Positive electrode active material precursor, manufacturing method thereof, positive electrode active material, positive electrode, and electrochemical device

Abstract

The present invention provides a positive electrode active material comprising at least one of a single particle consisting of one nodule and a quasi-single particle which is a composite of 30 or fewer nodules, wherein the degree of single crystallization defined by formula (A) is 2.7 or more. Formula (A): Degree of single crystallization = [Formula I] In formula (A), Ri is a radius of an i-th grain measured when a cross-section of an electrode is subjected to electron backscatter diffraction (EBSD) analysis after ion milling treatment of the electrode manufactured by applying the positive electrode active material, and is a value measured in units of ㎛, but the value substituted into formula (A) is a unitless number that does not include a unit, and n is a total number of grains measured through the electron backscatter diffraction (EBSD) analysis.

Description

Positive electrode active material precursor, method for producing the same, positive electrode active material, positive electrode, and electrochemical device

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0117211, filed August 29, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a positive electrode active material precursor, a method for producing the same, a positive electrode active material, a positive electrode, and an electrochemical device.

[0005]

[0006] The recent rapid proliferation of battery-powered electronic devices such as mobile phones, laptops, and electric vehicles has led to a rapid increase in demand for compact, lightweight, and relatively high-capacity secondary batteries. In particular, lithium secondary batteries, with their lightweight design and high energy density, are attracting attention as power sources for portable devices. Accordingly, active research and development efforts are underway to improve the performance of lithium secondary batteries.

[0007] Lithium secondary batteries produce electrical energy through oxidation and reduction reactions when lithium ions are inserted / deintercalated from the positive and negative electrodes, while charging an organic electrolyte or polymer electrolyte between the positive and negative electrodes, which are made of active materials capable of intercalating and deintercalating lithium ions.

[0008] Lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2 or LiMn2O4, etc.), and lithium iron phosphate compound (LiFePO4) have been used as cathode active materials for lithium secondary batteries. Among these, lithium cobalt oxide (LiCoO2) is widely used due to its high operating voltage and excellent capacity characteristics, and is applied as a cathode active material for high voltage. However, due to the rising price of cobalt (Co) and unstable supply, it is difficult to use it in large quantities as a power source in fields such as electric vehicles, and the need for the development of a cathode active material that can replace it has arisen.

[0009] Accordingly, a nickel-cobalt-manganese lithium composite transition metal oxide was developed in which some of the cobalt (Co) is replaced with nickel (Ni) and manganese (Mn). Conventional lithium nickel-cobalt-manganese oxides are usually in the form of spherical secondary particles in which tens to hundreds of primary particles are aggregated. However, in the case of lithium nickel-cobalt-manganese oxides in the form of secondary particles in which many primary particles are aggregated, there is a problem in that the primary particles are easily broken during the rolling process during the manufacture of the positive electrode, and cracks occur inside the particles during the charge and discharge process. When the particles of the positive electrode active material are broken or cracked, the contact area with the electrolyte increases, which increases the generation of gases and degradation of the active material due to side reactions with the electrolyte, and this causes a problem in that the life characteristics are reduced.

[0010] To solve the above problems, a technology has been proposed for producing a single particle or pseudo-single particle type positive electrode active material rather than a secondary particle by increasing the sintering temperature during the production of lithium nickel cobalt manganese oxide. In the case of a single particle or pseudo-single particle type positive electrode active material, the contact area with the electrolyte is smaller than that of a conventional secondary particle type positive electrode active material, so there is less side reaction with the electrolyte, and the particle strength is excellent, so there is less particle breakage during electrode production. Therefore, when a single particle or pseudo-single particle type positive electrode active material is applied, there are advantages such as excellent gas generation and cycle life characteristics.

[0011] However, since single-particle or pseudo-single-particle cathode active materials are manufactured by over-sintering at high temperatures, they have many defects within the crystal structure and high strain. When defects and high strain within the crystal structure are present, the movement of lithium ions is uneven, leading to local insertion / de-insertion of lithium ions, which accelerates the degradation of the crystal structure.

[0012]

[0013] The present invention is intended to solve the above problems and to provide a positive electrode active material precursor capable of forming a positive electrode active material with improved sintering uniformity.

[0014] In addition, the present invention aims to provide a cathode active material manufactured from the cathode active material precursor and including at least one of single particles or pseudo-single particles having excellent output characteristics and lifespan characteristics.

[0015] In addition, the present invention provides a cathode and an electrochemical device having excellent energy density per unit volume, output characteristics, and high-temperature life characteristics by applying the cathode active material.

[0016]

[0017] [1] The present invention provides a cathode active material comprising at least one of a single particle composed of one nodule and a pseudo-single particle which is a composite of 30 or fewer nodules, and having a degree of crystallinity of 2.7 or more as defined by the following formula (A).

[0018] Formula (A): Single crystallinity =

[0019] In the above formula (A), R i is the radius of the i-th grain measured when an electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode cross-section is analyzed by backscatter electron diffraction (EBSD). Although the value is measured in μm, the value substituted into the above formula (A) is a unitless number that does not include a unit, and n is the total number of grains measured through the backscatter electron diffraction (EBSD) analysis.

[0020] [2] The present invention provides a positive electrode active material having a single crystallinity of 2.8 or more in the above [1].

[0021] [3] The present invention provides a positive electrode active material having a single crystallinity of 3.2 or higher in the above [1] or [2].

[0022] [4] The present invention provides a positive electrode active material having a single particle size of 0.65 or more, defined by the following formula (B), in at least one of the above [1] to [3].

[0023] Formula (B): Single particle magnetization =

[0024] In the above formula (B), R i is the radius of the i-th grain measured when the electrode cross-section is analyzed by backscatter electron diffraction (EBSD) after ion milling the electrode manufactured by applying the above positive electrode active material, and although it is a value measured in μm, the value substituted into the above formula (B) is a unitless number that does not include a unit, n is the total number of grains measured through the above backscatter electron diffraction (EBSD) analysis, and D 50 D of the above positive electrode active material 50 , and the value measured in ㎛ units or the value substituted into the above formula (B) is a unitless number that does not include a unit.

[0025] [5] The present invention provides a positive electrode active material having a single particle size of 0.75 or more in at least one of the above [1] to [4].

[0026] [6] The present invention provides a positive electrode active material comprising nickel in an amount of 50 mol% or more among all metals excluding lithium, in at least one of the above [1] to [5].

[0027] [7] The present invention provides a positive electrode active material, wherein I(003) / I(104) is 1.24 or more in at least one of the above [1] to [6].

[0028] [8] The present invention provides a positive electrode comprising at least one positive electrode active material among [1] to [7].

[0029] [9] The present invention provides an electrochemical device including the anode of the above [8].

[0030]

[0010] The present invention has a BET specific surface area of ​​16 m 2 / g exceeds, and a SPAN defined by the following formula (C) is 0.7 or less, and a pore area ratio (PAR) is 10% or more and 30% or less, a positive electrode active material precursor is provided.

[0031] Formula (C): SPAN = (D 90 -D 10 ) / D 50

[0032] In the above formula (C), D 90 Silver means the particle size at the 90% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above positive electrode active material precursor, and D 50 Silver means the particle size at the 50% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above positive electrode active material precursor, and D 10 refers to the particle size at the 10% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above-mentioned positive electrode active material precursor.

[0033]

[0011] The present invention, in the above

[0010] , the BET specific surface area is 18 m 2 / g or more than 27m 2 / g or less, a positive electrode active material precursor is provided.

[0034]

[0012] The present invention is a method for producing a compound having a BET surface area of ​​19 m in the above

[0010] or

[0011] . 2 / g or more than 25m 2 / g or less, a positive electrode active material precursor is provided.

[0035]

[0013] The present invention provides a positive electrode active material precursor, wherein the SPAN is 0.20 or more and 0.60 or less in at least one of the above

[0010] to

[0012] .

[0036]

[0014] The present invention provides a positive electrode active material precursor, wherein in at least one of the above

[0010] to

[0013] , the SPAN is 0.40 or more and 0.54 or less.

[0037]

[0015] The present invention provides a positive electrode active material precursor having a pore area ratio (PAR) of 17% or more and 30% or less in at least one of the above

[0010] to

[0014] .

[0038]

[0016] The present invention provides a positive electrode active material precursor having a pore area ratio (PAR) of 19% or more and 29% or less in at least one of the above

[0010] to

[0015] .

[0039]

[0017] The present invention provides a positive electrode active material precursor comprising nickel in an amount of 50 mol% or more among the total metals in at least one of the above

[0010] to

[0016] .

[0040]

[0018] The present invention, in at least one of the above

[0010] to

[0017] , the average particle diameter D 50 A positive electrode active material precursor having a size of more than 2.0㎛ and less than 5.0㎛ is provided.

[0041]

[0019] The present invention provides a method for producing a positive electrode active material precursor, comprising: a first step of forming a positive electrode active material precursor nucleus by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to a reactor while performing a coprecipitation reaction; and a second step of growing positive electrode active material precursor particles by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to the reaction solution in which the positive electrode active material precursor nucleus is formed while performing a coprecipitation reaction; wherein in the first step, the ammonium cation complex forming agent is supplied at a flow rate of 6 mL / hr or more and 11 mL / hr or less, and in the second step, the pH of the reaction solution is 11.4 or more.

[0042]

[0020] The present invention provides a method for manufacturing a positive electrode active material precursor, wherein, in the second step, the transition metal-containing solution is supplied at a flow rate of 730 mL / hr or less in the above

[0019] .

[0043]

[0021] The present invention provides a method for manufacturing a positive electrode active material precursor, wherein, in the above

[0019] or

[0020] , the second step is performed for 33 hours or more.

[0044]

[0045] Since the positive electrode active material precursor of the present invention has a uniform particle size distribution by controlling the SPAN value, it is capable of uniform reaction with lithium, thereby reducing defects and strain in the structure of the positive electrode active material manufactured after firing.

