Separator for rechargeable battery and rechargeable battery comprising the same

Abstract

This disclosure relates to a separator for a rechargeable battery and a rechargeable battery including the separator. The separator for the rechargeable battery includes a porous substrate and a coating formed on at least one surface of the porous substrate. The coating includes a core-shell adhesive having a core and a shell surrounding the core, and the shell has adhesive functional groups located at its ends and has structural units containing alkylene glycol groups and cyano groups.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2025-0017138, filed on February 11, 2025, Korean Patent Application No. 10-2025-0017139, filed on February 11, 2025, and Korean Patent Application No. 10-2025-0017144, filed on February 11, 2025, with the entire disclosure of each of the above applications incorporated herein by reference. Technical Field

[0002] This disclosure relates to a separator for a rechargeable battery and a rechargeable battery including the separator. Background Technology

[0003] With the increasing prevalence of battery-powered electronic devices (such as mobile phones, laptops, and electric vehicles), the demand for rechargeable batteries with high energy density and high capacity is growing. Therefore, improving the performance of rechargeable lithium batteries can be advantageous.

[0004] A rechargeable lithium battery includes a positive electrode and a negative electrode containing active materials capable of inserting and deintercalating lithium ions, and generates electrical energy through oxidation and reduction reactions when lithium ions are inserted into the positive electrode and deintercalated from the negative electrode, and when lithium ions are inserted into the negative electrode and deintercalated from the positive electrode.

[0005] The diaphragm includes a porous substrate and a coating formed on at least one surface of the porous substrate. The coating may include an adhesive, thereby increasing adhesion to both the positive and negative electrodes. Among such adhesives, organic adhesives (e.g., polyvinylidene fluoride (PVDF) adhesives) have desired or improved wet adhesion to the positive electrode, but their adhesion to the negative electrode may be relatively low compared to their wet adhesion to the positive electrode.

[0006] Therefore, high wet adhesion to each of the positive and negative electrodes can be advantageous. However, when the content of the adhesive binder is increased to increase the wet adhesion to each of the positive and negative electrodes, the membrane resistance may increase, and the permeability may increase. Summary of the Invention

[0007] This disclosure relates to a separator for rechargeable batteries with low resistance.

[0008] This disclosure also relates to a separator for a rechargeable battery that has high wet adhesion to each of the positive and negative electrodes.

[0009] This disclosure also relates to a separator for a rechargeable battery, the separator comprising a binder capable of increasing the dissociation of lithium ions and forming ion transport channels.

[0010] This disclosure also relates to a separator for a rechargeable battery in which the adhesion between a porous substrate, a heat-resistant layer and an adhesive layer is increased.

[0011] This disclosure also relates to a separator for rechargeable batteries with a low thermal shrinkage rate.

[0012] This disclosure also relates to a rechargeable battery including the separator for the rechargeable battery.

[0013] According to one aspect of this disclosure, a separator for a rechargeable battery includes a porous substrate and a coating formed on at least one surface of the porous substrate, wherein the coating includes a core-shell adhesive having a core and a shell surrounding the core, the shell having adhesive functional groups at its ends and having structural units containing alkylene glycol groups and cyano groups.

[0014] According to another aspect of this disclosure, a separator for a lithium rechargeable battery includes a porous substrate and a coating formed on at least one surface of the porous substrate, wherein the coating includes a mixture of a core-shell binder and a linear binder, and the core-shell binder and the linear binder have the same terminal functional groups.

[0015] According to another aspect of this disclosure, a separator for a lithium rechargeable battery includes a porous substrate and a coating formed on at least one surface of the porous substrate, wherein the coating includes a mixture of a core-shell binder and a linear binder, and a filler, the core-shell binder having a first adhesive functional group and the linear binder having a second adhesive functional group.

[0016] According to another aspect of this disclosure, a rechargeable battery includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode.

[0017] According to one example embodiment, the separator for a rechargeable battery can have low resistance, can increase the degree of lithium ion dissociation, can form ion transport channels, and can have significantly high wet adhesion to each of the positive and negative electrodes, thereby increasing the battery life at room temperature and high temperature.

[0018] The separator for a rechargeable lithium battery according to an example embodiment exhibits significantly high adhesion to each of the positive and negative electrodes, and high adhesion between the porous substrate, the heat-resistant layer, and the adhesive layer. The separator for a rechargeable lithium battery according to an example embodiment can have low resistance, can increase the degree of lithium-ion dissociation, can form ion transport channels, and can increase battery life at both room temperature and high temperature.

[0019] A separator for a rechargeable battery according to an example embodiment can have significantly high wet adhesion to each of the positive and negative electrodes, thereby improving battery safety and lifespan. A separator for a rechargeable battery according to an example embodiment of this disclosure can have a low thermal shrinkage rate to increase the battery's thermal stability and can have improved permeability to reduce membrane resistance. A separator for a rechargeable battery according to an example embodiment can have low membrane resistance, which can increase the degree of lithium-ion dissociation and form ion transport channels, thereby increasing battery life at both room temperature and high temperature. Attached Figure Description

[0020] The above and other objects, features, and advantages of this disclosure will become more apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, in which: Figure 1 and Figure 2 This is a cross-sectional view of a separator for a rechargeable lithium battery according to an example embodiment; Figure 3 and Figure 4 This is a cross-sectional view of a separator for a rechargeable lithium battery according to another example embodiment; Figure 5 This is a cross-sectional view of a separator for a rechargeable lithium battery according to yet another exemplary embodiment; and Figures 6 to 9 This is a schematic diagram illustrating a rechargeable lithium battery according to an example embodiment. Detailed Implementation

[0021] Hereinafter, exemplary embodiments of the present disclosure are described in detail. However, these exemplary embodiments are provided as examples, and the present disclosure is not limited thereto, and is limited only by the scope of the appended claims.

[0022] Unless otherwise stated herein, when a component such as a layer, film, region, plate, etc., is described as being “on” another component, it includes not only the case where the component is “directly on” the other component, but also the case where there is another component between them.

[0023] Unless otherwise stated in this specification, anything indicated in the singular may also include the plural. Furthermore, unless otherwise stated, “A or B” may mean “including A, including B, or including both A and B”.

[0024] As used herein, the term "combination of them" may refer to mixtures, laminates, complexes, copolymers, alloys, blends, and reaction products of the components.

[0025] Here, the term "particle size D50" refers to the average particle size, which represents the diameter of particles that constitute 50% of the cumulative volume in the particle size distribution. Particle size distribution can be measured using methods known to those skilled in the art. For example, particle size distribution can be measured using a particle size analyzer, transmission electron microscopy, or scanning electron microscopy. In another method, the D50 value can be obtained by measuring the particle size using a dynamic light scattering measuring device, performing data analysis to calculate the number of particles for each particle size range, and then calculating the particle size from that. Alternatively, D50 can be measured using laser diffraction. For example, when measured by laser diffraction, after dispersing the particles to be measured in a dispersion medium, the particles can be introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasound at approximately 28 kHz at an output of 60 W, and the D50 based on 50% of the particle size distribution in the measuring device can be calculated.

[0026] In this specification, "(meth)acrylic acid" means acrylic acid and / or methacrylic acid.

[0027] Unless otherwise defined herein, “substitution” means that hydrogen in a compound is substituted by a substituent, which is such as or includes C1 to C30 alkyl, C2 to C30 alkenyl, C2 to C30 alkynyl, C6 to C30 aryl, C7 to C30 alkylaryl, C1 to C30 alkoxy, C1 to C30 heteroalkyl, C3 to C30 heteroalkylaryl, C3 to C30 cycloalkyl, C3 to C15 cycloalkenyl, C6 to C30 cycloalkynyl, C2 to C30 heterocycloalkyl, halogen (F, Cl, Br or I), hydroxyl (-OH), nitro (-NO2), cyano (-CN), amino (-NRR') (wherein R and R' are each independently hydrogen or C1 to C6 alkyl), sulfobetaine (-RR'N) + (CH2) n SO3 - n is a natural number in the range of 1 to 10 (where R and R' are each independently a C1 to C20 alkyl group), carboxybenzene group (-RR'N) + (CH2) n COO -The following groups are used: n is a natural number in the range of 1 to 10 (where R and R' are each independently C1 to C20 alkyl groups), azide (-N3), amidine (-C(=NH)NH2), hydrazine (-NHNH2), hydrazone (=N(NH2)), carbamoyl (-C(=O)NH2), thiol (-SH), acyl (-C(=O)R, where R is hydrogen, C1 to C6 alkyl, C1 to C6 alkoxy or C6 to C12 aryl), carboxyl (-COOH) or a salt thereof (-C(=O)OM, where M is an organic or inorganic cation), sulfonic acid (-SO3H) or a salt thereof (-SO3M, where M is an organic or inorganic cation), phosphate (-PO3H2) or a salt thereof (-PO3MH or -PO3M2, where M is an organic or inorganic cation), and at least one combination thereof.

[0028] In the following text, C1 to C3 alkyl means methyl, ethyl, or propyl. C1 to C10 alkylene can be or include, for example, C1 to C6 alkylene, C1 to C5 alkylene, or C1 to C3 alkylene, such as methylene, ethylene, or propylene. C3 to C20 cycloalkylene can be or include, for example, C3 to C10 cycloalkylene or C5 to C10 cycloalkylene, such as cyclohexylene. C6 to C20 arylene can be or include, for example, C6 to C10 arylene, such as phenylene. C3 to C20 heterocyclic can be or include, for example, C3 to C10 heterocyclic, such as pyridyl.

[0029] In the following text, “heterogeneous” means including one or more heteroatoms, such as or including at least one of N, O, S, Si and P.

[0030] In chemical formulas, Symbols represent parts that are connected to the same or different atoms, groups, or structural units.

[0031] Unless otherwise specified in the chemical formulas described herein, it can be assumed that hydrogen bonds are present in the structure of the chemical formulas.

[0032] In the following text, "alkali metals" refers to elements belonging to Group 1 of the periodic table, such as lithium, sodium, potassium, rubidium, cesium, or francium, which can exist in either a cation or a neutral state.

[0033] When describing numerical ranges in this specification, “X to Y” means “X or greater and Y or less (greater than or equal to X and less than or equal to Y)”.

[0034] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it means that the relevant numerical value includes a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range, such as increments of 0.1%.

[0035] This disclosure will be described in detail. Hereinafter, only rechargeable lithium-ion batteries will be described. However, this disclosure can also be applied to rechargeable batteries using different metal ions besides rechargeable lithium-ion batteries.

[0036] Separator for the first rechargeable lithium battery The separator for a rechargeable lithium battery includes a porous substrate and a coating formed on at least one surface of the porous substrate. The coating includes a core-shell binder having a core and a shell surrounding the core, the shell having adhesive functional groups at its ends, and having structural units containing alkylene glycol groups and cyano groups.

[0037] The separator comprises a coating containing a core-shell binder. The separator exhibits low resistance, increases lithium-ion dissociation, forms ion transport channels, and has high wet adhesion to each of the positive and negative electrodes. Therefore, the separator can increase battery life at both room temperature and high temperatures.

[0038] The wet adhesion force of the diaphragm to the positive electrode can be approximately 0.85 gf / mm or greater.

[0039] The wet adhesion of the diaphragm to the negative electrode can be approximately 0.79 gf / mm or greater.

[0040] The diaphragm can have a membrane resistance of about 0.65Ω or less.

[0041] Core-shell binders can provide low resistance, high lithium-ion dissociation, ion transport channels, and high wet adhesion to each of the positive and negative electrodes.

[0042] The core-shell binder can be or includes an aqueous adhesive. Therefore, the core-shell binder can be included in an aqueous solvent (e.g., water) to provide an aqueous coating, thereby allowing the manufacture of environmentally friendly membranes.

[0043] The core-shell binder can be or includes particulate binders. For example, the average particle size D50 of the particulate core-shell binder can be about 700 nm or less, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, etc. The core-shell binder can be included in the coating and provides adhesion within the above-mentioned ranges: 0nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm, 700nm, and in the ranges from about 200nm to about 700nm, 300nm to 700nm, or 300nm to 600nm.

[0044] The average particle size D50 can be adjusted by controlling the reaction temperature and stirring speed during the preparation of the core-shell binder.

[0045] In the core-shell binder, the amount of core can range from about 40 wt% to about 90 wt%, for example, 50 wt% to 70 wt%, and the amount of shell can range from about 10 wt% to about 60 wt%, for example, 30 wt% to 50 wt%. Within the above ranges, the mechanical strength of the core-shell binder can be high, thereby increasing the strength of the diaphragm and providing the aforementioned effects of the diaphragm.

[0046] nuclear The core may be or include an organic core and may include a first copolymer.

[0047] The first copolymer may be a copolymer of at least one or a combination thereof of aromatic vinyl monomers, diene monomers, (meth)acrylate monomers, ester monomers, olefin monomers and urethane monomers.

[0048] According to one example embodiment, the first copolymer may be or include a copolymer of at least one or a combination thereof of aromatic vinyl monomers and (meth)acrylate monomers.

[0049] Aromatic vinyl monomers may be or include styrene, C1-C 10 At least one of alkyl-substituted styrene, halogen-substituted styrene, or combinations thereof. C1-C 10 Alkyl-substituted styrene may include at least one of ethylstyrene, methylstyrene, etc.

[0050] (Meth)acrylate monomers may be or include substituted or unsubstituted C1-C atoms in the ester moiety. 10 Alkyl (meth)acrylates.

[0051] The first copolymer may be or include copolymers of diene monomers and aromatic vinyl monomers. The diene monomers may be or include conjugated diene monomers (such as 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 1,3-pentadiene, or chloroprene) or non-conjugated diene monomers (such as vinylnorbornene, dicyclopentadiene, or 1,4-hexadiene). Aromatic vinyl monomers are as described above.

[0052] The first copolymer may be or include a rubber polymer. For example, the rubber polymer may be or include at least one of butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylic rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, isoprene rubber, isobutylene-isoprene rubber, ethylene-propylene rubber, ethylene-propylene-diene rubber, polyorganosiloxane-poly(meth)acrylate rubber, fluororubber, or combinations thereof.

[0053] The core may include either a cross-linked form of the first copolymer or a non-cross-linked form of the first copolymer.

[0054] shell The shell surrounds the surface of the core and includes a second copolymer attached to the surface of the core.

[0055] The second copolymer has alkylene glycol-containing structural units and cyano-containing structural units, and has an adhesive functional group at one end. The other end of the second copolymer can be bonded to the surface of the core. The alkylene glycol-containing structural units and the cyano-containing structural units can exist between the surface of the core and the adhesive functional group. Both the alkylene glycol-containing structural units and the cyano-containing structural units can be repeating units in the second copolymer.

[0056] Alkyl glycol-containing structural units, serving as lithium-ion conduction units, can form lithium-ion transport channels and reduce the resistance of the separator, thereby improving battery life at room temperature and high temperature.

[0057] The cyano-containing structural units, which serve as lithium-ion conduction units, can form lithium-ion transport channels and reduce the resistance of the separator, thereby improving battery life at room temperature and high temperature.

[0058] According to one example embodiment, the second copolymer may have alkylene glycol-containing structural units and cyano-containing structural units in the main chain of the second copolymer.

[0059] The structural unit containing an alkylene glycol group can be represented by the following chemical formula 1, and the second copolymer may include one or more units of the following chemical formula 1: Chemical Formula 1: .

[0060] In the above chemical formula 1, n equals 0 or 1, and R 1 It includes, or may include, substituted or unsubstituted C1-C, whether linear or branched. 10 Alkylene.

[0061] In one example, chemical formula 1 can be a combination of one or more of the following chemical formulas: chemical formula 1-1, chemical formula 1-2, and chemical formula 1-3: Chemical formula 1-1: .

[0062] Chemical formulas 1-2: .

[0063] Chemical formulas 1-3: .

[0064] The structural unit containing an alkylene glycol group can be derived from at least one of ethylene glycol, n-propylene glycol, and propylene glycol carbonate. That is, the second copolymer can include units derived from at least one of polyethylene glycol (PEG), polypropylene glycol, and polypropylene glycol carbonate.

[0065] The content of alkylene glycol-containing structural units relative to the 100 mol% repeating units of the second copolymer can range from about 15 mol% to about 85 mol%, 15 mol% to 75 mol%, 25 mol% to 85 mol%, 25 mol% to 70 mol%, 30 mol% to 75 mol%, or 30 mol% to 70 mol%. When the content of alkylene glycol-containing structural units is within the above range, the membrane can ensure desired or improved antioxidant properties and exhibit adhesion, heat resistance, and breathability.

[0066] The cyano-containing structural unit can be represented by the following chemical formula 2, and the second copolymer may include one or more units of the following chemical formula 2: Chemical formula 2: .

