Polymer solid electrolyte laminate and method for manufacturing the same

Abstract

The present invention relates to a polymer solid electrolyte laminate and a manufacturing method thereof. More specifically, the polymer solid electrolyte laminate includes a protective layer formed on at least one surface of a polymer solid electrolyte, and the protective layer can protect the polymer solid electrolyte from being affected by moisture and the outside air during all subsequent processes, such as post-processing and transportation of the polymer solid electrolyte, during a continuous process for mass production of the polymer solid electrolyte.

Description

[Technical Field]

[0001] This application claims priority rights under Korean Patent Application No. 10-2022-0067054 dated May 31, 2022, and Korean Patent Application No. 10-2023-0070061 dated May 31, 2023, and incorporates all the contents disclosed in the documents of said Korean patent applications as part of this specification.

[0002] The present invention relates to a polymer solid electrolyte laminate and a method for producing the same. [Background technology]

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

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

[0005] Among solid electrolytes, polymer solid electrolytes may use ion-conducting polymer materials as raw materials, and hybrid materials in which polymer materials and inorganic materials are mixed have also been proposed. As the inorganic material, inorganic materials such as oxides or sulfides may be used.

[0006] Conventional polymer solid electrolytes were manufactured through a process of forming a coating film followed by high-temperature drying. However, conventional polymer solid electrolyte manufacturing techniques had limitations in producing polymer solid electrolytes with improved ionic conductivity due to the high crystallinity of crystalline or semi-crystalline polymers. In other words, the higher the degree of crystallinity of the polymer, the lower the chain mobility of the polymer chains, 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.

[0007] For example, conventional polymer solid electrolytes can be manufactured by using polyvinyl alcohol (PVA), which contains hydroxyl groups as crosslinking functional groups, as the polymer, forming a coating film, and then going through a high-temperature drying process. Specifically, the PVA can be dissolved in water to produce an aqueous PVA solution, which is then applied to a substrate by solution casting to form a coating film, and dried at room temperature or high temperature to produce a PVA film-like polymer solid electrolyte. In this case, high temperature may mean 80°C or higher, which is the glass transition temperature (Tg) of PVA. In the drying process, after the water evaporates, hydrogen bonds are formed between the crosslinking functional groups contained in the PVA, and these hydrogen bonds cause chain folding of the polymer chains, resulting in a phenomenon in which the crystallinity of the polymer film increases. The higher the crystallinity, the more brittle the polymer film is formed. In polymer films with high crystallinity and brittleness, the chain mobility of the polymer chains decreases, and if dissociated ions are present inside the polymer film, the ion mobility also decreases significantly. Therefore, as mentioned above, general PVA films manufactured by a process of forming a coating film and then drying it at high temperature will exhibit physical properties that make them unsuitable as polymer solid electrolytes for lithium secondary batteries.

[0008] To overcome such limitations of conventional polymer solid electrolytes, a technique has been developed in which a plasticizer is added to a crystalline polymer or semi-crystalline polymer to improve the mobility of polymer chains and enhance the ionic conductivity of the polymer solid electrolyte. However, when using a plasticizer, it is sometimes difficult to set process conditions because appropriate dispersion and solubility (miscibility) between the polymer and the plasticizer must be ensured. Also, when applying a liquid plasticizer, the compatibility with the polymer may decrease, making it difficult to carry out the manufacturing process of the polymer solid electrolyte.

[0009] Therefore, there is a need for the development of a technique that can improve the ionic conductivity of polymer solid electrolytes without using a separate additive such as a plasticizer.

[0010] In addition, there is also an increasing demand for the development of a technique that can prevent the physical properties of the polymer solid electrolyte from changing due to moisture and outside air during all the processes for manufacturing the polymer solid electrolyte.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] An object of the present invention is to provide a polymer solid electrolyte laminate that can prevent the physical properties of the polymer solid electrolyte from changing due to moisture and outside air during the manufacturing process of the polymer solid electrolyte.

[0013] Another object of the present invention is to provide a method for manufacturing the polymer solid electrolyte laminate.

Means for Solving the Problems

[0014] To achieve the above object, the present invention provides a polymer solid electrolyte laminate including a polymer containing a crosslinkable functional group, a lithium salt, and a solvent; and a protective layer formed on at least one surface of the polymer solid electrolyte. The polymer solid electrolyte includes a crosslinked structure and an amorphous polymer chain containing the crosslinkable functional group. The crosslinked structure includes (a) crosslinking between crosslinkable functional groups, (b) crosslinking between a crosslinkable functional group and a solvent, and (c) bonding between a crosslinkable functional group and a lithium salt.

[0015] The present invention also provides a method for manufacturing the polymer solid electrolyte laminate, including: (S1) adding a lithium salt to a polymer solution containing a crosslinkable functional group to form a solution for forming a polymer solid electrolyte; (S2) coating the solution for forming a polymer solid electrolyte on a substrate to form a coating film; (S3) freezing and thawing the coating film to form a polymer solid electrolyte; and (S4) laminating a protective layer on at least one surface of the polymer solid electrolyte.

Advantages of the Invention

[0016] The polymer solid electrolyte laminate according to the present invention includes a protective layer formed on at least one surface of the polymer solid electrolyte. After the production of the polymer solid electrolyte, the protective layer can prevent the physical properties of the polymer solid electrolyte from changing due to moisture and external air in subsequent processes such as the lamination process with electrodes and transportation.

Embodiments for Carrying out the Invention

[0017] Hereinafter, the present invention will be described in more detail to facilitate understanding of the present invention.

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

[0019] As used herein, the term "crosslinked structure" refers to a structure that includes a three-dimensional frame formed by polymer chains and the internal space of the frame. The polymer chains may be formed by crosslinking bonds containing crosslinkable functional groups contained in the polymer. The crosslinked structure has a three-dimensional shape and a form in which polymer chains are intertwined with each other, and can therefore also be called a three-dimensional network structure.

[0020] Polymer solid electrolyte laminate This invention relates to a polymer solid electrolyte laminate.

[0021] The polymer solid electrolyte laminate according to the present invention comprises a polymer solid electrolyte comprising a polymer containing crosslinkable functional groups, a lithium salt, and a solvent; and a protective layer formed on at least one surface of the polymer solid electrolyte. The polymer solid electrolyte also comprises a crosslinking structure and an amorphous polymer chain containing the crosslinkable functional groups, wherein the crosslinking structure includes (a) crosslinking between crosslinkable functional groups, (b) crosslinking between the crosslinkable functional groups and the solvent, and (c) bonding between the crosslinkable functional groups and the lithium salt. Specifically, the amorphous polymer chain and the lithium salt are contained in the internal space formed in the crosslinking structure, and the lithium salt is contained in a dissociated state.

