Electrode-integrated separator for lithium ion secondary battery and method for manufacturing same

Abstract

The present disclosure relates to an electrode-integrated separator for a lithium secondary battery and a method for manufacturing the same. According to the present disclosure, an electrode-integrated separator for a lithium secondary battery, which can exhibit excellent insulation characteristics while minimizing the occurrence of defects, and a method for manufacturing the same, are provided.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0109885 filed in the Korean Intellectual Property Office on August 22, 2023, Korean Patent Application No. 10-2023-0109887 filed in the Korean Intellectual Property Office on August 22, 2023, and Korean Patent Application No. 10-2024-0110508 filed in the Korean Intellectual Property Office on August 19, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0003] The present disclosure relates to an electrode-integrated separator for a lithium secondary battery and a method for manufacturing the same. Background Art

[0004] As the trend is toward increasing the functions of mobile phones, laptops, tablet computers, mobile batteries, electric vehicles, personal mobile devices, etc., the demand for secondary batteries used as their driving power sources is steadily increasing. In particular, the most frequently used at present is a lithium secondary battery with a high operating voltage and a high energy density per unit weight.

[0005] A lithium secondary battery generally has a structure in which an electrode assembly having a positive electrode / separator / negative electrode structure that can be charged and discharged is installed in a battery box. Each of the positive electrode and the negative electrode is manufactured by applying a slurry containing an electrode active material, etc. to one surface or both surfaces of a metal current collector, drying the slurry, and rolling the metal current collector to which the dried slurry is applied.

[0006] Separators are one of the most important factors affecting the life of secondary batteries. Separators need to exhibit ion permeability and mechanical strength so that the electrolyte solution can pass through the separator smoothly. As the application of high-energy lithium secondary batteries expands, the safety of separators at high temperatures is also required.

[0007] Conventionally, a separator including a substrate and an inorganic coating has a problem that the adhesion between the separator and the electrode is insufficient due to its material properties, whereby the separator and the electrode are partially separated from each other or wrinkles are formed at the interface between the separator and the electrode. Polyolefins generally used as substrates have problems in thermal stability, such as melting at high temperatures.

[0008] In order to solve these problems, a method of constructing a separator by using only an inorganic coating film without a substrate has been proposed. However, such a separator still does not have sufficient adhesion to the electrode and has significantly low insulation properties, so that when applied to an electrochemical device, the separator is prone to internal short circuits. Such a separator is easily torn due to its low tension and low elongation. Therefore, there is a fatal disadvantage of microscale short circuits occurring in electrode assemblies. Summary of the invention

[0009] Technical issues

[0010] An object of the present disclosure is to provide an electrode-integrated separator for a lithium secondary battery that can exhibit excellent insulation characteristics while minimizing the occurrence of defects.

[0011] An object of the present disclosure is to provide a method for manufacturing an electrode-integrated separator for a lithium secondary battery.

[0012] Technical Solution

[0013] According to one embodiment of the present disclosure,

[0014] Provided is an electrode-integrated separator for a lithium secondary battery, comprising:

[0015] A porous layer stacked on an electrode substrate,

[0016] wherein the porous layer comprises a polymer binder and inorganic fine particles dispersed in the polymer binder, and

[0017] The inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition.

[0018] According to another embodiment of the present disclosure,

[0019] A method for manufacturing an electrode-integrated separator for a lithium secondary battery is provided, the method comprising:

[0020] applying a slurry containing a polymer binder, inorganic fine particles and a solvent on an electrode substrate to form a porous layer,

[0021] The inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition.

[0022] According to still another embodiment of the present disclosure, a lithium secondary battery including the electrode-integrated separator for the lithium secondary battery is provided.

[0023] Now, an electrode-integrated separator for a lithium secondary battery and a method for manufacturing the same according to a specific embodiment of the present disclosure will be described in more detail.

[0024] The terms or words used in this specification and claims should not be construed as limited to common terms or dictionary terms, but should be interpreted with meanings and concepts consistent with the technical ideas of the present disclosure based on the principle that the inventor can appropriately define the concepts of the terms to appropriately describe his own invention in the best manner.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention belongs. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the invention.

[0026] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0027] It should be understood that the terms "comprising", "including", "having" and the like are used herein to specify the presence of stated features, regions, integers, steps, actions, elements and / or components, but do not exclude the presence or addition of other features, regions, integers, steps, actions, elements, components and / or groups.

[0028] Although the present invention can be modified in various ways and adopt various alternative forms, its specific embodiment is described and described in detail below. However, it should be understood that it is not intended to limit the present invention to the specific form disclosed, but on the contrary, the present invention covers all modifications, equivalents and alternatives that fall within the spirit and scope of the present invention.

[0029] When describing a positional relationship, for example, when the positional relationship is described as "on", "above", "below", and "immediately adjacent to", unless "just" or "directly" is used, one or more other parts may be arranged between the two parts.

[0030] When describing a time relationship, for example, when a time sequence is described as "after," "subsequently," "next," and "before," discontinuous cases may be included unless "just" or "directly" is used.

[0031] As used herein, the term “at least one” should be understood to include any and all combinations of one or more of the associated listed items.

[0032] As used herein, the term "green density" means the density (g / cm3 ).

[0033] As used herein, terms including ordinal numbers such as "first", "second", etc. are only used for the purpose of distinguishing one component from another component and are not limited by the ordinal number. For example, without departing from the scope of the present disclosure, the first component may be referred to as the second component, or similarly, the second component may be referred to as the first component.

[0034] As used herein, "one surface of the porous layer facing the electrode substrate" means a surface on the side opposite to one surface of the porous layer contacting the electrode substrate. That is, the porous layer has one surface contacting the electrode substrate and another surface facing the electrode substrate.

[0035] According to one embodiment of the present disclosure,

[0036] Provided is an electrode-integrated separator for a lithium secondary battery, comprising:

[0037] A porous layer stacked on an electrode substrate,

[0038] wherein the porous layer comprises a polymer binder and inorganic fine particles dispersed in the polymer binder, and

[0039] The inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition.

[0040] The continuous research results of the present inventors have shown that an electrode-integrated separator for a lithium secondary battery satisfying the above characteristics can exhibit excellent insulation characteristics while minimizing the occurrence of defects.

[0041] In particular, since the porous layer comprises two or more types of inorganic fine particles with different green density, the porous layer can be given a dense pore structure and a high pore tortuosity. Such a porous layer can show low resistance and high ion conductivity while minimizing the occurrence of defects. In addition, the porous layer can also form a uniform potential in the integrated separator for lithium secondary battery electrodes, thereby being able to show excellent insulation properties.

[0042] An electrode-integrated separator for a lithium secondary battery includes a porous layer stacked on an electrode substrate.

[0043] The electrode substrate may be an electrode substrate for a negative electrode or a positive electrode.

[0044] According to one embodiment, the electrode substrate includes an electrode active material layer stacked on an electrode current collector layer, and the porous layer is stacked on the electrode active material layer.

[0045] Electrode current collectors known in the art to which the present disclosure belongs that have conductivity and do not cause any chemical changes in lithium ion secondary batteries can be applied to the electrode current collector layer. In one example, the electrode current collectors that can be used include stainless steel; aluminum; nickel; titanium; fired carbon; or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, etc.

[0046] Preferably, the thickness of the electrode current collector may be 3 μm to 500 μm. The electrode current collector may form fine protrusions and depressions on its surface to enhance adhesion to the electrode material. The electrode current collector may be used in various forms, such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabric structures.

[0047] The electrode active material layer includes an electrode material composition, which is a mixture of an electrode active material, a conductive material, and a binder.

[0048] Conductive materials can be used to impart electronic conductivity to the electrodes.

[0049] The conductive material can be used without particular limitation, as long as it has electronic conductivity without causing any chemical changes in the lithium ion secondary battery. As a non-limiting example, the conductive material may include carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; graphite such as natural graphite and artificial graphite; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives. As the conductive material, any single one of the above examples or a mixture of two or more thereof may be used.

[0050] The content of the conductive material can be adjusted within a range that does not cause a decrease in the capacity of the battery while exhibiting an appropriate level of conductivity. Preferably, the content of the conductive material can be 1 wt % to 10 wt %, or 1 wt % to 5 wt %, based on the total weight of the electrode material composition.

[0051] The binder is used to properly attach the electrode material composition to the electrode current collector.

[0052] As non-limiting examples, the binder may include polyvinyl alcohol, polyacrylate, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon resin, etc. As the binder, one of the above examples or a mixture of two or more thereof may be used.

[0053] The content of the binder can be adjusted within a range that does not cause a decrease in the capacity of the battery while exhibiting an appropriate level of binding properties. Preferably, the content of the binder can be 1 wt % to 10 wt %, or 1 wt % to 5 wt %, based on the total weight of the electrode material composition.