[0067] In chemical formula 2 above, R 3 and R 4 Each is independently hydrogen or C1-C3 alkyl, L 1 It is or includes -C(=O)-, -C(=O)O-, -OC(=O)-, -O-, or -C(=O)NH-, where x is an integer in the range of 0 to 2, and L 2 It includes, or includes, substituted or unsubstituted C1-C 10 Alkylene, substituted or unsubstituted C3-C 20 Cycloalkylene, substituted or unsubstituted C6-C 20 aryl or substituted or unsubstituted C3-C 20 A subheterocyclic base, where y is an integer in the range of 0 to 2.

[0068] The cyano-containing structural unit may be or includes structural units derived from, for example, (meth)acrylonitrile, olefin nitrile, (meth)acrylic cyanoalkyl ester, or 2-(ethoxy)alkane nitrile. Here, the olefin may be or includes C2-C 20 Olefins, C2-C 10 An olefin or a C2-C6 olefin, and the alkyl group may be or include C1-C6. 20 Alkyl, C1-C 10 Alkyl or C1-C6 alkyl. Furthermore, alkanes can be or include C1-C6 alkyl groups. 20 Alkanes, C1-C 10 Alkanes or C1-C6 alkanes.

[0069] Olefin nitrile can be or includes, for example, allyl cyanide, 4-pentenonitrile, 3-pentenonitrile, 2-pentenonitrile, or 5-hexenonitrile. (Meth)acrylate cyanoalkyl ester can be or includes, for example, (meth)acrylate methyl cyanoacrylate, (meth)acrylate ethyl cyanoacrylate, (meth)acrylate propyl cyanoacrylate, or (meth)acrylate octyl cyanoacrylate. 2-(ethoxy)alkane nitrile can be or includes, for example, 2-(ethoxy)acetonitrile or 2-(ethoxy)propionitrile.

[0070] The content of cyano-containing structural units relative to the 100 mol% repeating units of the second copolymer can be in the range of about 15 mol% to 80 mol%, for example, 15 mol% to 70 mol%, 25 mol% to 80 mol%, 25 mol% to 65 mol%, 30 mol% to 70 mol%, or 30 mol% to 65 mol%. When the content of cyano-containing structural units is within the above range, the membrane can ensure the desired or improved antioxidant properties and can exhibit adhesion, heat resistance, and air permeability.

[0071] The total content of alkylene glycol-containing structural units and cyano-containing structural units, relative to the 100 mol% repeating units of the second copolymer, can be about 95 mol% or more, for example, in the range of about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-mentioned membrane effect can be easily achieved.

[0072] The second copolymer may also include structural units derived from (meth)acrylic acid or (meth)acrylate.

[0073] The second copolymer may include structural units derived from (meth)acrylic acid or (meth)acrylate in the main chain of the second copolymer.

[0074] For example, the second copolymer may include structural units derived from (meth)acrylic acid.

[0075] Structural units derived from (meth)acrylic acid or (meth)acrylates can include lithium cations in the unit structure, thus providing lithium cations through a dissociation process. Therefore, the membrane can provide the effect of increasing lithium cation concentration and reducing resistance. Furthermore, the membrane can have carboxyl functional groups to further increase adhesion. In addition, the membrane can further increase adhesion to ensure high adhesion to the electrode and can provide desired or improved heat resistance, permeability, and oxidation resistance. Furthermore, dispersibility in compositions for coatings, including core-shell binders, can be improved.

[0076] In structural units derived from (meth)acrylates or (meth)acrylic acid, the (meth)acrylate can be or include a conjugate base of (meth)acrylic acid, a (meth)acrylate salt, or a derivative thereof. Structural units derived from (meth)acrylates or (meth)acrylic acid can be represented by, for example, the following chemical formulas 3, 4, or 5, or combinations thereof: Chemical formula 3: .

[0077] Chemical formula 4: .

[0078] Chemical formula 5: .

[0079] In chemical formulas 3 to 5 above, R 5 R 6 R 7 R 8 R 9 and R 10 Each is independently hydrogen or methyl, and in the above chemical formula 4, M is or includes an alkali metal.

[0080] Alkali metals can be or include at least one of, for example, lithium, sodium, potassium, rubidium, or cesium. For example, an alkali metal can be lithium.

[0081] The content of structural units derived from (meth)acrylate or (meth)acrylic acid in the repeating units of the second copolymer can be in the range of about 0 mol% to about 70 mol%, for example, 0.1 mol% to 30 mol%, 0.1 mol% to 25 mol%, 1 mol% to 25 mol%, 1 mol% to 20 mol%, or 5 mol% to 20 mol%. When the content of structural units derived from (meth)acrylate or (meth)acrylic acid is within the above range, the membrane can exhibit desired or improved adhesion, heat resistance, air permeability, and oxidation resistance.

[0082] The structural units derived from (meth)acrylate or (meth)acrylic acid may include structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above, in which case the structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above may be included in a molar ratio in the range of about 10:1 to about 1:2 or 10:1 to 1:1 or 5:1 to 1:1.

[0083] The total content of the alkylene glycol-containing structural units, the cyano-containing structural units, and the structural units derived from (meth)acrylate or (meth)acrylic acid, relative to the 100 mol% repeating units of the second copolymer, can be about 95 mol% or more, for example, in the range of about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-mentioned membrane effect can be easily achieved.

[0084] The second copolymer can be provided in various forms, such as alternating polymers with alternating structural units, random polymers with randomly distributed structural units, or grafted polymers in which some structural units are grafted.

[0085] The shell has an adhesive functional group at one end.

[0086] The shell may include a second copolymer having the same adhesive functional group at one end, or may include a second copolymer having a different type of adhesive functional group at one end.

[0087] The second copolymer may have one type of adhesive functional group at one end, or it may have two or more different types of adhesive functional groups at one end.

[0088] The adhesive functional group can bond to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid.

[0089] In one example, the adhesive functional group can be bonded to a structural unit containing an alkylene glycol group.

[0090] Cohesive functional groups can be or include functional groups capable of forming chemical or physical bonds. For example, cohesive functional groups can undergo hydrogen bonding or covalent bond rearrangement (or reconstruction).

[0091] The adhesive functional group may include oxygen, nitrogen or sulfur with high electronegativity, and may be or include one or more of the following groups: -COOH group, -OH group, -NH2 group, -C(=O)H group, -C(=O)NH2 group and -SS- group.

[0092] The adhesive functional group can undergo metathesis and can be or include functional groups having, for example, a -SS- group. For example, a functional group having a -SS- group can be represented by the following chemical formula 6: Chemical Formula 6: .

[0093] In chemical formula 6 above, R 11 It includes, or includes, substituted or unsubstituted C1-C 10Alkyl or substituted or unsubstituted C6-C 10 Aryl.

[0094] R 11 It may be or include C1-C5 alkyl groups substituted with amino groups or C6-C groups substituted with amino groups. 10 Aryl.

[0095] Functional groups having the -SS- group can be or include -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

[0096] The adhesive functional group can be directly bonded to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid.

[0097] The adhesive functional group can also be bonded to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid through a linker.

[0098] The linker can be or includes a functional group in the main chain having at least one of carbon, oxygen, nitrogen and sulfur.

[0099] The linker can be represented by at least one of the following chemical formulas 7-1 to 7-12: Chemical formula 7-1: .

[0100] Chemical formula 7-2: .

[0101] Chemical formula 7-3: .

[0102] Chemical formula 7-4: .

[0103] Chemical formula 7-5: .

[0104] Chemical formula 7-6: .

[0105] Chemical formula 7-7: .

[0106] Chemical formulas 7-8: .

[0107] Chemical formulas 7-9: .

[0108] Chemical formula 7-10: .

[0109] Chemical formula 7-11: .

[0110] Chemical formula 7-12: .

[0111] In the chemical formulas 7-1 to 7-12 above, n and m are each integers greater than or equal to 0, and R a R b R c R d and R e Each is independently hydrogen or substituted or unsubstituted C1-C 10 alkyl.

[0112] Linking groups can be bonded to structural units containing alkylene glycol groups.

[0113] The linker can be bonded to structural units containing alkylene glycol groups using typical methods known to those skilled in the art. For example, the following scheme can be referenced.

[0114] Reaction scheme 1:

[0115] Reaction scheme 2:

[0116] Reaction scheme 3:

[0117] Reaction scheme 4:

[0118] Reaction scheme 5:

[0119] Reaction scheme 6:

[0120] Reaction scheme 7:

[0121] Reaction scheme 8:

[0122] Reaction scheme 9:

[0123] Reaction scheme 10:

[0124] Reaction scheme 11:

[0125] The second copolymer can be prepared by polymerizing a monomer that provides a cyano-containing structural unit (e.g., a monomer that provides a unit of chemical formula 2 above) and a monomer that provides a alkylene glycol-containing structural unit (e.g., a monomer that provides a unit of chemical formula 1 above), and then introducing an adhesive functional group at its end.

[0126] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of alkylene glycol-containing structural units having adhesive functional groups at their ends and (B) monomers providing cyano-containing structural units. In this case, the mass ratio can be set such that, in a total of 100 parts by mass, the content of (A) is in the range of about 10 parts by mass to about 90 parts by mass, for example, 20 parts by mass to 80 parts by mass or 30 parts by mass to 70 parts by mass (e.g., 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 20 parts by mass, 21 parts by mass, 2...). 2 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight The quantities are approximately 10 parts by weight to approximately 90 parts by weight, for example, 20 parts by weight to 80 parts by weight or 30 parts by weight to 70 parts by weight (e.g., parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, 85 parts by weight, 86 parts by weight, 87 parts by weight, 88 parts by weight, 89 parts by weight, and 90 parts by weight), and the content of (B) is in the range of about 10 parts by weight to about 90 parts by weight, for example, 20 parts by weight to 80 parts by weight or 30 parts by weight to 70 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight (Quantities: 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts).

[0127] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of alkylene glycol-containing structural units having adhesive functional groups at their ends, (B) a monomer providing cyano-containing structural units, and (C) (meth)acrylate or (meth)acrylic acid. In this case, a mass ratio can be set such that, in a total of 100 parts by mass, the content of (A) is in the range of about 10 parts by mass to about 80 parts by mass, for example, 20 parts by mass to 70 parts by mass, 30 parts by mass to 70 parts by mass, or 70 parts by mass to 60 parts by mass (for example, 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 20 parts by mass, 21 parts by mass, 22 parts by mass, 23 parts by mass, 24 parts by mass, 25 parts by mass, 26 parts by mass, 27 parts by mass, 28 parts by mass, 29 parts by mass, 30 parts by mass, 31 parts by mass, 32 parts by mass, 33 parts by mass, 34 parts by mass, 35 parts by mass, 36 parts by mass, 37 parts by mass, 38 parts by mass, 39 parts by mass, 40 parts by mass, 41 parts by mass, 42 parts by mass, 4...). 3 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight; and the content of (B) is in the range of about 10 parts by weight to about 80 parts by weight, for example, 20 parts by weight to 70 parts by weight, 30 parts by weight to 70 parts by weight, or 30 parts by weight to 60 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 3 7 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight The amounts are approximately 1 part by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, and 80 parts by weight, and the content of (C) is in the range of about 1 part by weight to about 30 parts by weight, for example, 5 parts by weight to 30 parts by weight or 5 parts by weight to 20 parts by weight (e.g., 1 part by weight, 2 parts by weight). (3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts).

[0128] The content of the core-shell binder in the coating can be in the range of about 5 wt% to about 30 wt%, for example 8 wt% to 25 wt%, 8 wt% to 20 wt%, or 10 wt% to 20 wt%. Within the above range, the effect of the diaphragm can be easily achieved.

[0129] In addition to the core-shell binder, the coating may also include an adhesive binder. For example, the adhesive binder may include at least one of acrylate compounds or derivatives thereof, diallyl phthalate compounds or derivatives thereof, polyimide compounds or derivatives thereof, or polyurethane compounds or derivatives thereof. For example, the adhesive binder may be cross-linked polymethyl methacrylate.

[0130] In addition to core-shell binders, coatings may also include adhesives.

[0131] The adhesive may be or may include a heat-resistant adhesive (or a heat-resistant bonding adhesive).

[0132] The adhesive may be or include a non-core-shell adhesive but may not include a core-shell adhesive.

[0133] The heat-resistant adhesive may include a (meth)acrylic adhesive, which comprises structural units containing sulfonic acid groups. The (meth)acrylic adhesive may also include at least one of structural units derived from (meth)acrylates or (meth)acrylic acid, structural units containing cyano groups, and structural units derived from (meth)acrylamide.

[0134] The content of the heat-resistant binder in the coating can be in the range of about 1 wt% to about 25 wt%, for example, 1 wt% to 20 wt%, 1 wt% to 15 wt%, or 2 wt% to 15 wt%.

[0135] The coating may also include fillers.

[0136] The average particle size D50 of the filler can be about 0.4 μm or smaller, for example, 0.35 μm or smaller, 0.3 μm or smaller, or in the range of about 0.1 μm to about 0.3 μm. Within the above range, it can have the effect of improving heat resistance properties.

[0137] The surface of the filler may or may not be modified.

[0138] The filler may be or include at least one of, for example, inorganic fillers, organic fillers, organic-inorganic composite fillers, or combinations thereof. Inorganic fillers may include ceramic materials capable of improving heat resistance. Inorganic fillers may include at least one of, for example, metal oxides, quasi-metal oxides, metal fluorides, metal hydroxides, or combinations thereof. Inorganic fillers may include at least one of, for example, Al₂O₃, SiO₂, TiO₂, SnO₂, CeO₂, MgO, NiO, CaO, GaO, ZnO, ZrO₂, Y₂O₃, SrTiO₃, BaTiO₃, Mg(OH)₂, boehmite, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may include at least one of, acrylic compounds, imide compounds, amide compounds, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may have a core-shell structure, but this disclosure is not limited thereto. For example, the filler may include boehmite.

[0139] The packing material can have a spherical shape, a plate shape, a cubic shape, or no fixed shape. For example, the packing material can be cubic in shape, and cubic packing material can help improve air permeability.

[0140] The filler may be included in a suitable or desired amount relative to the heat-resistant binder. According to one example embodiment, the heat-resistant binder and filler may be included in a mass ratio of about 1:10 to about 1:50, for example, 1:20 to 1:30. Within the above range, this can have the effect of improving heat resistance in the electrolyte.

[0141] The filler content in the coating can range from about 50 wt% to about 99 wt%, for example, 70 wt% to 99 wt%, 75 wt% to 99 wt%, 80 wt% to 99 wt%, 85 wt% to 99 wt%, 90 wt% to 99 wt%, or 95 wt% to 99 wt%. When the filler content is within the above range, desired or improved heat resistance, durability, oxidation resistance, and stability can be exhibited.

[0142] The coating may be or include a single layer comprising a core-shell binder, a heat-resistant binder, and a filler. In one example, the coating may be formed by or comprise a composition comprising a core-shell binder, a heat-resistant binder, and a filler.

[0143] The coatings may each have a thickness in the range of about 0.01 μm to about 20 μm, and within the above range, they may have a thickness in the range of about 1 μm to about 10 μm, or 1 μm to 5 μm, or 1 μm to 3 μm.

[0144] The coating may include a heat-resistant layer and an adhesive layer. The heat-resistant layer includes a heat-resistant adhesive and a filler, and the adhesive layer is located on the heat-resistant layer and includes a core-shell adhesive. The heat-resistant layer may be formed of a composition containing a heat-resistant adhesive and a filler but without a core-shell adhesive, or may include a composition containing a heat-resistant adhesive and a filler but without a core-shell adhesive.

[0145] Each heat-resistant layer may have a thickness ranging from about 0.01 μm to about 20 μm, and within the aforementioned range, may have a thickness ranging from about 1 μm to about 10 μm, from 1 μm to 5 μm, or from 1 μm to 3 μm.

[0146] Each adhesive layer may have a thickness in the range of about 0.01 μm to about 20 μm, and within the range therema, it may have a thickness in the range of about 0.1 μm to about 10 μm, 0.1 μm to 5 μm or 0.1 μm to 1 μm.

[0147] The coating is located on at least one surface of the porous substrate.

[0148] The ratio of coating thickness to porous substrate thickness can be in the range of about 0.05 to about 0.5, for example, 0.05 to 0.4, 0.05 to 0.3, or 0.1 to 0.2. Within the above range, the diaphragm can exhibit desired or improved permeability, heat resistance, and adhesion. Here, when the coating is formed on only one surface of the porous substrate, "coating thickness" is the thickness of one coating layer, and when the coating is formed on both surfaces of the porous substrate, "coating thickness" is the total thickness of the two coating layers.

