Cathode material and lithium secondary battery comprising same

Abstract

The present invention relates to a cathode material comprising: a first cathode active material comprising a lithium manganese-based oxide having a spinel structure; and a second cathode active material having a layered structure and comprising a lithium nickel-based oxide including nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al), wherein the lithium manganese-based oxide and the lithium nickel-based oxide are single-particle particles.

Description

Cathode material and lithium secondary battery containing the same Cross-citation with related applications This application claims the benefit of priority from Korean Patent Application No. 10-2023-0190076, filed December 22, 2023, the entire contents of which are incorporated herein by reference. Technical field The present invention relates to a cathode material and a lithium secondary battery including the same, and more specifically, to a cathode material having excellent thermal stability and capacity characteristics while reducing manganese dissolution at high temperatures, and a lithium secondary battery including the cathode active material. Recently, development of large-volume, large-capacity can-type batteries is in progress to further increase the capacity of batteries for electric vehicles. In the case of small cylindrical batteries that were commonly used in the past, that is, cylindrical batteries with form factors of 1865 or 2170, resistance or heat generation did not have a serious effect on battery performance because the capacity was small. However, if the specifications of the conventional small cylindrical batteries are applied to large batteries as they are, serious problems may occur in battery safety. As the size of the battery increases, the amount of heat and gas generated inside the battery also increases. This heat and gas may cause the temperature and pressure inside the battery to rise, which may cause the battery to ignite or explode. To prevent this, the heat and gas inside the battery must be appropriately discharged to the outside. To this end, the cross-sectional area of ​​the battery, which acts as a passage for dissipating heat outside the battery, must increase in proportion to the increase in volume. However, since the increase in cross-sectional area is usually not enough to increase the volume, as the battery becomes larger, the amount of heat generated inside the battery increases, which may increase the risk of explosion and cause problems such as reduced output. In addition, when rapid charging is performed at high voltage, the battery may ignite due to the generation of a large amount of heat around the electrode tabs in a short period of time. On the other hand, lithium manganese oxides with spinel structure such as LiMn2O4 have the advantages of excellent thermal stability and low price, but have small capacity and Mn loss during charge and discharge. 3+ There is a problem that structural deformation (Jahn-Teller distortion) occurs due to the lithium secondary battery, and the performance of the lithium secondary battery rapidly deteriorates due to Mn dissolution caused by HF formed by a reaction with the electrolyte at high temperatures. Therefore, there is a need to develop a lithium secondary battery that has excellent thermal stability and capacity characteristics, and excellent life characteristics due to low manganese dissolution at high temperatures. The present invention is intended to solve the above problems, and to provide a cathode material including a lithium manganese oxide having a spinel structure, while reducing manganese release at high temperatures. In addition, the present invention is intended to provide a lithium secondary battery having excellent thermal stability, high-temperature life characteristics, and capacity characteristics, including the cathode material according to the present invention. [1] The present invention provides a cathode material comprising a first cathode active material including a lithium manganese oxide having a spinel structure; and a second cathode active material including a lithium nickel oxide having a layered structure and including nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al), wherein the lithium manganese oxide and the lithium nickel oxide are single-particle particles. [2] The present invention provides a cathode material, wherein, in the above [1], the lithium nickel-based oxide contains nickel at 90 mol% or more among all metals excluding lithium. [3] The present invention provides a cathode material in which the weight ratio of the first cathode active material and the second cathode active material in [1] or [2] is 75:25 to 50:50. [4] The present invention, in at least one of the above [1] to [3], the average particle diameter (D) of the first positive electrode active material and the second positive electrode active material50 ) provides a cathode material having a ratio of 5:1 to 1.5:1. [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 cathode material having a diameter of 5 μm to 20 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 cathode material having a diameter of 1 μm to 10 μm. [7] The present invention provides a cathode material, wherein in at least one of the above [1] to [6], the lithium manganese oxide has a composition represented by the following [chemical formula 1]. [Chemical Formula 1] Li 1+a1 Mn 2-x1 M 1 x1 O 4-y1 A y1 In the above chemical formula 1, the M 1 is at least one doping element selected from the group consisting of Al, Li, Mg, Zn, B, W, Ni, Co, Fe, Cr, V, Ru, Cu, Cd, Ag, Y, Sc, Ga, In, As, Sb, Pt, Au and Si, and A is at least one element selected from the group consisting of F, Cl, Br, I, At and S, and 0≤a1≤0.4, 0 <x1≤0.5, 0≤y1≤0.1이다. [8] The present invention, in at least one of the above [1] to [7], the lithium manganese oxide is M 1 It may be included in an amount of 0.5 wt% to 3 wt% based on the total weight of the lithium manganese oxide. [9] The present invention provides a cathode material, which comprises a first coating layer positioned on the surface of the lithium manganese oxide in at least one of the above [1] to [8], and wherein the first coating layer comprises at least one element selected from the group consisting of Al, Ti, W, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb. Mo, Sr, Sb, Bi, Si, S and B.

[0010] The present invention provides a cathode material, wherein, in the above [9], the first coating layer is included in an amount of 0.05 wt% to 0.3 wt% based on the total weight of the first cathode active material.

[0011] The present invention provides a cathode material, wherein in at least one of the above [1] to

[0010] , the lithium nickel-based oxide has a composition represented by the following [chemical formula 2]. [Chemical formula 2] Li a2 [Ni x2 Co y2 Mn z2 Al w2 M 2 v2 ]O2 In the above chemical formula 2, M 2 is 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, and 0.8≤a2≤1.2, 0.9≤x2<1, 0 <y2≤0.2, 0<z2≤0.2, 0<w2≤0.2, 0≤v2≤0.1이다.

[0012] The present invention provides a cathode material, which comprises a second coating layer positioned on the surface of the lithium nickel-based oxide in at least one of the above [1] to

[0011] , and wherein the second coating layer comprises at least one element selected from the group consisting of Ti, W, B, F, P, Mg, Ni, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si, S, Co and Al.

[0013] The present invention provides a cathode material, wherein, in the above

[0012] , the second coating layer is included in an amount of 0.01 wt% to 5 wt% based on the total weight of the second cathode active material.

[0014] The present invention provides a lithium secondary battery comprising: an electrode assembly including a cathode material according to any one of the above [1] to

[0013] , a cathode, and a separator interposed between the cathode and the cathode; an electrolyte; and a battery case accommodating the electrode assembly and the electrolyte.

[0015] The present invention provides a lithium secondary battery, wherein the battery case in the above

[0014] is a cylindrical battery case.

[0016] The present invention provides a lithium secondary battery, wherein, in the above

[0014] or

[0015] , the ratio of the diameter (T) to the height (H) (form factor ratio) of the lithium secondary battery is 0.4 or more.

[0017] The present invention provides a lithium secondary battery, wherein, in at least one of the above

