Positive electrode active material precursor and method for manufacturing positive electrode active material precursor

Abstract

The present invention relates to a method for manufacturing a positive electrode active material precursor having excellent sphericity, a uniform particle size distribution, and reduced particle agglomeration by carrying out a reaction for manufacturing a positive electrode active material precursor seed in a continuous stirred tank reactor (CSTR), and introducing the manufactured precursor seed into a batch reactor and growing same, wherein a positive electrode active material precursor particle seed introduced into the batch reactor is introduced in an appropriate amount.

Description

Positive electrode active material precursor and method for producing positive electrode active material precursor

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 2024-0006138, filed January 15, 2024, the entire contents of which are incorporated herein by reference.

[0003]

[0004] Technology field

[0005] The present invention relates to a positive electrode active material precursor and a method for producing a positive electrode active material precursor.

[0006]

[0007] With the increasing technological development and demand for mobile devices and electric vehicles, the demand for secondary batteries as an energy source is rapidly increasing. Among secondary batteries, lithium secondary batteries, which boast high energy density and voltage, long cycle life, and low self-discharge rates, are commercialized and widely used.

[0008] Lithium composite transition metal oxides are used as positive electrode active materials for lithium secondary batteries, and with the recent increase in demand for vehicle batteries requiring long-distance driving capabilities, lithium nickel cobalt manganese metal oxides with high nickel content are being actively developed to secure high capacity.

[0009] While higher nickel content is advantageous for securing high capacity, it also presents challenges such as reduced structural stability, chemical stability, and thermal stability. To address this, the development of single-particle cathode active materials and those with various diameters is underway. To ensure consistent quality in single-particle cathode active materials and those with various diameters, heat must be evenly and effectively transferred during the sintering process of the cathode active material precursor. To ensure even and effective heat transfer, the cathode active material precursor must have a small, uniform particle size and high sphericity.

[0010] Meanwhile, representative methods for manufacturing a cathode active material precursor, which is a raw material for a cathode material, include a method of manufacturing a cathode active material precursor using a continuous stirring tank reactor (CSTR) and a method of manufacturing a cathode active material precursor using a batch reactor.

[0011] Cathode active material precursors manufactured using a continuous stirred tank reactor have high productivity through a continuous process, but have a broad particle size distribution, while precursors manufactured using a batch reactor have relatively low productivity and a narrow particle size distribution. However, when manufacturing precursors using a batch reactor, it is difficult to reproduce or predict the same particle size distribution and average particle size for each reaction because the precursor seed formation step and precursor particle growth step occur simultaneously within the reactor. In addition, when mass-producing using a batch reactor, the larger the reactor, the higher the speed at which the stirrer must rotate, which poses difficulties in terms of equipment, and the particle size distribution of the seeds broadens, which also broadens the final particle size distribution.

[0012] Accordingly, a method for reproducibly manufacturing a positive electrode active material precursor having a uniform particle size is required.

[0013]

[0014] [Prior Art Literature]

[0015] [Patent Document]

[0016] (Patent Document 1) CN 111196613 B

[0017]

[0018] The problem to be solved by the present invention is to provide a method for manufacturing a positive electrode active material precursor having excellent sphericity, uniform particle size distribution, and reduced particle agglomeration.

[0019]

[0020] (1) The present invention provides a positive electrode active material precursor having a ratio of multi-particles having an average sphericity value of 0.73 or more and 1.0 or less according to the following mathematical formula 1, a span value of 0.4 or more and 0.9 or less according to the following mathematical formula 4, and an aspect ratio value of less than 1.4 obtained by shape analysis of an SEM image, of 6% or less.

[0021] [Mathematical Formula 1]

[0022]

[0023] In the above mathematical formula 1,

[0024] A is the area of ​​the particle measured by shape analysis of the SEM image,

[0025] P is the perimeter of the particle measured by shape analysis of the SEM image.

[0026] [Equation 4]

[0027] Span = (D 95 - D5) / D 50

[0028] (2) The present invention provides a positive electrode active material precursor having a span value according to the above mathematical formula 1 of 0.60 or more and 0.85 or less in the above (1).

[0029] (3) The present invention provides a positive electrode active material precursor having a multi-particle ratio of 4% or less in (1) or (2).

[0030] (4) The present invention provides a positive electrode active material precursor having an average value of the sphericity of 0.75 or more and 0.90 or less in any one of the above (1) to (3).

[0031] (5) The present invention relates to an average particle diameter (D) in any one of the above (1) to (4) 50 ) provides a positive electrode active material precursor having a diameter of 2 ㎛ or more and 11 ㎛ or less.

[0032] (6) The present invention provides a method for producing a positive electrode active material precursor, comprising the steps of: (S1) continuously introducing a transition metal-containing solution, an ammonium cation complex forming agent, and an alkaline aqueous solution into a continuous stirred tank reactor (CSTR) and mixing them to produce a seed solution containing a positive electrode active material precursor seed; and (S2) introducing the seed solution prepared in step (S1) into a batch reactor, stirring the seed solution, and then introducing the transition metal-containing solution, the ammonium cation complex forming agent, and the alkaline aqueous solution to grow positive electrode active material precursor particles, wherein the content of the positive electrode active material precursor seed included in the seed solution introduced into the batch reactor in step (S2) is 4% or more and 11% or less of the theoretical yield of the positive electrode active material precursor to be finally produced.

[0033] (7) The present invention provides a method for producing a positive electrode active material precursor, wherein, in the above (6), the content of the positive electrode active material precursor seed included in the seed solution fed into the batch reactor in the above (S2) step is 4% or more and 9% or less of the theoretical yield of the positive electrode active material precursor to be finally produced.

[0034] (8) The present invention provides a method for producing a positive electrode active material precursor in the step (6) or (7), wherein the concentration of the ammonium cation complex forming agent in the reactant and the pH of the reactant in the step (S2) are controlled in the same manner as in the step (S1).

[0035] (9) The present invention provides a cathode active material which is a sintered product of a mixture of a cathode active material precursor according to any one of (1) to (5) and a lithium raw material.

[0036] (10) The present invention provides a lithium secondary battery including a positive electrode active material according to (9).

[0037]

[0038] According to the method for manufacturing a positive electrode active material precursor of the present invention, a positive electrode active material precursor having a uniform particle size, high sphericity, and reduced particle agglomeration can be provided.

[0039]

[0040] Figure 1 is a SEM image (2k) showing the positive electrode active material precursor manufactured in Example 1.

[0041] Figure 2 is a SEM image (2k) showing the positive electrode active material precursor manufactured in Example 2.

[0042] Figure 3 is an SEM image (2k) showing the positive electrode active material precursor manufactured in Comparative Example 1.

[0043] Figure 4 is an SEM image (2k) showing the positive electrode active material precursor manufactured in Comparative Example 2.

[0044]

[0045] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0046] Terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0047]

[0048] In this specification, a primary particle refers to the smallest unit particle observed when measuring with a scanning electron microscope (SEM). A secondary particle refers to an aggregate, i.e., a secondary structure, formed by the physical or chemical bonding of primary particles together without any intentional aggregation or assembly process for the primary particles that constitute the secondary particle.

[0049]

[0050] In this specification, D5, D 50 and D 95 Each can be defined as a particle size corresponding to 5%, 50%, and 95% of the volume accumulation amount in the particle size distribution curve (graph curve of particle size distribution). The above D5, D 50 and D 95 For example, it can be measured using the laser diffraction method. The laser diffraction method can generally measure particle diameters from several nm to several mm, and can obtain results with high reproducibility and high resolution. In this specification, the average particle diameter is D 50 It means.

