Polymer electrolyte and lithium metal battery comprising same

Abstract

Disclosed are a polymer electrolyte and a lithium metal battery comprising same, the polymer electrolyte comprising a crosslinked polymer including: a repeating unit (A) derived from a first crosslinkable monomer including three or more double bond functional groups including an ester bond; and a repeating unit (B) derived from a second crosslinkable monomer including two or more double bond functional groups including an ester bond.

Description

Polymer electrolyte and lithium metal battery containing the same

[0001] The present invention relates to a polymer electrolyte, a method for manufacturing the same, and a lithium metal battery including the same.

[0002] The recent rapid proliferation of battery-powered electronic devices, such as mobile phones, laptops, and electric vehicles, has led to a rapid increase in demand for high-energy density, high-capacity secondary batteries. Accordingly, active research and development is underway to improve the performance of lithium secondary batteries.

[0003] A lithium secondary battery is a battery that includes a positive electrode and a negative electrode that contain active materials capable of intercalating and deintercalating lithium ions, and an electrolyte, and produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated / deintercalated from the positive electrode and negative electrode.

[0004] Lithium batteries currently on the market primarily use carbon-based anode materials, such as graphite. Carbon-based anode materials exhibit no volume change during charge and discharge, contributing to the stability of lithium batteries. Graphite's theoretical capacity is relatively small, at around 372 mAh / g.

[0005] Lithium metal can be used as an anode active material. Lithium metal has a very high theoretical electrical capacity of approximately 3860 mAh / g. During charge / discharge, lithium metal can form dendrites on its surface due to side reactions with the electrolyte. These dendrites can then grow and cause short circuits between the anode and cathode. Consequently, the lifespan and thermal stability of lithium metal batteries containing lithium metal deteriorate.

[0006] A method for improving the life characteristics and thermal stability of a lithium metal battery containing lithium metal is required.

[0007] One aspect is to provide polymer electrolytes with improved stability.

[0008] Another aspect is to provide a lithium metal battery comprising the above-described polymer electrolyte.

[0009] According to one implementation example,

[0010] A polymer electrolyte is provided, comprising a crosslinked polymer comprising repeating units (A) derived from a first crosslinkable monomer comprising three or more double bond functional groups including an ester bond; and repeating units (B) derived from a second crosslinkable monomer comprising two or more double bond functional groups including an ester bond.

[0011] According to another implementation example,

[0012] A lithium metal battery is provided, comprising a positive electrode; a negative electrode; and the above-described polymer electrolyte interposed between the positive electrode and the negative electrode.

[0013] A polymer electrolyte according to one embodiment exhibits excellent high-temperature stability. Using this polymer electrolyte, a lithium metal battery with improved capacity retention, cycle life, and thermal stability can be manufactured.

[0014] Figure 1 schematically illustrates the structure of a cross-linked polymer constituting a polymer electrolyte according to an embodiment.

[0015] Figure 2 shows a cross-sectional view of a lithium battery according to an embodiment.

[0016] Figure 3 shows a cross-sectional view of a lithium battery according to an embodiment.

[0017] Figure 4 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0018] Figure 5 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0019] Figure 6 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0020] Figure 7 is a schematic diagram of a lithium battery according to an exemplary embodiment.

[0021] Hereinafter, a polymer electrolyte and a lithium battery containing the polymer electrolyte according to an exemplary embodiment will be examined in more detail. These examples are provided solely as illustrative examples to more specifically illustrate the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the present specification, including its definitions, shall prevail.

[0023] Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein. The singular expression "singular" includes plural expression unless the context clearly indicates otherwise.

[0024] In this specification, the terms "include" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material or combination thereof described in the specification, but should be understood to not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, ingredients, materials or combinations thereof.

[0025] The term "combination of these" in this specification means a mixture or combination of one or more of the described components.

[0026] As used herein, the term "and / or" is meant to include any and all combinations of one or more of the items described herein. As used herein, the term "or" means "and / or." The expressions "at least one," "one or more," or "one or more" preceding elements herein may supplement the entire list of elements and do not mean that they supplement individual elements described above.

[0027] In order to clearly represent various layers and regions in the drawings, the thicknesses are enlarged or reduced. The same drawing reference numerals are used for similar parts throughout the specification. When a layer, film, region, plate, etc. is referred to as being "on" or "above" another part throughout the specification, this includes not only cases where it is directly above the other part, but also cases where there is another part in between. The terms first, second, etc. may be used throughout the specification to describe various components, but the components should not be limited by the terms. The terms are used only to distinguish one component from another.

[0028] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0029] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0030] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0031] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0032] In this disclosure, “alloy” means a mixture of two or more metals.

[0033] In the present disclosure, “positive electrode material” means a positive electrode material capable of undergoing lithiation and delithiation.

[0034] In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

[0035] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to a positive electrode active material or a negative electrode active material.

[0036] In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from a positive electrode active material or a negative electrode active material.

[0037] In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

[0038] In this disclosure, “discharging” and “discharging” mean the process of removing electrochemical energy from a battery.

[0039] In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

[0040] In the present disclosure, “cathode” and “anode” mean electrodes where electrochemical oxidation and delithiation occur during the discharge process.

[0041] With reference to the attached drawings, exemplary polymer electrolytes and lithium batteries including the same will be described in more detail below.

[0042] [Polymer electrolyte]

[0043] The polymer electrolyte comprises a crosslinked polymer comprising repeating units (A) derived from a first crosslinkable monomer comprising three or more double bond functional groups including an ester bond; and repeating units (B) derived from a second crosslinkable monomer comprising two or more double bond functional groups including an ester bond.

[0044] For example, when the crosslinked polymer comprises repeating units (A) derived from a first crosslinkable monomer having three or more double bond functional groups including an ester bond; and repeating units (B) derived from a second crosslinkable monomer having two or more double bond functional groups including an ester bond, thermal stability can be improved. Accordingly, a lithium battery including the polymer electrolyte can have improved thermal stability characteristics and capacity retention characteristics.

[0045] For example, when the crosslinked polymer includes repeating units (A) derived from a crosslinkable monomer having three or more double bond functional groups including an ester bond and repeating units (B) derived from a crosslinkable monomer having two or more double bond functional groups including an ester bond, high temperature stability can be improved. For example, since the crosslinked polymer includes a double bond functional group including an ester bond rather than an ether bond, the reactivity of the crosslinkable monomer increases, so that the content of unreacted monomer remaining after the crosslinking reaction during the preparation of the crosslinked polymer can be reduced. Accordingly, side reactions due to unreacted monomers are prevented, so that the high temperature stability of the crosslinked polymer is further improved, and a lithium battery including the polymer electrolyte can have further improved high temperature capacity characteristics and high temperature life characteristics.

[0046] The crosslinked polymer may further comprise a repeating unit (C) derived from an ionic monomer comprising an ionic functional group and one double bond functional group.

[0047] For example, when the crosslinked polymer includes a repeating unit (C) derived from an ionic monomer having an ionic functional group and one double bond functional group, the ionic conductivity of the polymer electrolyte is improved, and lithium ions are uniformly deposited on an anode to be described later, thereby effectively preventing the formation of lithium dendrite. For example, since the ionic monomer includes one double bond functional group, a crosslinking reaction between ionic monomers is prevented, and the ionic monomers can be dispersed and arranged at the terminals of the main chain and side chains of the crosslinked polymer in the form of end-capping during the crosslinking reaction. Accordingly, charge unevenness due to aggregation of ionic monomers is prevented, and the repeating unit (B) derived from a uniformly matched ionic monomer uniformly improves the ionic conductivity of the polymer electrolyte, so that lithium ions can be uniformly deposited on an anode to be described later. Accordingly, the capacity characteristics and life characteristics of a lithium battery including the polymer electrolyte can be further improved.

[0048] Figure 1 schematically illustrates the structure of a cross-linked polymer constituting a polymer electrolyte according to an embodiment.

[0049] Referring to Fig. 1, the crosslinked polymer (1) may include a main chain (M) and a plurality of side chains (S) extending from the main chain (M). For example, the plurality of side chains (S) may include a side chain (S1) extending from the main chain (M) and a side chain (S2) extending from the side chain (S1) extending from the main chain (M).

[0050] Referring to Fig. 1, the main chain (M) and the plurality of side chains (S) may include a terminal portion (E) at which a crosslinking reaction or polymerization reaction is completed. For example, a repeating unit (C) derived from an ionic monomer may be disposed at one or more terminal portions (E) among the terminal portions (E) included in the main chain (S) and the plurality of side chains (M). For example, the crosslinking reaction or polymerization reaction is performed at a double bond functional group, and since the ionic monomer includes one double bond functional group, when the ionic monomer is crosslinked or polymerized in the crosslinked polymer, it no longer includes a site at which a crosslinking reaction or polymerization reaction is performed, and therefore, the repeating unit (C) derived from the ionic monomer may be disposed at one or more terminal portions (E) among the terminal portions (E) included in the main chain (S) and the plurality of side chains (M). For example, when a repeating unit (C) derived from the ionic monomer is arranged at one or more of the terminal portions (E) included in the main chain (S) and the plurality of side chains (M), the ionic monomer is uniformly distributed throughout the crosslinked polymer (1) rather than being aggregated, thereby uniformly improving the ionic conductivity of the polymer electrolyte including the crosslinked polymer (1). Accordingly, the life characteristics and capacity characteristics of a lithium battery including the polymer electrolyte can be improved.

[0051] According to one embodiment, the double bond functional group of the first crosslinking monomer and the second crosslinking monomer may include an acrylate group.

[0052] According to one embodiment, the double bond functional group of the first crosslinking monomer and the second crosslinking monomer may be represented by the following chemical formula 1.

[0053] <Chemical Formula 1>

[0054]

[0055] In chemical formula 1,

[0056] R1 is any one selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, and * is a bonding site with an adjacent atom.