[0149] porous substrate Porous substrates can be or include substrates having multiple pores and are typically used in electrochemical devices. Not limited thereto, porous substrates can be or include polymer membranes formed of or comprising any polymer such as or comprising at least one of the following, or formed of or comprising copolymers or mixtures of two or more of them: polyolefins (such as polyethylene or polypropylene), polyesters (such as polyethylene terephthalate or polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, and polytetrafluoroethylene (e.g., Teflon).

[0150] The porous substrate can be or includes, for example, a polyolefin substrate comprising polyolefins, and the polyolefin substrate can have desired or improved shut-off functionality, thus contributing to improved battery safety. The polyolefin substrate can be or includes at least one of, for example, polyethylene monolayer film, polypropylene monolayer film, polyethylene / polypropylene bilayer film, polypropylene / polyethylene / polypropylene trilayer film, and polyethylene / polypropylene / polyethylene trilayer film. Furthermore, the porous substrate may include non-olefin resins in addition to olefin resins, or may include copolymers of olefin and non-olefin monomers.

[0151] The thickness of the porous substrate can be in the range of about 1 μm to about 40 μm, for example, 1 μm to 30 μm, 1 μm to 20 μm or 5 μm to 15 μm.

[0152] Separators for rechargeable lithium-ion batteries can exhibit desired or improved permeability and can have permeability values, for example, less than about 200 seconds / 100cc, or for example, 190 seconds / 100cc or less, or 180 seconds / 100cc or less. That is, the permeability value of the separator can be less than about 40 seconds / 100cc per μm of thickness, for example, 30 seconds / 100cc or less per μm of thickness, or 25 seconds / 100cc or less per μm of thickness. Here, permeability represents the time (in seconds) it takes for 100cc of air to pass through a unit thickness of separator. Permeability per unit thickness can be obtained by measuring the permeability over the entire thickness of the separator and dividing the measured permeability by the thickness. Permeability can be measured by measuring the time (in seconds) it takes for 100cc of air to pass through the separator using a measuring device (EG01-55-1MR manufactured by Asahi Seiko).

[0153] A separator for a rechargeable battery can be formed by coating one or both surfaces of a porous substrate with a composition for forming a coating, followed by drying the composition. Drying can be performed using typical methods known to those skilled in the art.

[0154] Figure 1 This is a cross-sectional view showing a separator for a rechargeable lithium battery according to an example embodiment.

[0155] Reference Figure 1 The separator for a rechargeable lithium battery includes a porous substrate 1 and a coating 2 on each of two opposing surfaces of the porous substrate 1. The coating 2 is a laminate of a heat-resistant layer 5 and an adhesive layer 7. The heat-resistant layer 5 may include a filler 3 and a heat-resistant adhesive 4. The adhesive layer 7 may be located on the heat-resistant layer 5 and may include a core-shell adhesive 6.

[0156] Figure 2 This is a cross-sectional view showing a separator for a rechargeable lithium battery according to another example embodiment.

[0157] Reference Figure 2 The separator for a rechargeable lithium battery includes a porous substrate 1 and coatings 2 on two surfaces of the porous substrate 1. The coatings 2 may include fillers 3, heat-resistant binders 4, and core-shell binders 6.

[0158] The coating may also include a linear binder. In this regard, the separator for a second rechargeable lithium battery and the separator for a third rechargeable lithium battery are described in detail below.

[0159] Separator for a second rechargeable lithium battery A separator for a rechargeable lithium battery includes a porous substrate and a coating formed on at least one surface of the porous substrate, wherein the coating may include a mixture of a core-shell binder and a linear binder, and the core-shell binder and the linear binder may have the same terminal functional groups.

[0160] Core-shell binders and linear binders can have the same terminal functional groups. These same terminal functional groups can interact with each other to increase the bonding between the core-shell binder and the linear binder, thereby increasing the adhesion of the coating to each of the positive and negative electrodes.

[0161] Compared to core-shell binders, linear binders can relatively easily fill empty spaces in the coating. For example, when the coating includes fillers as described below, linear binders can easily fill the empty spaces between the fillers. Therefore, the diaphragm can have high adhesion between the coating and the porous substrate. Furthermore, when the coating includes a heat-resistant layer containing fillers as described below and an adhesive layer located on the heat-resistant layer, the diaphragm can provide high adhesion between the heat-resistant layer and the adhesive layer.

[0162] The terminal functional groups are described in more detail below.

[0163] Core-shell binder The coating includes a core-shell binder. The separator has low resistance, which increases the dissociation of lithium ions and forms ion transport channels, and it exhibits high wet adhesion to each of the positive and negative electrodes. The separator can increase battery life at both room temperature and high temperature.

[0164] The wet adhesion of the diaphragm to the positive electrode can be approximately 1.1 gf / mm or greater.

[0165] The wet adhesion of the diaphragm to the negative electrode can be approximately 0.84 gf / mm or greater.

[0166] Core-shell binders can provide low resistance, high lithium-ion dissociation, ion transport channels, and high adhesion to each of the positive and negative electrodes.

[0167] The core-shell binder can be or includes an aqueous adhesive. Therefore, the core-shell binder can be used in an aqueous solvent (e.g., water) to provide an aqueous coating, thereby allowing the manufacture of environmentally friendly membranes.

[0168] The core-shell binder can be or includes particulate binders. For example, the average particle size D50 of the particulate core-shell binder can be about 700 nm or less, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, etc. 0nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm, 700nm, in the range of approximately 200nm to approximately 700nm, 300nm to 700nm, or 300nm to 600nm.

[0169] The average particle size D50 can be adjusted by controlling the reaction temperature and stirring speed during the preparation of the core-shell binder.

[0170] In the core-shell binder, the amount of core can range from about 40 wt% to about 90 wt%, for example, 50 wt% to 70 wt%, and the amount of shell can range from about 10 wt% to about 60 wt%, for example, 30 wt% to 50 wt%. Within the above ranges, the mechanical strength of the core-shell binder can be high, thereby increasing the strength of the diaphragm and providing the aforementioned effects of the diaphragm.

[0171] nuclear The core may be or include an organic core, and may include a first copolymer.

[0172] The details of the core are substantially the same as those described in the core-shell adhesive for the separator used in the first rechargeable lithium battery. Therefore, a detailed description of the core is omitted.

[0173] shell The shell surrounds the surface of the core and includes a second copolymer attached to the surface of the core.

[0174] The second copolymer has alkylene glycol-containing structural units and cyano-containing structural units, and has an adhesive functional group at one end. The other end of the second copolymer can be bonded to the surface of the core. The alkylene glycol-containing structural units and the cyano-containing structural units can exist between the surface of the core and the adhesive functional group.

[0175] The structural unit containing alkylene glycol groups can be or includes lithium-ion conducting units, and can form lithium-ion transport channels and reduce the resistance of the separator, thereby improving the battery life at room temperature and high temperature.

[0176] The cyano-containing structural unit can be or includes a lithium-ion conducting unit, and can form a lithium-ion transport channel and reduce the resistance of the separator, thereby improving the battery life at room temperature and high temperature.

[0177] The second copolymer may have structural units containing alkylene glycol groups and structural units containing cyano groups in the main chain of the second copolymer.

[0178] The structural unit containing an alkylene glycol group can be represented by the above chemical formula 1, and the second copolymer can include one or more units of the above chemical formula 1.

[0179] The above chemical formula 1 can be a combination of one or more of the above chemical formulas 1-1, 1-2 and 1-3.

[0180] The structural unit containing an alkylene glycol group can be derived from at least one of ethylene glycol, n-propylene glycol, and propylene glycol carbonate. That is, the second copolymer can include units derived from at least one of PEG, polypropylene glycol, and polypropylene glycol carbonate.

[0181] The content of alkylene glycol-containing structural units relative to the 100 mol% repeating units of the second copolymer can range from about 15 mol% to about 85 mol%, 15 mol% to 75 mol%, 25 mol% to 85 mol%, 25 mol% to 70 mol%, 30 mol% to 75 mol%, or 30 mol% to 70 mol%. When the content of alkylene glycol-containing structural units is within the above range, the membrane can ensure desired or improved antioxidant properties and can exhibit adhesion, heat resistance, and breathability.

[0182] The cyano-containing structural unit can be represented by the above chemical formula 2, and the second copolymer can include one or more units of the above chemical formula 2.

[0183] The cyano-containing structural unit may be or includes structural units derived from, for example, (meth)acrylonitrile, olefin nitrile, (meth)acrylic cyanoalkyl ester, or 2-(ethoxy)alkane nitrile. Here, the olefin may be or includes C2-C20 Olefins, C2-C 10 An olefin or a C2-C6 olefin, and the alkyl group may be or include C1-C6. 20 Alkyl, C1-C 10 Alkyl or C1-C6 alkyl. Furthermore, alkanes can be or include C1-C6 alkyl groups. 20 Alkanes, C1-C 10 Alkanes or C1-C6 alkanes.

[0184] Olefin nitrile may be or include at least one of, for example, allyl cyanide, 4-pentenonitrile, 3-pentenonitrile, 2-pentenonitrile, or 5-hexenonitrile. (Meth)acrylate cyanoalkyl ester may be or include at least one of, for example, cyanomethyl (meth)acrylate, cyanoethyl (meth)acrylate, cyanopropyl (meth)acrylate, or cyanooctyl (meth)acrylate. 2-(ethoxy)alkane nitrile may be or include, for example, 2-(ethoxy)acetonitrile or 2-(ethoxy)propionitrile.

[0185] The content of cyano-containing structural units relative to the 100 mol% repeating units of the second copolymer can range from about 15 mol% to about 80 mol%, for example, 15 mol% to 70 mol%, 25 mol% to 80 mol%, 25 mol% to 65 mol%, 30 mol% to 70 mol%, or 30 mol% to 65 mol%. When the content of cyano-containing structural units is within the above range, the membrane can ensure the desired or improved antioxidant properties and can exhibit adhesion, heat resistance, and air permeability.

[0186] According to an example embodiment, the total content of alkylene glycol-containing structural units and cyano-containing structural units relative to 100 mol% of repeating units in the second copolymer can be in the range of about 95 mol% or more, for example, from about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-described effect of the diaphragm can be easily achieved.

[0187] The second copolymer may also include structural units derived from (meth)acrylic acid or (meth)acrylate. The second copolymer may include structural units derived from (meth)acrylic acid or (meth)acrylate in its main chain. For example, the second copolymer may include structural units derived from (meth)acrylic acid.

[0188] Structural units derived from (meth)acrylic acid or (meth)acrylates can include lithium cations in the unit structure, thus providing lithium cations through a dissociation process. Therefore, the membrane can provide the effect of increasing lithium cation concentration and reducing resistance. Furthermore, the membrane can have carboxyl functional groups to further increase adhesion. In addition, the membrane can further increase adhesion to ensure high adhesion to the electrode and can provide desired or improved heat resistance, permeability, and oxidation resistance. Furthermore, dispersibility in compositions for coatings, including core-shell binders, can be improved.

[0189] In structural units derived from (meth)acrylates or (meth)acrylic acid, the (meth)acrylate can be or include a conjugate base of (meth)acrylic acid, a (meth)acrylate salt, or a derivative thereof. Structural units derived from (meth)acrylates or (meth)acrylic acid can be represented, for example, by chemical formulas 3, 4, or 5 above, or combinations thereof.

[0190] The content of structural units derived from (meth)acrylate or (meth)acrylic acid in the repeating units of the second copolymer can be in the range of about 0.1 mol% to about 30 mol%, 0.1 mol% to 25 mol%, 1 mol% to 25 mol%, 1 mol% to 20 mol%, or 5 mol% to 20 mol%. When the content of structural units derived from (meth)acrylate or (meth)acrylic acid is within the above range, the membrane can exhibit desired or improved adhesion, heat resistance, air permeability, and oxidation resistance.

[0191] As an example, structural units derived from (meth)acrylates or (meth)acrylic acid may include structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above, in which case the structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above may be included in a molar ratio ranging from about 10:1 to about 1:2 or from 10:1 to 1:1 or from 5:1 to 1:1.

[0192] The total content of the alkylene glycol-containing structural units, the cyano-containing structural units, and the structural units derived from (meth)acrylate or (meth)acrylic acid, relative to the 100 mol% repeating units of the second copolymer, can be about 95 mol% or more, for example, in the range of about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-mentioned membrane effect can be easily achieved.

[0193] The second copolymer can be provided in various forms, such as alternating polymers with alternating structural units, random polymers with randomly distributed structural units, or grafted polymers in which some structural units are grafted.

[0194] The shell has a functional group at one end. This functional group may be or may include adhesive functional groups.

[0195] The shell may include a second copolymer having the same adhesive functional group at one end, or may include a second copolymer having a different type of adhesive functional group at one end.

[0196] The second copolymer may have one type of adhesive functional group at one end, or it may have two or more different types of adhesive functional groups at one end.

[0197] The adhesive functional group can bond to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid.

[0198] Adhesive functional groups can bond to structural units containing alkylene glycol groups.

[0199] Cohesive functional groups can be or include functional groups capable of forming chemical or physical bonds. For example, cohesive functional groups can undergo hydrogen bonding or covalent rearrangement.

[0200] The adhesive functional group may include oxygen, nitrogen or sulfur with high electronegativity, and may be or include one or more of the functional groups having, for example, -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2 and -SS- groups.

[0201] The adhesive functional group can undergo metathesis and can be or include functional groups having, for example, a -SS- group. For example, a functional group having a -SS- group can be represented by the above chemical formula 6.

[0202] In chemical formula 6 above, R 11 It may be or include C1-C5 alkyl groups substituted with amino groups or C6-C groups substituted with amino groups. 10 Aryl.

[0203] Functional groups with the -SS- group can be -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

[0204] The adhesive functional group can be directly bonded to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid.

[0205] The adhesive functional group can be bonded to structural units containing alkylene glycol groups, cyano groups, or derived from (meth)acrylates or (meth)acrylic acid through a linker.

[0206] The linker can be or includes a functional group in the main chain having at least one of carbon, oxygen, nitrogen and sulfur.

[0207] The linker can be represented by at least one of the above chemical formulas 7-1 to 7-12.

[0208] Linking groups can be bonded to structural units containing alkylene glycol groups.

[0209] In this respect, the linker can be bonded to structural units containing alkylene glycol groups using typical methods known to those skilled in the art. For example, the reaction schemes 1 to 11 above can be referred to.

[0210] The second copolymer can be prepared by polymerizing a monomer that provides a cyano-containing structural unit (e.g., a monomer that provides a unit of chemical formula 2 above) and a monomer that provides a alkylene glycol-containing structural unit (e.g., a monomer that provides a unit of chemical formula 1 above), and then introducing an adhesive functional group at its end.

[0211] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of alkylene glycol-containing structural units having adhesive functional groups at their ends and (B) monomers providing cyano-containing structural units. In this case, the mass ratio can be set such that, in a total of 100 parts by mass, the content of (A) is in the range of about 10 parts by mass to about 90 parts by mass, for example, 20 parts by mass to 80 parts by mass, 30 parts by mass to 70 parts by mass, or 30 parts by mass to 50 parts by mass (e.g., 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 20 parts by mass, 2...). 1 part by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight The quantities are approximately 10 parts by weight to approximately 90 parts by weight, for example, 20 parts by weight to 80 parts by weight, or 30 parts by weight to 70 parts by weight, or 50 parts by weight to 70 parts by weight (e.g., parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, 85 parts by weight, 86 parts by weight, 87 parts by weight, 88 parts by weight, 89 parts by weight, and 90 parts by weight), and the content of (B) is in the range of about 10 parts by weight to about 90 parts by weight, for example, 20 parts by weight to 80 parts by weight, or 30 parts by weight to 70 parts by weight, or 50 parts by weight to 70 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight (Quantities: 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts).

[0212] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of alkylene glycol-containing structural units having adhesive functional groups at their ends, (B) a monomer providing cyano-containing structural units, and (C) (meth)acrylate or (meth)acrylic acid. In this case, a mass ratio can be set such that, in a total of 100 parts by mass, the content of (A) is in the range of about 10 parts by mass to about 80 parts by mass, for example, 20 parts by mass to 70 parts by mass, 20 parts by mass to 60 parts by mass, or 20 parts by mass to 50 parts by mass (for example, 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 20 parts by mass, 21 parts by mass, 22 parts by mass, 23 parts by mass, 24 parts by mass, 25 parts by mass, 26 parts by mass, 27 parts by mass, 28 parts by mass, 29 parts by mass, 30 parts by mass, 31 parts by mass, 32 parts by mass, 33 parts by mass, 34 parts by mass, 35 parts by mass, 36 parts by mass, 37 parts by mass, 38 parts by mass, 39 parts by mass, 40 parts by mass, 41 parts by mass, 42 parts by mass, 4...). 3 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight; and the content of (B) is in the range of about 10 parts by weight to about 80 parts by weight, for example, 20 parts by weight to 70 parts by weight, 30 parts by weight to 70 parts by weight, or 30 parts by weight to 60 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 3 7 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight The amounts are approximately 1 part by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, and 80 parts by weight, and the content of (C) is in the range of about 1 part by weight to about 30 parts by weight, for example, 5 parts by weight to 30 parts by weight or 5 parts by weight to 20 parts by weight (e.g., 1 part by weight, 2 parts by weight). (3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts).

