Preparation method for positive electrode active material, positive electrode active material, and rechargeable lithium batteries

Abstract

In one embodiment, provided are a preparation method for a positive electrode active material, a positive electrode active material, and rechargeable lithium batteries, the preparation method comprising the steps of: (1) preparing core particles containing a lithium nickel-based composite oxide; (2) mixing the core particles and cleaning water to clean the core particles; (3) removing a portion of the cleaning water so that 1 wt% to 10 wt% of the cleaning water is included with respect to 100 wt% of the total of the core particles and the cleaning water, to obtain a cleaned product; and (4) putting the cleaned product and an aluminum raw material or a boron raw material into a mixer and heat-treating same at 300 °C to 400 °C.

Description

Method for manufacturing a positive electrode active material, positive electrode active material, and lithium secondary battery

[0001] This invention relates to a method for manufacturing a positive electrode active material, a positive electrode active material, and a lithium secondary battery.

[0002] Lithium-ion batteries, which offer high energy density and portability, are primarily used as the power source for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, active research is being conducted to utilize high-energy-density lithium-ion batteries as power sources for driving or energy storage in hybrid and electric vehicles.

[0003] Various cathode active materials are being considered to realize lithium secondary batteries suitable for these applications. Among them, lithium-nickel composite oxides, lithium-nickel-manganese-cobalt composite oxides, lithium-nickel-cobalt-aluminum composite oxides, and lithium-cobalt composite oxides are primarily used as cathode active materials. With the recent surge in demand for large-capacity or high-energy-density lithium secondary batteries, there is a need to develop cathode active materials that simultaneously improve stability and performance.

[0004] A method for manufacturing a positive electrode active material containing a lithium nickel-based composite oxide improves the performance of a lithium secondary battery at high temperature and high voltage by introducing an optimal coating layer, and enhances capacity characteristics, initial charge / discharge efficiency, and high-temperature life characteristics.

[0005] In one embodiment, a method for manufacturing an anode active material is provided, comprising: (1) a step of preparing a core particle containing a lithium nickel-based composite oxide; (2) a step of mixing the core particle with a cleaning water to clean the core particle; (3) a step of removing a portion of the cleaning water to obtain a cleaned product such that the cleaning water is included in an amount of 1% to 10% by weight relative to 100% by weight of the core particle and the cleaning water; and (4) a step of introducing the cleaned product and an aluminum raw material or a boron raw material into a mixer and heat-treating at 300°C to 400°C.

[0006] In another embodiment, a positive active material is provided that is manufactured by the method for manufacturing the positive active material.

[0007] In another embodiment, a lithium secondary battery is provided comprising a positive electrode including the positive active material; a negative electrode; and an electrolyte.

[0008] According to a method for manufacturing a positive electrode active material according to one embodiment, an optimal coating layer can be introduced on the surface of the positive electrode active material efficiently and by simplifying the process, and the positive electrode active material and lithium secondary battery to which the method for manufacturing the positive electrode active material is applied can exhibit high initial charge / discharge capacity and efficiency, and can achieve long lifespan characteristics.

[0009] FIG. 1 is a schematic perspective view showing a portion of a cylindrical lithium secondary battery cut off.

[0010] Figure 2 is a cross-sectional view schematically illustrating a prismatic lithium secondary battery.

[0011] Figures 3 and 4 are schematic exploded perspective views of a pouch-type lithium secondary battery.

[0012] Specific embodiments are described below in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0013] The terms used herein are for describing exemplary embodiments only and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0014] Here, "combinations of these" refers to mixtures of components, laminates, composites, copolymers, alloys, blends, reaction products, etc.

[0015] The terms "include," "equip," or "have" used herein are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0016] In the drawings, thicknesses have been enlarged to clearly represent various layers and regions, and the same reference numerals have been used for similar parts throughout the specification. When a part such as a layer, film, region, or plate is described as being "on" or "on" another part, this includes not only cases where it is "immediately on" another part, but also cases where there is another part in between. Conversely, when a part is described as being "immediately on" another part, it means that there is no other part in between.

[0017] Here, “layer” includes not only the shape formed on the entire surface when observed in a plan view, but also the shape formed on some surfaces.

[0018] The average particle size can be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by using transmission electron microscope or scanning electron microscope images. Alternatively, the average particle size value can be obtained by measuring using dynamic light scattering, performing data analysis to count the number of particles for each particle size range, and then calculating from this. Unless otherwise defined, the average particle size is the diameter (D) of the particle at which the cumulative volume in the particle size distribution is 50 volume%. 50 It may mean ). In addition, unless otherwise defined, the average particle size is obtained by measuring the size (diameter or length of the major axis) of approximately 20 randomly selected particles from scanning electron microscope images to obtain a particle size distribution, and the diameter (D) of the particle with a cumulative volume of 50% in the said particle size distribution. 50 It may be that ) was taken as the average particle size.

[0019] Here, “or” is not interpreted in an exclusive sense; for example, “A or B” is interpreted to include A, B, A+B, etc.

[0020] Here, “metal” is interpreted as a concept including common metals, transition metals, and metalloids (semimetals).

[0021] Method for manufacturing positive electrode active material

[0022] In one embodiment, a method for manufacturing an anode active material is provided, comprising: (1) a step of preparing a core particle containing a lithium nickel-based composite oxide; (2) a step of mixing the core particle with a cleaning water to clean the core particle; (3) a step of removing a portion of the cleaning water to obtain a cleaned product such that the cleaning water is included in an amount of 1% to 10% by weight relative to 100% by weight of the core particle and the cleaning water; and (4) a step of introducing the cleaned product and an aluminum raw material or a boron raw material into a mixer and heat-treating at 300°C to 400°C.

[0023] In one embodiment, a method is proposed to improve not only high voltage high temperature lifespan characteristics but also initial charge / discharge efficiency by introducing a coating layer containing aluminum or boron onto the surface of a core particle containing a lithium nickel-based composite oxide, thereby reinforcing the particle surface and simultaneously forming a coating layer having structurally 3D lithium channels.

[0024] In addition, a first heat treatment is performed in the step of preparing core particles containing a lithium nickel-based composite oxide. However, due to the problem of high residual lithium on the surface of the core particles after the first heat treatment, a cleaning process is required, and a drying process is performed after the cleaning process. Furthermore, since a second heat treatment must be performed separately after the drying process, there is a problem of increased processing costs and reduced production volume. Accordingly, according to the method for manufacturing a positive electrode active material according to one embodiment, the drying process and the second heat treatment after the cleaning process are performed as a single process rather than as separate steps, thereby reducing processing costs. In addition, by coating aluminum or boron using a wet coating method while the mixer is operating after the cleaning process, the surface of the positive electrode active material can be coated more effectively than conventional coating methods, and by performing the drying process simultaneously with the aluminum or boron coating, processing costs can be reduced while the aluminum or boron coating can be performed uniformly.

[0025] In a method for manufacturing a positive electrode active material according to one embodiment, the step of preparing a core particle containing a lithium nickel-based composite oxide may include the step of mixing a nickel-based composite hydroxide and a lithium raw material and performing a first heat treatment. The nickel-based composite hydroxide serves as a precursor for the core particle, and the nickel-based composite hydroxide may be manufactured by a general co-precipitation method.

[0026] In the above nickel-based composite hydroxide, the nickel content based on 100 mol% of the total metal may be 60 mol% or more, for example, 60 mol% to 99 mol%, 60 mol% to 90 mol%, 60 mol% to 80 mol%, 65 mol% to 80 mol%, 70 mol% to 80 mol%, 60 mol% to 79 mol%, 60 mol% to 78 mol%, or 60 mol% to 75 mol%, 80 mol% to 99 mol%, 82 mol% to 95 mol%, 85 mol% to 95 mol%, 87 mol% to 93 mol%, 88 mol% to 92 mol%, or 90 mol% to 95 mol%, etc. When the nickel content satisfies the above range, a high capacity can be achieved.

[0027] The nickel-based composite hydroxide may further include manganese, and the manganese content based on 100 mol% of the total metal in the nickel-based composite hydroxide may be 10 mol% or more, for example, 10 mol% to 40 mol%, 15 mol% to 35 mol%, 15 mol% to 30 mol%, or 20 mol% to 30%. When the manganese content satisfies the above range, high capacity can be achieved while increasing the structural stability of the cathode active material and lowering the production cost to increase economic efficiency.

