Positive electrode active material precursor and method for manufacturing the same

Abstract

A positive electrode active material precursor comprising transition metal hydroxide particles is provided. The transition metal hydroxide particles have an average particle size (D50) of 8 μm to 30 μm. When the distance from the center (0) of the particle to the surface (r) is r, the transition metal hydroxide particles have an average porosity of 7% or less in the region of 0.4r to 0.6r. A positive electrode active material precursor according to one embodiment of the present invention has a large particle size of 8 μm or more, a low overall porosity, and pores are uniformly distributed within.

Description

Technology Field

[0001] The present invention relates to a positive electrode active material precursor and a method for manufacturing the same. Specifically, the present invention relates to a positive electrode active material precursor having a large particle size of 8 μm or more, low overall porosity, and pores uniformly distributed inside, and a method for manufacturing the same. Background Technology

[0002] With the increasing technological development and demand for mobile devices, the demand for rechargeable batteries as an energy source is rapidly rising. Among these rechargeable batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used.

[0003] Lithium transition metal oxides are used as cathode active materials for lithium secondary batteries; among these, lithium cobalt oxide (LiCoO2) has been primarily used due to its high operating voltage and excellent capacity characteristics. However, LiCoO2 exhibits very poor thermal properties due to the descaling of its crystal structure following lithium delithiation, and its high cost limits its mass use as a power source in fields such as electric vehicles.

[0004] As materials to replace LiCoO2, lithium manganese oxide (LiMnO2 or LiMn2O4, etc.), lithium iron phosphate compounds (LiFePO4, etc.), or lithium nickel oxide (LiNiO2, etc.) have been developed. Among these, research and development on lithium nickel oxide is being conducted more actively because it has a high reversible capacity of about 200 mAh / g, making it easy to implement large-capacity batteries. However, LiNiO2 has poor thermal stability compared to LiCoO2, and there is a problem in that if an internal short circuit occurs due to external pressure or other factors while charged, the positive active material itself decomposes, causing the battery to rupture and ignite.

[0005] Accordingly, as a method to improve the low thermal stability of LiNiO2 while maintaining its excellent reversible capacity, LiNi in which a portion of the nickel is substituted with cobalt 1-α Co α A nickel-cobalt-manganese-based lithium composite metal oxide (hereinafter simply referred to as 'NCM-based lithium oxide') has been developed, comprising O2 (α=0.1~0.3) or a portion of the nickel substituted with Mn and Co. In addition, a lithium transition metal oxide having a concentration gradient of metal composition has been proposed to address stability issues, such as the leaching of metal elements, while maintaining excellent power characteristics.

[0006] Representative methods for manufacturing such cathode active materials include the method of producing cathode active material precursors using a Continuous Strand Reactor (CSTR) and then calcining them with lithium raw materials, and the method of producing cathode active material precursors using a Batch Reactor and then calcining them with lithium raw materials. The Continuous Strand Reactor (CSTR) is a method in which raw materials are fed in to co-precipitate while simultaneously discharging precursors formed into particles, whereas the Batch Reactor is a method in which raw materials are fed in proportion to the reactor volume for a set period of time to allow for reaction, and the precursors are discharged after the reaction is completed.

[0007] Generally, the productivity of cathode active material precursors manufactured using a Continuous Strand Reactor (CSTR) can be improved by simultaneously introducing raw materials for co-precipitation and discharging the precursors. However, since the input of raw materials and the discharge of products occur simultaneously and continuously in a CSTR, variations may exist in the residence and reaction times of the cathode active material precursors produced within the reactor. Consequently, there is a problem regarding the non-uniform size and particle size distribution of the generated cathode active material precursor particles. Furthermore, while cathode active material precursors manufactured using a batch reactor exhibit uniform particle size and distribution, they suffer from lower productivity compared to those produced using a CSTR.

[0008] To compensate for the disadvantages of the aforementioned continuous reactor (CSTR) and batch reactor, a continuous filtration reactor (CFTR) has been invented that is equipped with a filter inside the reactor to continuously filter only the reaction solution inside the reactor simultaneously with the input of raw materials, thereby enabling the production of a precursor. The above-mentioned continuous filtration reactor (CFTR) compensates for the disadvantages of the continuous reactor (CSTR) and batch reactor, allowing for the production of cathode active material precursors with uniform particle size and distribution while improving productivity.

[0009] The cathode active material precursor is manufactured through nucleation and particle growth reactions within the aforementioned reactor. Conventionally, nucleation and particle growth reactions were carried out continuously within the same reactor, but to manufacture each reaction efficiently, they are sometimes carried out separately. However, when nucleation and particle growth reactions are carried out separately according to the conditions of each reaction, cracks or pore bands were observed in the internal cross-section of the manufactured cathode active material precursor. These cracks or pore bands can lead to a degradation of the performance of the subsequently manufactured cathode active material, and improvement is required.

[0010] Accordingly, the inventors completed the present invention after researching a method for manufacturing a positive electrode active material precursor having a uniform cross-section inside. Prior art literature

[0011] Republic of Korea Published Patent Application No. 2021-0079049 The problem to be solved

[0012] The present invention aims to provide a positive active material precursor having a large particle diameter of 8 μm or more, having a low overall porosity and pores uniformly distributed inside, and a method for manufacturing the same. means of solving the problem

[0013] According to the first aspect of the present invention,

[0014] The present invention provides a positive electrode active material precursor comprising transition metal hydroxide particles.

[0015] In one embodiment of the present invention, the transition metal hydroxide particles have an average particle size (D) of 8 μm to 30 μm. 50 has ).

[0016] In one embodiment of the present invention, the transition metal hydroxide particle has an average porosity of 7% or less in the region of 0.4r or more and less than 0.6r when the distance from the center (0) of the particle to the surface (r) is r.

[0017] In one embodiment of the present invention, the transition metal hydroxide particles are represented by the following chemical formula 1.

[0018] [Chemical Formula 1]

[0019] [Ni x Co y M 1 z M 2 w ](OH)2

[0020] In the above chemical formula 1, 0.5≤x<1, 0 <y≤0.5, 0<z≤0.5, 0≤w≤0.2이고,

[0021] M 1 is at least one selected from the group consisting of Mn and Al, and

[0022] M 2 is selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S, Y and combinations thereof.

[0023] In one embodiment of the present invention, the transition metal hydroxide particles have a total porosity of 3% or less.

[0024] In one embodiment of the present invention, the transition metal hydroxide particle has an S value of 0.4 or less, and the S value is calculated through the following mathematical formula 1.

[0025] [Mathematical Formula 1]

[0026]

[0027] Here, D 90 is the particle size corresponding to 90% of the volume accumulation standard, and D 50 is the particle size corresponding to 50% of the volume accumulation, and D 10 is a particle size corresponding to 10% of the volume accumulation.

[0028] In one embodiment of the present invention, the transition metal hydroxide particles have a BET specific surface area of ​​2 m² / g to 8 m² / g.

