A battery comprising a high-concentration electrolyte and a negative electrode having a metal substrate and a protective layer.

Abstract

The present invention relates to a battery comprising a high concentration electrolyte and an anode for the battery comprising a metal substrate and a protective layer disposed directly on at least a portion of the metal substrate, the protective layer comprising a copolymer obtainable by reaction between two or more monomers, a fluoropolymer additive, and a lithium salt. The inventors have demonstrated that the combination of the electrolyte and the anode results in a reduction in the resistance in the battery.

Description

[Technical Field]

[0001] The present invention relates to a battery comprising a negative electrode including a metal substrate and a protective layer directly disposed on at least a portion of the metal substrate, and a high-concentration electrolyte. [Background technology]

[0002] As the development of small, lightweight electronic products, electronic devices, and communication devices progresses rapidly, and the need for electric vehicles to address environmental issues becomes increasingly prominent, there is a growing demand for improved performance in rechargeable batteries used as power sources for these products. Among these, lithium metal rechargeable batteries are attracting attention as high-performance batteries due to their high energy density and high reference electrode potential.

[0003] Due to the high reactivity of lithium metal, side reactions between lithium and the liquid electrolyte occur during battery charging and discharging, thereby accelerating the decomposition of the electrolyte. In addition, for various reasons, electron density non-uniformity can occur on the lithium metal surface during battery operation. As a result, dendritic lithium dendrites are formed on the electrode surface, making the electrode surface very rough and potentially causing separator damage. These side reactions reduce the Coulomb efficiency and / or electrochemical stability of lithium metal batteries, leading to a decrease in the lifespan of lithium batteries.

[0004] Therefore, various attempts are being made to stabilize lithium metal and prevent or reduce side reactions between the electrolyte and lithium metal.

[0005] Korean Patent Application Publication No. 20030042288(A) describes a lithium secondary battery in which dendrite growth on the surface of a lithium metal negative electrode can be suppressed by a crosslinked polymer protective film formed on the surface of a lithium metal, wherein the polymer is crosslinked 1,6-hexanediol diacrylate or a copolymer of 1,6-hexanediol diacrylate and oligoethylene glycol diacrylate. The battery further comprises a gel electrolyte polymer consisting of a mixture of ethylene carbonate, propylene carbonate, and 1 M LiClO4 in poly(vinylidene fluoride-co-hexafluoropropylene).

[0006] U.S. Patent Application Publication No. 2016 / 0372743(A1) relates to a battery having a coating on a lithium metal anode to prevent direct contact between lithium metal and a volatile liquid electrolyte. The coating consists of either a single-layer polymer comprising a PVDF homopolymer, an ionic liquid, and LiFSI, or a double-layer polymer coating having a first outer layer of PVDF, an ionic liquid, and LiFSI, and a second inner layer of poly(styrene-acrylonitrile) and LiFSI. The battery further comprises an electrolyte consisting of 2M LiFSI in ethylene carbonate.

[0007] U.S. Patent No. 6,902,848(B1) discloses a lithium battery comprising a negative electrode stacked with a gel electrolyte and a liquid electrolyte consisting of 1.5 to 6 M LiBF4 in γ-butyrolactone. The gel electrolyte consists of a crosslinked poly(ethylene glycol) acrylate monomer.

[0008] However, a drawback of coating the anode with a protective layer is that it introduces an additional source of resistance within the battery. A polymer-coated anode has increased resistance, particularly increased uncompensated resistance R u and / or increased charge transfer resistance R ct This demonstrates that the increased resistance causes a voltage drop during battery operation, which also consumes some of the useful energy as waste heat.

[0009] Therefore, it is necessary to realize a battery with a protective layer around the negative electrode while minimizing the increase in battery resistance.

[0010] The object of the present invention is to provide a battery that includes a negative electrode having a metal substrate having a protective layer around the metal substrate, in combination with a high-concentration electrolyte. [Overview of the project]

[0011] The objective of the present invention is, a. Negative electrode, Metal substrate and The metal substrate includes a protective layer that is directly placed on at least a portion of it, The protective layer comprises a copolymer and a first lithium salt. The negative electrode and, b. The positive electrode and, c. Electrolyte composition, i. An organic nonfluorinated liquid containing a second lithium salt, ii. Fluorinated liquids and An electrolyte composition containing, This is achieved by providing a battery that includes [a specific component].

[0012] The inventors have surprisingly found that the combination of a protective layer containing a copolymer disposed on a metal substrate of the negative electrode and an electrolyte containing a second lithium salt, an organic non-fluorinated liquid, and a fluorinated liquid reduces the battery resistance, particularly the uncompensated resistance R, as demonstrated in the attached examples. u The decrease in charge transfer resistance R ct We found that this resulted in a decrease in the uncompensated resistance R in the presence of an electrolyte containing a fluorinated liquid such as 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TFTFE). u The decrease in charge transfer resistance R ctThis shows a decrease in [value]. Furthermore, the inventors have surprisingly found that the protective layer according to the present invention functions as a self-healing polymer film, as demonstrated in the attached examples. The protective layer according to the present invention is a mechanically robust polymer that also has self-healing properties, which is the result of a careful balance between polymer chain mobility, the amount of hydrogen bonding motifs, and the degree of crosslinking.

[0013] As those skilled in the art will understand, metallic lithium spontaneously reacts with the electrolyte solvent and salt anions to form a passivation layer known as the solid electrolyte interface (SEI). The SEI layer is inherently heterogeneous in composition, morphology, and ionic conductivity, leading to the formation and growth of dendrites (which leads to safety issues and insufficient battery performance). This SEI layer continues to grow due to its reaction with the liquid electrolyte, resulting in a thick, high-resistance layer. While we do not wish to be bound by any theory, the inventors believe that the protective layer of the present invention on a metal substrate physically separates highly reactive metallic lithium from the electrolyte while maintaining lithium ion conductivity through the film, thereby limiting the formation of the solid electrolyte interface (SEI) layer. Thus, the protective layer prevents the continuous growth of the layer by preventing contact between the electrolyte and the metal substrate, resulting in a thinner SEI layer with lower resistance.

[0014] Self-healing polymers (see, e.g., I. Gadwal, Macromol 2021, 1, 18-36) and high-concentration lithium-based electrolytes diluted with hydrofluoroethers (see, e.g., S. Lin et al., ACS Appl. Mater. Interfaces 2020, 12, 30, 33710-33718) are known in the art, but the inventors have first demonstrated that a combination of a protective layer according to the present invention having self-healing properties and an electrolyte according to the present invention containing a fluorinated liquid results in a battery exhibiting reduced resistance. [Brief explanation of the drawing]

[0015] [Figure 1]SEM (scanning electron microscope) images of each of the three polymer formulations 1-a, 1-b, and 1-c (see Table 1). [Figure 2] Uncompensated resistance (Ru) measured for each Li-Li symmetric coin cell over 20 hours after cell construction, using unprotected lithium anodes and protected anodes using polymer formulations 1-a, 1-b, and 1-c in a 4.5 M LiFSI electrolyte in DME. [Figure 3] Uncompensated resistance (Ru) measured for each Li-Li symmetric coin cell over 20 hours after cell construction, using unprotected lithium anodes and protected anodes using polymer formulations 2-a, 2-b, 2-c, and 2-d in a 4.5 M LiFSI electrolyte in DME. [Figure 4] These are SEM micrographs of polymer films containing varying amounts of HEAA. Each polymer film was cut with a scalpel, imaged, then immersed overnight (16 hours) in 4.5M LiFSI in DME, rinsed with pure DME, and imaged again. [Figure 5] Total specific discharge capacity of Li-NMC pouch cells containing protected anodes with various PEG-to-HEAA ratios (cycling regime was C / 3 to D / 1, and potential was maintained at the top and bottom of the charge). [Figure 6] Coulomb efficiency of Li-NMC pouch cells containing protected anodes with various PEG-to-HEAA ratios (cycle method C / 3 to D / 1, potential held at the top and bottom of the charge). [Figure 7A] (a) Polymer film conductivity in TTE (3:1, v / v) compared to (4.5 M LiFSI in DME) without thermal annealing. (b) Polymer film conductivity in TTE (3:1, v / v) compared to (4.5 M LiFSI in DME) with thermal annealing. [Figure 7B](a) Polymer film conductivity in TTE (3:1, v / v) compared to (4.5 M LiFSI in DME) without thermal annealing. (b) Polymer film conductivity in TTE (3:1, v / v) compared to (4.5 M LiFSI in DME) with thermal annealing. [Figure 8] Total specific discharge capacity of Li-NMC pouch cells containing protected anodes with various PEG-to-HEAA ratios, subjected to thermal annealing (cycle method C / 3 to D / 1, potential held at the top and bottom of the charge). [Figure 9] Coulomb efficiency of Li-NMC pouch cells containing protected anodes with various PEG-to-HEAA ratios, subjected to thermal annealing (cycle method C / 3 to D / 1, potential held at the top and bottom of the charge). [Figure 10] Coulomb efficiency of Li-NMC pouch cells containing a protected anode with electrolytes of various concentrations in the electrolyte composition. [Figure 11A] Coulomb efficiency with respect to temperature of a Li-NMC pouch cell containing a protected anode. [Figure 11B] Coulomb efficiency with respect to temperature of a Li-NMC pouch cell containing a protected anode. [Figure 11C] Coulomb efficiency with respect to temperature of a Li-NMC pouch cell containing a protected anode. [Figure 11D] Coulomb efficiency with respect to temperature of a Li-NMC pouch cell containing a protected anode. [Modes for carrying out the invention]

[0016] To enable the execution of the present invention, preferred embodiments are described in detail in the drawings and in the embodiments for carrying out the invention described below. Although the present invention is described with reference to these particular preferred embodiments, it will be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention includes a number of substitutes, modifications and equivalents, as will become apparent from the following detailed description and the accompanying drawings.