[0028] In addition, when the nickel-based composite hydroxide further contains aluminum, the aluminum content based on 100 mol% of the total metal in the nickel-based composite hydroxide may be 0.1 mol% or more, 0.5 mol% or more, or 1 mol% or more, and for example, 1 mol% to 3 mol%, 1 mol% to 2.5 mol%, or 1 mol% to 2 mol%. When the aluminum content satisfies the above range, it is possible to achieve high capacity while increasing the structural stability of the cathode active material and lowering the production cost to increase economic efficiency.

[0029] A method for manufacturing a positive electrode active material according to one embodiment may use a nickel-aluminum composite hydroxide as a precursor, in which aluminum is evenly dispersed within the structure by using an aluminum raw material during the preparation of the precursor, without additionally doping aluminum during the preparation of the core particles. When such a precursor is used, a positive electrode active material can be manufactured in which the layered structure is stably maintained even after repeated charging and discharging, and since aluminum byproducts or aluminum aggregates are not formed, the capacity, efficiency, and lifespan characteristics of the positive electrode active material can be improved.

[0030] In the above nickel-based composite hydroxide, the content of cobalt based on 100 mol% of the total metal may be 10 mol% or less, 1 mol% or less, 0.1 mol% or less, 0.01 mol% or less, 0.005 mol% or less, or 0.001 mol% or less, for example, 0 mol% to 10 mol%, 0 mol% to 1 mol%, 0 mol% to 0.1 mol%, 0 mol% to 0.01 mol%, 0 mol% to 0.005 mol%, or 0 mol% to 0.001 mol%. Such a nickel-based composite hydroxide can be economical as it avoids the increase in unit cost caused by cobalt, and can be said to maximize capacity and improve structural stability.

[0031] The above nickel-based complex hydroxide can be represented by the following chemical formula 1 as an example.

[0032] [Chemical Formula 1]

[0033] Ni x1 M 1 y1 M 2 z1 (OH)2

[0034] In Chemical Formula 1, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, and 0.9≤x1+y1+z1≤1.1, and M 1 and M 2is each independently one or more elements selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and M 1 and M 2 can be different elements.

[0035] In Chemical Formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2, or 0.9≤x1<1, 0 <y1≤0.1, 및 0≤z1≤0.1일 수 있다.

[0036] The above nickel-based complex hydroxide can be represented by the following chemical formula 2, as an example.

[0037] [Chemical Formula 2]

[0038] Ni x2 Mn y2 Al z2 M 3 w2 (OH)2

[0039] In Chemical Formula 2, 0.3≤x2≤0.9, 0.1≤y2≤0.4, 0≤z2≤0.03, 0≤w2≤0.3, and 0.9≤x2+y2+z2+w2≤1.1, and M 3 It is one or more elements selected from B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zr and Zn.

[0040] In Chemical Formula 2, for example, 0.6≤x2≤0.8, 0.1≤y2≤0.4, 0≤z2≤0.03, 0≤w2≤0.3, and 0.6≤x2≤0.8, 0.1≤y2≤0.39, 0.01≤z2≤0.03, 0≤w2≤0.29.

[0041] The above nickel-based composite hydroxide may be in the form of particles, and the average particle size (D) of the particles 50) can be 8 μm to 15 μm, for example 9 μm to 14 μm, or 10 μm to 14 μm.

[0042] The nickel-based composite hydroxide and lithium raw material can be mixed in a molar ratio of 1:0.9 to 1:1.8, for example, in a molar ratio of 1:0.9 to 1:1.5 or 1:1 to 1:1.2.

[0043] The first heat treatment above may be carried out in an oxygen atmosphere, for example, in a temperature range of 750°C to 950°C, or 780°C to 900°C, or 790°C to 890°C, and may be carried out for 2 to 20 hours, or 4 to 16 hours.

[0044] A lithium nickel-based composite oxide can be obtained through the first heat treatment above. In the lithium nickel-based composite oxide, the nickel content based on 100 mol% of the total metal excluding lithium may be 60 mol% or more, for example, 60 mol% to 99 mol%, 60 mol% to 90 mol%, 60 mol% to 80 mol%, 65 mol% to 80 mol%, 70 mol% to 80 mol%, 60 mol% to 79 mol%, 60 mol% to 78 mol%, or 60 mol% to 75 mol%, 80 mol% to 99 mol%, 82 mol% to 95 mol%, 85 mol% to 95 mol%, 87 mol% to 93 mol%, 88 mol% to 92 mol%, or 90 mol% to 95 mol%. High capacity can be achieved when the nickel content satisfies the above range. Nickel is contained in the core particles but may migrate to a portion of the coating layer during the coating process; therefore, the nickel content may refer to the nickel content contained in the entire cathode active material.

[0045] The above lithium nickel-based composite oxide may further include manganese, and the manganese content based on 100 mol% of the total metal excluding lithium may be 10 mol% or more, for example, 10 mol% to 40 mol%, 15 mol% to 35 mol%, 15 mol% to 30 mol%, or 20 mol% to 30%. When the manganese content satisfies the above range, high capacity can be achieved while increasing the structural stability of the cathode active material and lowering production costs to improve economic efficiency. Although manganese is contained in the core particles, it may migrate to some coating layers during the coating process; therefore, the manganese content may refer to the manganese content contained in the entire cathode active material.

[0046] The above lithium nickel-based composite oxide may, for example, be a lithium nickel-cobalt-aluminum-based composite oxide containing aluminum in addition to nickel and cobalt. When aluminum is contained in the above lithium nickel-based composite oxide, it is advantageous for maintaining a stable structure. In the above lithium nickel-based composite oxide, the aluminum content based on 100 mol% of the total metal excluding lithium may be 0.1 mol% or more, 0.5 mol% or more, or 1 mol% or more, and for example, 1 mol% to 3 mol%, 1 mol% to 2.5 mol%, or 1 mol% to 2 mol%. Here, the aluminum content refers to the content of aluminum present within the core particles. When the aluminum content satisfies the above range, a stable structure can be maintained, the problem of structural collapse due to charging and discharging can be suppressed, and the long lifespan characteristics of the cathode active material can be realized.

[0047] According to one embodiment, the concentration of aluminum within the core particle may be uniform. That is, it means that the aluminum concentration within the core particle does not have a gradient from the center to the surface, or that the aluminum concentration is not higher or lower outside than inside the core particle, and that the aluminum within the core particle is evenly dispersed. This can be described as a structure obtained by using aluminum raw materials during the preparation of the precursor without additionally doping aluminum during the synthesis process of the core particle. The core particle may be in the form of a secondary particle formed by the aggregation of multiple primary particles, and the aluminum content within the primary particle may be the same or similar regardless of the position of the primary particle. That is, if a primary particle is selected at an arbitrary position in the cross-section of the secondary particle and the aluminum content is measured inside rather than at the interface of the primary particle, the aluminum content can be described as the same, similar, or uniform regardless of the position of the primary particle, that is, whether the primary particle is close to the center or the surface of the secondary particle. In such a structure, a stable layered structure can be maintained even if cobalt is absent or present in minute quantities, and since no aluminum byproducts or aluminum aggregates are generated, the capacity, efficiency, and lifespan characteristics of the cathode active material can be simultaneously improved.

[0048] The above lithium nickel-based composite oxide can be represented by the following chemical formula 3 as an example.

[0049] [Chemical Formula 3]

[0050] Li a3 Ni x3 M 4 y3 M 5 z3 O 2-b3 X b3

[0051] In Chemical Formula 3, 0.9≤a3≤1.8, 0.3≤x3≤1, 0≤y3≤0.7, 0≤z3≤0.7, 0.9≤x3+y3+z3≤1.1, and 0≤b3≤0.1, and M 4 and M 5is each independently one or more elements selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and M 4 and M 5 can be different elements, and X is one or more elements selected from F, P, and S.

[0052] In Chemical Formula 3, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤z3≤0.4, or 0.8≤x3≤1, 0≤y3≤0.2, and 0≤z3≤0.2, or 0.9≤x3<1, 0 <y3≤0.1, 및 0≤z3≤0.1일 수 있다.

[0053] The above lithium nickel-based composite oxide can specifically be represented by the following chemical formula 4.

[0054] [Chemical Formula 4]

[0055] Li a4 Ni x4 Mn y4 Al z4 M 6 w4 O 2-b4 X b4

[0056] In Chemical Formula 4, 0.9≤a4≤1.8, 0.3≤x4≤0.9, 0.1≤y4≤0.4, 0≤z4≤0.03, 0≤w4≤0.3, 0.9≤x4+y4+z4+w4≤1.1, and 0≤b4≤0.1, and M 6 is one or more elements selected from B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zr and Zn, and X is one or more elements selected from F, P and S.

