Self-supporting film laminate for an anode of a lithium secondary battery and method for producing the same

Abstract

A self-standing film laminate for an anode of a lithium secondary battery and a method for producing the same, wherein the self-standing film laminate comprises a first self-standing film comprising a first anode active material, a first conductive material, and a first binder containing a triblock copolymer, and a second self-standing film comprising a second anode active material, a second conductive material, and a second binder containing a fluorine-based resin, wherein the triblock copolymer comprises a soft block derived from aliphatic or cycloaliphatic diene-based monomers and having a rubber phase at room temperature, and a first hard block and a second hard block, each connected to both ends of the soft block by an aromatic ring-containingethylenically unsaturated monomer and which have a glass phase at room temperature, wherein the first binder is in the form of a discontinuous column which provides a connection between any one of a region of the first anode active material or a region of the first conductive material and another of a region of the first anode active material or a region of the first conductive material.

Description

BACKGROUND field

[0001] The present invention relates to a self-standing film laminate for an anode of a lithium secondary battery using a binder comprising a triblock copolymer containing a soft block (e.g., a soft block) and a hard block (e.g., a hard block), and a method for producing the same. background

[0002] Lithium secondary batteries have been widely used in portable electronics since their initial commercial introduction in the 1990s and are of continued interest as the most researched energy storage systems. With characteristics such as high operating voltage, high energy density, low self-discharge, high performance (e.g., high power rate), and long cycle stability, lithium secondary batteries meet the requirements for being suitable as a power source for electric vehicles. However, lithium secondary batteries applied to / in electric vehicles still face three major challenges: safety, operating time, and cost.The problems of safety and service life can be solved by using solid-state batteries, and yet the cost problem contributes to hindering the widespread application of lithium secondary batteries, and therefore, intensive research is being carried out to reduce the cost of lithium secondary batteries.

[0003] Reducing energy consumption during manufacturing or increasing electrode thickness is one of the most effective ways to reduce the manufacturing costs of lithium secondary batteries. Typical electrode manufacturing processes involve casting a current collector with a slurry containing an electrode active material, a polymer binder, and a conductive additive mixed in water or an organic solvent, and then drying and pressing the resulting product to form an electrode. However, the energy required to prepare the slurry and coat the current collector accounts for approximately 50% of the energy consumed during the entire manufacturing process. Therefore, a solvent-free dry electrode manufacturing process has been explored to reduce the manufacturing costs of lithium secondary batteries.

[0004] Although the methods for manufacturing dry electrodes have been extensively researched, the development of dry electrodes with excellent mechanical properties, a not too high elongation rate to facilitate mass production, excellent adhesion of a self-standing film to a current collector, and high flexibility has not yet been achieved, which requires further research and development. BRIEF EXPLANATION OF THE INVENTION

[0005] One aspect of the present invention provides a self-standing film laminate (e.g., a self-standing film sheet, e.g., a self-standing film laminate, e.g., a self-standing coating laminate) for an anode of a lithium secondary battery (e.g., a lithium-containing auxiliary battery) having excellent mechanical properties, satisfactory elongation, excellent adhesion to a current collector, and excellent flexibility, and a method for producing the same.

[0006] In one aspect, a self-standing film laminate is provided which is suitable for an anode of a lithium secondary battery, the self-standing film laminate comprising (i) a first self-standing film comprising a) a first anode active material, b) a first conductive (e.g., conductive) material, and c) a first binder (e.g., a first binder, e.g., a first base material) comprising (e.g., containing) a triblock copolymer (e.g., a three-block copolymer), and (ii) a second self-standing film comprising a) a second anode active material, b) a second conductive material, and c) a second binder comprising a fluorine-based resin, the triblock copolymer comprising a soft (e.g., shape-changing) block,which is derived from (for example from) aliphatic or cycloaliphatic diene-based monomers (for example diene-based monomers) (for example produced, for example obtained, for example derived) and has a rubber phase (for example an elastic phase) at room temperature, and a first hard (for example dimensionally stable, for example solid) block and a second hard block, which are (for example respectively associated) connected to both ends of the soft block, which are derived from an ethylenically unsaturated monomer containing an aromatic ring (for example an aromatic compound, for example an aromatic) and have a glass phase at room temperature, and wherein the first binder comprises any one of i) a region (for example a domain,for example, a region) of the first anode active material or ii) a region of the first conductive material and another (e.g. the other) of) a) a region of the first anode active material or b) a region of the first conductive material.,

[0007] In another aspect, a self-standing film laminate for an anode of a lithium secondary battery is provided, the self-standing film laminate comprising a first self-standing film (e.g., a first self-standing foil, e.g., a first self-standing coating) comprising a first anode active material (e.g., a first anode active material, e.g., a first anode active material), a first conductive material, and a first binder comprising a triblock copolymer, and a second self-standing film comprising a second anode active material, a second conductive material, and a second binder containing a fluorine-based resin.In this case, the triblock copolymer may comprise a soft block derived from aliphatic or cycloaliphatic diene-based monomers and having a rubbery phase at room temperature, and a first hard block and a second hard block connected (e.g., respectively associated) to both ends of the soft block, which are derived from an ethylenically unsaturated monomer containing an aromatic ring and which have a glassy phase at room temperature, wherein the first binder may be in the form of a discontinuous column providing a connection between any one of a region of the first anode active material or a region of the first conductive material and another (e.g., the other) of a region of the first anode active material or (e.g., a further one of) a region of the first conductive material.

[0008] According to another aspect of the present invention, there are provided an anode for a lithium secondary battery comprising the self-standing film laminate for an anode of a lithium secondary battery, a lithium secondary battery comprising the anode for a lithium secondary battery, a method for producing the self-standing film laminate for an anode of a lithium secondary battery, and a method for producing the anode for a lithium secondary battery.

[0009] In aspects, in a self-standing film laminate as disclosed herein, the first self-standing film and the second self-standing film desirably have a thickness ratio of 1:0.01 to 1:0.49.

[0010] In aspects, in a self-standing film laminate as disclosed herein, the film laminate suitably has a three-layer structure in which the first self-standing film is stacked on each of an upper side and a lower side of the second self-standing film (e.g., in which a first self-standing film is disposed on an upper side of the second self-standing film and in which another first self-standing film is disposed on a lower side of the second self-standing film).

[0011] In aspects, in a self-standing film laminate as disclosed herein, the film laminate advantageously comprises a repeated alternating stack structure of the first self-standing film and the second self-standing film.

[0012] In aspects, in a self-standing film laminate as disclosed herein, the region of the first anode active material or the region of the first conductive material and the first binder having the shape of a discontinuous column are suitably bonded to form a three-dimensional network structure.

[0013] In aspects, in a self-standing film laminate as disclosed herein, the first binder desirably has an average width perpendicular to the longitudinal direction of 0.1 µm to 2 µm.

[0014] In a self-standing film laminate as disclosed herein, in aspects, a first glass transition temperature and a second glass transition temperature associated with the first hard block and the second hard block (e.g., corresponding to the first hard block and the second hard block, respectively) are suitably 50°C to 120°C, and in aspects, a third glass transition temperature corresponding to the soft block (e.g., corresponding to the soft block) is suitably -120°C to -50°C.

[0015] In aspects, in a self-standing film laminate as disclosed herein, the soft block is desirably derived from an aliphatic diene-based monomer comprising at least one selected from the group consisting of a butadiene-based monomer, a pentadiene-based monomer, and a hexadiene-based monomer.

[0016] In aspects, in a self-standing film laminate as disclosed herein, the first hard block and the second hard block are each suitably independently derived from one (e.g., different) aromatic ring-containing ethylenically unsaturated monomer(s) comprising at least one (e.g., each comprising at least one) of a styrene-based monomer and an aromatic (meth)acrylic-based monomer.