[0213] The content of the core-shell binder in the coating can be in the range of about 0.01 wt% to about 30 wt%, for example about 5 wt% to about 30 wt%, for example 8 wt% to 25 wt%, 8 wt% to 20 wt%, or 10 wt% to 20 wt%. Within the above range, the effect of the diaphragm can be easily achieved.

[0214] linear adhesive The coating includes a linear binder. The linear binder can significantly increase adhesion to each of the positive and negative electrodes through interaction with the core-shell binder, and can also increase adhesion between the porous substrate, the heat-resistant layer, and the adhesive layer.

[0215] Linear adhesives may be or include water-based adhesives.

[0216] Linear adhesives have functional groups at their ends.

[0217] The functional group may be or may include adhesive functional groups.

[0218] The terminal functional groups of linear adhesives can be the same as the terminal functional groups of the shell of core-shell adhesives.

[0219] The terminal functional group is essentially the same as the terminal functional group described in the core-shell binder.

[0220] According to one example embodiment, the terminal functional group may be or include one or more combinations of -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2, and -SS- groups. The functional group having the -SS- group is the same as the functional group described in Formula 6 above.

[0221] The weight-average molecular weight of the linear binder can be in the range of about 500 g / mol to about 50,000 g / mol, for example, from 1,000 g / mol to 5,000 g / mol (e.g., 500 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 7500 g / mol, 8000 g / mol, 8500 g / mol, 9000 g / mol, 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol). Within the aforementioned range, it is capable of filling the empty spaces between fillers or filling the spaces between core-shell binders.

[0222] When a linear adhesive has terminal functional groups, there are no particular restrictions on the structural units included in the adhesive backbone.

[0223] According to one example embodiment, the backbone of the shell of the core-shell adhesive may be the same as or different from the backbone of the linear adhesive.

[0224] The main chain of a linear adhesive can be either straight or branched.

[0225] In one example, the main chain of the linear adhesive may include -O- , -BY 1 - , -NY 2 - , -(C=O)- , -C≡N、 -S- and -(O=S=O)- At least one of them or a combination thereof. Here, Y 1 and Y 2 Each can be independently hydrogen or substituted or unsubstituted C1-C. 10 alkyl.

[0226] In one example, the backbone of the linear adhesive may have at least one of the following: alkylene glycol-containing structural units, cyano-containing structural units, and structural units derived from (meth)acrylate or (meth)acrylic acid.

[0227] For example, the backbone of a linear binder can have structural units containing alkylene glycol groups. These alkylene glycol-containing structural units are the same as those described in Formula 1 and Formulas 1-1 to 1-3 above.

[0228] In linear adhesives, functional groups with -SS- groups can be directly attached to structural units containing alkylene glycol groups.

[0229] In linear adhesives, functional groups with -SS- groups can be bonded to structural units containing alkylene glycol groups via linker groups.

[0230] For example, the linker can be or includes a functional group in the main chain having at least one of carbon, oxygen, nitrogen and sulfur.

[0231] The linker can be substantially the same as the linkers described in Chemical Formulas 7-1 to 7-12 above.

[0232] For the method of bonding the linker to the structural unit containing the alkylene glycol group, refer to reaction schemes 1 to 11 above.

[0233] In one example, the linear adhesive may have one of the structures represented by chemical formulas I and II below: Chemical Formula I: R 11 -SSY 1 -XY 2 -SSR 11 .

[0234] In the above chemical formula I, X is or includes one of the units of chemical formula I above, or a combination thereof, Y 1 and Y 2Each is or includes one of the above chemical formulas 7-1 to 7-12 or combinations thereof, and R 11 It includes, or includes, substituted or unsubstituted C1-C 10 Alkyl or substituted or unsubstituted C6-C 10 Aryl, and Chemical Formula II: Y 3 -XY 1 -SSR 11 .

[0235] In chemical formula II above, X is one of the units of chemical formula I above, or a combination thereof, Y 1 Y is or includes one of the above chemical formulas 7-1 to 7-12 or combinations thereof. 3 It is hydrogen, hydroxyl, substituted or unsubstituted C1-C 10 Alkyl, substituted or unsubstituted C1-C 10 Alkoxy or substituted or unsubstituted C6-C 10 Aryl, and R 11 It includes, or includes, substituted or unsubstituted C1-C 10 Alkyl or substituted or unsubstituted C6-C 10 Aryl.

[0236] In one example, R 11 It may be or include C1-C5 alkyl groups substituted with amino groups or C6-C groups substituted with amino groups. 10 Aryl.

[0237] In one example, -SSR 11 It can be or include -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

[0238] In addition to core-shell and linear adhesives, the coating may also include an adhesive binder. For example, an adhesive binder may include acrylate compounds or derivatives thereof, diallyl phthalate compounds or derivatives thereof, polyimide compounds or derivatives thereof, or polyurethane compounds or derivatives thereof. For instance, an adhesive binder may be cross-linked polymethyl methacrylate.

[0239] In addition to core-shell binders, coatings may also include adhesives.

[0240] The adhesive may be or may include a heat-resistant adhesive (or a heat-resistant bonding adhesive).

[0241] The adhesive may be or include a non-core-shell adhesive but may not include a core-shell adhesive.

[0242] The heat-resistant adhesive may include a (meth)acrylic adhesive, which comprises structural units containing sulfonic acid groups. The (meth)acrylic adhesive may also include at least one of structural units derived from (meth)acrylates or (meth)acrylic acid, structural units containing cyano groups, and structural units derived from (meth)acrylamide.

[0243] The content of the heat-resistant binder in the coating can be in the range of about 1 wt% to about 25 wt%, for example, 1 wt% to 20 wt%, 1 wt% to 15 wt%, or 2 wt% to 15 wt%.

[0244] The coating may also include fillers.

[0245] The average particle size D50 of the filler can be about 0.4 μm or smaller, for example, 0.35 μm or smaller, 0.3 μm or smaller, or in the range of about 0.1 μm to about 0.3 μm. Within the above range, it can have the effect of improving heat resistance properties.

[0246] The surface of the filler may or may not be modified.

[0247] The filler may be or include, for example, inorganic fillers, organic fillers, organic-inorganic composite fillers, or combinations thereof. Inorganic fillers may include ceramic materials capable of improving heat resistance. Inorganic fillers may include at least one of, for example, metal oxides, quasi-metal oxides, metal fluorides, metal hydroxides, or combinations thereof. Inorganic fillers may include at least one of, for example, Al₂O₃, SiO₂, TiO₂, SnO₂, CeO₂, MgO, NiO, CaO, GaO, ZnO, ZrO₂, Y₂O₃, SrTiO₃, BaTiO₃, Mg(OH)₂, boehmite, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may include acrylic compounds, imide compounds, amide compounds, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may have a core-shell structure, but this disclosure is not limited thereto. For example, the filler may include boehmite.

[0248] The filler can have a spherical shape, a plate shape, a cubic shape, or no fixed shape. For example, the filler can have a cubic shape, and cubic filler can have a significantly lower thermal shrinkage rate as described above.

[0249] The filler may be included in a suitable or desired amount relative to the heat-resistant binder. According to one example embodiment, the heat-resistant binder and filler may be included in a mass ratio of about 1:10 to about 1:50, for example, 1:20 to 1:30. Within the above range, this can have the effect of improving heat resistance in the electrolyte.

[0250] The filler content in the coating can range from about 50 wt% to about 99 wt%, for example, 70 wt% to 99 wt%, 75 wt% to 99 wt%, 80 wt% to 99 wt%, 85 wt% to 99 wt%, 90 wt% to 99 wt%, or 95 wt% to 99 wt%. When the filler content is within the above range, desired or improved heat resistance, durability, oxidation resistance, and stability can be exhibited.

[0251] According to one example embodiment, the coating may be or comprise a single layer comprising a core-shell binder, a linear binder, a heat-resistant binder, and a filler. The coating may be formed from a composition comprising a core-shell binder, a linear binder, a heat-resistant binder, and a filler, or may comprise a composition comprising a core-shell binder, a linear binder, a heat-resistant binder, and a filler.

[0252] The coatings may each have a thickness in the range of about 0.01 μm to about 20 μm, and within the above range, they may have a thickness of 1 μm to 10 μm, 1 μm to 5 μm, or 1 μm to 3 μm.

[0253] According to another example embodiment, the coating may include: a heat-resistant layer comprising a heat-resistant adhesive and a filler; and an adhesive layer situated on the heat-resistant layer and comprising a core-shell adhesive and a linear adhesive. The heat-resistant layer may be formed of a composition comprising a heat-resistant adhesive and a filler but excluding the core-shell adhesive and the linear adhesive, or may comprise a composition comprising a heat-resistant adhesive and a filler but excluding the core-shell adhesive and the linear adhesive.

[0254] In the adhesive layer, core-shell and linear adhesives may be included in a weight ratio of about 2:1 to about 20:1, for example, 5:1 to 15:1 (e.g., 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1). Within the above range, the effect of improving adhesion to each of the positive and negative electrodes may be desired or improved.

[0255] Each heat-resistant layer may have a thickness ranging from about 0.01 μm to about 20 μm, and within the aforementioned range, may have a thickness ranging from about 1 μm to about 10 μm, or from 1 μm to 5 μm, or from 1 μm to 3 μm.

[0256] Each adhesive layer may have a thickness in the range of about 0.01 μm to about 20 μm, and within the range therema, it may have a thickness of 0.1 μm to 10 μm, 0.1 μm to 5 μm, or 0.2 μm to 1 μm.

[0257] The coating is located on at least one surface of the porous substrate.

[0258] The ratio of coating thickness to porous substrate thickness can be in the range of about 0.05 to about 0.5, for example, 0.05 to 0.4, 0.05 to 0.3, or 0.1 to 0.2. Within the above range, the diaphragm can exhibit desired or improved permeability, heat resistance, and adhesion. Here, when the coating is formed on only one surface of the porous substrate, "coating thickness" is the thickness of one coating layer, and when the coating is formed on both surfaces of the porous substrate, "coating thickness" is the total thickness of the two coating layers.

[0259] porous substrate The details of the porous substrate are substantially the same as those described in the description of the porous substrate used in the separator for the first rechargeable lithium battery. Therefore, a detailed description of the porous substrate is omitted.

[0260] Separators for rechargeable lithium-ion batteries can exhibit desired or improved permeability and can have permeability values, for example, less than about 200 seconds / 100cc, or for example, 190 seconds / 100cc or less, or 180 seconds / 100cc or less. That is, the permeability value of the separator can be less than about 40 seconds / 100cc per μm of thickness, for example, 30 seconds / 100cc or less per μm of thickness, or 25 seconds / 100cc or less per μm of thickness. Here, permeability represents the time (in seconds) it takes for 100cc of air to pass through a unit thickness of separator. Permeability per unit thickness can be obtained by measuring the permeability over the entire thickness of the separator and dividing the measured permeability by the thickness. Permeability can be measured by measuring the time (in seconds) it takes for 100cc of air to pass through the separator using a measuring device (EG01-55-1MR manufactured by Asahi Seiko).

[0261] A separator for a rechargeable battery can be formed by coating one or both surfaces of a porous substrate with a composition for forming a coating, drying the composition, and then curing the composition. Curing can be carried out using typical methods known to those skilled in the art.

[0262] Figure 3 This is a cross-sectional view showing a separator for a rechargeable lithium battery according to an example embodiment.

[0263] Reference Figure 3 The separator for a rechargeable lithium battery includes a porous substrate 1 and a coating 2 on each of two opposing surfaces of the porous substrate 1. The coating 2 is a laminate of a heat-resistant layer 5 and an adhesive layer 7. The heat-resistant layer 5 may include a filler 3 and a heat-resistant adhesive 4. The adhesive layer 7 may be located on the heat-resistant layer 5 and may include a core-shell adhesive 6 and a linear adhesive 8.

[0264] Figure 4 This is a cross-sectional view showing a separator for a rechargeable lithium battery according to another example embodiment.

[0265] Reference Figure 4 The separator for a rechargeable lithium battery includes a porous substrate 1 and a coating 2 disposed on two surfaces of the porous substrate 1. The coating 2 may include a filler 3, a heat-resistant binder 4, a core-shell binder 6, and a linear binder 8.

[0266] Separator for third rechargeable lithium batteries A separator for a rechargeable lithium-ion battery includes a porous substrate and a coating formed on at least one surface of the porous substrate. The coating includes a mixture of a core-shell binder and a linear binder, as well as fillers. The core-shell binder has a first adhesive functional group, and the linear binder has a second adhesive functional group.

[0267] The coating may comprise both a core-shell binder having a first adhesive functional group and a linear binder having a second adhesive functional group, thereby reducing the thermal shrinkage rate of the diaphragm and increasing its adhesion to each of the positive and negative electrodes. This is believed to be because the core-shell binder and the linear binder each interact with the filler, but this disclosure is not limited thereto. Specifically, this is believed to be because the contact area between the linear binder and the filler is increased due to the linear binder (particularly the second adhesive functional group of the linear binder), but this disclosure is not limited thereto.

[0268] The diaphragm may have a thermal shrinkage rate of about 13% or less in the mechanical direction (MD) and about 5% or less in the transverse direction (TD). Here, MD and TD are the same directions as the MD and TD of the porous substrate, respectively.

[0269] The adhesion force of the diaphragm to the positive electrode can be about 0.9 gf / mm or greater, and the adhesion force of the diaphragm to the negative electrode can be about 0.7 gf / mm or greater.

[0270] The first adhesive functional group of the core-shell binder and the second adhesive functional group of the linear binder can be the same. The same adhesive functional groups can interact with each other to increase the bonding between the core-shell binder and the linear binder, thereby further increasing the adhesion of the membrane to each of the positive and negative electrodes.

[0271] Core-shell binder The coating includes a core-shell binder. The separator has low resistance, which increases the dissociation of lithium ions and forms ion transport channels, and it exhibits high adhesion to each of the positive and negative electrodes. Therefore, the separator can increase the battery life at both room temperature and high temperature.

[0272] Core-shell binders can provide low resistance, high lithium-ion dissociation, ion transport channels, and high adhesion to each of the positive and negative electrodes.

[0273] In one example, the core-shell binder may be or include an aqueous adhesive. Therefore, the core-shell binder can be used in an aqueous solvent (e.g., water) to provide an aqueous coating, thereby allowing the fabrication of environmentally friendly membranes.

[0274] In one example, the core-shell binder may be or may include a particulate binder.

[0275] In one example, the average particle size D50 of the core-shell binder can be about 700 nm or smaller, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 3 The ranges from 70nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm, 530nm, 540nm, 550nm, 560nm, 570nm, 580nm, 590nm, 600nm, 610nm, 620nm, 630nm, 640nm, 650nm, 660nm, 670nm, 680nm, 690nm, 700nm, and from about 200nm to about 700nm, 300nm to 700nm, or 300nm to 600nm. Within these ranges, core-shell binders can be readily manufactured, and the permeability of the membrane can be increased. The average particle size D50 can be adjusted by controlling the reaction temperature and stirring speed of the core and / or shell during the preparation of the core-shell binder, but this disclosure is not limited thereto.

[0276] In the core-shell binder, the core content can range from about 40 wt% to about 90 wt%, for example, 50 wt% to 70 wt%, and the shell content can range from about 10 wt% to about 60 wt%, for example, 30 wt% to 50 wt%. Within the above ranges, the core-shell binder can have high mechanical strength, thereby increasing the strength of the diaphragm.

[0277] nuclear The core may be or include an organic core, and may include a first copolymer.

[0278] The details of the core are substantially the same as those described in the core-shell adhesive for the separator used in the first rechargeable lithium battery. Therefore, a detailed description of the core is omitted.

[0279] shell The shell surrounds the surface of the core and includes a second copolymer attached to the surface of the core.

[0280] The second copolymer has alkylene glycol-containing structural units and cyano-containing structural units, and has a first adhesive functional group at one end. The other end of the second copolymer can be bonded to the surface of the core. The alkylene glycol-containing structural units and the cyano-containing structural units can exist between the surface of the core and the first adhesive functional group.

