Anode active materials and methods for preparing anode active materials

Abstract

The invention relates to an anode active material consisting of single-particle transition metal lithium oxides containing 80% mole or more of the nickel content of all metals except lithium, and composed of 1 to 30 small particles, in which the cation mixing ratio satisfies a specific equation, and a method for preparing an anode active material, which includes, firstly, mixing transition metal precursor oxides containing 80% mole or more of the nickel content of all metals with anhydrous lithium material to prepare a mixture, and secondly, calcining the mixture to prepare single-particle transition metal lithium oxides composed of 1 to 30 small particles, in which the ratio between D50 of the anhydrous lithium material and D50 of the transition metal precursor oxide is between 4 and 20.

Description

Cathode active material and method for producing the same This application claims the benefit of priority to Korean Patent Application No. 10-2023-0154027, filed November 8, 2023, and Korean Patent Application No. 10-2024-0154763, filed November 4, 2024, the entire contents of which are incorporated herein by reference. The present invention relates to a positive electrode active material having a controlled orientation of primary particles, a method for producing the same, a positive electrode including the positive electrode active material, and a lithium secondary battery. 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. Lithium secondary batteries produce electrical energy through oxidation and reduction reactions when lithium ions are inserted / deintercalated between the positive and negative electrodes, which are made of active materials capable of intercalating and deintercalating lithium ions, while charging an organic electrolyte or polymer electrolyte between them. Lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2 or LiMn2O4, etc.), and lithium iron phosphate compound (LiFePO4) have been mainly used as cathode active materials for lithium secondary batteries. Meanwhile, as a method to improve the low thermal stability of LiNiO2 while maintaining the excellent reversible capacity, lithium composite metal oxides (hereinafter simply referred to as 'NCM oxides') in which some of the nickel is replaced with cobalt and manganese have been developed. However, the conventionally developed NCM oxides had insufficient capacity characteristics, limiting their application. To overcome these limitations, recent research has been conducted to increase the nickel content in NCM oxides. However, high-nickel cathode materials with high nickel content generate large amounts of gas during charge / discharge due to the high reactivity of nickel. Furthermore, they suffer from significant lattice structural instability due to cation mixing and oxygen desorption, and an increase in the content of lithium impurities remaining on the surface. Therefore, there is a need to develop a cathode material that has excellent capacity and structural stability while including a high nickel content. The present invention aims to provide a single-particle high-nickel positive electrode active material in which crystal deformation and cation mixing ratio are controlled within certain conditions, and a method for manufacturing the same. [1] The present invention provides a cathode active material comprising a single particle lithium transition metal oxide having a nickel content of 80 mol% or more among metals other than lithium and consisting of 1 to 30 nodules, and a cation mixing ratio (P) satisfying the following equation 1. [Formula 1] In the above equation 1, P is the cation mixing ratio value of the positive electrode active material, X is the content value of nickel among metals other than lithium in the above lithium transition metal oxide, The above cation mixing ratio is measured in at%, the nickel content is measured in mol%, but P and X are unitless numbers excluding units. S is 10 for the crystal strain 6 It is the product of . [2] The present invention, in the above [1], D of the positive electrode active material 50 A positive electrode active material having a diameter of 3.0㎛ to 6.0㎛ is provided. [3] The present invention provides a positive electrode active material in the above [1] or [2], wherein the lithium transition metal oxide has a composition represented by the following chemical formula 1. [Chemical Formula 1] Li 1+x (Ni a Co b M 1 c M 2 d )O2 In the above chemical formula 1, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0≤x≤0.50, 0.80≤a≤1, 0≤b≤0.20, 0≤c≤0.20, 0≤d≤0.10, a+b+c+d=1. [4] The present invention provides a positive electrode active material, wherein the positive electrode active material has a cation mixing ratio of 2.0 at% or less in at least one of the above [1] to [3]. [5] The present invention provides a positive electrode active material, wherein, in at least one of the above [1] to [4], when the positive electrode active material is pressed with a force of 12 tons, the rate of generation of fine particles having a particle size of 1 ㎛ or less is 2.0 vol% or less based on the total volume of the positive electrode active material. [6] The present invention provides a positive electrode active material, wherein in at least one of the above [1] to [5], the positive electrode active material has a single particle magnetization degree of 3.0 or more and 4.5 or less according to the following formula 2. [Formula 2] In the above equation 2, R iis the radius value of the i-th grain measured when the electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode is analyzed by backscatter electron diffraction (EBSD). The radius of the above grain is measured in μm, but Ri is a unitless number excluding the unit. n is the total number of grains measured through the above EBSD analysis, which is 350 to 450. [7] The present invention provides a positive electrode active material, wherein in at least one of the above [1] to [6], the positive electrode active material includes LiOH and Li2CO3 on the particle surface, and the total weight of the LiOH and Li2CO3 is 0.50 wt% or less relative to the total weight of the positive electrode active material. [8] The present invention comprises a first step of preparing a mixture by mixing a transition metal precursor oxide having a nickel content of 80 mol% or more among the total metal and an anhydrous lithium raw material; a second step of preparing a single particle lithium transition metal oxide composed of 1 to 30 nodules by calcining the mixture, wherein D of the transition metal precursor oxide 50 D of the above anhydrous lithium raw material 50 A method for manufacturing a positive electrode active material having a ratio of 4 to 20 is provided. [9] The present invention provides a method for producing a positive electrode active material, wherein the transition metal precursor oxide has a composition represented by the following chemical formula 2 in the above [8]. [Chemical Formula 2] Ni a1 Co b1 M 1 c1 M 2 d1 O In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, M 2is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0.80≤a1≤1, 0≤b1≤0.20, 0≤c1≤0.20, 0≤d1≤0.10, a1+b1+c1+d1=1.

[0010] The present invention, in the above [8] or [9], D of the transition metal precursor oxide 50 A method for manufacturing a positive electrode active material having a diameter of 3 μm to 6 μm is provided.

[0011] The present invention, in at least one of the above [8] to

[0010] , D of the anhydrous lithium raw material 50 A method for manufacturing a positive electrode active material having a diameter of 12 μm to 60 μm is provided.

[0012] The present invention provides a method for producing a positive electrode active material, wherein, in at least one of the above [8] to

[0011] , the sintering in the second step is performed at 650°C to 900°C.

[0013] The present invention provides a method for producing a positive electrode active material, wherein, in at least one of the above [8] to

[0012] , the raw material loss rate according to the following formula 3 is 5 wt% or less. [Formula 3] [1-{Weight of manufactured lithium transition metal oxide / (Input weight of transition metal precursor oxide + Input weight of anhydrous lithium raw material)}] × 100(%)

[0014] The present invention provides a positive electrode comprising at least one positive electrode active material among the above [1] to [7].