[0017] In one aspect, a negative electrode of a lithium secondary battery is provided having (e.g., containing) the composition described herein.

[0018] In one aspect, a lithium secondary battery is provided having the negative electrode described herein.

[0019] In one aspect, a vehicle is provided having the lithium secondary battery described herein.

[0020] As used herein, the term "self-supporting" refers to a sheet (e.g., a layer, e.g., a thin film) that can be handled as an independent (e.g., single) sheet without support from a substrate or backing (e.g., a carrier). Thus, the term "self-supporting" can have the same meaning as "self-supporting."

[0021] As used herein, the term "all-solid-state battery" (e.g., "solid-state accumulator," e.g., "all-solid-state battery," e.g., "solid-state battery") includes or refers to a rechargeable battery (including a secondary battery) that includes a solid-state electrolyte, e.g., a gel or a (cured) polymer, which may include an ionomer and other electrolytic components for transferring ions between the battery's electrodes. In certain aspects, a lithium secondary battery referred to herein is an all-solid-state battery.

[0022] As mentioned herein, a rubber phase or state lies above the T g(glass transition temperature) of the material, i.e. where the material may be in a more rubbery state and may be comparatively soft and flexible. Therefore, when it is stated herein that the material forms a rubbery phase at room temperature (e.g., 25 °C), the material may be above its glass transition temperature at room temperature (25 °C) and be in a comparatively rubbery or more flexible state. As mentioned herein, a glassy phase or state is below the T g (glass transition temperature) of the material, and at this temperature, the material may exhibit a stiffer or more glassy configuration. Thus, when it is stated herein that the material forms a glass phase at room temperature (e.g., 25°C), the material may be below its glass transition temperature at room temperature (25°C) and in a comparatively rigid or hardened state.

[0023] As used herein, the term "all-solid-state battery" refers to a rechargeable secondary battery that includes a solid-state electrolyte, such as a gel or a (cured) polymer, which may include an ionomer and other electrolytic components for transferring ions between the battery's electrodes. In certain aspects, a lithium secondary battery referred to herein is an all-solid-state battery.

[0024] The term "self-supporting film, laminate, or sheet" or a similar term used herein means that the film, laminate, or sheet may be in the form of a sheet (e.g., a thin film) and may be handled as an independent sheet without support from a substrate or carrier. Thus, the term "self-supporting" may have the same meaning as "self-supporting."

[0025] The term "block polymer" as used herein includes (for example, includes) a polymer having two or more chemically distinct regions or segments (referred to as "blocks") that are typically linearly linked together, e.g., a polymer having chemically differentiated units that are joined (covalently bonded) end-to-end with respect to polymerized functionality (e.g., end-bonded), rather than in a pendant or grafted form. In one aspect, a block polymer can comprise (i) a first polymer block having at least 5, 10, 20, or 30 first repeating units; and (ii) a second polymer block having at least 5, 10, 20, or 30 second repeating units.

[0026] As used herein, the terms "soft block" and "hard block" mean that the respective polymer units or sections (e.g., parts) differ, e.g., in their structure and one or more properties. In certain aspects, the soft block may have a lower glass transition temperature (e.g., Tg) or melting temperature (e.g., below room temperature) than a hard block (which may have a glass transition temperature or melting temperature that is higher (e.g., above room temperature) than the application temperature of the formed block copolymer material). In certain embodiments, the Tg of hard and soft blocks may differ, e.g., by up to or more than 3°C, 5°C, 10°C, 20°C, or 30°C.

[0027] Further aspects are explained below. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings in which: Fig. 1A and Fig. 1B are SEM images (e.g., scanning electron microscope images, e.g., SEM images, e.g., scanning electron microscope images) of a first self-standing film according to Production Example 1-1, Fig. 1C is a view showing a network structure formed in the self-standing film according to Production Example 1-1, Fig. 2A is an SEM image of a composition (mixed powder) for forming (e.g., molding, e.g., forming) a self-standing film before producing the first self-standing film of Production Example 1-1, Fig.2B is an SEM image of SBS powder (e.g., styrene-butadiene-styrene powder, e.g., styrene-butadiene-styrene powder) before manufacturing the Fig. 2A shown mixed powder, Fig. 3A is a picture taken after evaluating a flexibility of a self-standing film laminate of Example 1 according to Experimental Example 3, Fig. 3B is an image taken after evaluating a flexibility of a self-standing film of Comparative Example 1 according to Experimental Example 3, and Fig. 3C is an image taken after evaluating a flexibility of a self-standing film of Reference Example 1 according to Experimental Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0029] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] Hereinafter, a self-standing film laminate for an anode of a lithium secondary battery and a method for producing the same will be described in detail so that the present invention can be easily carried out by a person skilled in the art to which the present invention relates. Self-contained film laminate for an anode of a lithium secondary battery

[0031] A self-standing film laminate for an anode of a lithium secondary battery of the present invention is a laminate comprising a first self-standing film and a second self-standing film. First stand-alone film

[0032] The first self-standing film comprises a first binder, a first anode active material and a first conductive material.

[0033] The first binder may comprise a triblock copolymer. In this case, the triblock copolymer may comprise a soft block derived from aliphatic or cycloaliphatic diene-based monomers and having a rubbery phase at room temperature, and a first hard block and a second hard block connected (e.g., respectively) to both ends of the soft block, which are derived from an ethylenically unsaturated monomer containing an aromatic ring and which have a glassy phase at room temperature. The first binder containing the triblock copolymer may be in the form of a discontinuous column connecting any one of a region of the first anode active material or a region of the first conductive material to another region of the first anode active material or another region of the first conductive material.

[0034] The soft block may comprise (for example include) repeating units derived from aliphatic diene-based monomers and / or cycloaliphatic diene-based monomers having a rubber phase at room temperature, and the soft block may (for example the repeating units may) in particular be derived from aliphatic diene-based monomers comprising at least one selected from the group consisting of a butadiene-based monomer, a pentadiene-based monomer and a hexadiene-based monomer.

[0035] The butadiene-based monomer may comprise at least one selected from the group consisting of 1,2-butadiene, 1,3-butadiene, isoprene and chloroprene.

[0036] The pentadiene-based monomer may comprise at least one selected from the group consisting of 1,2-pentadiene, 1,3-pentadiene, 1,4-pentadiene, 2,3-pentadiene, 2-methyl-1,3-pentadiene, 2-methyl-1,4-pentadiene, 2-methyl-2,3-pentadiene, 2-methyl-2,4-pentadiene, 3-methyl-1,3-pentadiene, 3-methyl-1,4-pentadiene, 4-methyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 2-ethyl-1,4-pentadiene, 2-ethyl-2,4-pentadiene, 3-ethyl-1,3-pentadiene, 3-Ethyl-1,4-pentadiene, 4-Ethyl-1,3-pentadiene, 1-Chloro-1,3-pentadiene, 1-Chloro-2,4-pentadiene, 2-Chloro-1,3-pentadiene, 3-Chloro-1,3-pentadiene, 3-Chloro-1,4-pentadiene and 5-Chloro-1,3-pentadiene (for example, consists of (1,2-pentadiene), (1,3-pentadiene), (1,4-pentadiene), (2,3-pentadiene), (2-Methyl-1,3-pentadiene), (2-Methyl-1,4-pentadiene), (2-Methyl-2,3-pentadiene), (2-Methyl-2,4-pentadiene), (3-methyl-1,3-pentadiene), (3-methyl-1,4-pentadiene), (4-methyl-1,3-pentadiene), (2-ethyl-1,3-pentadiene), (2-ethyl-1,4-pentadiene), (2-ethyl-2,4-pentadiene), (3-ethyl-1,3-pentadiene),(3-Ethyl-1,4-Pentadien), (4-Ethyl-1,3-Pentadien), (1-Chlor-1,3-Pentadien), (1-Chlor-2,4-Pentadien), (2-Chlor-1,3-Pentadien), (3-Chlor-1,3-Pentadien), (3-Chlor-1,4-Pentadien) und (5-Chlor-1,3-Pentadien)).,