[0014] to

[0016] , the lithium secondary battery includes a non-conductive portion in which an active material layer is not formed on at least a portion of the positive electrode and the negative electrode, and the non-conductive portion of the positive electrode and the non-conductive portion of the negative electrode are defined as electrode tabs. According to the present invention, by mixing together a lithium manganese-based oxide having a spinel structure and a lithium nickel-based oxide containing nickel, cobalt, manganese, and aluminum, and using a cathode material in which both the lithium manganese-based oxide and the lithium nickel-based oxide are single-particle particles, the manganese elution amount at high temperatures can be significantly reduced. Accordingly, the cathode material according to the present invention can have superior high-temperature storage characteristics and high-temperature cycle characteristics compared to conventional cathodes. In addition, the cathode material according to the present invention improves the thermal stability of a lithium secondary battery by including a lithium manganese oxide having a spinel structure, and at the same time, it can realize high energy density and high capacity characteristics by including a lithium nickel oxide having excellent capacity characteristics. Figure 1 is a drawing showing a state of lamination before winding of an electrode assembly according to the present invention. FIG. 2 is a cross-sectional view showing the structure of an electrode of an electrode assembly according to one embodiment of the present invention. FIG. 3 is a drawing for explaining the structure of an electrode assembly according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure of a lithium secondary battery according to one embodiment of the present invention. FIG. 5 is a cross-sectional view showing the structure of a lithium secondary battery according to another embodiment of the present invention. Figure 6 is a drawing for explaining a battery pack according to the present invention. Figure 7 is a surface image at 3,000x magnification of lithium manganese oxide manufactured in Manufacturing Example 1 of the present invention, obtained using a scanning electron microscope. Figure 8 is a surface image at 5,000 times magnification of lithium nickel oxide manufactured in Manufacturing Example 3 of the present invention, obtained using a scanning electron microscope. Figure 9 is a surface image at 5,000 times magnification of lithium nickel oxide manufactured in Manufacturing Example 4 of the present invention, obtained using a scanning electron microscope. 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 “comprise,” “include,” or “have,” etc., are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the present invention, the term "single particle" refers to a particle composed of 30 or fewer nodules, and is a concept that includes single particles and pseudo-single particles. "Single particle" refers to a particle composed of one single nodule, and "pseudo-single particle" refers to a particle that is a composite formed of 30 or fewer nodules. In the present invention, “nodule” means a particle unit body constituting a single particle and a quasi-single particle, and the nodule may be a single crystal lacking a crystalline grain boundary, or a polycrystal in which no grain boundary exists in appearance when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope (SEM). In the present invention, "secondary particle" means a particle formed by agglomeration of tens to hundreds of primary particles. More specifically, the secondary particle is an agglomerate of 40 or more primary particles. The expression “particle” used in the present invention may include 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, the "average particle size D50" means a particle size at 50% of the volume cumulative particle size distribution of the positive electrode active material powder, and can be measured using a laser diffraction method. For example, after dispersing the positive electrode active material powder in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), and after irradiating the device with ultrasonic waves of about 28 kHz with an output of 60 W, a volume cumulative particle size distribution graph is obtained, and then the particle size corresponding to 50% of the volume cumulative amount is measured. The inventors of the present invention have conducted repeated studies to develop a cathode material having excellent thermal stability, high-temperature storage characteristics, and excellent cycle characteristics. As a result, they have found that when a lithium manganese oxide having a single-particle spinel structure and a lithium nickel oxide having a single-particle structure are used together, the manganese elution amount at high temperatures is significantly reduced, so that high-temperature storage characteristics and high-temperature cycle characteristics can be excellent, while thermal stability and capacity characteristics can be improved, thereby completing the present invention. Hereinafter, the present invention will be described in detail. The cathode material and / or lithium secondary battery according to the present invention comprises at least one of the configurations disclosed below, and may comprise any combination between technically possible configurations among the configurations below. Bipolar material A cathode material according to the present invention comprises a first cathode active material including a lithium manganese oxide having a spinel structure; and a second cathode active material including a lithium nickel oxide having a layered structure and including nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al), wherein the lithium manganese oxide and the lithium nickel oxide are single-particle particles. In general, when a lithium manganese oxide having a spinel structure is used as a cathode material for a lithium secondary battery, the lithium secondary battery using the lithium manganese oxide has the advantage of excellent thermal stability and reduced cost. However, when the lithium manganese oxide is used alone, there is a disadvantage in that there is a limit to the capacity characteristics of the lithium secondary battery. In addition, in the case of the lithium manganese oxide having the spinel structure, when the oxidation number of manganese becomes +3.5 or lower while repeating charge and discharge, high-spin d 4 Mn with electronic configuration 3+ Due to this, a structural deformation phenomenon (Jahn-Teller distortion) may occur. Accordingly, the structure of the lithium manganese oxide of the spinel structure may become unstable. In particular, at a high temperature of 50℃ or higher, the Mn 3+ Mn is formed through a disproportionation reaction according to the following reaction formula A. 2+ Can form ions, and the above Mn 2+ There is a problem that ions are eluted into the electrolyte. In addition, when charging and discharging are repeated in a high-voltage environment, the LiPF6 additive in the electrolyte decomposes to produce hydrofluoric acid (HF). As manganese eluted by the HF accelerates, the deterioration of the cathode material is aggravated, resulting in further deterioration of the performance of the lithium secondary battery. The present inventors have conducted repeated studies to solve the above problems and have found that when a lithium manganese-based oxide having a spinel structure and the lithium nickel-cobalt-manganese-aluminum oxide are mixed and the lithium manganese-based oxide and the lithium nickel-cobalt-manganese-aluminum oxide are used in the form of single particles, the amount of manganese dissolution at high temperatures is significantly reduced, thereby improving the life characteristics and also improving the capacity characteristics. On the other hand, according to the research of the present inventors, even when a lithium manganese-based oxide and a lithium nickel-cobalt-manganese-aluminum oxide are mixed and used, the effect of reducing high-temperature manganese dissolution is minimal when one of the two particle forms is a secondary particle or when the lithium nickel-based oxide is not a quaternary oxide containing nickel, cobalt, manganese and aluminum. Meanwhile, in the present invention, the weight ratio of the first positive electrode active material and the second positive electrode active material may be 75:25 to 50:50, preferably 70:30 to 52:48, more preferably 65:35 to 55:45, and even more preferably 62:38 to 57:43. When the above range is satisfied, thermal stability, high-temperature life characteristics, capacity characteristics, and resistance characteristics can be excellently implemented at the same time. The above cathode material has an average particle diameter (D 50 ) may include different first and second positive electrode active materials. Preferably, 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 ) can be greater than that. In this case, manganese dissolution from the first cathode active material can be more effectively suppressed, and as a result, the high-temperature storage characteristics and high-temperature cycle characteristics of the battery can be further improved. In addition, in the rolling process of the electrode, the small-particle-diameter second cathode active material is filled in the pores of the large-particle-diameter first cathode active material, so that the cathode density increases, and thus a high energy density can be implemented, so that excellent capacity characteristics can be achieved. Specifically, the average particle diameter (D) of the first positive electrode active material and the second positive electrode active material 50 ) may be 5:1 to 1.5:1, preferably 4.5:1 to 1.7:1, more preferably 4:1 to 2:1, even more preferably 3.5:1 to 2:1, even more preferably 3:1 to 2:1. When the above range is satisfied, the high temperature life characteristics and capacity characteristics can be further improved. Hereinafter, the first positive electrode active material and the second positive electrode active material will be described in detail. (1) First positive electrode active material The above first positive electrode active material includes a lithium manganese oxide having a spinel structure. When a lithium manganese oxide having a spinel structure is included, it has the advantage of being inexpensive, cost-effective, non-toxic, and capable of realizing a cathode active material with excellent electrochemical and thermal stability. The above lithium manganese oxide may have a composition represented by the following [chemical formula 1]. [Chemical Formula 1] Li 1+a1 Mn 2-x1 M 1 x1 O 4-y1 A y1 In the above chemical formula 1, the M 1 is a doping element substituted for a manganese site in a lithium manganese oxide, and specifically, may be at least one doping element selected from the group consisting of Al, Li, Mg, Zn, B, W, Ni, Co, Fe, Cr, V, Ru, Cu, Cd, Ag, Y, Sc, Ga, In, As, Sb, Pt, Au and Si, and preferably, the M 1 may be at least one doping element selected from the group consisting of Al, B, Li, Mg, and Zn. The above A is an element substituted for an oxygen site in a lithium manganese oxide, and may be at least one element selected from the group consisting of F, Cl, Br, I, At, and S. Meanwhile, the above 1+a1 represents the molar ratio of lithium in the lithium manganese oxide, and may be 0≤a1≤0.4, preferably 0.1≤a1≤0.4, and more preferably 0.25≤a1≤0.35. The above x1 is a doping element M in lithium manganese oxide. 1 It represents the molar ratio of 0 <x1≤0.5, 바람직하게는 0.03≤x1≤0.25일 수 있다. M 1 When the molar ratio x1 satisfies the above range, a structurally stable cathode active material can be obtained while minimizing capacity degradation of a lithium secondary battery including the lithium manganese oxide. The above y1 represents the molar ratio of element A in lithium manganese oxide, and may be 0≤y1≤0.1, preferably 0.01≤y1≤0.05. The lithium manganese oxide represented by the chemical formula 1 above is a doping element M with a low oxidation number. 1 The average oxidation number of Mn ions increases relatively, including Mn ions, and this causes Mn to increase during charge and discharge. 