherein the surface roughness (Ra) of one side of the polymer solid electrolyte membrane is 1.00 ㎛ or less.

[0021]

[0022] In one embodiment of the present invention, the polymer solid electrolyte membrane may contain 20 to 100 parts by weight of a lithium salt per 100 parts by weight of a polymer for electrolyte.

[0023] In one embodiment of the present invention, the polymer for electrolyte may include 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.

[0024] In one embodiment of the present invention, the lithium salt is (CF3SO2)2NLi(Lithium bis(trifluoromethanesulphonyl)imide, LiTFSI), (FSO2)2NLi(Lithium bis(fluorosulfonyl)imide, LiFSI), LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN, and LiC(CF3SO2)3.

[0025] In one embodiment of the present invention, the ionic conductivity of the polymer solid electrolyte membrane is 1 x 10 -5 It may be more than S / cm.

[0026]

[0027] The present invention also relates to a method for manufacturing a polymer solid electrolyte membrane, comprising: (S1) a step of applying a solution for forming a polymer solid electrolyte membrane on a release film and then drying it to obtain a polymer solid electrolyte membrane; (S2) a step of positioning and transferring the polymer solid electrolyte membrane on an anode or cathode; and (S3) a step of separating the release film from the polymer solid electrolyte membrane;

[0028] A method for manufacturing a polymer solid electrolyte membrane is provided, wherein the peel strength of the above-mentioned heteromorphic film for the polymer solid electrolyte membrane is 15 gf / 25 mm or less.

[0029] In one embodiment of the present invention, the release film may include 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).

[0030] In one embodiment of the present invention, the drying in step (S1) may be performed by first drying at 20°C to 30°C and then second drying at 90°C to 110°C.

[0031] In one embodiment of the present invention, the solution for forming the polymer solid electrolyte membrane may be prepared by mixing an electrolyte polymer and a lithium salt in a solvent.

[0032] In one embodiment of the present invention, 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.

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

[0034]

[0035] The present invention also provides an all-solid-state battery comprising a positive electrode, a negative electrode, and a polymer solid electrolyte membrane interposed therebetween.

[0036] In one embodiment of the present invention, the surface roughness of one side of the polymer solid electrolyte membrane may be 1.00 ㎛ or less, and an additional film may not be formed due to a side reaction between the other side of the polymer solid electrolyte membrane and the anode or cathode.

[0037] In one embodiment of the present invention, the negative electrode may be a lithium negative electrode.

[0038] The polymer solid electrolyte membrane according to the present invention has the effect of improving surface properties and ionic conductivity due to the transfer process.

[0039] In addition, since it is formed in the form of a polymer solid electrolyte membrane on a heteromorphic film and then transferred to an anode or cathode, there is an effect of preventing side reactions between the polymer solid electrolyte membrane and the anode or cathode.

[0040] In addition, through the process of forming an electrolyte film of a desired size and then transferring it, it is possible to easily form a film larger than the positive or negative electrode, thereby physically blocking internal short circuits, which are the main cause of battery fire.

[0041] Figure 1 shows the results of measuring the ionic conductivity of a polymer solid electrolyte membrane according to changes in the molar ratio of EO and Li ([EO]:[Li]) in the polymer solid electrolyte membrane manufactured using the solution casting process of Comparative Examples 4 to 9.

[0042] Figure 2 shows the results of measuring the ionic conductivity of polymer solid electrolyte membranes manufactured using the transfer process of Examples 1 to 6.

[0043] Figure 3 is a photograph showing the transfer process of Example 3 and Comparative Example 1.

[0044] Figure 4 is a photograph showing the transfer process of Comparative Examples 1 to 3.

[0045] Figure 5 is a photograph showing the transcription process of Example 6.

[0046] Figures 6a to 6c are photographs showing the formation of a polymer solid electrolyte membrane on lithium metal by transfer, solution casting, and freestanding film lamination, respectively.

[0047] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0048] The terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0049] The term “surface roughness” as used herein refers to the degree of micro-roughness on the surface of a polymer solid electrolyte membrane, and is expressed as the arithmetic mean roughness (Ra) value of randomly selected measurements of the micro-roughness formed on the surface of the polymer solid electrolyte membrane. In other words, a larger measured roughness value indicates a rougher surface.

[0050]

[0051] polymer solid electrolyte membrane

[0052] The present invention relates to a polymer solid electrolyte membrane.

[0053] The polymer solid electrolyte membrane according to the present invention is a polymer solid electrolyte membrane in the form of a thin film with a uniform surface, and the surface roughness (Ra) of one side of the polymer solid electrolyte membrane is 1.00 ㎛ or less.

[0054] The above polymer solid electrolyte membrane can be manufactured by a transfer process of forming a polymer solid electrolyte membrane on a release film and then transferring it to an electrode, thereby manufacturing it in the form of a thin film with a uniform surface.

[0055] In addition, the surface roughness (Ra) of the polymer solid electrolyte membrane may be 1.00 ㎛ or less, 0.90 ㎛ or less, 0.80 ㎛ or less, 0.70 ㎛ or less, 0.60 ㎛ or less, 0.50 ㎛ or less, or 0.40 ㎛ or less. If the surface roughness exceeds 1.00 ㎛, contact with the electrode interface may be unstable, which may reduce the lithium ion transfer capability, and if the surface roughness is high, the polymer solid electrolyte membrane may have an uneven surface, which may easily cause lithium dendrites to form, which may increase the possibility of a battery short circuit. The surface roughness may be measured by an optical profiler (OP), an atomic force microscope (AFM), or the like. If the above polymer solid electrolyte membrane is formed directly on the surface of the electrode by a conventional technique such as solution casting, it is not easy to obtain a membrane form due to a side reaction between the polymer solid electrolyte in a solution state and the electrode, and even if a membrane form is obtained, if continuous degradation occurs due to the side reaction between the polymer solid electrolyte and the electrode, it may not be suitable as an electrolyte membrane for maintaining battery performance.