[0057] According to one embodiment, R1 in the above chemical formula 1 may be hydrogen or an alkyl group having 1 to 20 carbon atoms.

[0058] According to one embodiment, R1 in the above chemical formula 1 may be hydrogen, a methyl group, an ethyl group, a propyl group, or a butyl group.

[0059] According to one embodiment, the first crosslinking monomer may include three of the double bond functional groups, and the second crosslinking monomer may include two of the double bond functional groups.

[0060] For example, when the first cross-linking monomer and the second cross-linking monomer include two or more double bond functional groups including an ester bond, the reactivity of the first cross-linking monomer and the second cross-linking monomer is further improved, so that the content of unreacted monomer can be more easily reduced. Accordingly, when the first cross-linking monomer and the second cross-linking monomer include two or more double bond functional groups including an ester bond, the high temperature stability of a polymer electrolyte including a cross-linked polymer including a repeating unit derived from the cross-linking monomer can be further improved.

[0061] According to one embodiment, the double bond functional group in the first crosslinkable monomer and the second crosslinkable monomer may not include an ether group (-O-). For example, the double bond functional group in the first crosslinkable monomer and the second crosslinkable monomer may include an ester group (-C(=O)-O-) and may not include an ether group (-O-). For example, when the double bond functional group in the first crosslinkable monomer and the second crosslinkable monomer includes an ether group (-O-) instead of an ester group (-C(=O)-O-), the content of unreacted monomers in the crosslinked polymer may increase, resulting in a decrease in high-temperature stability.

[0062] According to one embodiment, the first crosslinking monomer is trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate, trimethylolpropane propoxylate triacrylate, trimethylolpropane trimethacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate or pentaerythritol triacrylate, pentaerythritol ethoxylate tetraacrylate, dipentaerythritol pentaacrylate. (dipentaerythritol pentaacrylate), dipentaerythritol hexaacrylate, or any combination thereof.

[0063] According to one embodiment, the second crosslinking monomer may include polyethylene glycol diacrylate (PEG-DA), trimethylolpropane dimethacrylate, 1,4-butanediol diacrylate, dipropylene glycol diacrylate, polycaprolactone diacrylate, aliphatic urethane diacrylate, or any combination thereof.

[0064] According to one embodiment, the double bond functional group in the ionic monomer may include an allyl group, an acrylic group, a vinyl group, or any combination thereof. For example, the ionic monomer may include an acrylic group, a vinyl group, or any combination thereof.

[0065] According to one embodiment, the ionic functional group included in the ionic monomer may include a cationic functional group, an anionic functional group, or a combination thereof. For example, if the ionic monomer includes a cationic functional group, the ionic monomer may be a cationic monomer. For example, if the ionic monomer includes an anionic functional group, the ionic monomer may be an anionic monomer. For example, if the ionic monomer includes both a cationic functional group and an anionic functional group, the ionic monomer may be a zwitterionic monomer.

[0066] In one embodiment, the cationic functional group may include pyrrolidium, piperidinium, ammonium, imidazolium, phosphonium, or any combination thereof. For example, the cationic functional group may include pyrrolidium, piperidinium, ammonium, imidazolium, or any combination thereof.

[0067] According to one embodiment, the anionic functional group is trifluoromethanesulfonyl imide (TFSI), bis(fluorosulfonyl) imide (FSI), acetate, bromide (Br). - ), chloride (Cl - ), iodide (I - ), dicyanamide, hexafluorophosphate, tetrafluoroborate, hydrogen sulfate, or any combination thereof. For example, the anionic functional group may include trifluoromethanesulfonyl imide (TFSI), bis(fluorosulfonyl) imide (FSI), or a combination thereof.

[0068] According to one embodiment, the ionic monomer may include a cationic monomer or a zwitterionic monomer. For example, when the ionic monomer includes a cationic monomer, the cationic monomer may include a cationic functional group and a double bond functional group. For example, when the ionic monomer includes a zwitterionic monomer, the zwitterionic monomer may include an anionic functional group, a cationic functional group, and a double bond functional group.

[0069] In one embodiment, the ionic monomer may comprise a cationic monomer and an anion. In this case, the cationic monomer may comprise a cationic functional group and a double bond functional group. The anion may comprise the anionic functional group. For example, the anion may be the anionic functional group.

[0070] According to one embodiment, the ionic monomer may include a cationic monomer such as a pyrrolidium-allyl monomer, a pyrrolidium-acrylate monomer, an ammonium-aryl monomer, an ammonium-acrylate monomer, or any combination thereof. In this case, the ionic monomer may include an anionic monomer such as trifluoromethanesulfonyl imide (TFSI), bis(fluorosulfonyl) imide (FSI), acetate, or bromide (Br). - ), chloride (Cl - ), iodide (I - ), dicyanamide, hexafluorophosphate, tetrafluoroborate, hydrogen sulfate, or any combination thereof.

[0071] For example, a pyrrolidium-allyl monomer may contain allyl and pyrrolidium in one monomer. For example, a pyrrolidium-acrylate monomer may contain acrylate and pyrrolidium in one monomer. For example, an ammonium-allyl monomer may contain allyl and ammonium in one monomer. For example, an ammonium-acrylate monomer may contain acrylate and ammonium in one monomer.

[0072] In one embodiment, the ionic monomer may include a cationic monomer such as 1-allyl-1-methylpyrrolidinium, dimethyl[2-(methacryloyloxy)ethyl]propylaminium, 1-allyl-3-methylimidazolium, 3-ethyl-1-vinylimidazolium, N,N,N,N-butyldimethylmethacryloyloxyethylammonium, or a combination thereof. For example, the cationic monomer may be dimethyl[2-(methacryloyloxy)ethyl]propylaminium. In this case, the ionic monomer may include trifluoromethanesulfonyl imide (TFSI) or bis(fluorosulfonyl) imide (FSI) as an anion.

[0073] According to one embodiment, the weight ratio of the repeating unit (A) derived from the first crosslinkable monomer included in the crosslinked polymer to the repeating unit (B) derived from the second crosslinkable monomer may be 5:5 to 8:2. For example, the weight ratio of the repeating unit (A) derived from the first crosslinkable monomer included in the crosslinked polymer to the repeating unit (B) derived from the second crosslinkable monomer may be 5:5 to 8:2, 5:5 to 7.5:2, 5:5 to 7.5:2, or 5:5 to 7:2. For example, when the weight ratio of the repeating unit (A) derived from the first crosslinkable monomer included in the crosslinked polymer to the repeating unit (B) derived from the second crosslinkable monomer is satisfied, the polymer electrolyte including the crosslinked polymer may have improved high-temperature stability.

[0074] According to one embodiment, the weight ratio of the sum of the weights of the repeating units (A) derived from the first crosslinkable monomer and the repeating units (B) derived from the second crosslinkable monomer included in the crosslinked polymer to the weight of the repeating units (C) derived from the ionic monomer may be from 2:1 to 12:1. For example, the weight ratio of the sum of the weights of the repeating units (A) derived from the first crosslinkable monomer and the repeating units (B) derived from the second crosslinkable monomer included in the crosslinked polymer to the weight of the repeating units (C) derived from the ionic monomer may be from 2:1 to 12:1, from 3:1 to 10:1, from 4:1 to 9:1, or from 5:1 to 9:1. For example, when the sum of the weights of the repeating units (A) derived from the first crosslinking monomer and the repeating units (B) derived from the second crosslinking monomer is greater than the weight of the repeating units (C) derived from the ionic monomer, the polymer electrolyte including the crosslinked polymer can have improved high-temperature stability and lifespan characteristics by minimizing unreacted ionic monomers.

[0075] According to one embodiment, the weight part of the first crosslinking monomer may be 50 to 99 weight parts based on 100 weight parts of the crosslinking polymer.

[0076] For example, the weight part of the first crosslinking monomer (or the weight part of the advantageous repeating unit (A) from the first crosslinking monomer) relative to 100 weight parts of the crosslinked polymer may be 50 to 99 weight parts, 50 to 95 weight parts, 60 to 90 weight parts, 60 to 80 weight parts, or 60 to 70 weight parts. A crosslinked polymer satisfying the above weight parts may have excellent high-temperature capacity retention characteristics and thermal stability.

[0077] The above crosslinked polymer may further comprise a repeating unit (D) derived from a third crosslinkable monomer comprising a double bond functional group and a P element.

[0078] According to one embodiment, the third crosslinking monomer may be 2-hydroxyethyl methacrylate phosphate.

[0079] The polymer electrolyte may further include one or more selected from an organic solvent, an ionic liquid, a polymer ionic liquid, and an inorganic particle.

[0080] According to one embodiment, the polymer electrolyte further comprises a lithium salt. Here, the content of the lithium salt is 20 to 100 parts by weight based on 100 parts by weight of the copolymer. For example, when the polymer electrolyte comprises a lithium salt, the polymer electrolyte may be a polymer solid electrolyte comprising a lithium salt.

[0081] The polymer solid electrolyte may, for example, comprise a mixture of a lithium salt and the cross-linked polymer described above. The polymer solid electrolyte may, for example, be a polymer electrolyte that does not comprise a liquid electrolyte.

[0082] According to one embodiment, the polymer solid electrolyte may include a polymer in addition to the cross-linked polymer described above. For example, the polymers include polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), poly(styrene-b-ethylene oxide) block copolymer (PS-PEO), poly(styrene-butadiene), poly(styrene-isoprene-styrene), poly(styrene-b-divinylbenzene) block copolymer, poly(styrene-ethylene oxide-styrene) block copolymer, polystyrene sulfonate (PSS), polyvinyl fluoride (PVF), polymethyl methacrylate (PMMA), poly(methylmethacrylate), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), polyaniline, Polyacetylene, Nafion, Aquivion, Flemion, Gore, Aciplex, Morgane ADP, sulfonated poly(ether ether ketone) (SPEEK), sulfonated poly(arylene ether ketone ketone sulfone) (SPAEKKS), sulfonated poly(aryl ether ketone) (SPAEK), poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI), poly(styrene sulfonate) (PSS), lithium 9,10-diphenylanthracene-2-sulfonate (lithium 9,10-diphenylanthracene-2-sulfonate, DPASLi) +) or a combination thereof, but is not limited thereto, and any polymer electrolyte used in the relevant technical field is possible.

