Method for producing particulate (oxy) hydroxides or oxides

Abstract

A method for producing a particulate (oxy)hydroxide or carbonate or oxide of TM, the TM comprising nickel and at least one metal selected from cobalt, manganese and aluminium, the method comprising the steps of: (a) providing an aqueous solution containing a water-soluble salt of Ni (α1), and an aqueous solution containing a water-soluble salt of Co (α2) or an aqueous solution containing a water-soluble salt of Mn (α3) or an aqueous solution containing a water-soluble compound of Al (α4), and an aqueous solution containing an alkali metal hydroxide or carbonate (β), and optionally an aqueous solution containing ammonia or an organic acid or an alkali metal salt thereof (γ); (b) combining in a continuous reactor solution (α1), solution (β), at least one of solutions (α2) or (α3) or (α4) and, where applicable, solution (γ), thereby producing solid particles of hydroxide or carbonate of TM, wherein these solutions are introduced into the continuous reactor at different positions; (c) separating the particles from step (b) from the liquid phase by solid-liquid separation. Includes.

Description

[Technical Field]

[0001] The present invention relates to a method for producing particulate (oxy) hydroxide, carbonate, or oxide of TM, wherein TM comprises nickel and at least one metal selected from cobalt, manganese, and aluminum, and the method comprises the following steps: (a) A step of providing an aqueous solution containing a water-soluble salt of Ni (α1), an aqueous solution containing a water-soluble salt of Co (α2) or an aqueous solution containing a water-soluble salt of Mn (α3) or an aqueous solution containing a water-soluble compound of Al (α4), an aqueous solution containing an alkali metal hydroxide or carbonate (β), and optionally an aqueous solution containing ammonia or an organic acid or its alkali metal salt (γ), (b) A step of producing solid particles of TM hydroxide or carbonate by combining solution (α1), solution (β), at least one of solutions (α2), (α3), or (α4), and solution (γ) in a continuous reactor, wherein these solutions are introduced into the continuous reactor at different locations. (c) A step of separating particles from the liquid phase from step (b) by solid-liquid separation method. Includes. [Background technology]

[0002] Currently, lithified transition metal oxides are used as electrode active materials in lithium-ion batteries. Extensive research and development have been conducted over the past few years to improve not only properties such as charge density and specific energy, but also other properties such as reduced cycle life and capacity loss, which can adversely affect the lifespan or applicability of lithium-ion batteries. Further efforts have also been made to improve manufacturing methods.

[0003] In a typical method for producing cathode materials for lithium-ion batteries, a so-called precursor is first formed by coprecipitation of a transition metal as a carbonate, oxide, or preferably as a hydroxide, such as an oxyhydroxide, which may be basic or not. Next, this precursor is mixed with a lithium source, such as LiOH, Li2O, or Li2CO3 (but not limited to these), and calcined at a high temperature. The lithium salt(s) can be used as a hydrate(s) or in a dehydrated form. Calcination or calcination, often called heat treatment or heating of the precursor, is usually carried out at temperatures in the range of 600 to 1000°C. During the heat treatment, a solid-phase reaction occurs to form the electrode active material. The heat treatment is carried out in the heating zone of an oven or kiln.

[0004] A typical class of cathode active materials that provide high energy density is Ni-rich, containing at least 80 mol% Ni relative to the content of non-lithium metals. The properties of the cathode active material ("CAM"), such as capacity and especially cycle life, are strongly influenced by the interaction between the CAM and the electrolyte in each electrochemical cell. Here, Ni in particular is highly reactive and tends to lead to the formation of by-products that reduce the battery capacity during cycling. To overcome this, it has been proposed to coat the CAM with an aluminum or cobalt compound that significantly suppresses unwanted side reactions in the electrochemical cell. Such coating is usually carried out in a separate post-processing step after firing. Such processing steps are expensive and significantly increase the specific manufacturing cost of the CAM.