[0046] The cathode active material precursor of the present invention can be manufactured into a cathode active material comprising at least one single particle or pseudo-single particle without a relatively high sintering temperature by controlling the BET specific surface area to enhance reactivity with lithium raw materials. This can reduce structural defects and strain in the cathode active material that occur when exposed to high temperatures for extended periods of time.

[0047] The cathode active material precursor of the present invention facilitates crystal growth by controlling the pore area ratio (PAR), thereby enabling the production of a cathode active material comprising at least one single particle or pseudo-single particle without a relatively high sintering temperature. This allows for the provision of a cathode active material with a high degree of single particle formation while reducing defects and strain within the cathode active material structure.

[0048] The cathode active material of the present invention is manufactured using the cathode active material precursor. The cathode active material of the present invention comprises at least one of single particles and pseudo-single particles, and has a single crystallinity within a specific range, thereby exhibiting excellent particle strength, excellent structural stability, and reduced defects and strain within the structure.

[0049] The cathode and electrochemical device of the present invention can have excellent energy density per unit volume, output characteristics, and high-temperature life characteristics by applying the cathode active material.

[0050]

[0051] Terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best possible manner.

[0052] It should be understood that the terms “include,” “comprising,” or “having” used in this specification are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0053] In the present invention, a "grain" is a particle unit having the same crystal orientation, and is the smallest particle unit recognized as a single lump in an Electron Backscatter Diffraction (EBSD) map image. The size of a grain can be measured by image analysis of an EBSD map.

[0054] In the present invention, a "single particle" is a particle composed of one single nodule. In the present invention, a "quasi-single particle" means a particle that is a composite formed of 10 or fewer nodules.

[0055] In the present invention, "nodule" means a particle unit body constituting a single particle and a pseudo-single particle, and the nodule may be a single crystal lacking a crystalline grain boundary, or a polycrystal in which no grain boundary exists in appearance when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope (SEM).

[0056] In the present invention, "secondary particle" refers to a particle formed by the agglomeration of tens to hundreds of primary particles. More specifically, the secondary particle is an agglomerate of 50 or more primary particles.

[0057] The expression "particle" used in the present invention may include any one or all of single particles, quasi-single particles, primary particles, nodules, and secondary particles.

[0058] In the present invention, "Dn" means the particle diameter at the n% point of the volume cumulative distribution according to particle diameter. That is, D 50 is the particle size at the 50% point of the cumulative volume distribution according to particle size, and D 90 D is the particle size at the 90% point of the cumulative volume distribution according to particle size. 10 is the particle diameter at the 10% point of the volume cumulative distribution according to particle diameter. The above Dn can be measured using the laser diffraction method. Specifically, after the powder to be measured is dispersed in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac S3500) and the particle size distribution is calculated by measuring the difference in the diffraction pattern according to the particle size when the particles pass through the laser beam. By calculating the particle diameter at the points where it becomes 10%, 50%, and 90% of the volume cumulative distribution according to particle diameter in the measuring device, D 10 , D 50 and D 90 can be measured.

[0059] In the present invention, “the average particle diameter of the nodules (D n )" can be measured by measuring the particle size of each nodule that can be distinguished in a cross-sectional scanning electron microscope (SEM) image of the positive electrode active material and then calculating the arithmetic average of these.

[0060] In the present invention, the above “nickel disorder” is determined by obtaining XRD data using an X-ray diffractometer (Bruker, D8 Endeavor) and then performing atomic structure analysis using the Rietveld method to determine the Ni occupies the lithium site. 2+ After analyzing the relative amount of ions and the relative occupancy of oxygen in the oxygen site, the Ni irregularized in the lithium site obtained from this 2+ It can mean ion content (%).

[0061] In the present invention, "strain" refers to lattice distortion, i.e., microscopic deformation, caused by a defect. The strain was measured by analyzing XRD data obtained by X-ray diffraction analysis of a positive electrode active material powder using the Rietveld refinement method. At this time, the X-ray diffraction analysis can be performed using a Bruker D8 Endeavor equipped with a LynxEye XE-T-position sensitive detector (light source: Cu-Kα, λ=1.54Å), by placing a sample in the groove of a general powder holder, smoothing the surface of the sample using a slide glass, and filling the sample so that the height of the sample matches the edge of the holder, and then measuring under the conditions of step size=0.02°, total scan time=approximately 20 minutes for the FDS 0.5°, 2θ = 15° to 90° region. For the measured data, Rietveld refinement can be performed by considering the charge at each site (metals at the transition metal site are +3, Ni at the Li site is +2) and nickel disorder. Specifically, during strain analysis, instrumental broadening can use the Fundamental Parameter Approach (FPA) implemented in the Bruker TOPAS program, and during fitting, the entire peaks of the measurement range can be It can be used. Peak shape can be fitted using only Lorenzian contribution as FP (First Principle) among the peak types available in TOPAS.

[0062] In the present invention, the “specific surface area” is measured by the BET method, and specifically, can be calculated from the nitrogen gas adsorption amount at liquid nitrogen temperature (77K) using BELSORP-mino II of BEL Japan.

[0063]

[0064] Hereinafter, the present invention will be described in detail.

[0065] The cathode active material precursor, the method for producing the same, the cathode active material, the cathode and / or the lithium secondary battery according to the present invention comprise at least one of the following disclosed configurations, and may comprise any combination between technically possible configurations among the following configurations.

[0066]

[0067] Cathode active material precursor

[0068] The positive electrode active material precursor of the present invention may contain nickel in an amount of 50 mol% or more, 52 mol% or more, 55 mol% or more, 57 mol% or more, 60 mol% or more, 99 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, 72 mol% or less, 70 mol% or less, 67 mol% or less, 65 mol% or less, 62 mol% or less, or 60 mol% or less of the total metal. For example, the positive electrode active material precursor of the present invention may contain nickel in an amount of 50 mol% or more, 50 mol% or more and 80 mol% or less, 50 mol% or more and 70 mol% or less, 55 mol% or more and 65 mol% or less, or 57 mol% to 62 mol% or less of the total metal. When the above range is satisfied, a positive electrode active material having a high energy density can be manufactured. In particular, when the positive electrode active material precursor contains nickel in an amount of 50 to 80 mol% of the total metal, a positive electrode active material having excellent capacity characteristics and structural stability can be manufactured.

[0069]

[0070] The positive electrode active material precursor of the present invention may contain cobalt in an amount of 1 mol% or more, 3 mol% or more, 5 mol% or more, 7 mol% or more, 10 mol% or more, 20 mol% or less, 17 mol% or less, 15 mol% or less, 13 mol% or less, or 10 mol% or less of the total metal. For example, the positive electrode active material precursor of the present invention may contain cobalt in an amount of 20 mol% or less, 1 mol% or more and 17 mol% or less, 5 mol% or more and 15 mol% or less, or 7 mol% or more and 13 mol% or less of the total metal. When the above range is satisfied, a cost advantage can be achieved by containing a relatively small amount of cobalt, while a certain level or higher of output characteristics can be secured.

[0071]

[0072] The positive electrode active material precursor of the present invention may contain manganese in an amount of 1 mol% or more, 5 mol% or more, 10 mol% or more, 15 mol% or more, 20 mol% or more, 25 mol% or more, 30 mol% or more, 40 mol% or less, 38 mol% or less, 37 mol% or less, 35 mol% or less, 33 mol% or less, 32 mol% or less, or 30 mol% or less of the total metal. For example, the positive electrode active material precursor of the present invention may contain manganese in an amount of 40 mol% or less, 1 mol% or more and 38 mol% or less, 10 mol% or more and 37 mol% or less, 20 mol% or more and 33 mol% or less, or 25 mol% or more and 32 mol% or less of the total metal. When the above range is satisfied, the structural stability of the manufactured positive electrode active material may be excellent.

[0073]

[0074] The positive electrode active material precursor of the present invention may include a nickel-based hydroxide containing nickel, cobalt, and manganese.

[0075]

[0076] The positive electrode active material precursor of the present invention may have a composition represented by the following chemical formula 1 or chemical formula 2.

[0077] [Chemical Formula 1] [Ni p Co q Mn r](OH)2

[0078] [Chemical Formula 2] [Ni p Co q Mn r ]O·OH

[0079] In the above chemical formulas 1 and 2, p refers to the molar ratio of nickel among the metal elements in the precursor, and may be 0.5≤p<1.0, 0.5≤p≤0.8, 0.5≤p≤0.7, 0.55≤p≤0.65, or 0.57≤p≤0.62.

[0080] In the above chemical formulas 1 and 2, q means the molar ratio of cobalt among the metal elements in the precursor, and is 0. <q≤0.2, 0.01≤q≤0.17, 0.05≤q≤0.15, 또는 0.07≤q≤0.13일 수 있다.

[0081] In the above chemical formulas 1 and 2, r means the molar ratio of manganese among the metal elements in the precursor, and is 0. <r≤0.4, 0.01≤r<0.38, 0.05≤r≤0.37, 0.1≤r≤0.35, 0.2≤r≤0.33, 또는 0.25≤r≤0.32일 수 있다.

[0082]

[0083] The BET specific surface area of ​​the positive electrode active material precursor of the present invention is 16 m 2 / g exceeded, 17m 2 / g or more, 18m 2 / g or more, 19 m 2 / g or more, 20.0m 2 / g or more or 20.0m 2 / g may be exceeded. The BET specific surface area of ​​the positive electrode active material precursor of the present invention is 30 m 2 / g or less, 27m 2 / g or less, 26m 2 / g or less, 25m 2 / g or less, 24m 2 / g or less, or 23.5m 2 / g or less. For example, the BET specific surface area of ​​the positive electrode active material precursor of the present invention is 16 m2 / g exceeded, 17 m 2 / g or more than 30m 2 / g or less, 18 m 2 / g or more 27 m 2 / g or less, 19m 2 / g or more than 25m 2 / g or less, or 20m 2 / g or more 23.5 m 2 / g or less. When the BET specific surface area value of the positive electrode active material precursor satisfies the above range, the surface reactivity with lithium increases due to the high specific surface area of ​​the precursor, so that firing occurs well, and the resistance and output are improved through a decrease in the firing temperature.