[0015] The present invention provides a lithium secondary battery comprising a positive electrode according to the above

[0014] ; a negative electrode including a negative electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte. The positive electrode active material according to the present invention exhibits low crystal deformation, i.e., a stable structure, and thus has the advantage of less structural deformation and consequent electrode degradation during the rolling process or battery operation. In addition, the above-mentioned positive electrode active material has the advantage of low irreversible capacity and excellent charge / discharge efficiency because it has a low cation mixing ratio. In addition, since the above-mentioned positive electrode active material includes a single-particle lithium transition metal oxide, it has excellent particle strength and thus has less particle breakage during rolling, thereby preventing problems such as side reactions with the electrolyte due to particle breakage and gas generation resulting therefrom. In addition, since the lithium transition metal oxide contains a high content of nickel, there is an advantage in that high capacity can be achieved. In addition, in the present invention, by using an oxide precursor instead of a conventional hydroxide precursor as a precursor during the synthesis of a positive electrode active material, the reaction yield can be increased, raw material loss can be reduced, and the sintering temperature can be lowered. In addition, in the present invention, since an anhydrous lithium raw material is used instead of a conventional hydrous lithium raw material when synthesizing a positive electrode active material, the amount of lithium raw material used can be reduced, the sintering temperature can be lowered, and the quality of the positive electrode active material can be prevented from being deteriorated by moisture. In addition, in the present invention, D of the precursor oxide is used in the synthesis of the positive electrode active material. 50 D of the above anhydrous lithium raw material 50 Since the ratio is controlled within a certain range, it has the effect of improving the uniformity of the reaction between the precursor and the lithium raw material. Figure 1 is a photograph of the positive electrode active material particles manufactured in Example 1 observed through a scanning electron microscope (SEM). Figure 2 is a photograph of the positive electrode active material particles manufactured in Example 2 observed through a scanning electron microscope (SEM). Figure 3 is a photograph of the positive electrode active material particles manufactured in Comparative Example 1 observed through a scanning electron microscope (SEM). Figure 4 is a photograph of the positive electrode active material particles manufactured in Comparative Example 2 observed through a scanning electron microscope (SEM). Figure 5 is a photograph of the positive electrode active material particles manufactured in Comparative Example 3 observed through a scanning electron microscope (SEM). Figure 6 is a photograph of the positive electrode active material particles manufactured in Comparative Example 4 observed through a scanning electron microscope (SEM). Figure 7 is a photograph of the positive electrode active material particles manufactured in Comparative Example 5 observed through a scanning electron microscope (SEM). Hereinafter, the present invention will be described in more detail to help understand the present invention. In the present invention, “single particle type” means a particle composed of 30 or fewer nodules, and is a concept that includes a single particle composed of one nodule and a pseudo-single particle which is a composite of 2 to 30 nodules. The above "nodule" is a sub-particle unit that constitutes a single particle and a pseudo-single particle, and may be a single crystal without a crystalline grain boundary, or a polycrystal with no apparent grain boundary when observed under a magnification of 5,000 to 20,000 times using a scanning electron microscope. In the present invention, “particle” is a concept including one or all of a single particle, a pseudo-single particle, a primary particle, and a nodule. In the present invention, "D 50" refers to the particle size corresponding to 50% of the volume accumulation in the volume accumulation particle size distribution of the corresponding particle powder, and can be measured using a laser diffraction method. For example, after dispersing the positive electrode active material powder in a dispersion medium, it can be measured by introducing it into a commercially available laser diffraction particle size measuring device (e.g., Malvern, Mastersizer 3000) and irradiating it with ultrasonic waves of about 28 kHz at an output of 60 W, obtaining a volume accumulation particle size distribution graph, and finding the particle size at the point where the volume accumulation amount is 50% in the obtained volume accumulation particle size distribution graph. In the present invention, the "cation mixing ratio" is defined as the nickel ion (Ni) based on the total amount of lithium sites (Li sites) in the lithium layer of the lithium nickel oxide having a layered structure. 2+ ) refers to the ratio (at%) of the mixture, and can be measured through X-ray diffraction analysis (XRD). In the present invention, “at%” means atomic percentage. In the present invention, “crystal strain” is a dimensionless number representing the degree of lattice distortion caused by a defect, i.e., the degree of crystal lattice deformation, and can be measured through Rietveld refinement analysis of XRD data. The above X-ray diffraction analysis can be performed using a Bruker D8 Endeavor (light source: Cu-Kα, λ=1.54Å) equipped with a LynxEye XE-T-position sensitive detector. The sample is placed in the groove of a general powder holder, the sample surface is leveled using a slide glass, and the sample is filled so that the height matches the edge of the holder. Then, it can be performed under the conditions of FDS 0.5°, 2θ=15° to 90°, step size=0.02°, and total scan time=approximately 20 minutes. Rietveld refinement is performed on the measured data by considering the charge at each site (metals at transition metal sites are +3, Ni at Li sites is +2) and cation mixing. Instrumental broadening during analysis is performed using the Fundamental Parameter Approach (FPA) implemented in the Bruker TOPAS program, and the entire peaks of the measurement range are used for fitting. Peak shape is fitted using only the Lorenzian contribution as the FP (First Principle) among the peak types available in TOPAS. 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 the grain can be measured by image analysis of the EBSD map. positive electrode active material As mentioned above, increasing the nickel content in the cathode active material can secure higher capacity, but it also reduces structural stability. Specifically, high-nickel cathode active materials retain a large amount of lithium compounds on their surfaces, which can cause side reactions during charge / discharge, generating gases and degrading stability. Furthermore, high-nickel cathode active materials suffer from significant changes in lattice constants, i.e., changes in volume within the unit cell. These volume changes can cause cracks within the active material particles. These cracks can lead to voids within the active material, potentially degrading battery performance. In addition, as the nickel content is high, the phenomenon of cation mixing of lithium ions and nickel ions occurs frequently, which hinders the movement of lithium ions when the battery is operated, causing an increase in battery resistance and a deterioration in lifespan. Accordingly, the inventors of the present invention intend to provide a cathode active material having excellent structural stability due to low crystal deformation and cation mixing ratio while containing a high nickel content, and a method for manufacturing the same. The cathode active material according to the present invention comprises a single particle lithium transition metal oxide having a nickel content of 80 mol% or more among metals other than lithium and composed of 1 to 30 nodules, and a cation mixing ratio (P) satisfies the