[0017] As used herein and in the claims, the term “comprising” should not be construed as limiting to the means listed thereafter, nor as excluding other elements or processes. It should be interpreted as specifying the presence of the features, integers, processes, or components described as mentioned, but not as excluding the presence or addition of one or more other features, integers, processes, or components, or groups thereof. Accordingly, the expression “composition comprising components A and B” should not be limited to a composition consisting solely of components A and B. It means, with respect to the present invention, that A and B are the only relevant components of the composition. Thus, the terms “comprising” and “including” encompass the more restrictive terms “consisting essentially of” and “consisting of.”

[0018] As used herein, “optional” or “optionally” means that the event or situation described thereafter may or may not occur, and such description includes both the cases in which such event or situation occurs and the cases in which such event or situation does not occur.

[0019] As used herein, the term "alkyl" has the broadest meaning generally understood in the art and may include linear, branched, or combination thereof. In particular, the term "alkyl," alone or in combination, means a linear or branched alkane derivative group, for example, C F~G Alkyl is defined as a linear or branched alkyl group having F to G carbon atoms, for example, C 1~4 Alkyl refers to linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, 1-propyl, 2-propyl (isopropyl), 15-butyl, 2-butyl, 2-methyl-2-propyl (tert-butyl), and 2-methyl-1-propyl (isobutyl).

[0020] The term "alkanediyl", alone or in combination, means a divalent group derived from a linear or branched alkyl.

[0021] As used herein, the term "uncompensated resistance (R u )" is defined as the resistance value including the cell resistance and any minor additional resistance. The main contribution to the cell resistance is, for example, derived from the ionic conductivity of the liquid electrolyte and / or the ionic conductivity of the polymer protective layer. Minor resistance contributions are, for example, metal parts such as cables / connections.

[0022] As used herein, the charge transfer resistance (R ct ) is a measure of the rate of redox reactions occurring in electrochemically active materials (e.g., a limiting process related to the charge transfer process from one atom or compound to another atom or compound, and the rate of electron transfer derived from the electron resistance and ionic resistance at the electrode - electrolyte interface).

[0023] Battery As described above, the first aspect of the present invention is a. A negative electrode (i.e., anode) for a battery, comprising a metal substrate, and a protective layer disposed directly on at least a part of the metal substrate, wherein Formula (I)

[0024]

Chemical formula

[0025] [ka] (In the formula, R 4 =H or CH3, R 5 C 2~6 Alkanediyl is a type of halide, C 1~4 Alkyl, CF3, or OR 6 It is optionally substituted with one or more substituents selected from R 6 is hydrogen or C 1~4 Selected from alkyl groups, X 2 =NH or O, X 3 A copolymer that can be obtained by reaction with a second monomer represented by (=SH, NH2, or OH, where m is an integer selected from 1 to 10, preferably 1 to 5, more preferably m=1), Copolymers in which the weight ratio of the first monomer to the second monomer is 1:5 to 8:1 (w / w), and A protective layer containing a first lithium salt, The negative electrode (i.e., anode) for the battery, b. The positive electrode and, c. Electrolyte composition, i. An organic nonfluorinated liquid containing a second lithium salt, ii. Fluorinated liquids and Includes, An electrolyte composition in which the molar ratio of the second lithium salt to the fluorinated liquid is 1:2 to 1:0.15 (mol / mol), The objective is to provide a battery that includes [the necessary components].

[0026] In a preferred embodiment, the present invention provides a conductive layer comprising a protective layer according to the present invention and a fluoropolymer additive. As will be understood by those skilled in the art, the battery of the present invention is a. Negative electrode, The metal substrate according to the present invention, A conductive layer comprising a protective layer and a fluoropolymer additive according to the present invention The negative electrode includes, b. The positive electrode according to the present invention, c. An electrolyte composition according to the present invention, Includes.

[0027] metal base material One embodiment of the present invention is a negative electrode comprising a metal substrate. In a preferred embodiment, the metal substrate comprises a conductive metal, preferably stainless steel, copper, nickel, iron, cobalt, lithium, lithium alloy, or a combination thereof, more preferably stainless steel, copper, nickel, lithium, lithium alloy, or a combination thereof. In a more preferred embodiment, the metal substrate is a lithium metal substrate or a lithium metal alloy substrate, preferably a lithium metal substrate. As will be understood by those skilled in the art, the metal substrate may be a metal deposited on a support foil such as stainless steel, copper, nickel, iron, or cobalt, or a lithium layer or lithium alloy layer made as a foil or as a layer deposited on a surface.

[0028] Fluoropolymer additives As described above, the conductive layer according to the present invention consists of a protective layer and a fluoropolymer additive according to the present invention, the conductive layer is directly placed on at least a portion of a metal substrate, and the fluoropolymer additive is polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride -Selected from the group consisting of pentafluoropropylene copolymer, propylenetetrafluoroethylene copolymer, ethylenechlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer and combinations thereof, preferably the fluoropolymer additive is polyvinylidene fluoride or poly(vinylidene fluoride-co-hexafluoropropylene), most preferably poly(vinylidene fluoride-co-hexafluoropropylene).

[0029] In preferred embodiments, the fluoropolymer additive is present in an amount of less than 75% by weight, preferably less than 50% by weight, and most preferably less than 20% by weight, based on the total weight of the conductive layer. In preferred embodiments, the fluoropolymer additive is present in an amount of more than 0.05% by weight, preferably more than 5% by weight, and most preferably more than 10% by weight, based on the total weight of the conductive layer. In preferred embodiments, the fluoropolymer additive is present in an amount of 0.05% to 75% by weight, preferably 5% to 50% by weight, and more preferably 10% to 20% by weight, based on the total weight of the conductive layer.

[0030] In preferred embodiments of the present invention, the weight ratio of copolymer to fluoropolymer additive is 1:5 to 8:1 (w / w), preferably 1:2 to 5:1 (w / w), more preferably 1:2 to 4:1, and most preferably 2:1 to 4:1.

[0031] In one embodiment of the present invention, the fluoropolymer additive has a weight-average molecular weight M greater than 1,000 g / mol, preferably greater than 10,000 g / mol, more preferably greater than 100,000 g / mol, and most preferably greater than 300,000 g / mol. w In one embodiment of the present invention, the fluoropolymer additive has a weight-average molecular weight M of less than 1,000,000 g / mol, preferably less than 800,000 g / mol, more preferably less than 750,000 g / mol, and most preferably less than 600,000 g / mol. w In one embodiment of the present invention, the fluoropolymer additive has a weight-average molecular weight M of 1,000 g / mol to 1,000,000 g / mol, preferably 10,000 g / mol to 800,000 g / mol, more preferably 100,000 g / mol to 750,000 g / mol, and most preferably 300,000 g / mol to 600,000 g / mol. w It has. Preferred examples of fluoropolymer additives, particularly poly(vinylidene fluoride-co-hexafluoropropylene), are weight-average molecular weight M of about 400,000 g / mol or about 455,000 g / mol. w It contains fluoropolymer additives such as poly(vinylidene fluoride-co-hexafluoropropylene) which can be commercially purchased from suppliers such as Sigma-Aldrich.

