Precursor for positive electrode active material and preparation method therefor

Abstract

The present invention relates to a precursor for a positive electrode active material and a preparation method therefor, wherein the precursor comprises a transition metal hydroxide having a nickel content of 50 mol% or more among all metals, and has a span value of 0.8 or less as defined by formula (1) and an FPS value of 0.2 or more as defined formula (2). Formula (1): Span = (D90 - D10) / D50 In formula (1), D10, D50, and D90 are particle diameters when cumulative volumes are 10 vol%, 50 vol%, and 90 vol%, respectively, in a volume cumulative particle size distribution of the precursor for a positive electrode active material. Formula (2): FPS = S / (D50)0.5 In formula (2), S is a sphericity of the precursor for a positive electrode active material, and D50 is a particle diameter when a cumulative volume is 50 vol% in a volume cumulative particle size distribution of the precursor for a positive electrode active material.

Description

Precursor for positive electrode active material and method for manufacturing the same

[0001] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0199362 filed on December 27, 2024 and Korean Patent Application No. 10-2025-0208536 filed on December 23, 2025, and all contents disclosed in said Korean patent application documents are incorporated herein as part of the specification.

[0002] The present invention relates to a precursor for an anode active material and a method for manufacturing the same, and more specifically, to a precursor for an anode active material having excellent particle uniformity and sphericity and a method for manufacturing the same.

[0003] Recently, the demand for lithium-ion batteries as an energy source for mobile devices, electric vehicles, and the like has been surging.

[0004] A lithium secondary battery is generally manufactured by forming an electrode assembly by interposing a separator between a positive electrode containing a positive active material composed of a transition metal oxide containing lithium and a negative electrode containing a negative active material capable of storing lithium ions, inserting the electrode assembly into a battery case, injecting a non-aqueous electrolyte that serves as a medium for transmitting lithium ions, and then sealing it.

[0005] Lithium transition metal composite oxides are used as cathode active materials for lithium secondary batteries, and among these, nickel-based lithium composite transition metal oxides are widely used due to their excellent capacity and lifespan characteristics. Nickel-based lithium composite transition metal oxides are primarily manufactured by preparing a hydroxide precursor through a co-precipitation reaction of an aqueous transition metal solution, and then mixing the said precursor with a lithium source material and calcining the mixture.

[0006] Conventionally, it was common practice to perform the co-precipitation reaction for precursor production in a nitrogen atmosphere. However, when the co-precipitation reaction is performed in a nitrogen atmosphere, it is difficult to control the growth reaction rate, resulting in a wide particle size distribution and reduced sphericity of the precursor. This problem is particularly pronounced in the case of small particle precursors with a particle size of 5㎛ or less.

[0007] Since the particle size and shape of the positive electrode active material are influenced by the particle size and shape of the precursor, if the particle size distribution of the precursor is wide and the sphericity is low, the particle size and sphericity of the finally manufactured positive electrode active material also decrease, leading to problems such as deterioration of electrochemical properties and processability.

[0008] Therefore, there is a need to develop precursors with excellent particle size uniformity and sphericity.

[0009] The present invention aims to solve the above-mentioned problems by providing a precursor with excellent particle size uniformity and sphericity, and a method for manufacturing such a precursor.

[0010] In addition, the present invention aims to provide a positive electrode active material manufactured using the above-described precursor, and a positive electrode and a lithium secondary battery comprising the same.

[0011] [1] The present invention comprises a transition metal hydroxide having a nickel content of 50 mol% or more of the total metal, a span value of 0.8 or less as defined by the following formula (1), and F as defined by the following formula (2). PS A precursor for a positive electrode active material having a value of 0.2 or higher is provided.

[0012] Equation (1): Span = (D 90 - D 10 ) / D 50

[0013] In the above equation (1), D 10 , D 50 and D 90These are the particle sizes when the cumulative volume is 10 vol%, 50 vol%, and 90 vol%, respectively, in the volume cumulative particle size distribution of the precursor for the positive electrode active material.

[0014] Equation (2): F PS = S / (D 50 ) 0.5

[0015] In the above equation (2), S is the degree of sphericity of the precursor for the positive active material, and D 50 is the particle size when the cumulative volume is 50 vol% in the volume cumulative particle size distribution of the above-mentioned precursor for the positive active material.

[0016] [2] The present invention provides a precursor for an anode active material, wherein, in [1], the transition metal hydroxide has a composition represented by the following [Chemical Formula 1].

[0017] [Chemical Formula 1]

[0018] Ni a Co b M 1 c M 2 d (OH)2

[0019] In the above [Chemical Formula 1], M 1 is Mn, Al, or a combination thereof, and M 2 ... comprises one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, Sr, and Nb, and 0.5≤a<1, 0 <b<0.5, 0<c<0.5, 0≤d≤0.2이다.

[0020] [3] The present invention provides a precursor for an anode active material, wherein, in [1] or [2], the transition metal hydroxide is in the form of a secondary particle formed by the aggregation of a plurality of primary particles, and the average particle size of the primary particles is 0.1 to 1.2 μm.

[0021] [4] The present invention is, in at least one of [1] to [3] above, the D 50This provides a precursor for a positive electrode active material having a thickness of 2㎛ to 17㎛.

[0022] [5] The present invention provides a precursor for an anode active material in which, in at least one of [1] to [4], S is 0.65 or higher.

[0023] [6] The present invention, in at least one of [1] to [5], has a BET specific surface area of ​​10 m 2 / g to 30 m 2 Provides a precursor for a positive electrode active material with a g / g content.

[0024] [7] The present invention, in at least one of [1] to [6], has a tap density of 0.8 g / cm³ 3 Up to 2.5 g / cm² 3 Provides a precursor for a positive electrode active material.

[0025] [8] The present invention provides a method for manufacturing a precursor for an anode active material, comprising: a seed formation step of forming a reaction solution containing a precursor seed by supplying and reacting a metal solution containing 50 mol% or more of nickel among the total metals, an ammonium cation complex forming agent, and a basic solution; and a particle growth step of growing precursor particles by stirring while supplying the metal solution, the ammonium cation complex forming agent, and the basic solution to the reaction solution containing the precursor seed, wherein at least one of the steps of preparing the reaction mother liquor, the seed formation step, and the particle growth step is performed in an oxidizing atmosphere, and the supply flow rate of the metal solution in the seed formation step is 0.4 to 0.7 times the supply flow rate of the metal solution in the particle growth step.

