Battery separator and battery

Abstract

The battery separator and battery of the present invention may include: a base layer; a first inorganic layer disposed on one surface of the base layer and containing first inorganic particles; a second inorganic layer disposed on another surface of the base layer and containing second inorganic particles; and a first electrolyte layer disposed on one surface of the first inorganic layer and containing a first electrolyte composition, wherein the first inorganic particles include flame-retardant inorganic particles, and the second inorganic particles include lithium-ion transport inorganic particles.

Description

Technical Field

[0001] This document claims the benefit of Korean Patent Application No. 10-2024-0189028, filed with the Korean Intellectual Property Office on December 17, 2024, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to battery separators.

[0003] This invention relates to batteries. Background Technology

[0004] Gel polymer electrolytes (GPEs) can contain both a binder and a liquid electrolyte. GPEs are typically contained within the electrodes of a battery and can be bonded to the electrode active materials. In this case, a polyolefin-based membrane can be disposed between the electrodes (positive and negative) to act as a separator to prevent physical short circuits between the electrodes.

[0005] A lithium metal battery is a battery that uses lithium metal as the negative electrode active material. Summary of the Invention

[0006] Technical issues

[0007] The negative electrode of a lithium metal battery may expand during charging and discharging. Uneven deposition of lithium dendrites may occur during charging and discharging. Expanded negative electrode and / or lithium dendrites may cause cracks in the positive electrode. Cracks in the positive electrode may adversely affect battery performance. Excellent battery performance can only be ensured when the expansion of the negative electrode and / or the formation of lithium dendrites is suppressed, or when even if the negative electrode expands or forms lithium dendrites, it does not cause cracks in the positive electrode.

[0008] Technical solution

[0009] One embodiment of the present invention is a battery separator, comprising: a base layer; a first inorganic layer disposed on one surface of the base layer and containing first inorganic particles; a second inorganic layer disposed on another surface of the base layer and containing second inorganic particles; and a first electrolyte layer disposed on one surface of the first inorganic layer and containing a first electrolyte composition, wherein the first inorganic particles include flame-retardant inorganic particles, and the second inorganic particles include lithium-ion transport inorganic particles.

[0010] The first inorganic particles may include SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, Zn2SnO4, ZnSnO3, ZnSn(OH)6, ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or combinations thereof.

[0011] The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle can each be independently in the range of 100 to 1000.

[0012] The true density of the first inorganic particle (g / cm³) 3 The density of the inorganic particles can be less than the true density (g / cm³) of the second inorganic particle. 3 ).

[0013] The second inorganic particle may include Li x Ti y (PO4)3(0 <x<2,0<y<3)、Li x Al y Ti z (PO4)3(0 <x<2,0<y<1,0<z<3)、Li x La y TiO3 (0 <x<2,0<y<3)、Li 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2), or combinations thereof.

[0014] The second inorganic particle may include a garnet-type crystal structure.

[0015] The second inorganic particle may include Li 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

[0016] The base layer may include a polyolefin-based membrane.

[0017] The first electrolyte composition may include a first binder, a first liquid electrolyte, and a first crosslinking agent.

[0018] The first binder may comprise a first unit of vinylidene fluoride and a second unit of a fluorinated alkyl vinyl compound.

[0019] The weight-average molecular weight (g / mol) of the binder can be in the range of 150,000 to 600,000, and the content (wt%) of the second unit of the binder can be in the range of 10 to 25.

[0020] The first liquid electrolyte may contain a non-aqueous solvent, lithium salt, and additives.

[0021] Non-aqueous solvents may include carbonate-based compounds.

[0022] The first electrolyte layer may contain linear carbonate-based compounds with a volume larger than that of cyclic carbonate-based compounds.

[0023] Compounds based on linear carbonates may include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl ethyl carbonate, or combinations thereof.

[0024] Compounds based on linear carbonates can be liquids at room temperature.

[0025] Compounds based on cyclic carbonates may include ethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butyl carbonate, or combinations thereof.

[0026] Compounds based on cyclic carbonates can be solid at room temperature.

[0027] The volume (volume%) of linear carbonate-based compounds in the first electrolyte layer can be in the range of 55 to 95%.

[0028] The first crosslinking agent may include a first-1 crosslinking agent and a first-2 crosslinking agent with different numbers of crosslinkable functional groups, and the number of crosslinkable functional groups of the first-1 crosslinking agent may be greater than the number of crosslinkable functional groups of the first-2 crosslinking agent.

[0029] The number of crosslinkable functional groups in the first-1 crosslinking agent can be 3 or more.

[0030] The first-1 crosslinking agent may include compounds based on tri(meth)acrylate, compounds based on tetra(meth)acrylate, compounds based on penta(meth)acrylate, compounds based on hexa(meth)acrylate, or combinations thereof.

[0031] The first crosslinking agent may include monomeric compounds.

[0032] The first-1 crosslinking agent may include trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, ethoxylated glycerol tri(meth)acrylate, propoxylated glycerol tri(meth)acrylate, tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethyl... Oxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, erythritol tetra(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol penta(meth)acrylate, sorbitol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, or combinations thereof.

[0033] The number of functional groups in the first-2 crosslinking agent can be 2.

[0034] The first-2 crosslinking agent may include compounds based on di(meth)acrylate.

[0035] The first-2 crosslinking agents may include polymer compounds.

[0036] The first-2 crosslinking agents may include polyethylene glycol di(meth)acrylate, poly(ethylene oxide-propylene oxide) di(meth)acrylate, polyurethane di(meth)acrylate, polycarbonate di(meth)acrylate, or combinations thereof.

[0037] The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) in the first electrolyte layer to the weight of the first-2 crosslinking agent (C1-2) in the first electrolyte layer can be in the range of 1:9 to 9:1.

[0038] The battery separator may further include a second electrolyte layer disposed on another surface of the substrate layer and containing a second electrolyte composition.

[0039] Another embodiment of the present invention is a battery, which includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, wherein the separator includes a substrate layer; a first inorganic layer disposed on one surface of the substrate layer and containing first inorganic particles; a second inorganic layer disposed on another surface of the substrate layer and containing second inorganic particles; and a first electrolyte layer disposed on one surface of the first inorganic layer and containing a first electrolyte composition, wherein the first inorganic particles include flame-retardant inorganic particles, and the second inorganic particles include lithium-ion transport inorganic particles.

[0040] The negative electrode may contain lithium metal, and the first electrolyte layer may be disposed adjacent to the positive electrode.

[0041] The separator may further include a second electrolyte layer disposed on another surface of the substrate and containing a second electrolyte composition, the negative electrode may contain lithium metal, the first electrolyte layer may be disposed adjacent to the positive electrode, and the second electrolyte layer may be disposed adjacent to the negative electrode.

[0042] Beneficial effects

[0043] The battery separator of the present invention can have charge carrier (e.g., lithium ion) transfer characteristics on one surface and high elasticity on another surface.

[0044] The battery of the present invention can protect the positive electrode and at the same time exhibit excellent electrical performance. Detailed Implementation

[0045] This document may use ordinal numbers such as "first" and "second" to refer to multiple components. There is no order of precedence among the components.

[0046] In this document, when a specific commercial product is used as a component, the characteristics of the component may refer to the characteristics stated in the product's Technical Data Sheet (TDS) or Certificate of Analysis (COA).

[0047] In this document, when the physical properties of a particular material vary with temperature and pressure, the measurement standard for those physical properties may be at room temperature (25°C) and atmospheric pressure (101.325 kPa). This conforms to SATP (Standard Ambient Temperature and Pressure) as defined in the CRC Handbook of Chemistry and Physics.

