Composite solid polymer electrolyte having improved electrochemical stability window, method for preparing same, and solid polymer battery including same

Abstract

The present disclosure relates to a composite solid polymer electrolyte, a method for preparing same, and a solid polymer battery including same. The composite solid polymer electrolyte comprises: a polymer matrix; and a lithium salt and an ion conductor dispersed in the polymer matrix, wherein the ion conductor includes an inorganic oxide-based compound containing fluorine.

Description

Composite solid polymer electrolyte with improved electrochemical stability window, method for manufacturing the same, and solid polymer battery including the same

[0001] The present disclosure relates to a composite solid polymer electrolyte with an improved electrochemical stability window, a method for manufacturing the same, and a solid polymer battery comprising the same.

[0002] Research on solid-state batteries containing solid electrolytes is increasing to replace liquid electrolytes, which pose a high risk of fire and explosion due to various chemical reactions during operation. Unlike liquid electrolytes, solid electrolytes significantly improve battery stability and offer the advantage of reducing battery volume by eliminating the need for special sealing technologies to prevent leakage. Solid electrolytes can be broadly classified into inorganic solid electrolytes containing inorganic materials and solid polymer electrolytes containing organic polymer materials. Among these, solid polymer electrolytes possess excellent moldability, flexibility, and mechanical strength, as well as superior chemical and thermal stability.

[0003] Solid polymer electrolytes are electrolytes containing ion-conductive polymer materials; they have a low dielectric constant for lithium ions and high solvent capacity, but their ion conductivity at room temperature is 10 -8 It is low at the S / cm level. In addition, there is a problem of poor electrochemical stability because the electrochemical stability window (ESW), which is calculated as the difference between oxidation potential and reduction potential and refers to the voltage range in which a material is not oxidized or reduced, is very narrow at less than 4V. Consequently, there are limitations in improving the energy density of solid polymer batteries containing solid polymer electrolytes, and there are restrictions on their application to high-energy batteries.

[0004] To address this, various alternatives have been developed, such as forming a composite solid polymer electrolyte or a polymer electrolyte layer with a multilayer structure by combining organic and inorganic materials, or forming a protective layer or an interface layer on the surface adjacent to the electrode. However, there are limitations in expanding the electrochemical stability window, which restricts their use as high-energy batteries.

[0005] The purpose of the present disclosure is to solve the problems of the prior art described above by providing a composite solid polymer electrolyte capable of significantly improving the electrochemical stability of a battery in a high voltage range and thereby improving the energy density of the battery, a method for manufacturing the same, and a solid polymer battery including the same.

[0006] Another objective of the present disclosure is to provide a composite solid polymer electrolyte with excellent thermal stability that does not easily decompose even at high temperatures, a method for manufacturing the same, and a solid polymer battery comprising the same.

[0007] The composite solid polymer electrolyte of the present disclosure comprises a polymer matrix; and a lithium salt and an ion conductor dispersed within the polymer matrix; wherein the ion conductor comprises an inorganic oxide-based compound to which fluorine has been added.

[0008] In one example, the fluorine may be dispersed within the crystal of an inorganic oxide-based compound.

[0009] In one example, the inorganic oxide-based compound may be represented by the following chemical formula 1.

[0010] [Chemical Formula 1]

[0011] Li 1+x+y Al x Si y Ti 2-x P 3-y O 12 (0 <x<2, 0<y<3)

[0012] In one example, the inorganic oxide-based compound is Li 1.5 Al 0.3 Si0.2 Ti 1.7 P 2.8 O 12 It could be.

[0013] In one example, the ion conductor may contain 0.1 to 1.0 parts by weight of fluorine based on 100 parts by weight of an inorganic oxide-based compound.

[0014] In one example, the ion conductor may contain fluorine atoms in an amount of 0.1 to 1.5 atomic%.

[0015] In one example, the polymer matrix may contain a polyalkylene oxide-based polymer.

[0016] In one example, the polymer matrix may comprise a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer, at least one of the terminal functional groups being different from each other.

[0017] In one example, the first polyalkylene oxide-based polymer may contain at least one hydroxyl group (-OH) among the terminal functional groups, and the second polyalkylene oxide-based polymer may contain at least one alkoxy group (-OR) among the terminal functional groups.

[0018] In one example, the first polyalkylene oxide-based polymer may be one or more selected from the group comprising poly(methylene oxide, PMO), polyethylene oxide (Poly(ethylene oxide, PEO), and polypropylene oxide (Poly(propylene oxide, PPO).

[0019] In one example, the second polyalkylene oxide-based polymer may be one or more selected from the group comprising poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) diethyl ether, poly(ethylene glycol) dipropyl ether, poly(ethylene glycol) dibutyl ether, and poly(propylene glycol) dimethyl ether.

[0020] In one example, the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer may be a combination of polyethylene oxide (Poly(ethylene Oxide; PEO) and poly(ethyleneglycol) dimethyl ether (Poly(ethyleneglycol) dimethyl ether; PEGDME).

[0021] In one example, the polymer matrix may contain a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer in a weight ratio of 1:1.2 to 5.7.

[0022] In one example, the polymer matrix may have a semi-interpenetrating polymer network (SIPN) structure.

[0023] In one example, the ionic conductivity is 0.5 x 10 -4 Up to 5.0 x 10 -4 It can be S / cm.

[0024] In one example, when thermogravimetric analysis is performed at a heating rate of 10℃ / min at 25 to 500℃, the weight loss rate at 150 to 350℃ may be less than 18 weight%.

[0025] The present disclosure includes a method for manufacturing the aforementioned composite solid polymer electrolyte.

[0026] A method for manufacturing a composite solid polymer electrolyte according to the present disclosure comprises the steps of: preparing a composite solid polymer electrolyte composition by mixing an ion conductor comprising a lithium salt, a polymer, and an inorganic oxide-based compound to which fluorine has been added in a solvent; and drying the composite solid polymer electrolyte composition.

[0027] In one example, the ion conductor may be manufactured by a method comprising: (a) a step of preparing a calcined material by calcining a mixed powder containing an inorganic oxide-based compound powder and a fluorine powder; and (b) a step of preparing an ion conductor by sintering the calcined material.

[0028] In one example, the above step (a) may include: (a-1) a step of heating the mixed powder to a first temperature and calcining it first; and (a-2) a step of heating the mixed powder that has been calcined first to a second temperature and calcining it second to produce a calcined product.

[0029] In one example, the ratio (T2 / T1) of the first temperature (T1) and the second temperature (T2) may be 1.2 to 3.0.

[0030] In one example, the sintering of step (b) above may be performed at a temperature of 900 to 1300 ℃.

[0031] In one example, in the step of manufacturing the composite solid polymer electrolyte composition, an additive may be further added.

[0032] A solid polymer battery according to the present disclosure comprises the aforementioned composite solid polymer electrolyte.

[0033] In one example, the solid polymer battery may have an electrochemical stability window of 5.0 to 7.0 V with respect to lithium metal.

[0034] The composite solid polymer electrolyte of the present disclosure, the method for manufacturing the same, and the solid polymer battery including the same can significantly improve the electrochemical stability of the battery in a high voltage range, thereby improving the energy density of the battery.

[0035] In addition, it has the advantage of excellent thermal stability as it does not easily decompose even at high temperatures.

[0036] FIG. 1 is a schematic diagram illustrating the temperature change during calcination and sintering in the process of manufacturing an ion conductor according to one embodiment of the present disclosure.

