Positive electrode active material for lithium-ion battery, positive electrode for lithium-ion battery, lithium-ion battery, precursor of positive electrode active material for lithium-ion battery, method for producing precursor of positive electrode active material for lithium-ion battery, and method for producing positive electrode active material for lithium-ion battery

Abstract

Provided is a positive electrode active material for a lithium-ion battery, in which the positive electrode active material has a composition represented by the compositional formula: LiaNi(1-b-c-d)CobMncMdO2 (in the formula, M is Mg, Al, and Ca, 0.98≤a≤1.09, 0.06≤b≤0.21, 0.02≤c≤0.32, and 0.0001≤d≤0.01). The 50% cumulative volume particle size D50 is 3.0-11.0 μm, the tap density is 2.0-2.7 g / cc, and the mol% ratio of Mg / (Al+Ca) is 18 or less.

Description

Positive electrode active material for lithium-ion batteries, positive electrode for lithium-ion batteries, lithium-ion battery, precursor of positive electrode active material for lithium-ion batteries, method for producing the precursor of positive electrode active material for lithium-ion batteries, and method for producing positive electrode active material for lithium-ion batteries

[0001] The present invention relates to a positive electrode active material for lithium-ion batteries, a positive electrode for lithium-ion batteries, a lithium-ion battery, a precursor for a positive electrode active material for lithium-ion batteries, a method for producing a precursor for a positive electrode active material for lithium-ion batteries, and a method for producing a positive electrode active material for lithium-ion batteries.

[0002] In recent years, with the rapid expansion of small electronic devices such as mobile phones and laptop computers, the demand for non-aqueous electrolyte secondary batteries as rechargeable power sources has grown rapidly. As positive electrode active materials for non-aqueous electrolyte secondary batteries, lithium cobalt composite oxides, represented by lithium cobalt oxide (LiCoO2), lithium nickel composite oxides, represented by lithium nickel oxide (LiNiO2), and lithium manganese composite oxides, represented by lithium manganese oxide (LiMn2O4), are widely used.

[0003] However, nickel and cobalt are relatively expensive metals, and cobalt in particular is known to have unstable supply and demand due to its limited production countries. For this reason, in recent years, as disclosed in Patent Document 1, methods have been attempted to recover metallic components such as lithium, nickel, and cobalt from waste electrodes and waste batteries in high purity and recycle them into positive electrode active materials.

[0004] Special Publication No. 2022-532575 Publication No. 11-354118

[0005] While the demand for positive electrode active materials in lithium-ion secondary batteries is increasing, a problem arises in that the cycle performance and storage life of superior positive electrode active materials vary depending on the purity of the synthesis raw materials and the purification conditions. Therefore, as disclosed in Patent Document 2, it is necessary to control the purity of the positive electrode active material.

[0006] Waste electrodes and batteries contain various metals in their casings and flame retardants to prevent ignition. Recovering high-purity nickel, cobalt, and lithium requires significant refining costs, resulting in high production costs for positive electrode active materials. In particular, magnesium (Mg), aluminum (Al), and calcium (Ca) are difficult to purify and extract, and considerable recycling costs are incurred to completely remove them.

[0007] Thus, from the perspective of improving battery characteristics by controlling the purity of the positive electrode active material, it is desirable to eliminate impurities such as Mg, Al, and Ca. On the other hand, when recovering high-purity nickel, cobalt, and lithium for recycling waste electrodes and waste batteries, the cost of removing Mg, Al, and Ca is a problem.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a positive electrode active material for lithium-ion batteries that contains Mg, Al, and Ca and exhibits good battery characteristics, a positive electrode for lithium-ion batteries, a lithium-ion battery, a precursor for a positive electrode active material for lithium-ion batteries, a method for producing a precursor for a positive electrode active material for lithium-ion batteries, and a method for producing a positive electrode active material for lithium-ion batteries.

