Binder composition, and negative electrode for secondary battery and lithium secondary battery comprising binder composition

Abstract

The present invention provides a binder composition, and a negative electrode for a secondary battery, and a lithium secondary battery, each comprising the binder composition. The binder composition of the present invention includes: a first binder resin; a second binder resin; and water, wherein the binder composition may include: lithium-substituted polyacrylic acid having a weight average molecular weight (Mw) of 300,000-1,500,000 g / mol as the first binder resin; and lithium-substituted carboxymethyl cellulose having a weight average molecular weight (Mw) of 300,000-1,500,000 g / mol as the second binder resin.

Description

Binder composition, negative electrode for secondary battery and lithium secondary battery including the binder composition Cross-citation with related application(s) This application claims the benefit of priority to Korean Patent Application No. 10-2023-0103197, filed August 7, 2023, and Korean Patent Application No. 10-2024-0102770, filed August 1, 2024, the entire contents of which are incorporated herein by reference. The present invention relates to a binder composition, an anode for a secondary battery including the binder composition, and a lithium secondary battery, and more specifically, to a binder composition capable of suppressing volume expansion of an anode, an anode for a secondary battery including the binder composition, and a lithium secondary battery including the same and thereby having improved cycle characteristics. As technological developments and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium secondary batteries, with their high energy density, high voltage, and long cycle life, are commercialized and widely used. A lithium secondary battery includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode to separate them, and an electrolyte that electrochemically communicates with the positive electrode and the negative electrode. These lithium secondary batteries are typically manufactured using a lithium-intercalated compound, such as LiCoO2 or LiMn2O4, for the positive electrode and a carbon-based material, such as a non-lithium-intercalated material, for the negative electrode. When charging, lithium ions inserted into the positive electrode move to the negative electrode through the electrolyte, and when discharging, lithium ions move from the negative electrode to the positive electrode again, operating. Meanwhile, carbon-based materials like graphite, used as cathode materials, exhibit excellent stability and reversibility, but are limited in terms of capacity. Therefore, to address the high-capacity demands of applications such as EVs, active research is currently underway to utilize silicon (Si), a non-carbon material with high theoretical capacity. The above silicon (Si) material is abundant in nature and its theoretical specific capacity is 4,200 mAh / g, which is higher than that of a commercial graphite anode (372 mAhg). -1 ) is about ten times higher than that of silicon, and is attracting great attention as a next-generation cathode material for high-energy-density lithium-ion batteries. In addition, silicon-based materials have the advantages of being low-cost, non-toxic, environmentally friendly, and having a low operating voltage (<0.5 V vs. Li + / Li). However, silicon-based materials have a high initial irreversible capacity, which leads to severe lithium depletion, and thus have a low initial efficiency compared to the carbon-based negative electrode active material. In particular, the silicon-based materials experience rapid volume expansion (≥300%) due to changes in their crystal structure caused by the insertion and deintercalation of lithium ions during charging and discharging, which can cause local short-circuiting (isolation) or damage to the electrode, increasing resistance and causing rapid capacity reduction in the secondary battery, making it difficult to secure stable output characteristics and cycle characteristics. Therefore, in order to apply silicon-based materials as negative electrode active materials, research and development is required to solve the problem of deterioration due to volume expansion of silicon-based materials and secure durability and charge / discharge efficiency. The present invention is intended to solve the above problems, and provides a binder composition having a specific composition, and by using the binder composition in combination with a silicon-based negative electrode active material, the problem of deterioration due to volume expansion of the silicon-based negative electrode active material can be improved, and at the same time, excellent electrode adhesion can be secured, thereby providing a negative electrode for a secondary battery having excellent durability and charge / discharge efficiency. In addition, the present invention aims to provide a lithium secondary battery having improved output characteristics and cycle characteristics by including the negative electrode for a secondary battery. [1] The present invention comprises a first binder resin, a second binder resin and water, A binder composition is provided, which includes a lithium-substituted polyacrylic acid having a weight average molecular weight (Mw) of 300,000 g / mol to 1,500,000 g / mol as the first binder resin, and a lithium-substituted carboxymethyl cellulose having a weight average molecular weight (Mw) of 50,000 g / mol to 1,000,000 g / mol as the second binder resin. [2] The present invention provides a binder composition in which, in the above [1], the weight average molecular weight (Mw) of the first binder resin is 500,000 to 1,500,000 g / mol. [3] The present invention provides a binder composition in which the weight average molecular weight (Mw) of the second binder in the above [1] or [2] is 100,000 to 1,000,000 g / mol. [4] The present invention provides a binder composition in which, in at least one of the above [1] to [3], the total content of the first binder resin and the second binder resin is 0.2 wt% to 5.0 wt% based on the total content of the binder composition. [5] The present invention provides a binder composition in which, in at least one of the above [1] to [4], the weight ratio of the first binder resin and the second binder resin is 3:7 to 5:5. [6] The present invention provides a binder composition in at least one of the above [1] to [5], wherein the viscosity of the binder composition is 500 cP to 50,000 cP in an aqueous solution state of 2.5 wt% at 25°C. [7] The present invention provides a negative electrode active material slurry comprising a silicon-based negative electrode active material and the binder composition of [1]. [8] The present invention provides a negative electrode active material slurry according to the above [7], wherein the negative electrode active material slurry additionally includes a carbon-based negative electrode active material. [9] The present invention provides a negative electrode active material slurry in which the weight ratio of the carbon-based negative electrode active material and the silicon-based negative electrode active material in the above [7] or [8] is 80:20 to 99:1.

[0010] The present invention provides a negative electrode active material slurry, wherein, in at least one of the above [7] to [9], the binder composition is included in an amount of 0.1 wt% to 5.0 wt% based on the total weight of the negative electrode active material slurry.

[0011] The present invention provides a negative electrode active material slurry, wherein in at least one of the above [7] to

[0010] , the negative electrode active material slurry further includes a third binder resin.

[0012] The present invention provides a negative electrode active material slurry in which, in at least one of the above [7] to

[0011] , the third binder resin is styrene butadiene rubber.

[0013] The present invention provides a negative electrode active material slurry, wherein, in at least one of the above [7] to

[0012] , the third binder resin is included in an amount of 0.1 wt% to 5.0 wt% based on the total weight of the negative electrode active material slurry.

[0014] The present invention provides a negative electrode active material slurry, wherein in at least one of the above [7] to

[0013] , the negative electrode active material slurry further includes a conductive material.