[0022] Furthermore, the crosslinked structure may be formed by a freezing process as described later. In the freezing process, some of the crosslinkable functional groups contained in the polymer may form localized crystallites, and these localized crystallites may act as crosslinkable junction points to form the crosslinked structure. In this case, the term "crystallites" refers to a shape that resembles entangled threads forming knots, rather than a crystal structure formed by the folding of polymer chains.

[0023] In the present invention, the protective layer is formed on at least one surface of the polymer solid electrolyte and plays a role in protecting the polymer solid electrolyte from mechanical friction and physical damage during the manufacturing process of a battery to which the polymer solid electrolyte is applied, and also plays a role in preventing the phenomenon of changes in the physical properties of the polymer solid electrolyte due to moisture and outside air.

[0024] When the polymer solid electrolyte must be handled in an environment that is well-protected from moisture during the battery manufacturing process, a protective layer that can protect the polymer solid electrolyte from mere mechanical friction and damage is sufficient. In this case, the mechanical strength of the protective layer may be greater than that of the polymer solid electrolyte. The mechanical strength may refer to the modulus.

[0025] The protective layer may be a polymer film with a relatively large modulus compared to the polymer solid electrolyte, or a low-hygroscopic polymer film.

[0026] Polymer films with a relatively large modulus compared to the aforementioned polymer solid electrolytes include polyester film, polycarbonate film (PC), polyethylene film (PE), polymethyl methacrylate film (PMMA), polyetheretherketone film (PEEK), polyethylene naphthalate film (PEN), polyetherimide film (PEI), polyimide film (PI), triacetylcellulose film (TAC), or stretched polyvinyl alcohol film (PVA). The low-hygroscopic polymer film may include cycloolefin polymer (COP) film, polyethylene terephthalate (PET) film, polyacrylate (PAC) film, polyethylene naphthalate (PEN) film, polyvinylidene chloride (PVDC) film, polyvinyl chloride (PVC) film, or ethylene vinyl alcohol copolymer (EVOH) film.

[0027] Furthermore, the low-hygroscopic polymer film may also have excellent moisture-blocking properties.

[0028] The protective layer is not particularly limited as long as it has moisture-blocking and / or low moisture permeability properties. For example, the water vapor transmission rate (WVTR) of the protective layer may be 50 g / m². 2 ·day or less, 40g / m2 ·day or less, 30g / m 2 ·day or less, 20g / m 2 • Less than 10g / m² 2 The water vapor permeability of the protective layer may be less than 50 g / m². 2 If the period is less than or equal to 1 day, the polymer solid electrolyte exhibits the effect of being manufactured in an environment where moisture is almost completely blocked. In this case, there is no loss of ionic conductivity even when exposed to external environmental factors such as moisture, and therefore the manufactured polymer solid electrolyte can exhibit lithium-specific ionic conductivity.

[0029] On the other hand, the water vapor transmission rate of the protective layer is 50 g / m². 2 If the number of days exceeds a certain limit, the function of protecting the polymer solid electrolyte from moisture and / or outside air may decrease, but the ionic conductivity of the polymer solid electrolyte may actually increase due to the influence of moisture. Thus, when the water vapor permeability of the protective layer is high, the reason why the ionic conductivity of the polymer solid electrolyte appears high is not only due to the ionic conductivity of lithium ions, but also due to the protons (H) of the absorbed moisture. + This is because the ionic conductivity (proton hopping) due to water, that is, the ionic conductivity due to water, is added to the result.

[0030] Generally, for the ionic conductivity of a polymer solid electrolyte to directly contribute to improving actual battery performance, it is preferable that the ionic conductivity is represented by lithium ions. If the ionic conductivity of the polymer solid electrolyte is represented by water, its contribution to improving actual battery performance may be negligible or almost nonexistent.

[0031] Therefore, the high ionic conductivity of the polymer solid electrolyte that appears when the water vapor permeability of the protective layer contained in the polymer solid electrolyte is high is not ionic conductivity that appears solely due to lithium ions, and may therefore have little impact on improving actual battery performance. In other words, when the water vapor permeability of the protective layer is high, the moisture content increases, and the ionic conductivity increases due to the moisture, so it is not ionic conductivity due to lithium ions that is relevant to actual battery performance.

[0032] The method for measuring the water vapor transmission rate is not particularly limited, as long as it is a method applicable in this industry to measuring the water vapor transmission rate of an object having a form similar to a film. For example, the water vapor transmission rate may be measured using Mocon's Aquatron equipment. This equipment can measure the concentration of water in nitrogen that has permeated the film by fixing a film between two chambers, introducing water into one chamber while flowing nitrogen into the opposite chamber.

[0033] Furthermore, the protective layer may contain one or more films selected from the group consisting of cycloolefin polymer (COP) film, polyethylene terephthalate (PET) film, polyacrylate (PAC) film, polyethylene naphthalate (PEN) film, polyvinylidene chloride (PVDC) film, polyvinyl chloride (PVC) film, and ethylene vinyl alcohol copolymer (EVOH) film. These films may be polymer films with a non-porous structure.

[0034] Generally, in non-porous polymer films, the permeability of water or gas is known to be influenced by the chemical structure and / or crystallinity of the polymer constituting the film. Furthermore, the interior of the polymer is divided into a crystalline region and an amorphous region, and gas permeation occurs almost entirely in the amorphous region. Since there is a large amount of free volume larger than the size of the permeating gas molecules in the amorphous region, the movement of gas molecules is active, and gas permeation within the polymer film is easy. The gas permeation mechanism in the polymer film can be divided into the process of gas molecules dissolving into the film and the process of gas molecules diffusing into the film.

[0035] Therefore, the gas permeability coefficient (P) of a polymer film can be expressed as the product of the solubility constant (S) and the diffusion coefficient (D), as shown in Equation 1 below.

[0036] [Formula 1] P = S·D

[0037] In this case, for the polymer film to have moisture-blocking and / or low moisture permeability properties, it is preferable that the solubility constant (S) and / or diffusion coefficient (D) are low and the gas permeability coefficient (P) is low. These physical properties may be affected by the type of functional group, bond strength, degree of crystallinity, polarity and orientation, etc.