[0051]

[0052] In this specification, sphericity is a value obtained by shape analysis of a scanning electron microscope (SEM) image, and can be calculated from the ratio between the square of the area and the perimeter. Specifically, sphericity is a value calculated by measuring the planar area (A) and planar perimeter (P) of each particle in the SEM image through shape analysis of the SEM image, and then substituting the results into the following mathematical equation (1).

[0053] [Mathematical Formula 1]

[0054]

[0055] The closer the sphericity is to 1, the closer it is to a circle.

[0056] Meanwhile, the sphericity can be maintained within the error range regardless of the magnification of the SEM image.

[0057]

[0058] In this specification, the tap density is the apparent density of particles obtained by filling 50 g of a positive electrode active material precursor in a 100 ml container and then vibrating (tapping more than 3000 times) under certain conditions (stroke of 10 to 50 mm), and can be measured using a tap density tester (KYT-4000, Seishin Corporation).

[0059]

[0060] In this specification, pH is the pH value measured at any temperature converted to a 25°C pH value by substituting it into the conversion formula represented by the following mathematical formula 2.

[0061] [Equation 2]

[0062] pH(25℃) = (measurement temperature-50)*0.0333 + 0.8325 + measured pH

[0063]

[0064] In this specification, “precursor multi-particle” means a particle with an aspect ratio of 1.4 or greater. In principle, a multi-particle is not a single particle, but rather an agglomeration of multiple particles. However, in the precursor formation reaction, fine particles grow by agglomerating from the beginning of the reaction, and as growth continues, they gradually change to resemble a single particle. Therefore, after sufficient particle growth has occurred in the precursor formation reaction, it is difficult to distinguish the manufactured precursors into multi-particles and single particles in the fundamental sense. However, when analyzing SEM images, the initial growth of fine particles by agglomeration and the growth without agglomeration are clearly distinguishable with the naked eye. Therefore, in this specification, particles with an aspect ratio of 1.4 or greater are defined as multi-particles in order to distinguish between the initial growth of fine particles by agglomeration and the growth without agglomeration.

[0065] Meanwhile, the aspect ratio of the particle is a value obtained by shape analysis of the SEM image, and can be defined as the ratio of the major axis length to the minor axis length on the plane shown in the cross-section of the positive electrode active material precursor particle, i.e., the SEM image. Specifically, the dispersion of the outer points of the particle (λ1 2 ) is called the major axis, and the dispersion of the outer points of the particle (λ2) 2 ) is the short axis, the aspect ratio is λ1 / λ2. The aspect ratio can be maintained within the margin of error regardless of the magnification of the SEM image.

[0066]

[0067] <Method for producing a cathode active material precursor>

[0068] The present invention provides a method for manufacturing a positive electrode active material precursor.

[0069] A method for producing a positive electrode active material precursor according to one embodiment of the present invention comprises the steps of: (S1) continuously introducing a transition metal-containing solution, an ammonium cation complex forming agent, and a basic aqueous solution into a continuous stirred tank reactor (CSTR) and mixing them to produce a seed solution containing positive electrode active material precursor seeds; and (S2) introducing the seed solution prepared in step (S1) into a batch reactor to grow positive electrode active material precursor particles, wherein the content of the positive electrode active material precursor seed included in the seed solution introduced into the batch reactor in step (S2) is 4% or more and 11% or less of the theoretical yield of the positive electrode active material precursor to be finally produced.

[0070] The present inventors performed a reaction for producing a positive electrode active material precursor seed in a continuous stirred tank reactor (CSTR), and fed the produced precursor seed into a batch reactor for growth. When the content of the positive electrode active material precursor particle seed fed into the batch reactor satisfies an appropriate amount, they discovered that a positive electrode active material precursor having excellent sphericity, uniform particle size distribution, and reduced particle agglomeration was produced, thereby completing the present invention.

[0071] Hereinafter, each step of a method for manufacturing a positive electrode active material precursor according to one embodiment of the present invention will be described.

[0072]

[0073] 1. (S1) Step

[0074] According to one embodiment of the present invention, the step (S1) may be a step of continuously introducing and mixing a transition metal-containing solution, an ammonium cation complex forming agent, and a basic aqueous solution into a continuous stirred tank reactor (CSTR) to prepare a seed solution including positive electrode active material precursor particle seeds.

[0075]

[0076] According to one embodiment of the present invention, the transition metal-containing solution may include cations of one or more metals selected from nickel (Ni), manganese (Mn), cobalt (Co), tungsten (W), molybdenum (Mo), chromium (Cr), and aluminum (Al). The metal ion-containing solution may include acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide of the metals, and is not particularly limited as long as it can be dissolved in water.

[0077] For example, the cobalt (Co) may be included as Co(OH)2, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O, CoSO4 or Co(SO4)2ㆍ7H2O, and any one or a mixture of two or more thereof may be used. In addition, the nickel (Ni) may be included as Ni(OH)2, NiO, NiOOH, NiCO3ㆍ2Ni(OH)2ㆍ4H2O, NiC2O2ㆍ2H2O, Ni(NO3)2ㆍ6H2O, NiSO4, NiSO4ㆍ6H2O, fatty acid nickel salts or nickel halides, and any one or a mixture of two or more thereof may be used. In addition, the manganese (Mn) may be included as manganese oxides such as Mn2O3, MnO2, and Mn3O4; Manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylic acid salts, manganese citrate and manganese fatty acid salts; oxyhydroxides, and manganese chloride, any one of which or a mixture of two or more thereof may be used.

[0078] Meanwhile, if the precursor finally manufactured further contains other doping elements (M) in addition to nickel (Ni), manganese (Mn), cobalt (Co), tungsten (W), molybdenum (Mo), chromium (Cr), and aluminum (Al) (for example, M is at least one element selected from Zr, Ti, Mg, Ta, and Nb), the doping element-containing raw material may be further optionally added during the manufacture of the transition metal-containing solution. Examples of the doping element-containing raw material include acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide containing the doping element, and one of these may be used alone or a mixture of two or more thereof. For example, if the doping element is Zr, zirconium oxide or the like may be used.

[0079]

[0080] According to one embodiment of the present invention, the ammonium cation complex forming agent may include at least one selected from NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, and NH4CO3. As the solvent, water or a mixture of water and an organic solvent (specifically, alcohol, etc.) that is uniformly miscible with water may be used.

[0081]

[0082] According to one embodiment of the present invention, the basic aqueous solution may include at least one selected from an alkali metal hydrate, an alkali metal hydroxide, an alkaline earth metal hydrate, and an alkaline earth metal hydroxide. For example, the basic aqueous solution may include NaOH, KOH, Ca(OH)2, etc., and as the solvent, water or a mixture of water and an organic solvent (specifically, alcohol, etc.) that can be uniformly mixed with water may be used.

[0083]

[0084] According to one embodiment of the present invention, the content of the ammonium cation complex forming agent introduced in the step (S1) may be 4 parts by weight to 100 parts by weight, and preferably 4 parts by weight to 30 parts by weight, based on 100 parts by weight of the transition metal-containing solution introduced in the step (S1).

[0085] Meanwhile, the above step (S1) may be performed at a pH of 11.3 to 14.5 of the reaction solution, preferably at a pH of 11.4 to 14, and more specifically at a pH of 11.4 to 12.5. The above basic aqueous solution may be used to control the pH of the reaction solution. When the content of the ammonium cation complex forming agent added in the above step (S1) is within the above range or the pH of the reaction solution is within the above range, it may be advantageous to control the size of the seeds.