[0048] In this document, the numerical range "within the range of A to B" means "A or greater and B or less".

[0049] The values ​​mentioned in this document are rounded. For example, 1.5 is a number in the range of 1.45 to 1.54.

[0050] The invention is described in more detail below.

[0051] One embodiment of the present invention is a battery separator.

[0052] In this document, a battery may include any device that performs an electrochemical reaction.

[0053] A battery can refer to any type of primary battery, secondary battery, fuel cell, solar cell, or capacitor. A battery can refer to a lithium secondary battery. Lithium secondary batteries can include lithium metal secondary batteries, lithium polymer secondary batteries, lithium-ion polymer secondary batteries, or lithium-ion secondary batteries.

[0054] A battery separator can be disposed between the electrodes in a battery. Specifically, a battery separator can be disposed between the positive and negative electrodes in a battery. The battery separator prevents physical contact (short circuit) between the positive and negative electrodes in the battery. Charge carriers (e.g., lithium ions) can move between the electrodes through the battery separator.

[0055] The battery separator of the present invention includes a substrate layer; an inorganic layer; and a first electrolyte layer. The separator may further include a second electrolyte layer. The second electrolyte layer will be described later.

[0056] The substrate layer allows fluid to move from one surface of the substrate layer to another.

[0057] The inorganic layer contains inorganic particles. These inorganic particles can impart predetermined properties to the battery separator. For example, they can impart lithium-ion transport properties and / or thermal properties (heat resistance, flame retardancy, etc.) to the battery separator.

[0058] The first electrolyte layer can provide a path for charge carriers to move through the battery separator.

[0059] The inorganic layer comprises a plurality of inorganic layers containing different inorganic particles. The inorganic layer includes a first inorganic layer and a second inorganic layer. The first inorganic layer contains first inorganic particles. The second inorganic layer contains second inorganic particles. The first inorganic particles and the second inorganic particles exhibit different properties.

[0060] A first inorganic layer is disposed on one surface of the substrate layer. A second inorganic layer is disposed on another surface of the substrate layer facing the first surface. Specifically, the first inorganic layer may be disposed on the first surface of the substrate layer, and the second inorganic layer may be disposed on the second surface of the substrate layer facing the first surface. The thicknesses of the first and second inorganic layers may be the same or different from each other.

[0061] The first electrolyte layer is disposed on one surface of the first inorganic layer. That is, the first electrolyte layer is disposed on one surface of the substrate layer, and the first inorganic layer is disposed between the substrate layer and the first electrolyte layer.

[0062] The electrolyte layer contains an electrolyte composition. The composition contained in the first electrolyte layer is a first electrolyte composition. The composition contained in the second electrolyte layer is a second electrolyte composition. The electrolyte composition may be a gel polymer electrolyte composition.

[0063] In this document, the gel polymer electrolyte is a gel-phase electrolyte and comprises a polymer matrix and a liquid electrolyte impregnated therein. Here, the polymer matrix can physically support the gel polymer electrolyte. The liquid electrolyte can impart ionic conductivity to the gel polymer electrolyte.

[0064] In this document, an electrolyte composition refers to a composition that can become an electrolyte by itself or by a predetermined reaction.

[0065] The first category of inorganic particles includes flame-retardant inorganic particles.

[0066] Flame-retardant inorganic particles can add flame-retardant properties to battery separators and prevent the battery's internal temperature from rising sharply.

[0067] The second type of inorganic particles includes lithium-ion transport inorganic particles.

[0068] Lithium-ion transport inorganic particles may contain lithium but exhibit the function of facilitating lithium-ion movement without storing lithium. A defect may exist within these particles. Charge carriers, such as lithium ions, can utilize this defect to move. Therefore, lithium-ion transport inorganic particles can improve lithium-ion conductivity in batteries, thereby improving battery performance.

[0069] The battery separator of the present invention can reduce the volume expansion of the electrode by setting flame-retardant inorganic particles adjacent to the electrolyte layer, and reduce the side reactions with the electrode by setting lithium-ion transport inorganic particles on the opposite side.

[0070] Unbound by theory, it is believed that the arrangement of inorganic particles can reduce damage caused by the volume expansion of adjacent electrodes. In addition, lithium-ion transport inorganic particles can reduce side reactions with the electrodes, so that setting non-lithium-ion transport inorganic particles on one side and lithium-ion transport inorganic particles on the opposite side can effectively reduce battery degradation caused by electrode volume expansion and side reactions.

[0071] Therefore, the battery separator of the present invention, in which two inorganic layers with opposite properties are arranged facing each other across a substrate, is particularly suitable for batteries in which the positive and negative electrodes require opposite properties.

[0072] For example, the negative electrode of a lithium metal battery containing lithium metal as the negative electrode may expand during charging and discharging, thereby causing cracks in the positive electrode. Here, the first inorganic layer of the battery separator of the present invention can be disposed on the positive electrode side, and the second inorganic layer can be disposed on the negative electrode side. The formation of lithium dendrites can be suppressed by the second inorganic layer, and even if they do form, cracks in the positive electrode can be reduced by the first inorganic layer.

[0073] Unbound by theory, it is believed that the arrangement of inorganic particles can reduce damage caused by the volume expansion of the negative electrode. In addition, lithium-ion transport inorganic particles can reduce side reactions with the negative electrode. Thus, placing non-lithium-ion transport inorganic particles on the surface facing the positive electrode and lithium-ion transport inorganic particles on the surface facing the negative electrode can prevent damage to the positive electrode caused by the volume expansion of the negative electrode and effectively reduce battery degradation caused by side reactions with the negative electrode.

[0074] The battery separator is described in more detail below.

[0075] The first inorganic particles may include SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, Zn2SnO4, ZnSnO3, ZnSn(OH)6, ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or combinations thereof. Preferably, the first inorganic particles may include ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or combinations thereof. More preferably, the first inorganic particles may include Al2O3, AlOOH, Al(OH)3, TiO2, or combinations thereof.

[0076] The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle can each be independently in the range of 100 to 1000.

[0077] Specifically, the D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle can each independently be 150 or greater, 200 or greater, 250 or greater, 300 or greater, 350 or greater, 400 or greater, 450 or greater, or 500 or greater. The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle can each independently be 950 or less, 900 or less, 850 or less, 800 or less, 750 or less, 700 or less, 650 or less, 600 or less, 550 or less, or 500 or less.

[0078] The true density of the first inorganic particle can be less than that of the second inorganic particle. Inorganic particles can improve the mechanical and thermal properties of the battery separator by imparting rigidity and heat resistance. When the battery separator contains multiple types of inorganic particles with different densities, heavier particles can form a framework at the bottom, while lighter particles can fill the upper part or the gaps formed by the heavier particles. During this process, a uniform pore structure can be formed inside the battery separator. This uniform pore structure can enhance the electrolyte solution impregnation and ionic conductivity of the battery separator.

[0079] In this document, a uniform pore structure can refer to a structure in which the average size, shape, density, etc., of the pores are almost constant regardless of the position of the layers, so that the path of material movement within them can remain constant. A uniform pore structure can also refer to a state in which the size and spatial distribution of the pores vary little throughout the entire battery separator including the pores, the pores are continuously connected to each other, and the pores are not located in a specific direction or position.

[0080] In this document, the true density of particles can refer to the density calculated solely based on the particle's own mass and volume, excluding internal voids. The true density of inorganic particles can be a known value for the corresponding inorganic particle or a value measured using known methods. The true density of inorganic particles can be determined based on the chemical composition of the corresponding inorganic particle.