[0281] The structural unit containing alkylene glycol groups can be or includes lithium-ion conducting units, and can form lithium-ion transport channels and reduce the resistance of the separator, thereby improving the battery life at room temperature and high temperature.

[0282] The cyano-containing structural unit can be or includes a lithium-ion conducting unit, and can form a lithium-ion transport channel and reduce the resistance of the separator, thereby improving the battery life at room temperature and high temperature.

[0283] According to one example embodiment, the second copolymer may have alkylene glycol-containing structural units and cyano-containing structural units in the main chain of the second copolymer.

[0284] The structural unit containing an alkylene glycol group can be represented by the above chemical formula 1, and the second copolymer can include one or more units of the above chemical formula 1.

[0285] The above chemical formula 1 can be or include one or more of the above chemical formulas 1-1, 1-2 and 1-3.

[0286] The structural unit containing an alkylene glycol group can be derived from at least one of ethylene glycol, n-propylene glycol, and propylene glycol carbonate. That is, the second copolymer can include units derived from at least one of PEG, polypropylene glycol, and polypropylene glycol carbonate.

[0287] The content of alkylene glycol-containing structural units relative to 100 mol% of repeating units in the second copolymer can range from about 15 mol% to about 85 mol%, 15 mol% to 75 mol%, 25 mol% to 85 mol%, 25 mol% to 70 mol%, 30 mol% to 75 mol%, or 30 mol% to 70 mol%. Within these ranges, the membrane can ensure desired or improved antioxidant properties and can exhibit adhesion, heat resistance, and breathability.

[0288] The cyano-containing structural unit can be represented by the above chemical formula 2, and the second copolymer can include one or more units of the above chemical formula 2.

[0289] The cyano-containing structural unit may be or includes structural units derived from, for example, (meth)acrylonitrile, olefin nitrile, (meth)acrylic cyanoalkyl ester, or 2-(ethoxy)alkane nitrile. Here, the olefin may be or includes C2-C 20 Olefins, C2-C 10 An olefin or a C2-C6 olefin, and the alkyl group may be or include C1-C6. 20 Alkyl, C1-C 10 Alkyl or C1-C6 alkyl. Furthermore, alkanes can be or include C1-C6 alkyl groups. 20 Alkanes, C1-C 10 Alkanes or C1-C6 alkanes.

[0290] Olefin nitrile may be or include, for example, allyl cyanide, 4-pentenonitrile, 3-pentenonitrile, 2-pentenonitrile, or 5-hexenonitrile. (Meth)acrylate cyanoalkyl ester may be or include, for example, at least one of (meth)acrylate methyl cyanoacrylate, (meth)acrylate ethyl cyanoacrylate, (meth)acrylate propyl cyanoacrylate, or (meth)acrylate octyl cyanoacrylate. 2-(ethoxy)alkane nitrile may be or include, for example, 2-(ethoxy)acetonitrile or 2-(ethoxy)propionitrile.

[0291] The content of cyano-containing structural units relative to 100 mol% of repeating units in the second copolymer can range from about 15 mol% to about 80 mol%, for example, 15 mol% to 70 mol%, 25 mol% to 80 mol%, 25 mol% to 65 mol%, 30 mol% to 70 mol%, or 30 mol% to 65 mol%. Within the above range, the membrane can ensure desired or improved antioxidant properties and can exhibit adhesion, heat resistance, and air permeability.

[0292] According to an example embodiment, the total content of alkylene glycol-containing structural units and cyano-containing structural units can be about 95 mol% or more relative to 100 mol% of repeating units in the second copolymer, for example, in the range of about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-described diaphragm effect can be easily achieved.

[0293] The second copolymer may also include structural units derived from (meth)acrylic acid or (meth)acrylate. The second copolymer may include structural units derived from (meth)acrylic acid or (meth)acrylate in its main chain. For example, the second copolymer may include structural units derived from (meth)acrylic acid.

[0294] Structural units derived from (meth)acrylic acid or (meth)acrylates can include lithium cations in the unit structure, thus providing lithium cations through a dissociation process. Therefore, the membrane can provide the effect of increasing lithium cation concentration and reducing resistance. Furthermore, the membrane can have carboxyl functional groups to further increase adhesion. In addition, the membrane can further increase adhesion to ensure high adhesion to the electrode and can provide desired or improved heat resistance, permeability, and oxidation resistance. Furthermore, dispersibility in compositions for coatings, including core-shell binders, can be improved.

[0295] In structural units derived from (meth)acrylates or (meth)acrylic acid, the (meth)acrylate can be or include a conjugate base of (meth)acrylic acid, a (meth)acrylate salt, or a derivative thereof. Structural units derived from (meth)acrylates or (meth)acrylic acid can be represented, for example, by chemical formulas 3, 4, or 5 above, or combinations thereof.

[0296] The content of structural units derived from (meth)acrylate or (meth)acrylic acid in the repeating units of the second copolymer can range from about 0.1 mol% to about 30 mol%, 0.1 mol% to 25 mol%, 1 mol% to 25 mol%, 1 mol% to 20 mol%, or 5 mol% to 20 mol%. Within the above ranges, the membrane can exhibit desired or improved adhesion, heat resistance, air permeability, and oxidation resistance.

[0297] As an example, structural units derived from (meth)acrylates or (meth)acrylic acid may include structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above, in which case the structural units represented by chemical formula 4 above and structural units represented by chemical formula 5 above may be included in a molar ratio ranging from about 10:1 to about 1:2 or from 10:1 to 1:1 or from 5:1 to 1:1.

[0298] According to one example embodiment, relative to 100 mol% of repeating units in the second copolymer, the total content of alkylene glycol-containing structural units, cyano-containing structural units, and structural units derived from (meth)acrylate or (meth)acrylic acid can be about 95 mol% or more, for example, in the range of about 95 mol% to about 100 mol% or 100 mol%. Within the above range, the above-described diaphragm effect can be easily achieved.

[0299] The second copolymer can be provided in various forms, such as alternating polymers with alternating structural units, random polymers with randomly distributed structural units, or grafted polymers in which some structural units are grafted.

[0300] The shell has a first adhesive functional group at one end.

[0301] The first adhesive functional group can be bonded to a structural unit containing an alkylene glycol group, a structural unit containing a cyano group, or a structural unit derived from (meth)acrylate or (meth)acrylic acid. In one example, the first adhesive functional group can be bonded to a structural unit containing an alkylene glycol group.

[0302] The first binding functional group can form chemical or physical bonds. For example, the first binding functional group can undergo hydrogen bonding or covalent reforming.

[0303] The first adhesive functional group may include oxygen, nitrogen or sulfur with high electronegativity, and may be or include one or more of the functional groups having, for example, -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2 and -SS- groups.

[0304] The first binding functional group may undergo metathesis and may include, for example, a -SS- group. For example, a functional group including a -SS- group can be represented by the above chemical formula 6.

[0305] In chemical formula 6 above, R 11 It may be or include C1-C5 alkyl groups substituted with amino groups or C6-C groups substituted with amino groups. 10 Aryl.

[0306] Functional groups including -SS-bases can be or include -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

[0307] The first adhesive functional group can be directly bonded to structural units containing alkylene glycol groups, structural units containing cyano groups, or structural units derived from (meth)acrylates or (meth)acrylic acid.

[0308] In another example, the first adhesive functional group can be bonded to a structural unit containing an alkylene glycol group, a structural unit containing a cyano group, or a structural unit derived from (meth)acrylate or (meth)acrylic acid via a linker.

[0309] The linker can be or includes a functional group in the main chain having at least one of carbon, oxygen, nitrogen and sulfur.

[0310] The linker can be represented by chemical formulas 7-1 to 7-12 above.

[0311] Linking groups can be bonded to structural units containing alkylene glycol groups.

[0312] The linker can be bonded to structural units containing alkylene glycol groups using typical methods known to those skilled in the art. For example, the reaction schemes 1 to 11 above can be referred to.

[0313] The second copolymer can be prepared by polymerizing a monomer that provides a cyano-containing structural unit (e.g., a monomer that provides a unit of chemical formula 2 above) and a monomer that provides an alkylene glycol-containing structural unit (e.g., a monomer that provides a unit of chemical formula 1 above), and then introducing a first adhesive functional group at its end.

[0314] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of alkylene glycol-containing structural units having a first adhesive functional group at its end and (B) a monomer providing cyano-containing structural units. In this case, the mass ratio may be set such that, in a total of 100 parts by mass of (A) and (B), the content of (A) is in the range of about 10 parts by mass to about 90 parts by mass, for example, 20 parts by mass to 80 parts by mass, 30 parts by mass to 70 parts by mass, or 30 parts by mass to 50 parts by mass (e.g., 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 2...). 0 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight 48 units, 49 units, 50 units, 51 units, 52 units, 53 units, 54 units, 55 units, 56 units, 57 units, 58 units, 59 units, 60 units, 61 units, 62 units, 63 units, 64 units, 65 units, 66 units, 67 units, 68 units, 69 units, 70 units, 71 units, 72 units, 73 units, 74 units, 7 5 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, 85 parts by weight, 86 parts by weight, 87 parts by weight, 88 parts by weight, 89 parts by weight, and 90 parts by weight), and the content of (B) is in the range of about 10 parts by weight to about 90 parts by weight, for example, 20 parts by weight to 80 parts by weight, or 30 parts by weight to 70 parts by weight, or 50 parts by weight to 70 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight (Quantities: 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, 66 parts, 67 parts, 68 parts, 69 parts, 70 parts, 71 parts, 72 parts, 73 parts, 74 parts, 75 parts, 76 parts, 77 parts, 78 parts, 79 parts, 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts).

[0315] The second copolymer may be or include a copolymer of monomer mixtures comprising (A) a prepolymer of a structural unit containing an alkylene glycol group having a first adhesive functional group at its end, (B) a monomer providing a structural unit containing a cyano group, and (C) a (meth)acrylate or (meth)acrylic acid. In this case, a mass ratio can be set such that, in a total of 100 parts by mass of (A), (B), and (C), the content of (A) is in the range of about 10 parts by mass to about 80 parts by mass, for example, 20 parts by mass to 70 parts by mass, 20 parts by mass to 60 parts by mass, or 20 parts by mass to 50 parts by mass (for example, 10 parts by mass, 11 parts by mass, 12 parts by mass, 13 parts by mass, 14 parts by mass, 15 parts by mass, 16 parts by mass, 17 parts by mass, 18 parts by mass, 19 parts by mass, 20 parts by mass, 21 parts by mass, 22 parts by mass, 23 parts by mass, 24 parts by mass, 25 parts by mass, 26 parts by mass, 27 parts by mass, 28 parts by mass, 29 parts by mass, 30 parts by mass, 31 parts by mass, 32 parts by mass, 33 parts by mass, 34 parts by mass, 35 parts by mass, 36 parts by mass, 37 parts by mass, 38 parts by mass, 39 parts by mass, 40 parts by mass, 41 parts by mass, 4 2 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight, 65 parts by weight, 66 parts by weight, 6 7 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight; and the content of (B) is in the range of about 10 parts by weight to about 80 parts by weight, for example, 20 parts by weight to 70 parts by weight, 30 parts by weight to 70 parts by weight, or 30 parts by weight to 60 parts by weight (e.g.,10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 3 7 parts by weight, 38 parts by weight, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight, 54 parts by weight, 55 parts by weight, 56 parts by weight, 57 parts by weight, 58 parts by weight, 59 parts by weight, 60 parts by weight, 61 parts by weight, 62 parts by weight, 63 parts by weight, 64 parts by weight The amounts are approximately 1 part by weight, 65 parts by weight, 66 parts by weight, 67 parts by weight, 68 parts by weight, 69 parts by weight, 70 parts by weight, 71 parts by weight, 72 parts by weight, 73 parts by weight, 74 parts by weight, 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, and 80 parts by weight, and the content of (C) is in the range of about 1 part by weight to about 30 parts by weight, for example, 5 parts by weight to 30 parts by weight or 5 parts by weight to 20 parts by weight (e.g., 1 part by weight, 2 parts by weight). (3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts).

[0316] The content of the core-shell binder in the coating can be in the range of about 0.01 wt% to about 30 wt%, for example, about 5 wt% to about 30 wt%, for example, 8 wt% to 25 wt%, 8 wt% to 20 wt%, or 10 wt% to 20 wt% (e.g., 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0 (6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%). Within the above range, the effect of a diaphragm can be easily achieved.

[0317] linear adhesive The coating includes a linear binder. The linear binder can interact with the filler to reduce the thermal shrinkage rate of the diaphragm. Furthermore, the linear binder can interact with the core-shell binder to significantly increase adhesion to each of the positive and negative electrodes.

[0318] Linear binders can be or include water-based adhesives. Therefore, linear binders can increase the eco-friendliness of the membrane by allowing the use of water-based solvents to manufacture the coating.

[0319] Linear adhesives may have a second adhesive functional group and may be or include water-based adhesives.

[0320] The second adhesive functional group can be or include one or more combinations of functional groups having -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2, and -SS- groups. The functional group having the -SS- group is the same as the functional group described in Chemical Formula 6 above.

[0321] In one example, the second adhesive functional group of the linear adhesive can be the same as the first adhesive functional group of the shell of the core-shell adhesive.

[0322] The weight-average molecular weight of the linear binder can be in the range of about 500 g / mol to about 50,000 g / mol, for example, from 1,000 g / mol to 5,000 g / mol (e.g., 500 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol, 6000 g / mol, 6500 g / mol, 7000 g / mol, 7500 g / mol, 8000 g / mol, 8500 g / mol, 9000 g / mol, 10000 g / mol, 20000 g / mol, 30000 g / mol, 40000 g / mol, 50000 g / mol). Within the aforementioned range, it can fill the empty spaces between fillers or the spaces between core-shell binders. The weight-average molecular weight can be obtained, for example, by gel permeation chromatography, in polystyrene equivalents.

[0323] When a linear adhesive has a second adhesive functional group, there are no particular restrictions on the structural units included in the main chain of the linear adhesive.

[0324] According to one example embodiment, the backbone of the linear adhesive may be the same as or different from the backbone of the shell of the core-shell adhesive.

[0325] The main chain of a linear adhesive can be either straight or branched.

[0326] In one example, the main chain of the linear adhesive may include -O- , -BY 1 - , -NY 2 - , -(C=O)- , -C≡N、 -S- and -(O=S=O)- At least one of them or a combination thereof. Here, Y 1 and Y 2 Each can be independently hydrogen or substituted or unsubstituted C1-C. 10 alkyl.

[0327] In one example, the backbone of the linear adhesive may have at least one of the following: alkylene glycol-containing structural units, cyano-containing structural units, and structural units derived from (meth)acrylate or (meth)acrylic acid.

[0328] For example, the backbone of a linear binder can have structural units containing alkylene glycol groups. These alkylene glycol-containing structural units are the same as those described in Formula 1 and Formulas 1-1 to 1-3 above.

[0329] In linear adhesives, functional groups with -SS- groups can be directly attached to structural units containing alkylene glycol groups.

[0330] In linear adhesives, functional groups with -SS- groups can be bonded to structural units containing alkylene glycol groups via linker groups.

[0331] For example, the linker may be or include a functional group having at least one of carbon, oxygen, nitrogen and sulfur in the main chain.

[0332] The linker can be substantially the same as the linkers described in Chemical Formulas 7-1 to 7-12 above.

[0333] For the method of bonding the linker to the structural unit containing the alkylene glycol group, refer to reaction schemes 1 to 11 above.

[0334] In one example, the linear adhesive may have the structure of either chemical formula I or chemical formula II above.

[0335] In one example, R 11 It may be or include C1-C5 alkyl groups substituted with amino groups or C6-C groups substituted with amino groups. 10 Aryl.

[0336] In one example, -SSR 11 It can be -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

[0337] The content of the linear binder in the coating can be in the range of about 0.01 wt% to about 30 wt%, for example, about 5 wt% to about 30 wt%, for example, 8 wt% to 25 wt%, 8 wt% to 20 wt%, or 10 wt% to 20 wt% (e.g., 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0 (6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%). Within the above range, the effect of a diaphragm can be easily achieved.

[0338] In one example, the coating may include a core-shell binder and a linear binder in a weight ratio of about 3:1 to about 15:1, for example, from 3:1 to 12:1 (e.g., 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1). Within the above range, the diaphragm effect can be easily achieved.

[0339] Adhesive adhesive In addition to core-shell and linear adhesives, the coating may also include an adhesive binder. For example, the adhesive binder may include at least one of acrylate compounds or derivatives thereof, diallyl phthalate compounds or derivatives thereof, polyimide compounds or derivatives thereof, or polyurethane compounds or derivatives thereof. For example, the adhesive binder may be cross-linked polymethyl methacrylate.

