Positive electrode material and method for manufacturing same

Abstract

The present invention relates to a positive electrode material comprising a single-particle positive electrode active material, and a method for manufacturing same. As a result of EPMA analysis, a high Mn concentration region is observed in the single-particle positive electrode active material.

Description

Cathode material and method for manufacturing the same

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0144119, filed October 25, 2023, the entire disclosure of which is incorporated herein by reference.

[0003]

[0004] [Technical Field]

[0005] The present invention relates to a cathode material and a method for manufacturing the same.

[0006] Lithium secondary batteries, which allow for repeated charging and discharging, are attracting attention as an alternative to fossil fuels. Lithium secondary batteries have been primarily used in traditional handheld devices such as cell phones, video cameras, and power tools. However, their applications are gradually expanding to include electric vehicles (EVs, HEVs, PHEVs), large-capacity energy storage systems (ESSs), and uninterruptible power supply systems (UPSs). A lithium secondary battery consists of an electrode assembly, which is a collection of unit cells each having a structure in which a positive and negative electrode plates, each coated with an active material on a current collector, are arranged with a separator between them, and an outer case, i.e., a battery case, that seals and encloses the electrode assembly together with an electrolyte.

[0007] Lithium composite transition metal oxides are used as positive active materials for lithium secondary batteries, and among these, lithium cobalt oxide of LiCoO2, lithium manganese oxide (such as LiMnO2 or LiMn2O4), lithium iron phosphate compound (LiFePO4), or LiNiO2 are mainly used. In addition, as a method to improve the low thermal stability while maintaining the excellent reversible capacity of LiNiO2, nickel manganese lithium composite metal oxides in which some of the nickel is replaced with manganese, which has excellent thermal stability, and NCM in which manganese and cobalt are replaced, or NCMA in which Al is added to NCM to improve the output and stability of the battery are used.

[0008] Previously, a method for synthesizing NCMA single-particle cathode active materials was proposed: mixing an NCM precursor synthesized via co-precipitation with an aluminum raw material and heat-treating it. However, this synthesis method entails precursor processing and washing / drying processes, which incur additional manufacturing costs and environmental concerns. Therefore, the development of a new cathode active material manufacturing method is urgently needed to enhance price competitiveness and comply with environmental regulations.

[0009] Meanwhile, existing cathode active material particles are polycrystalline multiparticle materials in the form of secondary particles formed by the aggregation of primary particles. When small primary particles aggregate to form physically distinguishable large particles, they are called secondary particles. Existing cathode active material particles have a large specific surface area and low particle strength. In particular, in this form, the contact area with the electrolyte is high, which leads to severe deterioration of thermal characteristics due to repeated charge / discharge cycles, and when cracks occur and new surfaces are exposed, gas generation due to side reactions is serious. Therefore, there has been a demand in the industry for single-particle cathode active materials.

[0010] [Prior Art Literature]

[0011] [Patent Document]

[0012] (Patent Document 0001) KR 10-1937926 B1

[0013] The problem to be solved by the present invention is to provide a cathode material with improved life characteristics and stability.

[0014] (1) The present invention provides a cathode material including a cathode active material in the form of a single particle, wherein when a cross-section of the cathode including the cathode material is measured by EPMA under conditions of an acceleration voltage of 15 kV and a probe current of 50 nA, a high Mn concentration region existing on the cross-section of the cathode active material is observed in the EPMA image, and the high Mn concentration region is a region having a Mn concentration % greater than or equal to a point where the maximum value (max) of the Mn concentration scale bar of the EPMA image is the Mn mol% value of the cathode active material analyzed by ICP (Inductive Coupled Plasma), and the minimum value (min) of the Mn concentration scale bar of the EPMA image is the Mn mol% of the cathode active material analyzed by ICP divided by 3 and rounded down to the first decimal place, based on the Mn concentration scale bar of the EPMA image, the maximum value (max) and the minimum value (min) are divided by 1:1.

[0015] (2) The present invention provides a cathode material in (1) above, wherein the high Mn concentration region has an area ratio of 1 / 100 or more compared to the cross-sectional area of ​​one cathode active material particle in which the high Mn concentration region is observed.

[0016] (3) The present invention provides a cathode material in (1) or (2) above, wherein the high Mn concentration region is distributed on the surface and / or inside of the cathode active material.

[0017] (4) The present invention provides a cathode material in any one of the above (1) to (3), wherein the high Mn concentration region is distributed inside the cathode active material.

[0018] (5) The present invention, in any one of the above (1) to (4), has an average particle diameter (D) of the positive electrode active material. 50 ) provides a cathode material having a diameter of 1 ㎛ or more and 15 ㎛ or less.

[0019] (6) The present invention provides a cathode material according to any one of (1) to (5), wherein the cathode active material comprises a lithium composite transition metal oxide represented by the following chemical formula 1.

[0020] [Chemical Formula 1]

[0021] Li w Ni x Co y Mn z M 1 1-x-y-z O2

[0022] In the above chemical formula 1, M 1 is at least one selected from the group consisting of B, F, Mg, Al, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd,

[0023] 0.8≤w≤1.2, 0.5≤x<1.0, 0≤y≤0.2, 0 <z≤0.4이다.

[0024] (7) The present invention provides a cathode material according to any one of (1) to (6), wherein the cathode active material comprises a lithium composite transition metal oxide represented by the following chemical formula 2.

[0025] [Chemical Formula 2]

[0026] Li a Ni b Co c Mn d Al e M2 f O2

[0027] In the above chemical formula 2, M 2 is at least one selected from the group consisting of B, F, Mg, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd,

[0028] 0.8≤a≤1.2, 0.5≤b<1.0, 0≤c≤0.2, 0 <d≤0.4, 0≤e≤0.1, 0≤f≤0.1, b+c+d+e+f = 1이다.

[0029] According to the present invention, the life characteristics and stability of the cathode material are improved.

[0030] Figure 1 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 1.

[0031] Figure 2 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 2.

[0032] Figure 3 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 3.

[0033] Figure 4 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 4.

[0034] Figure 5 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 5.

[0035] Figure 6 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 6.

[0036] Figure 7 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 7.

[0037] Figure 8 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 8.

[0038] Figure 9 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 9.

[0039] Figure 10 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 10.

[0040] Figure 11 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 11.

[0041] Figure 12 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 12.

[0042] Figure 13 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Example 13.

[0043] Figure 14 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Comparative Example 1.

[0044] Figure 15 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Comparative Example 2.

[0045] Figure 16 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Comparative Example 3.

[0046] Figure 17 is an EPMA measurement photograph of an electrode including a positive electrode active material manufactured in Comparative Example 4.

[0047] Hereinafter, the present invention will be described in more detail to help understand the present invention.

[0048] Terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0049] In the present invention, the term 'primary particle' means the smallest particle unit that can be distinguished as a single lump when observing the cross-section of a positive electrode active material through a scanning electron microscope (SEM), and may be composed of multiple crystal grains.

[0050] In the present invention, the term "secondary particle" refers to a secondary structure formed by the aggregation of multiple primary particles. The average particle diameter of the secondary particles can be measured using a particle size analyzer.

[0051] In the present invention, the term 'single particle form' may be used instead of the term 'single particle type', and means a form that is contrasted with a secondary particle form formed by agglomeration of hundreds of primary particles manufactured by a conventional method. In addition, the term 'single particle type positive electrode active material' or 'single particle type lithium transition metal oxide' in the present invention is a concept that is contrasted with a positive electrode active material in the form of secondary particles formed by agglomeration of hundreds of primary particles manufactured by a conventional method, and means a positive electrode active material or lithium transition metal active material composed of 1 to 100 or less particles, 1 to 80 or less particles, 1 to 60 or less particles, 1 to 40 or less particles, 1 to 20 or less particles, 1 to 10 or less particles, or 1 to 5 or less particles. The 'single particle' refers to the smallest particle unit recognized when the positive electrode active material is observed through a scanning electron microscope.

