Positive electrode material powder, and positive electrode and lithium secondary battery comprising same

Abstract

The present invention relates to a positive electrode material powder, and a positive electrode and a lithium secondary battery including the positive electrode material powder. The positive electrode material powder includes a lithium nickel-based oxide having a nickel content of 80 mol% or more with respect to the total amount of metals other than lithium, has a D50 of 4 µm or more, and has a degree of single-particle formation represented by Equation (I) of 35-60%. In the equation, A (in µm2) is the median value of the primary particle area of the positive electrode material powder measured by SEM image analysis, and D50 (in µm) is the volume-based cumulative average of the positive electrode material powder measured by a particle size analyzer.

Description

Cathode material powder, a cathode containing the same, and a lithium secondary battery

[0001] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0199364 filed on December 27, 2024 and Korean Patent Application No. 10-2025-0198224 filed on December 12, 2025, and all contents disclosed in said Korean patent application documents are incorporated herein as part of the specification.

[0002] The present invention relates to a cathode material powder for a lithium secondary battery, a cathode containing the same, and a lithium secondary battery.

[0003] As industries utilizing lithium-ion batteries, such as mobile phones, laptop computers, and electric vehicles, grow rapidly, active research and development efforts are underway to improve their performance. Lithium-ion batteries generate electrical energy through oxidation and reduction reactions when lithium ions are inserted into and extracted from the positive and negative electrodes. For example, lithium ions from the positive electrode move to the negative electrode to charge the battery, while lithium ions from the negative electrode return to the positive electrode to release energy and discharge.

[0004] Rechargeable batteries generally consist of four core components: a positive electrode, a negative electrode, a separator, and an electrolyte. These components interact organically to repeatedly charge and discharge, storing and releasing energy. Furthermore, the positive and negative electrodes of a rechargeable battery are the core electrodes where oxidation-reduction reactions occur; the positive electrode performs oxidation (ion release), while the negative electrode performs reduction (ion storage). Generally, the positive and negative electrodes determine the battery's performance, while the electrolyte and separator determine its safety. Meanwhile, the positive and negative electrodes of a rechargeable battery contain positive and negative active materials, respectively; the positive active material determines the capacity and voltage of the battery, while the negative active material generates electrical energy by storing and releasing lithium ions.

[0005]

[0006] The present invention provides a cathode material powder for a lithium secondary battery that has a high nickel content, relatively low gas generation during electrode manufacturing, easy slurry processability, and excellent high-temperature stability by controlling the particle size and primary particle size of the cathode material powder.

[0007] In addition, the present invention provides a positive electrode and a lithium secondary battery having excellent capacity characteristics, lifespan characteristics, and high-temperature stability by including the above-mentioned positive electrode powder.

[0008]

[0009] [1] The present invention comprises a lithium nickel-based oxide having a nickel content of 80 mol% or more among metals other than lithium, and D 50 The present invention provides an anode powder having a particle size of 4 μm or more and a single particle size of 35% to 60% as indicated by the following formula (1).

[0010] Equation (1)

[0011]

[0012] In the above equation (1), A is (unit: μm 2 ) is the median of the primary particle area of ​​the above cathode material powder measured through SEM image analysis, and D 50 (Unit: μm) is the cumulative average volume of the above-mentioned cathode material powder measured through a particle size analyzer.

[0013] [2] The present invention provides an anode powder according to [1], wherein the anode powder comprises a single particle consisting of one primary particle or a pseudo-single particle form consisting of 50 or fewer primary particles.

[0014] [3] The present invention provides a cathode material powder, wherein, in [1] or [2], the lithium nickel-based oxide has the composition of [Chemical Formula 1] below.

[0015] [Chemical Formula 1]

[0016] Li x [Ni a Co bM 1 c M 2 d ]O2

[0017] In the above [Chemical Formula 1], M 1 is Mn, Al, or a combination thereof, and M 2 ... comprises one or more selected from the group consisting of Zr, W, Ti, Mg, Ba, Ca, Ta, Nb, and Mo, and 0.8≤x≤1.2, 0.7≤a<1.0, 0 <b<0.3, 0<c<0.3, 0≤d<0.1이다.

[0018] [4] The present invention is, in at least one of [1] to [3], of the formula (1). The provides a cathode material powder having a thickness of 1 μm to 4 μm.

[0019] [5] The present invention provides a cathode material powder in which the tap density of the cathode material powder is 1.80 g / cc or more, in at least one of [1] to [4].

[0020] [6] The present invention provides an anode powder having a rolled density of 3.50 g / cc or more, measured after pressing to 9 ton, in at least one of [1] to [5].

[0021] [7] The present invention provides a cathode material powder comprising, in at least one of [1] to [6], a coating layer comprising one or more coating elements selected from Al, Ti, W, B, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si and S on the surface of the lithium nickel-based oxide.

[0022] [8] The present invention is, in at least one of [1] to [7], the D of the anode material powder 50 This provides a cathode material powder with a thickness of 4 μm to 7 μm.

[0023] [9] The present invention provides a positive electrode for a lithium secondary battery comprising a positive electrode powder according to at least one of [1] to [8].

[0024]

[0010] The present invention provides a lithium secondary battery comprising the positive electrode of [9].

[0025]

[0026] The cathode material powder according to the present invention is a cathode material powder comprising a high-nickel (High-Ni) lithium nickel-based oxide, satisfying a single particle size degree represented by the above formula (1) in the range of 35% to 60%, and D 50 By maintaining this at 4 μm or more, the tap density and rolling density are excellent, the amount of gas generated is low, and the high temperature stability is excellent.

[0027] In addition, the positive electrode for a lithium secondary battery and the lithium secondary battery according to the present invention can achieve excellent high-temperature stability, lifespan characteristics, and capacity characteristics by including a high-nickel positive electrode powder having excellent rolling density and low gas generation.