[0026] [9] The present invention provides a method for manufacturing a precursor for an anode active material, wherein, in the above [8], at least one step of the seed formation step and the particle growth step involves introducing a gas containing oxygen.

[0027]

[0010] The present invention provides a method for manufacturing a precursor for an anode active material, wherein, in [8] or [9], the oxygen-containing gas is introduced in an amount such that the amount of oxygen per 1 kg of transition metal in the metal solution is 20 L to 60 L.

[0028]

[0011] The present invention provides a method for manufacturing a precursor for an anode active material, wherein, in at least one of [8] to

[0010] , the reaction time of the seed formation step is 0.03 to 0.2 times the reaction time of the particle growth step.

[0029]

[0012] The present invention provides a positive active material which is a calcined product of a mixture of a positive active material precursor of any one of [1] to [7] and a lithium raw material.

[0030]

[0013] The present invention provides a positive active material, wherein, in

[0012] , the positive active material has a composition represented by the following [Chemical Formula 2].

[0031] [Chemical Formula 2]

[0032] Li 1+x [Ni a1 Co b1 M 1 c1 M 2 d1 ]O2

[0033] In the above [Chemical Formula 2], M 1 is Mn, Al, or a combination thereof, and M 2 ... comprises one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, Sr, and Nb, and -0.2≤x≤0.2, 0.5≤a1<1, 0 <b1<0.5, 0<c1<0.5, 0≤d1≤0.2임.

[0034]

[0014] The present invention provides a positive electrode comprising the positive electrode active material of

[0012] or

[0013] .

[0035]

[0015] The present invention provides a lithium secondary battery comprising the positive electrode, negative electrode, and electrolyte of

[0014] .

[0036] The method for manufacturing a precursor for an anode active material according to the present invention enables the production of a precursor with high particle size uniformity and sphericity by carrying out a co-precipitation reaction in an oxidizing atmosphere and controlling the growth rate of the precursor particles to a low level by adjusting the flow rate of the metal solution during the seed formation step and the particle growth step.

[0037] Since the precursor for a positive electrode active material according to the present invention has higher particle size uniformity and sphericity compared to conventional precursors, when a positive electrode active material is manufactured using this precursor, the particle size uniformity and sphericity of the positive electrode active material are also high. High sphericity of the positive electrode active material reduces the occurrence of cycle cracks during charging and discharging, thereby improving lifespan characteristics. Furthermore, high particle size uniformity of the positive electrode active material can result in improved initial resistance.

[0038] In addition, when a single-particle type cathode active material is manufactured using the precursor according to the present invention, the occurrence of defects within the cathode crystal structure due to over-sintering is mitigated, thereby improving initial resistance, and the fine particle content is reduced due to uniform grain growth during sintering, thereby improving lifespan and reducing gas.

[0039] Figure 1 is a scanning electron microscope image of the precursor powder of Example 1.

[0040] Figure 2 is a scanning electron microscope image of the precursor powder of Comparative Example 1.

[0041] Figure 3 is a scanning electron microscope image of the precursor powder of Comparative Example 2.

[0042] In the present invention, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0043] In the present invention, "primary particle" refers to a particle in which no grain boundaries appear when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope.

[0044] In the present invention, "secondary particles" are particles formed by assembling primary particles.

[0045] In the present invention, "D 10 , D 50 and D 90 Each refers to the particle size corresponding to 10 vol%, 50 vol%, and 90 vol% of the volume cumulative particle size distribution of the powder to be measured, and can be measured using the laser diffraction method. For example, the powder to be measured can be measured by dispersing it in a dispersion medium, introducing it into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiating it with ultrasound of about 28 kHz at an output of 60 W, obtaining a volume cumulative particle size distribution graph, and then determining the particle size corresponding to 10 vol%, 50 vol%, and 90 vol% of the volume cumulative amount.

[0046] In the present invention, “sphericity” refers to the value obtained by dividing the circumference of a circle having the same area as the image of the particle being measured by the perimeter of the projected image, and can be measured using a Malvern shape / particle size analyzer.

[0047] In the present invention, the "specific surface area" is measured by the BET method, and specifically, can be calculated from the amount of nitrogen gas adsorbed at a liquid nitrogen temperature (77K) using BELSORP-mino II of BEL Japan.

[0048]

[0049] The present invention will be described in detail below.

[0050] The precursor for a positive electrode active material, the method for manufacturing the same, the positive electrode active material, and the positive electrode and / or lithium secondary battery according to the present invention comprise at least one of the configurations disclosed below, and may comprise any combination of technically feasible configurations among the configurations below.

[0051]

[0052] Method for manufacturing a precursor for a positive electrode active material

[0053] First, a method for manufacturing a precursor for an anode active material according to the present invention will be described.

[0054] A method for manufacturing a precursor for a positive electrode active material according to the present invention comprises (1) a seed formation step and (2) a particle growth step, wherein the seed formation step and / or the particle growth step are performed in an oxidizing atmosphere, and the supply flow rate of the metal solution in the seed formation step is 0.4 to 0.7 times, preferably 0.5 to 0.6 times, the supply flow rate of the metal solution in the particle growth step.

[0055] Conventionally, when manufacturing precursors for cathode active materials, it was common practice to perform the co-precipitation reaction in an inert atmosphere, such as a nitrogen atmosphere. However, performing the co-precipitation reaction in an inert atmosphere resulted in a problem where the particle growth rate was rapid, leading to reduced particle size uniformity and sphericity. To solve this problem, the present invention enables the production of a precursor with uniform particle size and high sphericity by performing the co-precipitation reaction in an oxidizing atmosphere to reduce the particle growth rate.

[0056] At this time, the oxidizing atmosphere can be formed by introducing an oxygen-containing gas during the seed formation step and / or particle growth step, or by introducing an oxidizing agent such as hydrogen peroxide into the reaction solution. Among these, introducing an oxygen-containing gas during at least one of the seed formation step and the particle growth step is more preferable in terms of controlling the pH of the reaction solution.

[0057] The above oxygen-containing gas may be a gas with an oxygen content of 21% or more, such as the atmosphere, for example, and preferably a gas with an oxygen content of 25% or more.

