Polymer solid electrolyte and all-solid-state battery containing the same

Abstract

The present invention relates to a polymer solid electrolyte and an all-solid-state battery including the same. When the polymer solid electrolyte is manufactured, an ion-conductive polymer and polymer particles having a density similar to that of the ion-conductive polymer are used as raw materials, thereby improving the uniformity and strength of the manufactured polymer solid electrolyte.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2021-0180710 dated December 16, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a polymer solid electrolyte and an all-solid-state battery including the same. [Background technology]

[0003] Currently, various batteries that can overcome the limitations of lithium secondary batteries are being researched from the viewpoints of battery capacity, safety, output, size increase, and miniaturization.

[0004] Typically, research is ongoing into metal-air batteries, which have a much larger theoretical capacity than current lithium secondary batteries, all-solid batteries, which are safe and do not pose a risk of explosion, supercapacitors, NaS batteries or RFBs (redox flow batteries), which are large-scale batteries, and thin film batteries, which are ultra-small.

[0005] Among these, all-solid-state batteries are batteries that replace the liquid electrolyte used in existing lithium secondary batteries with a solid, and because they do not use flammable solvents, they can significantly improve safety by eliminating the risk of fire or explosion caused by the decomposition reaction of conventional electrolytes.In addition, because lithium metal or lithium alloys can be used as the anode material, they have the advantage of dramatically improving the energy density relative to the mass and volume of the battery.

[0006] As such, all-solid-state batteries are attracting attention as next-generation lithium secondary batteries due to their superior safety and the ability to simplify their manufacturing process.

[0007] However, as electronic devices have recently become thinner, there has been an increasing demand for thin-film solid electrolytes to be used in all-solid-state batteries. However, as solid electrolytes become thinner, their strength decreases.

[0008] Therefore, in order to manufacture a high-strength solid electrolyte thin film, a technology has been developed in which inorganic materials are added to the high-strength solid electrolyte thin film. However, this technology has the problem of reducing the uniformity of the solid electrolyte depending on the density ratio between the inorganic material and the polymer contained in the solid electrolyte. When the uniformity of the solid electrolyte is reduced, differences in the concentration and / or speed of ions moving through the solid electrolyte membrane occur. This can lead to non-uniform reactions at the anode, or in severe cases, the formation of lithium dendrites, which can reduce the lifespan and stability of the battery.

[0009] In addition, a technique of attaching a separator to a solid electrolyte has been developed to manufacture a high-strength solid electrolyte thin film, but this technique has the problem of reducing the uniformity of the solid electrolyte due to the different interfaces between the separator and the solid electrolyte.

[0010] Therefore, there is a demand for the development of a manufacturing technology for a uniform, high-strength solid electrolyte in the form of a thin film. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 2020-0036918 Summary of the Invention [Problem to be solved by the invention]

[0012] As a result of extensive research to solve the above problems, the present inventors have found that the strength of the prepared polymer solid electrolyte can be improved by using polymer particles as an additive when preparing a polymer solid electrolyte containing an ion-conductive polymer, and by using polymer particles having a density similar to that of the ion-conductive polymer.

[0013] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high-strength polymer solid electrolyte in the form of a thin film and a method for producing the same.

[0014] Another object of the present invention is to provide an all-solid-state battery including a high-strength polymer solid electrolyte in the form of a thin film. [Means for solving the problem]

[0015] To achieve the above object, the present invention provides a polymer solid electrolyte comprising an ion-conducting polymer, a lithium salt, and polymer particles compatible with the ion-conducting polymer, wherein the density ratio (Δd) of the ion-conducting polymer to the polymer particles is 3 or less.

[0016] The density ratio (Δd) may be 0.5 to 2.5 and may be calculated according to Equation 1: <Formula 1> △d=d2 / d1 In the above formula 1, d1 is the density of the ion-conductive polymer, and d2 is the density of the polymer particles.

[0017] The ion-conductive polymer may include one or more selected from the group consisting of polyether polymers, polycarbonate polymers, acrylate polymers, polysiloxane polymers, phosphagen polymers, polyethylene derivatives, alkylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionically dissociable groups, polypyrrole, polyaniline (PANI), and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).