[0054] When the electrode substrate is a positive electrode, the positive electrode active material may be used without particular limitation as long as it is a material capable of reversibly intercalating / deintercalating lithium ions.

[0055] In one example, the positive electrode active material may be a composite oxide or phosphate including cobalt, manganese, nickel, iron, or a combination of these metals and lithium.

[0056] In another example, the positive electrode active material may be a compound represented by any one of the following chemical formulas: Li a A 1-b R b D 2 (0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b R b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiE 2-b R b O 4-c D c (0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b R c D d (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d≤2);Li a Ni 1-b-c Co b R c O 2-d Z d (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d<2);Li a Ni 1-b-c Co b R c O 2-d Z 2 (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d<2);Li a Ni 1-b- c Mn b R c Dd (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d≤2);Li a Nor 1-b-c Mn b R c O 2-d Z d (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d<2);Li a Nor 1-b-c Mn b R c O 2-d Z 2 (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.05,0 <d<2);Li a Nor b E c G d O 2 (0.90≤a≤1.8,0≤b≤0.9,0≤c≤0.5,0.001≤d≤0.1);Li a Nor b Co c Mn d G e O 2 (0.90≤a≤1.8,0≤b≤0.9,0≤c≤0.5,0≤d≤0.5,0.001≤e≤0.1);Li a NiG b O 2 (0.90≤a≤1.8,0.001≤b≤0.1);Li a CoG b O 2 (0.90≤a≤1.8,0.001≤b≤0.1);Li a MnG b O 2 (0.90≤a≤1.8,0.001≤b≤0.1);Li a Mn 2 G b O 4 (0.90≤a≤1.8,0.001≤b≤0.1);QO 2 ;QS 2 ;LiQS 2 ;V 2 O 5 ;LiV 2 O 5 ;LiTO 2 ;LiLevel 4 ;The (3-f) J2 (PO 4 ) 3 (0≤f≤2);Li (3-f) Fe 2 (PO 4 ) 3 (0≤f≤2); and LiFePO 4 .

[0057] In the above chemical formula, A is Ni, Co, Mn or a combination thereof; R is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element or a combination thereof; D is O, F, S, P or a combination thereof; E is Co, Mn or a combination thereof; Z is F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; Q is Ti, Mo, Mn or a combination thereof; T is Cr, V, Fe, Sc, Y or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu or a combination thereof.

[0058] Those having a coating on the surface of the positive electrode active material can be used, or a mixture of the positive electrode active material and the positive electrode active material having a coating can be used. As the coating element contained in the coating, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr or a mixture thereof can be used.

[0059] According to one embodiment, based on the gross weight of the electrode material composition, the positive electrode active material may be included in an amount of 80 wt % to 95 wt %. Preferably, based on the gross weight of the electrode material composition, the content of the positive electrode active material may be 82 wt % to 95 wt %, or 82 wt % to 93 wt %, or 85 wt % to 93 wt %, or 85 wt % to 90 wt %.

[0060] When the electrode substrate is a negative electrode, the negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping lithium, and a transition metal oxide.

[0061] As a material capable of reversibly embedding and de-embedding lithium ions, crystalline carbon, amorphous carbon, or a mixture thereof as a carbonaceous material can be exemplified. Specifically, the carbonaceous material can be natural graphite, artificial graphite, crystalline graphite (Kishgraphite), pyrolytic carbon, mesophase pitch, carbon fiber based on mesophase pitch, mesophase carbon microspheres, coke derived from petroleum or coal tar pitch, soft carbon, hard carbon, etc.

[0062] The lithium metal alloy may include an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, Sn, Bi, Ga, and Cd.

[0063] Materials capable of doping and de-doping lithium may include Si, Si-C composite materials, SiO x (where 0 < x < 2), Si-Q alloys (where Q is an element selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, but not Si), Sn, SnO 2 , Sn-R (where R is an element selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, but not Sn), etc. In addition, as materials capable of doping and de-doping lithium, at least one of the above examples may be mixed with SiO 2 and then used. Q and R may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, etc.

[0064] In addition, transition metal oxides may include vanadium oxides, lithium vanadium oxides, lithium titanium oxides, etc.

[0065] Preferably, the negative electrode active material may include one or more compounds selected from carbonaceous materials and silicon compounds. Here, as previously exemplified, the carbonaceous material is a material containing at least one of the following: natural graphite, artificial graphite, crystalline graphite, pyrolytic carbon, mesophase pitch, mesophase pitch-based carbon fiber, mesophase carbon microspheres, coke derived from petroleum or coal tar pitch, soft carbon, and hard carbon. In addition, the silicon compound may be the previously exemplified Si-containing compound, i.e., Si, Si-C composite materials, SiO x (where 0 < x < 2), Si-Q alloys, their mixtures, or mixtures of at least one of them with SiO 2 .

[0066] According to one embodiment, based on the total weight of the electrode material composition, the negative electrode active material may be included in an amount of 85 wt % to 98 wt %. Preferably, based on the total weight of the negative electrode material composition, the content of the negative electrode active material may be 85 wt % to 97 wt %, or 87 wt % to 97 wt %, or 87 wt % to 95 wt %, or 90 wt % to 95 wt %.

[0067] According to one embodiment, the thickness of the electrode active material layer is preferably adjusted within the range of 5 μm to 500 μm, or 5 μm to 450 μm, or 10 μm to 450 μm to achieve appropriate performance.

[0068] Meanwhile, the electrode integrated separator for a lithium secondary battery includes a porous layer stacked on an electrode substrate. Preferably, the porous layer is stacked on an electrode current collector layer of the electrode substrate.

[0069] According to one embodiment, the porous layer includes a polymer binder and inorganic fine particles dispersed in the polymer binder.

[0070] The polymer binder can gel when impregnated with a liquid electrolyte and exhibits a high degree of swelling. The electrolyte injected after assembling the lithium secondary battery penetrates into the polymer binder, and the polymer binder containing the adsorbed electrolyte has electrolyte ion conductivity. Therefore, it is preferred to have a solubility index of 15 MPa. 1 / 2 Up to 45MPa 1 / 2 The polymer is applied as a polymer binder.

[0071] As an example, the polymer binder can be at least one compound selected from the following: polyvinylidene fluoride, poly(vinylidene fluoride-co-trichloroethylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), poly(vinylidene fluoride-co-hexafluoropropylene), spandex, butyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone and polyvinyl acetate.

[0072] As another example, the binder may also include at least one compound selected from the following: polyimide, polyetherimide, ethylene vinyl acetate copolymer, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethylated polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, acrylonitrile-styrene-butadiene copolymer, ethylene-propylene-diene terpolymer, sulfonated ethylene-propylene-diene terpolymer, styrene-butadiene rubber and fluororubber, as well as the above-mentioned exemplary compounds.

[0073] The inorganic fine particles form micropores through empty spaces between the particles, maintain their physical shape at high temperatures, and are electrochemically stable.

[0074] According to one embodiment, the inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure conditions. Alternatively, the inorganic fine particles may be composed of two types of inorganic fine particles having different green densities measured under the same pressure conditions.

[0075] The green density of the inorganic fine particles is the density of green pellets produced by filling a mold with a specific amount of inorganic particles and applying pressure, and may vary depending on the material of the inorganic fine particles, the shape of the particles, the size of the particles, or the porosity of the particles.

[0076] Since the porous layer comprises two or more types of inorganic fine particles with different green density, the porous layer can be given a dense pore structure and a high pore tortuosity. Such a porous layer can show low resistance and high ion conductivity while minimizing the occurrence of defects. In addition, the porous layer can form a uniform potential in the integrated separator for lithium secondary battery electrodes, thereby being able to show excellent insulation properties.

[0077] According to one embodiment, the inorganic fine particles may include a 3 Up to 1.5g / cm 3 In 1 ton / cm 2 The green density of the first inorganic fine particle measured under pressure is 0.7 g / cm 3 Up to 1.1g / cm 3 In 1 ton / cm 2 The green density of the second inorganic fine particles is measured under a pressure of 100 Å.

[0078] Here, the size of the mold used to form the first inorganic fine particles and the second inorganic fine particles and the amount of each inorganic fine particle are the same. As an example, when 1 g of any inorganic fine particle is filled in a cylindrical mold having a diameter of 16 mm and 1 ton / cm 2 When a pressure of 1000 Nm is applied to produce green pellets, the first inorganic fine particles and the second inorganic fine particles satisfying the above green density range may be preferably applied.