[0081] The true density of the first inorganic particle (g / cm³) 3 The value can be in the range of 1.5 to 6. Specifically, the true density (g / cm³) of the first inorganic particle... 3 The density can be 2.0 or greater, 2.5 or greater, 3.0 or greater, 3.5 or greater, or 3.95 or greater. The true density (g / cm³) of the first inorganic particle. 3 () can be 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.95 or less, or 3.5 or less.

[0082] The true density of the second inorganic particle (g / cm³) 3 The true density (g / cm³) of the second inorganic particle can range from 2.5 to 10. 3 The true density (g / cm³) of the second inorganic particle can be 3.0 or greater, 3.5 or greater, 4.0 or greater, 4.5 or greater, 5.0 or greater, 5.4 or greater, 5.5 or greater, 6.0 or greater, or 6.5 or greater. 3 () can be 9.5 or less, 9.0 or less, 8.5 or less, 8.0 or less, 7.5 or less, 7.0 or less, 6.5 or less, or 6.0 or less.

[0083] The second inorganic particle may include Li x Ti y (PO4)3(0 <x<2,0<y<3)、Li x Al y Ti z (PO4)3(0 <x<2,0<y<1,0<z<3)、Li x La y TiO3 (0 <x<2,0<y<3)、Li 6+x La3Zr 2-y M y O12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2), or combinations thereof. Preferably, the second inorganic particle may include Li. 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

[0084] The second inorganic particle may include a garnet-type crystal structure.

[0085] Garnet-type crystal structures can have a cubic structure. Garnet-type crystal structures can have an A3B5O structure. 12 The structure can be either in the form of A3B2(SiO4)3. A can include divalent, trivalent, or tetravalent ions of La, Ca, or Y. B can include tetravalent ions of Zr or Al. Thus, a stable garnet-type crystal structure can be formed.

[0086] Li 6+x La3Zr 2-y M y O 12-z Compounds with the following crystal structures (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2) are considered LLZO-based and are representative of compounds with a garnet-type crystal structure. Besides LLZO-based compounds, garnet-type crystal structures can also include Li5La3Nb2O. 12 Li6CaLa2Nb2O 12 Li5La3Ta2O 12 Li5La3M2O 12 (M=Nb, Ta, Sb, etc.) etc.

[0087] Garnet-type crystal structures can be advantageous in providing pathways for lithium-ion movement, exhibiting high ionic conductivity, excellent high-temperature thermal stability, and low chemical reactivity. By equipping the second inorganic particles with a garnet-type crystal structure, the capacity characteristics and stability of batteries incorporating these particles can be improved.

[0088] The first inorganic layer may contain only first inorganic particles as inorganic particles. Furthermore, the second inorganic layer may contain only second inorganic particles as inorganic particles. That is, the inorganic particles in both the first and second inorganic layers may consist of first and second inorganic particles. For example, the first and second inorganic layers may each independently not contain a combination of first and second inorganic particles.

[0089] The substrate layer may include a polyolefin-based membrane. Specifically, the substrate layer may include a polyolefin-based porous membrane.

[0090] Here, a polyolefin-based porous membrane refers to a porous membrane that contains a polyolefin-based resin as its main component.

[0091] Polyolefin-based porous membranes may contain polyolefin-based resin in an amount of 50% or more, 90% or more, or 95% or more of the total material constituting the polyolefin-based porous membrane.

[0092] The weight-average molecular weight of the components contained in polyolefin-based resins can be 3 × 10⁻⁶. 5 Up to 15×10 6 When the weight-average molecular weight of the components contained in a polyolefin-based resin is 1,000,000 or greater, the strength of the separator, including a polyolefin-based porous membrane, can be improved.

[0093] Polyolefin-based resins may include thermoplastic resins. Thermoplastic resins may include homopolymers (e.g., polyethylene, polypropylene, polybutene) or copolymers (e.g., ethylene-propylene copolymers) formed by the polymerization of monomers (e.g., ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene).

[0094] Polyolefin-based porous membranes can be layers containing only one of these polyolefin-based resins, or layers containing two or more of these polyolefin-based resins. Polyethylene and high-molecular-weight polyethylene, with ethylene as the main backbone, can block the flow of overcurrent (shutdown) at lower temperatures. Furthermore, polyolefin-based porous membranes can further contain components other than the polyolefin-based resin that do not impair the membrane's function.

[0095] The first electrolyte composition may include a first binder, a first liquid electrolyte, and a first crosslinking agent.

[0096] The first binder may form a polymer matrix alone or together with the first crosslinking agent.

[0097] The first liquid electrolyte can be impregnated in a polymer matrix formed by the first binder. The first liquid electrolyte can impart ionic conductivity to the gel polymer electrolyte.

[0098] As a crosslinking agent, the first crosslinking agent can form a polymer matrix in the gel polymer electrolyte, either alone or together with the first binder. The first crosslinking agent can bind the first binder and / or the first crosslinking agent within the polymer matrix.

[0099] The first binder can form a framework in the first electrolyte layer formed from the first electrolyte composition. The first binder can have suitable crystallinity and polarity to enhance the ionic conductivity of the battery separator. Specifically, the polar portion of the first binder can be bonded to a first crosslinking agent. In this case, the first binder can form a crosslinked structure in the first electrolyte layer.

[0100] The first adhesive may include a fluorine-based adhesive. A fluorine-based adhesive may refer to an adhesive whose constituent units contain fluorine in whole or in part. A fluorine-based adhesive may include a PVDF-based adhesive.

[0101] PVDF-based adhesives can be homopolymers or copolymers comprising polymeric units derived from vinylidene fluoride. Fluorine-based adhesives can comprise a first unit of vinylidene fluoride and a second unit of a fluorinated alkyl vinyl compound. PVDF-based adhesives can be block copolymers or random copolymers comprising the first and second units. Preferably, PVDF-based adhesives can be random copolymers comprising the first and second units.

[0102] Fluorinated alkyl vinyl compounds can refer to those in which C n H (2n+1-y) F y The compound represented by at least one fluorinated alkyl group bonded to a vinyl group. However, vinylidene fluoride is excluded.

[0103] Fluorinated alkyl vinyl compounds may include at least one selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene. Preferably, the fluorinated alkyl vinyl compound may include at least one selected from hexafluoropropylene, tetrafluoroethylene, and chlorotrifluoroethylene. More preferably, the fluorinated alkyl vinyl compound may include hexafluoropropylene.

[0104] The content of the second unit in fluorine-based binders can be adjusted. The content of the second unit in fluorine-based binders can affect the crystallinity of fluorine-based binders, the ionic conductivity of battery separators, and mechanical strength.

[0105] The content (by weight%) of the second unit in the fluorine-based adhesive can be in the range of 10 to 25%. Preferably, the content (by weight%) of the second unit in the fluorine-based adhesive can be 15 or more, 16 or more, 17 or more, or 18 or more. The content (by weight%) of the second unit in the fluorine-based adhesive can be 23 or less, 21 or less, 20 or less, or 19 or less.

[0106] The content of the first and second units in the fluorine-based binder can be determined by the fluorine-based binder. 19 F-NMR analysis was used for measurement.