[0056] The polymer solid electrolyte membrane according to the present invention forms a polymer solid electrolyte membrane on a release film and then transfers the polymer solid electrolyte membrane onto an electrode, thereby preventing side reactions between the polymer solid electrolyte in a solution state and the electrode, and thus obtaining a polymer solid electrolyte membrane in the form of a uniform thin film.

[0057] The polymer solid electrolyte membrane formed on the above-described heteromorphic film can be transferred to either the positive or negative electrode. In particular, a lithium negative electrode containing lithium metal is highly reactive, but when the polymer solid electrolyte membrane is formed and then transferred to the lithium negative electrode, side reactions between the polymer solid electrolyte membrane and the lithium negative electrode can be minimized.

[0058]

[0059] In one embodiment of the present invention, the thickness of the polymer solid electrolyte membrane may be 60 μm or less.

[0060] As described above, even when using a polymer with low mechanical properties, it is possible to manufacture a polymer solid electrolyte membrane in a uniform thin film form through a transfer process. Specifically, the thickness of the polymer solid electrolyte membrane may be 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 15 μm or less. The lower limit of the thickness is not particularly limited, and may be, for example, 1 μm or more, 2 μm or more, 3 μm or more, or 5 μm or more.

[0061]

[0062] In one embodiment of the present invention, the polymer solid electrolyte membrane may include an electrolyte polymer and a lithium salt.

[0063]

[0064] In one embodiment of the present invention, the electrolyte polymer may include 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).

[0065] In addition, the weight average molecular weight (Mw) of the polymer for electrolyte may be 300,000 g / mol to 4,000,000 g / mol, specifically, 300,000 g / mol or more, 400,000 g / mol or more, 500,000 g / mol or more, 600,000 g / mol or more, 700,000 g / mol or more, 800,000 g / mol or more, 900,000 g / mol or more, 1,000,000 g / mol or more, 1,100,000 g / mol or more, 1,200,000 g / mol or more, 1,300,000 g / mol or more, 1,400,000 g / mol or more, or 1,500,000 g / mol or more, and 4,000,000 g / mol or less, 3,500,000 g / mol or less, 3,000,000 g / mol or less, 2,500,000 g / mol or less, or 2,000,000 g / mol or less. If the weight average molecular weight (Mw) of the polymer for electrolyte is less than 300,000 g / mol, it may be difficult to obtain a membrane form including an appropriate polymer, and if it exceeds 4,000,000 g / mol, the entanglement of polymer chains in the solution for forming a polymer solid electrolyte membrane used in the manufacturing process increases, the solvent penetration rate into the polymer chains decreases, and accordingly, gelation of the polymer is accelerated, which may lower ionic conductivity. In addition, if the weight average molecular weight (Mw) of the polymer for electrolyte is more than 4,000,000 g / mol, the viscosity increases rapidly during the manufacture of the electrolyte slurry, making it difficult to handle, which may lower the process efficiency.

[0066]

[0067] In one embodiment of the present invention, the lithium salt is (CF3SO2)2NLi(Lithium bis(trifluoromethanesulphonyl)imide, LiTFSI), (FSO2)2NLi(Lithium bis(fluorosulfonyl)imide, LiFSI), LiNO3, LiOH, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, LiSCN and LiC(CF3SO2)3. Preferably, the lithium salt may be (CF3SO2)2NLi(Lithium bis(trifluoromethanesulphonyl)imide, LiTFSI).

[0068] In addition, in the polymer solid electrolyte membrane, the lithium salt may be included in an amount of 20 to 100 parts by weight based on 100 parts by weight of the polymer solid electrolyte. If the content of the lithium salt is less than 20 parts by weight, the crystallinity of the polymer may not be suppressed, which may lower the ionic conductivity of the polymer solid electrolyte membrane. If it exceeds 100 parts by weight, the crystallinity of the polymer may be lowered, which may lower the mechanical properties of the polymer solid electrolyte membrane. In addition, if the content of the lithium salt is present in an excessive amount exceeding 100 parts by weight, aggregates may be formed in the electrolyte, which may interfere with ion transfer, and ultimately the performance of the electrolyte membrane may be lowered. Specifically, the content of the lithium salt may 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 may be 85 parts by weight or less, 90 parts by weight or less, or 100 parts by weight or less.

[0069]

[0070] In one embodiment of the present invention, the polymer solid electrolyte membrane may include polyethylene oxide (PEO) and a lithium salt, and the molar ratio of ethylene oxide (EO), which is a repeating unit of the PEO, to lithium (Li) of the lithium salt ([EO]:[Li]) may be 7:1 to 15:1. If the molar ratio of ethylene oxide to lithium ([EO]:[Li]) is less than 7:1, the content of the polymer for electrolyte may decrease, thereby deteriorating the mechanical properties of the polymer solid electrolyte, and if it exceeds 15:1, the content of the lithium salt may decrease, thereby deteriorating the ionic conductivity of the polymer solid electrolyte membrane. Specifically, the molar ratio of ethylene oxide to lithium ([EO]:[Li]) 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 repeating units of polymers other than PEO and lithium may also be within the above range.

[0071]

[0072] In one embodiment of the present invention, the ionic conductivity of the polymer solid electrolyte membrane is 1 x 10 -5 S / cm or more, 2 x 10 -5 S / cm or more or 3 x 10 -5 It can be more than S / cm. The higher the ionic conductivity value within the above range, the more advantageous it is. The upper limit of the ionic conductivity is not particularly limited, but, for example, 5 x 10 -5 S / cm or less or 6 x 10 -5 It may be less than S / cm.

[0073]

[0074] In one embodiment of the present invention, the polymer solid electrolyte membrane can be easily manufactured to have a larger size than the positive electrode or the negative electrode. Since the polymer solid electrolyte membrane is not formed directly on the positive electrode or the negative electrode, but rather a uniform thin film polymer solid electrolyte is first manufactured and then transferred to the positive electrode or the negative electrode, a polymer solid electrolyte membrane having a larger size than the positive electrode or the negative electrode can be easily manufactured, and contact between the positive electrode and the negative electrode can be prevented, thereby preventing an internal short circuit.

