Lithium secondary battery and manufacturing method therefor

Abstract

The present invention relates to a lithium secondary battery comprising a cathode, an anode, a separator interposed between the cathode and the anode, and an electrolyte, wherein: the cathode includes a first cathode active material and a second cathode active material having average particle diameters differing from each other; the average particle diameter (D50) of the first cathode active material is greater than the average particle diameter (D50) of the second cathode active material; the first cathode active material and the second cathode active material include single-particle-form particles; the anode comprises a silicon-based anode active material; and, for the lithium secondary battery, the interfacial resistance factor (IRF) value defined by formula 1 is 1 to 1.4. In formula 1, each variable is the same as that described in the present specification.

Description

Lithium secondary battery and method for manufacturing the same Cross-citation with related applications This application claims the benefit of priority to Korean Patent Application No. 10-2023-0188944, filed December 21, 2023, and Korean Patent Application No. 10-2024-0151590, filed October 30, 2024, the entire contents of which are incorporated herein by reference. Technical field The present invention relates to a lithium secondary battery and a method for manufacturing the same, and more specifically, to a lithium secondary battery having improved capacity, resistance characteristics, and life characteristics, for example, high-temperature life characteristics, and a method for manufacturing the same. Recently, with the rapid spread of electronic devices using batteries such as mobile phones, laptops, computers, and electric vehicles, the demand for small, lightweight, and relatively high-capacity secondary batteries is rapidly increasing. In particular, for example, secondary batteries are attracting attention as a power source for portable devices because they are lightweight and have high energy density. Accordingly, research and development efforts are actively being conducted to improve the performance of lithium secondary batteries. In the present invention, by introducing a low-efficiency cathode material that can complement the problem caused by a silicon-based negative electrode active material having high irreversible capacity loss during initial charge and discharge, it is intended to provide a lithium secondary battery having excellent capacity characteristics and life characteristics, for example, excellent high-temperature life characteristics, and a method for manufacturing the same. [1] The present invention is a lithium secondary battery including a cathode; a cathode; a separator interposed between the cathode and the cathode; and an electrolyte; wherein the cathode includes a first cathode active material and a second cathode active material having different average particle diameters, and the average particle diameter (D) of the first cathode active material is 50 ) is the average particle diameter (D) of the second positive electrode active material. 50) is larger than the first positive electrode active material and the second positive electrode active material, the first positive electrode active material and the second positive electrode active material are single-particle particles, the negative electrode includes a silicon-based negative electrode active material, and the lithium secondary battery has an IRF (Interfacial Resistance Factor) value of 1 to 1.4 defined by the following Equation 1. [Formula 1] In the above formula 1, the R n [Ω] means the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, and the R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode. [2] The present invention provides a lithium secondary battery, wherein, in the above [1], the first positive electrode active material includes a first lithium transition metal oxide represented by the following chemical formula 1. [Chemical Formula 1] Li 1+a1 Ni x1 Co y1 Mn z1 Al w1 M 1 v1 O2 In the above chemical formula 1, 0≤a1≤0.3, 0.82≤x1<1.0, 0 <y1≤0.2, 0<z1≤0.2, 0<w1≤0.2, 0≤v1≤0.1이고, M 1 is a doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. [3] The present invention provides a lithium secondary battery, wherein, in the above [1] or [2], the second positive electrode active material includes a second lithium transition metal oxide represented by the following chemical formula 2. [Chemical formula 2] Li 1+a2 Ni x2 Co y2 Mn z2 Al w2 M 2 v2 O2 In the above chemical formula 2, 0≤a2≤0.3, 0.82≤x2<1.0, 0 <y2≤0.2, 0<z2≤0.2, 0<w2≤0.2, 0≤v2≤0.1이고, M 2 is a doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo. [4] The present invention, in at least one of the above [1] to [3], the R n Provides a lithium secondary battery having a resistance of 0.6Ω or less. [5] The present invention, in at least one of the above [1] to [4], the average particle diameter (D) of the first positive electrode active material 50 ) provides a lithium secondary battery having a thickness of 6 μm to 12 μm. [6] The present invention, in at least one of the above [1] to [5], the average particle diameter (D) of the second positive electrode active material 50 ) provides a lithium secondary battery having a thickness of 1.5 μm to 5 μm. [7] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [6], the first positive electrode active material includes a first lithium transition metal oxide and a first coating layer positioned on the surface of the first lithium transition metal oxide particles and containing cobalt (Co) in an amount of 1.5 mol% to 5 mol%. [8] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [7], the second positive electrode active material includes a second lithium transition metal oxide and a second coating layer positioned on the surface of the second lithium transition metal oxide particles and containing cobalt (Co) in an amount of 0.2 mol% to 2.5 mol%. [9] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to [8], the first positive electrode active material includes a first lithium transition metal oxide and includes a first coating layer including cobalt (Co) on the surface of the first lithium transition metal oxide particle, the second positive electrode active material includes a second lithium transition metal oxide and includes a second coating layer including cobalt (Co) on the surface of the second lithium transition metal oxide particle, and the first coating layer contains cobalt in a larger amount than the second coating layer.

[0010] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to [9], the first positive electrode active material and the second positive electrode active material are included in a weight ratio of 80:20 to 40:60.

[0011] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to

[0010] , the negative electrode includes a carbon-based negative electrode active material, and the silicon-based negative electrode active material and the carbon-based negative electrode active material are included in a weight ratio of 1:99 to 30:70.

[0012] The present invention comprises a step (S1) of mixing a first positive electrode active material in distilled water, performing a first washing, and drying; a step (S2) of mixing a second positive electrode active material in distilled water, performing a second washing, and drying; a step (S3) of applying a positive electrode slurry containing the first positive electrode active material and the second positive electrode active material onto a positive electrode current collector to manufacture a positive electrode; a step (S4) of manufacturing an anode containing a silicon-based negative electrode active material; and a step (S5) of manufacturing a lithium secondary battery containing the positive electrode, the negative electrode, and an electrolyte; wherein the first washing is performed at a higher temperature than the second washing, and the average particle diameter (D) of the first positive electrode active material is 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is larger than the first cathode active material and the second cathode active material, the first cathode active material and the second cathode active material include single-particle particles, and the lithium secondary battery has an IRF (Interfacial Resistance Factor) value of 1 to 1.4 defined by the following Equation 1. [Formula 1] In the above formula 1, the R n [Ω] means the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, and the R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode.

[0013] The present invention provides a method for manufacturing a lithium secondary battery, wherein, in the above

[0012] , the first washing is performed at 20°C to 40°C.

[0014] The present invention provides a method for manufacturing a lithium secondary battery, wherein, in the above

[0012] or

[0013] , the second washing is performed at 3°C ​​to 18°C.

[0015] The present invention provides a method for manufacturing a lithium secondary battery, wherein, in at least one of the above

[0012] to

[0014] , the first washing is performed by mixing the first cathode active material in an amount of 50 wt% to 70 wt% based on the total weight of distilled water.

[0016] The present invention provides a method for manufacturing a lithium secondary battery, wherein, in at least one of the above