[0015] The present invention provides a slurry of a negative electrode active material, wherein in at least one of the above [7] to

[0014] , the conductive material is at least one of a single-walled carbon nanotube (SWCNT), a thin-walled carbon nanotube (TWCNT), a multi-walled carbon nanotube (MWCNT), carbon fiber, and graphene.

[0016] The present invention provides a negative electrode comprising: a negative electrode current collector; and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector; wherein the negative electrode active material layer is formed by applying the negative electrode active material slurry of [7].

[0017] The present invention provides a cathode having an adhesive strength of 23.2 gf / 20 mm to 25 gf / 20 mm and an energy efficiency of 96% or more in a life evaluation of 100 cycles, in the above

[0016] .

[0018] The present invention provides a lithium secondary battery including the negative electrode of

[0016] . The binder composition of the present invention comprises a lithium-substituted polyacrylic acid having a weight average molecular weight (Mw) of 300,000 to 1,500,000 g / mol and a lithium-substituted carboxymethyl cellulose having a weight average molecular weight (Mw) of 50,000 to 1,000,000 g / mol in a specific composition ratio, thereby effectively suppressing volume expansion of a silicon-based active material, thereby preventing cracks on the surface of an anode, and improving the adhesion between the anode active material layer and a current collector, and enhancing lithium ion mobility, thereby enabling the manufacture of an anode having superior durability and charge / discharge efficiency. Therefore, by applying the anode of the present invention, a lithium secondary battery having improved output characteristics and cycle characteristics can be realized. Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner. Meanwhile, in this specification, "weight average molecular weight" can be measured using a gel permeation chromatography (GPC) device. Specifically, in the present invention, the measurement is performed using the Agilent 1200 series under GPC conditions, and the column used here can be an Agilent PL mixed B column, and the solvent can be THF or DMF. Meanwhile, unless otherwise specifically specified in this specification, molecular weight may mean weight average molecular weight. In addition, in this specification, "viscosity" can be measured using a B-type viscometer (VISCOMETER, TOKIMEC) or a rheometer (Rheometer, TA instruments) for a test body in a 2.5 wt% aqueous solution state. Specifically, in the present invention, "viscosity" can be measured using a B-type viscometer (VISCOMETER, TOKIMEC) (25°C, 12 rpm) for a test body in a 2.5 wt% aqueous solution state. In the past, when manufacturing lithium secondary batteries, a mixture of styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC), or a binder such as polyvinylidene fluoride (PVDF) was mainly used as an anode binder. The above styrene-butadiene rubber has the advantage of not significantly affecting conductivity when used as a binder, but has a relatively weak bonding strength, so an excessive amount of binder must be used to maintain the bonding strength, which has the disadvantage of lowering electrical conductivity and significantly deteriorating cycle characteristics. Carboxymethyl cellulose (CMC), a thickener used in combination with the above styrene-butadiene rubber (SBR), has the advantage of being inexpensive and easy to manufacture, but has the disadvantage of having a weak bonding strength with the surface of the silicon-based negative electrode active material, as well as a weak bonding strength with byproducts decomposed from the electrolyte salt, making it difficult to form a strong SEI film. In addition, the above polyvinylidene fluoride has almost no swelling and can secure excellent bonding strength, but has the disadvantage of swelling upon reacting with most organic electrolytes, such as propylene carbonate, and damaging a portion of the negative electrode. In particular, the above binders do not effectively suppress the volume expansion of the silicon-based active material in the negative electrode containing the silicon-based active material during charge and discharge, thereby causing structural destruction, peeling, or deformation of the negative electrode, which causes a problem of deterioration in the capacity and cycle characteristics of the secondary battery. Accordingly, the inventors of the present invention have conducted repeated studies to develop a binder that can secure excellent adhesiveness between negative electrode active material particles and / or between the negative electrode active material and a current collector, while effectively suppressing volume expansion of the silicon-based negative electrode active material. As a result, they have discovered that when a lithium-substituted polyacrylic acid having a specific weight average molecular weight range and a lithium-substituted carboxymethyl cellulose having a specific weight average molecular weight range are mixed at a specific composition ratio, excellent electrode adhesiveness (bonding force) can be secured, lithium ion aggregation can be improved, and a solid film can be formed on the surface of the silicon-based negative electrode active material to suppress volume expansion, thereby completing the present invention. Hereinafter, the present invention will be described in more detail. The binder composition according to the present invention, the negative electrode active material slurry and negative electrode including the same, and the lithium secondary battery include at least one of the following disclosed configurations, and may include any combination between technically possible configurations among the following configurations. binder composition The binder composition according to the present invention Containing a first binder resin, a second binder resin and water, The first binder resin comprises a lithium-substituted polyacrylic acid having a weight average molecular weight (Mw) of 300,000 g / mol to 1,500,000 g / mol, The second binder resin may include lithium-substituted carboxymethyl cellulose having a weight average molecular weight (Mw) of 50,000 g / mol to 1,000,000 g / mol. (1-1) First binder resin The first binder resin may include lithium-substituted polyacrylic acid. The above lithium-substituted polyacrylic acid may be one type of lithium-substituted polyacrylic acid, or two or more types of lithium-substituted polyacrylic acids having different molecular weights may be used in combination. When lithium-free polyacrylic acid is used as a binder resin for conventional negative electrode active material slurries, the internal pressure increases due to hydrogen gas generated from the polyacrylic acid during charge and discharge, which can cause cell swelling. Furthermore, the side reaction between the generated hydrogen and fluorine element decomposed from the electrolyte salt forms Lewis acid (HF), which reduces the SEI formation effect and can cause side reactions such as electrode collector corrosion and internal cell corrosion. To improve these problems, the present invention uses lithium-substituted polyacrylic acid instead of the lithium-non-substituted polyacrylic acid as the first binder resin, thereby suppressing hydrogen gas generation from the polyacrylic acid and preventing battery expansion. Furthermore, the lithium-substituted polyacrylic acid has a terminal -COO included in its structure. - By forming a film on the surface of the silicon-based active material (SiOx) that can suppress volume expansion by the functional group, crack induction can be suppressed, and by securing the bonding force between the silicon-based active material (SiOx) and the adhesive force between the silicon-based active material and the surface of the current collector, the silicon-based negative electrode active material can be prevented from being detached from the surface of the current collector, thereby reducing the phenomenon of short circuiting and peeling of the negative electrode. In addition, the lithium-substituted polyacrylic acid is substituted -Li + Anionic components decomposed from the electrolyte salt, such as PF6 decomposed from LiPF6 or LiFSI, etc. - or FSI -By reacting with anionic components such as lithium, a strong film containing a fluorine component can be formed on the surface of the negative electrode, so that the volume expansion of the silicon-based negative electrode can be effectively suppressed during repeated charge and discharge. In addition, the lithium-substituted polyacrylic acid has higher electrical conductivity than lithium-unsubstituted polyacrylic acid in the same content range, and thus can exhibit better high-efficiency charge and discharge characteristics. As such, in the present invention, by applying a binder composition including a lithium-substituted polyacrylic acid as the first binder