[0005] In many cases, the properties of the precursor are reflected to some extent in the properties of the respective electrode active materials, such as particle size distribution and the content of each transition metal. Therefore, it is possible to influence the properties of the electrode active materials by manipulating the properties of the precursor. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, an object of the present invention is to provide a method for producing a wide variety of precursors using highly flexible, simple, and versatile equipment. In particular, an object of the present invention is to provide a continuous process for producing precursors exhibiting an elemental gradient or coating in particles, etc., which can be produced using highly flexible, simple, and versatile equipment. A further object of the present invention was to provide an electrode active material precursor that can be easily produced and exhibits a gradient or coating. [Means for solving the problem]

[0007] Therefore, the method defined at the beginning, which will also be referred to below as "the method of the present invention" or "the method according to the present invention," was found. [Brief explanation of the drawing]

[0008] [Figure 1] [Modes for carrying out the invention]

[0009] The present invention relates to a method for producing particulate (oxy) hydroxide, oxide, or carbonate of TM. Therefore, the particulate (oxy) hydroxide, oxide, or carbonate functions as a precursor of the electrode active material and is therefore also called a precursor.

[0010] In one embodiment of the present invention, the resulting precursor is composed of secondary particles, which are aggregates of primary particles.

[0011] In one embodiment of the present invention, the specific surface area (BET) of the obtained precursor is determined by nitrogen adsorption, for example, according to DIN-ISO 9277:2003-05, and is 2 to 70 m 2 The range is / g. The gas release temperature is 120°C.

[0012] The precursor is a (oxy)hydroxide of TM, where TM comprises Ni and at least one selected from Co, Mn, and Al, and optionally at least one further metal selected from Ti, Zr, Mo, W, Mg, and Nb.

[0013] In one embodiment of the present invention, TM has the general formula (I) (Ni a Co b Mn c ) 1-d M d (I) (where a ranges from 0.5 to 0.95, preferably from 0.8 to 0.92, b ranges from 0 or 0.025 to 0.5, preferably from 0.025 to 0.15, c ranges from 0 to 0.2, preferably from 0 to 0.15, d ranges from 0 to 0.1, preferably from 0 to 0.05, M is selected from Mg, Al, Ti, Zr, Mo, W, and Nb, a + b + c = 1, b + c > 0, or M contains Al and d > 0) is a combination of metals according to. [[ID==36]]

[0014] TM may contain trace amounts of further metal ions, such as trace amounts of ubiquitous metals such as sodium, iron, calcium, or zinc, but such traces are not considered in the context of the present invention. By trace amounts in this context is meant amounts of 0.05 mol% or less relative to the total metal content of TM.

[0015] The precursor is a particulate material. In one embodiment of the present invention, the precursor has an average particle size D50 in the range of 3 to 20 μm, preferably 4 to 16 μm. The average particle size can be determined, for example, by light scattering or laser diffraction or electroacoustic spectroscopy. The particles are composed of primary particles, in particular aggregates of primary particles, and the above particle size refers to the particle size of the secondary particles.

[0016] In one embodiment of the present invention, the span of the particle size distribution of the precursor is in the range of 0.9 to 2.0. This span is defined as [(D90)-(D10)] / (D50), and the values of (D90), (D50), and (D10) are determined by dynamic light scattering.

[0017] The particulate material may have an irregular shape, but in a preferred embodiment, the particulate material has a regular shape, such as an elliptical shape or even a spherical shape. The aspect ratio may be in the range of 1 to 10, preferably 1 to 3, and even more preferably 1 to 1.5. The aspect ratio is defined as the ratio of the width to the length, specifically the ratio of the particle size of the longest dimension to the particle size of the shortest dimension. A perfect spherical particle has an aspect ratio of 1.

[0018] The method of the present invention includes three steps, which are also referred to as step (a), step (b), and step (c) respectively below, and may further include additional (optional) steps. Steps (a) to (c) will be described in more detail below.