[0009] Based on the above findings, the present invention is defined as follows: 1. Composition formula: Li a Ni (1-b-c-d) Co b Mn c M d A positive electrode active material for lithium-ion batteries, represented by O2 (wherein the above formula, M is Mg, Al, and Ca, and 0.98 ≤ a ≤ 1.09, 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.0001 ≤ d ≤ 0.01), having a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 2.0 to 2.7 g / cc, and a mol% ratio of Mg / (Al + Ca) of 18 or less. 2. A positive electrode active material for lithium-ion batteries, having a BET specific surface area of ​​0.20 to 0.80 m². 2 / g, the positive electrode active material for a lithium ion battery according to 1 above. 3. A positive electrode for a lithium ion battery, comprising the positive electrode active material for a lithium ion battery according to 1 or 2 above. 4. A lithium ion battery, comprising the positive electrode and the negative electrode according to 3 above. 5. Composition formula: Ni (1-b-c-d) Co b Mn c M d (OH)2 (in the above formula, M is Mg, Al and Ca, 0.06≦b≦0.21, 0.02≦c≦0.32, 0.00005≦d≦0.01.) represented by, wherein the 50% cumulative volume particle size D50 is 3.0 to 11.0 µm, the tap density is 1.8 to 2.5 g / cc, and the BET specific surface area is 4.0 to 12.0 m 2 / g, wherein the mol% ratio of Mg / (Al+Ca) is 40 or less, which is a precursor of a positive electrode active material for a lithium ion battery. 6. An aqueous solution containing (a) a nickel salt, (b) a cobalt salt, (c) a manganese salt and (d) a magnesium salt, an aluminum salt and a calcium salt, and (e) a basic aqueous solution containing ammonia and / or a basic aqueous solution of an alkali metal is used as a reaction solution, and a crystallization reaction is carried out while controlling the pH in the reaction solution to 10.0 to 11.5, the ammonium ion concentration to 7 to 20 g / L, and the solution temperature to 59 to 61°C, wherein the composition formula: Ni (1-b-c-d) Co b Mn c M d (OH)2 (in the above formula, M is Mg, Al and Ca, 0.06≦b≦0.21, 0.02≦c≦0.32, 0.00005≦d≦0.01.) represented by, wherein the 50% cumulative volume particle size D50 is 3.0 to 11.0 µm, the tap density is 1.8 to 2.5 g / cc, and the BET specific surface area is 4.0 to 12.0 m 2 / g, wherein the mol% ratio of Mg / (Al+Ca) is 40 or less, which is a method for producing a precursor of a positive electrode active material for a lithium ion battery. 7. The precursor produced by the method for producing a precursor of a positive electrode active material for a lithium ion battery according to 6 above, and a lithium source, wherein the sum of the number of atoms of metals consisting of Ni, Co and Mn (Me n ) and the number of atoms of lithium (Li n ) ratio (Li n / Men A method for producing a positive electrode active material for a lithium-ion battery, comprising the steps of: mixing such that the ratio of ) is 0.98 to 1.09 to form a lithium mixture; and firing the lithium mixture in air or an oxygen atmosphere at 450 to 750°C for 2 to 15 hours, and then firing it further at 700 to 900°C for 2 to 15 hours.

[0010] According to the present invention, it is possible to provide a positive electrode active material for lithium-ion batteries that contains Mg, Al, and Ca and exhibits good battery characteristics, a positive electrode for lithium-ion batteries, a lithium-ion battery, a precursor for the positive electrode active material for lithium-ion batteries, a method for producing the precursor for the positive electrode active material for lithium-ion batteries, and a method for producing the positive electrode active material for lithium-ion batteries.

[0011] Next, embodiments for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and it should be understood that appropriate design changes, improvements, etc., can be made based on the ordinary knowledge of those skilled in the art, without departing from the spirit of the invention.

[0012] (Positive electrode active material for lithium-ion batteries) The positive electrode active material for lithium-ion batteries according to an embodiment of the present invention has the composition formula: Li a Ni (1-b-c-d) Co b Mn c M d It is represented as O2 (where M is Mg, Al, and Ca, and 0.98 ≤ a ≤ 1.09, 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.0001 ≤ d ≤ 0.01). In the composition formula of the positive electrode active material, a, which represents the lithium composition, is controlled to 0.98 ≤ a ≤ 1.09. Since a, which represents the lithium composition, is 0.98 or higher, the reduction of nickel due to lithium deficiency can be suppressed. Also, since a, which represents the lithium composition, is 1.09 or lower, residual alkaline components such as lithium carbonate and lithium hydroxide present on the surface of the positive electrode active material particles, which can become a resistive component when used as a battery, can be suppressed.

[0013] In the embodiment of the present invention, the positive electrode active material for lithium-ion batteries has a nickel composition controlled to 1-b-c-d (0.460 ≤ 1-b-c-d ≤ 0.9199) in its composition formula. Since the nickel composition is 0.460 or higher, a good battery capacity can be obtained for lithium-ion batteries. Furthermore, since the nickel composition is 0.9199 or lower, the crystal structure is stable, and the expansion and contraction behavior of the crystal lattice due to lithium insertion and deinsertion during charging and discharging can be reduced, thereby improving cycle characteristics.

[0014] In the embodiment of the present invention, the positive electrode active material for a lithium-ion battery has a composition formula where the sum of b (representing the cobalt composition), c (representing the manganese composition), and d (representing the magnesium, aluminum, and calcium compositions) is 0.0801 ≤ b + c + d ≤ 0.54. This improves cycle characteristics and reduces the expansion and contraction behavior of the crystal lattice due to lithium insertion and deinsertion during charging and discharging. If the value of b + c + d exceeds 0.54, there is a risk that the amount of cobalt, manganese, magnesium, aluminum, and calcium added is too high, leading to a significant decrease in initial discharge capacity.

[0015] In the positive electrode active material for lithium-ion batteries according to the embodiment of the present invention, the d value, which represents the total composition of Mg, Al, and Ca, is controlled to 0.0001 ≤ d ≤ 0.01. Since d, which represents the Mg, Al, and Ca composition, is 0.0001 or higher, cycle characteristics are improved, and the expansion and contraction behavior of the crystal lattice due to lithium insertion and deinsertion during charging and discharging can be reduced. If d, which represents the Mg, Al, and Ca composition, exceeds 0.01, the amount of Mg, Al, and Ca added is too high, resulting in a large decrease in initial discharge capacity. Thus, the positive electrode active material for lithium-ion batteries according to the embodiment of the present invention contains Mg, Al, and Ca, yet the lithium-ion battery using it exhibits good battery characteristics. Therefore, when recovering high-purity nickel, cobalt, and lithium as recycled waste electrodes and waste batteries, it is possible to manufacture lithium-ion batteries with good battery characteristics using this positive electrode active material while suppressing the cost of removing Mg, Al, and Ca.