[0029] In one embodiment of the present invention, the average porosity in the region of 0.4r to 0.6r is 50% to 150% of the average porosity in the region of 0 or more and less than 0.4r.

[0030] In one embodiment of the present invention, the average porosity in the region of 0.4r to 0.6r is smaller than the average porosity in the region of 0 or more and less than 0.4r, and larger than the average porosity in the region of 0.6r or more and less than or equal to r.

[0031] According to a second aspect of the present invention,

[0032] The present invention provides a method for manufacturing an anode active material precursor comprising transition metal hydroxide particles.

[0033] In one embodiment of the present invention, the manufacturing method comprises: (1) a nucleation step of generating particles by continuously introducing a reaction solution containing a raw material of an anode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution into a reactor; and (2) a particle growth step of growing particles by introducing the particles generated in the nucleation step into a reactor and continuously introducing a reaction solution containing a raw material of an anode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution.

[0034] In one embodiment of the present invention, the particle growth step comprises two or more steps of varying the supply flow rate of the reaction solution.

[0035] In one embodiment of the present invention, the temperature and ammonia concentration are controlled equally in the nucleation step and the particle growth step.

[0036] In one embodiment of the present invention, a mother liquor with a pH of 12 to 13 is introduced into the reactor before the reaction solution is introduced in the nucleation step, and as the reaction solution is introduced in the nucleation step, the pH is finally adjusted to 11 to 11.9, and in the particle growth step, the pH is maintained at 11 to 11.9.

[0037] In one embodiment of the present invention, the reactor used in the nucleation step and particle growth step is a reactor equipped with a filtration device inside, and the reaction proceeds, and after 6 to 10 hours, the solution inside the reactor is continuously discharged to the outside.

[0038] In one embodiment of the present invention, the nucleation step is performed for 20 to 40 hours, and the particle growth step is performed for 45 to 65 hours.

[0039] In one embodiment of the present invention, the particle growth step includes an early particle growth step and a late particle growth step, and the supply flow rate of the reaction solution introduced into the reactor in the early particle growth step is the same as the supply flow rate of the reaction solution introduced into the reactor in the nucleation step, and the supply flow rate of the reaction solution introduced into the reactor in the late particle growth step is increased by 5% to 20% compared to the supply flow rate of the reaction solution introduced into the reactor in the early particle growth step.

[0040] In one embodiment of the present invention, the particle growth step is switched to a late particle growth step after 2 to 5 hours, following the reaction proceeding to an early particle growth step.

[0041] In one embodiment of the present invention, in the nucleation step, the initial stirring speed is 100 rpm to 200 rpm and the final stirring speed is 50 rpm to 80 rpm, and in the particle growth step, the initial stirring speed is 60 rpm to 100 rpm and the final stirring speed is 20 rpm to 50 rpm, and the stirring speed decreases sequentially from the initial to the final reaction. Effects of the invention

[0042] A cathode active material precursor according to one embodiment of the present invention is produced by a co-precipitation reaction including a nucleation reaction and a particle growth reaction in a continuous filtration reactor. The particle growth reaction of the co-precipitation reaction is divided into two or more stages based on the supply flow rate of the reaction solution, and the porosity inside the particles can be controlled by adjusting the supply flow rate of the reaction solution in the first stage to be the same or similar to that of the nucleation reaction. The cathode active material precursor according to one embodiment of the present invention has a large particle diameter of 8 μm or more, has low overall porosity, and has pores uniformly distributed inside. In particular, the porosity of the particles grown at the location where the manufacturing process transitions from the nucleation stage to the particle growth stage is low. Brief explanation of the drawing

[0043] FIG. 1 is a schematic diagram showing an exemplary continuous filtration reactor used in the manufacture of a positive electrode active material precursor according to one embodiment of the present invention. Figure 2 is an SEM image of the cross-section of the positive active material precursor particle of Example 1 measured in Experimental Example 1. Figure 3 is an SEM image of the cross-section of the positive active material precursor particle of Comparative Example 1 measured in Experimental Example 1. Figure 4 is a graph of the pore distribution for the positive active material precursor particles of Example 1 and Comparative Example 1 measured in Experimental Example 3. Specific details for implementing the invention

[0044] All embodiments provided according to the present invention can be achieved by the following description. It should be understood that the following description describes preferred embodiments of the present invention and that the present invention is not necessarily limited thereto.

[0045] Where measurement conditions and methods are not specifically described for the physical properties described in this specification, said physical properties are measured according to measurement conditions and methods generally used by a person skilled in the art.

[0047] <Cathode active material precursor>

[0049] The present invention provides a positive active material precursor having a large particle diameter of 8 μm or more, having a low overall porosity and uniformly distributed pores inside, and a method for manufacturing the same. A positive active material precursor according to one embodiment of the present invention can be manufactured by dividing the particle growth reaction of the co-precipitation reaction into two or more stages based on the supply flow rate of the reaction solution, and controlling the porosity inside the particle while adjusting the supply flow rate of the reaction solution in the first stage to be the same or similar to that of the nucleation reaction.

[0050] According to one embodiment of the present invention, the positive active material precursor comprises transition metal hydroxide particles. The positive active material precursor may be represented by the following chemical formula 1.

[0051] [Chemical Formula 1]

[0052] [Ni x Co y M 1 z M 2 w ](OH)2

[0053] In the above chemical formula 1, 0.5≤x<1, 0 <y≤0.5, 0<z≤0.5, 0≤w≤0.2이고,

[0054] M 1 is at least one selected from the group consisting of Mn and Al, and

[0055] M 2 is at least one selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S and Y.

[0056] The above-mentioned positive active material precursor may further include having a concentration gradient, wherein Ni, Co, M from the center of the particle to the surface 1 and M 2 At least one of the elements may increase or decrease while exhibiting a gradually changing concentration gradient. For example, if the concentration of the metal within the cathode active material precursor particle has a concentration gradient that gradually changes depending on the location, there is no abrupt phase boundary region from the center of the particle to the surface, thereby stabilizing the crystal structure and increasing thermal stability.

[0057] According to one embodiment of the present invention, the transition metal hydroxide particles have an average particle size (D) of 8 μm to 30 μm. 50 It has ). The average particle size (D of the above particles 50 ) can be measured by the method described in the experimental examples below, and is a particle size corresponding to 50% of the volume accumulation in the particle size measuring device, which can also be interpreted as an average value of the particle size. Specifically, the average particle size (D) of the above particle 50 The particle size is 8㎛ or more, 9㎛ or more, 10㎛ or more, 11㎛ or more, 12㎛ or more, 30㎛ or less, 29㎛ or less, 28㎛ or less, 27㎛ or less, 26㎛ or less, 25㎛ or less, 24㎛ or less, 23㎛ or less, 22㎛ or less, 21㎛ or less, 20㎛ or less, and may be 8㎛ to 30㎛, 10㎛ to 25㎛, or 12㎛ to 20㎛. The above particle size may correspond to a large particle size as a cathode active material precursor, and may be manufactured to that size by sufficiently growing the particles after nucleation in a co-precipitation reaction.