[0075]

[0076] In general, polymer electrolytes, such as polyethylene oxide, have high crystallinity, making it difficult to manufacture high-ionic conductivity polymer solid electrolyte membranes using polyethylene oxide as a raw material. However, attempts have been made to overcome this limitation by lowering the crystallinity of polyethylene oxide. However, when lowering the crystallinity of polyethylene oxide to manufacture a thin-film electrolyte membrane, the deterioration of mechanical properties makes it difficult to manufacture a uniform thin-film electrolyte membrane. Therefore, by introducing a transfer process, it is possible to manufacture a polymer solid electrolyte membrane with high ionic conductivity even when using an electrolyte polymer such as polyethylene oxide as a raw material. Furthermore, using a transfer process can manufacture an electrolyte membrane with an area larger than that of the substrate, which has the advantage of physically preventing internal short circuits that can cause battery fires when the positive and negative electrodes meet.

[0077]

[0078] The polymer solid electrolyte membrane as described above can be manufactured as a free-standing film in the form of a uniform thin film by a transfer process.

[0079]

[0080] Method for manufacturing polymer solid electrolyte membrane

[0081] The present invention also relates to a method for producing a polymer solid electrolyte membrane.

[0082] The method for manufacturing a polymer solid electrolyte membrane according to the present invention comprises the steps of (S1) applying a solution for forming a polymer solid electrolyte membrane on a release film and then drying the solution to obtain a polymer solid electrolyte membrane; (S2) transferring the polymer solid electrolyte membrane by positioning it on an anode or cathode; and (S3) separating the release film from the polymer solid electrolyte membrane; wherein the peel strength of the release film with respect to the polymer solid electrolyte membrane may be 15 gf / 25 mm or less.

[0083]

[0084] Hereinafter, the method for manufacturing a polymer solid electrolyte membrane according to the present invention will be described in more detail step by step. The properties and contents of the raw materials used in the manufacturing method are as described above.

[0085]

[0086] In one embodiment of the present invention, in the step (S1), a solution for forming a polymer solid electrolyte membrane is applied onto a release film and then dried to obtain a polymer solid electrolyte membrane.

[0087] The peel strength of the above release film with respect to the polymer solid electrolyte membrane may be 15 gf / 25 mm or less. If the peel strength exceeds 15 gf / 25 mm, it may be difficult to separate the release film from the polymer solid electrolyte membrane, and thus the transfer process may not proceed smoothly. Specifically, the peel strength may be 15 gf / 25 mm or less, 13 gf / 25 mm or less, 10 gf / 25 mm or less, 8 gf / 25 mm or less, or 5 gf / 25 mm or less. The lower limit of the peel strength is not particularly limited, and may be, for example, 0.5 gf / 25 mm or more.

[0088] In addition, when the peel strength of the above-mentioned release film is within the above range, the surface roughness of the polymer solid electrolyte formed by removing the above-mentioned release film can be manufactured in the form of a uniform thin film of 1.00 ㎛ or less.

[0089]

[0090] In addition, the release film is not particularly limited as long as it satisfies the peel strength as described above. For example, the release film may include 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).

[0091] In addition, the thickness of the release film is not particularly limited, but may be 10 ㎛ to 100 ㎛ for the convenience of the process. If the thickness of the release film is less than 10 ㎛, the surface roughness of the solid electrolyte membrane formed thereon may also become rough due to the difference in surface roughness of the release film, and the release film may be cut or broken during the process. If the thickness of the release film exceeds 100 ㎛, the release film may be too thick and heavy, which may cause problems such as sagging during the process. Specifically, the thickness of the release film may be 10 ㎛ or more, 20 ㎛ or more, 30 ㎛ or more, or 40 ㎛ or more, and may be 100 ㎛ or less, 90 ㎛ or less, 80 ㎛ or less, 70 ㎛ or less, or 60 ㎛ or less.

[0092] The above polymer solid electrolyte membrane forming solution may be prepared by mixing an electrolyte polymer and a lithium salt in a solvent. The types and weights of the electrolyte polymer and lithium salt are as described above.

[0093] In addition, the concentration of the polymer solid electrolyte membrane forming solution can be appropriately adjusted in consideration of the degree to which the coating process can proceed smoothly when coating the polymer solid electrolyte membrane forming solution on the release film. For example, the concentration of the polymer solid electrolyte membrane forming solution can be such that the concentration of the electrolyte polymer in the solution is 3% to 10%, and specifically, it can be 3% or more, 4% or more, or 5% or more, and 6% or less, 8% or less, or 10% or less. If the concentration of the polymer solid electrolyte membrane forming solution is less than 3%, the concentration is too dilute and may flow when coated on the release film, and if it exceeds 10%, it is difficult to dissolve a desired amount of lithium salt in the solution, and the viscosity may be high, making it difficult to coat in the form of a uniform thin film.

[0094] In addition, the solvent is not particularly limited 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.

[0095] In addition, the coating method is not particularly limited as long as it is a method that can uniformly coat the polymer solid electrolyte membrane forming solution on the release 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, or solution casting.

[0096]

[0097] The above drying may be performed by first drying at 20°C to 40°C, followed by second drying at 80°C to 120°C. In the first drying, the solvent is removed, and in the second drying, the mechanical properties of the polymer solid electrolyte membrane can be strengthened.

[0098] In addition, the temperature during the primary drying may be 20°C or higher, 21°C or higher, or 22°C or higher, and 30°C or lower, 35°C or lower, or 40°C or lower. If the temperature during the primary drying is lower than 20°C, the solvent of the polymer solid electrolyte membrane may not be removed as much as desired, and if it exceeds 40°C, the evaporation rate of the solvent may be excessively accelerated, creating a crater-like shape on the surface of the electrolyte membrane, which may increase surface roughness.

[0099] In addition, the temperature during the secondary drying may be 80°C or higher, 85°C or higher, or 90°C or higher, and 100°C or lower, 115°C or lower, or 120°C or lower. If the temperature during the secondary drying is lower than 80°C, the shape of the film may not be formed, and if it exceeds 120°C, the electrolyte polymer or lithium salt included in the film may be denatured, resulting in a decrease in physical properties such as ionic conductivity.

