Solid-liquid mixed electrolyte membrane and method for manufacturing the same

Abstract

The present disclosure relates to a method for manufacturing a solid-liquid mixed electrolyte membrane, comprising the following steps: (S1) preparing a dispersion comprising a plurality of solid polymer particles dispersed in a liquid electrolyte and a volatile organic solvent; (S2) applying the dispersion onto a substrate and then drying it to form a porous structure; and (S3) pressing the porous structure to obtain a solid-liquid mixed electrolyte membrane, wherein the solid polymer particles in the porous structure are stacked while being in contact with each other, and the porous structure comprises a pore structure formed between the solid polymer particles, the liquid electrolyte surrounds the inside of the pores of the porous structure, a portion where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles, the content of the liquid electrolyte is 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane, and the volatile organic solvent has a higher volatility compared to the liquid electrolyte.

Description

Technical Field

[0001] This application claims priority to Korean Patent Application No. 10-2020-0007480, filed in Korea on January 20, 2020. The present disclosure relates to a solid-liquid hybrid electrolyte membrane and a method of manufacturing the same. Background Art

[0002] As the use of transportation means, computers, and portable terminals has increased, the importance of lithium secondary batteries has also increased. In particular, there is a great need to develop lithium secondary batteries that are lightweight and provide high energy density. A lithium secondary battery can be obtained by interposing a separator between a positive electrode and a negative electrode and injecting a liquid electrolyte therein, or by interposing a solid electrolyte membrane between the positive electrode and the negative electrode.

[0003] However, in the case of a lithium ion battery using a liquid electrolyte, the negative electrode and the positive electrode are separated from each other by a separator. Therefore, when the separator is damaged by deformation or an external shock, a short circuit may occur, causing risks such as overheating or explosion.

[0004] In contrast, a lithium secondary battery (ALL SOLID STATE BATTERY) using a solid electrolyte has the advantage of enhanced safety and prevention of electrolyte leakage to improve battery reliability. However, even when using a solid electrolyte, there is still a need to develop a solid electrolyte membrane with high energy density and improved processability. In addition, in the case of a solid electrolyte, it has a problem of low ionic conductivity, resulting in reduced performance.

[0005] Furthermore, such a solid electrolyte membrane shows a significantly greater thickness compared to the thickness of a conventional porous polyolefin-based separator, resulting in a loss of energy density. In these cases, a technical solution capable of overcoming these problems is needed. Summary of the Invention

[0006] Technical Problem

[0007] The present disclosure is designed to solve the problems of the related art, and thus the present disclosure relates to providing a solid-liquid hybrid electrolyte membrane having a reduced thickness compared to commercially available solid electrolyte membranes while ensuring ionic conductivity.

[0008] The present disclosure also relates to providing a solid-liquid hybrid electrolyte membrane having improved mechanical strength even as a thinner membrane compared to commercially available solid electrolyte membranes.

[0009] In addition, the present disclosure relates to providing a solid-liquid hybrid electrolyte membrane having improved energy density per unit weight based on thickness even as a thinner membrane compared to commercially available solid electrolyte membranes.

[0010] Further, the present disclosure relates to a method for manufacturing a solid-liquid mixed electrolyte membrane that provides improved processability and an increased level of product finish.

[0011] These and other objects and advantages of the present disclosure will be understood from the following detailed description. In addition, it should be readily understood that the objects and advantages of the present disclosure can be achieved by the means shown in the appended claims and combinations thereof.

[0012] Technical Solution

[0013] In one aspect of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane according to any one of the following embodiments.

[0014] According to a first embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane, comprising the following steps: (S1) preparing a dispersion comprising a plurality of solid polymer particles dispersed in a liquid electrolyte and a volatile organic solvent;

[0015] (S2) applying the dispersion onto a substrate and then drying to form a porous structure; and (S3) pressing the porous structure to obtain a solid-liquid mixed electrolyte membrane,

[0016] wherein the solid polymer particles in the porous structure are stacked while being in contact with each other, and the porous structure comprises a pore structure formed between the solid polymer particles,

[0017] the liquid electrolyte surrounds the interior of the pores of the porous structure, the portions where the solid polymer particles are in surface contact with each other, or the surfaces of the solid polymer particles,

[0018] the content of the liquid electrolyte is 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane, and

[0019] the volatile organic solvent has a higher volatility than the liquid electrolyte.

[0020] According to a second embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in the first embodiment, wherein the volatile organic solvent has a boiling point of 30 °C to 200 °C.

[0021] According to a third embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in the first embodiment or the second embodiment, wherein the volatile organic solvent includes acrylonitrile, methyl ethyl ketone, acetone, tetrahydrofuran, pentane, hexane, benzene, chloroform, ether, dichloromethane, ethyl acetate, acetonitrile, methanol, methylene chloride, carbon disulfide, carbon tetrachloride, or a mixture of two or more of them.

[0022] According to a fourth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to third embodiments, wherein the solid polymer particles include engineering plastic resins.

[0023] According to a fifth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to fourth embodiments, wherein the engineering plastic resins include any one selected from polyphenylene sulfide, polyetheretherketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polypropylene, polyethylene, and poly(methyl methacrylate), or a mixture of two or more of them.

[0024] According to a sixth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to fifth embodiments, wherein the liquid electrolyte includes an organic solvent and a lithium salt, and the organic solvent is at least one of a linear carbonate, a linear ester, and a linear ether.

[0025] According to a seventh embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to sixth embodiments, wherein the weight ratio of the volatile organic solvent to the liquid electrolyte is from 83:17 to 66:34.

[0026] According to an eighth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to seventh embodiments, wherein the pressurization in step (S3) is a step of physically or chemically bonding the solid polymer particles to each other to obtain a porous structure having a pore structure formed between the solid polymer particles.

