Negative electrode active material, method for producing negative electrode active material, negative electrode composition, negative electrode for lithium secondary battery containing the same, and lithium secondary battery containing the negative electrode

Abstract

The present application relates to a negative electrode active material, a method for manufacturing the negative electrode active material, a negative electrode composition, a negative electrode for a lithium secondary battery including the same, and a lithium secondary battery including the negative electrode.

Description

Technical Field

[0001] This application claims the benefit of the filing date of Korean Patent Application No. 10-2022-0110078, filed with the Korean Intellectual Property Office on August 31, 2022, and all of its contents are incorporated herein by reference.

[0002] This application relates to a negative electrode active material, a method for manufacturing the same, a negative electrode composition, a negative electrode for a lithium secondary battery including the same, and a lithium secondary battery including the negative electrode.

Background Art

[0003] Due to the rapid increase in the use of fossil fuels, the demand for alternative and clean energy has been increasing. As part of this, the fields of power generation and energy storage using electrochemical reactions are the most actively studied.

[0004] Currently, a typical example of an electrochemical device using such electrochemical energy is a secondary battery, and its usage area is increasingly expanding.

[0005] As the technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source has been rapidly increasing. Among such secondary batteries, lithium secondary batteries having high energy density, voltage, long cycle life, and low self-discharge rate have been commercialized and widely used. In addition, research on methods for manufacturing high-density electrodes with higher energy density per unit volume as electrodes for such high-capacity lithium secondary batteries has been actively carried out.

[0006] Generally, a secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator. The negative electrode includes a negative electrode active material that inserts and desorbs lithium ions emitted from the positive electrode, and silicon-based particles having a large discharge capacity can be used as the negative electrode active material.

[0007] Especially in recent years, in response to the demand for high-energy-density batteries, research has been actively conducted on methods to increase the capacity by using silicon-based compounds such as Si / C and SiOx, which have a capacity more than 10 times greater than that of graphite-based materials, as the negative electrode active material. However, in the case of silicon-based compounds, which are high-capacity materials, although the capacity is large compared to conventionally used graphite, there is a problem that the volume rapidly expands during the charging process, severing the conductive path and degrading the battery characteristics.

[0008] Therefore, in order to solve the problems when using silicon-based compounds as the negative electrode active material, various solutions have been discussed, such as a solution to adjust the driving potential, a method of further coating a thin film on the active material layer additionally, a solution to suppress the volume expansion itself, such as a method of adjusting the particle size of the silicon-based compound, or various solutions to prevent the conductive path from being severed. However, in the case of the above solutions, they may rather degrade the performance of the battery, so there are limitations in application, and there are still limitations in the commercialization of manufacturing negative electrode batteries with a high content of silicon-based compounds.

[0009] Therefore, even when using a silicon-based active material as the negative electrode active material to improve the capacity performance, research on the silicon-based active material itself that can alleviate the cracking phenomenon of silicon due to the insertion and desorption of lithium during charge and discharge is necessary.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] When producing a silicon-based active material by a chemical processing method instead of a conventional pulverization processing method, it was confirmed that the physical properties of the silicon-based active material itself can be adjusted, and that the reaction occurs uniformly during the insertion / desorption reaction of lithium, reducing the stress on the silicon-based active material. Furthermore, through research, it was confirmed that when producing a silicon-based active material by a chemical processing method, the crystal grain orientation distribution of the silicon-based active material itself can be controlled, and it was confirmed that the insertion and desorption of lithium ions become uniform through crystal grain orientation control.

[0012] Accordingly, the present application relates to a negative electrode active material, a method for manufacturing a negative electrode active material, a negative electrode composition, a negative electrode for a lithium secondary battery including the same, and a lithium secondary battery including the negative electrode, which can solve the above-described problems.

Means for Solving the Problems

[0013] One embodiment of the present specification provides a negative electrode active material including a silicon-based active material including (220) crystal plane and (111) crystal plane, the silicon-based active material satisfying the following Formula 1, the silicon-based active material including one or more selected from the group consisting of SiOx (x = 0) and SiOx (0 < x < 2), and including 70 parts by weight or more of the SiOx (x = 0) based on 100 parts by weight of the silicon-based active material. [Formula 1] 45 ≦ (X / Y) × 100 In Formula 1 above, Y means the ratio of the (111) crystal plane in the silicon-based active material, and X means the ratio of the (220) crystal plane in the silicon-based active material.

[0014] In another embodiment, a method for manufacturing a negative electrode active material includes: chemically reacting silane gas to deposit a silicon-based active material on the crystal nucleus surface; and obtaining the silicon-based active material deposited on the substrate, wherein the silicon-based active material satisfies Formula 1, and a method for manufacturing a negative electrode active material according to the present application is provided.

[0015] In another embodiment, a negative electrode composition including a negative electrode active material, a negative electrode conductive material, and a negative electrode binder according to the present application is provided.

[0016] In another embodiment, a negative electrode for a lithium secondary battery is provided, which includes a negative electrode current collector layer and a negative electrode active material layer provided on one or both surfaces of the negative electrode current collector layer, and the negative electrode active material layer includes the negative electrode composition according to the present application or a cured product thereof.

[0017] Finally, a lithium secondary battery is provided, which includes a positive electrode, a negative electrode for a lithium secondary battery according to the present application, a separator provided between the positive electrode and the negative electrode, and an electrolyte.

Advantages of the Invention

[0018] The negative electrode active material of the present invention, as a silicon-based active material, includes at least one selected from the group consisting of SiOx (x = 0) and SiOx (0 < x < 2). Based on 100 parts by weight of the silicon-based active material, it contains 70 parts by weight or more of the SiOx (x = 0), that is, while having a pure silicon (Pure Si) active material, different from the conventional pulverization processing method, it is produced (silane gas) by controlling the reaction conditions of the chemical method. Thereby, it includes a silicon-based active material satisfying certain physical properties. When the silicon-based active material manufactured in this way is used, it can react uniformly during the insertion and desorption reactions of lithium during charge and discharge, reduce the stress received by the silicon-based active material, and relieve the cracking of particles, thereby improving the life of the electrode.

[0019] In particular, when manufacturing the silicon-based active material as described above, this application is characterized in that the crystal grain orientation distribution satisfying the range of Formula 1 is controlled. That is, when the proportion of the (111) crystal plane is relatively large as in the prior art, the (111) crystal plane has a lower lithium mobility than the (220) crystal plane, and lithium cannot uniformly enter and exit during the insertion and extraction reaction of lithium. However, the silicon-based active material according to this application contains a large proportion of the (220) crystal plane differently from the prior art, and lithium uniformly enters and exits during the insertion and extraction reaction of lithium, and the silicon cracking phenomenon on the electrode surface can be alleviated, thereby having the characteristic of enhancing the life characteristics of the electrode.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0021] Before explaining the present invention, first, several terms are defined. In this specification, when a certain part "includes" a certain component, this means that, unless otherwise stated, it does not exclude other components, but may further include other components.

[0022] In this specification, "p~q" means the range of "p or more and q or less". In this specification, the "specific surface area" is measured by the BET method, specifically calculated from the nitrogen gas adsorption amount at liquid nitrogen temperature (77K) using BELSORP-mini II of BEL Japan, Inc. That is, in this application, the BET specific surface area can mean the specific surface area measured by the above measurement method.

[0023] In this specification, "Dn" means the particle size distribution and means the particle size at the n% point of the cumulative particle number distribution by particle size. That is, D50 is the particle size (average particle size) at the 50% point of the cumulative particle number distribution by particle size, D90 is the particle size at the 90% point of the cumulative particle number distribution by particle size, and D10 is the particle size at the 10% point of the cumulative particle number distribution by particle size. On the other hand, the average particle size can be measured using the laser diffraction method. Specifically, after dispersing the powder to be measured in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (for example, Microtrac S3500), and the difference in the diffraction pattern due to the particle size when the particles pass through the laser beam is measured to calculate the particle size distribution.

[0024] In one embodiment of this application, the particle size or the particle diameter can mean the average diameter or the representative diameter of each grain forming the metal powder.

[0025] In this specification, the meaning that a polymer contains a certain monomer in monomer units means that the monomer participates in the polymerization reaction and is included as a repeating unit in the polymer. In this specification, when it is said that a polymer contains a monomer, this is interpreted in the same way as the polymer containing the monomer in monomer units.

[0026] In this specification, the "polymer" is understood to be used in a broad sense including copolymers unless specified as "homopolymer".

[0027] In this specification, the weight-average molecular weight (Mw) and the number-average molecular weight (Mn) are the polystyrene-equivalent molecular weights measured by gel permeation chromatography (GPC) using monodisperse polystyrene polymers (standard samples) of various degrees of polymerization commercially available for molecular weight measurement as reference substances. In this specification, the molecular weight means the weight-average molecular weight unless otherwise specified.