[0100]

[0101] In one embodiment of the present invention, in step (S2), the polymer solid electrolyte membrane may be positioned and transferred on an anode or cathode. At this time, a side of the polymer solid electrolyte membrane other than the side in contact with the release film may be positioned on the anode or cathode.

[0102] The above transfer can be performed by positioning the polymer solid electrolyte membrane on the anode or cathode and then using a tool such as a roll to adhere the polymer solid electrolyte membrane to the interface of the anode or cathode. Since the polymer solid electrolyte membrane itself has sticky properties, transfer is easily possible without a process of applying high pressure.

[0103]

[0104] In addition, since the polymer solid electrolyte membrane is transferred to the anode or cathode after being formed in the form of a membrane on the release film, side reactions between the polymer solid electrolyte membrane and the anode or cathode can be prevented. If a polymer solid electrolyte membrane forming solution is applied to the anode or cathode to directly form a membrane, a side reaction may occur between the raw material existing in a state of high freedom in the solution and the anode or cathode, which may deteriorate the interface characteristics of the anode or cathode, or an additional membrane may be formed due to the side reaction.

[0105] In addition, among the negative electrodes, the reactivity of lithium in a lithium negative electrode containing lithium metal is high, but if the polymer solid electrolyte membrane is transferred onto the lithium negative electrode using a transfer process, side reactions can be prevented.

[0106]

[0107] In one embodiment of the present invention, in the step (S3), the heterogeneous film can be removed from the polymer solid electrolyte membrane.

[0108] When the polymer solid electrolyte membrane is attached to the anode or cathode in the above step (S2), the release film can be removed to complete the transfer process.

[0109]

[0110] All-solid-state batteries

[0111] The present invention also relates to an all-solid-state battery including the polymer solid electrolyte, wherein the all-solid-state battery includes a cathode, an anode, and a polymer solid electrolyte membrane interposed between the cathode and the anode, wherein the polymer solid electrolyte membrane has the characteristics described above.

[0112]

[0113] In one embodiment of the present invention, the surface roughness of one side of the polymer solid electrolyte membrane may be 1.00 ㎛ or less, and an additional film may not be formed due to a side reaction between the other side of the polymer solid electrolyte membrane and the anode or cathode.

[0114] Since the above polymer solid electrolyte membrane is formed in the form of a membrane on a release film and then transferred onto an anode or cathode, one side of the polymer solid electrolyte membrane from which the release film is removed after transfer has uniform surface characteristics.

[0115] Accordingly, side reactions can be prevented between the polymer solid electrolyte membrane and the positive or negative electrode, and they can be in a state of simple physical contact.

[0116] Furthermore, since side reactions are prevented at the interface between the polymer solid electrolyte membrane and the anode or cathode, no additional membrane is formed due to side reactions. If side reactions occur, the electrolyte membrane is continuously consumed, potentially leading to reduced battery performance. Suppressing side reactions allows for the production of stable batteries with no performance degradation.

[0117] In particular, the negative electrode may be a lithium negative electrode, and side reactions may be prevented even between the negative electrode including highly reactive lithium metal and the polymer solid electrolyte membrane.

[0118]

[0119] In one embodiment of 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.

[0120] The above positive electrode active material layer includes a positive electrode active material, a binder, and a conductive material.

[0121] In addition, the positive electrode active material is not particularly limited as long as it is a material capable of reversibly absorbing and releasing lithium ions, and examples thereof include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and Li[Ni x Co y Mn z M v ]O2 (wherein M is one or two or more elements selected from the group consisting of Al, Ga, and In; 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 c (In the above formula, 0≤a≤0.2, 0.6≤b≤1, 0≤b'≤0.2, 0≤c≤0.2; M includes at least one selected from the group consisting of Mn and Ni, Co, Fe, Cr, V, Cu, Zn and Ti; M' is at least one selected from the group consisting of Al, Mg and B, and A is at least one selected from the group consisting of P, F, S and N.) layered compounds or compounds substituted with one or more transition metals; chemical formula Li 1+y Mn 2-yLithium manganese oxides such as O4 (where y is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5, Cu2V2O7; chemical formula LiNi 1-y Ni-site type lithium nickel oxide represented by MyO2 (wherein, M=Co, Mn, Al, Cu, Fe, Mg, B or Ga, and y is 0.01 to 0.3); chemical formula LiMn 2-y M y Lithium manganese composite oxides represented by O2 (wherein M is Co, Ni, Fe, Cr, Zn or Ta, and y is 0.01 to 0.1) or Li2Mn3MO8 (wherein M is Fe, Co, Ni, Cu or Zn); LiMn2O4 in which a portion of Li in the chemical formula is replaced by an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, etc., but are not limited thereto.

[0122] In addition, the positive electrode active material may be included in an amount of 40 to 80 wt% based on the total weight of the positive electrode active material layer. Specifically, the content of the positive electrode active material may be 40 wt% or more or 50 wt% or more, and 70 wt% or less or 80 wt% or less. If the content of the positive electrode active material is less than 40 wt%, 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 wt%, the mass transfer resistance may increase.

[0123]

[0124] In addition, the binder is a component that assists in the bonding of the positive electrode active material and the conductive material and the bonding to the current collector, and includes styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile copolymer, acrylonitrile-butadiene rubber, nitrile butadiene rubber, acrylonitrile-styrene-butadiene copolymer, acrylic rubber, butyl rubber, fluorine rubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene / propylene copolymer, polybutadiene, polyethylene oxide, chlorosulfonated polyethylene, polyvinylpyrrolidone, polyvinylpyridine, polyvinyl alcohol, polyvinyl acetate, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, latex, acrylic resin, phenol resin, epoxy resin, carboxymethylcellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate The binder may include at least one selected from the group consisting of butyrate, cellulose acetate propionate, cyanoethylcellulose, cyanoethylsucrose, 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 at least one selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethylcellulose, polyacrylic acid, lithium polyacrylate, and polyvinylidene fluoride.