[0052] In the present invention, the term 'average particle diameter (D 50)' means the particle size at the 50% point of the volume cumulative distribution according to particle size. The above average particle size is calculated by dispersing the powder to be measured in a dispersion medium, introducing it into a commercially available laser diffraction particle size measuring device (e.g., S3500 from Microtrac), and measuring the difference in diffraction pattern according to particle size when the particles pass through the laser beam to calculate the particle size distribution, and calculating the particle diameter at the point where it becomes 50% of the volume cumulative distribution according to particle size in the measuring device, thereby obtaining D 50 can be measured.

[0053]

[0054] <Polar electrode>

[0055] The present invention provides a cathode material.

[0056] The cathode material of the present invention is a cathode material including a cathode active material in the form of a single particle, and when a cross-section of the cathode including the cathode material is measured by EPMA under conditions of an acceleration voltage of 15 kV and a probe current of 50 nA, a high Mn concentration region existing on the cross-section of the cathode active material is observed in the EPMA image, and the high Mn concentration region is a region having a Mn concentration% greater than or equal to a point where the maximum value (max) of the Mn concentration scale bar of the EPMA image is the Mn mol% value of the cathode active material analyzed by ICP (Inductive Coupled Plasma), and the minimum value (min) of the Mn concentration scale bar of the EPMA image is the Mn mol% of the cathode active material analyzed by ICP divided by 3 and rounded down to the first decimal place, based on the Mn concentration scale bar of the EPMA image, the maximum value (max) and the minimum value (min) are divided by 1:1.

[0057]

[0058] The inventors of the present invention have discovered that, by using the method for manufacturing a cathode material described below, when a high Mn concentration region exists inside a cathode active material in the form of a single particle, the life characteristics and stability are improved by exhibiting the same effect as when a portion of the surface or region of the cathode active material in the form of a single particle is coated or doped, thereby completing the present invention.

[0059]

[0060] According to one embodiment of the present invention, the high Mn concentration region does not mean a region in which the Mn concentration value is higher than a certain fixed concentration value regardless of the composition of the positive electrode active material, but rather means a region in which the Mn element is more densely packed inside the positive electrode active material in the form of a single particle than in the surrounding area by the positive electrode material manufacturing method described below, and thus the Mn concentration is relatively higher than in other surrounding areas. Specifically, the high Mn concentration region is identified by measuring a cross-section of an electrode including a positive electrode active material by EPMA, and when the maximum value (max) of the Mn concentration scale bar of the EPMA image is the Mn mol% value of the positive electrode active material analyzed by ICP (Inductive Coupled Plasma), and the minimum value (min) of the Mn concentration scale bar of the EPMA image is the Mn mol% of the positive electrode active material analyzed by ICP divided by 3, and the value rounded down to the first decimal place, the region can be defined as a region where the Mn concentration% is equal to or greater than the point where the maximum value (max) and the minimum value (min) are divided 1:1 based on the Mn concentration scale bar of the EPMA image.

[0061] In the present specification, dividing the maximum value (max) and the minimum value (min) into a:b means that the length from the maximum value (max) to the point of internal division : the length from the minimum value (min) to the point of internal division is a:b. According to one embodiment of the present invention, the high Mn concentration region may be defined as a region having a Mn concentration % greater than or equal to the point where the maximum value (max) and the minimum value (min) are divided into 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18, 1:1.2, 1:1.22, 1:1.24, 1:1.26, 1:1.28 or 1:1.3 based on the Mn concentration scale bar on the EPMA image. When the above-described range is satisfied, the life characteristics and stability can be improved by showing the same effect as coating a portion of the surface of the positive electrode active material in the form of a single particle or doping the internal region.

[0062] According to one embodiment of the present invention, ICP analysis can be performed using an inductively coupled plasma optical emission spectrometer (ICP-OES; PerkinElmer, Optima 8000DV).

[0063] According to one embodiment of the present invention, the maximum value (max) of the Mn concentration scale bar of the EPMA image may be the Mn mol% value of the positive active material analyzed by ICP, and the minimum value (min) of the Mn concentration scale bar of the EPMA image may be a value obtained by dividing the Mn mol% of the positive active material analyzed by ICP by 3 and truncating it to one decimal place. In this way, by specifying the maximum value (max) and the minimum value (min) of the Mn concentration scale bar of the EPMA image, the Mn concentration distributed in the cross-section of the positive active material on the EPMA image can be easily measured, and a high Mn concentration region within the positive active material can be observed regardless of the composition of the positive active material. Specifically, since the maximum value (max) and the minimum value (min) of the Mn concentration scale bar in the EPMA image according to one embodiment of the present invention may vary depending on the Mn composition of the positive active material, a high Mn concentration region within the positive active material can be observed regardless of the composition of the positive active material.

[0064] If the maximum (max) and minimum (min) values ​​of the Mn concentration scale bar are fixed regardless of the composition of the positive electrode active material, it may be difficult to observe a high Mn concentration region as the Mn composition of the positive electrode active material becomes leaner. For example, when the maximum (max) value of the Mn concentration scale bar is fixed to 15% concentration and the minimum (min) value is fixed to 0% concentration and an EPMA image is obtained, in the case of a positive electrode active material having a composition in which the mol% of Mn is 1 mol% or less, only a portion of the Mn concentration scale bar is observed, and thus the high Mn concentration region may not be observed. The present invention adjusts the maximum (max) and minimum (min) values ​​of the Mn concentration scale bar on the EPMA image according to the composition of the positive electrode active material, thereby making it possible to observe the relative Mn concentration distribution within the positive electrode active material regardless of the composition of the positive electrode active material.

[0065] According to one embodiment of the present invention, the area of ​​the high Mn concentration region may have an area ratio of 1 / 100 or more compared to the cross-sectional area of ​​one positive electrode active material particle in which the high Mn concentration region is observed, and for specific examples, may have an area ratio of 1 / 90 or more, 1 / 70 or more, 1 / 50 or more, 1 / 30 or more, or 1 / 10 or more.

[0066] According to one embodiment of the present invention, the Mn concentration within the region defined as the high Mn concentration region may have a Mn concentration % greater than or equal to a point where the maximum value (max) and minimum value (min) of the scale bar of the EPMA image adjusted according to the composition of the positive electrode active material as described above are divided 1:1.

[0067]

[0068] According to one embodiment of the present invention, the high Mn concentration region can be observed as one or more regions on the cross-section of the positive electrode active material, and when the cross-section of the positive electrode made of a positive electrode material including a plurality of positive electrode active materials is analyzed by EPMA under the conditions described above, the regions can be observed to be dispersed on the EPMA image.

[0069] According to one embodiment of the present invention, in addition to the high Mn concentration region, a region having a Mn concentration % less than a point where the maximum value (max) and minimum value (min) of the scale bar of the EPMA image adjusted according to the composition of the positive electrode active material as described above are divided into 1:1 can be further observed on the cross-section of the positive electrode active material.

[0070] According to one embodiment of the present invention, when a plurality of high Mn concentration regions are observed, the regions can be distinguished by the presence of a region having a Mn concentration % less than a point where the maximum value (max) and minimum value (min) of the scale bar of the EPMA image adjusted according to the composition of the positive electrode active material as described above are divided 1:1 between each high Mn concentration region.

[0071] According to one embodiment of the present invention, the high Mn concentration region may be defined only between positive electrode active materials having the same composition and crystal structure. For example, in the case of a positive electrode material in which different types of positive electrode active materials having different compositions and / or crystal structures are blended, the high Mn concentration region may be defined only in relation to a single type of positive electrode active material having the same composition and crystal structure within the positive electrode material.

[0072] According to one embodiment of the present invention, a high Mn concentration region formed in a single particle type positive electrode active material by the positive electrode material manufacturing method described below is not limited to the surface of the positive electrode active material but exists inside the positive electrode active material, and the high Mn concentration region is not limited to the surface of the positive electrode active material but can be distributed inside the positive electrode active material.

[0073] Specifically, the fact that the positive electrode active material according to one embodiment of the present invention includes the high Mn concentration region may include cases where the high Mn concentration region is distributed on the surface of the positive electrode active material, cases where the high Mn concentration region is distributed inside the positive electrode active material, and cases where the high Mn concentration region is distributed on the surface and inside the positive electrode active material.