[0028]

[0029] The following drawings attached to this specification illustrate embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0030] FIG. 1 illustrates a method for manufacturing a cathode material powder according to one embodiment of the present invention.

[0031] FIG. 2 is a diagram showing the structure of an anode manufactured using anode material powder according to one embodiment of the present invention.

[0032] FIG. 3 is a diagram showing the structure of a secondary battery manufactured by applying a cathode manufactured using cathode material powder according to one embodiment of the present invention.

[0033] In parts of the attached drawings, corresponding components are given the same reference numerals. Those skilled in the art understand that the drawings are intended to illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to aid in understanding various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated compared to others. Additionally, elements of known technology that are useful or essential in commercially viable embodiments may often be omitted so as not to hinder the spirit of the various embodiments of the present invention.

[0034]

[0035] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0036] The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise.

[0037] In this specification, terms such as “comprising,” “having,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. Furthermore, in this specification, when a part such as a layer, film, region, or plate is described as being formed on another part, the direction in which it is formed is not limited to the upward direction but includes being formed in the lateral or downward direction.

[0038] In the present invention, "primary particle" refers to a particle unit in which no grain boundaries appear when observed at a field of view of 5,000 to 20,000 times using a scanning electron microscope.

[0039] In the present invention, “single particle type” refers to a particle composed of 50 or fewer primary particles, and is a concept that includes “single particle” formed by aggregating 1 primary particle and “pseudo-single particle” particles formed by aggregating 2 to 50 or fewer primary particles.

[0040] In the present invention, "secondary particle" refers to a particle formed by the aggregation of tens to hundreds of multiple primary particles. For example, a secondary particle refers to an aggregate of 51 or more primary particles.

[0041] The expression "particle" used in the present invention may include any one or all of single particles, pseudo-single particles, primary particles, and secondary particles.

[0042] In the present invention, "D 50 " refers to the particle size at the 50% standard of the volume cumulative particle size distribution of the positive active material. The above D 50 It can be measured using the laser diffraction method. For example, after dispersing the positive active material powder in a dispersion medium, it can be introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiated with ultrasound of about 28 kHz at an output of 60 W, and then measured by determining the particle size corresponding to 50% of the volume accumulation.

[0043] In the present invention, the "specific surface area" is measured by the BET method and can be calculated from the amount of nitrogen gas adsorbed at a liquid nitrogen temperature (77 K) using, for example, BELSORP-mino II from BEL Japan.

[0044] As used herein, “about,” “approximately,” and “substantially” are used to mean a range of values ​​or degrees or approximations thereof, taking into account inherent manufacturing and material tolerances (e.g., ±5%).

[0045] Lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, and lithium iron phosphate compounds have been primarily used as cathode active materials for lithium secondary batteries. Furthermore, as a method to improve the low high-temperature stability while maintaining the excellent reversible capacity of lithium nickel oxide, a lithium composite metal oxide (hereinafter simply referred to as 'NCM oxide') in which a portion of the nickel is substituted with cobalt and manganese has been developed.

[0046] Recently, with the increasing demand for high-output, high-capacity batteries such as those for electric vehicles, active attempts are being made to increase the nickel content in NCM oxides. However, High-Ni NCM oxides have limitations in application as cathode materials because they generate a large amount of gas during high-temperature storage or charge-discharge processes due to significant lattice structural instability caused by cation mixing and oxygen desorption, as well as a high content of residual lithium impurities on the surface.

[0047] Accordingly, a technology for manufacturing single-particle cathode active materials by increasing the temperature during calcination has been proposed. These single-particle cathode active materials have the advantage of having a smaller contact area with the electrolyte compared to conventional secondary particle cathode active materials, resulting in fewer side reactions with the electrolyte, excellent particle strength, and less particle breakage during electrode manufacturing. When applied to batteries, they have the advantages of low gas generation and excellent lifespan characteristics. However, single-particle cathode active materials have a problem in that high-temperature stability decreases as the size of the primary particles within the aggregate increases, so appropriate control is still required.

[0048] Considering these points, the present invention provides an anode powder comprising a high-nickel (High-Ni) lithium nickel-based oxide, which has excellent tap density and rolling density, low gas generation, and excellent high-temperature stability.

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

[0050]

[0051] Single-particle particles have a smaller contact area with the electrolyte compared to secondary particles, resulting in fewer side reactions with the electrolyte. Additionally, because they have excellent particle strength, there is less particle breakage during the electrode manufacturing process, which can contribute to reducing gas generation in lithium secondary batteries. However, when increasing the size of primary particles and the proportion of single-particle particles to overcome the limitation of high-nickel cathode materials generating a large amount of gas, the single-particle particles have the disadvantage that high-temperature stability becomes inferior as the size of the primary particles within the aggregate increases. Therefore, it is important to control the proportion of single-particle particles to obtain a cathode material with excellent high-temperature stability, capacity characteristics, and lifespan characteristics in balance.

[0052] The present invention relates to the average particle size D of the anode material powder. 50 By utilizing the fact that when the primary particle size satisfies a specific relationship, it is possible to increase rolling density while minimizing gas generation and achieving excellent high-temperature characteristics, a cathode material for a lithium secondary battery containing a high-nickel cathode material is provided, which has excellent capacity, excellent high-temperature stability and rolling density, and low gas generation.

[0053]

[0054] The following describes each component constituting the present invention in more detail.

[0055]

[0056] Cathode material powder

[0057] The cathode material powder according to the present invention comprises a lithium nickel-based oxide having a nickel content of 80 mol% or more among metals excluding lithium, and D 50 This is 4 μm or more, and the degree of single particle size represented by the following formula (1) is 35% to 60%. The following formula (1) is an indicator that can select a cathode material powder that has excellent tap density and rolling density, excellent slurry processability, and can ensure capacity characteristics, life characteristics, and high temperature stability above a certain level.