[0027] According to a ninth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to eighth embodiments, wherein the substrate includes a porous polymer substrate or a non-woven mesh substrate.

[0028] According to a tenth embodiment of the present disclosure, there is provided a method for manufacturing a solid-liquid mixed electrolyte membrane as defined in any one of the first to ninth embodiments, wherein the pores of the substrate are filled with the liquid electrolyte.

[0029] According to an eleventh embodiment of the present disclosure, there is provided a solid-liquid mixed electrolyte membrane including a plurality of solid polymer particles and a liquid electrolyte,

[0030] wherein the solid polymer particles are stacked while being in contact with each other and include a porous structure having a pore structure formed between the solid polymer particles,

[0031] the liquid electrolyte surrounds the inside of the pores of the porous structure, the portion where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles, and

[0032] the content of the liquid electrolyte is 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane.

[0033] According to a twelfth embodiment of the present disclosure, there is provided a solid-liquid mixed electrolyte membrane as defined in the eleventh embodiment, the solid-liquid mixed electrolyte membrane further including a porous polymer substrate or a non-woven mesh substrate.

[0034] According to a thirteenth embodiment of the present disclosure, there is provided a solid-liquid mixed electrolyte membrane as defined in the eleventh or twelfth embodiment, wherein the pores of the substrate are filled with the liquid electrolyte.

[0035] According to a fourteenth embodiment of the present disclosure, there is provided a lithium ion secondary battery including a positive electrode, a negative electrode, and a solid-liquid mixed electrolyte membrane interposed between the negative electrode and the positive electrode, wherein the solid-liquid mixed electrolyte membrane is the same as that defined in any one of the eleventh to thirteenth embodiments, and the negative electrode, the positive electrode, or both include a solid electrolyte material.

[0036] Advantageous Effects

[0037] According to an embodiment of the present disclosure, a deformable solid-liquid hybrid electrolyte membrane can be obtained by using solid polymer particles instead of inorganic particles.

[0038] In addition, since particulate polymers that can be compressed are used, a solid-liquid hybrid electrolyte membrane having improved mechanical strength can be provided. Also, since solid electrolytes are not used, a solid-liquid hybrid electrolyte membrane that can be deformed by external pressure can be provided. Further, the polymer particles are physically bonded to each other, which is advantageous for porosity and pore channel formation.

[0039] According to an embodiment of the present disclosure, since binder polymers are not used, a solid-liquid hybrid electrolyte membrane showing low resistance can be provided.

[0040] Meanwhile, according to an embodiment of the present disclosure, a small amount of liquid electrolyte is used to ensure improved ionic conductivity compared to conventional solid electrolyte batteries while preventing electrolyte leakage.

[0041] In addition, a solid-liquid hybrid electrolyte membrane having improved energy density per unit weight based on thickness can be provided.

[0042] Further, a method of manufacturing a solid-liquid hybrid electrolyte membrane that provides improved processability and an increased level of product completion can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the following disclosure, are used to provide a further understanding of the technical features of the present disclosure. Accordingly, the present disclosure should not be construed as being limited to the drawings. Also, the shapes, sizes, scales, or ratios of some of the components in the drawings may be exaggerated for purposes of clearer description.

[0044] Figure 1 is a schematic diagram illustrating a method of manufacturing a solid-liquid hybrid electrolyte membrane according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to the general meaning and dictionary meaning, but should be interpreted based on the meaning and concept corresponding to the technical aspects of the present disclosure on the basis of the principle that allows the inventor to appropriately define the terms for the best interpretation. Therefore, the description presented herein is only a preferred example for illustrative purposes and is not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalents and improvements can be made without departing from the scope of the present disclosure.

[0046] Throughout the specification, the expression "a part includes an element" does not exclude the existence of any other element, but means that the part may further include other elements, unless otherwise indicated.

[0047] As used herein, the terms "about", "substantially", or the like, when implying acceptable manufacturing and material tolerances unique to the claimed meaning, are used to mean from or contiguous to the claimed value and are used to prevent an inadvertent infringer from inappropriately using the claimed disclosure that includes the exact or absolute values provided to assist in understanding the present disclosure.

[0048] As used herein, the expression "A and / or B" means "A, B, or both of them".

[0049] The specific terms used in the following description are for illustrative purposes and are not restrictive. Terms such as "right", "left", "top surface", and "bottom surface" indicate directions in the drawings in which they are referred to. Terms such as "inward" and "outward" respectively indicate directions toward and away from the geometric center of the corresponding device, system, and its elements. "Front", "rear", "top", and "bottom" and related words and expressions indicate positions and points in the drawings in which they are referred to and should not be restrictive. These terms include the words listed above, their derivatives, and words having similar meanings.

[0050] The present disclosure relates to a solid-liquid mixed electrolyte membrane and a method for manufacturing the same.

[0051] In one aspect of the present disclosure, a solid-liquid mixed electrolyte membrane including a plurality of solid polymer particles and a small amount of liquid electrolyte is provided. Herein, the liquid electrolyte covers a portion where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles, and the amount of the liquid electrolyte used herein is small. Therefore, even when the solid-liquid mixed electrolyte membrane is pressurized during its manufacture, there is no leakage of the electrolyte, and the solid-liquid mixed electrolyte membrane provides an ionic conductivity equal to or similar to that of a conventional solid electrolyte membrane and exhibits a uniform ionic conductivity.

[0052] In the solid-liquid mixed electrolyte membrane, the solid polymer particles are stacked while being in contact with each other, and a small amount of liquid electrolyte is introduced into the pore channels formed by the solid polymer particles or the liquid electrolyte covers a portion where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles.