[0037] The hexadiene-based monomer may comprise at least one selected from the group consisting of 1,2-hexadiene, 1,3-hexadiene, 1,4-hexadiene, 1,5-hexadiene, 2,3-hexadiene, 2,4-hexadiene, 2,5-hexadiene, 3,5-hexadiene, 2-methyl-1,3-hexadiene, 2-methyl-1,4-hexadiene, 2-methyl-1,5-hexadiene, 2-methyl-2,3-hexadiene, 2-methyl-2,4-hexadiene, 3-methyl-1,2-hexadiene, 3-methyl-1,3-hexadiene, 3-methyl-1,4-hexadiene, 3-methyl-1,5-hexadiene, 3-Methyl-2,4-Hexadiene, 3-Methyl-2,5-Hexadiene, 4-Methyl-1,3-Hexadiene, 4-Methyl-1,4-Hexadiene, 4-Methyl-2,3-Hexadiene, 5-Methyl-1,3-Hexadiene, 5-Methyl-1,4-Hexadiene, 2-Ethyl-1,3-Hexadiene, 2-Ethyl-1,4-Hexadiene, 3-Ethyl-1,2-Hexadiene, 3-Ethyl-1,3-Hexadiene, 3-Ethyl-1,4-Hexadiene and 3-Ethyl-1,5-Hexadiene (for example, consists of consists of (1,2-Hexadiene), (1,3-Hexadiene), (1,4-Hexadiene), (1,5-Hexadiene), (2,3-Hexadiene), (2,4-hexadiene), (2,5-hexadiene), (3,5-hexadiene), (2-methyl-1,3-hexadiene), (2-methyl-1,4-hexadiene), (2-methyl-1,5-hexadiene), (2-methyl-2,3-hexadiene),(2-methyl-2,4-hexadiene), (3-methyl-1,2-hexadiene), (3-methyl-1,3-hexadiene), (3-methyl-1,4-hexadiene), (3-methyl-1,5-hexadiene), (3-methyl-2,4-hexadiene), (3-methyl-2,5-hexadiene), (4-methyl-1,3-hexadiene), (4-methyl-1,4-hexadiene), (4-methyl-2,3-hexadiene), (5-methyl-1,3-hexadiene), (5-methyl-1,4-hexadiene), (2-ethyl-1,3-hexadiene), (2-ethyl-1,4-hexadiene), (3-Ethyl-1,2-Hexadiene), (3-Ethyl-1,3-Hexadiene), (3-ethyl-1,4-hexadiene) and (3-ethyl-1,5-hexadiene)).

[0038] The soft block can serve to impart flexibility to the triblock copolymer and improve extrusion molding properties and wear resistance.

[0039] The first hard block and the second hard block may comprise a repeating unit derived from an ethylenically unsaturated monomer having an aromatic ring and (for example, the first hard block and the second hard block may) have a glass phase at room temperature, specifically, the aromatic ring contained in the ethylenically unsaturated monomer may be a substituted or unsubstituted benzene ring or a substituted or unsubstituted naphthalene ring.

[0040] In addition, the aromatic ring may be connected to a main chain or a side chain (e.g., side chain) of the repeating units of the first hard block and the second hard block, and may preferably be connected to a side chain of the repeating units of the first hard block and the second hard block.

[0041] The first hard block and the second hard block may each be independently derived from an aromatic ring-containing ethylenically unsaturated monomer comprising at least one of a styrene-based monomer and an aromatic (meth)acrylic-based monomer.

[0042] The styrene-based monomer may comprise at least one selected from the group consisting of styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethoxystyrene, t-butoxystyrene, p-acetoxystyrene, p-chlorostyrene, p-bromostyrene, 2,4-dimethylstyrene, 3,5-dimethylstyrene and 2,4,6-trimethylstyrene.

[0043] The (meth)acrylic-based aromatic monomer may comprise at least one selected from the group consisting of benzyl acrylate, benzyl methacrylate, phenoxyacrylate, phenoxymethacrylate, phenyl acrylate, phenyl methacrylate, phenylethyl acrylate and phenylethyl methacrylate.

[0044] The first hard block and the second hard block can be firmly bonded (e.g., bonded) to the first anode active material or the first conductive material through pi-pi interactions resulting from the aromatic ring structure contained in the repeating units. Additionally, the first hard block and the second hard block can impart high strength properties to the triblock copolymer containing the first hard block and the second hard block.

[0045] In one embodiment, the first hard block and the second hard block may be present in an amount of 10 wt% to 60 wt%, preferably 15 wt% to 55 wt%, more preferably 20 wt% to 50 wt%, based on the total amount of the triblock copolymer (for example, the first hard block and the second hard block may account for 10-60%, preferably 15-55%, more preferably 20-50% of the mass of the triblock copolymer, for example, at the start of production, for example, in a finished product). When the amount of the first hard block and the second hard block satisfies the numerical range described above, the bonding strength can be further improved due to strong interactions with the first negatively active material or the first conductive material, and the triblock copolymer can have sufficient flexibility to be endowed with much better molding properties.

[0046] In one embodiment, the first hard block and the second hard block may each have a weight average molecular weight (e.g., a weight average molecular weight) of 9000 g / mol to 20000 g / mol, preferably 9500 g / mol to 20000 g / mol, more preferably 10000 g / mol to 20000 g / mol. When the weight average molecular weight of each of the first hard block and the second hard block satisfies the above-described numerical range, the physical crosslinking force between the first binder and the first anode active material or the first conductive material can be improved to form a more stable three-dimensional network structure, and deformation can be easy when manufacturing electrodes to further improve processability.

[0047] The first anode active material may comprise at least one selected from the group consisting of a carbon-based active material, a silicon-based active material, a metal-based active material capable of being alloyed with lithium, and a lithium-containing active material.

[0048] The carbon-based active material can be, for example, graphite, hard carbon, soft carbon, or graphene. The graphite can be artificial graphite, natural graphite, a mixture of artificial graphite and natural graphite, natural graphite coated with artificial graphite, or a combination thereof.

[0049] The carbon-based active material changes its crystal structure only slightly during the process of intercalation (e.g., insertion) and deintercalation (e.g., removal) of lithium ions and can therefore enable continuous and repeated redox reactions at an electrode to obtain a lithium secondary battery with high capacity and longer cycle life.

[0050] The silicon-based active material can be, for example, Si, SiO m , Si-C composite, Si-Q alloy or a combination thereof, where m satisfies 0 <m≤2, wobei Q ein Alkalimetall, ein Erdalkalimetall, ein Element der Gruppe 13 bis 16, ein Übergangsmetall, ein Seltene-Erden-Element oder eine Kombination davon sein kann, und wobei Si von Q ausgeschlossen ist.

[0051] The metal-based active materials that can be alloyed with lithium may be, for example, B, Al, Ga, In, Ge, Sn, Pb, P, As, Sb, Bi, Mg, Ca, Zn, Cd, Pd, Ag, Au, Pt, an alloy thereof or an oxide thereof.

[0052] The lithium-containing active material can be, for example, lithium-containing titanium complex oxide (LTO, for example complex titanium oxide).