[0058] Equation (1)

[0059]

[0060] In the above equation (1), A is (unit: μm 2 ) It refers to the median value of the primary particle area of ​​the above-mentioned cathode material powder measured through SEM image analysis, for example, the value in the middle when the primary particle areas measured through SEM image analysis are sorted in ascending order.

[0061] Also, D 50 (Unit: μm) refers to the volume cumulative average of the above-mentioned cathode material powder measured through a particle size analyzer, and, for example, refers to the particle size at the point where the volume cumulative amount is 50% in the volume cumulative particle size graph measured through a laser diffraction particle size analyzer.

[0062] According to one embodiment, D of the anode powder 50 ... may be 4.5 μm or larger, more specifically, for example, 5.0 μm or larger, or 5.5 μm or larger. In addition, the cathode material powder is D 50 It may be 7.0 μm or less, for example 6.9 μm or less, or 6.8 μm or less.

[0063] The above-mentioned cathode material powder may include a single particle consisting of one primary particle or a pseudo-single particle which is an aggregate of 50 or fewer primary particles, for example, 2 to 40 or 2 to 30 primary particles.

[0064] The above equation (1) is a value corresponding to the diameter of a circle having the same area as A, which is the median of the primary particle area of ​​the cathode material powder measured through SEM image analysis. is the average particle size D of the cathode material powder 50 It is divided by, and the closer the degree of single particle formation included in the above formula (1) is to 100%, the more single-particle type particles there are in the cathode material powder, and the closer it is to 0%, the more secondary particles there are. According to one embodiment, D 50 When the particle size is 4 μm or larger and the degree of single particle size according to the above formula (1) satisfies 35% to 60%, the particle strength is excellent due to the relatively large particle size, so the amount of gas generated is low and the slurry processability is excellent, and both lifespan characteristics and high temperature stability can be secured to a certain degree.

[0065] According to one embodiment, the degree of single particle formation according to the formula (1) may be 35% or more, for example 36% or more, or 37% or more, and 59% or less, more specifically 58% or less, 57% or less, or 56% or less, or 55% or less, 54% or less, or 53% or less, or 50% or less.

[0066]

[0067] Meanwhile, the above lithium nickel-based oxide may have the composition of [Chemical Formula 1] below.

[0068] [Chemical Formula 1]

[0069] Li x [Ni a Co b M 1 c M 2 d ]O2

[0070] In the above [Chemical Formula 1], M 1 is Mn, Al, or a combination thereof, and M 2... comprises one or more selected from the group consisting of Zr, W, Ti, Mg, Ba, Ca, Ta, Nb, and Mo, and 0.8≤x≤1.2, 0.7≤a<1.0, 0 <b<0.3, 0<c<0.3, 0≤d<0.1이다.

[0071] The above x represents the molar ratio of lithium in the lithium nickel-based oxide, for example, 0.9≤x≤1.2, 0.8≤x≤1.1, or 0.9≤x≤1.1. When the molar ratio of lithium satisfies the above range, the crystal structure can be stably formed.

[0072] The above 'a' represents the molar ratio of nickel among all metals excluding lithium in the lithium nickel-based oxide, and may be, for example, 0.80 ≤ a < 1.00, 0.81 ≤ a < 1.00, or 0.82 ≤ a < 1.00. When the molar ratio of nickel satisfies the above range, high energy density is exhibited, making it possible to realize high capacity.

[0073] The above b represents the molar ratio of cobalt among the total metals excluding lithium in the lithium nickel-based oxide, for example, 0 <b≤0.20, 0<b≤0.18, 또는 0<b≤0.16일 수 있다. 코발트의 몰비가 상기 범위를 만족할 때, 양호한 저항 특성 및 출력 특성을 구현할 수 있다.

[0074] The above c is M among the total metals excluding lithium in the lithium nickel-based oxide. 1 It represents the molar ratio of an element, for example, 0 <c≤0.20, 0<c≤0.18, 또는 0<c≤0.16일 수 있다. 한편, 상기 M 1 It may be Mn; or a combination of Mn and Al, preferably Mn.

[0075] The above d is M among the total metals excluding lithium in the above lithium nickel-based oxide. 2 It represents the molar ratio of the elements, for example, 0≤d≤0.08, 0≤d≤0.05, or 0≤d≤0.03.

[0076]

[0077] Meanwhile, of the above equation (1) It may be 1 μm to 4 μm, for example 1.1 μm to 4 μm, 1 μm to 3.9 μm or 1.1 μm to 3.9 μm, or 1.2 μm to 3.9 μm or 1.2 μm to 3.8 μm, or 1.3 μm to 3.7 μm, or 1.5 μm to 3.5 μm. When the above-described range is satisfied, particle breakage during electrode manufacturing is minimized, and side reactions on the electrode surface can be reduced.

[0078]

[0079] Meanwhile, the tap density of the above-mentioned cathode material powder may be 1.80 g / cc or higher, for example, 1.81 g / cc or higher, 1.82 g / cc or higher, 1.83 g / cc or higher, 1.84 g / cc or higher, or 1.85 g / cc or higher. If the tap density satisfies the above-mentioned range, the energy density can be improved.

[0080] Meanwhile, the above-mentioned cathode material powder may have a rolled density of 3.50 g / cc or more, measured after being pressed to 9 ton, for example, 3.51 g / cc or more, 3.52 g / cc or more, 3.53 g / cc or 3.54 g / cc or more, or 3.55 g / cc or more. If the rolled density satisfies the above-mentioned range, the particle packing can become dense, thereby improving the energy density.

[0081]

[0082] Method for manufacturing cathode material powder

[0083] Hereinafter, a method for manufacturing anode material powder according to the present invention will be described.

[0084] Referring to FIG. 1, a method for manufacturing a cathode material powder according to one embodiment of the present invention comprises the steps of: mixing a precursor having a nickel content of 80 mol% or more with a lithium raw material to prepare a mixture (S10); first calcining the mixture at 750 ℃ ​​to 950 ℃ for 9 to 14 hours (S20); and second calcining the first calcined body at 700 ℃ to 900 ℃ for 9 to 14 hours (S30).