[0084]

[0085] The positive electrode active material precursor of the present invention may have a SPAN defined by formula (C) of 0.7 or less.

[0086] Formula (C): SPAN = (D 90 -D 10 ) / D 50

[0087] In the above formula (C), D 90 Silver means the particle size at the 90% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above positive electrode active material precursor, and D 50 Silver means the particle size at the 50% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above positive electrode active material precursor, and D 10 refers to the particle size at the 10% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above-mentioned positive electrode active material precursor.

[0088] Specifically, the positive electrode active material precursor of the present invention may have a SPAN defined by the above formula (C) of 0.7 or less, 0.65 or less, 0.63 or less, 0.60 or less, 0.58 or less, 0.55 or less, 0.54 or less, 0.53 or less, 0.20 or more, 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.42 or more, 0.45 or more, or 0.48 or more. For example, the positive electrode active material precursor of the present invention may have a SPAN defined by the above formula (C) of 0.7 or less, 0.20 or more and 0.60 or less, 0.40 or more and 0.54 or less, or 0.48 or more and 0.53 or less. When the SPAN value of the positive electrode active material precursor exceeds 0.7, even if the BET specific surface area and pore area ratio of the positive electrode active material satisfy the range according to the present invention, it may react non-uniformly with lithium during the firing step, and accordingly, the crystal structure of the positive electrode active material is formed such that I(003) / I(104) is inferior, so that the movement path of lithium ions is not sufficiently secured, and thus the resistance characteristics and life characteristics of the positive electrode active material may deteriorate. Accordingly, when the SPAN value of the positive electrode active material precursor satisfies the above range, uniform firing with lithium is possible due to the uniform particle size distribution of the precursor, and this has the effect of reducing defects and strain in the structure of the positive electrode active material.

[0089]

[0090] Average particle diameter D of the positive electrode active material precursor of the present invention 50 The average particle size of the positive electrode active material precursor of the present invention may be 1 ㎛ or more, 1.5 ㎛ or more, 2 ㎛ or more, more than 2 ㎛, 2.5 ㎛ or more, 3 ㎛ or more, 3.4 ㎛ or more, 6 ㎛ or less, 5.5 ㎛ or less, 5 ㎛ or less, 4.5 ㎛ or less, 4 ㎛ or less, or 3.5 ㎛ or less. For example, the average particle size D of the positive electrode active material precursor of the present invention 50The average particle size may be 1 ㎛ or more and 6 ㎛ or less, 1 ㎛ or more and 5 ㎛ or less, 2 ㎛ or more and 5 ㎛ or more, 2.5 ㎛ or more and 4 ㎛ or less, 3.0 ㎛ or more and 4 ㎛ or less, or 3.2 ㎛ or more and 3.5 ㎛ or less. If the average particle size of the positive electrode active material precursor of the present invention is smaller than the above range, the sintering may proceed unevenly, and the manufactured positive electrode active material may have poor single crystallinity and single particle size, which may increase particle breakage during rolling and charge / discharge, and increase electrolyte side reactions, resulting in poor life characteristics. Accordingly, if the average particle size of the positive electrode active material precursor of the present invention satisfies the above range, the reaction uniformity may be improved, and the life characteristics may be excellent.

[0091] D of the positive electrode active material precursor of the present invention 90 The particle size may be 2 µm to 7 µm, 2.5 µm to 6.5 µm, 3.5 µm to 5.5 µm, 4.0 µm to 5.0 µm, 4.0 µm to 4.25 µm, or 4.07 µm to 4.20 µm. When the above range is satisfied, the SPAN value of the positive electrode active material precursor of the present invention can be appropriately controlled, and particle size uniformity can be achieved.

[0092] D of the positive electrode active material precursor of the present invention 10 The particle size may be 0.5 µm to 5 µm, 1 µm to 4 µm, 1.5 µm to 3.5 µm, 2.0 µm to 2.5 µm, or 2.3 µm to 2.45 µm. When the above range is satisfied, the SPAN value of the positive electrode active material precursor of the present invention can be appropriately controlled, and particle size uniformity can be achieved.

[0093]

[0094] The pore area ratio (PAR) of the positive electrode active material precursor of the present invention may be 10% or more and 30% or less. Specifically, the pore area ratio (PAR) of the positive electrode active material precursor of the present invention may be 10% or more, 11% or more, 12% or more, 13% or more, 14% or more, 15% or more, 16% or more, 17% or more, 18% or more, 19% or more, 20% or more, 21% or more, 22% or more, 23% or more, 24% or more, 30% or less, 29.5% or less, or 29% or less. For example, the pore area ratio (PAR) of the positive electrode active material precursor may be 10% or more and 30% or less, 15% or more and 30% or less, 17% or more and 30% or less, 19% or more and 29% or less, or 24% to 29%. When the pore area ratio (PAR) value of the positive electrode active material precursor satisfies the above range, the internal pores help crystal growth during high-temperature firing, thereby increasing the single crystallinity of the manufactured positive electrode active material, and thus the life characteristics and capacity characteristics of a battery using the positive electrode active material can be excellent.

[0095] In the present invention, the pore area ratio (PAR) refers to the ratio of the pore area to the internal area of ​​the positive electrode active material precursor particles, and specifically refers to the arithmetic mean value of the ratio of the pore area to the internal area of ​​the positive electrode active material precursor particles. Specifically, the pore area ratio (PAR) can be measured by a pore distribution analysis method by obtaining a cross-sectional image by taking a scanning electron microscope (SEM) photograph of the positive electrode active material precursor and analyzing the cross-sectional image using an image analysis program. For example, after impregnating and curing the positive electrode active material precursor with an epoxy resin or a polydimethylsiloxane (PDMS) resin, a focused ion beam (FIB) is used to cut the particles of the positive electrode active material precursor into a state where a cross-section can be observed. Thereafter, a scanning electron microscope (SEM) is used to obtain SEM cross-sectional images of a plurality of positive electrode active material precursor particles. Thereafter, using image analysis software WinRoof 6.1.1 for the acquired SEM cross-sectional images, the pores of each particle of the positive electrode precursor are indicated by shades, and the dense parts of each particle of the positive electrode precursor are indicated by white. Among the measured particles of the positive electrode precursor, the ratio (%) of 20 or more particles of the positive electrode precursor is calculated by [shaded area / (shaded area + white area) × 100], and the pore area ratio (PAR) can be obtained by obtaining the arithmetic average value.

[0096]

[0097] The positive electrode active material precursor may have a uniform pore area ratio within the positive electrode active material precursor particles. “The uniform pore area ratio within the positive electrode active material precursor particles” may mean that when the positive electrode active material precursor particles are divided into a plurality of regions (e.g., 3 or more, or 5 or more), the pore area ratio values ​​measured in the regions satisfy ±10% of the pore area ratio value of the positive electrode active material precursor.

[0098] Specifically, when the positive electrode active material precursor is defined as a seed-core-shell structure including a seed portion; a core portion positioned on the seed portion; and a shell portion positioned on the core portion, the pore area ratio of the seed portion, the pore area ratio of the core portion, and the pore area ratio of the shell portion may be the same within an error range of ±10%.

[0099] In this case, single crystals are uniformly formed in the seed portion, core portion, and shell portion during firing, so that the life characteristics can be improved.

[0100]

[0101] The BET specific surface area, pore area ratio, and SPAN value of the positive electrode active material precursor of the present invention can be organically controlled in a range by appropriately controlling the flow rate of the transition metal-containing solution, the flow rate of the cationic complex forming agent, the pH of the reaction solution, and the reaction time in the positive electrode active material nucleus formation step (step 1) during the production of the positive electrode active material precursor, and the flow rate of the transition metal-containing solution, the flow rate of the cationic complex forming agent, the pH of the reaction solution, the reaction time, and the stirring speed in the positive electrode active material precursor particle growth step (step 2).

[0102]

[0103] Method for manufacturing a cathode active material precursor

[0104] The method for manufacturing a positive electrode active material precursor of the present invention may include (1) a first step of forming a positive electrode active material precursor nucleus (seed) by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to a reactor while performing a co-precipitation reaction; and (2) a second step of growing positive electrode active material precursor particles by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to the reaction solution in which the positive electrode active material precursor nucleus is formed while performing a co-precipitation reaction.

[0105]

[0106] (1) Stage 1

[0107] First, a coprecipitation reaction is performed by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to a reactor to form a positive electrode active material precursor nucleus (seed).

[0108]

[0109] The above reactor may contain a reaction mother liquid. Specifically, before supplying the reaction raw materials, i.e., a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution, the ammonium cation complex forming agent, the basic solution, and water may be first introduced into the reactor to form a reaction mother liquid.

[0110] At this time, the ammonium cation complex forming agent may include an ammonium cation complex forming agent compound including at least one selected from the group consisting of NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, and NH4CO3, and may be introduced into the reactor in the form of a solution in which the compound is dissolved in a solvent. At this time, as the solvent, water or a mixture of water and an organic solvent (specifically, alcohol, etc.) that can be uniformly mixed with water may be used. Most preferably, NH4OH, i.e., ammonia water, may be used.

[0111] The ammonium cation complex forming agent may have a concentration including the ammonium cation complex forming agent compound of 20 wt% or less, 1 wt% to 15 wt%, 5 wt% to 12 wt%, or 7 wt% to 11 wt%.

[0112] Next, the basic solution may include at least one basic compound selected from the group consisting of NaOH, KOH, and Ca(OH)2, and may be introduced into the reactor in the form of a solution in which the compound is dissolved in a solvent. At this time, the solvent may be water, or a mixture of water and an organic solvent (specifically, alcohol, etc.) that can be uniformly mixed with water.

