Battery separator and battery

Abstract

A battery separator and a battery of the present invention may comprise: a base layer; a first inorganic layer positioned on one surface of the base layer and comprising first inorganic particles; a second inorganic layer positioned on the other surface of the base layer and comprising second inorganic particles; and a first electrolyte layer positioned on one surface of the first inorganic layer and comprising a first electrolyte composition, wherein the first inorganic particles may comprise flame-retardant inorganic particles, and the second inorganic particles may comprise lithium ion conductive inorganic particles.

Description

Battery separator, and battery

[0001] This document claims the benefit of the priority date of Application No. 10-2024-0189028 filed with the Korean Intellectual Property Office on December 17, 2024, and incorporates the entire contents thereof by reference.

[0002] The present invention is a battery separator.

[0003] The present invention is a battery.

[0004] Gel polymer electrolytes (GPEs) may include a binder and a liquid electrolyte. Gel polymer electrolytes are typically incorporated into electrodes in batteries and can be combined with electrode active materials. In this case, a polyolefin-based film may be positioned between the electrodes (positive and negative electrodes) to act as a separator that prevents physical short circuits between the electrodes.

[0005] A lithium metal battery is a battery that contains lithium metal as the negative electrode active material.

[0006] The negative electrode of a lithium metal battery can expand during the charging and discharging process. The negative electrode may form lithium dendrites due to uneven electrodeposition during the charging and discharging process. The expanded negative electrode and / or lithium dendrites can cause cracks in the positive electrode. Cracks in the positive electrode can adversely affect battery performance. Excellent battery performance can be ensured by suppressing the expansion of the negative electrode and / or the formation of lithium dendrites, or by preventing cracks in the positive electrode even if the negative electrode expands or lithium dendrites are formed.

[0007] One embodiment of the present invention is a battery separator comprising: a substrate layer; a first inorganic layer located on one side of the substrate layer and comprising a first inorganic particle; a second inorganic layer located on the other side of the substrate layer and comprising a second inorganic particle; and a first electrolyte layer located on one side of the first inorganic layer and comprising a first electrolyte composition, wherein the first inorganic particle comprises a flame-retardant inorganic particle and the second inorganic particle comprises a lithium ion-transmitting inorganic particle.

[0008] The first inorganic particle above 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 a combination thereof.

[0009] The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle may each independently be within a range of 100 to 1000.

[0010] True density (g / cm²) of the first inorganic particle above 3 ) is the true density (g / cm²) of the second inorganic particle mentioned above. 3 It can be smaller than ).

[0011] The above second inorganic particle is 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 a combination thereof may be included.

[0012] The above second inorganic particle may include a garnet-type crystal structure.

[0013] The above second inorganic particle is Li 6+x La3Zr 2-y M y O 12-z It may include (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

[0014] The above substrate layer may include a polyolefin-based film.

[0015] The first electrolyte composition may include a first binder, a first liquid electrolyte, and a first crosslinking agent.

[0016] The first binder above may include a first unit of vinylidene fluoride and a second unit of a fluorine-containing alkyl vinyl compound.

[0017] The weight average molecular weight (g / mol) of the binder may be in the range of 150,000 to 600,000, and the second unit content (weight%) of the binder may be in the range of 10 to 25.

[0018] The first liquid electrolyte may include a non-aqueous solvent, a lithium salt, and an additive.

[0019] The above-mentioned non-aqueous solvent may include a carbonate-based compound.

[0020] The first electrolyte layer above may contain a linear carbonate compound in a larger volume than a cyclic carbonate compound.

[0021] The above linear carbonate-based compound may include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylmethyl carbonate, or a combination thereof.

[0022] The above linear carbonate-based compound may be liquid at room temperature.

[0023] The above-mentioned cyclic carbonate compounds may include vinylethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butylene carbonate, or a combination thereof.

[0024] The above cyclic carbonate compound may be solid at room temperature.

[0025] The volume (volume%) of the linear carbonate-based compound in the first electrolyte layer may be in the range of 55 to 95.

[0026] The first crosslinking agent comprises a first-1 crosslinking agent and a first-2 crosslinking agent having 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.

[0027] The number of crosslinkable functional groups of the above 1-1 crosslinking agent may be 3 or more.

[0028] The above-mentioned 1-1 crosslinking agent may include a tri(meth)acrylate compound, a tetra(meth)acrylate compound, a penta(meth)acrylate compound, a hexa(meth)acrylate compound, or a combination thereof.

[0029] The above-mentioned 1-1 crosslinking agent may include a monomeric compound.

[0030] The above 1-1 crosslinking agent is 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, ditrimethylolpropane tetra(meth)acrylate, It may include 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 a combination thereof.

[0031] The number of functional groups of the above 1st and 2nd crosslinking agents may be 2.

[0032] The above first and second crosslinking agents may include di(meth)acrylate-based compounds.

[0033] The above first and second crosslinking agents may include polymeric compounds.

[0034] The above first and second 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 a combination thereof.

[0035] The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) of the first electrolyte layer and the weight of the first-2 crosslinking agent (C1-2) of the first electrolyte layer may be in the range of 1:9 to 9:1.

[0036] The battery separator may further include a second electrolyte layer located on the other side of the substrate layer and comprising a second electrolyte composition.

[0037] Another embodiment of the present invention comprises a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the separator comprises a substrate layer; a first inorganic layer located on one side of the substrate layer and comprising a first inorganic particle; a second inorganic layer located on the other side of the substrate layer and comprising a second inorganic particle; and a first electrolyte layer located on one side of the first inorganic layer and comprising a first electrolyte composition; wherein the first inorganic particle comprises a flame-retardant inorganic particle and the second inorganic particle comprises a lithium ion-transmitting inorganic particle.

[0038] The above cathode includes lithium metal, and the first electrolyte layer may be located adjacent to the anode.

[0039] The above separator is located on the other side of the substrate layer and further comprises a second electrolyte layer comprising a second electrolyte composition; the cathode comprises lithium metal, the first electrolyte layer is located adjacent to the anode, and the second electrolyte layer may be located adjacent to the cathode.

[0040] The battery separator of the present invention may have one side of charge carrier (e.g., lithium ion) transferability and the other side of high elasticity.

[0041] The battery of the present invention can protect the positive electrode and simultaneously exhibit excellent electrical performance.

[0042] This document may use ordinal numbers such as “first” and “second” when referring to multiple components. There is no priority among the components.

[0043] In this document, if a specific commercially available product is used as an ingredient, the characteristics of that ingredient may refer to the characteristics listed in the product's Technical Data Sheet (TDS) or Certification of Analysis (COA).

[0044] In this document, if the physical properties of a specific material vary depending on temperature and pressure, the measurement standards for those properties may be room temperature (25 ℃) and atmospheric pressure (101.325 kPa). This is in accordance with the Standard Ambient Temperature and Pressure (SATP) defined in the CRC Chemical and Physical Handbook.

[0045] In this document, the numerical range “within the range of A to B” means “A or greater and B or less.”

[0046] The numbers mentioned in this document are rounded values. For example, 1.5 is a number within the range of 1.45 to 1.54.

[0047] The present document describes the invention in more detail below.

[0048] One embodiment (Embodiment) of the present invention is a battery separator.

[0049] In this document, a battery may include any element that performs an electrochemical reaction.

[0050] The above battery may refer to any type of primary battery, secondary battery, fuel battery, solar battery, or capacitor, etc. The above battery may refer to a lithium secondary battery. The above lithium secondary battery may include a lithium metal secondary battery, a lithium polymer secondary battery, a lithium ion polymer secondary battery, or a lithium ion secondary battery, etc.