[0079] Specifically, the green density of the first inorganic fine particles may be 1.20 g / cm 3 or greater, or 1.21g / cm 3 or greater, or 1.22g / cm 3 or greater, or 1.23g / cm 3 or greater, or 1.24g / cm 3or greater, or 1.25g / cm 3 or greater, or 1.26g / cm 3 or greater, or 1.27g / cm 3 or greater, or 1.28g / cm 3 or greater, or 1.29g / cm 3 or greater, or 1.30g / cm 3 or greater, or 1.31 g / cm 3 or greater, or 1.32g / cm 3 or greater, or 1.33 g / cm 3 or greater, or 1.34 g / cm 3 or greater, or 1.35g / cm 3 or greater; and 1.50 g / cm 3 or less, or 1.49g / cm 3 or less, or 1.48g / cm 3 or less, or 1.47g / cm 3 or less, or 1.46g / cm 3 In addition, the green density of the second inorganic fine particles may be 0.70 g / cm 3 or greater, or 0.71 g / cm 3 or greater, or 0.72g / cm 3 or greater, or 0.73g / cm 3 or greater, or 0.74g / cm 3 or greater, or 0.75g / cm 3 or greater, or 0.76g / cm 3 or greater, or 0.77g / cm 3 or greater, or 0.78g / cm 3 or greater, or 0.79 g / cm 3 or greater, or 0.80g / cm 3 or greater; and 1.10 g / cm 3 or less, or 1.09g / cm 3 or less, or 1.08g / cm 3 or less, or 1.07g / cm 3 or less, or 1.06g / cm 3 or less, or 1.05g / cm 3 or less, or 1.04g / cm 3 or less, or 1.03g / cm 3 or less, or 1.02g / cm 3or less, or 1.01g / cm 3 or less, or 1.00g / cm 3 or smaller.

[0080] Preferably, the green density of the first inorganic fine particles may be 1.20 g / cm 3 Up to 1.50g / cm 3 , or 1.21g / cm 3 Up to 1.50g / cm 3 , or 1.22g / cm 3 Up to 1.50g / cm 3 , or 1.23g / cm 3 Up to 1.50g / cm 3 , or 1.24g / cm 3 Up to 1.50g / cm 3 , or 1.25g / cm 3 Up to 1.50g / cm 3 , or 1.25g / cm 3 Up to 1.49g / cm 3 , or 1.25g / cm 3 Up to 1.48g / cm 3 , or 1.26g / cm 3 Up to 1.48g / cm 3 , or 1.27g / cm 3 Up to 1.48g / cm 3 , or 1.28g / cm 3 Up to 1.48g / cm 3 , or 1.29g / cm 3 Up to 1.48g / cm 3 , or 1.30g / cm 3 Up to 1.48g / cm 3 , or 1.30g / cm 3 Up to 1.47g / cm 3 , or 1.30g / cm 3 Up to 1.46g / cm 3 , or 1.31g / cm 3 Up to 1.46g / cm 3 , or 1.32g / cm 3 Up to 1.46g / cm 3 , or 1.33g / cm 3 Up to 1.46g / cm 3 , or 1.34g / cm 3 Up to 1.46g / cm 3 , or 1.35g / cm 3Up to 1.46g / cm 3 In addition, the green density of the second inorganic fine particles may be 0.70 g / cm 3 Up to 1.10g / cm 3 , or 0.71g / cm 3 Up to 1.10g / cm 3 , or 0.72g / cm 3 Up to 1.10g / cm 3 , or 0.73g / cm 3 Up to 1.10g / cm 3 , or 0.74g / cm 3 Up to 1.10g / cm 3 , or 0.75g / cm 3 Up to 1.10g / cm 3 , or 0.75g / cm 3 Up to 1.09g / cm 3 , or 0.75g / cm 3 Up to 1.08g / cm 3 , or 0.75g / cm 3 Up to 1.07g / cm 3 , or 0.75g / cm 3 Up to 1.06g / cm 3 , or 0.75g / cm 3 Up to 1.05g / cm 3 , or 0.76g / cm 3 Up to 1.05g / cm 3 , or 0.77g / cm 3 Up to 1.05g / cm 3 , or 0.78g / cm 3 Up to 1.05g / cm 3 , or 0.79g / cm 3 Up to 1.05g / cm 3 , or 0.80g / cm 3 Up to 1.05g / cm 3 , or 0.80g / cm 3 Up to 1.04g / cm 3 , or 0.80g / cm 3 Up to 1.03g / cm 3 , or 0.80g / cm 3 Up to 1.02g / cm 3 , or 0.80g / cm 3 Up to 1.01g / cm 3 , or 0.80g / cm 3 Up to 1.00g / cm3 .

[0081] In order to impart a dense pore structure and high pore tortuosity to the porous layer, the porous layer preferably contains first inorganic fine particles and second inorganic fine particles satisfying the above green density range.

[0082] However, if the green density of the first inorganic fine particle and the second inorganic fine particle is outside the above range, a dense pore structure may not be formed in the porous layer, and therefore an uneven potential may be formed in the electrode integrated separator for lithium secondary batteries. In addition, if the green density of the first inorganic fine particle and the second inorganic fine particle does not meet the above range, an appropriate level of tortuosity may not be given, and therefore the possibility of defects in the porous layer may increase, and the resistance may increase.

[0083] In one embodiment, the difference in green density between the first inorganic fine particle and the second inorganic fine particle may be 0.20 or more, or 0.21 or more, or 0.22 or more, or 0.23 or more, or 0.24 or more, or 0.25 or more, or 0.26 or more, or 0.27 or more, or 0.28 or more, or 0.29 or more, or 0.30 or more, or 0.31 or more, or 0.32 or more, or 0.33 or more, or 0.34 or more. .34 or greater, or 0.35 or greater; and 0.80 or less, or 0.79 or less, or 0.78 or less, or 0.77 or less, or 0.76 or less, or 0.75 or less, or 0.74 or less, or 0.73 or less, or 0.72 or less, or 0.71 or less, or 0.70 or less, or 0.69 or less, or 0.68 or less, or 0.67 or less, or 0.66 or less, or 0.65 or less.

[0084] In order to give the porous layer a dense pore structure and high pore tortuosity, the difference in density between the first inorganic fine particles and the second inorganic fine particles is preferably 0.20 or greater, or 0.21 or greater, or 0.22 or greater, or 0.23 or greater, or 0.24 or greater, or 0.25 or greater, or 0.26 or greater, or 0.27 or greater, or 0.28 or greater, or 0.29 or greater, or 0.30 or greater, or 0.31 or greater, or 0.32 or greater, or 0.33 or greater, or 0.34 or greater, or 0.35 or greater.

[0085] However, if the difference between the green density of the first fine inorganic particle and the second fine inorganic particle is too large, a dense pore structure may not be formed in the porous layer, and an appropriate level of tortuosity may not be given. Therefore, the difference between the green density of the first fine inorganic particle and the second fine inorganic particle is preferably 0.80 or less, or 0.79 or less, or 0.78 or less, or 0.77 or less, or 0.76 or less, or 0.75 or less, or 0.74 or less, or 0.73 or less, or 0.72 or less, or 0.71 or less, or 0.70 or less, or 0.69 or less, or 0.68 or less, or 0.67 or less, or 0.66 or less, or 0.65 or less.

[0086] Preferably, the difference in green density between the first inorganic fine particles and the second inorganic fine particles may be 0.20 to 0.80, or 0.21 to 0.80, or 0.22 to 0.80, or 0.23 to 0.80, or 0.24 to 0.80, or 0.25 to 0.80, or 0.25 to 0.79, or 0.25 to 0.78, or 0.25 to 0.77, or 0.25 to 0.76, or 0.25 to 0.75, or 0.26 to 0.75, or 0.27 to 0.75, or 0.28 to 0.75, or 0.29 to 0.80. 0.29 to 0.75, or 0.30 to 0.75, or 0.30 to 0.74, or 0.30 to 0.73, or 0.30 to 0.72, or 0.30 to 0.71, or 0.30 to 0.70, or 0.31 to 0.70, or 0.32 to 0.70, or 0.33 to 0.70, or 0.34 to 0.70, or 0.35 to 0.70, or 0.35 to 0.69, or 0.35 to 0.68, or 0.35 to 0.67, or 0.35 to 0.66, or 0.35 to 0.65.

[0087] According to one embodiment, the Brunauer-Emmett-Teller (BET) specific surface area of ​​the first inorganic fine particles by nitrogen adsorption / desorption may be 40 m 2 / g to 80m 2 / g, and the Brunauer-Emmett-Teller (BET) specific surface area of ​​the second inorganic fine particles by nitrogen adsorption / desorption can be 90m 2 / g to 120m 2 / g.