[0038] Therefore, the present invention can provide a polymer solid electrolyte laminate that can protect the ionic conductivity and mechanical properties of a polymer solid electrolyte by introducing a polymer film with a low water vapor transmission rate (WVTR) as a protective layer for the polymer solid electrolyte.

[0039] The polymer solid electrolyte according to the present invention comprises a polymer containing a crosslinking functional group and a lithium salt.

[0040] Furthermore, the polymer solid electrolyte has a structure comprising a crosslinking structure and an amorphous polymer chain containing the crosslinkable functional group, wherein the crosslinking structure includes (a) crosslinking between crosslinkable functional groups, (b) crosslinking between the crosslinkable functional group and the solvent, and (c) bonding between the crosslinkable functional group and the lithium salt. Specifically, the amorphous polymer chain and the lithium salt are contained in the internal space formed in the crosslinking structure, and the lithium salt is contained in a dissociated state.

[0041] In the present invention, the crosslinking between the crosslinkable functional groups (a) may include hydrogen bonds between the crosslinkable functional groups, for example, the hydrogen bonds may be hydrogen bonds between OH- groups.

[0042] If the crosslinking structure consists only of crosslinking between the (a) crosslinkable functional groups, the polymer solid electrolyte may develop crystallinity, potentially leading to a decrease in ionic conductivity.

[0043] However, since the crosslinking structure includes not only (a) crosslinking between crosslinking functional groups, but also (b) crosslinking between crosslinking functional groups and the solvent, and (c) bonding between crosslinking functional groups and the lithium salt, it is possible to prevent the formation of crystallinity in the polymer solid electrolyte.

[0044] In the present invention, the crosslinking between the (b) crosslinkable functional group and the solvent may include hydrogen bonds, for example, the hydrogen bond may be a hydrogen bond between OH- and H+. In this case, H+ may originate from the aqueous solvent.

[0045] The crosslinking between the crosslinkable functional group and the solvent in (b) above may also refer to hydrogen bonding between the crosslinkable functional group and some of the solvent remaining after the freezing and thawing process.

[0046] Furthermore, the crosslinking between the (b) crosslinkable functional group and the solvent prevents crosslinking between the (a) crosslinkable functional groups, and prevents the crosslinked structure from consisting solely of crosslinking between the (a) crosslinkable functional groups, thereby preventing an increase in the crystallinity of the polymer solid electrolyte.

[0047] In the present invention, the bond between the (c) crosslinkable functional group and the lithium salt may include a bond formed by a Lewis acid-base interaction, for example, the bond may be between OH- and Li+.

[0048] The bond between the crosslinking functional group (c) and the lithium salt is a bond formed by Lewis acid-base interaction and may be a bond similar in form to a metal-ligand bond.

[0049] Furthermore, the bonding of the (c) crosslinkable functional group to the lithium salt prevents crosslinking between the (a) crosslinkable functional groups and the (b) crosslinkable functional group to the solvent, so that the crosslinked structure is not composed solely of crosslinking between the (a) crosslinkable functional groups. This prevents the formation of crystallinity in the polymer solid electrolyte while simultaneously promoting the formation of amorphous polymer chains. As amorphous polymer chains are formed, the mobility of the polymer chains improves, increasing the hopping effect of lithium ions and improving the ionic conductivity of the polymer solid electrolyte.

[0050] In the present invention, the amorphous polymer chain can also be formed by a freezing process as described later, and refers to a polymer chain that does not form crystals by regular folding of the polymer chain and exists in a state of free behavior. That is, the amorphous polymer chain may include a polymer containing a crosslinking functional group that does not form bonds such as those described in (a), (b), and (c).

[0051] Due to the aforementioned cross-linking structure, the polymer solid electrolyte is not easily interrupted or destroyed, and thus can function as an electrolyte support that stably contains lithium ions.

[0052] Furthermore, the amorphous polymer chains allow the polymer solid electrolyte to exhibit elasticity, minimizing its brittleness and resulting in excellent polymer chain mobility. This improves the mobility of lithium ions within the electrolyte, thus providing a polymer solid electrolyte with improved ionic conductivity.

[0053] In the present invention, the crosslinking functional group contained in the polymer containing the crosslinking functional group can have the property of forming a crosslinked structure by forming bonds as shown in (a), (b), and (c) above.

[0054] For example, the crosslinking functional group may include one or more selected from the group consisting of a hydroxyl group, a carboxyl group, and an amide group.

[0055] Furthermore, the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group may be between 80,000 g / mol and 130,000 g / mol, specifically, it may be 80,000 g / mol or more, 83,000 g / mol or more, or 85,000 g / mol or more, and may be 90,000 g / mol or less, 110,000 g / mol or less, or 130,000 g / mol or less. If the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group is less than 80,000 g / mol, the bonds formed by the crosslinking functional group may not be sufficiently formed to obtain a crosslinked structure. If the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group exceeds 130,000 g / mol, the entanglement of polymer chains increases in the polymer solution used in the manufacturing process, and the solvent penetration rate into the interior of the polymer chains decreases. This can accelerate the gelation of the polymer, reducing its solubility and potentially hindering the smooth formation of crosslinked structures by crosslinking functional groups.

[0056] Furthermore, the polymer containing the crosslinking functional group may have the characteristic that the phase separation between the polymer and the solvent occurs smoothly in the polymer solution used in the manufacturing process, and that the bonds of (a), (b), and (c) are successfully formed by the crosslinking functional group contained in the phase-separated polymer during freezing.

[0057] For example, the polymer containing the crosslinking functional group may include one or more selected from the group consisting of polyvinyl alcohol (PVA), gelatin, methylcellulose, agar, dextrin, poly(vinyl pyrrolidone), poly(ethylene oxide), poly(acrylamide), poly(acrylic acid, PAA), starch-carboxymethylcellulose, hyaluronic acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol (PEG). Preferably, the polymer containing the crosslinking functional group may be PVA, which may be advantageous in the manufacturing process of polymer solid electrolytes because, during freezing, the phase separation between the PVA and the solvent is efficiently performed, and the crosslinking structure is formed by the bonds of (a), (b), and (c) derived from the crosslinking functional group of the PVA that has phase-separated from the solvent.

[0058] In the present invention, the lithium salt is contained in a dissociated state within the internal space of the crosslinked bonding structure, and the ionic conductivity of the polymer solid electrolyte can be improved.