[0012] to

[0015] , the second washing is performed by mixing the second positive electrode active material in an amount of 65 wt% to 85 wt% based on the total weight of distilled water. According to the present invention, by using a positive electrode active material having excellent capacity characteristics and being a single-particle type particle, the loss of the reversible capacity of the positive electrode due to the irreversible capacity of the silicon-based negative electrode active material can be prevented or suppressed, and at the same time, by controlling the ratio of the interfacial resistance of the positive electrode to the interfacial resistance of the negative electrode within an appropriate range, the resistance between the positive electrode and the negative electrode can be balanced at the end of discharge, and as a result, the life characteristics of the battery can be improved, and the high-temperature life characteristics can be excellent. In addition, the lithium secondary battery according to the present invention can implement a high energy density and further improve the capacity characteristics by including a positive electrode active material having a bimodal particle size distribution. The following drawings attached to this specification illustrate embodiments of the present invention and, together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention; therefore, the present invention should not be interpreted as being limited to matters described in such drawings. Figure 1 is a flow chart explaining a method for manufacturing a lithium secondary battery according to one embodiment of the present invention. Hereinafter, the present invention will be described in more detail. The 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 having meanings and concepts consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best manner. The terminology used in this specification is for the purpose of describing exemplary embodiments only and is not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms “include,” “comprising,” or “having” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the present invention, the "single-particle type particle" means a particle formed by an aggregation of 30 or fewer sub-particles. The sub-particle unit constituting the single-particle type particle is called a nodule. The single-particle type particle includes a single particle composed of one nodule and a pseudo-single particle which is a composite of 2 to 30 nodules. The above “nodule” is a sub-particle unit that constitutes a single particle and a pseudo-single particle, and may be a single crystal without a crystalline grain boundary, or a polycrystal that has no apparent grain boundary when observed under a field of view of 5,000 to 20,000 times using a scanning electron microscope. In the present invention, a “secondary particle” means a particle formed by an aggregation of more than 30 sub-particles. In order to distinguish it from the sub-particles forming a single particle, the sub-particles forming a secondary particle are called “primary particles.” In the present invention, “particle” is a concept including any one or all of a single particle, a quasi-single particle, a primary particle, a nodule, and a secondary particle. In the present invention, "average particle diameter D 50 "It refers to the particle size at 50% of the volume cumulative particle size distribution of the positive electrode active material powder, and can be measured using the laser diffraction method. For example, after dispersing the positive electrode active material powder in a dispersion medium, it can be measured by introducing it into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiating it with ultrasonic waves of about 28 kHz with an output of 60 W, obtaining a volume cumulative particle size distribution graph, and then finding the particle size corresponding to 50% of the volume cumulative amount. In the present invention, the “interfacial resistance (R) of the anode p )" is, after manufacturing a lithium secondary battery including a positive electrode, a negative electrode, and an electrolyte according to the present invention, the lithium secondary battery is charged at 25°C under CC (constant current) / CV (constant voltage), 0.1C, 4.2V, 0.05C cut conditions, and discharged under CC, 0.1C, 3.0V conditions, which is considered as one cycle, and then 100 cycles are performed, and then each lithium secondary battery is charged to SOC (State of Charge) 50% or SOC 10%, and each lithium secondary battery charged to SOC 50% or SOC 10% can be measured using a Biologic VMP3 device (100kHz~10mHz, 25°C). At this time, the electrolyte is manufactured by dissolving 1.0M LiPF6 in an organic solvent mixed with ethylene carbonate (EC): ethyl methyl carbonate (EMC) in a volume ratio of 3:7. You can use it. In the present invention, the “interfacial resistance (R) of the cathode n)" is, after manufacturing a lithium secondary battery including a negative electrode, a positive electrode, and an electrolyte according to the present invention, charging the lithium secondary battery under CC / CV, 0.1C, 0.05V, 0.05C cut conditions at 25°C, and performing 100 cycles of discharging under CC, 0.1C, 1.5V conditions as 1 cycle, then charging each lithium secondary battery to SOC 50% or SOC 10%, and measuring each lithium secondary battery charged to SOC 50% or SOC 10% using a Biologic VMP3 device (100kHz~10mHz, 25°C). At this time, the electrolyte can be used that is manufactured by dissolving 1.0M LiPF6 in an organic solvent mixed with ethylene carbonate (EC): ethyl methyl carbonate (EMC) in a volume ratio of 3:7. Carbonaceous materials such as graphite are mainly used as anode materials for lithium secondary batteries, but carbonaceous materials have a low capacity per unit mass, making it difficult to increase the capacity of lithium secondary batteries. Accordingly, non-carbonaceous anode materials that exhibit higher capacity than carbonaceous materials, such as silicon, tin, and oxides thereof, which form intermetallic compounds with lithium, are being developed and used. However, these anode materials have the problem of a large irreversible capacity loss during initial charge and discharge. In view of this, methods have been studied and proposed to overcome the irreversible capacity loss of the negative electrode by using a material that can provide a lithium ion source or storage as a positive electrode material and is electrochemically active after the first cycle so as not to deteriorate the performance of the battery itself. For example, there is a method of using a lithium nickel-based oxide such as Li2NiO2 as a sacrificial positive electrode material or an overdischarge prevention agent in the positive electrode. However, considering that most of the lithium nickel-based oxides are expensive and generate a lot of lithium byproducts, which increases the amount of gas generated, the present invention provides a lithium secondary battery and a method for manufacturing the same, which have excellent capacity characteristics and life characteristics, such as high-temperature life characteristics, by using a cathode active material that is a single particle. Hereinafter, the present invention will be described in detail. The lithium secondary battery and the method for manufacturing the lithium secondary battery according to the present invention include at least one of the following disclosed configurations, and may include any combination between technically possible configurations among the following configurations. In order to develop a high-capacity cell, a silicon-based negative electrode active material with high capacity can be used, but the silicon-based negative electrode active material has a disadvantage in that it has low charge / discharge efficiency and a high lithium ion loss rate due to irreversible reactions. Therefore, as charge / discharge is repeated, the loss of lithium in the positive electrode active material increases, which rapidly reduces the capacity of the battery during charge / discharge and may cause the collapse of the positive electrode active material structure. At this time, when using a positive electrode active material that is a single particle type, the efficiency of the positive electrode can be lowered during the initial charge / discharge, and accordingly, the loss of the reversible capacity of the positive electrode due to the irreversible capacity of the silicon-based negative electrode active material can be suppressed. However, when using secondary particle-type lithium nickel-based oxides that use single-particle type cathode active materials, the lithium diffusion path becomes longer than when using lithium nickel-based oxides, which reduces the mobility of lithium ions and increases the initial resistance, thereby reducing the cathode resistance. However, in this case, the resistance of the cathode and anode becomes unbalanced, which may deteriorate the cycle characteristics of the battery. Therefore, the present invention provides a lithium secondary battery having excellent capacity characteristics and life characteristics by preventing or suppressing lithium ion loss of a positive electrode active material due to an irreversible reaction of a silicon-based negative electrode active material. Specifically, the present invention uses a positive electrode active material which is a single-particle particle having a bimodal particle size distribution together with a silicon-based negative electrode active material, while appropriately controlling the ratio of the interfacial resistance of the positive electrode to the interfacial resistance of the negative electrode, and controlling the interfacial resistance of the positive electrode within a specific range, thereby implementing high energy density and providing a lithium secondary battery having excellent capacity characteristics and life characteristics, for example, excellent high-temperature life characteristics. Hereinafter, the present invention will be described in more detail. Lithium secondary battery A lithium secondary battery comprising a lithium secondary cathode according to the present invention; an anode; a separator interposed between the cathode and the anode; and an electrolyte; wherein the cathode comprises a first cathode active material and a second cathode active material having different average particle diameters, and the average particle diameter (D) of the first cathode active material is 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is larger than the first positive electrode active material and the second positive electrode active material, the first positive electrode active material comprises single particle-type particles, the negative electrode comprises a silicon-based negative electrode active material, and the lithium secondary battery has an IRF (Interfacial Resistance Factor) value of 1 to 1.4 defined by the following Equation 1. [Formula 1] In the above formula 1, the R n [Ω] means the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, and the R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode. The IRF value is from 1 to 1.4. Specifically, the IRF value may be 1 or more, 1.02 or more, 1.04 or more, 1.06 or more, 1.08 or more, 1.1 or more, 1.12 or more, 1.14 or more, 1.16 or more, 1.18 or more, and may be 1.4 or less, 1.38 or less, 1.36 or less, 1.34 or less, 1.3 or less, 1.28 or less, 1.26 or less, 1.24 or less, 1.22 or less. 1.2 or less. For example, the IRF value may be 1 to 1.4, 1.08 to 1.3, or 1.12 to 1.24. When using a cathode active material that is a single particle type particle, the efficiency of the cathode can be lowered during the initial charge / discharge, but when using a cathode active material that is a single particle type particle, lithium mobility can be reduced. Accordingly, if the interfacial resistance of the cathode is formed low, the reduction in lithium mobility can be suppressed, but this causes a difference in resistance between the cathode and the anode, and degradation is concentrated on the anode with relatively high resistance. Therefore, the lithium secondary battery according to the present invention can reduce the difference in resistance between the positive electrode and the negative electrode by controlling the ratio of the interfacial resistance of the positive electrode and the interfacial resistance of the negative electrode to an appropriate range