resin, a lithium secondary battery having excellent charge and discharge capacity and cycle life (capacity retention rate) can be implemented. Meanwhile, the lithium-substituted polyacrylic acid of the present invention is a form in which all hydrogens of the carboxyl groups (COOH) included in the structure are replaced with lithium, and can be formed through a neutralization reaction by adding lithium hydroxide (LiOH) to polyacrylic acid. Specifically, the lithium-substituted polyacrylic acid can be formed by adding lithium hydroxide so that the amount of carboxyl groups and lithium of the polyacrylic acid is 1:1 molar ratio, and completely neutralizing the polyacrylic acid while stirring at room temperature (25°C) for 12 hours. At this time, if the amount of lithium hydroxide added is small, the polyacrylic acid is not completely neutralized, and therefore a side reaction may be induced by hydrogen generated from the polyacrylic acid during charge and discharge. In addition, when a relatively large amount of lithium hydroxide is added, the -OH functional group of lithium hydroxide, which does not participate in the neutralization reaction, binds to the surface of the silicon-based negative electrode active material, causing a side reaction that interferes with the binding of the -COO functional group. As a result, a solid SEI film cannot be formed on the negative electrode surface, which may deteriorate the battery life characteristics. The pH of the neutralized lithium-substituted polyacrylic acid may be 6 to 9. In particular, the weight average molecular weight (Mw) of the lithium-substituted polyacrylic acid of the present invention may be 300,000 to 1,500,000 g / mol, specifically 500,000 to 1,500,000 g / mol, and more specifically 500,000 to 1,000,000 g / mol. Preferably, the weight average molecular weight (Mw) of the lithium-substituted polyacrylic acid of the present invention may be 600,000 to 800,000 g / mol. When the weight average molecular weight of the lithium-substituted polyacrylic acid is less than 300,000 g / mol, the adhesive strength with the active material or the current collector may not be sufficient, and thus the improvement effect on the adhesive properties of the electrode and the cycle characteristics of the battery may be minimal. In addition, if the weight average molecular weight of the lithium-substituted polyacrylic acid exceeds 1,500,000 g / mol, the viscosity of the binder composition increases, making it difficult to manufacture an electrode sheet, and the adhesive strength of the electrode may be excessively increased, thereby acting as a resistor within the electrode, thereby reducing the mobility of lithium ions. Furthermore, if the manufacturing cost for improving the processability of the lithium-substituted polyacrylic acid is added, the disadvantage of an increase in the unit price of the entire cell may be caused. Meanwhile, in the present invention, one type of lithium-substituted polyacrylic acid may be used as the first binder resin, or two or more types of lithium-substituted polyacrylic acids having different weight average molecular weights may be appropriately combined and used in order to improve adhesion and processability and to suppress volume expansion of silicon-based materials. A lithium-substituted polyacrylic acid having a relatively high molecular weight can contribute to increasing the adhesion of the binder and improving the lifespan stability of the battery, and a lithium-substituted polyacrylic acid having a relatively low molecular weight can increase the solid content during slurry preparation and increase the flowability of the slurry, thereby contributing to improving the processability of the binder. Specifically, in the present invention, a first lithium-substituted polyacrylic acid having a relatively low molecular weight (weight average molecular weight (Mw): 300,000 g / mol or more and less than 1,000,000 g / mol) and a second lithium-substituted polyacrylic acid having a relatively high molecular weight (weight average molecular weight (Mw): 1,000,000 g / mol or more and less than 1,500,000 g / mol) may be used in combination, if necessary. (1-2) Second binder resin In the present invention, the second binder resin may include lithium-substituted carboxymethyl cellulose. When lithium-free carboxymethyl cellulose (CMC-Na) is applied as a conventional binder resin, sodium (Na) contained in carboxymethyl cellulose + ) ions act as impurities, hindering the movement of lithium ions, increasing the resistance within the electrode, and thus deteriorating the battery life and output characteristics. In order to improve these problems, in the present invention, when the second binder resin includes lithium-substituted carboxymethyl cellulose (CMC-Li) instead of the lithium-unsubstituted carboxymethyl cellulose (CMC-Na), Na + It can prevent the increase in resistance due to ions and facilitate the insertion / de-insertion of lithium from the negative electrode during charging and discharging, thereby improving the lifespan. In particular, the lithium-substituted carboxymethyl cellulose (CMC-Li) contains a number of cellulose functional groups with excellent adhesive strength within its structure. Therefore, when lithium-substituted carboxymethyl cellulose (CMC-Li) is applied as the second binder resin, the bonding strength between silicon-based active materials (SiOx) or the adhesive strength between silicon-based active materials and a current collector, which is reduced due to the influence of the acrylic acid groups contained in the first binder, can be further secured, and the -COO contained within the structure during charge and discharge - Li + It can form a more robust film on the cathode surface by reacting with the anionic components generated by the functional group and electrolyte salt decomposition. Therefore, the expansion of the silicon-based cathode active material caused by charge and discharge can be more effectively suppressed. Meanwhile, the lithium-substituted carboxymethyl cellulose contains sodium (Na) contained within the carboxymethyl cellulose (CMC-Na) structure. + ) is a form in which all elements are substituted with lithium, and can be formed through a neutralization reaction by adding lithium hydroxide to carboxymethyl cellulose. Specifically, the lithium-substituted carboxymethyl cellulose can be formed by adding lithium hydroxide so that the amount of carboxyl group and lithium of carboxymethyl cellulose (CMC-Na) is 1:1 molar ratio, and completely neutralizing carboxymethyl cellulose (CMC-Na) while stirring at room temperature (25°C) for 12 hours. At this time, if the amount of lithium hydroxide added is small, carboxymethyl cellulose is not completely neutralized, so sodium (Na) included in the carboxymethyl cellulose (CMC-Na) structure + ) ions remain without being partially replaced. The remaining sodium (Na) +) ions, as described above, dissociate into the electrolyte during subsequent battery operation and act as impurities, remaining on the negative electrode surface and lithium pathway to impede the movement of lithium ions, which may result in increased resistance within the electrode, decreased conductivity, and deterioration of battery life characteristics. In addition, when performing the neutralization reaction, if the lithium hydroxide is added in a somewhat excessive amount, the negative electrode active material slurry forms a high pH due to the excess lithium hydroxide that has been displaced and remains. As a result, there is a disadvantage in that the aggregation phenomenon increases within the negative electrode active material slurry, aggravating the roughness of the negative electrode surface, and thus deteriorating the battery life characteristics. In particular, the weight average molecular weight (Mw) of the lithium-substituted carboxymethyl cellulose (CMC-Li) of the present invention may be 50,000 to 1,000,000 g / mol, specifically 100,000 to 1,000,000 g / mol, and more specifically 100,000 to 500,000 g / mol. Preferably, the weight average molecular weight (Mw) of the lithium-substituted carboxymethyl cellulose (CMC-Li) of the present invention may be 100,000 to 300,000 g / mol. When the weight average molecular weight of the lithium-substituted carboxymethyl cellulose (CMC-Li) is less than 50,000 g / mol, the viscosity of the binder composition decreases, which increases the drying temperature and drying time, which may cause wrinkles and cracks on the electrode surface, and the adhesive strength between the negative electrode active material and the current collector decreases, which may cause detachment of the negative electrode active material. In addition, when the weight average molecular weight of the lithium-substituted carboxymethyl cellulose (CMC-Li) exceeds 1,000,000 g / mol, the viscosity of the binder composition increases, which not only makes it difficult to manufacture an electrode sheet, but also excessively increases the adhesive strength