[0053] The first conductive material may comprise at least one selected from the group consisting of graphite, activated carbon, carbon black, acetylene black, Ketjen black (e.g., Ketjen black), carbon nanotubes, graphene, and carbon fibers.

[0054] In one embodiment, any one of a region of the first anode active material or a region of the first conductive material and another of a region of the first anode active material or a region of the conductive material may be connected by the first binder in the form of a discontinuous column (or a wire, e.g., a discontinuous wire) to form a three-dimensional network structure.That is, any one area of ​​a region of the first anode active material or the first conductive material and another area of ​​a region of the first anode active material or the first conductive material may be connected by a binder in the form of a discontinuous column (or a wire) to form a complex having a three-dimensional network structure in a net shape (the active materials, for example, the active materials or the conductive materials are located at the intersection points, and a linear binder connects the materials).

[0055] Such a three-dimensional network structure may result from the strong pi-pi interactions between the first hard block and the second hard block contained in the triblock copolymer and the first anode active material or the first conductive material. In this case, the region of the first anode active material or the region of the first conductive material and the first binder, which is in the form of a discontinuous column, can be bonded to form a three-dimensional network structure, and accordingly, the first self-supporting film can exhibit excellent tensile strength.

[0056] In one embodiment, the first binder may have an average width perpendicular to a longitudinal direction of 0.1 µm to 2 µm, preferably from 0.2 µm to 0.8 µm, and more preferably from 0.3 µm to 0.7 µm. In this case, the average width perpendicular to a longitudinal direction with respect to the first binder in the form of pillars included in the first self-standing film is a value obtained by measuring a width perpendicular to a longitudinal direction at both ends and in the middle along the longitudinal direction with respect to the first binder of five randomly selected pillars and averaging these measured values ​​using an image of the first binder particles observed with a scanning electron microscope (SEM, e.g., scanning electron microscope).

[0057] In one embodiment, the first glass transition temperature and the second glass transition temperature associated with the first hard block and the second hard block may be 50°C to 120°C, and the third glass transition temperature associated with the soft block may be -120°C to -50°C. Preferably, the first glass transition temperature and the second glass transition temperature may be 80°C to 120°C, and the third glass transition temperature may be -120°C to -80°C. More preferably, the first glass transition temperature and the second glass transition temperature may be 80°C to 110°C, and the third glass transition temperature may be -110°C to -80°C.

[0058] Thus, the first hard block, the second hard block, and the soft block contained in the triblock copolymer have a glass transition temperature in the numerical ranges described above, and accordingly, the first self-standing film containing the first binder containing the triblock copolymer can have further improved durability and flexibility and retain the shape more effectively.

[0059] The soft block, the first hard block, and the second hard block included in the triblock copolymer can have independent properties without affecting each other, and accordingly, the soft block can provide appropriate flexibility, and the first hard block and the second hard block can each provide strong bonding strength with the first anode active material or the first binder to form the first self-standing film. Second standalone film

[0060] The second self-standing film comprises a second binder, a second anode active material and a second conductive material.

[0061] The second binder may comprise a fluorine-based resin. The fluorine-based resin may be in a fibrous form and serve as a matrix that supports and binds the second anode active material and the second conductive material.

[0062] The fluorine-based resin may, for example, comprise at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), polyvinylidene fluoride-tetrafluoroethylene (PVDF-TFE), polyvinylidene fluoride-chlorofluoroethylene (PVDF-CTFE), and polytetrafluoroethylene (PTFE). The second anode active material may comprise at least one selected from the group consisting of a carbon-based active material, a silicon-based active material, a metal-based active material that can be alloyed with lithium, and a lithium-containing active material. In this case, the second anode active material may be the same as or different from the first anode active material. The carbon-based active material may, for example, be graphite, hard carbon, soft carbon, or graphene.The graphite can be artificial graphite, natural graphite, a mixture of artificial graphite and natural graphite, natural graphite coated with artificial graphite, or a combination thereof.

[0063] The carbon-based active material changes its crystal structure only slightly during the process of intercalation (e.g., insertion) and deintercalation (e.g., removal) of lithium ions and can therefore enable continuous and repeated redox reactions at an electrode to obtain a lithium secondary battery with high capacity and longer cycle life.

[0064] The silicon-based active material can be, for example, Si, SiO m, Si-C composite, Si-Q alloy or a combination thereof, where m satisfies 0 <m≤2, wobei Q ein Alkalimetall, ein Erdalkalimetall, ein Element der Gruppe 13 bis 16, ein Übergangsmetall, ein Seltene-Erden_Element oder eine Kombination davon sein kann, und wobei Si von Q ausgeschlossen ist.

[0065] The metal-based active materials that can be alloyed with lithium can be, for example, B, Al, Ga, In, Ge, Sn, Pb, P, As, Sb, Bi, Mg, Ca, Zn, Cd, Pd, Ag, Au, Pt, an alloy thereof or an oxide thereof.

[0066] The lithium-containing active material can, for example, be lithium-containing titanium complex oxide (LTO).

[0067] The second conductive material may comprise at least one selected from the group consisting of graphite, activated carbon, carbon black, acetylene black, Ketjen black (e.g., Ketjen black), carbon nanotubes, graphene, and carbon fibers. In this case, the second conductive material may be identical to or different from the first conductive material. Laminat

[0068] The laminate may comprise the first self-standing film and the second self-standing film.

[0069] The first self-standing film may comprise the first binder comprising the triblock copolymer and excellent mechanical properties resulting from the first hard block and the second hard block of the triblock copolymer, as well as excellent adhesion to a current collector through pi-pi interactions resulting from an aromatic ring structure contained in the repeating units of the first hard block and the second hard block.

[0070] The second self-standing film may comprise a second binder containing a fluorine-based resin, and in particular, the second binder containing a fluorine-based fibrous resin may have excellent flexibility resulting from the fibrous binder.

[0071] As described above, the first self-standing film and the second self-standing film contain different types of binders, and accordingly, the first self-standing film and the second self-standing film may have different physical properties. That is, the first self-standing film may have greater mechanical properties (e.g., greater mechanical strength) and greater adhesion to a current collector than the second self-standing film, and the second self-standing film may have greater flexibility than the first self-standing film.

[0072] In this case, the laminate containing both the first self-standing film and the second self-standing film can be well balanced with a combination of excellent mechanical properties resulting from the first self-standing film, excellent adhesion to a current collector, and excellent flexibility resulting from the second self-standing film.

[0073] In one embodiment, the laminate may have an average thickness of 30 µm to 500 µm, preferably 100 µm to 400 µm, and more preferably 150 µm to 250 µm. In this case, if the average thickness of the laminate satisfies the above-described ranges, the laminate can obtain sufficient mechanical properties and also low resistance (e.g., low electrical resistance) to have improved performance characteristics (e.g., output characteristics, e.g., improved output / output characteristics) when applied to lithium secondary batteries.

[0074] In one embodiment, the laminate may have various types of stacking structures, including the first self-standing film and the second self-standing film.

[0075] For example, the laminate may have a two-layer structure in which the first self-standing film and the second self-standing film are stacked one after the other.

[0076] As another example, the laminate may have a three-layer structure in which the first self-standing film is stacked on an upper side and a lower side of the second self-standing film (e.g., a first self-standing film is associated with each other). As another example, the laminate may have a structure with repeated alternating stacking structures of the first self-standing film and the second self-standing film (e.g., a four-layer structure of the first self-standing film / second self-standing film / first self-standing film / second self-standing film, or a stacking structure with more than four overlapping layers).Consequently, when the laminate has a structure with repeated three-layer structures or alternating stack structures, the laminate can have further improved physical properties because self-standing films with different physical properties are evenly distributed throughout the laminate.