[0018] The lithium salt is Li+ X - and the anion (X - ) is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - or (CF3CF2SO2)2N - may be.

[0019] The polymer particles may include an engineering plastic resin, and the engineering plastic resin may include at least one selected from the group consisting of polyphenylene sulfide (PPS), polyetheretherketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polypropylene, polyethylene, and poly(methyl methacrylate).

[0020] The polymer solid electrolyte may include 45 to 95 wt % of the ion-conducting polymer, 2 to 50 wt % of the lithium salt, and 2 to 35 wt % of the polymer particles.

[0021] The particle size (d 50 ) may be less than 20 μm.

[0022] The solid electrolyte may be in the form of a thin film having a thickness of 5 μm to 100 μm.

[0023] The present invention also provides a method for preparing a polymer solid electrolyte, the method comprising the steps of: (S1) adding an ion-conductive polymer, a lithium salt, and the ion-conductive polymer and polymer particles to an organic solvent to form a mixed solution; (S2) coating the mixed solution onto a substrate; and (S3) drying the coating layer formed on the substrate to form a polymer solid electrolyte, wherein the density ratio (Δd) of the ion-conductive polymer to the polymer particles is 3 or less. The organic solvent may include at least one selected from the group consisting of alcohol-based solvents, glycol ether-based solvents, glycol ether ester-based solvents, ketone-based solvents, hydrocarbon-based solvents, lactic acid-based solvents, ester-based solvents, aprotic sulfoxide-based solvents, and nitrile-based solvents.

[0024] The present invention also provides an all-solid-state battery containing the solid electrolyte. [Effects of the Invention]

[0025] According to the present invention, when preparing a polymer solid electrolyte, an ion-conductive polymer and polymer particles having a density ratio small relative to the ion-conductive polymer are used as raw materials, thereby improving the uniformity of the polymer solid electrolyte and providing the prepared polymer solid electrolyte with a thin film shape and high strength. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a schematic diagram showing the structure of a polymer solid electrolyte according to an embodiment of the present invention. FIG. [Figure 2] 1 is a schematic diagram illustrating a process for preparing a polymer solid electrolyte according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will now be described in more detail to aid in understanding the invention.

[0028] The terms and words used in this specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meanings, but should be interpreted in a meaning and concept that corresponds to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to best explain his / her invention.

[0029] Polymer solid electrolyte The present invention relates to a polymer solid electrolyte, which includes an ion-conductive polymer, a lithium salt, and polymer particles. The density ratio (Δd), which is defined as the ratio of the densities of the ion-conductive polymer and the polymer particles, may be 3 or less, specifically, 0.5 to 2.5. If the density ratio is less than 0.5 or more than 2.5, phase separation may occur during the mixing and drying processes, resulting in a non-uniform membrane.

[0030] In the present invention, by limiting the density ratio of the ion-conductive polymer to the polymer particles within a certain range, phase separation between the ion-conductive polymer and the polymer particles in the polymer solid electrolyte can be prevented, thereby improving the uniformity and strength of the polymer solid electrolyte.

[0031] The density ratio (Δd) defined as the ratio of the densities of the ion-conductive polymer and the polymer particles is calculated by the following Equation 1: <Formula 1> △d=d2 / d1 In the above formula 1, d1 is the density of the ion-conductive polymer, and d2 is the density of the polymer particles.

[0032] FIG. 1 is a schematic diagram showing the structure of a polymer solid electrolyte according to one embodiment of the present invention.

[0033] 1, the polymer solid electrolyte 1 has a structure in which polymer particles 20 are uniformly dispersed within a polymer solid electrolyte matrix 10. Specifically, the polymer particles 20 may be uniformly dispersed in an embedded state within an ion-conductive polymer matrix and / or polymer chains 11.

[0034] In the present invention, the polymer may be an ion-conducting polymer, but is not limited thereto, and may be a polymer that can be included in the solid electrolyte and serve to form a path through which ions are transported.

[0035] The ion-conductive polymer may be at least one selected from the group consisting of polyether-based polymers, polycarbonate-based polymers, acrylate-based polymers, polysiloxane-based polymers, phosphagen-based polymers, polyethylene derivatives, alkylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionically dissociable groups, polypyrrole, polyaniline (PANI), and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). Preferably, the ion-conductive polymer may be polyethylene oxide (PEO).