according to the above formula 1, thereby suppressing degradation of the negative electrode during charge and discharge cycles, thereby improving the life characteristics of the battery. The above 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 more specifically, it may include an electrode assembly including the positive electrode, the negative electrode, and the separator; an electrolyte; and a battery case. Hereinafter, each component of the lithium secondary battery according to the present invention will be described in detail. (1) Electrode assembly An electrode assembly according to the present invention includes an anode and a cathode, and specifically, may further include a separator interposed between the anode and the cathode. Specifically, the electrode assembly can be formed by sequentially stacking an anode, a separator, and a cathode, and the anode and cathode can be mutually insulated by the separator. Meanwhile, the electrode assembly may be of various forms of electrode assemblies well known in the art, for example, a jelly-roll type, a stack type, a stack and lamination type, or a stack and folding type electrode assembly, and its form is not particularly limited. A jelly-roll type electrode assembly can be manufactured by a method of interposing a sheet-shaped separator between a sheet-shaped positive electrode and a sheet-shaped negative electrode and then winding the same in one direction. The stacked electrode assembly can be manufactured by a method of sequentially stacking the cut anode, separator, and cathode after cutting them into a desired shape. A stack-and-lamination type electrode assembly can be manufactured by a method of manufacturing a plurality of unit cells by stacking an anode, a separator, and a cathode, stacking the plurality of unit cells with a separator interposed between them, and then laminating them through a method such as heating. A stack-and-fold type electrode assembly can be manufactured by a method of manufacturing a plurality of unit cells by stacking an anode, a separator, and a cathode, arranging the plurality of unit cells on one side or both sides of a long folding separator, and then winding the folding separator. Hereinafter, each component of the electrode assembly according to the present invention will be described in detail. 1) Bipolar The positive electrode may include a positive electrode active material layer, and according to one embodiment, the positive electrode may include a positive electrode current collector; and a positive electrode active material layer positioned on the positive electrode current collector. As the positive electrode collector, various positive electrode collectors used in the relevant technical field can be used. For example, as the positive electrode collector, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used. The positive electrode collector can typically have a thickness of 3 to 500 ㎛, and fine unevenness can be formed on the surface of the positive electrode collector to increase the adhesion of the positive electrode active material. The positive electrode collector can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc. The above-mentioned positive electrode active material layer may be positioned on the positive electrode current collector, and specifically, may be positioned on one side or both sides of the positive electrode current collector. The above-mentioned positive electrode active material layer may have a single layer or a multilayer structure of two or more layers. The above positive electrode active material layer includes a first positive electrode active material and a second positive electrode active material. The above first cathode active material and the second cathode active material have an average particle diameter (D 50 ) are different, and specifically, the average particle diameter (D) of the first positive electrode active material 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is larger than that of the first cathode active material. Accordingly, when the electrode is rolled, the second cathode active material having a small particle size is filled into the pores of the first cathode active material having a large particle size, thereby increasing the electrode density and realizing a high energy density, thereby achieving high-capacity characteristics. The above first positive electrode active material includes single-particle particles. When the first positive electrode active material includes single-particle particles, since the single-particle particle size is large, the diffusion distance of lithium is long, so that the diffusion resistance increases, so that the positive electrode may have low efficiency, and thus, when applying a silicon-based negative electrode active material, the efficiency can be balanced with the negative electrode. Accordingly, when applying a silicon-based negative electrode active material, the loss of lithium ions due to irreversible capacity can be suppressed, and the occurrence of lithium precipitation on the surface of the negative electrode can be prevented or suppressed, so that the life characteristics of a lithium secondary battery applying the positive electrode according to the present invention can be improved. In addition, when applying the first positive electrode active material which is a single-particle particle, unlike when using a conventional sacrificial positive electrode material, the generation of lithium byproducts due to the sacrificial positive electrode material during charge and discharge can be prevented or suppressed, so that high-temperature storage characteristics and high-temperature life characteristics can be excellent. The above first cathode active material may include a first lithium transition metal oxide containing nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). Unlike ternary lithium transition metal oxides containing nickel, cobalt, and manganese, the first cathode active material according to the present invention further contains aluminum having a strong bonding force with oxygen atoms, thereby being structurally stable, and thereby suppressing cation mixing during charge and discharge, thereby being electrochemically stable at high potentials, so that thermal stability and capacity characteristics can be further improved. In addition, the first cathode active material may include a first lithium transition metal oxide containing nickel at 82 mol% or more among all metals excluding lithium. In this case, high-capacity characteristics of a lithium secondary battery can be implemented. Specifically, the first positive electrode active material may include a first lithium transition metal oxide represented by the following chemical formula 1. [Chemical Formula 1] Li 1+a1 Ni x1 Coy1 Mn z1 Al w1 M 1 v1 O2 In the above chemical formula 1, the M 1 may be at least one doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, or may be at least one doping element selected from the group consisting of W, Y, Ba, Ca, Ti, Mg, Ta and Nb. The above 1+a1 may mean a molar ratio of lithium (Li) in the first lithium transition metal oxide, and may be 0≤a1≤0.3, 0≤a1≤0.2, 0≤a1≤0.15, or 0≤a1≤0.1. When the above range is satisfied, a balance between the remarkable effect of improving the capacity characteristics of the first positive electrode active material according to the Li content control and the sinterability during the manufacture of the first positive electrode active material can be achieved. The above x1 may mean the molar ratio of nickel among the total metals excluding lithium in the first lithium transition metal oxide, and may be 0.82≤x1<1, 0.85≤x1<1, 0.90≤x1<1, or 0.92≤x1<1. When the above range is satisfied, a nickel content sufficient to contribute to charge and discharge in the lithium transition metal oxide is secured, thereby promoting high capacity. The above y1 may mean the molar ratio of cobalt among the total metals excluding lithium in the first lithium transition metal oxide, and 0 <y1≤0.2, 0<y1≤0.18, 0.01≤y1≤0.15, 0.03≤y1≤0.12, 또는 0.05≤y1≤0.10일 수 있다. 상기 범위를 만족할 경우, 코발트를 적은 함량으로 포함하여 비용적인 이점을 가지면서도 양호한 저항 특성 및 출력 특성을 구현할 수 있다. The above z1 may mean the molar ratio of Mn among the total metals excluding lithium in the first lithium transition metal oxide, and 0 <z1≤0.2, 0<z1≤0.18, 0.01≤z1≤0.15, 또는 0.03≤z1≤0.10일 수 있다. 상기 범위를 만족할 경우, 제1 리튬 전이금속 산화물의 구조적 안정성을 향상시킬 수 있다. The above w1 may mean the molar ratio of Al among the total metals excluding lithium in the first lithium transition metal oxide, and 0 <w1≤0.2, 0<w1≤0.18, 0.01≤w1≤0.15, 또는 0.03≤w1≤0.10일 수 있다. 상기 범위를 만족할 경우, 산소와의 높은 결합력으로 인하여 리튬 전이금속 산화물의 열적 안정성을 향상시킬 수 있다. The above v1 is M among all metals except lithium in the first lithium transition metal oxide. 1 It can mean the molar ratio of v1 and can be 0≤v1≤0.1, 0≤v1≤0.08, or 0≤v1≤0.05. The first positive electrode active material may include a first lithium transition metal oxide and a first coating layer positioned on the surface of the first lithium transition metal oxide particles, and the first coating layer may include cobalt (Co). By means of the first coating layer, contact between the lithium transition metal oxide and the electrolyte is blocked, thereby suppressing occurrence of an electrolyte side reaction, thereby suppressing surface structure degradation of the lithium transition metal oxide that may occur during a charge and discharge process, and thereby suppressing an increase in resistance and improving high-temperature life characteristics. The first coating layer may contain cobalt (Co) in an amount of 1.5 mol% to 5 mol%, 2 mol% to 4.5 mol%, 2.3 mol% to 4 mol%, 2.5 mol% to 3.5 mol%, or 2.7 mol% to 3.3 mol%. When the first coating layer contains cobalt in the above range, it contains a larger amount of cobalt than the second coating layer included in the second positive electrode active material described below, thereby lowering the positive electrode interfacial resistance when the SOC of the lithium secondary battery including the positive electrode according to the present invention is 50%, thereby suppressing an increase in initial resistance during charge and discharge due to a decrease in ion mobility when a positive electrode active material that is a single particle is used, thereby improving the life characteristics and high-temperature life characteristics of the battery. The first coating layer may be formed on the entire surface of the first lithium transition metal oxide particle, or may be formed partially. Specifically, when the first coating layer is formed partially on the surface of the first lithium transition metal oxide particle, it may be formed in an area of ​​5% or more and less than 100%, or 20% or more and less than 100% of the entire surface area of ​​the surface of the first lithium transition metal oxide. The average particle diameter (D) of the first positive electrode active material 50) can be 6㎛ to 12㎛. Specifically, the average particle size of the first positive electrode active material may be 6 ㎛ or more, 6.2 ㎛ or more, 6.4 ㎛ or more, 6.6 ㎛ or more, 6.8 ㎛ or more, 7 ㎛ or more, 7.2 ㎛ or more, 7.4 ㎛ or more, 7.6 ㎛ or more, 7.8 ㎛ or more, 8 ㎛ or more, 8.2 ㎛ or more, 8.4 ㎛ or more, and may be 12 ㎛ or less, 11.8 ㎛ or less, 11.6 ㎛ or less, 11.4 ㎛ or less, 11.2 ㎛ or less, 11 ㎛ or less, 10.8 ㎛ or less, 10.6 ㎛ or less, 10.4 ㎛ or less, 10.2 ㎛ or less, 10 ㎛ or less, 9.8 ㎛ or less, 9.6 ㎛ or less, 9.4 ㎛ or less, 9.2 ㎛ or less, 9 ㎛ or less, 8.8 ㎛ or less, 8.6 ㎛ or less. For example, the average particle size of the first positive electrode active material may be 6 ㎛ to 12 ㎛, 7.4 ㎛ to 11 ㎛, 8 ㎛ to 9.6 ㎛, or 8.2 ㎛ to 9 ㎛. When the above range is satisfied, the rolling density of the positive electrode material can be increased, and thus the electrode density is improved during electrode manufacturing, thereby realizing excellent energy density. The above first positive electrode active material may be included in an amount of 20 wt% to 80 wt%, 30 wt% to 70 wt%, or 40 wt% to 60 wt% based on the total weight of the positive electrode active material layer. When the above range is satisfied, the rolling density can be improved to realize high energy density. Meanwhile, the second positive electrode active material includes single-particle particles. When the second positive electrode active material includes single-particle particles, since the single-particle particle size is large, the diffusion distance of lithium is long, so that the diffusion resistance increases, so