following equation 1. [Formula 1] In the above equation 1, P is the cation mixing ratio value of the positive electrode active material, X is the content value of nickel among metals other than lithium in the above lithium transition metal oxide, The above cation mixing ratio is measured in at%, the nickel content is measured in mol%, but P and X are unitless numbers excluding units. S is 10 for the crystal strain 6 It is the product of . Specifically, the cation mixing ratio corresponding to the above P may be 2.0 at% or less, preferably 1.5 at% or less, and more preferably 1.3 at% or less. The cation mixing may be Li having similar ionic radii. + Wow Ni 2+ Since it means the phenomenon of forming a crystal by exchanging positions with each other, if the cation mixing ratio is high, Li + Li when inserted and removed + Ni present in the spatial layer 2+ It is preferable that it be less than 2.0 at%, as it can act as a resistance component and reduce the charge / discharge efficiency. The content of nickel among the metals other than lithium in the lithium transition metal oxide corresponding to the above X may be 80 mol% or more, preferably 83 mol% or more, and more preferably 90 mol% or more. In this case, there is an advantage in that high capacity can be implemented. As the nickel content in the positive electrode active material increases, Ni 3+ As Ni increases 2+ The mixing ratio of cations affected by the decreases, and the above equation 1 can represent the electrochemical characteristics of the positive electrode active material in a composition in which the content of nickel among metals other than lithium is 80 mol% or more. The crystal strain corresponding to the above S is 300×10 -6 Below, preferably 290×10 -6 Below, more preferably 280×10 -6 This may be the case. A high crystal strain indicates low structural stability, so if it does not meet the above range, the structure may easily collapse during the electrode rolling process or battery operation, which is undesirable. Conversely, a cathode active material with a crystal strain that satisfies the above range has a high structural completeness, which can contribute to increasing the energy density of the cathode and reducing gas generation during high-temperature storage and operation of the battery. Meanwhile, the lithium transition metal oxide may include nickel, cobalt, and manganese. In addition, the lithium transition metal oxide may have a composition represented by the following chemical formula 1. [Chemical Formula 1] Li 1+x (Ni a Co b M 1 c M 2 d )O2 In the above chemical formula 1, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0≤x≤0.50, 0.80≤a≤1, 0≤b≤0.20, 0≤c≤0.20, 0≤d≤0.1, a+b+c+d=1. The above 1+x represents the molar ratio of lithium in the lithium transition metal oxide, and may be 0≤x≤0.20, or 0≤x≤0.10. When the molar ratio of lithium satisfies the above range, the crystal structure can be formed stably. The above a represents the molar ratio of nickel among the total metals excluding lithium in the lithium transition metal oxide, and may be 0.83≤a<1, 0.85≤a<1, or 0.90≤a<1. When the molar ratio of nickel satisfies the above range, a high energy density is exhibited, enabling high capacity implementation. The above b represents the molar ratio of cobalt among all metals excluding lithium in the lithium transition metal oxide, and is 0. <b≤0.15, 0<b≤0.12, 또는 0<b≤0.07일 수 있다. 코발트의 몰비가 상기 범위를 만족할 때, 양호한 저항 특성 및 출력 특성을 구현할 수 있다. The above c is M of all metals excluding lithium in the lithium transition metal oxide. 1 It represents the molar ratio of elements, 0 <c≤0.15, 0<c≤0.10, 또는 0<c≤0.07일 수 있다. 한편 상기 M 1 may be Mn; or a combination of Mn and Al, preferably Mn. The above d is M of all metals excluding lithium in the lithium transition metal oxide. 2 Indicates the molar ratio of elements, and d may be 0≤d≤0.08, 0≤d≤0.05, or 0≤d≤0.03. Meanwhile, since the lithium transition metal oxide according to the present invention is in the form of a single particle composed of 1 to 30 nodules, the particle strength is higher than that of the conventional secondary particle type cathode active material in which tens to hundreds of primary particles are aggregated, so that particle breakage hardly occurs during rolling. In addition, in the case of the single particle type cathode active material, since the number of primary particles constituting the particle is small, the change due to volume expansion and contraction of the primary particles during charge and discharge is small, and accordingly, the occurrence of cracks inside the particle is also significantly reduced. That is, when using a cathode active material including a single particle type lithium transition metal oxide according to the present invention, the phenomenon of reduced life characteristics due to particle breakage and internal cracking that occurred when using a cathode active material including a conventional secondary particle type lithium transition metal oxide can be significantly improved. In addition, D of the above positive electrode active material 50 The D of the positive electrode active material may be 3.0 ㎛ to 6.0 ㎛, preferably 3.5 ㎛ to 5.0 ㎛, and more preferably 4.0 ㎛ to 4.5 ㎛. 50Although it is desirable that the size is 3.0㎛ or more to prevent agglomeration between nodules, improve electrode processability, and reduce the amount of lithium byproducts, if the size of the cathode active material becomes excessively large, particle breakage may become severe, so it is desirable that the size is 6.0㎛ or less to reduce particle breakage and improve life characteristics and high-temperature storage characteristics. In addition, D 50 Increasing the sintering temperature or increasing the sintering time to grow D increases the crystal deformation and cation mixing ratio, so it is also necessary to implement a positive electrode active material satisfying the above equation 1. 50 It is desirable to control within this range. In addition, when the positive electrode active material is pressed with a force of 12 tons, the rate of generation of fine particles having a particle size of 1 μm or less may be 2.0 vol% or less, preferably 1.5 vol% or less, and more preferably 1.0 vol% or less, based on the total volume of the positive electrode active material. In this case, since the particles have excellent durability against rolling, not only can the energy density be increased by increasing the rolling intensity as needed, but also the amount of gas generated due to side reactions during operation or storage at high temperatures can be reduced and the lifespan can be improved. In addition, the above-mentioned positive electrode active material may have a single particle magnetization degree of 3.0 or more and 4.5 or less according to the following equation 2, and specifically, may be 3.1 or more, or 3.2 or more. [Formula 2] In the above equation 2, R i is the radius value of the i-th grain measured when the electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode is analyzed by backscatter electron diffraction (EBSD). The radius of the above grain is measured in μm, but Ri is a unitless number excluding the unit. n is the total number of grains measured through the above EBSD analysis, which is 350 to 450. A higher degree of single particle size indicates a greater number of single particle-shaped positive electrode active material particles within the positive electrode active material, which improves high-temperature performance. However, if the degree of single particle size exceeds 4.5, the resistance may become excessively high, degrading output and capacity characteristics. Therefore, the degree of single particle size may be 4.5 or less, 4.0 or less, or 3.5 or less. Also, R of the above formula 1 i The grain diameter corresponding to may be 0.4 µm to 2.5 µm, specifically 0.5 µm to 2.0 µm, and more specifically 0.6 µm to 1.0 µm. Meanwhile, the average grain diameter of the positive electrode active material measured through EBSD may be 1.0 µm to 4.5 µm, preferably 1.2 µm to 3.0 µm, and more preferably 1.4 µm to 2.0 µm. When the average grain diameter of the positive electrode active material satisfies the above range, particle breakage is reduced, which is advantageous in improving the capacity retention rate of the battery. Meanwhile, the positive electrode active material includes LiOH