3+ It is possible to minimize structural deformation (Jahn-Teller distortion) due to high temperature, thereby reducing the occurrence of manganese (Mn) dissolution at high temperatures. The above lithium manganese oxide is M 1 The lithium manganese oxide may be included in an amount of 0.5 wt% to 3 wt% based on the total weight of the lithium manganese oxide, preferably 0.8 wt% to 2.5 wt%, more preferably 1.0 wt% to 2.0 wt%, and even more preferably 1.3 wt% to 1.6 wt%. When the above range is satisfied, Mn during charge and discharge 3+By minimizing structural deformation caused by manganese, the occurrence of manganese dissolution at high temperatures can be reduced, while excellent thermal stability can be achieved by including Mn in a sufficient molar ratio in lithium manganese oxide. The lithium manganese oxide may include a first coating layer, and the first coating layer may be located on a surface of the lithium manganese oxide. The above first coating layer can block contact between the lithium manganese oxide and the electrolyte, thereby suppressing gas generation during charging and discharging, and preventing manganese (Mn) from being eluted at high temperatures. The first coating layer may include at least one element (hereinafter referred to as “coating element”) selected from the group consisting of Al, Ti, W, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb. Mo, Sr, Sb, Bi, Si, S and B, preferably at least one element selected from the group consisting of Al, Ti, Zn, W and B, and more preferably at least one element selected from the group consisting of B, W and Al. When the first coating layer includes the coating element, the phenomenon of manganese being eluted by HF formed in a side reaction with the electrolyte can be more effectively suppressed. Meanwhile, the first coating layer may be formed continuously or discontinuously on the surface of the lithium manganese oxide represented by the above-described [chemical formula 1]. For example, the first coating layer may be formed in a form in which particles containing the coating elements are discontinuously attached to the surface of a lithium manganese oxide. At this time, the particles containing the coating elements are, for example, ZnO, Al2O3, TiO2, WO. 3,It can be an oxide particle such as MgO, CaO, B2O3, NbO2, SrO, CrO, Mo2O5, Bi2O3, SiO. When the oxide particles such as the above exist on the surface of the lithium manganese oxide particles, as shown in the following reaction formula 1, the oxide particles capture and decompose HF formed by the reaction with the electrolyte, so that the Mn dissolution by HF is further suppressed. [Reaction Formula 1] B2O3+6HF → 2BF3+3H2O ZnO +2HF → ZnF2+H2O Al2O3+ 6HF → 2AlF3+3H2O Alternatively, the first coating layer may be formed in the form of a film containing the coating elements on the surface of the lithium manganese oxide. When the first coating layer is formed in the form of a film, the effect of blocking contact between the electrolyte and the lithium manganese oxide and the effect of inhibiting manganese dissolution are more excellent. When the first coating layer in the form of a film as described above is formed on the surface of the lithium manganese oxide particles, contact with the electrolyte is blocked by the first coating layer, thereby further inhibiting side reactions with the electrolyte and gas generation. The first coating layer may be included in an amount of 0.05 wt% to 0.3 wt% based on the total weight of the first positive electrode active material, preferably 0.07 wt% to 0.25 wt%, more preferably 0.08 wt% to 0.2 wt%, and even more preferably 0.09 wt% to 0.13 wt%. When the above range is satisfied, the increase in resistance of the positive electrode due to the first coating layer can be minimized while effectively blocking contact between the electrolyte and the lithium manganese oxide, thereby reducing manganese dissolution at high temperatures. Meanwhile, the first coating layer may be formed in an area corresponding to 50 to 100% of the total surface area of ​​the lithium manganese oxide, preferably 80 to 100%, more preferably 90 to 100%. When the first coating layer formation area satisfies the above range, contact between the electrolyte and the lithium manganese oxide can be effectively blocked. In addition, the lithium manganese oxide is a single particle. Previously, in the case of lithium manganese oxide in the form of secondary particles in which tens to hundreds of primary particles are aggregated, the primary particles are likely to break during the rolling process during the manufacture of the positive electrode, and cracks may occur inside the particles during the charge and discharge process. Accordingly, since the contact area with the electrolyte increases, the amount of gas generated due to a side reaction with the electrolyte may increase, and manganese dissolution occurs more due to HF formed by the reaction with the electrolyte at high temperatures, which further increases the degradation of the active material, and there is a problem of reduced high-temperature life characteristics. Accordingly, the cathode active material according to the present invention includes a first cathode active material including a lithium manganese oxide which is a single particle, so that the particle strength is higher than that of a conventional lithium manganese oxide in the form of secondary particles, so that the particle breakage is less during rolling, and since the number of sub-particle units constituting the particle is small, the change due to volume expansion and contraction of the sub-particle units during charge and discharge is small, so that the occurrence of cracks inside the particle is also significantly reduced. As the occurrence of particle breakage and internal cracks is reduced, the contact area between the lithium manganese oxide and the electrolyte becomes smaller, so that manganese dissolution due to reaction with the electrolyte at high temperatures can be suppressed, thereby improving high-temperature storage characteristics and high-temperature life characteristics, and reducing gas generation due to electrolyte side reactions. Meanwhile, the average particle diameter (D) of the first positive electrode active material 50) may be 5 μm to 20 μm. Specifically, the average particle diameter (D) of the first positive electrode active material 50 ) may be 5 ㎛ or more, 6 ㎛ or more, 7 ㎛ or more, 8 ㎛ or more, 9 ㎛ or more, 10 ㎛ or more, 11 ㎛ or more, and may be 20 ㎛ or less, 19 ㎛ or less, 18 ㎛ or less, 17 ㎛ or less, 16 ㎛ or less, 15 ㎛ or less, 14 ㎛ or less, or 13 ㎛ or less. For example, the average particle diameter (D of the first positive electrode active material 50 ) may be 5 μm to 20 μm, preferably 7 μm to 18 μm, more preferably 10 μm to 15 μm, and even more preferably 11 μm to 14 μm. When the above range of average particle diameter is satisfied, the structural stability of the first positive electrode active material is excellent, side reactions with the electrolyte are less, and the manganese elution amount at high temperatures is less. (2) Second positive electrode active material The second positive electrode active material has a layered structure and includes a lithium nickel-based oxide including nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). When the lithium nickel-based oxide is included, it can have a high energy density to realize a high capacity, and by including aluminum having a strong bonding force with oxygen atoms, the second positive electrode active material can be structurally stable, and thus cation mixing can be suppressed during charge and discharge, and the material can be electrochemically stable at high potentials, and as a result, thermal stability and capacity characteristics can be further improved compared to a ternary lithium nickel-based oxide including nickel, cobalt, and manganese. First, the lithium nickel-based oxide has a layered structure. Due to this, a cathode active material with excellent capacity characteristics and structural stability can be realized. Meanwhile, the lithium nickel-based oxide may contain nickel in an amount of 90 mol% or more among the total metals excluding lithium, preferably 91 mol% or more, more preferably 92 mol% or more, and even more preferably 93 mol% or more. When the above range is satisfied, high-capacity characteristics can be implemented by the lithium nickel-based oxide, so that the capacity problem of the lithium manganese-based oxide having a spinel structure can be solved. Specifically, the lithium nickel-based oxide may have a composition represented by the following [chemical formula 2]. [Chemical formula 2] Li a2 [Ni x2 Co y2 Mn z2 Al w2 M 2 v2 ]O2 In the above chemical formula 2, the M 2 The doping element may be at least one 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, and preferably at least one selected from the group consisting of W, Y, Ba, Ca, Ti, Mg, Ta and Nb. Also, in the chemical formula 2, 0.8≤a2≤1.2, 0.9≤x2<1, 0 <y2≤0.2, 0<z2≤0.2, 0<w2≤0.2, 0≤v2≤0.1이다. Specifically, the a2 may mean a molar ratio of lithium (Li) in the lithium nickel-based oxide, and may be 0.8≤a2≤1.2, preferably 0.9≤a2≤1.15, and more preferably 1.0≤a2≤1.1. If the a2 is less than 0.8, there is a concern that the capacity may be reduced, and if it exceeds 1.2, the particles may be sintered during the sintering process, making it difficult to manufacture the second positive electrode active material. Therefore, 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 lithium nickel-based oxide, and may be 0.9≤x2<1, preferably 0.91≤x2<1, more preferably 0.92≤x2<1, and even more preferably 0.93≤x2<1. When the above range is satisfied, a nickel content sufficient to contribute to charge and discharge in the lithium nickel-based 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 lithium nickel oxide, and 0 <y2≤0.2, 바람직하게는 0<y2≤0.18, 더 바람직하게는 0.01≤y2≤0.15, 더욱 바람직하게는 0.03≤y2≤0.12, 더욱 바람직하게는 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 lithium nickel oxide, and 0 <z2≤0.2, 바람직하게는 0<z2≤0.18, 더 바람직하게는 0.01≤z2≤0.15, 더욱 바람직하게는 0.03≤z2≤0.10일 수 있다. 상기 범위를 만족할 경우, 리튬 니켈계 산화물의 구조적 안정성을 향상시킬 수 있다. The above w2 may mean the molar ratio of Al among the total metals excluding lithium in the lithium nickel oxide, and 0 <z2≤0.2, 바람직하게는 0<z2≤0.18, 더 바람직하게는 0.01≤z2≤0.15, 더욱 바람직하게는 0.03≤z2≤0.10일 수 있다. 상기 범위를 만족할 경우, 리튬 니켈계 산화물의 구조적 안정성을 더욱 향상시킬 수 있다. The above v2 is M among all metals except lithium in lithium nickel oxide. 3 The molar ratio may be 0≤w2≤0.1, preferably 0≤w2≤0.08, and more preferably 0≤w2≤0.05. The lithium nickel-based oxide may include a second coating layer, and the second coating layer may be located on a surface of the lithium nickel-based oxide. The second coating layer can block contact between the lithium nickel-based oxide and the electrolyte to suppress the occurrence of electrolyte side reactions, improve life characteristics when applied to a battery, and increase the filling density of the positive electrode material. The second coating layer may include at least one element (hereinafter referred to as “coating element”) selected from the group consisting of Ti, W, B, F, P, Mg, Ni, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si, S, Co and Al, and preferably may include at least one element selected from the group consisting of Co and Al. The second coating layer may be included in an amount of 0.01 wt% to 5 wt% based on the total weight of the second positive electrode active material, preferably 0.03 wt% to 4 wt%, more preferably 0.04 wt% to 3 wt%, and even more preferably 0.05 wt% to 2 wt%. When the above range is satisfied, the occurrence of a side reaction between the lithium nickel-based oxide and the electrolyte is more effectively suppressed, and the life characteristics can be further improved when applied to a battery. According to one embodiment, when the second coating layer includes Co, the second coating layer may be included in an amount of 0.5 wt% to 5 wt% based on the total weight of the second positive electrode active material, preferably 1 wt% to 4 wt%, and more preferably 2 wt% to 3 wt%. According to another embodiment, when the second coating layer includes Al, the second coating layer may be included in an amount of 0.01 wt% to 0.1 wt% based on the total weight of the second positive electrode active material, preferably 0.02 wt% to 0.08 wt%, and more preferably 0.03 wt% to 0.07 wt%. The second coating layer may be formed on the entire surface of the second positive electrode active material, or may be formed partially. Specifically, when the second coating layer is formed partially on the surface of the second positive electrode active material, 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 second positive electrode active material. In addition, the lithium nickel-based oxide is a single-particle particle. When lithium nickel-based oxide in the form of single particles is included together with lithium manganese-based oxide having a spinel structure, the manganese release amount at high temperatures can be significantly reduced compared to when lithium nickel-based oxide in the form of secondary particles is included, and accordingly, a lithium secondary battery using the cathode material according to the present invention can have excellent high-temperature storage characteristics and high-temperature cycle characteristics. In addition, the initial resistance can be excellent, and the initial discharge capacity can be improved. Meanwhile, the average particle diameter (D) of the second positive electrode active material 50 ) may be 1 μm to 10 μm. Specifically, the average particle diameter (D) of the second positive electrode active material 50) may be 1 ㎛ or more, 1.5 ㎛ or more, 2 ㎛ or more, 2.5 ㎛ or more, 3 ㎛ or more, 3.5 ㎛ or more, 4 ㎛ or more, and may be 10 ㎛ or less, 9.5 ㎛ or less, 9 ㎛ or less, 8.5 ㎛ or less, 8 ㎛ or less, 7.5 ㎛ or less, 7 ㎛ or less, 6.5 ㎛ or less, 6 ㎛ or less, 5.5 ㎛ or less, 5 ㎛ or less, 4.5 ㎛ or less, 4 ㎛ or less. For example, the average particle diameter (D of the second positive electrode active material 50 ) may be 1 μm to 10 μm, preferably 2 μm to 8 μm, more preferably 2.5 μm to 6.5 μm, and even more preferably 3 μm to 5 μm. When the above range is satisfied, side reactions with the electrolyte can be