[0107] The weight-average molecular weight (g / mol) of the fluorine-based adhesive can also be adjusted. The weight-average molecular weight (g / mol) of the fluorine-based adhesive can be in the range of 150,000 to 600,000. Preferably, the weight-average molecular weight (g / mol) of the fluorine-based adhesive can be 200,000 or greater, 250,000 or greater, 300,000 or greater, or 350,000 or greater. The weight-average molecular weight (g / mol) of the fluorine-based adhesive can be 550,000 or less, 500,000 or less, 450,000 or less, 400,000 or less, or 350,000 or less.

[0108] The weight-average molecular weight of fluorine-based binders can be measured by gel permeation chromatography.

[0109] The melting point of the fluorine-based adhesive can also be adjusted. The melting point (°C) of the fluorine-based adhesive can be in the range of 100 to 140. Preferably, the melting point (°C) of the fluorine-based adhesive can be 110 or higher, or 115 or higher. The melting point (°C) of the fluorine-based adhesive can be 135 or lower, 130 or lower, or 125 or lower.

[0110] The first liquid electrolyte may be impregnated in a first binder, specifically in a polymer matrix formed by the first binder. The first liquid electrolyte may further comprise a non-aqueous solvent, a lithium salt, and additives.

[0111] Non-aqueous solvents can refer to organic solvents that do not contain water or, if they do contain water, contain only trace amounts of water. Non-aqueous solvents can include carbonate-based compounds, ether-based compounds, ester-based compounds, compounds containing polar functional groups, or mixtures thereof. Preferably, non-aqueous solvents can include carbonate-based compounds.

[0112] Ether-based compounds may include dimethoxyethane, diethoxyethane, tetrahydrofuran, or combinations thereof.

[0113] Ester-based compounds may include N-methyl-2-pyrrolidone (NMP), γ-butyrolactone, or combinations thereof.

[0114] Compounds containing polar functional groups may include dimethyl sulfoxide, acetonitrile, or combinations thereof.

[0115] Carbonate-based compounds may include linear carbonate-based compounds, cyclic carbonate-based compounds, or combinations thereof. Preferably, carbonate-based compounds may include both linear carbonate-based compounds and cyclic carbonate-based compounds.

[0116] The first electrolyte layer may contain a linear carbonate-based compound with a volume larger than that of a cyclic carbonate-based compound. In this case, the miscibility of the binder with the liquid electrolyte increases, and abnormal viscosity increases in the first electrolyte composition can be prevented.

[0117] The volume of carbonate-based compounds in the electrolyte layer can be adjusted by the volume of carbonate-based compounds in the electrolyte composition.

[0118] In this document, linear carbonate-based compounds refer to open-chain diesters of carbonic acid. Specifically, linear carbonate-based compounds include structures in which the two hydroxyl groups of carbonic acid are esterified with different alcohols and the entire molecule does not form a ring.

[0119] In this document, compounds based on cyclic carbonates refer to lactones whose ring structure includes a -O-CO-O- skeleton of a carbonate group. Specifically, compounds based on cyclic carbonates include structures in which two hydroxyl groups in a molecule form ester bonds with the same carbonate group at both ends, and the ring includes an -O-CO-O- skeleton.

[0120] Compounds based on linear carbonates may include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl ethyl carbonate, or combinations thereof.

[0121] Specifically, linear carbonate-based compounds may include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, or combinations thereof.

[0122] More specifically, linear carbonate-based compounds may include ethyl methyl carbonate.

[0123] Compounds based on linear carbonates can be liquids at room temperature.

[0124] Compounds based on cyclic carbonates may include ethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butyl carbonate, or combinations thereof.

[0125] Specifically, compounds based on cyclic carbonates may include ethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, propylene carbonate, butyl carbonate, or combinations thereof.

[0126] More specifically, compounds based on cyclic carbonates may include ethylene carbonate, vinylene carbonate, ethylene carbonate, propylene carbonate, or combinations thereof.

[0127] From the perspective of the miscibility of the first binder with the first liquid electrolyte, the viscosity adjustment of the first electrolyte composition, and the safety of the battery, it may be preferable to combine linear carbonate-based compounds and cyclic carbonate-based compounds in different phases.

[0128] Compounds based on cyclic carbonates can be solid at room temperature. Specifically, compounds based on cyclic carbonates may include ethylene carbonate.

[0129] The amounts of linear carbonate-based compounds and cyclic carbonate-based compounds used can also be appropriately adjusted within the range that the above conditions are met.

[0130] The volume (volume%) of linear carbonate-based compounds in the first electrolyte layer can be in the range of 55 to 95%.

[0131] Preferably, the volume (volume %) of the linear carbonate-based compound in the first electrolyte layer can be 60 or greater, 65 or greater, or 70 or greater. The volume (volume %) of the linear carbonate-based compound in the first electrolyte layer can be 90 or less, 85 or less, 80 or less, or 75 or less.

[0132] The volume (volume %) of the cyclic carbonate-based compound in the first electrolyte layer can be in the range of 5 to 45. Preferably, the volume (volume %) of the cyclic carbonate-based compound in the first electrolyte layer can be 10 or greater, 15 or greater, 20 or greater, or 25 or greater. The volume (volume %) of the cyclic carbonate-based compound in the first electrolyte layer can be 40 or less, 35 or less, or 30 or less.

[0133] Lithium salts are soluble in non-aqueous solvents. Lithium salts can refer to materials that dissociate into lithium cations and anions upon dissociation.

[0134] Lithium salts may include LiPF6, LiBF4, LiCl, LiBr, LiI, LiClO4, LiAsF6, LiCH3CO2, LiCF3SO3, LiN(CF3SO2)2, LiN(FSO2)2, LiC(CF2SO2)3, or combinations thereof. Preferably, the lithium salt may include LiN(CF3SO2)2.

[0135] Additives can refer to substances that are applied in small amounts to liquid electrolytes to stabilize the electrode interface, improve electrochemical stability, regulate conduction characteristics, improve temperature characteristics, and inhibit gas generation.

[0136] The additive may include vinylene carbonate, 1,3-propanesulfonyl lactone, 1,3-propenesulfonyl lactone, lithium difluorophosphate, lithium tetrafluoro(oxalate)phosphate, lithium bis(fluorosulfonyl)imide, fluoroethylene carbonate, ethylene ethylene carbonate, or combinations thereof. Preferably, the additive may include vinylene carbonate.

[0137] Since the first liquid electrolyte is impregnated in the first binder or a polymer matrix formed by the first binder in the first electrolyte layer, the thickness of the first electrolyte layer can typically be thick. Specifically, the first electrolyte layer can be thicker than the base layer.

[0138] The first crosslinking agent comprises a plurality of crosslinking agent types. Specifically, the first crosslinking agent may comprise a first-1 crosslinking agent and a first-2 crosslinking agent with different numbers of crosslinkable functional groups. The number of crosslinkable functional groups in the first-1 crosslinking agent may be greater than the number of crosslinkable functional groups in the first-2 crosslinking agent. Here, the number of crosslinkable functional groups in the crosslinking agent may refer to the number of crosslinkable functional groups per molecule of the crosslinking agent. The crosslinkable functional groups may be functional groups used for connecting binders and / or crosslinking agents in a polymer matrix.

[0139] When the first electrolyte composition contains a plurality of crosslinking agents with different numbers of crosslinkable functional groups, the first electrolyte layer can be prepared at a rapid crosslinking rate and can exhibit high crosslinking density and appropriate flexibility.

[0140] Unbound by theory, it is believed that the superior properties of the electrolyte layer (such as crosslinking rate, crosslinking density, and flexibility) are due to the fact that the first-1 crosslinking agent can form a dense crosslinked structure, and the first-2 crosslinking agent can provide space within which liquid electrolytes can be impregnated.