[0028] Hereinafter, for those with ordinary knowledge in the technical field to which the present invention pertains to easily implement the present invention, a detailed description will be given with reference to the drawings. However, the present invention can be embodied in various different forms and is not limited to the following description.

[0029] One embodiment of this specification includes a silicon-based active material including (220) crystal plane and (111) crystal plane, the silicon-based active material satisfies the following formula 1, the silicon-based active material includes one or more selected from the group consisting of SiOx (x = 0) and SiOx (0 < x < 2), and based on 100 parts by weight of the silicon-based active material, provides a negative electrode active material containing 70 parts by weight or more of the SiOx (x = 0).

[0030] [Formula 1] 45 ≦ (X / Y) × 100 In the above formula 1, Y means the ratio of the (111) crystal plane in the silicon-based active material, X means the ratio of the (220) crystal plane in the silicon-based active material.

[0031] This application is characterized in that when manufacturing a silicon-based active material, the crystal grain orientation distribution satisfying the range of Formula 1 is controlled. That is, when the proportion of the (111) crystal plane is relatively large as in the prior art, the (111) crystal plane has a lower lithium mobility than the (220) crystal plane, and lithium cannot enter and exit uniformly during the lithium insertion / desorption reaction. However, the silicon-based active material according to this application contains a large proportion of the (220) crystal plane differently from the prior art, and lithium can enter and exit uniformly in the lithium insertion / desorption reaction, and the silicon cracking phenomenon on the electrode surface can be alleviated, thereby enhancing the life characteristics of the electrode.

[0032] Figure 4 shows the unit cell structure of the silicon-based active material according to this application. By including the crystal plane, specifically, the (220) plane and the (111) plane of the silicon-based active material can be confirmed in FIG. 5. FIG. 6 corresponds to a diagram comparing the densities of the (220) plane and the (111) plane of the silicon-based active material. As can be specifically confirmed, when the density and direction of the (220) plane, the (110) plane were confirmed, it was confirmed that the (220) plane with a lower particle density within the same area is more advantageous when Li moves.

[0033] In one embodiment of this application, the silicon-based active material includes at least one selected from the group consisting of a spherical silicon-based active material; and a plate-shaped silicon-based active material, and provides a negative electrode active material containing 80 parts by weight or more of the spherical silicon-based active material based on 100 parts by weight of the silicon-based active material.

[0034] In another embodiment, the silicon-based active material includes at least one selected from the group consisting of a spherical silicon-based active material; and a plate-shaped silicon-based active material, and based on 100 parts by weight of the silicon-based active material, it may contain 80 parts by weight or more, 85 parts by weight or more, 90 parts by weight or more of the spherical silicon-based active material, and may contain 100 parts by weight or less, 99 parts by weight or less, 95 parts by weight or less.

[0035] In the present application, the plate-like silicon-based active material means an active material in which the (111) crystal plane of the silicon-based active material is developed and has a wide planar shape instead of a spherical shape. The spherical silicon-based active material means that the (220) crystal plane of the silicon-based active material is more developed than the plate-like silicon-based active material and has spherical particles instead of a widely spreading planar shape.

[0036] That is, the silicon-based active material may have a spherical form, and its sphericity is, for example, 0.8 or more, for example, 0.8 to 0.95, for example, 0.9 to 0.95, for example, 0.93 to 0.95.

[0037] In the present application, the spherical silicon-based active material means an active material having a circularity of 0.9 or more when measuring the circularity of the particles, and an active material having a circularity of less than 0.9 can be classified as a plate-like active material.

[0038] In the present application, the circularity is determined by the following formula 2, where A is the area and P is the boundary line. [Formula 2] 4πA / P 2

[0039] Specifically, the sphericity can be expressed by Formula 2-1 described later, and the sphericity can also be expressed by the formula [4π * actual area of the silicon-based active material / (boundary) 2 .

[0040] In one embodiment of the present application, X means the ratio of the (220) crystal plane in the silicon-based active material, means the ratio based on the entire surface of the silicon-based active material, and X may satisfy 30 to 60, preferably 35 to 60, more preferably 35 to 55.

[0041] In one embodiment of the present application, Y means the ratio of the (111) crystal plane in the silicon-based active material, means the ratio based on the entire surface of the silicon-based active material, and Y may satisfy 50 to 80, preferably 55 to 80, more preferably 55 to 75.

[0042] In one embodiment of the present application, the silicon-based active material may further include various crystal planes.

[0043] In one embodiment of the present application, the silicon-based active material includes at least one selected from the group consisting of SiOx (x = 0) and SiOx (0 < x < 2), and based on 100 parts by weight of the silicon-based active material, the SiOx (x = 0) may be included in an amount of 70 parts by weight or more.

[0044] In one embodiment of the present application, the silicon-based active material includes SiOx (x = 0), and based on 100 parts by weight of the silicon-based active material, the SiOx (x = 0) may be included in an amount of 70 parts by weight or more.

[0045] In another embodiment, based on 100 parts by weight of the silicon-based active material, the SiOx (x = 0) may be included in an amount of 70 parts by weight or more, preferably 80 parts by weight or more, more preferably 90 parts by weight or more, and may be included in an amount of 100 parts by weight or less, preferably 99 parts by weight or less, more preferably 95 parts by weight or less.

[0046] In one embodiment of the present application, as the silicon-based active material, those containing particularly pure silicon (Si) particles may be used. Using pure silicon (Si) particles as the silicon-based active material means that, as described above, based on a total of 100 parts by weight of the silicon-based active material, pure Si particles (SiOx (x = 0)) not bonded to other particles or elements are included within the above range.

[0047] In one embodiment of the present application, the silicon-based active material may be composed of silicon-based particles having 100 parts by weight of SiOx (x = 0) based on 100 parts by weight of the silicon-based active material.

[0048] In one embodiment of the present application, the silicon-based active material may contain metal impurities. In this case, the impurities are metals that can generally be contained in the silicon-based active material. Specifically, based on 100 parts by weight of the silicon-based active material, it may contain 0.1 part by weight or less.

[0049] In the case of silicon-based active materials, compared with the conventionally used graphite-based active materials, the capacity is significantly higher, and attempts to apply them are increasing. However, the volume expansion rate during charge and discharge is high, and it has been limited to cases such as mixing a small amount with graphite-based active materials.

[0050] Therefore, in the case of the present invention, in order to improve the capacity performance, while using only the silicon-based active material as the negative electrode active material, in order to solve the above problems, rather than adjusting the composition of the conductive material and the binder, the existing problems have been solved by adjusting the size or surface area of the crystal grains of the silicon-based active material itself.

[0051] In one embodiment of the present application, the size of the crystal grains of the silicon-based active material may be 200 nm or less.

[0052] In another embodiment, the size of the crystal grains of the silicon-based active material may be 200 nm or less, preferably 130 nm or less, more preferably 120 nm or less, still more preferably 100 nm or less, specifically 95 nm or less, and more specifically 91 nm or less. The size of the crystal grains of the silicon-based active material may have a range of 10 nm or more, preferably 15 nm or more.

[0053] The silicon-based active material has the size of the above-mentioned crystal grains, and the crystal grain size of the silicon-based active material can be adjusted by changing the process conditions in the manufacturing process. At this time, by satisfying the above range so that grain boundaries are widely distributed, when lithium ions are inserted, they will enter uniformly, and the stress applied when inserting lithium ions into silicon particles can be reduced, thereby relaxing the cracking of the particles. As a result, it will have the characteristic of being able to improve the life stability of the negative electrode. When the crystal grain size exceeds the above range, the intra-particle crystal grain system will be narrowly distributed. In this case, lithium ions in the particles will be inserted non-uniformly, the stress due to ion insertion will be large, and the particle cracking phenomenon will occur.

[0054] In one embodiment of the present application, the silicon-based active material includes a crystal structure having a crystal grain distribution of 1 nm or more and 200 nm or less, and provides a negative electrode active material in which the area ratio of the crystal structure is 5% or less based on the total area of the silicon-based active material.

[0055] In another embodiment, based on the total area of the silicon-based active material, the area ratio of the crystal structure may be 5% or less, 3% or less, and may be 0.1% or more.

[0056] That is, the silicon-based active material according to the present application has a crystal grain size of 200 nm or less, and the size of one crystal structure is formed small, and the above area ratio can be satisfied. Thereby, the distribution of grain boundaries can be widened, and the above-mentioned effects can be achieved.

[0057] In one embodiment of the present application, a negative electrode active material is provided in which the number of crystal structures included in the silicon-based active material is 20 or more.

[0058] In another embodiment, the number of crystal structures included in the silicon-based active material may be 20 or more, 30 or more, 35 or more, and may satisfy the range of 60 or less, 50 or less.

[0059] That is, as described above, when the silicon-based active material satisfies the grain size within the above range and the number of crystal structures within the above range, the strength of the silicon-based active material itself has an appropriate range, and when included in the electrode, it can impart flexibility and can efficiently suppress volume expansion.