[0016] In the embodiment of the present invention, the positive electrode active material for lithium-ion batteries has a Mg / (Al+Ca) mol% ratio of 18 or less. Mg coordinates to the transition metal layer in the layered crystal structure and strongly binds with oxygen, thereby broadening the diffusion pathway for Li ions, making the movement of Li ions smoother during charging and discharging, and contributing to an improvement in battery capacity. However, if the amount of Mg added is too large, Mg will also coordinate to the Li layer, conversely inhibiting the movement of Li ions and reducing battery capacity. Al and Ca can stabilize the crystal structure by partially substituting into the transition metal layer. Even with a large amount of Mg added, by adding Al and Ca so that the Mg / (Al+Ca) mol% ratio is 18 or less, the crystal structure is stabilized, making the movement of Li ions smoother, resulting in excellent discharge capacity, and a lithium-ion battery with good battery characteristics can be manufactured using this positive electrode active material for lithium-ion batteries. In the positive electrode active material for lithium-ion batteries according to the embodiment of the present invention, the Mg / (Al+Ca) mol% ratio is preferably 16 or less, and more preferably 13 or less. Furthermore, in the positive electrode active material for lithium-ion batteries according to the embodiment of the present invention, from the viewpoint of further promoting the movement of Li ions and improving battery capacity, the Mg / (Al+Ca) mol% ratio is preferably 0.01 or more.

[0017] The positive electrode active material for lithium-ion batteries according to the embodiment of the present invention has a form in which a large number of primary particles are aggregated into secondary particles, and may also contain a portion of primary particles that are not aggregated as secondary particles. The shape of the primary particles constituting the secondary particles and the shape of the primary particles existing individually are not particularly limited and may be various shapes such as substantially spherical, substantially elliptical, substantially plate-shaped, or substantially needle-shaped. Furthermore, the form in which a large number of primary particles are aggregated is not particularly limited and may be various forms such as a form in which they aggregate in random directions, or a form in which they aggregate radially from the center almost uniformly to form substantially spherical or substantially elliptical secondary particles.

[0018] The positive electrode active material for lithium-ion batteries according to the embodiment of the present invention has a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm. Here, the 50% cumulative volume particle size D50 is the volume particle size at 50% accumulation in the volume-based cumulative particle size distribution curve. If the 50% cumulative volume particle size D50 of the positive electrode active material for lithium-ion batteries is less than 3.0 μm, the tap density decreases, and the energy density per unit volume decreases. If the 50% cumulative volume particle size D50 of the positive electrode active material for lithium-ion batteries is greater than 11.0 μm, the amount of coarse particles increases, and the coatability deteriorates when coating the slurryed positive electrode active material onto the current collector. Preferably, the 50% cumulative volume particle size D50 of the positive electrode active material for lithium-ion batteries is 7.0 to 10.0 μm. The above method for measuring the 50% cumulative volume particle size D50 involves first dispersing a 100 mg sample (powder) of the positive electrode active material by irradiating it with 40 W of ultrasound for 60 seconds at a 50% flow rate using a Microtrac MT3300EXII laser diffraction particle size distribution analyzer, and then measuring the particle size distribution to obtain a volume-based cumulative particle size distribution curve. Next, the volume particle size at 50% accumulation in the obtained cumulative particle size distribution curve can be used as the 50% cumulative volume particle size D50 of the positive electrode active material powder. The water-soluble solvent used for measurement is filtered through a 0.02 μm filter, with a solvent refractive index of 1.333, particle permeability conditions of transmission, particle refractive index of 1.81, and shape of non-spherical particle. The measurement range is 0.021 to 2000 μm, and the measurement time is 30 seconds.

[0019] The positive electrode active material for a lithium-ion battery according to the embodiment of the present invention has a tap density of 2.0 to 2.7 g / cc. When the tap density of the positive electrode active material is 2.0 g / cc or higher, a battery with a high energy density per unit volume can be constructed. The tap density of the positive electrode active material is preferably 2.1 to 2.7 g / cc, and more preferably 2.3 to 2.7 g / cc. The tap density of the positive electrode active material can be determined, for example, by putting 5 g of positive electrode active material (powder) into a 10 cc graduated cylinder, placing it in a powder density meter "KYT-4000K" manufactured by Seishin Corporation, and performing 1500 taps with a stroke length of 55 mm, then reading the scale on the graduated cylinder. Next, the "sample input amount (5 g) / graduated cylinder scale reading (cc)" is calculated and taken as the tap density (g / cc).

[0020] The positive electrode active material for lithium-ion batteries according to an embodiment of the present invention has a BET specific surface area of 0.20 to 0.80 m 2 / g, which is preferable. When the BET specific surface area is 0.20 m 2 / g or more, the contact area of the positive electrode active material increases, and the conductivity of Li ions becomes favorable. This enables the production of high-capacity lithium-ion batteries. In addition, when the BET specific surface area is 0.80 m 2 / g or more, the precipitation reaction of lithium ions from residual alkali in the positive electrode active material is promoted during repeated charge and discharge cycles. The precipitated lithium compound becomes internal resistance of the battery and reduces the charge-discharge capacity. The BET specific surface area is more preferably 0.30 to 0.70 m 2 / g. The BET specific surface area can be measured by the following method. Specifically, first, 1.0 g of the positive electrode active material (powder) is weighed into a glass cell, set in a degassing apparatus, and the inside of the glass cell is filled with nitrogen gas. Then, heat treatment is performed at 40°C for 20 minutes in a nitrogen gas atmosphere to perform degassing. Thereafter, the glass cell containing the degassed sample (powder) is set in a specific surface area measuring apparatus "Monosorb Model MS-21" manufactured by Quantachrome, and the specific surface area X is measured by the BET method (single-point method) while flowing a mixed gas of He: 70 at% - N₂: 30 at% as the adsorption gas.