[0086]

[0087] According to one embodiment of the present invention, the average particle diameter (D) of the positive electrode active material precursor seed 50 ) is the average particle diameter (D) of the positive electrode active material precursor particles that are finally manufactured. 50 ) can be 20% to 70% in size. Specifically, the average particle diameter (D) of the positive electrode active material precursor seed 50 ) may be 0.5 ㎛ to 6 ㎛, preferably 1 ㎛ to 5.5 ㎛ or 1.5 ㎛ to 5 ㎛. When the seed size is within the above range, the particle size of the formed positive electrode active material precursor seed may be uniform, and thus, a positive electrode active material precursor having a narrow particle size distribution may be reproducibly manufactured.

[0088]

[0089] According to one embodiment of the present invention, the mixing in step (S1) may be performed at a temperature of 10°C to 80°C. Specifically, it may be performed at a temperature of 30°C to 60°C, more specifically, at a temperature of 50°C to 60°C. When the temperature conditions are within the above range, the transition metal ions can be sufficiently dissolved while preventing the introduced solutions from volatilizing, so that the positive electrode active material precursor seed can be properly formed.

[0090]

[0091] 2. S2 stage

[0092] According to one embodiment of the present invention, the step (S2) may be a step of introducing the seed solution prepared in the step (S1) into a batch reactor, stirring the mixture, and then introducing a transition metal-containing solution, an ammonium cation complex forming agent, and a basic aqueous solution to grow positive electrode active material precursor particles.

[0093] According to one embodiment of the present invention, before introducing the seed solution into the batch reactor in the step (S2), the batch reactor may be purged with an inert gas, for example, nitrogen, to remove dissolved oxygen and create a non-oxidizing atmosphere.

[0094]

[0095] According to one embodiment of the present invention, after the batch reactor is set to a non-oxidizing atmosphere in the step (S2), the seed solution can be introduced.

[0096] According to one embodiment of the present invention, the content of the positive electrode active material precursor seed transferred to the batch reactor in the step (S2) may be 4% or more and 11% or less of the theoretical yield of the positive electrode active material precursor to be finally manufactured, and specifically, 4% or more and 9% or less. Specifically, the content of the positive electrode active material precursor seed transferred to the batch reactor in the step (S2) may be 4.0% or more and 10.5% or less, 10.0% or less, 9.5% or less, or 9.0% or less of the theoretical yield of the positive electrode active material precursor to be finally manufactured.

[0097] If the content of the positive electrode active material precursor seed transferred to the batch reactor in the above step (S2) satisfies the above range, a positive electrode active material precursor having excellent sphericity, uniform particle size distribution, and alleviated particle agglomeration can be manufactured. If the content of the positive electrode active material precursor seed transferred to the batch reactor in the above step (S2) is less than the above range, the growth of the average particle diameter becomes very fast and cannot grow for a sufficient period of time, resulting in a decrease in sphericity. If it is more than the above range, agglomeration of particles occurs, resulting in a decrease in sphericity.

[0098] Meanwhile, the theoretical yield of the positive electrode active material precursor finally manufactured refers to the yield of the positive electrode active material precursor obtained when the positive electrode active material precursor seed is grown for 24 hours in the step (S2). Specifically, the theoretical yield of the positive electrode active material precursor finally manufactured can be calculated using the following mathematical formula 3.

[0099] [Equation 3]

[0100] Theoretical yield of positive electrode active material precursor = Flow rate of transition metal solution per hour (L / hr) * Reaction time (24 hr) * Concentration of transition metal solution (mol / L) * Mol mass of positive electrode active material precursor (g / mol)

[0101]

[0102] Thereafter, the seed solution can be stirred at a rotation speed of 700 rpm or more and 1000 rpm or less under temperature conditions of 10°C to 80°C.

[0103] According to one embodiment of the present invention, the stirring in step (S2) may be performed at a temperature of 10°C to 80°C. Specifically, it may be performed at a temperature of 30°C to 60°C, and more specifically, at a temperature of 50°C to 60°C. When the temperature conditions are within the above range, the transition metal ions can be sufficiently dissolved while preventing the introduced solutions from volatilizing, so that the positive electrode active material precursor particles can be easily formed.

[0104] According to one embodiment of the present invention, the stirring in step (S2) may be performed at a rotation speed of 30 rpm or more and 1,000 rpm or less. Specifically, it may be performed at a rotation speed of 750 rpm or more and 950 rpm or less, and more specifically, at a rotation speed of 800 rpm or more and 900 rpm or less. When the rotation speed is within the above range, the transition metal ions can be sufficiently dissolved while preventing the introduced solutions from volatilizing, so that the positive electrode active material precursor particles can be easily formed.

[0105] According to one embodiment of the present invention, the stirring in the step (S2) may be performed for 10 minutes to 1 hour. The stirring time within the above range may be such that the average particle diameter (D) of the positive electrode active material precursor particles is targeted. 50 ) is the time required to grow. If the execution time is within the above range, cathode active material precursor particles with a narrow particle distribution can be economically manufactured.

[0106]

[0107] Meanwhile, in the step (S2), after stirring the seed solution, a transition metal solution, an ammonium ion-containing solution, and a basic aqueous solution are additionally mixed to grow positive electrode active material precursor particles. The transition metal ion-containing solution, ammonium ion-containing solution, and basic aqueous solution introduced in the step (S2) have been described in the step (S1), and therefore, a detailed description thereof will be omitted below.

[0108] As described above, when the transition metal solution, the ammonium ion-containing solution, and the basic aqueous solution are additionally mixed after stirring the seed solution, the stirring of the batch reactor may be performed at a rotation speed of 500 rpm or more and 650 rpm or less. Accordingly, the growth of the positive electrode active material precursor particles can be smoothly achieved.

[0109] As described above, when the transition metal solution, the ammonium ion-containing solution, and the basic aqueous solution are additionally mixed after stirring the seed solution, the reaction may be performed at a pH of 11 to 14.5, preferably 11.2 to 14, and more specifically 11.4 to 12.8. When the pH of the reaction solution is within the above range in the step (S2), it may be advantageous to uniformly control the size of the positive electrode active material precursor particles.

[0110]

[0111] The reaction for growing the positive electrode active material precursor particles in the above step (S2) may be performed for 10 to 100 hours. The reaction time within the above range is the average particle diameter (D) targeting the size of the positive electrode active material precursor particles. 50 ) is the time required to grow. If the execution time is within the above range, cathode active material precursor particles with a narrow particle distribution can be economically manufactured.

[0112]

[0113] According to one embodiment of the present invention, the concentration of the ammonium cation complex forming agent in the reactants and the pH of the reactants in step (S2) can be controlled in the same manner as in step (S1). In this case, the growth of the positive electrode active material precursor can be achieved more easily.

[0114]

[0115] <Cathode active material precursor>

[0116] The present invention provides a positive electrode active material precursor manufactured by the method for manufacturing the positive electrode active material precursor.

[0117] According to one embodiment of the present invention, the positive electrode active material precursor has a ratio of multi-particles having an average sphericity value of 0.73 or more and 1.0 or less according to the following mathematical formula 1, a span value of 0.4 or more and 0.9 or less according to the following mathematical formula 4, and an aspect ratio value of less than 1.4 obtained by shape analysis of an SEM image, of 6% or less.

[0118] [Mathematical Formula 1]

[0119]

[0120] In the above mathematical formula 1,

[0121] A is the area of ​​the particle measured by shape analysis of the SEM image,

[0122] P is the perimeter of the particle measured by shape analysis of the SEM image.