[0113] The basic solution may have a concentration comprising the basic compound of 10 wt% to 40 wt%, 15 wt% to 35 wt%, 20 wt% to 30 wt%, or 23 wt% to 27 wt%.

[0114] The above reaction mother liquid can be formed so that the pH is 11 to 13, or 11 to 12. When the pH of the reaction mother liquid satisfies the above range, nucleus formation can occur smoothly.

[0115] Meanwhile, an ammonium cation complex forming agent, a basic solution, and water are added to the reactor to form a reaction mother liquid, and then the reaction mother liquid is purged with nitrogen gas to remove oxygen in the reaction mother liquid.

[0116]

[0117] When a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution are supplied to a reactor containing a mother reaction solution and stirred, a coprecipitation reaction may proceed, thereby forming nuclei of a positive electrode active material precursor. Specifically, when a transition metal-containing solution, an ammonium cation complex forming agent, and a basic aqueous solution are supplied to a reactor containing a mother reaction solution and stirred, a coprecipitation reaction may proceed, thereby generating (nucleating) precursor nuclei in the form of primary particles, and when the nuclei in the form of primary particles aggregate, nuclei (seeds) in the form of secondary particles may be formed.

[0118] The ammonium cation complex forming agent and basic aqueous solution may be the same as those described above.

[0119] In the first step, the ammonium cation complex forming agent may be supplied at a flow rate of 6 mL / hr or more and 11 mL / hr or less, or 6 mL / hr or more and 10 mL / hr. When the above range is satisfied, the growth rate of the positive electrode active material precursor nucleus can be smoothly maintained, so that the pore area ratio and BET specific surface area of ​​the positive electrode active material precursor produced can be appropriately controlled.

[0120] The amount of basic solution added in the above nucleation step may be 6 mol / L to 8 mol / L, or 6 mol / L to 7 mol / L.

[0121] The above transition metal-containing solution may include nickel, cobalt and manganese elements, and may be formed by mixing a nickel raw material, a cobalt raw material and a manganese raw material in water.

[0122] The above nickel raw material may be Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, NiSO4, NiSO4·6H2O, fatty acid nickel salt or nickel halide, and any one or a mixture of two or more of these may be used, but is not limited thereto.

[0123] The above cobalt raw material may be Co(OH)2, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O or Co(SO4)2ㆍ7H2O, and any one or a mixture of two or more of these may be used, but is not limited thereto.

[0124] The above manganese raw material may be manganese oxides such as Mn2O3, MnO2, and Mn3O4; manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylic acid salt, manganese citrate, and manganese fatty acid salt; oxyhydroxide, or manganese chloride, and any one or a mixture of two or more thereof may be used, but is not limited thereto.

[0125] The above transition metal-containing solution may include a nickel raw material such that the nickel content is 50 mol% or more, 52 mol% or more, 55 mol% or more, 57 mol% or more, 60 mol% or more, 99 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, 72 mol% or less, 70 mol% or less, 67 mol% or less, 65 mol% or less, 62 mol% or less, or 60 mol% or less with respect to the entire metal. When the above range is satisfied, the capacity characteristics can be improved. The above transition metal-containing solution can further improve the capacity characteristics when the nickel content is 60 mol% or more with respect to the entire metal. The content of the transition metal included in the transition metal-containing solution supplied in the first step may be 1.0 mol / L to 3.0 mol / L, 1.5 mol / L to 2.5 mol / L, or 1.8 mol / L to 2.3 mol / L.

[0126] In the first step, the transition metal-containing solution may be supplied at a flow rate of 100 mL / hr or more, 150 mL / hr or more, 200 mL / hr or more, 250 mL / hr or more, 300 mL / hr or more, 320 mL / hr or more, 350 mL / hr or more, 600 mL / hr or less, 550 mL / hr or less, 500 mL / hr or less, 450 mL / hr or less, or 400 mL / hr or less. When the above range is satisfied, the crystal structure of the positive electrode active material precursor nucleus can be stably formed, and the growth rate can be appropriately controlled to appropriately control the BET specific surface area and pore area ratio of the positive electrode active material precursor.

[0127]

[0128] The above first step may be performed for 20 hours or less, 2 to 15 hours, 2 to 12 hours, or 5 to 11 hours. When the performance time of the first step satisfies the above range, the positive electrode active material spherical nuclei are sufficiently formed, resulting in excellent productivity and a uniform particle size distribution of the manufactured positive electrode active material precursor.

[0129] Additionally, the pH of the reaction solution in the first step may be 11 to 13, 11.5 to 12.5, or 11.9 to 12.2. When the above range is satisfied, the nuclei of the positive electrode active material precursor can be grown while appropriately controlling the density of the nuclei, so that the particle size distribution of the positive electrode active material precursor is uniform, and the BET specific surface area and pore area ratio can be controlled.

[0130] In the above first step, the temperature of the reaction solution may be 40°C to 80°C, 45°C to 80°C, 55°C to 78°C, or 65°C to 75°C. When the temperature of the reaction solution satisfies the above range, nuclei of the positive electrode active material precursors are formed within the reaction solution, and the process of the nuclei agglomerating to form nuclei can smoothly occur. The pH of the reaction solution can be controlled by adjusting the amount of alkaline solution added using a pH sensor or the like.

[0131]

[0132] (2) Stage 2

[0133] Next, when the positive electrode active material precursor nuclei are sufficiently formed through the above process, the positive electrode active material precursor particles can be grown by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to the reaction solution in which the positive electrode active material precursor nuclei are formed, and performing a co-precipitation reaction. Specifically, the positive electrode active material precursor particles can be grown by supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to the reaction solution in which the positive electrode active material precursor nuclei are formed, and stirring the solution, and performing a co-precipitation reaction.

[0134] The transition metal-containing solution, the ammonium cation complex forming agent, and the basic solution introduced in the second step may be the same as those used in the nucleus formation step.

[0135] In the second step, the pH of the reaction solution may be 11.4 or more, 11.4 or more and 12.0 or less, 11.4 or more and 11.8 or less, or 11.4 or more and 11.6 or less. When the above range is satisfied, the positive electrode active material precursor particles can be grown at an appropriate rate, so that the BET specific surface area can be appropriately controlled and the particle size distribution can be uniform.

[0136]

[0137] In the above particle growth step, the temperature of the reaction solution may be 40°C to 80°C, 45°C to 80°C, or 45°C to 75°C. When the temperature of the reaction solution satisfies the above range, particle growth can occur smoothly. The pH of the reaction solution can be controlled by adjusting the amount of alkaline solution added using a pH sensor or the like.

[0138] The second step may be performed for 10 hours or more, 15 hours or more, 20 hours or more, 23 hours or more, 25 hours or more, 26 hours or more, 28 hours or more, 30 hours or more, 33 hours or more, 35 hours or more, 100 hours or less, 80 hours or less, 60 hours or less, 50 hours or less, 48 ​​hours or less, 45 hours or less, 43 hours or less, or 41 hours or less. For example, the second step may be performed for 10 hours or more and 100 hours or less, 28 hours or more and 50 hours or less, 33 hours or more and 45 hours or less, or 35 hours or more and 41 hours or less. When the above range is satisfied, the positive electrode active material precursor particles grow smoothly, so that the BET specific surface area, pore area ratio, and particle size distribution of the positive electrode active material precursor can be appropriately controlled.

[0139]

[0140] The above stirring may be performed at a speed of 260 rpm to 400 rpm, 280 rpm to 380 rpm, or 300 rpm to 340 rpm. When the above ranges are satisfied, the manufactured positive electrode active material precursor may be uniformly formed and have an excellent particle size distribution.

[0141]

[0142] Meanwhile, when the reactor is full in the second stage, the supply of raw materials is stopped, stirring is stopped, the precursor particles in the reaction solution are allowed to settle, the supernatant is removed, and the supply of raw materials is resumed to proceed with the reaction. By performing the process of removing the supernatant in the reactor as described above, sufficient reaction time required for the growth of the positive electrode active material precursor particles can be secured, thereby increasing precursor production. The above process can be repeated two or more times.

[0143]

[0144] When the positive electrode active material precursor particles are sufficiently grown through the above process, the precursor particles can be separated from the reaction solution, washed, and then dried to obtain positive electrode active material precursor particles.

[0145]

[0146] positive electrode active material

[0147] The cathode active material precursor according to the present invention manufactured as described above can be mixed with a lithium raw material and then calcined to manufacture a cathode active material.

[0148] The above lithium raw material can be used without particular limitation as long as it is a compound containing a lithium source, and specifically, at least one selected from the group consisting of lithium carbonate (Li2CO3), lithium hydroxide (LiOHH2O), LiNO3, CH3COOLi, and Li2(COO)2 can be used.

[0149] The above-described positive electrode active material precursor and lithium raw material may be mixed so that the molar ratio of lithium (Li):transition metal (Me) contained in the positive electrode active material precursor is 1:1 to 1.2:1, 1:1 to 1.1:1, or 1:1 to 1.05:1. When the molar ratio of the positive electrode active material precursor and the lithium raw material satisfies the above range, the capacity of the positive electrode active material produced may be excellent, and the sintering may proceed smoothly so that the crystal structure of the positive electrode active material may be stably formed.

[0150] Additionally, if necessary, doping element M may be added during the firing. 1 The containing material can be additionally mixed. The above doping element M 1 For example, it may be at least one selected from the group consisting of Al, Ba, Ca, Zr, Ti, Mg, Ta, Nb and Mo, or it may be Al. The doping element M 1 The raw material containing the doping element M 1It may be at least one selected from the group consisting of acetate, sulfate, sulfide, hydroxide, oxide or oxyhydroxide, but is not limited thereto.