[0037] FIG. 2 is a schematic diagram illustrating the configuration of a solid polymer battery according to one embodiment of the present disclosure.

[0038] Figure 3 is a scanning electron microscope image showing the surface structure of an ion conductor according to (a) Example 1, (b) Example 2, and (c) Example 3, respectively.

[0039] FIGS. 4 to 6 are drawings showing the energy dispersive spectroscopic analysis spectra and elemental composition of ion conductors according to Preparation Example 1, Preparation Example 2, and Preparation Example 3, respectively.

[0040] FIG. 7 is a scanning electron microscope image of the surface of the composite solid polymer electrolyte of (a) Comparative Example 4, (c) Example 2, (e) Comparative Example 5, and (g) Example 4, respectively, and a cross-sectional scanning electron microscope image of the composite solid polymer electrolyte of (b) Comparative Example 4, (d) Example 2, (f) Comparative Example 5, and (h) Example 4.

[0041] FIG. 8 is a graph showing the results of thermogravimetric analysis (TGA) of composite solid polymer electrolytes according to Examples 1 to 4, Comparative Example 1, and Comparative Example 2.

[0042] FIG. 9(a) is a graph measuring the cycle performance of solid polymer batteries according to Example 7 (■) and Example 8 (●), FIG. 9(b) and FIG. 9(c) are, respectively, a graph measuring (b) the rate capability of a solid polymer battery according to Example 8 and a charge-discharge curve according to (c) the change in charge-discharge rate (c-rate), and FIG. 9(d) is a charge-discharge curve of a solid polymer battery according to Example 11 under a voltage window of 2.5 to 4.7 V in an NCM811 half-cell battery.

[0043] FIG. 10 is a linear sweep voltammetry curve measuring the electrochemical stability window of a solid polymer battery according to (a) Comparative Example 6, (b) Example 7, and (c) Example 8, respectively.

[0044] The terms used in this specification have been selected to be as widely used as possible, taking into account the function of this disclosure; however, these terms may vary depending on the intent of those skilled in the relevant field, case law, the emergence of new technologies, etc. Unless otherwise defined, technical and scientific terms used may have the meaning commonly understood by those skilled in the art to which this invention pertains.

[0045] In this specification and the appended claims, terms such as "comprising" or "having" mean that the features or components described in the specification exist, and unless specifically limited, do not preclude the possibility that one or more other features or components may be added.

[0046] In this specification and the appended claims, terms such as "first," "second," etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another.

[0047] Singular expressions used in this specification and the appended claims include plural expressions unless the context clearly indicates that they are singular. Additionally, plural expressions include singular expressions unless the context clearly indicates that they are plural.

[0048] Additionally, numerical ranges used herein include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0049] Terms such as "approximately" used in this specification and the appended claims are used to encompass tolerances when tolerances exist.

[0050] The term 'high-energy battery' in this specification means a battery designed to operate at a high voltage level exceeding 4.2 V.

[0051] Hereinafter, the composite solid polymer electrolyte of the present disclosure, the method for manufacturing the same, and the solid polymer battery including the same will be described in detail.

[0052] A composite solid polymer electrolyte according to the present disclosure comprises a polymer matrix; and a lithium salt and an ion conductor dispersed within the polymer matrix; wherein the ion conductor comprises an inorganic oxide-based compound containing fluorine.

[0053] The composite solid polymer electrolyte of the present disclosure, in which an ion conductor containing a fluorine-containing inorganic oxide-based compound and a lithium salt are dispersed within a polymer matrix, has a higher electrochemical stability window, thereby significantly improving electrochemical stability and enabling improved battery energy density. Accordingly, particularly when used as an electrolyte for high-energy batteries, it has the advantage of enabling the operation of the battery with excellent cycle stability.

[0054] The above polymer matrix may contain a polyalkylene oxide-based polymer having excellent thermal stability, electrochemical stability, and ion conductivity, and more specifically, may contain two or more types of polyalkylene oxide-based polymers in which at least one of the terminal functional groups is different from each other.

[0055] In one embodiment, the polymer matrix may comprise a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer, wherein at least one of the terminal functional groups is different from each other. By including two types of polymers that are different from each other in the polymer matrix, electrochemical stability can be further improved while maintaining flexibility.

[0056] In a more specific and preferred example, the first polyalkylene oxide-based polymer may contain at least one hydroxyl group (-OH) among the terminal functional groups, and may include, for example, one or more selected from poly(methylene oxide, PMO), polyethylene oxide (Poly(ethylene oxide, PEO), and polypropylene oxide (Poly(propylene oxide, PPO), and preferably may include polyethylene oxide (Poly(ethylene oxide, PEO).

[0057] In addition, the second polyalkylene oxide-based polymer may contain at least one alkoxy group among the terminal functional groups, and may include, for example, one or more selected from the group comprising poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) diethyl ether, poly(ethylene glycol) dipropyl ether, poly(ethylene glycol) dibutyl ether, and poly(propylene glycol) dimethyl ether, and preferably may include poly(ethylene glycol) dimethyl ether.

[0058] The above-mentioned first polyalkylene oxide-based polymer has the advantages of high chemical stability, simple synthesis, and low manufacturing cost; however, it has low ionic conductivity at room temperature and may form a narrow electrochemical stability window due to the hydroxyl groups (-OH) located at the ends. Additionally, there is a concern that the long-term stability of the composite solid polymer electrolyte may be reduced due to decreased ionic conductivity at the interface with the electrode or the decomposition of the first polyalkylene oxide-based polymer.

[0059] Meanwhile, when the second polyalkylene oxide-based polymer is used alone as the matrix of the composite solid polymer electrolyte, it has the advantage of good flexibility, but its electrochemical stability is lower compared to the first polyalkylene oxide-based polymer, so it can easily decompose, especially in high-voltage environments, which can degrade battery performance.

[0060] However, when the aforementioned first polyalkylene oxide-based polymer and second polyalkylene oxide-based polymer are used in combination, the two different types of polymers are easily mixed while maintaining the characteristics of conventional polymer materials, such as flexibility and good processability, thereby enhancing ion conductivity, improving thermal stability by preventing the electrolyte from decomposing even at high temperatures, and widening the electrochemical stability window so that electrochemical stability and cycle performance can be significantly improved even under high voltage.

[0061] In one example, the polymer matrix may contain a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer in a weight ratio of 1:1.2 to 5.7, 1:1.5 to 4.0, 1:2.0 to 4.0, or 1:2.3 to 4.0. When the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer are contained in the above weight ratios, ionic conductivity can be significantly increased while simultaneously ensuring electrochemical stability.

[0062] The weight average molecular weight of the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer is not particularly limited in order to achieve the purpose of the present disclosure, but for example, the weight average molecular weight of the first polyalkylene oxide-based polymer may be 10,000 to 4,000,000 g / mol, 100,000 to 2,000,000 g / mol, or 600,000 to 1,000,000 g / mol, and preferably 100,000 to 700,000 g / mol.

[0063] In addition, the weight average molecular weight of the second polyalkylene oxide-based polymer may be smaller than the weight average molecular weight of the first polyalkylene oxide-based polymer. In one embodiment, the weight average molecular weight of the second polyalkylene oxide-based polymer may be 250 to 2,000 g / mol or 300 to 1,000 g / mol, and preferably 300 to 700 g / mol.

[0064] When the weight average molecular weight of the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer satisfies the above range, alkoxy groups are more abundant than hydroxyl groups within the polymer matrix, which can significantly improve electrochemical stability.