[0057] In Chemical Formula 4, 0.9 ≤ a4 ≤ 1.5, or 0.9 ≤ a4 ≤ 1.2. Additionally, Chemical Formula 4 may contain aluminum, in which case 0.6 ≤ x4 ≤ 0.8, 0.1 ≤ y4 ≤ 0.39, 0.01 ≤ z4 ≤ 0.03, and 0 ≤ w4 ≤ 0.29.

[0058] In Chemical Formula 4, for example, 0.6≤x4≤0.8, 0.6≤x4≤0.79, 0.6≤x4≤0.78, 0.6≤x4≤0.75, 0.65≤x4≤0.8, or 0.7≤x4≤0.79, and 0.1≤y4≤0.4, 0.1≤y4≤0.35, 0.1≤y4≤0.30, 0.1≤y4≤0.29, 0.15≤y4≤0.39, or 0.2≤y4≤0.3, and 0≤z4≤0.03, 0.01≤z4≤0.025, 0.01 <z4≤0.02, 또는 0.01<z4≤0.019일 수 있고, 0≤w4≤0.30≤w4≤0.28, 0≤w4≤0.27, 0≤w4≤0.26, 0≤w4≤0.25, 0≤w4≤0.24, 0≤w4≤0.23, 0≤w4≤0.22, 0≤w4≤0.21, 0≤w4≤0.2, 0≤w4≤0.15, 0≤w4≤0.1, 또는 0≤w4≤0.09 등일 수 있다.

[0059] The above lithium-nickel-based composite oxide may, for example, be a cobalt-free compound that does not contain cobalt or contains a very small amount, and the content of cobalt based on 100 mol% of the total metal excluding lithium may be 10 mol% or less, 1 mol% or less, 0.1 mol% or less, 0.01 mol% or less, 0.005 mol% or less, or 0.001 mol% or less, for example, 0 mol% to 10 mol%, 0 mol% to 1 mol%, 0 mol% to 0.1 mol%, 0 mol% to 0.01 mol%, 0 mol% to 0.005 mol%, or 0 mol% to 0.001 mol%. Such a nickel-based composite oxide can be said to be economical as it avoids the increase in unit cost caused by cobalt, and can maximize capacity and improve structural stability.

[0060] The core particle may be in the form of a secondary particle formed by the aggregation of a plurality of primary particles. The secondary particle may be spherical, elliptical-spherical, polyhedron, or irregular in shape, and the primary particle may be spherical, elliptical-spherical, plate-shaped, or a combination thereof. In this case, the average particle size (D) of the secondary particle 50 The depth can be 8 μm to 15 μm, for example, 9 μm to 14 μm, or 10 μm to 14 μm. By applying core particles in the form of secondary particles, the density of the final cathode active material can be increased, and the capacity, charge / discharge efficiency, rate characteristics, output characteristics, etc., can be improved.

[0061] According to one embodiment, a lithium-nickel composite oxide having a nickel content of 60 mol% or more based on 100 mol% of the total metal excluding lithium has a significantly different residual lithium content on the particle surface and different surface characteristics compared to oxides of other compositions, making it impossible to form a good coating layer in the form of a uniform film using conventional coating methods. In one embodiment, a method is proposed to very uniformly coat the particle surface of a lithium-nickel composite oxide with aluminum or boron.

[0062] In the step of cleaning the core particles by mixing the core particles with cleaning water (distilled water) according to one embodiment, the core particles and cleaning water may be mixed in a weight ratio of 0.5:1 to 1:1 to clean the core particles, for example, in a weight ratio of 0.6:1 to 1:1 or 0.7:1 to 0.9:1 to clean the core particles. Additionally, the step of cleaning the core particles by mixing the core particles and cleaning water may be performed for 1 minute to 30 minutes, for example, in a weight ratio of 1 minute to 10 minutes. In the step of preparing core particles containing a lithium nickel-based composite oxide through the cleaning process, residual lithium remaining after the first heat treatment can be removed. When conditions such as the weight ratio of the core particles and cleaning water and the cleaning time are satisfied, residual lithium on the surface of the core particles containing the lithium nickel-based composite oxide can be effectively removed, while simultaneously suppressing the problem of capacity reduction caused by the leaching of lithium inside the core particles.

[0063] In the step of obtaining a cleaned product by removing a portion of the cleaning water according to one embodiment, a portion of the cleaning water may be removed such that the cleaning water is included in an amount of 1% to 10% by weight relative to the total 100% by weight of the core particles and cleaning water, for example, a portion of the cleaning water may be removed such that the cleaning water is included in an amount of 5% to 10% by weight or 7% to 10% by weight. A product obtained by removing a portion of the cleaning water in this manner may be referred to as a cleaned product, and the cleaned product may include 90% to 99% by weight of core particles and 1% to 10% by weight of cleaning water, or 90% to 95% by weight of core particles and 5% to 10% by weight of cleaning water, or 90% to 93% by weight of core particles and 7% to 10% by weight of cleaning water. If the cleaning water is included in the cleaning product within the above range, the mixing of the cathode active materials can be performed smoothly during the subsequent drying process, and at the same time, aluminum or boron can be dissolved in the remaining cleaning water, allowing for a uniform aluminum or boron coating.

[0064] In a method for manufacturing a positive electrode active material according to one embodiment, a cleaning product containing 1% to 10% by weight of cleaning water relative to 100% by weight of the core particles and the cleaning water, and an aluminum raw material are introduced into a mixer. In this process, drying of the cleaning product and coating of the positive electrode active material can be performed simultaneously, thereby simplifying the process, reducing processing costs, and increasing production volume. Additionally, by mixing the cleaning product containing 1% to 10% by weight of cleaning water with the aluminum raw material, the aluminum raw material or boron raw material may be partially dissolved in the remaining cleaning water, and accordingly, aluminum or boron can be uniformly coated in a thin thickness on the surface of the positive electrode active material. Accordingly, the manufactured positive electrode active material can achieve excellent capacity and lifespan characteristics. The mixer is suitable for drying the cleaning product containing 1% to 10% by weight of cleaning water and is suitable for mixing the cleaning product with the aluminum raw material or boron raw material, and is also suitable for performing appropriate heat treatment to ensure that aluminum or boron is uniformly coated on the surface of the positive electrode active material.

[0065] The above aluminum raw material may be introduced into a mixer in a form dissolved in an aqueous solvent. The above aqueous solvent may include distilled water, an alcohol-based solvent, or a combination thereof. The above aluminum raw material may be aluminum sulfate, aluminum sulfate hydrate, aluminum nitrate, aluminum nitrate hydrate, or a combination thereof, and may be, for example, aluminum nitrate hydrate. Aluminum nitrate hydrate can be considered the optimal raw material for forming a uniform aluminum coating layer on the surface of the core particles. The above boron raw material may be boron acid (H3BO3), boron sulfate, boron nitride, or a combination thereof, and may be, for example, boron acid. Boronic acid can be considered the optimal raw material for forming a uniform boron coating layer on a lithium nickel-based composite oxide.

[0066] Based on the total metal excluding lithium in the core particles and the total aluminum of the aluminum raw material at 100 mol%, the aluminum content in the aluminum raw material may be 0.1 mol% to 1.0 mol%, for example, 0.1 mol% to 0.5 mol%, 0.2 mol% to 0.5 mol%, or 0.2 mol% to 0.3 mol%. By adding aluminum within the above range, a coating layer having a uniform thickness with a thin thickness of several nanometers to several hundred nanometers can be formed, and the amount of gas generated in the lithium secondary battery under high voltage or high temperature operating conditions can be reduced, and high capacity and long life characteristics can be improved.

[0067] Based on the total metal excluding lithium in the core particles and the total boron of the boron raw material being 100 mol%, the boron content in the boron raw material may be 0.1 mol% to 3.0 mol%, for example, 0.1 mol% to 2.0 mol%, 0.1 mol% to 1.0 mol%, 0.2 mol% to 1.0 mol%, 0.2 mol% to 0.6 mol%, 0.4 mol% to 1.0 mol%, 0.4 mol% to 0.8 mol%, 0.8 mol% to 1.2 mol%, 0.6 mol% to 0.8 mol%, or 0.4 mol% to 0.6 mol%. By adding boron content within the above range, a coating layer having a uniform thickness with a thin thickness of several nanometers to several hundred nanometers can be formed, and the amount of gas generated by the lithium secondary battery under high voltage or high temperature operating conditions can be reduced, and high capacity and long life characteristics can be improved.