minimized while preventing an increase in resistance and a decrease in output characteristics. Lithium secondary battery Next, a lithium secondary battery according to the present invention will be described. A lithium secondary battery according to the present invention comprises an electrode assembly; an electrolyte; and a battery case accommodating the electrode assembly and the electrolyte. At this time, the electrode assembly comprises a cathode including the cathode material according to the present invention described above, an anode, and a separator interposed between the cathode and the anode. Below, each component of the lithium secondary battery according to the present invention will be described in more detail. (1) Electrode assembly An electrode assembly according to the present invention includes an anode, a cathode, and a separator interposed between the anode and the cathode. FIG. 1 illustrates a pre-wound laminated structure of an electrode assembly according to one embodiment of the present invention, FIG. 2 illustrates a cross-sectional structure of an electrode (positive electrode or negative electrode) according to one embodiment of the present invention, and FIG. 3 illustrates a structure of an electrode assembly according to one embodiment of the present invention. Referring to FIGS. 1 and 2, the electrode assembly (A) of the present invention can be manufactured by winding a laminate formed by sequentially stacking a separator (12), an anode (10), a separator (12), and a cathode (11) at least once in one direction (X). At this time, the positive electrode (10) and negative electrode (11) have a structure in which an active material layer (21) is formed on a long sheet-shaped current collector (20), and may include a non-conductive portion (22) in which an active material layer (21) is not formed in some area of ​​the current collector (20). As described above, by using a positive electrode (10) and a negative electrode (11) including a non-conductive portion (22), a battery having a structure in which at least a portion of the non-conductive portion of the positive electrode (10) and negative electrode (11) defines an electrode tab can be implemented without providing a separate electrode tab. Specifically, the non-conductive portion (22) can be formed long along the winding direction (X) at one end of the current collector (20), and a current collecting plate is combined with each of the positive non-conductive portion and the negative non-conductive portion, and the current collecting plate is connected to an electrode terminal, thereby functioning as an electrode tab. For example, a battery in which the positive electrode non-coated portion and the negative electrode non-coated portion function as electrode tabs can be manufactured by the following method. First, a separator, a positive electrode, a separator, and a negative electrode are sequentially laminated so that the positive electrode non-coated portion and the negative electrode non-coated portion are positioned in opposite directions, and then wound in one direction to manufacture a jelly-roll type electrode assembly. Then, the positive and negative electrode non-coated portions are folded toward the winding center (C), and then current collector plates are welded to the positive electrode non-coated portion and the negative electrode non-coated portion respectively to join them, and the current collector plates are connected to electrode terminals to manufacture a battery. The current collector plates have a larger cross-sectional area than the strip-type electrode tabs, and since resistance is inversely proportional to the cross-sectional area of ​​a path through which current flows, when a secondary battery is formed with the above structure, the cell resistance can be significantly reduced. Meanwhile, the positive and negative electrode portions may be processed into a plurality of independently foldable segments, and at least some of the plurality of segments may be folded toward the winding center (C) of the electrode assembly. The above segments can be formed by processing the positive and negative current collectors through a metal foil cutting process such as laser notching, ultrasonic cutting, or punching. When the non-conductive portions of the positive and negative electrodes are processed in the form of multiple segments, the stress applied to the non-conductive portion during bending can be reduced, thereby preventing deformation or damage to the non-conductive portion, and improving the welding characteristics with the current collecting plate. The collector plate and the plain portion are generally joined by welding. In order to improve the welding characteristics, strong pressure should be applied to the welding area of ​​the plain portion to fold the plain portion as flat as possible. However, during this bending process, the shape of the plain portion may be distorted and deformed irregularly, and the deformed portion may come into contact with an electrode of the opposite polarity, causing an internal short circuit or inducing micro-cracks in the plain portion. However, if the plain portions of the positive and negative electrodes are processed into a plurality of independently bendable segments, the stress applied to the plain portion during bending can be relieved, thereby minimizing deformation and damage to the plain portion. In addition, when the non-conductive portion is processed in the form of segments as described above, overlap occurs between the plurality of segments during folding, which increases the welding strength with the current collector plate, and when using the latest technology such as laser welding, it is possible to prevent the problem of the laser penetrating into the electrode assembly and melting away the separator or active material. Preferably, at least some of the plurality of folded segments may overlap on the upper and lower sides of the electrode assembly, and the current collector plate may be bonded on the plurality of overlapped segments. Meanwhile, the electrode assembly according to the present invention may be formed with a structure in which an insulating layer (24) is additionally formed on the positive electrode (10), as illustrated in FIG. 3. Specifically, the insulating layer (24) may be formed to cover a portion of the positive electrode active material layer and a portion of the non-conductive portion along a direction parallel to the winding direction of the electrode assembly. In the case of a battery having a tab-less structure in which the non-conductive portion (22c) of the positive electrode (10) and the non-conductive portion (22a) of the negative electrode (11) are used as electrode tabs, an electrode assembly is formed so that the positive electrode (10) protrudes above the separator (12) and the negative electrode (11) protrudes below the separator (12), and the protruding positive electrode (10) and / or negative electrode (11) are folded and then combined with a current collecting plate. However, when the positive electrode (10) or negative electrode (11) is folded as described above, the current collector of the positive electrode (10) or negative electrode (11) is positioned close to an electrode of the opposite polarity beyond the separator, which may cause the positive electrode and negative electrode to come into electrical contact, thereby causing an internal short circuit. However, as shown in Fig. 5, when an insulating layer (24) covering the positive electrode active material layer and a portion of the non-conductive portion is formed, the positive electrode (10) and the negative electrode (11) can be prevented from electrically contacting each other by the insulating layer (24), thereby preventing a short circuit from occurring inside the battery. Preferably, the insulating layer (24) may be provided on at least one surface of the positive electrode (10) current collector, and preferably, may be provided on both surfaces of the positive electrode (10). In addition, the insulating layer (24) may be formed in an area of ​​the positive electrode (10) that is likely to face the active material layer (21a) of the negative electrode (11). For example, in the case of the non-coated portion (22c) of the positive electrode (10) that faces the negative electrode (11) after being folded, the insulating layer (24) may be formed to extend to the end of the non-coated portion (22c). However, in the case of the opposite side of the surface that faces the negative electrode (11) after being folded, it is preferable that the insulating layer (24) be formed only in a part of the non-coated portion (22c), for example, up to the point before the bending of the non-coated portion (22c). This is because, if the insulating layer (24) is formed in the entire area of ​​the non-coated portion on the opposite side of the surface that faces the negative electrode (11), electrical contact with the current collecting plate is impossible, and thus, it cannot function as an electrode tab. Meanwhile, the insulating layer (24) can be attached to the anode while securing insulating performance, and its material or component is not particularly limited. For example, the insulating layer can be an insulating coating layer or an insulating tape, and the insulating coating layer can include an organic binder and inorganic particles. At this time, the organic binder can be, for example, styrene-butadiene rubber (SBR), and the inorganic particles can be, but are not limited to, alumina oxide. Below, the anode, cathode, and separator constituting the electrode assembly are described in detail. 1) Bipolar 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 cathode slurry can be prepared by dispersing the cathode material according to the present invention in a solvent such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water. The positive electrode manufactured thus comprises the positive electrode material. Specifically, the positive electrode comprises a positive electrode current collector; and a positive electrode active material layer; and the positive electrode active material layer may comprise the positive electrode material. Meanwhile, 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 adhesive strength 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. Since the above cathode material is the same as described above, a detailed description is omitted. 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. Specific examples 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, and carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one of these may be used alone or a mixture of two or more may be used. The above-described positive electrode conductive material may be typically 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 positive electrode active material layer. The above positive electrode binder serves to improve the adhesion between positive electrode particles and the adhesive strength between the positive electrode and the positive electrode current collector, and specific examples thereof include 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 to 30 wt%, preferably 1 to 20 wt%, and more preferably 1 to 10 wt%, based on the total weight of the positive electrode active material layer. 2) Cathode The above negative electrode can be manufactured by a method of applying negative electrode slurry to one side or both sides of a long sheet-shaped negative electrode collector, removing the solvent of the negative electrode slurry through a drying process, and then rolling. Meanwhile, a negative electrode including a non-coated region can be manufactured by a method of not applying the negative electrode slurry to some areas of the negative electrode collector, for example, one end of the negative electrode collector, during the application of the negative electrode slurry. The above negative electrode slurry can be prepared by dispersing the negative electrode active material in a solvent such as distilled water, ethanol, methanol, or isopropyl alcohol. Alternatively, the cathode may be manufactured by casting the cathode slurry onto a separate support, peeling the film from the support, and laminating the resulting film onto a cathode current collector. The negative electrode manufactured thus includes a negative electrode active material. Specifically, the negative electrode includes a negative electrode current collector; and a negative electrode active material layer; and the negative electrode active material layer may include a 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. As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium can be used, and the type thereof is not particularly limited. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; (semi-)metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiO β(0 < β < 2), SnO2, vanadium oxide, lithium vanadium oxide, and other (semi-)metal oxides capable of doping and dedoping lithium; or composites containing the above (semi-)metal compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and any one or a mixture of two or more of these may be used. In addition, a metallic lithium thin film may be used as the negative active material. In addition, both low-crystallinity carbon and high-crystallinity carbon may be used as the carbon material. Soft carbon and hard carbon are representative examples of low-crystallinity carbon, and high-crystallinity carbon is representative examples of amorphous, plate-like, flaky, spherical or fibrous natural graphite or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes. The above negative active material may be included in the negative active material layer in an amount of 60 to 99 wt%, preferably 75 to 95 wt%. 