[0085]

[0086] Next, each step is explained.

[0087]

[0088] First, a step (S10) of preparing a mixture by mixing a precursor having a nickel content of 80 mol% or more with a lithium raw material is performed.

[0089] D of the above precursor 50 ... may be 5.5 μm to 9.0 μm, for example, 6.0 μm to 8.5 μm. D of the precursor 50 When satisfying the above-described range, the single-particle degree range of the present invention is satisfied, and D 50 It is possible to manufacture cathode material powder with a thickness of 4.0 μm or more.

[0090] The specific surface area of ​​the above precursor measured by BET (Brunauer, Emmett, Teller) is 1 m² 2 / g to 4 m 2 / g, for example, 1.5 m 2 / g to 3.5 m 2 It can be / g. Since the degree of single-particle formation of the manufactured cathode material powder tends to decrease as the BET value of the precursor increases, if the BET of the precursor is 4 m 2 If it exceeds / g, the degree of single particle size of the cathode material powder may be less than 35%, and 1 m 2 If it is less than / g, the degree of single particle size of the cathode material powder may exceed 60%.

[0091] Meanwhile, the above precursor may be in the form of a hydroxide, an oxide, or a carbonate, for example, in the form of a hydroxide, or may have the composition of the following chemical formula 2.

[0092] [Chemical Formula 2]

[0093] Ni a1 Co b1 M 1 c1 M 2 d1 (OH)2

[0094] In the above chemical formula 2, M 1 is Mn, Al, or a combination thereof, and M 2 comprises one or more selected from the group consisting of Zr, W, Ti, Mg, Ba, Ca, Ta, Nb, and Mo, and 0.7≤a1<1.0, 0 <b1<0.3, 0<c1<0.3, 0≤d1<0.1이다.

[0095] The above “a1” represents the molar ratio of nickel among the total metals in the precursor, and may be, for example, 0.80≤a1<1.00, 0.81≤a1<1.00, or 0.82≤a1<1.00.

[0096] The above “b1” represents the molar ratio of cobalt among the total metals in the precursor, for example, 0 <b1≤0.20, 0<b1≤0.18, 또는 0<b1≤0.16일 수 있다.

[0097] The above “c1” is M among the total metals in the precursor. 1 It represents the molar ratio of an element, for example, 0 <c1≤0.20, 0<c1≤0.18, 또는 0<c1≤0.16일 수 있다.

[0098] The above d1 is M among the total metals in the precursor. 2 It represents the molar ratio of the elements, for example, 0≤d1≤0.08, 0≤d1≤0.05, or 0≤d1≤0.03.

[0099] The above precursor may be purchased and used as a commercially available precursor, or it may be manufactured and used according to a precursor manufacturing method known in the relevant technical field.

[0100] Meanwhile, as the above lithium raw material, lithium-containing sulfates, nitrates, acetates, carbonates, oxalates, citrates, halides, hydroxides, or oxyhydroxides may be used, for example, Li2CO3, LiNO3, LiNO2, LiOH, LiOH·H2O, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7, or mixtures thereof may be used.

[0101] The above lithium raw material and precursor can be mixed such that the molar ratio of Li to total metal in the precursor is 0.8:1.0 to 1.2:1.0, for example, 0.9:1.0 to 1.1:1.0. 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 nickel-based oxide is well developed, and a cathode material with excellent capacity characteristics and structural stability can be manufactured.

[0102]

[0103] Next, a step of preparing a sintered body by calcining the above mixture is performed. According to one embodiment, the calcination includes a first calcination and a second calcination, and the first calcination may be performed by calcining the mixture under an oxygen atmosphere at 750°C to 950°C, for example, 800°C to 900°C, or at 850°C to 900°C for 9 to 14 hours. The first calcination is a step of increasing the structural completeness of the lithium nickel-based oxide and making it single-particle, and considering that the higher the calcination temperature, the better the particle growth reaction proceeds and the higher the degree of single-particle formation, it may be performed at 750°C or higher according to one embodiment. However, considering that if under-calcination occurs during the first calcination, the reactivity between the precursor and the lithium raw material decreases, and that if the content of Li2O increases due to high-temperature calcination, it is easily converted to LiOH, and LiOH is easily converted again to Li2CO3, which can cause side reactions with the electrolyte and gas generation, the process may be carried out at 950°C or lower according to one embodiment. Here, an oxygen atmosphere refers to an atmosphere containing a sufficient amount of oxygen for calcination, including an atmospheric atmosphere. Generally, the process is carried out in an atmosphere where the partial pressure of oxygen is higher than that of an atmospheric atmosphere.

[0104] The above second firing may be performed on the above first-fired sintered body in an oxygen atmosphere at 700°C to 900°C, for example, 770°C to 870°C, or 780°C to 820°C. The above second firing may be performed for 9 to 14 hours, for example, 10 to 14 hours, or 11 to 13 hours. Since the second firing is performed to increase the degree of single-grain formation, the temperature of the second firing is carried out at 700°C or higher; however, considering that strain and cation mixing ratio may increase if the firing temperature is excessively high, it is generally carried out at 900°C or lower.

[0105] After the second firing, a step (S40) of milling the fired body may be performed. Specifically, the step of milling the second fired fired body at a speed of 1,000 rpm to 2,500 rpm, preferably 1,200 rpm to 2,300 rpm may be further included.

[0106] According to one embodiment, milling may be performed in a pressure range of 2.0 bar to 4.0 bar, 2.2 bar to 3.8 bar, or 2.4 bar to 3.5 bar. Since the particle size tends to decrease as the milling pressure increases, when the milling pressure satisfies the above-described range, an anode material powder satisfying the single-particle degree range of the present invention can be produced.