[0036] Furthermore, the ion-conducting polymer may be included in an amount of 45 to 95 wt % based on the total weight of the polymer solid electrolyte. Specifically, the content of the ion-conducting polymer may be 45 wt % or more, 50 wt % or more, 60 wt % or more, or 70 wt % or more, or 80 wt % or less, 85 wt % or less, 90 wt % or less, or 95 wt % or less. If the content of the ion-conducting polymer is less than 50 wt %, the volume of the ion-conducting polymer may be reduced, resulting in low ion conductivity. If the content exceeds 95 wt %, the performance improvement effect of the polymer solid electrolyte may be negligible.

[0037] In the present invention, the polymer particles may include a polymer compatible with the ion-conducting polymer. The use of such polymer particles can prevent phase separation with the ion-conducting polymer included in the polymer solid electrolyte, thereby improving the uniformity of the polymer solid electrolyte and improving its strength. In this case, the degree of compatibility between the ion-conducting polymer and the polymer particles can be determined by their density ratio. By limiting the density ratio of the ion-conducting polymer to the polymer particles within a specific range, phase separation can be prevented and the uniformity of the polymer solid electrolyte can be improved.

[0038] The polymer particles may include an engineering plastic resin. The engineering plastic resin may include at least one selected from the group consisting of polyphenylene sulfide (PPS), polyetheretherketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyoxymethylene, polycarbonate, polypropylene, polyethylene, and poly(methyl methacrylate). The molecular weight of the engineering plastic resin may be 100,000 Da to 10,000,000 Da.

[0039] The density of the polymer particles is 0.8 to 2.2 g / cm 3In consideration of the density ratio (Δd) with respect to the ion-conductive polymer, polymer particles having a density that satisfies the above range can be appropriately selected and used.

[0040] In addition, the ion-conducting polymer may be included in an amount of 2 to 35 wt% based on the total weight of the polymer solid electrolyte, and specifically, the content of the ion-conducting polymer may be 5 wt% or more, 10 wt% or more, or 20 wt% or more, or 30 wt% or less, 32 wt% or less, or 35 wt% or less. If the content of the ion-conducting polymer is less than 5 wt%, the performance improvement of the composite may be negligible, and if it exceeds 35 wt%, the ion conductivity may be reduced.

[0041] In addition, the particle size of the polymer particles may be 50 nm to 20 μm. If the particle size is less than 50 nm, the specific surface area is large, which may cause aggregation problems, and if the particle size is more than 20 μm, it may cause problems in thinning the electrolyte membrane.

[0042] The strength of the polymer particles may be greater than that of the ion-conducting polymer. Specifically, the Young's modulus (E) of the polymer particles may be 1500 MPa to 4 GPa. If the Young's modulus is less than 1500 MPa, the strength improvement effect is negligible, and if it exceeds 4 GPa, the process may be difficult to proceed. The strength of the ion-conducting polymer refers to the strength of a specimen of the ion-conducting polymer.

[0043] In the present invention, the lithium salt can improve the ionic conductivity of the polymer solid electrolyte.

[0044] The lithium salt is an ionizable lithium salt, and Li + X - The anion (X - ) is not particularly limited as long as it can form a salt with a lithium cation. For example, the anion (X - ) is F - , Cl- , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - or (CF3CF2SO2)2N - may be.

[0045] The lithium salt may be included in an amount of 2 to 50 wt % based on the total weight of the polymer solid electrolyte. Specifically, the content of the lithium salt may be 5 wt % or more, 10 wt % or more, or 20 wt % or less, 30 wt % or less, 40 wt % or less, or 50 wt % or less. If the content of the lithium salt is less than 5 wt %, the ionic conductivity of the solid electrolyte may decrease. If the content of the lithium salt is more than 50 wt %, the content of the ion-conducting polymer may be relatively reduced, resulting in a decrease in ionic conductivity or precipitation of the lithium salt.