[0058] The oxygen-containing gas can be introduced in an amount such that the amount of oxygen per 1 kg of transition metal in the metal solution is 20 L to 60 L, preferably 30 L to 50 L, preferably 35 L to 45 L. When the amount of oxygen-containing gas introduced satisfies the above range, the specific surface area, primary particle size, and degree of sphericity of the precursor can be appropriately formed.

[0059] Meanwhile, in the present invention, the supply flow rate of the metal solution in the seed formation step is 0.4 to 0.7 times, preferably 0.5 to 0.6 times, the supply flow rate of the metal solution in the particle growth step. When the supply flow rates of the metal solution in the seed formation step and the particle growth step satisfy the above ratio, the particle growth rate is controlled, and a precursor with high particle size uniformity and sphericity can be obtained. If the flow rate of the metal solution in the seed formation step is too small compared to the flow rate of the metal solution in the particle growth step, the seeds are not sufficiently formed, resulting in reduced productivity and non-uniform particle size distribution; if it is too large, the particle size becomes non-uniform from the seed stage, and problems may arise such as reduced particle size uniformity even after growth is completed.

[0060] In addition, the reaction time of the seed formation step may be 0.03 to 0.2 times, preferably 0.05 to 0.1 times, and more preferably 0.06 to 0.08 times the reaction time of the particle growth step. If the reaction time of the seed formation step is too short compared to the reaction time of the particle growth step, seeds are not sufficiently formed, resulting in reduced productivity and non-uniform particle size distribution; if it is too long, the seed size becomes large, and the reaction speed in the growth step becomes too short, which may lead to problems such as non-uniform particle size distribution.

[0061]

[0062] Hereinafter, each step of the precursor manufacturing method of the present invention will be explained in more detail.

[0063]

[0064] (1) Seed formation stage

[0065] First, a metal solution containing 50 mol% or more of nickel among the total metals, an ammonium cation complex forming agent, and a basic solution are supplied and reacted to form a precursor seed in the reaction solution.

[0066] The above metal solution contains at least 50 mol% of nickel (Ni) among the total metals, and optionally Co element, M 1 Elements and / or M 2 It may contain elements. Here, M 1 can be Mn, Al, or a combination thereof, and M 2 It may include one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb.

[0067] The above metal solution comprises a nickel-containing raw material, optionally a cobalt-containing raw material, M 1 Containing raw materials and / or M 2 It is prepared by adding a containing raw material to a solvent, specifically water, or a mixed solvent of an organic solvent that can be uniformly mixed with water (e.g., alcohol, etc.), or an aqueous solution of a nickel-containing raw material, an aqueous solution of a cobalt-containing raw material, M 1 Aqueous solution of the contained raw material, M 2 It may be manufactured by mixing aqueous solutions of the contained raw materials. In this case, the nickel-containing raw material, the cobalt-containing raw material, M 1 Containing raw materials and M 2 The contained raw materials are the molar ratio of each element within the precursor, namely nickel, cobalt, M 1 , M 2It can be mixed in a stoichiometric ratio that satisfies the molar ratio of 1 Containing raw materials and M 2 The contained raw materials are nickel, cobalt, and M 1 , M 2 The molar ratio of can be mixed in an amount such that it satisfies the mole fractions of a, b, c, and d in the above [Chemical Formula 1].

[0068] The above nickel-containing raw material may be, for example, nickel-containing acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide, and specifically, may be Ni(OH)2, NiO, NiOOH, NiCO3, 2Ni(OH)2ㆍ4H2O, NiC2O2ㆍ2H2O, Ni(NO3)2ㆍ6H2O, NiSO4, NiSO4ㆍ6H2O, nickel fatty acid salts, nickel halides, or combinations thereof, but are not limited thereto.

[0069] The above cobalt-containing raw material may be a cobalt-containing acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide, and specifically may be Co(OH)2, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O, Co(SO4)2ㆍ7H2O or a combination thereof, but is not limited thereto.

[0070] The above M 1 In the contained raw material, M 1 It may be one or more of aluminum and manganese, and the above M 1 The contained raw material is M 1 It may be an acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide containing an element, etc. Specifically, the above M 1The contained raw materials may be manganese oxides such as Mn2O3, MnO2, Mn3O4, etc.; manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylate, manganese citrate, manganese fatty acid, manganese oxyhydroxide, manganese chloride; Al2O3, AlSO4, AlCl3, Al-isopropoxide, AlNO3, or combinations thereof, but are not limited thereto.

[0071] The above M 2 In the contained raw material, M 2 The element may include one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb, and M 2 The contained raw material is the above M 2 It may be an acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide containing the element.

[0072] Meanwhile, the ammonium cation complex-forming agent may be, for example, NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, NH4CO3, or a combination thereof, but is not limited thereto. Meanwhile, the ammonium-containing complex-forming agent may be used in the form of an aqueous solution, and in this case, water or a mixture of water and an organic solvent that is uniformly miscible with water (specifically, alcohol, etc.) may be used as the solvent.

[0073]

[0074] In the seed formation step, the pH of the reaction solution may be 8 to 13, preferably 10 to 13, and more preferably 11 to 13. When the pH of the reaction solution in the seed formation step satisfies the above range, seeds can be smoothly produced.

[0075] The seed formation step can be performed at a temperature of 50°C to 70°C, preferably 55°C to 70°C, more preferably 60°C to 70°C.

[0076] The seed formation reaction can be carried out for 1 to 8 hours, preferably 3 to 6 hours, more preferably 4 to 6 hours. If the seed formation reaction time is too short or too long, the particle size of the precursor particles may become non-uniform.

[0077] The seed formation reaction can be carried out while stirring the reaction solution, wherein the stirring speed may be 50 rpm to 1000 rpm, preferably 100 rpm to 900 rpm, and more preferably 400 rpm to 900 rpm. When the stirring speed satisfies the above range, a precursor with a high degree of sphericity can be formed.

[0078]

[0079] (2) Particle growth stage

[0080] When precursor seeds are formed in the reaction solution through the above process, the metal solution, ammonium cation complex forming agent, and basic solution are supplied to the reaction solution containing the precursor seeds while stirring to grow the precursor particles.

[0081] In the particle growth stage, the pH of the reaction solution may be 9 to 12, preferably 10.5 to 12, and more preferably 11 to 12. If the pH of the reaction solution satisfies the above range, the particle growth rate in the particle growth stage is appropriately controlled, thereby enabling the production of a precursor with a uniform particle size distribution and high sphericity. The pH of the reaction solution can be controlled by adjusting the supply amount of the basic solution.