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-described 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. Specific examples 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, and carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one of these may be used alone or a mixture of two or more may be used. The above-described negative electrode conductive material may be typically 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. The above negative electrode binder serves to improve the adhesion between negative electrode active material particles and the adhesive strength between the negative electrode active material and the negative electrode current collector. Specific examples thereof include 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. 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 any special restrictions. Specifically, the separator may be 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. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength. (2) Electrolyte The electrolyte according to the present invention comprises a lithium salt and an organic solvent. The lithium salt may be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt may 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. It is preferable to use the concentration of the lithium salt in the range of 0.1 to 5.0 M, preferably 0.1 to 3.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively. 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. Preferably, the lithium secondary battery according to the present invention may be a cylindrical battery having a cylindrical battery case, and may preferably be a large cylindrical battery having a form factor ratio (defined as the ratio of the diameter (Τ) to the height (H) of the cylindrical battery divided by the height) of 0.4 or more, preferably 0.4 to 0.6. Here, the form factor means a value representing the diameter and height of the cylindrical battery. The lithium secondary battery according to the present invention may be, for example, a 46110 cell (diameter 46 mm, height 110 mm, form factor ratio 0.418), a 48110 cell (diameter 48 mm, height 110 mm, form factor ratio 0.436), a 4880 cell (diameter 48 mm, height 80 mm, form factor ratio 0.600), a 4680 cell (diameter 46 mm, height 80 mm, form factor ratio 0.575). In the numerical value indicating the form factor, the first two numbers indicate the diameter of the cell, and the next two or three numbers indicate the height of the cell. FIGS. 4 and 5 disclose implementation examples of lithium secondary batteries according to the present invention. Hereinafter, a lithium secondary battery according to the present invention will be described with reference to FIGS. 4 and 5. However, FIGS. 4 and 5 only show one embodiment of the present invention, and the structure of the battery of the present invention is not limited to the range disclosed in FIGS. 4 and 5. FIG. 4 illustrates a cross-sectional view of a lithium secondary battery according to one embodiment of the present invention. Referring to FIG. 4, a lithium secondary battery (140) according to the present invention includes an electrode assembly (141), a battery case (142) in which the electrode assembly (141) and an electrolyte (not shown) are stored, and a sealing body (143) that seals an open end of the battery case (142). At this time, the electrode assembly may be a laminate of a positive electrode, a separator, and a negative electrode, which is wound in one direction. In addition, the positive electrode and the negative electrode of the electrode assembly may each include a non-coated portion on which an active material layer is not formed, and may be laminated and wound such that the positive electrode non-coated portion and the negative electrode non-coated portion are positioned at the top and bottom of the electrode assembly, respectively. Since the electrode assembly has been described above, only the remaining components excluding the electrode assembly will be described below. Meanwhile, the battery case (142) is a can-shaped container with an open end formed at the top, and is made of a conductive metal material such as aluminum or steel. The battery case accommodates an electrode assembly (141) in the inner space through the open end at the top, and also accommodates an electrolyte (not shown). Meanwhile, it is preferable that the lithium secondary battery (140) of the present invention does not include a current interruption device (CID). Meanwhile, as illustrated in FIG. 4, the battery case (142) is electrically connected to the negative electrode non-conductive portion (146b) and can function as a negative terminal that contacts an external power source and transmits current applied from the external power source to the negative electrode. If necessary, a beading portion (147) and a crimping portion (148) may be provided on the upper end of the battery case (142). The beading portion (147) may be formed by pressing the outer circumference of the battery case (142) to a distance of D1. The beading portion (147) may prevent the electrode assembly (141) accommodated inside the battery case (142) from coming out through the upper opening of the battery case (142), and may function as a support portion on which the sealing body (143) is secured. The above crimping portion (148) can be formed on the upper portion of the beading portion (147), and has an extended and bent shape to surround the outer surface of the cap plate (143a) placed on the beading portion (147) and a portion of the upper surface of the cap plate (143a). Next, the sealing member (143) is for sealing the open end of the battery case (142), and includes a cap plate (143a), a first gasket (143b) that provides airtightness and insulation between the cap plate (143a) and the battery case (142), and, if necessary, may further include a connecting plate (143c) that is electrically and mechanically coupled to the cap plate (143a). The cap plate (143a) is pressed onto a beading portion (147) formed on the battery case (142), and may be fixed by a crimping portion (148). The cap plate (143a) is a component made of a conductive metal material and covers the upper opening of the battery case (142). The cap plate (143a) is electrically connected to the positive electrode of the electrode assembly (141) and is electrically insulated from the battery case (142) through the first gasket (143b). Therefore, the cap plate (143a) can function as a positive electrode terminal of a lithium secondary battery. The cap plate (143a) can have a protrusion (143d) formed to protrude upward from its center portion C, and the protrusion (143d) can come into contact with an external power source to allow current to be applied from the external power source. A first gasket (143b) may be interposed between the cap plate (143a) and the crimping portion (148) to ensure airtightness of the battery case (142) and to provide electrical insulation between the battery case (142) and the cap plate (143a). Meanwhile, the lithium secondary battery (140) according to the present invention may further include a current collecting plate (144, 145), if necessary. The current collecting plate is coupled to the positive electrode non-conducting portion (146a) and the negative electrode non-conducting portion (146b), and is connected to the electrode terminals (i.e., the positive electrode terminal and the negative electrode terminal). Specifically, a cylindrical battery (140) according to the present invention may include a first current collecting plate (144) coupled to an upper portion of an electrode assembly (141) and a second current collecting plate (145) coupled to a lower portion of the electrode assembly (141). It may further include a first collector plate (144) and / or a second collector plate (145). The first collector plate (144) is coupled to the upper portion of the electrode assembly (141). The first collector plate (144) is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to the non-conductive portion (146a) of the positive electrode. A lead (149) may be connected to the first collector plate (144). The lead (149) may extend upward from the electrode assembly (141) and be coupled to the connection plate (143c) or may be directly coupled to the lower surface of the cap plate (143a). The coupling of the lead (149) and other components may be accomplished by welding. Preferably, the first collector plate (144) may be formed integrally with the lead (149). In this case, the lead (149) may have a plate shape that extends outward from the center of the first collector plate (144). Meanwhile, the first collector plate (144) is joined to an end of the non-conductive portion (146a) of the anode, and the joining can be accomplished by, for example, laser welding, resistance welding, ultrasonic welding, soldering, or the like. The second collector plate (145) is coupled to the lower portion of the electrode assembly (141). The second collector plate (145) is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to the non-conductive portion (146b) of the negative electrode. One side of the second collector plate (145) can be coupled to the non-conductive portion (146b) of the negative electrode, and the opposite side can be coupled to the inner bottom surface of the battery case (142). At this time, the coupling can be performed by a method such as laser welding, resistance welding, ultrasonic welding, or soldering. Meanwhile, the lithium secondary battery (140) according to the present invention may further include an insulator (146), if necessary. The insulator (146) may be arranged to cover the upper surface of the first current collecting plate (144). Since the insulator (146) covers the first current collecting plate (144), direct contact between the first current collecting plate (144) and the inner surface of the battery case (142) can be prevented. The insulator (146) is provided with a lead hole (151) through which a lead (149) extending upward from the first collector plate (144) can be drawn out. The lead (149) is drawn upward through the lead hole (151) and coupled to the lower surface of the connecting plate (143c) or the lower surface of the cap plate (143a). The insulator (146) may be made of a polymer resin material having insulating properties, such as polyethylene, polypropylene, polyimide, or polybutylene terephthalate. Meanwhile, the lithium secondary battery (140) according to the present invention may further include a venting portion (152) formed on the lower surface of the battery case (142), if necessary. The venting portion (152) corresponds to a region of the lower surface of the battery case (142) that has a thinner thickness than the surrounding region. Since the venting portion (152) is thin, it is structurally weaker than the surrounding region. Therefore, when the pressure inside the lithium secondary battery (140) increases above a certain level, the venting portion (152) ruptures, thereby allowing gas inside the battery case (152) to be discharged to the outside, thereby preventing the battery from exploding. FIG. 5 illustrates a cross-sectional view of a lithium secondary battery according to another embodiment of the present invention. Referring to FIG. 5, a lithium secondary battery (170) according to another embodiment of the present invention has a different structure of a battery case and a sealant compared to the lithium secondary battery (140) illustrated in FIG. 4, and the configuration of the electrode assembly and the electrolyte are substantially the same. Specifically, a lithium secondary battery (170) according to another embodiment of the present invention includes a battery case (171) having a rivet terminal (172) installed therethrough. The rivet terminal (172) is installed in a partially closed closed surface (upper surface in the drawing) of one end of the battery case (171). The rivet terminal (172) is riveted to a through hole (first opening of the first end) of the battery case (171) while an insulating second gasket (173) is interposed therebetween. The rivet terminal (172) is exposed to the outside in a direction opposite to the gravity direction. The rivet terminal (172) includes a terminal exposure portion (172a) and a terminal insertion portion (172b). The terminal exposure portion (172a) is exposed to the outside of the closed surface of the battery case (171). The terminal exposure portion (172a) may be located approximately at the center of the partially closed surface of the battery case (171). The maximum diameter of the terminal exposure portion (172a) may be formed larger than the maximum diameter of the through hole formed in the battery case (171). The terminal insertion portion (172b) may penetrate approximately at the center of the closed surface of the battery case (171) and