[0051] The battery separator may be located between the electrodes in the battery. The battery separator may be located between the positive and negative electrodes in the battery. The battery separator may prevent physical contact (short circuit) between the positive and negative electrodes in the battery. A charge carrier (e.g., lithium ions) may move through the battery separator between the electrodes.

[0052] The battery separator of the present invention comprises a substrate layer; an inorganic layer; and a first electrolyte layer. The separator may further comprise a second electrolyte layer. The second electrolyte layer is described later.

[0053] The above substrate layer can cause a fluid to move from one side of the substrate layer to another side.

[0054] The above inorganic layer comprises inorganic particles. The inorganic particles may impart specific properties to the battery separator. For example, the inorganic particles may impart lithium ion mobility performance to the battery separator, and / or impart thermal properties (heat resistance, flame retardancy, etc.).

[0055] The first electrolyte layer above can provide a path for a charge carrier to move to the battery separator.

[0056] The above-mentioned inorganic layer comprises a plurality of inorganic layers containing different inorganic particles. The above-mentioned inorganic layer comprises a first inorganic layer and a second inorganic layer. The first inorganic layer comprises a first inorganic particle. The second inorganic layer comprises a second inorganic particle. The first inorganic particle and the second inorganic particle exhibit different characteristics.

[0057] The first inorganic layer is located on one side of the substrate layer. The second inorganic layer is located on the other side facing the one side of the substrate layer. Specifically, the first inorganic layer may be located on the first side of the substrate layer, and the second inorganic layer may be located on the second side facing the first side of the substrate layer. The thicknesses of the first inorganic layer and the second inorganic layer may be the same or different.

[0058] The first electrolyte layer is located on one side of the first inorganic layer. That is, the first electrolyte layer is located on one side of the substrate layer, and the first inorganic layer is located between the substrate layer and the first electrolyte layer.

[0059] The above electrolyte layer comprises an electrolyte composition. The composition included in the first electrolyte layer is the first electrolyte composition. The composition included in the second electrolyte layer is the second electrolyte composition. The above electrolyte composition may be a composition of a gel polymer electrolyte.

[0060] In this document, the gel polymer electrolyte is an electrolyte in the gel phase 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 ion conductivity to the gel polymer electrolyte.

[0061] In this document, an electrolyte composition refers to a composition that can become an electrolyte either by itself or through a specific reaction.

[0062] The above first inorganic particle includes flame-retardant inorganic particles.

[0063] The above flame-retardant inorganic particles can add flame-retardant properties to the battery separator and prevent a rapid rise in the internal temperature of the battery.

[0064] The above second inorganic particle includes a lithium ion-transmitting inorganic particle.

[0065] Lithium ion-transporting inorganic particles contain lithium but can perform the function of transporting lithium ions without storing lithium. There may be a type of defect inside the lithium ion-transporting inorganic particles. Charge carriers, such as lithium ions, can move by utilizing said defects. Therefore, the lithium ion-transporting inorganic particles can improve the lithium ion conductivity within the battery. As a result, the performance of the battery can also be improved.

[0066] The battery separator of the present invention can mitigate the volume expansion of the electrode by arranging flame-retardant inorganic particles adjacent to the electrolyte layer, and reduce adverse reactions with the electrode by arranging lithium ion-transmitting inorganic particles on the opposite side.

[0067] Although not limited to theory, the arrangement of inorganic particles can reduce damage caused by volume expansion of adjacent electrodes. Additionally, since lithium-ion-carrying inorganic particles can reduce side reactions with the electrodes, it is believed that placing non-lithium-ion-carrying inorganic particles on one side and lithium-ion-carrying inorganic particles on the opposite side can effectively reduce battery degradation caused by electrode volume expansion and side reactions.

[0068] The battery separator of the present invention, in which two inorganic layers with opposite characteristics are arranged to face each other in a substrate layer, may be particularly suitable for batteries requiring opposite characteristics for the positive and negative electrodes.

[0069] For example, the negative electrode of a lithium metal battery containing lithium metal as the negative electrode may expand during the charging and discharging process, causing cracks in the positive electrode. Here, the first inorganic layer of the battery separator of the present invention may be located on the positive electrode side, and the second inorganic layer may be located on the negative electrode side. The formation of lithium dendrites can be suppressed by the second inorganic layer, and even if they are formed, cracks in the positive electrode can be reduced by the first inorganic layer.

[0070] Although not limited to theory, the arrangement of inorganic particles can reduce damage caused by the volume expansion of the cathode. Additionally, since lithium-ion-carrying inorganic particles can reduce side reactions with the cathode, it is believed that placing non-lithium-ion-carrying inorganic particles on the side facing the anode and lithium-ion-carrying inorganic particles on the side facing the cathode can prevent anode damage caused by cathode volume expansion and effectively reduce battery degradation caused by side reactions with the cathode.

[0071] Below, this document describes the battery separator in more detail.

[0072] The first inorganic particle 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 a combination thereof. Preferably, the first inorganic particle may include ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or a combination thereof. More preferably, the first inorganic particle may include Al2O3, AlOOH, Al(OH)3, TiO2, or a combination thereof.

[0073] The D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle may each independently be within a range of 100 to 1000.

[0074] Specifically, the D50(nm) of the first inorganic particle and the D50(nm) of the second inorganic particle may each independently be 150 or more, 200 or more, 250 or more, 300 or more, 350 or more, 400 or more, 450 or more, or 500 or more. The D50(nm) of the first inorganic particle and the D50(nm) of the second inorganic particle may 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.

[0075] The true density of the first inorganic particle may be lower than the true density of the second inorganic particle. The inorganic particles can improve the mechanical and thermal properties of the battery separator by imparting rigidity and heat resistance to the battery separator. If the battery separator contains multiple inorganic particles with different densities, the heavier particles can form a framework at the bottom, while the lighter particles can fill the gaps formed by the heavier particles or at the top; in this process, a uniform pore structure can be formed inside the battery separator. A uniform pore structure can increase the electrolyte impregnation and ion conductivity of the battery separator.

[0076] In this document, a uniform pore structure may refer to a structure in which the average size, shape, and density of the pores are nearly constant regardless of the position of the layer, thereby maintaining a constant material transport path within it. A uniform pore structure may refer to a state in which the variation in the size distribution and spatial distribution of the pores is small throughout the battery separator containing the pores, the pores are continuously connected to one another, and the pores are not localized in a specific direction or position.

[0077] In this document, the true density of a particle may refer to the density calculated solely from the mass and volume of the particle itself, excluding voids within the particle. The true density of the inorganic particle may be a known value for the inorganic particle or a value measured according to known methods. The true density of the inorganic particle may be determined by the chemical composition of the inorganic particle.

[0078] True density (g / cm²) of the first inorganic particle above 3 ) may be in the range of 1.5 to 6. Specifically, the true density (g / cm³) of the first inorganic particle is 3 ) may be 2.0 or higher, 2.5 or higher, 3.0 or higher, 3.5 or higher, or 3.95 or higher. The true density (g / cm³) of the first inorganic particle above. 3 ) may 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.

[0079] True density (g / cm²) of the above second inorganic particle 3 ) may be in the range of 2.5 to 10. The true density (g / cm³) of the second inorganic particle is 3 ) may be 3.0 or higher, 3.5 or higher, 4.0 or higher, 4.5 or higher, 5.0 or higher, 5.4 or higher, 5.5 or higher, 6.0 or higher, or 6.5 or higher. The true density (g / cm³) of the second inorganic particle above. 3 ) may 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.