[0082] The particle growth step can be performed at a temperature of 50°C to 70°C, preferably 55°C to 70°C, and more preferably 60°C to 70°C. When the reaction temperature of the particle growth step satisfies the above range, the growth rate of the primary particles increases, and primary particles with a large particle size can be formed.

[0083] The particle growth reaction can be carried out for 50 to 100 hours, preferably 60 to 90 hours, and more preferably 60 to 80 hours. When the reaction time satisfies the above range, a precursor having an appropriate particle size and high particle size distribution and sphericity can be produced.

[0084] In the particle growth stage, the stirring speed of the reaction solution may be 100 rpm to 800 rpm, preferably 200 rpm to 600 rpm. When the stirring speed satisfies the above range, it has the effect of preventing secondary particle aggregation.

[0085]

[0086] When the average particle size of the precursor particles in the reaction solution reaches the desired particle size, the reaction is terminated, the precursor is separated from the reaction solution through filtration or the like, and then washing and drying are performed to obtain a precursor for the cathode active material.

[0087]

[0088] According to the above method, a precursor for a positive electrode active material can be manufactured having a narrow particle size distribution and a high degree of sphericity compared to conventional methods.

[0089]

[0090] Precursor for positive electrode active material

[0091] Next, a precursor for an anode active material according to the present invention will be described.

[0092] The precursor for a positive electrode active material according to the present invention may be manufactured by the method for manufacturing a precursor for a positive electrode active material of the present invention described above.

[0093] The precursor for an anode active material according to the present invention comprises a transition metal hydroxide having a nickel content of 50 mol% or more, 50 mol% to 98 mol%, 50 mol% to 95 mol%, or 50 mol% to 80% among the total metals.

[0094] For example, the above transition metal hydroxide may be a compound having a composition represented by the following [Chemical Formula 1].

[0095] [Chemical Formula 1]

[0096] Ni a Co b M 1 c M 2 d (OH)2

[0097] In the above [Chemical Formula 1], M 1 It may be Mn, Al, or a combination thereof, and preferably may be Mn or a combination of Mn and Al.

[0098] M 2 It may include one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, Sr, and Nb.

[0099] The above a is the mole fraction of Ni among the total metals in the precursor, and may be 0.5≤a<1, 0.5≤a≤0.98, 0.5≤a≤0.95, or 0.5≤a≤0.80.

[0100] The above b is the mole fraction of Co among the total metals in the precursor, 0 <b<0.5, 0.01≤b<0.5 또는 0.01≤b<0.45일 수 있다.

[0101]

[0102] *98 The above c is M among the total metals in the precursor. 1 As the mole fraction of an element, 0 <c<0.5, 0.01≤c<0.5 또는 0.01≤c<0.45일 수 있다.

[0103] The above d is M among the total metals in the precursor. 2 The mole fraction of the element can be 0≤d≤0.2, 0≤d≤0.15, or 0≤d≤0.1.

[0104]

[0105] The above transition metal hydroxide may be in the form of secondary particles formed by the aggregation of multiple primary particles. The primary particles may have an average particle size of 0.1 μm to 1.2 μm, preferably 0.15 μm to 1 μm, and more preferably 0.3 μm to 0.6 μm. When the average particle size of the primary particles satisfies the above range, primary particles of an appropriate size can be realized when manufacturing a positive electrode active material, particularly a single-particle type positive electrode active material.

[0106] Meanwhile, the average particle size of the above secondary particles, i.e., D 50 It may be 2㎛ to 17㎛, 2㎛ to 15㎛, 2㎛ to 10㎛, 2㎛ to 8㎛, or 2㎛ to 6㎛.

[0107] The precursor for a positive electrode active material according to the present invention may have a span value defined by the following formula (1) of 0.8 or less, 0.1 to 0.8, or 0.3 to 0.75. When the span value satisfies the above range, primary particles grow uniformly during the manufacture of the positive electrode active material, thereby enabling the production of a positive electrode active material with excellent electrochemical performance. When the span value exceeds 0.8, problems may arise during the manufacture of the positive electrode active material, such as an increase in defects within the crystal structure or uneven grain growth.

[0108] Equation (1): Span = (D 90 - D 10 ) / D 50

[0109] In the above equation (1), D 10 , D 50 and D 90 These are the particle sizes when the cumulative volume is 10 vol%, 50 vol%, and 90 vol%, respectively, in the cumulative volume particle size distribution of the precursor for the positive electrode active material.

[0110] The precursor for the positive electrode active material according to the present invention is F defined by the following formula (2). PS The value may be 0.2 or more, 0.2 to 0.7, 0.2 to 0.5, or 0.3 to 0.5. FPS If the value satisfies the above range, the degree of sphericity of the cathode active material manufactured using it is high, and the effect of improving lifespan characteristics can be obtained. F of the precursor PS If the value is less than 0.2, the degree of sphericity of the cathode active material manufactured using this may decrease, and the lifespan characteristics may be degraded.

[0111] Equation (2): F PS = S / (D 50 ) 0.5

[0112] In the above equation (2), S is the degree of sphericity of the precursor for the positive active material, and D 50 is the particle size when the cumulative volume is 50 vol% in the volume cumulative particle size distribution of the above-mentioned precursor for the positive active material.

[0113] The degree of sphericity S may be 0.65 or higher, 0.65 to 1, or 0.65 to 0.9. When the degree of sphericity satisfies the above range, uniform grain growth occurs during the manufacture of the positive active material, thereby enabling the production of a positive active material with excellent lifespan characteristics.

[0114] The precursor according to the present invention has a BET specific surface area of ​​10 m² 2 / g to 30m 2 / g, 15m 2 / g to 30m 2 / g, or 15m 2 / g to 25m 2 It can be / g. If the BET specific surface area of ​​the precursor satisfies the above range, it exhibits excellent reactivity with lithium during the manufacture of the cathode active material and promotes grain growth, making it effective for the manufacture of single-particle cathode active materials.

[0115] The precursor according to the present invention has a tap density of 0.8 g / cm³ 3 Up to 2.5 g / cm² 3 , 1g / cm 3 Up to 2g / cm² 3 , or 1.2 g / cm³ 3 Up to 1.8 g / cm² 3It could be.