[0068] In a method for manufacturing a positive electrode active material according to one embodiment, a coating layer can be formed on the surface of a core particle by introducing the cleaning product and the aluminum raw material into a mixer and heat-treating at 300°C to 400°C.

[0069] Unlike the wet pre-addition method, in which the salt, which is the coating raw material, is completely dissolved first and then the core particles are added; the wet post-addition method, in which the core particles are added and then the salt, which is the coating raw material, is added; and the dry method, in which the core particles in powder form and the coating raw material in powder form are mixed and heat-treated, one embodiment can be said to apply optimal conditions for forming a uniform aluminum coating layer on core particles containing a lithium nickel-based composite oxide by lowering the residual lithium content on the surface by cleaning the core particles and then proceeding with aluminum coating.

[0070] In a method for manufacturing a positive electrode active material according to one embodiment, the cleaning product and the aluminum raw material may be introduced into a mixer that mixes at a speed of 50 RPM or less, for example, the cleaning product and the aluminum raw material may be introduced into a mixer that mixes at a speed of 20 RPM or less. A mixer that mixes at a speed of 50 RPM or less may be, for example, a Rödige mixer. When the speed of the mixer falls within the above range, it is possible to prevent the cleaning product inside the mixer from not mixing smoothly due to moisture, and to simultaneously proceed with coating while smoothly drying the cleaning product.

[0071] At this time, the cleaning product introduced into the mixer may contain 1% to 10% by weight of cleaning water relative to 100% by weight of the core particles and cleaning water, for example, 5% to 10% by weight of cleaning water, or 7% to 10% by weight of cleaning water. When the cleaning water is included in the cleaning product within the above range, the mixing of the cathode active materials is performed smoothly during the subsequent drying process, and at the same time, aluminum is dissolved in the remaining cleaning water, allowing for a uniform aluminum coating.

[0072] A method for manufacturing a positive electrode active material according to one embodiment may include the step of introducing the cleaned product and the aluminum raw material into a mixer that mixes at a speed of 50 RPM or less, and heat treating at 300°C to 400°C, for example, and may include the step of heat treating at 350°C to 390°C. Generally, a drying process is performed at about 200°C after the cleaning process, and a secondary heat treatment is performed at about 800°C after the drying process. According to the method for manufacturing a positive electrode active material according to one embodiment, these drying process and secondary heat treatment are not performed as separate processes but are performed as a single process at a low temperature, thereby reducing processing costs and allowing for uniform aluminum coating.

[0073] positive electrode active material

[0074] In one embodiment, a positive electrode active material is provided according to the method for manufacturing the positive electrode active material. By introducing a coating layer containing a specific amount of aluminum onto the surface of a core particle containing a lithium nickel-based composite oxide, a method is proposed that can maintain a stable structure even at high voltage, realize high capacity and long lifespan characteristics, and improve high-temperature storage characteristics.

[0075] core particles

[0076] The core particle contains a lithium nickel-based composite oxide, and the lithium nickel-based composite oxide can be represented by Chemical Formula 2. As the core particle has been described above, a detailed explanation is omitted.

[0077] The above-mentioned core particles are susceptible to chemical attack from components within the electrolyte when operating the battery under high voltage or high temperature conditions, which can lead to many side reactions with the electrolyte and consequently cause a large amount of gas generation, resulting in reduced battery life and safety. However, these problems can be resolved by introducing a coating layer according to an embodiment to be described later.

[0078] coating layer

[0079] A positive electrode active material according to one embodiment includes a coating layer containing aluminum located on the surface of a core particle.

[0080] The aluminum content based on 100 mol% of the total metal excluding lithium on the surface of the positive active material, as measured by SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) on the surface of the positive active material, may be 0.1 mol% to 1.0 mol%, for example, 0.1 mol% to 0.5 mol%, 0.2 mol% to 0.5 mol%, or 0.2 mol% to 0.3 mol%. When the aluminum content according to SEM-EDS analysis satisfies the above range, the positive active material can achieve excellent capacity and lifespan characteristics by containing a thin layer of aluminum at a high concentration on its surface.

[0081] SEM-EDS can be performed using Helios G4 HX under conditions of HT: 3kV, current: 0.8nA, live time: 90s.

[0082] The boron content based on 100 mol% of the total metal excluding lithium on the surface of the positive active material, as measured by SEM-EDS on the surface of the positive active material, may be 0.1 mol% to 3.0 mol%, for example, 0.1 mol% to 2.0 mol%, 0.1 mol% to 1.0 mol%, 0.2 mol% to 1.0 mol%, 0.2 mol% to 0.6 mol%, 0.4 mol% to 1.0 mol%, 0.4 mol% to 0.8 mol%, 0.8 mol% to 1.2 mol%, 0.6 mol% to 0.8 mol%, or 0.4 mol% to 0.6 mol%. When the boron content according to SEM-EDS analysis satisfies the above range, the positive active material can achieve excellent capacity and lifespan characteristics by containing boron at a high concentration and with a thin thickness on its surface.

[0083] According to one embodiment, the coating layer may be in the form of a film that continuously covers the surface of the core particle, or, for example, in the form of a shell that covers the entire surface of the core particle. This is distinguished from a structure in which the coating is partially applied to only a part of the surface of the core particle. According to one embodiment, the coating layer can be formed to completely cover the surface of the core particle while having a very thin and uniform thickness. Accordingly, the resistance of the cathode active material does not increase or the capacity does not decrease, structural stability is improved, side reactions with the electrolyte can be effectively suppressed, gas generation under high voltage and high temperature conditions is reduced, and long life characteristics can be achieved.

[0084] According to one embodiment, the thickness of the coating layer may be 5 nm to 200 nm, for example, 5 nm to 150 nm, 5 nm to 100 nm, 5 nm to 80 nm, 5 nm to 50 nm, or 10 nm to 50 nm. When the coating layer satisfies the above thickness range, the structural stability of the positive electrode active material can be improved and side reactions with the electrolyte can be effectively suppressed without increasing resistance or decreasing capacity due to the coating. The thickness of the coating layer can be measured, for example, through SEM, TEM, TOF-SIMS, XPS, or EDS analysis, and for example, through EDS line profile analysis of the cross-section of the positive electrode active material.

[0085] Meanwhile, the coating layer may further contain nickel, cobalt, or a combination thereof in addition to aluminum. Nickel and / or cobalt may be those contained in the core particles that are introduced during the coating layer formation process, and their content is not particularly limited. A coating layer according to one embodiment essentially contains aluminum while optionally containing nickel and / or cobalt, and is formed with a thin and uniform thickness, which can improve the high voltage characteristics of the cathode active material and enhance the lifespan characteristics.

[0086] The obtained positive electrode active material may be said to comprise a core particle containing a lithium nickel-based composite oxide, and a coating layer located on the surface of the core particle containing aluminum oxide, lithium-aluminum oxide, or a combination thereof.

[0087] anode

[0088] In one embodiment, a positive electrode is provided that includes a current collector and a positive active material layer located on the current collector, wherein the positive active material layer comprises the aforementioned positive active material. The positive active material layer may further include other types of positive active materials in addition to the aforementioned positive active material. Additionally, the positive active material layer may optionally further include a binder, a conductive material, or a combination thereof.

[0089] bookbinder

[0090] The binder serves to adhere the positive active material particles well to each other and also to adhere the positive active material well to the current collector. Representative examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0091] Challenge

[0092] A conductive material is used to impart conductivity to an electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Examples of conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0093] The content of the binder and the conductive material may be 0.5% to 5% by weight each with respect to 100% by weight of the positive active material layer.

[0094] Al thin films can be used as the positive current collector, but are not limited thereto.

[0095] lithium secondary battery

[0096] In one embodiment, a lithium secondary battery comprising the aforementioned positive electrode, negative electrode, and electrolyte is provided. As an example, the lithium secondary battery may include a positive electrode, a negative electrode, a separator located between the positive electrode and the negative electrode, and an electrolyte.