[0080] The above second inorganic particle is 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), Li6+x La3Zr 2-y M y O 12-z It may include (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2), or a combination thereof. Preferably, the second inorganic particle is Li 6+x La3Zr 2-y M y O 12-z It may include (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

[0081] The above second inorganic particle may include a garnet-type crystal structure.

[0082] Garnet-type crystal structures can have a cubic structure. The above garnet-type crystal structure is A3B5O 12 It may have a structure of the form A3B2(SiO4)3. The above A may include divalent, trivalent, or tetravalent ions of La, Ca, or Y. The above B may include tetravalent ions of Zr or Al. Through this, the garnet-type crystal structure can form a stable structure.

[0083] The above Li 6+x La3Zr 2-y M y O 12-z (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2) is referred to as an LLZO-based compound, which is a compound having a representative garnet-type crystal structure. In addition to the LLZO-based compound, the above garnet-type crystal structure includes Li5La3Nb2O 12 , Li6CaLa2Nb2O 12 , Li5La3Ta2O 12 , Li5La3M2O 12 It may include (M = Nb, Ta, Sb, etc.).

[0084] The above garnet-type crystal structure can be advantageous in that it provides a pathway for the movement of lithium ions, exhibiting high ionic conductivity, excellent high-temperature thermal stability, and low chemical reactivity. Since the second inorganic particle has a garnet-type crystal structure, the capacity characteristics and stability of a battery containing the second inorganic particle can be improved.

[0085] The first inorganic layer may include only the first inorganic particle as an inorganic particle. Additionally, the second inorganic layer may include only the second inorganic particle as an inorganic particle. That is, the inorganic particles of the first inorganic layer and the second inorganic layer, respectively, may consist of the first inorganic particle and the second inorganic particle. For example, the first inorganic layer and the second inorganic layer may not each independently include a combination of the first inorganic particle and the second inorganic particle.

[0086] The above substrate layer may include a polyolefin-based film. Specifically, the above substrate layer may include a porous polyolefin-based film.

[0087] Here, a polyolefin-based porous film refers to a porous film containing a polyolefin-based resin as a main component.

[0088] The above polyolefin-based porous film may contain the polyolefin-based resin in an amount of 50 volume% or more, 90 volume% or more, or 95 volume% or more of the total material constituting the polyolefin-based porous film.

[0089] The weight average molecular weight of the component included in the above polyolefin resin is 3×10 5 Up to 15×10 6 It may be possible. If the weight average molecular weight of the component included in the above polyolefin resin is 1 million or more, the strength of the separator including the above polyolefin porous film may be improved.

[0090] The above polyolefin resin may include a thermoplastic resin. The above thermoplastic resin may include a homopolymer (e.g., polyethylene, polypropylene, polybutene) or copolymer (e.g., ethylene-propylene copolymer) formed by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and 1-hexene.

[0091] The above polyolefin-based porous film may be a layer comprising only these polyolefin-based resins, or a layer comprising two or more of these polyolefin-based resins. Among these, polyethylene and high molecular weight polyethylene having ethylene as a main backbone can stop (shut down) the flow of excessive current at a lower temperature. In addition, the polyolefin-based porous film may additionally include components other than polyolefin-based resins that do not impair the function of the film.

[0092] The first electrolyte composition may include a first binder, a first liquid electrolyte, and a first crosslinking agent.

[0093] The first binder can form a polymer matrix alone or together with the first crosslinking agent.

[0094] The first liquid electrolyte can be impregnated into the polymer matrix formed by the first binder. The first liquid electrolyte can impart ion conductivity to the gel polymer electrolyte.

[0095] The first crosslinking agent may form a polymer matrix in a gel polymer electrolyte alone or together with the first binder. The first crosslinking agent may link the first binders and / or the first crosslinking agents in the polymer matrix.

[0096] The first binder can form a framework in the first electrolyte layer formed by the first electrolyte composition. The first binder has appropriate crystallinity and polarity to increase the ion conductivity of the battery separator. In particular, the polar portion of the first binder can combine with the first crosslinking agent. At this time, the first binder can form a crosslinked structure in the first electrolyte layer.

[0097] The first binder above may include a fluorine-based binder. The fluorine-based binder may refer to a binder whose constituent unit contains fluorine as part or all. The fluorine-based binder may include a PVDF-based binder.

[0098] The above PVDF-based binder may be a homopolymer or copolymer comprising a polymerization unit derived from vinylidene fluoride. The above fluorine-based binder may comprise a first unit of vinylidene fluoride and a second unit of a fluorine-containing alkyl vinyl compound. The above PVDF-based binder may be a block copolymer or a random copolymer comprising the first unit and the second unit. Preferably, the above PVDF-based binder may be a random copolymer comprising the first unit and the second unit.

[0099] The above fluorine-containing alkyl vinyl compound is C n H (2n+1-y) F y It may mean a compound in which at least one fluorine-containing alkyl group represented by is bonded to a vinyl group. However, vinylidene fluoride is excluded.

[0100] The fluorine-containing alkyl vinyl compound may include one or more selected from the group consisting of vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene. Preferably, the fluorine-containing alkyl vinyl compound may include one or more selected from the group consisting of hexafluoropropylene, tetrafluoroethylene, and chlorotrifluoroethylene. More preferably, the fluorine-containing alkyl vinyl compound may include hexafluoropropylene.

[0101] The second unit content of the above-mentioned fluorine-based binder can be adjusted. The second unit content of the above-mentioned fluorine-based binder may affect the crystallinity of the above-mentioned fluorine-based binder, the ionic conductivity of the above-mentioned battery separator, and the mechanical strength.

[0102] The second unit content (weight%) of the above fluorine-based binder may be in the range of 10 to 25. Preferably, the second unit content (weight%) of the above fluorine-based binder may be 15 or more, 16 or more, 17 or more, or 18 or more. The second unit content (weight%) of the above fluorine-based binder may be 23 or less, 21 or less, 20 or less, or 19 or less.

[0103] The first and second unit contents of the above fluorine-based binder are relative to the above fluorine-based binder 19 It can be measured by F-NMR analysis.

[0104] The weight-average molecular weight of the fluorine-based binder can also be controlled. The weight-average molecular weight (g / mol) of the fluorine-based binder may be in the range of 150,000 to 600,000. Preferably, the weight-average molecular weight (g / mol) of the fluorine-based binder may be 200,000 or more, 250,000 or more, 300,000 or more, or 350,000 or more. The weight-average molecular weight (g / mol) of the fluorine-based binder may be 550,000 or less, 500,000 or less, 450,000 or less, 400,000 or less, or 350,000 or less.

[0105] The weight average molecular weight of the above fluorine-based binder can be measured by gel permeation chromatography.

[0106] The melting point of the above fluorine-based binder can also be controlled. The melting point (°C) of the above fluorine-based binder may be in the range of 100 to 140. Preferably, the melting point (°C) of the above fluorine-based binder may be 110 or higher, or 115 or higher. The melting point (°C) of the above fluorine-based binder may be 135 or lower, 130 or lower, or 125 or lower.

[0107] The first liquid electrolyte may be impregnated into the first binder, specifically the polymer matrix formed by the first binder. The first liquid electrolyte may further include a non-aqueous solvent, a lithium salt, and an additive.