[0060] In the present application, a crystal grain means crystal particles that are an aggregate of irregularly shaped microscopic sizes in a metal or material, and the crystal grain size can mean the diameter of the observed crystal grain particles. That is, in the present application, the crystal grain size means the size of a domain that shares the same crystal direction within the particle, and has a concept different from the particle size or particle diameter size that represents the size of a substance.

[0061] In one embodiment of the present application, the crystal grain size can be calculated as the FWHM (Full Width at Half Maximum) value through XRD analysis. Specifically, the method for calculating the crystal grain size can be understood from FIG. 3. In FIG. 3, the remaining values except for L are measured by XRD analysis of the silicon-based active material, and since the FWHM and the crystal grain size are inversely proportional through the Debye-Scherrer formula, the crystal grain size can be measured. At this time, the Debye-Scherrer formula is as shown in the following formula 1-1.

[0062] [Formula 1-1] FWHM = Kλ / LCosθ In the above formula 1-1, L represents the crystal grain size, K is a constant, θ is the Bragg angle, and λ represents the wavelength of X-ray.

[0063] Note that the shape of the crystal grains is diverse and can be measured three-dimensionally. Generally, the size of the crystal grains can be measured by the commonly used circle method or diameter measurement method, but it is not limited thereto.

[0064] The above diameter measurement method can be carried out by drawing 5 to 10 equilibrium lines each with a length of L mm on a micrograph of the target particles, counting the number of crystal grains z on the lines and averaging them. At this time, only those that are completely included are counted, excluding those that are merely touching. If the number of lines is P and the magnification is V, the average particle diameter can be calculated by the following formula 1-2.

[0065] [Formula 1-2] Dm=(L*P*10 3 ) / (zV)(um)

[0066] Also, the above circle method can be calculated by the following formula 1-3, which is a method of obtaining the average area of crystal grains by drawing a circle with a determined diameter on a micrograph of the target particles and then obtaining the average area of crystal grains based on the number of crystal grains inside the circle and the number of crystal grains on the boundary line.

[0067] [Formula 1-3] Fm=(Fk*10 6 ) / ((0.67n+z)V 2 )(um 2 ) In the above formula 1-3, Fm represents the average particle area, Fk represents the measured area on the photograph, z represents the number of particles inside the circle, n represents the number of particles on the arc, and V represents the magnification of the microscope.

[0068] In one embodiment of the present application, the negative electrode active material may contain a silicon-based active material with a specific surface area of 0.25 m 2 / g or more.

[0069] Also, in another embodiment, the silicon-based active material may have a specific surface area of 0.25 m 2 / g or more, preferably 0.28 m 2 / g or more, more preferably 0.30 m 2 / g or more, specifically 0.31 m 2 / g or more, more specifically 0.32 m 2 / g or more. The silicon-based active material may have a specific surface area of 3 m 2 / g or less, preferably 2.5 m 22.2 m / g or less, more preferably 2.2 m / g or less 2 It can satisfy the range of 2.2 m / g or less. The specific surface area can be measured according to DIN 66131 (using nitrogen).

[0070] The silicon-based active material has the above-mentioned specific surface area, and the size of the specific surface area of the silicon-based active material can be adjusted by changing the process conditions in the manufacturing process and the growth conditions of the silicon-based active material described later. That is, when manufacturing the negative electrode active material by the manufacturing method according to the present application, a rough surface results in a larger specific surface area compared to particles having the same particle size. At this time, satisfying the above range and having a high binding force with the binder can relieve the cracks of the electrode due to repeated charge and discharge cycles.

[0071] Also, when lithium ions are inserted, they can enter uniformly, and the stress generated when inserting lithium ions into silicon particles can be reduced, thereby relieving the cracking of the particles. As a result, it has the characteristic of improving the life stability of the negative electrode. When the specific surface area is less than the above range, even if the particle sizes are the same, the surface is smoothly formed, the binding force with the binder decreases, and electrode cracks occur. In this case, lithium ions in the particles are inserted non-uniformly, the stress due to ion insertion is large, and the particle cracking phenomenon occurs.

[0072] In one embodiment of the present application, the silicon-based active material provides a negative electrode active material that satisfies the range of the following formula 2-1. [Formula 2-1] X1 / Y1 ≤ 0.960 In the above formula 2-1, X1 is the actual projected area of the silicon-based active material, Y1 means the projected area of spherical particles in the same surroundings as the silicon-based active material.

[0073] The measurement of the formula 2-1 can be performed using a particle analyzer. Specifically, after dispersing the silicon-based active material according to the present application on a glass plate through air injection, the scattered silicon-based active material particles are photographed with a shadow image to measure the shapes of 10,000 silicon-based active material particles in the photograph. At this time, the formula 2-1 represents a value obtained by averaging over 10,000 particles. From the above image, the formula 2-1 according to the present application can be measured, and the formula 2-1 can be represented by the circularity of the silicon-based active material. The circularity may be represented by the formula [4π * actual area of the silicon-based active material / (boundary) 2 may also be represented.

[0074] In one embodiment of the present application, the circularity of the silicon-based active material may be, for example, 0.960 or less, for example, 0.957 or less. The circularity of the silicon-based active material may be 0.8 or more, for example, 0.9 or more, specifically 0.93 or more, more specifically 0.94 or more, for example, 0.941 or more.

[0075] In one embodiment of the present application, the silicon-based active material provides a negative electrode active material that satisfies the following formula 2-2. [Formula 2-2] X2 / Y2 ≦ 0.995 In the formula 2-2, Y2 is the actual perimeter of the silicon-based active material, X2 is the perimeter of the circumscribed figure of the silicon-based active material.

[0076] The measurement of the formula 2-2 can be performed using a particle analyzer. Specifically, after dispersing the silicon-based active material according to the present application on a glass plate through air injection, the scattered silicon-based active material particles are photographed with a shadow image to measure the shapes of 10,000 silicon-based active material particles in the photograph. At this time, the formula 2-2 represents a value obtained by averaging over 10,000 particles. From the above image, the formula 2-2 according to the present application can be measured, and the formula 2-2 can be represented as the convexity of the silicon-based active material.

[0077] In one embodiment of the present application, the range of X2 / Y2≤0.996, preferably X2 / Y2≤0.995 can be satisfied, and the range of 0.8≤X2 / Y2, preferably 0.9≤X2 / Y2, more preferably 0.95≤X2 / Y2, specifically 0.98≤X2 / Y2 can be satisfied.

[0078] The smaller the value of the formula 2-1 or the formula 2-2, the greater the roughness of the silicon-based active material can be meant. By using the silicon-based active material having the above range, the binding force with the binder is increased, and the electrodes can have the characteristic of relaxing cracks due to repeated charge and discharge cycles.

[0079] In one embodiment of the present application, the silicon-based active material may include silicon-based particles having a particle size distribution of 0.01 μm or more and 30 μm or less.

[0080] That the silicon-based active material includes silicon-based particles having a particle size distribution of 0.01 μm or more and 30 μm or less means that a large number of individual silicon-based particles having a particle size within the above range are included, and the number of silicon-based particles included is not limited.

[0081] The particle size of the silicon-based particles can be represented by its diameter in the case of a spherical shape. However, in the case of other non-spherical shapes, the particle size can be measured in comparison with the case of a spherical shape, and the particle size of individual silicon-based particles can generally be measured by a method used in the art.

[0082] On the one hand, the average particle size (D50 particle size) of the silicon-based active material of the present invention is 3 μm to 10 μm, specifically 4 μm to 8 μm, and more specifically may be 6 μm to 7 μm. When the average particle size is included in the above range, the specific surface area of the particles is included in an appropriate range, and the viscosity of the negative electrode slurry is formed in an appropriate range. As a result, the dispersion of the particles constituting the negative electrode slurry becomes smooth. Further, since the size of the silicon-based active material has a value equal to or greater than the lower limit value of the above range, the contact area between the silicon particles and the conductive material by the composite composed of the conductive material and the binder in the negative electrode slurry is excellent, and the possibility of the conductive network continuing is high, and the capacity retention rate increases. On the other hand, when the average particle size satisfies the above range, silicon particles that are too large are excluded, and the surface of the negative electrode is formed smoothly, thereby preventing the current density non-uniformity phenomenon during charge and discharge.

[0083] In one embodiment of the present application, the silicon-based active material has a generally characteristic BET specific surface area. The BET specific surface area of the silicon-based electrode active material is preferably 0.01 m 2 / g to 150.0 m 2 / g, more preferably 0.1 m 2 / g to 100.0 m 2 / g, particularly preferably 0.2 m 2 / g to 80.0 m 2 / g, most preferably 0.2 m 2 / g to 18.0 m 2 / g. The BET specific surface area is measured in accordance with DIN 66131 (using nitrogen).

[0084] In one embodiment of the present application, a negative electrode composition including the negative electrode active material; the negative electrode conductive material; and the negative electrode binder is provided.

[0085] In one embodiment of the present application, a negative electrode composition in which the silicon-based active material is 60 parts by weight or more based on 100 parts by weight of the negative electrode composition is provided.