[0032] In one embodiment of the present invention, the fluoropolymer additive has a number average molecular weight M greater than 250 g / mol, preferably greater than 2,500 g / mol, more preferably greater than 25,000 g / mol, and most preferably greater than 75,000 g / mol. nIn one embodiment of the present invention, the fluoropolymer additive has a weight-average molecular weight M of less than 250,000 g / mol, preferably less than 200,000 g / mol, more preferably less than 190,000 g / mol, and most preferably less than 150,000 g / mol. n In one embodiment of the present invention, the fluoropolymer additive has a weight-average molecular weight M of 250 g / mol to 250,000 g / mol, preferably 2,500 g / mol to 400,000 g / mol, more preferably 25,000 g / mol to 190,000 g / mol, and most preferably 75,000 g / mol to 150,000 g / mol. n It has. Preferred examples of fluoropolymer additives, particularly poly(vinylidene fluoride-co-hexafluoropropylene), have a number average molecular weight of about 130,000 g / mol M n Or the number-average molecular weight M of approximately 110,000 g / mol n It contains fluoropolymer additives such as poly(vinylidene fluoride-co-hexafluoropropylene) which can be commercially purchased from suppliers such as Sigma-Aldrich.

[0033] As demonstrated in the attached examples, the inventors have found that the addition of a fluoropolymer additive improves the conductivity of the conductive layer, improves the wettability of the conductive layer, and enables the printing of a homogeneous film of the conductive layer.

[0034] Copolymer One embodiment of the present invention is Equation (I)

[0035] [ka] (In the formula, R 1 =H or CH3, R 2 C 2~6 Alkanediyl is a type of halide, C 1~4 Alkyl, CF3, or OR 3 It is optionally substituted with one or more substituents selected from R 3 is hydrogen or C1~4 Selected from alkyl groups, X 1 A first monomer represented by =NH or O, where n is an integer selected from 5 to 150, preferably 8 to 100, more preferably 10 to 50, Formula (II)

[0036] [ka] (In the formula, R 4 =H or CH3, R 5 C 2~6 Alkanediyl is a type of halide, C 1~4 Alkyl, CF3, or OR 6 It is optionally substituted with one or more substituents selected from R 6 is hydrogen or C 1~4 Selected from alkyl groups, X 2 =NH or O, X 3 This copolymer can be obtained by reaction with a second monomer represented by (=SH, NH2, or OH, where m is an integer selected from 1 to 10, preferably 1 to 5, more preferably m=1).

[0037] One embodiment of the present invention is given by formula (I) (wherein R 1 is H or CH3, preferably H, and R 2 C 2~6 Alkanedil, preferably C 2~4 Alkanediyl, more preferably C2 alkanediyl, where alkanediyl is a halide, C 1~4 Alkyl, CF3, or OR 3 It is optionally substituted with one or more substituents selected from R 3 is hydrogen or C 1~4 Selected from alkyl groups, X 1 A first monomer represented by =NH or O, preferably O, where n is an integer selected from 5 to 150, preferably 8 to 100, more preferably 10 to 50.

[0038] A preferred embodiment of the present invention is a first monomer according to the present invention, the first monomer being of formula (III)

[0039] [ka] (wherein o is an integer selected from 5 to 150, preferably 8 to 100, more preferably 10 to 50). In particular, the first monomer represented by formula (III) is poly(ethylene glycol) diacrylate (PEGDA).

[0040] A preferred embodiment of the present invention is a first monomer according to the present invention, wherein the first monomer has a number average molecular weight M greater than 50 g / mol, preferably greater than 100 g / mol, more preferably greater than 200 g / mol, even more preferably greater than 550 g / mol, and most preferably greater than 700 g / mol. n A preferred embodiment of the present invention is a first monomer according to the present invention, the first monomer having a number average molecular weight M of less than 20,000 g / mol, preferably less than 7,000 g / mol, more preferably less than 4,000 g / mol, even more preferably less than 2,000 g / mol, and most preferably less than 1,000 g / mol. n A preferred embodiment of the present invention is a first monomer according to the present invention, the first monomer having a number average molecular weight M of 50 g / mol to 20,000 g / mol, preferably 100 g / mol to 7,000 g / mol, more preferably 200 g / mol to 4,000 g / mol, even more preferably 550 g / mol to 2,000 g / mol, and most preferably 700 g / mol to 1,000 g / mol. n It has the following characteristics: Specific examples include average M of 250 g / mol, 575 g / mol, 700 g / mol, 4,000 g / mol, or 6,000 g / mol. n A PEGDA having the following characteristics. Preferred examples of the first monomer according to the present invention are number-average molecular weight M of 250 g / mol, 575 g / mol, or 700 g / mol, preferably 700 g / mol. nThis is a PEGDA. PEGDAs can be purchased commercially from suppliers such as Sigma-Aldrich.

[0041] As demonstrated in the following examples, the first monomer according to the present invention, in particular PEGDA, improves the Li-ion conductivity of the copolymer, the protective layer, and / or conductive layer according to the present invention.

[0042] One embodiment of the present invention is a second monomer represented by formula (II), where R 4 =H or CH3, preferably H, R 5 C 2~6 Alkanedil, preferably C 2~4 Alkanediyl, more preferably C2 alkanediyl, where alkanediyl is a halide, C 1~4 Alkyl, CF3, or OR 6 It is optionally substituted with one or more substituents selected from R 6 is hydrogen or C 1~4 Selected from alkyl groups, X 2 =NH or O, preferably NH, X 3 =SH, NH2, or OH, preferably OH, where m is an integer selected from 1 to 10, preferably 1 to 5, most preferably m=1.

[0043] A preferred embodiment of the present invention is a second monomer according to the present invention, the second monomer being of formula (IV)

[0044] [ka] The second monomer, represented by formula (IV) in particular, is N-(2-hydroxyethyl)acrylamide (HEAA). HEAA can be purchased commercially from suppliers such as Sigma-Aldrich and TCI Chemicals.

[0045] As demonstrated in the following examples, the introduction of a second monomer according to the present invention, particularly N-(2-hydroxyethyl)acrylamide (HEAA), into a copolymer yields self-healing properties of the copolymer. The first monomer according to the present invention comprises a hydrogen bond acceptor, for example, a carbonyl functional group of the first monomer represented by formula (I), preferably an ester functional group of the first monomer represented by formula (III). The second monomer according to the present invention comprises a hydrogen bond acceptor, for example, a carbonyl functional group of the second monomer represented by formula (II), preferably an amide functional group of the second monomer represented by formula (IV). The second monomer according to the present invention comprises a hydrogen bond donor, for example, a substituent X of the second monomer represented by formula (II). 3 The hydrogen present in the copolymer is, for example, a thiol, amino, or hydroxyl functional group, preferably the hydrogen of the hydroxyl group of the second monomer represented by formula (IV). The inventors believe that hydrogen bond donors present in the second monomer can form hydrogen bonds with hydrogen bond acceptors present in the further second monomer of the present invention and / or hydrogen bond acceptors present in the first monomer of the present invention. The inventors believe that the hydrogen bonding properties of the copolymer result in the self-healing properties of the copolymer and / or protective layer. The hydrogen bonds present in the copolymer according to the present invention have a relatively weak bond strength (1.9 to 6.9 kcal / mol). -1 ) possesses this, which means they can be destroyed and reformed at ambient temperature.

[0046] As will be understood by those skilled in the art, copolymers according to the present invention can be obtained by a crosslinking step (i.e., radical polymerization) of the corresponding vinyl monomers, for example, the first monomer and the second monomer according to the present invention. In embodiments of the present invention, the initiator that can be used for radical polymerization varies depending on the crosslinking reaction, and all well known photoinitiators or thermal initiators can be used, preferably photoinitiators. Examples of photoinitiators include benzoin, benzoin ethyl ether, benzoin isobutyl ether, alpha-methylbenzoin ethyl ether, benzoin phenyl ether acetophenone, dimethoxyphenyl acetophenone, 2,2-diethoxyacetophenone, 1,1-dichloroacetophenone, trichloroacetophenone, benzophenone, p-chlorobenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-2-methylpropiophenone, benzoylbenzoate, anthraquinone, 2-ethylanthraquinone, 2-chloroanthraquinone, 2-methyl-1-(4-methylthiophenyl)-morpholinopropanone-1,2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocure 1173), and 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (Irgacure Examples of thermal initiators include 907), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (Irgacure 819), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,1-hydroxycyclohexylphenyl ketone (Irgacure 184), Michler ketone, benzyldimethyl ketal, thioxanthone, isopropylthioxanthone, chlorothioxanthone, benzyl disulfide, butanediol, carbazole, fluorenone, alphaacyloxime esters, and combinations thereof. Examples of thermal initiators include the peroxide (-OO-) series, benzoyl peroxide, cumylhydroperoxide, etc., and azo compounds (-N=N-) series, azobisisobutyronitrile, azobisovaleronitrile, etc. may also be used.In preferred embodiments of the present invention, the photoinitiator is phenylbis-(2,4,6-trimethylbenzoyl)-phosphine oxide (Irgacure 819) or 2-methyl-4'-(methylthio)-2-morpholinopropiophenone (Irgacure 907), and is preferably Irgacure 819.