that the positive electrode may have low efficiency, and thus, when applying a silicon-based negative electrode active material, the efficiency can be balanced with the negative electrode. Accordingly, when applying a silicon-based negative electrode active material, the loss of lithium ions due to irreversible capacity can be suppressed, and the occurrence of lithium precipitation on the surface of the negative electrode can be prevented or suppressed, so that the life characteristics of a lithium secondary battery applying the positive electrode according to the present invention can be improved. In addition, when applying a second positive electrode active material which is a single-particle particle, unlike when using a conventional sacrificial positive electrode material, the generation of lithium byproducts due to the sacrificial positive electrode material during charge and discharge can be prevented or suppressed, so that high-temperature storage characteristics and high-temperature life characteristics can be excellent. The second cathode active material may include a second lithium transition metal oxide containing nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). Unlike ternary lithium transition metal oxides containing nickel, cobalt, and manganese, the second lithium transition metal oxide according to the present invention further contains aluminum having a strong bonding force with oxygen atoms, thereby being structurally stable, and thereby suppressing cation mixing during charge and discharge, thereby being electrochemically stable at high potentials, so that thermal stability and capacity characteristics can be further improved. In addition, the second cathode active material may include a second lithium transition metal oxide containing nickel at about 82 mol% or more among all metals excluding lithium. In this case, high-capacity characteristics of a lithium secondary battery can be implemented. The second positive electrode active material may include a second lithium transition metal oxide represented by the following chemical formula 2. [Chemical formula 2] Li 1+a2 Ni x2 Coy2 Mn z2 Al w2 M 2 v2 O2 In the above chemical formula 2, the M 2 may be at least one doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, or may be at least one doping element selected from the group consisting of W, Y, Ba, Ca, Ti, Mg, Ta and Nb. The above 1+a2 may mean a molar ratio of lithium (Li) in the second lithium transition metal oxide, and may be 0≤a2≤0.3, 0≤a2≤0.2, 0≤a2≤0.15, or 0≤a2≤0.1. When the above range is satisfied, a balance between the remarkable effect of improving the capacity characteristics of the second positive electrode active material according to the Li content control and the sinterability during the manufacture of the second positive electrode active material can be achieved. The above x2 may mean the molar ratio of nickel among the total metal excluding lithium in the second lithium transition metal oxide, and may be 0.82≤x2<1, 0.85≤x2<1, 0.90≤x2<1, or 0.92≤x2<1. When the above range is satisfied, a nickel content sufficient to contribute to charge and discharge in the lithium transition metal oxide is secured, thereby promoting high capacity. The above y2 may mean the molar ratio of cobalt among the total metals excluding lithium in the second lithium transition metal oxide, and 0 <y2≤0.2, 0<y2≤0.18, 0.01≤y2≤0.15, 0.03≤y2≤0.12, 또는 0.05≤y2≤0.10일 수 있다. 상기 범위를 만족할 경우, 코발트를 적은 함량으로 포함하여 비용적인 이점을 가지면서도 양호한 저항 특성 및 출력 특성을 구현할 수 있다. The above z2 may mean the molar ratio of Mn among the total metals excluding lithium in the second lithium transition metal oxide, and 0 <z2≤0.2, 0<z2≤0.18, 0.01≤z2≤0.15, 또는 0.03≤z2≤0.10일 수 있다. 상기 범위를 만족할 경우, 리튬 전이금속 산화물의 구조적 안정성을 향상시킬 수 있다. The above w2 may mean the molar ratio of Al among the total metals excluding lithium in the second lithium transition metal oxide, and 0 <w2≤0.2, 0<w2≤0.18, 0.01≤w2≤0.15, 또는 0.03≤w2≤0.10일 수 있다. 상기 범위를 만족할 경우, 산소와의 높은 결합력으로 리튬 전이금속 산화물의 열적 안정성을 확보할 수 있다. The above v2 is M among all metals except lithium in the second lithium transition metal oxide. 2 It can mean the molar ratio of v2 and can be 0≤v2≤0.1, 0≤v2≤0.08, or 0≤v2≤0.05. The second positive electrode active material may include a second lithium transition metal oxide and a second coating layer positioned on the surface of the second lithium transition metal oxide particles, and the second coating layer may include cobalt (Co). By means of the second coating layer, contact between the lithium transition metal oxide and the electrolyte is blocked, thereby suppressing occurrence of electrolyte side reactions, thereby suppressing surface structure degradation of the lithium transition metal oxide that may occur during a charge and discharge process, and thereby suppressing an increase in resistance and improving high-temperature life characteristics. The first coating layer may contain a larger amount of cobalt than the second coating layer. In this case, the positive electrode interfacial resistance at the SOC of the lithium secondary battery including the positive electrode according to the present invention can be lowered, so that the initial resistance during charge and discharge can be suppressed from increasing due to the decrease in ion mobility when using a positive electrode active material that is a single particle, thereby improving the life characteristics and high-temperature life characteristics of the battery. The second coating layer may contain cobalt (Co) in an amount of 0.2 mol% to 2.5 mol%, 0.3 mol% to 2 mol%, 0.5 mol% to 1.5 mol%, or 0.7 mol% to 1.3 mol%. When the second coating layer contains cobalt in the above range, the second coating layer contains a smaller amount of cobalt than the first coating layer included in the first positive electrode active material described above, thereby lowering the positive electrode interfacial resistance when the SOC of the lithium secondary battery including the positive electrode according to the present invention is 50%, thereby suppressing an increase in initial resistance during charge and discharge due to a decrease in ion mobility when a positive electrode active material that is a single particle is used, thereby improving the life characteristics and high-temperature life characteristics of the battery and improving the energy density. The second coating layer may be formed on the entire surface of the second lithium transition metal oxide particle, or may be formed partially. Specifically, when the second coating layer is formed partially on the surface of the second lithium transition metal oxide particle, it may be formed in an area of ​​5% or more and less than 100%, preferably 20% or more and less than 100% of the entire surface area of ​​the surface of the second lithium transition metal oxide. The average particle diameter (D) of the second positive electrode active material 50) may be 1.5 ㎛ to 5 ㎛. Specifically, the average particle diameter of the second positive electrode active material may be 1.5 ㎛ or more, 1.7 ㎛ or more, 1.9 ㎛ or more, 2 ㎛ or more, 2.2 ㎛ or more, 2.4 ㎛ or more, 2.6 ㎛ or more, 2.8 ㎛ or more, 3 ㎛ or more, and may be 5 ㎛ or less, 4.8 ㎛ or less, 4.6 ㎛ or less, 4.4 ㎛ or less, 4.2 ㎛ or less, 4 ㎛ or less, 3.8 ㎛ or less, 3.6 ㎛ or less, 3.4 ㎛ or less, 3.2 ㎛ or less. For example, the average particle diameter of the second positive electrode active material may be 1.5 ㎛ to 5 ㎛, 2 ㎛ to 4.5 ㎛, 2.6 ㎛ to 4.2 ㎛, 3 ㎛ to 4 ㎛, or 3 ㎛ to 3.4 ㎛. When the above range is satisfied, the rolling density of the cathode material can be increased, and thus the electrode density can be improved during electrode manufacturing, thereby realizing excellent energy density. The above second positive electrode active material may be included in an amount of 20 wt% to 80 wt%, 30 wt% to 70 wt%, or 40 wt% to 60 wt% based on the total weight of the positive electrode active material layer. When the above range is satisfied, the rolling density can be improved to realize high energy density. The above first positive electrode active material and the above second positive electrode active material may be included in a weight ratio of 80:20 to 40:60, 75:25 to 45:55, 70:30 to 50:50, or 65:45 to 55:45. When the above weight ratio is satisfied, the effect of improving the high temperature life characteristics and resistance characteristics while improving the energy density can be maximized. Meanwhile, the positive electrode active material layer may optionally further include at least one of a positive electrode conductive material and a positive electrode binder. The above-described positive electrode conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without special restrictions. According to one embodiment, the positive electrode conductive material may include graphite such as natural graphite or artificial graphite; carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, carbon nanotube, etc.; metal powder or metal fiber such as copper, nickel, aluminum, silver, etc.; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, etc., and one of these may be used alone or a mixture of two or more may be used. The positive electrode conductive material may be typically included in an amount of 1 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1 wt% to 10 wt%, based on the total weight of the positive electrode active material layer. The above positive electrode binder serves to improve adhesion between positive electrode particles and adhesion between the positive electrode and the positive electrode current collector, and the positive electrode binder is selected from the group consisting of a fluorine resin 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 carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; and a polyester binder. And silane binders, etc. can be mentioned, and one of these can be used alone or a mixture of two or more can be used. The positive electrode binder can be included in an amount of 1 wt% to 30 wt%, 1 wt% to 20 wt%, or 1 wt% to 10 wt% with respect to the total weight of the positive electrode active material layer. The above positive electrode can be manufactured by a method of applying positive electrode slurry to one side or both sides of a long sheet-shaped positive electrode collector, removing the solvent of the positive electrode slurry through a drying process, and then rolling. Meanwhile, a positive electrode including a non-coated portion can be manufactured by a method of not applying the positive electrode slurry to some area of ​​the positive electrode collector, for example, one end of the positive electrode collector, during the application of the positive electrode slurry. In addition, the positive electrode slurry can be prepared by dispersing the first positive electrode active material and the second positive electrode active material according to the present invention in a solvent such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water. Meanwhile, at the above anode, the R p is less than 0.85Ω. Specifically, the R p may be 0.85Ω or less, 0.82Ω or less, 0.8Ω or less, 0.78Ω or less, 0.76Ω or less, 0.74Ω or less, 0.72Ω or less, 0.7Ω or less, 0.68Ω or less, 0.66Ω or less, 0.64Ω or less, 0.62Ω or less, 0.6Ω or less, and may be 0.3Ω or more, 0.32Ω or more, 0.34Ω or more, 0.36Ω or more, 0.38Ω or more, 0.4Ω or more, 0.42Ω or more, 0.44Ω or more, 0.46Ω or more, 0.48Ω or more, 0.5Ω or more, 0.52Ω or more, 0.54Ω or more, 0.56Ω or more, or 0.58Ω or more. For example, the Rp may be 0.85Ω or less, 0.3Ω to 0.8Ω, 0.4Ω to 0.7Ω, 0.5Ω to 0.64Ω, or 0.54Ω to 0.6Ω. When the above range is satisfied, the difference between the interface resistance of the positive electrode and the interface resistance of the negative electrode can be adjusted to an appropriate level, thereby simultaneously preventing degradation of the positive electrode and the negative electrode. At this time, the above R p The composition of the first positive electrode active material and the second positive electrode active material, the cobalt content of the first coating layer included in the first positive electrode active material and the second coating layer included in the second positive electrode active material, and the washing conditions during the production of the first positive electrode active material and the second positive electrode active material can be controlled. 