[0088] Specifically, the Brunauer-Emmett-Teller (BET) specific surface area of ​​the first inorganic fine particles by nitrogen adsorption / desorption may be: 40 m 2 / g or more, or 41m 2 / g or more, or 42m 2 / g or more, or 43m 2 / g or more, or 44m 2 / g or more, or 45m 2 / g or greater; and 80m 2 / g or less, or 79m 2 / g or less, or 78m 2 / g or less, or 77m 2 / g or less, or 76m 2 / g or less, or 75m 2 / g or less, or 74m 2 / g or less, or 73m 2 / g or less, or 72m 2 / g or less, or 71m 2 / g or less, or 70m 2 / g or less. In addition, the Brunauer-Emmett-Teller (BET) specific surface area of ​​the second inorganic fine particles by nitrogen adsorption / desorption may be: 90 m 2 / g or greater, or 91m 2 / g or more, or 92m 2 / g or greater, or 93m 2 / g or greater, or 94m 2 / g or greater, or 95m 2 / g or greater; and 120m 2 / g or less, or 119m 2 / g or less, or 118m 2 / g or less.

[0089] In order to impart a dense pore structure and high pore tortuosity to the porous layer, the porous layer preferably contains the first inorganic fine particles and the second inorganic fine particles satisfying the BET specific surface area range. However, if the BET specific surface area of ​​the first inorganic fine particles and the second inorganic fine particles is outside the range, a dense pore structure may not be formed in the porous layer, and an appropriate level of tortuosity may not be imparted.

[0090] Preferably, the BET specific surface area of ​​the first inorganic fine particles by nitrogen adsorption / desorption may be: 40 m 2 / g to 80m 2 / g, or 41m 2 / g to 80m 2 / g, or 42m 2 / g to 80m 2 / g, or 42m2 / g to 79m 2 / g, or 42m 2 / g to 78m 2 / g, or 42m 2 / g to 77m 2 / g, or 42m 2 / g to 76m 2 / g, or 42m 2 / g to 75m 2 / g, or 43m 2 / g to 75m 2 / g, or 44m 2 / g to 75m 2 / g, or 45m 2 / g to 75m 2 / g, or 45m 2 / g to 74m 2 / g, or 45m 2 / g to 73m 2 / g, or 45m 2 / g to 72m 2 / g, or 45m 2 / g to 71m 2 / g, or 45m 2 / g to 70m 2 / g. In addition, the BET specific surface area of ​​the second inorganic fine particles by nitrogen adsorption / desorption can be: 90m 2 / g to 120m 2 / g, or 91m 2 / g to 120m 2 / g, or 92m 2 / g to 120m 2 / g, or 93m 2 / g to 120m 2 / g, or 94m 2 / g to 120m 2 / g, or 95m 2 / g to 120m 2 / g, or 95m 2 / g to 119m 2 / g, or 95m 2 / g to 118m 2 / g.

[0091] The first inorganic fine particles may have a particle size of 1.2 g / cm 3 Up to 1.5g / cm 3 In 1 ton / cm 2 The green density measured under pressure of 40m 2 / g to 80m 2 / g of Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption. In addition, the second inorganic fine particles may have a specific surface area of ​​0.7 g / cm 3 Up to 1.1g / cm 3 In 1 ton / cm 2 The green density measured under pressure of 90m 2 / g to 120m 2 The Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption was 2.17 W / g.

[0092] According to one embodiment, the primary particle diameter of the first inorganic fine particles may be 40nm to 70nm, or 45nm to 70nm, or 45nm to 65nm; and the primary particle diameter of the second inorganic fine particles may be 10nm to 35nm, or 15nm to 35nm, or 20nm to 35nm.

[0093] In addition, the secondary particle diameter of the first inorganic fine particles can be 250nm to 550nm, or 260nm to 550nm, or 260nm to 540nm, or 270nm to 540nm, or 270nm to 530nm; and the secondary particle diameter of the second inorganic fine particles can be 50nm to 230nm, or 60nm to 230nm, or 70nm to 230nm, or 70nm to 220nm, or 70nm to 210nm, or 70nm to 200nm, or 80nm to 200nm, or 90nm to 200nm, or 100nm to 200nm, or 100nm to 190nm, or 100nm to 180nm.

[0094] To ensure appropriate dispersibility and pore size of the inorganic fine particles in the porous layer but prevent the porous layer from being too thick, the porous layer preferably contains first and second inorganic fine particles satisfying the primary and secondary particle diameter ranges.

[0095] The particle diameter of the inorganic fine particles can be determined from a scanning electron microscope image (SEM) or a transmission electron microscope image (TEM) taken of a cross section of the porous layer.

[0096] The first inorganic fine particles may have a particle size of 1.2 g / cm 3 Up to 1.5g / cm 3 In 1 ton / cm 2 The green density measured under a pressure of 250 nm to 550 nm and the secondary particle diameter of the second inorganic fine particles may have a particle size of 0.7 g / cm 3Up to 1.1g / cm 3 In 1 ton / cm 2 The green density and secondary particle diameters ranged from 50 nm to 230 nm were measured under a pressure of 100 Å.

[0097] The first inorganic fine particles may have a particle size of 1.2 g / cm 3 Up to 1.5g / cm 3 In 1 ton / cm 2 The green density measured under pressure of 40m 2 / g to 80m 2 / g Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption, and a secondary particle diameter of 250nm to 550nm. In addition, the second inorganic fine particles may have a specific surface area of ​​0.7g / cm 3 Up to 1.1g / cm 3 In 1 ton / cm 2 The green density measured under pressure of 90m 2 / g to 120m 2 / g, a Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption, and a secondary particle diameter of 50nm to 230nm.

[0098] According to one embodiment, the inorganic fine particles may have a particle shape selected from needle-like particles, angular particles, dendritic particles, fibrous particles, flaky particles, granular particles, irregular particles, nodular particles, and spherical particles.

[0099] Preferably, the first inorganic fine particles and the second inorganic fine particles may have particle shapes different from each other.

[0100] As an example, the first inorganic fine particles may be angular particles, and the second inorganic fine particles may be needle-shaped particles. As another example, the first inorganic fine particles may be irregular particles, and the second inorganic fine particles may be fibrous particles.

[0101] However, since the green density of the inorganic fine particles may vary depending on the material of the inorganic fine particles, the shape of the particles, the size of the particles, or the porosity of the particles, the first inorganic fine particles and the second inorganic fine particles do not necessarily need to have different shapes.

[0102] According to one embodiment, the inorganic fine particles may include first inorganic fine particles and second inorganic fine particles in a weight ratio of 1:1 to 100:1.

[0103] Specifically, the inorganic fine particles may include first and second inorganic fine particles in a weight ratio of 1:1 to 100:1, or 1.5:1 to 100:1, or 1.5:1 to 80:1, or 2:1 to 80:1, or 2:1 to 60:1, or 2:1 to 40:1, or 2:1 to 20:1.

[0104] In order to impart a dense pore structure and high pore tortuosity to the porous layer, the inorganic fine particles preferably include the first inorganic fine particles and the second inorganic fine particles within the weight ratio range.

[0105] However, if the weight ratio of the first inorganic fine particles to the second inorganic fine particles is outside the above range, a dense pore structure may not be formed in the porous layer, and an appropriate level of tortuosity may not be imparted.

[0106] According to one embodiment, it is preferred that the inorganic fine particles do not undergo oxidation and / or reduction reactions within the operating voltage range of the secondary battery (e.g., 0V to 5V based on Li / Li+). The inorganic fine particles preferably have a high electrolyte ion transport capacity. The inorganic fine particles preferably have a density as low as possible so that they can be well dispersed in the polymer binder. In addition, the inorganic fine particles preferably have a high dielectric constant so that they can contribute to improving the degree of dissociation of the electrolyte salt in the electrolyte.

[0107] Preferably, the inorganic fine particles may be one or more selected from inorganic particles having a dielectric constant of 1 or more, inorganic particles having piezoelectricity, and inorganic particles having a lithium ion transporting capability.

[0108] In one embodiment, inorganic particles such as SrTiO 3 SnO 2 、CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 、Al 2 O 3 , Boehmite (AlO(OH)), Al(OH) 3 、TiO 2 And SiC has a dielectric constant of 1 or more, and thus can be preferably used as the inorganic fine particles.

[0109] In another example, the inorganic particles with piezoelectricity are non-conductors at normal pressure, but are materials that exhibit conductivity due to changes in their internal structure when a certain pressure is applied. Piezoelectric inorganic particles have a high dielectric constant characteristic of a dielectric constant of 100 or more. In addition, when the piezoelectric inorganic particles are stretched or compressed under a certain range of pressure, they generate electric charges so that one surface is positively (+) charged and the other surface is negatively (-) charged, thereby generating an electric potential difference between the two surfaces. Due to the above characteristics of the piezoelectric inorganic particles, when an internal short circuit occurs in the electrode of the secondary battery due to an external impact, direct contact between the positive electrode and the negative electrode can be prevented, and the voltage is gradually reduced and safety is improved. As piezoelectric inorganic particles, BaTiO 3 、Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT), Pb(Mg 1 / 3 Nb 2 / 3 ) 3 -PbTiO 3 (PMN-PT) and HfO 2 of inorganic particles.