[0083] For example, the lithium salt can be anything that can be used as a lithium salt in the relevant technical field. The lithium salt is a substance that dissolves in an organic solvent and acts as a source of lithium ions in the battery, enabling the basic operation of a lithium secondary battery and promoting the movement of lithium ions between the positive and negative electrodes. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalato)phosphate (LiDFOB), lithium bis(oxalato)borate (LiBOB).

[0084] According to one embodiment, the polymer electrolyte may further comprise a liquid electrolyte. For example, the polymer electrolyte may be a gel polymer electrolyte comprising the cross-linked polymer described above and a liquid electrolyte. For example, the liquid electrolyte may be disposed within a cross-linked network formed by the cross-linked polymer.

[0085] According to one embodiment, the liquid electrolyte may include an organic solvent or an ionic liquid. For example, the liquid electrolyte may further include the lithium salt described above. For example, the liquid electrolyte may be an ionic liquid, a mixture of a lithium salt and an ionic liquid, a mixture of a lithium salt and an organic solvent, a mixture of an ionic liquid and an organic solvent, or a mixture of a lithium salt, an ionic liquid, and an organic solvent.

[0086] According to one embodiment, the liquid electrolyte comprises a non-aqueous organic solvent and a lithium salt.

[0087] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0088] The above non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof.

[0089] Examples of the above carbonate solvents that can be used include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).

[0090] Ester solvents that can be used include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, and caprolactone.

[0091] Examples of ether solvents that can be used include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran. In addition, examples of ketone solvents that can be used include cyclohexanone. Examples of alcohol solvents that can be used include ethyl alcohol and isopropyl alcohol, and examples of aprotic solvents that can be used include nitriles such as R-CN (where R is a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane and 1,4-dioxolane; and sulfolanes.

[0092] The above non-aqueous organic solvents can be used alone or in combination of two or more.

[0093] In addition, when using a carbonate solvent, a cyclic carbonate and a chain carbonate can be mixed and used, and the cyclic carbonate and the chain carbonate can be mixed in a volume ratio of 1:1 to 1:9.

[0094] For example, the ionic liquid refers to a salt or a molten salt in a liquid state at room temperature that has a melting point below room temperature and is composed only of ions. The ionic liquid may comprise at least one selected from compounds comprising, for example, a) at least one cation selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) at least one anion selected from BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, BF4-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-. For example, the ionic liquid may be 1-butyl-3-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide.

[0095] For example, the polymer solid electrolyte may be impregnated into an electrolyte solution within a lithium battery to form a gel polymer electrolyte. The gel polymer electrolyte may further include inorganic particles.

[0096] According to one embodiment, the polymer electrolyte may further include a solid electrolyte.

[0097] The solid electrolyte is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, or a combination thereof.

[0098] Solid electrolytes are, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes are Li 1+x+y Al x Ti 2-x Si y P 3-y O 12(0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(O≤x<1, O≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10) is one or more selected from. The solid electrolyte is manufactured by a sintering method, etc. For example, the oxide-based solid electrolyte is Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 A garnet-type solid electrolyte selected from (M doped LLZO, M=Ga, W, Nb, Ta, or Al, x is an integer from 1 to 10).

[0099] The sulfide-based solid electrolyte may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or a combination thereof. The sulfide-based solid electrolyte particles may include Li2S, P2S5, SiS2, GeS2, B2S3, or a combination thereof. The sulfide-based solid electrolyte particles may be Li2S or P2S5. Sulfide-based solid electrolyte particles are known to have high lithium ion conductivity compared to other inorganic compounds. For example, the sulfide-based solid electrolyte includes Li2S and P2S5. When the sulfide solid electrolyte material constituting the sulfide-based solid electrolyte includes Li2S-P2S5, the mixing molar ratio of Li2S to P2S5 may be, for example, in a range of about 50:50 to about 90:10. In addition, Li3PO4, halogen, halogen compound, Li 2+2x Zn 1-x GeO4("LISICON", 0혎<1), Li 3+y PO 4-x N x( "LIPON", 0 <x<4, 0<y<3), Li 3.25 Ge 0.25 P 0.75 S4("ThioLISICON"), Li2O-Al2O3-TiO2-P2O 5( An inorganic solid electrolyte prepared by adding "LATP") etc. to an inorganic solid electrolyte of Li2S-P2S5, SiS2, GeS2, B2S3, or a combination thereof can be used as a sulfide solid electrolyte. Non-limiting examples of sulfide solid electrolyte materials include Li2S-P2S5; Li2S-P2S5-LiX (X=halogen element); Li2S-P2S5-Li2O; Li2S-P2S5-Li2O-LiI; Li2S-SiS2; Li2S-SiS2-LiI; Li2S-SiS2-LiBr; Li2S-SiS2-LiCl; Li2S-SiS2-B2S3-LiI; Li2S-SiS2-P2S5-LiI; Li2S-B2S3; Li2S -P2S5-Z m S n(0 <m<10, 0<n<10, Z=Ge, Zn 또는 Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; 및 Li2S-SiS2-Li p MO q (0 <p<10, 0<q<10, M=P, Si, Ge, B, Al, Ga 또는 In)을 포함한다. 이와 관련하여, 황화물계 고체전해질 재료는 황화물계 고체전해질 물질의 원료 시작 물질(예를 들면, Li2S, P2S5, 등)을 용융 담금질법(melt quenching method), 기계적 밀링법 등에 의해 처리함으로써 제조될 수 있다. 또한, 소성(calcinations) 공정이 상기 처리 후에 수행될 수 있다. 황화물계 고체전해질은 비정질이거나, 결정질이거나, 이들이 혼합된 상태일 수 있다.

[0100] According to one embodiment, the polymer electrolyte is useful as a polymer electrolyte of a lithium battery. For example, the lithium battery may be a lithium metal battery or a non-anode lithium metal battery.

[0101] For example, the lithium battery may include a lithium-air battery, a lithium-ion battery, a lithium polymer battery, a lithium sulfur battery, etc., all of which use lithium electrodes.

[0102] The polymer electrolyte according to one embodiment can be used as a protective film for a lithium electrode or as an electrolyte. The polymer electrolyte has excellent interfacial properties and a high lithium transfer constant, and thus can have excellent lithium ion transfer capability.

[0103] [Method for producing polymer electrolyte]

[0104] A method for manufacturing a polymer electrolyte according to an embodiment of the present invention will be described.

[0105] A first crosslinking monomer including three or more double bond functional groups including an ester bond and a second crosslinking monomer including two or more double bond functional groups including an ester bond are mixed, and a polymerization initiator is added thereto to obtain a polymer electrolyte composition, and a polymerization reaction of the composition is performed.

[0106] The mixing ratio of the first crosslinking monomer including three or more double bond functional groups including an ester bond and the second crosslinking monomer including two or more double bond functional groups including an ester bond is controlled so as to correspond to the mixing ratio of the repeating unit (A) and the repeating unit (B) in the desired crosslinked polymer.

[0107] According to one embodiment, the molar ratio of the first crosslinking monomer including three or more double bond functional groups including an ester bond and the second crosslinking monomer including two or more double bond functional groups including an ester bond may be 5:5 to 9:1, 5:5 to 8:1, 5:5 to 7:3, or more than 5:5 and less than or equal to 7:3.

[0108] For a description of the first crosslinking monomer comprising three or more double bond functional groups including an ester bond and the second crosslinking monomer comprising two or more double bond functional groups including an ester bond, refer to the above description.

[0109] The polymerization reaction can be carried out by applying heat or irradiating light, such as UV light. Here, heat or light can be applied within a range that does not negatively affect the lithium metal electrode. For example, the polymerization reaction can be carried out by applying heat.

[0110] The above polymerization reaction may be a copolymerization reaction, a crosslinking reaction or a grafting reaction.

[0111] When heat is applied or light such as UV is irradiated to carry out a polymerization reaction, the heat or light may be applied within a range that does not negatively affect the lithium metal electrode.

[0112] According to another embodiment, it is also possible to carry out a polymerization reaction of the polymers by irradiating light at room temperature (25°C). A photopolymerization initiator is used during the crosslinking reaction by irradiating light. The photopolymerization initiator may be any compound that can form radicals by light such as ultraviolet rays, without limitation on its composition. As the photopolymerization initiator, for example, one or more selected from the group consisting of 2-hydroxy2-methyl-1-phenyl-propan-1-one (HMPP), benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine, and α-aminoketone may be used. The above acylphosphine may be, for example, 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide.

[0113] As the above thermal polymerization initiator, one or more selected from the group of initiators consisting of a persulfate initiator, an azo initiator, hydrogen peroxide, benzoyl peroxide (BPO), tert-butyl peroxypivalate (t-BPP), and ascorbic acid can be used. Specifically, examples of persulfate-based initiators include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8), and examples of azo-based initiators include 2, 2-azobis-(2-amidinopropane) dihydrochloride, 2, 2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitril, 2, Examples include 2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 4,4-azobis-(4-cyanovaleric acid), and 2,2-azobis-(2-methylpropionitrile) (AIBN, (2,2 -Azobis(2-methylpropionitrile)).

[0114] A lithium salt may be added to the above polymer electrolyte composition.

[0115] A liquid electrolyte may be added to the above polymer electrolyte composition.