[0108] The above-mentioned non-aqueous solvent may refer to an organic solvent that does not contain water or contains a trace amount of water. The above-mentioned non-aqueous solvent may include carbonate compounds, ether compounds, ester compounds, compounds containing polar functional groups, or mixtures thereof. Preferably, the above-mentioned non-aqueous solvent may include carbonate compounds.

[0109] The above ether-based compound may include dimethoxyethane, diethoxyethane, tetrahydrofuran, or a combination thereof.

[0110] The above ester compound may include N-methyl-2-pyrrolidone (NMP), gamma-butyrolactone (γ-butyrolactone), or a combination thereof.

[0111] The above-mentioned polar functional group-containing compound may include dimethyl sulfoxide, acetonitrile, or a combination thereof.

[0112] The above carbonate-based compound may include a linear carbonate-based compound, a cyclic carbonate-based compound, or a combination thereof. Preferably, the carbonate-based compound may include a linear carbonate-based compound and a cyclic carbonate-based compound.

[0113] The first electrolyte layer may contain a linear carbonate-based compound in a larger volume than a cyclic carbonate-based compound. In this case, the miscibility of the binder with respect to the liquid electrolyte is increased, and an abnormal increase in viscosity of the first electrolyte composition can be prevented.

[0114] The volume of the carbonate-based compound in the above electrolyte layer can be controlled by the volume of the carbonate-based compound in the above electrolyte composition.

[0115] In this document, linear carbonate compounds refer to open double esters of carbonic acid. Specifically, linear carbonate compounds include structures in which the two hydroxyl groups of carbonic acid are esterified to different alcohols, and the entire molecule does not form a ring.

[0116] In this document, cyclic carbonate compounds refer to internal esters in which the -O-CO-O- backbone of carbonate groups is contained within a ring structure. Specifically, cyclic carbonate compounds include a structure in which the two ends of two hydroxyl groups within a molecule form ester bonds with the same carbonate group, thereby containing the -O-CO-O- backbone within a ring.

[0117] The above linear carbonate-based compound may include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylmethyl carbonate, or a combination thereof.

[0118] Specifically, the linear carbonate-based compound may include dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, or a combination thereof.

[0119] More specifically, the linear carbonate-based compound may include ethylmethyl carbonate.

[0120] The above linear carbonate-based compound may be liquid at room temperature.

[0121] The above-mentioned cyclic carbonate compounds may include vinylethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butylene carbonate, or a combination thereof.

[0122] Specifically, the cyclic carbonate compound may include vinylethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, propylene carbonate, butylene carbonate, or a combination thereof.

[0123] More specifically, the cyclic carbonate compound may include vinylethylene carbonate, vinylene carbonate, ethylene carbonate, propylene carbonate, or a combination thereof.

[0124] From the perspective of the miscibility of the aforementioned first binder and the first liquid electrolyte, the control of the viscosity of the first electrolyte composition, and the safety of the battery, it may be desirable for the phases of the linear carbonate-based compound and the cyclic carbonate-based compound to be combined differently.

[0125] The above cyclic carbonate-based compound may be solid at room temperature. Specifically, the above cyclic carbonate-based compound may include ethylene carbonate.

[0126] The amount of the above-mentioned linear carbonate compounds and cyclic carbonate compounds can also be appropriately controlled within a range that satisfies the above conditions.

[0127] The volume (volume%) of the linear carbonate-based compound in the first electrolyte layer may be in the range of 55 to 95.

[0128] Preferably, the volume (volume%) of the linear carbonate-based compound in the first electrolyte layer may be 60 or more, 65 or more, or 70 or more. The volume (volume%) of the linear carbonate-based compound in the first electrolyte layer may be 90 or less, 85 or less, 80 or less, or 75 or less.

[0129] The volume (volume%) of the cyclic carbonate-based compound in the first electrolyte layer may be in the range of 5 to 45. Preferably, the volume (volume%) of the cyclic carbonate-based compound in the first electrolyte layer may be 10 or more, 15 or more, 20 or more, or 25 or more. The volume (volume%) of the cyclic carbonate-based compound in the first electrolyte layer may be 40 or less, 35 or less, or 30 or less.

[0130] The above lithium salt may be soluble in the above non-aqueous solvent. The above lithium salt may refer to a material that decomposes into lithium cations and anions upon dissociation.

[0131] The above lithium salt may include LiPF6, LiBF4, LiCl, LiBr, LiI, LiClO4, LiAsF6, LiCH3CO2, LiCF3SO3, LiN(CF3SO2)2, LiN(FSO2)2, LiC(CF2SO2)3, or a combination thereof. Preferably, the lithium salt may include LiN(CF3SO2)2.

[0132] The above additive may refer to a substance applied in small amounts to a liquid electrolyte for the purpose of stabilizing the electrode interface, improving electrochemical stability, controlling conductivity characteristics, improving temperature characteristics, suppressing gas generation, etc.

[0133] The above additive may include vinylene carbonate, 1,3-propane sulfone, 1,3-propene sulfone, lithium difluorophosphate, lithium tetrafluoro(oxaleto)phosphate, lithium bis(fluorosulfonyl)imide, fluoroethylene carbonate, vinyl ethylene carbonate, or a combination thereof. Preferably, the above additive may include vinylene carbonate.

[0134] Since the first liquid electrolyte is impregnated into the first binder or the polymer matrix formed by the first binder in the first electrolyte layer, the thickness of the first electrolyte layer may generally be thick. Specifically, the first electrolyte layer may be thicker than the substrate layer.

[0135] The first crosslinking agent comprises multiple types of crosslinking agents. Specifically, the first crosslinking agent may include a first-1 crosslinking agent and a first-2 crosslinking agent having different numbers of crosslinkable functional groups. 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. Here, the number of crosslinkable functional groups of a 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 that act to connect binders and / or crosslinking agents in the polymer matrix.

[0136] If the first electrolyte composition comprises a plurality of crosslinking agents having different numbers of crosslinkable functional groups, the first electrolyte layer can be formed at a rapid crosslinking rate and can exhibit high crosslinking density and appropriate flexibility.

[0137] Although not limited to theory, it is believed that the excellent characteristics of the above electrolyte layer, such as the crosslinking rate, crosslinking density, and flexibility, are due to the fact that the first-1 crosslinking agent can form a dense crosslinking structure and the first-2 crosslinking agent can provide a space for the liquid electrolyte to be impregnated.

[0138] The number of crosslinkable functional groups of the above-mentioned 1-1 crosslinking agent may be 3 or more. In this case, the above-mentioned 1-1 crosslinking agent may form a dense crosslinking structure. Specifically, the number of crosslinkable functional groups of the above-mentioned 1-1 crosslinking agent may be 6 or less, 5 or less, or 4 or less.

[0139] The above-mentioned crosslinking functional group may include a photoreactive functional group. Specifically, the above-mentioned crosslinking functional group may include a (meth)acryloyl group as a photoreactive functional group. The above-mentioned first-1 crosslinking agent and the above-mentioned first-2 crosslinking agent may include a polyfunctional (meth)acrylate-based compound. Preferably, from the viewpoint of preventing deterioration of electrochemical properties due to the rate of the crosslinking reaction and the stiffness of the polymer network, the above-mentioned crosslinking functional group may include an acryloyl group as a photoreactive functional group.

[0140] Accordingly, the above-mentioned 1-1 crosslinking agent may include a tri(meth)acrylate compound, a tetra(meth)acrylate compound, a penta(meth)acrylate compound, a hexa(meth)acrylate compound, or a combination thereof.