[0151] The above-mentioned sintering may be performed at 600°C to 950°C, 650°C to 900°C, 680°C to 850°C, 700°C to 800°C, or 720°C to 760°C. The positive electrode active material of the present invention can reduce defects and strain in the positive electrode active material structure by being sintered in the above temperature range. In particular, since the positive electrode active material of the present invention is manufactured using a positive electrode active material precursor in which the BET specific surface area, SPAN, and pore area ratio are controlled within specific ranges, even if the positive electrode active material including at least one of conventional single particles and pseudo-single particles is sintered at a temperature slightly lower than the sintering temperature during manufacture of the positive electrode active material, the positive electrode active material including at least one of single particles and pseudo-single particles can be smoothly formed. Accordingly, it has the advantage of being able to significantly reduce defects and strain in the positive electrode active material structure due to the high sintering temperature, and the resistance and output characteristics of the positive electrode active material can be improved.

[0152] The above firing can be performed for 5 to 35 hours, 5 to 25 hours, 7 to 20 hours, or 8 to 12 hours.

[0153]

[0154] The cathode active material of the present invention comprises at least one of a single particle composed of a single nodule or a pseudo-single particle composed of a composite of 30 or fewer nodules. Accordingly, the cathode active material of the present invention is less likely to break or crack particles due to rolling during electrode manufacturing, and thus less likely to generate gases or deteriorate the cathode active material due to side reactions with the electrolyte, thereby achieving excellent high-temperature lifespan characteristics.

[0155]

[0156] The positive electrode active material of the present invention may contain the single particles or the pseudo-single particles in an amount of 90 wt% to 100 wt%, 92 wt% to 100 wt%, 94 wt% to 100 wt%, or 100 wt% based on the total weight of the positive electrode active material. In this case, side reactions with the electrolyte due to fine particles generated from secondary particles during electrode manufacturing and charge / discharge can be suppressed, thereby obtaining sufficient life characteristics.

[0157]

[0158] The positive electrode active material of the present invention may contain nickel in an amount of 50 mol% or more, 52 mol% or more, 55 mol% or more, 57 mol% or more, 60 mol% or more, 99 mol% or less, 90 mol% or less, 85 mol% or less, 80 mol% or less, 75 mol% or less, 72 mol% or less, 70 mol% or less, 67 mol% or less, 65 mol% or less, 62 mol% or less, or 60 mol% or less of all metals excluding lithium. For example, the positive electrode active material of the present invention may contain nickel in an amount of 50 mol% or more, 50 mol% or more and 80 mol% or less, 50 mol% or more and 70 mol% or less, 55 mol% or more and 65 mol% or less, or 57 mol% to 62 mol% or less of all metals excluding lithium. When the above range is satisfied, excellent capacity can be realized. In particular, when the positive electrode active material contains nickel in an amount of 50 mol% or more and 80 mol% or less among all metals excluding lithium, it has the advantage of having excellent capacity characteristics and excellent structural stability.

[0159]

[0160] The cathode active material of the present invention may contain cobalt in an amount of 1 mol% or more, 3 mol% or more, 5 mol% or more, 7 mol% or more, 10 mol% or more, 20 mol% or less, 17 mol% or less, 15 mol% or less, 13 mol% or less, or 10 mol% or less of all metals excluding lithium. For example, the cathode active material of the present invention may contain cobalt in an amount of 20 mol% or less, 1 mol% or more and 17 mol% or less, 5 mol% or more and 15 mol% or less, or 7 mol% or more and 13 mol% or less of all metals excluding lithium. When the above range is satisfied, a cost advantage can be achieved by containing a relatively small amount of cobalt, while a certain level of output characteristics can be secured.

[0161]

[0162] The positive electrode active material of the present invention may contain manganese in an amount of 1 mol% or more, 5 mol% or more, 10 mol% or more, 15 mol% or more, 20 mol% or more, 25 mol% or more, 30 mol% or more, 40 mol% or less, 38 mol% or less, 37 mol% or less, 35 mol% or less, 33 mol% or less, 32 mol% or less, or 30 mol% or less of all metals excluding lithium. For example, the positive electrode active material of the present invention may contain manganese in an amount of 40 mol% or less, 1 mol% or more and 38 mol% or less, 10 mol% or more and 37 mol% or less, 20 mol% or more and 33 mol% or less, or 25 mol% or more and 32 mol% or less of all metals excluding lithium. When the above range is satisfied, the structural stability of the positive electrode active material may be excellent.

[0163]

[0164] The positive electrode active material of the present invention may include a doping element. The doping element may be at least one selected from the group consisting of Al, Ba, Ca, Zr, Ti, Mg, Ta, Nb, and Mo, or may be Al.

[0165] The cathode active material of the present invention may contain the doping element in an amount of 0.1 mol% or more, 0.5 mol% or more, 1 mol% or more, 1.5 mol% or more, 10 mol% or less, 8 mol% or less, 5 mol% or less, 3 mol% or less, or 2 mol% or less, of the total metal excluding lithium. When the above range is satisfied, the reactivity during firing can be improved, and the structural stability and output characteristics can be improved while maintaining the energy density of the cathode active material.

[0166]

[0167] The cathode active material of the present invention may include a lithium nickel-based oxide containing nickel, cobalt, and manganese. Specifically, the cathode active material of the present invention may include a lithium nickel-based oxide containing nickel, cobalt, manganese, and the above doping elements.

[0168]

[0169] The positive electrode active material of the present invention may have a composition represented by the following chemical formula 4.

[0170] [Chemical Formula 4] Li a Ni b Co c Mn d M 1 e O2

[0171] In the above chemical formula 4, M 1 It may be at least one selected from the group consisting of Al, Ba, Ca, Zr, Ti, Mg, Ta, Nb, W, Y and Mo.

[0172] The above a represents the molar ratio of lithium in the positive electrode active material particles, and may be 0.80≤a≤1.5, 0.9≤a≤1.2, 0.95≤a≤1.08, or 1≤a≤1.08.

[0173] The above b represents the molar ratio of nickel among the metal elements excluding lithium in the positive electrode active material particles, and may be 0.5≤b<1.0, 0.5≤b≤0.8, 0.5≤b≤0.7, 0.55≤b≤0.65, or 0.57≤b≤0.62. When the nickel content satisfies the above range, high-capacity characteristics and structural stability can be realized.

[0174] The above c represents the molar ratio of cobalt among the metal elements excluding lithium in the positive electrode active material particles, and is 0. <c≤0.2, 0.01≤c≤0.17, 0.05≤c≤0.15, 또는 0.07≤c≤0.13일 수 있다.

[0175] The above d represents the molar ratio of Mn among the metal elements excluding lithium in the positive electrode active material particles, and is 0. <d≤0.4, 0.01≤d≤0.38, 0.05≤d≤0.37, 0.1≤d≤0.35, 0.2≤d≤0.33, 또는 0.25≤d≤0.32일 수 있다.

[0176] The above e is M among the metal elements excluding lithium in the positive electrode active material particles. 1 It represents the molar ratio, and can be 0≤e≤0.10, or 0≤e≤0.05.

[0177]

[0178] The positive electrode active material of the present invention may have a single crystallinity of 2.7 or more, as defined by the following formula (A). The single crystallinity may function as a parameter indicating the degree of grain growth in the positive electrode active material.

[0179] Formula (A): Single crystallinity =

[0180] In the above formula (A), R iis the radius of the i-th grain measured when an electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode cross-section is analyzed by backscatter electron diffraction (EBSD). Although the value is measured in μm, the value substituted into the above formula (A) is a unitless number that does not include a unit, and n is the total number of grains measured through the backscatter electron diffraction (EBSD) analysis. The n may be 200 to 500.

[0181] Specifically, the positive electrode active material of the present invention may have a single crystallinity of 2.7 or more, 2.8 or more, 2.9 or more, 3.0 or more, 3.1 or more, 3.2 or more, 5.0 or less, 4.5 or less, 4.0 or less, 3.8 or less, 3.7 or less, or 3.6 or less. For example, the positive electrode active material of the present invention may have a single crystallinity of 2.7 or more, 2.8 or more, 3.2 or more, 3.2 or more and 5.0 or less, 3.2 or more and 4.5 or less, 3.2 or more and 4.0 or less, or 3.2 or more and 3.6 or less. When the single crystallinity value of the positive electrode active material satisfies the above range, the grains in the positive electrode active material grow sufficiently, so that the particle strength is superior to that of conventional secondary particle-shaped oxides, so that particle breakage can be reduced during rolling, and structural stability can be excellent. Accordingly, the energy density per unit volume can be excellent and the high temperature performance can be excellent.

[0182]

[0183] The cathode active material of the present invention may have a single particle size of 0.65 or more, as defined by the following formula (B). The single particle size is defined by the single crystallinity of the cathode active material, where the average particle diameter D 50It is a value divided by , and represents the degree of grain growth compared to the average particle size of the positive electrode active material. A smaller degree of single particle size means that the positive electrode active material particles are composed of a relatively large number of grains, and a larger degree of single particle size means that the positive electrode active material particles are composed of a relatively small number of grains.

[0184] Formula (B): Single particle magnetization =

[0185] In the above formula (B), R i is the radius of the i-th grain measured when the electrode cross-section is analyzed by backscatter electron diffraction (EBSD) after ion milling the electrode manufactured by applying the above positive electrode active material, and although it is a value measured in μm, the value substituted into the above formula (B) is a unitless number that does not include a unit, and the above n is the total number of grains measured through the above backscatter electron diffraction (EBSD) analysis and is 200 to 500. In addition, in the above formula (B), D 50 D of the above positive electrode active material 50 , and the value measured in ㎛ units or the value substituted into the above formula (B) is a unitless number that does not include a unit.