[0110] In another example, inorganic particles having lithium ion transport capability refer to inorganic particles that contain lithium elements but have the function of moving lithium ions without storing lithium. Inorganic particles having lithium ion transport capability can improve the lithium ion conductivity in the battery. Examples of such inorganic particles include Li 3 PO 4 , Li x Ti y (PO 4 ) 3 (0 <x<2,0<y<3)、Li x Al y Ti z (PO 4 ) 3 (0 <x<2,0<y<1,0<z<3)、(LiAlTiP) x O y (0 <x<4,0<y<13)、Li x La y TiO 3 (0 <x<2,0<y<3)、Li x Ge y P z S w (0 <x<4,0<y<1,0<z<1,0<w<5)、Lix N y (0 < x < 4, 0 < y < 2), Li x Si y S z (0 < x < 3, 0 < y < 2, 0 < z < 4) and Li x P y S z (0 < x < 3, 0 < y < 3, 0 < z < 7) inorganic particles

[0111] Preferably, the inorganic fine particles can be one or more selected from the following: SrTiO 3 、SnO 2 、CeO 2 、MgO, NiO, CaO, ZnO, ZrO 2 、Y 2 O 3 、Al 2 O 3 、AlO(OH), Al(OH) 3 、TiO 2 、SiC, BaTiO 3 、Pb(Zr,Ti)O 3 、Pb 1- x La x Zr 1-y Ti y O 3 、Pb(Mg 1 / 3 Nb 2 / 3 )O 3 -PbTiO 3 、HfO 2 、Li 3 PO 4 、Li x Ti y (PO 4 ) 3 (0 < x < 2, 0 < y < 3), Li x Al y Ti z (PO 4 ) 3 (0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP) x O y (0 < x < 4, 0 < y < 13), Li x La y TiO 3 (0 < x < 2, 0 < y < 3), Li x Ge y P z S w(0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), Li x N y (0 < x < 4, 0 < y < 2), Li x Si y S z (0 < x < 3, 0 < y < 2, 0 < z < 4) and Li x P y S z (0 < x < 3, 0 < y < 3, 0 < z < 7).

[0112] According to one embodiment, the inorganic fine particles include first inorganic fine particles and second inorganic fine particles having different green densities measured under the same pressure conditions; and the first inorganic fine particles and the second inorganic fine particles may have different particle shapes from each other and may be composed of the same type of components.

[0113] According to one embodiment, the porous layer may contain 1 wt% to 90 wt% of a polymer binder and 10 wt% to 99 wt% of inorganic fine particles, or 1 wt% to 40 wt% of a polymer binder and 60 wt% to 99 wt% of inorganic fine particles, or 2 wt% to 30 wt% of a polymer binder and 70 wt% to 98 wt% of inorganic fine particles.

[0114] In order to impart appropriate porosity and insulating properties to the porous layer, the inorganic fine particles are preferably included in an amount of 10 wt% or more. However, if the inorganic fine particles are included in an excessive amount, the mechanical properties of the porous layer may deteriorate due to weakened adhesiveness. Therefore, the inorganic fine particles are preferably included in an amount of 99 wt% or less.

[0115] According to one embodiment, in order to exhibit appropriate performance, the thickness of the porous layer is preferably adjusted in the range of 10 μm to 100 μm, or 10 μm to 80 μm, or 10 μm to 50 μm.

[0116] Meanwhile, according to one embodiment, starting from one surface of the porous layer facing the electrode substrate, in a region of 20% of the total thickness of the porous layer, the second inorganic fine particles may occupy a larger volume than the first inorganic fine particles.

[0117] Since the second inorganic fine particles occupy a larger volume than the first inorganic fine particles in a region of 20% of the total thickness of the porous layer from a surface facing the electrode substrate of the porous layer, the porous layer can have a uniform surface. In addition, since the porous layer has a uniform surface, the pore size of the surface may be reduced due to the fine particle effect, thereby being able to exhibit high insulation properties. In addition, during the operation of a lithium secondary battery including the porous layer, a phenomenon in which lithium ions are locally concentrated on the surface of the porous layer and migrate can be prevented.

[0118] As an example, starting from one surface of the porous layer facing the electrode substrate, in a region of 20% of the total thickness of the porous layer, the first inorganic fine particles may occupy 50% or less of the volume of the second inorganic fine particles (based on 100%).

[0119] In order to exhibit the above-mentioned effects, it is preferred that the first inorganic fine particles occupy 50% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less of the volume relative to the volume of the second inorganic fine particles in the region of the porous layer.

[0120] However, if the volume occupied by the first inorganic fine particles in this region is too small, the tortuosity of the pores in this region may not be given an appropriate level. Therefore, in this region of the porous layer, relative to the volume of the second inorganic fine particles (based on 100%), the first inorganic fine particles preferably occupy 1% or more, or 2% or more, or 3% or more, or 4% or more, or 5% or more, or 6% or more, or 7% or more of the volume.

[0121] Specifically, starting from a surface of the porous layer facing the electrode substrate, in a region of 20% of the total thickness of the porous layer, based on 100% volume of the second inorganic fine particles, the first inorganic fine particles may occupy a volume of 50% or less, or 1% to 50%, or 1% to 45%, or 1% to 40%, or 2% to 40%, or 3% to 40%, or 3% to 35%, or 3% to 30%, or 4% to 30%, or 5% to 30%, or 5% to 25%, or 5% to 20%, or 5% to 15%, or 6% to 15%, or 7% to 15%.

[0122] In addition, starting from a surface of the porous layer facing the electrode substrate, in an area of ​​20%, an area of ​​15%, an area of ​​10%, or an area of ​​5% of the total thickness of the porous layer, the first inorganic fine particles may occupy a volume of 50% or less, or 1% to 50%, or 1% to 45%, or 1% to 40%, or 2% to 40%, or 3% to 40%, or 3% to 35%, or 3% to 30%, or 4% to 30%, or 5% to 30%, or 5% to 25%, or 5% to 20%, or 5% to 15%, or 6% to 15%, or 7% to 15%, relative to the volume of the second inorganic fine particles.

[0123] According to one embodiment, the second inorganic fine particles preferably occupy a smaller volume than the first inorganic fine particles in a region from 20% to 70% of the total thickness of the porous layer from one surface of the porous layer facing the electrode substrate.

[0124] When the second inorganic fine particles preferably occupy a larger volume than the first inorganic fine particles in a region from 20% to 70% of the total thickness of the porous layer from one surface of the porous layer facing the electrode substrate, the pore size in the region may decrease, thereby reducing ionic conductivity (i.e., increasing resistance). Therefore, in this region of the porous layer, it is preferred to allow the first inorganic fine particles to occupy a relatively large volume, thereby reducing the resistance of the porous layer.

[0125] Specifically, starting from a surface of the porous layer facing the electrode substrate, in a region from a point of 20% to a point of 70% of the total thickness of the porous layer, the first inorganic fine particles occupy a volume of 120% or more, or 120% to 2000%, or 120% to 1500%, or 130% to 1500%, or 130% to 1000%, or 130% to 500%, or 130% to 250%, relative to the volume of the second inorganic fine particles (based on 100%).

[0126] In addition, starting from a surface of the porous layer facing the electrode substrate, in a region from 5% point to 100% point, or from 10% point to 100% point, or from 15% point to 100% point, or from 20% point to 100% point, or from 20% point to 90% point, or from 20% point to 80% point, or from 20% point to 70% point of the total thickness of the porous layer, the first inorganic fine particles occupy a volume of 120% or more, or 120% to 2000%, or 120% to 1500%, or 130% to 1500%, or 130% to 1000%, or 130% to 500%, or 130% to 250%, relative to the volume of the second inorganic fine particles (based on 100%).

[0127] The volume ratio of the inorganic fine particles can be obtained by analyzing the cross-sectional SEM image of the porous layer. For example, the volume ratio of the inorganic fine particles can be obtained by quantitatively quantifying the contrast difference of each particle based on the cross-sectional SEM image of the porous layer by rule-based computational visual analysis or the like.

[0128] Meanwhile, according to another embodiment of the present disclosure,

[0129] A method for manufacturing an electrode-integrated separator for a lithium secondary battery is provided, the method comprising:

[0130] applying a slurry containing a polymer binder, inorganic fine particles and a solvent on an electrode substrate to form a porous layer,

[0131] The inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition.

[0132] An electrode-integrated separator for a lithium secondary battery can be provided by the production method.

[0133] In the step of forming the porous layer, the polymer binder, the inorganic fine particles and the electrode substrate are replaced with the above-mentioned ones, respectively.