[0019] Step (a) includes providing an aqueous solution (α1) containing a water-soluble salt of Ni, and an aqueous solution (α2) containing a water-soluble salt of Co or an aqueous solution (α3) containing a water-soluble salt of Mn or an aqueous solution (α3) containing a water-soluble compound of Al, and an aqueous solution (β) containing a hydroxide or carbonate of an alkali metal, and optionally an aqueous solution (γ) containing ammonia or an organic acid or an alkali metal salt thereof. The aqueous solution is simply referred to as a solution.

[0020] The term water-soluble salts of cobalt and nickel, or manganese, or metals other than nickel, cobalt, and manganese refers to salts showing a solubility in distilled water at 25°C of 25 g / l or more, and the amount of the salt is determined with omission of water resulting from crystal water and aquo complexes. The water-soluble salts of nickel, cobalt, and manganese are preferably Ni 2+ and Co 2+ and Mn 2+These can be water-soluble salts of each. Examples of water-soluble salts of nickel and cobalt include sulfates, nitrates, acetates, and halides, particularly chlorides. Nitrates and sulfates are preferred, with sulfates being more preferred.

[0021] Therefore, the term "water-soluble aluminum compounds" refers to compounds such as Al2(SO4)3, Al(NO3)3, KAl(SO4)2, NaAlO2, and NaAl(OH)4. Depending on the selection of the water-soluble aluminum compound, the pH value of the aqueous solution (α4) may be in the range of 1 to 3 or greater than 13.

[0022] Solution (α1) may have a pH value in the range of 2 to 5. In embodiments where a higher pH value is desired, ammonia may be added to solution (α1). However, preferably, ammonia is not added to solution (α1). Solutions (α2) and (α3) may also have a pH value in the range of 2 to 5.

[0023] In one embodiment of the present invention, the concentrations of nickel in solution (α1), cobalt in solution (α2), manganese in solution (α3), and aluminum in solution (α4) can be selected within a wide range, depending on the circumstances. Preferably, the concentration of each metal is selected to be within the range of 1 to 1.8 moles of metal per 1 kg of solution, more preferably 1.5 to 1.7 moles of metal per 1 kg of solution.

[0024] Step (a) further provides an aqueous solution of an alkali metal hydroxide or carbonate, which is also referred to below as solution (β). Examples of alkali metal hydroxides include lithium hydroxide, preferably potassium hydroxide, and a combination of sodium hydroxide and potassium hydroxide, and more preferably sodium hydroxide. Examples of alkali metal carbonates include sodium carbonate and potassium carbonate, with sodium carbonate being preferred.

[0025] In one embodiment of the present invention, solution (β) mainly contains alkali metal hydroxides and contains carbonates in a certain amount, for example, 0.1 to 2% by mass relative to the amount of each alkali metal hydroxide, which are added intentionally or by aging of the solution or each alkali metal hydroxide.

[0026] Solution (β) may have a hydroxide concentration in the range of 0.1 to 12 mol / l, preferably 6 to 10 mol / l.

[0027] The pH value of solution (β) is preferably 11.5 or higher, and in this embodiment having an alkali metal hydroxide, the pH value is preferably 13 or higher, for example, 14.5.

[0028] In the method of the present invention, ammonia is used, but it is preferable to supply it separately as solution (γ) or as solution (β), and not as solution (α).

[0029] In step (a), optionally, an aqueous solution (γ) containing ammonia or a carboxylic acid, preferably a low-volatility carboxylic acid, may be provided. In this context, low volatility means a boiling point or decomposition temperature at atmospheric pressure that exceeds 200°C. Examples include amino acids, e.g., glycine; dicarboxylic acids, e.g., tartaric acid; and tricarboxylic acids, e.g., citric acid; or their respective alkali metal salts. The concentration may be in the range of 1 to 150 g of each carboxylic acid, calculated excluding the alkali metal counterion. In embodiments in which solution (γ) contains ammonia, the concentration of ammonia may be in the range of 10 to 250 g / l.