[0074]

[0075] According to one embodiment of the present invention, the positive electrode active material may include a lithium composite transition metal oxide represented by the following chemical formula 1.

[0076] [Chemical Formula 1]

[0077] Li w Ni x Co y Mn z M 1 1-x-y-z O2

[0078] In the above chemical formula 1, M 1is at least one selected from the group consisting of B, F, Mg, Al, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd,

[0079] 0.8≤w≤1.2, 0.5≤x<1.0, 0≤y≤0.2, 0 <z≤0.4이다.

[0080]

[0081] In addition, specifically, the lithium composite transition metal oxide may be a lithium composite transition metal oxide represented by the following chemical formula 2.

[0082] [Chemical Formula 2]

[0083] Li a Ni b Co c Mn d Al e M 2 f O2

[0084] In the above chemical formula 2, M 2 is at least one selected from the group consisting of B, F, Mg, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd,

[0085] 0.8≤a≤1.2, 0.5≤b<1.0, 0≤c≤0.2, 0 <d≤0.4, 0≤e≤0.1, 0≤f≤0.1, b+c+d+e+f = 1이다.

[0086] The above a represents the molar ratio of lithium in the lithium composite transition metal oxide, and may be 0.8 or more and 1.2 or less, and as specific examples, may be 0.84 or more, 0.88 or more, 0.92 or more, 0.96 or more, or 1.00 or more, and may also be 1.18 or less, 1.16 or less, 1.14 or less, 1.12 or less, 1.10 or less, 1.08 or less, 1.06 or less, or 1.04 or less.

[0087] The above b represents the molar ratio of nickel in the lithium composite transition metal oxide, and may be 0.5 or more and less than 1.0, and as a specific example, may be 0.55 or more, 0.60 or more, 0.65 or more, 0.70 or more, or 0.75 or more, and may also be 0.98 or less, 0.96 or less, 0.94 or less, 0.92 or less, 0.90 or less, or 0.88 or less.

[0088] The above c represents the molar ratio of cobalt in the lithium composite transition metal oxide, and may be 0 or more and 0.2 or less, and as a specific example, may be 0.001 or more, 0.005 or more, 0.01 or more, 0.02 or more, or 0.04 or more, and may also be 0.18 or less, 0.16 or less, 0.14 or less, 0.12 or less, 0.1 or less, or 0.05 or less.

[0089] The above d represents the molar ratio of manganese in the lithium composite transition metal oxide, and may be greater than 0 and less than or equal to 0.4, and as specific examples, may be 0.01 or more, 0.03 or more, 0.05 or more, 0.7 or more, or 0.09 or more, and may also be 0.35 or less, 0.3 or less, 0.25 or less, 0.2 or less, 0.15 or less, or 0.1 or less.

[0090] The above e represents the molar ratio of aluminum in the lithium composite transition metal oxide, and may be 0 or more and 0.1 or less, and as specific examples, may be 0.005 or more, 0.01 or more, 0.015 or more, 0.02 or more, or 0.025 or more, and may also be 0.097 or less, 0.094 or less, 0.09 or less, 0.087 or less, 0.084 or less, or 0.08 or less.

[0091] The above f is M in lithium complex transition metal oxide 2It represents the molar ratio, and may be 0 or more and 0.1 or less, and as a specific example, it may be 0.005 or more, 0.01 or more, 0.015 or more, 0.02 or more, or 0.025 or more, and also, it may be 0.097 or less, 0.094 or less, 0.09 or less, 0.087 or less, 0.084 or less, or 0.08 or less.

[0092]

[0093] According to one embodiment of the present invention, the cathode material has an average particle diameter (D) of 1 ㎛ or more and 15 ㎛ or less. 50 ) and specifically, may be 1.5 ㎛ or more, 2 ㎛ or more, 3 ㎛ or more, 4 ㎛ or more, or 5 ㎛ or more, and may also be 13 ㎛ or less, 11 ㎛ or less, 9 ㎛ or less, 8 ㎛ or less, or 7 ㎛ or less.

[0094]

[0095] According to one embodiment of the present invention, the positive electrode active material included in the positive electrode material may further include a coating layer disposed on the surface of the lithium composite transition metal oxide. The coating layer may include at least one selected from the group consisting of Li, Ni, Co, Mn, B, F, Mg, Al, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, and Gd.

[0096]

[0097] <Cathode material manufacturing method>

[0098] The present invention provides a method for manufacturing a cathode material.

[0099] The method for manufacturing a cathode material of the present invention comprises the steps of mixing a lithium raw material and a transition metal raw material (S1);

[0100] The method comprises a step (S2) of firing the mixture mixed in the step S1 at a temperature of 700°C or higher and 1200°C or lower, wherein the step S2 comprises: a step (S2-1-1) of first firing at a first temperature, a step (S2-1-2) of cooling the first fired product fired in the step (S2-1-1), and a step (S2-1-3) of second firing the first fired product cooled in the step (S2-1-2) at a second temperature different from the first temperature, or a step (S2-2-1) of first firing at a third temperature, and a step (S2-2-2) of second firing at a fourth temperature different from the third temperature continuously following the first firing in the step (S2-2-1).

[0101]

[0102] A method for manufacturing a cathode material according to one embodiment of the present invention is a solid-phase synthesis method in which solid-phase raw materials of each element constituting the cathode active material are mixed and fired, thereby vaporizing and flying away inorganic substances contained in the raw materials and forming oxides. Accordingly, compared to a conventional method for manufacturing a single-particle type cathode active material based on a precursor synthesized by a co-precipitation method, additional manufacturing costs and environmental problems associated with precursor processing and washing / drying are prevented, and a high Mn concentration region is formed in the single-particle type cathode active material, thereby providing an effect similar to coating a portion of the surface of the cathode active material or doping an internal region, thereby improving life characteristics and stability.

[0103]

[0104] A method for manufacturing a cathode material according to one embodiment of the present invention includes a step (S1) of mixing a lithium raw material and a transition metal raw material.

[0105]

[0106] According to one embodiment of the present invention, the lithium raw material may be at least one selected from the group consisting of lithium hydroxide (LiOH), lithium hydroxide hydrate (LiOH·H2O), and lithium carbonate (Li2CO3).

[0107]

[0108] According to one embodiment of the present invention, the transition metal raw material may refer to a solid-phase raw material of each of Ni, Co, and Mn of the chemical formula 1, or a combination of two of them (e.g., a combination of Ni and Co, a combination of Ni and Mn, a combination of Co and Mn). The transition metal raw material according to one embodiment of the present invention is different from a conventional precursor synthesized by a coprecipitation method in which Ni, Co, and Mn are all included in a single compound. Specifically, the transition metal raw material may be at least one or more of the metal, hydroxide, oxide, carbonate, sulfate, sulfide, phosphate, nitrate, chloride, and acetate forms of each of Ni, Co, and Mn, or a combination of two of them.

[0109] According to one embodiment of the present invention, the transition metal raw material has an average particle diameter (D) of 0.1 ㎛ or more and 15 ㎛ or less by volume. 50 ) and specifically, it may be 0.2 ㎛ or more, 0.5 ㎛ or more, 1.0 ㎛ or more, 1.5 ㎛ or more, or 2.0 ㎛ or more, and further, it may be 13 ㎛ or less, 10 ㎛ or less, 8 ㎛ or less, 6 ㎛ or less, or 4 ㎛ or less.

[0110]

[0111] According to one embodiment of the present invention, the step (S1) may further include adding and mixing a doping element raw material in addition to the lithium raw material and the transition metal raw material.

[0112] In this case, the doping element raw material is M of the chemical formula 1 1Refers to the raw material of the above M 1 It may be in at least one of the following forms: metal, hydroxide, oxide, carbonate, sulfate, sulfide, phosphate, nitrate, chloride, acetate.

[0113]

[0114] A method for manufacturing a cathode material according to one embodiment of the present invention includes a step (S2) of firing the mixture mixed in step (S1) at a temperature of 700°C or more and 1200°C or less.