[0046] In the present invention, the thickness of the polymer solid electrolyte may be 5 μm to 100 μm, and the thickness is reduced compared to that of a typical polymer solid electrolyte, resulting in a thin polymer solid electrolyte form with improved thickness uniformity. Specifically, the thickness of the polymer solid electrolyte may be 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more, or 32 μm or less, 40 μm or less, 60 μm or less, 80 μm or less, or 100 μm or less.

[0047] If the thickness of the polymer solid electrolyte is less than 5 μm, durability may be reduced, and if it exceeds 100 μm, it may act as a resistor during battery operation or the energy density may be reduced.

[0048] Method for producing solid electrolyte The present invention also relates to a method for producing a polymer solid electrolyte, the method including the steps of: (S1) adding an ion-conducting polymer, a lithium salt, and polymer particles compatible with the ion-conducting polymer to an organic solvent to form a mixed solution; (S2) coating the mixed solution onto a substrate; and (S3) drying the coating layer formed on the substrate to form a polymer solid electrolyte.

[0049] FIG. 2 is a schematic diagram showing a method for manufacturing a solid electrolyte according to an embodiment of the present invention. Each step of the method for manufacturing a solid electrolyte according to the present invention will be described in more detail with reference to FIG.

[0050] In the step (S1), the ion-conducting polymer, the lithium salt, and the polymer particles may be added to an organic solvent to form a mixed solution, the types and contents of which are as described above.

[0051] The organic solvent may be capable of dissolving the polymer and the lithium salt, dispersing the polymer particles, and being volatilized during drying.

[0052] The organic solvent may be at least one volatile organic solvent selected from the group consisting of alcohol solvents, glycol ether solvents, glycol ether ester solvents, ketone solvents, hydrocarbon solvents, lactic acid solvents, ester solvents, aprotic sulfoxide solvents, and nitrile solvents. Specifically, the volatile organic solvent may include at least one selected from the group consisting of acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone, methyl ethyl ketone, and cyclohexane.

[0053] In addition, the concentration of the mixed solution may be appropriately selected within the range of 20 to 40% so that the coating process in step (S2) described below can be smoothly performed.

[0054] In the present invention, in the step (S2), the mixed solution may be applied onto a substrate to form a coating layer.

[0055] The substrate may be in the form of a foil, which may be a metal selected from the group consisting of aluminum, copper, SUS, and Ni, or may be in the form of a thin film of a polymer release film such as polyethylene terephthalate (PET), etc. Use of the substrate is advantageous for producing a polymer solid electrolyte in the form of a uniform free-standing film.

[0056] 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, but is not limited thereto as long as it is a coating method that can form a coating layer on the substrate.

[0057] In the present invention, in step (S3), the coating layer formed on the substrate may be dried to prepare a polymer solid electrolyte.

[0058] The drying method is not particularly limited as long as it can evaporate the organic solvent. For example, the drying may be performed at 100° C. or less.

[0059] After the solid electrolyte is produced, the substrate can be separated and removed.

[0060] All solid state battery The present invention also relates to an all-solid-state battery including the above-described solid electrolyte, and the all-solid-state battery may include a positive electrode, a negative electrode, and the solid electrolyte interposed therebetween.

[0061] In the present invention, the positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector.

[0062] The positive electrode active material layer includes a positive electrode active material, a binder, and a conductive material.

[0063] The positive electrode active material is not particularly limited as long as it is a material capable of reversibly absorbing and releasing lithium ions. For example, lithium cobalt oxide (LiCoO), lithium nickel oxide (LiNiO), Li[Ni x Co y Mn z M v ]O2 (wherein M is any 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, and x+y+z+v=1), Li (Li a M b-a-b' M' b' )O 2-c A c (wherein 0≦a≦0.2, 0.6≦b≦1, 0≦b'≦0.2, 0≦c≦0.2; M comprises Mn and one or more selected from the group consisting of Ni, Co, Fe, Cr, V, Cu, Zn, and Ti; M' is one or more selected from the group consisting of Al, Mg, and B, and A is one or more selected from the group consisting of P, F, S, and N), and compounds substituted with one or more transition metals; 1+y Mn 2-y Lithium manganese oxides such as LiMnO4 (where y is 0-0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiFe3O4, V2O5, and Cu2V2O7; and the chemical formula LiNi 1-y Ni-site lithium nickel oxide represented by MyO2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and y=0.01-0.3); chemical formula: LiMn 2-y M y Examples of the lithium manganese composite oxides include, but are not limited to, lithium manganese composite oxides represented by LiMnO2 (where M=Co, Ni, Fe, Cr, Zn, or Ta, and y=0.01-0.1) or Li2Mn3MO8 (where M=Fe, Co, Ni, Cu, or Zn); LiMn2O4, in which part of the Li in the chemical formula is replaced with an alkaline earth metal ion; disulfide compounds; and Fe2(MoO4)3.