[0116] The crosslinked polymer may further include repeating units (C) derived from ionic monomers, by mixing in an ionic monomer during the polymerization reaction.

[0117] The crosslinked polymer may further include a repeating unit (D) derived from a third crosslinking monomer containing a double bond functional group and a P element, by further mixing a third crosslinking monomer during the polymerization reaction.

[0118] For descriptions of the lithium salt, the liquid electrolyte, the ionic monomer, and the third crosslinking monomer, refer to the above-described description.

[0119] [Lithium battery]

[0120] A lithium battery according to one embodiment includes a positive electrode; a negative electrode; and the above-described solid electrolyte disposed between the positive electrode and the negative electrode. By including the above-described solid electrolyte, the lithium battery can simultaneously provide improved capacity and excellent room temperature and high temperature lifespan characteristics.

[0121] Lithium batteries may be, but are not limited to, lithium primary batteries, lithium secondary batteries, lithium-sulfur batteries, lithium-air batteries, etc., and any lithium battery used in the relevant technical field may be used.

[0122] Lithium batteries are manufactured by, for example, the following exemplary methods, but are not necessarily limited to these methods and are adjusted according to required conditions.

[0123] Referring to FIGS. 2 and 3, a lithium battery according to an embodiment will be described in detail.

[0124] For example, referring to FIG. 2, the lithium battery may be a non-anode lithium metal battery (100). For example, referring to FIG. 3, the lithium battery may be a lithium metal battery (200).

[0125] A lithium battery according to one embodiment may include a positive electrode; a negative electrode; and a polymer electrolyte disposed between the positive electrode and the negative electrode, and the polymer electrolyte described above.

[0126] According to one embodiment, the polymer electrolyte may have a solid, liquid or gel form.

[0127] A lithium battery (100) according to an embodiment may include, as shown in FIG. 2, a negative electrode current collector (110); a polymer electrolyte (120) disposed on the negative electrode current collector (110); and a positive electrode (150) disposed on the polymer electrolyte (120). In this case, the negative electrode may include a negative electrode current collector (110) free of a negative electrode active material layer, and the positive electrode (250) may include a positive electrode current collector (140) and a positive electrode active material layer (130) disposed on the positive electrode current collector (140).

[0128] According to one embodiment, a lithium battery (200) may further include a lithium metal layer (225) disposed between a negative electrode current collector (210) and an electrolyte (220), as shown in FIG. 3. In this case, the negative electrode may include a negative electrode current collector (210); and a lithium metal layer (225) disposed between the negative electrode current collector (210) and the electrolyte (220). For example, the lithium battery (200) may include a negative electrode current collector (110), a lithium metal layer (225) disposed on the negative electrode current collector (110), a polymer electrolyte (120) disposed on the lithium metal layer (225); and a positive electrode (150) disposed on the polymer electrolyte (120). For example, the lithium metal layer (225) may include lithium metal or a lithium alloy. For example, the metal layer (225) may be dissociated into lithium ions and metal cations during the discharge process, so that the thickness of the lithium metal layer (225) may decrease. Conversely, the lithium metal layer (225) may be electrodeposited with lithium ions during the charge process, so that the thickness of the lithium metal layer (225) may increase.

[0129] According to one embodiment, a lithium battery (100, 200) including the above-described polymer electrolyte may further include a protective layer (not shown) disposed between the negative electrode and the polymer electrolyte during a charge / discharge process.

[0130] Referring to FIG. 1, the protective layer (not shown) can be formed between the negative electrode collector (110) and the polymer electrolyte (120).

[0131] Referring to FIG. 2, the protective layer (not shown) may be formed between the negative electrode current collector (110) and the polymer electrolyte (120). For example, the protective layer (not shown) may be formed between the lithium metal layer (225) and the polymer electrolyte (120).

[0132] [Cathode current collector (110, 210)]

[0133] For example, the material constituting the negative electrode current collector (110, 210) can be any material that does not react with lithium, that is, any material that does not form an alloy or compound with lithium and has conductivity. The metal substrate is, for example, a metal or an alloy. The metal substrate can be made of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The electrode current collector (200) can have a shape selected from, for example, a sheet, a foil, a film, a plate, a porous body, a mesoporous body, a body containing through-holes, a polygonal ring body, a mesh body, a foam body, and a non-woven body, but is not necessarily limited to these shapes, and any shape used in the relevant technical field can be used.

[0134] For example, the negative electrode current collector (110, 210) may have a reduced thickness compared to the negative electrode current collector included in a conventional negative electrode. Therefore, the negative electrode according to the present disclosure is distinguished from the conventional electrode including a thick film current collector, for example, by including a thin film current collector. Since the electrode according to one embodiment employs a thin film current collector having a reduced thickness, the thickness of the negative electrode active material layer in the negative electrode including the thin film current collector is relatively increased. As a result, the energy density of a lithium metal battery employing such an electrode is increased. The thickness of the negative electrode current collector (110, 210) may be, for example, less than 15 um, 14.5 um or less, or 14 um or less. The thickness of the negative electrode current collector (110, 210) may be, for example, less than 0.1 um to 15 um, 1 um to 14.5 um, 2 um to 14 um, 3 um to 14 um, 5 um to 14 um, or 10 um to 14 um.

[0135] The material constituting the negative electrode collector (110, 210) may be any material that does not react with lithium, i.e., does not form an alloy or compound with lithium, and has conductivity. The negative electrode collector (110, 210) is, for example, a metal or an alloy. The negative electrode collector (210) may be made of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0136] The negative electrode current collector (110, 210) may have a form selected from, for example, a sheet, a foil, a film, a plate, a porous body, a mesoporous body, a body containing through holes, a polygonal ring body, a mesh body, a foam body, and a non-woven body, but is not necessarily limited to these forms, and any form used in the relevant technical field is possible.

[0137] The negative electrode current collector (110, 210) may include, for example, a base film and a metal substrate layer disposed on one or both sides of the base film. The negative electrode current collector (110, 210) includes a substrate, and the substrate may have a structure including, for example, a base film and a metal substrate layer disposed on one or both sides of the base film. An intermediate layer may additionally be disposed on the metal substrate layer.

[0138] For example, the base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. Since the base film includes a thermoplastic polymer, the base film can melt when a short circuit occurs, thereby suppressing a sudden increase in current. The base film may be, for example, an insulator. The metal substrate layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The metal substrate layer may act as an electrochemical fuse, which may be cut in the event of an overcurrent to prevent a short circuit. The limit current and maximum current can be controlled by controlling the thickness of the metal substrate layer. The metal substrate layer may be plated or deposited on the base film. When the thickness of the metal substrate layer is reduced, the limit current and / or maximum current of the negative electrode current collector (110, 210) decreases, thereby improving the stability of the lithium metal battery in the event of a short circuit. A lead tab may be added on the metal substrate layer for connection to the outside. The lead tab may be welded to the metal substrate layer or the metal substrate layer / base film laminate by ultrasonic welding, laser welding, spot welding, etc. During welding, the base film and / or the metal substrate layer may be melted, so that the metal substrate layer may be electrically connected to the lead tab. In order to make the welding of the metal substrate layer and the lead tab more solid, a metal chip may be added between the metal substrate layer and the lead tab. The metal chip may be a thin piece of the same material as the metal of the metal substrate layer. The metal chip may be, for example, a metal foil, a metal mesh, etc.The metal piece may be, for example, aluminum foil, copper foil, SUS foil, etc. After arranging the metal piece on the metal substrate layer, the lead tab may be welded to the metal piece / metal substrate layer laminate or the metal piece / metal substrate layer / base film laminate by welding the metal piece with the lead tab. During welding, the base film, the metal layer, and / or the metal piece may melt, so that the metal layer or the metal layer / metal piece laminate may be electrically connected to the lead tab. A metal chip and / or a lead tab may be added to a portion of the metal substrate layer. The base film may have a thickness of, for example, 1 to 50 ㎛, 1.5 to 50 ㎛, 1.5 to 40 ㎛, or 1 to 30 ㎛. When the base film has a thickness in this range, the weight of the negative electrode assembly can be more effectively reduced. The melting point of the base film may be, for example, 100 to 300°C, 100 to 250°C or less, or 100 to 200°C. Since the base film has a melting point within this range, the base film can be melted and easily bonded to the lead tab during the process of welding the lead tab. To improve the adhesion between the base film and the metal substrate layer, a surface treatment such as corona treatment may be performed on the base film. The thickness of the metal substrate layer may be, for example, 0.01 to 3 μm, 0.1 to 3 μm, 0.1 to 2 μm, or 0.1 to ㎛. Since the metal substrate layer has a thickness within this range, conductivity can be maintained while ensuring the stability of the negative electrode. The thickness of the metal piece may be, for example, 2 to 10 μm, 2 to 7 μm, or 4 to 6 μm. Since the metal piece has a thickness within this range, the connection between the metal layer and the lead tab can be performed more easily. By having this structure, the negative electrode collector (110, 210) can reduce the weight of the electrode and consequently improve the energy density.

[0139] According to one embodiment, the negative electrode current collector (110, 220) may be free of a negative electrode active material layer before performing charge / discharge. For example, the negative electrode current collector (110, 220) may be free of a lithium metal layer (225) before performing charge / discharge. For example, in the case of a non-anode lithium metal battery in which the negative electrode active material layer or the lithium metal layer (225) is free on the negative electrode current collector (110, 220) before performing charge / discharge, dendrite formation can be prevented, thereby further improving the life characteristics.

[0140] According to another embodiment, a lithium metal layer (225) including a plate-shaped lithium metal thin film may be disposed on the negative electrode current collector (210) before performing charge and discharge. For example, in the process of disposing a polymer electrolyte on the lithium metal layer (225) disposed on the negative electrode current collector (210), the metal cations included in the polymer electrolyte may react with the lithium metal layer (225), so that the metal cations may be precipitated as metal. The precipitated metal cations may be dissociated into metal cations during discharge.