[0116]

[0117] positive electrode active material

[0118] Next, the positive electrode active material according to the present invention will be described.

[0119] The positive electrode active material according to the present invention is manufactured using the precursor for the positive electrode active material of the present invention described above, and specifically, may be a calcined product of a mixture of the precursor for the positive electrode active material of the present invention and a lithium-containing raw material.

[0120]

[0121] The positive electrode active material according to the present invention may be manufactured using a method for manufacturing a positive electrode active material known in the art, except for using a precursor for a positive electrode active material according to the present invention, and such method is not particularly limited. Since the specific details of the precursor for a positive electrode active material according to the present invention are the same as those described above, a detailed description is omitted.

[0122] The above lithium-containing raw materials may include lithium-containing carbonates (e.g., lithium carbonate, etc.), hydrates (e.g., lithium hydroxide hydrate (LiOH·H2O), etc.), hydroxides (e.g., lithium hydroxide, etc.), nitrates (e.g., lithium nitrate (LiNO3), etc.), chlorides (e.g., lithium chloride (LiCl), etc.), and one of these alone or a mixture of two or more may be used.

[0123] The mixing of the precursor for the positive electrode active material and the lithium-containing raw material can be carried out by solid-state mixing such as jet milling, and the mixing ratio of the precursor for the positive electrode active material and the lithium-containing raw material can be determined within a range that satisfies the mole fraction of each component in the finally manufactured positive electrode active material.

[0124] Meanwhile, although not essential, in addition to the precursor for the cathode active material and the lithium-containing raw material, raw materials for doping some of the transition metals and / or oxygen of the cathode active material may be additionally included in the above mixture. For example, in the above mixture, the aforementioned M 1 Containing raw materials and / or M 2 In addition, the containing raw material or the X-containing raw material described below may be mixed. In this case, the X-containing raw material may be, for example, Na3PO4, K3PO4, Mg3(PO4)2, AlF3, NH4F, LiF, etc., but is not limited thereto. When a portion of oxygen is replaced by the X element as described above, the effect of suppressing oxygen desorption and reaction with the electrolyte during the charging and discharging of the secondary battery can be obtained.

[0125] Meanwhile, the above firing may be performed at 750°C to 980°C, preferably 800°C to 900°C, and the firing time may be 5 to 30 hours, preferably 8 to 15 hours, but is not limited thereto.

[0126] If necessary, a washing step and a drying step to remove lithium by-products after the above calcination may be additionally performed. The washing step may be performed, for example, by adding a lithium composite metal oxide to ultrapure water and stirring. At this time, the washing temperature may be 20°C or lower, preferably 10°C to 20°C, and the washing time may be 10 minutes to 1 hour. When the washing temperature and washing time satisfy the above ranges, lithium by-products can be effectively removed.

[0127]

[0128] The positive active material according to the present invention has an average particle size D 50 This may be 2㎛ to 17㎛, 2㎛ to 15㎛, 2㎛ to 10㎛, 2㎛ to 8㎛, or 2㎛ to 6㎛.

[0129] The positive electrode active material according to the present invention may include a lithium complex transition metal oxide comprising lithium and nickel, and, for example, may include a lithium nickel-based oxide having a composition represented by the following [Chemical Formula 2].

[0130] [Chemical Formula 2]

[0131] Li 1+x [Ni a1 Co b1 M 1 c1 M 2 d1 ]O2

[0132] In the above [Chemical Formula 2], M 1 It may be Mn, Al, or a combination thereof, and preferably may be Mn or a combination of Mn and Al.

[0133] M 2 It may include one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb.

[0134] The above 1+x represents the molar ratio of lithium, and may be -0.2≤x≤0.2, -0.15≤x≤0.15, or -0.1≤x≤0.1.

[0135] The above a1 is the mole fraction of Ni among all metals excluding lithium, and may be 0.5≤a1<1, 0.5≤a1≤0.98, 0.5≤a1≤0.95, or 0.5≤a1≤0.80.

[0136] The above b1 is the mole fraction of Co among all metals excluding lithium, 0 <b1<0.5, 0.01≤b1<0.5 또는 0.01≤b1<0.45일 수 있다.

[0137] The above c1 is M among all metals excluding lithium. 1 As the mole fraction of an element, 0 <c1<0.5, 0.01≤c1<0.5 또는 0.01≤c1<0.45일 수 있다.

[0138] The above d1 is M among all metals excluding lithium. 2The mole fraction of the element can be 0≤d≤0.2, 0≤d≤0.15, or 0≤d≤0.1.

[0139] The above lithium nickel-based oxide may be a single-particle lithium nickel-based oxide containing 30 or fewer primary particles.

[0140] In the present invention, "single particle type" refers to a particle composed of 30 or fewer primary particles, and is a concept that includes a single particle composed of one primary particle and a pseudo-single particle which is a complex of 2 to 30 primary particles.

[0141] In the case of lithium nickel-based oxides in the form of secondary particles aggregated from more than 30 to hundreds of primary particles, side reactions with the electrolyte occur frequently due to the large contact area with the electrolyte, and gas is generated during these side reactions. Under high temperature and / or high voltage conditions, the amount of gas generated and side reactions with the electrolyte increase further, causing the performance of the lithium secondary battery to degrade rapidly. In contrast, single-particle lithium nickel-based oxides have a small number of primary particles constituting the particles, and consequently, fewer interfaces within the particles, resulting in a small contact area with the electrolyte. Therefore, compared to secondary particles, side reactions with the electrolyte are less frequent, and consequently, the amount of gas generated is significantly lower. Thus, when single-particle lithium nickel-based oxides are applied as cathode active materials, the degradation of lifespan characteristics can be minimized under high temperature and / or high voltage conditions.

[0142] The above single-particle lithium nickel-based oxide preferably comprises 30 or fewer primary particles, preferably 1 to 25, and more preferably 1 to 15 primary particles. If the number of primary particles constituting the lithium nickel-based oxide exceeds 30, particle breakage increases during electrode manufacturing, and the occurrence of internal cracks due to volume expansion / contraction of nodules during charging and discharging increases, which may reduce the improvement effect on high-temperature life characteristics and high-temperature storage characteristics.