[0064] The positive electrode active material may be included in an amount of 40 to 80 wt % based on the total weight of the positive electrode active material layer. Specifically, the content of the positive electrode active material may be 40 wt % or more, or 50 wt % or more, or 70 wt % or less, or 80 wt % or less. If the content of the positive electrode active material is less than 40 wt %, the connectivity between the wet positive electrode active material layer and the dry positive electrode active material layer may be insufficient, and if it exceeds 80 wt %, the mass transfer resistance may be increased.

[0065] The binder is a component that aids in binding the positive electrode active material to the conductive material and the current collector, and may be selected from the group consisting of styrene-butadiene rubber, acrylated 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, polyvinyl acetate, polyepichlorohydrin, polyphosphagen, polyacrylic The binder may include at least one selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethyl cellulose, polystyrene, latex, acrylic resin, phenolic resin, epoxy resin, carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl cellulose, cyanoethyl sucrose, polyester, polyamide, polyether, polyimide, polycarboxylate, polycarboxylic acid, polyacrylic acid, polyacrylate, lithium polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyurethane, polyvinylidene fluoride, and poly(vinylidene fluoride)-hexafluoropropene. Preferably, the binder may include at least one selected from the group consisting of styrene-butadiene rubber, polytetrafluoroethylene, carboxymethyl cellulose, polyacrylic acid, lithium polyacrylate, and polyvinylidene fluoride.

[0066] The binder may be included in an amount of 1 wt% to 30 wt% based on the total weight of the positive electrode active material layer. Specifically, the binder content may be 1 wt% or more, or 3 wt% or more, or 15 wt% or less, or 30 wt% or less. If the binder content is less than 1 wt%, the adhesive strength between the positive electrode active material and the positive electrode current collector may be reduced. If the binder content exceeds 30 wt%, the adhesive strength is improved, but the content of the positive electrode active material may be reduced accordingly, resulting in a lower battery capacity.

[0067] 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 cause chemical changes in the battery, and has excellent electrical conductivity. Representative examples include graphite or conductive carbon. Examples include graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, denka black, thermal black, channel black, furnace black, lamp black, and thermal black; carbon-based materials having a graphene or graphite crystal structure; 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 alone or in combination. However, the conductive material is not necessarily limited thereto.

[0068] The conductive material may typically be included in an amount of 0.5 wt% to 30 wt% based on the total weight of the positive electrode active material layer. Specifically, the conductive material content may be 0.5 wt% or more, or 1 wt% or more, or 20 wt% or less, or 30 wt% or less. If the conductive material content is less than 0.5 wt%, the electrical conductivity improvement effect may be poor or the electrochemical characteristics of the battery may be degraded. If the conductive material content is too high, such as more than 30 wt%, the amount of positive electrode active material may be relatively reduced, resulting in reduced capacity and energy density. The method for incorporating the conductive material into the positive electrode is not particularly limited, and any conventional method known in the art, such as coating the positive electrode active material, may be used.

[0069] The positive electrode current collector supports the positive electrode active material layer and serves to transfer electrons between an external conductor and the positive electrode active material layer.

[0070] The positive electrode current collector is not particularly limited as long as it has high electronic conductivity and does not cause chemical changes in the all-solid-state battery, and examples of the positive electrode current collector include copper, stainless steel, aluminum, nickel, titanium, palladium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, silver, etc., and aluminum-cadmium alloys.

[0071] The positive electrode current collector may have a micro-irregular structure or a three-dimensional porous structure on its surface to strengthen the bonding strength with the positive electrode active material layer, and thus may include various forms such as a film, sheet, foil, mesh, net, porous body, foam, and nonwoven fabric.