[0123] [Equation 4]

[0124] Span = (D 95 - D5) / D 50

[0125]

[0126] In this specification, the average value of the sphericity of the positive electrode active material precursor means the average value obtained by measuring the sphericity of each particle of the positive electrode active material precursor.

[0127]

[0128] In this specification, D5, D 50 and D 95 Each can be defined as a particle size corresponding to 5%, 50%, and 95% of the volume accumulation amount in the particle size distribution curve (graph curve of particle size distribution). The above D5, D 50 and D 95 For example, it can be measured using a laser diffraction method. The laser diffraction method can generally measure particle diameters ranging from several nm to several mm, and can obtain results with high reproducibility and high resolution.

[0129]

[0130] According to one embodiment of the present invention, a cathode active material precursor may have a uniform particle size, a high sphericity, and a multi-particle ratio of 6% or less. Accordingly, the uniformity of cathode material sintering may be improved, thereby reducing Li byproducts and enhancing cathode material performance.

[0131] According to one embodiment of the present invention, the positive electrode active material precursor may have a span value according to the above mathematical formula 1 of 0.40 or more and 0.87 or less, and as specific examples, may be 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more, 0.7 or more, or 0.75 or more, and may also be 0.89 or less, 0.88 or less, 0.87 or less, 0.86 or less, or 0.85 or less.

[0132] According to one embodiment of the present invention, the average value of the sphericity of the positive electrode active material precursor may be 0.73 or more and 1.0 or less, and for specific examples, may be 0.732 or more, 0.734 or more, 0.736 or more, 0.738 or more, or 0.74 or more, and further, may be 0.98 or less, 0.96 or less, 0.94 or less, 0.92 or less, or 0.90 or less.

[0133]

[0134] According to one embodiment of the present invention, the multi-particle ratio of the positive electrode active material precursor may be 6% or less, and for specific examples, 6.0% or less, 5.9% or less, 5.8% or less, 5.7% or less, or 5.6% or less, and may be 0.5% or more, 1% or more, 1.5% or more, or 2% or more.

[0135]

[0136] According to one embodiment of the present invention, the average particle diameter (D) of the positive electrode active material precursor 50 ) may be 2 ㎛ or more and 11 ㎛ or less, and as a specific example, may be 2.5 ㎛ or more, 3 ㎛ or more, 3.5 ㎛ or more, or 4 ㎛ or more.

[0137]

[0138] According to one embodiment of the present invention, the positive electrode active material precursor may have a composition represented by the following chemical formula 1 or chemical formula 2.

[0139] [Chemical Formula 1]

[0140] Ni a1 Co b1 Mn c1 Me d1 (OH)2

[0141] In the above chemical formula 1, Me is at least one selected from W, Al, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and 0.7≤a1<1.0, 0 <b1<0.3, 0<c1<0.3, 0≤d1≤0.02이며,

[0142] [Chemical Formula 2]

[0143] Ni a2 Co b2 Mn c2 Me d2 O·OH

[0144] In the above chemical formula 2, Me is at least one selected from W, Al, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and 0.7≤a2<1.0, 0 <b2<0.3, 0<c2<0.3, 0≤d2≤0.02이다.

[0145] According to one embodiment of the present invention, the positive electrode active material precursor may contain nickel (Ni) in an amount of 70 mol% or more, specifically 80 mol% or more, and more specifically 85 mol% or more, based on the total moles of metals excluding lithium.

[0146]

[0147] According to one embodiment of the present invention, the positive electrode active material precursor may have a tap density of 1.85 g / ml or more and 2.0 g / ml or less, specifically 1.87 g / ml to 1.99 g / ml, and more specifically 1.89 g / ml to 1.97 g / ml. In this case, since the tap density is high compared to the average particle size, the packing ratio can be increased during firing for manufacturing the positive electrode active material, thereby having the advantage of improving the productivity of the positive electrode active material.

[0148]

[0149] <Cathode active material>

[0150] The present invention provides a cathode active material which is a sintered product of a mixture of the cathode active material precursor and a lithium raw material.

[0151] According to one embodiment of the present invention, the positive electrode active material can be manufactured by mixing the positive electrode active material precursor of the present invention with a lithium raw material and then calcining it.

[0152] According to one embodiment of the present invention, the lithium raw material may be a lithium-containing carbonate (e.g., lithium carbonate, etc.), a hydrate (e.g., lithium hydroxide hydrate (LiOH·H2O)), a hydroxide (e.g., lithium hydroxide, etc.), a nitrate (e.g., lithium nitrate (LiNO3)), a chloride (e.g., lithium chloride (LiCl)), or a mixture of two or more thereof.

[0153] Meanwhile, the mixing of the positive electrode active material precursor and the lithium raw material can be achieved by solid-phase mixing, and the mixing ratio of the positive electrode active material precursor and the lithium raw material can be determined within a range that satisfies the atomic fraction of each component in the positive electrode active material to be finally manufactured.

[0154] According to one embodiment of the present invention, the positive electrode active material precursor and the lithium raw material may be mixed in an amount such that the molar ratio of transition metal:Li is 1:0.9 to 1:1.2, specifically 1:0.98 to 1:1.1. When the precursor and the lithium raw material are mixed within the above range, a positive electrode active material exhibiting excellent capacity characteristics can be manufactured.

[0155] According to one embodiment of the present invention, the firing may be performed at 600°C to 1000°C, specifically 700°C to 900°C, and the firing time may be 5 hours to 30 hours, specifically 8 hours to 15 hours.

[0156]

[0157] According to one embodiment of the present invention, the positive electrode active material may be manufactured from a positive electrode active material precursor according to the present invention and may be in the form of secondary particles.

[0158]

[0159] According to one embodiment of the present invention, the positive electrode active material may have a composition represented by the following chemical formula 3.

[0160] [Chemical Formula 3]

[0161] Li 1+x Ni a3 Co b3 M1 c3 M2 d3 O2

[0162] In the above chemical formula 3, the M1 is at least one selected from Mn and Al, the M2 is at least one selected from W, Cu, Fe, Ba, V, Cr, Ti, Zr, Zn, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, -0.2≤x≤0.2, 0.7≤a3<1.0, 0 <b3<0.3, 0<c3<0.3, 0≤d3≤0.02이다.

[0163] According to one embodiment of the present invention, the positive electrode active material may contain nickel (Ni) in an amount of 70 mol% or more, specifically 80 mol% or more, and more specifically 85 mol% or more, based on the total moles of metals excluding lithium.

[0164]

[0165] According to one embodiment of the present invention, the positive electrode active material may contain residual lithium in an amount of 0.8 wt% or less based on the total weight of the positive electrode active material. Accordingly, a lithium secondary battery including the positive electrode active material according to the present invention may exhibit excellent performance.

[0166]

[0167] Bipolar

[0168] The present invention provides a positive electrode comprising the positive electrode active material.

[0169] According to one embodiment of the present invention, the positive electrode includes a positive electrode current collector, a positive electrode active material layer formed on the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material according to the present invention.

[0170] Since the above positive electrode active material has been described above, a detailed description will be omitted, and only the remaining components will be described in detail below.

[0171] According to one embodiment of the present invention, the positive electrode current collector may include a highly conductive metal, and is not particularly limited as long as it is easily adhered to a positive electrode active material layer but does not react within the voltage range of the battery. The positive electrode current collector may be made of, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 μm, and fine unevenness may be formed on the surface of the current collector to increase the adhesive strength of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0172] According to one embodiment of the present invention, the positive electrode active material layer may optionally include a conductive material and a binder, together with the positive electrode active material, as needed.

[0173] At this time, the positive electrode active material may be included in an amount of 80 to 99 wt%, more specifically 85 to 98.5 wt%, based on the total weight of the positive electrode active material layer. When included in the above content range, excellent capacity characteristics can be exhibited.