[0053] The solid-liquid mixed electrolyte membrane can be deformed by using polymer particles instead of inorganic particles, and can be deformed by external pressurization by using polymer particles instead of inorganic particles. In addition, the solid polymer particles are physically bonded to each other, which is advantageous for porosity and pore channel formation.

[0054] At the same time, since the solid-liquid mixed electrolyte membrane includes a small amount of liquid electrolyte, electrolyte leakage can be prevented while ensuring improved ionic conductivity compared to a conventional solid electrolyte membrane.

[0055] The solid-liquid mixed electrolyte membrane can be obtained by coating a porous structure formed by stacking solid polymer particles with a small amount of liquid electrolyte.

[0056] The present inventors have conducted in-depth research to obtain a solid-liquid mixed electrolyte membrane, particularly to develop a solid-liquid mixed electrolyte membrane having a high energy density per unit weight based on thickness.

[0057] The thin-film type solid-liquid mixed electrolyte membrane can be obtained by the following method: first, a thick film is formed by using a porous structure formed by solid polymer particles, and then pressurization is performed to obtain a thin film.

[0058] However, in order to obtain a thin-film type electrolyte membrane, even after the porous structure is formed, the porous structure should maintain its solid state, i.e., shape, while the dispersion applied to the substrate for forming the porous structure should maintain its fluidity during application.

[0059] To solve the above-mentioned problems, a solvent having a higher volatility than the liquid electrolyte is used according to the present disclosure, thereby providing a thin-film type solid-liquid mixed electrolyte membrane.

[0060] Figure 1FIG. is a schematic view illustrating a method of manufacturing a solid-liquid mixed electrolyte membrane according to an embodiment of the present disclosure. Hereinafter, the present disclosure will be explained in more detail with reference to the accompanying drawings.

[0061] Referring to Figure 1 (a), a dispersion 14 including a plurality of solid polymer particles 11 dispersed in a liquid electrolyte 12 and a volatile organic solvent 13 was prepared.

[0062] The solid polymer particles 11 exist in a solid state at room temperature and are polymer materials having low solubility in the electrolyte.

[0063] Meanwhile, according to the present disclosure, the solid polymer particles are surrounded by the liquid electrolyte and preferably have low solubility in the liquid electrolyte. In addition, the solid polymer particles are preferably polymers having excellent chemical resistance.

[0064] In particular, when impregnated with a liquid electrolyte or an organic solvent that can be used as a component of the liquid electrolyte, such as ethylene carbonate: ethyl methyl carbonate = 30:70 (vol%), the solid polymer particles have a solubility of less than 30 wt% at 20°C to 30°C. More particularly, the solid polymer particles may have a solubility of less than 20%, less than 15%, or less than 10%. Therefore, even when the solid polymer particles are dispersed in the solvent, they can exist in a solid state.

[0065] In particular, the solid polymer particles may be engineering plastic resins.

[0066] Herein, the engineering plastic resins may include any one selected from polyphenylene sulfide (PPS), polyetheretherketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polypropylene, polyethylene, and poly(methyl methacrylate)), or a mixture of two or more of them.

[0067] In the present disclosure, the engineering plastic resin may have a molecular weight of 100,000 - 10,000,000 Da.

[0068] Unlike the inorganic particles available in the conventional market, the solid polymer particles have compressibility. Therefore, a lithium secondary battery having an increased energy density per unit weight based on thickness can be provided. In addition, a deformable solid-liquid mixed electrolyte membrane can be provided by using solid polymer particles instead of a conventional solid electrolyte. The solid polymer particles have ductility and can thus physically or chemically adhere, bond, or interconnect under pressure or heating. As a result, the solid-liquid mixed electrolyte membrane according to the present disclosure does not require a separate binder polymer. That is, the solid-liquid mixed electrolyte membrane is free of a binder polymer. Therefore, a solid-liquid mixed electrolyte membrane showing a reduced resistance can be provided.

[0069] For example, the solid polymer particles may have an average particle diameter of 100 nm to 20 μm, 100 nm to 10 μm, 200 nm to 5 μm, or 500 nm to 2 μm. When the solid polymer particles have a particle diameter controlled within the above-defined range, an appropriate pore size can be obtained, short circuits can be prevented, and sufficient impregnation with a liquid electrolyte can be allowed.

[0070] The liquid electrolyte is present in the portion where the solid polymer particles are in surface contact with each other, or around the surface of the solid polymer particles, that is, all or at least a part of the surface of the solid polymer particles can be coated with the liquid electrolyte.

[0071] Due to the presence of the liquid electrolyte as described above, a solid-liquid mixed electrolyte membrane having a high ionic conductivity can be provided.

[0072] According to an embodiment of the present disclosure, the liquid electrolyte cannot dissolve the solid polymer particles and has excellent chemical resistance and electrochemical resistance.

[0073] For example, the electrolyte is a salt having an A + B - structure, where A + includes alkali metal cations such as Li + , Na + , K + , or a combination thereof, and B - includes such as PF 6 - , BF 4 - , Cl - , Br - , I - , ClO 4 - , AsF 6- , CH 3 CO 2 - , CF 3 SO 3 - , N(CF 3 SO 2 ) 2 - , C(CF 2 SO 2 ) 3 - anions such as these, or combinations thereof, where the salt is soluble or dissociable in organic solvents such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma-butyrolactone (γ-butyrolactone), or mixtures thereof, but not limited thereto.

[0074] According to the present disclosure, the volatile organic solvent has a higher volatility compared to the liquid electrolyte. That is, the volatile organic solvent is a factor that rapidly evaporates after the dispersion is coated on a substrate as described below, while ensuring the fluidity of the dispersion, and thus aids in forming a porous structure.