[0141] Specifically, the 1-1 crosslinking agent may include a triacrylate compound, a tetraacrylate compound, a pentaacrylate compound, a hexaacrylate compound, or a combination thereof.

[0142] More specifically, the first-1 crosslinking agent may include a triacrylate-based compound, a tetraacrylate-based compound, or a combination thereof.

[0143] More specifically, the above-mentioned 1-1 crosslinking agent may include a triacrylate-based compound.

[0144] The above-mentioned 1-1 crosslinking agent may include a monomeric compound. The monomeric crosslinking agent may mean that the remaining moiety, excluding the crosslinking functional group, is of monomer origin.

[0145] The above 1-1 crosslinking agent is 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, ditrimethylolpropane tetra(meth)acrylate, It may include 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 a combination thereof.

[0146] Specifically, the 1-1 crosslinking agent comprises trimethylolethane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, erythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol pentaacrylate, ethoxylated dipentaerythritol pentaacrylate, sorbitol pentaacrylate, It may include dipentaerythritol hexaacrylate, ethoxylated dipentaerythritol hexaacrylate, sorbitol hexaacrylate, or a combination thereof.

[0147] More specifically, the 1-1 crosslinking agent may include trimethylolethane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, propoxylated pentaerythritol tetraacrylate, erythritol tetraacrylate, ditrimethylolpropane tetraacrylate, or a combination thereof.

[0148] More specifically, the 1-1 crosslinking agent may include trimethylolethane triacrylate, trimethylolpropane triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, glycerol triacrylate, ethoxylated glycerol triacrylate, propoxylated glycerol triacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, or a combination thereof.

[0149] The number of crosslinkable functional groups of the first-2 crosslinking agent may be less than the number of crosslinkable functional groups of the first-1 crosslinking agent. If the number of crosslinkable functional groups of the first-1 crosslinking agent is 3, the number of crosslinkable functional groups of the first-2 crosslinking agent may be 2. If the number of crosslinkable functional groups of the first-1 crosslinking agent is 4, the number of crosslinkable functional groups of the first-2 crosslinking agent may be 2 or 3. If the number of crosslinkable functional groups of the first-1 crosslinking agent is 5, the number of crosslinkable functional groups of the first-2 crosslinking agent may be 2, 3, or 4. If the number of crosslinkable functional groups of the first-1 crosslinking agent is 6, the number of crosslinkable functional groups of the first-2 crosslinking agent may be 2, 3, 4, or 5.

[0150] Specifically, apart from the number of crosslinkable functional groups of the first-1 crosslinking agent, the number of crosslinkable functional groups of the first-2 crosslinking agent may be 2. When the number of crosslinkable functional groups of the first-2 crosslinking agent is as small as possible, the first-2 crosslinking agent may provide a space for the liquid electrolyte to be impregnated.

[0151] The above crosslinking agent may include a photoreactive functional group, specifically a (meth)acryloyl group, and since the number of functional groups of the first and second crosslinking agents may be 2, the first and second crosslinking agents may include a di(meth)acrylate-based compound.

[0152] In addition, since it is preferable that the photoreactive functional group includes an acryloyl group, the first and second crosslinking agents may include a diacrylate-based compound.

[0153] The above-mentioned first and second crosslinking agents may include polymeric compounds. The above-mentioned polymeric crosslinking agent may mean that the remaining moiety, excluding the crosslinking functional group, is of polymeric origin.

[0154] Preferably, the first-1 crosslinking agent comprises a monomeric compound, and the second-1 crosslinking agent may comprise a polymeric compound. That is, when the crosslinking agent with a greater number of functional groups is monomeric and the crosslinking agent with a smaller number of functional groups is polymeric, superior properties such as the crosslinking rate, crosslinking density, and flexibility of the electrolyte layer can be more appropriately exhibited.

[0155] The above first and second 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 a combination thereof.

[0156] Specifically, the first and second crosslinking agents may include polyethylene glycol diacrylate, poly(ethylene oxide-propylene oxide) diacrylate, polyurethane diacrylate, polycarbonate diacrylate, or a combination thereof.

[0157] More specifically, the first and second crosslinking agents may include polyethylene glycol diacrylate, polyurethane diacrylate, or a combination thereof.

[0158] More specifically, the first and second crosslinking agents may include polyurethane diacrylate.

[0159] When the first and second crosslinking agents include a polymeric compound, the molecular weight of the polymeric compound may also be controlled. The first and second crosslinking agents 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 and second crosslinking agents may include polyurethane diacrylate with a molecular weight in the range of 1400 g / mol to 2100 g / mol.

[0160] The mixing ratio of the above-mentioned 1-1 crosslinking agent and the above-mentioned 1-2 crosslinking agent can also be appropriately adjusted.

[0161] The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) of the first electrolyte layer and the weight of the first-2 crosslinking agent (C1-2) of the first electrolyte layer may be in the range of 1:9 to 9:1.

[0162] Preferably, the ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) of the first electrolyte layer and the weight of the first-2 crosslinking agent (C1-2) of the first electrolyte layer may be 1.5:8.5 or higher, 2:8 or higher, 2.5:7:5 or higher, 3:7 or higher, 3.5:6.5 or higher, 4:6 or higher, or 4.5:5.5 or higher. The ratio (C1-1:C1-2) of the weight of the first-1 crosslinking agent (C1-1) of the first electrolyte layer and the weight of the first-2 crosslinking agent (C1-2) of the first electrolyte layer may be 8.5:1.5 or lower, 8:2 or lower, 7.5:2.5 or lower, 7:3 or lower, 6.5:3.5 or lower, 6:4 or lower, or 5.5:4.5 or lower.

[0163] Meanwhile, the first electrolyte layer may contain a greater weight of the first-1 crosslinking agent than the first-2 crosslinking agent. The molecular weight of a crosslinking agent with fewer crosslinkable functional groups is higher than that of a crosslinking agent with more crosslinkable functional groups. For this reason, the number of crosslinking bonds per unit volume or unit mass of a crosslinking agent with fewer crosslinkable functional groups is lower compared to a crosslinking agent with more crosslinkable functional groups. Therefore, a crosslinking agent with fewer crosslinkable functional groups may be disadvantageous for smooth crosslinking progress. Consequently, it may be more advantageous for the first electrolyte layer to contain the first-1 crosslinking agent in a greater weight than the first-2 crosslinking agent. Furthermore, at this time, the elasticity of the battery, specifically the electrolyte layer, and more specifically the first electrolyte layer, may be increased.

[0164] The weight of the 1-1 crosslinking agent of the first electrolyte layer and the weight of the 1-2 crosslinking agent of the first electrolyte layer can be adjusted to the weight of the 1-1 crosslinking agent of the first electrolyte composition and the weight of the 1-2 crosslinking agent of the first electrolyte composition.

[0165] The first electrolyte layer may further include an initiator. Specifically, the first electrolyte composition may further include a first initiator.

[0166] When a predetermined stimulus is applied, the first initiator can initiate a reaction in which the first binder forms a polymer matrix.

[0167] The first initiator may include a thermal polymerization initiator, a photopolymerization initiator, or a combination thereof. Preferably, the initiator may include a photopolymerization initiator.

[0168] The above photopolymerization initiator may include a short-wavelength photopolymerization initiator, a long-wavelength photopolymerization initiator, or a combination thereof. Preferably, the photopolymerization initiator may include a long-wavelength photopolymerization initiator.