[0030] Step (a) may provide an aqueous solution (δ) containing at least one water-soluble compound of metal M selected from any two, Mg, Ti, Zr, Mo, W, and Nb.

[0031] Examples of suitable Mg compounds include MgSO4, Mg(NO3)2, magnesium acetate, and MgCl2, with MgSO4 being preferred.

[0032] Examples of suitable Ti compounds include Ti(SO4)2, TiOSO4, TiO(NO3)2, and Ti(NO3)4, with Ti(SO4)2 being preferred.

[0033] Examples of suitable Zr compounds include zirconium acetate, Zr(SO4)2, ZrOSO4, ZrO(NO3)2, and Zr(NO3)4, with Zr(SO4)2 being preferred.

[0034] Examples of preferred compounds for Nb include (NH4)Nb(C2O4)3 and (NH4)NbO(C2O4)2. Examples of preferred compounds for Mo include MoO3, Na2MoO4 and (NH4)2MoO4.

[0035] Examples of suitable compounds for W include WO3, WO3·H2O, Na2WO4, ammonium tungstate, and tungstic acid.

[0036] Step (b) includes combining solution (α1), solution (β), at least one of solutions (α2), (α3), or (α4), and solution (γ) where applicable, in a continuous reactor to produce solid particles of the hydroxide or carbonate of TM, where these solutions are introduced into the continuous reactor at different locations.

[0037] Examples of continuous reactors include plug-flow reactors, particularly continuous stirred-tank reactors. Continuous reactors have an outlet from which the reaction mixture, i.e., the precursor slurried in the mother liquor, is removed from the reactor. In the case of a continuous stirred-tank reactor, an overflow is a preferred embodiment of the outlet.

[0038] In one embodiment, the pH value in step (b) is in the range of 10 to 14. In another embodiment, particularly when producing carbonate according to the method of the present invention, the pH value in step (b) is in the range of 7 to 9.

[0039] That is, in step (b), solution (α1) is combined in the reactor with solution (β), at least one of solutions (α2), (α3), or (α4), and, if applicable, either solution (γ) or (δ). The combination is carried out in the reactor in a manner in which solution (α1), at least one of solutions (α2), (α3), or (α4), and, if applicable, solution (γ) are introduced into the reactor at different locations. In such embodiments, it is preferable that solution (α1), solution (β), at least one of solutions (α2), (α3), or (α4), and, if applicable, either solution (γ) or (δ) are introduced from different inlets.

[0040] In one embodiment of the present invention, step (b) is carried out in a continuous stirred tank reactor. In such an embodiment, it is preferable that solution (α1), at least one of solutions (α2), (α3), or (α4), and, where applicable, solution (γ) or (δ) are introduced from different inlets, for example, from different nozzles. Such inlets can be attached to the lid of the stirred tank reactor. Therefore, it is preferable that the inlets be arranged in a circuit around the stirrer (see Figure 1).

[0041] In one embodiment of the present invention, the distance between the introduction position of the added solution (α1) and the introduction position of the solution (α2), (α3), or (α4) is 6 times or more the hydraulic diameter of the tip of the inlet of the solution (α1).

[0042] The hydraulic diameter is defined as four times the cross-sectional area of ​​the inlet tip divided by the wetted parameter length of the inlet tip.

[0043] In one embodiment of the present invention, the distance between the outlet of the tank reactor and the tip of the inlet of solution (α2), (α3), or (α4) is 15 times or less, preferably 10 times or less, more preferably 6 times or less, and even more preferably 4 times or less, the external hydraulic diameter of the tip of each inlet, and the distance between the outlet of the reactor and the tip of the inlet of solution (α1) is at least 15 times, for example 100 to 200 times, the external hydraulic diameter of the tip of the inlet of solution (α1). Preferably, the tip of the inlet of solution (α2), (α3), or (α4) is at least 2 times the external hydraulic diameter of the tip of each inlet.