and Li2CO3 as residual lithium byproducts on the particle surface, and the total weight of the LiOH and Li2CO3 may be 0.50 wt% or less, preferably 0.45 wt% or less, based on the total weight of the positive electrode active material. In this case, since it means that the amount of lithium byproducts acting as resistance is small, the charge / discharge efficiency can be increased and the amount of gas generated by side reactions can be reduced. Specifically, the total weight of LiOH may be 0.20 wt% or less, or 0.17 wt% or less, and the total weight of Li2CO3 may be 0.30 wt% or less, or 0.28 wt% or less, based on the total weight of the positive electrode active material. The content of LiOH and Li2CO3 can be confirmed through pH titration of the positive electrode active material. Meanwhile, the positive electrode active material may be a mixture of the single-particle lithium transition metal oxide and the secondary particle lithium transition metal oxide having a larger particle size than the single-particle lithium transition metal oxide. Method for manufacturing positive electrode active material Hereinafter, a method for manufacturing a positive electrode active material according to the present invention will be described. The method for manufacturing the positive electrode active material of the present invention is as follows: A first step of preparing a mixture by mixing a transition metal precursor oxide having a nickel content of 80 mol% or more among the total metal and anhydrous lithium raw material; A second step of producing a single particle lithium transition metal oxide composed of 1 to 30 nodules by calcining the above mixture, D of the above transition metal precursor oxide 50 (D P ) for the above anhydrous lithium raw material D 50 (D L ) of the ratio (D) L / D P ) is 4 or more and 20 or less. Like this D L / D P By adjusting the D of the precursor oxide to 4~20, the uniformity of the positive electrode active material synthesis reaction is improved and the yield is increased. 50 (D P ) is the target positive electrode active material D 50 Considering that the degree of adjustment is limited because it is set to fit D L / D P D of lithium raw material 50 (D L ) acts as a major factor. At this time D L / D P If this is less than 4, i.e. D L In this small case, a lithium raw material with a larger surface area is used based on the same weight, and there is a problem that the yield is lower because the larger the surface area, the easier it is to vaporize. On the other hand, DL / D P If this exceeds 20, i.e. D L In this case, it is difficult to mix homogeneously due to the size difference with the precursor oxide, so a structurally incomplete cathode active material or a cathode active material with a large amount of residual lithium may be synthesized. That is, D L / D P If this is 4 or more and 20 or less, it is desirable to increase the structural completeness of the positive electrode active material while securing an appropriate amount of yield and to reduce the amount of residual lithium. Ultimately, D L / D P This can contribute to the production of a cathode active material satisfying the above formula 1 in that the lithium diffusion in the precursor oxide during sintering is improved due to the appropriate surface area and homogeneity of 4 or more and 20 or less, leading to the production of a cathode active material with excellent structural stability (i.e., low crystal deformation and cation mixing ratio). Specifically, the above D L / D P It may preferably be 5 or more, 8 or more, or 10 or more, and 18 or less, 16 or less, or 14 or less. Next, we will explain each step in detail. 1) Stage 1 First, a transition metal precursor oxide having a nickel content of 80 mol% or more and anhydrous lithium raw material are mixed in a reactor. Specifically, the content of nickel among the metals in the transition metal precursor oxide may be 83 mol% or more, preferably 85 mol% or more, and more preferably 90 mol% or more. In this case, there is an advantage of being able to implement high capacity. The above transition metal precursor oxide may include nickel, cobalt, and manganese. In addition, the above transition metal precursor oxide may have a composition represented by the following chemical formula 2. [Chemical Formula 2] Ni a1 Cob1 M 1 c1 M 2 d1 O In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0.80≤a1≤1, 0≤b1≤0.20, 0≤c1≤0.20, 0≤d1≤0.10, a1+b1+c1+d1=1. The above a1 represents the molar ratio of nickel among all metals excluding lithium in the transition metal precursor oxide, and may be 0.83≤a1<1, 0.85≤a1<1, or 0.90≤a1<1. The above b1 represents the molar ratio of cobalt among all metals excluding lithium in the transition metal precursor oxide, and is 0. <b1≤0.15, 0<b1≤0.10, 또는 0<b1≤0.05일 수 있다. The above c1 is M among all metals except lithium in the above transition metal precursor oxide. 1 It represents the molar ratio of elements, 0 <c≤0.15, 0<c≤0.10, 또는 0<c≤0.05일 수 있다. 한편 상기 M 1 may be Mn; or a combination of Mn and Al. The above d1 is M among all metals except lithium in the above transition metal precursor oxide. 2 Indicating the molar ratio of elements, d1 may be 0≤d1≤0.08, 0≤d1≤0.05, or 0≤d1≤0.03. The above transition metal precursor oxide can be prepared by oxidizing a precursor in the form of a hydroxide commonly used in the art, for example, by heat treating the precursor in the form of a hydroxide in an oxygen atmosphere or reacting it with an oxidizing agent. As the above anhydrous lithium raw material, anhydrides such as lithium-containing sulfate, nitrate, acetate, carbonate, oxalate, citrate, halide, hydroxide or oxyhydroxide can be used, and for example, Li2CO3, LiNO3, LiNO2, LiOH, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7 or mixtures thereof can be used. Specifically, the above anhydrous lithium raw material can be anhydrous LiOH, and the anhydrous LiOH can be manufactured by a method of crushing LiOH H2O, vacuum drying, and then crushing again. When a transition metal precursor oxide and anhydrous lithium raw material are used as in the present invention (reaction formula 1 below), the production yield can be increased compared to when a hydroxide precursor and a lithium raw material in the form of a hydrate (reaction formula 2 below). In reaction formulas 1 and 2 below, the numbers in parentheses represent molecular weights, and M represents a metal element other than Ni, and the molecular weight of M is not reflected. Comparing reaction formulas 1 and 2, it can be confirmed that the yield, which represents the weight of the produced lithium transition metal oxide (LiNiMO2) relative to the weight of the input raw material, is much higher in reaction formula 1. [Reaction Formula 1] LiOH (24.0) + NiMO (74.7) → LiNiMO2 (97.6) + 1 / 2H2 (1) (yield: 97.6 / 98.7=98.89%) [Reaction Formula 2] LiOH·H2O(42.0) + NiM(OH)2(92.7) → LiNiMO2(97.6) +2H2O(36) + 1 / 2H2(1) (Yield: 97.6 / 134.7=72.46%) In addition, in the method for manufacturing a positive electrode active material according to one embodiment of the present invention, the raw material loss rate according to the following formula 3 may be 5 wt% or less, preferably 3 wt% or less, and more preferably 1 wt% or less. The raw material loss rate is equal to the value obtained by subtracting the yield described above from 100%. [Formula 3] [1-{Weight of manufactured lithium transition metal oxide / (Input weight of transition metal precursor oxide + Input weight of anhydrous lithium raw material)}] × 100(%) In addition, when using a lithium raw material in the form of a hydroxide precursor and a hydrate, the process of LiOH·H2O → LiOH and the process of NiM(OH)2 → NiMO are required during the sintering process, whereas when using a transition metal precursor oxide and anhydrous lithium raw material as in the present invention, there is no need to go through these processes, and thus the sintering temperature can be lowered. In other words, even when sintering at a lower temperature than the conventional single-particle sintering temperature, the same level of particle characteristics can be obtained. In addition, the use of an oxide precursor and anhydrous lithium raw material can contribute to the production of a positive electrode active material satisfying the above formula 1 by increasing the BET specific surface area of ​​the positive electrode active material during oxidation, thereby enhancing reactivity. Meanwhile, the anhydrous lithium raw material and the transition metal precursor oxide may be mixed so that the molar ratio of Li: total metal in the precursor is 1:1 to 1.2:1, preferably 1:1 to 1.1:1. When the mixing ratio of the lithium raw material and the metal in the precursor satisfies the above range, the layered crystal structure of the lithium composite transition metal oxide is well developed, so that a positive electrode active material with excellent capacity characteristics and structural stability can be manufactured. In addition, D of the above-mentioned positive electrode active material 50 To achieve this, the D of the above transition metal precursor oxide 50 The silver may be 3.0㎛ to 6.0㎛, preferably 3.0㎛ to 5.0㎛. In addition, D of the above anhydrous lithium raw material 50 The D of the anhydrous lithium raw material may be 12 ㎛ to 60 ㎛, preferably 15 ㎛ to 55 ㎛, and more preferably 20 ㎛ to 50 ㎛. 