[0115]

[0116] According to one embodiment of the present invention, the step (S2) may be performed by a first method (S2-1) including a step (S2-1-1) of first firing at a first temperature, a step (S2-1-2) of cooling the first fired product fired in the step (S2-1-1), and a step (S2-1-3) of second firing the first fired product cooled in the step (S2-1-2) at a second temperature.

[0117]

[0118] According to one embodiment of the present invention, the step (S2-1-1) of the first method (S2-1) may be a step of preparing a first mixture by mixing each of the transition metal raw materials including the nickel raw material in the S1 step in such an amount that the molar ratio of nickel (Ni) to the transition metal of the positive electrode active material is 50 mol% or more with the first lithium raw material such that the molar ratio of lithium (Li) to non-lithium (Li) elements included in the positive electrode active material to be prepared is 0.80 to 1.2 times, and first firing the first mixture at a first temperature under an oxygen partial pressure of 10 to 100%.

[0119]

[0120] According to one embodiment of the present invention, the step (S2-1-2) of the first method (S2-1) may be a step of cooling the primary fired material fired in the step (S2-1-1), and a crushing process of crushing the cooled fired material may be additionally performed.

[0121]

[0122] According to one embodiment of the present invention, the step (S2-1-3) of the first method (S2-1) may be a step of additionally mixing a second lithium raw material into the first fired product cooled in the step (S2-1-2) so that the total molar ratio of lithium (Li) to non-lithium (Li) elements included in the positive electrode active material to be manufactured is 0.8 to 1.2 times and firing the mixture at a second temperature, or a step of secondary firing the first fired product cooled in the step (S2-1-2) at an oxygen partial pressure of 10 to 100% at a second temperature without adding a separate lithium raw material.

[0123]

[0124] According to one embodiment of the present invention, the first lithium raw material and the second lithium raw material may each be at least one selected from the group consisting of lithium hydroxide (LiOH), lithium hydroxide hydrate (LiOH H2O), and lithium carbonate (Li2CO3). In addition, the first lithium raw material and the second lithium raw material may be the same or different from each other.

[0125]

[0126] According to one embodiment of the present invention, in the step (S2-1-3), the doping element raw material, i.e., M of the chemical formula 1 1 At least one or more of the metal, hydroxide, oxide, carbonate, sulfate, sulfide, phosphate, nitrate, chloride, and acetate forms may be additionally added.

[0127] In addition, according to one embodiment of the present invention, the doping element raw material may be separately introduced in the step (S1) and the step (S2-1-3).

[0128]

[0129] According to one embodiment of the present invention, the first temperature and the second temperature may each have different temperatures. In this case, the first temperature and the second temperature may each have a range of 700°C or more and 1200°C or less and may be different temperatures.

[0130] According to one embodiment of the present invention, the second temperature may be lower than the first temperature. In this case, the first temperature may be 865°C or higher and 1200°C or lower, and the second temperature may be 700°C or higher and 860°C or lower. As a more specific example, the first temperature may be 870°C or higher, 880°C or higher, 890°C or higher, 900°C or higher, or 910°C or higher, and further may be 1150°C or lower, 1100°C or lower, 1050°C or lower, 1000°C or lower, or 950°C or lower. Meanwhile, the second temperature may be 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, or 750°C or higher, and further may be 850°C or lower, 840°C or lower, 830°C or lower, 820°C or lower, or 810°C or lower.

[0131] When the first temperature and the second temperature each satisfy the temperature range described above, a high Mn concentration region can be formed in the positive electrode active material in the form of a single particle.

[0132]

[0133] According to one embodiment of the present invention, the first firing may be performed for 2 hours or more and 30 hours or less. Specifically, the first firing may be performed for 5 hours or more, 8 hours or more, 11 hours or more, 13 hours or more, or 15 hours or more, and may also be performed for 28 hours or less, 26 hours or less, 24 hours or less, 22 hours or less, or 20 hours or less.

[0134] According to one embodiment of the present invention, the secondary firing may be performed for 2 hours or more and 30 hours or less. Specifically, the primary firing may be performed for 5 hours or more, 8 hours or more, 11 hours or more, 13 hours or more, or 15 hours or more, and may also be performed for 28 hours or less, 26 hours or less, 24 hours or less, 22 hours or less, or 20 hours or less.

[0135]

[0136] According to one embodiment of the present invention, the step (S2) may be performed by a second method (S2-2) including a step (S2-2-1) of performing a first firing at a third temperature, and a step (S2-2-2) of performing a second firing at a fourth temperature different from the third temperature, consecutively following the first firing of the step (S2-2-1). Meanwhile, performing a second firing consecutively following the first firing means that the second firing is performed immediately following the first firing without a separate process between the first firing and the second firing. In other words, it means performing a single firing process, but applying a temperature change during the firing process.

[0137]

[0138] According to one embodiment of the present invention, the step (S2-2-1) of the second method (S2-2) may be a step of preparing a mixture by mixing each of the transition metal raw materials including the nickel raw material in the step S1 so that the molar ratio of nickel (Ni) to the transition metal of the positive electrode active material is 50 mol% or more with the lithium raw material so that the molar ratio of lithium (Li) to non-lithium (Li) included in the positive electrode active material to be prepared is 0.80 to 1.2 times, and firing the mixture at a third temperature under an oxygen partial pressure of 10 to 100%.

[0139]

[0140] According to one embodiment of the present invention, the step (S2-2-2) of the second method (S2-2) may be a step of performing a second firing at a fourth temperature different from the third temperature immediately following the first firing of the step (S2-2-1) without a separate cooling process.

[0141] According to one embodiment of the present invention, the lithium raw material may be at least one selected from the group consisting of lithium hydroxide (LiOH), lithium hydroxide hydrate (LiOH·H2O), and lithium carbonate (Li2CO3), as described above.

[0142] According to one embodiment of the present invention, the third temperature and the fourth temperature may each have different temperatures. In this case, the third temperature and the fourth temperature may each have a range of 700°C or more and 1200°C or less and may be different temperatures.

[0143] According to one embodiment of the present invention, the fourth temperature may be higher than the third temperature. In this case, the fourth temperature may be 865°C or higher and 1200°C or lower, and the third temperature may be 700°C or higher and 860°C or lower. As a more specific example, the fourth temperature may be 870°C or higher, 880°C or higher, 890°C or higher, 900°C or higher, or 910°C or higher, and further, 1150°C or lower, 1100°C or lower, 1050°C or lower, 1000°C or lower, or 950°C or lower. Meanwhile, the third temperature may be 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, or 750°C or higher, and may also be 850°C or lower, 840°C or lower, 830°C or lower, 820°C or lower, or 810°C or lower.

[0144] According to one embodiment of the present invention, the fourth temperature may be lower than the third temperature. In this case, the third temperature may be 865°C or higher and 1200°C or lower, and the fourth temperature may be 700°C or higher and 860°C or lower. As a more specific example, the third temperature may be 870°C or higher, 880°C or higher, 890°C or higher, 900°C or higher, or 910°C or higher, and further may be 1150°C or lower, 1100°C or lower, 1050°C or lower, 1000°C or lower, or 950°C or lower. Meanwhile, the fourth temperature may be 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, or 750°C or higher, and further may be 850°C or lower, 840°C or lower, 830°C or lower, 820°C or lower, or 810°C or lower.

[0145] When the third temperature and the fourth temperature each satisfy the temperature range described above, a high Mn concentration region can be formed in the positive electrode active material in the form of a single particle.

[0146]

[0147] According to one embodiment of the present invention, the second method (S2-2) may be performed at the third temperature for 2 hours or more and 30 hours or less. Specifically, the first firing may be performed for 5 hours or more, 8 hours or more, 11 hours or more, 13 hours or more, or 15 hours or more, and may also be performed for 28 hours or less, 26 hours or less, 24 hours or less, 22 hours or less, or 20 hours or less.