[0107] The above milling process is intended to remove large particles and obtain the particle size of the cathode material powder within a desired numerical range. During the above high-temperature firing process, aggregation and / or clumping between adjacent particles may occur, resulting in the formation of large particles, which leads to a deterioration in rolling characteristics. Therefore, in the present invention, by performing a milling process, large particles are removed and finally the aforementioned D 50 It is possible to form an anode powder having the above.

[0108] The above milling may be performed using a general milling method known in the art, for example, a jet-mill method, and the speed refers to the classifier speed.

[0109] According to one embodiment, the milling is performed in a low-moisture atmosphere, for example, a dry air atmosphere. This is because exposure of the lithium nickel-based oxide to moisture can increase the generation of lithium byproducts and degrade the surface properties of the active material.

[0110]

[0111] anode

[0112] Next, the anode of the present invention will be described.

[0113] Referring to FIG. 2, according to another embodiment of the present invention, an anode (10) comprising the anode material powder is provided.

[0114] The anode according to the present invention comprises an anode active material layer (14) comprising the anode material powder according to the present invention described above on an anode current collector (12), and the anode active material layer (14) may further comprise an anode conductive material and an anode binder as needed. For example, the anode (10) comprises an anode current collector (12) and an anode active material layer (14) formed on at least one surface of the anode current collector (12), and the anode active material layer (14) comprises an anode active material, an anode conductive material, and an anode binder. Meanwhile, since the anode material powder is the same as described above, further explanation is omitted, and components excluding the anode material powder are described below.

[0115]

[0116] In the above positive electrode (10), the positive electrode current collector (12) is not particularly limited as long as it is conductive without causing chemical changes in the battery, and for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. may be used. In addition, the positive electrode current collector may typically have a thickness of 3 μm to 500 μm, and fine irregularities may be formed on the surface of the positive electrode current collector to increase the adhesion 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, nonwoven body, etc.

[0117]

[0118] According to one embodiment, the cathode material powder may be included in an amount of 90% to 99% by weight, for example 93% to 99% by weight, or 95% to 98% by weight, based on the total weight of the cathode active material layer, i.e., the total amount of the sum of the cathode material powder, the cathode conductive material, and the cathode binder. When the content of the cathode active material satisfies the above range, a relatively high energy density can be achieved.

[0119]

[0120] The above-mentioned positive electrode conductive material is used to impart conductivity to the positive electrode (10), and in the battery being constructed, any material that has electronic conductivity without causing chemical changes can be used without special limitations. Examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, carbon fiber, carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more of these may be used.

[0121] The above positive conductive material may be included in an amount of 0.1% to 10% by weight, for example, 0.5% to 8% by weight, or 1% to 5% by weight based on the total weight of the positive active material layer (14).

[0122] The above-mentioned anode binder serves to improve adhesion between anode active material particles and adhesion between the anode active material and the anode current collector. Examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, 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 alone or a mixture of two or more may be used.

[0123] The above anode binder may be included in an amount of 0.5% to 5% by weight, for example, 1% to 4% by weight, or 1% to 3% by weight based on the total weight of the anode active material layer (14).

[0124]

[0125] The anode (10) can be manufactured according to a conventional anode manufacturing method. For example, the anode (10) can be manufactured by mixing an anode material powder, an anode binder, and / or an anode conductive material in a solvent to produce an anode slurry, applying the anode slurry onto an anode current collector (12), and then drying and rolling, or by casting the anode slurry onto a separate support and then laminating the film obtained by peeling off from the support onto the anode current collector (12).

[0126] Meanwhile, solvents commonly used in the relevant technical field may be used as solvents for the anode slurry; for example, dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, water, etc., may be used individually or as a mixture of two or more. The amount of the solvent used is sufficient if it has a viscosity that dissolves or disperses the anode active material, conductive material, and binder, taking into account the coating thickness and manufacturing yield of the slurry, and provides excellent thickness uniformity when applied for anode manufacturing thereafter.

[0127]

[0128] lithium secondary battery

[0129] Next, a secondary battery according to the present invention will be described.

[0130] Referring to FIG. 3, according to another embodiment of the present invention, a lithium secondary battery (100) including the positive electrode is provided.

[0131] A lithium secondary battery (100) according to one embodiment of the present invention comprises: a positive electrode (10) according to the present invention; a negative electrode (20) disposed opposite to the positive electrode (10); a separator (30) and an electrolyte (40) interposed between the positive electrode (10) and the negative electrode (20). Additionally, a lithium secondary battery (100) according to one embodiment of the present invention comprises an electrode assembly consisting of the positive electrode (10), the negative electrode (20), and the separator (30), and a battery case (50) accommodating the electrolyte (40).

[0132] The lithium secondary battery (100) according to one embodiment of the present invention has excellent lifespan characteristics with low gas generation, as well as excellent capacity characteristics and high-temperature stability. Since the lithium secondary battery (100) exhibits stable high-temperature performance, it can be used as a battery cell for power sources in small devices such as mobile phones, laptop computers, and digital cameras, and can also be preferably used as a unit cell for a battery module for medium-to-large devices comprising a plurality of battery cells. Examples of medium-to-large devices include power tools, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, and power storage systems, but are not limited thereto.

[0133]

[0134] In the above lithium secondary battery, the negative electrode (20) comprises a negative electrode (20) including a negative electrode active material, a negative electrode conductive material, and a negative electrode binder. For example, the negative electrode (20) comprises a negative electrode current collector and a negative electrode active material layer formed on at least one surface of the negative electrode current collector, wherein the negative electrode active material layer comprises a negative electrode active material, a negative electrode conductive material, and a negative electrode binder.

[0135] The above-mentioned negative current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy may be used. In addition, the above-mentioned negative current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive current collector, fine irregularities may be formed on the surface of the current collector to strengthen the bonding strength of the negative active material. For example, it may be used in various forms such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0136] As the above-mentioned cathode 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; metal oxides capable of doping and dedoping lithium such as SiOβ (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the above-mentioned metallic compounds and carbonaceous materials such as Si-C composites or Sn-C composites, and any one or more of these may be used.