[0174] According to one embodiment of the present invention, the conductive material is used to provide conductivity to the electrode, and in the battery to be formed, any conductive material that does not cause a chemical change and has electronic conductivity can be used without particular limitation. 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, thermal black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One of these may be used alone or a mixture of two or more may be used. The conductive material may be included in an amount of 0.1 to 15 wt% based on the total weight of the positive electrode active material layer.

[0175] According to one embodiment of the present invention, the binder serves to improve adhesion between positive electrode active material particles and adhesion between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylalcohol, polyacrylonitrile, polymethylmethaxrylate, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, polyacrylic acid, and polymers in which hydrogens of these are substituted with Li, Na, or Ca, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. The above binder may be included in an amount of 0.1 to 15 wt% based on the total weight of the positive electrode active material layer.

[0176] According to one embodiment of the present invention, the positive electrode can be manufactured according to a conventional positive electrode manufacturing method, except that the positive electrode active material described above is used. Specifically, the positive electrode active material layer forming composition, which is manufactured by dissolving or dispersing the positive electrode active material described above and optionally a binder, a conductive agent, and a dispersant in a solvent as needed, is applied onto a positive electrode current collector, followed by drying and rolling.

[0177] According to one embodiment of the present invention, the solvent may be a solvent generally used in the art, such as dimethylsulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, or water, and one of these may be used alone or as a mixture of two or more. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, binder, and dispersant in consideration of the coating thickness and manufacturing yield of the slurry, and to have a viscosity that can exhibit excellent thickness uniformity when applied thereafter for manufacturing the positive electrode.

[0178] Additionally, in another method, the positive electrode may be manufactured by casting the composition for forming the positive electrode active material layer on a separate support, and then laminating the resulting film on a positive electrode current collector by peeling it off from the support.

[0179]

[0180] Lithium secondary battery

[0181] The present invention provides a lithium secondary battery including the above positive electrode material.

[0182] The lithium secondary battery specifically includes a positive electrode, a negative electrode positioned opposite the positive electrode, and a separator and electrolyte interposed between the positive electrode and the negative electrode. Since the positive electrode is the same as described above, a detailed description thereof will be omitted, and only the remaining components will be specifically described below.

[0183] In addition, the lithium secondary battery may optionally further include a battery container that houses the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member that seals the battery container.

[0184] In the above lithium secondary battery, the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.

[0185] According to one embodiment of the present invention, the 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. In addition, the negative electrode current collector can typically have a thickness of 3 ㎛ to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it 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.

[0186] According to one embodiment of the present invention, the negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material.

[0187] According to one embodiment of the present invention, a compound capable of reversible intercalation and deintercalation of lithium may be used as the negative electrode active material. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; 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 metal oxides capable of doping and dedoping lithium; or composites containing the above metallic compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and 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 electrode active material. In addition, both low-crystalline carbon and high-crystalline carbon may be used as the carbonaceous material. Representative examples of low-crystalline carbon include soft carbon and hard carbon, and representative examples of high-crystalline carbon include natural graphite or artificial graphite in the form of amorphous, plate-like, flaky, spherical, or fibers, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes.

[0188] According to one embodiment of the present invention, the negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode active material layer.

[0189] According to one embodiment of the present invention, the binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0190] According to one embodiment of the present invention, the conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10 wt% or less, specifically 5 wt% or less, based on the total weight of the negative electrode active material layer. The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber or metal fiber; metal powders such as fluorocarbon, aluminum, and nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0191] According to one embodiment of the present invention, the negative electrode active material layer can be manufactured by applying and drying a composition for forming a negative electrode active material layer prepared by dissolving or dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent, on a negative electrode current collector, or by casting the composition for forming a negative electrode active material layer on a separate support, and then laminating the film obtained by peeling it off from the support on a negative electrode current collector.

[0192] Meanwhile, in the lithium secondary battery, the separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. Any separator commonly used in lithium secondary batteries can be used without any particular restrictions, and in particular, one having low resistance to ion movement of the electrolyte and excellent electrolyte moisture absorption capacity is preferable. Specifically, 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, may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. 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, and may optionally be used in a single-layer or multi-layer structure.

[0193] In addition, examples of the electrolyte include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0194] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0195] According to one embodiment of the present invention, the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R represents a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable.In this case, the performance of the electrolyte may be improved when the cyclic carbonate and the chain carbonate are mixed and used in a volume ratio of about 1:1 to about 1:9.

[0196] According to one embodiment of the present invention, 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 anion of the lithium salt may be at least one selected from the group consisting of F-, Cl-, Br-, I-, NO3-, N(CN)2-, BF4-, CF3CF2SO3-, (CF3SO2)2N-, FSO2)2N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3-, CF3CO2-, CH3CO2-, SCN-, and (CF3CF2SO2)2N-, and the lithium salt may be at least one selected from the group consisting of LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, or LiB(C2O4)2 can be used. It is recommended that the concentration of the lithium salt be within the range of 0.1 to 2.0 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.

[0197]

[0198] According to one embodiment of the present invention, in addition to the electrolyte components, the electrolyte may further include one or more additives, such as, for example, a haloalkylene carbonate compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, a cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 5 wt% based on the total weight of the electrolyte.

[0199] As described above, a lithium secondary battery including a cathode active material according to the present invention stably exhibits excellent discharge capacity, output characteristics, and lifespan characteristics, and is therefore useful in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0200] Accordingly, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same can be provided.

[0201] The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as power tools; electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or power storage systems.

[0202] There is no particular limitation on the external shape of the above lithium secondary battery, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape.

[0203] The above lithium secondary battery can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells.

[0204] Examples of the above medium and large devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems.

[0205]

[0206] Hereinafter, embodiments of the present invention will be described 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.

[0207]

[0208] Example 1

[0209] <Manufacturing of positive electrode active material precursor seed>

[0210] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 2.59 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 5 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously purging nitrogen gas into the reactor at a rate of 5 L / min, 14.4 mL of a 25 wt% NaOH aqueous solution and 130.1 mL of a 9 wt% NH4OH aqueous solution were added, and the mixture was stirred at a stirring speed of 850 rpm at 50°C to adjust the pH in the reactor to 12.5.

[0211] Afterwards, nitrogen gas was continuously purged into the reactor at a rate of 2 L / min, and while stirring at a stirring speed of 850 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 0.29 L / hr, the NaOH aqueous solution at 0.17 L / hr, and the NH4OH aqueous solution at 0.04 L / hr, and the co-precipitation reaction was performed at 50°C and pH 12.25 for 66 hours to generate and grow nuclei of positive electrode active material precursor particles. Then, after about 20 hours, when the reactor was full, the overflow pipe was opened to measure the average particle diameter (D 50 ) was secured as a seed solution containing a positive electrode active material precursor seed having a diameter of 1.3 μm. The secured positive electrode active material precursor seed is 9% of the theoretical yield of the positive electrode active material precursor produced when the reaction for manufacturing positive electrode active material precursor particles described below (hereinafter referred to as “finished product reaction”) is performed for 24 hours.

[0212] The above theoretical yield can be calculated using the following mathematical formula 3.

[0213] [Equation 3]

[0214] Theoretical yield of positive electrode active material precursor = hourly input flow rate of transition metal solution (L / hr) * reaction time (24 hr) * concentration of transition metal solution (mol / L) * molar mass of positive electrode active material precursor (g / mol)

[0215]

[0216] <Manufacturing of positive electrode active material precursor particles (finished product reaction)>

[0217] After purging the batch reactor with nitrogen to remove dissolved oxygen and create a non-oxidizing atmosphere, the seed solution was filled, the internal temperature of the batch reactor was maintained at 50°C, and the rotation speed was set to 800 rpm. Then, the seed solution was stirred in the batch reactor for 30 minutes.