[0148] According to one embodiment of the present invention, the second method (S2-2) may be performed at the fourth temperature for 2 hours or more and 30 hours or less. Specifically, the first firing may be performed for 5 hours or more, 8 hours or more, 11 hours or more, 13 hours or more, or 15 hours or more, and may also be performed for 28 hours or less, 26 hours or less, 24 hours or less, 22 hours or less, or 20 hours or less.

[0149] A method for manufacturing a positive electrode active material according to one embodiment of the present invention may further include a step (S3) of mixing a coating element raw material into the resultant product generated after the step (S2) and firing the resultant product at a temperature of 200°C or higher and 900°C or lower at an oxygen partial pressure of 10 to 100%.

[0150] According to one embodiment of the present invention, when the step (S2) is performed by the first method (S2-1), the step (S3) can be performed by further mixing a coating element raw material into the secondary firing result of the first method (S2-1) and firing at a temperature of 200°C or higher and 900°C or lower at an oxygen partial pressure of 10 to 100%.

[0151] According to one embodiment of the present invention, when the step (S2) is performed by the second method (S2-2), the step (S3) can be performed by further mixing a coating element raw material into the continuous firing result of the second method (S2-2) and firing at a temperature of 200°C or higher and 900°C or lower at an oxygen partial pressure of 10 to 100%.

[0152]

[0153] According to one embodiment of the present invention, the step (S3) may be performed for 1 hour or more and 20 hours or less. Specifically, the step (S3) may be performed for 2 hours or more, 3 hours or more, 4 hours or more, 5 hours or more, or 6 hours or more, and may also be performed for 18 hours or less, 16 hours or less, 14 hours or less, 12 hours or less, or 10 hours or less.

[0154]

[0155] According to one embodiment of the present invention, the coating element raw material may be at least one of a metal, hydroxide, oxide, carbonate, sulfate, sulfide, phosphate, nitrate, chloride, and acetate form selected from the group consisting of Li, Ni, Co, Mn, B, F, Mg, Al, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, and Gd.

[0156]

[0157] Bipolar

[0158] According to one embodiment of the present invention, a cathode including the above cathode material is provided.

[0159] Specifically, the positive electrode includes a positive electrode current collector, and a positive electrode active material layer formed on the positive electrode current collector and including the positive electrode active material described above.

[0160] According to one embodiment of the present invention, the positive electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 to 500 ㎛, and fine unevenness may be formed on the surface of the current collector to increase the adhesive strength of the positive electrode active material. For example, the positive electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0161] According to one embodiment of the present invention, the positive electrode active material layer may include a conductive material and a binder together with the positive electrode active material described above.

[0162] According to one embodiment of the present invention, at this time, the conductive material is used to provide conductivity to the electrode, and in the battery to be constructed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any particular limitation. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, and carbon fiber; metal powder or metal fiber such as copper, nickel, aluminum, and silver; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like, and one type alone or a mixture of two or more types thereof may be used. The conductive material may typically be included in an amount of 0.3 to 30 wt% based on the total weight of the positive electrode active material layer.

[0163] According to one embodiment of the present invention, the binder serves to improve adhesion between positive electrode active material particles and adhesion between the positive electrode active material and the current collector. Specific examples thereof include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. The binder may be included in an amount of 0.3 to 30 wt% based on the total weight of the positive electrode active material layer.

[0164] According to one embodiment of the present invention, the positive electrode can be manufactured according to a conventional positive electrode manufacturing method, except that the positive electrode active material described above is used. Specifically, the positive electrode active material layer forming composition, which is manufactured by mixing or dispersing the positive electrode active material and optionally a binder and a conductive agent in a solvent, is applied onto a positive electrode current collector, followed by drying and rolling. At this time, the types and contents of the positive electrode active material, binder, and conductive agent are as described above.

[0165] According to one embodiment of the present invention, the solvent may be a solvent generally used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one of these may be used alone or as a mixture of two or more. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, and binder 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.

[0166] 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.

[0167]

[0168] Lithium secondary battery

[0169] According to one embodiment of the present invention, an electrochemical device including the positive electrode is provided. The electrochemical device may be, specifically, a battery, a capacitor, or the like, and more specifically, a lithium secondary battery.

[0170] According to one embodiment of the present invention, the lithium secondary battery specifically includes a positive electrode, a negative electrode positioned opposite the positive electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte, wherein the positive electrode is as described above. In addition, the lithium secondary battery may optionally further include a battery container that houses an electrode assembly of the positive electrode, the negative electrode, and the separator, and a sealing member that seals the battery container.

[0171] According to one embodiment of the present invention, in the 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.

[0172] According to one embodiment of the present invention, the negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the negative electrode current collector can typically have a thickness of 3 to 500 ㎛, and like the positive electrode current collector, fine unevenness can be formed on the surface of the current collector to strengthen the bonding strength of the negative electrode active material. For example, it can be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc.

[0173] According to one embodiment of the present invention, the negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material.

[0174] According to one embodiment of the present invention, a compound capable of reversible intercalation and deintercalation of lithium may be used as the negative electrode active material. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiO x(0 < x < 2), SnO2, vanadium oxide, lithium vanadium oxide, and other metal oxides capable of doping and dedoping lithium; or composites containing the above metallic compounds and carbonaceous materials, such as Si-C composites or Sn-C composites, and 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 fiber-like forms, 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.

[0175] Additionally, the binder and the conductive material may be the same as those described above for the positive electrode.

[0176] According to one embodiment of the present invention, the negative electrode active material layer may be manufactured by, for example, applying a negative electrode forming composition prepared by dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent, onto a negative electrode current collector and drying the coating, or by casting the negative electrode forming composition onto a separate support and then laminating the film obtained by peeling it off from the support onto a negative electrode current collector.

[0177] 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 as a separator in lithium secondary batteries can be used without special 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, can 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. can also be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength can be used, and can optionally be used in a single-layer or multi-layer structure.

[0178] In addition, examples of the electrolyte used in the present invention include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries.

[0179] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0180] According to one embodiment of the present invention, the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (wherein R is a C2 to C20 linear, branched, or cyclic hydrocarbon group, and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable.In this case, the performance of the electrolyte may be improved when the cyclic carbonate and the chain carbonate are mixed and used in a volume ratio of about 1:1 to about 1:9.

[0181] According to one embodiment of the present invention, the lithium salt may be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, or LiB(C2O4)2. It is preferable that the concentration of the lithium salt be used 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.

[0182] According to one embodiment of the present invention, in addition to the electrolyte components, the electrolyte may further include one or more additives, such as, for example, a haloalkylene carbonate compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, a cyclic ether, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 5 wt% based on the total weight of the electrolyte.

[0183] According to one embodiment of the present invention, a lithium secondary battery including a cathode active material according to the present invention stably exhibits excellent discharge capacity, output characteristics, and capacity retention rate, 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).

[0184]

[0185] 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.

[0186]

[0187] Example 1

[0188] Ni(OH)2(D 50 5 μm), Co(OH)2(D 50 0.3 ㎛), MnO2(D 50 1 μm), Al(OH)3(D 50The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1 (1 ㎛), and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.02:1, and the weight ratio of Zr to the positive electrode active material was 1500 ppm and Y to 1000 ppm, based on the theoretical yield, and then calcined at 890 ℃ for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0189]

[0190] Example 2

[0191] Ni(OH)2 (D50 is 5㎛), Co(OH)2 (D50 is 0.3㎛), MnO2 (D50 is 0.5㎛), Al(OH)3 (D50 is 1㎛) raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and LiOH·H2O (the first lithium raw material) was mixed so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.02:1, and the weight ratio of Zr to the positive electrode active material based on the theoretical yield was 1500 ppm, Y was 1000 ppm, and then fired at 890℃ for 6 hours (first firing) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0192]

[0193] Example 3

[0194] Ni(OH)2(D 50 4㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.5㎛), Al(OH)3(D 50The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.02:1, and the weight ratio of Zr to the positive electrode active material was 1500 ppm and Y to 1000 ppm, based on the theoretical yield, and then calcined at 890°C for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0195]