2) Cathode The above negative electrode includes a silicon-based negative electrode active material. Specifically, the negative electrode may include a negative electrode current collector; and a negative electrode active material layer; and the negative electrode active material layer may include a silicon-based negative electrode active material. The above negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and 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. The above negative electrode current collector can typically have a thickness of 3 to 500 ㎛. In addition, the negative current collector, like the positive current collector, can form fine irregularities on the surface of the negative current collector to strengthen the bonding strength of the negative active material. For example, it can be used in various forms such as a film, sheet, foil, net, porous body, foam, and non-woven fabric. The negative electrode active material layer may be positioned on the negative electrode current collector, and specifically, may be positioned on one side or both sides of the negative electrode current collector. The negative electrode active material layer may have a single layer or a multilayer structure of two or more layers. The above silicon-based negative electrode active material may be a particle containing silicon (Si). The above silicon-based negative electrode active material is SiO x (0≤x≤2), Si / C composite or a combination thereof. The SiO x (0≤x≤2) may be a form containing Si and SiO2. That is, the x is the SiO x (0≤x≤2) corresponds to the number ratio of O to Si included in the silicon-based negative electrode active material. Or, the silicon-based negative electrode active material is SiO x (0≤x≤2), or can be SiO. When a silicon-based negative electrode active material is included in the negative electrode, it has the advantage of having a very high charge / discharge capacity compared to a conventional carbon-based negative electrode active material. However, since the silicon-based negative electrode active material has a large irreversible capacity, the life characteristics of the battery may be reduced, but the lithium secondary battery according to the present invention includes a positive electrode active material in the form of single particles in the positive electrode, and by controlling the interfacial resistance of the positive electrode to a specific range, it is possible to suppress the reduction in the life characteristics of the battery. The above silicon-based negative electrode active material may be included in the negative electrode active material layer at 1 wt% to 30 wt%, 1 wt% to 25 wt%, or 2 wt% to 20 wt%. When the above range is satisfied, sufficient capacity characteristics can be implemented. Meanwhile, the negative electrode active material layer may further include a carbon-based negative electrode active material as the negative electrode active material. The above carbon-based negative electrode active material may be at least one selected from the group consisting of graphite such as natural graphite or artificial graphite; and carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, and carbon nanotube. When the carbon-based negative electrode active material is included, the deterioration of the life characteristics due to the volume change of the silicon-based negative electrode active material during charge and discharge can be suppressed. When a carbon-based negative electrode active material is further included, the silicon-based negative electrode active material and the carbon-based negative electrode active material may be included in a weight ratio of 1:99 to 30:70, 1.5:98.5 to 20:80, 2:98 to 15:85, or 2.5:97.5 to 10:90. When the above range is satisfied, the capacity characteristics may be excellent and the life characteristics may be excellent. The above carbon-based negative electrode active material may be included in the negative electrode active material layer at 70 wt% to 99 wt%, preferably 75 wt% to 99 wt%, and more preferably 80 wt% to 98 wt%. When the above range is satisfied, the life characteristics of the battery can be improved while implementing sufficient capacity characteristics. Meanwhile, the negative electrode active material layer may optionally further include a negative electrode conductive material and a negative electrode binder in addition to the negative electrode active material. The above negative electrode conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without special restrictions. The negative electrode conductive material may include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, or carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, or silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one of these may be used alone or a mixture of two or more may be used. The negative electrode conductive material may typically be included in an amount of 1 wt% to 30 wt%, 1 wt% to 20 wt%, or 1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. The above negative electrode binder serves to improve adhesion between negative electrode active material particles and adhesion between the negative electrode active material and the negative electrode current collector. The above negative electrode binder may be selected from the group consisting of polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof may be used. The above negative electrode binder may be included in an amount of 1 to 30 wt%, preferably 1 to 20 wt%, and more preferably 1 to 10 wt%, based on the total weight of the negative electrode active material layer. Meanwhile, at the cathode, the R n can be 0.6Ω or less. Specifically, the R n may be 0.6Ω or less, 0.58Ω or less, 0.56Ω or less, 0.54Ω or less, 0.52Ω or less, 0.5Ω or less, 0.2Ω or more, 0.22Ω or more, 0.24Ω or more, 0.26Ω or more, 0.28Ω or more, 0.3Ω or more, 0.32Ω or more, 0.34Ω or more, 0.36Ω or more, 0.38Ω or more, 0.4Ω or more, 0.42Ω or more, 0.44Ω or more, 0.46Ω or more, or 0.48Ω or more. For example, the R n can be 0.6Ω or less, 0.2Ω to 0.58Ω, 0.3Ω to 0.54Ω, or 0.44Ω to 0.5Ω. When the above range is satisfied, the imbalance of the resistance of the positive and negative electrodes can be suppressed. 3) Membrane Next, the separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. If it is a separator commonly used in lithium secondary batteries, it can be used without special restrictions. At this time, the separator can be interposed between the positive electrode and the negative electrode. As the above-mentioned separator, a 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, or a laminated structure of two or more layers thereof can be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. can be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength can be used. (2) Electrolyte The electrolyte according to the present invention comprises a lithium salt and an organic solvent. The lithium salt described above can be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. The lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. The concentration of the lithium salt may be within the range of 0.1 M to 5.0 M, or 0.1 M 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. The above organic solvent may include at least one of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent. The above cyclic carbonate-based organic solvent is a high-viscosity organic solvent, and may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate. In addition, the linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and representative examples thereof include at least one organic solvent selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate, and specifically, ethyl methyl carbonate (EMC) may be included. Specific examples of the linear ester organic solvent include at least one organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. The above cyclic ester organic solvent may include at least one organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. Preferably, the electrolyte according to the present invention may include ethylene carbonate and dimethyl carbonate as organic solvents. Meanwhile, in addition to the electrolyte components, the electrolyte may additionally contain other additives for the purposes 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, The present invention relates to a compound 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. The above 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 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 other additives exceeds 20 wt%, there is a possibility that side reactions may occur excessively in the electrolyte during charge and discharge of the battery. In particular, when the above SEI film-forming additives are added in excessive amounts, they may not be sufficiently decomposed at high temperatures and may exist as unreacted substances or in a precipitated state in the electrolyte at room temperature. Accordingly, side reactions that reduce the life or resistance characteristics of the secondary battery may occur. (3) Battery case The above battery case is for accommodating the electrode assembly and the electrolyte, and various battery cases known in the art, such as a cylindrical battery case, a square battery case, a pouch-type battery case, etc., can be used. The lithium secondary battery according to the present invention is useful in portable devices such as mobile phones, laptop computers, and digital cameras, and in electric vehicles such as hybrid electric vehicles (HEVs). In addition, a battery module or battery pack including the lithium secondary battery as a unit cell can be used as a power source for one or more medium- to large-sized devices among a power tool; an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system. The lithium secondary battery according to the present invention can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells. Examples of the above medium and large-sized devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems. Method for manufacturing lithium secondary battery Next, a method for manufacturing a lithium secondary battery according to the present invention will be described. Referring to FIG. 1, the method for manufacturing a lithium secondary battery according to the present invention includes a step (S1) of mixing a first cathode active material in distilled water, performing a first washing, and drying; a step (S2) of mixing a second cathode active material in distilled water, performing a second washing, and drying; a step (S3) of applying a cathode slurry containing the first cathode active material and the second cathode active material onto a cathode current collector to manufacture a cathode; a step (S4) of manufacturing an anode containing a silicon-based anode active material; and a step (S5) of manufacturing a lithium secondary battery containing the cathode, the anode, and an electrolyte; wherein the first washing is performed at a higher temperature than the second washing, and the average particle diameter (D) of the first cathode active material is 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is greater than the first cathode active material and the second cathode active material include single-particle particles, and the lithium secondary battery has an IRF (Interfacial Resistance Factor) value of 1 to 1.4 defined by the following Equation 1. [Formula 1] In the above formula 1, the R n [Ω] means the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, and the Rp [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode. Hereinafter, each step of the method for manufacturing a lithium secondary battery according to the present invention will be described in detail. (1) S1 stage: First cathode active material washing stage First, a step (S1 step) of mixing the first positive electrode active material in distilled water, washing it for the first time, and drying it is performed. The above first positive electrode active material includes single-particle particles. When the first positive electrode active material is a single-particle particle, since the single-particle particle size is large, the diffusion distance of lithium is long, so that the diffusion resistance increases, so that the positive electrode may have low efficiency. Therefore, when applying a silicon-based negative electrode active material, the efficiency can be balanced with the negative electrode. Accordingly, when applying a conventional silicon-based negative electrode active material, the loss of lithium ions due to irreversible capacity can be suppressed, and the occurrence of lithium precipitation on the surface