[0218] Afterwards, NiSO4, CoSO4, and MnSO4 were mixed in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7, and a 2.4 M concentration transition metal solution was added at a rate of 0.96 ml / min, an ammonium ion-containing solution was added at a rate of 0.14 ml / min, and an alkaline aqueous solution was added at a rate such that the pH of the reaction solution was maintained at 11.4. At this time, the internal temperature of the batch reactor was maintained at 50°C, the rotation speed was reduced to 620 rpm, and the positive electrode active material precursor particles were grown for a total of 27 hours to manufacture positive electrode active material precursor particles.

[0219] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88 Co 0.05 Mn 0.07 It was (OH)2.

[0220]

[0221] Example 2

[0222] The positive electrode active material precursor particles were manufactured in the same manner as in Example 1, except that the obtained positive electrode active material precursor seed was 7% of the theoretical yield of the positive electrode active material precursor produced based on 24 hours of finished product reaction, and the positive electrode active material precursor particles were grown for a total of 26.5 hours to manufacture the positive electrode active material precursor particles.

[0223]

[0224] Example 3

[0225] <Manufacturing of positive electrode active material precursor seed>

[0226] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 2150 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 120 to 180 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously purging nitrogen gas into the reactor at a rate of 120 to 180 L / min, 1800 to 2000 g of a 25 wt% NaOH aqueous solution and 9300 to 9900 g of a 9 wt% NH4OH aqueous solution were added, and the mixture was stirred at a stirring speed of 220 rpm at 50°C to adjust the pH in the reactor to 12.5.

[0227] Afterwards, nitrogen gas was continuously purged into the reactor at a rate of 120 to 180 L / min, and while stirring at a stirring speed of 220 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 570 to 590 L / hr, the NaOH aqueous solution at a rate of 350 to 370 L / hr, and the NH4OH aqueous solution at a rate of 55 to 60 L / hr, and the coprecipitation reaction was performed at 50°C and pH 11.30 to 11.70 for 24 hours, thereby generating and growing the nuclei of the positive electrode active material precursor particles. At this time, the coprecipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter, and the average particle diameter (D 50 ) was secured as a seed solution containing a positive electrode active material precursor seed having a diameter of 3.1 μm. The yield of the positive electrode active material precursor produced when the positive electrode active material precursor seed finished product reaction was performed for 48 hours is 4% of the theoretical yield of the positive electrode active material precursor.

[0228] The above theoretical yield can be calculated using the following mathematical formula 3.

[0229] [Equation 3]

[0230] Theoretical yield of positive electrode active material precursor = hourly input flow rate of transition metal solution (L / hr) * reaction time (24 hr) * concentration of transition metal solution (mol / L) * molar mass of positive electrode active material precursor (g / mol)

[0231]

[0232] <Manufacturing of positive electrode active material precursor particles (finished product reaction)>

[0233] After purging the batch reactor with nitrogen to remove dissolved oxygen and create a non-oxidizing atmosphere, the seed solution and 12900 L of deionized water were filled, the internal temperature of the batch reactor was maintained at 50°C, and 4000 to 4100 g of a 25 wt% NaOH aqueous solution and 387000 to 397000 g of a 9 wt% NH4OH aqueous solution were added, and stirring was performed at a stirring speed of 50 rpm at 50°C to adjust the pH inside the reactor to 11.5.

[0234] Afterwards, NiSO4, CoSO4, and MnSO4 were mixed in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7, and a 2.4 M concentration transition metal solution was added at a rate of 2500 L / min, an ammonium ion-containing solution was added at a rate of 370 to 380 L / min, and an alkaline aqueous solution was added at a rate such that the pH of the reaction solution was maintained at 11.3 to 11.8. At this time, the internal temperature of the batch reactor was maintained at 50℃, and the rotation speed was reduced to 30 rpm. The positive electrode active material precursor particles were grown for a total of 48 hours to manufacture the positive electrode active material precursor particles. At this time, the coprecipitation reaction was performed by discharging the reaction solution other than the precursor particles present inside using a filter.

[0235] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88 Co 0.05 Mn 0.07 It was (OH)2.

[0236]

[0237] Comparative Example 1

[0238] The positive electrode active material precursor particles were manufactured in the same manner as in Example 1, except that the obtained positive electrode active material precursor seed was 12% of the theoretical yield of the positive electrode active material precursor produced based on 24 hours of finished product reaction, and the positive electrode active material precursor particles were grown for a total of 30 hours to manufacture the positive electrode active material precursor particles.

[0239]

[0240] Comparative Example 2

[0241] The positive electrode active material precursor particles were manufactured in the same manner as in Example 1, except that the obtained positive electrode active material precursor seed was 14% of the theoretical yield of the positive electrode active material precursor produced based on 24 hours of finished product reaction, and the positive electrode active material precursor particles were grown for a total of 34.5 hours to manufacture the positive electrode active material precursor particles.

[0242]

[0243] Comparative Example 3

[0244] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 28.5 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 8 to 10 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously supplying nitrogen gas to the reactor at a rate of 8 to 10 L / min, 210 to 220 g of a 25 wt% NaOH aqueous solution and 1220 to 1230 g of a 9 wt% NH4OH aqueous solution were added, and the pH inside the reactor was adjusted to 12.4 by stirring at a stirring speed of 300 rpm at 50°C. At this time, a co-precipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter.

[0245] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 8 to 10 L / min, and while stirring at a stirring speed of 600 rpm gradually reduced to 360 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 7.75 L / hr, the NaOH aqueous solution at a rate of 0.73 L / hr, and the NH4OH aqueous solution at a rate of 4.5 to 4.8 L / hr, and the temperature was lowered from 50°C to pH 12.4 to 11.4 for 16 to 20 hours. The pH was then maintained for 24 hours of reaction to generate and grow positive electrode active material precursor particles.

[0246] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88 Co 0.05 Mn0.07 It was (OH)2.

[0247]

[0248] Comparative Example 4

[0249] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 28.5 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 8 to 10 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously supplying nitrogen gas to the reactor at a rate of 8 to 10 L / min, 210 to 220 g of a 25 wt% NaOH aqueous solution and 1220 to 1230 g of a 9 wt% NH4OH aqueous solution were added, and the pH inside the reactor was adjusted to 12.4 by stirring at a stirring speed of 300 rpm at 50°C. At this time, a co-precipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter.

[0250] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 8 to 10 L / min, and while stirring at a stirring speed of 600 rpm gradually reduced to 300 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 7.87 L / hr, the NaOH aqueous solution at a rate of 0.73 L / hr, and the NH4OH aqueous solution at a rate of 4.5 to 4.8 L / hr, and the temperature was lowered from 50°C to pH 12.4 to 11.1 for 16 to 20 hours. The pH was then maintained for 26 hours of reaction to generate and grow positive electrode active material precursor particles.

[0251] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88Co 0.05 Mn 0.07 It was (OH)2.

[0252]

[0253] Comparative Example 5

[0254] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in amounts such that the molar ratio of nickel:cobalt:manganese was 89:4:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 4 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 4 to 6 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously supplying nitrogen gas to the reactor at a rate of 4 to 6 L / min, 30 to 35 g of a 25 wt% NaOH aqueous solution and 150 to 155 g of a 9 wt% NH4OH aqueous solution were added, and the mixture was stirred at a stirring speed of 300 rpm at 50°C to adjust the pH in the reactor to 12.5.