[0141] The first crosslinking agent can have 3 or more crosslinkable functional groups. In this case, the first crosslinking agent can form a dense crosslinked structure. Specifically, the first crosslinking agent can have 6 or fewer, 5 or fewer, or 4 or fewer crosslinkable functional groups.

[0142] The crosslinkable functional group may include a photoreactive functional group. Specifically, the crosslinkable functional group may include a (meth)acryloyl group as a photoreactive functional group. The first-1 crosslinking agent and the first-2 crosslinking agent may include compounds based on polyfunctional (meth)acrylates. Preferably, from the perspective of the rate of crosslinking reaction and preventing the electrochemical properties from deteriorating due to the rigidity of the polymer network, the crosslinkable functional group may include an acryloyl group as a photoreactive functional group.

[0143] Therefore, the first-1 crosslinking agent may include compounds based on tri(meth)acrylate, compounds based on tetra(meth)acrylate, compounds based on penta(meth)acrylate, compounds based on hexa(meth)acrylate, or combinations thereof.

[0144] Specifically, the first-1 crosslinking agent may include a triacrylate-based compound, a tetraacrylate-based compound, a pentaacrylate-based compound, a hexaacrylate-based compound, or a combination thereof.

[0145] More specifically, the first-1 crosslinking agent may include a triacrylate-based compound, a tetraacrylate-based compound, or a combination thereof.

[0146] More specifically, the first-1 crosslinking agent may include triacrylate-based compounds.

[0147] The first-1 crosslinking agent may include monomeric compounds. A monomeric crosslinking agent may refer to a component other than the crosslinkable functional group that is derived from a monomer.

[0148] The first-1 crosslinking agent may include trimethylolpropane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, ethoxylated glycerol tri(meth)acrylate, propoxylated glycerol tri(meth)acrylate, tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethyl... Oxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, erythritol tetra(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol penta(meth)acrylate, sorbitol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, or combinations thereof.

[0149] Specifically, the first-1 crosslinking agent may include trimethylolpropane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, erythritol tetraacrylate, bis(trimethylolpropane) tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated dipentaerythritol pentaacrylate, sorbitol pentaacrylate, dipentaerythritol hexaacrylate, ethoxylated dipentaerythritol hexaacrylate, sorbitol hexaacrylate, or combinations thereof.

[0150] More specifically, the first-1 crosslinking agent may include trimethylolpropane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, erythritol tetraacrylate, bis(trimethylolpropane tetraacrylate), or combinations thereof.

[0151] More specifically, the first-1 crosslinking agent may include trimethylolpropane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, or combinations thereof.

[0152] The number of crosslinkable functional groups in the first-2 crosslinking agent can be less than the number of crosslinkable functional groups in the first-1 crosslinking agent. If the number of crosslinkable functional groups in the first-1 crosslinking agent is 3, then the number of crosslinkable functional groups in the first-2 crosslinking agent can be 2. If the number of crosslinkable functional groups in the first-1 crosslinking agent is 4, then the number of crosslinkable functional groups in the first-2 crosslinking agent can be 2 or 3. If the number of crosslinkable functional groups in the first-1 crosslinking agent is 5, then the number of crosslinkable functional groups in the first-2 crosslinking agent can be 2, 3, or 4. If the number of crosslinkable functional groups in the first-1 crosslinking agent is 6, then the number of crosslinkable functional groups in the first-2 crosslinking agent can be 2, 3, 4, or 5.

[0153] Specifically, regardless of the number of crosslinkable functional groups in the first-1 crosslinking agent, the number of crosslinkable functional groups in the first-2 crosslinking agent can be 2. When the number of crosslinkable functional groups in the first-2 crosslinking agent is as small as possible, the first-2 crosslinking agent can provide space in which liquid electrolytes can be impregnated.

[0154] Since the crosslinking agent can contain a photoreactive functional group (specifically (meth)acryloyl) and the number of functional groups in the first-2 crosslinking agent can be 2, the first-2 crosslinking agent can include a compound based on di(meth)acrylate.

[0155] Furthermore, since the photoreactive functional group preferably includes an acryloyl group, the first-2 crosslinking agent may include a diacrylate-based compound.

[0156] The first-2 crosslinking agents may include polymer compounds. A polymer crosslinking agent can mean that the remainder, excluding the crosslinkable functional groups, is derived from a polymer.

[0157] Preferably, the first-1 crosslinking agent may comprise a monomeric compound, and the first-2 crosslinking agent may comprise a polymeric compound. That is, when the crosslinking agent with a larger number of functional groups is a monomer and the crosslinking agent with a smaller number of functional groups is a polymer, the superior properties of the electrolyte layer, such as crosslinking rate, crosslinking density, and flexibility, can be more appropriately exhibited.

[0158] The first-2 crosslinking agents may include polyethylene glycol di(meth)acrylate, poly(ethylene oxide-propylene oxide) di(meth)acrylate, polyurethane di(meth)acrylate, polycarbonate di(meth)acrylate, or combinations thereof.

[0159] Specifically, the first-2 crosslinking agent may include polyethylene glycol diacrylate, poly(ethylene oxide-propylene oxide) diacrylate, polyurethane diacrylate, polycarbonate diacrylate, or a combination thereof.

[0160] More specifically, the first-2 crosslinking agent may include polyethylene glycol diacrylate, polyurethane diacrylate, or a combination thereof.

[0161] More specifically, the first-2 crosslinking agent may include polyurethane diacrylate.

[0162] When the first-second crosslinking agent comprises a polymer compound, the molecular weight of the polymer compound can also be adjusted. The first-second crosslinking agent may include polyethylene glycol diacrylate with a molecular weight in the range of 400 g / mol to 700 g / mol, polyurethane diacrylate with a molecular weight in the range of 1400 g / mol to 2100 g / mol, or a combination thereof. Specifically, the first-second crosslinking agent may include polyurethane diacrylate with a molecular weight in the range of 1400 g / mol to 2100 g / mol.

[0163] The mixing ratio of the first-1 crosslinking agent and the first-2 crosslinking agent can also be adjusted appropriately.

[0164] The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) in the first electrolyte layer to the weight of the first-2 crosslinking agent (C1-2) in the first electrolyte layer can be in the range of 1:9 to 9:1.

[0165] Preferably, the ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) to the weight of the first-2 crosslinking agent (C1-2) in the first electrolyte layer can be 1.5:8.5 or greater, 2:8 or greater, 2.5:7:5 or greater, 3:7 or greater, 3.5:6.5 or greater, 4:6 or greater, or 4.5:5.5 or greater. The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) to the weight of the first-2 crosslinking agent (C1-2) in the first electrolyte layer can be 8.5:1.5 or less, 8:2 or less, 7.5:2.5 or less, 7:3 or less, 6.5:3.5 or less, 6:4 or less, or 5.5:4.5 or less.

[0166] On the other hand, the first electrolyte layer may contain a first-1 crosslinking agent with a weight greater than that of the first-2 crosslinking agents. The molecular weight of a crosslinking agent with a smaller number of crosslinkable functional groups is higher than that of a crosslinking agent with a larger number of crosslinkable functional groups. For this reason, the number of crosslinks per unit volume or unit mass of a crosslinking agent with a smaller number of crosslinkable functional groups is lower than that of a crosslinking agent with a larger number of crosslinkable functional groups. Therefore, a crosslinking agent with a smaller number of crosslinkable functional groups may be detrimental to a smooth crosslinking process. Therefore, it may be more advantageous for the first electrolyte layer to contain a first-1 crosslinking agent with a weight greater than that of the first-2 crosslinking agents. Furthermore, in this case, the elasticity of the battery (specifically the electrolyte layer (more specifically the first electrolyte layer)) can be increased.