[0047] The initiator content is not particularly limited in the present invention, but is preferably within a range that does not affect the properties of the copolymer, electrodes, and liquid electrolyte present in the battery according to the present invention. In embodiments of the present invention, the initiator is used in a range of 1% to 15% by weight based on the total weight of the conductive layer, preferably in a range of 1% to 5% by weight based on the total weight of the conductive layer, and more preferably in a range of 2% to 4% by weight.

[0048] In embodiments of the present invention, the crosslinking step to give the copolymer according to the present invention is carried out in an organic liquid capable of dissolving the first monomer, the second monomer, and / or the copolymer according to the present invention. Preferably, the organic liquid is a non-aqueous organic liquid. In this case, well-known liquids such as carbonate-based, ester-based, ether-based, ketone-based, alcohol-based, or aprotic liquids may be used as the non-aqueous organic liquid. For example, aprotic organic liquids are selected from the group consisting of N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 1-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl propionate, ethyl propionate, and combinations thereof. Preferred examples of organic liquids are acetonitrile or tetrahydrofuran.

[0049] In embodiments of the present invention, the crosslinking step includes applying heat or irradiating with active energy rays, wherein thermal crosslinking may be performed using a heating method, and the active energy rays may be irradiated with far-infrared rays, ultraviolet rays, or electron beams.

[0050] In embodiments of the present invention, the crosslinking step is carried out by thermal crosslinking or photocrosslinking, preferably by photocrosslinking. In embodiments of the present invention, thermal crosslinking can be carried out at a temperature of 50°C to 200°C, preferably 80°C to 110°C, and the heating time for crosslinking is 30 minutes to 48 hours, more preferably 8 hours to 24 hours. If the heating temperature and time are below the above range, it is difficult to sufficiently form crosslinks, and if the heating temperature and time exceed the above range, side reactions may occur or the material stability may decrease. In preferred embodiments of the present invention, photocrosslinking including irradiation with active energy rays is carried out for 10 seconds to 5 hours, preferably 1 minute to 1 hour, most preferably 2 minutes to 10 minutes. In preferred embodiments of the present invention, photocrosslinking is carried out at a temperature of 5°C to 60°C, preferably 10°C to 50°C, most preferably 20°C to 40°C. If the time of irradiation with active rays is below the above range, it is difficult to sufficiently form crosslinks, and if it exceeds the above range, side reactions may occur or the material stability may decrease.

[0051] As will be understood by those skilled in the art, copolymers can be obtained by the reaction of at least two monomers, a first monomer represented by formula (I) and a second monomer represented by formula (II), but are not limited to reactions between only two different monomers. For example, copolymers can also be obtained by the reaction of three monomers, particularly the first monomer according to the present invention, the second monomer according to the present invention, and a third monomer represented by formula (V) or formula (VI), wherein the third monomer is different from the first and second monomers:

[0052] [ka] (In the formula, R 7 is H or CH3, and R 8 C 2~6 Alkanediyl is a type of halide, C 1~4 Alkyl, CF3, or OR 9 It is optionally substituted with one or more substituents selected from R 9 is hydrogen or C1~4 X selected from alkyl 4 = NH or O, and p is an integer selected from 5 to 150, preferably 8 to 100, more preferably 10 to 50) or

[0053]

Chemical Structure

[0054] A preferred embodiment of the present invention is a copolymer obtainable by the reaction between a maximum of two monomers, and the two monomers are a first monomer represented by formula (I) and a second monomer represented by formula (II).

[0055] A highly preferred embodiment of the present invention is a copolymer obtainable by the reaction between a maximum of two monomers, and the two monomers are a first monomer which is poly(ethylene glycol) diacrylate and a second monomer which is 2-hydroxyethyl acrylamide.

[0056] In a preferred embodiment, the weight ratio of the first monomer to the second monomer is 1 to 5 to 8 to 1, preferably 1 to 3 to 7 to 1, more preferably 1 to 2 to 5 to 1, and most preferably 1 to 2 to 2 to 1.

[0057] In preferred embodiments, the copolymer is present in an amount greater than 20% by weight, preferably greater than 30% by weight, and most preferably greater than 50% by weight, based on the total weight of the conductive layer. In preferred embodiments, the copolymer is present in an amount less than 80% by weight, preferably less than 75% by weight, and most preferably less than 70% by weight, based on the total weight of the conductive layer. In preferred embodiments, the copolymer is present in an amount in the range of 20% to 80% by weight, preferably in the range of 30% to 75% by weight, and more preferably in the range of 50% to 70% by weight, based on the total weight of the conductive layer.

[0058] In preferred embodiments, the copolymer is present in an amount greater than 20% by weight, preferably greater than 30% by weight, and most preferably greater than 35% by weight, based on the total weight of the protective layer. In preferred embodiments, the copolymer is present in an amount less than 80% by weight, preferably less than 75% by weight, and most preferably less than 50% by weight, based on the total weight of the protective layer. In preferred embodiments, the copolymer is present in an amount ranging from 20% to 80% by weight, preferably ranging from 30% to 75% by weight, and more preferably ranging from 35% to 50% by weight, based on the total weight of the protective layer.

[0059] A specific example of the copolymer according to the present invention is formula (VII)

[0060] [ka] (wherein o is an integer selected from 5 to 150, preferably 8 to 100, more preferably 10 to 50, and r, s, and t are integers independently selected from 1 to 10, preferably 2 to 8, most preferably 3 to 6). However, as will be understood by those skilled in the art, the copolymers according to the present invention are not limited to formula (VII) but are shown as exemplary embodiments.

[0061] In a highly preferred embodiment of the present invention, the copolymer according to the present invention, and thus the protective layer and the conductive layer according to the present invention, have self-healing properties, as demonstrated in the following examples.

[0062] In a preferred embodiment of the present invention, the copolymer, protective layer and / or conductive layer according to the present invention are subjected to a thermal annealing process. As understood by those skilled in the art, thermal annealing is a common process used in material chemistry to relieve stress, improve uniformity, and enhance contact with the substrate. In particular, thermal annealing is a process in which the temperature T of a part coated with a coating is first raised from room temperature to a maximum (operating) temperature T max up to, preferably, a temperature T exceeding the recrystallization temperature of the copolymer according to the present invention and / or the protective layer according to the present invention, and then, after the operation (e.g., cutting) is completed, the temperature is lowered back to room temperature. In a highly preferred embodiment, the thermal annealing process is carried out at a temperature in the range of 40 °C to 100 °C, preferably in the range of 50 °C to 90 °C, more preferably in the range of 60 °C to 80 °C, after the UV curing of the copolymer, and / or the duration of thermal annealing is 5 minutes to 10 hours, preferably 15 minutes to 5 hours, most preferably 30 minutes to 90 minutes. In a highly preferred embodiment, the thermal annealing process according to the present invention is carried out in dry air. The inventors have surprisingly found that the thermal annealing process improves the conductivity of the copolymer. In addition, each copolymer subjected to the thermal annealing process appears more homogeneous and has better contact with the Li surface. Furthermore, the inventors have found that after the thermal annealing process, the charge transfer resistance (R ct ) of the negative electrode according to the present invention decreases.

[0063] First lithium salt As described above, the protective layer according to the present invention contains a first lithium salt.

[0064] In one embodiment of the present invention, the first lithium salt is Li2CO3, Li2O, Li2C2O4, LiOH, LiX 7 , ROCO2Li, HCOLi, R 13OLi, Li2O, Li2C2O4, (R 13 OCO2Li)2, (CH2OCO2Li)2, Li2S, LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, LiC(CF3SO2) 3, LiN(SO2C2F5)2, LiN(SO2CF3)2, LiN(SO2F)2, LiSbF6, LiPF3(CF2CF3)3, LiPF3(CF3)3, LiB(C2O4)2 (in the formula, R 13 =Hydroxides and X 7 The first lithium salt is selected from the group consisting of F, Cl, I, or Br and combinations thereof, preferably from the group consisting of LiSCN, LiN(CN)2, LiClO4, Lil, LiBF4, LiAsF6, LiCF3SO3, LiCF3(SO3)2, LiN(SO2C2F5)2, LiN(SO2CF3)2, LiN(SO2F)2, LiSbF6, LiPF3(CF2CF3)3, LiPF3(CF3)3, LiB(C2O4)2 and combinations thereof, more preferably the first lithium salt is LiN(SO2CF3)2 or LiN(SO2F)2, and most preferably the first lithium salt is LiN(SO2F)2.