[0086] In yet another embodiment, the silicon-based active material may contain 60 parts by weight or more, preferably 65 parts by weight or more, and more preferably 70 parts by weight or more, based on 100 parts by weight of the negative electrode composition, and may be 95 parts by weight or less, preferably 90 parts by weight or less, and more preferably 85 parts by weight or less.

[0087] The negative electrode composition according to the present application uses a negative electrode active material that satisfies a specific crystal grain size capable of suppressing the volume expansion rate during the charge and discharge process even when using a silicon-based active material with a significantly high capacity within the above range, and including the above range will not deteriorate the performance of the negative electrode, and it will have excellent output characteristics during charging and discharging.

[0088] Conventionally, it has been common to use only graphite-based compounds as the negative electrode active material. However, in recent years, as the demand for high-capacity batteries has increased, attempts have been increasing to mix and use silicon-based active materials to increase the capacity. However, in the case of silicon-based active materials, even if the characteristics of the silicon-based active material itself are adjusted as described above, there may be a problem that the volume rapidly expands during the charge / discharge process and damages the conductive path formed in the negative electrode active material layer.

[0089] Therefore, in one embodiment of the present application, the negative electrode conductive material may include at least one selected from the group consisting of a dot-shaped conductive material, a planar conductive material, and a linear conductive material.

[0090] In one embodiment of the present application, the dot-shaped conductive material can be used to improve the conductivity to the negative electrode, and means a dot-shaped or spherical conductive material having conductivity without inducing a chemical change. Specifically, the dot-shaped conductive material may be at least one selected from the group consisting of natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, conductive fiber, fluorocarbon, aluminum powder, nickel powder, zinc oxide, potassium titanate, titanium oxide, and polyphenylene derivatives, and preferably may contain carbon black in terms of realizing high conductivity and excellent dispersibility.

[0091] In one embodiment of the present application, the dot-shaped conductive material has a BET specific surface area of 40 m 2 / g or more and 70 m 2 / g or less, preferably 45 m 2 / g or more and 65 m 2 / g or less, more preferably 50 m 2 / g or more and 60 m 2 / g or less.

[0092] In one embodiment of the present application, the dot-shaped conductive material may satisfy a functional group content (Volatile matter) of 0.01% or more and 1% or less, preferably 0.01% or more and 0.3% or less, more preferably 0.01% or more and 0.1% or less.

[0093] In particular, when the functional group content of the dot-shaped conductive material satisfies the above range, functional groups exist on the surface of the dot-shaped conductive material, and when water is used as a solvent, the dot-shaped conductive material can be smoothly dispersed in the solvent. In particular, in the present invention, by using a specific silicon-based active material, the functional group content of the dot-shaped conductive material can be lowered, thereby having an excellent effect of improving dispersibility.

[0094] In one embodiment of the present application, it is characterized by including a dot-shaped conductive material having the functional group content within the above range together with a silicon-based active material, and the adjustment of the functional group content can be adjusted according to the degree of heat treatment of the dot-shaped conductive material.

[0095] In one embodiment of the present application, the particle size of the dot-shaped conductive material is 10 nm to 100 nm, preferably 20 nm to 90 nm, and more preferably 20 nm to 60 nm. In one embodiment of the present application, the conductive material may include a planar conductive material.

[0096] The planar conductive material can play a role in increasing the surface contact between silicon particles in the negative electrode to improve conductivity, and at the same time suppressing the interruption of the conductive path due to volume expansion. The planar conductive material can be expressed as a plate-shaped conductive material or a bulk-type conductive material.

[0097] In one embodiment of the present application, the planar conductive material can include at least one selected from the group consisting of plate-shaped graphite, graphene, graphene oxide, and graphite flakes, and preferably may be plate-shaped graphite.

[0098] In one embodiment of the present application, the average particle size (D50) of the planar conductive material is 2 μm to 7 μm, specifically 3 μm to 6 μm, and more specifically may be 3.5 μm to 5 μm. When the above range is satisfied, due to the sufficient particle size, dispersion is easy without causing an excessive increase in the viscosity of the negative electrode slurry. Therefore, when dispersing using the same equipment and time, the dispersion effect is excellent.

[0099] In one embodiment of the present application, the planar conductive material provides a negative electrode composition in which D10 is 0.5 μm or more and 2.0 μm or less, D50 is 2.5 μm or more and 3.5 μm or less, and D90 is 6.5 μm or more and 15.0 μm or less.

[0100] In one embodiment of the present application, the planar conductive material may be a high specific surface area planar conductive material with a high BET specific surface area; or a low specific surface area planar conductive material may be used.

[0101] In one embodiment of the present application, the high specific surface area planar conductive material; or the low specific surface area planar conductive material can be used without limitation as the planar conductive material. However, particularly for the planar conductive material according to the present application, the electrode performance may be affected to some extent by dispersion, and in some cases, it is particularly preferable to use a low specific surface area planar conductive material that does not cause problems in dispersion.

[0102] In one embodiment of the present application, the BET specific surface area of the planar conductive material may be 1 m 2 / g or more.

[0103] In another embodiment, the BET specific surface area of the planar conductive material may be 1 m 2 / g or more and 500 m 2 / g or less, preferably 5 m 2 / g or more and 300 m 2 / g or less, more preferably 5 m 2 / g or more and 250 m 2 / g or less. The planar conductive material according to the present application can use a high specific surface area planar conductive material; or a low specific surface area planar conductive material.

[0104] In another embodiment, the planar conductive material is a high specific surface area planar conductive material, and the BET specific surface area may satisfy the range of 50 m 2 / g or more and 500 m 2 / g or less, preferably 80 m 2 / g or more and 300 m 2 / g or less, more preferably 100 m 2 / g or more and 300 m 2 / g or less.

[0105] In another embodiment, the planar conductive material is a low specific surface area planar conductive material, and the BET specific surface area is 1 m 2 / g or more and 40 m 2 / g or less, preferably 5 m 2 / g or more and 30 m2 5 g or less, more preferably 5 m 2 / g or more and 25 m 2 / g or less.

[0106] As other conductive materials, linear conductive materials such as carbon nanotubes may be present. The carbon nanotubes may be bundle-type carbon nanotubes. The bundle-type carbon nanotubes may include a plurality of carbon nanotube unit bodies. Specifically, here, the "bundle type" refers to a secondary shape in the form of a bundle or a rope in which a plurality of carbon nanotube unit bodies are arranged side by side with substantially the same orientation of the longitudinal axis of the carbon nanotube unit body or are intertwined, unless otherwise specified. The carbon nanotube unit body has a cylindrical shape with a nanosize diameter of a graphite sheet and has an sp2 bonding structure. At this time, depending on the angle and structure by which the graphite sheet is wound, it can exhibit conductor or semiconductor characteristics. The bundle-type carbon nanotubes can be uniformly dispersed during the production of the negative electrode as compared with entangled-type carbon nanotubes, can smoothly form a conductive network inside the negative electrode, and can improve the conductivity of the negative electrode.

[0107] In one embodiment of the present application, the negative electrode conductive material provides a negative electrode composition that is 10 parts by weight or more and 40 parts by weight or less based on 100 parts by weight of the negative electrode composition.

[0108] In another embodiment, the negative electrode conductive material may include 0.1 part by weight or more and 40 parts by weight or less, preferably 0.2 part by weight or more and 30 parts by weight or less, more preferably 0.4 part by weight or more and 25 parts by weight or less, and most preferably 0.4 part by weight or more and 10 parts by weight or less based on 100 parts by weight of the negative electrode composition.

[0109] In one embodiment of the present application, the negative electrode conductive material provides a negative electrode composition including a planar conductive material and a linear conductive material.

[0110] In one embodiment of the present application, the negative electrode conductive material provides a negative electrode composition containing, based on 100 parts by weight of the negative electrode conductive material, 80 parts by weight or more and 99.9 parts by weight or less of the planar conductive material; and 0.1 parts by weight or more and 20 parts by weight or less of the linear conductive material.

[0111] In another embodiment, the negative electrode conductive material may contain, based on 100 parts by weight of the negative electrode conductive material, 80 parts by weight or more and 99.9 parts by weight or less of the planar conductive material, preferably 85 parts by weight or more to 99.9 parts by weight or less, and more preferably 95 parts by weight or more to 98 parts by weight or less.

[0112] In another embodiment, the negative electrode conductive material may contain, based on 100 parts by weight of the negative electrode conductive material, 0.1 parts by weight or more and 20 parts by weight or less of the linear conductive material, preferably 0.1 parts by weight or more to 15 parts by weight or less, and more preferably 0.2 parts by weight or more to 5 parts by weight or less.

[0113] In one embodiment of the present application, when the negative electrode conductive material contains a planar conductive material and a linear conductive material and satisfies the respective compositions and ratios, it does not significantly affect the life characteristics of existing lithium secondary batteries. In particular, when it contains a planar conductive material and a linear conductive material, there are many points where charging and discharging are possible, it has excellent output characteristics at a high C-rate, and the amount of high-temperature gas generation is reduced.