50 D when in this range L / D P It is easy to implement the above-described effect by adjusting it to 4~20. 2) Stage 2 After the first step, a step of calcining the mixture prepared in the first step to prepare a single-particle lithium transition metal oxide is performed. The above calcination can be performed under an oxygen atmosphere at 650°C to 900°C, preferably 650°C to 850°C, and more preferably 700°C to 800°C for 10 to 15 hours. In order to produce a single-particle lithium transition metal oxide, it is common to calcinate at a temperature of at least 800°C or higher, but in the present invention, since the transition metal precursor in the form of an oxide and the anhydrous lithium raw material are used as described above, a single-particle form can be obtained even when calcined at such a relatively low temperature. Considering that the higher the sintering temperature, the better the particle growth reaction occurs, which can increase the degree of single particle formation, it is preferable that it is 650℃ or higher. However, considering that the Li2O content increases due to high-temperature sintering, which is easily converted to LiOH, and LiOH is easily converted again to Li2CO3, which can cause side reactions with the electrolyte and gas generation, it is preferable that it is 900℃ or lower. Here, the oxygen atmosphere means an atmosphere containing oxygen sufficient for sintering, including the air atmosphere. In particular, it is preferable to perform the sintering in an atmosphere with a higher oxygen partial pressure than the air atmosphere. Meanwhile, the second step may further include a milling step after the firing. The above milling process is intended to remove large particles and achieve a particle size within the desired range for the positive electrode active material powder. The milling process may be performed using a common milling method known in the art, such as a jet mill, but is not limited thereto. anode Next, the anode according to the present invention will be described. The positive electrode according to the present invention comprises the positive electrode active material according to the present invention. Specifically, the positive electrode comprises: a positive electrode current collector; and a positive electrode active material layer formed on the positive electrode current collector and comprising the positive electrode active material. In the above positive electrode, 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 positive electrode current collector to increase the adhesive strength of the positive electrode active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric. Additionally, the positive electrode active material layer may include a conductive material and a binder together with the positive electrode active material described above. The above positive electrode active material may typically be included in an amount of 80 wt% to 99 wt%, preferably 90 wt% to 98 wt%, and more preferably 95 wt% to 97 wt%, based on the total weight of the positive electrode active material layer. 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 particular limitation. Specific examples include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; carbon-based materials such as carbon fibers and carbon nanotubes; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and 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 typically be included in an amount of 0.5 wt% to 20 wt%, preferably 1 wt% to 10 wt%, and more preferably 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer. The above binder serves to improve adhesion between positive electrode active material particles and adhesion between the positive electrode active material and the positive electrode 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, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, 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 0.5 wt% to 20 wt%, preferably 1 wt% to 10 wt%, and more preferably 1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer. The above positive electrode can be manufactured according to a conventional positive electrode manufacturing method. For example, the positive electrode can be manufactured by mixing a positive electrode active material, a binder, and / or a conductive agent in a solvent to manufacture a positive electrode slurry, applying the positive electrode slurry onto a positive electrode current collector, and then drying and rolling. The solvent may be a solvent generally used in the relevant technical field, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), 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, and binder, taking into account 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. Alternatively, the positive electrode may be manufactured by casting the positive electrode slurry onto a separate support, then peeling the resulting film from the support and laminating it onto a positive electrode current collector. lithium secondary battery Next, a lithium secondary battery according to the present invention will be described. The lithium secondary battery specifically includes a positive electrode, a negative electrode including a negative electrode active material, 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 will be omitted, and only the remaining components will be described in detail below. 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. 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. 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. The above negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material. 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 one embodiment of the present invention, the negative electrode active material may be graphite, the Si-containing material, or a mixture thereof, and specifically, may be graphite, and more specifically, a mixture of artificial graphite and natural graphite. In addition, a metallic lithium thin film may be used as the negative electrode active material. The negative electrode active material may be included in an amount of 80 wt% to 99 wt% based on the total weight of the negative electrode active material layer. 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. 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. The above negative electrode active material layer can be manufactured by applying and drying a negative electrode composite 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 negative electrode composite on a separate support and then laminating the obtained film by peeling it off from the support on a negative electrode current collector. 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 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. 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. Specifically, the electrolyte may include an organic solvent and a lithium salt. 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. 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, LiAlO2, 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 4.0 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. 