[0059] Furthermore, the lithium salt can (c) form a bond between the crosslinking functional group and the lithium salt, thereby preventing the formation of crystallinity in the polymer solid electrolyte while simultaneously promoting the formation of amorphous polymer chains.

[0060] The lithium salt may include one or more selected from the group consisting of (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.

[0061] In the present invention, the molar ratio ([Li] / [G]) of lithium ([Li]) of the lithium salt to the crosslinkable functional group ([G]) of the polymer containing the crosslinkable functional group contained in the polymer solid electrolyte may be more than 0.1 and less than 0.5. Specifically, it may be more than 0.1, 0.2 or more, or 0.3 or more, and may be 0.4 or less or less than 0.5. If the molar ratio ([Li] / [G]) is 0.1 or less, the content of the lithium salt decreases, and the ionic conductivity of the polymer solid electrolyte may decrease. If it is 0.5 or more, the content of the polymer containing the crosslinkable functional group decreases, and the bonds (a), (b) and (c) are not sufficiently formed, resulting in increased crystallinity and possible decrease in ionic conductivity. If the crosslinkable functional group is a hydroxyl group (OH-), [G] can be expressed as [OH] or [O].

[0062] In the present invention, the polymer solid electrolyte may be in the form of a free-standing film or a coating layer. The free-standing film means a film that can maintain its film-like state on its own at room temperature and pressure without the need for a separate support. The coating layer means a layer obtained by coating a substrate. When the polymer solid electrolyte is in the form of a coating layer, the coating layer may be a layer coated on an electrode.

[0063] The freestanding film or coating layer exhibits elasticity, minimizes brittleness, and possesses the properties of a support that stably contains lithium ions, making it a suitable form for a polymer solid electrolyte.

[0064] In the present invention, the polymer solid electrolyte may further contain a liquid electrolyte, and the liquid electrolyte can further improve the ionic conductivity of the polymer solid electrolyte. The liquid electrolyte may also be contained within the internal space of the crosslinking structure.

[0065] The liquid electrolyte may be any liquid electrolyte commonly used in the industry, and its composition is not particularly limited as long as it can be used in a lithium secondary battery. For example, the liquid electrolyte may include a lithium salt and a non-aqueous solvent. The lithium salt may be any of the lithium salts described above. The non-aqueous solvent may also include one or more 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.

[0066] Furthermore, the liquid electrolyte may be present in an amount of 1 to 5% by weight based on the total weight of the polymer solid electrolyte. If the content of the liquid electrolyte is 1% by weight or less, the effect of improving ionic conductivity may be minimal, and if it exceeds 5% by weight, stability may decrease.

[0067] The polymer solid electrolyte described above can be manufactured in a form that includes a polymer chain containing a polymer with crosslinking structures formed by bonds such as (a), (b), and (c) above, which are formed by crosslinking functional groups contained in the polymer, and a polymer having crosslinking functional groups that do not form crosslinks. Due to these morphological characteristics, the polymer solid electrolyte can act as a support that stably contains lithium ions, exhibits elasticity and minimizes brittleness, prevents the formation of crystallinity and improves ionic conductivity.

[0068] Method for manufacturing polymer solid electrolyte laminates The present invention also relates to a method for producing a polymer solid electrolyte laminate, comprising: (S1) adding a lithium salt to a polymer solution containing a crosslinking functional group to form a polymer solid electrolyte forming solution; (S2) applying the polymer solid electrolyte forming solution onto a substrate to form a coating film; (S3) freezing and thawing the coating film to form a polymer solid electrolyte; and (S4) laminating a protective layer on at least one surface of the polymer solid electrolyte.

[0069] In the method for manufacturing the polymer solid electrolyte laminate, a laminate can be manufactured that protects the polymer solid electrolyte from physical contact, moisture, and the outside air by laminating a protective layer on at least one surface of the polymer solid electrolyte.

[0070] Furthermore, in the process of producing the polymer solid electrolyte, without adding a plasticizer which was previously used to reduce the crystallinity of the polymer, the crystallization of the polymer can be prevented by inducing (a) crosslinking between crosslinking functional groups, (b) crosslinking between crosslinking functional groups and the solvent, and (c) bonding between crosslinking functional groups and the lithium salt through a freezing process. As a result, a polymer solid electrolyte with improved ionic conductivity can be produced.

[0071] The method for producing the polymer solid electrolyte according to the present invention will be described in more detail below, step by step.

[0072] In the present invention, in step (S1), a lithium salt can be added to a polymer solution containing a crosslinking functional group to form a polymer solid electrolyte solution. The types and properties of the polymer containing the crosslinking functional group and the lithium salt are as described above.

[0073] The solvent used in the production of the polymer solution may be a polar solvent, such as water. In other words, the polymer solution may be an aqueous polymer solution.

[0074] The concentration of the polymer solution containing the crosslinking functional group can be appropriately adjusted to ensure that the coating process proceeds smoothly when applying the polymer solid electrolyte forming solution to the substrate. For example, the concentration of the polymer solution containing the crosslinking functional group may be 5% to 20%, specifically 5% or more, 7% or more, or 9% or more, or 13% or less, 17% or less, or 20% or less. If the concentration of the polymer solution containing the crosslinking functional group is less than 5%, the concentration is excessively dilute and may run off when applied to the substrate. If it exceeds 20%, it may be difficult to dissolve the lithium salt at the desired concentration in the polymer solution, and the high viscosity may make it difficult to coat it in a uniform thin film.

[0075] In the present invention, in step (S2), the polymer solid electrolyte forming solution can be applied to a substrate to form a coating film.

[0076] The substrate is not particularly limited as long as it can serve as a support to which the polymer solid electrolyte forming solution is applied. For example, the substrate may be stainless steel (SS), polyethylene terephthalate film, polytetrafluoroethylene film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, vinyl chloride copolymer film, polyurethane film, ethylene-vinyl acetate film, ethylene-propylene copolymer film, ethylene-ethyl acrylate copolymer film, ethylene-methyl acrylate copolymer film, or polyimide film.

[0077] Furthermore, the coating method is not particularly limited as long as it is a method that can coat the polymer solid electrolyte forming solution onto the substrate in a film-like manner. 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.

[0078] In the present invention, in step (S3), the coated film can be frozen and thawed to form a crosslinked structure. That is, in the freezing step, the crosslinkable functional groups induce the bonding of (a), (b), and (c), forming a crosslinked structure and creating an amorphous polymer chain.