[0114] In one embodiment of the present application, the negative electrode conductive material may consist of a linear conductive material. In particular, when using a linear conductive material alone, it is possible to simplify the tortuosity of the electrode, which is a problem of silicon-based negative electrodes, and improve the electrode structure, thereby reducing the migration resistance of lithium ions in the electrode.

[0115] In one embodiment of the present application, when the negative electrode conductive material contains a linear conductive material alone, the negative electrode conductive material may contain, based on 100 parts by weight of the negative electrode composition, 0.1 parts by weight or more and 5 parts by weight or less, preferably 0.2 parts by weight or more to 3 parts by weight or less, and more preferably 0.4 parts by weight or more to 1 part by weight or less.

[0116] The negative electrode conductive material according to the present application has a completely different configuration from the positive electrode conductive material applied to the positive electrode. That is, in the case of the negative electrode conductive material according to the present application, it serves to capture the contacts between silicon-based active materials with a very large volume expansion of the electrode during charging and discharging. The positive electrode conductive material serves to impart partial conductivity while acting as a buffer with a buffering role when rolled, and the configuration and role of the negative electrode conductive material of the present invention are completely different.

[0117] In addition, the negative electrode conductive material according to the present application is applied to silicon-based active materials and has a completely different configuration from the conductive material applied to graphite-based active materials. That is, the conductive material used for an electrode having a graphite-based active material simply has particles smaller than the active material and thus has the characteristics of improving output characteristics and imparting partial conductivity, and the configuration and role are completely different from those of the negative electrode conductive material applied together with silicon-based active materials as in the present invention.

[0118] In one embodiment of the present application, the planar conductive material used as the above-described negative electrode conductive material has a structure and role different from those of the carbon-based active material generally used as the negative electrode active material. Specifically, the carbon-based active material used as the negative electrode active material may be artificial graphite or natural graphite, and means a material processed into a spherical or dot-like form to facilitate the storage and release of lithium ions.

[0119] On the other hand, the planar conductive material used as the negative electrode conductive material is a material having a planar or plate-like form and can be expressed as plate graphite. That is, it is a material included to maintain a conductive path within the negative electrode active material layer, and means a material for ensuring a planar conductive path inside the negative electrode active material layer rather than having a role in the storage and release of lithium.

[0120] That is, in the present application, the use of plate-shaped graphite as a conductive material means that it is processed into a planar or plate shape and used not as a material for storing or releasing lithium but as a substance for securing a conductive path. At this time, the negative electrode active material contained together has high capacity characteristics for storing and releasing lithium and plays a role of storing and releasing all lithium ions transmitted from the positive electrode.

[0121] On the other hand, in the present application, the use of a carbon-based active material as an active material means that it is processed into a dot shape or a spherical shape and used as a substance for storing or releasing lithium.

[0122] That is, in one embodiment of the present application, artificial graphite or natural graphite, which is a carbon-based active material, is in a dot shape and has a BET specific surface area of 0.1 m 2 / g or more and 4.5 m 2 / g or less. Further, the plate-shaped graphite, which is a planar conductive material, may have a planar BET specific surface area of 5 m 2 / g or more.

[0123] In one embodiment of the present application, the negative electrode binder may include at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluororubber, polyacrylic acid and substances in which their hydrogens are substituted with Li, Na, or Ca, etc., and may also include various copolymers thereof.

[0124] According to one embodiment of the present application, the negative electrode binder plays a role in suppressing the active material and the conductive material in order to prevent the twisting and structural deformation of the negative electrode structure during the volume expansion and relaxation of the silicon-based active material. As long as the above role is satisfied, any general binder can be applied. Specifically, an aqueous binder can be used, and more specifically, a PAM-based binder can be used.

[0125] In one embodiment of the present application, based on 100 parts by weight of the negative electrode composition, the negative electrode binder is 30 parts by weight or less, preferably 25 parts by weight or less, more preferably 20 parts by weight or less, and may be 5 parts by weight or more, 10 parts by weight or more.

[0126] Provided is a method for manufacturing a negative electrode active material, including the steps of chemically reacting a silane gas to deposit a silicon-based active material on the surface of a crystal nucleus; and obtaining the silicon-based active material deposited on the substrate, wherein the silicon-based active material satisfies the following formula 1.

[0127] [Formula 1] 45≦(X / Y)×100 In the above formula 1, Y represents the ratio of the (111) crystal plane in the silicon-based active material, X represents the ratio of the (220) crystal plane in the silicon-based active material.

[0128] According to an example, the silane gas may include at least one gas selected from monosilane, dichlorosilane, and trichlorosilane, and specifically may be trichlorosilane gas.

[0129] Provided is a method for manufacturing a negative electrode active material, wherein the step of chemically reacting the silane gas to deposit a silicon-based active material on the surface of a crystal nucleus is to form under high temperature conditions of 100°C or higher.

[0130] In one embodiment of the present application, the step of chemically reacting the silane gas to deposit a silicon-based active material on the crystal nucleus surface may be performed under a pressure condition of 10 Pa to 150 Pa. Due to such a low pressure, the silicon growth rate decreases, and thus small crystal grains can be formed. The step may be performed under a temperature condition of 100 °C or higher, specifically 500 °C or higher, preferably 800 °C or higher, more preferably 800 °C to 1300 °C, 800 °C to 2200 °C. This is a lower temperature than the conventional gas atomizing method that heats to 1600 °C or higher to melt Si.

[0131] In one embodiment of the present application, the step of chemically reacting the silane gas to deposit a silicon-based active material on the crystal nucleus surface; thereafter, the silicon-based active material may further include a step of growing through the formation of crystal nuclei.

[0132] At this time, the step of growing the silicon-based active material through the formation of crystal nuclei may be performed under a temperature condition of 800 °C or higher, preferably 800 °C to 1300 °C. This is a lower temperature than the conventional gas atomizing method that heats to 1600 °C or higher to melt Si. Also, the step of growing the silicon-based active material by crystal nucleus formation can be performed under a pressure of 100 Pa to 150 Pa. Due to such a low pressure, the silicon growth rate decreases, and thus small crystal grains and a specific surface area can be formed.

[0133] In one embodiment of the present application, the step of chemically reacting the silane gas to deposit a silicon-based active material on the crystal nucleus surface; thereafter, the silicon-based active material further includes a step of growing through the formation of crystal nuclei, and the step of growing the silicon-based active material through crystal nucleus formation includes a step of forming crystal nuclei at a temperature of 800 °C or higher for 1 hour to 24 hours, and a method for manufacturing a negative electrode active material is provided.

[0134] By the manufacturing method as described above, a silicon-based active material with the distribution of Formula 1 in the particles adjusted can be manufactured.

[0135] Conventionally, silicon blocks have been produced by pulverizing them with physical force. When manufacturing in this way, the size of the crystal grains generally exceeds the 200 nm range, and the surface is smooth and the surface area has a value of less than 0.25 m 2 / g. When simply manufacturing a silicon-based active material by a conventional method, there is a drawback that the size of the surface area cannot be controlled and it is difficult to ensure the life stability of the negative electrode.

[0136] However, the method for manufacturing a negative electrode active material according to the present application can form silicon particles including a step of growing the silicon-based active material through crystal nucleation after silanizing silicon blocks through a chemical reaction under specific process conditions as described above. As a result, it has the characteristics of satisfying the surface area size and crystal grain size according to the present application and being able to control the crystal grain orientation.

[0137] In one embodiment of the present application, a negative electrode for a lithium secondary battery is provided, which includes a negative electrode current collector layer; and a negative electrode active material layer including the negative electrode composition according to the present application or a cured product thereof formed on one or both surfaces of the negative electrode current collector layer.

[0138] FIG. 1 is a diagram showing a laminated structure of a negative electrode for a lithium secondary battery according to one embodiment of the present application. Specifically, a negative electrode 100 for a lithium secondary battery including a negative electrode active material layer 20 on one surface of a negative electrode current collector layer 10 can be confirmed. FIG. 1 shows that the negative electrode active material layer is formed on one surface, but it may be included on both surfaces of the negative electrode current collector layer.

[0139] In one embodiment of the present application, the negative electrode for a lithium secondary battery may be formed by applying and drying a negative electrode slurry including the negative electrode composition on one or both surfaces of the negative electrode current collector layer.

[0140] At this time, the negative electrode slurry may include the aforementioned negative electrode composition; and a slurry solvent.

[0141] In one embodiment of the present application, the solid content of the negative electrode slurry may satisfy 5% or more and 40% or less.

[0142] In another embodiment, the solid content of the negative electrode slurry may satisfy a range of 5% or more and 40% or less, preferably 7% or more and 35% or less, and more preferably 10% or more and 30% or less.