[0097] Lithium secondary batteries can be classified into cylindrical, prismatic, pouch, coin, etc., depending on their shape. FIGS. 1 to 4 are schematic diagrams illustrating a lithium secondary battery according to one embodiment, where FIG. 1 is a cylindrical battery, FIG. 2 is a prismatic battery, and FIGS. 3 and 4 are pouch-type batteries. Referring to FIGS. 1 to 4, the lithium secondary battery (100) may include an electrode assembly (40) having a separator (30) interposed between a positive electrode (10) and a negative electrode (20), and a case (50) in which the electrode assembly (40) is housed. The positive electrode (10), the negative electrode (20), and the separator (30) may be impregnated with an electrolyte (not shown). The lithium secondary battery (100) may include a sealing member (60) that seals the case (50) as in FIG. 1. In addition, in FIG. 2, the lithium secondary battery (100) may include a positive lead tab (11) and a positive terminal (12), a negative lead tab (21) and a negative terminal (22). As shown in FIG. 3 and FIG. 4, the lithium secondary battery (100) may include an electrode tab (70), namely a positive tab (71) and a negative tab (72), which serve as an electrical path to guide the current formed in the electrode assembly (40) to the outside.

[0098] cathode

[0099] The cathode may include a current collector and a cathode active material layer located on the current collector, and the cathode active material layer may include a cathode active material and may further include a binder, a conductive material, or a combination thereof.

[0100] cathode active material

[0101] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0102] A material capable of reversibly intercalating / deintercalating the above lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0103] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn may be used.

[0104] As a material capable of doping and undoping the above lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The above Si-based negative electrode active material may include silicon, silicon-carbon composites, and SiOx(0 <x≤2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소(Si를 제외함), 15족 원소, 16족 원소, 전이금속, 희토류 원소 및 이들의 조합에서 선택되는 원소이며, 예컨대 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 및 이들의 조합에서 선택됨), 또는 이들의 조합일 수 있다. 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn 합금 또는 이들의 조합일 수 있다.

[0105] The above silicon-carbon composite may be a composite of silicon and amorphous carbon. The average particle size (D) of the silicon-carbon composite particles50 The thickness may be, for example, 0.5 μm to 20 μm. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, it may include a secondary particle (core) assembled from silicon primary particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particle. The amorphous carbon may also be located between the silicon primary particles, so that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0106] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. Examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, etc.

[0107] When the silicon-carbon composite comprises silicon and amorphous carbon, the silicon content may be 10% to 50% by weight with respect to 100% by weight of the silicon-carbon composite, and the amorphous carbon content may be 50% to 90% by weight. Additionally, when the composite comprises silicon, amorphous carbon, and crystalline carbon, the silicon content may be 10% to 50% by weight with respect to 100% by weight of the silicon-carbon composite, the crystalline carbon content may be 10% to 70% by weight, and the amorphous carbon content may be 20% to 40% by weight.

[0108] In addition, the thickness of the amorphous carbon coating layer may be 5 nm to 100 nm. The average particle size (D) of the silicon particles (primary particles) 50) can be 10 nm to 1 µm, or 10 nm to 200 nm. The silicon particles may exist as silicon alone, in the form of a silicon alloy, or in an oxidized form. The oxidized form of silicon is SiO x (0 <x≤2)로 표시될 수 있다. 이때, 산화 정도를 나타내는 Si:O의 원자 함량 비율은 99:1 내지 33:67일 수 있다. 본 명세서에서, 별도의 정의가 없는 한, 평균 입경(D 50 ) refers to the diameter of the particle with a cumulative volume of 50 volume% in the particle size distribution.

[0109] The above Si-based negative electrode active material or Sn-based negative electrode active material may be used in combination with a carbon-based negative electrode active material. When the Si-based negative electrode active material or Sn-based negative electrode active material and the carbon-based negative electrode active material are mixed and used, the mixing ratio may be 1:99 to 90:10 by weight.

[0110] bookbinder

[0111] The above binder serves to effectively bond the negative electrode active material particles to each other and also to effectively bond the negative electrode active material to the current collector. As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used.

[0112] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide imide, polyimide, or combinations thereof.

[0113] The water-based binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylenepropylenediene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0114] When a water-based binder is used as the cathode binder, a cellulose-based compound capable of imparting viscosity may be further included. As this cellulose-based compound, one or more types such as carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or alkali metal salts thereof may be mixed and used. Na, K, or Li may be used as the alkali metal.

[0115] The dry binder is a polymer material capable of fiberization, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0116] Challenge

[0117] A conductive material is used to impart conductivity to an electrode, and any electronically conductive material that does not cause chemical changes can be used in the battery being constructed. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, ketjenblack, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials in the form of metal powder or metal fibers including copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0118] The content of the negative electrode active material may be 95% to 99.5% by weight with respect to 100% by weight of the negative electrode active material layer, and the content of the binder may be 0.5% to 5% by weight with respect to 100% by weight of the negative electrode active material layer. For example, the negative electrode active material layer may contain 90% to 99% by weight of the negative electrode active material, 0.5% to 5% by weight of the binder, and 0.5% to 5% by weight of the conductive material.

[0119] The whole house

[0120] The negative current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or alloys thereof, and may be in the form of a foil, sheet, or foam. The thickness of the negative current collector may be, for example, 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0121] electrolytes

[0122] The electrolyte for a lithium secondary battery may be, for example, an electrolyte solution, which may include a non-aqueous organic solvent and a lithium salt.

[0123] Non-aqueous organic solvents serve as a medium through which ions involved in the electrochemical reaction of a cell can move. Non-aqueous organic solvents may be carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvents, aprotic solvents, or a combination thereof.

[0124] Carbonate-based solvents that may be used include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), etc. Ester-based solvents that may be used include methyl acetate, ethyl acetate, n-propyl acetate, t-butyl acetate, methylpropionate, ethylpropionate, decanolide, mevalonolactone, valerolactone, caprolactone, etc. As ether-based solvents, dibutyl ether, tetraglame, diglame, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, tetrahydrofuran, etc. may be used. Additionally, as ketone-based solvents, cyclohexanone, etc. may be used. As alcohol-based solvents, ethyl alcohol, isopropyl alcohol, etc. may be used, and as aprotic solvents, nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, an aromatic ring, or an ether group); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane, 1,4-dioxolane; sulfolanes, etc. may be used.

[0125] Non-aqueous organic solvents can be used alone or in a mixture of two or more types, and when two or more types are mixed, the mixing ratio can be appropriately adjusted according to the desired battery performance, which is widely understood by those working in the field.

[0126] When using a carbonate-based solvent, a mixture of cyclic carbonates and chain carbonates can be used, and the cyclic carbonates and chain carbonates can be mixed in a volume ratio of 1:1 to 1:9.

[0127] The non-aqueous organic solvent may further include an aromatic hydrocarbon-based organic solvent. For example, a carbonate-based solvent and an aromatic hydrocarbon-based organic solvent may be mixed and used in a volume ratio of 1:1 to 30:1.

[0128] The electrolyte may further include vinyl ethyl carbonate, vinylene carbonate, or ethylene carbonate-based compounds to improve battery life.

[0129] Representative examples of the above ethylene carbonate compounds include fluoroethylene carbonate, difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, and cyanoethylene carbonate.

[0130] Lithium salts are substances that dissolve in organic solvents and act as a source of lithium ions within the battery, enabling the basic operation of rechargeable lithium batteries and facilitating the movement of lithium ions between the anode and cathode. Representative examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO2C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide; LiFSI), LiC4F9SO3, and LiN(C x F 2x+1 SO2)(C y F 2y+1 It may include one or more selected from SO2)(x and y are integers from 1 to 20), lithium trifluoromethane sulfonate, lithium tetrafluoroethane sulfonate, lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0131] It is preferable to use a lithium salt concentration within the range of 0.1M to 2.0M. When the lithium salt concentration falls within the above range, the electrolyte has appropriate ionic conductivity and viscosity, so it can exhibit excellent performance and lithium ions can move effectively.

[0132] separator

[0133] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. As such a separator, polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers thereof may be used, and of course, mixed multilayer films such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polyethylene three-layer separators, and polypropylene / polyethylene / polypropylene three-layer separators may be used.

[0134] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0135] The porous substrate may be a polymer membrane formed from any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more of these. The porous substrate may include glass fibers or be a composite membrane of a polymer and glass fibers.

[0136] The porous substrate may have a thickness of about 1 μm to 40 μm, and may have a thickness of, for example, 1 μm to 30 μm, 1 μm to 20 μm, 5 μm to 15 μm, or 10 μm to 15 μm.

[0137] The above organic material may include a (meth)acrylic copolymer comprising a first structural unit derived from (meth)acrylamide, and a second structural unit comprising at least one of a structural unit derived from (meth)acrylic acid or (meth)acrylate and a structural unit derived from (meth)acrylamideidosulfonic acid or its salt.

[0138] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, It may include inorganic particles selected from SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto. The average particle size (D) of the inorganic particles 50 ) can be 1 nm to 2000 nm, for example, 100 nm to 1000 nm, or 100 nm to 700 nm.