[0340] Heat-resistant adhesive In addition to core-shell and linear adhesives, the coating may also include heat-resistant adhesives. Heat-resistant adhesives can further reduce the thermal shrinkage rate of the diaphragm.

[0341] The heat-resistant adhesive may be or include a non-core-shell adhesive but may not include a core-shell adhesive.

[0342] The heat-resistant adhesive may include a (meth)acrylic adhesive, which comprises structural units containing sulfonic acid groups. The (meth)acrylic adhesive may also include at least one of structural units derived from (meth)acrylates or (meth)acrylic acid, structural units containing cyano groups, and structural units derived from (meth)acrylamide.

[0343] The content of the heat-resistant binder in the coating can be in the range of about 2 wt% to about 15 wt%, for example, 2 wt% to 8 wt% or 4 wt% to 6 wt% (e.g., 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%). Within the above range, the thermal shrinkage rate of the diaphragm can be reduced without affecting the adhesion of the diaphragm to the positive and negative electrodes.

[0344] In one example, relative to 100 parts by weight of the heat-resistant binder, the total amount of the core-shell binder and the linear binder can be in the range of about 2 parts by weight to about 30 parts by weight, for example, 2 parts by weight to 20 parts by weight or 5 parts by weight to 15 parts by weight (e.g., 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight, 30 parts by weight). Within the above range, the effect of the diaphragm can be easily achieved.

[0345] filler The filler can interact with linear binders and core-shell binders to reduce the thermal shrinkage rate of the diaphragm.

[0346] Fillers can have hydroxyl groups on their surface. Hydroxyl groups can enhance the interaction between the filler and linear binders and core-shell binders.

[0347] Hydroxyl groups can be formed in the packing material itself (pre-formation) or introduced into the packing material through additional post-treatment (such as surface modification) (post-formation). For example, in the case of pre-formation, the manufacturability of the membrane can be improved.

[0348] The filler can have a particle size D100 of about 700 nm or smaller. Within the above range, the filler can be readily included in a coating containing a core-shell binder to enhance the diaphragm effect. For example, the particle size D100 can be in the range of about 0.3 nm to about 0.6 nm.

[0349] The filler may have an average particle size D50 of about 400 nm or less, for example, 350 nm or less, 300 nm or less, or in the range of about 100 nm to about 300 nm. Within the above range, the thermal stability can be increased because the filler has a particle size in the appropriate or desired range compared to the core-shell binder, and the interaction with the linear binder can also be increased due to the increased surface area, thereby further improving the heat resistance.

[0350] The filler may be or include, for example, inorganic fillers, organic fillers, organic-inorganic composite fillers, or combinations thereof. Inorganic fillers may include ceramic materials capable of improving heat resistance. Inorganic fillers may include at least one of, for example, metal oxides, quasi-metal oxides, metal fluorides, metal hydroxides, or combinations thereof. Inorganic fillers may include at least one of, for example, Al₂O₃, SiO₂, TiO₂, SnO₂, CeO₂, MgO, NiO, CaO, GaO, ZnO, ZrO₂, Y₂O₃, SrTiO₃, BaTiO₃, Mg(OH)₂, boehmite, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may include acrylic compounds, imide compounds, amide compounds, or combinations thereof, but this disclosure is not limited thereto. Organic fillers may have a core-shell structure, but this disclosure is not limited thereto.

[0351] For example, the filler can be boehmite. Because boehmite has hydroxyl groups, such as γ-AlOOH, on its outermost surface, it can interact with linear binders and does not require a separate hydroxyl group introduction process, thus improving the membrane manufacturing process.

[0352] The filler can have a spherical shape, a plate shape, a cubic shape, or no fixed shape. For example, the filler can have a cubic shape, and cubic filler can have a significantly lower thermal shrinkage rate as described above.

[0353] In contrast to linear adhesives, fillers may be included in appropriate or desired amounts.

[0354] According to one example embodiment, linear binders and fillers may be included in a mass ratio ranging from about 1:2000 to about 1:100, for example, 1:2000, 1:1900, 1:1800, 1:1700, 1:1600, 1:1500, 1:1400, 1:1300, 1:1200, 1:1100, 1:1000, 1:900, 1:800, 1:700, 1:600, 1:500, 1:400, 1:300, 1:200, 1:100, 1:1000 to 1:200. Within the above range, it is possible to promote the improvement of the thermal shrinkage rate of the diaphragm and reduce or prevent the reduction of the diaphragm's adhesiveness.

[0355] The filler can be included in a suitable or desired amount relative to the core-shell binder. According to one example embodiment, the core-shell binder and filler can be included in a mass ratio ranging from about 1:1,000 to about 1:50, for example, 1:1000, 1:950, 1:900, 1:850, 1:800, 1:750, 1:700, 1:650, 1:600, 1:550, 1:500, 1:450, 1:400, 1:350, 1:300, 1:250, 1:200, 1:150, 1:100, 1:50, 1:500 to 1:100. Within the above range, it is possible to promote an improvement in the thermal shrinkage rate of the diaphragm and also reduce or prevent an increase in the diaphragm's permeability.

[0356] In one example, filler may be included in an appropriate or desired amount relative to the total amount of heat-resistant adhesive, core-shell adhesive, and linear adhesive. The weight ratio of filler to the total amount of heat-resistant adhesive, core-shell adhesive, and linear adhesive may be in the range of about 10:1 to about 50:1, for example, 10:1 to 40:1 or 10:1 to 30:1 (e.g., 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 2...). The ratios of the membrane's thermal shrinkage rate (3:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, 36:1, 37:1, 38:1, 39:1, 40:1, 41:1, 42:1, 43:1, 44:1, 45:1, 46:1, 47:1, 48:1, 49:1, and 50:1) are within the above ranges. These ratios can promote the improvement of the membrane's thermal shrinkage rate and also reduce or prevent an increase in the membrane's air permeability.

[0357] The filler content in the coating can range from about 50 wt% to about 99 wt%, for example, 70 wt% to 99 wt%, 75 wt% to 99 wt%, 80 wt% to 99 wt%, 85 wt% to 99 wt%, 90 wt% to 99 wt%, or 95 wt% to 99 wt%. When the filler content is within the above range, desired or improved heat resistance, durability, oxidation resistance, and stability can be exhibited.

[0358] The coating may be or comprise a single layer formed by or containing a composition for coating, the composition for coating including a core-shell binder, a linear binder, and a filler.

[0359] The coating may be or may comprise a single layer formed by or containing a composition for coating, the composition for coating including a core-shell binder, a linear binder, a filler, and a heat-resistant binder.

[0360] The coatings may each have a thickness in the range of about 0.01 μm to about 20 μm, and within the above range, they may have a thickness in the range of about 1 μm to about 10 μm, or 1 μm to 5 μm, or 1 μm to 3 μm.

[0361] The coating is located on at least one surface of the porous substrate.

[0362] The ratio of coating thickness to porous substrate thickness can be in the range of about 0.05 to about 0.5, for example, 0.05 to 0.4, 0.05 to 0.3, or 0.1 to 0.2. Within the above range, the diaphragm can exhibit desired or improved permeability, heat resistance, and adhesion. Here, when the coating is formed on only one surface of the porous substrate, "coating thickness" is the thickness of one coating layer, and when the coating is formed on both surfaces of the porous substrate, "coating thickness" is the total thickness of the two coating layers.

[0363] porous substrate The details of the porous substrate are substantially the same as those described in the separator for the first rechargeable lithium battery. Therefore, a detailed description of the porous substrate is omitted.

[0364] Separators for rechargeable lithium-ion batteries can exhibit desired or improved permeability and can have permeability values, for example, less than about 200 seconds / 100cc, or for example, 190 seconds / 100cc or less, or 180 seconds / 100cc or less. That is, the permeability value of the separator can be less than about 40 seconds / 100cc per μm of thickness, for example, 30 seconds / 100cc or less per μm of thickness, or 25 seconds / 100cc or less per μm of thickness. Here, permeability represents the time (in seconds) it takes for 100cc of air to pass through a unit thickness of separator. Permeability per unit thickness can be obtained by measuring the permeability over the entire thickness of the separator and dividing the measured permeability by the thickness. Permeability can be measured by measuring the time (in seconds) it takes for 100cc of air to pass through the separator using a measuring device (EG01-55-1MR manufactured by Asahi Seiko).

[0365] A separator for a rechargeable battery according to an example embodiment can be formed by coating one or both surfaces of a porous substrate with a composition for forming a coating, drying the composition, and then curing the composition. Curing can be performed using typical methods known to those skilled in the art.

[0366] Figure 5 This is a cross-sectional view showing a separator for a rechargeable lithium battery according to an example embodiment.

[0367] Reference Figure 5 The separator for a rechargeable lithium battery includes a porous substrate 1 and coatings 2 on two surfaces of the porous substrate 1. The coatings 2 may include fillers 3, heat-resistant binders 4, linear binders 8, and core-shell binders 6.

[0368] Rechargeable lithium batteries According to one example embodiment, a rechargeable lithium battery includes a separator, a positive electrode, and a negative electrode for the rechargeable lithium battery.

[0369] The separator used in rechargeable lithium batteries is described above. The separator for rechargeable lithium batteries can be located between the positive and negative electrodes.

[0370] positive electrode The positive electrode for a rechargeable lithium battery may include a current collector and a layer of positive electrode active material on the current collector. The positive electrode active material layer may include positive electrode active material and may also include a binder and / or conductive material. For example, the positive electrode may also include additives that can constitute a sacrificial positive electrode.

[0371] Positive electrode active material The positive electrode active material may include compounds capable of intercalating and deintercalating lithium (lithiation intercalation compounds). For example, at least one of the composite oxides of lithium and metals such as or including at least one of cobalt, manganese, nickel, and combinations thereof may be used.

[0372] The composite oxide can be or includes lithium transition metal composite oxides. Examples of composite oxides may include at least one of lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free lithium nickel manganese oxides, or combinations thereof.

[0373] As an example, the following compounds, represented by any of the following chemical formulas, can be used. Li a A 1-b X b O 2- c D c (0.90≤a≤1.8, 0≤b≤0.5 and 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 and 0≤c≤0.05); Li aNi 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 and 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 and 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 and 0≤e≤0.1); Li a NiG b O2 (0.90≤a≤1.8 and 0.001≤b≤0.1); Li a CoG b O2 (0.90≤a≤1.8 and 0.001≤b≤0.1); Li a Mn 1-b G b O2 (0.90≤a≤1.8 and 0.001≤b≤0.1); Li a Mn2G b O4 (0.90≤a≤1.8 and 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8 and 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); or Li a FePO4 (0.90≤a≤1.8).

[0374] In the above chemical formula, A is or includes at least one of Ni, Co, Mn, or combinations thereof; X is or includes at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or combinations thereof; D is or includes at least one of O, F, S, P, or combinations thereof; G is or includes at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or combinations thereof; and L 1 It is or includes at least one of Mn, Al, or combinations thereof.

[0375] The positive electrode active material can be, or includes, for example, a high-nickel positive electrode active material, based on 100 mol% of metal other than lithium in a lithium transition metal complex oxide. The nickel content of the high-nickel positive electrode active material is greater than or equal to about 80 mol%, greater than or equal to about 85 mol%, greater than or equal to about 90 mol%, greater than or equal to about 91 mol%, or greater than or equal to about 94 mol% and less than or equal to about 99 mol%. High-nickel positive electrode active materials can achieve high capacity and can be applied to high-capacity, high-density rechargeable lithium batteries.

[0376] Based on a 100 wt% positive electrode active material layer, the amount of positive electrode active material can range from about 90 wt% to about 99.5 wt%. Based on a 100 wt% positive electrode active material layer, the amounts of binder and conductive material can each independently range from about 0.5 wt% to about 5 wt%.

[0377] The binder causes the positive electrode active material particles to adhere to each other and to adhere the positive electrode active material to the current collector. As a non-limiting example, examples of binders may include at least one of polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, nylon, etc.

[0378] Conductive materials can impart electrical conductivity (e.g., electroconductivity) to electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in rechargeable lithium batteries) and conducts electrons can be used in the battery. Examples of conductive materials may include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials, including at least one of copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0379] Al can be used as a current collector, but current collectors are not limited to this.

[0380] negative electrode The negative electrode for a rechargeable lithium battery may include a current collector and a layer of negative electrode active material on the current collector. The negative electrode active material layer may include a negative electrode active material and may also include a binder and / or a conductive material (e.g., an electrically conductive material).

[0381] For example, the negative electrode active material layer may include a negative electrode active material in the range of about 90 wt% to about 99 wt%, a binder in the range of about 0.5 wt% to about 5 wt%, and a conductive material in the range of about 0 wt% to about 5 wt%.

[0382] Negative electrode active material The negative electrode active material may include at least one of a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, a lithium metal alloy, a material capable of doping / de-doping lithium, or a transition metal oxide.

[0383] The material capable of reversibly intercalating / deintercalating lithium ions may include a carbon-based negative electrode active material, such as crystalline carbon, amorphous carbon, or a combination thereof. Crystalline carbon may be graphite, such as natural graphite or artificial graphite in an amorphous shape, flaky shape, lamellar shape, spherical shape, or fibrous shape. Amorphous carbon may be or include at least one of soft carbon, hard carbon, mesophase pitch carbonized product, calcined coke, etc.

[0384] The lithium metal alloy includes an alloy of lithium and a metal such as or including at least one of Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0385] The material capable of doping / de-doping lithium may be or include a Si-based negative electrode active material or a Sn-based negative electrode active material. The Si-based negative electrode active material may include silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2), a Si-Q alloy (where Q is or includes at least one of an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element (excluding Si), a Group 15 element, a Group 16 element, a transition metal, a rare earth element, and a combination thereof). The Sn-based negative electrode active material may include at least one of Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0386] The silicon-carbon composite may be or include a composite of silicon and amorphous carbon. According to an exemplary embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) assembled from primary silicon particles, and an amorphous carbon coating (shell) on the surface of the secondary particles. Amorphous carbon may also be between the primary silicon particles. For example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in the amorphous carbon matrix.

[0387] The silicon-carbon composite may also include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles, and an amorphous carbon coating on the surface of the core.

[0388] Si-based or Sn-based negative electrode active materials can be used in combination with carbon-based negative electrode active materials.

[0389] Binders can enable the negative electrode active material particles to adhere to each other and to the negative electrode active material to the current collector. Binders can include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0390] Non-aqueous adhesives may include at least one of polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0391] The waterborne adhesive may be or include at least one of styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0392] When using an aqueous binder as the negative electrode binder, it may also include a cellulose compound capable of imparting viscosity. The cellulose compound may include at least one of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may include at least one of Na, K, or Li.

[0393] Dry adhesives can be or include polymeric materials capable of being fibrous. For example, dry adhesives can be or include at least one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or combinations thereof.

[0394] Conductive materials can impart electrical conductivity (e.g., electroconductivity) to electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in a rechargeable lithium battery) and conducts electrons can be used in the battery. Non-limiting examples of conductive materials may include: carbon-based materials, such as at least one of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials, including at least one of copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers, such as polyphenylene derivatives; or mixtures thereof.

[0395] The negative electrode current collector may include at least one of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0396] Rechargeable lithium batteries may also include an electrolyte solution.

[0397] Electrolyte solution Electrolyte solutions used in rechargeable lithium batteries may include non-aqueous organic solvents and lithium salts.

[0398] Non-aqueous organic solvents can serve as media for transporting ions that participate in the electrochemical reactions of a battery.

[0399] Non-aqueous organic solvents may be or include at least one of carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents, or combinations thereof.

[0400] Carbonate solvents may include at least one of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butyl carbonate (BC).

[0401] Ester solvents may include at least one of the following: methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, caprolactone, etc.

[0402] Ether solvents may include at least one of dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. Additionally, ketone solvents may include cyclohexanone, etc. Alcohol solvents may include ethanol, isopropanol, etc. Aprotic solvents may include at least one of the following: nitriles, such as R-CN (wherein R is a C2 to C20 straight-chain, branched, or cyclic hydrocarbon group, and may include double bonds, aromatic rings, or ether bonds, etc.); amides, such as dimethylformamide; dioxolane, such as 1,3-dioxolane, 1,4-dioxolane, etc.; sulfolane; etc.

[0403] Non-aqueous organic solvents can be used alone or in combination of two or more.

[0404] Furthermore, when using carbonate solvents, cyclic carbonates and chain carbonates can be mixed together, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio ranging from about 1:1 to about 1:9.

[0405] Lithium salts dissolved in organic solvents supply lithium ions in batteries, enabling rechargeable lithium batteries to operate essentially and improving lithium ion transport between the positive and negative electrodes. 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, and LiN(C x F 2x+1 SO2)(C y F 2y+1 At least one of the following: (SO2) (where x and y are integers in the range of 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate (LiDBOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0406] Rechargeable lithium batteries can be classified according to their shape as cylindrical batteries, prismatic batteries, pouch batteries, or coin-shaped batteries, etc.