[0075] Therefore, the volatile organic solvent may have a boiling point of 30°C to 200°C, 40°C to 150°C, or 50°C to 100°C.

[0076] In addition, the volatile organic solvent may have a boiling point that is 5°C to 100°C, 10°C to 90°C, or 30°C to 80°C lower than the boiling point of the liquid electrolyte used in the dispersion.

[0077] In addition, the volatile organic solvent may have a vapor pressure that is 10% to 10000%, 20% to 1000%, or 50% to 500% higher than the vapor pressure of the liquid electrolyte.

[0078] In addition, the volatile organic solvent cannot dissolve the solid polymer particles and has excellent chemical and electrochemical resistance.

[0079] According to an embodiment of the present disclosure, the volatile organic solvent may include acrylonitrile, methyl ethyl ketone, acetone, tetrahydrofuran, pentane, hexane, benzene, chloroform, ether, dichloromethane, ethyl acetate, acetonitrile, methanol, methylene chloride, carbon disulfide, carbon tetrachloride, or mixtures of two or more of them.

[0080] In this text, the weight ratio of the liquid electrolyte to the volatile organic solvent can be from 83:17 to 66:34, from 50:50 to 34:66, or from 17:83 to 9:91. When the weight ratio of the liquid electrolyte to the volatile organic solvent falls within the range defined above, post-treatments such as roll pressing can be advantageously carried out after applying the dispersion to the substrate, and the resulting solid-liquid mixed electrolyte film shows a qualified level of ionic conductivity.

[0081] Next, as Figure 1 (b) shows, the dispersion 14 is applied to the substrate 15 and then dried to form a porous structure (S2).

[0082] In this text, the method of applying the dispersion to the substrate can be any method conventionally used in the art. For example, the method can include dip coating, spraying, or drop coating.

[0083] In addition, the method of drying the dispersion can be any method conventionally used in the art without particular limitation.

[0084] However, preferably, the liquid electrolyte in the dispersion does not evaporate but remains therein while the volatile organic solvent evaporates.

[0085] Accordingly, the drying temperature can vary with the specific types of the liquid electrolyte and the volatile organic solvent. In particular, the dispersion can be dried in a temperature range where the liquid electrolyte does not evaporate while the volatile organic solvent evaporates.

[0086] In this text, the substrate can be any one selected from a release film, a porous polymer substrate, and an electrode. When the substrate is a release film, the release film is removed from the finished solid-liquid mixed electrolyte film. The release film only serves as a mold in the manufacture of the solid-liquid mixed electrolyte film. Therefore, when the release film is applied to an electrochemical device such as a secondary battery, it is removed from the solid-liquid mixed electrolyte film and is not included as a structural element of the electrochemical device. In this way, by applying and drying the dispersion, a porous structure can be formed, which includes solid polymer particles stacked therein and a liquid electrolyte introduced into the spaces where the solid polymer particles are in surface contact with each other.

[0087] Then, as Figure 1 (c) shows, the porous structure is pressed to form a solid-liquid mixed electrolyte film.

[0088] In this text, the solid polymer particles and the liquid electrolyte in the porous structure are rearranged by pressing to provide a thin-film type electrolyte film with a reduced thickness.

[0089] Meanwhile, the solid polymer particles are physically bonded to each other by pressure to provide a mixed electrolyte membrane with increased bonding strength. Meanwhile, in the present disclosure, the solid polymer particles are ductile and do not require a separate binder polymer. In this way, a solid-liquid mixed electrolyte membrane showing reduced resistance can be obtained. Figure 1 (d).

[0090] Meanwhile, according to an embodiment of the present disclosure, the liquid electrolyte is present in a small amount after drying the dispersion. Therefore, a solid-liquid mixed electrolyte membrane having improved ionic conductivity compared to a conventional solid electrolyte membrane can be provided. For example, the content of the liquid electrolyte can be 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane. More particularly, the content of the liquid electrolyte can be 1 wt% or more, 2 wt% or more, 3 wt% or more, 4 wt% or more, or 5 wt% or more, and 20 wt% or less, 19 wt% or less, 18 wt% or less, 17 wt% or less, or 16 wt% or less based on the total weight of the solid-liquid mixed electrolyte membrane. Meanwhile, according to an embodiment of the present disclosure, a solid-liquid mixed electrolyte membrane having high ionic conductivity even when the liquid electrolyte is present in a small amount can be provided. This is because the liquid electrolyte is uniformly dispersed on the surface of the solid polymer particles or on the part where the solid polymer particles are in surface contact with each other.

[0091] As described above, when such a small amount of liquid electrolyte is incorporated into the solid-liquid mixed electrolyte membrane, the solid-liquid mixed electrolyte membrane can have a porosity of 0 vol% to 49 vol%, 1 vol% to 40 vol%, 2 vol% to 20 vol%, or 5 vol% to 10 vol% based on the total volume of the solid polymer particles.

[0092] As used herein, the term "pore" can have various types of pore structures, and any type of pore having an average pore size that satisfies the above-defined average pore size as measured by a porosimeter or as observed by field emission scanning electron microscopy (FE-SEM) falls within the scope of the present disclosure.

[0093] As described above, since the solid-liquid mixed electrolyte membrane is uniformly impregnated with a small amount of liquid electrolyte, a solid-liquid mixed electrolyte membrane having a high ionic conductivity of 10 -4 S / cm to 5x10 -3 S / cm can be provided.