of the electrode, which may act as a resistor in the electrode, thereby reducing the mobility of lithium ions. (1-3) Solvent Meanwhile, the remainder of the binder composition of the present invention, excluding the first binder resin and the second binder resin, may include a solvent not mentioned separately, and such solvent may include water. Meanwhile, the total content of the first binder resin and the second binder resin in the binder composition of the present invention may be 0.2 to 5.0 wt% based on the total content of the binder composition. When the total content of the first binder resin and the second binder resin satisfies the above range, the formulation stability of the binder composition can be maintained, while the adhesive strength and battery performance improvement effects of the binder can be realized. If the total content of the first binder resin and the second binder resin is 0.2 wt % or more, the adhesive strength (bonding strength) of the binder and the cycle performance of the battery can be improved, and when the total content of the first binder resin and the second binder resin is 5.0 wt % or less, the viscosity of the binder composition can be prevented from increasing, so that the dispersibility can be improved when manufacturing the electrode slurry, thereby preventing the electrode slurry from agglomerating or the activity from being reduced. Specifically, the total content of the first binder resin and the second binder resin may be 0.2 to 3.0 wt%, more specifically 0.2 to 1.0 wt%, based on the total content of the binder composition. Meanwhile, in the binder composition of the present invention, the first binder resin and the second binder resin may be mixed and used in a weight ratio of 3:7 to 5:5, or may be mixed and used in a weight ratio of 4:6 to 5:5. When the weight ratio of the first binder resin and the second binder resin satisfies the above range, Li is improved by improving the bonding strength (adhesion) of the silicon-based negative electrode active material. +By improving ion and electron mobility, conductivity can be improved, cracks caused by volume expansion of silicon-based negative electrode active materials can be suppressed, and at the same time, the silicon-based negative electrode active materials can be prevented from detaching from the surface of the current collector, thereby reducing short-circuiting and peeling of the negative electrode, and a more robust film can be formed on the surface of the negative electrode, thereby securing excellent charge-discharge capacity and cycle life characteristics. At this time, when the ratio of the second binder resin to the first binder resin is less than 5 weight ratio, the adhesive strength is relatively lowered due to the effect of decreasing the cellulose content, so that the silicon-based active material may have relatively minimal effects such as suppressing volume expansion, preventing short-circuiting of the negative electrode, and forming a film. In addition, when the ratio of the second binder resin to the first binder resin exceeds 7 weight ratio, for example, when the content of lithium-substituted carboxymethyl cellulose in the binder composition exceeds the above range, the effect of forming a fluorine-containing film on the surface of the silicon-based negative electrode active material is reduced due to the influence of some hydroxyl groups (-OH) present in the lithium-substituted carboxymethyl cellulose structure, so that particle cracks may occur in the silicon-based active material during charge and discharge, which may cause a decrease in conductivity and volume expansion, thereby somewhat deteriorating the life characteristics of the battery. Meanwhile, the viscosity of the binder composition of the present invention may be 500 to 50,000 cP in a 2.5 wt% aqueous solution state at a temperature of 25°C, specifically 1,000 to 50,000 cP, more specifically 1,000 to 10,000 cP, and preferably 3,000 to 5,000 cP. When the viscosity of the binder composition of the present invention satisfies the above range, the formulation stability of the binder composition can be maintained, while excellent binder adhesiveness can be secured, and the dispersibility can be improved during the preparation of the electrode slurry to prevent agglomeration of the electrode slurry and realize the effect of improving battery performance. Negative active material slurry According to another embodiment, the present invention provides a negative electrode active material slurry comprising a silicon-based negative electrode active material and a binder composition of the present invention. The negative electrode active material slurry of the present invention may additionally include a carbon-based negative electrode active material, if necessary. Furthermore, the negative electrode active material slurry of the present invention may additionally include a third binder resin and / or a conductive agent, if necessary. (2-1) Silicon-based negative electrode active material Since the above silicon-based negative electrode active material exhibits higher capacity characteristics than the carbon-based negative electrode active material, better capacity characteristics can be obtained than the carbon-based negative electrode active material. Representative examples of these silicon-based negative electrode active materials include metallic silicon (Si) and silicon oxide (SiO). x , here 0 <x<2) 실리콘 탄화물(SiC) 및 Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님)로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다. 상기 원소 Y로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db (dubnium), Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합으로 이루어진 군에서 선택될 수 있다. (2-2) Carbon-based negative electrode active material Meanwhile, the negative electrode active material slurry of the present invention may additionally include a carbon-based negative electrode active material, if necessary. Examples of such carbon-based negative electrode active materials include various carbon-based negative electrode active materials used in the art, such as graphite-based materials such as natural graphite, artificial graphite, and Kish graphite; high-temperature calcined carbon such as pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and petroleum or coal tar pitch derived cokes, soft carbon, and hard carbon. The shape of the carbon-based negative electrode active material is not particularly limited, and materials of various shapes such as amorphous, plate-like, flaky, spherical, or fibrous may be used. Meanwhile, when the carbon-based negative electrode active material and the silicon-based negative electrode active material are mixed and used, the weight ratio of the carbon-based negative electrode active material and the silicon-based negative electrode active material may be 80:20 to 99:1, or may be 85:15 to 95:5, and more specifically, may be 97:3 to 99:1. When the mixing ratio of the silicon-based negative electrode active material and the carbon-based negative electrode active material satisfies the above range, the capacity characteristics are improved while the volume expansion of the silicon-based negative electrode active material is suppressed, thereby ensuring excellent cycle performance. Meanwhile, the total content of the negative active material may be comprised between 80 wt% and 99 wt% based on the total weight of the negative active material slurry. When the total content of the negative active material satisfies the above range, excellent capacity characteristics and electrochemical characteristics can be obtained. (2-3) Binder composition The description of the binder composition included in the negative electrode active material slurry of the present invention overlaps with the above-described content, and therefore, its description is omitted. However, with respect to the binder composition content, the binder composition may be included in an amount of 0.1 wt% to 5.0 wt%, or may be included in an amount of 0.1 wt% to 3.0 wt%, based on the total weight of the negative active material slurry of the present invention. When the binder composition is included in the above content range, high-capacity design is possible and an effect of improving life characteristics can be implemented. Specifically, when the binder composition is included in an amount of less than 0.1 wt%, not only is the effect of suppressing volume expansion of the silicon-based negative electrode active material during charge and discharge minimal, but the adhesive strength between the current collector and the active material is not secured, which may cause detachment of the active material. In addition, when the binder composition exceeds 5.0 wt%, the capacity is reduced due to a decrease in the positive electrode active material content due to the binder composition being included in a somewhat large amount, and the life characteristics may deteriorate due to a resistance action within the electrode caused