[0407] Figures 6 to 9 This is a schematic diagram illustrating a rechargeable lithium battery according to an example embodiment. Figure 6 A cylindrical battery is shown. Figure 7 A prismatic battery is shown, and Figure 8 and Figure 9 A pouch-type battery is shown. (See reference) Figures 6 to 9 The rechargeable lithium battery 100 may include an electrode assembly 40 and a housing 50. The electrode assembly 40 includes a separator 30 between a positive electrode 10 and a negative electrode 20, and the electrode assembly 40 is housed within the housing 50. The positive electrode 10, the negative electrode 20, and the separator 30 may be impregnated with an electrolyte (not shown). Figure 6 As shown, the rechargeable lithium battery 100 may include a sealing member 60 of the sealed housing 50. Figure 7 In this context, the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12 connected to the positive electrode lead connector 11, a negative electrode lead connector 21, and a negative electrode terminal 22 connected to the negative electrode lead connector 21. For example... Figure 8 and Figure 9 As shown, the rechargeable lithium battery 100 may include Figure 9 The electrode terminal 70 shown, or for example Figure 8 The positive electrode terminal 71 and negative electrode terminal 72 shown herein form an electrical path for guiding the current generated in the electrode assembly 40 to the outside of the rechargeable lithium battery 100.

[0408] As a non-limiting example, the rechargeable lithium battery according to the example embodiment can be used in, for example, automobiles, mobile phones and / or various types of electrical devices.

[0409] Examples and comparative examples of this disclosure are described below. However, the following examples are merely examples of this disclosure, and this disclosure is not limited to these examples.

[0410] Example 1 (1) Preparation of core-shell binder 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0411] Separately, 41.7 g of divinylbenzene, 53.9 g of acrylonitrile, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and the mixture was then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0412] Separately, 29.4 g of PEG (maleimide-polyethylene glycol-SS-CH2CH2-NH2 (MAL-PEG-SS-CH2CH2-NH2) manufactured by CD Bioparticles), 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes. This mixture was then added to the first solution, and the reaction was maintained at room temperature for 24 hours to prepare a core-shell binder having the shell of the following chemical formula 8. The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0413] Chemical formula 8:

[0414] (x and y are the number of moles in each unit).

[0415] (2) Manufacturing of the diaphragm Acrylic binder (10 wt% in distilled water) and boehmite (average particle size D50: 0.2 μm, cubic shape) as filler were mixed at a mass ratio of 1:20 (acrylic binder: filler) based on solid content, added to an aqueous solvent, and milled and dispersed using a bead mill at 25°C for 30 minutes to prepare a dispersion.

[0416] Poly(acrylic acid-co-lithium acrylate-co-acrylamide-co-2-acrylamido-2-methylpropanesulfonate) with a molar ratio of acrylic acid + lithium acrylate, acrylamide and lithium 2-acrylamido-2-methylpropanesulfonate of 10:85:5 was used as an acrylic binder.

[0417] The dispersion was applied to each of the two opposing surfaces of a porous polyethylene fabric (12 μm thick, 120 sec / 100 cc breathability) using a die-coating method to a thickness of 1.5 μm, and then dried and cured in an oven at 80 °C for 16 hours to form a heat-resistant layer.

[0418] The coating solution was prepared by mixing 90 parts by weight of deionized (DI) water and 10 parts by weight of the prepared core-shell binder.

[0419] The coating solution is applied to each of the two opposing surfaces of the formed heat-resistant layer using a bar coating method to a thickness of 0.5 μm, and then stored in an oven at 50°C for 1 hour to form an adhesive layer, thereby manufacturing a separator for lithium rechargeable batteries.

[0420] Example 2 The membrane was manufactured in the same manner as in Example 1, except that the proportions of acrylonitrile and PEG in the total amount of acrylonitrile and PEG were varied as shown in Table 1 below when the core-shell binder was prepared in Example 1.

[0421] Example 3 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0422] Separately, 41.7 g of divinylbenzene, 45.8 g of acrylonitrile, 12.5 g of lithium acrylate, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0423] Separately, 25.0 g of PEG (MAL-PEG-SS-CH2CH2-NH2 manufactured by CD Bioparticles) with an adhesive functional group at one end, 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes, then added to the first solution. The reaction was then maintained for 24 hours to prepare a core-shell binder having a shell of the following chemical formula 9. The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0424] Chemical formula 9:

[0425] (x, y, z represent the number of moles in each unit).

[0426] Except for using the prepared core-shell binder, the diaphragm is manufactured in the same manner as in Example 1.

[0427] Example 4 The membrane was manufactured in the same manner as in Example 3, except that when the core-shell binder was prepared in Example 3, the ratio of acrylonitrile, PEG with adhesive functional groups at one end, and lithium acrylate in the total amount was changed as shown in Table 1 below.

[0428] Comparison Example 1 The diaphragm is manufactured in the same manner as in Example 1, except that: instead of the PEG with adhesive functional groups at one end in Example 1, a PEG without adhesive functional groups at one end is used, and a core-shell binder comprising a shell without adhesive functional groups at one end is used.

[0429] Comparison Example 2 The membrane is manufactured in the same manner as in Example 3, except that, instead of using PEG with adhesive functional groups at one end in Example 3, a core-shell binder comprising a shell having structural units derived from acrylonitrile and lithium acrylate is used.

[0430] Compare Example 3 The diaphragm is manufactured in the same manner as in Example 3, except that: instead of the PEG with adhesive functional groups at one end as in Example 3, a core-shell binder comprising a shell without adhesive functional groups at one end is used.

[0431] Compare Example 4 The membrane is manufactured in the same manner as in Example 3, except that, in the absence of acrylonitrile, a core-shell binder is used, comprising a shell of PEG having units derived from lithium acrylate and adhesive functional groups at one end thereto.

[0432] Compare Example 5 The membrane is manufactured in the same manner as in Example 3, except that: instead of acrylonitrile, PEG without adhesive functional groups at one end is used instead of PEG with adhesive functional groups at one end, and a core-shell binder comprising units having units derived from PEG and lithium acrylate is used.

[0433] The physical properties described in Table 1 below are evaluated for the diaphragms manufactured according to the example and comparative examples.

[0434] (1) Air permeability (unit: seconds / 100°C) For the diaphragms manufactured in the example and comparative examples, the air permeability was measured by measuring the time (in seconds) it took for 100cc of air to pass through the diaphragm using a measuring device (EG01-55-1MR manufactured by Asahi Seiko). The air permeability was measured twice to obtain an average value.

[0435] Air permeability measurement equipment setting conditions: Measured pressure: 0.5 kg / cm 2 Cylinder pressure: 2.5 kg / cm² 2 Set time: 10 seconds.

[0436] (2) Wet adhesion force to the positive electrode and wet adhesion force to the negative electrode (unit: gf / mm) The separators for rechargeable lithium batteries in each example and comparative example were cut into 3cm × 8cm dimensions to prepare samples.

[0437] A positive electrode slurry was prepared by mixing 97 wt% LiCoNiAl as the positive electrode active material, 1.5 wt% carbon nanotubes as the conductive material, and 1.5 wt% polyvinyl fluoride and adding water.

[0438] The prepared positive electrode slurry is coated onto aluminum foil, dried, and rolled to manufacture the positive electrode.

[0439] A negative electrode slurry was prepared by mixing 97.4 wt% of a negative electrode active material, 1.0 wt% of carboxymethyl cellulose, 1.5 wt% of styrene-butadiene rubber, and 0.1 wt% of carbon nanotubes as a conductive material. A silicon-based negative electrode active material was used. The prepared negative electrode slurry was coated with copper foil, dried, and rolled to manufacture the negative electrode.

[0440] The fabricated diaphragm was attached between the positive electrodes, then inserted into a bag. Electrolyte (1.3M LiPF6 dissolved in a mixed solvent of ethylene carbonate (EC) / ethyl methyl carbonate (EMC) / diethyl carbonate (DEC) at a volume ratio of 3 / 5 / 2) was injected into the bag and left to stand for 12 hours. Then, the bag was subjected to a pressure of 10 kgf / cm². 2 Up to 20 kgf / cm 2 The bag was pressed at a temperature of 70°C to 90°C for 5 to 20 seconds, and then disassembled. The diaphragm and positive electrode were removed from the bag, and the diaphragm was separated from the positive electrode plate by approximately 10 mm to approximately 20 mm. The positive electrode and diaphragm were then pulled and peeled off in opposite directions at a 180° angle. The peeling speed was 100 mm / min, and the required force was measured three times in the 20 mm to 40 mm range after the peeling began, and the average value was obtained. The average value was calculated as the average of the measured values.

[0441] The fabricated diaphragm was attached between the negative electrodes, then inserted into a bag. Electrolyte (1.3M LiPF6 dissolved in a 3 / 5 / 2 volume ratio of EC / EMC / DEC) was injected into the bag and left for 12 hours. Then, the bag was subjected to a pressure of 10 kgf / cm². 2 Up to 20 kgf / cm 2 The bag was pressed at a temperature of 70°C to 90°C for 5 to 20 seconds, and then disassembled. The diaphragm and negative electrode were removed from the bag, and the diaphragm was separated from the negative electrode plate by approximately 10 mm to approximately 20 mm. The negative electrode and diaphragm were then pulled and peeled off in opposite directions at a 180° angle. The peeling speed was 100 mm / min, and the required force was measured three times in the 20 mm to 40 mm range after the peeling began, and the average value was obtained. The average value was calculated as the average of the measured values.

[0442] (3) EIS resistance of the diaphragm (unit: Ω) A coin cell for resistance measurement was manufactured using a separator and electrolyte (1.3M LiPF6 dissolved in a mixed solvent of EC / EMC / DEC at a volume ratio of 3 / 5 / 2). After stacking two separator sheets and cutting them into circles with a diameter of 19 mm, the separator was placed on a housing, a gasket was placed on the separator, and 10 drops of electrolyte were applied. A 1 mm thick spacer was placed on the separator. Next, a spring was placed on the result to prevent gaps between the upper and lower ends inside the CR2032 coin cell, and the CR2032 coin cell was covered with a cap and sealed using a special clamp. CR2032 material manufactured by Hohsen Corp. was used when manufacturing the CR2032 coin cell. The resistance of the coin cell was measured using electrochemical impedance spectroscopy (EIS).

[0443] Table 1:

[0444] Thickness: When the heat-resistant layer and the adhesive layer are each formed on each of the two opposing surfaces of the porous substrate, the thickness of only one layer is described.

[0445] As shown in Table 1 above, the example separator for lithium rechargeable batteries can have low resistance and significantly high wet adhesion to each of the positive and negative electrodes.

[0446] Example 5 (1) Preparation of core-shell binder 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0447] Separately, 41.7 g of divinylbenzene, 53.9 g of acrylonitrile, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and the mixture was then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0448] Separately, 29.4 g of PEG (MAL-PEG-SS-CH2CH2-NH2 manufactured by CD Bioparticles) with an adhesive functional group at one end, 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes. This mixture was then added to the first solution, and the reaction was maintained at room temperature for 24 hours to prepare a core-shell binder with the following chemical formula 8. The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0449] Chemical formula 8:

[0450] (x and y are the number of moles in each unit).

[0451] (2) Preparation of linear adhesive I The entire process of synthesizing linear binder I was carried out under a nitrogen atmosphere.

[0452] 40 g of HOOC-PEG-COOH (COOH-CH2O-(PEG)-CH2-COOH) (18.8 mmol) was dissolved in 1 L of dichloromethane (DCM) in a 3 L flask equipped with a stirrer, thermometer, and condenser. Then, 4.64 g of N,N'-dicyclohexylcarbodiimide (DCC, 22.56 mmol) and 2.6 g of N-hydroxysuccinimide (NHS, 22.56 mmol) were added at room temperature, followed by stirring for 12 hours. This solution was then slowly and continuously added to a solution of 28.64 g of cystamine (0.19 mol) dissolved in 200 mL of DCM in a 5 L flask, followed by stirring for 24 hours. The resulting mixture was cooled to 0 °C and filtered to separate the precipitate. The filtrate was evaporated under vacuum, and the remaining residue was dissolved in 400 mL of DMSO and then dialyzed in distilled water to remove impurities. Linear binder I can be obtained by freeze-drying to remove excess moisture. Linear binder I is represented by the following chemical formula 10.

[0453] Linear adhesive I includes the components in chemical formula 8 above. .

[0454] Chemical Formula 10:

[0455] (n is the number of times each unit is repeated).

[0456] (3) Manufacturing of the diaphragm Acrylic binder (10 wt% in distilled water) and boehmite (average particle size D50: 0.2 μm, cubic shape) as filler were mixed at a mass ratio of 1:20 (acrylic binder: filler) based on solid content, added to an aqueous solvent, and milled and dispersed using a bead mill at 25°C for 30 minutes to prepare a dispersion.

[0457] Poly(acrylic acid-co-lithium acrylate-co-acrylamide-co-2-acrylamido-2-methylpropanesulfonate) with a molar ratio of acrylic acid + lithium acrylate, acrylamide and lithium 2-acrylamido-2-methylpropanesulfonate of 10:85:5 was used as an acrylic binder.

[0458] The dispersion was applied to each of the two opposing surfaces of a porous polyethylene fabric (12 μm thick, 120 sec / 100 cc breathability) using a die-coating method to a thickness of 1 μm, and then dried and cured in an oven at 80°C for 16 hours to form a heat-resistant layer.

[0459] The coating solution was prepared by mixing 90 parts by weight of DI water, 9 parts by weight of the prepared core-shell binder, and 1 part by weight of the prepared linear binder I.

[0460] The coating solution is applied to each of the two opposing surfaces of the heat-resistant layer to a thickness of 0.5 μm using a bar coating method, and then stored in an oven at 50°C for 1 hour to form an adhesive layer, thereby manufacturing a separator for lithium rechargeable batteries.

[0461] Example 6 The entire process of synthesizing linear binder II was carried out under a nitrogen atmosphere.

[0462] In a 3L flask equipped with a stirrer, thermometer, and condenser, 40g of mPEG-COOH (H3C-(OCH2CH2)) was added. n -COOH (20 mmol) was dissolved in 1 L of DCM. Then, 5 g of DCC (23.5 mmol) and 2.75 g of NHS (23.5 mmol) were added at room temperature, and the mixture was stirred for 5 hours. Next, this solution was slowly and continuously added to a solution of 47.5 g of cystamine (0.19 mol) dissolved in 1 L of DCM in a 5 L flask, and the mixture was stirred for 24 hours. The resulting mixture was cooled to 0 °C and then filtered to separate the precipitate. The filtrate was evaporated under vacuum, and the remaining residue was dissolved in 400 mL of DMSO and then dialyzed in distilled water to remove impurities. Linear binder II could be obtained by freeze-drying to remove the remaining water. Linear binder II is represented by the following chemical formula 11.

[0463] Chemical Formula 11:

[0464] (n is the number of times each unit is repeated).

[0465] The diaphragm was manufactured in the same manner as in Example 5, except that the prepared linear binder II was used.

[0466] Example 7 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0467] Separately, 41.7 g of divinylbenzene, 45.8 g of acrylonitrile, 12.5 g of lithium acrylate, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0468] Separately, 25.0 g of PEG (MAL-PEG-SS-CH2CH2-NH2 manufactured by CD Bioparticles) with an adhesive functional group at one end, 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes, then added to the first solution. The reaction was then maintained for 24 hours to prepare a core-shell binder having a shell of the following chemical formula 9. The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0469] Chemical formula 9:

[0470] (x, y, z represent the number of moles in each unit).

[0471] Except for using the prepared core-shell binder, the diaphragm is manufactured in the same manner as in Example 5.

[0472] Example 8 Except that the linear binder II prepared in Example 6 is used instead of the linear binder I, the separator for the lithium rechargeable battery is manufactured in the same manner as in Example 7.

[0473] Example 9 The separator for the lithium rechargeable battery is manufactured in the same manner as in Example 5, except that: in Example 5, dimethyl polyethylene glycol (H3CO-PEG-CH3, M... n =2,000)(linear adhesive III) was used as the prepared linear adhesive.

[0474] Comparison Example 6 The separator for the lithium rechargeable battery is manufactured in the same manner as in Example 5, except that in Example 5, PEG without adhesive functional groups at one end is used, a core-shell structured binder comprising a shell without end adhesive functional groups is used, and the linear binder II prepared in Example 6 is used.