[0143] The primary particles of the above-mentioned single-particle lithium nickel-based oxide may have an average particle size of 0.8 μm to 4.0 μm, preferably 0.8 μm to 3 μm, and more preferably 1.0 μm to 3.0 μm. When the average particle size of the nodules satisfies the above range, particle breakage is minimized during electrode manufacturing, and the increase in resistance can be suppressed more effectively. At this time, the average particle size of the nodules refers to a value obtained by measuring the particle sizes of the primary particles observed in the SEM image obtained by analyzing the cathode active material powder with a scanning electron microscope, and then calculating the arithmetic mean of the measured values.

[0144] The above lithium nickel-based oxide may further include a coating layer on its surface comprising one or more elements selected from the group consisting of Ti, Mg, Al, Zr, Y, Ba, Ca, Sr, W, Ta, Nb, and Mo.

[0145] When a coating layer is present on the surface of a lithium nickel-based oxide, contact between the electrolyte and the lithium nickel-based oxide is suppressed by the coating layer. This reduces the leaching of transition metals or gas generation caused by side reactions with the electrolyte, thereby further improving stability during thermal runaway. Preferably, the coating layer may include two or more elements selected from the group consisting of Ti, Mg, Al, Zr, Y, Ba, Ca, Sr, W, Ta, Nb, and Mo, and more preferably, may include two or more elements selected from the group consisting of Ti, Mg, Al, Zr, Y, and W.

[0146] The positive electrode active material according to the present invention is manufactured using a precursor with high particle size uniformity and sphericity, and thus possesses excellent particle size uniformity and sphericity.

[0147]

[0148] anode

[0149] The anode according to the invention comprises the anode active material of the present invention as described above. Specifically, the anode comprises an anode current collector and an anode active material layer formed on the anode current collector, wherein the anode active material layer comprises the anode active material according to the present invention. Since the anode active material has been described above, a detailed explanation is omitted, and only the remaining components are described in detail below.

[0150] The positive current collector may include a highly conductive metal, and is not particularly limited as long as it facilitates the adhesion of the positive active material layer and is non-reactive within the voltage range of the battery. The positive current collector may be, for example, stainless steel, aluminum, nickel, titanium, heat-treated carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. Additionally, the positive current collector may typically have a thickness of 3 μm to 500 μm, and fine irregularities may be formed on the surface of the current collector to increase the adhesion of the positive active material. It may be used in various forms, such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics.

[0151] The above positive active material layer may, together with the positive active material, optionally include a positive conductive material and a positive binder as needed.

[0152] At this time, the positive active material may be included in an amount of 80% to 99% by weight, more specifically 90% to 98% by weight, based on the total weight of the positive active material layer.

[0153] The above-mentioned positive electrode conductive material is used to impart conductivity to the electrode, and in the battery being constructed, it may be used without special limitations as long as it possesses electronic conductivity without causing chemical changes. 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 fibers; metal powder or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more may be used. The above-mentioned positive electrode conductive material may be included in an amount of 0.01% to 10% by weight, preferably 0.1% to 8% by weight, and more preferably 0.1% to 5% by weight, based on the total weight of the positive electrode active material layer.

[0154] The above-mentioned positive binder serves to improve the adhesion between positive active material particles and the adhesion between the positive active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, polyacrylic acid, and polymers in which hydrogens thereof are substituted with Li, Na, or Ca, or various copolymers thereof, and one of these alone or a mixture of two or more may be used. The above anode binder may be included in an amount of 0.1% to 10% by weight, preferably 1% to 10% by weight, and more preferably 1% to 8% by weight, based on the total weight of the anode active material layer.

[0155] The above-described anode can be manufactured according to a conventional anode manufacturing method, except for using the above-described anode active material. Specifically, it can be manufactured by applying an anode slurry composition, prepared by dissolving or dispersing the above-described anode active material and, if necessary, optionally a binder, a conductive material, and a dispersant in a solvent, onto an anode current collector, and then drying and rolling.

[0156] The above solvent may be a solvent generally used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethyl formamide (DMF), acetone, or water, and one of these alone or a mixture of two or more may be used. The amount of the above solvent used is sufficient if it is sufficient to dissolve or disperse the anode active material, conductive material, binder, and dispersant, taking into account the coating thickness of the slurry and the manufacturing yield, and to have a viscosity that can exhibit excellent thickness uniformity when coated for anode manufacturing thereafter.

[0157] In addition, the anode may also be manufactured by casting the anode slurry composition onto a separate support and then laminating the film obtained by peeling off from the support onto an anode current collector.

[0158]

[0159] lithium secondary battery

[0160] Next, a lithium secondary battery according to the present invention will be described.

[0161] A lithium secondary battery according to the present invention comprises a positive electrode according to the present invention as described above, specifically comprising a positive electrode, a negative electrode positioned opposite to the positive electrode, and an electrolyte, and may optionally further comprise a separator interposed between the positive electrode and the negative electrode.

[0162] Since the anode is the same as previously explained, a detailed explanation is omitted, and only the remaining components are described in detail below.

[0163] In a lithium secondary battery according to the present invention, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector.

[0164] The above-mentioned negative 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, heat-treated carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy may be used. In addition, the above-mentioned negative current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding strength of the negative active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0165] The above-mentioned cathode active material layer includes, together with the cathode active material, a cathode binder and a cathode conductive material optionally.

[0166] As the negative electrode active material, compounds capable of reversible intercalation and deintercalation of lithium may be used. 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 alloys, Sn alloys, or Al alloys; and SiO₂ βExamples include metal oxides capable of doping and dedoping lithium, such as (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the metal compound and carbonaceous material, such as Si-C composites or Sn-C composites, and any one or more of these may be used. Additionally, a metallic lithium thin film may be used as the negative electrode active material. Furthermore, the carbon material may include low-crystallinity carbon and high-crystallinity carbon. Representative examples of low-crystallinity carbon include soft carbon and hard carbon, while representative examples of high-crystallinity carbon include amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature heat-treated carbons such as petroleum and coal tar pitch-derived cokes.

[0167] The above-mentioned negative electrode active material may be included in an amount of 80% to 99% by weight, 82% to 99% by weight, or 84% to 99% by weight based on the total weight of the negative electrode active material layer.

[0168] The above-mentioned cathode conductive material is a component for further improving the conductivity of the cathode active material, and may be included in an amount of 0.1% to 10% by weight, 0.1% to 8% by weight, or 0.2% to 8% by weight based on the total weight of the cathode active material layer. The cathode conductive material is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers or metal fibers; fluorinated carbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives may be used.