[0072] The cathode can be fabricated by a conventional method. Specifically, the cathode active material, conductive material, and binder are mixed in an organic solvent to form a cathode active material layer. The resulting mixture is then coated on a cathode current collector, dried, and optionally compressed into a current collector to improve electrode density. Preferably, the organic solvent is one that can uniformly disperse the cathode active material, binder, and conductive material and is easily evaporated. Specific examples include acetonitrile, methanol, ethanol, tetrahydrofuran, water, and isopropyl alcohol.

[0073] In the present invention, the negative electrode includes a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector, the negative electrode active material layer including a negative electrode active material, a binder, and a conductive material.

[0074] The negative electrode active material is lithium (Li + The lithium ion-containing compound may include a material capable of reversibly intercalating or deintercalating lithium ions, a material capable of reacting with lithium ions to reversibly form a lithium-containing compound, lithium metal, or a lithium alloy.

[0075] The lithium ion (Li + The material capable of reversibly inserting or de-inserting lithium ions (Li) may be, for example, crystalline carbon, amorphous carbon, or a mixture thereof. + The material capable of reacting with lithium (Li) to reversibly form a lithium-containing compound may be, for example, tin oxide, titanium nitride, or silicone. 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).

[0076] Preferably, the negative electrode active material may be lithium metal, specifically, in the form of a lithium metal thin film or lithium metal powder.

[0077] The negative electrode active material may be included in an amount of 40 to 80 wt % based on the total weight of the negative electrode active material layer. Specifically, the content of the negative electrode active material may be 40 wt % or more, or 50 wt % or more, or 70 wt % or less, or 80 wt % or less. If the content of the negative electrode active material is less than 40 wt %, the connectivity between the wet negative electrode active material layer and the dry negative electrode active material layer may be insufficient, and if it exceeds 80 wt %, the mass transfer resistance may be increased.

[0078] The binder is the same as that described above for the positive electrode active material layer.

[0079] The conductive material is the same as that described above in the positive electrode active material layer.

[0080] The negative electrode current collector is not particularly limited as long as it is conductive and does not cause chemical changes in the battery, and examples of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. Similarly to the positive electrode current collector, the negative electrode current collector may be in various forms such as a film, sheet, foil, net, porous material, foam, nonwoven fabric, etc., having a finely textured surface.

[0081] The method for manufacturing the negative electrode is not particularly limited, and the negative electrode may be manufactured by forming a negative electrode active material layer on a negative electrode current collector using a layer or film formation method commonly used in the art, such as pressing, coating, deposition, etc. Furthermore, the negative electrode of the present invention also includes a case where a battery is assembled without a lithium thin film on the negative electrode current collector, and then a metallic lithium thin film is formed on the metal plate by initial charging.

[0082] The method for manufacturing the all-solid-state battery having the above-described structure is not particularly limited in the present invention, and known methods can be used.

[0083] When manufacturing the all-solid-state battery of the present invention, electrodes including a positive electrode and a negative electrode are arranged, and then the resulting structure is pressure-molded to assemble a cell.

[0084] The assembled cell is placed in an exterior material and then sealed by heating and squeezing, etc. As the exterior material, a laminate pack made of aluminum, stainless steel, etc., or a cylindrical or rectangular metal container is very suitable.

[0085] Preferred examples are presented below to aid in understanding the present invention. However, the following examples are merely illustrative of the present invention, and it will be obvious to those skilled in the art that various changes and modifications are possible within the scope of the scope and technical idea of ​​the present invention. It is natural that such changes and modifications also fall within the scope of the appended claims.

[0086] In the following Examples and Comparative Examples, solid electrolytes were prepared according to the types and weight ratios of the base material, polymer, lithium salt, and solvent as shown in Table 1 below.