[0058] The above transition metal hydroxide particles have a relatively uniform particle size distribution. According to one embodiment of the present invention, the transition metal hydroxide particles have an S value of 0.43 or less. The S value is also referred to as the Span value and is calculated through the following Equation 1.

[0060] [Mathematical Formula 1]

[0061]

[0063] Here, D 90 is the particle size corresponding to 90% of the volume accumulation standard, and D 50 is the particle size corresponding to 50% of the volume accumulation, and D 10 S is the particle size corresponding to 10% of the cumulative volume. Since the numerator and denominator of the above S value are calculated in the same unit, it does not have a special unit. A small S value means that the particle size variation of the particles is not large and they are uniform. Specifically, the S value of the above transition metal hydroxide particles is 0.43 or less, 0.42 or less, 0.41 or less, 0.4 or less, 0.39 or less, 0.38 or less, greater than 0, 0.1 or more, 0.15 or more, 0.2 or more, and may be 0.1 to 0.43, 0.15 to 0.41, or 0.2 to 0.4. Because the above transition metal hydroxide particles have a small S value, they possess stable performance when applied to a battery.

[0064] The transition metal hydroxide particles have a uniform particle size and a dense interior, and thus have a relatively low specific surface area. According to one embodiment of the present invention, the transition metal hydroxide particles have a BET specific surface area of ​​2 m² / g to 8 m² / g. The BET specific surface area of ​​the particles can be measured by the method described in the experimental examples below. Specifically, the BET specific surface area of ​​the transition metal hydroxide particles may be 2 m² / g or more, 2.5 m² / g or more, 3 m² / g or more, 3.5 m² / g or more, 4 m² / g or more, 8 m² / g or less, 7.5 m² / g or less, 7 m² / g or less, 6.5 m² / g or less, 6 m² / g or less, 2 m² / g to 8 m² / g, 3 m² / g to 7 m² / g, and 4 m² / g to 6 m² / g. The BET specific surface area of ​​the above particles can further enhance the functionality of the particles within the range described above.

[0065] The above transition metal hydroxide particles have a low total porosity and pores are uniformly distributed within. The porosity and pore distribution of the particles can be measured by the method described in the experimental examples below. According to one embodiment of the present invention, the total porosity of the transition metal hydroxide particles is 3% or less. The total porosity refers to the volume of internal pores of the particles relative to the total volume of the particles. Specifically, the total porosity of the transition metal hydroxide particles may be 3% or less, 2.9% or less, 2.8% or less, 2.7% or less, 2.6% or less, 2.5% or less, 0.5% or more, 0.6% or more, 0.7% or more, 0.8% or more, 0.9% or more, 1% or more, and may be 0.5% to 3%, 0.7% to 2.7%, or 1% to 2.5%. The overall porosity of the above particles can further enhance the functionality of the particles within the aforementioned range.

[0066] The above transition metal hydroxide particles have pores uniformly distributed within them, which can be confirmed through the pore distribution from the center of the particle to the surface. In this specification, the center of the particle is designated as 0, and the surface of the particle is designated as r, with any location within the particle indicated by a corresponding ratio. The center of the particle is defined as the centroid of the particle contour extracted from the SEM image. The surface of the particle is defined as the particle contour extracted from the SEM image. Therefore, if the particle is not perfectly spherical, the value of r, which is the distance from the center of the particle to a point on the surface of the particle, is not specified as a single value. The pore distribution is evaluated based on the cross-sectional or projected shape of the particle observed in the SEM image, and the specific method follows the method described in Experimental Example 3. Generally, large-diameter transition metal hydroxide particles may have characteristic pore distributions in regions of 0 to less than 0.4r, 0.4r to less than 0.6r, and 0.6r to less than r, respectively, and the region of 0.4r to less than 0.6r is a location formed when the nucleation reaction is converted to a particle growth reaction, and generally, a pore band in which a large number of pores are distributed may be formed in that region.

[0067] According to one embodiment of the present invention, the transition metal hydroxide particle has an average porosity of 7% or less in a region of 0.4r or more and less than 0.6r when the distance from the center (0) of the particle to the surface (r) is r. Specifically, the average porosity in the region may be 7% or less, 6.5% or less, 6% or less, 5.5% or less, 5% or less, 4.5% or less, 4% or less, 3.5% or less, 3% or less, 0.5% or more, 1% or more, 1.5% or more, 2% or more, and may be 0.5% to 7%, 1% to 6%, or 2% to 5%. Since the porosity of the transition metal hydroxide particle in the region is not significantly high, a clear pore band does not appear.

[0068] According to one embodiment of the present invention, the average porosity in the region of 0.4r to 0.6r is 50% to 150% relative to the average porosity in the region of 0 or more and less than 0.4r. Specifically, the ratio may be 50% or more, 55% or more, 60% or more, 150% or less, 140% or less, 130% or less, 120% or less, 110% or less, 100% or less, 90% or less, 80% or less, and may be 50% to 150%, 55% to 120%, and 60% to 90%. The transition metal hydroxide particles do not exhibit a significantly larger porosity in the pore band region of 0.4r to 0.6r than the porosity in the central region of 0 or more and less than 0.4r.

[0069] According to one embodiment of the present invention, in the region of 0.4r to 0.6r, the average porosity is smaller than the average porosity in the region of 0 or more and less than 0.4r, and is larger than the average porosity in the region of 0.6r or more and less than or equal to r. The porosity of the transition metal hydroxide particles may increase in some sections as it moves away from the center of the particles, but generally tends to decrease.

[0070] A positive electrode active material precursor according to one embodiment of the present invention has a large particle size and low overall porosity, and pores are uniformly distributed within it, so that when applied to a battery, the performance of the battery can be improved. The particulate characteristics of the above-described positive electrode active material precursor may be attributed to the method of manufacturing particles described below.

[0072] <Method for manufacturing a positive electrode active material precursor>

[0074] The present invention provides a method for manufacturing a cathode active material precursor as described above. The manufacturing method comprises: (1) a nucleation step in which a reaction solution containing a raw material of a cathode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution is continuously introduced into a reactor to generate particles; and (2) a particle growth step in which particles generated in the nucleation step are introduced into a reactor, and a reaction solution containing a raw material of a cathode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution is continuously introduced to grow particles. According to one embodiment of the present invention, the particle growth reaction of the co-precipitation reaction is divided into two or more stages based on the supply flow rate of the reaction solution, and in the first stage, the supply flow rate of the reaction solution is controlled to be the same or similar to that of the nucleation reaction to control the porosity inside the particles. The cathode active material precursor manufactured in this way may have the physical properties described above.

[0075] Hereinafter, a method for manufacturing a positive electrode active material precursor according to one embodiment of the present invention will be described in detail.