[0139] The above organic and inorganic materials may exist mixed in a single coating layer, or may exist in a stacked form with a coating layer containing organic materials and a coating layer containing inorganic materials.

[0140] The thickness of the coating layer may be 0.5 μm to 20 μm, for example, 1 μm to 10 μm, or 1 μm to 5 μm.

[0141] Examples and comparative examples of the present invention are described below. The following examples are merely illustrative of the present invention, and the present invention is not limited to the following examples.

[0142] Example 1

[0143] 1. Preparation of positive electrode active material

[0144] Average particle size (D 50 Ni with a ) of approximately 14 µm 0.91 Co 0.08 Al 0.01 (OH)2 and LiOH were mixed in a 1:1 molar ratio and subjected to a first heat treatment at 800°C for 15 hours in an oxygen atmosphere to obtain a composition of LiNi 0.91 Co 0.08 Al 0.01 O2 and average particle size (D 50 A core particle containing a lithium nickel-based composite oxide in the form of a secondary particle with a thickness of approximately 14 μm was prepared.

[0145] Two tons of distilled water (washing water) and two tons of manufactured core particles were added to a 10,000 L mixer (Rödige), and the mixture was stirred for about 5 minutes to prepare a first mixed solution. Subsequently, the washing water was removed from the first mixed solution using a filter press until the residual distilled water was 10% by weight relative to the total 100% by weight of the core particles and washing water, thereby obtaining a washed product.

[0146] Distilled water and aluminum nitrate hydrate (Al(NO3)3-9H2O) were added to a 20L reactor and stirred for about 30 minutes to prepare a second mixed solution. At this time, distilled water was added in an amount of 5 wt% relative to 100 wt% of the total cathode active material finally prepared, and the aluminum content in the aluminum nitrate hydrate was added in an amount of 0.1 mol% relative to 100 mol% of the total metals excluding lithium in the cathode active material finally prepared.

[0147] The above-mentioned cleaning product and the second mixing solution were introduced into the above-mentioned mixer (Rödige), and while mixing at a speed of 5 RPM, the mixer was heated to 380°C at a heating rate of 2.5°C / min, and heat treatment (drying and coating) was performed simultaneously for a total of 5 hours to obtain the positive electrode active material.

[0148] 2. Manufacture of coin-type half-batteries

[0149] A cathode active material layer slurry was prepared by mixing 98.5 wt% of the manufactured cathode active material, 1.0 wt% of a polyvinylidene fluoride binder, and 0.5 wt% of a carbon nanotube conductive material, and the slurry was coated onto an aluminum foil current collector, dried, and rolled to produce a cathode.

[0150] A coin-type half-cell was manufactured using the above-mentioned positive electrode, lithium metal counter electrode, and electrolyte by a conventional method. Polytetrafluoroethylene separator was used as the electrolyte, and an electrolyte solution was used in which 1M LiPF6 was dissolved in a solvent mixed with ethylene carbonate and dimethyl carbonate in a volume ratio of 3:7.

[0151] Example 2

[0152] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 1, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate was 0.2 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0153] Example 3

[0154] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 1, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate was 0.3 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0155] Example 4

[0156] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 1, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate was 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0157] Example 5

[0158] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 1, except that in the manufacture of the positive electrode active material, aluminum sulfate was used instead of aluminum nitrate, and the amount of aluminum in the aluminum sulfate was 0.1 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0159] Example 6

[0160] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 5, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum sulfate was 0.2 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0161] Example 7

[0162] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 5, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum sulfate was 0.3 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0163] Example 8

[0164] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 5, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum sulfate was 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0165] Example 9

[0166] Average particle size (D 50 Ni with a ) of approximately 14 µm 0.75 Mn 0.23 Al 0.02 (OH)2 and LiOH are mixed in a 1:1 molar ratio and subjected to a first heat treatment at 800°C for 15 hours in an oxygen atmosphere to obtain a composition of LiNi 0.75Mn 0.23 Al 0.02 O2 and average particle size (D 50 A core particle containing a lithium nickel-based composite oxide in the form of a secondary particle with a thickness of approximately 14 μm was prepared.

[0167] Two tons of distilled water (washing water) and two tons of manufactured core particles were added to a 10,000 L mixer (Rödige), and the mixture was stirred for about 5 minutes to prepare a first mixed solution. Subsequently, the washing water was removed from the first mixed solution using a filter press until the residual distilled water was 10% by weight relative to the total 100% by weight of the core particles and washing water, thereby obtaining a washed product.

[0168] Distilled water and aluminum nitrate hydrate (Al(NO3)3-9H2O) were added to a 20L reactor and stirred for about 30 minutes to prepare a second mixed solution. At this time, distilled water was added in an amount of 5 wt% relative to 100 wt% of the total cathode active material finally prepared, and the aluminum content in the aluminum nitrate hydrate was added in an amount of 0.1 mol% relative to 100 mol% of the total metals excluding lithium in the cathode active material finally prepared.

[0169] The above-mentioned cleaning product and the second mixing solution were introduced into the above-mentioned mixer (Rödige), and while mixing at a speed of 5 RPM, the mixer was heated to 380°C at a heating rate of 2.5°C / min, and heat treatment (drying and coating) was performed simultaneously for a total of 5 hours to obtain the positive electrode active material.

[0170] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0171] Example 10

[0172] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 9, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate hydrate was 0.2 mol% relative to 100 mol% of the total metal excluding lithium in the finally manufactured positive electrode active material.

[0173] Example 11

[0174] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 9, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate hydrate was 0.3 mol% relative to 100 mol% of the total metal excluding lithium in the finally manufactured positive electrode active material.

[0175] Example 12

[0176] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 9, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate hydrate was 0.4 mol% relative to 100 mol% of the total metal excluding lithium in the finally manufactured positive electrode active material.

[0177] Example 13

[0178] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as in Example 9, except that in the manufacture of the positive electrode active material, the amount of aluminum in the aluminum nitrate hydrate was 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the finally manufactured positive electrode active material.

[0179] Example 14

[0180] Distilled water and boronic acid (H3BO3) were added to a 20L reactor and stirred for about 30 minutes to prepare a second mixed solution. At this time, distilled water was added in an amount of 5 wt% relative to 100 wt% of the total cathode active material finally prepared, and the boron content in the boronic acid was added in an amount of 0.25 mol% relative to 100 mol% of the total metals excluding lithium in the cathode active material finally prepared.

[0181] The same cleaning product prepared in Example 1 and the second mixing solution were introduced into a mixer (Rödige), and while mixing at a speed of 5 RPM, the mixer was heated to 380°C at a heating rate of 2.5°C / min, and heat treatment (drying and coating) was performed simultaneously for a total of 5 hours to obtain an anode active material.

[0182] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0183] Example 15

[0184] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as in Example 14, except that in the preparation of the positive electrode active material, the boron content in the boron acid was added in an amount of 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0185] Example 16

[0186] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as in Example 14, except that in the preparation of the positive electrode active material, the boron content in the boron acid was added in an amount of 1.0 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0187] Comparative Example 1

[0188] A cleaning product identical to that prepared in Example 1 was introduced into a mixer, and while mixing at a speed of 5 RPM, the temperature of the mixer was raised to 380°C and dried for a total of 5 hours to produce a dried product.

[0189] The above dried product and aluminum oxide (Al2O3) were mixed, and a second heat treatment was performed at 400°C for 8 hours in an oxygen atmosphere to produce a positive electrode active material. At this time, the aluminum content in the aluminum oxide was added in an amount of 0.1 mol% relative to 100 mol% of the total metal excluding lithium in the finally produced positive electrode active material.

[0190] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0191] Comparative Example 2

[0192] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as Comparative Example 1, except that the aluminum content in the aluminum oxide was added in an amount of 0.2 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0193] Comparative Example 3

[0194] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as Comparative Example 1, except that the aluminum content in the aluminum oxide was added in an amount of 0.3 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0195] Comparative Example 4

[0196] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as Comparative Example 1, except that the aluminum content in the aluminum oxide was added in an amount of 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0197] Comparative Example 5

[0198] 600g of distilled water and aluminum nitrate hydrate were added to a 1L reactor, and a coating solution was prepared by stirring at approximately 350 rpm for about 5 minutes for salt dissolution. It was confirmed that the salt was completely dissolved in the coating solution and that it was colorless and transparent. 500g of the same dried product prepared in Comparative Example 1 was added to the coating solution being continuously stirred for 1.5 minutes, and stirred for about 30 minutes. At this time, the aluminum content in the aluminum nitrate hydrate was designed to be 0.2 mol% relative to 100 wt% of the total metal excluding lithium in the finally prepared cathode active material.