[0167] The weights of the first-1 crosslinking agent and the first-2 crosslinking agent in the first electrolyte layer can be adjusted by the weights of the first-1 crosslinking agent and the first-2 crosslinking agent in the first electrolyte composition.

[0168] The first electrolyte layer may further comprise an initiator. Specifically, the first electrolyte composition may further comprise a first initiator.

[0169] When a predetermined stimulus is applied, the first initiator can initiate a reaction in which the first binder forms a polymer matrix.

[0170] The first initiator may include a thermal polymerization initiator, a photopolymerization initiator, or a combination thereof. Preferably, the initiator may include a photopolymerization initiator.

[0171] Photopolymerization initiators may include short-wavelength photopolymerization initiators, long-wavelength photopolymerization initiators, or combinations thereof. Preferably, the photopolymerization initiator may include a long-wavelength photopolymerization initiator.

[0172] Short-wavelength photopolymerization initiators may include IRGACURE 127 (1,1'-(methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone]), IRGACURE 1173 (2-hydroxy-2-methylphenylacetone, HMPP), DMPA (2,2-dimethoxy-2-phenylacetophenone), HOMPP (2-hydroxy-2-methylphenylacetone), LAP (phenyl-2,4,6-trimethylbenzoylphosphine), or combinations thereof.

[0173] Long-wavelength photopolymerization initiators may include at least one selected from bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and ethyl (2,4,6-trimethylbenzoyl)phenylphosphine oxide. Preferably, the long-wavelength photopolymerization initiator may include ethyl (2,4,6-trimethylbenzoyl)phenylphosphine oxide (TPO-L).

[0174] Furthermore, the first electrolyte composition can be impregnated in the pores of the substrate layer. Therefore, at least a portion of the first electrolyte layer comprising the cured product of the first electrolyte composition can be impregnated in the pores of the substrate layer.

[0175] An electrolyte layer can be formed by curing an electrolyte composition. The electrolyte layer may contain a cured product of the electrolyte composition. Specifically, a first electrolyte layer may contain a cured product of a first electrolyte composition.

[0176] The curing method may include, for example, thermal curing, photocuring, and thermo-photocuring. Preferably, the curing method is photocuring.

[0177] The cured product of a composition can refer to a product that undergoes a chemical process in which the composition hardens or cures when the structure of the components contained in the composition changes due to chemical reactions between the components. Curing can be different from drying, which is a physical process in which a portion of the composition dries or hardens when some of the components contained in the composition (e.g., solvents such as water, volatile components) evaporate.

[0178] UV curing can be used as a method to form the first electrolyte layer on the substrate. UV curing is a method of forming cross-linked structures between binders, between binders and crosslinking agents, or between crosslinking agents using external force. According to the UV curing method, the process of binder forming the polymer matrix, the dispersion process of the binder and inorganic particles, and the impregnation process of the liquid electrolyte can be carried out in the same step.

[0179] The UV curing method may include the following steps. The numbering of the steps does not refer to their order:

[0180] (1) Preparation of electrolyte composition;

[0181] (2) Applying the electrolyte composition to one or both surfaces of the substrate layer; and

[0182] (3) Irradiate the electrolyte composition with UV light.

[0183] In step (1), the preparation of the electrolyte composition may include the direct preparation of the electrolyte composition or the application of a pre-prepared electrolyte composition.

[0184] There are no particular restrictions on the application method and thickness of the electrolyte composition.

[0185] There are no particular restrictions on the conditions under which the electrolyte composition is irradiated with UV light.

[0186] In addition to the first electrolyte layer, the battery separator of the present invention may further include another electrolyte layer. Specifically, the battery separator may further include a second electrolyte layer.

[0187] The second electrolyte layer can be disposed on the opposite side of the first electrolyte layer. Specifically, the second electrolyte layer can be disposed on another surface of the substrate layer. The other surface of the substrate layer can face one surface of the substrate layer.

[0188] The second electrolyte layer may contain an electrolyte composition. The electrolyte composition contained in the second electrolyte layer may be a second electrolyte composition.

[0189] The second electrolyte composition may have the same or different composition and / or properties as the first electrolyte composition. Therefore, the descriptions of the first electrolyte composition and the first electrolyte layer in this document can be applied exactly as described in the descriptions of the second electrolyte composition and the second electrolyte layer.

[0190] Another embodiment of the present invention is a battery.

[0191] A battery may include a first electrode, a second electrode, a separator, and an electrolyte. The separator may be disposed between the first electrode and the second electrode. The polarity of the first electrode may be opposite to that of the second electrode. If the first electrode is a positive electrode (negative electrode), then the second electrode may be a negative electrode (positive electrode).

[0192] The system consisting of a battery separator and an electrolyte can be the battery separator of the present invention. Therefore, in the description of the battery, the description of the separator and electrolyte can be completely replaced by the battery separator described above.

[0193] The positive electrode can be the electrode that undergoes a reduction reaction during discharge. The negative electrode can be the electrode that undergoes an oxidation reaction during discharge.

[0194] The electrodes of the battery may include electrode active materials attached to the electrode current collector. Specifically, the electrodes may include an electrode current collector and an electrode active material layer disposed on one or both surfaces of the electrode current collector and containing the electrode active material.

[0195] The positive electrode active material in the electrode active material may include a lithium intercalation material. The lithium intercalation material may include lithium transition metal oxides. The lithium intercalation material may include lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide and lithium iron oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, lithium nickel manganese cobalt oxide, or combinations thereof. Preferably, the positive electrode active material may include lithium nickel manganese cobalt oxide.

[0196] The negative electrode active material in the electrode active material may include a lithium intercalation material. The lithium intercalation material may include lithium-based metals, including lithium metal and lithium alloys; carbon-based compounds, including carbon, petroleum coke, activated carbon, and graphite; or combinations thereof.

[0197] The positive current collector can be a foil of a metal including aluminum, nickel, or a combination thereof. Preferably, the positive current collector can be an aluminum foil.

[0198] The negative electrode current collector can be a foil containing metals including copper, gold, nickel, or combinations thereof. Preferably, the negative electrode current collector can be a copper foil.

[0199] When the battery is a lithium metal battery, the battery separator of the present invention may be more suitable. That is, the negative electrode may contain lithium metal. Specifically, the negative electrode may contain copper as the negative electrode current collector and may contain lithium metal as the negative electrode active material. In particular, the negative electrode may contain lithium metal as a major component (e.g., 90% by weight or more) as the negative electrode active material.

[0200] In this case, the first electrolyte layer can be positioned adjacent to the positive electrode.

[0201] As described above, the battery separator of the present invention may further include a second electrolyte layer disposed on another surface of the substrate layer. The second electrolyte layer may contain a second electrolyte composition.

[0202] In this configuration, the first electrolyte layer can be positioned adjacent to the positive electrode. The second electrolyte layer can be positioned adjacent to the negative electrode.

[0203] Therefore, problems caused by the expansion of the negative electrode during the charging and discharging of lithium metal batteries can be reduced, and battery performance can be improved.

[0204] Invention Embodiments

[0205] In the following document, the invention is described in more detail by way of examples and comparative examples. However, the invention is not limited to the examples.