[0169] The above short-wavelength photopolymerization initiator may include IRGACURE 127 (1,1'-(Methylene-di-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone]), IRGACURE 1173 (2-Hydroxy-2-methylpropiophenone, HMPP), DMPA (2,2-dimethoxy-2-phenylacetonephenone), HOMPP (2-hydroxy-2-methylpropipphenone), LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate), or a combination thereof.

[0170] The above long-wavelength photopolymerization initiator may include one or more selected from the group consisting of Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide and Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate. Preferably, the above long-wavelength photopolymerization initiator may include Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L).

[0171] Additionally, the first electrolyte composition may be impregnated into the pores of the substrate layer. Accordingly, at least a portion of the first electrolyte layer containing a cured product of the first electrolyte composition may be impregnated into the pores of the substrate layer.

[0172] The above electrolyte layer may be formed by curing the above electrolyte composition. The above electrolyte layer may include a cured product of the above electrolyte composition. Specifically, the first electrolyte layer may include a cured product of the first electrolyte composition.

[0173] The above curing method may include, for example, thermal curing, photocuring, and thermal-photo dual curing. Preferably, the curing method may be photocuring.

[0174] A cured product of a composition may refer to a composition that has undergone a chemical process in which it hardens or solidifies as the structure of the components contained in the composition changes due to chemical reactions between those components. This curing may differ from drying, which is a physical process in which a portion of the composition dries or hardens as some of the components contained in the composition (e.g., solvents such as water, volatile components) evaporate.

[0175] A UV curing method may be applied to form the first electrolyte layer on the above substrate layer. The UV curing method is a method of forming cross-linked structures between binders, between binders and crosslinking agents, or between crosslinking agents using an external force. According to the UV curing method, the process of the binder forming a polymer matrix, the process of the binder and inorganic particles dispersing, and the process of the liquid electrolyte impregnating can proceed in the same step.

[0176] The above UV curing method may include the following steps. The number of each step does not indicate the order of the steps:

[0177] (1) Prepare the above electrolyte composition;

[0178] (2) Applying the electrolyte composition to one or both sides of the substrate layer; and

[0179] (3) Irradiate the above electrolyte composition with UV.

[0180] In the above (1) process, the preparation of the electrolyte composition may include directly manufacturing the electrolyte composition or applying a previously manufactured electrolyte composition.

[0181] Conditions such as the application method and thickness of the above electrolyte composition are not particularly limited.

[0182] The conditions of UV irradiation on the above electrolyte composition are not particularly limited.

[0183] The battery separator of the present invention may further include an additional electrolyte layer in addition to the first electrolyte layer. Specifically, the battery separator may further include a second electrolyte layer.

[0184] The second electrolyte layer may be located on the opposite side of the first electrolyte layer. Specifically, the second electrolyte layer may be located on the other side of the substrate layer. The other side of the substrate layer may face one side of the substrate layer.

[0185] The second electrolyte layer may include the electrolyte composition. The electrolyte composition included in the second electrolyte layer may be the second electrolyte composition.

[0186] The second electrolyte composition may have the same or different composition and / or characteristics as the first electrolyte composition. Accordingly, in the description of the second electrolyte composition and the second electrolyte layer in this document, the description of the first electrolyte composition and the first electrolyte layer may be applied as is.

[0187] Another embodiment of the present invention is a battery.

[0188] The 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 the polarity of the second electrode. If the first electrode is a positive electrode (negative electrode), the second electrode may be a negative electrode (positive electrode).

[0189] The system comprising the separator and electrolyte of the above-mentioned battery may be the battery separator of the present invention. Accordingly, the description regarding the separator and electrolyte in the description of the battery can be entirely replaced by the aforementioned battery separator.

[0190] The positive electrode may be an electrode that undergoes a reduction reaction during discharge. The negative electrode may be an electrode that undergoes an oxidation reaction during discharge.

[0191] The electrode of the above battery may include an electrode active material attached to an electrode current collector. Specifically, the electrode may include an electrode current collector and an electrode active material layer disposed on one or both sides of the electrode current collector and comprising an electrode active material.

[0192] Among the electrode active materials, the positive electrode active material may include a lithium intercalation material. The lithium intercalation material may include a lithium transition metal oxide. 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 a combination thereof. Preferably, the positive electrode active material may include lithium nickel-manganese-cobalt oxide.

[0193] Among the above electrode active materials, the negative electrode active material may include a lithium adsorption material. The lithium adsorption material may include a lithium-based metal including lithium metal and lithium alloy; a carbon-based compound including carbon, petroleum coke, activated carbon, and graphite; or a combination thereof.

[0194] The anode current collector may be a foil of a metal comprising aluminum, nickel, or a combination thereof. Preferably, the anode current collector may be an aluminum foil.

[0195] The above-mentioned negative current collector may be a foil of a metal comprising copper, gold, nickel, or a combination thereof. Preferably, the above-mentioned negative current collector may be a copper foil.

[0196] The battery separator of the present invention may be more suitable when the battery is a lithium metal battery. That is, the negative electrode may include lithium metal. Specifically, the negative electrode may include copper as a negative electrode current collector and lithium metal as a negative electrode active material. In particular, the negative electrode may include lithium metal as a main component (e.g., a content of 90 weight% or more) as the negative electrode active material.

[0197] At this time, the first electrolyte layer may be located adjacent to the anode.

[0198] As described above, the battery separator of the present invention may further include a second electrolyte layer located on the other side of the substrate layer. The second electrolyte layer may include a second electrolyte composition.

[0199] At this time, the first electrolyte layer may be located adjacent to the anode. The second electrolyte layer may be located adjacent to the cathode.

[0200] Accordingly, problems caused by the expansion of the negative electrode during the charging and discharging process of the above lithium metal battery can be reduced, and the performance of the battery can be improved.

[0201] The present invention is described in more detail below through examples and comparative examples. However, the present invention is not limited to the examples.

[0202] Example 1. Battery separator

[0203] (1) Prepare a dispersion by dispersing 10 g of the first inorganic particle in 20 g of water. The first inorganic particle is ALK-L1 (Al2O3; D50: 300 nm; true density: 3.95 g / cm³) of Daehan Ceramics. 3 )am.

[0204] (2) 0.1 g of thickener and 1 g of dispersant are added to the above dispersion and stirred with a homogenizer to prepare a first slurry. The thickener is WEALTHY’s CMC2020 (carboxymethyl cellulose; substitution rate: 1.00; viscosity: 15 mPa.s). The dispersant is Toyochem’s CSB-400 (acrylic copolymer; glass transition temperature: -25 ℃; viscosity: 30 cP; solid content: 40 wt%).

[0205] (3) Prepare a dispersion by dispersing 10 g of the second inorganic particles in 20 g of water. The second inorganic particles are LLZO products of GanfengLithium (angular Li 6.4 La3Zr 1.4 Ta 0.6 O 12 ; D50: 300±30 nm; room temperature ionic conductivity: approximately 1.0 mS / cm).

[0206] (4) Add 0.1 g of a thickener and 1 g of a dispersant to the above dispersion and stir with a homogenizer to prepare a second slurry. The thickener is WEALTHY’s CMC2020 (carboxymethyl cellulose; substitution rate: 1.00; viscosity: 15 mPa.s). The dispersant is Toyochem’s CSB-400 (acrylic copolymer; glass transition temperature: -25 ℃; viscosity: 30 cP; solid content: 40 wt%).