[0077] In one embodiment, the first self-standing film and the second self-standing film may be present in a thickness ratio of 1:0.01 to 1:0.49, 1:0.05 to 0.42, 1:0.07 to 0.35, or 1:0.1 to 0.29. In this case, when the thickness ratio of the first self-standing film and the second self-standing film satisfies the above-described ranges, the laminate can sufficiently secure (e.g., ensure) excellent physical properties derived from each of the first self-standing film and the second self-standing film, and also the content of the triblock copolymer having excellent negative potential stability can be sufficiently larger than the content of the fluorine-based resin having relatively poor negative potential stability compared to the triblock copolymer to further improve the cycle life characteristics of a lithium secondary battery to which the laminate is applied. Anode for lithium secondary battery

[0078] An anode for the lithium secondary battery of the present invention comprises the above-described self-standing film laminate for an anode of a lithium secondary battery and a current collector (for example, a current collector, for example, a current collector).

[0079] There are no specific limitations on the current collector, as long as the current collector has high conductivity without causing chemical changes in the anode. For example, stainless steel, aluminum, nickel, titanium, burnt carbon, copper, an alloy thereof, or stainless steel surface-treated with carbon, nickel, titanium, silver, or the like can be used as the current collector.

[0080] The current collector can be disposed on one side of the first self-standing film as an outermost layer in the self-standing film laminate for a lithium secondary battery anode. As described above, the triblock copolymer contained in the first self-standing film can exhibit excellent adhesion to the current collector through pi-pi interactions resulting from the aromatic ring structure contained in the repeating units of the first hard block and the second hard block. Accordingly, when the current collector is disposed on the side of the first self-standing film, the adhesion between the self-standing film laminate for a lithium secondary battery anode and the current collector can be improved.

[0081] In one embodiment, in the current collector, a primer layer (e.g., a primer layer) containing a carbon-based material may be formed on a surface of a side on which the self-standing film laminate for an anode of the lithium secondary battery is disposed. The carbon-based material may, for example, include at least one selected from the group consisting of graphite, graphene, carbon black, Denka black (e.g., DenkaBlack), acetylene black, Ketjen black, channel black, furnace black, lamp black, gap black, carbon nanotubes, graphite fibers, and carbon fibers.The carbon-based material contained in the primer layer can exhibit excellent adhesion to the first self-standing film through pi-pi interactions with the aromatic ring structure contained in the repeating units of the first hard block and the second hard block. Accordingly, the adhesion between the self-standing film laminate for a lithium secondary battery anode and the current collector can be further improved when the primer layer is formed. Lithium secondary battery

[0082] A lithium secondary battery according to the present invention may comprise the above-described anode for a lithium secondary battery, a cathode for a lithium secondary battery and an electrolyte.

[0083] The cathode for a lithium secondary battery may comprise at least one cathode active material (e.g., a cathode active material, e.g., a cathode active material) selected from the group consisting of lithium, nickel, cobalt, manganese, iron, tin, silicon, aluminum, and a mixture thereof. For the cathode for a lithium secondary battery, for example, cathode active materials such as LiCoO 2 , LiMnO 2 , LiFeO 2 , Li(Ni 0.6 Mn 0.2 Co 0.2 ) O 2 , Li(Ni 0.7 Mn 0.15 Co 0.15 ) O 2 , Li(Ni 0.8 Mn 0.1 Co 0.1 ) O 2 , Li (Ni 0.9 Mn 0.05 Co 0.05 ) O 2 , LiNi 0.6 Co 0.2 0Al 0.2 O 2 , LiNi 0.7 Co 0.2 0Al 0.1 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiNi 0.85 Co 0.1 Al 0.05 O2 , LiNi 0.88 Co 0.1 Al 0.02 O 2 , LiMn 2 O 4 , and LiFePO 4 be used.

[0084] The electrolyte can be a liquid electrolyte (e.g. a liquid electrolyte) or a solid electrolyte (e.g. a solid electrolyte).

[0085] If the electrolyte is a liquid electrolyte, it may contain a lithium salt and a non-aqueous organic solvent.

[0086] The lithium salt can be used without restriction as long as the lithium salt is commonly used for the electrolyte of lithium secondary batteries. For example, the lithium salt may comprise at least one compound selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 )2 , CF 3 SO 3 Li, LiC(CF 3 SO 2 ) 3 , LiC 4 BO 8 , LiTFSI, LiFSI, and LiClO 4 .

[0087] The non-aqueous organic solvent may be a type of organic solvent that can be used as a non-aqueous electrolyte in manufacturing typical lithium secondary batteries. In this case, the non-aqueous organic solvent may be contained in an amount appropriately controlled within a generally acceptable range. Specifically, the non-aqueous organic solvent may include typical organic solvents that can be used as non-aqueous organic solvents for lithium secondary batteries, such as cyclic carbonate solvents, linear carbonate solvents, ester solvents, or ketone solvents. These solvents can be used either singly or in combination of two or more.

[0088] The cyclic carbonate solvent may comprise at least one selected from the group consisting of ethylene carbonate (EC), vinylene carbonate (VC), fluoroethylene carbonate (FEC), propylene carbonate (PC), and butylene carbonate (BC).

[0089] The linear carbonate solvent may comprise at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), and ethyl propyl carbonate (EPC).

[0090] The ester solvent may comprise at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, δ-valerolactone and ε-caprolactone.

[0091] Polymethyl vinyl ketone and the like can be used as ketone solvents.

[0092] If the electrolyte is a liquid electrolyte, the lithium secondary battery may further contain a separator (for example, a separating agent).

[0093] As the separator, a typically used porous polymer film, for example, a porous polymer film made of a polyolefin-based polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, can be used alone or in lamination (for example, coating) therewith, or a typical porous nonwoven fabric (for example, nonwoven fabric), such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, can be used, but the separator is not limited to these. Further, a coated separator having a ceramic component or a polymer component can be used to ensure heat resistance or mechanical strength, and the separator can have a single-layer or multi-layer structure.

[0094] In this case, the porous separator can generally have a pore diameter of 0.01 to 50 µm and a porosity of 5 to 95%. In addition, the porous separator can generally have a thickness of 5 to 300 µm.

[0095] Meanwhile, if the electrolyte is a solid electrolyte, the electrolyte may be a polymer-based solid electrolyte, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, or a mixture thereof. The polymer solid electrolyte may include, for example, a polyether-based polymer, a polycarbonate-based polymer, an acrylate-based polymer, a polysiloxane-based polymer, a phosphazene-based polymer, a polyethylene derivative, an alkylene oxide derivative such as polyethylene oxide, a phosphoric acid ester polymer, polyagitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, and a derivative thereof, and a polymer having an ionic dissociation group.In addition, the polymer electrolyte is preferably a polymer resin and may be, for example, a branched copolymer in which an amorphous polymer such as PMMA, polycarbonate, polysiloxane and / or phosphazene is copolymerized with a PEO (polyethylene oxide) main chain as a comonomer, a honeycomb-like (e.g., comb-like) polymer resin and a crosslinked polymer resin, at least one kind (e.g., one type) of which may be included.

[0096] The oxide-based solid electrolyte can be, for example, an LLZO-based compound, an LLTO-based compound such as Li 3x La 2 / 3-x TiO 3 , a LISICON-based compound such as Li 14 Zn(GeO 4 ) 4 , a LATP-based compound such as Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 , a LAGP-based compound such as (Li 1+x Ge 2-x Al x (PO 4 ) 3), and a LIPON-based compound, but is not specifically limited to these.