by the binder. (2-4) Third binder resin Meanwhile, the negative electrode active material slurry of the present invention may additionally include a third binder resin to improve the flexibility of the negative electrode. The third binder resin may include styrene-butadiene rubber. The third binder resin may be included in an amount of 0.1 wt% to 5.0 wt% based on the total weight of the negative active material slurry. When the third binder resin is included within the above content range, the flexibility of the negative electrode can be improved, thereby suppressing electrode breakage during electrode assembly or repeated charge / discharge. Specifically, when the third binder resin is included in an amount of less than 0.1 wt%, electrode flexibility is not secured, and thus electrode cracks may be induced due to volume expansion during electrode assembly or charge / discharge. In addition, when the content of the third binder resin exceeds 5.0 wt%, a side reaction may be induced in which the battery capacity decreases due to a decrease in the negative electrode active material content, and the battery life characteristics deteriorate as the resistance within the electrode increases. (2-5) Challenge In addition, the negative electrode active material slurry of the present invention may additionally include a conductive agent to further improve the conductivity of the negative electrode active material. The conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and representative examples thereof may include at least one of a single-walled carbon nanotube (SWCNT), a thin-walled carbon nanotube (TWCNT), a multi-walled carbon nanotube (MWCNT), carbon fiber, and graphene. Such a conductive material may be included in an amount of 1.0 wt% to 30 wt%, preferably 1.0 wt% to 20 wt%, and more preferably 1.0 wt% to 10 wt%, based on the total weight of the negative electrode active material layer. Meanwhile, if the conductive agent is included in an amount less than 1.0 wt%, it may be difficult to expect an improvement in electrical conductivity or the electrochemical characteristics of the battery may deteriorate. Furthermore, if the conductive agent is included in an amount exceeding 20.0 wt%, the ratio of the silicon-based negative electrode active material and the binder may relatively decrease, resulting in a decrease in battery capacity and energy density. (2-6) Solvent Meanwhile, the negative active material slurry of the present invention may include a solvent. Such solvents may include water or organic solvents such as NMP or alcohol, and may be used in an amount that provides a desirable viscosity when including the negative electrode active material, binder composition, and optionally a conductive material. For example, the solvent may be included so that the solid content concentration in the negative electrode active material slurry is 50 wt% to 75 wt%, preferably 40 wt% to 70 wt%. Among the negative electrode active material slurry of the present invention, the remainder, excluding the silicon-based negative electrode active material, binder composition, carbon-based negative electrode active material, third binder resin, and conductive material, may include a solvent unless otherwise specified. Meanwhile, the negative electrode active material slurry of the present invention can be manufactured by dissolving or dispersing the silicon-based negative electrode active material, the binder composition, and optionally at least one of the carbon-based negative electrode active material, the third binder resin, and the conductive material in the solvent. cathode In another embodiment, the present invention provides a negative electrode comprising: a negative electrode current collector; and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector; wherein the negative electrode active material layer is formed by applying a negative electrode active material slurry of the present invention. The above negative electrode current collector generally has a thickness of 3 to 500 μm. The negative electrode current collector is not particularly limited as long as it has high conductivity and does not cause chemical changes in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, like the positive electrode current collector, the bonding strength of the negative electrode active material can be strengthened by forming fine unevenness on the surface, and can be used in various forms such as a film, sheet, foil, net, porous body, foam, non-woven fabric, etc. Meanwhile, the negative electrode of the present invention can be manufactured according to a negative electrode manufacturing method known in the art. For example, it can be manufactured by a method of forming a negative electrode active material layer by applying the negative electrode active material slurry on a negative electrode current collector, rolling, and drying, or by casting a negative electrode active material layer using the negative electrode active material slurry on a separate support, then peeling off the support, and laminating the resulting film on a negative electrode current collector. The cathode of the present invention may have an adhesive strength of 24 gf / 20 mm to 25 gf / 20 mm and an energy efficiency of 96% or more in a life evaluation of 100 cycles. The adhesive strength was calculated by cutting the rolled electrode into a size of 15 cm × 2 cm, adhering the electrode surface to a slide glass with double-sided tape, and manufacturing three samples for a peel test through lamination, loading each sample into a UTM (Universal Testing Machine), and measuring the peel resistance (gf / cm) by performing a 90° peel test. secondary batteries In addition, in another embodiment of the present invention, a lithium secondary battery including the negative electrode of the present invention is provided. Specifically, the lithium secondary battery includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, and the negative electrode may include the negative electrode of the present invention. At this time, since the cathode of the present invention has been described above, its description will be omitted, and other components will be described below. (3-1) Bipolar The positive electrode according to the present invention may include a positive electrode active material layer including a positive electrode active material, and, if necessary, the positive electrode active material layer may further include a conductive material and / or a binder. The above positive electrode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically may include a lithium composite metal oxide containing lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. Specifically, the positive electrode active material is a lithium-cobalt oxide (e.g., LiCoO2, etc.), a lithium-manganese oxide (e.g., LiMnO2, LiMn2O4, etc.), a lithium-nickel oxide (e.g., LiNiO2, etc.), a lithium-nickel-manganese oxide (e.g., LiNi 1-Y Mn Y O2 (here, 0 <Y<1), LiMn 2-z Ni z O4 (where 0<Z<2), etc.), lithium-nickel-cobalt oxides (e.g., LiNi 1-Y1 Co Y1 O2 (here, 0 <Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-Y2 Mn Y2 O2 (here, 0 <Y2<1), LiMn 2-z1 Co z1 O4 (wherein, 0<Z1<2) etc.), lithium-nickel-manganese-cobalt oxides (e.g., Li(Ni p Co q Mn r1 )O2(wherein, 0<p<1, 0<q<1, 0<r1<1, p+q+r1=1) or Li(Ni p1 Co q1 Mn r2 )O4 (wherein, 0<p1<2, 0<q1<2, 0<r2<2, p1+q1+r2=2) etc.), lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r3 M S2)O2 (wherein, M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, Ti, and Mo, and p2, q2, r3, and s2 are atomic fractions of independent elements, respectively, 0<p2<1, 0<q2<1, 0<r3<1, 0<s2<1, p2+q2+r3+s2=1), and the like, and one or more compounds thereof may be included. In order to increase the capacity characteristics and stability of the battery, the positive electrode active material may include at least one selected from the group consisting of lithium-cobalt oxide, lithium-manganese oxide, lithium-nickel-manganese-cobalt oxide, and lithium-nickel-cobalt-transition metal (M) oxide. Specifically, the positive electrode active material may include at least one selected from a lithium-nickel-manganese-cobalt oxide having a nickel content of 55 atm% or more and a lithium-nickel-cobalt-transition metal (M) oxide having a nickel content of 55 atm% or more. Specifically, the positive electrode active material may include a lithium-nickel-manganese-cobalt oxide represented by the following chemical formula 1. [Chemical Formula 1] Li(Ni) a Co b Mn c M d )O2 In the above chemical formula 1, M is W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B or Mo, a, b, c and d are the atomic fractions of independent elements, respectively. 