[0065] The polymer included in the above matrix may have a semi-interpenetrating polymer network (SIPN) structure. A semi-interpenetrating polymer network structure means that a linear first polyalkylene oxide-based polymer penetrates a network-structured second polyalkylene oxide-based polymer to form a cross-linked structure. Although the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer are physically mixed, they are intertwined in the cross-linked structure and thus cannot be easily separated. Accordingly, a composite solid polymer electrolyte with excellent mechanical strength, improved thermal and electrochemical stability, and excellent ionic conductivity can be realized.

[0066] The ion conductor is uniformly dispersed within the polymer matrix, thereby improving the ion conductivity of the electrolyte and enhancing battery stability and performance while minimizing the increase in battery volume. During battery operation, lithium ions can be intercalated and deintercalated more stably, and long-term stability can be improved by enhancing the interfacial affinity between the electrode and the electrolyte.

[0067] More specifically, by including a fluorine-containing inorganic oxide-based compound in the ion conductor, oxidation stability under high voltage can be improved, and compatibility between the electrolyte and the electrode active material can be enhanced.

[0068] The fluorine mentioned above may be dispersed within the crystals of an inorganic oxide-based compound. The dispersion of fluorine within the inorganic oxide-based compound can enhance electrolyte stability. Furthermore, the highly dispersed fluorine within the inorganic oxide-based compound may form physical or chemical bonds with the inorganic oxide-based compound. While not strictly limited to this interpretation, it may be advantageous for the fluorine to form physical bonds with the inorganic oxide-based compound in order to further improve battery stability and performance by allowing fluorine atoms to migrate to the negative electrode surface during battery operation to form a high-quality Solid Electrolyte Interface (SEI).

[0069] In one embodiment, the ion conductor may contain fluorine in an amount of 0.01 to 10 parts by weight, 0.05 to 5.0 parts by weight, 0.1 to 1.0 parts by weight, 0.2 to 0.9 parts by weight, 0.3 to 0.8 parts by weight, or 0.4 to 0.7 parts by weight, based on 100 parts by weight of an inorganic oxide-based compound.

[0070] In addition, the ion conductor may contain fluorine atoms in an amount of 0.01 to 5.0 atomic%, 0.05 to 3.0 atomic%, 0.1 to 1.5 atomic%, 0.3 to 1.0 atomic%, or 0.5 to 0.9 atomic%. Within the above range, fluorine may be uniformly dispersed within the inorganic oxide-based compound.

[0071] The above inorganic oxide-based compound can be represented by the following chemical formula 1.

[0072] [Chemical Formula 1]

[0073] Li 1+x+y Al x Si y Ti 2-x P 3-y O 12 (0 <x<2, 0<y<3)

[0074] In one embodiment, the inorganic oxide-based compound is Li 1.5 Al 0.3 Si 0.2 Ti 1.7 P 2.8 O 12 It is possible. As a fluorine-containing inorganic oxide-based compound having the above composition is dispersed within the aforementioned polymer matrix, a synergistic effect occurs due to the combination of the polymer matrix and the lithium salt, thereby effectively improving thermal stability, electrochemical stability, and ion conductivity.

[0075] In one example, the lithium salt may be any lithium salt used in the electrolyte of a conventional lithium-ion battery, and examples include LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10 Lithium salts selected from the group consisting of LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, LiTFSi (Lithium bis(trifluoromethanesulfonyl)imide), lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, and combinations thereof may be included, preferably LiTFSi, but the present disclosure is not limited thereto.

[0076] In one example, the composite solid polymer electrolyte may further include additives for the purpose of improving charge / discharge characteristics or flame retardancy. For instance, one or more additives selected from the group comprising pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphate triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, and aluminum trichloride may be used. In some cases, to impart non-flammability, a halogen-containing solvent such as carbon tetrachloride or trifluoroethylene may be further included, and to improve high-temperature storage characteristics, carbon dioxide gas may be further included, and FEC (Fluoro-Ethylene Carbonate), PRS (Propanesultone), etc. may be further included.

[0077] In one example, the above-described composite solid polymer electrolyte has an ionic conductivity of 0.5 x 10 -4 Up to 5.0 x 10 -4 It can be significantly improved by S / cm.

[0078] In one example, when thermogravimetric analysis is performed at 25 to 500 ℃ at a heating rate of 10 ℃ / min, the weight loss rate at 150 to 350 ℃ or 200 to 300 ℃, specifically at 250 ℃, may be less than 18.0 wt%, less than 17.0 wt%, or less than 16.5 wt%, and advantageously may be less than 5 wt%, less than 4 wt%, or less than 3 wt%. A composite solid polymer electrolyte having a weight loss rate within the above range can minimize decomposition at high temperatures, thereby significantly improving thermal stability.

[0079] The present disclosure includes a method for manufacturing the composite solid polymer electrolyte described above and a solid polymer battery comprising the composite solid polymer electrolyte. Prior to describing the method for manufacturing the composite solid polymer electrolyte and the solid polymer battery of the present disclosure, the material, structure, shape, or size, etc., of the polymer matrix, lithium salt, ion conductor, and additive included in the composite solid polymer electrolyte are identical or similar to those described above; therefore, the method for manufacturing the composite solid polymer electrolyte and the solid polymer battery according to the present disclosure include all the contents described above regarding the composite solid polymer electrolyte.

[0080] A method for manufacturing a composite solid polymer electrolyte according to the present disclosure comprises the steps of: mixing a lithium salt; a polymer; and an ion conductor comprising an inorganic oxide-based compound to which fluorine has been added in a solvent to prepare a composite solid polymer electrolyte composition; and drying the composite solid polymer electrolyte composition.

[0081] A composite solid polymer electrolyte with high ionic conductivity, thermal stability, and electrochemical stability can be realized by a simple method of mixing a lithium salt, a polymer, and an ion conductor with a solvent, followed by drying and solidifying.

[0082] The above ion conductor may be manufactured by a method comprising: (a) a step of preparing a calcined material by calcining a mixed powder containing an inorganic oxide-based compound precursor powder and a fluorine powder; and (b) a step of preparing an ion conductor by sintering the calcined material.

[0083] In one example, in step (a) above, the mixed powder may be added in an amount of 0.1 to 20 parts by weight, 0.5 to 17 parts by weight, or 1 to 15 parts by weight based on 100 parts by weight of the inorganic oxide-based compound precursor powder, and preferably 5 to 10 parts by weight of fluorine powder may be added. When fluorine powder is added in the above amounts, fluorine is not volatilized during calcination and sintering and is uniformly dispersed within the inorganic oxide-based compound, thereby significantly improving electrochemical performance.

[0084] By multi-stage heating during the calcination of step (a) above, a uniform reaction can be induced while preventing the volatilization of inorganic oxide compounds and fluorine.

[0085] Specifically, the above step (a) may include: (a-1) a step of heating the mixed powder to a first temperature and calcining it first; and (a-2) a step of heating the mixed powder that has been calcined first to a second temperature and calcining it second to produce a calcined product.

[0086] (a-1) By performing primary calcination at a low temperature, the synthesis of an ion conductor in which fluorine is uniformly dispersed within an inorganic oxide-based compound can be induced while preventing the volatilization of the inorganic oxide-based compound precursor powder and the fluorine powder.

[0087] Subsequently, in step (a-2), a homogeneous ion conductor can be produced by crystallizing fluorine-containing inorganic oxide particles by secondary calcination at a temperature higher than the first temperature.