[0021] (Precursor of positive electrode active material for lithium-ion battery) The precursor of the positive electrode active material for lithium-ion batteries according to an embodiment of the present invention has a composition formula: Ni (1-b-c-d) Co b Mn c M d (OH)₂ (in the formula, M is Mg, Al and Ca, 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, 0.00005 ≤ d ≤ 0.01), has a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 1.8 to 2.5 g / cc, and a BET specific surface area of 4.0 to 12.0 m 2The ratio is / g, and the mol% ratio of Mg / (Al+Ca) is 40 or less. With this configuration, a positive electrode active material for a lithium-ion battery according to an embodiment of the present invention can be successfully produced using the precursor, having a predetermined composition, a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 2.0 to 2.7 g / cc, and a mol% ratio of Mg / (Al+Ca) of 18 or less.

[0022] (Method for producing a precursor of a positive electrode active material for lithium-ion batteries) Next, a method for producing a precursor of a positive electrode active material for lithium-ion batteries according to an embodiment of the present invention will be described in detail. The precursor of a positive electrode active material for lithium-ion batteries according to an embodiment of the present invention has the composition formula: Ni (1-b-c-d) Co b Mn c M d It is represented by (OH)2 (where M is Mg, Al, and Ca, and 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.00005 ≤ d ≤ 0.01), has a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 1.8 to 2.5 g / cc, and a BET specific surface area of ​​4.0 to 12.0 m². 2The ratio is / g, and the mol% ratio of Mg / (Al+Ca) is 40 or less. The method for producing a precursor of a positive electrode active material for a lithium-ion battery according to an embodiment of the present invention is to first prepare an aqueous solution containing (a) a nickel salt, (b) a cobalt salt, (c) a manganese salt, and (d) a magnesium salt, an aluminum salt, and a calcium salt, and (e) a basic aqueous solution containing ammonia and / or a basic aqueous solution of an alkali metal. Examples of (a) nickel salts include nickel sulfate, nickel nitrate, or nickel hydrochloride. Examples of (b) cobalt salts include cobalt sulfate, cobalt nitrate, or cobalt hydrochloride. Examples of (c) manganese salts include manganese sulfate, manganese nitrate, or manganese hydrochloride. Examples of (d) magnesium salts include magnesium sulfate, magnesium nitrate, or magnesium hydrochloride. Examples of aluminum salts include aluminum sulfate, sodium aluminate, aluminum nitrate, or aluminum chloride. Examples of calcium salts include calcium sulfate, calcium nitrate, or calcium chloride. Furthermore, the magnesium salt, aluminum salt, and calcium salt may be added as raw materials or may be present as impurities. (e) Examples of basic aqueous solutions containing ammonia include aqueous ammonia solution, aqueous ammonium sulfate solution, aqueous ammonium carbonate solution, aqueous ammonium hydrochloride solution, etc. Examples of basic aqueous solutions of alkali metals include aqueous solutions of sodium hydroxide, potassium hydroxide, carbonate, etc. Examples of aqueous solutions of carbonates include aqueous solutions using salts of carbonate groups, such as aqueous sodium carbonate solution, aqueous potassium carbonate solution, aqueous sodium bicarbonate solution, and aqueous potassium bicarbonate solution.

[0023] Further, the composition of the aqueous solution can be appropriately adjusted according to the composition of the precursor to be produced, and it is preferably any of the following: (a) an aqueous solution containing 30 to 150 g / L of nickel ions, (b) an aqueous solution containing 3 to 25 g / L of cobalt ions, (c) an aqueous solution containing 1 to 32 g / L of manganese ions, (d) an aqueous solution containing 0.003 to 0.06 g / L of magnesium ions, aluminum ions and calcium ions, (e) a basic aqueous solution containing 7 to 28 mass% of ammonia and / or a basic aqueous solution having an alkali metal concentration of 10 to 30 mass%.

[0024] Next, an aqueous solution containing (a) a nickel salt, (b) a cobalt salt, (c) a manganese salt, (d) a magnesium salt, an aluminum salt, and a calcium salt as described above, and (e) a basic aqueous solution containing ammonia and / or a basic aqueous solution of an alkali metal is used as a reaction solution, and a crystallization reaction is performed while controlling the pH in the reaction solution to 10.0 to 11.5, the ammonium ion concentration to 7 to 20 g / L, and the solution temperature to 59 to 61°C. At this time, the chemical solutions may be respectively fed to the reaction tank from three tanks: a tank holding the mixed aqueous solution of the nickel salt, cobalt salt, manganese salt, magnesium salt, aluminum salt and calcium salt, a tank holding the basic aqueous solution containing ammonia, and a tank holding the basic aqueous solution of an alkali metal. By performing the crystallization reaction while controlling the pH in the reaction solution during the coprecipitation reaction to 10.0 to 11.5, the ammonium ion concentration to 7 to 20 g / L, and the solution temperature to 59 to 61°C, the solubility of metals in the reaction solution can be controlled, particles in which magnesium, aluminum and calcium are uniformly dispersed can be produced, and the precursor of the positive electrode active material according to the embodiment of the present invention having good discharge characteristics can be produced. In addition, by optimizing the reaction conditions for the metal hydroxide that is the precursor as described above, adhesion of impurities to the surface of the positive electrode active material obtained after firing is satisfactorily suppressed, so washing is not required. Furthermore, a chelating agent and a metal oxide coating during the coprecipitation reaction are not required. As a result, production efficiency is improved.