[0065] In a preferred embodiment of the present invention, the amount of the first lithium salt is greater than 5% by weight based on the total weight of the conductive layer, preferably greater than 10% by weight based on the total weight of the conductive layer, and most preferably greater than 40% by weight based on the total weight of the conductive layer. In a preferred embodiment of the present invention, the amount of the first lithium salt is less than 70% by weight based on the total weight of the conductive layer, preferably less than 65% by weight based on the total weight of the conductive layer, and most preferably less than 60% by weight. In a preferred embodiment of the present invention, the amount of the first lithium salt is 5% to 70% by weight based on the total weight of the conductive layer, preferably 10% to 65% by weight based on the total weight of the conductive layer, and more preferably 40% to 60% by weight.

[0066] In a preferred embodiment of the present invention, the amount of the first lithium salt is greater than 10% by weight based on the total weight of the protective layer, preferably greater than 40% by weight based on the total weight of the protective layer, and most preferably greater than 50% by weight based on the total weight of the protective layer. In a preferred embodiment of the present invention, the amount of lithium salt is less than 70% by weight based on the total weight of the protective layer, preferably less than 65% by weight based on the total weight of the protective layer, and most preferably less than 60% by weight. In a preferred embodiment of the present invention, the amount of lithium salt is 10% to 70% by weight based on the total weight of the protective layer, preferably 40% to 65% by weight based on the total weight of the protective layer, and more preferably 50% to 65% by weight.

[0067] The inventors have found that adding a lithium salt improves the Li ion conductivity of the protective layer and / or conductive layer, preventing the protective layer and / or conductive layer from depleting the lithium ions present in the electrolyte. Furthermore, adding a higher lithium salt content to the protective layer improves the uncompensated resistance R u It decreases.

[0068] protective layer In one embodiment of the present invention, the protective layer has a thickness of 1 μm to 10 μm, preferably 2 μm to 7 μm, and more preferably 3 μm to 6 μm.

[0069] In one embodiment of the present invention, the protective layer is disposed directly on at least a portion of the metal substrate, preferably on the entire surface of the metal substrate. As will be understood by those skilled in the art, the negative electrode according to the present invention includes the protective layer according to the present invention, which forms an outer layer on the metal substrate. In other words, the protective layer is coated on a portion of the surface of the metal substrate, i.e., the protective layer forms a coating on a portion of the surface of the metal substrate, preferably on the entire surface of the metal substrate.

[0070] In preferred embodiments of the present invention, the protective layer according to the present invention has an ionic conductivity greater than 0.01 mS / cm, preferably greater than 0.015 mS / cm, and more preferably greater than 0.05 mS / cm. In preferred embodiments of the present invention, the protective layer has an ionic conductivity less than 0.5 mS / cm, preferably less than 0.2 mS / cm, and more preferably less than 0.1 mS / cm. In preferred embodiments of the present invention, the protective layer according to the present invention has an ionic conductivity in the range of 0.01 mS / cm to 0.5 mS / cm, preferably in the range of 0.015 mS / cm to 0.2 mS / cm, and most preferably in the range of 0.05 mS / cm to 0.1 mS / cm. The ionic conductivity of the protective layer is measured by the uncompensated resistance R in a symmetric Li-Li cell using electronic impedance spectroscopy (EIS). u The ion conductivity is measured by quantification, and is measured after cell construction (meaning, for example, in a battery containing the negative electrode and electrolyte composition according to the present invention).

[0071] A further aspect of the present invention is a method for preparing a protective layer according to the present invention, comprising the following steps: i) A step of adding the first monomer defined above, the second monomer defined above, the initiator defined above, and the first lithium salt defined above to the organic liquid defined above, ii) A step of subjecting the mixture obtained in step i) to the crosslinking step defined above, iii) Optionally, the crosslinked mixture from step ii) is subjected to the thermal annealing step defined above, Includes.

[0072] A further aspect of the present invention is a protective layer that can be obtained by a method for preparing a protective layer according to the present invention.

[0073] conductive layer In one embodiment of the present invention, the conductive layer has a thickness of 1 μm to 10 μm, preferably 2 μm to 7 μm, and more preferably 3 μm to 6 μm.

[0074] In one embodiment of the present invention, the conductive layer is disposed directly on at least a portion of the metal substrate, preferably the conductive layer is disposed directly on the entire surface of the metal substrate. As will be understood by those skilled in the art, the negative electrode according to the present invention includes the conductive layer according to the present invention, the conductive layer forming an outer layer on the metal substrate. In other words, the conductive layer is coated on a portion of the surface of the metal substrate, i.e., the conductive layer forms a coating on a portion of the surface of the metal substrate, preferably on the entire surface of the metal substrate.

[0075] In a preferred embodiment of the present invention, the conductive layer according to the present invention has an ionic conductivity greater than 0.005 mS / cm, preferably greater than 0.01 mS / cm, and more preferably greater than 0.015 mS / cm. In a preferred embodiment of the present invention, the protective layer has an ionic conductivity less than 1.5 mS / cm, preferably less than 1.2 mS / cm, and more preferably less than 1 mS / cm. In a preferred embodiment of the present invention, the conductive layer according to the present invention has an ionic conductivity in the range of 0.005 mS / cm to 1.5 mS / cm, preferably in the range of 0.01 mS / cm to 1.2 mS / cm, and most preferably in the range of 0.015 mS / cm to 1 mS / cm. The ionic conductivity of the protective layer is measured by the uncompensated resistance R measured by electron impedance spectroscopy (EIS) in a symmetric Li-Li cell. u The ion conductivity is measured by quantification, and is measured after cell construction (meaning, for example, in a battery containing the negative electrode and electrolyte composition according to the present invention).

[0076] A further aspect of the present invention is a method for preparing a conductive layer according to the present invention, comprising the following steps: i) A step of adding the first monomer defined above, the second monomer defined above, the initiator defined above, the lithium salt defined above, and the fluoropolymer additive defined above to the organic liquid defined above, ii) A step of subjecting the mixture obtained in step i) to the crosslinking step defined above, iii) Optionally, the crosslinked mixture from step ii) is subjected to the thermal annealing step defined above, Includes.

[0077] A further aspect of the present invention is a conductive layer that can be obtained by a method for preparing a conductive layer according to the present invention.

[0078] negative electrode A further aspect of the present invention is the negative electrode according to the present invention, a. Metal base material, b. A protective layer that can be obtained by a method for preparing a protective layer according to the present invention, which is directly disposed on at least a portion of a metal substrate, and / or a conductive layer that can be obtained by a method for preparing a conductive layer according to the present invention, which is directly disposed on at least a portion of a metal substrate. Includes.

[0079] Further aspects of the present invention include the following steps: i) A step of adding the first monomer defined above, the second monomer defined above, the initiator defined above, the lithium salt defined above, and optionally the fluoropolymer additive defined above, to the organic liquid defined above. ii) A step of coating at least a portion of a metal substrate, preferably the entire surface of the metal substrate, with the mixture obtained in step i), iii) A step of subjecting the coated metal substrate from step ii) to the crosslinking step defined above, iv) Optionally, the crosslinked coated metal substrate from step iii) is subjected to the thermal annealing process defined above, This is a method for preparing a negative electrode for a battery, including [the specified component].

[0080] In one embodiment of the present invention, the amount of solid (i.e., the sum of the first monomer, the second monomer, the initiator, the lithium salt, and the fluoropolymer additive) is greater than 1% by weight, preferably greater than 2% by weight, and most preferably greater than 3% by weight, based on the total weight of the solid and liquid. In one embodiment of the present invention, the amount of solid (i.e., the sum of the first monomer, the second monomer, the initiator, the lithium salt, and the fluoropolymer additive) is less than 10% by weight, preferably less than 8% by weight, and most preferably less than 5% by weight, based on the total weight of the solid and liquid. In one embodiment of the present invention, the amount of solid (i.e., the sum of the first monomer, the second monomer, the initiator, the lithium salt, and the fluoropolymer additive) is 1% to 10% by weight, preferably 2% to 8% by weight, and most preferably 3% to 5% by weight, based on the total weight of the solid and liquid.

[0081] The coating process may be carried out using methods used in conventional wet processes as understood by those skilled in the art, such as spin coating, spray coating, doctor blade coating, and dip coating.

[0082] Optionally, a drying step is performed after the coating step. The drying step is performed at a temperature above the boiling point of the organic liquid and at a temperature equal to the glass transition temperature T of the copolymer and / or protective layer according to the present invention. g The following temperatures may be used to perform the process appropriately. The drying process may also be performed to remove any remaining liquid from the surface of the metal substrate and, at the same time, to improve the adhesion of the copolymer and / or protective layer according to the present invention.

[0083] A further aspect of the present invention is a negative electrode that can be obtained by a method for preparing a negative electrode for a battery according to the present invention.

[0084] battery Further embodiments of the present invention include: a. A negative electrode according to the present invention, or a negative electrode that can be obtained by a method for preparing a negative electrode for a battery according to the present invention, b. The positive electrode and, c. Preferably an electrolyte composition disposed between the positive and negative electrodes, d. Optionally, a separator and, It is a battery that includes [something].