[0169] The above-mentioned cathode binder is a component that assists in the bonding between the cathode conductive material, the cathode active material, and the cathode current collector, and is typically added in an amount of 0.1% to 10% by weight, preferably 1% to 10% by weight, and more preferably 1% to 8% by weight, based on the total weight of the cathode active material layer. Examples of cathode binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0170] The above-mentioned cathode active material layer may be manufactured by applying a cathode slurry composition, prepared by dissolving or dispersing a cathode active material and optionally a cathode binder and a cathode conductive material in a solvent, onto a cathode current collector and drying it, or by casting the cathode slurry composition onto a separate support and then laminating the film obtained by peeling it off from the support onto a cathode current collector.

[0171]

[0172] In the lithium secondary battery according to the present invention, the electrolyte may be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, etc., which are usable when manufacturing a lithium secondary battery, but are not limited to these.

[0173] According to one embodiment, the electrolyte may include an organic solvent and a lithium salt.

[0174] The above organic solvent may be used without special restrictions as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the above organic solvent may include ester-based solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether-based solvents such as dibutyl ether or tetrahydrofuran; ketone-based solvents such as cyclohexanone; and aromatic hydrocarbon-based solvents such as benzene and fluorobenzene. Carbonate-based solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; 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, a directional ring, or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes may be used. Among these, a carbonate-based solvent is preferred, 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 low-viscosity linear carbonate-based compound (e.g., ethylmethyl carbonate, dimethyl carbonate or diethyl carbonate, etc.) is more preferred.

[0175] The above lithium salt may be used without special restrictions as long as it is a compound capable of providing lithium ions used in lithium secondary batteries. For example, the anion of the above lithium salt is 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 - It may be at least one selected from a group consisting of

[0176] Specifically, the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2.

[0177] It is preferable to use the above lithium salt within a concentration range of 0.1M to 4.0M, preferably 0.5M to 3.0M, and more preferably 1.0M to 2.0M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0178] In addition to the above electrolyte components, the above electrolyte may further include one or more additives for the purpose of improving the lifespan characteristics of the battery, suppressing the decrease in battery capacity, and improving the discharge capacity of the battery, such as, for example, a haloalkylene carbonate-based compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride. In this case, the additive may be included in an amount of 0.1 to 10.0 weight% based on the total weight of the electrolyte.

[0179] As the above-mentioned solid inorganic electrolyte, nitrides, halides, sulfides, sulfates, etc., such as lithium, Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, or Li3PO4-Li2S-SiS2, may be used.

[0180]

[0181] In the above lithium secondary battery, the separator physically separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions. Any separator typically used in lithium secondary batteries may be used without special limitations, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte wettability. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fiber or polyethylene terephthalate fiber, may be used. Furthermore, a coated separator containing ceramic components or polymer materials may be used to ensure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0182]

[0183] The lithium secondary battery according to the present invention can be usefully applied in portable devices such as mobile phones, laptop computers, and digital cameras, and in the field of electric vehicles such as hybrid electric vehicles (HEVs).

[0184]

[0185] The present invention will be explained in more detail below through specific embodiments.

[0186]

[0187] Example 1

[0188] A 2M concentration metal solution was prepared by mixing nickel sulfate, cobalt sulfate, and manganese sulfate in water in amounts such that the molar ratio of nickel:cobalt:manganese was 6:1:3.

[0189] After adding deionized water to a co-precipitation reactor (capacity 10,000 L), an aqueous NaOH solution was added to form a reaction mother liquor with a pH of 12.

[0190] Then, a precursor seed was formed by reacting the prepared metal solution, NaOH aqueous solution, NH4OH aqueous solution, and oxygen gas in a co-precipitation reactor containing the reaction mother liquor while stirring at 800 rpm for 5 hours. At this time, the metal solution was supplied at a flow rate of 370 L / hr, and the oxygen gas was supplied such that the amount of oxygen per 1 kg of transition metal in the metal solution was 40 L.

[0191] Next, NaOH was added to the reaction solution in which the seed was formed to adjust the pH to 11.5, and precursor particles were grown by reacting at 500 rpm for 70 hours while supplying a metal solution, an aqueous NaOH solution, an aqueous NH4OH solution, and oxygen gas. At this time, the metal solution was supplied at a flow rate of 700 L / hr, and the oxygen gas was supplied such that the amount of oxygen per 1 kg of transition metal in the metal solution was 40 L.

[0192] After the reaction was completed, the reaction solution was filtered and dried to obtain the precursor powder.

[0193]

[0194] Example 2

[0195] A precursor powder was obtained in the same manner as in Example 1, except that nickel sulfate, cobalt sulfate, and manganese sulfate were mixed in water in amounts such that the molar ratio of nickel:cobalt:manganese was 9:0.5:0.5 to prepare a metal solution with a concentration of 2M.

[0196]

[0197] Example 3

[0198] A precursor powder was obtained in the same manner as in Example 1, except that a metal solution was supplied at a flow rate of 925 L / hr during the growth of the precursor particles.

[0199]

[0200] Comparative Example 1

[0201] After adding deionized water to a co-precipitation reactor (capacity 10,000 L), nitrogen gas was purged into the reactor at a rate of 6 liters / min to remove dissolved oxygen from the water and to create a non-oxidizing atmosphere inside the reactor, and then NaOH was added to form a reaction mother liquor with a pH of 12. A precursor powder was obtained in the same manner as in Example 1, except that oxygen gas was not supplied during seed formation and particle growth.

[0202]

[0203] Comparative Example 2

[0204] A precursor powder was obtained in the same manner as in Example 1, except that the metal solution was supplied at a flow rate of 500 L / hr during seed formation.

[0205]

[0206] Comparative Example 3

[0207] A precursor powder was obtained in the same manner as in Example 1, except that the metal solution was supplied at a flow rate of 230 L / hr during seed formation.

[0208]

[0209] Experimental Example 1

[0210] Particle size (D) of the precursor powder prepared in Examples 1 to 3 and Comparative Examples 1 to 3 10 , D 50 , D 90 ), sphericity, BET specific surface area, and tap density were measured as follows. The measurement results are shown in [Table 1] below.