[0196] Example 4

[0197] Ni(OH)2(D 50 3㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.5㎛), Al(OH)3(D 50The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.02:1, and the weight ratio of Zr to the positive electrode active material was 1500 ppm and Y to 1000 ppm, based on the theoretical yield, and then calcined at 890°C for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0198]

[0199] Example 5

[0200] Ni(OH)2(D 50 3㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.3㎛), Al(OH)3(D 50The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1 (1㎛), and the molar ratio of LiOH (the first lithium raw material) was 1.03:1 (Ni+Co+Mn+Al), and the weight ratio of Zr was 1500 ppm and Y was 1000 ppm compared to the positive electrode active material based on the theoretical yield, and then calcined at 870°C for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0201]

[0202] Example 6

[0203] Ni(OH)2(D 50 3㎛), Co3O4(D 50 0.5㎛), MnO2(D 50 0.3㎛), Al(OH)3(D 50The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.03:1, and the weight ratio of Zr to the positive electrode active material was 1500 ppm and Y to 1000 ppm, based on the theoretical yield, and then calcined at 870°C for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0204]

[0205] Example 7

[0206] Ni(OH)2(D 50 3㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.3㎛), Al(OH)3(D 50The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.03:1, and the weight ratio of Zr to the positive electrode active material was 1500 ppm and Y to 1000 ppm, based on the theoretical yield, and then calcined at 885°C for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed into the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0207]

[0208] Example 8

[0209] Ni(OH)2(D 50 3㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.3㎛), Al(OH)3(D 50The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1, and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.03:1, and the weight ratio of Zr to 1500 ppm and Y to 1000 ppm compared to the positive electrode active material based on the theoretical yield was calcined at 885 ℃ for 6 hours, and then immediately calcined continuously at 820 ℃ for 10 hours, and then Co(OH)2 and Al(OH)3 were mixed in the resultant of the continuous calcination so that the weight ratio of Co to 13000 ppm and Al to 500 ppm compared to the positive electrode active material based on the theoretical yield was heat-treated at 700 ℃ for 3 hours to manufacture a positive electrode active material.

[0210]

[0211] Example 9

[0212] Ni(OH)2(D 50 3㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50 0.3㎛), Al(OH)3(D 50 The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1 (1㎛), and the molar ratio of LiOH·H2O (the first lithium raw material) was 1.03:1, and the weight ratio of Zr was 1500 ppm and Y was 1000 ppm compared to the positive electrode active material based on the theoretical yield, and the raw materials were fired at 885°C for 6 hours, and then immediately fired continuously at 820°C for 10 hours to manufacture the positive electrode active material.

[0213]

[0214] Example 10

[0215] Ni(OH)2(D 50 4㎛), Co(OH)2(D 50 0.3㎛), Mn3O4(D 50The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn was 60:10:30, the molar ratio of Li2CO3 (the first lithium raw material) was 1.03:1, and the weight ratio of Zr was 2000 ppm, and Y was 1500 ppm compared to the positive electrode active material based on the theoretical yield, and then calcined at 950°C for 8 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn) was 1.05:1, and calcined at 820°C for 8 hours (second calcination), and Al2O3 and WO3 were mixed into the second calcination result so that the weight ratio of Al was 1500 ppm and W was 3000 ppm compared to the positive electrode active material based on the theoretical yield, and heat-treated at 500°C for 6 hours to manufacture a positive electrode active material.

[0216]

[0217] Example 11

[0218] Ni(OH)2(D 50 4㎛), Co(OH)2(D 50 0.3㎛), MnO2(D 50The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn was 60:10:30, the molar ratio of Li2CO3 (the first lithium raw material) was 1.03:1, and the weight ratio of Zr was 2000 ppm, and Y was 1500 ppm compared to the positive electrode active material based on the theoretical yield, and then calcined at 950°C for 8 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn) was 1.05:1, and calcined at 820°C for 8 hours (second calcination), and Al2O3 and WO3 were mixed into the second calcination result so that the weight ratio of Al was 1500 ppm and W was 3000 ppm compared to the positive electrode active material based on the theoretical yield, and heat-treated at 500°C for 6 hours to manufacture a positive electrode active material.

[0219]

[0220] Example 12

[0221] Ni(OH)2(D 50 4㎛), Co(OH)2(D 50 0.3㎛), Mn3O4(D 50The raw materials were mixed in a solid phase so that the molar ratio of Ni:Co:Mn was 60:10:30, the molar ratio of Li2CO3 (the first lithium raw material) was 1.03:1, and the weight ratio of Zr was 2000 ppm, and Y was 1500 ppm compared to the positive electrode active material based on the theoretical yield, and then calcined at 950°C for 8 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O (second lithium raw material) was additionally mixed into the first calcination result so that the molar ratio of Li:(Ni+Co+Mn) was 1.05:1, and calcined at 760°C for 8 hours (second calcination), and Al2O3 and WO3 were mixed into the second calcination result so that the weight ratio of Al was 1500 ppm and W was 3000 ppm compared to the positive electrode active material based on the theoretical yield, and heat-treated at 500°C for 6 hours to manufacture a positive electrode active material.

[0222]

[0223] Example 13

[0224] Ni(OH)2(D 50 4㎛), Co(OH)2(D 50 0.3㎛), Mn3O4(D 50 The raw materials (1㎛) were mixed in a solid phase so that the molar ratio of Ni:Co:Mn was 60:10:30, and the molar ratio of Li2CO3 (the first lithium raw material) was 1.03:1, and the weight ratio of Zr to 2000 ppm and Y to 1500 ppm compared to the positive electrode active material based on the theoretical yield was calcined at 850 ℃ for 5 hours, and then immediately calcined continuously at 950 ℃ for 10 hours, and then Al2O3 and WO3 were mixed in the resultant of the continuous calcination so that the weight ratio of Al to 1500 ppm and W to 3000 ppm compared to the positive electrode active material based on the theoretical yield was heat-treated at 500 ℃ for 6 hours to manufacture a positive electrode active material.

[0225]

[0226] Comparative Example 1

[0227] After preparing NCM(OH)2 precursor having a composition of Ni:Co:Mn molar ratio of 89:3:8 by co-precipitation method, it was mixed with Al(OH)3(D 50 The raw materials were mixed with 1㎛) to make the molar ratio of Ni:Co:Mn:Al 88:3:8:1, LiOH·H2O to make the molar ratio of Li:(Ni+Co+Mn+Al) 1.03:1, and Zr 1500 ppm, Y 1000 ppm by weight ratio compared to the cathode material based on the theoretical yield, and then calcined at 870℃ for 6 hours (first calcination) and cooled to room temperature. Afterwards, LiOH·H2O was added to the first calcination result so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, mixed, and calcined at 820°C for 10 hours (second calcination), and Co(OH)2 and Al(OH)3 were mixed to the second calcination result so that Co was 13,000 ppm and Al was 500 ppm in weight ratio compared to the positive electrode active material based on the theoretical yield, and heat-treated at 700°C for 3 hours to manufacture a positive electrode active material.

[0228]

[0229] Comparative Example 2

[0230] After preparing NCM(OH)2 precursor having a composition of Ni:Co:Mn molar ratio of 89:3:8 by co-precipitation method, it was mixed with Al(OH)3(D 50Mix with 1㎛) so that the molar ratio of Ni:Co:Mn:Al becomes 88:3:8:1, and LiOH·H2O so that the molar ratio of Li:(Ni+Co+Mn+Al) becomes 1.03:1, and the raw materials are mixed so that the weight ratio of Zr is 1500 ppm and Y is 1000 ppm compared to the cathode material based on the theoretical yield, and then fired at 885 ℃ for 6 hours (first firing), and then LiOH·H2O is added to the result of the first firing so that the molar ratio of Li:(Ni+Co+Mn+Al) becomes 1.04:1, and then mixed, and fired at 820 ℃ for 10 hours (second firing), and then Co(OH)2 and Al(OH)3 are added to the result of the second firing so that the weight ratio of Co is 13000 ppm and Al is 500 ppm compared to the cathode active material based on the theoretical yield. The positive electrode active material was manufactured by mixing and heat treating at 700°C for 3 hours.