[0207] (5) Prepare a solution by adding 3 g of binder, 3.5 g of 1-1 crosslinking agent, and 3.5 g of 1-2 crosslinking agent to 90 g of liquid electrolyte, and then mix the solution with a homogenizer, and then add 0.02 g of photopolymerization initiator to the solution to prepare a first electrolyte composition. The binder is Arkema's Kynar 2501-20 (PVDF-HFP; weight average molecular weight: 350,000 g / mol; HFP substitution rate: 18.6 wt%). The 1-1 crosslinking agent is Miwon Specialty Chemical's M340 (pentaerythritol triacrylate; PETA). The 1-2 crosslinking agent is Miwon Specialty Chemical's Miramer PU2100 (polyurethane diacrylate, weight average molecular weight: 1400). The above photopolymerization initiator is IGM's Omnirad TPO-L (Ethyl (2,4,6-trimethylbenzoyl) phenyl phosphinate). The above liquid electrolyte is a non-aqueous solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 3:7, in which 1 M concentration of LiTFSI (LiN(CF3SO2)2) is dissolved, and 2% of vinylene carbonate (VC) is added by weight.

[0208] (6) Apply the first slurry above to one side of a substrate layer using a slot die and dry it to produce a structure including a first inorganic layer located on one side of the substrate layer. The substrate layer is Asahi’s ND408 (8 μm thick PE film).

[0209] (7) Apply the second slurry above to the other side of the substrate layer using a slot die and dry to produce a structure including a second inorganic layer located on the other side of the substrate layer.

[0210] (8) Apply the first electrolyte composition above onto the first inorganic layer and cure with UV irradiation to produce a battery separator with a total thickness of 30 μm.

[0211] Example 2. Battery separator

[0212] In the above (8), a battery separator with a total thickness of 50 μm was manufactured by repeating the same process as in Example 1, except that the first electrolyte composition was applied over the first inorganic layer and the second inorganic layer, respectively, and cured by UV irradiation.

[0213] Example 3. Battery separator

[0214] A battery separator with a total thickness of 50 μm was prepared by repeating the same process as in Example 1, except that in (5) above, 5.6 g of the first-1 crosslinking agent and 1.4 g of the first-2 crosslinking agent were added, and in (8) above, the first electrolyte composition was applied over each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0215] Example 4. Battery separator

[0216] A battery separator with a total thickness of 50 μm was prepared by repeating the same process as in Example 1, except that in (5) above, 1.4 g of the first-1 crosslinking agent and 5.6 g of the first-2 crosslinking agent were added, and in (8) above, the first electrolyte composition was applied over each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0217] Example 5. Battery separator

[0218] A battery separator with a total thickness of 50 μm was manufactured by repeating the same process as in Example 1, except that in (5) above, M300 (trimethylolpropane triacrylate) of Miwon Specialty Chemicals was used as the first-1 crosslinking agent, and in (8) above, the first electrolyte composition was applied over each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0219] Example 6. Battery separator

[0220] A battery separator with a total thickness of 50 μm was prepared by repeating the same process as in Example 1, except that in (5) above, M300 (trimethylolpropane triacrylate) of Miwon Specialty Chemicals 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) above, the first electrolyte composition was applied over each of the first inorganic layer and the second inorganic layer and cured by UV irradiation.

[0221] Comparative Example 1. Battery separator

[0222] In (6) and (7) above, a battery separator was manufactured by repeating the same process as in Example 1, except that the second slurry was applied to both sides of the substrate layer with a dual slot die and dried to manufacture a structure including a second inorganic layer on both sides of the substrate layer.

[0223] Comparative Example 2. Battery Separator

[0224] A battery separator with a total thickness of 50 μm was manufactured by repeating the same process as in Example 1, except that in (6) and (7) above, the second slurry was applied to both sides of the substrate layer using a dual slot die and dried to produce a structure including a second inorganic layer on both sides of the substrate layer, and in (8) above, the first electrolyte composition was applied to both sides of the structure and cured by UV irradiation.

[0225] Comparative Example 3. Battery Separator

[0226] In (6) and (7) above, a battery separator was manufactured by repeating the same process as in Example 1, except that the first slurry was applied to both sides of the substrate layer with a dual slot die and dried to manufacture a structure including a first inorganic layer on both sides of the substrate layer.

[0227] Comparative Example 4. Battery Separator

[0228] A battery separator with a total thickness of 50 μm was manufactured by repeating the same process as in Example 1, except that in (6) and (7) above, the first slurry was applied to both sides of the substrate layer using a dual slot die and dried to produce a structure including a first inorganic layer on both sides of the substrate layer, and in (8) above, the first electrolyte composition was applied to both sides of the structure and cured by UV irradiation.

[0229] Comparative Example 5. Battery Separator

[0230] A battery separator with a total thickness of 30 μm was manufactured by repeating the same process as in Example 1, except that in (6) and (7) above, the second slurry was applied to both sides of the substrate layer using a dual slot die and dried to produce a structure including a second inorganic layer on both sides of the substrate layer, and in (8) above, the first electrolyte composition was applied to the other side of the structure and cured by UV irradiation.

[0231] [evaluation]

[0232] Experimental Example 1. Ionic Conductivity

[0233] The ionic conductivity of the battery separator was evaluated according to the following process.

[0234] (1) Fabricating a coin cell in which the battery separator of the example and comparative example is positioned between SUS plates. The coin cell is of the 2016 type, and the area of ​​the battery separator is 2.83 cm² 2 (19pi)

[0235] (2) Calculate the resistance and ionic conductivity of the coin cell by applying electrochemical impedance spectroscopy (EIS) to the electrical resistance measurement and converting using the Nyquist plot method. The electrical resistance measurement is performed under AC voltage conditions of an amplitude of 10 mV and a frequency of 1,000,000 to 1,000 Hz.

[0236] Experimental Example 2. Battery Performance

[0237] The discharge capacity and capacity retention rate of batteries made with the battery separators of the examples and comparative examples were measured by the following process.

[0238] (1) Prepare a slurry in which a mixture of 94 wt% LiNiCoMnO2 (Ni:Co:Mn=8:1:1) as a positive active material, 3 wt% conductive carbon black (Super P; IMERYS Graphite & Carbon) as a conductive material, and 3 wt% polyvinylidene fluoride with a weight-average molecular weight of about 800,000 as a binder is uniformly dispersed in NMP (N-methyl-2-pyrrolidone).

[0239] (2) The above slurry is applied to one side of a 20 μm thick aluminum current collector at a pressure of 4.0 mAh / cm 2 Applying a loading amount, followed by drying and rolling to manufacture an anode plate with a laminated anode active material layer.

[0240] (3) The above positive plate is 1.54 cm 2 Stamping into (14 pi) size.

[0241] (4) Produce a cathode plate with a total thickness of 100 μm by rolling lithium metal (negative active material layer) onto a copper plate with a thickness of 10 μm.

[0242] (5) The above cathode plate is 1.76 cm 2 Stamping to a size of (15 pi).

[0243] (6) The positive active material layer of the positive plate and the negative active material layer of the negative plate are arranged to face each other, and 2.83 cm 2Manufacturing an electrode assembly having a structure in which the battery separator cut to a size of (19 pi) is placed between the positive active material layer and the negative active material layer.

[0244] (7) Complete the battery by housing this electrode assembly in a pouch. Five battery samples were prepared. The performance of the above battery is the arithmetic mean of the five samples.

[0245] Prepare the electrochemical analyzer (Toyo, Toscat-3100).

[0246] (8) Charge the battery using the CC-CV method under conditions of 0.2 C, 4.3 V, cut-off 0.05 C, and discharge the battery under conditions of 0.5 C, 3.0 V, cut-off 0.05 C.