[0125] In addition, the binder may be included in an amount of 1 wt% to 30 wt% based on the total weight of the positive electrode active material layer, and specifically, the content of the binder may be 1 wt% or more or 3 wt% or more, and 15 wt% or less or 30 wt% or less. If the content of the binder is less than 1 wt%, the adhesive strength between the positive electrode active material and the positive electrode current collector may be reduced, and if it exceeds 30 wt%, the adhesive strength may be improved, but the content of the positive electrode active material may be reduced, which may lower the battery capacity.

[0126]

[0127] In addition, the conductive material is not particularly limited as long as it prevents side reactions in the internal environment of the all-solid-state battery, does not cause chemical changes in the battery, and has excellent electrical conductivity. Representative examples thereof include graphite or conductive carbon, and examples thereof include graphite such as natural graphite and 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 having a crystal structure of graphene or graphite; conductive fibers such as carbon fiber and metal fiber; fluorinated carbon; metal powder such as 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; which may be used alone or in combination of two or more thereof, but are not necessarily limited thereto.

[0128] The conductive material may typically be included in an amount of 0.5 wt% to 30 wt% based on the total weight of the positive electrode active material layer, and specifically, the content of the conductive material may be 0.5 wt% or more or 1 wt% or more, and 20 wt% or less or 30 wt% or less. If the content of the conductive material is too low, such as less than 0.5 wt%, it may be difficult to expect an effect of improving electrical conductivity or the electrochemical characteristics of the battery may deteriorate, and if it exceeds 30 wt%, the amount of the positive electrode active material may be relatively small, which may lower the capacity and energy density. The method of including the conductive material in the positive electrode is not particularly limited, and a conventional method known in the art, such as coating on the positive electrode active material, may be used.

[0129]

[0130] In addition, the positive electrode current collector supports the positive electrode active material layer and serves to transfer electrons between the external conductor and the positive electrode active material layer.

[0131] The positive electrode current collector is not particularly limited as long as it has high electronic conductivity without causing chemical changes in the all-solid-state battery. For example, the positive electrode current collector may be copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, silver, etc., or an aluminum-cadmium alloy.

[0132] The above-mentioned positive electrode current collector may have a finely irregular structure on its surface or may employ a three-dimensional porous structure to strengthen the bonding strength with the positive electrode active material layer. Accordingly, the positive electrode current collector may include various forms such as a film, sheet, foil, mesh, net, porous body, foam, or non-woven fabric.

[0133] The positive electrode as described above can be manufactured according to a conventional method, and specifically, a composition for forming a positive electrode active material layer prepared by mixing a positive electrode active material, a conductive agent, and a binder in an organic solvent phase is applied and dried on a positive electrode current collector, and optionally, to improve electrode density, it can be manufactured by compression molding the positive electrode current collector. At this time, it is preferable to use an organic solvent that can uniformly disperse the positive electrode active material, binder, and conductive agent and is easily evaporated. Specifically, examples thereof include acetonitrile, methanol, ethanol, tetrahydrofuran, water, isopropyl alcohol, and the like.

[0134]

[0135] In one embodiment of 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 may be formed on one surface of a negative electrode current collector.

[0136] The above negative active material is lithium (Li + ) can be reversibly intercalated or deintercalated, a material that can react with lithium ions to form a reversibly lithium-containing compound, or a lithium metal or a lithium alloy.

[0137] The above lithium ion (Li + ) can be reversibly inserted or de-inserted, for example, crystalline carbon, amorphous carbon, or a mixture thereof. The lithium ion (Li +) can be, for example, tin oxide, titanium nitrate or silicon. The lithium alloy can be, 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).

[0138] Preferably, the negative active material may be lithium metal, and specifically, may be in the form of a lithium metal thin film or lithium metal powder.

[0139] The negative electrode active material may be included in an amount of 40 to 80 wt% based on the total weight of the negative electrode active material layer. Specifically, the content of the negative electrode active material may be 40 wt% or more or 50 wt% or more, and 70 wt% or less or 80 wt% or less. If the content of the negative electrode active material is less than 40 wt%, 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 wt%, the material transfer resistance may increase.

[0140] In addition, the binder is as described above in the positive electrode active material layer.

[0141] In addition, the above-described conductive material is as described above in the positive electrode active material layer.

[0142] In addition, the negative electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery. For example, the negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., an aluminum-cadmium alloy, etc. In addition, the negative electrode current collector, like the positive electrode current collector, may be made of various forms such as a film, sheet, foil, net, porous body, foam, non-woven fabric, etc. having fine irregularities formed on the surface.

[0143] The method for manufacturing the above negative electrode is not particularly limited, and can be manufactured by forming a negative electrode active material layer on the negative electrode current collector using a method for forming a layer or film commonly used in the art. For example, methods such as compression, coating, and deposition can be used. In addition, a case in which a battery is assembled on the negative electrode current collector without a lithium thin film and then a metallic lithium thin film is formed on the metal plate through initial charging is also included in the negative electrode of the present invention.

[0144]

[0145] In addition, 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.

[0146]

[0147] At this time, specific examples of the device include, but are not limited to, a power tool that is powered by an electric motor; an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), etc.; an electric two-wheeled vehicle including an electric bicycle (E-bike) and an electric scooter (E-scooter); an electric golf cart; and a power storage system.

[0148] Hereinafter, preferred examples are presented to help understand the present invention, but the following examples are only illustrative of the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present invention, and it is also natural that such changes and modifications fall within the scope of the appended patent claims.

[0149] In the following examples and comparative examples, polymer solid electrolyte membranes and all-solid-state batteries were manufactured according to the composition, type of release film, and process as described in Table 1 below.