[0186] Specifically, the positive electrode active material of the present invention may have a single particle size distribution defined by the above formula (B) of 0.65 or more, 0.67 or more, 0.7 or more, 0.72 or more, 0.75 or more, 0.77 or more, 0.79 or more, 0.8 or more, 0.82 or more, 1.1 or less, 1.05 or less, 1 or less, 0.98 or less, 0.95 or less, or 0.92 or less. For example, the positive electrode active material of the present invention may have a single particle size distribution of 0.65 or more, 0.75 or more, 0.8 or more, or 0.82 to 0.92. When the single particle size distribution of the positive electrode active material satisfies the above range, the number of crystal grain boundaries may be relatively small, so that the particle strength may be excellent, and the specific surface area may be small, so that electrolyte side reactions and structural collapse of the positive electrode active material may be reduced. Accordingly, the cathode including the cathode active material has excellent energy density per unit volume due to less particle breakage during cathode rolling, and has excellent high-voltage and high-temperature performance.

[0187]

[0188] Average particle diameter D of the positive electrode active material of the present invention 50 The average particle size of the positive electrode active material of the present invention may be 1 ㎛ or more, 1.5 ㎛ or more, 2 ㎛ or more, more than 2 ㎛, 2.5 ㎛ or more, 3 ㎛ or more, 3.4 ㎛ or more, 3.6 ㎛ or more, 3.7 ㎛ or more, 3.8 ㎛ or more, 3.85 ㎛ or more, 6 ㎛ or less, 5.5 ㎛ or less, 5 ㎛ or less, 4.5 ㎛ or less, 4.1 ㎛ or less, 4 ㎛ or less, 3.95 ㎛ or less, or 3.92 ㎛ or less. For example, the average particle size D of the positive electrode active material of the present invention 50 The average particle size of the positive electrode active material of the present invention may be 1 ㎛ or more and 6 ㎛ or less, 1 ㎛ or more and 5 ㎛ or less, 2 ㎛ or more and 5 ㎛ or less, 3 ㎛ or more and 4.5 ㎛ or less, 3.7 ㎛ or more and 4.1 ㎛ or less, or 3.8 ㎛ or more and 3.92 ㎛ or less. When the average particle size of the positive electrode active material of the present invention satisfies the above range, the lithium ion diffusivity and electrical conductivity of the positive electrode active material may be improved, so that the output characteristics may be excellent, and the structural stability may be excellent.

[0189]

[0190] The average particle diameter (D) of the nodules in the positive electrode active material of the present invention n ) may be 1 ㎛ to 6 ㎛, 1 ㎛ to 5 ㎛, 1 to 4 ㎛ 1.5 to 3.0 ㎛, or 1.7 to 2.4 ㎛. When the above range is satisfied, the particle strength and high-temperature life characteristics of the positive electrode active material may be excellent.

[0191]

[0192] The I(003) / I(104) of the positive electrode active material of the present invention may be 1.24 or more, 1.25 or more, 1.26 or more, 1.27 or more, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.35 or less, or 1.31 or less. For example, the I(003) / I(104) of the positive electrode active material of the present invention may be 1.24 or more, 1.25 or more, 1.27 or more, 1.27 or more and 1.8 or less, 1.27 or more and 1.5 or less, or 1.27 or more and 1.31 or less. The above I(003) / I(104) refers to the ratio of the peak intensity I(003) of the (003) plane to the peak intensity I(104) of the (104) plane obtained by analyzing the positive electrode active material by "X-ray diffraction analysis (XRD)". The I(003) / I(104) value of the positive electrode active material can represent the crystalline characteristics of the layered structure, and when it satisfies the above range, the layered structure of the positive electrode active material is well formed, so that there is little cation mixing between lithium ions and nickel ions, and the electrochemical characteristics of the positive electrode active material are excellent.

[0193]

[0194] The positive electrode active material of the present invention may have a nickel disorder of more than 0% and less than 5%, 1% to 4%, or 1% to 3%. When the above range is satisfied, the structural stability of the positive electrode active material is secured, thereby reducing resistance and alleviating deterioration in lifespan.

[0195]

[0196] anode

[0197] The positive electrode according to the present invention comprises the positive electrode active material of the present invention described above. Specifically, the positive electrode comprises a positive electrode current collector, and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer may include a conductive material and a binder along with the positive electrode active material of the present invention. Since the positive electrode active material has been described above, a detailed description thereof will be omitted, and only the remaining components will be described in detail below.

[0198]

[0199] The positive electrode current collector of the present invention may include a highly conductive metal, and is not particularly limited as long as it is a metal to which the positive electrode active material layer can be easily adhered, but is not reactive in the voltage range of the battery. The positive electrode current collector may be made of, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 μm, and fine unevenness may be formed on the surface of the current collector to increase the adhesion of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0200]

[0201] The positive electrode active material layer of the present invention may optionally include a conductive material and a binder, together with the positive electrode active material, as needed.

[0202] At this time, the positive electrode active material may be included in an amount of 80 to 99 wt%, 85 to 98.5 wt%, or 90 to 98 wt% based on the total weight of the positive electrode active material layer, and when included in the above content range, it may exhibit excellent capacity characteristics.

[0203]

[0204] The conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One of these may be used alone, or a mixture of two or more may be used. The conductive material may be included in an amount of 0.1 to 15 wt%, 1 to 10 wt%, or 1.5 to 4 wt% based on the total weight of the positive electrode active material layer.

[0205]

[0206] The above binder serves to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylalcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, polyacrylic acid, and polymers in which hydrogens of these are substituted with Li, Na, or Ca, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. The above binder may be included in an amount of 0.1 to 15 wt%, 1 to 10 wt%, or 1.5 to 4 wt% based on the total weight of the positive electrode active material layer.

[0207]

[0208] The above positive electrode can be manufactured according to a conventional positive electrode manufacturing method. Specifically, a positive electrode active material can be prepared, and optionally, a binder, a conductive agent, and a dispersant can be dissolved or dispersed in a solvent to prepare a composition for forming a positive electrode active material layer. The composition for forming a positive electrode active material layer can be applied, dried, and rolled to manufacture the positive electrode.

[0209] The solvent may be a solvent generally used in the relevant technical field, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethyl formamide (DMF), acetone, or water. One of these may be used alone or a mixture of two or more thereof may be used. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, binder, and dispersant in consideration of the coating thickness and manufacturing yield of the slurry, and to have a viscosity that can exhibit excellent thickness uniformity when applied thereafter for manufacturing the positive electrode.

[0210]

[0211] Additionally, in another method, the positive electrode may be manufactured by casting the composition for forming the positive electrode active material layer on a separate support, and then laminating the resulting film on a positive electrode current collector by peeling it off from the support.

[0212]

[0213] electrochemical devices

[0214] Next, an electrochemical device according to the present invention will be described. The electrochemical device according to the present invention includes the anode of the present invention described above. Specifically, the electrochemical device may be a battery, a capacitor, or the like, and more specifically, a lithium secondary battery.

[0215] The lithium secondary battery specifically includes a positive electrode, a negative electrode positioned opposite the positive electrode, and a separator and electrolyte interposed between the positive electrode and the negative electrode. Since the positive electrode is the same as described above, a detailed description thereof will be omitted, and only the remaining components will be specifically described below.

[0216] In addition, the lithium secondary battery may optionally further include a battery container that houses the electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member that seals the battery container.

[0217]

[0218] In the above lithium secondary battery, the negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector.

[0219] The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 ㎛ to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0220]

[0221] The above negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material.

[0222] As the 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 alloy, Sn alloy, or Al alloy; SiO β(0 < β < 2), metal oxides capable of doping and dedoping lithium, such as SnO2, vanadium oxide, and lithium vanadium oxide; or composites containing the above metallic compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and any one or a mixture of two or more of these may be used. In addition, a metallic lithium thin film may be used as the negative electrode active material. In addition, both low-crystalline carbon and high-crystalline carbon may be used as the carbonaceous material. Representative examples of low-crystalline carbon include soft carbon and hard carbon, and representative examples of high-crystalline carbon include natural graphite or artificial graphite in the form of amorphous, plate-like, flaky, spherical, or fibers, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch derived cokes.

[0223] The above negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode active material layer.

[0224]

[0225] The above binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0226] The conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be added in an amount of 10 wt% or less, preferably 5 wt% or less, based on the total weight of the negative electrode active material layer. The conductive agent is not particularly limited as long as it has conductivity and does not cause a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber or metal fiber; 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; and conductive materials such as polyphenylene derivatives.

[0227]

[0228] The negative electrode active material layer may be manufactured by applying and drying a composition for forming a negative electrode active material layer prepared by dissolving or dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent, on a negative electrode current collector, or by casting the composition for forming a negative electrode active material layer on a separate support, and then laminating the film obtained by peeling it off from the support on a negative electrode current collector.

[0229]

[0230] Meanwhile, in the lithium secondary battery, the separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. Any separator commonly used in lithium secondary batteries can be used without any particular restrictions, and in particular, one having low resistance to ion movement of the electrolyte and excellent electrolyte moisture retention capacity is preferable. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0231]

[0232] In addition, the electrolyte used in the present invention may include, but is not limited to, 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. that can be used in the manufacture of a lithium secondary battery.

[0233] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0234] The organic solvent may be used without any particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R represents a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable.

[0235]

[0236] The above lithium salt can be used without any special limitation as long as it is a compound that can provide lithium ions used in a lithium secondary battery. Specifically, 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 - At least one selected from the group consisting of, and the lithium salt is LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2) 2. LiCl, LiI, or LiB(C2O4)2 can be used. It is recommended that the concentration of the lithium salt be within the range of 0.1 to 2.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively.

[0237]

[0238] In addition to the electrolyte components, the electrolyte may further include one or more additives, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 5 wt% based on the total weight of the electrolyte.

[0239]

[0240] As described above, the electrochemical device including the positive electrode according to the present invention stably exhibits excellent discharge capacity, output characteristics, and life characteristics, and is therefore useful in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs).