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, triethyl phosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphate 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. There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be a cylindrical shape using a can, a square shape, a pouch shape, or a coin shape. As described above, since the lithium secondary battery including the positive electrode active material according to the present invention exhibits stable high-temperature performance, it can be used not only as a battery cell used as a power source for small devices such as mobile phones, laptop computers, and digital cameras, but can also be preferably used as a unit battery of a battery module for medium- to large-sized devices including a plurality of battery cells. Examples of the above medium and large devices include, but are not limited to, power tools, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems. According to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided. Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. [Example: Preparation of positive electrode active material] Example 1. D50 =4㎛ and Ni 0.83 Co 0.10 Mn 0.07 having the composition of O Precursor oxide and D 50 =20㎛ and anhydrous LiOH was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and the center speed was 400 rpm and mixed for 20 minutes. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni] as a cathode active material. 0.83 Co 0.10 Mn 0.07 ]A lithium transition metal oxide having a composition of O2 was prepared. Example 2. D 50 =4.5㎛ and Ni 0.90 Co 0.05 Mn 0.05 having the composition of O Precursor oxide and D 50 =50㎛ and anhydrous LiOH was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and the center speed was 400 rpm and mixed for 20 minutes. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni] as a cathode active material. 0.90 Co 0.05 Mn 0.05 ]A lithium transition metal oxide having a composition of O2 was prepared. Comparative Example 1. D 50 =4㎛ and Ni 0.83 Co 0.10 Mn 0.07 Having a composition of (OH)2 Precursor hydroxide and D 50=20㎛ LiOH·H2O was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and mixed for 20 minutes at a center speed of 400 rpm. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni] as a cathode active material. 0.83 Co 0.10 Mn 0.07 ]A lithium transition metal oxide having a composition of O2 was prepared. Comparative Example 2. D 50 =4㎛ and Ni 0.83 Co 0.10 Mn 0.07 Having a composition of (OH)2 Precursor hydroxide and D 50 =20㎛ LiOH·H2O was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and mixed for 20 minutes at a center speed of 400 rpm. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 820°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni] as a cathode active material. 0.83 Co 0.10 Mn 0.07 ]A lithium transition metal oxide having a composition of O2 was prepared. Comparative Example 3. D 50 =4㎛ and Ni 0.83 Co 0.10 Mn 0.07 having the composition of O Precursor oxide and D 50 =10㎛ and anhydrous LiOH was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and the center speed was 400 rpm and mixed for 20 minutes. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni 0.83Co 0.10 Mn 0.07 ]A lithium transition metal oxide having a composition of O2 was prepared. Comparative Example 4. D 50 =4㎛ and Ni 0.83 Co 0.10 Mn 0.07 having the composition of O Precursor oxide and D 50 =100㎛ and anhydrous LiOH was added to a Henschel mixer (700L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and the center speed was 400 rpm and mixed for 20 minutes. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni 0.83 Co 0.10 Mn 0.07 ]A lithium transition metal oxide having a composition of O2 was prepared. Comparative Example 5. D 50 =4㎛ and Ni 0.70 Co 0.20 Mn 0.10 having the composition of O Precursor oxide and D 50 =20㎛ and anhydrous LiOH was added to a Henschel mixer (700 L) so that the final Li / (Ni+Co+Mn) molar ratio was 1.03, and the center speed was 400 rpm and mixed for 20 minutes. The mixture was placed in an alumina crucible measuring 330 mm × 330 mm and heat-treated at 750°C for 12 hours in an oxygen (O2) atmosphere to obtain Li[Ni 0.70 Co 0.20 Mn 0.10 ]A lithium transition metal oxide having a composition of O2 was prepared. [Experimental Example] Experimental Example 1. D 50 Calculating ratios and loss rates (1) Raw material D 50 ratio D of the precursor used in the above examples 1 to 2 and comparative examples 1 to 5 50 D of lithium raw materials for 50 The ratio was calculated and recorded in Table 1 below. (2) Loss rate In the above Examples 1 to 2 and Comparative Examples 1 to 5, the raw material loss rate was calculated according to the above Equation 3 and is shown in Table 1 below. However, in the case of Comparative Examples 1 and 2, the input weight of the precursor hydroxide was substituted instead of the input weight of the precursor oxide in Equation 3, and the input weight of the aqueous lithium raw material was substituted instead of the input weight of the anhydrous lithium raw material. Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Lithium raw material D 50 / Precursor D 50 511.1552.5255 Loss rate (%) 0.951.0227.3829.123.283.411.05 Looking at the results in Table 1 above, it can be confirmed that the raw material loss rate is significantly high in Comparative Examples 1 and 2, which used LiOH as a lithium raw material. In addition, even when using an oxide-type precursor and anhydrous LiOH, the D of the precursor is the same as in Comparative Examples 3 and 4. 50 D of lithium raw materials for 50 It can be confirmed that the raw material loss rate is higher compared to Examples 1 and 2 when the ratio is less than 4 or more than 20. Experimental Example 2. Characteristic Evaluation of Positive Electrode Active Materials The photographs of each positive electrode active material manufactured in Examples 1 to 2 and Comparative Examples 1 to 5 observed with a scanning electron microscope (SEM) are shown in FIGS. 1 to 6, respectively. In addition, the characteristics of each positive electrode active material were evaluated as in (1) to (6) below and are listed in Tables 2 and 3. (1) D 50 After dispersing 0.04 g of each of the positive electrode active material powders manufactured in the above Examples 1 to 2 and Comparative Examples 1 to 5 in a dispersion medium, the powder was introduced into a laser diffraction particle size measuring device (Malvern, Mastersizer 3000) and irradiated with ultrasonic waves of about 28 kHz at an output of 60 W, the D of each positive electrode active material was measured. 50 was measured. (2) Crystal strain and cation mixing ratio The XRD data obtained by performing X-ray diffraction analysis on each of the positive electrode active material powders manufactured in Examples 1 to 2 and Comparative Examples 1 to 5 was analyzed using the Rietveld refinement method to measure the degree of crystal deformation, and the cation mixing ratio was obtained using the excess value of Ni confirmed after Rietveld refinement. At this time, the 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. The sample was placed in the groove of a general powder holder, the sample surface was leveled using a slide glass, and the sample was filled so that the height of the sample matched the edge of the holder. The analysis was performed under the conditions of FDS 0.5°, 2θ=15° to 90°, step size=0.02°, and total scan time=approximately 20 minutes. Rietveld refinement was performed on the measured data considering the charge at each site (metals at transition metal sites are +3, Ni at Li sites is +2) and cation mixing. Instrumental broadening was performed using the Fundamental Parameter Approach (FPA) implemented in the Bruker TOPAS program, and the entire peaks of the measurement range were used for fitting. The peak shape was fitted using only the Lorenzian contribution as the FP (First Principle) among the peak types available in TOPAS. (3) Differential occurrence rate The positive electrode active material powders manufactured in Examples 1 to 2 and Comparative Examples 1 to 5 were placed in a cylindrical metal mold with a diameter of 13 mm and pressed with a force of 12 tons. These were dispersed again in a dispersion medium, and a volume cumulative particle size distribution (PSD) was obtained using a laser diffraction particle size measuring device (Malvern, Mastersizer 3000). Based on the obtained PSD, the volume ratio of fine particles with a particle diameter of 1 μm or less among the total positive electrode active material powder was calculated, and this was