[0044] There are various methods for adding solution (β) to a tank reactor.

[0045] In one embodiment, the distance between the tip of the inlet of solution (β) and the respective inlets of solutions (α1), (α2), (α3), and (α4) is at least 10 times the maximum hydraulic diameter of the inlets of solutions (α1), (α2), (α3), and (α4). In embodiments where the tips being compared have different hydraulic diameters, the data refers to the larger hydraulic diameter.

[0046] In another embodiment, the distance between the introduction position of solution (α1) and the introduction position of solution (β) is 12 times or less the hydraulic diameter at the tip of the alkali metal hydroxide inlet pipe. In a preferred embodiment, solutions (α1) and (β) are introduced by a coaxial mixer.

[0047] In one embodiment of the present invention, step (b) is carried out at a temperature in the range of 10 to 85°C, preferably in the range of 20 to 60°C.

[0048] In one embodiment of the present invention, the pH value of the liquid phase is in the range of 10.0 to 14.0. In the context of the method of the present invention, the pH value refers to the pH value of each solution or slurry at 23°C.

[0049] In one embodiment of the present invention, step (b) is carried out at a constant pressure, for example, atmospheric pressure. In another embodiment, step (b) is carried out at a high pressure, for example, 50 bar or less.

[0050] In one embodiment of the present invention, step (b) is carried out in a steady state simultaneously with the addition of solution (α1), solution (β), at least one of solutions (α2), (α3), or (α4), and, if applicable, either (δ), and the resulting slurry is removed from the reactor, for example, by overflow.

[0051] In another embodiment, step (b) is performed in a dynamic state, and the rate of addition of solution (α1), solution (β), and at least one of solutions (α2), (α3), or (α4) is changed during step (b).

[0052] In one embodiment of the present invention, during step (b), stirring is performed at a speed that provides a medium dissipation rate in the range of 0.1 W / kg to 10 W / kg, preferably 0.5 W / kg to 7 W / kg. For example, in the case of a 3.2-liter stirred tank reactor, a typical stirring speed is in the range of 400 rpm to 1000 rpm (revolutions per minute).

[0053] In one embodiment of the present invention, the average residence time is in the range of 30 minutes to 12 hours, preferably in the range of 1 to 8 hours, and more preferably in the range of 2 to 6 hours.

[0054] In one embodiment of the present invention, excess mother liquor is removed from the continuous reactor. The mother liquor contains water and alkali metal salts. Therefore, the counterions are nickel counterions and counterions of metals other than nickel. For example, if nickel sulfate is used as the water-soluble salt of nickel in solution (α1) and sodium hydroxide or sodium carbonate is used in solution (β), the mother liquor contains sodium sulfate. The mother liquor may further contain alkali metal salts of ammonia and / or carboxylic acids.

[0055] By performing step (b), solid particles of hydroxide, carbonate, or oxyhydroxide are generated, and these solid particles are formed into a slurry. Thus, a slurry is obtained.

[0056] In step (c), the particles from step (b) are separated from the liquid phase by a solid-liquid separation method, preferably by filtration or centrifugation. The liquid phase is also called the mother liquor. Filtration can be performed, for example, on a belt filter or in a filter press.

[0057] To remove the mother liquor, it is preferable to wash the filter cake with, for example, water, an alkali metal hydroxide solution, or an alkali metal carbonate solution.

[0058] Filtration may be supported by suction or pressure.

[0059] Step (c) may be carried out at a temperature in which water is in a liquid state, for example, 5 to 95°C, and preferably 20 to 60°C.

[0060] By performing step (c), a solid material is obtained which is a particulate (oxy) hydroxide, carbonate, or oxide of TM. The material typically has a high water content, for example, 1 to 30% by mass, and can be dried to a water content in the range of 100 to 5,000 ppm, for example, in air, at a temperature in the range of 80 to 150°C, or under reduced pressure ("vacuum"), where ppm is by mass. The water content can be determined by drying in a vacuum at a temperature of 100°C until the mass no longer changes. The water content may also be determined by Karl Fischer titration.