[0241] Accordingly, according to another embodiment of the present invention, a battery module including the electrochemical device as a unit cell and a battery pack including the same are provided.

[0242] The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0243] There is no particular limitation on the external shape of the electrochemical device of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape.

[0244] The electrochemical device according to the present invention can be used not only in a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells.

[0245] Examples of the above medium and large devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems.

[0246]

[0247] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0248]

[0249] Example

[0250] Example 1

[0251] (Step 1) NiSO4, CoSO4, and MnSO4 were dissolved in ion-exchanged water in an amount such that the molar ratio of nickel: cobalt: manganese was 6:1:3 to prepare a 2.0 M transition metal-containing solution. 4 L of deionized water was added to a 10 L batch reactor, and N2 gas was purged into the reactor at a rate of 2 L / min to remove dissolved oxygen in the water and create a non-oxidizing atmosphere. Then, 390 ml of 9 wt% ammonia water and 8.6 ml of 25 wt% sodium hydroxide aqueous solution were added, and the reactor temperature was increased while stirring at 300 rpm.

[0252] When the temperature of the solution inside the reactor reaches 70°C, the transition metal-containing solution is quantitatively injected at a flow rate of 400 ml / hr and 9 wt% ammonia water is quantitatively injected at a flow rate of 10 ml / hr for 5 hours to form a cathode active material precursor nucleus. At this time, a sodium hydroxide aqueous solution is injected using a pH peristaltic pump to maintain the pH of the reaction solution at 11.9.

[0253] (Step 2) After 5 hours, when the positive electrode active material precursor nucleus was formed, the flow rate of the transition metal-containing solution was supplied at 700 ml / hr, the flow rate of 9 wt% ammonia water was supplied at 10 ml / hr, and the mixture was stirred at a speed of 340 rpm. A sodium hydroxide aqueous solution was injected using a pH peristaltic pump to maintain the pH of the reaction solution at 11.6, and the coprecipitation reaction was performed.

[0254] When the volume of the reaction solution reached 10 L, the solvent in which the reaction was completed was discharged outside the reactor through a filter located inside the reactor, and the average particle diameter of the precursor particles D 50 The reaction was terminated when it reached 3.5 μm. The total reaction time was 41 hours.

[0255] After the positive electrode active material precursor particles were completely grown, the positive electrode active material precursor particles were separated from the reaction solution, washed to remove impurities, dried in a 140°C drying oven for 12 hours, and then sieved to prepare a positive electrode active material precursor.

[0256]

[0257] Example 2

[0258] (Step 1) The flow rate of the transition metal-containing solution was reduced to 350 ml / hr, the ammonia water with a concentration of 9 wt% was reduced to 6 ml / hr, and quantitatively injected for 11 hours; (Step 2) The stirring speed was reduced to 300 rpm, the pH of the reaction solution was maintained at 11.4, and the total reaction time was 35 hours. A positive electrode active material precursor was manufactured in the same manner as in Example 1, except that

[0259]

[0260] Example 3

[0261] (Step 2) A positive electrode active material precursor was manufactured in the same manner as in Example 1, except that the stirring speed was reduced to 300 rpm, the pH of the reaction solution was reduced to 11.4, and the total reaction time was 29 hours.

[0262]

[0263] Example 4

[0264] (Step 1) The flow rate of the transition metal-containing solution was reduced to 360 mL / hr, the flow rate of the 9 wt% ammonia solution was reduced to 8 mL / hr, and quantitative injection was performed for 7 hours. (Step 2) The flow rate of the transition metal-containing solution was supplied to 750 mL / hr, the flow rate of the 9 wt% ammonia solution was supplied to 11 mL / hr, the stirring speed was reduced to 300 rpm, and the average particle diameter of the precursor particles was D. 50 A positive electrode active material precursor was manufactured in the same manner as Example 1, except that the reaction was terminated when it reached 3.2 μm and the total reaction time was 32 hours.

[0265]

[0266] Comparative Example 1

[0267] (Step 2) A positive electrode active material precursor was manufactured in the same manner as in Example 1, except that the supply rate of the transition metal-containing solution was increased to 800 ml / hr, the pH of the reaction solution was reduced to 11.2, and the total reaction time was 22 hours.

[0268]

[0269] Comparative Example 2

[0270] (Step 2) A positive electrode active material precursor was manufactured in the same manner as Example 1, except that the stirring speed was reduced to 250 rpm, the pH of the reaction solution was reduced to 11.3, and the total reaction time was 25 hours.

[0271]

[0272] Comparative Example 3

[0273] (Step 1) The supply rate of 9 wt% ammonia water was increased to 12 ml / hr, the pH was reduced to 11.8, and (Step 2) the stirring speed was reduced to 300 rpm, and the total reaction time was 27 hours. A positive electrode active material precursor was manufactured in the same manner as in Example 1, except that.

[0274]

[0275] Comparative Example 4

[0276] (Step 1) The supply rate of the transition metal-containing solution was reduced to 340 ml / hr, the supply rate of the 9 wt% ammonia water was reduced to 5.8 ml / hr, and the reaction was carried out by quantitative injection for 14 hours; (Step 2) The pH of the reaction solution was increased to 11.8, the supply rate of the 9 wt% ammonia water was increased to 12 ml / hr, and the total reaction time was 52 hours, except that a positive electrode active material precursor was manufactured in the same manner as in Example 1.

[0277]

[0278] Experimental Example 1 - Evaluation of Precursor Powder Characteristics

[0279] Average particle diameter D of the positive electrode active material precursors manufactured in Examples 1 to 4 and Comparative Examples 1 to 4 50 , BET surface area and pore area ratio (PAR) were measured using the following methods. The measurement results are shown in Table 1 below.

[0280] (1) Average particle diameter D 50 : The volume-based cumulative particle size distribution was measured using a particle size distribution measuring device (Microtrac S3500, Microtrac).

[0281] (2) BET specific surface area: The specific surface area was measured by the BET method using BELSORP-mini II from BEL Japan, calculated from the nitrogen gas adsorption amount at liquid nitrogen temperature (77 K).

[0282] (3) Pore Area Ratio (PAR): After impregnating and curing the positive electrode active material precursor into the resin, the particles of the positive electrode active material precursor are cut using a focused ion beam (FIB) so that a cross-section can be observed. Thereafter, a scanning electron microscope (SEM) is used to obtain SEM cross-sectional images of a plurality of positive electrode active material precursor particles. The pores of each positive electrode active material precursor particle are shaded and the dense parts of each positive electrode active material precursor particle are white in each obtained SEM cross-sectional image using image analysis software such as WinRoof 6.1.1. The ratio (%) is calculated as [shaded area / (shaded area + white area) × 100] for any 20 or more positive electrode active material precursor particles, and the pore area ratio (PAR) is obtained by obtaining the arithmetic mean value.

[0283] D 50 [Unit: ㎛]BET [Unit: m 2 / g]Pore area ratio (PAR) (%)Example 13.4423.428.8Example 23.4220.124.3Example 33.4418.418.1Example 43.1427.916.4Comparative Example 13.3511.019.7Comparative Example 23.1616.222.2Comparative Example 33.2316.98.5Comparative Example 43.1824.834.0

[0284] Experimental Example 2 - Precursor Particle Size Analysis

[0285] The positive electrode active material precursors of Examples 1 to 4 and Comparative Examples 1 to 4 were collected, and the volume-based cumulative particle size distribution of the precursor particles generated in the reaction solution was measured using a particle size distribution measuring device (Microtrac S3500, Microtrac Co.).

[0286] D measured in the above experimental example 1 50 Using the values ​​of the formula (C): SPAN = (D 90 -D 10 ) / D 50 The SPAN value defined as was calculated.

[0287] D 10 [Unit: ㎛]D 90 [Unit: ㎛] SPAN Example 12.42 4.07 0.480 Example 22.39 4.20 0.529 Example 32.41 4.30 0.549 Example 42.29 4.30.64 Comparative Example 12.40 4.28 0.561 Comparative Example 22.29 4.57 0.722 Comparative Example 32.44 4.29 0.573 Comparative Example 42.52 3.99 0.462

[0288] <Manufacturing of positive electrode active materials>

[0289] Each of the positive electrode active material precursors of Examples 1 to 4 and Comparative Examples 1 to 4 and LiOH and Al2O3 was mixed so that the molar ratio of (Ni+Co+Mn):Li:Al was 1.00:1.03:0.02, and then calcined at 740°C for 10 hours to manufacture positive electrode active materials using the positive electrode active material precursors of Examples 1 to 4 and Comparative Examples 1 to 4, respectively.

[0290]

[0291] Experimental Example 3 - Analysis of Cathode Active Material

[0292] (1) Single crystallinity

[0293] For each manufactured positive electrode active material, the value obtained by "backscatter electron diffraction (EBSD) analysis" was substituted into the following equation (A) to calculate the degree of single crystallinity. The results are shown in Table 3 below.

[0294] Formula (A): Single crystallinity =

[0295] In the above formula (A), R iis the radius of the i-th grain measured when an electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode cross-section is analyzed by backscatter electron diffraction (EBSD). Although the value is measured in μm, the value substituted into equation (A) is a unitless number that does not include a unit, and n is the total number of grains measured through backscatter electron diffraction (EBSD) analysis and is 200 to 500.

[0296] (2) I(003) / I104)

[0297] For each manufactured positive electrode active material, the ratio of the peak intensity I(003) of the (003) plane to the peak intensity I(104) of the (104) plane was measured by "X-ray diffraction analysis (XRD)". The results are shown in Table 3 below.