[0231]

[0232] Comparative Example 3

[0233] After preparing NCM(OH)2 precursor having a composition of Ni:Co:Mn molar ratio of 89:3:8 by co-precipitation method, it was mixed with Al(OH)3(D 50 The raw materials were mixed so that the molar ratio of Ni:Co:Mn:Al was 88:3:8:1 and LiOH·H2O was mixed so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.03:1, and the weight ratio of Zr was 1500 ppm and Y was 1000 ppm compared to the cathode material based on the theoretical yield, and then fired at 885 ℃ for 6 hours (first firing), and LiOH·H2O was added to the result of the first firing so that the molar ratio of Li:(Ni+Co+Mn+Al) was 1.04:1, mixed, and fired at 820 ℃ for 10 hours to manufacture a cathode material.

[0234]

[0235] Comparative Example 4

[0236] After preparing an NCM(OH)2 precursor having a composition of Ni:Co:Mn molar ratio of 60:10:30 by a co-precipitation method, Li2CO3 is mixed so that the molar ratio of Li:(Ni+Co+Mn) is 1.03:1, and the raw materials are mixed so that the weight ratio of Zr is 2000 ppm and Y is 1500 ppm compared to the cathode material based on the theoretical yield, and then calcined at 950 ℃ for 8 hours (first calcination), and LiOH·H2O is added to the resultant of the first calcination so that the molar ratio of Li:(Ni+Co+Mn) is 1.05:1, and mixed, and calcined at 820 ℃ for 8 hours (second calcination), and Al2O3 and WO3 are mixed so that the weight ratio of Al is 1500 ppm and W is 3000 ppm compared to the cathode active material based on the theoretical yield, and 500 The positive electrode active material was manufactured by heat treatment at ℃ for 6 hours.

[0237]

[0238] Experimental example

[0239] Experimental Example 1: EPMA Image Analysis

[0240] <EPMA Mn 농도 스케일 바 세팅>

[0241] For each of the positive electrode active materials of the above examples and comparative examples, Mn mol% was obtained using an inductively coupled plasma optical emission spectrometer (ICP-OES; PerkinElmer, Optima 8000DV). The EPMA Mn concentration scale bar was set with the maximum value of the obtained Mn mol% of the positive electrode active materials of the above examples and comparative examples, and the minimum value was obtained by dividing the obtained Mn mol% of the positive electrode active materials of the above examples and comparative examples by 3 and rounding down to the nearest tenth.

[0242] Specifically, in the case of Examples 1 to 9 and Comparative Examples 1 to 3 in which the Mn mol% was 8 mol% in the ICP analysis results, the maximum value (max) of the EPMA Mn concentration scale bar is set to 8 concentration%, and the minimum value (min) is set to 2 concentration% (8 / 3 = 2.666..). In addition, in the case of Examples 10 to 13 and Comparative Example 4 in which the Mn mol% was 30 mol% in the ICP analysis results, the maximum value (max) of the EPMA Mn concentration scale bar is set to 30 concentration%, and the minimum value (min) is set to 10 concentration%.

[0243]

[0244] <EPMA 분석>

[0245] The positive electrode active material, carbon black conductive agent, and PVDF binder of each of the above examples and comparative examples were mixed in a weight ratio of 95:2:3 in an N-methylpyrrolidone (NMP) solvent to prepare a positive electrode slurry. The prepared positive electrode slurry was applied to one surface of an aluminum current collector, dried at 130°C, and then rolled to a porosity of 20% to prepare a positive electrode.

[0246] To obtain a flat cross-section for EPMA cross-section analysis, the anode was subjected to Ar-ion milling using a HITACHI IM-5000 instrument at an acceleration voltage of 6 kV to obtain a cross-section of the anode sample. Then, the cross-sectional image of the anode sample was observed using a JEOL JXA-iHP200F instrument at an acceleration voltage of 15 kV and a probe current of 50 nA. The Mn content in the EPMA image was extracted using the Analysis-Intensity function of the PC-EPMA software provided by JEOL. At this time, the ROI (region of interest) for composition extraction was set to a rectangle as large as possible within the particle from which the content was to be extracted.

[0247]

[0248] Experimental Example 2: Battery Characteristics Evaluation (Examples 1 to 9, Comparative Examples 1 to 3)

[0249] The positive electrode active material, carbon black conductive material, and PVDF binder of each of Examples 1 to 9 and Comparative Examples 1 to 3 were mixed in a weight ratio of 95:2:3 in an N-methylpyrrolidone solvent to prepare a positive electrode composite, which was then applied to one surface of an aluminum current collector, dried at 130°C, and rolled to prepare a positive electrode having a porosity of 20%.

[0250] An electrode assembly was manufactured by using a lithium metal electrode as a negative electrode and interposing a porous polyethylene separator between the positive electrode and the negative electrode manufactured as described above. The electrode assembly was positioned inside a case, and a coin-type half-cell was manufactured by injecting an electrolyte solution in which lithium hexafluorophosphate (LiPF6) having a concentration of 1.0 M was dissolved in an organic solvent consisting of ethylene carbonate / ethyl methyl carbonate / diethyl carbonate / (mixed volume ratio of EC / EMC / DEC = 3 / 4 / 3).

[0251] Using each lithium secondary battery coin-type half cell manufactured as described above, the battery was charged at 0.1 C in CCCV mode at 25 ℃ until 4.25 V and maintained at 4.25 V up to A of 0.01 C. Afterwards, the battery was discharged to 2.5 V with a constant current of 0.1 C to conduct a charge / discharge experiment. The charge capacity and discharge capacity were measured and shown in Table 1 below. In addition, the battery was charged at 45 ℃ at 0.5 C until 4.25 V and discharged to 2.5 V with a constant current of 1.0 C to conduct a charge / discharge experiment 50 times. The life maintenance rate and resistance increase rate were measured and shown in Table 1 below.

[0252]

[0253] Experimental Example 3: Battery Characteristics Evaluation (Examples 10 to 13, Comparative Example 4)

[0254] The positive electrode active materials, carbon black conductive agents, and PVDF binders of each of Examples 10 to 13 and Comparative Example 4 were mixed in a weight ratio of 95:2:3 in an N-methylpyrrolidone solvent to prepare a positive electrode composite, which was then applied to one surface of an aluminum current collector, dried at 130°C, and rolled to prepare a positive electrode having a porosity of 20%.

[0255] An electrode assembly was manufactured by using a lithium metal electrode as a negative electrode and interposing a porous polyethylene separator between the positive electrode and the negative electrode manufactured as described above. The electrode assembly was positioned inside a case, and a coin-type half-cell was manufactured by injecting an electrolyte solution in which lithium hexafluorophosphate (LiPF6) having a concentration of 1.0 M was dissolved in an organic solvent consisting of ethylene carbonate / ethyl methyl carbonate / diethyl carbonate / (mixed volume ratio of EC / EMC / DEC = 3 / 4 / 3).

[0256] Using each of the lithium secondary battery coin-type half cells manufactured as described above, Examples 10 to 13 and Comparative Example 4 were charged at 25°C in CCCV mode at 0.1 C until 4.4 V, and 4.4 V was maintained until A at 0.01 C. Afterwards, the charge capacity and discharge capacity were measured when a charge / discharge experiment was conducted by discharging to 2.5 V at a constant current of 0.1 C, and the results are shown in Table 2 below.

[0257]

[0258] The positive electrode active materials, carbon black conductive agents, and PVDF binders of Examples 10 to 13 and Comparative Example 4 were mixed in a weight ratio of 95:2:3 in an N-methylpyrrolidone solvent to prepare a positive electrode composite, which was then coated on one side of an aluminum current collector, dried at 130°C, and rolled to prepare a positive electrode with a porosity of 20%. The negative electrode was prepared by mixing natural graphite and artificial graphite in a 5:5 ratio to prepare a negative electrode counter electrode. The electrolyte was prepared with a salt concentration of 0.7 M, and LiFSI (Lithium bis(fluorosulfonyl)imide, 0.3 M) was added to maintain the lifespan. The amount of the solution was calculated to be 100 uL per electrode, and a separator manufactured by the company was positioned between the positive and negative electrodes with an appropriate size. The electrolyte was added to the prepared monocell, formation charge and discharge were performed, and the initial gas was removed to conduct a monocell evaluation.