[0143] The solid content of the negative electrode slurry can mean the content of the negative electrode composition contained in the negative electrode slurry, and can mean the content of the negative electrode composition based on 100 parts by weight of the negative electrode slurry.

[0144] When the solid content of the negative electrode slurry satisfies the above range, the viscosity during the formation of the negative electrode active material layer is appropriate, and it has the characteristic that the particle aggregation phenomenon of the negative electrode composition can be minimized and the negative electrode active material layer can be efficiently formed.

[0145] In one embodiment of the present application, the slurry solvent can be used without limitation as long as it can dissolve the negative electrode composition. Specifically, water or NMP can be used.

[0146] In one embodiment of the present application, the negative electrode current collector layer generally has a thickness of 1 μm to 100 μm. Such a negative electrode current collector layer is not particularly limited as long as it has high conductivity without inducing a chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, those surface-treated with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, etc. can be used. Also, fine irregularities can be formed on the surface to strengthen the binding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams, non-woven bodies, etc.

[0147] In one embodiment of the present application, there is provided a negative electrode for a lithium secondary battery, wherein the thickness of the negative electrode current collector layer is 1 μm or more and 100 μm or less, and the thickness of the negative electrode active material layer is 20 μm or more and 500 μm or less.

[0148] However, the thickness can be variously deformed according to the type and use of the negative electrode used, and is not limited thereto.

[0149] In one embodiment of the present application, the porosity of the negative electrode active material layer may satisfy the range of 10% or more and 60% or less.

[0150] In another embodiment, the porosity of the negative electrode active material layer may satisfy the range of 10% or more and 60% or less, preferably 20% or more and 50% or less, and more preferably 30% or more and 45% or less.

[0151] The porosity varies according to the composition and content of the silicon-based active material, conductive material, and binder contained in the negative electrode active material layer. In particular, by including the silicon-based active material and conductive material according to the present application in specific compositions and content parts, the above range is satisfied, and thereby, the electric conductivity and resistance in the electrode have an appropriate range.

[0152] In one embodiment of the present application, there is provided a lithium secondary battery including a positive electrode, a negative electrode for a lithium secondary battery according to the present application, a separator provided between the positive electrode and the negative electrode, and an electrolyte.

[0153] FIG. 2 is a diagram showing a laminated structure of a lithium secondary battery according to an embodiment of the present application. Specifically, a negative electrode 100 for a lithium secondary battery including a negative electrode active material layer 20 can be confirmed on one surface of a negative electrode current collector layer 10, and a positive electrode 200 for a lithium secondary battery including a positive electrode active material layer 40 can be confirmed on one surface of a positive electrode current collector layer 50. It shows that the negative electrode 100 for a lithium secondary battery and the positive electrode 200 for a lithium secondary battery are laminated with a separator 30 interposed therebetween.

[0154] The secondary battery according to an embodiment of the present specification may particularly include the negative electrode for a lithium secondary battery described above. Specifically, the secondary battery may include a negative electrode, a positive electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, and the negative electrode is the same as the negative electrode described above. Since the negative electrode has been described above, a specific description thereof will be omitted.

[0155] The positive electrode may include a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector and containing the positive electrode active material.

[0156] In the positive electrode, the positive electrode current collector is not particularly limited as long as it has conductivity without inducing a chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, fired carbon, or a material obtained by surface treatment with carbon, nickel, titanium, silver, etc. on the surface of aluminum or stainless steel can be used. Further, the positive electrode current collector can usually have a thickness of 3 μm to 500 μm, and fine irregularities can be formed on the surface of the current collector to increase the adhesion of the positive electrode active material. For example, it may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric body, etc.

[0157] The positive electrode active material may be a commonly used positive electrode active material. Specifically, the positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; the chemical formula Li 1+c1 Mn 2-c1 O4 (0 ≦ c1 ≦ 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; the chemical formula LiNi 1-c2 M c2 O2 (where M is at least any one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01 ≦ c2 ≦ 0.6) represented by Ni-site type lithium nickel oxide; the chemical formula LiMn2-c3 M c3 O2 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfies 0.01 ≦ c3 ≦ 0.6) or Li2Mn3MO8 (where M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn).); lithium manganese composite oxides represented by, for example, LiMn2O4 in which part of the Li in the chemical formula is substituted with alkaline earth metal ions, but not limited thereto. The positive electrode may be metallic lithium (Li-metal).

[0158] In one embodiment of the present application, the positive electrode active material includes a lithium composite transition metal compound containing nickel (Ni), cobalt (Co), and manganese (Mn). The lithium composite transition metal compound includes single particles or secondary particles, and the average particle diameter (D50) of the single particles may be 1 μm or more.

[0159] For example, the average particle diameter (D50) of the single particles may be 1 μm or more and 12 μm or less, 1 μm or more and 8 μm or less, 1 μm or more and 6 μm or less, more than 1 μm and 12 μm or less, more than 1 μm and 8 μm or less, or 1 μm and 6 μm or less.

[0160] The single particles can have excellent particle strength even when formed with a small particle diameter having an average particle diameter (D50) of 1 μm or more and 12 μm or less. For example, the single particles can have a particle strength of 100 MPa to 300 MPa during rolling with a force of 650 kgf / cm 2 Thereby, even when the single particles are rolled with a strong force of 650 kgf / cm 2 the phenomenon of an increase in fine particles in the electrode due to particle cracking is alleviated, and thereby the life characteristics of the battery are improved.

[0161] The single particles can be manufactured by mixing a transition metal precursor and a lithium raw material and firing them. The secondary particles can be manufactured by a method different from that of the single particles, and their composition may be the same as or different from that of the single particles.

[0162] The method for forming the single particles is not particularly limited, but generally, it can be formed by increasing the firing temperature to overfire. It can be manufactured by methods such as using additives such as grain growth promoters useful for overfiring or changing the starting materials.

[0163] For example, the firing is performed at a temperature capable of forming single particles. To form this, firing must be performed at a temperature higher than that during the production of secondary particles. For example, when the precursor composition is the same, firing must be performed at a temperature about 30°C to 100°C higher than that during the production of secondary particles. The firing temperature for forming the single particles can vary depending on the metal composition in the precursor. For example, when forming a high-content nickel (High-Ni) NCM-based lithium composite transition metal oxide with a nickel (Ni) content of 80 mol% or more into single particles, the firing temperature may be about 700°C to 1000°C, preferably about 800°C to 950°C. When the firing temperature satisfies the above range, a cathode active material containing single particles with excellent electrochemical properties can be manufactured. When the firing temperature is less than 790°C, a cathode active material containing a secondary particle-like lithium composite transition metal compound can be manufactured. When it exceeds 950°C, overfiring occurs, the layered crystal structure cannot be well formed, and the electrochemical properties may deteriorate.

[0164] In this specification, the single particles are terms used to distinguish from the conventional secondary particles formed by aggregation of dozens to hundreds of primary particles, and are concepts including single particles composed of one primary particle and pseudo-single particle forms that are aggregates of 30 or fewer primary particles.

[0165] Specifically, the single particles in the present invention may be in the form of single particles composed of one primary particle or pseudo-single particles that are aggregates of 30 or fewer primary particles, and the secondary particles may be in the form of aggregates of hundreds of primary particles.

[0166] In one embodiment of the present application, the lithium composite transition metal compound as the positive electrode active material further includes secondary particles, and the average particle size (D50) of the single particles is smaller than the average particle size (D50) of the secondary particles.

[0167] In the present invention, the single particle may be in the form of a single particle composed of one primary particle or a pseudo-single particle which is an aggregate of 30 or fewer primary particles, and the secondary particle may be in the form of an aggregate of hundreds of primary particles.

[0168] The aforementioned lithium composite transition metal compound may further include secondary particles. The secondary particle means a form formed by aggregation of primary particles, and can be distinguished from the concept of single particles including a single primary particle, a single particle, or a pseudo-single particle which is an aggregate of 30 or fewer primary particles.

[0169] The particle size D50 of the secondary particles may be 1 μm to 20 μm, 2 μm to 17 μm, preferably 3 μm to 15 μm. The specific surface area (BET) of the secondary particles is 0.05 m 2 / g to 10 m 2 / g, preferably 0.1 m 2 / g to 1 m 2 / g, more preferably 0.3 m 2 / g to 0.8 m 2 / g.

[0170] In a further embodiment of the present application, the secondary particles are aggregates of primary particles, and the average particle size (D50) of the primary particles is 0.5 μm to 3 μm. Specifically, the secondary particles may be in the form of an aggregate of hundreds of primary particles, and the average particle size (D50) of the primary particles may be 0.6 μm to 2.8 μm, 0.8 μm to 2.5 μm, or 0.8 μm to 1.5 μm.

[0171] When the average particle size (D50) of the primary particles satisfies the above range, single-particle cathode active materials with excellent electrochemical properties can be formed. If the average particle size (D50) of the primary particles is too small, the number of aggregated primary particles forming the lithium nickel-based oxide particles increases, and the effect of suppressing particle cracking during rolling decreases. If the average particle size (D50) of the primary particles is too large, the lithium diffusion path inside the primary particles becomes longer, the resistance increases, and the output characteristics may decrease.