recorded as the fine particle generation rate in Table 2 below. (4) Single particle magnetization Each of the positive electrode active material powders manufactured in Examples 1 to 2 and Comparative Examples 1 to 5 was mixed with carbon black and PVDF binder in a weight ratio of 95:2:3 in N-methylpyrrolidone to prepare an electrode slurry. The electrode slurry was applied to one surface of an aluminum current collector and then dried at 130°C to prepare an electrode for EBSD analysis. Rolling was not performed during the manufacture of the positive electrode. The anode was cross-sectioned using an ion milling device (HITACHI IM-5000, accelerating voltage 6 kV), and EBSD analysis was performed on the cross-section of the anode using a FE-SEM (JEOL JSM7900F) equipped with a backscatter electron diffraction pattern analyzer (EBSD). The EBSD analysis was performed at an accelerating voltage of 15 kV, a WD of 15 mm, and a scale with a total number of grains of approximately 400+ / -10. Through EBSD analysis, the longest axis diameters of grains in each particle observed in each anode cross-section were measured, and half of these were calculated as the grain radius, and the arithmetic mean of these was calculated as the average grain diameter. In addition, the grain radius and D measured in (1) above were calculated. 50 The single particle magnetization degree was calculated by substituting it into Equation 2 above. D 50 [㎛] Crystal strain (S) [×10 -6 ]Cation mixing ratio (P) [at%]Substituted in Equation 1 Differential generation rate [vol%]Average grain diameter [㎛]Single particle magnetization Example 14.22751.2P<1.900.851.493.22 Example 24.52631.0P<1.830.921.443.32Comparative example 14.14102.8P>1.274.361.401.65Comparative example 23.42952.4P>1.771.801.152.35Comparative example 33.33302.7P>1.581.441.232.80Comparative example 42.82952.3P>1.771.691.182.44Comparative example 53.83701.44P<1.623.201.302.57 (5) Residual lithium amount Each 5 g of the positive electrode active material powder manufactured in Examples 1 to 2 and Comparative Examples 1 to 5 was dispersed in 100 mL of water, and the pH value change was measured while titrating with 0.1 M HCl to obtain a pH titration curve. Using the pH titration curve, the residual LiOH and residual Li2CO3 amounts relative to the total weight of each positive electrode active material were calculated, and the sum of these values ​​was described as the residual lithium amount. Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Li2CO3 Residual Amount [wt%] 0.277 0.23 20.44 30.35 20.31 00.41 40.26 2 LiOH Residual Amount [wt%] 0.149 0.15 50.20 80.19 50.20 90.24 10.13 4 Lithium Residual Amount [wt%] 0.42 60.38 70.65 10.54 70.52 0.65 50.396 Experimental Example 2. Coin Cell Performance Evaluation (1) Manufacturing of anode The positive electrode active material, conductive agent (carbon black), and binder (PVdF) prepared in Example 1 were added to N-methyl-2-pyrrolidone (NMP) at a weight ratio of 95:2:3 to prepare a positive electrode slurry having a solid content of 60 wt%. The positive electrode slurry was applied to a 15 μm thick aluminum (Al) thin film as a positive electrode current collector to a thickness of 45 μm, dried, and then roll pressed to obtain a loading of 2.8 mAh / cm. 2 A positive electrode was manufactured. In the same manner, positive electrodes using the positive electrode active materials manufactured in Example 2 and Comparative Examples 1 to 5 were also manufactured. (2) Manufacturing of coin half-cells Each positive electrode manufactured in (1) above was assembled with a lithium metal negative electrode to manufacture a coin half-cell. Specifically, an electrode assembly was manufactured by interposing a 15㎛ thick polyethylene separator between the positive and negative electrodes, and then positioning this inside a coin-type (2032 type) secondary battery case, and then injecting an electrolyte into the case to complete the half-cell. At this time, the electrolyte used was 1M LiPF6 dissolved in a mixed organic solvent of ethylene carbonate (EC): ethyl methyl carbonate (EMC) in a volume ratio of 1:2. (3) High temperature life evaluation For each half-cell manufactured in the above (2), an activation (formation) process was performed, and then the PNE-0506 charger / discharger (manufacturer: PNE Solution Co., Ltd.) was used to charge the battery under CC-CV conditions at 0.5C (reference capacity 1C = 200 mAh / g) at 45°C to 4.25 V, and CC discharged at 1.0C to 2.5 V. This charge / discharge cycle was considered one cycle, and the initial discharge capacity was measured after one cycle, and then the discharge capacity was measured while repeating the same charge / discharge cycle for 50 cycles. Based on this, the capacity retention rate compared to the initial discharge capacity was calculated, and the results are shown in Table 4 below. (4) Gas generation evaluation For each half-cell manufactured in the above (2), an activation (formation) process was performed, and then the PNE-0506 charger / discharger (manufacturer: PNE Solution Co., Ltd.) was used to charge the battery under CC-CV conditions at 0.5C (standard capacity 1C = 200 mAh / g) at 45°C to 4.25 V, and CC discharged at 1.0C to 2.5 V. After storage in a chamber at 60°C, the half-cells were taken out of the chamber at weekly intervals and the volume change was calculated using a hydrometer (MATSUHAKU, TWD-150DM) by applying the Archimedes principle. The volume change after 12 weeks was divided by the weight of the positive electrode active material, and the results of calculating the gas generation per weight are shown in Table 4 below. Capacity retention rate [%] Gas generation amount [mL / g] Example 194.4 0.22 Example 293.9 0.27 Comparative example 189.10.44 Comparative example 291.10.35 Comparative example 392.0 0.29 Comparative example 491.8 0.27 Comparative example 591.0 0.47 Looking at the results in Tables 2 to 4 above, when using oxide precursors with nickel content of 80 mol% or more and anhydrous LiOH, their D L / D P In Examples 1 and 2, where the crystal deformation and cation mixing ratio were controlled to 4 to 20, a positive electrode active material satisfying the above formula 1 was manufactured, and the positive electrode active material was D 50 It can be confirmed that the grain diameter is large, the degree of single particle size is high, and the rate of fine particle generation is low. In addition, it can be confirmed that the positive electrode active material contributes to improving the capacity retention rate of a lithium secondary battery and reducing the amount of gas generated. On the other hand, in Comparative Examples 1 and 2 using a hydroxide precursor and LiOH, a positive electrode active material was produced that did not satisfy Equation 1, and it was confirmed that this positive electrode active material had a lower cell performance improvement effect than the examples. In particular, in Comparative Example 2, it was confirmed that a positive electrode active material was produced that had all characteristics, including single particle size, that were worse than those of the examples, despite the fact that the sintering temperature was higher than that of the examples. In addition, even when using oxide precursor and anhydrous LiOH, D as in Comparative Example 3 L / D P If it is less than 4 or as in Comparative Example 4, D L / D P If this exceeds 20, a positive electrode active material that does not satisfy the above formula 1 is manufactured, and it can be confirmed that these also have poor particle characteristics and cell performance improvement effects compared to the positive electrode active material of the example. Meanwhile, through comparative example 5, the D of these was obtained by using oxide precursors and anhydrous LiOH. L / D PEven if a positive electrode active material satisfying Equation 1 is manufactured by controlling the nickel content to 4 to 20, it can be confirmed that the effect of improving particle characteristics and cell performance is poor when the nickel content is less than 80 mol%. In other words, it can be seen that in a positive electrode active material with a nickel content of less than 80 mol% among metals other than lithium, whether Equation 1 is satisfied or not does not represent the particle characteristics and electrochemical performance.