[0076] Before introducing the reaction solution containing the raw material of the cathode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution into the reactor, a mother liquor may be introduced first. To compensate for the disadvantages of continuous reactors (CSTRs) and batch reactors, the reactor may be a continuous filtration reactor (CFTR) equipped with a filter inside, capable of continuously filtering only the reaction solution inside the reactor simultaneously with the introduction of raw materials to produce the precursor. The mother liquor refers to a solution that is pre-filled inside the reactor before the reaction solution containing the raw material of the cathode active material precursor is introduced. If the reaction solution containing the raw material of the cathode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution is introduced into an empty reactor, the efficiency of cathode active material precursor production decreases because a sufficient amount of reaction solution is not secured inside the reactor. Accordingly, a mother liquor with pH and [NH3] concentration conditions similar to the reaction solution is prepared first and filled inside the reactor, after which the reaction solution containing the raw material of the cathode active material precursor is introduced. The ammonium ion-containing solution and the basic solution included in the above reaction solution control the pH and [NH3] concentration conditions that change depending on the supply of raw materials for the cathode active material precursor.

[0077] The above mother liquor is largely composed of raw material supply and nitrogen purging. The raw material of the mother liquor consists of deionized water, an ammonium ion-containing solution, and a basic aqueous solution, and dissolved oxygen in the raw material of the mother liquor is removed by nitrogen purging. According to one embodiment of the present invention, the pH of the mother liquor is 12 to 13. Specifically, the pH of the mother liquor is 12 or higher, 12.1 or higher, 12.2 or higher, 13 or lower, 12.9 or lower, 12.8 or lower, 12.7 or lower, 12.6 or lower, 12.5 or lower, and may be 12 to 13, 12.1 to 12.7, or 12.2 to 12.5. According to one embodiment of the present invention, the [NH3] concentration of the mother liquor is 0.2M to 0.6M. Specifically, the [NH3] concentration of the mother liquor may be 0.2M or more, 0.25M or more, 0.3M or more, 0.6M or less, 0.55M or less, 0.5M or less, and may be 0.2M to 0.6M, 0.25M to 0.55M, or 0.3M to 0.5M. The pH conditions of the mother liquor may change as the reaction solution is added.

[0078] When the reactor is filled with mother liquor, a reaction solution containing a raw material for a positive electrode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution is continuously introduced. By introducing the reaction solution into the reactor filled with mother liquor, the reaction proceeds, allowing nuclei of positive electrode active material precursor particles to be formed. The raw material for the positive electrode active material precursor may be a transition metal-containing solution.

[0079] The transition metals included in the above transition metal-containing solution are nickel, cobalt, and M 1 (Here, M 1It may be at least one selected from the group consisting of Mn and Al, etc. Specifically, the transition metal-containing solution may include acetates, nitrates, sulfates, halides, sulfides, hydroxides, oxides, or oxyhydroxides of transition metals, and may be used without particular limitation as long as it is soluble in water.

[0080] For example, the nickel (Ni) may be included in the transition metal-containing solution as Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, NiSO4, NiSO4·6H2O, nickel fatty acid salts, or nickel halides, and at least one of these may be used. The cobalt (Co) may be included in the transition metal-containing solution as Co(OH)2, CoOOH, Co(OCOCH3)2·4H2O, Co(NO3)2·6H2O, or CoSO4·7H2O, and at least one of these may be used. The M 1 In the case of this manganese, the manganese (Mn) may be included in the transition metal-containing solution as manganese oxides such as Mn2O3, MnO2, and Mn3O4; manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylate, manganese citrate, and manganese fatty acid salts; oxyhydroxide, and manganese chloride, etc., and at least one or more of these may be used.

[0081] In addition, the above transition metal-containing solution contains nickel, cobalt, and M 1 In addition to other metallic elements (M 2 It may further include ). In this case, the metal element M 2 It may contain at least one selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S, and Y. The transition metal-containing solution may contain a metal element (M2 If ) is further included, when preparing the transition metal-containing solution, the metal element (M 2 Raw materials containing ) may be further added. The above metal element (M 2 As raw materials containing ) metal elements (M 2 At least one selected from the group consisting of acetates, nitrates, sulfates, halides, sulfides, hydroxides, oxides, or oxyhydroxides including ) may be used. For example, the metal element (M 2 In the case where ) is W, tungsten oxide, etc. can be used.

[0082] The above ammonium ion-containing solution may include at least one selected from the group consisting of NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, and (NH4)2CO3. 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. The above basic aqueous solution may include at least one selected from the group consisting of NaOH, KOH, and Ca(OH)2, and 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.

[0083] When the solution in the reactor reaches a reference level due to the input of the reaction solution, the filtered solution obtained by filtering the solution in the reactor is continuously discharged to control the solution in the reactor so that it does not exceed the reference level. The reference level refers to a state where the solution in the reactor is filled to the capacity of the reactor, and at this time, the solution in the reactor may occupy 90% to 100% of the total volume of the reactor. Once the solution in the reactor reaches the reference level, additional reaction solution cannot be supplied without discharging the solution in the reactor. Therefore, when the solution in the reactor reaches the reference level, the discharge amount of the filtered solution may be greater than the supply amount of the reaction solution. At this time, since the raw material of the cathode active material precursor or the generated cathode active material precursor particles are not discharged, the cathode active material precursor-related material becomes concentrated in the reactor, and consequently, the cathode active material precursor particles grow.

[0084] According to one embodiment of the present invention, the reactor used in the nucleation step and the particle growth step is a reactor equipped with a filtration device inside, and the reaction proceeds in each case, and after 6 to 10 hours, 7 to 9 hours, and 7 to 8 hours, the solution inside the reactor is continuously discharged to the outside.

[0085] The discharge of the solution within the reactor is achieved by using a filtration device to discharge only the reaction solution to the outside of the reactor. In this case, the positive electrode active material precursor particles are not discharged to the outside of the reactor by the filtration device, while only the solution is selectively and continuously discharged to the outside of the reactor. At this time, the filtration device may include a metal filter, specifically comprising at least one selected from the group consisting of stainless steel and carbon steel. The metal filter may include pores, and the size of the pores may be smaller than the size of the positive electrode active material precursor. When a metal filter is used as described above, the flow rate per unit area passing through the filtration device is high, allowing the solution within the reactor to be continuously discharged to the outside of the reactor within a short period of time. Accordingly, the reaction solution can be introduced into the reactor simultaneously with the discharge of the solution to the outside of the reactor. For example, if a non-woven fabric filter material is used as the filtration device, the flow rate of the solution passing through the non-woven fabric filter material is very low, so the discharge of the solution and the introduction of the reaction solution cannot be performed simultaneously. The above filtration device may be a pleated filter, and in this case, since the specific surface area of ​​the filtration device increases, the filtration flow rate per unit area can be increased by more than 5 times compared to when the same flow rate of solution per unit area is introduced into a simple filtration device of the same size.