[0025] (Method for manufacturing positive electrode active material for lithium-ion batteries) Next, a method for manufacturing a positive electrode active material for lithium-ion batteries according to an embodiment of the present invention will be described in detail. The method for manufacturing a positive electrode active material for lithium-ion batteries according to an embodiment of the present invention first involves adding a lithium source to the precursor of the positive electrode active material for lithium-ion batteries according to an embodiment of the present invention, which has been prepared as described above, and the sum of the number of atoms of metals consisting of Ni, Co and Mn (Me n ) and the number of lithium atoms (Li n ) ratio (Li n / Me n The mixture is formed by mixing the materials so that the ratio is 0.98 to 1.09. Examples of lithium sources include lithium carbonate or lithium hydroxide. As for the mixing method, it is preferable to adjust the mixing ratio of each raw material and dry mix them using a Henschel mixer, automatic mortar and pestle, or V-type mixer.

[0026] Next, the lithium mixture is calcined in air or an oxygen atmosphere at 450-750°C for 2-15 hours, and then further calcined at 700-900°C for 2-15 hours. After that, if necessary, the calcined body can be crushed using, for example, a pulverizer to obtain the positive electrode active material powder.

[0027] (Positive electrode for lithium-ion battery and lithium-ion battery) The positive electrode for a lithium-ion battery according to an embodiment of the present invention has a structure in which a positive electrode mixture prepared by mixing the positive electrode active material for lithium-ion batteries having the above-described configuration, a conductive additive, and a binder is provided on one or both sides of a current collector. Furthermore, the lithium-ion battery according to an embodiment of the present invention comprises a positive electrode for lithium-ion batteries having such a configuration and a known negative electrode for lithium-ion batteries.

[0028] Examples of conductive additives include metallic conductive additives (aluminum, stainless steel (SUS), silver, gold, copper, and titanium, etc.), carbon-based conductive additives (graphite and carbon black (acetylene black, Ketjen black, furnace black, channel black, and thermal lamp black, etc.)), and mixtures thereof. These conductive additives may be used individually or in combination of two or more. They may also be used as alloys or metal oxides. In particular, from the viewpoint of electrical stability, aluminum, stainless steel, silver, gold, copper, titanium, carbon-based conductive additives, and mixtures thereof are more preferred, even more preferably aluminum, stainless steel, silver, gold, and carbon-based conductive additives, and especially preferably carbon-based conductive additives. These conductive additives may also be formed by coating a particulate ceramic material or resin material with a conductive material (preferably a metallic conductive additive from the above-mentioned conductive additives) by plating or the like. The shape (form) of the conductive additive is not limited to particle form, but may be in a form other than particle form, and may be in a form that has been put into practical use as so-called filler-type conductive additives, such as carbon nanofibers and carbon nanotubes.

[0029] Examples of binders include substances commonly used in positive electrode mixtures for lithium-ion batteries, but it is preferable that they be copolymers having a structure derived from vinylidene fluoride, polyvinylidene fluoride (PVDF), copolymers or homopolymers having a structure derived from tetrafluoroethylene (TEF), or copolymers or homopolymers having a structure derived from hexafluoropropylene (HFP). Specifically, examples include PVDF-HFP, PVDF-HFP-TEF, PVDF-TEF, TEF-HFP, etc.

[0030] The positive electrode mixture is prepared by mixing a positive electrode active material for lithium-ion batteries, a conductive additive, and a binder in a solvent to form a positive electrode mixture slurry. This slurry is then applied to one or both sides of a current collector, and after drying and other processes, it is placed on the current collector to form a positive electrode active material layer.

[0031] As the solvent for the positive electrode mixture slurry, known organic solvents, such as hydrocarbon organic solvents, amide compounds, lactam compounds, urea compounds, organosulfur compounds, and cyclic organophosphorus compounds, can be used as single solvents or as mixed solvents. As hydrocarbon organic solvents, saturated hydrocarbons, unsaturated hydrocarbons, or aromatic hydrocarbons can be used. Examples of saturated hydrocarbons include hexane, pentane, 2-ethylhexane, heptane, decane, and cyclohexane. Examples of unsaturated hydrocarbons include hexene, heptene, and cyclohexene. Examples of aromatic hydrocarbons include toluene, xylene, decalin, and 1,2,3,4-tetrahydronaphthalene. Of these, toluene and xylene are particularly preferred.

[0032] Materials that constitute the current collector include metallic materials such as copper, aluminum, titanium, stainless steel, nickel and alloys thereof, as well as calcined carbon, conductive polymer materials, and conductive glass. Among these, aluminum is more preferred from the viewpoint of weight reduction, corrosion resistance, and high conductivity. Furthermore, the current collector is preferably a resin current collector made of a conductive polymer material. The shape of the current collector is not particularly limited and may be a sheet-shaped current collector made of the above material, or a deposited layer made of fine particles composed of the above material. The thickness of the current collector is not particularly limited, but is preferably 1 to 30 μm. As the conductive polymer material that constitutes the resin current collector, for example, a conductive polymer or a resin to which a conductive agent is added as needed can be used.