[0255] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 4 to 6 L / min, and while stirring at a stirring speed gradually reduced from 900 rpm to 500 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 0.96 L / hr, the NaOH aqueous solution at 0.13 L / hr, and the NH4OH aqueous solution at a rate of 0.56 to 0.58 L / hr, and the temperature was lowered from 50°C to pH 12.5 to 11.8 for 6 to 10 hours. The pH was then maintained for 68 hours of reaction to generate and grow positive electrode active material precursor particles. At this time, the co-precipitation reaction was performed by discharging the reaction solution other than the precursor particles present inside using a filter.

[0256] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles.0.89 Co 0.04 Mn 0.07 It was (OH)2.

[0257]

[0258] Comparative Example 6

[0259] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 60:10:30. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 2.9 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 4 to 6 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while continuously introducing nitrogen gas into the reactor at a rate of 4 to 6 L / min, 20 to 26 g of a 25 wt% NaOH aqueous solution and 110 to 120 g of a 9 wt% NH4OH aqueous solution were introduced, and the pH inside the reactor was adjusted to 12.5 by stirring at a stirring speed of 300 rpm at 50°C. At this time, a co-precipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter.

[0260] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 4 to 6 L / min, and while stirring at a stirring speed of 1000 rpm gradually reduced to 400 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 0.77 L / hr, the NaOH aqueous solution at a rate of 0.46 L / hr, and the NH4OH aqueous solution at a rate of 0.10 to 0.11 L / hr, and the temperature was lowered from 50°C to pH 12.5 to 11.9 for 18 to 22 hours. The pH was then maintained for 30 hours of reaction to generate and grow positive electrode active material precursor particles.

[0261] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.60 Co 0.10 Mn 0.30 It was (OH)2.

[0262]

[0263] Comparative Example 7

[0264] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 2250 L of deionized water was added to the reactor, and nitrogen gas was purged into the reactor at a rate of 190 to 210 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while nitrogen gas was continuously fed into the reactor at a rate of 190 to 210 L / min, 16,000 to 16,400 g of a 25 wt% NaOH aqueous solution and 94,300 to 94,700 g of a 9 wt% NH4OH aqueous solution were fed, and the pH inside the reactor was adjusted to 12.7 by stirring at a stirring speed of 150 rpm at 50°C. At this time, the co-precipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter.

[0265] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 190 to 210 L / min, and while stirring at a stirring speed of 220 rpm gradually reduced to 76 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 588 L / hr, the NaOH aqueous solution at a rate of 353 L / hr, and the NH4OH aqueous solution at a rate of 56 to 60 L / hr, and the temperature was lowered from 50°C to pH 12.4 to 11.4 for 6 to 10 hours. Thereafter, the pH was maintained for 20 hours of reaction, thereby generating and growing positive electrode active material precursor particles.

[0266] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88 Co 0.05 Mn 0.07 It was (OH)2.

[0267]

[0268] Comparative Example 8

[0269] A 2.4 M transition metal solution was prepared by mixing NiSO4, CoSO4, and MnSO4 in deionized water in an amount such that the molar ratio of nickel:cobalt:manganese was 88:5:7. A container containing the transition metal solution, a container containing a 25 wt% concentration NaOH aqueous solution, and a container containing a 9 wt% concentration NH4OH aqueous solution were each connected to a continuous stirred tank reactor. Subsequently, 2550 to 2650 L of deionized water was added to the reactor, and nitrogen gas was introduced into the reactor at a rate of 3000 to 3300 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere inside the reactor. Afterwards, while nitrogen gas was continuously fed into the reactor at a rate of 3000 to 3300 L / min, 16200 to 16400 g of a 25 wt% NaOH aqueous solution and 94500 to 94700 g of a 9 wt% NH4OH aqueous solution were fed, and the pH inside the reactor was adjusted to 12.0 by stirring at a stirring speed of 900 rpm at 33 to 42°C. At this time, the co-precipitation reaction was performed while discharging the reaction solution other than the precursor particles present inside using a filter.

[0270] Thereafter, nitrogen gas was continuously purged into the reactor at a rate of 900 to 1100 L / min, and while stirring at a stirring speed of 2220 rpm gradually reduced to 900 rpm, the transition metal solution was continuously introduced into the reactor at a rate of 800 to 850 L / hr, the NaOH aqueous solution at a rate of 430 to 470 L / hr, and the NH4OH aqueous solution at a rate of 80 to 95 L / hr, and the temperature was lowered from 33 to 42°C and the pH from 12.0 to 12.2 to 10.5 to 10.7 for 2 to 4 hours. Afterwards, the pH was raised to 11.4 to 11.6 and maintained for 60 hours of reaction, thereby generating and growing positive electrode active material precursor particles.

[0271] The manufactured precursor particles were filtered through a vacuum filter and dried at 110°C for 15 hours to obtain the composition of the positive electrode active material precursor particles. 0.88 Co 0.05 Mn 0.07 It was (OH)2.

[0272]

[0273] Experimental Example 1: Analysis of the positive electrode active material precursor

[0274] * Evaluation of particle size and particle size distribution: The particle size of each of the positive electrode active material precursors manufactured in Examples 1 to 3 and Comparative Examples 1 to 8 was measured (based on a refractive index of 1.55) using a particle size distribution measuring device (S-3500, Microtrac Co.), and the results are shown in Table 1 below.

[0275]

[0276] * Tap density evaluation: 50 g of the positive electrode active material precursors prepared in Examples 1 to 3 and Comparative Examples 1 to 8 were each charged into a 100 mL container, and the apparent density of the resulting particles was measured by vibrating them 3,000 times with a 40 mm torque. Specifically, the tap density of the positive electrode active material precursors was measured using a tap density tester (KYT-4000, Seishin). The measurement results are shown in Table 1 below.

[0277]

[0278] * Sphericity evaluation: The sphericity of the positive electrode active material precursors manufactured in Examples 1 to 3 and Comparative Examples 1 to 8 was confirmed using a scanning electron microscope (SEM). The sphericity value of each positive electrode active material precursor particle in each SEM image was measured using the following mathematical formula 1, and then the average value was calculated, which is shown as the average sphericity value in Table 1 below.

[0279] [Mathematical Formula 1]

[0280]

[0281] In the above mathematical formula 1,

[0282] A is the area on the plane shown in the SEM image of the particle measured by shape analysis of the SEM image,

[0283] P is the perimeter on the plane shown in the SEM image of the particle measured by shape analysis of the SEM image.

[0284]

[0285] * Multi-particle ratio: Figures 1 to 5 are SEM images (2k) showing the positive electrode active material precursors manufactured in Examples 1 to 3 and Comparative Examples 1 and 2, respectively. In each SEM image, the aspect ratio value, which is the ratio of the major axis length to the minor axis length on a plane shown in the SEM image of each positive electrode active material precursor particle, was obtained, and the ratio of particles having an aspect ratio value less than 1.4 was obtained to obtain the multi-particle ratio.