[0137] The above-mentioned negative electrode active material may be included in an amount of 80% to 98% by weight, for example, 90% to 98% by weight, or 93% to 98% by weight, based on the total weight of the negative electrode active material layer. When the content of the negative electrode active material satisfies the above range, excellent energy density can be achieved.

[0138] The above-mentioned cathode conductive material is used to impart conductivity to the cathode (20), and in the battery (100) configured therein, any material that has electronic conductivity without causing chemical changes can be used without special limitations. Examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, Super C, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, carbon fiber, carbon nanotube; metal powder or metal fiber such as copper, nickel, aluminum, silver; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more types may be used.

[0139] The above-mentioned cathode conductive material may typically be included in an amount of 0.1% to 10% by weight, for example, 0.5% to 8% by weight, or 0.8% to 5% by weight, based on the total weight of the cathode active material layer.

[0140] The above-mentioned cathode binder serves to improve adhesion between cathode active material particles and adhesion between the cathode active material and the cathode current collector. Examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, 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 alone or a mixture of two or more may be used.

[0141] The above-mentioned cathode binder may be included in an amount of 1% to 10% by weight, for example, 1% to 8% by weight, or 1% to 5% by weight, based on the total weight of the positive active material layer.

[0142]

[0143] In the above lithium secondary battery (100), the electrolyte (40) may include an organic solvent and a lithium salt.

[0144] The above-mentioned organic solvent may be used without special restrictions as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. For example, the above-mentioned organic solvent may include ester-based solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether-based solvents such as dibutyl ether or tetrahydrofuran; ketone-based solvents such as cyclohexanone; and aromatic hydrocarbon-based solvents such as benzene and fluorobenzene. Carbonate-based solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having C2 to C20 structures and may include a double bond, a directional ring, or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes may be used. Among these, a carbonate-based solvent is preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery, and a low-viscosity linear carbonate-based compound (e.g., ethylmethyl carbonate, dimethyl carbonate or diethyl carbonate, etc.) may be used.

[0145] The above lithium salt can be used without special limitations 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, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. According to one embodiment, the concentration of the lithium salt is preferably used within the range of 0.1 M to 3.0 M, for example, 0.1 M to 2.0 M, or 0.5 M to 1.5 M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0146] In addition to the above electrolyte components, the above electrolyte may additionally include additives for the purpose of improving the lifespan characteristics of the battery, suppressing the reduction of battery capacity, and improving the discharge capacity of the battery. For example, the above additives may include various additives used in the relevant technical field, such as fluoroethylene carbonate (FEC), vinylene carbonate (VC), vinylethylene carbonate (VEC), ethylene sulfate (ESa), lithium difluorophosphate (LiPO2F2), lithium bisoxalatetoborate (LiBOB), lithium tetrafluoroborate (LiBF4), lithium difluorooxalatetoborate (LiDFOB), lithium difluorobisoxalatetophosphate (LiDFBP), lithium tetrafluorooxalatetophosphate (LiTFOP), lithium methyl sulfate (LiMS), lithium ethyl sulfate (LiES), propanesulfone (PS), propensulfone (PRS), succinonitrile (SN), adiponitrile (AND), 1,3,6-hexanedricarbonitrile (HTCN), 1,4-disyano-2-butene (DCB), fluorobenzene (FB), Ethyl di(pro-2-i-1-nyl) phosphate (EDP), 5-methyl-5-propazyloxylcarbonyl-1,3-dioxane-2-one (MPOD), etc. may be used alone or in combination, but are not limited thereto. According to one embodiment, the additive may be included in an amount of 0.1% to 10% by weight, for example, 0.1% to 5% by weight, based on the total weight of the electrolyte.

[0147]

[0148] The above lithium secondary battery (100) may additionally include a separator (30) between the positive electrode and the negative electrode as needed. The separator (30) separates the negative electrode and the positive electrode and provides a passage for the movement of lithium ions. Any separator typically used as a separator in a lithium secondary battery can be used without special limitations, and generally, one that has low resistance to the movement of electrolyte ions and excellent electrolyte moisture retention ability is used. For example, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used. In addition, a coated membrane (30) containing ceramic components or polymer materials may be used to ensure heat resistance or mechanical strength, and may optionally be used in a single-layer or multi-layer structure.

[0149] The above lithium secondary battery (100) includes, as needed, a battery case (50) that accommodates an electrode assembly comprising a positive electrode, a negative electrode, and a separator (30). A battery case (50) according to one embodiment of the present invention may be manufactured in a prismatic type, a pouch type, a coin type, and a cylindrical type, depending on the form in which it is manufactured.

[0150]

[0151] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0152]

[0153] Preparation Example: Preparation of cathode material powder

[0154] Example 1

[0155] The molar ratio of Ni:Co:Mn is 83:11:6, and D is the cumulative volume average measured by a particle size analyzer. 50 This is 7.5 µm, and the specific surface area measured by the BET method is 2.5 m² 2 Nickel-cobalt-manganese hydroxide powder as a precursor in g and lithium hydroxide were mixed such that the molar ratio of Li to transition metal (Ni+Co+Mn) was 1.05:1.00, then first calcined at 870 °C for 12 hours and secondly calcined at 800 °C for 12 hours. Afterward, the calcined product was ground in a jet mill at a gas pressure of 3 bar and a rotation speed of 2000 rpm to produce cathode material powder.

[0156]

[0157] Example 2

[0158] D 50 It is 9.0 µm, with a specific surface area of ​​2.5 m² 2 A cathode material powder was prepared in the same manner as in Example 1, except that nickel-cobalt-manganese hydroxide powder with a content of 1 / g was used as a precursor.