[0259] High temperature life characteristics were measured by charging to 4.35 V at 0.33 C with a constant current at 45°C, discharging to 2.5 V with a constant current of 0.33 C, and 100 th The capacity retention rate and resistance increase rate of cyc. were measured and shown in Table 2 below.

[0260]

[0261] Number of observed high Mn concentration regions 25 ℃ 0.1 / 0.1 C CHC 45 ℃ 0.5 / 1.0 C CHC Charge (mAh / g) Discharge (mAh / g) Efficiency (%) Resistance (Ω) 50th cyc Lifespan (%) 50th cyc Resistance increase (%) Example 131 231.7 206.3 89.0 18.2 96.8 146.9 Example 217 232.1 206.6 89.0 18.3 96.7 143.3 Example 310 232.1 206.1 88.8 18.0 96.8 141.8 Example 45 231.7 207.0 89.3 17.8 96.7 142.9 Example 52232.0207.889.617.797.2140.5Example 65231.8208.389.917.197.4138.5Example 71231.4206.389.218.497.3137.9Example 825231.5207.189.516.896.9143.9Example 911230.5201.287.322.394.0160.8Comparative Example 1-231.4206.889.417.396.0157.5Comparative Example 2-231.4206.889.416.495.8158.0Comparative Example 3-230.3201.089.323.093.2175.8* Maximum Mn concentration observed in Comparative Example 1: 4.16% concentration* Maximum Mn concentration observed in Comparative Example 2: 4.44% concentration* Maximum Mn concentration observed in Comparative Example 3: 4.29% concentration

[0262] Number of observed high Mn concentration regions 25 ℃ 0.1 / 0.1 C CHC 45 ℃ 0.33 / 0.33 C MC Charge (mAh / g) Discharge (mAh / g) Efficiency (%) Resistance (Ω) 100th cyc Lifespan Maintenance (%) 100th cyc Resistance Increase (%) Example 107 215.9 195.09 0.3 21.8 9 5.6 3 2.3 Example 119 216.2 194.9 0.2 2.2 9 5.5 27.4 Example 121 3216.0 196.6 1.0 22.0 9 5.7 3 0.4 Example 131 6216.0 196.5 9 1.0 22.6 9 5.9 29.5 Comparative Example 4-216.0196.090.722.495.540.9* Maximum Mn concentration observed in Comparative Example 4: 17.1% concentration

[0263] Referring to Tables 1 and 2 and FIGS. 1 to 17, it can be confirmed that a high Mn concentration region is observed in the cross-section of the positive electrode active material of Examples 1 to 13, and that a high Mn concentration region is not observed in the cross-section of the positive electrode active material of Comparative Examples 1 to 4.

[0264] Specifically, in the case of Examples 1 to 9 in which the Mn mol% was 8 mol% as a result of the ICP analysis, a high Mn concentration region exceeding 5% concentration, which is the point where the maximum value (max; 8% concentration) and minimum value (min; 2% concentration) of the set EPMA Mn concentration scale bar are divided 1:1, is observed. However, in the case of Comparative Examples 1 to 3, it was confirmed that the high Mn concentration region was not observed because the observed maximum Mn concentration did not exceed 5% concentration.

[0265] In addition, in the case of Examples 10 to 13 in which the Mn mol% was 30 mol% as a result of the ICP analysis, a high Mn concentration region exceeding 20% ​​concentration, which is the point where the maximum value (max; 30% concentration) and minimum value (min; 10% concentration) of the set EPMA Mn concentration scale bar are divided 1:1, was observed. However, in the case of Comparative Example 4, it was confirmed that the high Mn concentration region was not observed because the observed maximum Mn concentration did not exceed 20% concentration.

[0266]

[0267] In the case of Examples 1 to 8, in which surface treatment is performed, the Mn mol% of the positive electrode active material measured by ICP is 8 mol%, and a high Mn concentration region is observed, it can be confirmed that the positive electrode active material has an excellent lifespan maintenance rate and a small resistance increase rate compared to Comparative Examples 1 and 2, in which surface treatment is performed, the Mn mol% of the positive electrode active material measured by ICP is 8 mol%, and a high Mn concentration region is not observed.

[0268] In addition, in the case of Example 9, in which no surface treatment was performed, the Mn mol% of the positive electrode active material measured by ICP was 8 mol%, and a high Mn concentration region was observed, it was confirmed that the positive electrode active material had an excellent lifespan maintenance rate and a small resistance increase rate compared to Comparative Example 3, in which no surface treatment was performed, the Mn mol% of the positive electrode active material measured by ICP was 8 mol%, and a high Mn concentration region was not observed.

[0269] In addition, in the case of Examples 10 to 13, in which surface treatment was performed, the Mn mol% of the positive electrode active material measured by ICP was 30 mol%, and a high Mn concentration region was observed, it was confirmed that the positive electrode active material had an excellent lifespan maintenance rate and a small resistance increase rate compared to Comparative Example 4, in which surface treatment was performed, the Mn mol% of the positive electrode active material measured by ICP was 30 mol%, and a high Mn concentration region was not observed.

Claims

1. A cathode material comprising a cathode active material in the form of a single particle, When the cross-section of the positive electrode including the positive electrode material is measured by EPMA under the conditions of an acceleration voltage of 15 kV and a probe current of 50 nA, a high Mn concentration region existing on the cross-section of the positive electrode active material is observed in the EPMA image. The above high Mn concentration region is, The maximum value (max) of the Mn concentration scale bar of the above EPMA image is taken as the Mn mol% value of the positive electrode active material analyzed by ICP (Inductive Coupled Plasma), When the minimum value (min) of the Mn concentration scale bar of the above EPMA image is the value obtained by dividing the Mn mol% of the positive electrode active material analyzed by ICP by 3 and rounding down to the first decimal place, A cathode material having a Mn concentration % greater than or equal to a point where the maximum value (max) and minimum value (min) of the Mn concentration scale bar of the EPMA image are divided 1:

1.

2. In paragraph 1, A cathode material in which the high Mn concentration region has an area ratio of 1 / 100 or more compared to the cross-sectional area of ​​one cathode active material particle in which the high Mn concentration region is observed.

3. In paragraph 1, A cathode material wherein the high Mn concentration region is distributed on the surface and / or inside of the cathode active material.

4. In paragraph 1, A cathode material in which the above high Mn concentration region is distributed within the interior of the cathode active material.

5. In paragraph 1, The average particle diameter (D) of the above positive electrode active material 50 ) is a cathode material having a diameter of 1 ㎛ or more and 15 ㎛ or less.

6. In paragraph 1, The above positive electrode active material is a positive electrode material including a lithium composite transition metal oxide represented by the following chemical formula 1: [Chemical Formula 1] Li w Ni x Co y Mr z M 1 1-x-y-z O2 In the above chemical formula 1, M 1 is at least one selected from the group consisting of B, F, Mg, Al, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd, 0.8≤w≤1.2, 0.5≤x<1.0, 0≤y≤0.2, 0 <z≤0.4이다.

7. In paragraph 1, The above positive electrode active material is a positive electrode material including a lithium composite transition metal oxide represented by the following chemical formula 2: [Chemical Formula 2] Li a Ni b Co c Mr d Al e M 2 f O2 In the above chemical formula 2, M 2 is at least one selected from the group consisting of B, F, Mg, Si, P, Ca, Sc, Ti, V, Cr, Fe, Ga, Sr, Y, Zr, Nb, Mo, Ba, La, Hf, Ta, W, Bi, Ce, Sm, Gd, 0.8≤a≤1.2, 0.5≤b<1.0, 0≤c≤0.2, 0 <d≤0.4, 0≤e≤0.1, 0≤f≤0.1, b+c+d+e+f = 1이다.

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