[0141] According to one embodiment, the negative electrode may further include an interlayer disposed between the negative electrode current collector (210) and the lithium metal layer (225).

[0142] According to one embodiment, the interlayer may be directly disposed on, for example, one or both surfaces of the negative electrode collector (210). Accordingly, no other layer may be disposed between the negative electrode collector (210) and the interlayer. By directly disposing the interlayer on one or both surfaces of the negative electrode collector (210), the bonding force between the negative electrode collector (210) and the lithium metal layer (225) may be further enhanced.

[0143] The thickness of the intermediate layer (not shown) is, for example, 30% or less of the thickness of the negative electrode current collector (210). The thickness of the intermediate layer (not shown) is, for example, 0.01 to 30%, 0.1 to 30%, 0.5 to 30%, 1 to 25%, 1 to 20%, 1 to 15%, 1 to 10%, 1 to 5%, or 1 to 3% of the thickness of the negative electrode current collector (210). The thickness of the intermediate layer (not shown) is, for example, 10 nm to 5 ㎛, 50 nm to 5 ㎛, 200 nm to 4 ㎛, 500 nm to 3 ㎛, 500 nm to 2 ㎛, 500 nm to 1.5 ㎛, or 700 nm to 1.3 ㎛. By having the above intermediate layer (not shown) with a thickness in this range, the bonding force between the negative electrode current collector (210) and the metal layer (225) can be further improved, and an increase in interface resistance can be suppressed.

[0144] For example, the intermediate layer may include a binder. By including the binder in the intermediate layer, the bonding strength between the negative electrode current collector (210) and the lithium metal layer (225) may be further enhanced. The binder included in the intermediate layer (not shown) may be, for example, a conductive binder or a non-conductive binder.

[0145] The conductive binder may be, for example, an ion-conducting binder and / or an electron-conducting binder. A binder having both ion-conducting and electron-conducting properties may be classified as either an ion-conducting binder or an electron-conducting binder.

[0146] The ion-conducting binder is, for example, polystyrene sulfonate (PSS), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP, polyvinylidene fluoride-hexafluoropropylene), polyvinyl fluoride (PVF, polyvinylidene fluoride), polymethyl methacrylate (PMMA, poly(methylmethacrylate), polyethylene oxide (PEO, polyethylene oxide), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), polyacrylonitrile (PAN), polyaniline, and polyacetylene. The ion-conducting binder may include a polar functional group. Examples of the ion-conducting binder including a polar functional group include Nafion, Aquibion, etc. (Aquivion), Flemion, Gore, Aciplex, Morgane ADP, sulfonated poly(ether ether ketone) (SPEEK), sulfonated poly(arylene ether ketone ketone sulfone) (SPAEKKS), sulfonated poly(aryl ether ketone) (SPAEK), poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI), poly(styrene sulfonate) (PSS), lithium 9,10-diphenylatlacene-2-sulfonate 9,10-diphenylanthracene-2-sulfonate, DPASLi+), etc.Electronically conductive binders include, for example, polyacetylene, polythiophene, polypyrrole, poly(p-phenylene), poly(phenylenevinylene), poly(phenylenesulfide), polyaniline, etc. The intermediate layer may be a conductive layer comprising, for example, a conductive polymer.

[0147] The binder included in the intermediate layer may be, for example, a fluorinated binder. The fluorinated binder included in the intermediate layer may be, for example, polyvinylidene fluoride (PVDF). The intermediate layer may be disposed on the negative electrode current collector (210) in a dry or wet manner, for example. The intermediate layer may be, for example, a binding layer including a binder.

[0148] The intermediate layer may additionally include, for example, a carbon-based conductive material. By including the carbon-based conductive material, the intermediate layer may be, for example, a conductive layer. The intermediate layer may be, for example, a conductive layer including a binder and a carbon-based conductive material.

[0149] The intermediate layer may be disposed on the negative electrode current collector (210) in a dry manner, for example, by deposition such as CVD or PVD. The intermediate layer may be disposed on the negative electrode current collector (210) in a wet manner, for example, by spin coating, dip coating, or the like. The intermediate layer may be disposed on the negative electrode current collector (210) by, for example, depositing a carbon-based conductive material on the negative electrode current collector (210) by deposition. The dry-coated intermediate layer may be made of a carbon-based conductive material and may not include a binder. Alternatively, the intermediate layer may be disposed on the negative electrode current collector by, for example, coating a composition including a carbon-based conductive material, a binder, and a solvent on the surface of the negative electrode current collector and drying it. The intermediate layer may have a single-layer structure or a multi-layer structure including a plurality of layers.

[0150] [Cathode: Lithium metal layer]

[0151] Referring to FIG. 2, the lithium battery (200) may further include a metal layer (225) disposed between the negative electrode current collector (210) and the electrolyte (220). For example, the lithium metal layer (225) may include lithium metal or a lithium alloy. For example, the lithium metal layer (225) may be a negative electrode active material layer. For example, the lithium metal layer (225) may be a lithium electrodeposition layer.

[0152] For example, the lithium metal layer (225) may be generated when lithium ions included in the polymer electrolyte (120) are deposited on the negative electrode current collector (110) as the lithium battery (200) is charged. For example, the lithium metal layer (225) may include a lithium alloy and a lithium metal. For example, the lithium alloy included in the lithium metal layer (225) may weaken the reactivity of the lithium metal, thereby effectively preventing a side reaction between the lithium metal layer (225) and the polymer electrolyte (120). In addition, the lithium metal layer (225) has excellent electrical conductivity, so that the internal resistance of the lithium battery (200) including the lithium metal layer (225) may be reduced. Accordingly, the lithium battery (200) including the lithium metal layer (225) may have improved not only life characteristics but also charge and discharge efficiency.

[0153] According to one embodiment, the lithium metal layer (225) may include, for example, lithium foil, lithium powder, plated lithium, a carbon-based material, or a combination thereof. For example, the lithium metal layer (225) may include lithium foil. In this case, the lithium metal layer (225) may be a negative electrode active material layer. For example, the lithium metal layer (225) may be introduced by coating a slurry including lithium powder and a binder, etc., onto the negative electrode current collector (210). For example, the binder may be a fluorine-based binder such as polyvinylidene fluoride (PVDF).

[0154] According to one embodiment, the lithium metal layer (225) may include only a deposited lithium metal or lithium alloy. In this case, the lithium metal layer (225) may be a lithium deposition layer.

[0155] According to one embodiment, the lithium metal layer (225) may not include a carbon-based negative electrode active material. Accordingly, the lithium metal layer (225) may be formed of a metal-based negative electrode active material.

[0156] For example, the thickness of the lithium metal layer (225) may be, for example, 0.1 ㎛ to 100 ㎛, 0.1 ㎛ to 80 ㎛, 1 ㎛ to 80 ㎛, or 10 ㎛ to 80 ㎛, but is not necessarily limited to this range and may be adjusted according to the shape, capacity, etc. of the required lithium battery. If the thickness of the lithium metal layer (225) increases excessively, the structural stability of the lithium battery may deteriorate and side reactions may increase. If the thickness of the lithium metal layer (225) is excessively small, the energy density of the lithium metal battery may decrease.

[0157] According to one embodiment, the thickness of the lithium foil included in the lithium metal layer (225) may be, for example, 1 μm to 50 μm, 1 μm to 30 μm, or 10 μm to 30 μm, or 10 μm to 80 μm. When the lithium foil has a thickness in this range, the life characteristics of the lithium battery can be further improved.

[0158] According to one embodiment, the particle size of the lithium powder included in the lithium metal layer (225) may be, for example, 0.1 μm to 3 μm, 0.1 μm to 2 μm, or 0.1 μm to 2 μm. When the lithium powder has a thickness within this range, the life characteristics of the lithium battery can be further improved.

[0159] [Polymer electrolyte (120)]

[0160] For example, the polymer electrolyte (120) may include a crosslinked polymer as described above. The polymer electrolyte (120) may include a crosslinked network formed by the crosslinked polymer.

[0161] According to another embodiment, the polymer electrolyte (120) may further include a nonwoven fabric. The nonwoven fabric may serve to support at least one selected from lithium metal and lithium alloys precipitated during the charging process. For example, the nonwoven fabric may be omitted. For example, if the negative electrode current collector is of the mesh type, the nonwoven fabric may not be used.

[0162] The above nonwoven fabric may have a porosity of 10 to 90%, for example, 10 to 80%, for example, 10 to 50 vol%, for example, 25 to 50 vol%, and an average pore size of 0.1 to 10 µm, for example, 0.01 to 8 µm, for example, 0.1 to 1.0 µm. The average pore size represents the diameter when the pore shape is spherical, and represents the major axis length when the pore shape is non-spherical.

[0163] According to one embodiment, the nonwoven fabric may include one or more nonwoven fabrics selected from cellulose, polyester (e.g., polyethylene terephthalate (PET), polyetherimide, polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyacetal, polycarbonate, polyimide, polyetherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, polyacrylonitrile, nylon, and polyparaphenylenebenzobisoxazole.

[0164] [anode]

[0165] As shown in FIGS. 2 and 3, a positive electrode active material layer (130, 230) is disposed on a positive electrode current collector (140, 240) to form a positive electrode (150, 250). More specifically, a positive electrode active material layer (130, 230) may be disposed on a polymer electrolyte (120, 220), and a positive electrode current collector (140, 240) may be disposed on the positive electrode active material layer (130, 230).

[0166] [Anode: Anode current collector]

[0167] Referring to FIGS. 2 and 3, the positive electrode (150, 250) includes a positive electrode current collector (140, 240). For example, the positive electrode (150, 250) can be prepared by forming the positive electrode active material layer (130, 230) on the positive electrode current collector (140, 240).