[0097] The sulfide-based solid electrolyte may comprise at least one of Li 6 PS 5 Cl, Li 2 SP 2 S 5 , Li 2 S-LiI-P 2 S 5 , Li 2 S-LiI-Li 2 Surgery 2 S 5 , Li 2 S-LiBr-P 2 S 5 , Li 2 S-Li 2 Surgery 2 S 5 , Li 2 SLi 3 PO 4 -P 2 S 5 , Li 2 SP 2 S 5 -P 2 O 5 , Li 2 SP 2 S 5 -SiS 2 , Li 2 SP 2 S 5 -SnS, Li 2 SP 2 S 5 -Al 2 S 3 , Li 2 S-GeS 2 , or Li 2 S-GeS 2 -ZnS, but is not specifically limited to it. Method for producing a self-standing film laminate for an anode of a lithium secondary battery

[0098] The following describes a method for manufacturing the self-standing film laminate for a lithium secondary battery anode of the present invention, and no overlapping descriptions are given for the self-standing film laminate for a lithium secondary battery anode and the components included therein. The method for manufacturing the self-standing film laminate for a lithium secondary battery anode may include stacking the first self-standing film and the second self-standing film.

[0099] In one embodiment, stacking may include calendering (rolling). That is, the first self-standing film and the second self-standing film may be overlapped, passed between two rolls, pressed, and rolled to form (e.g., mold) the self-standing film laminate for an anode of a lithium secondary battery.

[0100] In this case, when the self-standing film laminate for a lithium secondary battery anode includes two or more first self-standing films and / or two or more second self-standing films (e.g., a three-layer structure of first self-standing film / second self-standing film / first self-standing film), the stacking may include arranging a plurality of self-standing films constituting the self-standing film laminate for a lithium secondary battery anode to overlap according to the stacking order, and then passing the self-standing films between a pair of rollers for pressing and rolling. That is, the stacking of the first self-standing film and the second self-standing film may be alternately stacking the first self-standing film and the second self-standing film.

[0101] In one embodiment, the stacking of the first self-standing film and the second self-standing film can be performed at 50 to 160°C, 60 to 130°C, or 80 to 120°C, and preferably at a temperature equal to or higher than the first glass transition temperature and the second glass transition temperature corresponding to the first hard block and the second hard block, and equal to or higher than the glass transition temperature of the fluorine-based resin. In this case, when the stacking of the first self-standing film and the second self-standing film is performed within the temperature ranges described above, the flowability and molding properties of the first binder and the second binder are sufficiently secured during stacking, and accordingly, the adhesion between the first self-standing film and the second self-standing film can be further improved.

[0102] In one embodiment, the method for manufacturing the self-standing film laminate for a lithium secondary battery anode may include a film manufacturing process (e.g., a sheet manufacturing process) for independently manufacturing the first self-standing film and the second self-standing film. That is, the method for manufacturing the self-standing film laminate for a lithium secondary battery anode may include stacking the first self-standing film and the second self-standing film, which are separately manufactured by different film manufacturing processes.

[0103] In one embodiment, the first self-standing film can be obtained by a film-forming method using a composition (e.g., a mixture) for forming a first self-standing film containing the first anode active material, the first conductive material, and the first binder. In this case, the first binder in the composition for forming the first self-standing film can contain particles (e.g., particles) of the triblock copolymer having an average diameter (D 50 ) from 1 µm to 50 µm. The average diameter (D 50 ) indicates a diameter corresponding to 50% of the cumulative volume distribution (e.g., larger than the individual diameter of 50% of the particles) measured by a laser diffraction / scattering particle size distribution meter.

[0104] The first binder (e.g., the particles of the first binder) in the composition for forming the first self-standing film is (e.g., are) substantially spherical, and may (e.g., may) be truly spherical or nearly truly spherical, and may (e.g., may) in particular have an average sphericity of 0.7 to 1.0, preferably 0.8 to 1.0, and more preferably 0.9 to 1.0. That is, before producing the first self-standing film, the particles of the first binder in the composition for forming the first self-standing film containing the first binder may be dispersed (e.g., distributed) in the composition for forming the first self-standing film while substantially maintaining the spherical shape.

[0105] In this case, the sphericity of the first binder in the composition for forming the first self-standing film is a value obtained by measuring the major and minor diameters (for example, the largest and smallest diameters) of 10 randomly selected particles by using images of binder particles observed through a scanning electron microscope (SEM), calculating the ratio of minor diameter / major diameter of each particle, and finding the average value of the ratio of minor diameter / major diameter, and the closer the sphericity is to 1, the more sphere-like the particle (for example, the particles) is.

[0106] In one embodiment, the method for producing the first self-standing film may be performed by calendering (rolling). That is, the composition for forming the first self-standing film, which includes the first anode active material, the first conductive material, and the first binder, may be passed between a pair of rollers and pressed and rolled to form the first self-standing film.

[0107] In this case, at the beginning of the film-forming process, contact occurs between the first binder containing the substantially spherical (e.g., spherical) triblock copolymer and the first anode active material or the first conductive material by a high external force (shear force, tensile force, and the like), and then, as the external force decreases in the rear part (e.g., at the rear end) of the film-forming process, the distance between the first anode active materials or the first conductive materials increases (e.g., correspondingly, for example), and thus the first binder containing the triblock copolymer in contact with a surface of the first anode active material or the first conductive material can be flexibly deformed while maintaining the bond to have a discontinuous columnar or wire-like linear shape.

[0108] In one embodiment, the first self-supporting film can be formed at a temperature equal to or higher than the first glass transition temperature and the second glass transition temperature associated with the first hard block and the second hard block. The first hard block and the second hard block form a crosslink (bond) through a physical bond with a relatively low bond energy and can therefore remain the same shape and size below the glass transition temperature, but can be easily shaped above the glass transition temperature.Accordingly, when the film-forming process of the first self-standing film is performed at a temperature equal to or higher than the first glass transition temperature and the second glass transition temperature, each hard block contained in the triblock copolymer is flexibly deformed while maintaining a bond with the first anode active material or the first conductive material, and thus the first binder portion (for example, the first binder part) can provide a physical crosslinking point (connection point) having a linear (non-continuous columnar or wire-like) shape to form a solid three-dimensional network structure around the point.In one embodiment, the second self-standing film can be obtained by a film-forming method using a second self-standing film-forming composition containing the second anode active material, the second conductive material, and the second binder. In one embodiment, the second self-standing film-forming method can be performed by calendering (rolling). That is, the second self-standing film-forming composition containing the second anode active material, the second conductive material, and the second binder can be passed between a pair of rollers and pressed and rolled to form the second self-standing film.

[0109] In one embodiment, the film formation of the second self-standing film can be performed at 60 to 160°C, 70 to 150°C, or 75 to 145°C, preferably at a temperature equal to or higher than the glass transition temperature of the fluorine-based resin. In this case, when the film formation of the self-standing film is performed at the above-described temperature, sufficient flexibility of the second binder can be achieved, and accordingly, the bond between the second binder and the second anode active material and / or the second conductive material is effectively maintained, and also the second binder can be flexibly deformed to facilitate the molding of the second self-standing film.

[0110] In one embodiment, the film forming process of the first self-standing film and the film forming process of the second self-standing film can each be performed in a dry process. That is, the first self-standing film and the second self-standing film are each formed in a dry manner, and the composition for forming the first self-standing film and the composition for forming the second self-standing film preferably each contain substantially no solvent. When the film forming process is performed using a wet process, there is a limit to increasing a charge amount of an electrode due to a liquid slurry (e.g., slurry, e.g., a liquid slip), and a network structure between the binder and the active material / conductive material may not be formed in some cases.However, since the film forming process according to the present invention is preferably carried out using a dry method, a high electrode charge amount enabling a high energy density is achievable and a network structure between the binder and the active material can be formed more effectively. Method for producing an anode for a lithium secondary battery

[0111] A method for producing an anode for a lithium secondary battery according to the present invention will be described below, wherein overlapping descriptions for the anode for a lithium secondary battery and the components contained therein will not be given (for example, will be made).