[0150]

[0151] Polymer for electrolyte (PEO, parts by weight) Lithium salt (LiTFSI, parts by weight) [EO]:[Li] Polymer solid electrolyte membrane thickness (㎛) Peel strength of release film (gf / mm) Process Example 1 100 8 1.38:112 12 Transfer Example 2 100 8 1.38:127 12 Transfer Example 3 100 8 1.38:137 12 Transfer Example 4 100 8 1.38:145 12 Transfer Example 5 100 8 1.38:151 12 Transfer Example 6 100 8 1.38:140 2 Transfer Example 7 100 8 1.38:150 4.2 Transfer Example 8 100 8 1.38:150 7.7 Transfer Example 910081.38:15010.7 Transcription comparison example 110081.38:11218 Transcription comparison example 210081.38:112455 Transcription comparison example 310081.38:112600 Transcription comparison example 410032.720:1100-Solution casting comparison example 510040.716:1100-Solution casting comparison example 610054.312:1100-Solution casting comparison example 710081.38:1100-Solution casting comparison example 8100108.76:1100-Solution casting comparison example 9100130.34:1100-Solution casting comparison example 1010081.38:13812 Freestanding

[0152]

[0153] Example 1

[0154] Polyethylene oxide (Mw: 600K g / mol, Sigma Aldrich), a polymer for electrolyte, and LiTFSI, a lithium salt, were mixed in acetonitrile, a solvent, to prepare a polymer solid electrolyte forming solution. The mixing was performed by magnetic stirring at 90°C for 24 hours. At this time, the solution was prepared so that the concentration of polyethylene oxide contained in the solution was 5.8%.

[0155] The above polymer solid electrolyte membrane forming solution was applied to a release film A (Peel strength: 12 gf / 25 mm, thickness: 38 ㎛) and solution casted, followed by primary drying at room temperature for 12 hours and secondary drying at 100°C for 12 hours to form a polymer solid electrolyte membrane having a thickness of 12 ㎛. The polymer solid electrolyte membrane was transferred to a stainless steel (SS) substrate of a coin cell, and the release film was removed to assemble the coin cell.

[0156]

[0157] Example 2

[0158] A polymer solid electrolyte membrane and a coin cell were manufactured in the same manner as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 27 μm.

[0159]

[0160] Example 3

[0161] A polymer solid electrolyte membrane and a coin cell were manufactured in the same manner as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 37 μm.

[0162]

[0163] Example 4

[0164] A polymer solid electrolyte membrane and a coin cell were manufactured in the same manner as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 45 μm.

[0165]

[0166] Example 5

[0167] A polymer solid electrolyte membrane and a coin cell were manufactured in the same manner as in Example 1, except that the thickness of the polymer solid electrolyte membrane was 51 μm.

[0168]

[0169] Example 6

[0170] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that a polymer solid electrolyte membrane B (Peel strength: 2 gf / 25 mm, thickness: 78 ㎛) was used instead of a polymer solid electrolyte membrane A and the thickness of the polymer solid electrolyte membrane was 40 ㎛.

[0171]

[0172] Example 7

[0173] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that a polymer solid electrolyte membrane F (Peel strength: 4.2 gf / 25 mm, thickness: 50 ㎛) was used instead of a polymer solid electrolyte membrane A and the thickness of the polymer solid electrolyte membrane was 50 ㎛.

[0174]

[0175] Example 8

[0176] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that a polymer solid electrolyte membrane G (Peel strength: 7.7 gf / 25 mm, thickness: 78 ㎛) was used instead of a polymer solid electrolyte membrane A and the thickness of the polymer solid electrolyte membrane was 50 ㎛.

[0177]

[0178] Example 9

[0179] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that a polymer solid electrolyte membrane H (Peel strength: 10.7 gf / 25 mm, thickness: 76 ㎛) was used instead of a polymer solid electrolyte membrane A and the thickness of the polymer solid electrolyte membrane was 50 ㎛.

[0180]

[0181] Comparative Example 1

[0182] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that release film C (Peel strength: 18 gf / 25 mm, thickness: 50 ㎛) was used instead of release film A.

[0183]

[0184] Comparative Example 2

[0185] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that release film D (Peel strength: 455 gf / 25 mm, thickness: 78 ㎛) was used instead of release film A.

[0186]

[0187] Comparative Example 3

[0188] A polymer solid electrolyte membrane and coin cell were manufactured in the same manner as in Example 1, except that release film E (Peel strength: 600 gf / 25 mm, thickness: 39 ㎛) was used instead of release film A.

[0189]

[0190] Comparative Example 4

[0191] Instead of casting the solution for forming a polymer solid electrolyte film of Example 1 onto the release film A, the solution was cast onto a stainless steel (SS) substrate, which is the lower substrate of the coin cell, and then dried at room temperature for 12 hours and then dried at 100°C for 12 hours to form a polymer solid electrolyte film having a thickness of 100 μm.

[0192]

[0193] Comparative Example 5

[0194] In preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) of the polyethylene oxide and lithium (Li) of the lithium salt ([EO] / [Li]) was set to 16:1, and 40.7 parts by weight of the LiTFSI was mixed with 100 parts by weight of the polyethylene oxide, and a polymer solid electrolyte membrane and a coin cell were prepared in the same manner as in Comparative Example 4.

[0195]

[0196] Comparative Example 6

[0197] In preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) of the polyethylene oxide and lithium (Li) of the lithium salt ([EO] / [Li]) was set to 12:1, and 54.3 parts by weight of the LiTFSI was mixed with 100 parts by weight of the polyethylene oxide, and a polymer solid electrolyte membrane and a coin cell were prepared in the same manner as in Comparative Example 4.

[0198]

[0199] Comparative Example 7

[0200] In preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) of the polyethylene oxide and lithium (Li) of the lithium salt ([EO] / [Li]) was set to 8:1, and 81.3 parts by weight of the LiTFSI was mixed with 100 parts by weight of the polyethylene oxide, and a polymer solid electrolyte membrane and a coin cell were prepared in the same manner as in Comparative Example 4.

[0201]

[0202] Comparative Example 8

[0203] In preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) of the polyethylene oxide and lithium (Li) of the lithium salt ([EO] / [Li]) was set to 6:1, and 108.7 parts by weight of the LiTFSI was mixed with 100 parts by weight of the polyethylene oxide, and a polymer solid electrolyte membrane and a coin cell were prepared in the same manner as in Comparative Example 4.

[0204]

[0205] Comparative Example 9

[0206] In preparing the polymer solid electrolyte solution of Example 1, the molar ratio of ethylene oxide (EO) of the polyethylene oxide and lithium (Li) of the lithium salt ([EO] / [Li]) was set to 4:1, and 130.3 parts by weight of the LiTFSI was mixed with 100 parts by weight of the polyethylene oxide, and a polymer solid electrolyte membrane and a coin cell were prepared in the same manner as in Comparative Example 4.