[0168] For example, the positive electrode current collector (140, 240) may include indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0169] According to one embodiment, the positive electrode collector (140, 240) may include aluminum (Al).

[0170] For example, the positive electrode current collector (140, 240) may include a base film and a metal substrate layer disposed on one or both sides of the base film, similar to the negative electrode current collector (110, 220) described above.

[0171] [Anode: Anode active material layer]

[0172] The above positive electrode active material layer (130, 230) may include a positive electrode active material, a conductive material, and a binder.

[0173] As a cathode active material, a compound capable of reversible intercalation and deintercalation of lithium (lithiated intercalation compound) can be used. Specifically, at least one compound oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used. The compound oxide may be a lithium transition metal compound oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or combinations thereof.

[0174] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f)Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0175] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0176] For example, the cathode active material may be a high-nickel cathode active material in which the nickel content is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less, based on 100 mol% of metals excluding lithium in the lithium transition metal composite oxide. The high-nickel cathode active material can realize high capacity and thus can be applied to high-capacity, high-density lithium secondary batteries.

[0177] For example, the lithium transition metal oxide may be a compound represented by the following chemical formula 3:

[0178] <Chemical Formula 3>

[0179] Li a Ni x Co y M z O 2-b A b

[0180] In chemical formula 3, 1.0≤a≤1.2, 0≤b≤0.2, 0.6≤x<1, 0≤y≤0.3, 0 <z≤0.3, x+y+z=1, M은 망간(Mn), 바나듐(V), 마그네슘(Mg), 갈륨(Ga), 실리콘(Si), 텅스텐(W), 몰리브덴(Mo), 철(Fe), 크롬(Cr), 구리(Cu), 아연(Zn), 티타늄(Ti), 알루미늄(Al) 및 보론(B)으로 이루어진 군으로부터 선택된 하나 이상이고,

[0181] A is F, S, Cl, Br or a combination thereof.

[0182] For example, in chemical formula 3, 0.7≤x<1, 0 <y≤0.3, 0<z≤0.3; 0.8≤x<1, 0<y≤0.3, 0<z≤0.3; 0.8≤x<1, 0<y≤0.2, 0<z≤0.2; 0.83≤x<0.97, 0<y≤0.15, 0<z≤0.15; 또는 0.85≤x<0.95, 0<y≤0.1, 0<z≤0.1일 수 있다.

[0183] For example, the lithium transition metal oxide may be at least one of the compounds represented by the following chemical formulae 3-1 and 3-2:

[0184] <Chemical Formula 3-1>

[0185] LiNi x Co y Mn z O2

[0186] In Chemical Formula 3-1, 0.6≤x≤0.95, 0 <y≤0.2, 0<z≤0.1이다. 예를 들어, 0.7≤x≤0.95, 0<y≤0.3, 0<z≤0.3이고,

[0187] <Chemical Formula 3-2>

[0188] LiNi x Co y Al z O2

[0189] In Chemical Formula 3-2, 0.6≤x≤0.95, 0 <y≤0.2, 0<z≤0.1이다. 예를 들어, 0.7≤x≤0.95, 0<y≤0.3, 0<z≤0.3이다. 예를 들어, 0.8≤x≤0.95, 0<y≤0.3, 0<z≤0.3이다. 예를 들어, 0.82≤x≤0.95, 0<y≤0.15, 0<z≤0.15이다. 예를 들어, 0.85≤x≤0.95, 0<y≤0.1, 0<z≤0.1이다.

[0190] For example, lithium transition metal oxide is LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.88 Co 0.08 Mn0.04 O2, LiNi 0.8 Co 0.15 Mn 0.05 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.88 Co 0.1 Mn 0.02 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.8 Co 0.1 Mn 0.2 O2 or LiNi 0.88 Co 0.1 Al 0.02 It could be O2.

[0191] For example, the above cathode active material may be used as one having a coating layer on the surface of the lithium transition metal oxide, or may be used by mixing the lithium transition metal oxide and a lithium transition metal oxide having a coating layer.

[0192] For example, the coating layer may include a coating element compound of an oxide, a hydroxide, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a hydroxycarbonate of the coating element.

[0193] For example, the compound forming the coating layer may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or mixtures thereof. The coating layer forming process may use any coating method as long as it can coat the lithium transition metal oxide with the coating elements by a method (e.g., spray coating, dipping, etc.) that does not adversely affect the properties of the positive electrode active material. Since this is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0194] For example, the anode may further include an additive that can act as a sacrificial anode.

[0195] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0196] The above binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector. Representative examples of the binder include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride (PVDF), polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0197] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0198] [Separator]

[0199] A lithium battery according to an embodiment may further include a separator (not shown).

[0200] As such separators, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used, and of course, mixed multilayer films such as a polyethylene / polypropylene two-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, a polypropylene / polyethylene / polypropylene three-layer separator, etc. may be used.

[0201] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0202] The above porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof.

[0203] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0204] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from, but not limited to, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0205] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0206] According to one embodiment, a battery case containing a lithium battery may be classified into a cylindrical shape, a square shape, a thin-film shape, a coin shape, etc. For example, the lithium battery may be a large-scale thin-film type battery. The lithium battery may be a lithium ion battery.

[0207] According to an embodiment, the lithium battery (100, 200) may be, for example, a lithium-air battery, a lithium-sulfur battery, etc.

[0208] According to one embodiment, the lithium battery (100, 200) can be used in electric vehicles (EVs) due to its excellent lifespan and high-rate characteristics. For example, it can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring large amounts of power storage. For example, it can be used in electric bicycles, power tools, etc.

[0209] When stacking multiple lithium batteries (100, 200) according to an embodiment, a gel-type electrolyte may be placed between the positive electrode and the liquid-impermeable ion-conductive composite membrane. The gel-type electrolyte may include, for example, a VDF-HFP copolymer, a lithium salt, and a solvent.

[0210] FIGS. 4 to 7 are schematic diagrams illustrating a lithium secondary battery according to an embodiment, wherein FIG. 4 is a cylindrical battery, FIG. 5 is a square battery, and FIGS. 6 and 7 are pouch-type batteries. Referring to FIGS. 4 to 7, a lithium battery (1) includes a battery structure (7, electrode assembly) having a separator (4) interposed between a positive electrode (3) and a negative electrode (2), and a case (5) in which the battery structure (7) is built. The positive electrode (3), the negative electrode (2), and the separator (4) may be impregnated with an electrolyte (not shown). The lithium battery (1) may include an assembly (6, sealing member) that seals the case (5) as shown in FIG. 4. In addition, in FIG. 5, the lithium battery (1) may include a positive electrode lead tab (3') and a positive electrode terminal (3"), a negative electrode lead tab (2'), and a negative electrode terminal (2"). As shown in FIGS. 6 and 7, the lithium battery (1) may include electrode tabs (70), i.e., a positive electrode tab (71) and a negative electrode tab (72), which serve as electrical paths for inducing the current formed in the electrode assembly (7) to the outside.

[0211] Referring to FIG. 4, a lithium battery (1) according to one embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). A polymer electrolyte is injected into the battery case (5) and sealed with a cap assembly (6), thereby completing the lithium battery (1). The battery case (5) is cylindrical, but is not necessarily limited to this shape, and may be, for example, square, thin-film, etc.

[0212] For example, a polymer electrolyte including a positive electrode (3), a negative electrode (2), and a separator (4) is wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). A liquid electrolyte is injected into the battery case (5) and sealed with a cap assembly (6), thereby completing a lithium battery (1). The battery case (5) is cylindrical, but is not necessarily limited to this shape, and may be, for example, square, thin-film, etc.

[0213] Referring to FIG. 5, a lithium battery (1) according to an embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound, folded, or laminated to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). A composition for forming a positive electrode electrolyte is injected into the battery case (5), cross-linked, and sealed to complete the lithium battery (1). The battery case (5) is square, but is not necessarily limited to this shape, and may be, for example, cylindrical, thin-film, etc. A positive electrode lead tab (3') and a positive electrode terminal (3") are electrically connected to the positive electrode (3). A negative electrode lead tab (2') and a negative electrode terminal (2") are electrically connected to the negative electrode (2).

[0214] Referring to FIG. 6, a lithium battery (1) according to one embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). A separator (4) is disposed between the positive electrode (3) and the negative electrode (2), and the positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An electrode tab (8) that serves as an electrical path for guiding a current formed in the battery structure (7) to the outside may be included. The above-described polymer electrolyte is injected into the battery case (5) and sealed to complete the lithium battery (1).

[0215] For example, after a polymer electrolyte including a separator (4) is placed between a positive electrode (3) and a negative electrode (2), the positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An electrode tab (8) that serves as an electrical path for guiding the current formed in the battery structure (7) to the outside may be included. A liquid electrolyte may be injected into the battery case (5) and sealed to complete the lithium battery (1). The battery case (5) is not necessarily limited to a square shape, but may be, for example, a cylindrical shape, a thin film shape, etc.

[0216] Referring to FIG. 7, a lithium battery (1) according to an embodiment includes a positive electrode (3), the above-described negative electrode (2), and a separator (4). The above-described polymer electrolyte including the separator (4) is disposed between the positive electrode (3) and the negative electrode (2), thereby forming a battery structure. The battery structure (7) is stacked in a bi-cell structure and then accommodated in a battery case (5). An electrode tab (8) serving as an electrical path for guiding the current formed in the battery structure (7) to the outside may be included. A liquid electrolyte is injected into the battery case (5) and sealed, thereby completing the lithium battery (1). The battery case (5) is not necessarily limited to a square shape, but may be, for example, a cylindrical shape, a thin-film shape, etc.