[0206] Example 1. Battery separator

[0207] (1) 10 g of the first inorganic particles were dispersed in 20 g of water to prepare a dispersion. The first inorganic particles were ALK-L1 (Al2O3; D50: 300 nm; true density: 3.95 g / cm³) from Daehan Ceramics. 3 ).

[0208] (2) Add 0.1 g of thickener and 1 g of dispersant to the dispersion and stir with a homogenizer to prepare the first slurry. The thickener is CMC2020 (carboxymethyl cellulose; degree of substitution: 1.00; viscosity: 15 mPa·s) from WEALTHY. The dispersant is CSB-400 (acrylic acid copolymer; glass transition temperature: -25℃; viscosity: 30 cP; solids content: 40% by weight) from Toyochem.

[0209] (3) 10 g of the second inorganic particles were dispersed in 20 g of water to prepare a dispersion. The second inorganic particles were LLZO products (cubic Li) from Ganfeng Lithium. 6.4 La3Zr 1.4 Ta 0.6 O12 D50: 300±30 nm; Room temperature ionic conductivity: approximately 1.0 mS / cm.

[0210] (4) Add 0.1 g of thickener and 1 g of dispersant to the dispersion and stir with a homogenizer to prepare a second slurry. The thickener is CMC2020 (carboxymethyl cellulose; degree of substitution: 1.00; viscosity: 15 mPa·s) from WEALTHY. The dispersant is CSB-400 (acrylic acid copolymer; glass transition temperature: -25℃; viscosity: 30 cP; solids content: 40 wt%) from Toyochem.

[0211] (5) A solution was prepared by adding 3 g of binder, 3.5 g of first-1 crosslinking agent and 3.5 g of first-2 crosslinking agent to 90 g of liquid electrolyte, stirring the solution with a homogenizer, and then adding 0.02 g of photopolymerization initiator to the solution to prepare the first electrolyte composition. The binder was Kynar 2501-20 (PVDF-HFP; weight average molecular weight: 350,000 g / mol; HFP substitution rate: 18.6 wt%) from Arkema. The first-1 crosslinking agent was M340 (pentaerythritol triacrylate; PETA) from Miwon Specialty Chemical. The first-2 crosslinking agent was Miramer PU2100 (polyurethane diacrylate, weight average molecular weight: 1400) from Miwon Specialty Chemical. The photopolymerization initiator was Omnirad TPO-L ((2,4,6-trimethylbenzoyl)phenylphosphine ethyl ester) from IGM. The liquid electrolyte is a liquid electrolyte in which 1 M LiTFSI (LiN(CF3SO2)2) is dissolved in a non-aqueous solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 3:7, and 2% by weight of ethylene carbonate (VC) is added based on the total weight.

[0212] (6) The first slurry is applied to one surface of the substrate using a slit die and dried to prepare a structure comprising a first inorganic layer disposed on one surface of the substrate. The substrate is ND408 (8 μm thick PE film) from Asahi.

[0213] (7) Apply the second slurry to another surface of the substrate layer using a slit die and dry it to prepare a structure including a second inorganic layer disposed on another surface of the substrate layer.

[0214] (8) The first electrolyte composition is applied to the first inorganic layer and cured by UV irradiation to prepare a battery separator with a total thickness of 30 μm.

[0215] Example 2. Battery separator

[0216] The battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (8), the first electrolyte composition was applied to each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0217] Example 3. Battery separator

[0218] A battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (5), 5.6 g of first-1 crosslinking agent and 1.4 g of first-2 crosslinking agent were added, and in (8), the first electrolyte composition was applied to each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0219] Example 4. Battery separator

[0220] A battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (5), 1.4 g of first-1 crosslinking agent and 5.6 g of first-2 crosslinking agent were added, and in (8), the first electrolyte composition was applied to each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0221] Example 5. Battery separator

[0222] The battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (5), M300 (trimethylolpropane triacrylate) from Miwon Specialty Chemical was used as the first crosslinking agent, and in (8), the first electrolyte composition was applied to each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0223] Example 6. Battery separator

[0224] The battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (5), M300 (trimethylolpropane triacrylate) from Miwon Specialty Chemical was used as the first-1 crosslinking agent, 5.6 g of the first-1 crosslinking agent and 1.4 g of the first-2 crosslinking agent were added, and in (8), the first electrolyte composition was applied to each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0225] Comparative Example 1. Battery separator

[0226] The battery separator was prepared by repeating the same steps as in Example 1, except that in (6) and (7), the second slurry was applied to both surfaces of the substrate layer using a double-slit die and dried to prepare a structure comprising a second inorganic layer on both surfaces of the substrate layer.

[0227] Comparative Example 2. Battery separator

[0228] A battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (6) and (7), a second slurry was applied to the two surfaces of the substrate layer using a double-slit die and dried to prepare a structure comprising a second inorganic layer on the two surfaces of the substrate layer, and in (8), a first electrolyte composition was applied to the two surfaces of the structure and cured by UV irradiation.

[0229] Comparative Example 3. Battery separator

[0230] The battery separator was prepared by repeating the same steps as in Example 1, except that in (6) and (7), the first slurry was applied to both surfaces of the substrate layer using a double-slit die and dried to prepare a structure comprising a first inorganic layer on both surfaces of the substrate layer.

[0231] Comparative Example 4. Battery separator

[0232] A battery separator with a total thickness of 50 μm was prepared by repeating the same steps as in Example 1, except that in (6) and (7), a first slurry was applied to the two surfaces of the substrate layer using a double-slit die and dried to prepare a structure comprising a first inorganic layer on the two surfaces of the substrate layer, and in (8), a first electrolyte composition was applied to the two surfaces of the structure and cured by UV irradiation.

[0233] Comparative Example 5. Battery separator

[0234] A battery separator with a total thickness of 30 μm was prepared by repeating the same steps as in Example 1, except that in (6) and (7), a second slurry was applied to both surfaces of the substrate layer using a double-slit die and dried to prepare a structure comprising a second inorganic layer on both surfaces of the substrate layer, and in (8), a first electrolyte composition was applied to the other surface of the structure and cured by UV irradiation.

[0235] [Evaluate]

[0236] Experimental Example 1. Ion Conductivity

[0237] The ion conductivity of the battery separator is evaluated according to the following steps.

[0238] (1) A coin cell with the battery separator positioned between SUS plates, as in the embodiments and comparative examples, was manufactured. The coin cell was a 2016 type, and the area of ​​the battery separator was 2.83 cm². 2 (19 pi).

[0239] (2) The resistance and ionic conductivity of the coin cell were calculated by applying resistance measurements using electrochemical impedance spectroscopy (EIS) and converting them via the Nyquist plot method. The resistance measurements were performed at AC voltage with an amplitude of 10 mV and a frequency of 1,000,000 Hz to 1,000 Hz.

[0240] Experimental Example 2. Battery Performance

[0241] The discharge capacity and capacity retention of batteries manufactured using the battery separators of the examples and comparative examples were measured using the following steps.

[0242] (1) Preparation of such a slurry: wherein a mixture consisting of 94 wt% LiNiCoMnO2 (Ni:Co:Mn=8:1:1) as the positive electrode active material, 3 wt% conductive carbon black (Super P; IMERYS Graphite & Carbon) as the conductive material and 3 wt% polyvinylidene fluoride with a weight average molecular weight of about 800,000 as the binder is uniformly dispersed in NMP (N-methyl-2-pyrrolidone).

[0243] (2) The slurry was prepared at 4.0 mAh / cm 2 The loading amount is applied to a surface of a 20 μm thick aluminum current collector, followed by drying and rolling to prepare a positive electrode plate with a positive electrode active material layer on top.