[0085] In a preferred embodiment of the present invention, the battery is a lithium metal battery, preferably a lithium metal secondary battery.

[0086] positive electrode The material for the positive electrode (i.e., cathode) is not particularly limited, and examples include transition metal compounds or specialized metal compounds having a structure that can diffuse lithium ions, and lithium oxides. In particular, examples include LiCoO2, LiNiO2, LiMnO4, and LiFePO4. Preferred positive electrode materials are mixed metal oxides containing lithium, nickel, and optionally manganese, cobalt, and / or aluminum.

[0087] In a preferred embodiment of the present invention, the positive electrode comprises a positive electrode material selected from the group consisting of lithium nickel-manganese-cobalt oxide, lithium nickel-manganese oxide, lithium nickel-cobalt-aluminum oxide, lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt iron phosphate, lithium sulfide, sulfur, and aluminum, and preferably the positive electrode material is lithium nickel-manganese-cobalt oxide or lithium nickel-cobalt-aluminum oxide.

[0088] The positive electrode can be formed by press-molding the positive electrode material listed above together with a known conductive additive or binder, or by press-molding the positive electrode active material together with a known conductive additive or binder, in an organic liquid such as pyrrolidone. This can be obtained by applying the mixture, coating it onto a current collector such as aluminum foil, and then drying it.

[0089] electrolyte composition In one embodiment of the present invention, the battery comprises an electrolyte composition, preferably a liquid electrolyte composition. In a preferred embodiment, the electrolyte composition is placed between the positive electrode and the negative electrode.

[0090] In one embodiment of the present invention, the electrolyte composition is i. An organic nonfluorinated liquid containing a second lithium salt, ii. Fluorinated liquids and, Includes.

[0091] In preferred embodiments of the present invention, the organic nonfluorinated liquid is N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, allyl ether, diethylene glycol dimethyl ether (diglym), triethylene glycol dimethyl ether (triglyceride), tetraethylene glycol dimethyl ether (tetraglyceride), butyldiglym, polyethylene glycol, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, methyl methoxymethane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidone, methyl propionate, propion The non-fluorinated organic liquid is selected from the group consisting of ethyl acid, 1,4-dioxane, trimethyl phosphate (TMPa), triethyl phosphate (TEPa), dimethylmethylphosphonate (DMMP), hexamethyldisiloxane, hexamethylcyclotrisiloxane, and combinations thereof, and preferably the non-fluorinated organic liquid is selected from the group consisting of 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran, allyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, butyl diglyme, dimethyl ether, diethyl ether, polyethylene glycol, acetonitrile, dimethyl sulfoxide, sulfolane, trimethyl phosphate, triethyl phosphate, dimethylmethylphosphonate, hexamethyldisiloxane, hexamethylcyclotrisiloxane, 1,2-dimethoxymethane, or 1,2-diethoxyethane, and most preferably the non-fluorinated organic liquid is 1,2-dimethoxymethane or 1,2-dimethoxyethane.

[0092] In a preferred embodiment of the present invention, the second lithium salt is Li2CO3, Li2O, Li2C2O4, LiOH, LiX 8 , R14 OCO2Li, HCOLi, R 14 OLi, Li2O, Li2C2O4, (R 14 OCO2Li)2, (CH2OCO2Li)2, Li2S, LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, LiC(CF3SO2) 3, LiN(SO2C2F5)2, LiN(SO2CF3)2, LiN(SO2F)2, LiSbF6, LiPF3(CF2CF3)3, LiPF3(CF3)3, LiB(C2O4)2 (in the formula, R 14 =Hydroxides and X 8 =F, Cl, I or Br), preferably selected from the group consisting of LiSCN, LiN(CN)2, LiClO4, LiI, LiBF4, LiAsF6, LiCF3SO3, LiCF3(SO3)2, LiN(SO2C2F5)2, LiN(SO2CF3)2, LiN(SO2F)2, LiSbF6, LiPF3(CF2CF3)3, LiPF3(CF3)3, LiB(C2O4)2 and combinations thereof, more preferably the lithium salt is LiN(SO2CF3)2 or LiN(SO2F)2, and most preferably the lithium salt is LiN(SO2F)2.

[0093] In a very preferred embodiment, the first lithium salt and the second lithium salt described above are the same lithium compound.

[0094] In a preferred embodiment of the present invention, the concentration of the second lithium salt in the organic nonfluorinated liquid is greater than 1 M, preferably greater than 2 M, and most preferably greater than 3 M. In a preferred embodiment of the present invention, the concentration of the second lithium salt in the organic nonfluorinated liquid is less than 10 M, preferably less than 8 M, and most preferably less than 6 M. In a preferred embodiment of the present invention, the concentration of the second lithium salt in the organic nonfluorinated liquid is in the range of 1 M to 10 M, preferably in the range of 2 M to 8 M, and most preferably in the range of 3 M to 6 M.

[0095] In one embodiment, the fluorinated liquid is a fluorinated ether, a fluorinated carbonate, or a fluorinated aromatic compound. In a preferred embodiment, the fluorinated liquid is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TFTFE), tris(2,2,2-trifluoroethyl) orthoformate (TFEO), methoxynononafluorobutane (MOFB), ethoxynononafluorobutane (EOFB), di(2,2,2-trifluoroethyl) carbonate (DTFEC), tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tris(hexafluoroisopropyl) orthoformate (THFiPO), tris(2,2-difluoroethyl) orthoformate (T The fluorinated liquid is selected from the group consisting of DFEO), bis(2,2,2-trifluoroethyl)methyl orthoformate (BTFEMO), tris(2,2,3,3,3-pentafluoropropyl) orthoformate (TPFPO), tris(2,2,3,3-tetrafluoropropyl) orthoformate (TTPO), and combinations thereof. Preferably, the fluorinated liquid is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), or 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TFTFE), and most preferably 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE).

[0096] In preferred embodiments, the molar ratio of the second lithium salt to the organic nonfluorinated liquid is 1:3 to 1:0.5 (mol / mol), preferably 1:2 to 1:0.60 (mol / mol), more preferably 1:1.60 to 1:0.80 (mol / mol), and most preferably 1:1.50 to 1:10.

[0097] In preferred embodiments, the molar ratio of the second lithium salt to the organic nonfluorinated liquid is 1:2 to 1:0.15 (mol / mol), preferably 1:1.85 to 1:0.25 (mol / mol), more preferably 1:1.70 to 1:0.35 (mol / mol), even more preferably 1:1.50 to 1:0.35 (mol / mol), and most preferably 1:1 to 1:0.40 (mol / mol).

[0098] In preferred embodiments, the molar ratio of the organic non-fluorinated liquid to the fluorinated liquid is 1:2 to 1:0.10 (mol / mol), preferably 1:1.50 to 1:0.20 (mol / mol), more preferably 1:1.20 to 1:0.25 (mol / mol), even more preferably 1:1 to 1:0.30 (mol / mol), and most preferably 1:0.85 to 1:0.30 (mol / mol).

[0099] In preferred embodiments of the present invention, the volume ratio of the organic non-fluorinated liquid to the fluorinated liquid is 6:1 to 1:2 (vol / vol), preferably 5:1 to 1:1 (vol / vol), and most preferably 4:1 to 2:1 (vol / vol).

[0100] As will be understood by those skilled in the art, the organic liquid according to the present invention is a liquid used in a crosslinking process to give a copolymer according to the present invention, while the organic nonfluorinated liquid according to the present invention is a liquid present in the electrolyte composition according to the present invention.

[0101] As will be understood by those skilled in the art, the fluorinated liquid according to the present invention contains at least one fluoride substituent, while the organic nonfluorinated liquid does not have a fluoride substituent.

[0102] Separator To prevent short circuits between the positive and negative electrodes, a separator is usually inserted between the cathode and anode. While the material and shape of the separator are not particularly limited, it is preferable that it allows the electrolyte composition to pass through easily and that the separator is an insulator and chemically stable. Examples include microporous films and sheets made from various polymer materials. Specific examples of polymer materials include polyolefin polymers, nitrocellulose, polyacrylonitrile, polyvinylidene fluoride, polyethylene, and polypropylene. From the viewpoint of electrochemical and chemical stability, polyolefin polymers are preferred.

[0103] others In a preferred embodiment of the present invention, the battery of the present invention has a Coulomb efficiency of at least 93%, preferably at least 94%, more preferably at least 95%, even more preferably at least 96%, even more preferably at least 97%, and most preferably at least 98%. The Coulomb efficiency is evaluated using the following general formula:

[0104]

number

[0105] use A further aspect of the present invention is the uncompensated resistance R of the battery. u The objective is to provide a battery usage according to the present invention that reduces [a certain value].