[0172] According to a further embodiment of the present application, the average particle size (D50) of the single particles is characterized by being smaller than the average particle size (D50) of the secondary particles. Thereby, even if the single particles are formed with a small particle size, their particle strength can be excellent, whereby the phenomenon of an increase in fine particles in the electrode due to particle cracking is alleviated, and the life characteristics of the battery can be improved.

[0173] In one embodiment of the present application, the average particle size (D50) of the single particles is 1 μm to 18 μm smaller than the average particle size (D50) of the secondary particles.

[0174] For example, the average particle size (D50) of the single particles can be 1 μm to 16 μm smaller than the average particle size (D50) of the secondary particles, 1.5 μm to 15 μm smaller, or 2 μm to 14 μm smaller.

[0175] When the average particle size (D50) of the single particles is smaller than the average particle size (D50) of the secondary particles, for example, when satisfying the above range, even if the single particles are formed with a small particle size, their particle strength can be excellent, whereby the phenomenon of an increase in fine particles in the electrode due to particle cracking is alleviated, and there are effects of improving the life characteristics and energy density of the battery.

[0176] According to a further embodiment of the present application, the single particles are contained in an amount of 15 parts by weight to 100 parts by weight based on 100 parts by weight of the cathode active material. The single particles may be contained in an amount of 20 parts by weight to 100 parts by weight, or 30 parts by weight to 100 parts by weight based on 100 parts by weight of the cathode active material.

[0177] For example, the single particles may be included in an amount of 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more, 40 parts by weight or more, or 45 parts by weight or more with respect to 100 parts by weight of the positive electrode active material. The single particles may be included in an amount of 100 parts by weight or less with respect to 100 parts by weight of the positive electrode active material.

[0178] When the single particles within the above range are included, excellent battery characteristics can be exhibited in combination with the negative electrode material described above. In particular, when the single particles are 15 parts by weight or more, the phenomenon of an increase in fine particles in the electrode due to particle cracking during the rolling process after electrode fabrication can be alleviated, and thereby the life characteristics of the battery can be improved.

[0179] In one embodiment of the present application, the lithium composite transition metal compound may further include secondary particles, and the secondary particles may be 85 parts by weight or less with respect to 100 parts by weight of the positive electrode active material. The secondary particles may be 80 parts by weight or less, 75 parts by weight or less, or 70 parts by weight or less with respect to 100 parts by weight of the positive electrode active material. The secondary particles may be 0 parts by weight or more with respect to 100 parts by weight of the positive electrode active material.

[0180] When the above range is satisfied, the above-described effects due to the presence of the single particle positive electrode active material can be maximized. When the positive electrode active material includes secondary particles, the components thereof may be the same as those exemplified by the above-described single particle positive electrode active material, or may be different components, and may mean a form in which the single particle form is aggregated.

[0181] In one embodiment of the present application, the positive electrode active material in 100 parts by weight of the positive electrode active material layer may be included in an amount of 80 parts by weight or more and 99.9 parts by weight or less, preferably 90 parts by weight or more and 99.9 parts by weight or less, more preferably 95 parts by weight or more and 99.9 parts by weight or less, and even more preferably 98 parts by weight or more and 99.9 parts by weight or less.

[0182] The positive electrode active material layer may include a positive electrode conductive material and a positive electrode binder together with the positive electrode active material described above.

[0183] At this time, the positive electrode conductive material is used to impart conductivity to the electrode, and in the battery to be configured, it can be used without particular limitation as long as it has electron conductivity without causing a chemical change. Specific examples include graphite such as natural graphite and artificial graphite; carbon-based substances such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders or metal fibers 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. Among these, one kind alone or a mixture of two or more kinds can be used.

[0184] In addition, the positive electrode binder plays a role in improving the adhesion between the positive electrode active material particles and the adhesive force between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof. Among these, one kind alone or a mixture of two or more kinds may be used.

[0185] The separation membrane is used to separate the negative electrode and the positive electrode and provide a migration path for lithium ions. Generally, any material can be used without particular limitation as long as it is normally used as a separation membrane in a secondary battery. In particular, it is preferably low in resistance to the ion migration of the electrolyte while being excellent in the ability to hold the electrolyte solution. Specifically, a porous polymer film, for example, a porous polymer film made of polyolefin-based polymers such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a laminate structure of two or more layers thereof may be used. Also, a normal porous non-woven fabric, for example, a non-woven fabric made of high-melting glass fibers, polyethylene terephthalate fibers, etc. may be used. Further, in order to ensure heat resistance or mechanical strength, a coated separation membrane containing a ceramic component or a polymer substance can also be used, and it may be selectively used in a single-layer or multi-layer structure.

[0186] Examples of the electrolyte include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries. Specifically, the electrolyte may contain a non-aqueous organic solvent and a metal salt.

[0187] Examples of the non-aqueous organic solvent include aprotic organic solvents such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, methyl propionate, ethyl propionate, etc. may be used.

[0188] In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates among the carbonate-based organic solvents, are high-viscosity organic solvents with high dielectric constants and can dissociate lithium salts well, so they are preferably used. When such cyclic carbonates are mixed with chain carbonates such as dimethyl carbonate and diethyl carbonate having low viscosity and low dielectric constant in an appropriate ratio and used, an electrolyte having high electrical conductivity can be produced and can be more preferably used.

[0189] As the metal salt, a lithium salt can be used. The lithium salt is a substance that is easily dissolved in the non-aqueous electrolyte. For example, as the anion of the lithium salt, F - , Cl - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3- 、(CF3SO2)2N - 、(FSO2)2N - 、CF3CF2(CF3)2CO - 、(CF3SO2)2CH - 、(SF5)3C - 、(CF3SO2)3C - 、CF3(CF2)7SO3 - 、CF3CO2 - 、CH3CO2 - 、SCN - and (CF3CF2SO2)2N - One or more selected from the group consisting of can be used.

[0190] In addition to the electrolyte components, the electrolyte may further contain one or more additives such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethyl phosphite, triethanolamine, cyclic ethers, ethylenediamine, n-glyme, triamide hexaline, nitrobenzene derivatives, sulfur, quinoneimine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol or aluminum trichloride for the purpose of improving the life characteristics of the battery, suppressing the decrease in battery capacity, improving the discharge capacity of the battery, etc.

[0191] One embodiment of the present invention provides a battery module including the secondary battery as a unit cell and a battery pack including the same. Since the battery module and the battery pack include the secondary battery having high capacity, high rate characteristics and cycle characteristics, they can be used as a power source for medium and large-sized devices selected from the group consisting of electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles and power storage systems.

Examples

[0192] Hereinafter, preferred embodiments are presented to facilitate understanding of the present invention. However, these embodiments are for illustrative purposes only, and it is obvious to those skilled in the art that various changes and modifications can be made within the scope of this description and the scope of the technical idea. It goes without saying that such variations and modifications belong to the scope of the appended claims.

[0193] <Production Example> <Production of Anode Active Materials for Examples 1 to 5> By the chemical reaction of silane gas, a silicon-deposited active material was formed on the crystal nuclei in the reactor, and the growth time in Table 1 below was adjusted to produce a silicon-based active material. The range of Related Formula 1 is described in Table 1 below.

[0194] <Production of Anode Active Material for Comparative Example 1> The silicon core provided in the metal reactor (reduction furnace) was heated by energization, and a gas mixture of purified high-purity monosilane (SiH4) gas vapor and purified hydrogen was passed through. As a result, polycrystalline silicon was deposited on the surface of the silicon core, and a polycrystalline silicon mass in the shape of a thick rod was produced. Then, a silicon-based active material was produced by pulverization and classification.

[0195] <Production of Anode Active Material for Comparative Example 2> In Example 1 above, instead of using crystal nuclei, a material obtained by pulverizing a material in which silicon was grown on a substrate was used, and it was vapor-deposited in the substrate in a state where gas was flowing instead of using a reactor in which crystal nuclei were placed and flowed.

[0196]

Table 1

[0197] In Table 1 above, the spherical silicon-based active material means an active material having a circularity of 0.9 or more after measuring the sphericity of each particle, and the parts by weight of the spherical silicon-based active material mean the parts by weight in Table 1 above based on 100 parts by weight of the total silicon-based active material.

[0198] <Manufacture of Negative Electrode> A negative electrode slurry was produced by adding a negative electrode active material containing the silicon-based active material, a first conductive material, a second conductive material, and polyacrylamide as a binder in a weight ratio of 80:9.6:0.4:10 to distilled water as a solvent for forming the negative electrode slurry (solid content concentration: 25% by weight).

[0199] Specifically, the first conductive material was plate-shaped graphite (specific surface area: 17 m 2 / g, average particle size (D50): 3.5 μm), and the second conductive material was SWCNT.