[0086] The nucleation step and the particle growth step described above may be carried out in the same reactor or different reactors. In the particle growth step, particles generated in the nucleation step are introduced, and a reaction solution containing raw materials for the cathode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution is continuously introduced. At this time, the particles generated in the nucleation step may be introduced in the form of the final aqueous solution from the nucleation step, and water, an aqueous ammonia solution, etc., are added to adjust the pH and ammonia concentration within the reactor before the introduction of the reaction solution.

[0087] The particle growth step may be performed for a longer period than the nucleation step. According to one embodiment of the present invention, the nucleation step is performed for 20 to 40 hours, 25 to 35 hours, and 25 to 30 hours, and the particle growth step is performed for 45 to 65 hours, 45 to 60 hours, and 50 to 60 hours.

[0088] According to one embodiment of the present invention, the temperature and ammonia concentration in the nucleation step and the particle growth step are controlled to be the same. The temperature in the nucleation step and the particle growth step is controlled to 40°C to 60°C, 45°C to 60°C, and 45°C to 55°C, respectively. According to one embodiment of the present invention, the final pH of the nucleation step and the pH of the particle growth step are controlled to be the same. As the reaction solution is introduced in the nucleation step, the final pH is controlled to 11 to 11.9, 11.2 to 11.7, and 11.2 to 11.5, and the pH in the particle growth step is maintained at 11 to 11.9, 11.2 to 11.7, and 11.2 to 11.5. Here, "same" means that even if there is a slight difference between the two steps, there is no significant difference.

[0089] In the nucleation and particle growth stages, the solution in the reactor may be mixed by a stirrer, and the stirring speed in the nucleation stage may be greater than the stirring speed in the particle growth stage. According to one embodiment of the present invention, in the nucleation stage, the stirring speed at the beginning of the reaction is 100 rpm to 200 rpm, 120 rpm to 180 rpm, and 140 rpm to 160 rpm, and the stirring speed at the end of the reaction is 50 rpm to 80 rpm, 55 rpm to 75 rpm, and 60 rpm to 70 rpm. According to one embodiment of the present invention, in the particle growth stage, the stirring speed at the beginning of the reaction is 60 rpm to 100 rpm, 65 rpm to 95 rpm, and 70 rpm to 90 rpm, and the stirring speed at the end of the reaction is 20 rpm to 50 rpm, 25 rpm to 45 rpm, and 30 rpm to 40 rpm. The stirring speed may decrease sequentially from the beginning of the reaction to the end of the reaction.

[0090] The particle growth step described above may be divided into two or more stages depending on the supply flow rate of the reaction solution introduced into the reactor. According to one embodiment of the present invention, the particle growth step includes an early particle growth step and a late particle growth step. The supply flow rate of the reaction solution introduced into the reactor in the early particle growth step is the same as the supply flow rate of the reaction solution introduced into the reactor in the nucleation step, and the supply flow rate of the reaction solution introduced into the reactor in the late particle growth step is increased by 5% to 20%, 10% to 20%, or 10% to 15% compared to the supply flow rate of the reaction solution introduced into the reactor in the early particle growth step. According to one embodiment of the present invention, the particle growth step is switched to the late particle growth step after 2 to 5 hours, 2.5 to 4.5 hours, or 3 to 4 hours after the reaction proceeds to the early particle growth step.

[0091] When the particle growth stage is completed, a solution containing the positive electrode active material precursor is discharged. The positive electrode active material precursor is separated from the solution, and the positive electrode active material precursor is obtained after washing and drying. The washing and drying are performed according to methods generally known in the art.

[0092] FIG. 1 schematically illustrates an exemplary continuous filtration reactor used for manufacturing a positive electrode active material precursor according to one embodiment of the present invention. The continuous filtration reactor (100) includes a nitrogen input channel (10) capable of supplying material to the reactor, a raw material input channel (20), a basic aqueous solution input channel (30), and an ammonium ion-containing solution input channel (40). The continuous filtration reactor (100) includes a discharge channel (50) capable of discharging material from the reactor and a filtration channel (60). The filtration channel may be composed of a filter (61) and a filter tube (62). Additionally, the continuous filtration reactor (100) includes a stirrer (70) capable of mixing material within the reactor.

[0094] Method for manufacturing positive electrode active material

[0096] A positive electrode active material can be manufactured by mixing the positive electrode active material precursor produced by the above-described manufacturing method with a lithium-containing raw material and calcining it.

[0097] The above lithium-containing raw material is not particularly limited as long as it is a compound containing a lithium source, but preferably, at least one selected from the group consisting of lithium carbonate (Li2CO3), lithium hydroxide (LiOH), LiNO3, CH3COOLi, and Li2(COO)2 may be used.

[0098] The above-mentioned positive active material precursor and lithium-containing raw material can be mixed in a molar ratio of 1:0.8 to 1:1.2. If the lithium-containing raw material is mixed in an amount less than the above range, there is a risk that the capacity of the positive active material being manufactured will decrease. If the lithium-containing raw material is mixed in an amount exceeding the above range, the particles may sinter during the calcination process, making it difficult to manufacture the positive active material, and a decrease in capacity and separation of positive active material particles after calcination (causing a phenomenon of positive active material merging) may occur.

[0099] The above calcination can be performed at a temperature of 700°C to 1000°C. If the calcination temperature is below 700°C, raw materials may remain within the particles due to insufficient reaction, which may reduce the high-temperature stability of the battery, and structural stability may decrease due to reduced bulk density and crystallinity. On the other hand, if the calcination temperature exceeds 1000°C, non-uniform growth of particles may occur, and the particle size may become too large, reducing the amount of particles that can be contained per unit area, which may reduce the volumetric capacity of the battery. Meanwhile, considering the control of particle size, capacity, stability, and reduction of lithium-containing by-products of the manufactured cathode active material, the calcination temperature may more preferably be 700°C to 950°C.

[0100] The above calcination can be performed for 5 to 35 hours. If the calcination time is less than 5 hours, the reaction time is too short, making it difficult to obtain a highly crystalline cathode active material, and if it exceeds 35 hours, the particle size may become excessively large and production efficiency may decrease.

[0102] <Cathode and Lithium Secondary Batteries>

[0104] The present invention provides a positive electrode for a lithium secondary battery comprising a positive electrode active material manufactured by the manufacturing method described above. Specifically, the positive electrode for a lithium secondary battery comprises a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, wherein the positive electrode active material layer comprises a positive electrode active material according to one embodiment of the present invention. At this time, since the positive electrode active material is the same as described above, a detailed description is omitted, and only the remaining components are described in detail below.

[0105] The above positive current collector is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the above positive current collector may typically have a thickness of 3 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. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0106] The above positive active material layer may include a conductive material and, if necessary, an optional binder together with the positive active material. In this case, the positive active material may be included in an amount of 80 to 99 weight%, more specifically 85 to 98.5 weight%, based on the total weight of the positive active material layer. Excellent capacity characteristics can be exhibited when included within the above-mentioned content range.