[0094] According to an embodiment of the present disclosure, the solid-liquid hybrid electrolyte membrane may further include a porous polymer substrate or a non-woven mesh substrate. In particular, the solid-liquid hybrid electrolyte membrane according to an embodiment of the present disclosure has a large amount of liquid electrolyte, and is impregnated with the liquid electrolyte. Therefore, when the solid-liquid hybrid electrolyte membrane is formed on the porous polymer substrate or the non-woven mesh substrate, or when a separate porous polymer substrate or non-woven mesh substrate is inserted, there is an advantage of high mechanical strength. At the same time, according to an embodiment of the present disclosure, when the solid-liquid hybrid electrolyte membrane further includes a porous polymer substrate or a non-woven mesh substrate, the porous polymer substrate or the non-woven mesh substrate is preferably impregnated with the liquid electrolyte so that the internal pores can be filled with the liquid electrolyte.

[0095] In particular, the non-woven mesh substrate may include polyolefins such as polyethylene or polypropylene, polyethylene terephthalate, polyester, polyamide, polyacetal, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene ether, polyphenylene sulfide, polyethylene naphthalate, or a mixture thereof.

[0096] At the same time, the solid polymer particles may be partially embedded in the pores of the non-woven mesh substrate. Herein, the surface of the solid polymer particles and the substrate may be surrounded by the liquid electrolyte.

[0097] At the same time, the solid polymer particles may be disposed on at least one surface of the non-woven mesh substrate. Herein, the surface of the solid polymer particles and the substrate may be surrounded by the liquid electrolyte.

[0098] According to an embodiment of the present disclosure, the solid-liquid hybrid electrolyte membrane is a thin film that may have a thickness of 10 μm to 500 μm, 20 μm to 300 μm, or 40 μm to 100 μm. When a secondary battery is subsequently manufactured, such a thin film separator according to an embodiment of the present disclosure can be provided, which is advantageous in terms of energy density.

[0099] Hereinafter, a secondary battery including the solid-liquid hybrid electrolyte membrane according to the present disclosure will be explained. The secondary battery includes a negative electrode, a positive electrode, and a solid-liquid hybrid electrolyte membrane interposed between the negative electrode and the positive electrode. Herein, the term "secondary battery" refers to a system that converts external electrical energy into chemical energy, stores chemical energy, and then generates electricity when necessary. Generally, secondary batteries include lead storage batteries, nickel-cadmium batteries (NiCd), nickel-metal hydride storage batteries (NiMH), lithium-ion batteries, or the like. According to an embodiment of the present disclosure, the secondary battery may be a lithium-ion secondary battery.

[0100] The positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on at least one surface of the positive electrode current collector, wherein the positive electrode active material layer includes a positive electrode active material and a conductive material, and may include at least one of an adhesive resin and a solid electrolyte material. In addition, the positive electrode active material layer may further include various additives to supplement or improve the electrochemical properties.

[0101] The positive electrode active material layer may have pores formed by vacant spaces between the positive electrode active materials or the like, and thus may have a porous structure. The positive electrode active material layer may have a porosity of about 12 vol% to about 35 vol%.

[0102] The positive electrode active material is not particularly limited as long as it can be used as the positive electrode active material of a lithium ion secondary battery. Non-limiting examples of the positive electrode active material may include any one selected from the following: layered compounds such as lithium manganese composite oxides (LiMn 2 O 4 , LiMnO 2 , etc.), lithium cobalt oxide (LiCoO 2 ), and lithium nickel oxide (LiNiO 2 ), or those compounds substituted with one or more transition metals; such as those represented by the chemical formula Li 1+x Mn 2-x O 4 (where x is 0 - 0.33), LiMnO 3 , LiMn 2 O 3 , and LiMnO 2 and the like of lithium manganese oxides; lithium copper oxide (Li 2 CuO 2 ); such as LiV 3 O 8 , LiV 3 O 4 , V 2 O 5 , and Cu 2 V 2 O 7 and the like of lithium vanadium oxides; Ni-site type lithium nickel oxides represented by the chemical formula LiNi 1-x M x O 2 (where M is Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x is 0.01 - 0.3); Ni-site type lithium nickel oxides represented by the chemical formula LiMn 2-x M x O 2 (where M is Co, Ni, Fe, Cr, Zn, or Ta), and x is 0.01 - 0.1) or Li 2 Mn3 MO 8 (where M is Fe, Co, Ni, Cu, or Zn) lithium manganese composite oxide; in which Li is partially replaced by alkaline earth metal ions in LiMn 2 O 4 ; a disulfide compound; and Fe 2 (MoO 4 ) 3 , or a mixture of two or more of them.

[0103] Meanwhile, the negative electrode includes a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector, where the negative electrode active material layer includes a negative electrode active material and a conductive material, and may include at least one of an adhesive resin and a solid electrolyte material. In addition, the negative electrode active material layer may further include various additives to supplement or improve the electrochemical properties.

[0104] The negative electrode active material layer may have pores formed by vacant spaces between the negative electrode active materials, or the like, and thus may have a porous structure. The negative electrode active material layer may have a porosity of about 15 vol% to about 40 vol%.

[0105] The negative electrode active material can be any negative electrode active material as long as it can be used as the negative electrode active material of a lithium ion secondary battery. Specific examples of the negative electrode active material include any one selected from the following: carbon such as non-graphitized carbon and graphite-based carbon; such as Li x Fe 2 O 3 (0 ≤ x ≤ 1), Li x WO 2 (0 ≤ x ≤ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, elements of Group 1, Group 2 or Group 3 in the periodic table, halogen; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8) metal composite oxides; lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; such as SnO, SnO 2 , PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi2 O 3 , Bi 2 O 4 , Bi 2 O 5 , or metal oxides such as the like; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; titanium oxides; and lithium titanium oxides, or two or more of them. According to a specific embodiment, the negative electrode active material may include a carbonaceous material and / or Si.

[0106] Meanwhile, according to the present disclosure, each of the positive electrode current collector and the negative electrode current collector includes a conductive metal plate, and may be one appropriately selected depending on the polarity of the electrodes known in the field of secondary batteries.