[0298] Specifically, the sample to be measured was fixed on the holder, and X-ray diffraction analysis was performed using a Bruker D8 Endeavor (light source: Cu Kα, λ=1.54Å) equipped with a LynxEye XE-T position sensitive detector, with a step size of 0.014 degrees and a total scan time of approximately 40 minutes over the FDS 0.5°, 2θ=10° to 90° region. Rietveld refinement was performed on the measured data considering the charge (+3 for metal ions at transition metal sites, +2 for Ni ions at Li sites) and cation mixing at each site. Instrumental broadening was considered using the Fundamental Parameter Approach (FPA) implemented in the Bruker TOPAS program, and the entire peaks in the measurement range were used for fitting. The peak shape was fitted using only the Lorentzian contribution as the FP (First Principle) among the peak types available in TOPAS, and strain was not considered at this time.

[0299] (3) Particle size analysis of positive electrode active material

[0300] Each manufactured positive electrode active material was sampled, and the volume-based cumulative particle size distribution of the positive electrode active material particles generated in the reaction solution was measured using a particle size distribution measuring device (Microtrac S3500, Microtrac).

[0301] D of the measured positive electrode active material 90 , D 50 , D 10 Using the values ​​of the formula (C): SPAN = (D 90 -D 10 ) / D 50The SPAN value defined as was calculated. The results are shown in Table 3 below.

[0302]

[0303] (4) Single particle magnetization

[0304] For each manufactured positive electrode active material, the value obtained by "backscatter electron diffraction (EBSD) analysis" was substituted into Equation (B) below to calculate the degree of single particle magnetization. The results are shown in Table 3 below.

[0305] Formula (B):

[0306] In the above formula (B), R i is the radius of the i-th grain measured when the electrode cross-section is analyzed by backscatter electron diffraction (EBSD) after ion milling the electrode manufactured by applying the above positive electrode active material, and although it is a value measured in μm, the value substituted into the above formula (B) is a unitless number that does not include a unit, and the above n is the total number of grains measured through the above backscatter electron diffraction (EBSD) analysis and is 200 to 500. In addition, in the above formula (B), D 50 D of the above positive electrode active material 50 , and the value measured in ㎛ units or the value substituted into the above formula (B) is a unitless number that does not include a unit.

[0307]

[0308] Single crystallinity I(003) / I(104) particle size analysis Single crystallinity D 50 (㎛)D 90 (㎛)D 10(㎛)SPANExample 13.61.313.926.781.851.260.92Example 23.21.273.896.381.71.200.82Example 33.11.293.956.511.751.210.78Example 42.71.243.646.511.351.420.74Comparative Example 12.41.233.946.781.791.270.61Comparative Example 22.11.184.127.211.541.380.51Comparative Example 32.61.224.187.141.851.270.62Comparative Example 41.91.073.796.141.451.240.50

[0309] <Lithium secondary battery manufacturing>

[0310] As described above, a positive electrode slurry was prepared by mixing the positive electrode active material prepared from each of the positive electrode active material precursors prepared in Examples 1 to 4 and Comparative Examples 1 to 4, carbon black as a conductive material, and polyvinylidene fluoride (PVDF) as a binder in a weight ratio of 95.0:2.5:2.5 in N-methyl-2-pyrrolidone (NMP). The positive electrode slurry was applied to one surface of an aluminum current collector, dried at 130°C, and then rolled to prepare a positive electrode.

[0311] A negative electrode slurry was prepared by mixing artificial graphite as a negative active material, carbon black as a conductive material, and a styrene butadiene rubber (SBR)-carboxymethyl cellulose (CMC) composite as a binder in a weight ratio of 95.5:1.0:3.5, and the slurry was applied to one side of a copper current collector, dried at 100°C, and then rolled to prepare a negative electrode.

[0312] An electrode assembly was manufactured by interposing a separator between the positive and negative electrodes, and then positioning it inside a battery case, and then injecting an electrolyte into the case to manufacture a lithium secondary battery. The electrolyte was an electrolyte in which 1 M LiPF6 was dissolved in a mixed organic solvent containing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 1:2.

[0313]

[0314] Experimental Example 4 - Output Characteristics

[0315] For each lithium secondary battery manufactured above, an activation (formation) process was performed, and then the battery was charged in CC-CV mode at 45°C at 0.5C (reference capacity 1.0C = 190mAh / g) to 4.4 V, and discharged in CC mode at 0.1C to 2.5 V. After charging under the same conditions, the current was changed to 2.0C C-rate to measure the discharge capacity, and then the output characteristics were calculated by calculating the discharge capacity of 2.0C compared to 0.1C. The calculated output characteristics (%) are shown in Table 4 below.

[0316]

[0317] Experimental Example 5 - High Temperature Life Characteristics

[0318] For each lithium secondary battery manufactured above, 200 cycles of charge-discharge were performed, in which one cycle was performed by charging at 0.33C in CC-CV mode at 45°C until 4.35 V, and discharging at a constant current of 0.33C until 2.5 V. The capacity retention rate was calculated by measuring the capacity after 200 cycles of charge-discharge compared to the capacity after 1 cycle of charge-discharge. The calculated capacity retention rate (%) is shown in Table 4.

[0319]

[0320] Output Characteristics (%) Capacity Retention Rate (%) Example 189.892 Example 290.191.8 Example 389.391.1 Example 489.788.7 Comparative Example 187.387.5 Comparative Example 286.183.6 Comparative Example 386.788.9 Comparative Example 489.481.3

[0321] As shown in Table 4 above, it was confirmed that the output characteristics and high-temperature life characteristics of the lithium secondary batteries including the positive electrode active materials of Examples 1 to 4 manufactured using the positive electrode active material precursor of the present invention were superior to those of the lithium secondary batteries of Comparative Examples 1 to 4.

Claims

A cathode active material comprising at least one of a single particle consisting of 1.1 nodule and a pseudo-single particle which is a composite of 30 or fewer nodules, A cathode active material having a crystallinity of 2.7 or higher, as defined by the following formula (A). Formula (A): Single crystallinity = In the above formula (A), R i is the radius of the i-th grain measured when the electrode cross-section is analyzed by backscatter electron diffraction (EBSD) after ion milling the electrode manufactured by applying the above positive electrode active material, and although it is a value measured in μm, the value substituted into the above formula (A) is a unitless number that does not include a unit. n is the total number of grains measured through the above backscatter electron diffraction (EBSD) analysis.

2. In paragraph 1, A cathode active material having a single crystallinity of 2.8 or higher.

3. In paragraph 1, A cathode active material having a crystallinity of 3.2 or higher.

4. In paragraph 1, A cathode active material having a single particle magnetization degree of 0.65 or more, as defined by the following formula (B). Formula (B): Single particle magnetization = In the above formula (B), R i is the radius of the i-th grain measured when the electrode cross-section is analyzed by backscatter electron diffraction (EBSD) after ion milling the electrode manufactured by applying the above positive electrode active material, and although it is a value measured in μm, the value substituted into the above formula (B) is a unitless number that does not include a unit. n is the total number of grains measured through the above backscatter electron diffraction (EBSD) analysis, D 50 D of the above positive electrode active material 50 , and the value measured in ㎛ units or the value substituted into the above formula (B) is a unitless number that does not include a unit.

5. In paragraph 4, A positive electrode active material having a single particle magnetization degree of 0.75 or more.

6. In paragraph 1, A cathode active material containing nickel in an amount of 50 mol% or more among all metals excluding lithium.

7. In paragraph 1, A positive electrode active material having an I(003) / I(104) of 1.24 or more.

8. A positive electrode comprising the positive electrode active material of paragraph 1.

9. An electrochemical device comprising the anode of paragraph 8.

10. BET surface area is 16m 2 / g is exceeded, SPAN, defined by the following formula (C), is less than or equal to 0.7, A cathode active material precursor having a pore area ratio (PAR) of 10% or more and 30% or less. Formula (C): SPAN = (D 90 -D 10 ) / D 50 In the above formula (C), D 90 refers to the particle size at the 90% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above-mentioned positive electrode active material precursor, D 50 means the particle size at the 50% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above-mentioned positive electrode active material precursor, D 10 refers to the particle size at the 10% point of the volume cumulative distribution according to the particle size measured by laser diffraction for the above-mentioned positive electrode active material precursor.

11. In paragraph 10, The above BET surface area is 18 m 2 / g or more than 27m 2 / g or less, positive electrode active material precursor.

12. In paragraph 10, The above BET surface area is 19 m 2 / g or more than 25m 2 / g or less, positive electrode active material precursor.

13. In paragraph 10, A positive electrode active material precursor having a SPAN of 0.20 or more and 0.60 or less.

14. In paragraph 10, A positive electrode active material precursor having a SPAN of 0.40 or more and 0.54 or less.

15. In paragraph 10, A cathode active material precursor having a pore area ratio (PAR) of 17% or more and 30% or less.

16. In paragraph 10, A cathode active material precursor having a pore area ratio (PAR) of 19% or more and 29% or less.

17. In paragraph 10, A cathode active material precursor containing nickel in an amount of 50 mol% or more among the total metals.

18. In paragraph 10, Average particle diameter D 50 A positive electrode active material precursor having a size of 2.0㎛ or more and 5.0㎛ or less.

19. A first step of forming a positive electrode active material precursor nucleus by conducting a co-precipitation reaction while supplying a transition metal-containing solution, an ammonium cation complex forming agent, and a basic solution to a reactor; and A second step of growing positive electrode active material precursor particles by supplying a transition metal-containing solution, an ammonium complex forming agent, and a basic solution to the reaction solution in which the positive electrode active material precursor nuclei are formed, thereby performing a co-precipitation reaction; In the above first step, the ammonium cation complex forming agent is supplied at a flow rate of 6 mL / hr or more and 11 mL / hr or less, A method for producing a positive electrode active material precursor, wherein the pH of the reaction solution in the above second step is 11.4 or higher.

20. In paragraph 19, A method for manufacturing a positive electrode active material precursor, wherein in the second step, the transition metal-containing solution is supplied at a flow rate of 730 mL / hr or less.

21. In paragraph 19, A method for manufacturing a positive electrode active material precursor, wherein the second step is performed for 33 hours or more.

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