[0107] The above 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 fiber; metal powder or metal fiber such as copper, nickel, aluminum, or silver; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxide 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 conductive material may be included in an amount of 0.1 to 15 weight% with respect to the total weight of the positive electrode active material layer.

[0108] The above binder serves to improve adhesion between positive active material particles and adhesion between the positive active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these alone or a mixture of two or more may be used. The above binder may be included in an amount of 0.1 to 15 weight% based on the total weight of the positive active material layer.

[0109] The above-described anode may be manufactured according to a conventional anode manufacturing method, except for using the anode active material described above. Specifically, it may be manufactured by applying a composition for forming an anode active material layer, prepared by dissolving or dispersing the above-described anode active material and, optionally, a binder and a conductive material in a solvent, onto an anode current collector, and then drying and rolling.

[0110] The above solvent may be a solvent commonly used in the relevant technical field, and may include dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), 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 has a viscosity that dissolves or disperses the anode active material, conductive material, and binder, taking into account the coating thickness of the slurry and the manufacturing yield, and subsequently provides excellent thickness uniformity when coated for anode manufacturing.

[0111] Alternatively, the anode may be manufactured by casting the composition for forming the anode active material layer onto a separate support, and then laminating the film obtained by peeling off from the support onto an anode current collector.

[0113] The present invention provides an electrochemical device comprising the anode described above. Specifically, the electrochemical device may be a battery, a capacitor, etc., and more specifically, a lithium secondary battery.

[0114] Specifically, the above lithium secondary battery comprises a positive electrode, a negative electrode positioned opposite the positive electrode, and a separator and an electrolyte interposed between the positive electrode and the negative electrode. Since the positive electrode is identical to the one described above, a detailed description is omitted, and only the remaining components are described in detail below.

[0115] The above lithium secondary battery may optionally further include a battery container that accommodates the electrode assembly of the positive electrode, negative electrode, and separator, and a sealing member that seals the battery container.

[0116] In the above lithium secondary battery, the negative electrode comprises a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector.

[0117] The above-mentioned 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., and aluminum-cadmium alloy may be used. The above-mentioned negative electrode current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive electrode current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0118] The above-mentioned cathode active material layer optionally includes a binder and a conductive material together with the cathode active material.

[0119] As the above-mentioned negative electrode active material, a compound 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. Both low-crystallinity carbon and high-crystallinity carbon may be used as the carbonaceous material. 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 calcined carbon such as petroleum or coal tar pitch-derived cokes. The above-mentioned cathode active material may be included in an amount of 80% to 99% by weight based on the total weight of the cathode active material layer.

[0120] The above binder is a component that assists in the bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1% to 10% by weight based on the total weight of the negative active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0121] The above conductive material is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10% by weight or less, preferably 5% by weight or less, based on the total weight of the negative electrode active material layer. Such 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 fiber or metal fiber; metal powder such as carbon fluoride, aluminum, or nickel powder; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxide such as titanium oxide; conductive materials such as polyphenylene derivatives may be used.

[0122] For example, the cathode active material layer may be manufactured by applying and drying a composition for forming a cathode active material layer, prepared by dissolving or dispersing a cathode active material and optionally a binder and a conductive material in a solvent, onto a cathode current collector, or by casting the composition for forming a cathode active material layer onto a separate support and then laminating the film obtained by peeling from the support onto a cathode current collector.

[0123] The above-mentioned cathode active material layer may be manufactured, for example, by applying a composition for forming a cathode active material layer, prepared by dissolving or dispersing a cathode active material and optionally a binder and a conductive material in a solvent, onto a cathode current collector and drying it, or by casting the composition for forming a cathode active material layer onto a separate support and then laminating the film obtained by peeling it off from the support onto a cathode current collector.

[0124] Meanwhile, in the above-mentioned lithium secondary battery, the separator 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 can be used without special limitations, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte moisture retention capacity. 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 it may optionally be used in a single-layer or multi-layer structure.

[0125] The electrolytes used in the present invention include organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, molten inorganic electrolytes, etc., which can be used in the manufacture of lithium secondary batteries, but are not limited to these.

[0126] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0127] 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.In this case, using a mixture of cyclic carbonate and chain carbonate in a volume ratio of about 1:1 to about 1:9 can result in excellent performance of the electrolyte.

[0128] The above lithium salt can be used without special restrictions as long as it is a compound capable of providing lithium ions used in lithium secondary batteries. Specifically, the above lithium salt is LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2) 2. LiCl, LiI, or LiB(C2O4)2, etc., may be used. It is preferable to use the lithium salt within the range of 0.1 to 2.0 M. 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.

[0129] 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, haloalkylene carbonate compounds 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 above additives may be included in an amount of 0.1 to 5 weight% based on the total weight of the electrolyte.

[0130] As described above, a lithium secondary battery comprising a positive electrode active material according to one embodiment of 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, as well as in the field of electric vehicles such as hybrid electric vehicles (HEVs).

[0131] Accordingly, according to one embodiment of the present invention, a battery module comprising the lithium secondary battery as a unit cell and a battery pack comprising the same are provided.

[0132] The above battery module or battery pack can be used as a power source for one or more medium-to-large devices, including a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0133] The external shape of the lithium secondary battery according to one embodiment of the present invention is not particularly limited, but may be a cylindrical shape using a can, a prismatic shape, a pouch shape, or a coin shape.

[0134] A lithium secondary battery according to one embodiment of the present invention can be used not only as a battery cell used as a power source for a small device, but can also preferably be used as a unit cell in a medium-to-large battery module comprising a plurality of battery cells.

[0136] Hereinafter, preferred embodiments are presented to aid in understanding the present invention, but the following embodiments are provided only to facilitate a better understanding of the present invention and do not limit the present invention thereto.

[0138] Example (Preparation of positive active material precursor)

[0140] Example 1

[0141] Nucleation process:

[0142] A nitrogen atmosphere was created by introducing nitrogen gas at a rate of 10 L / hr into a continuous filtration reactor (10 m³) set to 50°C and filled with 2.75 m³ of mother liquor (pH: 12.30 ± 0.1, NH3: 6500 ± 500 ppm, H2O: 2,580 kg, NaOH: 0.02 M, NH4OH: 0.30 M). Then, an aqueous solution of the raw material of the cathode active material precursor was continuously introduced into the reactor at a rate of 717 L / hr, an aqueous ammonia solution at 96 L / hr, and an aqueous sodium hydroxide solution at 417 L / hr, respectively, and a co-precipitation reaction was carried out for 28 hours. In addition, the introduction of the aqueous sodium hydroxide solution was controlled so that the pH inside the reactor was 12.3 to 11.35. After the reaction proceeded, the reaction was carried out while gradually decreasing the stirring speed from 151 rpm to 65 rpm. After the reaction proceeded and 8 hours had elapsed, only the reaction waste liquid was continuously discharged outside the reactor through a filtration device inside the reactor. The average particle size (D) of the particles produced by the nucleation process 50 ) was 6.0㎛.