[0107] According to the present disclosure, the conductive material is generally added in an amount of 1 wt% to 30 wt% based on the total weight of the mixture including the electrode active material. There is no particular limitation on the conductive material as long as it does not cause a chemical change in the corresponding battery and has conductivity. For example, the conductive material includes any one selected from the following: graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal carbon black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride, aluminum, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxides; and conductive materials such as polyphenylene derivatives, or a mixture of two or more of them.

[0108] According to the present disclosure, there is no particular limitation on the binder resin as long as it is a component that assists in bonding the electrode active material and the conductive material and bonds to the current collector. Specific examples of the binder resin include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, various copolymers, or the like. Generally, the binder resin can be used in an amount of 1 wt% to 30 wt%, or 1 wt% to 10 wt% based on 100 wt% of the electrode active material layer.

[0109] Meanwhile, according to the present disclosure, if necessary, each electrode active material layer may include at least one additive such as an oxidation stabilizing additive, a reduction stabilizing additive, a flame retardant, a heat stabilizer, an antifogging agent, or the like.

[0110] Preferably, the solid electrolyte material can be a solid electrolyte with high reduction stability. Since the solid electrolyte material is mainly used to conduct lithium ions, any material with a high ionic conductivity such as 10 -5 S / cm or greater, or 10 -5 S / cm or greater can be used, and the solid electrolyte material is not limited to any specific composition.

[0111] The solid electrolyte material can include at least one of a sulfide-based solid electrolyte material, an oxide-based solid electrolyte material, and a polymer solid electrolyte material.

[0112] The polymer solid electrolyte material can be a polymer solid electrolyte formed by adding a polymer resin to a solvated electrolyte salt, or a polymer gel electrolyte including a polymer resin impregnated with an organic electrolyte containing an organic solvent and an electrolyte salt, an ionic liquid, a monomer, or an oligomer, or the like.

[0113] According to an embodiment of the present disclosure, specific examples of the polymer solid electrolyte may include a polyether polymer, a polycarbonate polymer, an acrylate polymer, a polysiloxane polymer, a phosphazene polymer, a polyether derivative, an alkylene oxide derivative, a polyphosphate polymer, a poly agitation lysine, a polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer containing an ionizable dissociable group, or the like.

[0114] The polymer solid electrolyte may include a branched copolymer, a comb-like polymer, and a crosslinked polymer resin, including a poly(ethylene oxide) (PEO) backbone copolymerized with a comonomer containing at least one amorphous polymer selected from PMMA, polycarbonate, polysiloxane (pdms), and phosphazene, or a mixture thereof.

[0115] In addition, the polymer gel electrolyte includes an organic electrolyte containing an electrolyte salt and a polymer resin, wherein the organic electrolyte is used in an amount of 60 parts by weight to 400 parts by weight based on the weight of the polymer resin. The polymer used for the gel electrolyte is not particularly limited, but specific examples thereof include a polyether polymer, a PVC polymer, a PMMA polymer, polyacrylonitrile (PAN), polyvinylidene fluoride (PVdF), poly(vinylidene fluoride - hexafluoro propylene) (PVdF - HFP), or the like. Mixtures of these polymers can also be used.

[0116] In addition, the electrolyte salt can be composed of Li+ X - The ionizable lithium salt represented. Preferably, such a lithium salt may be selected from the group consisting of LiTFSI, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , LiSCN, LiCF 3 CO 2 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiC 4 F 9 SO 3 , LiC(CF 3 SO 2 ) 3 , (CF 3 SO 2 ) 2 NLi, lithium chloroborate, lithium lower aliphatic carboxylate, lithium 4-phenylborate imide, and combinations thereof. More preferably, the lithium salt may be LiTFSI (lithium bistrifluoromethanesulfonimide).

[0117] According to the present disclosure, the sulfide-based solid electrolyte material includes sulfur (S), has a conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table, and may include a Li-P-S-based glass or a Li-P-S-based glass ceramic. Non-limiting examples of the sulfide-based solid electrolyte include Li 2 S-P 2 S 5 , Li 2 S-LiI-P 2 S 5 , Li 2 S-LiI-Li 2 O-P 2 S 5 , Li 2 S-LiBr-P 2S 5 、Li 2 S-Li 2 O-P 2 S 5 、Li 2 S-Li 3 PO 4 -P 2 S 5 、Li 2 S-P 2 S 5 -P 2 O 5 、Li 2 S-P 2 S 5 -SiS 2 、Li 2 S-P 2 S 5 -SnS、Li 2 S-P 2 S 5 -Al 2 S 3 、Li 2 S-GeS 2 、Li 2 S-GeS 2 -ZnS、 or at least one of the like. However, the scope of the present disclosure is not limited thereto.

[0118] In addition, the oxide-based solid electrolyte material includes oxygen (O) and has conductivity of metal ions belonging to Group 1 or Group 2 of the periodic table. Non-limiting examples of the oxide-based solid electrolyte include LLTO-based compounds, Li 6 La 2 CaTa 2 O 12 、Li 6 La 2 ANb 2 O 12 (where A is Ca or Sr), Li 2 Nd 3 TeSbO 12 、Li 3 BO 2.5 N 0.5 、Li 9 SiAlO 8 、 LAGP-based compounds, LATP-based compounds, Li 1+x Ti 2-x Al x Si y (PO 4 ) 3-y(where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1), LiAl x Zr 2-y (PO 4 ) 3 (where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1), LiTi x Zr 2-y (PO 4 ) 3 (where 0 ≤ x ≤ 1, 0 ≤ y ≤ 1), at least one of a LISICON-based compound, a LIPON-based compound, a perovskite-based compound, a NASICON-based compound, and a LLZO-based compound. However, the scope of the present disclosure is not limited thereto.