[0199] The solvent was removed from the mixed solution using an aspirator and a filter press, and the product was vacuum dried at 190°C to obtain a coated product.

[0200] The above-mentioned coating product was subjected to a second heat treatment at 750°C for 8 hours in an oxygen atmosphere to produce an anode active material.

[0201] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0202] Comparative Example 6

[0203] In the preparation of the positive active material, the positive active material and the coin-type half-cell were prepared in substantially the same manner as in Example 1, except that the mixer was heated to 450°C instead of 380°C to perform drying and coating simultaneously.

[0204] Comparative Example 7

[0205] A cleaning product identical to that prepared in Example 9 was introduced into a mixer, and while mixing at a speed of 5 RPM, the temperature of the mixer was raised to 380°C and dried for a total of 5 hours to produce a dried product.

[0206] The above dried product and aluminum oxide (Al2O3) were mixed, and a second heat treatment was performed at 400°C for 8 hours in an oxygen atmosphere to produce a positive electrode active material. At this time, the aluminum content in the aluminum oxide was added in an amount of 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the finally produced positive electrode active material.

[0207] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0208] Comparative Example 8

[0209] 600g of distilled water and aluminum nitrate hydrate were added to a 1L reactor, and a coating solution was prepared by stirring at approximately 350 rpm for about 5 minutes for salt dissolution. It was confirmed that the salt was completely dissolved in the coating solution and that it was colorless and transparent. 500g of the same dried product prepared in Comparative Example 7 was added to the coating solution being continuously stirred for 1.5 minutes, and stirred for about 30 minutes. At this time, the aluminum content in the aluminum nitrate hydrate was designed to be 0.2 mol% relative to 100 wt% of the total metal excluding lithium in the finally prepared cathode active material.

[0210] The solvent was removed from the mixed solution using an aspirator and a filter press, and the product was vacuum dried at 190°C to obtain a coated product.

[0211] The above-mentioned coating product was subjected to a second heat treatment at 750°C for 8 hours in an oxygen atmosphere to produce an anode active material.

[0212] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0213] Comparative Example 9

[0214] A positive electrode active material and a coin-type half-cell were manufactured in substantially the same manner as Comparative Example 8, except that in the manufacture of the positive electrode active material, the aluminum content in the aluminum nitrate hydrate was added in an amount of 1.0 mol% relative to 100 mol% of the total metal excluding lithium in the finally manufactured positive electrode active material.

[0215] Comparative Example 10

[0216] In the preparation of the positive active material, the positive active material and the coin-type half-cell were prepared in substantially the same manner as in Example 10, except that the mixer was heated to 450°C instead of 380°C to perform drying and coating simultaneously.

[0217] Comparative Example 11

[0218] A washed product identical to that prepared in Example 14 was introduced into a mixer (Rödige), and while mixing at a speed of 5 RPM, the temperature of the mixer was raised to 380°C and dried for a total of 5 hours to produce a dried product.

[0219] The above dried product and boronic acid (H3BO3) were mixed, and a second heat treatment was performed at 400°C for 8 hours in an oxygen atmosphere to produce a positive electrode active material. At this time, the boron content in the boronic acid was added in an amount of 0.25 mol% relative to 100 mol% of the total metal excluding lithium in the finally produced positive electrode active material.

[0220] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0221] Comparative Example 12

[0222] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as Comparative Example 11, except that the boron content in the boron acid was added in an amount of 0.5 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0223] Comparative Example 13

[0224] A positive electrode active material and a coin-type half-cell were prepared in substantially the same manner as Comparative Example 11, except that the boron content in the boron acid was added in an amount of 1.0 mol% relative to 100 mol% of the total metal excluding lithium in the positive electrode active material.

[0225] Comparative Example 14

[0226] 600g of distilled water and boronic acid were added to a 1L reactor, and a coating solution was prepared by stirring at approximately 350 rpm for about 5 minutes for salt dissolution. It was confirmed that the salt was completely dissolved in the coating solution and that it was colorless and transparent. 500g of the same dried product prepared in Comparative Example 11 was added to the coating solution being continuously stirred for 1.5 minutes, and stirred for about 30 minutes. At this time, the boron content in the boronic acid was designed to be 0.25 mol% relative to 100 wt% of the total metal excluding lithium in the finally prepared cathode active material.

[0227] The solvent was removed from the mixed solution using an aspirator and a filter press, and the product was vacuum dried at 190°C to obtain a coated product.

[0228] The above-mentioned coating product was subjected to a second heat treatment at 750°C for 8 hours in an oxygen atmosphere to produce an anode active material.

[0229] Subsequently, a coin-type half-cell was manufactured using substantially the same method as in Example 1.

[0230] Comparative Example 15

[0231] In the preparation of the positive active material, the positive active material and coin-type half-cell were prepared in substantially the same manner as in Example 14, except that the mixer was heated to 450°C instead of 380°C to perform drying and coating simultaneously.

[0232] The aluminum content in the aluminum raw material used in the manufacture of the cathode active material according to the examples and comparative examples is shown in Table 1 below.

[0233]

[0234] Evaluation Example 1: Initial Charge / Discharge Capacity and Efficiency

[0235] The lithium secondary batteries prepared in the examples and comparative examples were charged at 25°C with a constant current of 0.2C to an upper voltage limit of 4.55V and with a constant voltage of 0.05C, and then discharged at 0.2C to a cutoff voltage of 3.0V to perform initial charge and discharge. Table 1 below shows the initial charge capacity, initial discharge capacity, and the ratio of the latter to the former calculated as efficiency.

[0236] Evaluation Example 2: -20℃ capacity

[0237] The lithium secondary batteries prepared in the examples and comparative examples were charged at 25°C with a constant current of 0.2C to an upper voltage limit of 4.25V and with a constant voltage of 0.05C, and then discharged at 0.2C to a cutoff voltage of 3.0V to perform initial charging and discharging. Additionally, after charging at 25°C with a constant current of 0.2C to an upper voltage limit of 4.25V and with a constant voltage of 0.05C, discharged at -20°C with 0.2C to a cutoff voltage of 3.0V, and the discharge capacity at this time is shown as the discharge capacity in Table 1 below.

[0238] Evaluation Example 3: High-temperature life

[0239] Following the initial charge and discharge of Evaluation Example 1, a cycle of charging at 1.0C and discharging at 1.0C was repeated 50 times or more in a voltage range of 3.0V to 4.55V at 45℃, and the ratio of the 50-cycle discharge capacity to the initial discharge capacity was calculated and shown as the lifespan in Table 1 below.

[0240] Evaluation Example 4: Dose Recovery Rate

[0241] The lithium secondary batteries prepared in the examples and comparative examples were subjected to one charge-discharge cycle at 0.3C, and the discharge capacity was measured. Subsequently, the obtained batteries were stored at a high temperature (45℃) for 7 days, and then subjected to one charge-discharge cycle at 0.3C to measure the discharge capacity. The ratio of the discharge capacity after 7 days of storage to the discharge capacity before high-temperature storage was calculated, and the results are shown as the capacity recovery rate in Table 1 below.

[0242] Evaluation Example 5: Energy Density

[0243] The lithium secondary batteries prepared in the examples and comparative examples were charged and discharged at 25°C with a rate limit of 0.2C / 0.2C in a voltage range of 3.0V to 4.45V to calculate the energy density, which is shown in Table 1 below. The energy density was calculated using the formula {(average driving voltage (V) x capacity (Ah)) / cell weight (kg)}, where the capacity was calculated by multiplying the positive electrode volume (cc) by the discharge capacity (Ah / cc).