[0106] A further aspect of the present invention is the charge transfer resistance R of the battery. ct The objective is to provide a battery usage according to the present invention that reduces [a certain value]. [Examples]

[0107] The present invention is further illustrated in the following embodiments.

[0108] Description of cell preparations and test methods All tested coin cells were of the CR2032 type. Cells were prepared by stacking the positive electrode casing, positive electrode (pre-immersed in electrolyte), Cellguard separator, 50 μL electrolyte droplet, negative electrode, spacer, corrugated spring, and negative electrode casing in that order. A manual welding machine manufactured by MTI was used to press the cells at 80 kg / cm². 2 The welding was performed using pressure.

[0109] Li-Li pouch cells were prepared according to the following specifications: Format = 1 Li (58 × 58 mm) / 1 Sep (62 × 62 mm) / 1 Li (50 × 50 mm), "Nominal Capacity" = 0.1 Ah, Separator = Alumina-coated Targray SH220W22, Lithium = 100 μm thickness (coated or uncoated), Electrolyte Loading = 3.00 μL mAh -1 (i.e., 0.3 mL), C rate = C / 5 D / 5 (standard regime) or C / 3 D / 1, with potential retention (new regime), cycle temperature = 25°C.

[0110] Li-NMC pouch cells were prepared according to the following specifications: Format = 3Li (58×58mm) / 4Sep (62×62mm) / 2NMC (56×54mm), Nominal capacity = 0.48Ah (cathode surface capacity of 4mAh cm²). -2 (Assuming the above), separator = Targray SH220W22 coated with alumina, lithium = 100 μm thick, electrolyte addition amount = 2.00 μL mAh -1 (i.e., 0.97 mL) or 1.75 μL mAh -1 That is, 0.85 mL), C rate = C / 5 D / 5 (standard regime) or C / 3 D / 1, with potential retention (new regime), cycle temperature = 25°C. The NMC cathode uses LiNi as the positive electrode active material. 0.6 Mn 0.2 Co 0.2 Contains O2, carbon black, and PVDF in a weight ratio of 92:4:4.

[0111] Uncompensated resistance R uThis is measured by electrochemical impedance spectroscopy (Nyquist diagram) of Li-Li symmetric coin cells containing lithium metal anodes coated or uncoated with a protective layer. In the tests, frequencies from 1 MHz to 1 Hz were applied.

[0112] Charge transfer resistance R ct This is measured by electrochemical impedance spectroscopy (Nyquist diagram) of Li-Li symmetric coin cells containing lithium metal anodes coated or uncoated with a protective layer. In the tests, frequencies from 1 MHz to 1 Hz were applied.

[0113] The ionic conductivity of the protective layer is determined by the uncompensated resistance R in a symmetric Li-Li cell using electron impedance spectroscopy (EIS). u The quantification of the coefficients is used for measurement, and ionic conductivity is measured after cell construction.

[0114] The cross-section of the protective layer was analyzed using a scanning electron microscope (SEM). A JEOL benchtop SEM was used (samples were imaged under vacuum within the SEM, secondary electron imaging, probe current set to standard, SEM column acceleration voltage).

[0115] Polymer-protected anodes are prepared by adding monomers, lithium salts, initiators, and fluoropolymer additives to an organic liquid in the amounts shown in the table below. These mixtures are coated onto the anode and subjected to UV curing for 5 minutes using Irgacure 819 as a photoinitiator. Optionally, thermal annealing of the polymer is performed after UV curing the polymer-protected anode at 70°C for 1 hour.

[0116] Example 1 To evaluate the effect of the amount of fluoropolymer additive, the following polymer formulations 1-a, 1-b, and 1-c were prepared (see Table 1, PEGDA = 700 g / mol M nPoly(ethylene glycol) diacrylate, LiTFSI=LiN(SO2CF3)2, PVDF-HFP=poly(vinylidene fluoride-co-hexafluoropropylene), THF=tetrahydrofuran).

[0117] [Table 1]

[0118] Figure 1 shows the effect of a decrease in the weight percentage of fluoropolymer additives in the polymer formulation on film continuity. While formulations 1-a and 1-b form homogeneous films on the lithium substrate, excessively reducing the amount of PVDF-HFP (9:1, formulation 1-c) results in a much lower uncompensated resistance (R u Figure 2 illustrates the discontinuous and patchy film that results from the formation of a film exhibiting the following characteristics. Figure 2 demonstrates the effect on conductivity, showing that the optimal PEG to PVDF-HFP ratio is 3:1, providing a continuous polymer film, and R is obtained when compared with formulation 1-a. u It is decreasing.

[0119] Example 2 To evaluate the effect of lithium salts, the following polymer formulations 2-a, 2-b, 2-c, and 2-d were prepared (see Table 2, PEGDA = 700 g / mol M n Poly(ethylene glycol) diacrylate, LiTFSI=LiN(SO2CF3)2, LiFSI=LiN(SO2F)2, PVDF-HFP=poly(vinylidene fluoride-co-hexafluoropropylene), THF=tetrahydrofuran).

[0120] [Table 2]

[0121] The conductivity data from each of the polymer formulations in Table 2 are shown in Figure 3. The problem with the low film salt content (10 wt%) in the polymer formulations is clear because, over the first 20 hours, the resistance of the Li-Li coin cell increases as the resistant polymer formulation absorbs salt from the electrolyte. u This is because the R of each cell decreases, and this process should be prevented. Increasing the salt content of the polymer formulation from 10% by weight to 50% by weight of the total weight of the formulation results in improved conductivity of the polymer film in each example. u This results in a decrease in (compounds 2-b and 2-d exhibit similar uncompensated resistances of approximately 45-47 Ω). The R of a film containing 50 wt% salt for 0-60 hours is also measured. u The stability indicates that ion movement between the polymer membrane and the electrolyte is in equilibrium from the cell construction, and that depletion of electrolyte salts is avoided.

[0122] Example 3 To evaluate the effect of N-hydroethylacrylamide monomer, the following polymer formulations 4-a, 4-b, 4-c, and 4-d were prepared (see Table 3, PEGDA = 700 g / mol). n Poly(ethylene glycol) diacrylate, HEAA = N-hydroxyethylacrylamide, PVDF-HFP = poly(vinylidene fluoride-co-hexafluoropropylene), THF = tetrahydrofuran).

[0123] [Table 3]

[0124] A protective layer of each formulation was coated onto a lithium substrate, cured, and then cut by drawing a scalpel across the coated surface. The cut samples were imaged by SEM, and then immersed overnight (16 hours) in 4.5 M LiFSI in 1,2-dimethoxyethane (DME). The films were rinsed with pure DME to remove excess LiFSI salts, allowing for clearer SEM micrographs, then dried and observed under SEM. The results for each of the polymer formulations in Table 3 are shown in Figure 4.

[0125] As expected, formulation 4-a (0 wt% HEAA) (1:0) does not exhibit self-healing properties due to the absence of hydrogen bond donors. Protectants containing the minimum amount of HEAA (formulation 4-b) also show no evidence of self-healing under these conditions. Increasing the HEAA content to a PEGDA to HEAA weight ratio of 3:1 results in the polymer film resealing at the created incision site. Finally, formulation 4-d (PEGDA to HEAA weight ratio 1:1 w / w) also exhibits substantial self-healing properties (see Figure 4). In addition, it is noteworthy that formulation 4-d appears to have better adhesion to the Li metal surface when observed under SEM compared to the other formulations.

[0126] Next, each polymer formulation was tested in a Li-NMC cell against a reference cell (without polymer). 1.75 μL mAh -1 Cells containing the following additive amounts (4.5 M LiFSI in DME) versus TTE (3:1, vol / vol, TTE = 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether) were cycled in a C / 3 to D / 1 cycle using foam (80 × 80 mm) under a fixed volume pressure of 0.06 MPa. Each polymer-protected cell functioned similarly to the reference cell (see Figures 5 and 6).

[0127] In the next step, the conductivity of each polymer formulation was evaluated before and after thermal annealing (1 hour at 70°C in dry air). The results are shown in Figures 7(a) and 7(b), respectively. Clearly, thermal annealing improves the conductivity of the polymer film. Approximately 0.1 mS cm -1 Increasing the film conductivity to the minimum threshold is considered essential for successful anode protection. Higher conductivity results in a lower energy barrier to the plating beneath the polymer film, which helps reduce dendrite penetration, decrease the amount of dead lithium, and extend the functionality of the electrolyte and lithium anode. It was also observed that each polymer formulation appeared more homogeneous and had better contact with the lithium surface.