Claims

1. Contains a single particle lithium transition metal oxide having a nickel content of 80 mol% or more among metals other than lithium and consisting of 1 to 30 nodules; A cathode active material having a cation mixing ratio (P) satisfying the following equation 1: [Formula 1] In the above equation 1, P is the cation mixing ratio value of the positive electrode active material, X is the content value of nickel among metals other than lithium in the above lithium transition metal oxide, The above cation mixing ratio is measured in at%, the nickel content is measured in mol%, but P and X are unitless numbers excluding units. S is 10 for the crystal strain 6 It is the product of .

2. In claim 1, D of the above positive electrode active material 50 A positive electrode active material having a diameter of 3.0㎛ to 6.0㎛.

3. In claim 1, The above lithium transition metal oxide is a positive electrode active material having a composition of the following chemical formula 1: [Chemical Formula 1] Li 1+x (Ni a Co b M 1 c M 2 d )O2 In the above chemical formula 1, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0≤x≤0.50, 0.80≤a≤1, 0≤b≤0.20, 0≤c≤0.20, 0≤d≤0.10, a+b+c+d=1.

4. In claim 1, A positive electrode active material having a cation mixing ratio of the positive electrode active material of 2.0 at% or less.

5. In claim 1, A positive electrode active material, wherein when the positive electrode active material is pressurized with a force of 12 tons, the generation rate of fine particles having a particle size of 1㎛ or less is 2.0 vol% or less based on the total volume of the positive electrode active material.

6. In claim 1, The above positive electrode active material is a positive electrode active material having a single particle magnetization degree of 3.0 or more and 4.5 or less according to the following formula 2: [Formula 2] In the above equation 2, R i is the radius value of the i-th grain measured when the electrode manufactured by applying the above positive electrode active material is subjected to ion milling treatment and then the electrode is analyzed by backscatter electron diffraction (EBSD). The radius of the above grain is measured in μm, but Ri is a unitless number excluding the unit. n is the total number of grains measured through the above EBSD analysis, which is 350 to 450.

7. In claim 1, The above positive electrode active material contains LiOH and Li2CO3 on the particle surface, A cathode active material, wherein the total weight of LiOH and Li2CO3 is 0.50 wt% or less relative to the total weight of the cathode active material.

8. A first step of preparing a mixture by mixing a transition metal precursor oxide having a nickel content of 80 mol% or more among the total metal and anhydrous lithium raw material; A second step of producing a single particle lithium transition metal oxide composed of 1 to 30 nodules by calcining the above mixture, D of the above transition metal precursor oxide 50 D of the above anhydrous lithium raw material 50 A method for manufacturing a positive electrode active material, wherein the ratio of the positive electrode active material is 4 or more and 20 or less.

9. In claim 8, A method for manufacturing a positive electrode active material, wherein the above transition metal precursor oxide has a composition represented by the following chemical formula 2: [Chemical Formula 2] Ni a1 Co b1 M 1 c1 M 2 d1 O In the above chemical formula 2, M 1 is Mn, Al or a combination thereof, M 2 is at least one selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, 0.80≤a1≤1, 0≤b1≤0.20, 0≤c1≤0.20, 0≤d1≤0.10, a1+b1+c1+d1=1.

10. In claim 8, D of the above transition metal precursor oxide 50 A method for producing a positive electrode active material having a diameter of 3㎛ to 6㎛.

11. In claim 8, D of the above anhydrous lithium raw material 50 A method for producing a positive electrode active material having a diameter of 12㎛ to 60㎛.

12. In claim 8, A method for producing a positive electrode active material, wherein the sintering in the second step is performed at 650°C to 900°C.

13. In claim 8, A method for manufacturing a positive electrode active material having a raw material loss rate of 5 wt% or less according to the following formula 3: [Formula 3] [1-{Weight of manufactured lithium transition metal oxide / (Input weight of transition metal precursor oxide + Input weight of anhydrous lithium raw material)}] × 100(%) 14. A positive electrode comprising the positive electrode active material of claim 1.

15. A lithium secondary battery comprising: a positive electrode according to claim 14; a negative electrode including a negative electrode active material; a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

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