[0087] [Table 1]

[0088] Example 1 The polymer polyethylene oxide (PEO, d1 = 1.125 g / cm 3 , Mw = 1,000,000 g / mol), and polymer particles, Polyether ether ketone (PEEK, d2 = 1.23 g / cm 3A mixed solution was prepared by mixing an ion-conducting polymer (Silvay) and a lithium salt, LiTFSI (Sigma Aldrich), with an organic solvent, NMP. The weight ratio of the polymer, polymer particles, and lithium salt was 72:20:8. The concentration of the mixed solution was 30%. The polymer particles had a particle size (d50) of 10 μm and a Young's modulus of 3.62 GPa. The density ratio (d2 / d1) of the density of the ion-conducting polymer (d1) to the density of the polymer particles (d2) was 1.09.

[0089] The mixed solution was bar coated on a polyethylene terephthalate (PET) release film as a substrate to form a coating layer.

[0090] Then, the coating layer was vacuum dried at 100° C. and separated from the substrate to prepare a polymer solid electrolyte.

[0091] Example 2 A polymer solid electrolyte was prepared in the same manner as in Example 1, except that the weight ratio of the ion-conductive polymer, polymer particles, and lithium salt was 63:30:7.

[0092] Example 3 Instead of PEEK, PPS (Solvay, d50 = 10 μm, d2 = 1.35 g / cm) was used as the polymer particles. 3 A polymer solid electrolyte and an all-solid-state battery were manufactured in the same manner as in Example 1, except that a pressure of 3800 MPa was used.

[0093] Comparative Example 1 A polymer solid electrolyte and an all-solid-state battery were produced in the same manner as in Example 1, except that polymer particles were not used.

[0094] Comparative Example 2 Instead of PEEK, ZnO (Sigma Aldrich, d = 5.61 g / cm) was used as the polymer particles. 3A polymer solid electrolyte and an all-solid-state battery were manufactured in the same manner as in Example 1, except that a polymer solid electrolyte having a thickness of 100 μm was used.

[0095] Comparative Example 3 Instead of PEEK, ZnO (Sigma Aldrich, d = 5.61 g / cm) was used as the polymer particle. 3 A polymer solid electrolyte and an all-solid-state battery were prepared using the same composition and method as in Example 2, except that a 0.1% SiO 2 , d50=5 μm was used.

[0096] Comparative Example 4 Instead of PEEK, LLZO (Lithium Lanthanum Zirconium oxide, d2 = 5.108 g / cm) was used as the polymer particle. 3 A polymer solid electrolyte and an all-solid-state battery were prepared using the same composition and method as in Example 1, except that ) was used.

[0097] Experimental Example 1: Evaluation of polymer solid electrolyte The solid polymer electrolytes prepared in the examples and comparative examples were tested for the density difference between the polymer and the polymer particles, the thickness of the solid polymer electrolyte, and the ionic conductivity, as described below, and the results are shown in Table 2 below.

[0098] (1) Ionic conductivity The solid polymer electrolyte sample was contacted with a lithium metal electrode of the same surface area, and an AC voltage was applied to both electrodes of the sample at room temperature. The impedance was measured using a BioLogic VMP3 with a measurement frequency ranging from 0.01 Hz to 1 MHz. The resistance of the solid polymer electrolyte was calculated from the intersection (Rb) of the semicircle or line of the measured impedance locus with the real axis, and the ionic conductivity of the solid polymer electrolyte was calculated from the area and thickness of the sample.

[0099] [Formula 1]

number

[0100] [Table 2]

[0101] As shown in Table 2, when PEO and polymer particles were used together instead of the PEO polymer alone as in Comparative Example 1, the crystallinity of PEO was reduced, facilitating ion transport at the interface and improving ionic conductivity. However, in Comparative Examples 2 to 4, where the density ratio was significantly different, ionic conductivity decreased due to aggregation, as in Comparative Example 3, where an excessive amount was added.

[0102] Although the present invention has been described above using limited examples and drawings, the present invention is not limited thereto, and it is of course possible for a person having ordinary skill in the art to which the present invention pertains to make various modifications and variations within the technical spirit of the present invention and the equivalent scope of the following claims. [Explanation of symbols]

[0103] 1: Polymer solid electrolyte 10: Polymer solid electrolyte matrix 11: Polymer chain 20: Polymer particles

Claims

1. an ion-conductive polymer, a lithium salt, and polymer particles; the density ratio (Δd) of the ion-conductive polymer to the polymer particles is 3 or less; the polymer particles are dispersed in an embedded state within a matrix of the ion-conductive polymer; The density ratio (Δd) is calculated by the following formula 1: <Formula 1> Δd=d2 / d1 In Equation 1, d1 is the density of the ion-conductive polymer, and d2 is the density of the polymer particles.