be electrically connected to the non-conductive portion (146a) of the positive electrode. The terminal insertion portion (172b) may be riveted onto the inner surface of the battery case (171). That is, an end of the terminal insertion portion (172b) may have a shape that is bent toward the inner surface of the battery case (171). The maximum diameter of the end of the terminal insertion portion (172b) may be larger than the maximum diameter of the through hole of the battery case (171). The lower surface of the terminal insertion portion (172b) can be welded with the first current collecting plate (144) connected to the non-polar portion (146a) of the positive electrode. An insulating cap (174) made of an insulating material can be interposed between the first current collecting plate (144) and the inner surface of the battery case (171). The insulating cap (174) covers the upper portion of the first current collecting plate (144) and the upper edge portion of the electrode assembly (141). This prevents the outer non-polar portion (B3) of the electrode assembly (141) from coming into contact with the inner surface of the battery case (171) having a different polarity, thereby causing a short circuit. The terminal insertion portion (172b) of the rivet terminal (172) can be welded to the first current collecting plate (144) by penetrating the insulating cap (174). The second gasket (173) is interposed between the battery case (171) and the rivet terminal (172) to prevent the battery case (171) and the rivet terminal (172) having opposite polarities from electrically contacting each other. As a result, the upper surface of the battery case (171) having a substantially flat shape can function as a positive terminal of the lithium secondary battery (170). The second gasket (173) includes a gasket exposure portion (173a) and a gasket insertion portion (173b). The gasket exposure portion (173a) is interposed between the terminal exposure portion (172a) of the rivet terminal (172) and the battery case (171). The gasket insertion portion (173b) is interposed between the terminal insertion portion (172b) of the rivet terminal (172) and the battery case (171). The gasket insertion portion (173b) can be deformed together with the terminal insertion portion (172b) during riveting so as to be in close contact with the inner surface of the battery case (171). The second gasket (173) can be made of, for example, an insulating polymer resin. The gasket exposure portion (173a) of the second gasket (173) may have an extended shape so as to cover the outer surface of the terminal exposure portion (172a) of the rivet terminal (172). When the second gasket (173) covers the outer surface of the rivet terminal (172), a short circuit can be prevented from occurring during the process of connecting an electrical connection component such as a bus bar to the upper surface of the battery case (171) and / or the rivet terminal (172). Although not shown in the drawing, the gasket exposure portion (173a) may have an extended shape so as to cover not only the outer surface of the terminal exposure portion (172a) but also a part of the upper surface. In the case where the second gasket (173) is made of a polymer resin, the second gasket (173) can be joined to the battery case (171) and the rivet terminal (172) by heat fusion. In this case, the sealing at the joining interface between the second gasket (173) and the rivet terminal (172) and the joining interface between the second gasket (173) and the battery case (171) can be strengthened. Meanwhile, in the case where the gasket exposure portion (173a) of the second gasket (173) has a form that extends to the upper surface of the terminal exposure portion (172a), the rivet terminal (172) can be joined integrally with the second gasket (173) by insert injection. The remaining area (175) of the upper surface of the battery case (171), excluding the area occupied by the rivet terminal (172) and the second gasket (173), corresponds to a negative terminal having the opposite polarity to the rivet terminal (172). The second collector plate (176) is coupled to the lower portion of the electrode assembly (141). The second collector plate (176) is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the unconducted portion (146b) of the cathode. Preferably, the second collector plate (176) is electrically connected to the battery case (171). To this end, at least a portion of an edge portion of the second collector plate (176) may be interposed and fixed between the inner surface of the battery case (171) and the first gasket (178b). In one example, at least a portion of an edge portion of the second collector plate (176) may be fixed to the beading portion (180) formed at the lower end of the battery case (171) by welding while being supported by the lower surface of the beading portion (180). In a variation, at least a portion of an edge portion of the second collector plate (176) may be directly welded to the inner wall surface of the battery case (171). The second collector plate (176) may have a plurality of protrusions (not shown) formed radially on a surface facing the non-conductive portion (146b). When the protrusions are formed, the second collector plate (176) may be pressed to press the protrusions into the non-conductive portion (146b). Preferably, the ends of the second collector plate (176) and the non-conductive portion (146b) can be joined by welding, for example, laser welding. A sealing member (178) for sealing the lower open end of the battery case (171) includes a cap plate (178a) and a first gasket (178b). The first gasket (178b) electrically separates the cap plate (178a) and the battery case (171). A crimping member (181) secures the edge of the cap plate (178a) and the first gasket (178b) together. A vent member (179) is provided in the cap plate (178a). The configuration of the vent member (179) is substantially the same as in the above-described embodiment. Preferably, the cap plate (178a) is made of a conductive metal material. However, since a first gasket (178b) is interposed between the cap plate (178a) and the battery case (171), the cap plate (178a) does not have electrical polarity. The sealing body (178) seals the open end of the lower portion of the battery case (171) and discharges gas when the internal pressure of the battery cell (170) increases above a critical value. Preferably, the rivet terminal (172) electrically connected to the non-conductive portion (146a) of the positive electrode is used as the positive terminal. In addition, a portion (175) of the upper surface of the battery case (171) electrically connected to the non-conductive portion (146b) of the negative electrode through the second current collecting plate (176), excluding the rivet terminal (172), is used as the negative terminal. In this way, when the two electrode terminals are positioned on the upper portion of the lithium secondary battery, it is possible to place electrical connection components such as bus bars on only one side of the lithium secondary battery (170). This can lead to simplification of the battery pack structure and improvement of energy density. In addition, since the portion (175) used as the negative terminal has a substantially flat shape, a sufficient connection area can be secured when connecting electrical connection components such as bus bars. Accordingly, the lithium secondary battery (170) can lower the resistance at the connection portion of the electrical connection components to a desirable level. When a lithium secondary battery is formed with the above structure, the current concentration is less than that of a conventional battery having electrode tabs, so the heat generation inside the battery can be effectively reduced, and thus the thermal safety of the battery can be improved. The lithium secondary battery of the present invention as described above can be used as a unit cell in manufacturing a battery pack. FIG. 6 schematically illustrates the configuration of a battery pack according to an embodiment of the present invention. Referring to FIG. 6, a battery pack (3) according to an embodiment of the present invention includes an assembly of lithium secondary batteries (1) electrically connected thereto and a pack housing (2) accommodating the assembly. The lithium secondary battery (1) is a lithium secondary battery according to the embodiment described above. In the drawing, for the convenience of illustration, parts such as a bus bar, a cooling unit, and an external terminal for electrically connecting the lithium secondary batteries (1) are omitted. The above battery pack (3) can be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel vehicle or a two-wheel vehicle. Hereinafter, the present invention will be described in more detail through specific examples. Manufacturing example 1 MnSO 4,After mixing Al2(SO4)3 and MgO in a weight ratio of 92.98:4.65:2.37, MnSO4ㆍ7H2O containing Al2(SO4)3 and MgO was prepared using distilled water that had been purged with N2. The prepared MnSO4ㆍ7H2O was fed into a continuous stirred tank reactor (CSTR, manufacturer: EMS Tech, product name: CSTR-L0) at a rate of 10 mL / h. As an alkalizing agent, a 40% sodium hydroxide aqueous solution was fed into the sodium hydroxide aqueous solution supply portion of the reactor at a rate of 10 mL / h, and a 25% ammonia solution was fed into the ammonia solution supply portion of the reactor at a rate of 30 mL / h, while maintaining the pH at 10.5 using a pH meter and a controller. The temperature of the reactor was set to 40°C, the residence time (RT) was adjusted to 10 hours, and the mixture was stirred at a speed of 1,200 rpm to precipitate Mn3O4 containing Al. The obtained reaction solution was filtered through a filter, purified with distilled water, and dried, and then an additional process was performed to manufacture an Al-doped manganese precursor. The Al-doped manganese precursor manufactured as described above and the lithium raw material Li2CO3 were mixed in a molar ratio of 1.3:2, and then calcined at 900°C for 6 hours to produce lithium manganese oxide Li 1.3 Mn 1.9 Al 0.1 O4 was obtained. Figure 7 below is a surface image at 3,000 times magnification of the lithium manganese oxide manufactured in Manufacturing Example 1 obtained by a scanning electron microscope, and it was confirmed that the lithium manganese oxide particles manufactured above were single-particle particles. The lithium manganese oxide and boric acid (H3BO3) as a coating raw material were mixed in an amount such that the content of B was 1,000 ppm. Thereafter, a first cathode active material A having a coating layer formed was manufactured by heat-treating at 600°C for 8 hours. Manufacturing example 2 Lithium manganese oxide Li was prepared in the same manner as in Manufacturing Example 1, except that the Al-doped manganese precursor and lithium raw material Li2CO3 were calcined at 750°C for 6 hours. 1.3 Mn 1.9 Al 0.1 O4 was obtained. It was confirmed that the manufactured lithium manganese oxide had a secondary particle form. The lithium manganese oxide and boric acid (H3BO3) as a coating raw material were mixed in an amount such that the B content was 1,200 ppm. Thereafter, a first cathode active material B having a coating layer formed was manufactured by heat-treating at 600°C for 8 hours. Manufacturing example 3 A 1.0 M 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 94:5:1. Next, deionized water was added to the reactor, and nitrogen gas was purged into the reactor to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. After that, 2.0 M NaOH was added to maintain the pH inside the reactor at 10.5. Thereafter, the above transition metal aqueous solution was injected into the reactor at a rate of 10 mL / hr, and the NaOH aqueous solution and NH4OH aqueous solution were injected at a rate of 10 mL / hr and 5 mL / hr, respectively, while the co-precipitation reaction was conducted for 2 hours under the conditions of a reaction temperature of 60°C, pH 10, and a stirring speed of 1,000 rpm to obtain an average particle size (D 50 ) is 4㎛, and Ni 0.93 Co 0.05 Mn 0.01 A precursor represented by (OH)2 was prepared. The above precursor, LiOH and doping element Al were mixed so that the molar ratio of Ni:Co:Mn:Al was 93:5:1:1, and calcined at 600°C for 13 hours to obtain Li[Ni 0.93 Co 0.05 Mn 0.01 Al0.01 O2 was manufactured. Figure 8 below is a surface image at 5,000x magnification of the lithium nickel-based oxide manufactured in Manufacturing Example 3 obtained by a scanning electron microscope, and it was confirmed that the lithium nickel-based oxide particles manufactured above were single-particle particles. Then, the above Li[Ni 0.93 Co 0.05 Mn 0.01 Al 0.01 Wash O2 with water, dry, and then add Co(OH)2. Co was mixed in an amount such that the content of Co was 39,000 ppm, and Al2O3 was mixed in an amount such that the content of Al was 500 ppm. Thereafter, heat treatment was performed at 500°C for 8 hours to manufacture a second positive electrode active material A coated with Co and Al. Manufacturing example 4 A 1.0 M 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 90:6:4. Next, deionized water was added to the reactor, and nitrogen gas was purged into the reactor