[0079] In the freezing process, the polymer and water in the aqueous polymer solution containing the crosslinking functional groups used to form the coating film can undergo phase separation. This phase separation may be induced because the hydrogen bonds between water molecules are stronger than the hydrogen bonds between the crosslinking functional groups and water molecules. The water molecules aggregated by the hydrogen bonds between water molecules exist in an ice state (ice phase) during the freezing process. As a result, the number of crosslinking functional groups that form hydrogen bonds through interaction with water molecules is significantly reduced.

[0080] In other words, in the freezing process of the coated film, the polymer and water contained in the polymer aqueous solution must first undergo phase separation, and this phase separation can be induced by hydrogen bonding between water molecules.

[0081] As a result of the phase separation, the interior of the coated film is divided into (i) a polymer-poor phase and (ii) a polymer-rich phase.

[0082] The aforementioned (i) polymer-poor phase is a region containing water molecules that have aggregated due to hydrogen bonds between water molecules, and exists in an ice state, which can also be described as a free water state.

[0083] The (ii) polymer-rich phase is a portion containing a polymer that has undergone phase separation from water. This phase-separated polymer contains crosslinking functional groups that are free from interaction with water molecules. After phase separation, it becomes free and does not form crystals through regular folding, existing in a relatively free, amorphous state, which is called an amorphous polymer chain.

[0084] Furthermore, some of the crosslinking functional groups contained in the phase-separated polymer form localized crystallites. These localized crystallites act as crosslinkable junction points, forming a crosslinked structure that includes the bonds of (a), (b), and (c).

[0085] Furthermore, in the thawing step following the freezing step, the ice contained in the (i) polymer-poor phase melts and evaporates, thereby producing a polymer solid electrolyte with increased free volume.

[0086] Furthermore, the freezing may be carried out under conditions that are appropriate for freezing the coating film. For example, the freezing temperature may be between -30°C and -10°C. Specifically, the freezing temperature may be -30°C or higher, -25°C or higher, or -23°C or higher, or -18°C or lower, -15°C or lower, or -10°C or lower. If the freezing temperature is below -30°C, cracks may occur in the coating film, and if it is above -10°C, phase separation between the polymer and water may not occur sufficiently, making it difficult to form amorphous polymer chain regions. In addition, the freezing may be carried out within a range of 20 to 30 hours, taking into consideration the time required for sufficient freezing.

[0087] Furthermore, the thawing process may be carried out under conditions that appropriately select conditions that allow the frozen coating film to thaw to a degree that it can be used as a polymer solid electrolyte. For example, the thawing temperature may be 15°C to 35°C, or it may be room temperature (25°C). If the thawing temperature is below 15°C, the moisture drying efficiency after thawing (ice melting) may decrease, and if it exceeds 35°C, the coating film may shrink, causing wrinkles or warping.

[0088] Furthermore, in the manufacturing process of the polymer solid electrolyte, crystallization of the polymer can be prevented by inducing the bonding of (a), (b), and (c) without adding a plasticizer, which was previously used to reduce the crystallinity of the polymer. As a result, a polymer solid electrolyte with improved ionic conductivity can be manufactured.

[0089] The steps after (S3) may further include supporting the polymer solid electrolyte on the liquid electrolyte and then drying it. The composition and content of the liquid electrolyte are as described above.

[0090] In the present invention, in step (S4), a protective layer can be laminated on at least one surface of the polymer solid electrolyte to obtain a polymer solid electrolyte laminate. The type of protective layer is as described above.

[0091] After the polymer solid electrolyte is manufactured, a process of laminating the polymer solid electrolyte with electrodes is carried out in a continuous process. In this case, the continuous process may be a continuous process in which the polymer solid electrolyte manufacturing process and the lamination process of the polymer solid electrolyte with electrodes are linked and proceed in a single line, or it may be a continuous process in which the polymer solid electrolyte manufactured in the roll-to-roll process is wound up and temporarily stored, and then unwinded again and fed into the lamination process with electrodes.

[0092] The protective layer may be formed to prevent the physical properties of the polymer solid electrolyte from changing due to moisture and outside air during all processes, including the continuous process and transportation described above.

[0093] The protective layer may be laminated on at least one surface of the polymer solid electrolyte by roll-to-roll lamination, and the polymer solid electrolyte itself may have some stickiness, and the protective layer may adhere due to the adhesive force of the polymer solid electrolyte itself.

[0094] All solid state battery The present invention also relates to an all-solid-state battery comprising a polymer solid electrolyte, wherein the all-solid-state battery comprises a negative electrode, a positive electrode, and a polymer solid electrolyte interposed between the negative electrode and the positive electrode, and the solid electrolyte has the characteristics described above.

[0095] Specifically, the polymer solid electrolyte undergoes a freezing and thawing process, which forms physical crosslinks and reduces its crystallinity, thereby improving its ionic conductivity, making it suitable as an electrolyte for all-solid-state batteries.

[0096] Furthermore, when the polymer solid electrolyte laminate is applied to a battery, the protective layer is removed, and therefore the all-solid-state battery does not contain a protective layer.

[0097] In the present invention, the positive electrode included in the all-solid-state battery includes a positive electrode active material layer, and the positive electrode active material layer may be formed on one surface of the positive electrode current collector.

[0098] The positive electrode active material layer comprises a positive electrode active material, a binder, and a conductive material.

[0099] Furthermore, the positive electrode active material is not particularly limited as long as it is a material capable of reversibly intercalating and releasing lithium ions, for example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), Li[Ni x Co y Mn z M v ]O2(In the above formula, M is one 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 comprises Mn and one or more elements selected from the group consisting of Ni, Co, Fe, Cr, V, Cu, Zn, and Ti; M' is one or more elements selected from the group consisting of Al, Mg, and B; and A is one or more elements selected from the group consisting of P, F, S, and N.) A layered compound such as, or a compound substituted with one or more transition metals; chemical formula Li 1+y Mn 2-y Lithium manganese oxides such as O4 (where y is 0 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 as MyO2 (where 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 as O2 (where M is Co, Ni, Fe, Cr, Zn, or Ta, and y is 0.01 to 0.1) or Li2Mn3MO8 (where M is Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which part of the Li in the chemical formula is substituted with an alkaline earth metal ion; disulfide compounds; Fe2(MoO4)3, etc., are examples, but are not limited to these.