[0144] Particle growth process:

[0145] A 5.0 m³ mother liquor (pH: 11.3~11.5, NH3: 6500±500 ppm) was prepared by mixing an aqueous nucleation process solution, an amount corresponding to 3.25%~4.25% of the solid content in the solution after the nucleation process, with 4,653 kg of water and 0.35 M ammonia aqueous solution, and was filled into a continuous filtration reactor (10 m³). A nitrogen atmosphere was created by introducing nitrogen gas at a rate of 10 L / hr into the reactor, which was set to 50°C, the same as the nucleation process. Then, an aqueous solution of the raw material for the cathode active material precursor was continuously introduced into the reactor at a rate of 717 L / hr, an aqueous ammonia solution at 96 L / hr, and an aqueous sodium hydroxide solution at 417 L / hr, respectively, and the reaction was carried out for 3.5 hours at the same feeding rate. After 3.5 hours, the supply rate of the aqueous solution of the cathode active material precursor raw material was increased to 820 L / hr and the supply rate of the aqueous ammonia solution to 109 L / hr. Sodium hydroxide was injected at a supply rate of 471 L / hr, and the co-precipitation reaction was carried out for 54 hours while controlling the input of the sodium hydroxide solution to maintain the reaction solution pH within the 11.4 ± 0.1 range. After the reaction proceeded, the stirring speed was gradually reduced from 82 rpm to 35 rpm while continuing the reaction. After 7 hours of reaction time had elapsed, only the reaction waste liquid was continuously discharged to the outside of the reactor through an internal filtration device. The manufactured particles were separated, washed with water, dried in a hot-air dryer at 120°C for more than 15 hours, and sieved to obtain a final average particle size (D) of 17.0 µm. 50 Anode active material precursor (Ni) having ) 0.55 Co 0.2 Mn 0.25 (OH)2) was manufactured.

[0147] Comparative Example 1

[0148] Nucleation process:

[0149] Particles were prepared in the same manner as in Example 1.

[0151] Particle growth process:

[0152] A 5.0 m³ mother liquor (pH: 11.3–11.5, NH3: 6500±500 ppm) was prepared by mixing an aqueous nucleation process solution, an amount corresponding to 3.25%–4.25% of the solid content in the solution after the nucleation process, with 4,653 kg of water and 0.35 M aqueous ammonia solution, and was filled into a continuous filtration reactor (10 m³). A nitrogen atmosphere was established by introducing nitrogen gas at a rate of 10 L / hr into the reactor, which was set to 50°C, the same temperature as the nucleation process. The aqueous solution of the raw material for the cathode active material precursor was continuously introduced into the reactor at a rate of 820 L / hr, an aqueous ammonia solution at 109 L / hr, and an aqueous sodium hydroxide solution at 471 L / hr, respectively, and the reaction was carried out for 54 hours at the same feeding rate. The co-precipitation reaction was carried out for 54 hours while controlling the introduction of the aqueous sodium hydroxide solution. After the reaction proceeded, the stirring speed was gradually reduced from 82 rpm to 35 rpm while the reaction continued. After 7 hours of reaction time had elapsed, only the reaction waste liquid was continuously discharged to the outside of the reactor through an internal filtration device. The manufactured particles were separated, washed with water, dried in a hot-air dryer at 120°C for more than 15 hours, and sieved to obtain a final average particle size (D) of 17.0 µm. 50 Anode active material precursor (Ni) having ) 0.55 Co 0.2 Mn 0.25 (OH)2) was manufactured.

[0154] Experimental Example

[0156] Experimental Example 1 (Image of positive active material precursor particles)

[0157] Scanning electron microscope (SEM, manufacturer: Hitachi, product name: SU4800) was used to obtain SEM images (5K magnification) of the cross-sections of the cathode active material precursor particles prepared in Example 1 and Comparative Example 1, and are shown in Figures 2 and 3 below.

[0158] According to FIGS. 2 and 3, it was confirmed that the positive active material precursor particles of Example 1 had a higher degree of sphericity compared to the positive active material precursor particles of Comparative Example 1. In addition, it was confirmed that the positive active material precursor particles of Example 1 had a denser and more uniform internal structure compared to the positive active material precursor particles of Comparative Example 1.

[0160] Experimental Example 2 (Particle size of positive active material precursor particles)

[0161] The particle size distribution of the cathode active material precursor particles prepared in Example 1 and Comparative Example 1 was measured using a particle size analyzer (Manufacturer: Microtrac, Product Name: S3500). The results are shown in Table 1 below. Here, D 50 is the particle size corresponding to 50% of the volume accumulation, and D 10 is the particle size corresponding to 10% of the volume accumulation standard, and D 90 is the particle size corresponding to 90% of the volume accumulation standard, and D min is the minimum particle size corresponding to the 0% standard of the volume accumulation, and D max is the maximum particle size corresponding to 100% of the volume accumulation. In addition, the S value is calculated through the following mathematical formula 1.

[0163] [Mathematical Formula 1]

[0164]

[0166] Example 1 Comparative Example 1 D 50 (㎛) 16.97 16.95 D 10 (㎛) 13.47 12.84 D 90 (㎛) 19.96 20.90 D min (㎛) 11.23 9.03 D max (㎛) 24.05 26.92 S 0.38 0.44

[0168] According to Table 1, the positive active material precursor particles of Example 1 and the positive active material precursor particles of Comparative Example 1 had low S values ​​of 0.5 or less, showing an even particle size distribution. However, the positive active material precursor particles of Example 1 had an S value of 0.43 or less, showing a more even particle size distribution than the positive active material precursor particles of Comparative Example 1.

[0170] Experimental Example 3 (Specific surface area and pores of positive active material precursor particles)

[0171] The BET specific surface area and pores of the cathode active material precursor particles prepared in Example 1 and Comparative Example 1 were measured and are shown in Table 2 and Figure 4 below. The BET specific surface area was measured by the BET method of the specific surface area of ​​the cathode active material precursor, specifically calculated from the amount of nitrogen gas adsorbed using Micromeritics’ Tristar 2 plus. In addition, porosity was measured by obtaining an SEM image as in Experimental Example 1 and then using an image processing program (Manufacturer: LG Chem, Product Name: DX Program). In Table 2 below, the total porosity refers to the average porosity of the entire particle, and when the distance from the center (0) of the particle to the surface (r) is r, the average porosity of 0 to 0.4r refers to the average porosity in the region between 0 and less than 0.4r, the average porosity of 0.4 to 0.6r refers to the average porosity in the region between 0.4r and less than 0.6r, and the average porosity of 0.6 to 1r refers to the average porosity in the region between 0.6r and less than r. At this time, the total porosity and the porosity according to the particle radius follow the following calculation algorithm. First, the porosity according to the particle radius (f(r)) is calculated by the following mathematical formula 2.