[0244] Al (mol%) B (mol%) Initial Charge Capacity (mAh / g) Initial Discharge Capacity (mAh / g) Efficiency (%) Discharge Capacity (mAh / g) Lifetime (%) Capacity Recovery Rate (%) Energy Density (Wh / kg) Example 1 0.1-245.6211.786.216095.279.4776 Example 20.2-245.2211.186.115895.379.9785 Example 30.3-244.9210.686.015895.379.7783 Example 40.5-244.5210.085.915694.779.2783 Example 50.1-245.4211.386.115995.178.4776 Example 60.2-245.2210.986.015895.379.0785 Example 70.3-245.0210.786.015895.478.9783 Example 80.5-244.2209.585.815594.878.4783 Example 90.1-231.1196.184.912284.678.9743 Example 100.2-230.8195.784.812189.182.1742 Example 110.3-230.5195.484.812188.481.9741 Example 120.4-229.9194.384.511886.281.3742 Example 130.5-229.4193.684.411584.181.2740 Example 14-0.25244.2212.587.016797.180.4776 Example 15-0.5244.8215.187.917097.681.0785 Example 16-1.0243.9214.688.017097.580.9783 Comparative Example 10.1-245.2209.285.315085.062.0766 Comparative Example 20.2-244.7208.285.114984.862.3760 Comparative Example 30.3-244.3207.484.914584.562.4751 Comparative Example 40.5-243.6205.884.514084.161.9743 Comparative Example 50.2-243.1208.385.715393.170.4752 Comparative Example 60.2-243.9209.385.815490.674.3755 Comparative Example 70.5-229.7195.685.211575.175.0741 Comparative Example 80.2-229.6194.584.911785.280.9739 Comparative Example 91.0-229.1195.285.211480.981.2742 Comparative Example 100.2-228.9192.183.910583.272.2741 Comparative Example 11-0.25242.1210.687.016296.578.2771 Comparative Example 12-0.5242.9213.587.916396.978.9779 Comparative Example 13-1.0243.1213.988.016597.078.9781 Comparative Example 14-0.25241.3209.586.815895.374.3765 Comparative Example 15-0.25240.1208.486.815693.272.1761.

[0245] Referring to Table 1, it can be seen that the initial charge / discharge capacity, efficiency, capacity recovery rate, and lifespan characteristics are superior in Examples 1 to 4, in which an aluminum coating layer is formed by a wet coating method during mixer operation after a cleaning process using aluminum nitrate, compared to Comparative Examples 1 to 4, in which an aluminum coating layer is formed through dry coating of the cleaned product, Comparative Example 5, in which an aluminum coating layer is formed by a wet method on the cleaned product but drying and a second heat treatment are performed as separate processes, and Comparative Example 6, in which drying and coating are performed at a high temperature. In particular, according to Example 2, when the aluminum content in the aluminum nitrate is added in an amount of 0.2 mol% relative to 100 mol% of the total metal excluding lithium in the cathode active material, it can be seen that the efficiency, capacity, capacity recovery rate, and lifespan characteristics are the best.

[0246] In addition, in the case of Examples 5 to 8, in which an aluminum coating layer is formed by a wet coating method during the operation of a mixer after a cleaning process using aluminum sulfate, it can be confirmed that the initial charge / discharge capacity, efficiency, capacity recovery rate, and lifespan characteristics are superior compared to Comparative Examples 1 to 4, in which an aluminum coating layer is formed through dry coating of the cleaned product; Comparative Example 5, in which an aluminum coating layer is formed by wet coating of the cleaned product but drying and a second heat treatment are performed as separate processes; and Comparative Example 6, in which drying and coating are performed at a low temperature.

[0247] In addition, in the case of Examples 9 to 13, in which an aluminum coating layer is formed by a wet coating method during the operation of a mixer after a cleaning process using aluminum nitrate hydrate, it can be confirmed that the initial charge / discharge capacity, efficiency, capacity recovery rate, and lifespan characteristics are superior compared to Comparative Example 7, in which an aluminum coating layer is formed through dry coating of the cleaned product; Comparative Examples 8 and 9, in which an aluminum coating layer is formed by wet coating of the cleaned product but drying and a second heat treatment are performed as separate processes; and Comparative Example 10, in which drying and coating are performed at a high temperature.

[0248] In addition, in the case of Examples 14 to 16, in which a boron coating layer is formed by a wet coating method during the operation of a mixer after a cleaning process using boron acid, it can be confirmed that the initial charge / discharge capacity, efficiency, capacity recovery rate, and lifespan characteristics are superior compared to Comparative Examples 11 to 13, in which a boron coating layer is formed through dry coating of the cleaned product; Comparative Example 14, in which a boron coating layer is formed by a wet method on the cleaned product but drying and a second heat treatment are performed as separate processes; and Comparative Example 15, in which drying and coating are performed at a high temperature.

[0249] Although preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts defined in the following claims are also included within the scope of the present invention.

[0250] [Explanation of the symbol]

[0251] 100: Lithium secondary battery 10: Positive electrode

[0252] 11: Positive lead tab 12: Positive terminal

[0253] 20: Cathode 21: Cathode lead tab

[0254] 22: Negative terminal 30: Separator

[0255] 40: Electrode assembly 50: Case

[0256] 60: Sealing member 70: Electrode tab

[0257] 71: Positive tab 72: Negative tab

Claims

(1) A step of preparing core particles containing lithium nickel-based composite oxide; (2) A step of cleaning the core particles by mixing the core particles with cleaning water; (3) A step of obtaining a cleaned product by removing a portion of the cleaning water such that the cleaning water is included in an amount of 1% to 10% by weight relative to the total 100% by weight of the core particles and cleaning water; and (4) A step of introducing the above-mentioned cleaning product and aluminum raw material or boron raw material into a mixer and heat-treating at 300°C to 400°C; a method for manufacturing an anode active material. In paragraph 1, The above lithium nickel-based composite oxide is a method for manufacturing a positive electrode active material represented by the following chemical formula 3: [Chemical Formula 3] Li a3 Ni x3 M 4 y3 M 5 z3 O 2-b3 X b3 In Chemical Formula 3, 0.9≤a3≤1.8, 0.3≤x3≤1, 0≤y3≤0.7, 0≤z3≤0.7, 0.9≤x3+y3+z3≤1.1, and 0≤b3≤0.1, and M 4 and M 5 is each independently one or more elements selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and M 4 and M 5 are distinct elements, and X is one or more elements selected from F, P, and S. In paragraph 1, A method for manufacturing a positive electrode active material in which the nickel content is 60 mol% or more based on 100 mol% of the total metal excluding lithium in the above lithium-nickel-based composite oxide. In paragraph 1, The above-mentioned core particle is in the form of a secondary particle formed by the aggregation of a plurality of primary particles, and Average particle size (D of the above core particles) 50 ) is a method for manufacturing a positive electrode active material having a thickness of 8 μm to 15 μm. In paragraph 1, A method for manufacturing an anode active material, wherein, in the step of cleaning the core particles, the core particles and cleaning water are mixed in a weight ratio of 0.5:1 to 1:

1. In paragraph 1, The above aluminum raw material includes aluminum sulfate, aluminum sulfate hydrate, aluminum nitrate, aluminum nitrate hydrate, or a combination thereof, and A method for manufacturing an anode active material comprising the above boron raw material, boronic acid, boron sulfate, boron nitride, or a combination thereof. In paragraph 1, In the above step (4), the aluminum raw material is fed into the mixer, and A method for manufacturing a positive electrode active material in which the aluminum content in the aluminum raw material is 0.1 mol% to 1.0 mol% based on 100 mol% of the total sum of the metal excluding lithium in the core particles and the aluminum of the aluminum raw material. In paragraph 1, In the above step (4), the boron raw material is fed into the mixer, A method for manufacturing an anode active material in which the boron content of the boron raw material is 0.1 mol% to 3.0 mol% based on the total metal excluding lithium in the core particles and the total boron of the boron raw material being 100 mol%. In paragraph 1, The above mixer is a method for manufacturing a positive electrode active material by mixing at a speed of 50 RPM or less. In paragraph 1, A method for manufacturing a positive electrode active material in which the heat treatment temperature of step (4) above is 350℃ to 390℃. A positive active material manufactured by a manufacturing method according to any one of claims 1 to 10. In Paragraph 11, The above positive active material comprises core particles containing a lithium nickel-based composite oxide; and A positive active material comprising a coating layer containing aluminum or boron located on the surface of the core particle. In Paragraph 12, The above-mentioned core particle is in the form of a secondary particle formed by the aggregation of a plurality of primary particles, and Average particle size (D of the above core particles) 50 ) is a positive active material having a size of 8 μm to 15 μm. In Paragraph 12, The above coating layer includes aluminum, and A positive electrode active material having an aluminum content of 0.1 mol% to 1.0 mol% based on 100 mol% of total metal excluding lithium on the surface of the positive electrode active material, as measured by SEM-EDS on the surface of the positive electrode active material. In Paragraph 12, A positive active material having a coating layer thickness of 5 nm to 200 nm. In Paragraph 12, The above coating layer is a positive active material in the form of a film that continuously surrounds the surface of the core particle. Anode comprising a positive active material according to Clause 11; cathode; and A lithium secondary battery containing an electrolyte.

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