[0061] Following step (c) or drying, the particulate (oxy) hydroxide, carbonate, or oxide of TM may be subjected to step (d). Step (d) includes heat treatment of the solid from step (c) in a rotary kiln or flash firing furnace.

[0062] In one embodiment of step (d), the wet solid material is introduced into the rotary kiln by a chute or vibrating chute, by a spiral conveyor or screw conveyor, preferably by a screw conveyor with one or more screws.

[0063] The wet particulate solid then passes through a rotary kiln. As the wet particulate solid is moved, its water content decreases. Preferably, at the end of the method of the present invention, the residual water content is in the range of 50 ppm to 1.5% by mass, preferably 100 to 300 ppm by mass. ppm is parts per million, relative to mass. The residual water content can be determined by Karl Fischer titration.

[0064] In one embodiment of the present invention, the retort length of the rotary kiln is in the range of 1 to 50 m, preferably 5 to 25 m.

[0065] In one embodiment of the present invention, the retort diameter of the rotary kiln is in the range of 0.2 to 4 meters, preferably 1 to 2 meters.

[0066] In one embodiment of the present invention, the ratio of the retort length to the retort diameter is in the range of 5 to 50, preferably 10 to 25.

[0067] In one embodiment of the present invention, the rotary kiln is precisely horizontal. In another embodiment, the rotary kiln is inclined at an angle of inclination of, for example, 0.2 to 7°, and the movement of particulate solid through the rotary kiln is supported by gravity.

[0068] In one embodiment of the present invention, the rotary kiln is operated at a speed of 0.01 to 20 revolutions per minute, preferably 0.5 to 5 revolutions per minute, and in either case, it is operated continuously or intermittently. If operation in intermittent mode is required, for example, it is possible to operate by running 1 to 5 revolutions for 1 to 60 minutes and then stopping again for 1 to 60 minutes.

[0069] The granular material is moved through a rotary kiln along with a gas flow.

[0070] In one embodiment of step (d), the gas flow has an inlet temperature in the range of 0 to 1400°C, preferably 20 or 200 to 1000°C. In embodiments where the gas inlet temperature is 1000°C or higher, a preheating system is required. In embodiments where a preheating system is not required, the inlet temperature corresponds to the ambient temperature.

[0071] In a preferred embodiment, in the first temperature zone, the temperature of the particulate material is in the range of 80 to 130°C, and in the second temperature zone, the temperature is in the range of 200 to 500°C, preferably 200 to 450°C, and more preferably 220 to 300°C. The temperature can be measured by a sensor. At temperatures above 200°C, carbon dioxide is cleaved from the carbonate and / or hydroxyl groups are removed as water, depending on the chemical properties of each solid material. The removal of carbon dioxide and / or water may be complete or partial, with partial removal being preferred. The preferred range for partial removal of carbon dioxide is 60 to 99%, and the preferred range for partial removal of water is 68 to 99%.

[0072] Further aspects of the present invention relate to particulate (oxy) hydroxides, also referred to below as the (oxy) hydroxide of the present invention or the precursor of the present invention. The (oxy) hydroxide of the present invention is a particulate (oxy) hydroxide of TM having a brucite structure, wherein TM contains nickel and at least one metal selected from cobalt, manganese, and aluminum. Preferably, TM contains nickel and at least two of cobalt, manganese, and aluminum.

[0073] The precursor of the present invention has a core-shell structure in which at least one of cobalt, manganese, and aluminum is concentrated in the shell compared to the core, for example, at least 5 mol%, preferably 30 mol%, relative to the total of nickel, cobalt, manganese, and aluminum.