[0033] From the viewpoint of battery performance, the thickness of the positive electrode for lithium-ion batteries is preferably 10 to 100 μm, and more preferably 20 to 50 μm.

[0034] A lithium-ion battery using a lithium-ion battery positive electrode is obtained by combining it with a negative electrode (the opposite electrode), housing it in a cell container with a separator, injecting electrolyte, and sealing the cell container. Alternatively, a bipolar electrode can be fabricated by forming a positive electrode on one side of a current collector and a negative electrode on the other side, stacking the bipolar electrode with a separator and housing it in a cell container, injecting electrolyte, and sealing the cell container.

[0035] Examples of negative electrodes include those containing a negative electrode active material, conductive additives, and current collectors. Known negative electrode active materials for lithium-ion batteries can be used as the negative electrode active material, including carbon-based materials (graphite, non-graphitizable carbon, amorphous carbon, resin-fired bodies (e.g., phenolic resin and furan resin fired and carbonized), cokes (e.g., pitch coke, needle coke, and petroleum coke), and carbon fibers), silicon-based materials (silicon, silicon oxide (SiO₂)). x Examples include silicon-carbon composites (carbon particles coated with silicon and / or silicon carbide, silicon particles or silicon oxide particles coated with carbon and / or silicon carbide, and silicon carbide, etc.), silicon alloys (silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon-manganese alloy, silicon-copper alloy, and silicon-tin alloy, etc.), conductive polymers (e.g., polyacetylene and polypyrrole), metals (tin, aluminum, zirconium, and titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxide, etc.), metal alloys (e.g., lithium-tin alloy, lithium-aluminum alloy, and lithium-aluminum-manganese alloy, etc.), and mixtures of these with carbon-based materials. Furthermore, conductive additives similar to those used for the positive electrode can be suitably used.

[0036] Examples of current collectors include those similar to the current collectors constituting the positive electrode described above, and copper is preferred from the viewpoint of weight reduction, corrosion resistance, and high conductivity. Alternatively, a resin current collector may be used, and one similar to the current collector constituting the positive electrode described above can be suitably used. The thickness of the current collector is not particularly limited, but is preferably 10 to 60 μm.

[0037] Examples of separators include known separators for lithium-ion batteries such as porous films made of polyethylene or polypropylene, laminated films of porous polyethylene film and porous polypropylene, nonwoven fabrics made of synthetic fibers (polyester fibers and aramid fibers, etc.) or glass fibers, and those on which ceramic fine particles such as silica, alumina, and titania are attached to the surface.

[0038] The following examples are provided to better understand the present invention and its advantages, but the present invention is not limited to these examples.

[0039] (Example 1) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.6 and the ammonium ion concentration was 10.3 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.05. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 900°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0040] (Example 2) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.4 and the ammonium ion concentration was 11.5 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor for the positive electrode active material is taken as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.09. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 900°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0041] (Example 3) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.3 and the ammonium ion concentration was 8.2 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.07. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0042] (Example 4) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH in the reaction vessel was 10.1 and the ammonium ion concentration was 11.2 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature in the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.05. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 900°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0043] (Example 5) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to obtain a Ni:Co:Mn ratio of 50:20:30 to prepare a 1.5 mol / L mixed metal salt solution. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 11.3 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.06. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0044] (Example 6) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.1 and the ammonium ion concentration was 9.3 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.08. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0045] (Example 7) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 10.5 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is taken as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.05. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0046] (Example 8) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 9.9 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is taken as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.05. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0047] (Example 9) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 11.1 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.08. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0048] (Example 10) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH in the reaction vessel was 10.2 and the ammonium ion concentration was 10.7 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature in the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is taken as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.05. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0049] (Example 11) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 10.7 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is taken as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.05. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0050] (Example 12) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 9.9 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.08. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0051] (Example 13) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 10.0 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.06. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0052] (Example 14) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 10.2 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor of the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.07. The lithium carbonate and the precursor of the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0053] (Example 15) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 50:20:30. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.6 and the ammonium ion concentration was 14.8 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms to Me (Li / Me) was 1.08. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0054] (Example 16) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 82:15:3. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 11.2 and the ammonium ion concentration was 13.5 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.01. The lithium hydroxide and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an oxygen atmosphere at 500°C for 2 hours, then heated to 740°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0055] (Example 17) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 90:7:3. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 11.0 and the ammonium ion concentration was 7.2 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 820 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.01. The lithium hydroxide and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an oxygen atmosphere at 500°C for 2 hours, then heated to 720°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0056] (Example 18) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to prepare a 1.5 mol / L mixed metal salt solution with a ratio of Ni:Co:Mn = 90:7:3. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 11.0 and the ammonium ion concentration was 10.0 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 820 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is defined as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 0.98. The lithium hydroxide and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an oxygen atmosphere at 500°C for 2 hours, then heated to 720°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0057] (Comparative Example 1) First, nickel sulfate, cobalt sulfate, and manganese sulfate were weighed in predetermined amounts to obtain a Ni:Co:Mn ratio of 50:20:30 to prepare a 1.5 mol / L mixed metal salt solution. The Mg, Al, and Ca concentrations of this mixed metal salt solution were as shown in "Me Solution Analysis" of "Me Sulfate Solution" in Table 1. Next, the mixed metal salt solution, ammonia water, and a 20% by mass sodium hydroxide aqueous solution were introduced into a reaction vessel equipped with a stirring blade so that the pH of the reaction vessel was 10.2 and the ammonium ion concentration was 11.1 g / L, and a crystallization reaction was carried out to precipitate a nickel-cobalt-manganese complex hydroxide compound. At this time, the reaction vessel was kept warm with a water jacket so that the rotation speed of the stirring blade was 1000 rpm and the liquid temperature of the reaction vessel was maintained at 60°C. In addition, nitrogen gas was introduced into the reaction vessel to prevent oxidation of the coprecipitate produced in the crystallization reaction. The gas introduced into the reaction vessel can be any gas that does not promote oxidation, such as helium, neon, argon, or carbon dioxide, and is not limited to nitrogen gas as described above. Next, the obtained precipitate was filtered by suction, washed with water, and dried in a box-type dryer at 120°C for 12 hours. This produced a precursor for the positive electrode active material. Next, when the sum of the number of atoms of the metals consisting of Ni, Co, and Mn in the precursor for the positive electrode active material is denoted as Me, the ratio of the number of lithium (Li) atoms (Li / Me) to Me was 1.03. The lithium carbonate and the precursor for the positive electrode active material were mixed and mixed in an automatic mortar for 30 minutes to obtain a mixed powder. Next, the mixed powder was filled into an alumina mortar and calcined in a muffle furnace under an atmospheric atmosphere at 750°C for 2 hours, then heated to 880°C and held at that temperature for 8 hours to obtain the positive electrode active material.