of the negative electrode can be prevented or suppressed, so that the life characteristics of a lithium secondary battery applying the positive electrode according to the present invention can be improved. In addition, when applying the first positive electrode active material which is a single-particle particle, unlike when using a conventional sacrificial positive electrode material, the generation of lithium byproducts due to the sacrificial positive electrode material during charge and discharge can be prevented or suppressed, so that high-temperature storage characteristics and high-temperature life characteristics can be excellent. Since the first positive electrode active material is the same as described above, a detailed description is omitted. The above step S1 serves to control the interface resistance of the positive electrode within a specific range by performing the washing intensity of the first positive electrode active material higher than the washing intensity of the second positive electrode active material in the step S2 described below. Specifically, the first washing is performed at a higher temperature than the second washing. The above first washing is performed at 20° C. to 40° C., 25° C. to 35° C., or 27° C. to 38° C. When the first washing is performed at the above temperature, the interface resistance of the anode can be controlled within the desired range. In addition, the first washing may be performed by mixing the first cathode active material in an amount of 50 wt% to 70 wt%, 55 wt% to 65 wt%, or 57 wt% to 63 wt% based on the total weight of distilled water. In this case, the amount of residual lithium on the surface of the cathode active material may be reduced, thereby preventing deterioration of high-temperature durability. The drying can be performed at 60°C to 200°C, 70°C to 180°C, or 80°C to 160°C. (2) S2 stage: Second cathode active material washing stage Next, a step (S2 step) of mixing the second positive electrode active material in distilled water, performing a second washing, and drying is performed. The second positive electrode active material includes single-particle particles. When the second positive electrode active material is a single-particle particle, since the single-particle particle size is large, the diffusion distance of lithium is long, so that the diffusion resistance increases, so that the positive electrode may have low efficiency. Therefore, when applying a silicon-based negative electrode active material, the efficiency can be balanced with the negative electrode. Accordingly, when applying a silicon-based negative electrode active material, the loss of lithium ions due to irreversible capacity can be suppressed, and the occurrence of lithium precipitation on the surface of the negative electrode can be prevented or suppressed, so that the life characteristics of a lithium secondary battery applying the positive electrode according to the present invention can be improved. In addition, when applying a second positive electrode active material which is a single-particle particle, unlike when using a conventional sacrificial positive electrode material, the generation of lithium byproducts due to the sacrificial positive electrode material during charge and discharge can be prevented or suppressed, so that high-temperature storage characteristics and high-temperature life characteristics can be excellent. The average particle diameter (D) of the first positive electrode active material 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is larger than that. Since the above second positive electrode active material is the same as described above, a detailed description is omitted. The above S2 step is performed by lowering the washing intensity of the second positive electrode active material having a smaller particle size and larger specific surface area than the first positive electrode active material, thereby preventing deterioration of the high-temperature durability of the second positive electrode active material and controlling the interface resistance of the positive electrode within a specific range. The second washing can be performed at 3° C. to 18° C., 5° C. to 15° C., or 7° C. to 13° C. When the second washing is performed within the above range, the deterioration of high-temperature durability can be prevented or reduced while controlling the interfacial resistance of the positive electrode to a desired range. In addition, the second washing may be performed by mixing the second cathode active material in an amount of 65 wt% to 85 wt%, 70 wt% to 80 wt%, or 72 wt% to 78 wt% based on the total weight of distilled water. In this case, residual lithium on the surface of the cathode active material may be reduced, thereby preventing deterioration of high-temperature durability. The drying can be performed at 60°C to 200°C, 70°C to 180°C, or 80°C to 160°C. (3) S3 stage: Anode manufacturing stage Next, a step (step S3) of manufacturing a positive electrode is performed by applying a positive electrode slurry containing the first positive electrode active material and the second positive electrode active material onto a positive electrode current collector. First, a cathode slurry can be prepared by mixing the first cathode active material, the second cathode active material, and the solvent. At this time, since the first positive electrode active material and the second positive electrode active material are the same as described above, a detailed description is omitted. The above cathode slurry may optionally further include a cathode binder and / or a cathode conductive material. Since the above-mentioned positive electrode binder and positive electrode conductive material are the same as those described above, a detailed description is omitted. Meanwhile, the solvent used in the positive electrode slurry may be an aqueous solvent, an organic solvent, or a combination thereof. The aqueous solvent may include, for example, water, and the organic solvent may include at least one selected from the group consisting of N-methyl pyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dihydrolevoglucosenone (Cyrene), γ-valerolactone, dimethyl isosorbide (DMI), and methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate, and preferably, N-methyl pyrrolidone. Next, the positive electrode slurry may be applied to a positive electrode current collector to form a positive electrode active material layer. Specifically, the positive electrode may be manufactured by applying the positive electrode slurry to one or both sides of the positive electrode current collector, and then drying and rolling to form a positive electrode active material layer. Since the above-mentioned positive electrode collector is the same as described above, a detailed description is omitted. Meanwhile, the above coating can be performed continuously or discontinuously using various coating methods well known in the art, such as slot die coating, slide coating, curtain coating, etc. The drying can be performed at a temperature of 40°C to 180°C, 60°C to 160°C, or 70°C to 150°C. The above rolling can be performed by a roll press method that adjusts the thickness of the anode by adjusting the upper / lower gap of the roll, but is not limited thereto. (4) S4 Step: Cathode Manufacturing Step Next, a step (step S4) of manufacturing a negative electrode including a silicon-based negative electrode active material is performed. First, the above silicon-based negative electrode active material and solvent can be mixed to prepare a negative electrode slurry. At this time, since the silicon-based negative electrode active material is the same as described above, a detailed description is omitted. The above negative electrode slurry may further contain a carbon-based negative electrode active material. Since the above carbon-based negative electrode active material is the same as described above, a detailed description is omitted. The above cathode slurry may optionally further include a cathode binder and / or a cathode conductive material. Since the above negative electrode binder and negative electrode conductive material are the same as those described above, a detailed description is omitted. Meanwhile, the solvent used in the cathode slurry may be an aqueous solvent, an organic solvent, or a combination thereof. The aqueous solvent may include, for example, water, and the organic solvent may include at least one selected from the group consisting of N-methyl pyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dihydrolevoglucosenone (Cyrene), γ-valerolactone, dimethyl isosorbide (DMI), and methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate, and preferably, N-methyl pyrrolidone. Next, the negative electrode slurry may be applied to a negative electrode current collector to form a negative electrode active material layer. Specifically, the negative electrode may be manufactured by applying the negative electrode slurry to one side or both sides of the negative electrode current collector, and then drying and rolling to form a negative electrode active material layer. Since the above negative electrode collector is the same as described above, a detailed description is omitted. Meanwhile, the above coating can be performed continuously or discontinuously using various coating methods well known in the art, such as slot die coating, slide coating, curtain coating, etc. The drying can be performed at a temperature of 40°C to 180°C, 60°C to 160°C, or 70°C to 150°C. The above rolling can be performed by a roll press method that adjusts the thickness of the anode by adjusting the upper / lower gap of the roll, but is not limited thereto. (5) S5 Step: Manufacturing step of lithium secondary battery Next, a step (step S5) of manufacturing a lithium secondary battery including the positive electrode, the negative electrode, and the electrolyte is performed. First, an electrode assembly including the positive electrode and the negative electrode can be formed, and specifically, the positive electrode, the separator, and the negative electrode can be sequentially laminated to form an electrode assembly. The types of electrode assemblies may include, but are not limited to, stacked, jellyroll, and stack-and-folded. After this, the electrode assembly can be housed inside a battery case, the electrolyte can be injected, and the battery case can be sealed to manufacture a lithium secondary battery. The above sealing can be performed by heat welding or heat fusing the opened portion of the battery case. The above IRF value, R n and R pSince it is the same as described above, a detailed description is omitted. Since the above separator, electrode assembly, electrolyte, and battery case are the same as those described above, a detailed description is omitted. Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Example 1 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 8.6㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 30°C so that the solid content became 60 wt%, washed, dried, and then mixed with Co(OH)2. After that, a first positive electrode active material coated with Co was manufactured by heat treatment at 750°C for 5 hours. The first positive electrode active material contained 3 mol% of Co and had an average particle diameter (D 50) was confirmed to be 8.6㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 3.1㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 75 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 3.1㎛ and a single particle. <Polar manufacturing> The first positive electrode active material and the second positive electrode active material manufactured above were mixed in a weight ratio of 60:40 to manufacture a positive electrode material, and the positive electrode material, carbon black as a conductive material, and polyvinylidene fluoride (PVDF) as a binder were mixed in a weight ratio of 96:2:2 in an N-methylpyrrolidone solvent to manufacture a positive electrode slurry. The positive electrode slurry was applied to one surface of an aluminum current collector having a thickness of 20 μm, dried at 130°C, and then rolled to manufacture a positive electrode having a thickness of 70 μm. <Lithium secondary battery manufacturing> A negative electrode slurry was prepared by mixing a negative electrode active material of SiO:artificial graphite in a weight ratio of 5:95, a conductive material of carbon black, a binder of SBR, and a thickener of CMC in a weight ratio of 95.6:1.0:2.3:1.1 in distilled water. The negative electrode slurry was applied to one surface of a copper current collector having a thickness of 12 μm, dried at 130°C, and then rolled to prepare a negative electrode. (Slurry solid content: 50 wt% based on the total weight of the negative electrode slurry) An electrode assembly was manufactured by interposing a porous polyethylene separator between each of the positive and negative electrodes manufactured as described above, and then positioned inside a battery case, and an electrolyte was injected to manufacture a lithium secondary battery. At this time, an electrolyte solution was used in which 1.0 M LiPF6 was dissolved in an organic solvent mixed with ethylene carbonate (EC): ethyl methyl carbonate (EMC) in a volume ratio of 3:7. Example 2 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 8.4㎛, and Ni0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 25°C so that the solid content became 60 wt%, washed, dried, and then Co(OH)2 was mixed. Thereafter, a first positive electrode active material coated with Co was manufactured by heat-treating at 750°C for 5 hours. The first positive electrode active material contained 3 mol% of Co and had an average particle size (D 50 ) was confirmed to be 8.4㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 3.3㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 15°C so that the solid content became 75 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 3.3㎛ and a single particle. <Polar manufacturing> A positive electrode was manufactured using the same method as above, except that the first positive electrode active material and the second positive electrode active material were used. <Lithium secondary battery manufacturing> A lithium secondary battery was manufactured using the same method as in Example 1, except that the positive electrode manufactured above was used. Example 3 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 8.1㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 30°C so that the solid content became 60 wt%, washed, dried, and then Co(OH)2 was mixed. Thereafter, heat treatment was performed at 750°C for 5 hours to manufacture a first positive electrode active material coated with Co. The first positive electrode active material contained 2.5 mol% of Co and had an average particle size (D 50 ) was confirmed to be 8.1㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 3.5㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 75 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1.5 mol% of Co and had an average particle size (D 50 ) was confirmed to be 3.5㎛ and a single particle. <Polar manufacturing> A positive electrode was manufactured using the same method as above, except that the first positive electrode active material and the second positive electrode active material were used. <Lithium secondary battery manufacturing> A lithium secondary battery was manufactured using the same method as in Example 1, except that the positive electrode manufactured above was used. Comparative Example 1 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 7.2㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 75 wt%, washed, dried, and then Co(OH)2 was mixed. Thereafter, a first positive electrode active material coated with Co was manufactured by heat-treating at 750°C for 5 hours. The first positive electrode active material contained 3 mol% of Co and had an average particle size (D 50 ) was confirmed to be 7.2㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 2.5㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 75 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 2.5㎛ and a single particle. <Polar manufacturing> A positive electrode was manufactured using the same method as above, except that the first positive electrode active material and the second positive electrode active material were used. <Lithium secondary battery manufacturing> A lithium secondary battery was manufactured using the same method as in Example 1, except that the positive electrode manufactured above was used. Comparative Example 2 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 7.7㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 30°C so that the solid content became 60 wt%, washed, dried, and then Co(OH)2 was mixed. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a first positive electrode active material coated with Co. The first positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 7.7㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 2.9㎛, and Ni 0.83 Co0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 70 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 2.9㎛ and a single particle. <Polar manufacturing> A positive electrode was manufactured using the same method as above, except that the first positive electrode active material and the second positive electrode active material were used. <Lithium secondary battery manufacturing> A lithium secondary battery was manufactured using the same method as in Example 1, except that the positive electrode manufactured above was used. Comparative Example 3 <Manufacture of the first cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 8.5㎛, and Ni 0.83 Co 0.07 Mn 0.1A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A first lithium transition metal oxide represented by O2 was prepared. Then, the first lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 75 wt%, washed, dried, and then Co(OH)2 was mixed. Thereafter, a first positive electrode active material coated with Co was manufactured by heat-treating at 750°C for 5 hours. The first positive electrode active material contained 3 mol% of Co and had an average particle size (D 50 ) was confirmed to be 8.5㎛ and a single particle. <Manufacturing of the second cathode active material> A transition metal aqueous solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in distilled water in an amount such that the molar ratio of nickel:cobalt:manganese was 83:7:10. Next, deionized water is added to the reactor, nitrogen gas is purged into the reactor to remove dissolved oxygen in the water, and the inside of the reactor is made into a non-oxidizing atmosphere. Then, NaOH is added to proceed with a co-precipitation reaction, thereby obtaining an average particle size (D 50 ) is 3.0㎛, and Ni 0.83 Co 0.07 Mn 0.1 A precursor represented by (OH)2 was prepared. The above precursor and LiOH were mixed in a ratio of 1:1.05, and Al was mixed as a doping element and calcined at 910°C for 16 hours to obtain Li[Ni 0.81 Co 0.07 Mn 0.10 Al 0.02 ]A second lithium transition metal oxide represented by O2 was prepared. Then, the second lithium transition metal oxide was mixed in distilled water at 10°C so that the solid content became 70 wt%, washed, dried, and then mixed with Co(OH)2. After that, a heat treatment was performed at 750°C for 5 hours to manufacture a second positive electrode active material coated with Co. The second positive electrode active material contained 1 mol% of Co and had an average particle size (D 50 ) was confirmed to be 3.0㎛ and a single particle. <Polar manufacturing> A positive electrode was manufactured using the same method as above, except that the first positive electrode active material and the second positive electrode active material were used. <Lithium secondary battery manufacturing> A lithium secondary battery was manufactured using the same method as in Example 1, except that the positive electrode manufactured above was used. Experimental Example 1 - IRF Value Measurement The IRF value defined by Equation 1 below was measured for each lithium secondary battery manufactured in Examples 1 to 3 and Comparative Examples 1 to 3. The results are shown in Table 1 below. [Formula 1] In the above formula 1, the R n [Ω] means the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, and the R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode. (1) Interfacial resistance of the anode (R) p ) measurement Each of the lithium secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 was charged under CC / CV, 0.1 C, 4.2 V, 0.05 C cut conditions at 25°C, and discharged under CC, 0.1 C, 3.0 V conditions, which was counted as 1 cycle, and 100 cycles were performed. Then, each lithium secondary battery was charged to SOC 50% or SOC 10%, and the positive electrode interfacial resistance at SOC 50% and SOC 10% of each lithium secondary battery was measured using a Biologic VMP3 device (100 kHz to 10 mHz range, 25°C conditions). (2) Interfacial resistance of the cathode (R) n ) measurement Each of the lithium secondary batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 was charged under CC / CV, 0.1 C, 0.05 V, 0.05 C cut conditions at 25°C, and discharged under CC, 0.1 C, 1.5 V conditions, which was counted as 1 cycle, and then 100 cycles were performed. Then, each lithium secondary battery was charged to SOC 50% or SOC 10%, and the cathode interface resistance at SOC 50% and SOC 10% of each lithium secondary battery was measured using a Biologic VMP3 device (100 kHz to 10 mHz range, 25°C conditions). 100 cycle positive interface resistance [Ω] 100 cycle negative interface resistance [Ω] IRF Example 10.586 0.490 1.195918 Example 20.538 0.506 1.063241 Example 30.642 0.589 1.089983 Comparative Example 10.28 10.592 0.474662 Comparative Example 20.877 0.6111 435352 Comparative Example 30.377 0.673 0.560 178 Referring to Table 1 above, it can be confirmed that the lithium secondary batteries manufactured in Examples 1 to 3 satisfy the IRF value of 1 to 1.4, but the lithium secondary batteries manufactured in Comparative Examples 1 to 3 do not satisfy the IRF value of 1 to 1.4, such as being less than 1 or exceeding 1.4. Experimental Example 2 - Evaluation of High Temperature Life Characteristics The lithium secondary batteries manufactured in the above Examples 1 to 3 and Comparative Examples 1 to 3 were charged to 4.2 V under CC / CV, 0.5 C conditions, 0.05 C cut conditions at 45°C using an electrochemical charger / discharger, and then discharged to 3.0 V under CC, 1.0 C conditions, which is considered one cycle, to perform 100 charge / discharge cycles. (1) Capacity maintenance rate The capacity retention rate is calculated using the formula below, and the results are shown in Table 2 below. Capacity retention rate (%) = {(discharge capacity after 100 cycles / discharge capacity after 1 cycle)} Х 100 (2) Resistance increase rate After one cycle of charge and discharge, the discharge capacity after one cycle was measured using an electrochemical charger / discharger, the SOC was adjusted to 50%, and then a 2.5C pulse was applied for 10 seconds, and the initial resistance was calculated through the difference between the voltage before and after pulse application. After 100 cycles of charge and discharge, the resistance after 100 cycles was calculated using the same method as above, and the resistance increase rate was calculated using the equation below, and the results are shown in Table 2 below. Resistance increase rate (%) = (resistance after 100 cycles - initial resistance) / initial resistance Х 100 Capacity retention rate (%) Resistance increase rate (%) Example 198.9 11.3 Example 297.4 16.3 Example 396.9 18.1 Comparative example 193.2 43.5 Comparative example 294.5 39.7 Comparative example 392.3 48.9 Referring to Table 2 above, it can be confirmed that the lithium secondary batteries manufactured in Examples 1 to 3 have a higher capacity retention rate at 45°C and a lower resistance increase rate at 45°C than the lithium secondary batteries manufactured in Comparative Examples 1 to 3. Through this, it can be understood that the lithium secondary batteries manufactured in Examples 1 to 3 employing the cathode active material of the present invention have superior high-temperature life characteristics compared to the lithium secondary batteries that do not employ the cathode active material of the present invention. Although the above has been described with reference to the embodiments of the present disclosure, it will be understood by those skilled in the art or having common knowledge in the art that various modifications and changes can be made to the various embodiments of the present disclosure without departing from the technical scope of the various embodiments of the present disclosure set forth in the claims to be described below. Therefore, the technical scope of the various embodiments of the present disclosure should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims

1. A lithium secondary battery comprising: a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and an electrolyte; The above anode has an average particle diameter (D 50 ) includes different first positive electrode active materials and second positive electrode active materials, The average particle diameter (D) of the first positive electrode active material 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is larger than The above first positive electrode active material and the above second positive electrode active material include single particle-type particles, The above negative electrode contains a silicon-based negative electrode active material, The above lithium secondary battery is a lithium secondary battery having an IRF (Interfacial Resistance Factor) value of 1 to 1.4, as defined by the following Equation 1. [Formula 1] In the above equation 1, Above R n [Ω] refers to the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, Above R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode.

2. In paragraph 1, A lithium secondary battery, wherein the first positive electrode active material comprises a first lithium transition metal oxide represented by the following chemical formula 1. [Chemical Formula 1] Li 1+a1 Ni x1 Co y1 Mr z1 Al w1 M 1 v1 O2 In the above chemical formula 1, 0≤a1≤0.3, 0.82≤x1<1.0, 0 <y1≤0.2, 0<z1≤0.2, 0<w1≤0.2, 0≤v1≤0.1이고, M 1 is a doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

3. In paragraph 1, A lithium secondary battery, wherein the second positive electrode active material comprises a second lithium transition metal oxide represented by the following chemical formula 2. [Chemical formula 2] Li 1+a2 Ni x2 Co y2 Mr z2 Al w2 M 2 v2 O2 In the above chemical formula 2, 0≤a2≤0.3, 0.82≤x2<1.0, 0 <y2≤0.2, 0<z2≤0.2, 0<w2≤0.2, 0≤v2≤0.1이고, M 2 is a doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo.

4. In paragraph 1, Above R n A lithium secondary battery having a resistance of 0.6Ω or less.

5. In paragraph 1, The average particle diameter (D) of the first positive electrode active material 50 ) is a lithium secondary battery having a diameter of 6㎛ to 12㎛.

6. In paragraph 1, The average particle diameter (D) of the second positive electrode active material 50 ) is a lithium secondary battery having a particle size of 1.5㎛ to 5㎛.

7. In paragraph 1, A lithium secondary battery, wherein the first cathode active material comprises a first lithium transition metal oxide and a first coating layer positioned on the surface of the first lithium transition metal oxide particles and containing 1.5 mol% to 5 mol% of cobalt (Co).

8. In paragraph 1, A lithium secondary battery, wherein the second cathode active material comprises a second lithium transition metal oxide and a second coating layer positioned on the surface of the second lithium transition metal oxide particles and containing 0.2 mol% to 2.5 mol% of cobalt (Co).

9. In paragraph 1, The first cathode active material comprises a first lithium transition metal oxide, and comprises a first coating layer comprising cobalt (Co) on the surface of the first transition metal oxide particles, The second cathode active material comprises a second lithium transition metal oxide, and comprises a second coating layer comprising cobalt (Co) on the surface of the second lithium transition metal oxide particles. A lithium secondary battery, wherein the first coating layer contains a larger amount of cobalt than the second coating layer.

10. In paragraph 1, A lithium secondary battery, wherein the first positive electrode active material and the second positive electrode active material are included in a weight ratio of 80:20 to 40:

60.

11. In paragraph 1, The above negative electrode comprises a carbon-based negative electrode active material, A lithium secondary battery, wherein the silicon-based negative electrode active material and the carbon-based negative electrode active material are included in a weight ratio of 1:99 to 30:

70.

12. Step (S1) of mixing the first positive electrode active material in distilled water, washing it with water, and drying it; Step (S2) of mixing the second cathode active material in distilled water, washing it a second time, and drying it; A step (S3) of manufacturing a positive electrode by applying a positive electrode slurry containing the first positive electrode active material and the second positive electrode active material onto a positive electrode current collector; Step (S4) of manufacturing a negative electrode including a silicon-based negative electrode active material; and A step (S5) of manufacturing a lithium secondary battery including the positive electrode, the negative electrode, and the electrolyte; The above first washing is performed at a higher temperature than the above second washing, The average particle diameter (D) of the first positive electrode active material 50 ) is the average particle diameter (D) of the second positive electrode active material. 50 ) is greater than The above first positive electrode active material and the above second positive electrode active material contain single particle-type particles, A method for manufacturing a lithium secondary battery, wherein the lithium secondary battery has an IRF (Interfacial Resistance Factor) value of 1 to 1.4, as defined by the following Equation 1. [Formula 1] In the above equation 1, Above R n [Ω] refers to the interfacial resistance of the negative electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above negative electrode, Above R p [Ω] refers to the interfacial resistance of the positive electrode measured after performing 100 charge / discharge cycles on a lithium secondary battery manufactured using the above positive electrode.

13. In paragraph 12, A method for manufacturing a lithium secondary battery, wherein the first washing is performed at a temperature of 20°C to 40°C.

14. In paragraph 12, A method for manufacturing a lithium secondary battery, wherein the second washing is performed at 3°C ​​to 18°C.

15. In paragraph 12, A method for manufacturing a lithium secondary battery, wherein the first washing is performed by mixing the first cathode active material in an amount of 50 to 70 wt% based on the total weight of distilled water.

16. In paragraph 12, A method for manufacturing a lithium secondary battery, wherein the second washing is performed by mixing the second cathode active material in an amount of 65 to 85 wt% based on the total weight of distilled water.

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