[0247] (9) Measure the initial (1 cycle) charge and discharge capacity.

[0248] (10) Measure the charge and discharge capacity after repeating 50 cycles.

[0249] [Results and Discussion]

[0250] Table 1 below shows the test results of the examples and comparative examples.

[0251] Classification Unit Preliminary Comparative Example 1 2 3 4 5 6 1 2 3 4 5 Resistance Ohm 1.8 8 1.5 6 1.9 3 1.6 1 1.6 8 1.9 1 1.9 2 1.6 5 1.9 5 1.7 8 1.9 8 Ionic Conductivity mS / cm 1.1 1.3 2 1.0 5 1.1 9 1.1 8 1.0 9 1.0 3 1.2 1 1.0 5 1.1 3 1.0 1 Cycle Performance 1st (Charge) mAh 42.8 44.6 43.9 43.8 44.8 43.8 41.3 42.9 42.1 43.5 41.2 1st (Discharge) mAh 42.3 44.1 43.2 4 2.843.842.940.842.142.143.541.250th(Discharge)mAh41.841.140.539.140.940.238.139.238.540.036.4 Retention Rate%98.893.193.891.493.493.794.193.192.792.891.5

Claims

1. Record layer; A first inorganic layer located on one surface of the above-mentioned substrate layer and comprising a first inorganic particle; A second inorganic layer located on the other side of the above-mentioned substrate layer and comprising a second inorganic particle; and A first electrolyte layer located on one surface of the first inorganic layer and comprising a first electrolyte composition; Includes, The first inorganic particle above includes flame-retardant inorganic particles, and The above second inorganic particle is a battery separator comprising a lithium ion-transmitting inorganic particle.

2. In Paragraph 1, The above-mentioned first inorganic particle comprises a battery separator comprising SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, Zn2SnO4, ZnSnO3, ZnSn(OH)6, ZrO2, Y2O3, Al2O3, AlOOH, Al(OH)3, TiO2, or a combination thereof.

3. In Paragraph 1, A battery separator in which the D50 (nm) of the first inorganic particle and the D50 (nm) of the second inorganic particle are each independently within the range of 100 to 1000.

4. In Paragraph 1, True density (g / cm²) of the first inorganic particle above 3 ) is the true density (g / cm²) of the second inorganic particle mentioned above. 3 Battery separator smaller than ) 5. In Paragraph 1, The above second inorganic particle is 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 A battery separator comprising (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2), or a combination thereof.

6. In Paragraph 1, The above second inorganic particle is a battery separator comprising a garnet-type crystal structure.

7. In Paragraph 1, The above second inorganic particle is Li 6+x La3Zr 2-y M y O 12-z A battery separator comprising (0≤x≤1, 0≤y≤0.5, 0≤z≤0.2).

8. In Paragraph 1, The above substrate layer is a battery separator comprising a polyolefin-based film.

9. In Paragraph 1, The above first electrolyte composition is a battery separator comprising a first binder, a first liquid electrolyte, and a first crosslinking agent.

10. In Paragraph 9, The above-mentioned first binder is a battery separator comprising a first unit of vinylidene fluoride and a second unit of a fluorine-containing alkyl vinyl compound.

11. In Paragraph 9, The weight-average molecular weight (g / mol) of the above binder is in the range of 150,000 to 600,000, and A battery separator in which the second unit content (weight%) of the above binder is within the range of 10 to 25.

12. In Paragraph 9, The above first liquid electrolyte is a battery separator comprising a non-aqueous solvent, a lithium salt, and an additive.

13. In Paragraph 12, The above-mentioned non-aqueous solvent is a battery separator containing a carbonate-based compound.

14. In Paragraph 13, The above first electrolyte layer is a battery separator containing a linear carbonate compound in a larger volume than a cyclic carbonate compound.

15. In Paragraph 14, The above linear carbonate-based compound is a battery separator comprising dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylmethyl carbonate, or a combination thereof.

16. In Paragraph 14, The above linear carbonate-based compound is a battery separator that is liquid at room temperature.

17. In Paragraph 14, The above-mentioned cyclic carbonate compound is a battery separator comprising vinylethylene carbonate, vinylene carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, propylene carbonate, butylene carbonate, or a combination thereof.

18. In Paragraph 14, The above-mentioned cyclic carbonate-based compound is a battery separator that is solid at room temperature.

19. In Paragraph 14, A battery separator in which the volume (volume%) of the linear carbonate-based compound of the first electrolyte layer is within the range of 55 to 95.

20. In Paragraph 9, The above-mentioned first crosslinking agent comprises a first-1 crosslinking agent and a first-2 crosslinking agent having different numbers of crosslinkable functional groups, and A battery separator having more crosslinkable functional groups than the number of crosslinkable functional groups of the first-1 crosslinking agent.

21. In Paragraph 20, A battery separator having three or more crosslinkable functional groups of the above-mentioned 1-1 crosslinking agent.

22. In Article 20, The above-mentioned 1-1 crosslinking agent comprises a tri(meth)acrylate compound, a tetra(meth)acrylate compound, a penta(meth)acrylate compound, a hexa(meth)acrylate compound, or a combination thereof, for a battery separator.

23. In Paragraph 20, The above-mentioned 1-1 crosslinking agent is a battery separator comprising a monomeric compound.

24. In Paragraph 20, The above 1-1 crosslinking agent is 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, ditrimethylolpropane tetra(meth)acrylate, A battery separator comprising 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 a combination thereof.

25. In Paragraph 20, A battery separator having 2 functional groups of the above 1st and 2nd crosslinking agents.

26. In Paragraph 20, The above-mentioned first and second crosslinking agents are battery separators comprising di(meth)acrylate-based compounds.

27. In Paragraph 20, The above first and second crosslinking agents are battery separators comprising polymeric compounds.

28. In Paragraph 20, The above-mentioned first and second crosslinking agents comprise polyethylene glycol di(meth)acrylate, poly(ethylene oxide-propylene oxide) di(meth)acrylate, polyurethane di(meth)acrylate, polycarbonate di(meth)acrylate, or a combination thereof, for a battery separator.

29. In Paragraph 20, A battery separator in which the ratio (C1-1:C1-2) of the weight of the 1-1 crosslinking agent (C1-1) of the first electrolyte layer and the weight of the 1-2 crosslinking agent (C1-2) of the first electrolyte layer is within the range of 1:9 to 9:

1.

30. In Paragraph 1, A battery separator further comprising a second electrolyte layer located on the other side of the above-mentioned substrate layer and comprising a second electrolyte composition.

31. A positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, and The above separator comprises: a substrate layer; a first inorganic layer located on one side of the substrate layer and comprising a first inorganic particle; a second inorganic layer located on the other side of the substrate layer and comprising a second inorganic particle; and a first electrolyte layer located on one side of the first inorganic layer and comprising a first electrolyte composition. The first inorganic particle above includes flame-retardant inorganic particles, and The above second inorganic particle is a battery comprising lithium ion-transmitting inorganic particles.

32. In Paragraph 31, The above cathode includes lithium metal, and The first electrolyte layer is a battery located adjacent to the positive electrode.

33. In Paragraph 31, The above separator is located on the other side of the substrate layer and further comprises a second electrolyte layer comprising a second electrolyte composition, and The above cathode includes lithium metal, and The first electrolyte layer is located adjacent to the anode, and The above second electrolyte layer is a battery located adjacent to the above negative electrode.