0.55≤a<1, 0 <b≤0.3, 0<c≤0.3, 0≤d≤0.1, a+b+c+d=1이다. Specifically, the above a, b, c and d may be 0.60≤a≤0.95, 0.01≤b≤0.20, 0.01≤c≤0.20, and 0≤d≤0.05, respectively. More specifically, a, b, c, and d may be 0.80≤a≤0.95, 0.02≤b≤0.15, 0.02≤c≤0.15, and 0≤d≤0.03, respectively. Specifically, the above positive electrode active material is a representative example of Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.65 Mn 0.2 Co 0.15 )O2, Li(Ni 0.7 Mn 0.2 Co 0.1 )O2, Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, Li(Ni 0.85 Co 0.05 Mn 0.08 Al 0.02 )O2 and Li(Ni 0.93 Co 0.02 Mn 0.03 Al 0.02 ) At least one species selected from the group consisting of O2 can be mentioned. The above positive electrode active material may be included in an amount of 80 wt% to 99 wt%, specifically 90 wt% to 99 wt%, based on the total weight of the solid content in the positive electrode active material layer. In this case, when the content of the positive electrode active material is 80 wt% or less, the energy density may decrease, resulting in a decrease in capacity. The conductive material is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and examples thereof include carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, or thermal black; graphite powder such as natural graphite, artificial graphite, or graphite with a highly developed crystal structure; conductive fibers such as carbon fibers or metal fibers; conductive powders such as fluorinated carbon powder, aluminum powder, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. The above-mentioned conductive agent is typically added in an amount of 1 to 30 wt% based on the total weight of the solid content in the positive electrode active material layer. The above binder is a component that improves adhesion between positive electrode active material particles and adhesiveness between the positive electrode active material and the current collector, and is typically added in an amount of 1 to 30 wt% based on the total weight of the solid content in the positive electrode active material layer. Examples of such binders include a fluororesin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; Polyester-based binders; and silane-based binders, etc. The positive electrode of the present invention as described above can be manufactured according to a positive electrode manufacturing method known in the art. For example, the positive electrode can be manufactured by a method in which a positive electrode slurry prepared by dissolving or dispersing a positive electrode active material, a binder, and / or a conductive agent in a solvent is applied onto a positive electrode current collector, followed by drying and rolling to form a positive electrode active material layer, or a method in which the positive electrode active material layer is cast onto a separate support, and then the support is peeled off to obtain a film, which is then laminated onto a positive electrode current collector. The above-mentioned positive electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used. The solvent may include an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that provides a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material. For example, the solvent may be included so that the solid concentration in the active material slurry including the positive electrode active material and optionally a binder and a conductive material is 10 wt% to 90 wt%, preferably 30 wt% to 80 wt%. (3-2) Setterator, The separator included in the lithium secondary battery of the present invention may be a generally used conventional porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, which may be used alone or in a laminated manner, or a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc., may be used, but is not limited thereto. (3-3) Electrolyte The electrolyte used in the present invention may include various electrolytes that can be used in lithium secondary batteries, such as organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes, and the type thereof is not particularly limited. Specifically, the electrolyte may include an organic solvent and a lithium salt. The organic solvent may be used without any particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group, and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable. The lithium salt may be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt may include at least one of LiPF6 and LiN(SO2F)2 (lithium bis(fluorosulfonyl)imide, LiFSI). The above lithium salt may further include at least one of LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, and LiB(C2O4)2. It is recommended that the concentration of the lithium salt be within the range of 0.1 to 5.0 M, preferably 0.1 to 3.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively. In addition to the essential components of the electrolyte, the electrolyte may additionally include other additives for the purpose of improving the life characteristics of the battery, suppressing battery capacity reduction, and improving the discharge capacity of the battery. These other additives may include, as representative examples, at least one other additive selected from the group consisting of cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds different from the lithium salt included in the electrolyte. Specifically, the other additives include vinylene carbonate (VC), vinylethylene carbonate, fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,3-propene sultone (PRS), 1,4-butene sultone, 1-methyl-1,3-propene sultone, ethylene sulfate (Esa), trimethylene sulfate (TMS), methyl trimethylene sulfate (MTMS), tetraphenylborate, lithium oxalyldifluoroborate, succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, One or more compounds selected from the group consisting of 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, 4-fluorophenylacetonitrile, fluorobenzene, triethanolamine, ethylenediamine, tetravinylsilane, LiN(SO2F)2 (lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF3)2 (lithium bis(trifluoromethane sulfonyl)imide, LiTFSI), LiPO2F2, LiODFB, LiBOB (lithium bisoxalatoborate (LiB(C2O4)2) and LiBF4) may be mentioned. The above-mentioned other additives may be included in an amount of 0.01 to 20 wt% based on the total weight of the electrolyte, and preferably 0.05 to 5.0 wt%. If the content of the above-mentioned other additives is less than 0.01 wt%, the effects of improving the low-temperature output of the battery and the high-temperature storage characteristics and high-temperature life characteristics are minimal, and if the content of the above-mentioned other additives exceeds 20 wt%, there is a possibility that excessive side reactions occur in the electrolyte during charge and discharge of the battery. In particular, when the above-mentioned SEI film forming additives are added in excessive amounts, they may not be sufficiently decomposed at high temperatures and may remain unreacted or precipitated in the electrolyte at room temperature. Accordingly, side reactions that reduce the life or resistance characteristics of the secondary battery may occur. There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape. Hereinafter, the present invention will be described in detail with examples to specifically illustrate it. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. These examples are provided to more fully explain the present invention to those of average skill in the art. [Example] I. Binder resin manufacturing Manufacturing example 1. Polyacrylic acid (Sigma-Aldrich product, weight average molecular weight: 750,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were placed in a stirrer at a molar ratio of 1:1 and dissolved in water under temperature conditions of 25°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing a lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) binder. Manufacturing example 2. Carboxymethyl cellulose (Sigma-Aldrich product, weight average molecular weight: 250,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were placed in a stirrer at a molar ratio of 1:1 and dissolved in water under temperature conditions of 50°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol). Manufacturing example 3. Polyacrylic acid (Sigma-Aldrich product, weight average molecular weight: 290,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were placed in a stirrer at a molar ratio of 1:1 and dissolved in water under temperature conditions of 25°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing a lithium-substituted polyacrylic acid (weight average molecular weight: 290,000 g / mol) binder. Manufacturing example 4. Polyacrylic acid (Sigma-Aldrich product, weight average molecular weight: 1,600,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were added to a stirrer at a molar ratio of 1:1 and dissolved in water under temperature conditions of 25°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing a lithium-substituted polyacrylic acid (weight average molecular weight: 1,600,000 g / mol) binder. Manufacturing Example 5. Carboxymethyl cellulose (Sigma-Aldrich product, weight average molecular weight: 40,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were placed in a stirrer at a molar ratio of 1:1 and dissolved in water under temperature conditions of 50°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing lithium-substituted carboxymethyl cellulose (weight average molecular weight: 40,000 g / mol). Manufacturing example 6. Carboxymethyl cellulose (Sigma-Aldrich product, weight average molecular weight: 1,100,000 g / mol) and lithium hydroxide (Sigma-Aldrich product, LiOH H2O) were placed in a stirrer at a molar ratio of 1:1 and dissolved in water under a temperature condition of 50°C. Thereafter, the mixture was stirred until the pH reached 7, thereby producing lithium-substituted carboxymethyl cellulose (weight average molecular weight: 1,100,000 g / mol). II. Secondary battery manufacturing Example 1. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in the above Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in the above Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 3:7 to manufacture a 1.0 wt% binder composition (viscosity: 3,000 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Cathode manufacturing) A negative electrode slurry (solid content: 60 wt%) was prepared by adding a negative electrode active material (graphite and SiO = 95:5 weight ratio), the above-mentioned manufactured binder composition, styrene-butadiene rubber as a third binder resin, and a conductive material (carbon black) in a weight ratio of 97:1:1:1 to water as a solvent. The negative electrode slurry was applied to a copper (Cu) thin film as a negative electrode current collector with a thickness of 10 μm (13 mg / cm 2 ) and dried, and then roll pressing was performed to manufacture a cathode. (Polar electrode manufacturing) Positive electrode active material particles (Li(Ni) 0.93 Co 0.02 Mn 0.03 Al 0.02)O2), carbon black as a conductive agent and polyvinylidene fluoride as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent in a weight ratio of 98:0.8:1.2 to prepare a cathode slurry (solid content 75.0 wt%). The cathode slurry was applied to a cathode current collector (Al thin film) having a thickness of 15 μm (25 mg / cm 2 ), drying and roll pressing were performed, and the positive electrode was manufactured. (Secondary battery manufacturing) An electrode assembly was manufactured by interposing a porous separator polypropylene between the positive and negative electrodes manufactured above, and then placed in a battery case, and an electrolyte (EC:EMC:DMC = 20:10:70 volume ratio, 0.6 M LiPF6, 0.6 M LiFSI) was injected to manufacture a lithium secondary battery. Example 2. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in the above Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in the above Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 3,000 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Example 3. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in the above Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in the above Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 2:8 to manufacture a 1.0 wt% binder composition (viscosity: 3,500 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Example 4. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in the above Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in the above Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 6:4 to manufacture a 1.0 wt% binder composition (viscosity: 3,400 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 1. (Manufacture of binder composition) The lithium-substituted polyacrylic acid prepared in Manufacturing Example 1 was dissolved alone in water to prepare a 2.5 wt% binder composition (viscosity: 2,400 cP). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 2. (Manufacture of binder composition) The lithium-substituted carboxymethyl cellulose prepared in Manufacturing Example 2 was dissolved alone in water to prepare a 2.5 wt% binder composition (viscosity: 3,000 cP). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 3. (Manufacture of binder composition) A first binder resin, lithium-free polyacrylic acid (manufactured by Aldrich, weight average molecular weight: 750,000 g / mol) and a second binder resin, lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in Manufacturing Example 2, were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 2,800 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 4. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in the above Manufacturing Example 1 as the first binder resin and the lithium-unsubstituted carboxymethyl cellulose (manufactured by LG ensol. Weight average molecular weight: 250,000 g / mol) as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 3,100 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 5. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 290,000 g / mol) manufactured in Manufacturing Example 3 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 2,100 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 6. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 1,600,000 g / mol) manufactured in Manufacturing Example 4 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 250,000 g / mol) manufactured in Manufacturing Example 2 as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 3,400 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 7. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 40,000 g / mol) manufactured in Manufacturing Example 5 as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 2,200 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. Comparative Example 8. (Manufacture of binder composition) The lithium-substituted polyacrylic acid (weight average molecular weight: 750,000 g / mol) manufactured in Manufacturing Example 1 as the first binder resin and the lithium-substituted carboxymethyl cellulose (weight average molecular weight: 1,100,000 g / mol) manufactured in Manufacturing Example 6 as the second binder resin were dissolved in water at a weight ratio of 5:5 to manufacture a 1.0 wt% binder composition (viscosity: 2,700 cP, B-type viscometer (VISCOMETER, TOKIMEC), 25°C, 2.5 wt% aqueous solution). (Secondary battery manufacturing) A negative electrode and a lithium secondary battery including the same were manufactured in the same manner as in Example 1, except that the binder composition manufactured above was used in manufacturing the negative electrode. [Experimental Example] Experimental Example 1. Evaluation of negative electrode adhesion The cathodes manufactured in Examples 1 and 2 and the cathodes manufactured in Comparative Examples 1, 3 to 5 and Comparative Example 7 were cut into 15 cm × 2 cm sizes, and then attached with the electrode surface to a slide glass with double-sided tape, and three samples for peel test were manufactured through lamination. The above samples were loaded into the UTM at 20 mm intervals, and a 90° peel test (propagation speed: 300 mm / min) was performed to measure the peel resistance (gf / cm), and the adhesiveness of each electrode was calculated from this, and the results are shown in Table 1 below. Mixed specific adhesive strength (gf) of the first binder resin and the second binder resin Example 13: 724.1 Example 25: 523.2 Comparative Example 11: 017.3 Comparative Example 35: 522.9 Comparative Example 45: 523.0 Comparative Example 55: 517.9 Comparative Example 75: 522.4 Looking at Table 1 above, it can be seen that the adhesive strength of the negative electrodes manufactured using the binder compositions of Examples 1 and 2 is 23.2 gf or more, whereas the adhesive strength of the negative electrodes manufactured using the binder compositions of Comparative Examples 1, 3 to 5 and Comparative Example 7 is inferior to that of Examples 1 and 2. Experimental Example 2. Cycle Characteristics Evaluation The lithium secondary batteries manufactured in Examples 1 to 4 and the lithium secondary batteries manufactured in Comparative Examples 2 to 8 were subjected to constant current-constant voltage charging up to 4.2 V at a 0.3 C C-rate, constant voltage charging was performed until a 1 / 20 C current was reached, and then initial charging was performed by discharging up to 2.85 V at a 0.5 C C-rate, and the initial capacity was measured. Next, constant current-constant voltage charging was performed up to 4.2 V at the 0.3 C C-rate, constant voltage charging was performed until 1 / 20 C current was reached, and then discharged to 2.85 V at the 0.5 C C-rate, which was considered one cycle, was performed for 100 cycles, and the capacity after 100 cycles was measured. Then, the capacity retention rate after 100 cycles was calculated, and the results are shown in Table 2 below. Capacity retention rate after 100 cycles (%) Example 196.5 Example 296.6 Example 395.8 Example 496.0 Comparative Example 295.4 Comparative Example 394.3 Comparative Example 494.0 Comparative Example 592.7 Comparative Example 693.0 Comparative Example 793.6 Comparative Example 893.6 Looking at Table 2 above, it can be seen that the cycle characteristics of the lithium secondary batteries of Comparative Examples 2 to 8 are deteriorated compared to Examples 1 to 4.