[0058] (Composition) The composition of the precursor and cathode active material powders of Examples 1 to 18 and Comparative Example 1 was measured as follows. For nickel, cobalt, and manganese compositions, a specified amount of each obtained precursor and cathode active material sample (powder) was weighed, decomposed by alkaline fusion, and then analyzed using an inductively coupled plasma atomic emission spectrometer (ICP-OES) "PS7800" manufactured by Hitachi High-Tech Corporation. For aluminum, magnesium, and calcium compositions of the precursor and cathode active material, a specified amount of each obtained precursor and cathode active material sample (powder) was weighed, dissolved by acid decomposition, and then analyzed using an ICP mass spectrometer (ICP-MS) "SPQ9700" manufactured by SII Nanotechnology Corporation.

[0059] (50% Cumulative Volume Particle Size D50) For the precursor and positive electrode active material powders of Examples 1 to 18 and Comparative Example 1, the 50% cumulative volume particle size D50 (also called "average particle size D50") was measured as follows. 100 mg of each obtained precursor and positive electrode active material sample (powder) was dispersed by irradiating with 40 W ultrasonic waves for 60 seconds at a 50% flow rate using a Microtrac MT3300EXII laser diffraction particle size distribution analyzer, and the particle size distribution was measured to obtain a volume-based cumulative particle size distribution curve. In the obtained cumulative particle size distribution curve, the volume particle size at 50% accumulation was defined as the 50% cumulative volume particle size D50 of the positive electrode active material powder. For the measurement, the water-soluble solvent was passed through a 0.02 μm filter, with a solvent refractive index of 1.333, particle permeability conditions set to permeable, particle refractive index of 1.81, and particle shape set to non-spherical. The measurement range was 0.021 to 2000 μm, and the measurement time was 30 seconds.

[0060] (Tap Density) The tap density of the precursor and positive electrode active material powders of Examples 1 to 18 and Comparative Example 1 was measured as follows. 5 g of each obtained precursor and positive electrode active material sample (powder) was placed in a 10 cc graduated cylinder and set up in a powder density meter "KYT-4000K" manufactured by Seishin Corporation. After 1500 taps with a stroke length of 55 mm, the scale of the graduated cylinder was read. Next, the "sample input amount (5 g) / graduated cylinder scale reading (cc)" was calculated and taken as the tap density (g / cc).

[0061] (BET Specific Surface Area) The BET specific surface area of ​​the precursor and cathode active material powders of Examples 1 to 18 and Comparative Example 1 was measured as follows. 1.0 g of each obtained precursor and cathode active material sample (powder) was weighed into a glass cell, set in a degasser, filled with nitrogen gas, and then heat-treated at 40°C for 20 minutes in a nitrogen gas atmosphere to degas it. After that, the glass cell containing the degassed sample (powder) was set in a Quantachrome Monosorb Model MS-21 specific surface area measuring device, and the specific surface area X was measured by the BET method (single-point method) while flowing a mixed gas of He: 70 at% - N2: 30 at% as the adsorption gas.

[0062] (Discharge Capacity) The discharge capacity of the positive electrode active material powders of Examples 1 to 18 and Comparative Example 1 was measured as follows. The obtained positive electrode active material was weighed with a conductive additive (acetylene black) and a binder (polyvinylidene fluoride) in a ratio of 90:5:5. The binder was dissolved in an organic solvent (N-methylpyrrolidone), and the positive electrode material and conductive material were mixed to form a slurry. This slurry was then applied to an Al foil, dried, and pressed to form the positive electrode. Subsequently, a 2032 type coin cell for evaluation was prepared with Li as the counter electrode, and the initial characteristics of the battery at 25°C (charging capacity, discharging capacity, charge / discharge characteristics) were measured using an electrolyte solution of 1M-LiPF6 dissolved in EC-DMC (3:7). The charge / discharge conditions were: charging conditions: CC / CV 4.3V, 0.1C, discharge conditions: CC 0.05C, up to 3.0V. Tables 1 to 3 show the manufacturing conditions and evaluation results for Examples 1 to 18 and Comparative Example 1 described above.