[0207]

[0208] Comparative Example 10

[0209] A polymer solid electrolyte membrane was formed on a release film in the same manner as in Example 1 except that the thickness was 38 μm, and then the dried polymer solid electrolyte membrane was separated from the release film to manufacture a freestanding thin film polymer solid electrolyte membrane without a support.

[0210]

[0211] Experimental Example 1: Measurement of the ionic conductivity of a polymer solid electrolyte membrane

[0212] In order to measure the ionic conductivity of the polymer solid electrolyte membrane manufactured in the examples and comparative examples, the polymer solid electrolyte membrane was punched into a circle with a size of 1.7671㎠, and the punched polymer solid electrolyte was placed between two sheets of stainless steel (SS) to manufacture a coin cell.

[0213] The resistance was measured at 25°C using an electrochemical impedance spectrometer (EIS, VM3, Bio Logic Science Instrument) with an amplitude of 10 mV and a scan range of 500 KHz to 20 MHz, and then the ionic conductivity of the polymer solid electrolyte membrane was calculated using Equation 1 below.

[0214] [Formula 1]

[0215]

[0216] In the above equation 1, σ i 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 the electrochemical impedance spectrometer, L is the thickness (㎛) of the polymer solid electrolyte membrane, and A is the area (cm) of the polymer solid electrolyte membrane. 2 ) means.

[0217]

[0218] Figure 1 and Table 2 below show the results of measuring the ionic conductivity of a polymer solid electrolyte membrane according to changes in the molar ratio of EO and Li ([EO]:[Li]) in the polymer solid electrolyte membrane manufactured using a solution casting process.

[0219]

[0220] [EO]:[Li]σ i (S / cm) Comparative example 420: 14.2 x 10 -7 Comparative Example 516: 17.4 x 10 -7 Comparative Example 612: 13.8 x 10 -6 Comparative Example 78: 11.2 x 10 -5 Comparative Example 86: 11.9 x 10 -6 Comparative Example 94: 11.7 x 10 -6

[0221]

[0222] As shown in Fig. 1 and Table 2 above, in the polymer solid electrolyte membrane manufactured by solution casting, it was confirmed that the ionic conductivity of the polymer solid electrolyte membrane was the highest when [EO]:[Li] = 8:1 as in Comparative Example 7.

[0223]

[0224] Figure 2 and Table 3 below show the results of measuring the ionic conductivity of a polymer solid electrolyte membrane manufactured using a transfer process.

[0225] The polymer solid electrolyte membranes of Examples 1 to 9 below all have [EO]:[Li] = 8:1, which corresponds to the [EO]:[Li] ratio in Table 1 above where the ionic conductivity of the polymer solid electrolyte membrane can be excellent.

[0226]

[0227] [EO]:[Li] Peel Strength (gf / 25 mm)σ i (S / cm) Example 18: 1121.35 x 10 -5 Example 28:1122.44 x 10 -5 Example 38:1122.66 x 10 -5 Example 48:1122.55 x 10 -5 Example 58:1121.51 x 10 -5 Example 68:123.77 x 10 -5 Example 78:14.22.48 x 10 -5 Example 88:17.72.20 x 10 -5 Example 98:110.71.84 x 10 -5

[0228]

[0229] Referring to FIG. 2 and Table 3 above, it can be seen that the ionic conductivity of Example 6 is high. The release film used in Example 6 has a Peel Strength of 2 gf / 25 mm, which is lower than the Peel Strength of 12 gf / 25 mm of the release films used in Examples 1 to 5. From this, it can be seen that when the Peel Strength of the release film used in the transfer process when manufacturing a polymer solid electrolyte membrane is low, the electrolyte membrane and the release film are easily separated, and deformation such as breakage or stretching is suppressed, reducing process issues and showing high ionic conductivity.

[0230]

[0231] Experimental Example 2: Confirming the feasibility of the transcription process

[0232] The transfer processes of Example 3, Comparative Examples 1 and 2 were visually confirmed. The peel strengths of the release films used in the transfer processes of Example 3, Comparative Examples 1 and 2 were 12 gf / 25 mm, 18 gf / 25 mm and 455 gf / 25 mm, respectively.

[0233]

[0234] Figure 3 is a photograph observing whether the transfer process of Example 3 and Comparative Example 1 is feasible. When manufacturing a polymer solid electrolyte membrane, the feasibility of the transfer process is observed according to the peel strength of the release film used in the transfer process.

[0235] Referring to FIG. 3, Comparative Example 1 showed that the Peel Strength of the release film used in the transfer process was relatively greater than that of Example 1, so that the release film (10) was not released from the polymer solid electrolyte membrane (20), and when an external force was applied to separate the release film and the solid electrolyte membrane, damage and deformation of the membrane occurred. This shows that a release film having a Peel Strength of 18 gf / 25 mm or more is not capable of the transfer process.

[0236]

[0237] Figure 4 is a photograph observing the transfer process of Comparative Examples 1 to 3.

[0238] Referring to Fig. 4, it was confirmed that when the peel strength of the release film used in the transfer process is large, the release film (10) is not separated from the polymer solid electrolyte membrane (20), so that the membrane is deformed during transfer, or the polymer solid electrolyte membrane (20) is difficult to transfer onto the lithium negative electrode (30).

[0239] Since the Peel Strength of the release film (10) used in the transfer process of Comparative Example 1, Comparative Example 2, and Comparative Example 3 is 18 gf / 25 mm, 455 gf / 25 mm, and 600 gf / 25 mm, respectively, it can be seen that the Peel Strength of the release film should be less than this.

[0240]

[0241] Figure 5 is a photograph showing the transfer process when manufacturing a polymer solid electrolyte membrane of Example 6.