[0100] Furthermore, the positive electrode active material may be present in an amount of 40 to 80% by weight based on the total weight of the positive electrode active material layer. Specifically, the content of the positive electrode active material may be 40% or more by weight, 50% or more by weight, or 70% or less by weight, or 80% or less by weight. If the content of the positive electrode active material is less than 40% by weight, the connectivity between the wet positive electrode active material layer and the dry positive electrode active material layer may become insufficient, and if it exceeds 80% by weight, the mass transfer resistance may increase.

[0101] Furthermore, the binder contains components that assist in the bonding of the positive electrode active material to conductive materials and to the current collector, such as styrene-butadiene rubber, acrylic styrene-butadiene rubber, acrylonitrile copolymer, acrylonitrile-butadiene rubber, nitrile-butadiene rubber, acrylonitrile-styrene-butadiene copolymer, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene / propylene copolymer, polybutadiene, polyethylene oxide, chlorosulfonated polyethylene, polyvinylpyrrolidone, polyvinylpyridine, polyvinyl alcohol, and polyvinyl acetate. The binder may contain one or more selected from the group consisting of polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethylcellulose, hydroxypropylcellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylcellulose, cyanoethyl scrophularis, polyester, polyamide, polyether, polyimide, polycarboxylate, polycarboxylic acid, polyacrylic acid, polyacrylate, lithium polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyurethane, polyvinylidene fluoride, and poly(vinylidene fluoride)-hexafluoropropene. Preferably, the binder may contain one or more selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethylcellulose, polyacrylic acid, lithium polyacrylate, and polyvinylidene fluoride.

[0102] Furthermore, the binder may be present in an amount of 1% to 30% by weight based on the total weight of the positive electrode active material layer. Specifically, the binder content may be 1% or more by weight, 3% or more by weight, 15% or less by weight, or 30% or less by weight. If the binder content is less than 1% by weight, the adhesive strength between the positive electrode active material and the positive electrode current collector may decrease. If it exceeds 30% by weight, the adhesive strength will improve, but the content of the positive electrode active material will decrease accordingly, potentially reducing the battery capacity.

[0103] Furthermore, the conductive material is not particularly limited as long as it prevents side reactions in the internal environment of the all-solid-state battery, does not induce chemical changes in the battery, and has excellent electrical conductivity. Typically, graphite or conductive carbon may be used, for example: graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, Denka black, thermal black, channel black, furnace black, lamp black, and summer black; carbon-based materials whose crystalline structure is graphene or graphite; conductive fibers such as carbon fibers and metal fibers; carbon fluoride; metal powders such as aluminum powder and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive oxides such as titanium oxide; and conductive polymers such as polyphenylene derivatives. These may be used individually or in combination of two or more, but are not necessarily limited to these.

[0104] The conductive material may be included in an amount of 0.5% to 30% by weight based on the total weight of the positive electrode active material layer. Specifically, the content of the conductive material may be 0.5% or more by weight, 1% or more by weight, 20% or less by weight, or 30% or less by weight. If the content of the conductive material is too low, less than 0.5% by weight, it may be difficult to expect an improvement in electrical conductivity, or the electrochemical properties of the battery may deteriorate. If it is too high, exceeding 30% by weight, the amount of positive electrode active material will be relatively small, and the capacity and energy density may decrease. The method of incorporating the conductive material into the positive electrode is not particularly limited, and conventional methods known in the art, such as coating the positive electrode active material, may be used.

[0105] Furthermore, the positive electrode current collector supports the positive electrode active material layer and plays a role in transferring electrons between the external conductor and the positive electrode active material layer.

[0106] The positive electrode current collector is not particularly limited as long as it does not induce chemical changes in the all-solid-state battery and has high electronic conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, silver, etc., or aluminum-cadmium alloy may be used as the positive electrode current collector.

[0107] The positive electrode current collector may have a fine uneven surface or employ a three-dimensional porous structure to strengthen the bonding force with the positive electrode active material layer. As a result, the positive electrode current collector may include various forms such as film, sheet, foil, mesh, net, porous material, foam, and nonwoven fabric.

[0108] The positive electrode described above can be manufactured by conventional methods. Specifically, it can be manufactured by mixing a positive electrode active material, a conductive material, and a binder in an organic solvent to produce a composition for forming a positive electrode active material layer, which is then coated onto a positive electrode current collector and dried, and then selectively compress-molded onto the current collector to improve electrode density. In this case, it is preferable to use an organic solvent that can uniformly disperse the positive electrode active material, binder, and conductive material and evaporates easily. Examples include acetonitrile, methanol, ethanol, tetrahydrofuran, water, and isopropyl alcohol.

[0109] In the present invention, the negative electrode included in the all-solid-state battery includes a negative electrode active material layer, and the negative electrode active material layer may be formed on one surface of the negative electrode current collector.

[0110] The negative electrode active material is lithium (Li + The material may include a substance that can be reversibly intercalated or deintercalated, a substance that can react with lithium ions to reversibly form a lithium-containing compound, or a lithium metal or lithium alloy.

[0111] The aforementioned lithium ion (Li +The material that can reversibly insert or remove the lithium ion (Li) may be, for example, crystalline carbon, amorphous carbon, or a mixture thereof. + A substance that can reversibly form a lithium-containing compound by reacting with ) may be, for example, tin oxide, titanium nitrate, or silicon. The lithium alloy may 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).

[0112] Preferably, the negative electrode active material may be lithium metal, and specifically, it may be in the form of a lithium metal thin film or lithium metal powder.

[0113] The negative electrode active material may be present in an amount of 40 to 80% by weight based on the total weight of the negative electrode active material layer. Specifically, the content of the negative electrode active material may be 40% by weight or more, or 50% by weight or more, or 70% by weight or less, or 80% by weight or less. If the content of the negative electrode active material is less than 40% by weight, the connectivity between the wet negative electrode active material layer and the dry negative electrode active material layer may be insufficient, and if it exceeds 80% by weight, the mass transfer resistance may increase.

[0114] Furthermore, the binder is as described above for the positive electrode active material layer.

[0115] Furthermore, the conductive material is as described above for the positive electrode active material layer.

[0116] Furthermore, the negative electrode current collector is not particularly limited as long as it does not induce a chemical change in the battery and is conductive. 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., or aluminum-cadmium alloy. Also, similar to the positive electrode current collector, the negative electrode current collector may be made of various forms such as films, sheets, foils, nets, porous materials, foams, or nonwoven fabrics with fine irregularities formed on their surface.