[0159]

[0160] Comparative Example 1

[0161] Specific surface area is 5.0 m² 2 A cathode material powder was prepared in the same manner as in Example 1, except that nickel-cobalt-manganese hydroxide powder with a content of 1 / g was used as a precursor.

[0162]

[0163] Comparative Example 2

[0164] D 50 It is 9.0 µm, with a specific surface area of ​​2.5 m² 2A cathode material powder was prepared in the same manner as in Example 1, except that nickel-cobalt-manganese hydroxide powder with a content of 1 / g was used as a precursor and first calcined at 900°C for 15 hours.

[0165]

[0166] Comparative Example 3

[0167] D 50 It is 5.0 µm, with a specific surface area of ​​6.0 m² 2 A cathode material powder was prepared in the same manner as in Example 1, except that nickel-cobalt-manganese hydroxide powder with a content of 1 / g was used as a precursor.

[0168]

[0169] Experimental Example 1. Measurement of Single-Particle Degree

[0170] 1-1. D 50 measurement

[0171] After dispersing 0.1 g of each cathode material powder prepared in Examples 1 and 2 and Comparative Examples 1 to 3 in a dispersion medium, the powder was introduced into a laser diffraction particle size measuring device (Microtrac MT 3000) and irradiated with ultrasound at approximately 28 kHz at an output of 60 W to measure the D of each cathode material powder 50 ...was measured. The measurement results are shown in Table 1 below.

[0172]

[0173] 1-2. Measurement of Primary Particle Area

[0174] In addition, using a scanning electron microscope, SEM images of each cathode material powder prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were obtained, and the area of ​​the primary particles identified in the measured SEM images was measured, and the median value A of the measurements was derived, and then 2(A / π) 1 / 2 The values ​​were calculated and are shown in Table 1 below.

[0175]

[0176] 1-3. Calculation of Single-grain Degree

[0177] The D calculated above50 and 2(A / π) 1 / 2 The single-particle magnetization degree was calculated by substituting the value into Equation (1), and the result is shown in Table 1 below.

[0178] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 2(A / π) 1 / 2 [㎛]2.363.272.024.011.59D 50 [㎛] 5.90 5.5 3.0 4.5 6.5 4.8 2. Degree of particle size [%] 40 50 33 61 42

[0179] Referring to Table 1, D of the cathode material powder of Examples 1 and 2 and Comparative Examples 1 and 2 50 This was found to be 4 μm or more, and in the case of Comparative Example 3, D 50 It was found to be smaller than 4 μm. In addition, the single particle size of Examples 1 and 2 was 40% and 50%, respectively, which is within the range of about 35% to 60%, whereas in Comparative Examples 1 and 2, the single particle size was 33% and 61%, respectively, which is outside the range of about 35% to 60%. However, in Comparative Example 3, the single particle size was 42%, which is within the range of about 35% to 60%.

[0180]

[0181] Experimental Example 2. Evaluation of Powder Characteristics

[0182] 2-1. Measurement of Tap Density

[0183] The tap density of each cathode material powder prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured using a tap density meter (GEOPYC 1360 of Micromeritics). For example, 10 g of each cathode material powder prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was taken and filled into a container with a diameter of 19 mm, and then the tap density was measured by vibrating it until a horizontal force of 108 N was applied, and the results are listed in Table 2 below.

[0184]

[0185] 2-2. Measurement of Rolled Density

[0186] The rolling density of each of the cathode material powders prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured using a density measuring device (Caver Pellet Press). Specifically, 3 g of each of the cathode material powders prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was divided and filled without gaps into a cylindrical holder with a diameter of 13 mm, and then a pressure of 9 ton was applied to measure each rolling density.

[0187] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tap Density [g / cc] 1.92 2.27 1.63 2.38 1.74 Rolled Density [g / cc] 3.63 3.66 3.54 3.67 3.42

[0188] From the results in Table 2 above, it can be seen that Comparative Example 1, with a single particle size degree of less than 35%, has a relatively low tap density, and D of the cathode material powder 50 It can be seen that Comparative Example 3, which is less than 4 μm, has inferior tap density and rolling density even though it satisfies the single-grained degree range.

[0189]

[0190] Experimental Example 3. Battery Performance Evaluation

[0191] 3-1. Manufacture of Monocells

[0192] An anode slurry was prepared by mixing the respective anode powders prepared in Examples 1 to 2 and Comparative Examples 1 to 3, carbon black as a conductive material, and PVDF as a binder in an NMP solvent in a weight ratio of 96.5:1.5:2.0. The prepared anode slurry was applied to one side of an aluminum current collector, dried at 130°C, and then rolled to produce an anode.

[0193] In addition, a cathode slurry was prepared by mixing graphite as the cathode active material, super C as the conductive material, and SBR / CMC as the binder in a weight ratio of 95.6:1.0:3.4, and the slurry was coated on one side of a copper current collector, dried at 130°C, and then rolled to manufacture a cathode.

[0194] An electrode assembly was manufactured by interposing a separator between the anode and the cathode, and then the assembly was placed inside a battery case, and an electrolyte was injected into the case to manufacture a lithium secondary battery monocell. The electrolyte was prepared by dissolving LiPF6 at a concentration of 1 M in a mixed organic solvent in which ethylene carbonate / dimethyl carbonate / diethyl carbonate were mixed in a volume ratio of 1:2:1, and adding 2 wt% of vinylene carbonate (VC).

[0195]

[0196] 3-2. Evaluation of Gas Generation Amount

[0197] For each of the cells manufactured above, a formation process was performed, and then the cells were charged at 25°C with a constant current (CC) of 0.1 C (reference capacity 1 C = 40 mAh / g) until the voltage reached 4.25 V, and then charged with a constant voltage (CV) until the charging current reached 0.05 C (cut-off current). Afterward, the cells were stored in a chamber at 60°C, and at weekly intervals, the cells were removed from the chamber and the change in volume was calculated by applying Archimedes' principle using a hydrometer (MATSUHAKU, TWD-150DM). Based on the results measured over 8 weeks, the average value of the change in volume per week was calculated and listed in Table 3 below.