[0217] A pouch-type lithium battery corresponds to the lithium batteries of FIGS. 4 to 7, each of which uses a pouch as a battery case. The pouch-type lithium battery includes one or more battery structures. A polymer electrolyte is disposed between a positive electrode and a negative electrode to form a battery structure. The battery structures are laminated in a bi-cell structure, then impregnated with a liquid electrolyte, and accommodated and sealed in a pouch to complete the pouch-type lithium battery. For example, although not shown in the drawings, a polymer electrolyte including the above-described positive electrode, negative electrode, and separator may be simply laminated and accommodated in a pouch in the form of an electrode assembly, or may be wound or folded into a jelly-roll-shaped electrode assembly and then accommodated in a pouch. Subsequently, a liquid electrolyte is injected into the pouch and sealed to complete the lithium battery.

[0218] Lithium batteries are used in electric vehicles (EVs) due to their excellent cycle life and high-rate characteristics. For example, they are used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). They are also used in applications requiring large amounts of power storage, such as electric bicycles and power tools.

[0219] Lithium batteries are stacked in multiple layers to form a battery module, and the multiple battery modules form a battery pack. Such a battery pack can be used in any device requiring high capacity and high output. For example, it can be used in laptops, smartphones, electric vehicles, etc. The battery module includes, for example, multiple batteries and a frame that holds them. The battery pack includes, for example, multiple battery modules and a bus bar that connects them. The battery module and / or the battery pack may further include a cooling device. The multiple battery packs are controlled by a battery management system. The battery management system includes a battery pack and a battery control device connected to the battery pack.

[0220] Below, we will look at the definitions of substituents used in chemical formulas.

[0221] The term alkyl, as used in chemical formulas, refers to a fully saturated branched or unbranched (or straight-chain or linear) hydrocarbon.

[0222] Non-limiting examples of the above alkyl include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, neopentyl, iso-amyl, n-hexyl, 3-methylhexyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, and the like.

[0223] At least one hydrogen atom of the above alkyl is selected from the group consisting of a halogen atom, a C1-C20 alkyl group substituted with a halogen atom (e.g., CCF3, CHCF2, CH2F, CCl3, etc.), a C1-C20 alkoxy, a C2-C20 alkoxyalkyl, a hydroxy group, a nitro group, a cyano group, an amino group, an amidino group, a hydrazine, a hydrazone, a carboxyl group or a salt thereof, a sulfonyl group, a sulfamoyl group, a sulfonic acid group or a salt thereof, a phosphoric acid or a salt thereof, or a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C1-C20 heteroalkyl group, a C6-C20 aryl group, a C6-C20 arylalkyl group, a C6-C20 heteroaryl group, a C7-C20 heteroarylalkyl group, It may be substituted with a C6-C20 heteroaryloxy group, a C6-C20 heteroaryloxyalkyl group, or a C6-C20 heteroarylalkyl group.

[0224] The term halogen atoms includes fluorine, bromine, chlorine, iodine, etc.

[0225] The term C1-C20 alkyl group substituted with a halogen atom refers to a C1-C20 alkyl group substituted with one or more halo groups, including, but not limited to, polyhaloalkyl containing monohaloalkyl, dihaloalkyl or perhaloalkyl.

[0226] Monohaloalkyl refers to an alkyl group having one iodine, bromine, chlorine or fluorine, and dihaloalkyl and polyhaloalkyl refer to an alkyl group having two or more identical or different halo atoms.

[0227] The term aryl group used in chemical formulas, used alone or in combination, refers to an aromatic hydrocarbon containing one or more rings.

[0228] The term aryl also includes groups in which an aromatic ring is fused to one or more cycloalkyl rings.

[0229] Non-limiting examples of the above aryl include phenyl, naphthyl, tetrahydronaphthyl, etc.

[0230] Additionally, one or more hydrogen atoms in the above aryl group can be substituted with a substituent similar to that in the case of the above-described alkyl group.

[0231] One or more hydrogen atoms in the above carbon rings can be substituted with a substituent similar to that in the case of the alkyl group described above.

[0232] The following examples and comparative examples are provided for further details. However, the examples are provided for illustrative purposes only and are not intended to be limiting.

[0233] Manufacturing Example 1: Manufacturing of polymer electrolyte

[0234] Trimethylolpropane trimethacrylate (TMPTMA) represented by the following compound 1-1 as a first crosslinking monomer and polyethylene glycol diacrylate (PEG-DA) represented by the following compound 2-1 as a second crosslinking monomer were mixed with tetrahydrofuran as a solvent. Here, the content of THF was 100 parts by weight based on 100 parts by weight of the total weight of trimethylolpropane trimethacrylate (TMPTMA) represented by the following compound 1-1 and polyethylene glycol diacrylate (PEG-DA) represented by the following compound 2-1 as a second crosslinking monomer. And, the mixing ratio of trimethylolpropane trimethacrylate (TMPTMA) represented by the following compound 1-1 and polyethylene glycol diacrylate (PEG-DA) represented by the following compound 2-1 as a second crosslinking monomer was about 7:3 by weight.

[0235] A polymer electrolyte composition was obtained by adding a thermal polymerization initiator to the above mixture. As the thermal polymerization initiator, benzoyl peroxide (BPO), tert-butyl peroxypivalate (t-BPP), or 2,2-azobis-(2-methylpropionitrile) (AIBN, (2,2 -Azobis(2-methylpropionitrile)) was used, and the content of the thermal polymerization initiator was 5 parts by weight based on 100 parts by weight of the total weight of trimethylolpropane trimethacrylate (TMPTMA) represented by the following compound 1-1 and polyethylene glycol diacrylate (PEG-DA) represented by the following compound 2-1 as a second crosslinking monomer.

[0236] In addition to the polymer electrolyte composition, a liquid electrolyte was injected into the battery and sealed, and then thermally crosslinked (in-situ polymerization) was performed, and a polymer electrolyte was obtained by thermal polymerization at 70°C for 2 hours.

[0237] Manufacturing Examples 2 to 5, Comparative Manufacturing Examples 2 to 4, and Comparative Manufacturing Examples 6 to 12

[0238] A polymer electrolyte was prepared in the same manner as in Manufacturing Example 1, except that the types and mixing ratios of the first crosslinking monomer, the second crosslinking monomer, the third crosslinking monomer, the ionic monomer, and the ionic liquid were changed as shown in Table 1 below. 1-butyl-3-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14-TFSI) was used as the ionic liquid.

[0239] Comparative Manufacturing Examples 1 and 5

[0240] Instead of using a solid electrolyte, a liquid electrolyte or PVdF-HFP membrane was prepared as described in Table 1.

[0241] Classification 1 Crosslinking monomer system 2 Crosslinking monomer system 3 Crosslinking monomer Ionic monomer Ionic liquid Mixing ratio (weight ratio) Other Manufacturing example 1 Compound 1-1 Compound 2-1XXX7:3-Manufacturing example 2 Compound 1-1 Compound 2-1X Compound 4-1X7:2:1-Manufacturing example 3 Compound 1-1 Compound 2-1X Compound 4-1X3:3:4-Manufacturing example 4 Compound 1-1 Compound 2-1XXO6:2:2-Manufacturing example 5 Compound 1-1 Compound 2-1 Compound 3-1XX7:2:1-Comparative Manufacturing example 1XXXXX-Use of liquid electrolyte Comparative Manufacturing example 2XXXXO--Comparative Manufacturing example 3X Compound 2-1XXX--Comparative Manufacturing Example 4XX Compound 3-1XX--Comparative Manufacturing Example 5XXXXX-PVdF-HFPmembrane use Comparative Manufacturing Example 6 Compound 1-1XXXX-Comparative Manufacturing Example 7 Compound 1-1XX Compound 4-1X7:3 Comparative Manufacturing Example 8 Compound 1-1XX Compound 4-1X3:7 Comparative Manufacturing Example 9 X Compound 2-1X Compound 4-1X7:3 Comparative Manufacturing Example 10 X Compound 2-1X Compound 4-1X3:7 Comparative Manufacturing Example 11 Compound 1-1X Compound 3-1XX7:3 Comparative Manufacturing Example 12 X Compound 2-1 Compound 3-1XX7:3

[0242]

[0243] Example 1: Manufacturing of lithium metal battery (pouch cell)

[0244] LiNixCoyAlzO2(x+y+z=1, x>0.6), conductive material (Super-P; Timcal Ltd.), binder (PVdF;

[0245] Solvay) and N-methylpyrrolidone were mixed to obtain a cathode composition. The mixing weight ratio of LiNixCoyAlzO2, conductive material, and polymer electrolyte in the cathode composition was 95:3:2.

[0246] The above positive electrode composition was coated on top of aluminum foil (thickness: about 10 μm), dried at 50°C, and the dried resultant was dried in a vacuum at about 120°C to manufacture a positive electrode.

[0247] A separator (PE; 20 μm) was positioned between the positive electrode obtained according to the above process and a copper (Cu) current collector having a thickness of 10 μm, and the liquid electrolyte was injected into the battery along with the solid electrolyte composition prepared in Manufacturing Example 1, sealed, and then thermally crosslinked (in-situ polymerization) was performed, and a lithium metal battery (pouch cell) was manufactured by thermal polymerization at 70°C for 2 hours.

[0248] Examples 2 to 5 and Comparative Examples 1 to 12: Manufacturing of lithium metal batteries (pouch cells)

[0249] A polymer electrolyte was prepared in the same manner as in Manufacturing Example 1, except that the type of polymer electrolyte used was changed as shown in Table 2 below.

[0250] Evaluation Example 1: Confirmation of high-temperature life characteristics

[0251] For lithium metal batteries manufactured according to Examples 1 to 5 and Comparative Examples 1 to 12, constant current charging was performed at 25°C at a current rate of 0.1C until the voltage reached 4.30 V (vs. Li).