[0211] (1) Particle size [Unit: μm]: After dispersing the precursor powder prepared in Examples 1 to 3 and Comparative Examples 1 to 3 and 1 wt% of dispersant (NaPO3)6 in water, the mixture was introduced into a Microtrac MT 3000 and irradiated with ultrasound of approximately 28 kHz at an output of 60 W. After obtaining a volume-cumulative particle size distribution graph, the particle sizes D corresponding to 10 vol%, 50 vol%, and 90 vol% of the volume-cumulative amount were... 10 , D 50 and D 90 was obtained.

[0212] (2) Sphericity: Measured using a Malvern shape / size analyzer (Malvern Sysmex FPIA-3000).

[0213] (3) BET specific surface area [Unit: m 2 [ / g]: Calculated from the amount of nitrogen gas adsorbed at liquid nitrogen temperature (77K) using BEL Japan's BELSORP-mino II.

[0214] (4) Tap density [Unit: g / cm² 3 ]: Measurements were taken by vibrating the GEOPYC 1360 tap density meter from Micromeritics until a force of 108 N was applied during its lifespan.

[0215]

[0216] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3D 10 [㎛]2.492.512.142.142.671.96D 50 [㎛]3.353.753.353.683.663.32D 90 [㎛] 4.50 4.99 4.50 6.13 5.02 4.72 SPAN 0.60 0.66 0.70 1.08 0.64 0.83 Sphericity (S) 0.75 0.79 0.65 0.35 0.38 0.45 F PS 0.4090.4080.3550.1820.1980.25BET [m 2 / g]19.49 15.15 19.6 18.16 18.56 20.1 Tab Density [g / cm² 3]1.281.281.231.261.261.21

[0217] In addition, the precursor powders of Example 1 and Comparative Examples 1 and 2 were observed using a scanning electron microscope. Fig. 1 is a scanning electron microscope image of the precursor powder of Example 1 observed at 3K and 10K magnification, Fig. 2 is a scanning electron microscope image of the precursor powder of Comparative Example 1 observed at 3K and 10K magnification, and Fig. 3 is a scanning electron microscope image of the precursor powder of Comparative Example 2 observed at 10K magnification.

[0218] Through Table 1 and Figures 1 to 3 above, it can be confirmed that the precursor powders of Examples 1 to 3 have a more uniform particle size and higher degree of sphericity compared to the precursor powders of Comparative Examples 1 to 3.

Claims

1. A transition metal hydroxide comprising a nickel content of 50 mol% or more among the total metals, and The span value defined by the following equation (1) is 0.8 or less, and F defined by the following equation (2) PS A precursor for a positive electrode active material with a value of 0.2 or higher. Equation (1): Span = (D 90 - D 10 ) / D 50 In the above equation (1), D 10 , D 50 and D 90 These are the particle sizes when the cumulative volume is 10 vol%, 50 vol%, and 90 vol%, respectively, in the cumulative volume particle size distribution of the precursor for the positive electrode active material. Equation (2): F PS = S / (D 50 ) 0.5 In the above equation (2), S is the degree of sphericity of the precursor for the positive active material, and D 50 is the particle size when the cumulative volume is 50 vol% in the volume cumulative particle size distribution of the above-mentioned positive active material precursor.

2. In Paragraph 1, The above transition metal hydroxide is a precursor for an anode active material having a composition represented by the following [Chemical Formula 1]. [Chemical Formula 1] Ni a Co b M 1 c M 2 d (OH)2 In the above [Chemical Formula 1], M 1 is Mn, Al, or a combination thereof, and M 2 ... comprises one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, Sr, and Nb, and 0.5≤a<1, 0 <b<0.5, 0<c<0.5, 0≤d≤0.2임.

3. In Paragraph 1, The above transition metal hydroxide is in the form of secondary particles formed by the aggregation of multiple primary particles, and A precursor for a positive electrode active material, wherein the average particle size of the primary particles is 0.1 to 1.2 μm.

4. In Paragraph 1, The above D 50 A precursor for a positive electrode active material having a thickness of 2㎛ to 17㎛.

5. In Paragraph 1, The above S is a precursor for a positive electrode active material, wherein S is 0.65 or higher.

6. In Paragraph 1, The above precursor for the positive electrode active material has a BET specific surface area of ​​10 m² 2 / g to 30 m 2 / g, precursor for positive electrode active material.

7. In Paragraph 1, The above precursor for the positive electrode active material has a tap density of 0.8 g / cm³ 3 Up to 2.5 g / cm² 3 Phosphorus, precursor for positive electrode active material.

8. A seed formation step of supplying and reacting a metal solution containing 50 mol% or more of nickel among the total metals, an ammonium cation complex forming agent, and a basic solution to form a reaction solution containing a precursor seed; and The particle growth step comprises growing precursor particles by stirring while supplying the metal solution, ammonium cation complex forming agent, and basic solution to a reaction solution containing the precursor seed, and At least one of the above seed formation step and particle growth step is performed in an oxidizing atmosphere, and A method for manufacturing a precursor for an anode active material, wherein the supply flow rate of the metal solution in the seed formation step is 0.4 to 0.7 times the supply flow rate of the metal solution in the particle growth step.

9. In Paragraph 8, A method for manufacturing a precursor for an anode active material, comprising a step of introducing an oxygen-containing gas in at least one of the seed formation step and the particle growth step.

10. In Paragraph 9, A method for manufacturing a precursor for an anode active material, wherein the oxygen-containing gas is introduced in an amount such that the amount of oxygen per 1 kg of transition metal in the metal solution is 20 L to 60 L.

11. In Paragraph 8, A method for manufacturing a precursor for an anode active material, wherein the reaction time of the seed formation step is 0.03 to 0.2 times the reaction time of the particle growth step.

12. A positive active material, which is a calcined product of a mixture of a precursor for a positive active material and a lithium raw material according to Claim 1.

13. In Paragraph 12, The above positive active material is a positive active material having a composition represented by the following [Chemical Formula 2]. [Chemical Formula 2] Li 1+x [Ni a1 Co b1 M 1 c1 M 2 d1 ]O2 In the above [Chemical Formula 2], M 1 is Mn, Al, or a combination thereof, and M 2 ... comprises one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, Sr, and Nb, and -0.2≤x≤0.2, 0.5≤a1<1, 0 <b1<0.5, 0<c1<0.5, 0≤d1≤0.2임.

14. A positive electrode comprising the positive electrode active material of claim 12 or claim 13.

15. A lithium secondary battery comprising the positive electrode, the negative electrode, and the electrolyte of Claim 14.

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