[0119] Meanwhile, a secondary battery according to the present disclosure can be obtained by forming an electrode assembly including one or more negative electrodes, a solid-liquid mixed electrolyte membrane, and a positive electrode stacked in sequence and introducing the electrode assembly into a battery case. The electrode assembly can be provided in either a bi-cell type in which the outermost electrodes have different polarities or a mono-cell type in which the outermost electrodes have the same polarity. In addition, the electrode assembly can be prepared in a jelly roll type, a stacked type, or a stacked / folded type depending on desired battery characteristics.

[0120] According to an embodiment of the present disclosure, a lithium ion battery can be provided in the form of a solid state battery without additionally injecting a liquid electrolyte into the battery case except for the electrode assembly. Otherwise, a liquid electrolyte can be additionally injected in addition to the liquid electrolyte included in the solid-liquid mixed electrolyte membrane. Herein, when referring to the additionally injected liquid electrolyte, reference will be made to the solid-liquid mixed electrolyte membrane.

[0121] Now, examples and test examples will be described. The following examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure.

[0122] Example 1

[0123] First, a dispersion including powdered polyphenylene sulfide (average particle diameter: 10 μm) as solid polymer particles dispersed in a liquid electrolyte (ethylene carbonate: ethyl methyl carbonate = 3:7 (vol%), LiPF 6 1M, vinylene carbonate 0.5 wt%, fluoroethylene carbonate 1 wt%) and acetonitrile as a volatile organic solvent in a weight ratio of 20:40:40 was prepared.

[0124] Next, a separator (polyethylene, thickness 9 μm) was placed on the peeled poly(ethylene terephthalate) (PET) film, and 3 mL of the dispersion was applied to the separator. The resulting structure was dried overnight to obtain a solid-liquid mixed electrolyte film with a thickness of 53 μm. Then, roll pressing was performed to increase the contact force between the particles and / or between the particles and the separator and to reduce the thickness, thereby providing a solid-liquid mixed electrolyte film with a thickness of 33 μm. After that, the peeled poly(ethylene terephthalate) film was removed.

[0125] Example 2

[0126] A solid-liquid mixed electrolyte film was obtained in the same manner as in Example 1, except that the dispersion had a composition weight ratio of 20:20:60, the solid-liquid mixed electrolyte film had a thickness of 48 μm after drying and a thickness of 26 μm after roll pressing.

[0127] Example 3

[0128] A solid-liquid mixed electrolyte film was obtained in the same manner as in Example 2, except that methyl ethyl ketone was used as the volatile organic solvent instead of acetonitrile, the dispersion had a composition weight ratio of 20:20:60, the solid-liquid mixed electrolyte film had a thickness of 50 μm after drying and a thickness of 28 μm after roll pressing.

[0129] Example 4

[0130] A solid-liquid mixed electrolyte film was obtained in the same manner as in Example 2, except that no separator was used during coating with the dispersion and the dispersion was directly coated on the PET release film, the solid-liquid mixed electrolyte film had a thickness of 235 μm after drying and a thickness of 155 μm after roll pressing.

[0131] Comparative Example 1

[0132] An electrolyte film was obtained in the same manner as in Example 1, except that no volatile organic solvent was introduced during the preparation of the dispersion and the weight ratio of the solid polymer particles to the liquid electrolyte was 20:80. The resulting product had a thickness of 51 μm after drying, but an electrolyte film could not be obtained during roll pressing due to the too low adhesion between the solid polymer particles.

[0133] Comparative Example 2

[0134] An electrolyte film was obtained in the same manner as in Example 1, except that no volatile organic solvent was introduced during the preparation of the dispersion and the weight ratio of the solid polymer particles to the liquid electrolyte was 50:50. However, the dispersion did not have fluidity and thus could not be coated on the separator.

[0135] Comparative Example 3

[0136] An electrolyte membrane was obtained in the same manner as in Example 2, except that dimethylformamide was used as the non-volatile organic solvent instead of acetonitrile as the volatile organic solvent. An electrolyte membrane having a thickness of 47 μm after drying and a thickness of 28 μm after roll pressing was obtained. Here, for the purpose of removing dimethylformamide, the drying conditions were vacuum drying at 100 °C for 24 hours.

[0137] Comparative Example 4

[0138] No separator was used, and the dispersion according to Comparative Example 1 was directly coated on the release film. The resulting product had a thickness of 244 μm after drying, but an electrolyte membrane could not be obtained during roll pressing due to too low adhesion between the particles.

[0139] Comparative Example 5

[0140] Polyethylene oxide (PEO, Mw = 4,000,000 g / mol) was dissolved in acetonitrile (AN) as a volatile organic solvent to prepare a polymer solution with a concentration of 4 wt%. Here, LiTFSI as a lithium salt was added thereto to a molar ratio of [EO] / [Li + of 18 / 1. The resulting mixture was stirred overnight at 70 °C so that PEO and the lithium salt could be sufficiently dissolved in the polymer solution. Next, an additive solution including an initiator and a curing agent was prepared. The curing agent was polyethylene glycol diacrylate (PEGDA, Mw = 575), and the initiator was benzoyl peroxide (BPO). PEGDA was used in an amount of 20 wt% based on PEO, and BPO was used in an amount of 1 wt% based on PEGDA. Acetonitrile was used as the solvent. The additive solution was stirred for about 1 hour so that the components introduced therein could be thoroughly mixed. Then, the additive solution was added to the polymer solution, and the two solutions were thoroughly mixed. The mixed solution was applied and coated on the release film using a doctor blade. The coating gap was set to 300 μm, and the coating rate was set to 20 mm / min. The release film coated with the solution was transferred to a glass plate, kept flat, dried overnight at room temperature, and vacuum dried at 100 °C for 12 hours. In this way, a solid electrolyte membrane was obtained. The resulting solid electrolyte membrane had a thickness of about 50 μm.