[0074] The precursor of the present invention mainly has a brucite structure exhibiting C19 stacking faults, which result in localized CdCl2 structural regions induced by molecules or ions inserted into a crystal lattice selected from carbonates and sulfates, and counterions of organic acids selected from tartaric acid, citrate, and glycine, with a transition probability of 2-10%, preferably 4-8%. Stacking faults, including the transition probability, can be detected and quantified by X-ray diffraction.

[0075] Furthermore, the (oxy)hydroxide of the present invention has a particle size distribution with a span in the range of 0.9 to 2.0. The particle sizes (D10), (D40), and (D90) are determined by dynamic light scattering.

[0076] In one embodiment of the present invention, TM is of general formula (I) (Ni a Co b Mn c ) 1-d M d (I) (In the formula, a is in the range of 0.5 to 0.95, preferably 0.8 to 0.92.) b is in the range of 0 or 0.025 to 0.5, preferably 0.025 to 0.15. c is in the range of 0 to 0.2, preferably 0 to 0.15. d is in the range of 0 to 0.1, preferably 0 to 0.05. M is selected from Mg, Al, Ti, Zr, Mo, W, and Nb. a+b+c=1 and b+c>0, (or M contains Al and d > 0) It corresponds to.

[0077] TM may contain trace amounts of further metal ions, such as trace amounts of ubiquitous metals like sodium, iron, calcium, or zinc, but such trace amounts are not considered in the specification of this invention. In this context, "trace amount" means an amount of 0.05 mol% or less of the total metal content of TM.

[0078] The precursor of the present invention is particulate (oxy)hydroxide of TM. In the context of the present invention, "(oxy)hydroxide" refers to hydroxides and includes not only stoichiometrically pure hydroxides, but also, in particular, anions other than hydroxide ions, such as oxide ions and carbonate ions, as well as compounds having anions derived from transition metal starting materials, such as acetates or nitrates, and especially sulfates. Oxide ions are derived from partial oxidation, for example, oxygen uptake during drying. Carbonates are derived from the use of industrial-grade alkali metal hydroxides.

[0079] The precursor of the present invention is a particulate material. In one embodiment of the present invention, the precursor has an average particle size D50 in the range of 3 to 20 μm, preferably 4 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are composed of primary particles, and in particular aggregates of primary particles, and the above particle size refers to the particle size of secondary particles.

[0080] The span of the precursor particle size distribution is in the range of 0.9 to 2.0. This span is defined as [(D90)-(D10)] / (D50), where the values ​​of (D90), (D50), and (D10) are determined by dynamic light scattering. Preferably, the particle size distribution is unimodal.

[0081] The precursors of the present invention may have an irregular shape, but in preferred embodiments they have a regular shape, such as elliptical or even spherical. The aspect ratio may be in the range of 1 to 10, preferably 1 to 3, and more preferably 1 to 1.5. The aspect ratio is defined as the ratio of width to length, specifically the ratio of the particle size of the longest dimension to the particle size of the shortest dimension. Perfectly spherical particles have an aspect ratio of 1.

[0082] The (oxy)hydroxide of the present invention is very suitable for producing cathode active materials for lithium-ion batteries, for example, by directly mixing it with a lithium source such as lithium hydroxide or lithium carbonate and then heat-treating it, or by a two-step process in which it is first heated to 300-550°C in the absence of a lithium source, then mixed with a lithium source at room temperature, and the resulting mixture is heat-treated. Such heat treatment may be carried out at 600-1000°C.

[0083] In one embodiment of the present invention, TM is of general formula (I) (Ni a Co b Mn c ) 1-d M d (I) (In the formula, a is in the range of 0.5 to 0.95, b is 0 or in the range of 0.025 to 0.5. c is in the range of 0 to 0.2. d is in the range of 0 to 0.1. M is selected from Mg, Al, Ti, Zr, Mo, W, Nb, and Ta. a+b+c=1 and b+c>0, (or M contains Al and d > 0) It corresponds to.