[0200] As a specific mixing method, the first conductive material, the second conductive material, the binder, and water were dispersed at 2500 rpm for 30 min using a homomixer, then the silicon-based active material was added, and then dispersed at 2500 rpm for 30 min to prepare a negative electrode slurry.

[0201] The negative electrode slurry was coated on both sides of a copper current collector (thickness: 8 μm) as a negative electrode current collector layer at a loading amount of 85 mg / 25 cm 2 and rolled (roll press), and dried in a vacuum oven at 130 °C for 10 h to form a negative electrode active material layer (thickness: 33 μm), which was used as the negative electrode (negative electrode thickness: 41 μm, negative electrode porosity: 40.0%).

[0202] <Manufacture of Secondary Battery> As a positive electrode active material, LiNi 0.6 Co 0.2 Mn 0.2 O2 (average particle size (D50): 15 μm), carbon black (product name: Super C65, manufacturer: Timcal) as a conductive material, and polyvinylidene fluoride (PVdF) as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent for forming the positive electrode slurry in a weight ratio of 97:1.5:1.5 to produce a positive electrode slurry (solid content concentration: 78% by weight).

[0203] The positive electrode slurry was coated on both sides of an aluminum current collector (thickness: 12 μm) as a positive electrode current collector at 537 mg / 25 cm 2Coated with the loading amount of , roll-pressed, and dried in a vacuum oven at 130 °C for 10 hours to form a positive electrode active material layer (thickness: 65 μm) to fabricate a positive electrode (thickness of the positive electrode: 77 μm, porosity 26%).

[0204] An electrolyte was injected between the positive electrode and the negative electrodes of the examples and comparative examples through a polyethylene separator to fabricate a lithium secondary battery.

[0205] The electrolyte was a mixture of fluoroethylene carbonate (FEC) and diethyl carbonate (DEC) in a volume ratio of 10:90, with vinylene carbonate added at 3% by weight based on the total weight of the electrolyte, and LiPF6 added as a lithium salt at a concentration of 1 M.

[0206] Experimental Example 1: Monocell Life Evaluation The secondary batteries including the negative electrodes manufactured in the examples and comparative examples were evaluated for their lifespan using an electrochemical charge-discharge device, and the capacity retention rate was evaluated. The secondary batteries were subjected to an In-situ cycle test at 4.2 - 3.0 V, 1C / 0.5C, and the capacity maintenance rate was measured by charging / discharging at 0.33C / 0.33C (4.2 - 3.0 V) every 50 cycles during the test. The results are shown in Table 2. Capacity retention rate (%) = {(Discharge capacity at the Nth cycle) / (Discharge capacity at the first cycle)} × 100

[0207]

Table 2

[0208] Experimental Example 2: Evaluation of @SOC50 2.5C Discharge Resistance Increase Rate (After 200 Cycles) During the test in Experimental Example 1, after measuring the capacity retention rate by charging / discharging at 0.33C / 0.33C (4.2 - 3.0 V) every 50 cycles, the battery was discharged at 2.5C pulse at SOC50 to measure the resistance, and the resistance increase rate was compared and analyzed. Regarding the evaluation of the resistance increase rate, the data at 200 cycles were calculated respectively, and the results were as shown in Table 3 below.

[0209] [Table 3]

[0210] As can be confirmed from Tables 2 and 3 above, in the case of Examples 1 to 5 in which the crystal planes according to the present application were adjusted, it was confirmed that they were superior in terms of life evaluation and resistance increase rate compared to Comparative Examples 1 and 2.

[0211] This is because, by controlling the crystal grain orientation distribution that satisfies the range of Formula 1, that is, when the proportion of the (111) crystal plane is relatively large as in the prior art, the (111) crystal plane has a lower lithium mobility than the (220) crystal plane, and lithium cannot enter and exit uniformly during the insertion and desorption reaction of lithium. However, it was confirmed that the silicon-based active material according to the present application contains a large proportion of the (220) crystal plane differently from the prior art, lithium enters and exits uniformly in the insertion and desorption reaction of lithium, and the phenomenon of silicon cracking on the electrode surface can be alleviated, thereby strengthening the life characteristics of the electrode.

[0212] For reference, in the case of Comparative Example 1, the silicon core provided in the metal reactor (reduction furnace) was heated by energization, and a gas mixture of the vapor of highly purified monosilane (SiH4) gas purified therefrom and purified hydrogen was passed therethrough to deposit polycrystalline silicon on the surface of the silicon core. Thereafter, through the pulverization process, the value of Formula 1 (I(220) / I(111)×100) became relatively low, and it was confirmed that it was not as good as the examples in terms of life evaluation and resistance increase rate evaluation.

[0213] In the case of Comparative Example 2, it is a material obtained by pulverizing a material in which silicon was grown on a substrate, and it is a material vapor-deposited in the substrate in a state where a gas is passed instead of a reactor in which crystal nuclei are introduced and flow. Also in this case, it was confirmed that the value of Formula 1 was formed low in the same manner as in Comparative Example 1, and it was not as good as the examples in terms of life evaluation and resistance increase rate evaluation.

Explanation of Reference Signs

[0214] 10 ··· Negative electrode current collector layer 20 ··· Negative electrode active material layer 30 ··· Separator 40 ··· Positive electrode active material layer 50 ··· Positive electrode current collector layer 100 ··· Negative electrode for lithium secondary battery 200 ··· Positive electrode for lithium secondary battery

Claims

1. It contains a silicon-based active material including a (220) crystal plane and a (111) crystal plane, The silicon-based active material satisfies the following formula 1, The silicon-based active material includes at least one selected from the group consisting of SiOₓ (x = 0) and SiOₓ (0 < x < 2), and based on 100 parts by weight of the silicon-based active material, it contains 70 parts by weight or more of the SiOₓ (x = 0). Anode active material: [Formula 1] 45 ≤ (X / Y) × 100 In the above formula 1, Y means the ratio of the (111) crystal plane in the silicon-based active material, X means the ratio of the (220) crystal plane in the silicon-based active material.

2. The silicon-based active material includes at least one selected from the group consisting of a spherical silicon-based active material and a plate-shaped silicon-based active material, The anode active material according to claim 1, which contains 80 parts by weight or more of the spherical silicon-based active material based on 100 parts by weight of the silicon-based active material.

3. The anode active material according to claim 1, wherein the D50 particle size of the silicon-based active material is 3 μm or more and 10 μm or less.

4. The anode active material according to claim 1, wherein the crystal grain size of the silicon-based active material is 200 nm or less.

5. Chemically reacting silane gas to deposit a silicon-based active material on the crystal nucleus surface, and Obtaining the deposited silicon-based active material, A method for manufacturing an anode active material, comprising: The silicon-based active material satisfies the following formula 1. The method for manufacturing an anode active material according to any one of claims 1 to 4: [Formula 1] 45 ≤ (X / Y) × 100 In the above formula 1, Y represents the ratio of the (111) crystal plane in the silicon-based active material, X represents the ratio of the (220) crystal plane in the silicon-based active material.

6. The method for manufacturing a negative electrode active material according to claim 5, wherein the silane gas contains at least one gas selected from monosilane, dichlorosilane, and trichlorosilane.

7. The method for manufacturing a negative electrode active material according to claim 5, wherein the step of chemically reacting the silane gas to deposit a silicon-based active material on the crystal nucleus surface is formed under high-temperature conditions of 100 °C or higher.

8. After the step of chemically reacting the silane gas to deposit a silicon-based active material on the crystal nucleus surface, The method further includes a step of growing the silicon-based active material through crystal nucleus generation, The method for manufacturing a negative electrode active material according to claim 5, wherein the step of growing the silicon-based active material through crystal nucleus generation includes a step of generating crystal nuclei at a temperature of 800 °C or higher for 1 hour to 24 hours.

9. A negative electrode composition including the negative electrode active material, the negative electrode conductive material, and the negative electrode binder according to any one of claims 1 to 4.

10. The negative electrode composition according to claim 9, wherein the negative electrode active material is 60 parts by weight or more based on 100 parts by weight of the negative electrode composition.

11. The negative electrode composition according to claim 9, wherein the negative electrode conductive material includes at least one selected from the group consisting of a dot-shaped conductive material, a planar conductive material, and a linear conductive material.

12. Including a negative electrode current collector layer and a negative electrode active material layer provided on one or both sides of the negative electrode current collector layer, The negative electrode for a lithium secondary battery, wherein the negative electrode active material layer includes the negative electrode composition according to claim 9 or a cured product thereof.

13. The thickness of the negative electrode current collector layer is 1 μm or more and 100 μm or less, The thickness of the negative electrode active material layer is 20 μm or more and 500 μm or less. The negative electrode for a lithium secondary battery according to claim 12.

14. A positive electrode, The negative electrode for a lithium secondary battery according to claim 12, A separator provided between the positive electrode and the negative electrode, and An electrolyte, A lithium secondary battery comprising the same.

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