[0242] Referring to FIG. 5, it can be confirmed that the polymer solid electrolyte membrane (20) formed on the release film (10) is easily released from the release film (10) (a). By utilizing this characteristic, the polymer solid electrolyte membrane (20) can be transferred to the surface of the lithium negative electrode (30) to be transferred, and by removing the release film (10) on one side of the polymer solid electrolyte membrane (20) (b), a polymer solid electrolyte membrane (20) in a state of being combined with the lithium negative electrode (30) can be obtained (c).

[0243]

[0244] Experimental Example 3: Surface Roughness Measurement

[0245] In order to measure the surface roughness of the polymer solid electrolyte membranes of Example 6 and Comparative Example 7 manufactured by the transfer process and solution casting, respectively, the polymer solid electrolyte membranes manufactured in Example 6 and Comparative Example 7 were sampled in a square size of 1 ㎠ and fixed with carbon tape on a surface roughness measuring holder while attached to a release film.

[0246] The surface roughness of a 2D plane was measured at room temperature using a 3D optical profiler (OP, NV-F2700, Nano System) in WSI mode with a width of 0.5 mm x a length of 0.5 mm, and Ra, which represents the surface roughness, was obtained.

[0247] The polymer solid electrolyte membrane of Comparative Example 7 manufactured by the solution casting method had an Ra of 1.3 ㎛ or more, and the polymer solid electrolyte membrane of Example 6 manufactured by the transfer method was measured to have an Ra of less than 0.4 ㎛.

[0248] Therefore, it was confirmed that the polymer solid electrolyte membrane of the transfer method has more uniform and smoother surface roughness characteristics than that of the solution casting method.

[0249]

[0250] Experimental Example 4: Confirmation of the Occurrence of Side Reactions Between Polymer Solid Electrolyte Membranes and Lithium Metal

[0251] The polymer solid electrolyte membrane of Example 1 was transferred onto lithium metal, and the occurrence of a side reaction between the polymer solid electrolyte membrane and the lithium metal was observed.

[0252] In addition, the solution for forming a polymer solid electrolyte membrane of Comparative Example 4 was solution-casted onto lithium metal to form a polymer solid electrolyte membrane, and the occurrence of a side reaction between the polymer solid electrolyte membrane and the lithium metal was observed.

[0253] Additionally, the free-standing polymer solid electrolyte membrane of Comparative Example 10 was laminated to lithium metal.

[0254]

[0255] Figures 6a to 6c are photographs showing the formation of a polymer solid electrolyte film on a lithium metal by transfer, solution casting, and pre-standing film lamination, respectively.

[0256] As a result, as shown in Fig. 6a, in Example 1, it was confirmed that the polymer solid electrolyte membrane was transferred onto lithium metal and the polymer solid electrolyte membrane was maintained without additional side reactions.

[0257] On the other hand, as shown in Fig. 6b, when a polymer solid electrolyte membrane was formed on a lithium metal by solution casting in Comparative Example 4, it was found that a side reaction occurred between the solution for forming the polymer solid electrolyte membrane and the lithium metal, so that the polymer solid electrolyte membrane could not be formed normally.

[0258] In addition, as shown in Fig. 6c, it was found that the freestanding polymer solid electrolyte membrane manufactured in Comparative Example 10 was deformed from the moment it was separated from the release film, and that folding and pushing occurred on the lithium metal, so that it could not even be laminated normally.

[0259]

[0260] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0261]

[0262] [Explanation of symbols]

[0263] 10: Lee Hyung Film

[0264] 20: Polymer solid electrolyte membrane

[0265] 30: Lithium cathode

Claims

1. A polymer solid electrolyte membrane in the form of a thin film with a uniform surface, A polymer solid electrolyte membrane, wherein the surface roughness (Ra) of one side of the polymer solid electrolyte membrane is 1.00 ㎛ or less.

2. In paragraph 1, A polymer solid electrolyte membrane, wherein the polymer solid electrolyte membrane contains 20 to 100 parts by weight of a lithium salt per 100 parts by weight of a polymer for electrolyte.

3. In paragraph 2, A polymer solid electrolyte membrane, wherein 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 derivatives thereof.

4. In paragraph 2, The above lithium salt is (CF 3 SO 2 ) 2 NLi(Lithium bis(trifluoromethanesulphonyl)imide, LiTFSI), (FSO 2 ) 2 NLi(Lithium bis(fluorosulfonyl)imide, LiFSI), 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 and LiC(CF 3 SO 2 ) 3 A polymer solid electrolyte membrane comprising at least one selected from the group consisting of:

5. In paragraph 1, The ionic conductivity of the above polymer solid electrolyte membrane is 1 x 10 -5 A polymer solid electrolyte membrane having a density of S / cm or greater.

6. (S1) A step of applying a solution for forming a polymer solid electrolyte membrane on a heteromorphic film and then drying it to obtain a polymer solid electrolyte membrane; (S2) a step of transferring the polymer solid electrolyte membrane by positioning it on an anode or cathode; and (S3) A step of separating a heterogeneous film from the polymer solid electrolyte membrane; including, A method for manufacturing a polymer solid electrolyte membrane, wherein the peel strength of the release film for the polymer solid electrolyte membrane is 15 gf / 25 mm or less.

7. In paragraph 6, A method for manufacturing a polymer solid electrolyte membrane, wherein the above-mentioned 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. In paragraph 6, A method for manufacturing a polymer solid electrolyte membrane, wherein the drying in the step (S1) is performed firstly at 20°C to 30°C and then secondly at 90°C to 110°C.

9. In paragraph 6, A method for producing a polymer solid electrolyte membrane, wherein the above polymer solid electrolyte membrane forming solution is produced by mixing an electrolyte polymer and a lithium salt in a solvent.

10. In paragraph 9, A method for producing a polymer solid electrolyte membrane, wherein 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. In paragraph 6, A method for manufacturing a polymer solid electrolyte membrane, wherein the above-mentioned cathode is a lithium cathode.

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

13. In paragraph 12, An all-solid-state battery, wherein the surface roughness of one side of the polymer solid electrolyte membrane is 1.00 ㎛ or less, and no additional film is formed between the other side of the polymer solid electrolyte membrane and the positive or negative electrode due to a side reaction.

14. In paragraph 12, An all-solid-state battery, wherein the above negative electrode is a lithium negative electrode.

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