[0088] More specifically, the first temperature is lower than the second temperature, and the ratio (T2 / T1) of the first temperature (T1) and the second temperature (T2) may be 1.2 to 3.0, 1.3 to 2.7, 1.4 to 2.4, or 1.5 to 2.0. Within the above range, the volatilization of each component can be minimized to produce a high-quality ion conductor having a desired composition ratio.

[0089] Subsequently, an ion conductor can be manufactured by sintering the calcined material in step (b). The sintering in step (b) can be performed at a temperature of 900 to 1300 ℃, 950 to 1200 ℃, or 1000 to 1100 ℃. When sintering within the above range, an ion conductor with improved density can be manufactured by increasing the particle size of the ion conductor while minimizing changes in the physical properties of the ion conductor.

[0090] In one example, the above calcined material can be pelletized and then sintered at a high temperature to induce more uniform sintering.

[0091] In a specific example, the step of preparing the composite solid polymer electrolyte composition may include: a step of preparing a mixed solution in which a lithium salt and a polymer are dissolved in a solvent; and a step of preparing the composite solid polymer electrolyte composition by adding an ion conductor powder to the mixed solution and heating it.

[0092] More specifically, when two types of polymers are introduced, the step of preparing the composite solid polymer electrolyte composition may include: a step of preparing a first mixed solution by dissolving a lithium salt and a first polyalkylene oxide-based polymer in a solvent; a step of preparing a second mixed solution by mixing a second polyalkylene oxide-based polymer into the first mixed solution; and a step of preparing a composite solid polymer electrolyte composition by introducing an ion conductor into the second mixed solution and heating it.

[0093] When the first polyalkylene oxide-based polymer, the second polyalkylene oxide-based polymer, and the ion conductor are introduced in the above order, the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer can form a semi-interpenetrating polymer network (SIPN), and a composite solid polymer electrolyte composition in which the ion conductor and the lithium salt are uniformly dispersed within the polymer matrix can be prepared due to excellent miscibility.

[0094] In one example, when two different types of polymers are introduced as the polymer, the composition may include a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer, wherein the first polyalkylene oxide-based polymer and the second polyalkylene oxide-based polymer may be introduced in a weight ratio of the first polyalkylene oxide-based polymer to the second polyalkylene oxide-based polymer of 1:1.2 to 5.7, 1:1.5 to 4.0, 1:2.0 to 4.0, or 1:2.3 to 4.0. When mixed in the above weight ratio, the viscosity of the composite solid polymer electrolyte composition does not rise excessively, thereby improving workability.

[0095] In one example, an additive may be further added during the step of manufacturing the composite solid polymer electrolyte composition. Specifically, the performance of the battery can be further improved by adding the additive when introducing the ion conductor.

[0096] In one example, during the step of preparing a composite solid polymer electrolyte composition, the components can be mixed more uniformly by stirring at 1,000 to 3,000 rpm, 1,300 to 2,700 rpm, 1,600 to 2,400 rpm, or 1,800 to 2,200 rpm. Additionally, the composite solid polymer electrolyte composition can be prepared by heating to a temperature of 30 to 80°C, 35 to 70°C, or 40 to 60°C. Within the above range, a composite solid polymer electrolyte composition in which an ion conductor and a lithium salt are uniformly dispersed within a polymer matrix can be prepared.

[0097] The above solvent is not particularly limited as long as it is non-reactive with respect to the polymer, lithium salt, and ion conductor and can disperse them well, and examples include ethylene carbonate (EC), propylene carbonate (PC), 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 (γGBL), acetonitrile (ACN), and It may be one or more selected from the group including sulfolane. When considering the combination with the polymer, lithium salt, and ion conductor, it is preferable to include acetonitrile (ACN) as the solvent, but the present disclosure is not limited by the type of solvent.

[0098] A composite solid polymer electrolyte can be prepared by removing the solvent through a drying step using the manufactured composite solid polymer electrolyte composition. According to a more specific embodiment, when manufacturing a battery, the composite solid polymer electrolyte composition may be applied to at least one of the negative electrode and the positive electrode, and then a drying step may be performed.

[0099] The above drying may be performed at a temperature higher than the boiling point of the solvent so that the solvent can be selectively volatilized, and as a specific example, it may be performed for 1 to 5 hours or 2 to 4 hours under temperature conditions of 50 to 200°C or 60 to 150°C, but the present disclosure is not limited thereto.

[0100] In one embodiment, a heat treatment step may be further performed after the drying step to produce a solidified composite solid polymer electrolyte. The heat treatment step may be performed at 50 to 200°C, 60 to 150°C, or 70 to 100°C for 6 to 24 hours, 8 to 20 hours, or 10 to 16 hours after assembling a first electrode containing the composite solid electrolyte and a second electrode spaced apart from it to form an electrode assembly, but the present disclosure is not limited thereto.

[0101] A solid polymer battery according to the present disclosure comprises the composite solid polymer electrolyte described above. Specifically, the solid polymer battery may comprise a negative electrode; a positive electrode spaced apart from a surface facing the negative electrode; and a composite solid polymer electrolyte disposed between the negative electrode and the positive electrode.

[0102] As described above, a solid polymer battery containing a composite solid polymer electrolyte according to the present disclosure has high ionic conductivity and improved thermal stability, and can also be operated stably with high energy density due to a wide electrochemical stability window.

[0103] In one embodiment, the solid polymer battery may have a high electrochemical stability window of 5.0 to 7.0 V, 5.1 to 6.9 V, 5.2 to 6.8 V, or 5.3 V to 6.7 V with respect to lithium metal.

[0104] The above-mentioned anode may be a conventional anode known in the art. For example, the anode may have an anode material comprising an anode active material, a conductive material, and a binder positioned on an anode current collector.

[0105] The above current collector is a highly conductive metal to which the slurry of the positive electrode active material can easily adhere. It is not particularly limited as long as it has high conductivity without causing chemical changes in the battery within the voltage range of the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treated with carbon, nickel, titanium, silver, etc., may be used. Additionally, fine irregularities may be formed on the surface of the current collector to increase the adhesion of the positive electrode active material. The current collector can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics, and its thickness can be adjusted according to the application.

[0106] The above positive active material is lithium cobalt oxide [Li x CoO2(0.5 <x<1.3)], 리튬 니켈 산화물[Li x NiO2(0.5 <x<1.3)] 등의 층상 화합물 또는 추가적인 전이금속으로 치환된 화합물; 화학식 Li 1+x Mn 2-x O4(0≤x≤0.33), LiMnO3, LiMn2O3, or [Li x MnO2(0.5 <x<1.3)] 등의 리튬 망간 산화물; 리튬 구리 산화물(Li2CuO2); LiV3O8, LiFe3O4, V2O5, 또는 Cu2V2O7등의 바나듐 산화물; 화학식 LiNi 1-x M x Ni-site type lithium nickel oxide represented by O2 (where M=Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x=0.01 to 0.3); chemical formula LiMn 2-x M xIt may be a lithium manganese complex oxide represented by O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which a portion of the Li in the chemical formula is substituted with alkaline earth metal ions; disulfide compounds; Fe2(MoO4)3, etc. Lithium cobalt oxide substituted with the additional transition metal [Li x CoO2(0.5 <x<1.3)] 또는 리튬 니켈 산화물[Li x NiO2(0.5 <x<1.3)] 등의 층상 화합물로는 리튬 니켈-망간-코발트 산화물을 들 수 있다.