[0112] The method for manufacturing an anode for a lithium secondary battery may comprise the above-described method for manufacturing a self-standing film laminate for an anode of a lithium secondary battery and disposing a current collector on one side of the first self-standing film as an outermost layer in the self-standing film laminate for an anode of a lithium secondary battery.

[0113] In one embodiment, the current collector may be arranged by calendering (rolling). That is, when the first self-standing film as the outermost layer in the self-standing film laminate for a lithium secondary battery anode and the current collector are arranged opposite each other (e.g., facing each other), the current collector and the self-standing film laminate for a lithium secondary battery anode may be passed between a pair of rollers and pressed and rolled to form the anode for a lithium secondary battery.

[0114] In one embodiment, the application of the current collector (e.g., calendering) can be performed at 80 to 200°C, 90 to 170°C, or 95 to 145°C, and preferably at a temperature equal to or higher than the first glass transition temperature and the second glass transition temperature associated with the first hard block and the second hard block, respectively. In this case, if the application of the current collector is performed within the temperature ranges described above, sufficient adhesion between the current collector and the first self-supporting film can be achieved.

[0115] The present invention will now be described in more detail with reference to examples. However, these examples are provided to assist in understanding the present invention, and the scope of the present invention is in no way limited to these examples. Example 1 Self-standing film laminate for an anode of a lithium secondary battery in which a first self-standing film and a second self-standing film are arranged one above the other (for example, stacked). Production Example 1-1: Production of the first self-standing film with SBS binder

[0116] Graphite as an anode active material, carbon black as a conductive material, and SBS triblock copolymer as a binder (glass transition temperature of the polystadene block: 100 °C, glass transition temperature of the polybutadiene block: -100 °C) were mixed without solvent in a mass ratio of 96:1:3.

[0117] The mixed powder was rolled (e.g. rolled, e.g. pressed, e.g. pressed by rollers) into a self-supporting film using a 2-roll press heated to 120 °C. Production example 1-2: Production of a second self-standing film with PTFE binder

[0118] Graphite as an anode active material, carbon black as a conductive material, and PTFE as a binder were mixed without solvent in a mass ratio of 96:1:3. The mixed powder was rolled into a self-supporting film using a two-roll press heated to 80 °C. Production example 1-3: Production of laminate

[0119] The first self-standing film (Production Example 1-1) and the second self-standing film (Production Example 1-2) were overlapped and then rolled into a laminate using a 2-roll press heated to 100 °C.

[0120] In this case, the laminate produced had an average thickness of 200 µm, and the first self-standing film contained in the laminate and the second self-standing film contained in the laminate had a thickness ratio of 1:0.25. Comparative Example 1: Self-supporting film for an anode of a lithium secondary battery with PTFE as a binder

[0121] Graphite as an anode active material, carbon black as a conductive material, and PTFE as a binder were mixed without solvent in a mass ratio of 96:1:3. The mixed powder was rolled with a two-roll press heated to 80 °C to produce a self-supporting film with an average thickness of 200 µm. Reference Example 1: Self-standing film for an anode of a lithium secondary battery with SBS as a binder

[0122] Graphite as an anode active material, carbon black as a conductive material, and SBS triblock copolymer as a binder (glass transition temperature of the polystadene block: 100 °C, glass transition temperature of the polybutadiene block: -100 °C) were mixed without solvent in a mass ratio of 96:1:3.

[0123] The mixed powder was rolled with a 2-roll press heated to 120 °C to produce a self-standing film with an average thickness of 200 µm. Experimental Example 1: SEM image observation of the mixed powder from Preparation Example 1-1 and the first independent film produced therefrom

[0124] An SEM image was taken for the first self-standing film prepared according to Preparation Example 1-1 and is shown in Fig. 1A and Fig. 1B, and before preparing the first self-standing film, SEM images were taken for mixed powder of an anode active material (graphite), a conductive material (carbon black), and a binder (SBS triblock copolymer) and are shown in Fig. 2A, and in this case the SEM image taken only for the SBS powder is in Fig. 2B.

[0125] Referring to Fig. 1A and Fig.1B, it can be seen that the columnar SBS binder after the film formation process forms a network structure connecting between anode active materials, between conductive materials, or between anode active materials and conductive materials, and has the shape of a column with an average width perpendicular to the longitudinal direction of about 0.4 to 0.5 µm.

[0126] Fig.Figure 1C schematically shows a columnar SBS binder connecting any one of the anode active material or the conductive material and any other of the anode active material or the conductive material in the network structure of the first self-standing film prepared according to Production Example 1-1. In this case, it can be seen that the SBS binder in the form of a discontinuous column makes point contact with an outer surface of each of an active material region or a conductive material region (e.g., point contact with an outer surface of each active material region and each conductive material region), thereby forming a structure connecting the (e.g., all) regions. Referring to Fig.2A, it can be seen that SBS is dispersed (e.g., distributed) in the mixed powder, maintaining an almost spherical shape (average diameter (D50): 8 D 50 , average sphericity: 0.95), and that, as in Fig. 2B, the SBS powder is also nearly spherical before preparing the mixed powder described above. Experimental example 2: Evaluation of adhesion (e.g. adhesive strength) on the pantograph

[0127] A current collector (e.g., a copper film, e.g., an 8 μm thick copper foil from Nexilis) coated with a primer layer (Ketjen black) and (e.g., associated) the self-standing film laminate of Example 1, the self-standing film of Comparative Example 1, and the self-standing film of Reference Example 1 were (e.g., each) rolled with a 2-roll press heated to 100°C to produce (e.g., each) an anode for a lithium secondary battery. In this case, the first self-standing film included in the self-standing film laminate of Example 1 was arranged to oppose (e.g., face) the primer layer coated on the current collector.

[0128] Thereafter, a peel test (e.g., a peeling test, e.g., a flaking test) was performed on the current collector and (e.g., associated) the self-standing film laminate or the self-standing film according to the standards of ASTM D1876, and the results are shown in Table 1 below. Experimental Example 3: Evaluation of Flexibility

[0129] A cylindrical rod having an average diameter of 10 mm was wound with the self-standing film laminate of Example 1, the self-standing film of Comparative Example 1, and the self-standing film of Reference Example 1, and then the occurrence of cracks was evaluated with the naked eye, the results of which are shown in Table 1 below. Test example 4: Evaluation of tensile strength and elongation

[0130] In order to evaluate the tensile strength of the self-standing film laminate of Example 1, the self-standing film of Comparative Example 1, and the self-standing film of Reference Example 1, each self-standing film was punched with a width of 2 cm and a height (e.g., a depth) of 6 cm to prepare (e.g., prepare) samples, and the samples were measured (e.g., measured) while being pulled at a speed of 5 mm / min using UTM equipment (e.g., a universal testing machine) to obtain a strain-length dependency diagram of stress (e.g., tensile), and based on the diagram, the tensile strength and elongation were measured, and the results are shown in Table 1 below.

[0131] In this case, the tensile strength was measured by dividing the tensile stress measured in the graph by the cross-sectional area of ​​the (e.g., the respective) sample, and the elongation was measured as the ratio of the elongation length between the yield stress and tensile stress measured in the graph. [Table 1] Adhesive strength [gf / mm] flexibility Tensile strength [MPa] Elongation [%] Example 1 3 Good 0,7 2 Comparison example 1 1, 2 Good 0,1 5,5 Reference example 1 3 Bad 0,7 2

[0132] Referring to Table 1, it was found that the self-standing film laminate of Example 1 has excellent adhesion to the current collector and excellent tensile strength.