[0244] (3) The positive electrode plate is stamped to 1.54 cm. 2 The size is (14 pi).

[0245] (4) Lithium metal (negative electrode active material layer) is rolled onto a 10 μm thick copper plate to prepare a negative electrode plate with a total thickness of 100 μm.

[0246] (5) The negative electrode plate is stamped to 1.76 cm. 2 The size is (15 pi).

[0247] (6) Fabrication of an electrode assembly having such a structure that the positive active material layer of the positive electrode plate and the negative active material layer of the negative electrode plate are arranged facing each other and cut into 2.83 cm sections. 2 A battery separator of size (19 pi) is disposed between the positive electrode active material layer and the negative electrode active material layer.

[0248] (7) The electrode assembly is housed in a bag to complete the battery. Five battery samples are prepared. The performance of the battery is the arithmetic mean of the five samples.

[0249] Prepare the electrochemical analyzer (Toyo, Toscat-3100).

[0250] (8) Charge the battery in CC-CV mode at 0.2 C, 4.3 V and cut-off 0.05 C, and discharge the battery at 0.5 C, 3.0 V and cut-off 0.05 C.

[0251] (9) Measure the initial (first cycle) charging capacity and discharging capacity.

[0252] (10) Measure the charging capacity and discharging capacity after repeating 50 cycles.

[0253] [Results and Discussion]

[0254] Table 1 below shows the test results for the embodiments and comparative examples.

[0255] [Table 1]

[0256]

Claims

1. A battery separator, comprising: basal layer; A first inorganic layer disposed on one surface of the substrate layer and containing first inorganic particles; A second inorganic layer disposed on another surface of the substrate layer and comprising second inorganic particles; and A first electrolyte layer disposed on one surface of the first inorganic layer and comprising a first electrolyte composition. The first inorganic particles include flame-retardant inorganic particles, and The second inorganic particle includes lithium-ion transport inorganic particles.

2. The battery separator according to claim 1, The first inorganic particles include SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, Zn2SnO4, ZnSnO3, ZnSn(OH)6, ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or combinations thereof.

3. The battery separator according to claim 1, The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle are each independently in the range of 100 to 1000.

4. The battery separator according to claim 1, The true density (g / cm³) of the first inorganic particle 3 The density of the inorganic particles is less than the true density (g / cm³) of the second inorganic particles. 3 ).

5. The battery separator according to claim 1, The second inorganic particle includes Li x Ti y (PO4)3(0 <x<2,0<y<3);Li x Al y Ti z (PO4)3(0 <x<2,0<y<1,0<z<3);Li x La y TiO3 (0 <x<2,0<y<3);Li 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2); or combinations thereof.

6. The battery separator according to claim 1, The second inorganic particle comprises a garnet-type crystal structure.

7. The battery separator according to claim 1, The second inorganic particle includes Li 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

8. The battery separator according to claim 1, The base layer comprises a polyolefin-based membrane.

9. The battery separator according to claim 1, The first electrolyte composition comprises a first binder, a first liquid electrolyte, and a first crosslinking agent.

10. The battery separator according to claim 9, The first adhesive comprises a first unit of vinylidene fluoride and a second unit of a fluorinated alkyl vinyl compound.

11. The battery separator according to claim 9, The adhesive has a weight-average molecular weight (g / mol) in the range of 150,000 to 600,000, and The content (by weight%) of the second unit of the adhesive is in the range of 10 to 25%.

12. The battery separator according to claim 9, The first liquid electrolyte contains a non-aqueous solvent, a lithium salt, and additives.

13. The battery separator according to claim 12, The non-aqueous solvents mentioned above include carbonate-based compounds.

14. The battery separator according to claim 13, The first electrolyte layer contains a linear carbonate-based compound with a volume larger than that of a cyclic carbonate-based compound.

15. The battery separator according to claim 14, The linear carbonate-based compounds mentioned above include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl ethyl carbonate, or combinations thereof.

16. The battery separator according to claim 14, The linear carbonate-based compound is a liquid at room temperature.

17. The battery separator according to claim 14, The compounds based on cyclic carbonates include ethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butyl carbonate, or combinations thereof.

18. The battery separator according to claim 14, The cyclic carbonate-based compound is a solid at room temperature.

19. The battery separator according to claim 14, The volume (volume %) of the linear carbonate-based compound in the first electrolyte layer is in the range of 55 to 95%.

20. The battery separator according to claim 9, The first crosslinking agent comprises a first-1 crosslinking agent and a first-2 crosslinking agent with different numbers of crosslinkable functional groups, and The number of crosslinkable functional groups in the first-1 crosslinking agent is greater than the number of crosslinkable functional groups in the first-2 crosslinking agent.

21. The battery separator according to claim 20, The first-1 crosslinking agent has 3 or more crosslinkable functional groups.

22. The battery separator according to claim 20, The first-1 crosslinking agent includes compounds based on tri(meth)acrylate, compounds based on tetra(meth)acrylate, compounds based on penta(meth)acrylate, compounds based on hexa(meth)acrylate, or combinations thereof.

23. The battery separator according to claim 20, The first-1 crosslinking agent includes a monomer compound.

24. The battery separator according to claim 20, The first-1 crosslinking agent includes trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, ethoxylated glycerol tri(meth)acrylate, propoxylated glycerol tri(meth)acrylate, tris(2-hydroxyethyl) isocyanurate tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, Ethoxylated pentaerythritol tetra(meth)acrylate, propoxylated pentaerythritol tetra(meth)acrylate, erythritol tetra(meth)acrylate, bis(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ethoxylated dipentaerythritol penta(meth)acrylate, sorbitol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, sorbitol hexa(meth)acrylate, or combinations thereof.

25. The battery separator according to claim 20, The first-2 crosslinking agent has 2 functional groups.

26. The battery separator according to claim 20, The first-2 crosslinking agent includes a compound based on di(meth)acrylate.

27. The battery separator according to claim 20, The first-2 crosslinking agent includes a polymer compound.

28. The battery separator according to claim 20, The first-2 crosslinking agents include polyethylene glycol di(meth)acrylate, poly(ethylene oxide-propylene oxide) di(meth)acrylate, polyurethane di(meth)acrylate, polycarbonate di(meth)acrylate, or combinations thereof.

29. The battery separator according to claim 20, The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) in the first electrolyte layer to the weight of the first-2 crosslinking agent (C1-2) in the first electrolyte layer is in the range of 1:9 to 9:

1.

30. The battery separator according to claim 1, The battery separator further includes a second electrolyte layer disposed on another surface of the substrate layer and containing a second electrolyte composition.

31. A battery, comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The separator comprises a base layer; a first inorganic layer disposed on one surface of the base layer and containing first inorganic particles; a second inorganic layer disposed on the other surface of the base layer and containing second inorganic particles; and a first electrolyte layer disposed on one surface of the first inorganic layer and containing a first electrolyte composition. The first inorganic particles include flame-retardant inorganic particles, and The second inorganic particle includes lithium-ion transport inorganic particles.

32. The battery according to claim 31, The negative electrode contains lithium metal, and The first electrolyte layer is positioned adjacent to the positive electrode.

33. The battery according to claim 31, The separator further includes a second electrolyte layer disposed on another surface of the substrate layer and containing a second electrolyte composition. The negative electrode contains lithium metal. The first electrolyte layer is positioned adjacent to the positive electrode, and The second electrolyte layer is positioned adjacent to the negative electrode.

Images