[0107] The above binders include polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidenefluoride (PVDF), polyacrylonitrile (PAN), polymethylmethacrylate (PMMA), polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone (PVP), tetrafluoroethylene (TFE), polyethylene (PE), polypropylene (PP), polyacrylic acid (PAA), ethylene-propylene-dien monomer (EPDM), sulfonated EPDM, and styrene butadiene rubber (styrene Various types of binders, such as butadiene rubber (SBR), fluororubber, polymers in which the hydrogens thereof are substituted with Li, Na, or Ca, or various copolymers, can be used without limitation.

[0108] The above conductive material is not particularly limited as long as it is conductive without causing chemical changes in the battery, and examples may be used such as graphite, such as natural graphite or artificial graphite; carbon black, such as acetylene black, Ketjen black, channel black, Farnes black, lamp black, thermal black; conductive fibers, such as carbon fibers or metal fibers; conductive tubes, such as carbon nanotubes; metal powders, such as fluorocarbon, aluminum, or nickel powder; conductive whiskers, such as zinc oxide or potassium titanate; conductive metal oxides, such as titanium oxide; and conductive materials, such as polyphenylene derivatives.

[0109] The cathode can also be a conventional cathode known in the art, and, for example, a cathode material comprising a cathode active material, a conductive material, and a binder may be positioned on a cathode current collector.

[0110] The above-mentioned cathode active material can typically be a carbon material, lithium metal, silicon, or tin, which can absorb and release lithium ions. Preferably, a carbon material can be used, and the carbon material can be either low-crystallinity carbon or high-crystallinity carbon. Representative examples of low-crystallinity carbon include soft carbon and hard carbon, while representative examples of high-crystallinity carbon include natural graphite, kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch-derived cokes.

[0111] The negative electrode current collector is generally made with a thickness of 3 μm to 500 μm. Such a negative electrode current collector is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloys may be used. In addition, similar to the positive electrode current collector, fine irregularities may be formed on the surface to strengthen the bonding strength of the negative electrode active material, and it may be used in various forms such as films, sheets, foils, nets, porous materials, foams, and nonwoven materials.

[0112] The binder and conductive material used in the above cathode may be those commonly used in the field, just like the anode.

[0113] In a non-limiting example, a separator interposed between the anode and the cathode may be further included. The separator may be an insulating thin film having high ion permeability and mechanical strength. Exemplarily, one or more polyolefin-based separators selected from polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), and polyethersulfone (PES); cellulose-based separators; glass fibers; ceramics; or metal separators may be included, but the present disclosure is not limited by specific types of separators.

[0114] The present invention will be explained in more detail below through examples.

[0115] (Preparation Example 1) Preparation of ion conductor (0wt% F-LASTP)

[0116] To prepare an ion conductor, powdered lithium chloride (Mw: 42.39, >99%, Sigma-Aldrich), aluminum nitrate hydrate (Mw: 375.12 g, >98%, Sigma-Aldrich), tetraethoxysilane (Mw: 208.329 g, 98%, Sigma-Aldrich), titanium(IV) n-butoxide (Mw: 340.327 g, >99%, Sigma-Aldrich), and ammonium phosphate base (Mw: 115.025 g, >98%, Sigma-Aldrich) were used as inorganic oxide-based compound precursors.

[0117] The above inorganic oxide-based compound precursor powder was quantified according to the composition of the inorganic oxide ion conductor and fed into a mixer, and a mixed powder was prepared by repeating the process at 2000 rpm for 20 minutes at least 3 times.

[0118] Subsequently, as shown in Fig. 1, the mixed powder was subjected to primary calcination by heating from room temperature to 400°C over 2 hours and maintaining the temperature for 5 hours. Next, the temperature was raised from 400°C to 750°C over 2 hours and maintained for 10 hours, after which it was returned to room temperature. The calcined material was mixed in a mortar and formed into pellets with a diameter of 19 mm and a thickness of approximately 3 to 4 mm. The pellets were sintered by heating from room temperature to 1050°C over 3 hours and maintaining the temperature for 24 hours; the pellets were then naturally cooled to room temperature and ground to form Li 1.5 Al 0.3 Si 0.2 Ti 1.7 P 2.8 O 12 An ion conductor having the composition was prepared. It was named 0wt% F-LASTP.

[0119] (Preparation Example 2) Preparation of ion conductor (5wt% F-LASTP)

[0120] An ion conductor was prepared in the same manner as in Preparation Example 1, except that ammonium fluoride (Mw: 91.007 g, >98.0%, Sigma-Aldrich) was added during the preparation of the mixed powder. At this time, an inorganic oxide-based compound precursor powder and ammonium fluoride were added and mixed in a weight ratio of 95:5. This was named 5wt% F-LASTP.

[0121] (Preparation Example 3) Preparation of ion conductor (10 wt% F-LASTP)

[0122] An ion conductor was prepared in the same manner as in Preparation Example 2, except that when preparing the mixed powder, an inorganic oxide-based compound precursor powder and ammonium fluoride were added and mixed in a weight ratio of 90:10. This was named 10wt% F-LASTP.

[0123] (Preparation Example 4) Preparation of P2PE8

[0124] Polyethylene oxide (average molecular weight (Mw): 600,000, 98-99%, Sigma-Aldrich) and LiTFSI (99.95%) powders were each placed in a vacuum oven and dried at 100°C for at least 12 hours. Poly(ethylene glycol)dimethyl ether (average molecular weight (Mw): 500, 99%, Sigma-Aldrich) was distilled in a dry room for about one month under conditions of 50°C and 200 rpm until the moisture content was 10 ppm or less. The distilled poly(ethylene glycol)dimethyl ether (hereinafter referred to as PEGDME) was stored in a glove box with a moisture content of 0.1 ppm or less along with molecular sieve 4A (4-12 mesh). Additionally, the prepared polyethylene oxide (hereinafter referred to as PEO), LiTFSI, and other reagents were stored in a glove box with a moisture content of less than 0.1 ppm for use.

[0125] LiTFSI was dissolved in acetonitrile, followed by the addition of PEO and stirring until completely dissolved to prepare a first mixed solution. PEGDME was added to the first mixed solution and heated to 50°C while stirring to prepare a second mixed solution. At this time, PEO and PEGDME were added in a weight ratio of 20:80, and the second mixed solution contained 1 wt% LiTFSI, 1.8 wt% PEO, 19.8 wt% PEGDME, and 77.4 wt% solvent. Immediately before assembling the battery cell, fluoroethylene carbonate (FEC) was added to the second mixed solution to prepare a composite solid polymer electrolyte composition. At this time, 5 wt% of FEC was added based on 100 wt% of a polymer matrix containing PEO and PEGDME. This was named P2PE8.

[0126] (Preparation Example 5) Preparation of P3PE7

[0127] The procedure was carried out in the same manner as Preparation Example 4, except that PEO and PEGDME were added in a weight ratio of 30:70. This was named P3PE7.

[0128] (Preparation Example 6) Preparation of P4PE6

[0129] The procedure was carried out in the same manner as Preparation Example 4, except that PEO and PEGDME were added in a weight ratio of 40:60. This was named P4PE6.

[0130] (Preparation Example 7) Preparation of P2PE8-0 wt% F-LASTP

[0131] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 4, but adding 5 parts by weight of the ion conductor of Preparation Example 1 to the second mixed solution based on 100 parts by weight of the polymer matrix. This was named P2PE8-0 wt% F-LASTP.

[0132] (Preparation Example 8) Preparation of P2PE8-5 wt% F-LASTP

[0133] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 7, except that the ion conductor of Preparation Example 2 was added. This was named P2PE8-5 wt% F-LASTP.