[0173] [Mathematical Formula 2]

[0174]

[0176] Here, da represents the particle area relative to R between r and r+dr, and dp represents the pore area relative to R between r and r+dr. The above dr is defined as the 15th section where the porosity gradient according to particle radius is most distinct, and dr is 0.067R. The total porosity is expressed as P0 / A0 and is calculated by the following Equation 3 according to the relationship with Equation 2.

[0178] [Mathematical Formula 3]

[0179]

[0181] Example 1 Comparative Example 1 BET specific surface area (m² / g) 4.4 6.1 Total porosity (%) 1.87 2.04 Average porosity (%) of 0~0.4r 4.07 4.52 Average porosity (%) of 0.4~0.6r 2.84 10.44 Average porosity (%) of 0.6~1r 0.99 2.22

[0183] According to Table 2 and Figure 4, it was confirmed that the cathode active material precursor particles of Example 1 were formed with a dense and uniform interior, resulting in lower BET specific surface area and total porosity compared to the cathode active material precursor particles of Comparative Example 1. In particular, the cathode active material precursor particles of Example 1 showed a general tendency for porosity to decrease from the center of the particle to the surface, and no pore bands were observed at the transition point (0.4–0.6r) where porosity significantly increased. On the other hand, the cathode active material precursor particles of Comparative Example 1 showed a more distinct pore band at the transition point (0.4–0.6r) where porosity significantly increased.

[0185] All simple variations or modifications of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be clarified by the appended claims. Explanation of the symbols

[0186] 10: Nitrogen injection path 20: Raw material input path 30: Basic aqueous solution injection channel 40: Ammonium ion-containing solution injection channel 50: Emission Euro 60: Filtration channel 61: Filter 62: Filter tube 70: Stirrer 100: Continuous filtration reactor F1: Discharge flow of the continuous filtration reactor F2: Filtration flow of the continuous filtration reactor

Claims

Claim 1 A positive electrode active material precursor comprising transition metal hydroxide particles, wherein the transition metal hydroxide particles have an average particle size (D) of 8㎛ to 30㎛. 50 A positive electrode active material precursor having the above transition metal hydroxide particle having an average porosity of 7% or less in the region of 0.4r or more and less than 0.6r when the distance from the center (0) of the particle to the surface (r) is r. Claim 2 A positive electrode active material precursor according to claim 1, characterized in that the transition metal hydroxide particles are represented by the following chemical formula 1. [Chemical Formula 1][Ni x Co y M 1 z M 2 w ](OH)2 In the above chemical formula 1, 0.5≤x<1, 0 <y≤0.5, 0<z≤0.5, 0≤w≤0.2이고,M 1 is at least one selected from the group consisting of Mn and Al, and M 2 is selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S, Y and combinations thereof. Claim 3 A positive electrode active material precursor according to claim 1, characterized in that the transition metal hydroxide particles have a total porosity of 3% or less. Claim 4 A positive electrode active material precursor according to claim 1, wherein the transition metal hydroxide particles have an S value of 0.43 or less, and the S value is calculated through the following mathematical formula 1.[Mathematical Formula 1] Here, D 90 is the particle size corresponding to 90% of the volume accumulation standard, and D 50 is the particle size corresponding to 50% of the volume accumulation, and D 10 is a particle size corresponding to 10% of the volume accumulation. Claim 5 A positive electrode active material precursor according to claim 1, characterized in that the transition metal hydroxide particles have a BET specific surface area of ​​2 m² / g to 8 m² / g. Claim 6 A positive electrode active material precursor according to claim 1, characterized in that the average porosity in the region of 0.4r to 0.6r is 50% to 150% of the average porosity in the region of 0 or more and less than 0.4r. Claim 7 A positive electrode active material precursor according to claim 1, characterized in that the average porosity in the region of 0.4r to 0.6r is smaller than the average porosity in the region of 0 or more and less than 0.4r, and is larger than the average porosity in the region of 0.6r or more and less than or equal to r. Claim 8 A method for manufacturing a positive electrode active material precursor comprising transition metal hydroxide particles, wherein the transition metal hydroxide particles have an average particle size (D) of 8㎛ to 30㎛. 50 A method for manufacturing a positive electrode active material precursor comprising: (1) a nucleation step of generating particles by continuously introducing a reaction solution containing a raw material for a positive electrode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution into a reactor to generate particles; (2) a particle growth step of growing particles by introducing the particles generated in the nucleation step into a reactor and continuously introducing a reaction solution containing a raw material for a positive electrode active material precursor, an ammonium ion-containing solution, and a basic aqueous solution to grow particles, wherein the particle growth step comprises two or more steps of varying the supply flow rate of the reaction solution. Claim 9 A method for manufacturing a positive electrode active material precursor according to claim 8, wherein the nucleation step and the particle growth step are controlled such that the temperature and ammonia concentration are the same. Claim 10 A method for manufacturing an anode active material precursor according to claim 8, wherein a mother liquor having a pH of 12 to 13 is introduced into the reactor before the introduction of the reaction solution in the nucleation step, the pH is finally adjusted to 11 to 11.9 as the reaction solution is introduced in the nucleation step, and the pH is maintained at 11 to 11.9 in the particle growth step. Claim 11 A method for manufacturing a positive electrode active material precursor according to claim 8, wherein the reactor used in the nucleation step and particle growth step is a reactor equipped with an internal filtration device, and the reaction proceeds and the solution inside the reactor is continuously discharged to the outside after 6 to 10 hours. Claim 12 A method for manufacturing a positive electrode active material precursor according to claim 8, wherein the nucleation step is performed for 20 to 40 hours and the particle growth step is performed for 45 to 65 hours. Claim 13 A method for manufacturing a positive electrode active material precursor according to claim 8, wherein the particle growth step comprises an early particle growth step and a late particle growth step, wherein the supply flow rate of the reaction solution introduced into the reactor in the early particle growth step is the same as the supply flow rate of the reaction solution introduced into the reactor in the nucleation step, and the supply flow rate of the reaction solution introduced into the reactor in the late particle growth step is increased by 5% to 20% compared to the supply flow rate of the reaction solution introduced into the reactor in the early particle growth step. Claim 14 A method for manufacturing a positive electrode active material precursor according to claim 13, characterized in that the particle growth step is switched to a late particle growth step after 2 to 5 hours, following the reaction proceeding to an early particle growth step. Claim 15 A method for manufacturing a cathode active material precursor according to claim 8, wherein the stirring speed at the beginning of the reaction in the nucleation step is 100 rpm to 200 rpm and the stirring speed at the end of the reaction is 50 rpm to 80 rpm, the stirring speed at the beginning of the reaction in the particle growth step is 60 rpm to 100 rpm and the stirring speed at the end of the reaction is 20 rpm to 50 rpm, and the stirring speed decreases sequentially from the beginning of the reaction to the end of the reaction.

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