Claims

1. Including a first binder resin, a second binder resin and water, The first binder resin comprises a lithium-substituted polyacrylic acid having a weight average molecular weight (Mw) of 300,000 g / mol to 1,500,000 g / mol, A binder composition comprising lithium-substituted carboxymethyl cellulose having a weight average molecular weight (Mw) of 50,000 g / mol to 1,000,000 g / mol as the second binder resin.

2. In paragraph 1, A binder composition wherein the weight average molecular weight (Mw) of the first binder resin is 500,000 to 1,500,000 g / mol.

3. In paragraph 1, A binder composition wherein the weight average molecular weight (Mw) of the second binder is 100,000 to 1,000,000 g / mol.

4. In paragraph 1, A binder composition wherein the total content of the first binder resin and the second binder resin is 0.2 wt% to 5.0 wt% based on the total content of the binder composition.

5. In paragraph 1, A binder composition wherein the weight ratio of the first binder resin and the second binder resin is 3:7 to 5:

5.

6. In paragraph 1, A binder composition having a viscosity of 500 cP to 50,000 cP in a 2.5 wt% aqueous solution state at 25°C.

7. A negative electrode active material slurry comprising a silicon-based negative electrode active material and the binder composition of claim 1.

8. In paragraph 7, The above negative active material slurry further comprises a carbon-based negative active material.

9. In paragraph 8, A negative electrode active material slurry wherein the weight ratio of the carbon-based negative electrode active material and the silicon-based negative electrode active material is 80:20 to 99:

1.

10. In paragraph 7, A negative electrode active material slurry, wherein the binder composition is included in an amount of 0.1 wt% to 5.0 wt% based on the total weight of the negative electrode active material slurry.

11. In paragraph 7, A negative electrode active material slurry, wherein the negative electrode active material slurry further comprises a third binder resin.

12. In paragraph 11, A negative electrode active material slurry wherein the third binder resin is styrene butadiene rubber.

13. In paragraph 11, A negative electrode active material slurry, wherein the third binder resin is included in an amount of 0.1 wt% to 5.0 wt% based on the total weight of the negative electrode active material slurry.

14. In paragraph 7, The negative active material slurry above further comprises a conductive material.

15. In paragraph 14, A negative electrode active material slurry wherein the above-mentioned conductive material is at least one of a single-walled carbon nanotube (SWCNT), a thin-walled carbon nanotube (TWCNT), a multi-walled carbon nanotube (MWCNT), carbon fiber, and graphene.

16. Negative current collector; and A negative electrode active material layer disposed on at least one surface of the negative electrode current collector; A negative electrode in which the negative active material layer is formed by applying the negative active material slurry of claim 7.

17. In paragraph 16, The above cathode has an adhesive strength of 23.2 gf / 20 mm to 25 gf / 20 mm and an energy efficiency of 96% or more in a life evaluation of 100 cycles.

18. A lithium secondary battery comprising a negative electrode according to Article 16.