[0134] (Preparation Example 9) Preparation of P2PE8-10 wt% F-LASTP

[0135] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 7, except that the ion conductor of Preparation Example 3 was added. This was named P2PE8-10 wt% F-LASTP.

[0136] (Preparation Example 10) Preparation of P3PE7-0 wt% F-LASTP

[0137] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 5, but adding 5 parts by weight of the ion conductor of Preparation Example 1 to the second mixed solution based on 100 parts by weight of the polymer matrix. This was named P3PE7-0 wt% F-LASTP.

[0138] (Preparation Example 11) Preparation of P3PE7-5 wt% F-LASTP

[0139] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 10, except that the ion conductor of Preparation Example 2 was added. This was named P3PE7-5 wt% F-LASTP.

[0140] (Preparation Example 12) Preparation of P3PE7-10 wt% F-LASTP

[0141] A composite solid polymer electrolyte composition was prepared by performing the same procedure as in Preparation Example 10, except that the ion conductor of Preparation Example 3 was added. This was named P3PE7-10 wt% F-LASTP.

[0142] (Examples 1 to 4 and Comparative Examples 1 to 5)

[0143] One composite solid polymer electrolyte composition selected from Preparation Examples 4 to 12 was cast onto the surface of one of two stainless steel (SS) blocking electrodes, dried at 25°C for at least 3 hours in a glove box filled with Ar, and a 2032 type coin cell was assembled. Subsequently, the assembled 2032 type coin cell was heat-treated at 80°C for 12 hours in an atmospheric pressure electric furnace to produce a solid polymer coin cell. The types of composite solid polymer electrolyte compositions used are shown in Table 1 below.

[0144] Composite Solid Polymer Electrolyte Composition Type Cathode Anode Example 1 Preparation Example 8 (P2PE8-5 wt% F-LASTP)SSSS Example 2 Preparation Example 9 (P2PE8-10 wt% F-LASTP)SSSS Example 3 Preparation Example 11 (P3PE7-5 wt% F-LASTP)SSSS Example 4 Preparation Example 12 (P3PE7-10 wt% F-LASTP)SSSS Comparative Example 1 Preparation Example 4 (P2PE8)SSSS Comparative Example 2 Preparation Example 5 (P3PE7)SSSS Comparative Example 3 Preparation Example 6 (P4PE6)SSSS Comparative Example 4 Preparation Example 7 (P2PE8-0 wt% F-LASTP)SSSS Comparative Example 5 Preparation Example 10 (P3PE7-0 wt% F-LASTP)SSSS

[0145] (Examples 5 to 8 and Comparative Examples 6 to 10)

[0146] As shown in Fig. 2, a solid polymer battery was manufactured. Lithium metal was used as the negative electrode, and the positive electrode was manufactured by applying a positive electrode slurry containing a positive electrode active material, a binder, and a conductive material onto an Al current collector and then drying it. The positive electrode slurry was prepared by adding 70 wt% lithium iron phosphate (LFP), 6.13 wt% PVDF, 3.63 wt% LiTFSI, 12.26 wt% PEGDME, and 8 wt% Super P to an N-methylpyrrolidone solvent and mixing them using a mixer (Thinky Cop., ARE-310). The manufactured positive electrode slurry was applied to an Al current collector to a thickness of 150 μm, dried in an electric furnace at 80°C for more than 2 hours, and then dried in a vacuum electric furnace at 100°C for 12 hours.

[0147] One composite solid polymer electrolyte composition selected from Preparation Examples 4 to 12 was cast into either the anode or the cathode above, dried at 25°C for at least 3 hours in a glove box filled with Ar, and then assembled into a 2032 type coin cell. Subsequently, the assembled 2032 type coin cell was heat-treated at 80°C for 12 hours in an atmospheric pressure electric furnace to manufacture a solid polymer battery. The types of composite solid polymer electrolyte compositions used are shown in Table 2 below.

[0148] Composite Solid Polymer Electrolyte Composition Type Cathode Anode Example 5 Preparation Example 8 (P2PE8-5 wt% F-LASTP)Li metal LFP Example 6 Preparation Example 9 (P2PE8-10 wt% F-LASTP)Li metal LFP Example 7 Preparation Example 11 (P3PE7-5 wt% F-LASTP)Li metal LFP Example 8 Preparation Example 12 (P3PE7-10 wt% F-LASTP)Li metal LFP Comparative Example 6 Preparation Example 4 (P2PE8)Li metal LFP Comparative Example 7 Preparation Example 5 (P3PE7)Li metal LFP Comparative Example 8 Preparation Example 6 (P4PE6)Li metal LFP Comparative Example 9 Preparation Example 7 (P2PE8-0 wt% F-LASTP)Li metal LFP Comparative Example 10 Preparation Example 10 (P3PE7-0 wt% F-LASTP)Li metalLFP

[0149] (Examples 9, 10 and Comparative Examples 11 to 13)

[0150] A solid polymer battery was prepared by performing the same procedure as in Example 7, Example 8, Comparative Example 6, Comparative Example 7, and Comparative Example 10, respectively, except that a stainless steel electrode was used as the anode. The types of composite solid polymer electrolyte compositions used are shown in Table 3 below.

[0151] Composite Solid Polymer Electrolyte Composition Type Cathode Anode Example 9 Preparation Example 11 (P3PE7-5 wt% F-LASTP)Li metal SS Example 10 Preparation Example 12 (P3PE7-10 wt% F-LASTP)Li metal SS Comparative Example 11 Preparation Example 4 (P2PE8)Li metal SS Comparative Example 12 Preparation Example 5 (P3PE7)Li metal SS Comparative Example 13 Preparation Example 10 (P3PE7-0 wt% F-LASTP)Li metal SS

[0152] (Example 11)

[0153] A solid polymer battery was prepared in the same manner as in Example 8, except that NMC622 was used instead of lithium iron phosphate (LFP) as the positive electrode active material.

[0154] Physical Property Evaluation Methods

[0155] Scanning electron microscope: The surface and cross-sectional structure of the composite solid polymer electrolyte was observed using a scanning electron microscope (Hitachi, Su 70).

[0156] Thermogravimetric analysis (TGA): Using a thermogravimetric analyzer (SDTQ600 V20.9 Build 20, TA Instruments), the weight loss rate was observed while heating the sample from room temperature to 500°C at a rate of 10°C under a nitrogen flow.

[0157] Ion conductivity: Ion conductivity was measured using a WMPG 1000 impedance analyzer (WonATech), and the AC impedance spectrum was measured using a sine wave with an amplitude of 10 mV in the frequency range of 20 MHz to 100 mHz. For impedance measurement, a 2030-type coin cell using stainless steel as the blocking electrode was used for the cathode and anode, and the ion conductivity was calculated according to Equation 1 below.

[0158] [Equation 1]

[0159]

[0160] (In Equation 1 above, σ is ionic conductivity, l is electrolyte thickness, A is electrolyte area, and R b represents bulk resistance)

[0161] Electrochemical performance: Measured using a multichannel potentiostatic / galvanostatic analyzer (Toyo, Toscat-3000).

[0162] (Evaluation Example 1) Surface structure and composition analysis

[0163] The surface structures of the ion conductors according to Preparation Examples 1 to 3 were observed using a scanning electron microscope and are shown in Fig. 3 below. Unlike Preparation Example 1, in which no fluorine was added during the preparation of the ion conductor, the ion conductors of Preparation Example 2, prepared by adding 5 wt% fluorine, and Preparation Example 3, prepared by adding 10 wt% fluorine, showed that fluorine was mixed with the inorganic oxide-based compound and introduced into the crystal structure of the inorganic oxide-based compound.