[0134] According to one embodiment, a slurry including a polymer binder, inorganic fine particles, and a solvent may be obtained by first preparing a dispersion in which two or more types of inorganic fine particles having different green densities are dispersed in a solvent, and then mixing a polymer binder into the dispersion.

[0135] According to one embodiment, the solvent contained in the slurry may preferably be a solvent that exhibits a solubility of 1 wt % or more, or 2.5 wt % or more, or 5 wt % or more, or 7.5 wt % or more, or 10 wt % or more in the polymer binder at room temperature (25° C.).

[0136] Preferably, the solvent may be at least one selected from the following: methyl acetate, ethyl acetate, γ-butyrolactone, ε-caprolactone, dibutyl ether, tetrahydrofuran, cyclohexanone, benzene, fluorobenzene, N-methyl-2-pyrrolidone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, dimethylformamide, 1,3-dioxolane and sulfolane.

[0137] According to one embodiment, the solid content of the slurry is preferably 30% to 80% by weight.

[0138] If the solid content of the slurry is too high, it may cause an increase in viscosity, which may prevent the slurry from penetrating into the pore region of the electrode active material layer, thereby reducing the interfacial adhesion between the electrode substrate and the porous layer. However, if the solid content of the slurry is too low, pinholes may occur during the coating of the slurry, and the drying efficiency of the slurry coating may be reduced.

[0139] Specifically, the solid content of the slurry can be 30 wt % or more; and 80 wt % or less, or 70 wt % or less, or 60 wt % or less. Preferably, the solid content of the slurry can be 30 wt % to 80 wt %, or 30 wt % to 70 wt %, or 30 wt % to 60 wt %.

[0140] Preferably, a slurry containing a polymer binder, inorganic fine particles and a solvent is coated on the electrode active material layer.

[0141] As the coating method of the slurry, conventional methods known in the technical field of the present disclosure can be applied. For example, the slurry can be coated by spin coating, dip coating, die coating, roller coating, comma coating, gravure coating, rod coating, curtain coating, screen printing, inkjet printing, blade coating or a combination thereof.

[0142] In the coating step of the slurry, the thickness of the coating layer formed on the electrode substrate may be adjusted in consideration of the composition of the slurry and the thickness of the porous layer to be finally formed.

[0143] According to one embodiment, the step of forming the porous layer may be performed by vaporizing a solvent in the slurry coated on the electrode substrate.

[0144] Preferably, the step of forming the porous layer may be performed at 80 to 130° C. or 80 to 120° C. If the temperature does not satisfy the above range, drying efficiency may decrease or the shape of the electrode substrate or the porous layer may change to cause defects.

[0145] According to one embodiment, the porous layer formed by the method may include 1 wt % to 90 wt % of a polymer binder and 10 wt % to 99 wt % of inorganic fine particles. In order to give the porous layer appropriate porosity and insulating properties, the inorganic fine particles are preferably included in an amount of 10 wt % or more. However, if the inorganic fine particles are included in an excessive amount, the bonding strength may be weakened, thereby the mechanical properties of the porous layer may be reduced. Therefore, it is preferred that the inorganic fine particles are included in an amount of 99 wt % or less.

[0146] According to still another embodiment of the present disclosure, a lithium secondary battery including the above-mentioned electrode-integrated separator for a lithium secondary battery is provided.

[0147] In one example, a lithium ion secondary battery may include an electrode assembly including a counter electrode disposed on a porous layer of the electrode; an electrolyte impregnated in the electrode assembly; and a battery case sealing and storing the electrode assembly and the electrolyte.

[0148] Since the lithium ion secondary battery includes the above-described electrode assembly, it can exhibit excellent durability and stable performance.

[0149] The lithium ion secondary battery may have various shapes, such as a prismatic shape, a cylindrical shape, or a pouch shape.

[0150] Lithium ion secondary batteries can be used as energy sources with improved performance and safety in the fields of portable electronic devices such as mobile phones, notebook computers, tablet computers, mobile batteries, and digital cameras; and in the fields of transportation vehicles such as electric vehicles, electric motorcycles, and personal mobility devices.

[0151] According to one embodiment, the electrolyte can be used without particular limitation, as long as it is known to be suitable for lithium ion secondary batteries in the technical field to which the present invention belongs. For example, the electrolyte can be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, etc.

[0152] Specifically, the electrolyte may include a non-aqueous organic solvent and a lithium salt.

[0153] The nonaqueous organic solvent may be used without particular limitation as long as it can function as a medium through which ions participating in the electrochemical reaction of the battery can move.

[0154] Specifically, the non-aqueous organic solvents include: ester-based solvents, such as methyl acetate, ethyl acetate, γ-butyrolactone and ε-caprolactone; ether-based solvents, such as dibutyl ether and tetrahydrofuran; ketone-based solvents, such as cyclohexanone; aromatic hydrocarbon-based solvents, such as benzene and fluorobenzene; carbonate-based solvents, such as dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC) and propylene carbonate (PC); alcohol-based solvents, such as ethanol and isopropanol; nitriles, such as R-CN (wherein R is a C2 to C20 linear, branched or cyclic hydrocarbon group, which may contain a double bond aromatic ring or an ether bond); amides, such as dimethylformamide; dioxolanes, such as 1,3-dioxolane; cyclopentane sulfone, etc.

[0155] In the above examples, a carbonate-based solvent may be preferably used as the non-aqueous organic solvent.

[0156] In particular, considering the charging and discharging performance of the battery and the compatibility with the above-mentioned positive electrode material, the non-aqueous organic solvent may preferably be a mixture of a cyclic carbonate (e.g., ethylene carbonate and propylene carbonate) with high ionic conductivity and high dielectric constant and a linear carbonate (e.g., ethyl methyl carbonate, dimethyl carbonate and diethyl carbonate) with a low viscosity carbonate. In this case, mixing and using cyclic carbonate and linear carbonate in a volume ratio of 1:1 to 1:9 can be beneficial to achieving the above-mentioned performance.

[0157] In addition, as the non-aqueous organic solvent, a solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 1:2 to 1:10; or a solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) are mixed in a volume ratio of 1 to 3:1 to 9:1 can be preferably used.

[0158] The lithium salt contained in the electrolyte is dissolved in the non-aqueous organic solvent and serves as a lithium ion source in the battery, which enables the basic operation of the lithium ion secondary battery and facilitates the movement of lithium ions between the positive electrode and the negative electrode.

[0159] The lithium salt may include LiPF 6 、LiClO 4 、LiAsF 6 , LiBF 4 、LiSbF 6 、LiAlO 4 、LiAlCl 4 、LiCF 3 SO 3 ,LiC 4 F 9 SO 3 、LiN(C 2 F 5 SO 3 ) 2 、LiN(C 2 F 5 SO 2 ) 2 、LiN(CF 3 SO 2 ) 2 , LiFSI, LiTFSI, LiCl, LiI and LiB(C 2 O 4 ) 2 Specifically, the lithium salt may be LiPF 6 , LiFSI, LiTFSI, and mixtures thereof.

[0160] The lithium salt may be included in the electrolyte at a concentration of 0.1 M to 2.0 M. The inclusion of the lithium salt in the concentration range imparts appropriate conductivity and viscosity to the electrolyte, thereby exhibiting excellent electrolyte performance.

[0161] Optionally, the electrolyte may contain additives for the purpose of improving battery life characteristics, suppressing decrease in capacity in the battery, improving battery discharge capacity, and the like.

[0162] For example, the additive may include a halogenated alkylene carbonate-based compound such as difluoroethylene carbonate; or pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted Oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, aluminum chloride, etc. The additive may be included in an amount of 0.1 wt % to 5 wt % relative to the total weight of the electrolyte.

[0163] Beneficial Effects

[0164] According to the present disclosure, there are provided an electrode-integrated separator for a lithium secondary battery that exhibits excellent insulation characteristics while minimizing the occurrence of defects, and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0165] Figure 1 is a scanning electron microscope (SEM) image of the surface of the porous layer in the electrode-integrated separator for a lithium secondary battery according to Example 2 of the present disclosure.

[0166] Figure 2 is a SEM image of a cross section of a porous layer in an electrode-integrated separator for a lithium secondary battery according to Example 2 of the present disclosure.

[0167] Figure 3 is a SEM image of the surface of the porous layer in the electrode-integrated separator for a lithium secondary battery according to Example 3 of the present disclosure.

[0168] Figure 4 is a SEM image of a cross section of a porous layer in an electrode-integrated separator for a lithium secondary battery according to Example 3 of the present disclosure.

[0169] Figure 5 is a SEM image of the surface of the porous layer in the electrode-integrated separator for a lithium secondary battery according to Example 4 of the present disclosure.

[0170] Figure 6 is a SEM image of a cross section of a porous layer in an electrode-integrated separator for a lithium secondary battery according to Example 4 of the present disclosure.