[0117] The method for manufacturing the negative electrode is not particularly limited, and the negative electrode active material layer may be formed on the negative electrode current collector using a layer or film formation method commonly used in the industry. For example, methods such as crimping, coating, and vapor deposition may be used. Furthermore, the negative electrode of the present invention is also included in the case where a metallic lithium thin film is formed on a metal plate by initial charging after the battery has been assembled without a lithium thin film on the negative electrode current collector.

[0118] Furthermore, the present invention provides a battery module including the all-solid-state battery as a unit battery, a battery pack including the battery module, and a device including the battery pack as a power source.

[0119] Specific examples of the device include, but are not limited to, power tools powered by battery-powered motors; electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs); electric two-wheeled vehicles including electric bicycles (E-bikes) and electric scooters; electric golf carts; and power storage systems. The following examples illustrate the present invention, but are not limited to those described above. It will be apparent to those skilled in the art that various changes and modifications are possible within the scope of the invention and its technical concept, and that such changes and modifications may fall within the scope of the attached claims.

[0120] In the following examples and comparative examples, polymer solid electrolytes were produced depending on whether or not a protective layer and a freeze / thaw process were applied, as shown in Table 1 below.

[0121] [Table 1]

[0122] Example 1 A 10% aqueous solution of PVA (Mw: 89,000 g / mol; degree of hydrolysis: >99%) was mixed with water. LiTFSI was added to the aqueous PVA solution and stirred to prepare a solution containing PVA, a polymer having crosslinking functional groups, and LiTFSI, a lithium salt. At this time, the molar ratio ([Li] / [OH]) of the crosslinking functional group "OH" of PVA to the "Li" of the lithium salt was set to 0.4.

[0123] The aforementioned solution was applied to a substrate, SS foil, by a bar coating method to form a coating film. The film was then frozen at -20°C for 24 hours and thawed at 25°C to produce a polymer solid electrolyte.

[0124] A polymer solid electrolyte laminate was manufactured by laminating a cycloolefin polymer (COP) film (Zeon Film, Japan / JEONOR (50 μm)) as a protective layer on one surface of the polymer solid electrolyte. The WVTR of the COP film was 0.5 g / m². 2 It is a day.

[0125] Example 2 A polymer solid electrolyte laminate was manufactured in the same manner as in Example 1, except that a polyethylene terephthalate (PET) film (50 μm, Toyobo, Japan / T-PET) was used as the protective layer. The WVTR of the PET film was 15 g / m². 2 It is a day.

[0126] Example 3 A polymer solid electrolyte laminate was manufactured in the same manner as in Example 1, except that a polyacrylate (PAC) film (polyethylene terephthalate film (50 μm), LG Chem, Korea / JEONOR (50 μm)) was used as a protective layer. The WVTR of the PAC film was 50 g / m². 2 It is a day.

[0127] Example 4 A polymer solid electrolyte laminate was manufactured in the same manner as in Example 1, except that a triacetyl cellulose (TAC) film (LG Chem, Korea / JEONOR (50 μm)) was used as a protective layer. The WVTR of the TAC film was 300 g / m². 2 It is a day.

[0128] Comparative Example 1 A polymer solid electrolyte that is not a laminate was produced in the same manner as in Example 1, except that a protective layer was not laminated.

[0129] Comparative Example 2 A polymer solid electrolyte laminate was produced in the same manner as in Example 1, except that a solution containing PVA, a polymer having crosslinking functional groups, and LiTFSI, a lithium salt, was applied to a substrate SS foil and then dried at 80°C.

[0130] Experimental Example 1 The polymer solid electrolyte laminates produced in the examples and comparative examples were stored in a moisture-exposed environment for 72 hours. After removing the protective layer, the mechanical strength, ionic conductivity, and change in ionic conductivity due to moisture (△σi) of the polymer solid electrolyte were measured using the method described below. The measurement results are shown in Table 2 below.

[0131] (1) Mechanical strength The mechanical strength of the aforementioned polymer solid electrolyte is the modulus measured by Dynamic Mechanical Analysis (DMA) (TA Instrument, RSA3).

[0132] (2) Ionic conductivity To measure the aforementioned ionic conductivity, 1.7671 cm 2 The polymer solid electrolyte was punched out into a circular shape, and the punched-out polymer solid electrolyte was placed between two pieces of stainless steel (SS) to manufacture a coin cell.

[0133] Using an electrochemical impedance spectrometer (EIS, VM3, Bio Logic Science Instrument), the resistance was measured at 25°C with an amplitude of 10 mV and a scan range of 500 kHz to 20 MHz. The ionic conductivity of the polymer solid electrolyte was then calculated using Equation 2 below.

[0134]

number

[0135] In the above formula 2, σ i R is the ionic conductivity (S / cm) of the polymer solid electrolyte, R is the resistance (Ω) of the polymer solid electrolyte measured by the electrochemical impedance spectrometer, L is the thickness (μm) of the polymer solid electrolyte, and A is the area (cm²) of the polymer solid electrolyte. 2 ) means.

[0136] In this case, the ionic conductivity is the sum of the ionic conductivity due to lithium ions and the ionic conductivity due to water.

[0137] (3) Change in ionic conductivity due to moisture (△σ x , %) The WVTR of the protective layer formed on the polymer solid electrolyte in Example 1 is 0.5 g / m². 2 The polymer solid electrolyte of Example 1 exhibits the level of ionic conductivity of a polymer solid electrolyte manufactured in an environment completely free of moisture. That is, the ionic conductivity of the polymer solid electrolyte of Example 1 is identical to the ionic conductivity due to lithium ions, and the ionic conductivity due to moisture may be substantially zero.

[0138] As shown in Equation 3 below, using the ionic conductivity of the polymer solid electrolyte of Example 1 as a reference, the change in ionic conductivity due to water (△σ) of the polymer solid electrolytes of Examples 2-4 and Comparative Example 1 is calculated as follows: x ) was calculated as a percentage.

[0139]

number

[0140] The aforementioned x is Example 2, 3, 4 or Comparative Example 1. For example, △σ 実施例2 This represents the change in ionic conductivity due to moisture in Example 2 compared to Example 1.

[0141] [Table 2]

[0142] As shown in Table 2 above, it was found that when exposed to a humid environment, the polymer solid electrolyte without a protective layer, as in Comparative Example 1, showed a decrease in mechanical strength (modulus) to 1 / 10th of that of Example 1 due to moisture absorption, while its ionic conductivity increased by approximately four times. However, this ionic conductivity is not the lithium ion conductivity relevant to battery performance, but rather the result of the added ionic conductivity due to moisture, and therefore is not an ionic conductivity that is advantageous for the physical properties of the polymer solid electrolyte that are relevant to actual battery performance.