[0164] In addition, the elemental composition of the ion conductor was analyzed using an energy dispersive spectrometer (EDAX, TEAM EDS system) attached to a scanning electron microscope and is shown in Figures 4 to 6 below (EDS measurement conditions: 15 kV, Mag: 300, Takeoff: 30, Live time: 50 s, Amp Time: 7.68 μs, Resolution: 132.4 eV).

[0165] FIGS. 4 to 6 illustrate the EDS analysis spectra and elemental composition of the ion conductors of Preparation Examples 1 to 3, respectively. In the case of Preparation Example 1, in which no fluorine was added during the preparation of the ion conductor, it did not contain fluorine. However, the ion conductors of Preparation Examples 2 and 3, in which fluorine was added at 5 wt% and 10 wt%, respectively, during the preparation of the ion conductor, contained fluorine at 0.55 wt% and 0.67 wt%, respectively, and atomic percentages of 0.72 atomic% and 0.87 atomic%, respectively. This indicates that the fluorine did not volatilize during the preparation of the ion conductor and was combined with the inorganic oxide-based compound.

[0166] The solid polymer batteries of Example 2, Example 4, Comparative Example 4, and Comparative Example 5 were disassembled, and the surface and cross-section of the composite solid polymer electrolyte were observed using a scanning electron microscope and are shown in Fig. 7 below.

[0167] Referring to FIG. 7, it was confirmed that compared to the composite solid polymer electrolytes of Comparative Examples 4 and 5 containing ion conductors without added fluorine, the surface pore size of the composite solid polymer electrolytes of Examples 2 and 4 containing ion conductors with added fluorine was reduced, the pore density was increased, and the electrolyte thickness was increased. In particular, it was found that the composite solid polymer electrolyte of Example 4, in which PEO and PEGDME were mixed in a weight ratio of 30:70, formed the most uniform thickness, indicating that a high-quality composite solid polymer electrolyte was formed.

[0168] (Evaluation Example 2) Ionic Conductivity Evaluation

[0169] Impedance analysis of solid polymer batteries according to the above Examples 3, 4, Comparative Example 1, Comparative Example 2, and Comparative Example 5 was performed, and ionic conductivity was calculated according to Equation 1 and shown in Table 4 below.

[0170] Type of Composite Solid Polymer Electrolyte Composition Ionic Conductivity (S / cm) Comparative Example 1 Preparation Example 4 (P2PE8) 8.5 x 10 -5 Comparative Example 2 Manufacturing Example 5 (P3PE7) 1.2 x 10 -4 Comparative Example 5 Manufacturing Example 10 (P3PE7-0 wt.% F-LASTP) 1.8 x 10 -4 Example 3 Preparation Example 11 (P3PE7-5 wt.% F-LASTP) 2.4 x 10 -4 Example 4 Preparation Example 12 (P3PE7-10 wt.% F-LASTP) 4.8 x 10 -4

[0171] Referring to Table 4, the solid polymer batteries of Examples 3 and 4 using composite solid polymer electrolytes containing fluorine-added ion conductors exhibited higher ion conductivity compared to Comparative Examples 1, 2, and 5; in the case of Example 4 using the composite solid polymer electrolyte of Preparation Example 12 with 10 wt% fluorine added, the ion conductivity was 4.8 x 10⁻⁶. -4It showed the best ion conductivity with S / cm.

[0172] (Evaluation Example 3) Evaluation of weight loss rate according to temperature

[0173] The weight loss rate according to temperature was measured by thermogravimetric analysis (TGA) of the composite solid polymer electrolyte and is shown in Table 5 and Figure 8 below.

[0174] Composite Solid Polymer Electrolyte Composition Type Weight Loss Rate (wt.%) 200℃ 250℃ Comparative Example 1 Preparation Example 4 (P2PE8) 2.6 8.9 Comparative Example 2 Preparation Example 5 (P3PE7) 1.3 4.5 Comparative Example 3 Preparation Example 6 (P4PE6) 2.3 7.2 Comparative Example 5 Preparation Example 10 (P3PE7 - 0 wt.% F-LASTP) 6.5 12.8 Example 3 Preparation Example 11 (P3PE7 - 5 wt.% F-LASTP) 8.0 16.1 Example 4 Preparation Example 12 (P3PE7 - 10 wt.% F-LASTP) 1.9 2.3

[0175] Referring to Table 5 and Figure 8, when using a composite solid polymer electrolyte containing an ion conductor with 10 wt% fluorine and mixed with PEO and PEGDME in a weight ratio of 30:70 as in Example 4, the lowest weight loss rate was observed at 250°C, indicating the best thermal stability. Accordingly, it was confirmed that the stability of the battery can be improved even when abnormal heat generation, such as overheating or thermal runaway, occurs.

[0176] (Evaluation Example 4) Electrochemical Performance Evaluation

[0177] The electrochemical performance of solid polymer batteries according to Examples 7, 8, 11, Comparative Example 6, Comparative Example 7, and Comparative Example 10 was evaluated and is shown in Table 6 and Figure 9.

[0178] Specifically, Table 6 shows the capacity retention rate of the solid polymer battery at 100 cycles, and Figure 9(a) is a graph showing the cycle performance of the solid polymer battery according to Example 7 (■) and Example 8 (●). To measure the cycle performance and capacity retention rate, charge-discharge cycles were performed five times at 0.05C initially, and then the cycle performance of the battery was evaluated at 0.1C.

[0179] Composite Solid Polymer Electrolyte Composition Type Capacity Retention Rate (%, at 100 cycles) Comparative Example 6 Preparation Example 4 (P2PE8) 88.9% Comparative Example 7 Preparation Example 5 (P3PE7) 82.4% Comparative Example 10 Preparation Example 10 (P3PE7-0 wt.% F-LASTP) 94.8% Example 7 Preparation Example 11 (P3PE7-5 wt.% F-LASTP) 99.0% Example 8 Preparation Example 12 (P3PE7-10 wt.% F-LASTP) 98.9%

[0180] As shown in Table 6 and Figure 9(a), in Comparative Examples 6 and 7, where the composite solid polymer electrolyte did not contain an ion conductor, the capacity retention rate at 100 cycles was low at less than 90%, and in Comparative Example 10, where the composite solid polymer electrolyte contained an ion conductor without fluorine, the capacity retention rate was measured to be less than 95%. However, in Examples 7 and 8, where the composite solid polymer electrolyte containing an ion conductor with fluorine was used, the capacity retention rates at 100 cycles were measured to be 99.0% and 98.9%, respectively, confirming that cycle stability was significantly improved.

[0181] Figures 9(b) and 9(c) respectively show (b) a graph measuring the rate capability characteristics of the solid polymer battery according to Example 8 and (c) a charge-discharge curve according to the change in the charge-discharge rate (c-rate). Referring to Figures 9(b) and 9(c), it was observed that the solid polymer battery of Example 8 exhibited high-rate characteristics by fully recovering its initial capacity when the charge-discharge rate was changed to 0.2C, after increasing the charge-discharge rate of the battery to 0.05C, 0.1C, 0.2C, 0.5C, 1C, and 2C every 5 cycles. Since a high-quality SEI (Solid-Electrolyte Interface) layer was formed on the electrode surface by operating at 0.05C during the initial cycle for 5 cycles, the battery capacity showed a tendency to increase even though the charge-discharge rate was increased to 0.1C in the 6th cycle.