[0171] Figure 7 is a SEM image of the surface of the porous layer in the electrode-integrated separator for a lithium secondary battery according to Comparative Example 1 of the present disclosure.

[0172] Figure 8 is a SEM image of a cross section of a porous layer in an electrode-integrated separator for a lithium secondary battery according to Comparative Example 1 of the present disclosure. DETAILED DESCRIPTION

[0173] Hereinafter, the action and effect of the present invention will be described in more detail with reference to specific embodiments. However, the following embodiments are provided to help understand the present invention and are not intended to limit the scope of the present invention in any sense. It will be apparent to those skilled in the art that various modifications and variations may be made in this disclosure without departing from the scope or spirit of the present invention.

[0174] Example 1

[0175] An electrode material composition was prepared, the electrode material composition comprising: 95.6 wt % of an active material, the active material consisting of 90 wt % of a graphite active material (which is a mixture of artificial graphite and natural graphite in a ratio of 3:7) and 10 wt % of SiO; 1 wt % of acetylene black as a conductive material; and 1.1 wt % of carboxymethyl cellulose (CMC) and 2.3 wt % of styrene-butadiene rubber (SBR) as a binder. The electrode material composition was applied to one surface of a copper current collector having a thickness of 8 μm using a comma coater. It was dried and rolled at 130° C. to prepare a negative plate having a negative active material layer stacked thereon. The negative active material layer was formed to have a porosity of 24% and a thickness of 44 μm.

[0176] As inorganic fine particles, horn-shaped boehmite (AlO(OH); green density: 1.35 g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 63m 2 / g; primary particle diameter: 50nm; secondary particle diameter: 350nm) and needle-shaped boehmite (AlO(OH); green density: 0.99g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 101m 2 / g; primary particle diameter: 30nm; secondary particle diameter: 155nm).

[0177] A mixture of 9.5 g of horn-shaped boehmite and 0.5 g of needle-shaped boehmite was dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a dispersion. Poly(vinylidene fluoride-co-hexafluoropropylene) as a polymer binder was added to the dispersion and uniformly mixed using a homogenizer to prepare a slurry having a solid content of 40%.

[0178] The slurry was applied onto the negative electrode active material layer using a double slot die, and then the solvent was vaporized at 100° C. to form a porous layer having a thickness of 17 μm. The composition of the porous layer consisted of 90 wt % of inorganic fine particles and 10 wt % of a polymer binder.

[0179] The negative electrode plate on which the porous layer was formed was punched out into a size of 31 mm×43 mm using a die punch to prepare a negative electrode portion integrated separator.

[0180] The positive electrode active material contained 94 wt % of LiNiCoMnO 2 A mixture of (Ni:Co:Mn=8:1:1), 3 wt% of conductive carbon black (Super P; IMERYS Graphite & Carbon) as a conductive material and 3 wt% of polyvinylidene fluoride as a binder was added to NMP and uniformly dispersed to prepare a slurry. The slurry was applied to one surface of an aluminum current collector, dried and rolled to prepare a positive electrode plate with a positive electrode active material layer stacked thereon. The positive electrode plate was punched into a size of 30 mm × 42 mm using a die punch to produce a positive electrode portion.

[0181] The positive electrode active material layer of the positive electrode portion was placed on the porous layer of the negative electrode portion so as to be adjacent to each other to form an assembly in which the electrodes faced each other, which was pressed and laminated at 90° C. to produce an electrode assembly.

[0182] The electrode assembly was housed in a pouch to form a small battery, and an electrolyte was injected into the pouch to manufacture five lithium secondary batteries.

[0183] At this time, 0.5M LiFSI, 0.7M LiPF 6 The electrolyte used was prepared by dissolving 2 wt % of vinylene carbonate (VC) in a non-aqueous organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7.

[0184] Example 2

[0185] A negative electrode portion-integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that a mixture of 9.0 g of horn-like boehmite and 1.0 g of needle-like boehmite was used as the inorganic fine particles.

[0186] Example 3

[0187] A negative electrode portion-integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that a mixture of 8.0 g of horn-like boehmite and 2.0 g of needle-like boehmite was used as the inorganic fine particles.

[0188] Example 4

[0189] A negative electrode portion-integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that a mixture of 7.0 g of horn-like boehmite and 3.0 g of needle-like boehmite was used as the inorganic fine particles.

[0190] Example 5

[0191] A negative electrode portion integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that 9.5 g of horn-shaped boehmite (AlO(OH); green density: 1.46 g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 45m 2 / g; primary particle diameter: 65nm; secondary particle diameter: 500nm) and 0.5g needle-shaped boehmite (AlO(OH); green density: 0.81g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 118m 2 / g; primary particle diameter: 25 nm; secondary particle diameter: 136 nm) instead of a mixture of horn-shaped boehmite and needle-shaped boehmite as the inorganic fine particles.

[0192] Comparative Example 1

[0193] A negative electrode portion integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that only 10.0 g of horn-shaped boehmite (AlO(OH); green density: 1.35 g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 63m 2 / g; primary particle diameter: 50nm; secondary particle diameter: 350nm) instead of a mixture of horn-shaped boehmite and needle-shaped boehmite as the inorganic fine particles.

[0194] Comparative Example 2

[0195] A negative electrode portion integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that only 10.0 g of needle-like boehmite (AlO(OH); green density: 0.99 g / cm 3; BET surface area by nitrogen adsorption / desorption: 101m 2 / g; primary particle diameter: 30 nm; secondary particle diameter: 155 nm) instead of a mixture of horn-shaped boehmite and needle-shaped boehmite as the inorganic fine particles.

[0196] Comparative Example 3

[0197] A negative electrode portion integrated separator and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that only 10.0 g of horn-shaped boehmite (AlO(OH); green density: 1.46 g / cm 3 ; BET surface area by nitrogen adsorption / desorption: 37m 2 / g; primary particle diameter: 65 nm; secondary particle diameter: 500 nm) instead of a mixture of horn-shaped boehmite and needle-shaped boehmite as the inorganic fine particles.

[0198] Experimental Example 1

[0199] The green density of each of the inorganic fine particles used in Examples and Comparative Examples was obtained by the following method.

[0200] A cylindrical mold with a diameter of 16 mm was filled with 1 g of inorganic fine particles and 1 ton / cm 2 The green density (g / cm2) was calculated from the volume measurement of the green pellet and the weight of the green pellet (1 g). 3 ).

[0201] Experimental Example 2

[0202] The Brunauer-Emmett-Teller (BET) specific surface area of ​​the inorganic fine particles used in Examples and Comparative Examples by nitrogen adsorption / desorption was measured using a surface area analyzer (BEL Japan Inc., BELSORP-max). In the measurement of this characteristic, the temperature of the air oven attached to the analyzer was maintained at 40°C.

[0203] Experimental Example 3

[0204] The dielectric breakdown voltage (kV / mil) of the porous layer of the lithium secondary battery (5 samples each) obtained in the embodiment and the comparative example was measured by the following method. The maximum voltage allowed before dielectric breakdown occurred was measured with a voltage growth rate of 100V / second using a Hi-pot meter (Chroma 19055). The maximum voltage measured was divided by the thickness of the porous layer to calculate the maximum voltage allowed per unit thickness, which is shown in Table 1 below.

[0205] Experimental Example 4

[0206] The resistance (ohm) and ionic conductivity (mS / cm) of the porous layer of the lithium secondary battery (5 samples each) obtained in the embodiment and the comparative example were measured by the following method. The resistance of the porous layer was measured by the Nyquist plot method under the AC voltage conditions of an amplitude of 10Mv and a frequency of 104Hz to 105Hz using electrochemical impedance spectroscopy (EIS). The ionic conductivity was calculated by substituting the measured resistance, the thickness and the area of ​​the porous layer, which are shown in Table 1 below.

[0207] Experimental Example 5

[0208] The lithium secondary batteries obtained in Examples and Comparative Examples were cycled at room temperature at a rate of 0.1 C at 2.5 V to 4.2 V. Furthermore, the charge capacity, discharge capacity, and discharge capacity retention during repeated cycles were measured via the capacity retention of the material in 50 cycles.

[0209] [Table 1]

[0210] Dielectric breakdown voltage (kV / mil) Resistance (Ohm) Ionic conductivity (mS / cm) Example 1 1.12 0.85 1.10 Example 2 1.33 0.85 1.09 Example 3 1.53 0.87 1.05 Example 4 1.16 0.99 0.84 Example 5 1.35 0.85 1.10 Comparative Example 1 0.60 0.94 0.69 Comparative Example 2 0.94 1.34 0.56 Comparative Example 3 0.57 0.95 0.73

[0211] [Table 2]

[0212]

[0213] Referring to Tables 1 and 2, it was determined that the porous layer according to the embodiment exhibited appropriate resistance and high ion conductivity. It was also determined that the porous layer according to the embodiment was endowed with high tortuosity due to a small pore size, thereby exhibiting high dielectric breakdown voltage and excellent life characteristics.