[0286] Example Comparative Example 1 2 3 1 2 3 4 5 6 7 8 Particle size (㎛) D 5 0 4.3 4.3 9.8 5 4.2 4.2 3.1 4 3.0 15.0 15.9 3.1 3 10.0 1 D 5 2.9 2.9 7.5 9 2.9 2.7 0.3 9 0.3 4 0.7 10.9 6 0.9 9 7.6 2 D 9 5 6.3 6.2 13.9 4.5 6.5 6.5 4.7 9 4.5 6.8 8 10.9 4.8 3 14.2 2 D m in0.30.36.000.30.60.20.210.320.410.366.00Dmax9.29.322.0011117.787.78.3614.55.9222.00SpanValue0.790.770.640.830.911.41.171.230.491.230.66Tab Density (g / ml) 1.97 1.92 1.96 1.89 1.84 1.71 1.65 Unanalyzed Unanalyzed 1.65 1.96 Sphericity Mean value 0.79 10.81 80.89 30.74 30.71 90.83 0.79 0.82 0.59 0.80 87 2 Multiparticle ratio (%) 5.6 5.6 3.83 07.93 3.5 3.9 14.5 5 2.74 4 1.91 8.4 5 6.670

[0287] Referring to Table 1 above, it was confirmed that the positive electrode active material precursors according to Examples 1 to 3, in which the content of the positive electrode active material precursor seed introduced into the batch reactor was at an appropriate level, exhibited excellent span values, sphericity, and multi-particle ratios. In the case of the positive electrode active material precursors according to Comparative Examples 1 and 2, in which the content of the positive electrode active material precursor seed introduced into the batch reactor was greater than the appropriate amount, it was confirmed that the multi-particle ratio was significantly increased compared to Examples 1 to 3.

[0288] For Comparative Examples 3 to 8 manufactured by a manufacturing method that did not perform the step (S1) of manufacturing a seed solution, the following applies.

[0289] It was confirmed that the positive electrode active material precursors according to Comparative Examples 3 to 5 had higher span values ​​compared to Examples 1 to 3. In addition, it was confirmed that the positive electrode active material precursor according to Comparative Example 6 had a significantly increased multi-particle ratio and poor sphericity compared to Examples 1 to 3. In addition, it was confirmed that the positive electrode active material precursor according to Comparative Example 7 had a higher span value and increased multi-particle ratio compared to Examples 1 to 3. The positive electrode active material precursor according to Comparative Example 8 had a high multi-particle ratio.

[0290] Through the above comparative examples, it was confirmed that there is a limit to significantly improving the span value, sphericity, and multi-particle ratio when step (S1) is not performed during the manufacture of the positive electrode active material precursor.

[0291]

[0292] Experimental Example 2: Determining Residual Lithium Amount

[0293] The positive electrode active material precursors manufactured in the above examples and comparative examples and the lithium source were placed in a Henschel mixer (700 L) so that the molar ratio (Li / M) of lithium (Li) in the lithium source LiOH to the total metal elements (M) was 1.030, and mixed at 300 rpm in the center for 20 minutes. The mixed powder was placed in an alumina crucible, heated at 5°C / min, and calcined at 800-900°C for 10 hours in an atmosphere with an oxygen concentration of 85-95% to manufacture a lithium transition metal oxide.

[0294] 5 g of the above lithium transition metal oxide was added to 100 g of distilled water, mixed for 5 minutes, and then filtered. After filtering, the amounts of Li2CO3 and LiOH dissolved in the distilled water were measured using a pH meter by titration (using 0.1 N HCl).

[0295] Li2CO3(wt%)LiOH(wt%)Example 30.2150.403Comparative example 90.3980.390

[0296] As shown in Table 2 above, it can be confirmed that the value of Li2CO3 was reduced by approximately 45% in Example 3 compared to Comparative Example 9. This means that the formation of a layered structure of the positive electrode active material and the smooth insertion of the Li source into the layered structure were achieved through uniform heat treatment, and additionally, the reduction in Li2CO3 resulted in a reduction in the generation of gases that cause insulation and swelling during charge and discharge.

[0297]

[0298] Experimental Example 3: Battery Performance Evaluation

[0299] Each of the positive electrode active materials, carbon black conductive agent, and polyvinylidene fluoride (PVDF) binder manufactured in Examples and Comparative Examples was mixed in a ratio of 96:2:2 in an N-methylpyrrolidone (NMP) solvent to manufacture a positive electrode slurry. The positive electrode slurry was applied to one surface of an aluminum current collector, dried at 150°C, and rolled to manufacture a positive electrode.

[0300] A lithium metal electrode was used as the negative electrode, and a porous polyethylene separator was interposed between the positive and negative electrodes to manufacture an electrode assembly. The electrode assembly was then placed inside a battery case, and an electrolyte was injected into the case to manufacture a half-cell. At this time, the electrolyte was prepared by dissolving 0.7 M LiPF6 in an organic solvent containing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0301] For each half-cell manufactured in this way, the initial charge capacity and initial discharge capacity were measured and the initial efficiency was calculated while charging at 0.5C to 4.2V in CC-CV mode at 25℃ and discharging at a constant current of 1C to 3.0V. For reference, the initial efficiency value is the percentage value of the initial discharge capacity to the initial charge capacity.

[0302] Initial charge capacity (mAh / g) Initial discharge capacity (mAh / g) Initial efficiency (%) Example 3 232.09 212.209 1.43 Comparative example 9 227.86 203.808 9.44

[0303] As shown in Table 3 above, it can be confirmed that the initial charge / discharge capacity and efficiency of a lithium secondary battery are improved when the positive electrode active material precursor according to the present invention is used.

Claims

1. The average value of the sphericity according to the following mathematical formula 1 is 0.73 or more and 1.0 or less, The span value according to the following mathematical formula 4 is 0.4 or more and 0.9 or less, A cathode active material precursor having a ratio of multi-particles of less than 6%, wherein the aspect ratio value obtained by shape analysis of a SEM image is less than 1.4: [Mathematical Formula 1] In the above mathematical expression 1, A is the area of the particle measured by shape analysis of the SEM image, P is the perimeter of the particle measured by morphological analysis of the SEM image. [Mathematical Formula 4] Span = (D 95 - D5) / D 50 2. In paragraph 1, A cathode active material precursor having a span value of 0.60 or more and 0.85 or less according to the above mathematical expression 1.

3. In paragraph 1, A cathode active material precursor having a multi-particle ratio of 4% or less.

4. In paragraph 1, A cathode active material precursor having an average value of the above sphericity of 0.75 or more and 0.90 or less.

5. In paragraph 1, Average particle diameter (D) 50 ) is a positive electrode active material precursor having a particle size of 2 ㎛ or more and 11 ㎛ or less.

6. Step (S1) of producing a seed solution containing a positive electrode active material precursor seed by continuously introducing and mixing a transition metal-containing solution, an ammonium cation complex forming agent, and an alkaline aqueous solution into a continuous stirred tank reactor (CSTR); and It includes a step (S2) of introducing the seed solution manufactured in the above step (S1) into a batch reactor, stirring it, and then introducing a solution containing a transition metal, an ammonium cation complex forming agent, and an alkaline aqueous solution to grow positive electrode active material precursor particles. A method for producing a cathode active material precursor, wherein the content of the cathode active material precursor seed included in the seed solution fed into the batch reactor in the step (S2) above is 4% or more and 11% or less of the theoretical yield of the cathode active material precursor finally produced.

7. In paragraph 6, A method for producing a cathode active material precursor, wherein the content of the cathode active material precursor seed included in the seed solution fed into the batch reactor in the step (S2) above is 4% or more and 9% or less of the theoretical yield of the cathode active material precursor finally produced.

8. In paragraph 6, A method for producing a positive electrode active material precursor, wherein the concentration of an ammonium cation complex forming agent in the reactants and the pH of the reactants in the step (S2) are controlled in the same manner as in the step (S1).

9. A cathode active material which is a sintered product of a mixture comprising a cathode active material precursor according to claim 1 and a lithium raw material.

10. A lithium secondary battery comprising a positive electrode active material according to claim 9.

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