[0475] Compare Example 7 The separator for the lithium rechargeable battery is manufactured in the same manner as in Example 5, except that, in Example 5, PEG without adhesive functional groups at one end is used, while a core-shell structure binder comprising a shell without end adhesive functional groups and polyethylene glycol dimethyl ester (H3CO-PEG-CH3, M n =2,000)(Linear adhesive III).

[0476] The physical properties of the diaphragms manufactured according to the example and comparative examples are evaluated in Table 2 below.

[0477] The membrane's air permeability (unit: seconds / 100°C), wet adhesion to the negative electrode and wet adhesion to the positive electrode (unit: gf / mm), and EIS resistance (unit: Ω) were measured in the same manner as described above.

[0478] Table 2:

[0479] Thickness: When the heat-resistant layer and the adhesive layer are each formed on each of the two opposing surfaces of the porous substrate, only the thickness of one layer is described.

[0480] As shown in Table 2 above, the example separator for lithium rechargeable batteries exhibits significantly high wet adhesion and low resistance to each of the positive and negative electrodes. However, as shown in Table 2 above, the separator of the comparative example does not perform well in terms of wet adhesion and resistance to each of the positive and negative electrodes compared to the example.

[0481] Example 10 (1) Preparation of core-shell binder 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0482] Separately, 41.7 g of divinylbenzene, 52.5 g of acrylonitrile, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and the mixture was then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0483] Separately, 30.8 g of PEG (MAL-PEG-SS-CH2CH2-NH2 manufactured by CD Bioparticles) with an adhesive functional group at one end, 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes. This mixture was then added to a first solution, and the reaction was maintained at room temperature for 24 hours to prepare a core-shell binder having the shell of the following chemical formula 8. Through the reaction, 37 parts by weight of PEG with an adhesive functional group at one end and 63 parts by weight of acrylonitrile were polymerized in a total of 100 parts by weight of PEG and acrylonitrile. The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0484] Chemical formula 8:

[0485] (x and y are the number of moles in each unit).

[0486] (2) Preparation of linear adhesive I The entire process of synthesizing linear binder I was carried out under a nitrogen atmosphere.

[0487] In a 3L flask equipped with a stirrer, thermometer, and condenser, 40g of HOOC-PEG-COOH (COOH-CH2O-PEG-CH2-COOH) (18.8mmol) was dissolved in 1L of DCM. Then, 4.64g of DCC (22.56mmol) and 2.6g of NHS (22.56mmol) were added at room temperature, and the mixture was stirred for 12 hours. Next, this solution was slowly and continuously added to a solution of 28.64g of cystamine (0.19mol) dissolved in 200mL of DCM in a 5L flask, and the mixture was stirred for 24 hours. The resulting mixture was cooled to 0°C and filtered to separate the precipitate. The filtrate was evaporated under vacuum, and the remaining residue was dissolved in 400mL of DMSO and then dialyzed in distilled water to remove impurities. Linear binder I can be obtained by freeze-drying to remove the remaining water. Linear binder I is represented by the following chemical formula 10.

[0488] Linear adhesive I includes the components in chemical formula 8 above. .

[0489] Chemical Formula 10:

[0490] (n is the number of times each unit is repeated).

[0491] (3) Manufacturing of the diaphragm An acrylic binder (10 wt% in distilled water) and boehmite (average particle size D50: 200 nm, cubic shape, with hydroxyl groups on its surface) as filler were mixed and added to an aqueous solvent. The mixture was then ground and dispersed using a bead mill at 25°C for 30 minutes to prepare a dispersion.

[0492] Poly(acrylic acid-co-lithium acrylate-co-acrylamide-co-2-acrylamido-2-methylpropanesulfonate) with a molar ratio of acrylic acid + lithium acrylate, acrylamide and lithium 2-acrylamido-2-methylpropanesulfonate of 10:85:5 was used as an acrylic binder.

[0493] The prepared core-shell binder and linear binder I were added to the dispersion, placed in an aqueous solvent, and mixed at 25°C for 30 minutes to prepare a composition for coating.

[0494] In the composition used for coating, an acrylic binder, a core-shell binder, and a linear binder I are included in a weight ratio of 10:0.8:0.2, and the total weight ratio of filler to the acrylic binder, the core-shell binder, and the linear binder is 20:1.

[0495] The composition for coating was applied to each of two opposing surfaces of a porous polyethylene fabric (12 μm thick, 120 sec / 100 cc breathability) using a die-coating method to a thickness of 1 μm, and then dried and cured in an oven at 80°C for 16 hours to form a coating.

[0496] Example 11 The entire process of synthesizing linear binder II was carried out under a nitrogen atmosphere.

[0497] In a 3L flask equipped with a stirrer, thermometer, and condenser, 40g of mPEG-COOH (H3C-(OCH2CH2)) was added. n -COOH (20 mmol) was dissolved in 1 L of DCM. Then, 5 g of DCC (23.5 mmol) and 2.75 g of NHS (23.5 mmol) were added at room temperature, and the mixture was stirred for 5 hours. Next, this solution was slowly and continuously added to a solution of 47.5 g of cystamine (0.19 mol) dissolved in 1 L of DCM in a 5 L flask, and the mixture was stirred for 24 hours. The resulting mixture was cooled to 0 °C and then filtered to separate the precipitate. The filtrate was evaporated under vacuum, and the remaining residue was dissolved in 400 mL of DMSO and then dialyzed in distilled water to remove impurities. Linear binder II could be obtained by freeze-drying to remove the remaining water. Linear binder II is represented by the following chemical formula 11.

[0498] Chemical Formula 11:

[0499] (n is the number of times each unit is repeated).

[0500] Except for using the prepared linear binder II, the diaphragm is manufactured in the same manner as in Example 10.

[0501] Example 12 800 mL of distilled water, 40 g of seed kernels (a copolymer of styrene and acrylate) powder, and 0.8 g of sodium dodecyl sulfate were added to a 3 L flask equipped with a stirrer, thermometer, and condenser. The air inside the flask was then purged with nitrogen. The flask was then heated to 80 °C while stirring to prepare a solution in which the seed kernels were dispersed.

[0502] Separately, 41.7 g of divinylbenzene, 45.8 g of acrylonitrile, 12.5 g of lithium acrylate, 50 g of sodium dodecyl sulfate, and 1,000 mL of distilled water were sequentially added to a 2 L beaker, and then sonicated at room temperature for 10 minutes to prepare a preemulsion. After adding 14 mL of 3 wt% potassium persulfate to the preemulsion solution, the mixture was slowly and continuously added to the seed dispersion over 1.5 hours. The reaction was then maintained for 2 hours for polymerization to prepare the first solution.

[0503] Separately, 25.0 g of PEG (MAL-PEG-SS-CH2CH2-NH2 manufactured by CD Bioparticles) with an adhesive functional group at one end, 7.5 g of potassium persulfate, and 200 mL of distilled water were sequentially added to a 500 mL beaker and mixed at room temperature for 10 minutes, then added to the first solution. The reaction was then maintained for 24 hours to prepare a core-shell binder having a shell of the following chemical formula 9. Through the reaction, 30 parts by weight of PEG with an adhesive functional group at one end, 55 parts by weight of acrylonitrile, and 15 parts by weight of lithium acrylate were polymerized in a total of 100 parts by weight of PEG with an adhesive functional group at one end, acrylonitrile, and lithium acrylate.

[0504] The prepared core-shell binder is a particulate binder with an average particle size D50 of 500 nm.

[0505] Chemical formula 9:

[0506] (x, y, z represent the number of moles in each unit).

[0507] Except for using the prepared core-shell binder, the diaphragm is manufactured in the same manner as in Example 10.

[0508] Example 13 The diaphragm is manufactured in the same manner as in Example 12, except that in Example 12, the linear binder II prepared in Example 11 is used instead of the linear binder I.

[0509] Example 14 The diaphragm is manufactured in the same manner as in Example 10, except that linear binder I is not included in Example 10.

[0510] Compare Example 8 The diaphragm is manufactured in the same manner as in Example 10, except that in Example 10, PEG without end-adhesive functional groups is used, and a core-shell binder comprising a shell without end-adhesive functional groups is used.

[0511] Compare Example 9 The diaphragm is manufactured in the same manner as in Example 10, except that, in Example 10, the core-shell binder is not included.

[0512] The physical properties of the diaphragms manufactured according to the example and comparative examples are evaluated in Table 3 below.

[0513] The membrane's air permeability (unit: seconds / 100°C), wet adhesion to the negative electrode and wet adhesion to the positive electrode (unit: gf / mm), and EIS resistance (unit: Ω) were measured in the same manner as described above.

[0514] Heat shrinkage rate (unit: %) The diaphragms of each example and comparative example were cut into 8cm × 8cm dimensions to prepare samples. After drawing a 5cm × 5cm quadrilateral on the sample surface, the sample was inserted between pieces of paper or alumina powder and placed in an oven at 130°C for 1 hour. It was then removed from the oven to measure the dimensions of the drawn quadrilateral's sides, thereby calculating the thermal shrinkage rates on MD and TD. The thermal shrinkage rate was calculated according to Equation 1 below.

[0515] Equation 1: Thermal shrinkage rate = (L0-L1) / L0×100.

[0516] L0 is the initial length of the diaphragm, and L1 is the length of the diaphragm after being placed at 130°C for 1 hour.

[0517] Table 3:

[0518] As shown in Table 3 above, the example diaphragm provides high wet adhesion to each of the positive and negative electrodes, low thermal shrinkage, low membrane resistance, and improved permeability.

[0519] Although exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and modifications may be made in any form within the scope of the claims, the detailed description of the present disclosure, and the accompanying drawings, and such modifications also fall within the scope of the present disclosure.

Claims

1. A separator for a rechargeable battery, the separator comprising: porous substrate; as well as A coating is formed on at least one surface of the porous substrate. The coating includes a core-shell adhesive having a core and a shell surrounding the core. The shell has an adhesive functional group at its end, and has structural units containing alkylene glycol groups and structural units containing cyano groups.

2. The diaphragm according to claim 1, wherein, The core-shell adhesive includes a water-based adhesive.

3. The diaphragm according to claim 1, wherein, The core-shell binder is a particulate binder with an average particle size D50 of 700 nm or less.

4. The diaphragm according to claim 1, wherein, The adhesive functional groups include one or more combinations of -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2 and -SS- groups.

5. The diaphragm according to claim 4, wherein, The adhesive functional group is represented by chemical formula 6: Chemical Formula 6: ； Among them, R 11 Including substituted or unsubstituted C1-C 10 Alkyl or substituted or unsubstituted C6-C 10 Aryl.

6. The diaphragm according to claim 5, wherein, The adhesive functional groups include -SS-CH2CH2-NH2 or -SS-C6H5-NH2.

7. The diaphragm according to claim 1, wherein, The adhesive functional group is bonded to at least one of the alkylene glycol-containing structural unit and the cyano-containing structural unit via a linker.

8. The diaphragm according to claim 7, wherein, The linker is represented by at least one of chemical formulas 7-1 to 7-12: Chemical formula 7-1: ； Chemical formula 7-2: ； Chemical formula 7-3: ； Chemical formula 7-4: ； Chemical formula 7-5: ； Chemical formula 7-6: ； Chemical formula 7-7: ； Chemical formulas 7-8: ； Chemical formulas 7-9: ； Chemical formula 7-10: ； Chemical formula 7-11: ； Chemical formula 7-12: ； Where n and m are each an integer greater than or equal to 0, and R a R b R c R d and R e Each is independently hydrogen or substituted or unsubstituted C1-C 10 alkyl.

9. The diaphragm according to claim 1, wherein, The structural unit containing an alkylene glycol group is represented by Chemical Formula 1, and the structural unit containing a cyano group is represented by Chemical Formula 2: Chemical Formula 1: ； Where n equals 0 or 1, and R 1 Including linear or branched, substituted or unsubstituted C1-C 10 Alkylene; and Chemical formula 2: ； Among them, R 3 and R 4 Each is independently hydrogen or C1-C3 alkyl, L 1 Includes -C(=O)-, -C(=O)O-, -OC(=O)-, -O-, or -C(=O)NH-, where x is an integer from 0 to 2, L 2 Including substituted or unsubstituted C1-C 10 Alkylene, substituted or unsubstituted C3-C 20 Cycloalkylene, substituted or unsubstituted C6-C 20 aryl or substituted or unsubstituted C3-C 20 It is a subheterocyclic base, and y is an integer from 0 to 2.

10. The diaphragm according to claim 1, wherein, The shell includes: Second copolymer; and Relative to 100 mol% of repeating units of the second copolymer, the amount of the alkylene glycol-containing structural unit is in the range of 15 mol% to 85 mol%, the amount of the cyano-containing structural unit is in the range of 15 mol% to 80 mol%, and the adhesive functional group is bonded to one end of the alkylene glycol-containing structural unit.

11. The diaphragm according to claim 1, wherein, The shell also includes structural units derived from (meth)acrylic acid or (meth)acrylate.

12. The diaphragm according to claim 11, wherein, The structural units derived from (meth)acrylic acid or (meth)acrylate include lithium cations.

13. The diaphragm according to claim 11, wherein, The shell includes: Second copolymer; and Relative to 100 mol% of repeating units of the second copolymer, the amount of the alkylene glycol-containing structural unit is in the range of 15 mol% to 85 mol%, the amount of the cyano-containing structural unit is in the range of 15 mol% to 80 mol%, and the amount of the structural unit derived from (meth)acrylic acid or (meth)acrylate is in the range of greater than 0 mol% and less than or equal to 70 mol%, and the adhesive functional group is bonded to one end of the alkylene glycol-containing structural unit.

14. The diaphragm according to claim 1, wherein, The shell comprises one or more combinations of chemical formulas 8 and 9: Chemical formula 8: ； Where x and y are the number of moles in each unit; and Chemical formula 9: ； Where x, y, and z are the number of moles in each unit.

15. The diaphragm according to claim 1, wherein, The content of the core-shell binder in the coating is in the range of 0.01 wt% to 30 wt%.

16. The diaphragm according to claim 1, wherein, The coating also includes at least one of a heat-resistant adhesive and a filler.

17. The diaphragm according to claim 16, wherein, The heat-resistant adhesive includes a (meth)acrylic adhesive, which comprises structural units containing sulfonic acid groups.

18. The diaphragm according to claim 17, wherein, The (meth)acrylic adhesive further includes at least one of the following structural units: structural units derived from (meth)acrylates or (meth)acrylic acid, cyano-containing structural units, and structural units derived from (meth)acrylamide.

19. The diaphragm according to claim 17, wherein, The coating includes a heat-resistant layer and an adhesive layer. The heat-resistant layer includes the heat-resistant adhesive and the filler. The adhesive layer is located on the heat-resistant layer and includes the core-shell adhesive.

20. The diaphragm according to claim 1, wherein, The coating also includes a linear adhesive.

21. The diaphragm according to claim 20, wherein, The linear adhesive has terminal functional groups.

22. The diaphragm according to claim 21, wherein, The terminal functional groups include adhesive functional groups.

23. The diaphragm according to claim 21, wherein, The adhesive functional groups of the linear adhesive include one or more combinations of -COOH, -OH, -NH2, -C(=O)H, -C(=O)NH2 and -SS- groups.

24. The diaphragm according to claim 21, wherein, The adhesive functional groups of the core-shell adhesive are the same as those of the linear adhesive.

25. The diaphragm according to claim 23, wherein, Functional groups containing the -SS- group are represented by chemical formula 6: Chemical Formula 6: ； Among them, R 11 Is it substituted or unsubstituted C1-C? 10 Alkyl or substituted or unsubstituted C6-C 10 Aryl.

26. The diaphragm according to claim 23, wherein, Functional groups with -SS- bases include -SS-CH2CH2-NH2 and One of -SS-C6H5-NH2.

27. The diaphragm according to claim 20, wherein, The main chain of the linear adhesive has at least one of the following: structural units containing alkylene glycol groups, structural units containing cyano groups, and structural units derived from (meth)acrylic acid or (meth)acrylate.

28. The diaphragm according to claim 20, wherein, The linear adhesive has one or more combinations of chemical formulas 10 and 11: Chemical Formula 10: ;as well as Chemical Formula 11: ； Where n is the number of times each unit is repeated.

29. The diaphragm according to claim 20, wherein, The coating comprises the core-shell binder and the linear binder in a weight ratio ranging from 2:1 to 20:

1.

30. The diaphragm according to claim 20, wherein, The content of the core-shell binder in the coating is in the range of 0.01 wt% to 30 wt%, and the content of the linear binder in the coating is in the range of 0.01 wt% to 25 wt%.

31. A rechargeable battery, said rechargeable battery comprising: Positive electrode; negative electrode; as well as The separator for a rechargeable battery according to any one of claims 1 to 30 is located between the positive electrode and the negative electrode.

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