[0198] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Gas generation amount [㎖] 0.175 0.194 0.255 0.27 0.335

[0199] From the results in Table 3 above, it can be seen that the cells of Examples 1 and 2 have a relatively lower gas generation amount compared to the Comparative Example, and in particular, D of the cathode material powder 50 It can be confirmed that Comparative Example 3, which is less than 4 μm, has a significantly higher amount of gas generated.

[0200]

[0201] 3-3. High Temperature Stability Evaluation

[0202] To evaluate high-temperature stability, the heat flow according to temperature of the anodes prepared in Examples 1 to 2 and Comparative Examples 1 to 3 was measured using a differential scanning calorimeter (Setaram, model name: SENSYS evo DSC).

[0203] For example, the cells of Examples 1 and 2 and Comparative Examples 1 to 3 prepared above were charged at 25°C with a constant current of 0.1 C until they reached 4.25 V, respectively, and then the cells were disassembled to separate the anodes. The separated anodes were washed with dimethyl carbonate, immersed in 20 µL of electrolyte (1M LiPF6, EC:DMC:EMC = 3:4:3 volume ratio), and DSC analysis was performed on the anode active material. The temperature range for DSC analysis was set to 25°C to 400°C, and the heating rate was set to 10°C / min. DSC measurements were performed at least three times for each anode, and the average value was calculated. The measurement results are shown in Table 4 below. Meanwhile, DSC analysis, short for Differential Scanning Calorimetry, is a thermal analysis technique that analyzes the thermal properties (melting point, glass transition temperature, phase change, etc.) of a material by measuring the difference in heat generated when heating or cooling a sample. Through this analysis, various information regarding the physical and chemical reactions and thermal stability of a material can be obtained.

[0204] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 DSC Main Peak Intensity [W / g] 11 13.4 11.2 19.9 10.6

[0205] Referring to Table 4 above, it can be confirmed that the anode of Comparative Example 2, which has a single particle size of more than 60%, has a higher intensity of the DSC main peak compared to Examples 1 and 2, Comparative Example 1, and Comparative Example 3, indicating lower high-temperature stability.

[0206] In addition, through the results of Tables 3 and 4 above, D 50It can be confirmed that a cell using the cathode material powder of Example 1, which has a particle size of 4 μm or more and satisfies the degree of single particle size of Equation (1), has low gas generation and excellent high-temperature stability.

[0207] As described above, the cathode material powder according to one embodiment of the present invention reduces gas generated in the battery and simultaneously improves thermal stability by controlling the single crystallization of High-Ni single crystals. To this end, according to one embodiment of the present invention, D of a precursor excluding lithium 50 The value is adjusted to approximately 5.5 μm to 9.0 μm, and the specific surface area value of the precursor is 1 m² 2 / g to 4 m 2 D of the cathode material powder manufactured by controlling within the / g range and undergoing primary and secondary calcination and milling processes under the above conditions 50 The value is controlled to be 4 μm or larger and the degree of single particle size is controlled to be about 35% to 60%. It can be confirmed that a lithium secondary battery manufactured using the cathode material powder produced in this way has low gas generation and excellent high-temperature stability.

[0208]

[0209] From the foregoing description, those skilled in the art to which the present invention pertains will understand that the present invention may be implemented in other specific forms without altering its technical concept or essential features. In this regard, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of the present invention should be interpreted as including all modifications or variations derived from the meaning and scope of the claims set forth below and their equivalents, rather than from the detailed description above.

[0210]

[0211] [Explanation of the symbol]

[0212] 10: Anode

[0213] 12: Positive current collector

[0214] 14: Positive active material layer

[0215] 20: Cathode

[0216] 30: Separator

[0217] 40: Electrolytes

[0218] 50: Battery case

[0219] 100: Lithium secondary battery

Claims

1. A lithium nickel-based oxide having a nickel content of 80 mol% or more among metals excluding lithium, and D 50 This is 4 µm or more, and A cathode material powder having a single particle size of 35% to 60% as represented by the following formula (1). Equation (1) In the above equation (1), A is (unit: μm 2 ) is the median of the primary particle area of ​​the above-mentioned cathode material powder measured through SEM image analysis, and D 50 (Unit: μm) is the cumulative average volume of the above-mentioned cathode material powder measured through a particle size analyzer.

2. In Paragraph 1, The above-mentioned cathode material powder comprises a single particle consisting of one primary particle or a pseudo-single particle which is an aggregate of 50 or fewer primary particles.

3. In Paragraph 1, The above lithium nickel-based oxide is a cathode material powder having the composition of [Chemical Formula 1] below. [Chemical Formula 1] Li 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, and M 2 ... comprises one or more selected from Zr, W, Ti, Mg, Ba, Ca, Ta, Nb, and Mo, and 0.8≤x≤1.2, 0.7≤a<1.0, 0 <b<0.3, 0<c<0.3, 0≤d<0.1이다.

4. In Paragraph 1, of the above equation (1) A cathode material powder having a length of 1 μm to 4 μm.

5. In Paragraph 1, A cathode material powder having a tap density of 1.80 g / cc or more.

6. In Paragraph 1, The above-mentioned cathode material powder is a cathode material powder having a rolled density of 3.50 g / cc or more measured after being pressed to 9 ton.

7. In Paragraph 1, A cathode powder further comprising a coating layer on the surface of the lithium nickel-based oxide containing one or more coating elements selected from Al, Ti, W, B, F, P, Mg, Ni, Co, Fe, Cr, V, Cu, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Bi, Si, and S.

8. In Paragraph 1, D of the above cathode material powder 50 Anode powder having a thickness of 4 μm to 7 μm.

9. An anode comprising an anode material powder according to claim 1.

10. A lithium secondary battery comprising a positive electrode according to claim 9.

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