[0133] Furthermore, it was found that the self-standing film laminate of Example 1 has a relatively low elongation at a level suitable for use in a roll-to-roll process and also has excellent flexibility (see Fig. 3A).

[0134] In contrast, the self-standing film of Comparative Example 1 was found to have excellent flexibility (see Fig. 3B), but has poorer adhesion to the current collector and lower tensile strength than the self-standing film laminate of Example 1, and that the self-standing film of Reference Example 1 has poorer flexibility (see Fig. 3C) and has an excessively higher elongation than the self-standing film laminate of Example 1. Test example 5: Evaluation of tensile strength as a function of the width of the produced film

[0135] The tensile strength of the self-standing film laminate of Example 1, the self-standing film of Comparative Example 1, and the self-standing film of Reference Example 1 was measured (for example, respectively) when the width of the produced film was set to 100 mm, 200 mm, and 300 mm, and the results are shown in Table 2 below. In this case, the tensile stress measured in Experimental Example 4 was multiplied by the cross-sectional area of ​​the self-standing film laminate or the self-standing film with different widths of the produced films to measure the tensile strength. [Table 2] Width of the produced film [mm] Tensile strength [N] Example 1 Comparison example 1 Reference example 1 100 12,6 1,65 16,1 200 25,2 3,3 32,2 300 37,8 4,95 48,3

[0136] Referring to Table 2, the self-standing film laminate of Example 1, like the self-standing film of Reference Example 1, showed excellent overall tensile strength regardless of the film manufacturing width values ​​of 100 mm, 200 mm and 300 mm.

[0137] In contrast, the self-standing film of Comparative Example 1 exhibited lower tensile strength at all film-forming widths of 100 mm, 200 mm, and 300 mm, which was below the minimum tensile strength of 5 N for application on conventional roll presses. A self-standing film laminate for a lithium secondary battery anode of the present invention can exhibit excellent adhesion resulting from a triblock copolymer contained as a binder in a first self-standing film, excellent mechanical properties, satisfactory elongation, and excellent flexibility resulting from a fluorine-based resin contained as a binder in a second self-standing film.

[0138] While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the scope of the invention as defined by the appended claims.

Claims

[1] A self-standing film laminate suitable for an anode of a lithium secondary battery, the self-standing film laminate comprising: a first self-standing film comprising a first anode active material, a first conductive material and a first binder comprising a triblock copolymer, and a second self-standing film comprising a second anode active material, a second conductive material and a second binder comprising a fluorine-based resin, wherein the triblock copolymer comprises a soft block derived from aliphatic or cycloaliphatic diene-based monomers and having a rubber phase at room temperature, and a first hard block and a second hard block connected to both ends of the soft block, which are derived from an ethylenically unsaturated monomer containing an aromatic ring and which have a glass phase at room temperature, and the first binder is in the form of a discontinuous column that provides a connection between any one of i) a region of the first anode active material or ii) a region of the first conductive material and a) another one of a region of the first anode active material or b) a region of the first conductive material. [2] The self-standing film laminate according to claim 1, wherein the first self-standing film and the second self-standing film are in a thickness ratio of 1:0.01 to 1:0.

49. [3] The self-standing film laminate according to claim 1 or 2, which has a three-layer structure in which the first self-standing film is stacked on an upper side and a lower side of the second self-standing film, respectively. [4] A self-standing film laminate according to any one of claims 1 to 3, which has a repeating alternating stack structure of the first self-standing film and the second self-standing film. [5] The self-standing film laminate according to any one of claims 1 to 4, wherein the region of the first anode active material or the region of the first conductive material and the first binder having the shape of a discontinuous column are bonded to form a three-dimensional network structure. [6] A self-standing film laminate according to any one of claims 1 to 5, wherein the first binder has an average width perpendicular to a longitudinal direction of 0.1 µm to 2 µm. [7] The self-standing film laminate according to any one of claims 1 to 6, wherein a first glass transition temperature and a second glass transition temperature associated with the first hard block and the second hard block are independently 50°C to 120°C, and a third glass transition temperature associated with the soft block is -120°C to -50°C. [8] The self-standing film laminate according to any one of claims 1 to 7, wherein the soft block is derived from an aliphatic diene-based monomer comprising at least one selected from the group consisting of a butadiene-based monomer, a pentadiene-based monomer, and a hexadiene-based monomer. [9] A self-standing film laminate according to any one of claims 1 to 8, wherein the first hard block and the second hard block are each independently derived from an aromatic ring-containing ethylenically unsaturated monomer comprising at least one of a styrene-based monomer and an aromatic (meth)acrylic-based monomer. [10] The self-standing film laminate for an anode of a lithium secondary battery according to any one of claims 1 to 9, wherein the fluorine-based resin comprises at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), polyvinylidene fluoride-tetrafluoroethylene (PVDF-TFE), polyvinylidene fluoride-chlorofluoroethylene (PVDF-CTFE), and polytetrafluoroethylene (PTFE). [11] Anode for a lithium secondary battery, comprising: a pantograph; and the self-standing film laminate for an anode of a lithium secondary battery according to any one of claims 1 to 10, wherein the current collector is disposed on one side of a first self-standing film as an outermost layer in the self-standing film laminate for an anode of a lithium secondary battery. [12] The anode for a lithium secondary battery according to claim 11, wherein the current collector comprises a primer layer containing a carbon-based material formed on a surface of a side on which the self-standing film laminate for an anode of a lithium secondary battery is arranged. [13] Lithium secondary battery comprising: the anode for a lithium secondary battery according to claim 11 or 12, a cathode for a lithium secondary battery, and an electrolyte. [14] A method of manufacturing a self-standing film laminate for an anode of a lithium secondary battery, the method comprising: Stacking a first self-standing film comprising a first anode active material, a first conductive material, and a first binder comprising a triblock copolymer, and a second self-standing film comprising a second anode active material, a second conductive material, and a second binder comprising a fluorine-based resin, wherein the triblock copolymer comprises a soft block derived from aliphatic or cycloaliphatic diene-based monomers and having a rubber phase at room temperature, and a first hard block and a second hard block connected to both ends of the soft block, which are derived from an ethylenically unsaturated monomer containing an aromatic ring and which have a glass phase at room temperature, and the first binder is in the form of a discontinuous column that provides a connection between any one of a region of the first anode active material or a region of the first conductive material and another of a region of the first anode active material or a region of the first conductive material. [15] The method according to claim 14, wherein the first self-standing film is obtained by a film-forming method using a composition for forming a first self-standing film containing the first anode active material, the first conductive material and the first binder, and the first binder in the composition for forming a first self-standing film comprises triblock copolymer particles having an average diameter (D 50 ) from 1 µm to 50 µm. [16] The method according to claim 14 or 15, wherein the first binder in the composition for forming a first self-supporting film is spherical and comprises particles having an average sphericity of 0.8 to 1.

0. [17] The method according to any one of claims 14 to 16, wherein the first self-standing film and the second self-standing film are obtained using a dry film production method. [18] The method according to any one of claims 14 to 17, wherein film formation of the first self-standing film is carried out at a temperature equal to or higher than a first glass transition temperature and a second glass transition temperature associated with the first hard block and the second hard block. [19] The method of any one of claims 14 to 18, wherein stacking the first self-standing film and the second self-standing film comprises alternately stacking the first self-standing film and the second self-standing film. [20] A method of manufacturing an anode for a lithium secondary battery, the method comprising: the method for producing a self-standing film laminate for an anode of a lithium secondary battery according to any one of claims 14 to 19, and Disposing a current collector on one side of the first self-standing film as an outermost layer in the self-standing film laminate for an anode of a lithium secondary battery.

Images