[0128] Next, each polymer formulation after annealing was tested in a Li-NMC cell against a reference cell (without polymer). 1.75 μL mAh -1 Cells containing an additive ratio of (4.5 M LiFSI in DME) to TTE (3:1, vol / vol, TTE = 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether) were cycled in a C / 3 to D / 1 cycle using foam (80 × 80 mm) under a fixed volume pressure of 0.06 MPa. Each heat-annealed polymer-protected cell performed similarly and was up to 20% better than the reference cell (see Figures 8 and 9).

[0129] Example 4 A systematic screening of electrolytes was performed, and a 5.23 M LiFSI solution in DME (LiFSI to DME molar ratio = 1:1) was diluted with TTE in various volume ratios. Pouch cells were tested at 25°C in a voltage window of 3.0 V to 4.3 V using a standard C / 5 to D / 5 method, including initial cycles at slower rates of C / 10 to D / 10. The electrolyte ratio was 2 μL mAh -1The values ​​were maintained at the specified values. As shown in Figure 10, the absence of TTE (5.23 M LiFSI in DME) or the addition of large amounts of TTE ((5.23 M LiFSI in DME) vs. TTE 1:2 vol / vol) resulted in reduced cycle lifetime compared to other dilutions ((5.23 M LiFSI in DME) vs. TTE 3:1, 2:1, and 1:1 vol / vol). The incomplete results for ((5.23 M LiFSI in DME) vs. TTE 3:1 vol / vol) were attributed to poor cell construction.

[0130] Example 5 Charge transfer resistance R for lithium metal substrates that are not coated with polymer (bare Li) or lithium metal substrates coated with formulations 4-a, 4-b, and 4-c ct and uncompensated resistor R u This was measured and evaluated at different cycle temperatures (see Figure 11). In the presence of 4.5 M LiFSI in DME containing TTE ((4.5 M LiFSI in DME) vs. TTE 3:1 v / v), polymer films containing more HEAA in the main chain had a higher charge transfer resistance R compared to anodes protected with polymers where TTE was absent in the electrolyte composition. ct The decrease and uncompensated resistance R u It shows a decrease.

Claims

1. a. The negative electrode, Metal substrate and A protective layer disposed directly on at least a portion of the aforementioned metal substrate, Equation (I) 【Chemistry 1】 (wherein R １ = H or CH ３ and R ２ is C ２～６ alkanediyl, and the alkanediyl is optionally substituted with one or more substituents selected from halides, C １～４ alkyl, CF ３ or OR ３ and R ３ is selected from hydrogen or C １～４ alkyl, X １ = NH or O, and n is an integer selected from 5 to 150) and a first monomer represented by Formula (II) 【Chemistry 2】 (In the formula, R ４ = H or CH ３ And R ５ C ２～６ It is an alkanediyl, and the alkanediyl is a halide, C １～４ Alkyl, CF ３ OR ６ It is optionally substituted with one or more substituents selected from R ６ is hydrogen or C １～４ Selected from alkyl groups, X ２ = NH or O, X ３ =SH,NH ２ A copolymer that can be obtained by reaction between a first monomer and a second monomer represented by (or OH, where m is an integer selected from 1 to 10), wherein the weight ratio of the first monomer to the second monomer is 1:20 to 20:1 (w / w), and A protective layer containing a first lithium salt and The negative electrode includes, b. The positive electrode and, c. An electrolyte composition, i. An organic nonfluorinated liquid containing a second lithium salt, ii. Fluorinated liquids and Includes, The molar ratio of the second lithium salt to the organic nonfluorinated liquid is 1:3 to 1:0.5 (mol / mol), The molar ratio of the second lithium salt to the fluorinated liquid is 1:2 to 1:0.15 (mol / mol). Electrolyte composition and Lithium metal batteries, including those containing lithium metal.

2. The lithium metal battery according to claim 1, wherein the molar ratio of the organic non-fluorinated liquid to the fluorinated liquid is 1:2 to 1:0.10 (mol / mol).

3. The lithium metal battery according to claim 1, wherein the negative electrode comprises a conductive layer comprising a protective layer according to claim 1 and a fluoropolymer additive, and the fluoropolymer additive is selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene tetrafluoroethylene copolymer, ethylene chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, and combinations thereof.

4. The lithium metal battery according to claim 3, wherein the weight ratio of the copolymer to the fluoropolymer additive is 1:10 to 10:1 (w / w).

5. The first lithium salt is Li ２ CO ３ Li ２ O, Li ２ C ２ O ４ LiOH, LiX ７ , R １３ OCO ２ Li, HCOLi, R １３ OLi, Li ２ O, Li ２ C ２ O ４ (ROCO ２ Li) ２ , (CH ２ OCO ２ Li) ２ Li ２ S, LiSCN, LiN(CN) ２ LiClO ４ LiBF ４ LiAsF ６ LiPF ６ LiCF ３ SO ３ LiC (CF ３ SO ２ ) ３ , LiN (SO ２ C ２ F ５ ) ２ , LiN (SO ２ CF ３ ) ２ , LiN (SO ２ F) ２ LiSbF ６ LiPF ３ (CF ２ CF ３ ) ３ LiPF ３ (CF ３ ) ３ LiB(C) ２ O ４ ) ２ (In the formula, R １３ = Hydrocarbons and X ７ A lithium metal battery according to claim 1, selected from the group consisting of F, Cl, I, or Br and combinations thereof.

6. The first monomer is of formula (III) 【Transformation 3】 A lithium metal battery according to claim 1, represented by (wherein o is an integer selected from 5 to 150).

7. The second monomer is of formula (IV) 【Chemistry 4】 A lithium metal battery according to claim 1, represented by [the specified figure].

8. The lithium metal battery according to claim 1, wherein the weight ratio of the first monomer to the second monomer is 1:10 to 14:1 (w / w).

9. The lithium metal battery according to claim 1, wherein the copolymer is obtained by the reaction of the first monomer and the second monomer using a photoinitiator.

10. The lithium metal battery according to claim 1, wherein the protective layer has an ionic conductivity in the range of 0.05 mS / cm to 0.1 mS / cm.

11. where the second lithium salt is Li ２ CO ３ Li ２ O ２ C ２ O ４ LiOH, LiX ８ R １４ OCO ２ Li, HCOL １４ Li ２ O ２ C ２ O ４ (ROCO ２ Li) ２ (CH ２ OCO ２ Li) ２ Li ２ S, LiSCN, LiN(CN) ２ LiClO ４ LiBF ４ LiAsF ６ LiPF ６ LiCF ３ SO ３ LiC(CF ３ SO ２ ) ３ LiN(SO ２ C ２ F ５ ) ２ LiN(SO ２ CF ３ ) ２ LiN(SO ２ F) ２ LiSbF ６ LiPF ３ (CF ２ CF ３ ) ３ LiPF ３ (CF ３ ) ３ LiB(C ２ O ４ ) ２ (where R １４ = hydrocarbon and X ８ = F, Cl, I or Br), and the lithium metal battery according to claim 1, selected from the group consisting of these combinations.

12. The aforementioned organic non-fluorinated liquid is N-methyl-2-pyrrolidone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, 4-methyl-1,3-dioxene, diethyl ether, allyl ether, diethylene glycol dimethyl ether (diglym), triethylene glycol dimethyl ether (trilym), tetraethylene glycol dimethyl ether ( A lithium metal battery according to claim 1, selected from the group consisting of tetraglyceride, butyldiglyme, polyethylene glycol, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, tyl methoxymethane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidone, methyl propionate, ethyl propionate, 1,4-dioxane, trimethyl phosphate (TMPa), triethyl phosphate (TEPa), dimethylmethylphosphonate (DMMP), hexamethyldisiloxane, hexamethylcyclotrisiloxane, and combinations thereof.

13. The fluorinated liquid is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), bis(2,2,2-trifluoroethyl) ether (BTFE), 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether (TFTFE), tris(2,2,2-trifluoroethyl) orthoformate (TFEO), methoxynonanafluorobutane (MOFB), ethoxynonanafluorobutane (EOFB), di(2,2,2-trifluoroethyl) carbonate (DTFEC), tris(2,2,2- A lithium metal battery according to claim 1, selected from the group consisting of difluoroethyl orthoformate (TFEO), tris(hexafluoroisopropyl) orthoformate (THFiPO), tris(2,2-difluoroethyl) orthoformate (TDFEO), bis(2,2,2-trifluoroethyl)methyl orthoformate (BTFEMO), tris(2,2,3,3,3-pentafluoropropyl) orthoformate (TPFPO), tris(2,2,3,3-tetrafluoropropyl) orthoformate (TTPO), and combinations thereof.

14. The lithium metal battery according to claim 1, wherein the positive electrode comprises a positive electrode material selected from the group consisting of lithium nickel-manganese-cobalt oxide, lithium nickel-manganese oxide, lithium nickel-cobalt-aluminum oxide, lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt iron phosphate, lithium sulfide, sulfur, and aluminum.

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