[0252] The cell was charged at a constant voltage of 0.05 C while maintaining 4.3 V. After the cell was rested for 10 minutes, it was discharged at a constant current of 0.1 C until the voltage reached 3.6 V (vs. Li) (1st cycle).

[0253] Then, the constant current was charged at a current rate of 0.2C until the voltage reached 4.3V (vs. Li), and the constant voltage was charged until the current reached 0.05C while maintaining 4.3V. After the pouch cell was rested for 10 minutes after charging, it was discharged at a constant current of 0.2C until the voltage reached 3.6V (vs. Li) (2nd cycle) (1st-2nd cycles are the formation stage)

[0254] The pouch cell that had gone through the above-mentioned Mars step was charged at a constant current rate of 0.2 C at 45°C until the voltage reached 4.3 V (vs. Li), and then charged at a constant voltage of 0.05 C while maintaining 4.3 V. After the pouch cell was rested for 10 minutes, the discharge cycle was repeated 100 times, during which the voltage was discharged at a constant current rate of 0.5 C until it reached 3.6 V (vs. Li).

[0255] Here, the capacity retention rate at the 100th cycle is defined by the following equation.

[0256] [ceremony]

[0257] Capacity retention rate [%] = [100 th Discharge capacity in cycles / 1 st Discharge capacity in cycles] Х 100

[0258] The capacity retention rate at the 100th cycle for each high temperature (45℃) is shown in Table 2 below.

[0259] Polymer electrolyte (liquid electrolyte) capacity retention rate (%) Example 1 Manufacturing example 182.1 Example 2 Manufacturing example 284.8 Example 3 Manufacturing example 382.3 Example 4 Manufacturing example 478.0 Example 5 Manufacturing example 579.4 Comparative example 1 Comparative manufacturing example 177.3 Comparative example 2 Comparative manufacturing example 249.6 Comparative example 3 Comparative manufacturing example 377.9 Comparative example 4 Comparative manufacturing example 470.1 Comparative example 5 Comparative manufacturing example 580.5 Comparative example 6 Comparative manufacturing example 681.9 Comparative example 7 Comparative manufacturing example 779.0 Comparative example 8 Comparative manufacturing example 872.1 Comparative example 9 Comparative manufacturing example 976.9 Comparative example 10 Comparative manufacturing example 1068.5 Comparative example 11 Comparative Manufacturing Example 1170.3 Comparative Example 12 Comparative Manufacturing Example 1269.4

[0260] Evaluation Example 2: Thermal Stability Verification - Pouch Cell Heat Exposure Experiment

[0261] The electrolytes used in the manufacturing examples and comparative manufacturing examples were applied to manufacture pouch cells with a capacity of 1 Ah, and then chemical reactions were performed at 0.1 C. After charging to 4.3 V, a temperature sensor (thermocouple) was attached to the cell, and it was placed in an explosion-proof chamber for safety evaluation, and 5 o 150 at a heating rate of C / 1 min o After heating to C, it was maintained at an isothermal temperature for 30 minutes. The change in open circuit voltage (OCV) over time and the occurrence of events (e.g., ignition) were observed, and the results are shown in the table below.

[0262] Polymer electrolyte (liquid electrolyte) Ignition (event) occurrenceIgnition (event) occurrence temperature (℃)Example 1 Manufacturing example 1X-Example 2 Manufacturing example 2X-Example 3 Manufacturing example 3X-Example 4 Manufacturing example 4X-Example 5 Manufacturing example 5X-Comparative example 1 Comparative Manufacturing example 10126 Comparative example 2 Comparative Manufacturing example 2X-Comparative example 3 Comparative Manufacturing example 30133 Comparative example 4 Comparative Manufacturing example 4X-Comparative example 5 Comparative Manufacturing example 50132 Comparative example 6 Comparative Manufacturing example 60131 Comparative example 7 Comparative Manufacturing example 70135 Comparative example 8 Comparative Manufacturing example 8X-Comparative example 9 Comparative Manufacturing example 90134 Comparative example 10 Comparative Manufacturing example 10X-Comparative example 11 Comparative Manufacturing example 11X-Comparative Example 12Comparative Manufacturing Example 12X-

[0263] Referring to Tables 2 and 3, Examples 1 to 5, which include polymer electrolytes according to Manufacturing Examples 1 to 5, respectively, had superior high-temperature capacity retention characteristics and / or thermal stability characteristics compared to Comparative Examples 1 to 12, which include polymer electrolytes according to Comparative Manufacturing Examples 1 to 12, respectively.

[0264] In particular, referring to Tables 2 and 3, unlike Examples 1 to 5, which satisfied both the capacity retention rate characteristic and the non-ignition characteristic, Comparative Examples 1 to 12 could not satisfy all of the above characteristics.

[0265] In addition, referring to Tables 2 and 3, it was confirmed that the solid electrolytes of Examples 1 to 5, which satisfy both the capacity retention characteristics and the non-ignition characteristics, can achieve the effects of the present invention by including both the first cross-linking monomer and the second cross-linking monomer.

[0266] In particular, referring to Examples 2 and 3, it was confirmed that the capacity retention characteristics of the present invention are further enhanced by further including an ionic monomer, and that thermal stability can be secured through crosslinking and densification by the ionic monomer, thereby achieving thermal stability within the battery without deterioration of cell performance.

[0267] In addition, referring to Example 5, it was confirmed that thermal stability can be secured through crosslinking densification by mixing crosslinking agents as the third crosslinking monomer is included, thereby achieving thermal stability within the battery without deterioration of cell performance.

[0268] While the above has been described with reference to drawings and examples, these are merely exemplary, and those skilled in the art will appreciate that various modifications and equivalent implementations are possible. Accordingly, the scope of protection of the present invention should be defined by the appended claims.

[0269] [Explanation of symbols]

[0270] 100, 200: Lithium battery

[0271] 110, 210: cathode assembly 120, 220: electrolyte

[0272] 130, 230: Cathode active material layer 140, 240: Cathode current collector

[0273] 150, 250: anode 225: metal layer

[0274] M: main chain S: side chain

[0275] E: distal end

Claims

1. A repeating unit (A) derived from a first crosslinkable monomer comprising three or more double bond functional groups including an ester bond; and A polymer electrolyte comprising a crosslinked polymer comprising a repeating unit (B) derived from a second crosslinkable monomer comprising two or more double bond functional groups including an ester bond.

2. A polymer electrolyte in the first paragraph, wherein the double bond functional group among the first crosslinking monomer and the second crosslinking monomer independently includes an acrylate group.

3. In the first paragraph, the double bond functional group is a polymer electrolyte represented by the following chemical formula 1: <Chemical Formula 1> In chemical formula 1, R1 is any one selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, * is a bonding site with a neighboring atom.

4. In the first paragraph, the first crosslinking monomer comprises 3 double bond functional groups, A polymer electrolyte wherein the second crosslinking monomer comprises two double bond functional groups.

5. In the first paragraph, the crosslinked polymer, A polymer electrolyte further comprising a repeating unit (C) derived from an ionic monomer comprising an ionic functional group and one double bond functional group.

6. In paragraph 5, A polymer electrolyte wherein the double bond functional group among the above ionic monomers comprises an allyl group, an acrylic group, a vinyl group, or any combination thereof.

7. In paragraph 5, A polymer electrolyte, wherein the ionic functional group contained in the above ionic monomer includes a cationic functional group, an anionic functional group, or a combination thereof.

8. In paragraph 7, A polymer electrolyte wherein the cationic functional group comprises pyrrolidium, piperidinium, ammonium, imidazolium, phosphonium or any combination thereof.

9. In paragraph 7, A polymer electrolyte, wherein the anionic functional group comprises trifluoromethanesulfonyl imide (TFSI), bis(fluorosulfonyl) imide (FSI), acetate, bromide (Br-), chloride (Cl-), iodide (I-), dicyanamide, hexafluorophosphate, tetrafluoroborate, hydrogen sulfate, or any combination thereof.

10. In paragraph 5, A polymer electrolyte wherein the ionic monomer comprises a cationic monomer or a zwitterionic monomer.

11. In paragraph 1, A polymer electrolyte, wherein the weight part of the first crosslinking monomer is 50 to 99 weight parts based on 100 weight parts of the above crosslinked polymer.

12. In the first paragraph, the polymer electrolyte further includes a liquid electrolyte, The above liquid electrolyte is a polymer electrolyte containing an organic solvent or an ionic liquid.

13. In the 12th paragraph, the organic solvent comprises propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether or a mixture thereof. The above ionic liquid contains cations and anions, The above cation includes at least one selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof. A polymer electrolyte comprising at least one anion selected from among BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, BF4-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-.

14. In paragraph 1, The polymer electrolyte further comprises a lithium salt.

15. In paragraph 14, The above lithium salts are LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 A polymer electrolyte comprising SO2)(x and y are each 1 to 20), LiCl, LiI, LiB(C2O4)2, LiBF2(C2O4) or a mixture thereof.

16. A polymer electrolyte according to claim 1, wherein the crosslinked polymer further comprises a repeating unit (D) derived from a third crosslinkable monomer comprising a double bond functional group and a P element.

17. Anode; cathode; and A lithium metal battery comprising a polymer electrolyte according to any one of claims 1 to 17 interposed between the positive electrode and the negative electrode.

18. In paragraph 17, The above negative electrode includes a negative electrode collector, The above negative electrode is a lithium metal battery in which a negative electrode active material layer is absent (free).

19. In paragraph 18, The above negative electrode collector comprises a base film and a metal substrate layer disposed on one or both sides of the base film, The above base film comprises a polymer, and the polymer comprises polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI) or a combination thereof, A lithium metal battery, wherein the metal substrate layer comprises indium (In), copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

20. In paragraph 18, A lithium metal battery further comprising a lithium metal layer disposed between the negative electrode current collector and the polymer electrolyte.

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