[0214] On the other hand, the porous layer according to the comparative example exhibited a poor dielectric breakdown voltage compared with the example, and exhibited high resistance or low ion conductivity.

[0215] Experimental Example 6

[0216] The surfaces and cross sections of the porous layers formed on the negative electrode plates according to Examples 2, 3, and 4 and Comparative Example 1 were observed using a scanning electron microscope, and the results are shown in FIG. Figures 1 to 8 middle.

[0217] Figure 1 is a SEM image of the surface of the porous layer according to Example 2, and Figure 2 is a SEM image of a cross section of the porous layer according to Example 2.

[0218] Figure 3 is a SEM image of the surface of the porous layer according to Example 3, and Figure 4 is a SEM image of a cross section of the porous layer according to Example 3.

[0219] Figure 5 is a SEM image of the surface of the porous layer according to Example 4, and Figure 6 is a SEM image of a cross section of the porous layer according to Example 4.

[0220] Figure 7 is a SEM image of the surface of the porous layer according to Comparative Example 1, and Figure 8 is a SEM image of a cross section of the porous layer according to Comparative Example 1.

[0221] According to the cross-sectional SEM image of the porous layer, the volume ratio of the first inorganic fine particles and the second inorganic fine particles in the porous layer was quantitatively digitized by using the contrast difference between each particle through rule-based computational visual analysis. The volume ratio in the following region A1 and region A2 of the porous layer (the volume of the first inorganic fine particles, based on 100% volume of the second inorganic fine particles) was calculated and shown in Table 3.

[0222] [Table 3]

[0223]

[0224] * Region A1: A region of 20% of the total thickness of the porous layer starting from one surface of the porous layer facing the electrode substrate.

[0225] * Region A2: A region from a point of 20% to a point of 70% of the total thickness of the porous layer, starting from one surface of the porous layer facing the electrode substrate.

[0226] Reference Figures 1 to 4 It can be observed that, in the porous layers according to Example 2 and Example 3, the needle-like boehmite particles (second inorganic fine particles) are distributed on the surface while occupying a larger volume than the angular boehmite particles (first inorganic fine particles).

[0227] Reference Figure 5 and Figure 6 , it can be observed that, in the porous layer according to Example 4, the needle-like boehmite particles are locally aggregated, compared with Example 2 and Example 3, but it can be observed that pores are densely formed as a whole.

[0228] On the other hand, refer to Figure 7 and Figure 8 , it can be observed that the porous layer according to Comparative Example 1 has a larger pore size and is less dense than that of the example.

[0229] While the present disclosure has been particularly shown and described with reference to several embodiments and illustrative drawings, the disclosure is not limited to these embodiments, and it will be apparent to those skilled in the art that numerous modifications and variations are possible without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An electrode integrated separator for a lithium secondary battery, comprising: A porous layer stacked on an electrode substrate, wherein the porous layer comprises a polymer binder and inorganic fine particles dispersed in the polymer binder, and wherein the inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition.

2. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein: The inorganic fine particles include: With 1.2g / cm 3 Up to 1.5g / cm 3 In 1 ton / cm 2 The green density of the first inorganic fine particle is measured under a pressure of With 0.7g / cm 3 Up to 1.1g / cm 3 In 1 ton / cm 2 The green density of the second inorganic fine particles is measured under a pressure of 100 Å.

3. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein: The second inorganic fine particles occupy a larger volume than the first inorganic fine particles in a region of 20% of the total thickness of the porous layer from one surface of the porous layer facing the electrode substrate.

4. The electrode-integrated separator for a lithium secondary battery according to claim 3, wherein: The first inorganic fine particles occupy 50% or less of the volume relative to the volume of the second inorganic fine particles in a region of 20% of the total thickness of the porous layer from one surface of the porous layer facing the electrode substrate.

5. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein: The second inorganic fine particles occupy a smaller volume than the first inorganic fine particles in a region from 20% to 70% of the total thickness of the porous layer, starting from one surface of the porous layer facing the electrode substrate.

6. The electrode-integrated separator for a lithium secondary battery according to claim 5, wherein: Starting from one surface of the porous layer facing the electrode substrate, the first inorganic fine particles occupy 120% or more of the volume relative to the volume of the second inorganic fine particles in a region from 20% to 70% of the total thickness of the porous layer.

7. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein the inorganic fine particles include: With 40m 2 / g to 80m 2 / g of the first inorganic fine particles having a Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption, and With 90m 2 / g to 120m 2 / g of the second inorganic fine particles having a Brunauer-Emmett-Teller (BET) specific surface area by nitrogen adsorption / desorption.

8. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein the inorganic fine particles include: first inorganic fine particles having a secondary particle diameter of 250 nm to 550 nm, and The second inorganic fine particles have a secondary particle diameter of 50 nm to 230 nm. 9 . The electrode-integrated separator for a lithium secondary battery according to claim 2 , wherein the first inorganic fine particles and the second inorganic fine particles have particle shapes different from each other. 10 . The electrode-integrated separator for a lithium secondary battery according to claim 9 , wherein the first inorganic fine particles and the second inorganic fine particles are composed of the same type of component.

11. The electrode-integrated separator for a lithium secondary battery according to claim 9, wherein: The first inorganic fine particles are angular particles, and The second inorganic fine particles are needle-shaped particles. 12 . The electrode-integrated separator for a lithium secondary battery according to claim 2 , wherein the inorganic fine particles include the first inorganic fine particles and the second inorganic fine particles in a weight ratio of 1:1 to 100:

1.

13. The integrated separator for a lithium secondary battery according to claim 1, wherein the inorganic fine particles are at least one selected from the following: SrTiO3; SnO2; CeO2; MgO; NiO; CaO; ZnO; ZrO2; Y2O3; Al2O3; boehmite (AlO(OH)); Al(OH)3; TiO2; SiC; BaTiO3; Pb(Zr,Ti)O3; Pb 1-x La x Zr 1-y Ti y O3; Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3; HfO2; Li3PO4; Li x Ti y (PO4)3(0 < x < 2, 0 < y < 3); Li x Al y Ti z (PO4)3(0 < x < 2, 0 < y < 1, 0 < z < 3); (LiAlTiP) x O y (0 < x < 4, 0 < y < 13); Li x La y TiO3(0 < x < 2, 0 < y < 3); Li x Ge y P z S w (0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5); Li x N y (0 < x < 4, 0 < y < 2); Li x Si y S z (0 < x < 3, 0 < y < 2, 0 < z < 4); and Li x P y S z (0 < x < 3, 0 < y < 3, 0 < z < 7).

14. The electrode integrated separator for a lithium secondary battery according to claim 1, wherein the polymer binder is at least one compound selected from the group consisting of polyvinylidene fluoride, poly(vinylidene fluoride-co-trichloroethylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), poly(vinylidene fluoride-co-hexafluoropropylene), spandex, butyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinyl pyrrolidone and polyvinyl acetate. 15 . The electrode-integrated separator for a lithium secondary battery according to claim 1 , wherein the porous layer comprises 1 to 90 wt % of the polymer binder and 10 to 99 wt % of the inorganic fine particles.

16. The electrode-integrated separator for a lithium secondary battery according to claim 1, wherein: The electrode substrate includes an electrode active material layer stacked on an electrode current collector layer, and The porous layer is stacked on the electrode active material layer.

17. A method for manufacturing the electrode-integrated separator for a lithium secondary battery according to claim 1, the method comprising: applying a slurry containing a polymer binder, inorganic fine particles and a solvent on an electrode substrate to form a porous layer, wherein the inorganic fine particles include two or more types of inorganic fine particles having different green densities measured under the same pressure condition. 18 . The method for manufacturing an electrode-integrated separator for a lithium secondary battery according to claim 17 , wherein the solid content of the slurry is 30 wt % to 80 wt %.

19. The method for manufacturing an electrode integrated separator for a lithium secondary battery according to claim 17, wherein the solvent is at least one selected from the group consisting of methyl acetate, ethyl acetate, γ-butyrolactone, ε-caprolactone, dibutyl ether, tetrahydrofuran, cyclohexanone, benzene, fluorobenzene, N-methyl-2-pyrrolidone, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, dimethylformamide, 1,3-dioxolane and sulfolane. 20 . The method for manufacturing an electrode-integrated separator for a lithium secondary battery according to claim 17 , wherein the forming of the porous layer is performed by vaporizing the solvent in the slurry coated on the electrode substrate at 80° C. to 130° C. 21 . A lithium secondary battery comprising the electrode-integrated separator for a lithium secondary battery according to claim 1 .

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