[0182] In addition, FIG. 9(d) is a charge-discharge curve of the solid polymer battery according to Example 11 in the voltage range of 2.5 to 4.7 V. Referring to FIG. 9(d), the solid polymer battery of Example 11 exhibited high capacity characteristics and operated stably in the high voltage range of 2.5 to 4.7 V. In particular, it was confirmed that the battery operated well without decomposition of the electrolyte even at high voltages of 4.7 V or higher, and it was confirmed that the developed composite solid polymer electrolyte enables the realization of a high energy density battery.

[0183] (Evaluation Example 5) Electrochemical Stability Window Evaluation

[0184] To evaluate electrochemical stability, electrochemical linear scanning potentiometry (LSV) was performed on solid polymer batteries according to Examples 9, 10, and Comparative Examples 11 to 13 to obtain voltage-current curves. The LSV experiments were conducted at a scan rate of 1 mV / s at 0 to 6 V (vs. Li / Li + The test was performed by applying voltage within the range. The measurement results are shown in Figure 10 and Table 7 below.

[0185] Composite Solid Polymer Electrolyte Composition Type Electrochemical Stability Window Comparative Example 11 Preparation Example 4 (P2PE8) 4.5 V Comparative Example 12 Preparation Example 5 (P3PE7) 4.6 V Comparative Example 13 Preparation Example 10 (P3PE7-0 wt.% F-LASTP) 5.1 V Example 9 Preparation Example 11 (P3PE7-5 wt.% F-LASTP) 5.3 V Example 10 Preparation Example 12 (P3PE7-10 wt.% F-LASTP) 6.7 V

[0186] Referring to Figure 10 and Table 7, the electrochemical stability window of the solid polymer battery according to Example 9 was improved to 5.3 V, and the electrochemical stability window of the solid polymer battery of Example 10 using the composite solid polymer electrolyte composition of Preparation Example 12, which had 10 wt% fluorine added, was significantly improved to 6.7 V, confirming that the electrochemical window was enhanced compared to Comparative Examples 12 and 13.

[0187] As described above, the present invention has been explained by specific details, limited embodiments, and drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention and is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0188] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

1. Polymer matrix; and A lithium salt and an ion conductor dispersed within the above polymer matrix; comprising, The above ion conductor is a composite solid polymer electrolyte comprising an inorganic oxide-based compound with added fluorine.

2. In Paragraph 1, A composite solid polymer electrolyte in which the above-mentioned fluorine is dispersed within the crystal of an inorganic oxide-based compound.

3. In Paragraph 1, A composite solid polymer electrolyte in which the above-mentioned inorganic oxide-based compound is represented by the following chemical formula 1. [Chemical Formula 1] There 1+x+y To the x Yes y You 2-x P 3-y OR 12 (0 <x<2, 0<y<3) 4. In Paragraph 3, The above inorganic oxide-based compound is Li 1.5 Al 0.3 Si 0.2 Ti 1.7 P 2.8 O 12 Phosphorus, composite solid polymer electrolyte.

5. In Paragraph 1, The above ion conductor is a composite solid polymer electrolyte containing 0.1 to 1.0 parts by weight of fluorine based on 100 parts by weight of an inorganic oxide-based compound.

6. In Paragraph 1, The above ion conductor is a composite solid polymer electrolyte containing 0.1 to 1.5 atomic% of fluorine atoms.

7. In Paragraph 1, The above polymer matrix is ​​a composite solid polymer electrolyte containing a polyalkylene oxide-based polymer.

8. In Paragraph 7, A composite solid polymer electrolyte in which the polymer matrix comprises at least one of the terminal functional groups, a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer that are different from each other.

9. In Paragraph 8, A composite solid polymer electrolyte in which the first polyalkylene oxide-based polymer contains at least one hydroxyl group (-OH) among the terminal functional groups, and the second polyalkylene oxide-based polymer contains at least one alkoxy group among the terminal functional groups.

10. In Paragraph 8, The above-mentioned first polyalkylene oxide-based polymer is a composite solid polymer electrolyte in which one or more are selected from the group comprising polymethylene oxide (Poly(methylene Oxide, PMO), polyethylene oxide (Poly(ethylene Oxide, PEO), and polypropylene oxide (Poly(propylene Oxide, PPO).

11. In Paragraph 8, The above second polyalkylene oxide-based polymer is a composite solid polymer electrolyte comprising one or more selected from the group including poly(ethylene glycol) dimethyl ether, poly(ethylene glycol) diethyl ether, poly(ethylene glycol) dipropyl ether, poly(ethylene glycol) dibutyl ether, and poly(propylene glycol) dimethyl ether.

12. In Paragraph 8, The above first polyalkylene oxide-based polymer and second polyalkylene oxide-based polymer are a combination of polyethylene oxide (Poly(ethylene Oxide), PEO) and poly(ethyleneglycol) dimethyl ether (PEGDME), forming a composite solid polymer electrolyte.

13. In Paragraph 8, A composite solid polymer electrolyte in which the polymer matrix contains a first polyalkylene oxide-based polymer and a second polyalkylene oxide-based polymer in a weight ratio of 1:1.2 to 5.

7.

14. In Paragraph 1, The above polymer matrix is ​​a composite solid polymer electrolyte having a semi-interpenetrating polymer network (SIPN) structure.

15. In Paragraph 1, Ionic conductivity is 0.5 x 10 -4 Up to 5.0 x 10 -4 S / cm composite solid polymer electrolyte.

16. In Paragraph 1, A composite solid polymer electrolyte having a weight loss rate of less than 18 wt% at 150 to 350°C when subjected to thermogravimetric analysis at a heating rate of 10°C / min at 25 to 500°C.

17. A step of preparing a composite solid polymer electrolyte composition by mixing an ion conductor comprising a lithium salt, a polymer, and an inorganic oxide-based compound to which fluorine has been added in a solvent; and A method for manufacturing a composite solid polymer electrolyte comprising the step of drying the above composite solid polymer electrolyte composition.

18. In Paragraph 17, The above ion conductor is, (a) a step of preparing a calcined product by calcining a mixed powder comprising an inorganic oxide-based compound powder and a fluorine powder; and (b) a step of sintering the above-mentioned calcined material to produce an ion conductor; a method for producing a composite solid polymer electrolyte, comprising the above-mentioned step.

19. In Paragraph 18, The above step (a) is, (a-1) A step of heating the above mixed powder to a first temperature and calcining it first; and (a-2) a step of raising the temperature of the first calcined mixed powder to a second temperature and calcining it to produce a calcined product; comprising a method for manufacturing a composite solid polymer electrolyte.

20. In Paragraph 19, A method for manufacturing a composite solid polymer electrolyte, wherein the ratio (T2 / T1) of the first temperature (T1) and the second temperature (T2) is 1.2 to 3.

0.

21. In Paragraph 18, A method for manufacturing a composite solid polymer electrolyte, wherein the sintering in step (b) above is performed at a temperature of 900 to 1300 ℃.

22. In Paragraph 17, A method for manufacturing a composite solid polymer electrolyte, wherein, in the step of manufacturing the composite solid polymer electrolyte composition, an additive is further added.

23. A solid polymer battery comprising a composite solid polymer electrolyte according to any one of claims 1 to 16.

24. In Paragraph 23, A solid polymer battery having an electrochemical stability window (ESW) of 5.0 to 7.0 V with respect to lithium metal.

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