[0143] Furthermore, as in Comparative Example 2, when a simple drying process was performed instead of a freezing and thawing process, it was not possible to form a uniform polymer solid electrolyte sample on the substrate. In addition, due to the viscous and fragmented properties of the sample, it was not possible to peel the sample from the substrate, and therefore it was not possible to measure its properties.

[0144] Although the present invention has been described above with limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations can be made by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below.

Claims

1. A polymer solid electrolyte laminate comprising a polymer solid electrolyte and a protective layer formed on at least one surface of the polymer solid electrolyte, The polymer solid electrolyte comprises a polymer containing a crosslinking functional group, a lithium salt, and a solvent. The polymer solid electrolyte comprises a crosslinking structure and an amorphous polymer chain containing the crosslinking functional group. The aforementioned crosslinking structure includes (a) crosslinking between crosslinking functional groups, (b) crosslinking between a crosslinking functional group and a solvent, and (c) bonding between a crosslinking functional group and a lithium salt. The solvent is water. The polymer solid electrolyte laminate has a water vapor transmission rate (WVTR) of 50 g / m²·day or less in the protective layer.

2. The protective layer is a polymer film with a relatively large modulus compared to the polymer solid electrolyte, or a low-hygroscopic polymer film. Polymer films with a relatively large modulus compared to the aforementioned polymer solid electrolytes include polyester film (polyester), polycarbonate film (polycarbonate, PC), polyethylene film (polyethylene, PE), polymethyl methacrylate film (polymethylmethacrylate, PMMA), polyetheretherketone film (polyetheretherketone, PEEK), polyethylene naphthalate film (polyethylene naphthalate, PEN), polyetherimide film (polyetherimide, PEI), polyimide film (polyimide, PI), triacetylcellulose film (triacetylcellulose, TAC), or stretched polyvinyl alcohol film (polyvinyl alcohol, PVA). The polymer solid electrolyte laminate according to claim 1, wherein the low-hygroscopic polymer film includes a cycloolefin polymer (COP) film, a polyethylene terephthalate (PET) film, a polyacrylate (PAC) film, a polyethylene naphthalate (PEN) film, a polyvinylidene chloride (PVDC) film, a polyvinyl chloride (PVC) film, or an ethylene vinyl alcohol copolymer (EVOH) film.

3. The crosslinking between the crosslinkable functional groups includes hydrogen bonding, The crosslinking bond between the crosslinkable functional group and the solvent in (b) includes a hydrogen bond, The polymer solid electrolyte laminate according to claim 1, wherein the bond between the crosslinkable functional group and the lithium salt includes a bond formed by Lewis acid-base interaction.

4. The polymer solid electrolyte laminate according to claim 1, wherein the crosslinking functional group comprises one or more selected from the group consisting of a hydroxyl group, a carboxyl group, and an amide group.

5. The polymers containing the aforementioned crosslinking functional groups include polyvinyl alcohol (PVA), gelatin, methylcellulose, agar, dextrin, poly(vinylpyrrolidone), poly(ethylene oxide), poly(acrylamide), polyacrylic acid (PAA), starch-carboxymethylcellulose, and hyaluronic acid-methylcellulose. The polymer solid electrolyte laminate according to claim 1, comprising one or more selected from the group consisting of acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol.

6. The polymer solid electrolyte laminate according to claim 1, wherein the weight-average molecular weight (Mw) of the polymer containing the crosslinking functional group is 80,000 g / mol to 130,000 g / mol.

7. The polymers containing the aforementioned crosslinking functional groups include polyvinyl alcohol (PVA), gelatin, methylcellulose, agar, dextrin, poly(vinylpyrrolidone), poly(ethylene oxide), poly(acrylamide), starch-carboxymethylcellulose, and hyaluronic acid-methylcellulose. The polymer solid electrolyte laminate according to claim 1, comprising one or more selected from the group consisting of acid-methylcellulose, chitosan, poly(N-isopropylacrylamide), and amino-terminated polyethylene glycol.

8. The lithium salt is (CF ３ SO ２ ), ２ NLi (Lithium bis(trifluoromethanesulphonyl)imide, LiTFSI), (FSO ２ ), ２ NLi (Lithium bis(fluorosulphonyl)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 The polymer solid electrolyte laminate according to claim 1, which contains one or more selected from the group consisting of

9. The polymer solid electrolyte laminate according to claim 1, wherein the molar ratio ([Li] / [G]) of the crosslinking functional group ([G]) of the polymer to the lithium ([Li]) of the lithium salt is greater than 0.1 and less than 0.

5.

10. The polymer solid electrolyte laminate according to claim 1, wherein the polymer solid electrolyte is in the form of a freestanding film or a coating layer.

11. The polymer solid electrolyte laminate according to claim 1, wherein the polymer solid electrolyte further comprises a liquid electrolyte.

12. (S1) A step of adding a lithium salt to an aqueous polymer solution containing a crosslinking functional group to form a polymer solid electrolyte solution; (S2) A step of applying the polymer solid electrolyte forming solution onto a substrate to form a coating film; (S3) The step of freezing and thawing the coated film to form a polymer solid electrolyte; and (S4) Laminating a protective layer on at least one surface of the polymer solid electrolyte; Includes, A method for manufacturing a polymer solid electrolyte laminate, wherein the water vapor transmission rate (WVTR) of the protective layer is 50 g / m²·day or less.

13. The polymer solid electrolyte includes a crosslinking structure, The aforementioned crosslinking structure includes (a) crosslinking between crosslinking functional groups, (b) crosslinking between a crosslinking functional group and a solvent, and (c) bonding between a crosslinking functional group and a lithium salt. The crosslinking between the crosslinkable functional groups includes hydrogen bonding, The crosslinking bond between the crosslinkable functional group and the solvent in (b) includes a hydrogen bond, The method for producing a polymer solid electrolyte laminate according to claim 12, wherein the bond between the crosslinkable functional group and the lithium salt includes a bond formed by Lewis acid-base interaction.

14. The method for producing a polymer solid electrolyte laminate according to claim 12, wherein the freezing is performed at -30°C to -10°C.

15. The method for producing a polymer solid electrolyte laminate according to any one of claims 12 to 14, wherein the thawing is performed at 15°C to 35°C.

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