to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. After that, 2.0 M NaOH was added to maintain the pH inside the reactor at 11.0. Thereafter, the above transition metal aqueous solution was injected into the reactor at a rate of 10 mL / hr, and the NaOH aqueous solution and NH4OH aqueous solution were injected at a rate of 10 mL / hr and 5 mL / hr, respectively, while the co-precipitation reaction was conducted for 4 hours under the conditions of a reaction temperature of 60°C, pH 11, and a stirring speed of 500 rpm to obtain an average particle size (D 50 ) is 9㎛, and Ni 0.9 Co 0.06 Mn 0.04 A precursor represented by (OH)2 was prepared. The above precursor, LiOH and doping element Al were mixed so that the molar ratio of Ni:Co:Mn:Al was 90:6:3:1, and calcined at 800°C for 13 hours to obtain Li[Ni 0.90 Co 0.06 Mn 0.03 Al 0.01 O2 was manufactured. Figure 9 below is a surface image at 5,000x magnification of the lithium nickel-based oxide manufactured in Manufacturing Example 4 obtained by a scanning electron microscope, and it was confirmed that the lithium nickel-based oxide particles manufactured above were secondary particles. Then, the above Li[Ni 0.90 Co 0.06 Mn 0.03 Al 0.01 O2 was washed with water, dried, and then mixed with Al2O3 in an amount such that the Al content was 500 ppm. Then, heat treatment was performed at 600°C for 8 hours to manufacture an Al-coated second cathode active material B. The first positive electrode active material and the second positive electrode active material manufactured in the above manufacturing examples 1 to 4 each have the characteristics shown in Table 1 below. Composition D 50 Particle form 1st positive electrode active material ALi 1.3 Mn 1.9 Al 0.1 O412.7㎛ single particle type particle 1st positive electrode active material BLi 1.3 Mn 1.9 Al 0.1 O412.6㎛2nd particle 2nd cathode active material ALi[Ni 0.93 Co 0.05 Mn 0.01 Al 0.01 O24.0㎛ single particle type particle 2nd cathode active material BLi[Ni 0.90 Co 0.06 Mn 0.03 Al 0.01 O29㎛ secondary particles Example 1 The first positive electrode active material A manufactured in the above Manufacturing Example 1 and the second positive electrode active material A manufactured in the above Manufacturing Example 3 were mixed in a weight ratio of 60:40 to manufacture a positive electrode material, and the positive electrode material, carbon nanotubes as a conductive material, PVDF as a binder, and a hydrogenated nitrile butadiene copolymer as a dispersant were mixed in a weight ratio of 97.31:0.8:1.65:0.24 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 15 μm, dried at 130°C, and then rolled to manufacture a positive electrode. Natural graphite as a negative active material, SBR as a binder, and CMC as a dispersant were mixed in distilled water at a weight ratio of 98.1:1.0:0.9 to prepare a negative electrode slurry. The negative electrode slurry was applied to a copper current collector with a thickness of 10 μm, dried at 80°C, and then rolled to prepare a negative electrode. A polyethylene separator coated with 3㎛ CCS on both sides was interposed between the positive and negative electrodes manufactured as described above, and the separator / positive electrode / separator / negative electrode were laminated in that order and then wound to manufacture an electrode assembly. The electrode assembly manufactured as described above was inserted into a cylindrical battery can, and then an electrolyte was injected and sealed to manufacture a cylindrical lithium secondary battery. At this time, the electrolyte was prepared by adding LiPF6 to a solvent mixed with EC:DMC:EMC in a ratio of 20:75:5 at a concentration of 1.3 M. Comparative Example 1 A cylindrical lithium secondary battery was manufactured in the same manner as in Example 1, except that the second positive electrode active material B manufactured in Manufacturing Example 4 was used instead of the second positive electrode active material A. Comparative Example 2 A cylindrical lithium secondary battery was manufactured in the same manner as in Example 1, except that the first positive electrode active material B manufactured in Manufacturing Example 2 was used instead of the first positive electrode active material A. Comparative Example 3 A cylindrical lithium secondary battery was manufactured in the same manner as in Example 1, except that the first positive electrode active material B manufactured in Manufacturing Example 2 was used instead of the first positive electrode active material A, and the second positive electrode active material B manufactured in Manufacturing Example 4 was used instead of the second positive electrode active material A. Experimental Example 1: Evaluation of High Temperature Manganese Release Using the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3, the manganese release amount after activation and the manganese release amount after high-temperature storage were measured. (1) Evaluation of manganese release after activation The cylindrical lithium secondary batteries of Example 1 and Comparative Examples 1 to 3 were charged to 4.2 V and 0.1 C, respectively, at 25°C with a constant current of 0.2 C, and then activated by discharging to 2.5 V with a constant current of 0.2 C, and then fully discharged to 2.5 V. The cylindrical lithium secondary batteries were disassembled, 1 g of the negative electrode was collected, and the content of Mn eluted on the surface of the negative electrode was measured using ICP analysis. The results are shown in Table 2 below. (2) Evaluation of manganese release after high temperature storage The cylindrical lithium secondary batteries manufactured in the above Example 1 and Comparative Examples 1 to 3 were charged to 4.2 V and 0.1 C at a constant current of 0.2 C at 25°C, respectively, and discharged to 2.5 V at a constant current of 0.2 C to activate them. Thereafter, the cylindrical lithium secondary batteries were charged to 4.2 V and 0.1 C at a constant current of 0.5 C at 25°C, stored at 55°C for 2 weeks, and then reversed to 2.5 V. The cylindrical lithium secondary batteries were disassembled, 1 g of the negative electrode was collected, and the Mn content released onto the surface of the negative electrode was measured using ICP analysis. The results are shown in Table 2 below. Manganese release after activation [ppm] Manganese release after storage at 55℃ [ppm] Example 11165 Comparative Example 139165 Comparative Example 240170 Comparative Example 355201 Referring to Table 2 above, it can be confirmed that the battery manufactured in Example 1 has an absolutely smaller manganese release amount after activation and after high-temperature storage than the batteries manufactured in Comparative Examples 1 to 3. Through this, it can be understood that the battery manufactured in Example 1 has excellent high-temperature life characteristics. Experimental Example 2: Evaluation of Initial Battery Characteristics (1) Initial discharge capacity evaluation The initial discharge capacity of the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 was measured. Specifically, each cell was charged to 4.2 V, 0.1 C at a constant current of 0.25 C at 40° C, and discharged to 3.0 V at a constant current of 1 / 3 C to evaluate the initial discharge capacity. The measurement results were calculated by taking the discharge capacity of the 4680 cell manufactured in Example 1 as 100% and using this as a reference value, and the relative discharge capacities of the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 were obtained, and the results are shown in Table 3 below. (2) Initial resistance assessment The initial resistance of the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 was measured. Specifically, each cell was charged to 50% SOC at 0.5 C constant current at 40 °C, discharged for 10 seconds at 0.5 C constant current, and then the initial resistance (DCIR) was calculated from the voltage drop that occurred at that time. The measurement results were calculated by taking the initial resistance of the cylindrical lithium secondary battery manufactured in Example 1 as 100% and using this as a reference value, and the relative initial resistances of the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 were obtained, and the results are shown in Table 3 below. Initial Discharge Capacity [%] Initial Resistance [%] Example 1100.0100.0 Comparative Example 195.0101.8 Comparative Example 294.9101.8 Comparative Example 393.7102.3 Referring to Table 3 above, it can be confirmed that the battery manufactured in Example 1 has a higher initial discharge capacity and lower initial resistance than the batteries manufactured in Comparative Examples 1 to 3. Experimental Example 3: Evaluation of High Temperature Life Characteristics The life characteristics of the cylindrical lithium secondary batteries manufactured according to Example 1 and Comparative Examples 1 to 3 were measured at 40°C. Specifically, each of the cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 was charged at 40°C at a constant current of 0.25 C with a cut off of 0.1 C to 4.2 V. Then, discharge was performed at a constant current of 1 / 3 C to 3.0 V. The above charge and discharge behavior was considered as one cycle, and these cycles were repeated 400 times. The capacity retention rate after 400 cycles was measured to evaluate the high-temperature life characteristics. The measurement results are shown in Table 4 below. At this time, the capacity maintenance rate was calculated by the following formula. Capacity retention rate (%) = {(discharge capacity after 400 cycles / discharge capacity after 1 cycle)} Х 100 Capacity maintenance rate (%) Example 178.0 Comparative example 170.5 Comparative example 270.1 Comparative example 365.8 Referring to Table 4 above, it can be confirmed that the battery manufactured in Example 1 has a higher capacity retention rate when repeated charging and discharging at high temperatures than the batteries manufactured in Comparative Examples 1 to 3. Through this, it can be understood that the battery manufactured in Example 1 has excellent high-temperature life characteristics. Experimental Example 4: Evaluation of High Temperature Storage Characteristics The cylindrical lithium secondary batteries manufactured in Example 1 and Comparative Examples 1 to 3 above were charged to 4.2 V, 0.05 C under CC / CV, 0.5 C conditions at 25°C and discharged to 3.0 V under CC, 0.5 C conditions to perform initial charge / discharge, and then charged to 4.2 V, 0.05 C under CC / CV, 0.5 C conditions at 55°C and then stored at 55°C for 16 weeks. (1) Capacity maintenance rate After 16 weeks of storage, the lithium secondary battery was charged to 4.2 V, 0.05 C under CC / CV, 0.5 C conditions at 25°C and discharged to 3.0 V under CC, 0.5 C to measure the capacity during discharge. The capacity retention rate was evaluated according to the following equation, and the results are shown in Table 5 below. Capacity retention (%) = (discharge capacity after 16 weeks of storage / initial discharge capacity) Х 100 (2) Resistance increase rate After the initial charge and discharge mentioned above, the capacity was checked at room temperature, then charged to 50% of SOC based on the discharge capacity, discharged for 10 seconds with a current of 0.5 C, and the resistance was measured by the voltage drop difference at this time, which was used as the initial resistance. After 16 weeks of storage at 55 ° C, the resistance was measured using the same method, which was used as the final resistance, and the resistance increase rate was calculated using the following formula. The results are shown in Table 5 below. Resistance Increase Rate (%) = (Final Resistance - Initial Resistance) / (Initial Resistance) Х 100 Capacity retention rate (%) Resistance increase rate (%) Example 179.766.8 Comparative example 160.0128.8 Comparative example 259.8130.5 Comparative example 355.4136.4 Referring to Table 5 above, it can be confirmed that the battery manufactured in Example 1 has a higher capacity retention rate and a lower resistance increase rate when stored at high temperatures than the batteries manufactured in Comparative Examples 1 to 3. Through this, it can be understood that the battery manufactured in Example 1 has excellent high-temperature storage characteristics. (Explanation of symbols) 1: Lithium secondary battery 2: Pack Housing 3: Battery pack 10: Bipolar 11: Negative 12: Membrane 20: Whole house 21: Active material layer 21a: Negative active material layer 22: No-nonsense 22a: Cathode ignorance 22c: The ignorance of the polarity 24: Insulation layer C: Center of winding 140: Lithium secondary battery 141: Electrode assembly 142: Battery Case 143: Seal 143a: Cap plate 143b: 1st gasket 143c: Connecting plate 143d: protrusion 144: 1st Collection Plate 145: 2nd collection plate 146: Insulator 146a: Bipolar ignorance 146b: Negative polarity 147: Bidding Department 148: Crimping section 149: Lead 151: Lead Hall 152: Benting Department 170: Lithium secondary battery 171: Battery Case 172: Rivet terminal 172a: Terminal exposed part 172b: Terminal insertion part 173: 2nd gasket 173a: Gasket exposure area 173b: Gasket insert 174: Insulating cap 176: Second collector plate 178: Seal 178a: Cap plate 178b: 1st gasket 179: Vent 180: Bidding section 181: Crimping section