[0141] Measurement of the ionic conductivity of the solid-liquid mixed electrolyte membrane

[0142] Each solid-liquid mixed electrolyte membrane according to the examples and comparative examples was cut into a circle with a size of 1.7671 cm 2 and the electrolyte membrane was inserted between two stainless steel sheets to obtain a coin cell. Then, the electrochemical impedance was measured at room temperature using an analyzer (VMP3, Biologic science instrument) under the conditions of an amplitude of 10 mV and a scanning range of 500 kHz to 0.1 MHz. Based on this, the ionic conductivity was calculated.

[0143] In this article, the ionic conductivity of each of Examples 1 to 4 and Comparative Examples 1 to 4 was measured at room temperature, and the ionic conductivity of Comparative Example 5 was measured at 60 °C.

[0144] [Table 1]

[0145]

[0146] As can be seen from [Table 1], according to the embodiments of the present disclosure, a self-standing film can be obtained by using a dispersion to which a volatile solvent is added. The dispersion has a reduced concentration for coating and an appropriate volatile solvent is added to increase the final solid content after coating and ensure strength, while fully controlling the ratio of the solid phase to the liquid phase, and thus a self-standing film can be obtained. Compared with the conventional solid electrolyte (Comparative Example 5) exemplified by polyethylene oxide, the solid-liquid mixed electrolyte membrane according to the embodiments of the present disclosure shows excellent properties such as physical properties and ionic conductivity. In particular, a solid-liquid mixed electrolyte membrane with excellent ionic conductivity can be obtained by the dispersion coating process through the combination of a structure including particles and an electrolyte. In addition, when a separator is introduced, a thin film type electrolyte membrane with a thickness less than 50 μm can be obtained.

[0147] [Reference Signs]

[0148] 100: Solid-liquid mixed electrolyte membrane

[0149] 11: Solid polymer particles

[0150] 12: Liquid electrolyte

[0151] 13: Volatile organic solvent

[0152] 14: Dispersion

[0153] 15: Substrate

Claims

1. A method for manufacturing a solid-liquid mixed electrolyte membrane, comprising the following steps: (S1) Prepare a dispersion comprising a plurality of solid polymer particles dispersed in a liquid electrolyte and a volatile organic solvent; (S2) Apply the dispersion onto a substrate and then dry it to form a porous structure; and (S3) Pressurize the porous structure to obtain a solid-liquid mixed electrolyte membrane, wherein the solid polymer particles in the porous structure are stacked while being in contact with each other, and the porous structure comprises a pore structure formed between the solid polymer particles, the liquid electrolyte surrounds the interior of the pores of the porous structure, the portion where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles, the content of the liquid electrolyte is 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane, the weight ratio of the volatile organic solvent to the liquid electrolyte is 83:17 to 66:34, and the volatile organic solvent has a higher volatility compared to the liquid electrolyte.

2. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the volatile organic solvent has a boiling point of 30°C to 200°C.

3. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the volatile organic solvent comprises acrylonitrile, methyl ethyl ketone, acetone, tetrahydrofuran, pentane, hexane, benzene, chloroform, ether, dichloromethane, ethyl acetate, acetonitrile, methanol, methylene chloride, carbon disulfide, carbon tetrachloride, or a mixture of two or more of them.

4. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the solid polymer particles comprise an engineering plastic resin.

5. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the solid polymer particles comprise an engineering plastic resin, and the engineering plastic resin comprises any one selected from polyphenylene sulfide, polyether ether ketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polypropylene, polyethylene, and polymethyl methacrylate, or a mixture of two or more of them.

6. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the liquid electrolyte comprises an organic solvent and a lithium salt, and the organic solvent is at least one of a linear carbonate, a linear ester, and a linear ether.

7. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the pressurization in step (S3) is a step of physically or chemically bonding the solid polymer particles to each other to obtain a porous structure having a pore structure formed between the solid polymer particles.

8. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 1, wherein the substrate comprises a porous polymer substrate or a non-woven mesh substrate.

9. The method for manufacturing a solid-liquid mixed electrolyte membrane according to claim 8, wherein the interior of the pores of the substrate is filled with the liquid electrolyte.

10. A solid-liquid mixed electrolyte membrane obtained by the method defined in any one of claims 1 to 9, the solid-liquid mixed electrolyte membrane comprising a plurality of solid polymer particles and a liquid electrolyte, wherein the solid polymer particles are stacked while being in contact with each other and comprise a porous structure having a pore structure formed between the solid polymer particles, the liquid electrolyte surrounds the interior of the pores of the porous structure, the portions where the solid polymer particles are in surface contact with each other, or the surface of the solid polymer particles, and the content of the liquid electrolyte is 1 wt% to 20 wt% based on the total weight of the solid-liquid mixed electrolyte membrane.

11. The solid-liquid mixed electrolyte membrane according to claim 10, the solid-liquid mixed electrolyte membrane further comprising a porous polymer substrate or a non-woven mesh substrate.

12. The solid-liquid mixed electrolyte membrane according to claim 10, wherein the interior of the pores of the substrate is filled with the liquid electrolyte.

13. A lithium ion secondary battery comprising a positive electrode, a negative electrode, and a solid-liquid mixed electrolyte membrane interposed between the negative electrode and the positive electrode, wherein the solid-liquid mixed electrolyte membrane is the same as that defined in claim 10, and the negative electrode, the positive electrode, or both comprise a solid electrolyte material.

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