[0063]

[0064]

[0065]

[0066] (Evaluation Results) The positive electrode active materials of Examples 1 to 18 all had the following compositional formula. Note that the "Li / Me ratio" in Tables 2 and 3 indicates the compositional ratio of Li to the total of Ni, Co, and Mn in the positive electrode active material. Compositional formula: Li a Ni (1-b-c-d) Co b Mn c M d O2 (In the formula, M is Mg, Al, and Ca, and 0.98 ≤ a ≤ 1.09, 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.0001 ≤ d ≤ 0.01.) Furthermore, the positive electrode active materials of Examples 1 to 18 all had a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 2.0 to 2.7 g / cc, and a mol% ratio of Mg / (Al + Ca) of 18 or less, and exhibited good battery characteristics (discharge capacity).

[0067] The positive electrode active material in Comparative Example 1 had a mol% ratio of Mg / (Al+Ca) exceeding 18, resulting in poor battery characteristics (discharge capacity).

[0068] According to one embodiment of the present invention, it is possible to provide a positive electrode active material for lithium-ion batteries that contains Mg, Al, and Ca and exhibits good battery characteristics, a positive electrode for lithium-ion batteries, a lithium-ion battery, a precursor for the positive electrode active material for lithium-ion batteries, a method for producing the precursor for the positive electrode active material for lithium-ion batteries, and a method for producing the positive electrode active material for lithium-ion batteries. This could lead to the widespread use of non-fossil energy, reduce the use of fossil energy such as oil and gas which currently account for a large portion of energy production, and potentially contribute to mitigating global warming. Furthermore, since the main materials used are substances with low environmental impact such as lithium, carbon, manganese, nickel, and cobalt, and harmful substances such as cadmium, lead, and mercury are not used, it is possible to reduce the environmental burden. For this reason, one embodiment of the present invention may contribute to Goal 7, "Ensure access to affordable, reliable, sustainable, and modern energy for all," Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," and Goal 12, "Ensure sustainable consumption and production patterns," all of which are led by the United Nations.

Claims

1. Composition formula: Li a Ni (1-b-c-d) Co b Mn c M d A positive electrode active material for lithium-ion batteries, represented by O2 (wherein the above formula, M is Mg, Al, and Ca, and 0.98 ≤ a ≤ 1.09, 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.0001 ≤ d ≤ 0.01), having a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 2.0 to 2.7 g / cc, and a mol% ratio of Mg / (Al + Ca) of 18 or less.

2. BET specific surface area is 0.20 to 0.80 m² 2 The positive electrode active material for a lithium-ion battery according to claim 1, wherein the value is / g.

3. A positive electrode for a lithium-ion battery comprising the positive electrode active material for a lithium-ion battery described in claim 1 or 2.

4. A lithium-ion battery comprising a positive electrode and a negative electrode for a lithium-ion battery as described in claim 3.

5. Composition formula: Ni (1-b-c-d) Co b Mn c M d (OH) 2 (In the above formula, M is Mg, Al and Ca, 0.06≦b≦0.21, 0.02≦c≦0.32, 0.00005≦d≦0.01.) which is represented by the formula, has a 50% cumulative volume particle size D50 of 3.0 to 11.0 µm, a tap density of 1.8 to 2.5 g / cc, and a BET specific surface area of 4.0 to 12.0 m 2 / g, and a Mg / (Al+Ca) molar ratio of 40 or less, which is a precursor for a positive electrode active material for lithium ion batteries.

6. The reaction solution is an aqueous solution containing (a) nickel salt, (b) cobalt salt, (c) manganese salt, and (d) magnesium salt, aluminum salt, and calcium salt, and (e) a basic aqueous solution containing ammonia and / or a basic aqueous solution of an alkali metal. The crystallization reaction is carried out while controlling the pH of the reaction solution to 10.0 to 11.5, the ammonium ion concentration to 7 to 20 g / L, and the liquid temperature to 59 to 61°C. Composition formula: Ni (1-b-c-d) Co b Mn c M d It is represented as (OH)2 (wherein the above formula M is Mg, Al, and Ca, and 0.06 ≤ b ≤ 0.21, 0.02 ≤ c ≤ 0.32, and 0.00005 ≤ d ≤ 0.01), has a 50% cumulative volume particle size D50 of 3.0 to 11.0 μm, a tap density of 1.8 to 2.5 g / cc, and a BET specific surface area of ​​4.0 to 12.0 m². 2 A method for producing a precursor of a positive electrode active material for lithium-ion batteries, wherein the amount is / g and the mol% ratio of Mg / (Al+Ca) is 40 or less.

7. A precursor produced by the method for producing a precursor of a positive electrode active material for a lithium-ion battery according to claim 6, and a lithium source, wherein the sum of the number of atoms of the metals consisting of Ni, Co and Mn (Me n ) and the number of lithium atoms (Li n ) ratio (Li n / Me n A method for producing a positive electrode active material for a lithium-ion battery, comprising the steps of: mixing such that the ratio of ) is 0.98 to 1.09 to form a lithium mixture; and firing the lithium mixture in air or an oxygen atmosphere at 450 to 750°C for 2 to 15 hours, and then firing it further at 700 to 900°C for 2 to 15 hours.

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