Claims

1. A first cathode active material comprising a lithium manganese oxide having a spinel structure; and a second cathode active material comprising a lithium nickel oxide having a layered structure and containing nickel (Ni), cobalt (Co), manganese (Mn), and aluminum (Al). The above lithium manganese oxide and the above lithium nickel oxide are single-particle type positive electrode materials.

2. In paragraph 1, The above lithium nickel-based oxide is a cathode material containing nickel at 90 mol% or more of all metals excluding lithium.

3. In paragraph 1, A cathode material, wherein the weight ratio of the first cathode active material and the second cathode active material is 75:25 to 50:

50.

4. In paragraph 1, The average particle diameter (D) of the first positive electrode active material and the second positive electrode active material 50 ) has a ratio of 5:1 to 1.5:1, anode material.

5. In paragraph 1, The average particle diameter (D) of the first positive electrode active material 50 ) is a cathode material having a diameter of 5 μm to 20 μm.

6. In paragraph 1, The average particle diameter (D) of the second positive electrode active material 50 ) is a cathode material having a thickness of 1 μm to 10 μm.

7. In paragraph 1, The above lithium manganese oxide is a cathode material having a composition represented by the following [chemical formula 1]. [Chemical Formula 1] Li 1+a1 Mr 2-x1 M 1 x1 O 4-y1 A y1 In the above chemical formula 1, Above M 1 is at least one doping element selected from the group consisting of Al, Li, Mg, Zn, B, W, Ni, Co, Fe, Cr, V, Ru, Cu, Cd, Ag, Y, Sc, Ga, In, As, Sb, Pt, Au and Si, The above A is at least one element selected from the group consisting of F, Cl, Br, I, At, and S, 0≤a1≤0.4, 0 <x1≤0.5, 0≤y1≤0.1이다.

8. In paragraph 1, The above lithium manganese oxide is M 1 A cathode material comprising 0.5 wt% to 3 wt% of lithium manganese oxide based on the total weight of the cathode material.

9. In paragraph 1, Comprising a first coating layer positioned on the surface of the lithium manganese oxide, A cathode material, wherein the first coating layer comprises at least one element selected from the group consisting of Al, Ti, W, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb. Mo, Sr, Sb, Bi, Si, S, and B.

10. In paragraph 9, A cathode material, wherein the first coating layer is included in an amount of 0.05 wt% to 0.3 wt% based on the total weight of the first cathode active material.

11. In paragraph 1, The above lithium nickel-based oxide is a cathode material having a composition represented by the following [chemical formula 2]. [Chemical formula 2] Li a2 [Ni x2 Co y2 Mr z2 Al w2 M 2 v2 ]O2 In the above chemical formula 2, M 2 is 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, 0.8≤a2≤1.2, 0.9≤x2<1, 0 <y2≤0.2, 0<z2≤0.2, 0<w2≤0.2, 0≤v2≤0.1이다.

12. In paragraph 1, A second coating layer is included on the surface of the lithium nickel-based oxide, A cathode material, wherein the second coating layer comprises at least one element selected from the group consisting of Ti, W, B, F, P, Mg, Ni, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si, S, Co and Al.

13. In paragraph 12, A cathode material, wherein the second coating layer is included in an amount of 0.01 wt% to 5 wt% based on the total weight of the second cathode active material.

14. A lithium secondary battery comprising: an electrode assembly including a cathode material according to any one of claims 1 to 13; an anode; and a separator interposed between the cathode and the anode; an electrolyte; and a battery case accommodating the electrode assembly and the electrolyte.

15. In paragraph 14, The above battery case is a cylindrical battery case, a lithium secondary battery.

16. In paragraph 14, The above lithium secondary battery is a lithium secondary battery, wherein the ratio of the diameter (T) to the height (H) (form factor ratio) is 0.4 or more.

17. In paragraph 14, A lithium secondary battery, wherein the lithium secondary battery includes a non-conductive portion on which an active material layer is not formed on at least a portion of the positive electrode and the negative electrode, and the non-conductive portion of the positive electrode and the non-conductive portion of the negative electrode are defined as electrode tabs.

Images