2. 2. The polymer solid electrolyte according to claim 1, wherein the density ratio (Δd) is 0.5 to 2.

5.

3. The polymer solid electrolyte according to claim 1, wherein the ion-conducting polymer comprises at least one selected from the group consisting of polyether-based polymers, polycarbonate-based polymers, acrylate-based polymers, polysiloxane-based polymers, phosphagen-based polymers, polyethylene derivatives, alkylene oxide derivatives, phosphate ester polymers, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionically dissociable groups, polypyrrole, polyaniline (PANI), and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS, Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)).

4. The lithium salt is Li ＋ X － is expressed as The anion (X of the lithium salt － ) is F － , Cl － , Br － , I － , NO ３ － , N(CN) ２ － , BF ４ － , ClO ４ － , PF ６ － , (CF ３ ) ２ PF ４ － , (CF ３ ) ３ PF ３ － , (CF ３ ) ４ PF ２ － , (CF ３ ) ５ PF － , (CF ３ ) ６ P － , CF ３ SO ３ － , CF ３ CF ２ SO ３ － , (CF ３ SO ２ ) ２ N － , (FSO ２ ) ２ N － , CF ３ CF ２ , (CF ３ ) ２ CO － , (CF ３ SO ２ ) ２ CH － , (SF ５ ) ３ C － , (CF ３ SO ２ ) ３ C － , CF ３ , (CF ２ ) ７ SO ３ － , C.F. ３ CO ２ － , C.H. ３ CO ２ － , SCN － or (CF ３ CF ２ SO ２ ) ２ N － The polymer solid electrolyte according to claim 1 ,

5. the polymer particles include an engineering plastic resin; The engineering plastic resins include polyphenylene sulfide (PPS), polyetheretherketone, polyimide, polyamideimide, liquid crystal polymer, polyetherimide, polysulfone, polyarylate, polyethylene terephthalate, polybutylene terephthalate, and the like.

2. The polymer solid electrolyte according to claim 1, comprising at least one selected from the group consisting of poly(ethylene terephthalate), polyoxymethylene, polycarbonate, polypropylene, polyethylene, and poly(methyl methacrylate).

6. The polymer solid electrolyte is 45 to 95% by weight of the ion-conductive polymer, 2 to 50% by weight of said lithium salt, and 2. The polymer solid electrolyte according to claim 1, wherein the polymer particles are contained in an amount of 2 to 35% by weight.

7. The particle diameter (d ５０ 2. The polymer solid electrolyte according to claim 1, wherein the average particle diameter is less than 20 μm.

8. The polymer solid electrolyte according to claim 1 , wherein the polymer solid electrolyte is in the form of a thin film having a thickness of 5 μm to 100 μm.

9. (S1) adding an ion-conductive polymer, a lithium salt, and polymer particles to an organic solvent to form a mixed solution; (S2) coating the mixed solution onto a substrate; and (S3) drying the coating layer formed on the substrate to form a polymer solid electrolyte; a density ratio (Δd) defined as the ratio of the densities of the ion-conductive polymer and the polymer particles is 3 or less; the polymer particles are dispersed in an embedded state within a matrix of the ion-conductive polymer; The density ratio (Δd) is calculated by the following formula 1: <Formula 1> Δd=d2 / d1 In Equation 1, d1 is the density of the ion-conductive polymer, and d2 is the density of the polymer particles.

10. 10. The method for producing a polymer solid electrolyte according to claim 9, wherein the organic solvent comprises at least one selected from the group consisting of alcohol-based solvents, glycol ether-based solvents, glycol ether ester-based solvents, ketone-based solvents, hydrocarbon-based solvents, lactic acid-based solvents, ester-based solvents, aprotic sulfoxide-based solvents, and nitrile-based solvents.

11. An all-solid-state battery comprising a positive electrode, a negative electrode, and the polymer solid electrolyte according to claim 1.

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