[0084] The proportion of radially oriented primary particles can be determined, for example, by scanning electron microscopy (SEM) of the cross-section of at least five secondary particles.

[0085] "Essentially radially oriented" means that perfect radial orientation is not required, but in SEM analysis, the deviation from perfect radial orientation is at most 11 degrees, preferably at most 5 degrees.

[0086] In one embodiment of the present invention, the precursor of the present invention is 2 to 70 m 2 Range of / g, preferably 4-50m 2It has a specific surface area (hereinafter also called BET surface area) in the range of / g. The BET surface area can be determined by nitrogen adsorption after gas release of the sample at 120°C for 30 minutes and beyond, according to DIN ISO 9277:2010.

[0087] The precursor of the present invention can be produced by the method of the present invention.

[0088] The precursor of the present invention is very suitable for producing cathode active materials having excellent cyclic behavior, either directly or after pre-dehydration. Such cathode active materials can be produced by mixing the precursor of the present invention with a lithium source, such as Li2O, LiOH, or Li2CO3, either without water or as a hydrate, and calcining at a temperature in the range of 600 to 1000°C. Thus, a further aspect of the present invention is a method of using the precursor of the present invention for the production of cathode active materials for lithium-ion batteries, and another aspect of the present invention is a method for producing cathode active materials for lithium-ion batteries (hereinafter also referred to as calcination of the present invention), the method comprising the steps of mixing particulate transition metal (oxy) hydroxide of the present invention with a lithium source and heat-treating the mixture at a temperature in the range of 600 to 1000°C. Preferably, the ratio of the precursor of the present invention to the lithium source in such a method is selected such that the molar ratio of Li to TM is in the range of 0.95:1 to 1.2:1, more preferably 0.98 to 1.05.

[0089] Particularly advantageous is the precursor obtained after carrying out step (d) (hereinafter also referred to as the oxide of the present invention). Further aspects of the present invention relate to particulate oxides of TM, where, TM comprises nickel and at least one metal selected from cobalt, manganese, and aluminum, and such particulate oxide has a core-shell structure in which at least one of cobalt, manganese, and aluminum is concentrated in the shell, with a particle size distribution having a span in the range of 0.9 to 2.0, and 20 to 100 mm. 2 It has a specific surface area (BET) in the range of / g and an average crystallite size in the range of 100 to 300 Å.

[0090] TM is defined as described above, as well as properties such as average particle size D50 and span. The oxide of the present invention has a rock salt structure instead of a brucite structure.

[0091] The specific surface area (BET) is 20-200 m². 2 / g, preferably 40-120m 2 The range is / g and can be determined by nitrogen adsorption after gas release of the sample at 200°C for 40 minutes and beyond, according to DIN ISO 9277:2010.

[0092] The present invention will be further illustrated by examples and figures (see Figure 1). [Examples]

[0093] Unless otherwise specified, percentages refer to mass percentages. All pH values ​​were determined at 23°C.

[0094] The coprecipitation reaction was carried out in a 250 ml stirred tank reactor (reactor 1) (see Figure 1) equipped with an overflow system, four dosing inlets, and a pH adjustment circuit (not shown in the diagram). The four dosing inlets were arranged in a circuit around the stirrer. Supply inlet C was closest to the overflow. Both inlet pipes C and F were positioned at a distance of 100 times the hydraulic diameter measured from the inlet pipe.

[0095] To measure the elemental distribution of particle size, the precursor of the present invention was embedded in Epofix resin (Struers, Copenhagen, Denmark). Ultrathin samples (~100 nm) for transmission electron microscopy (TEM) were prepared by ultrathin sectioning and transferred to a TEM sample carrier grid. The samples were imaged by TEM using a Tecnai Osiris and Themis Z3.1 instrument (Thermo-Fisher, Waltham, USA) operating at 200 / 300 keV under HAADF-STEM conditions. Chemical composition maps were obtained by energy-dispersive X-ray spectroscopy (EDXS) using a SuperX G2 detector. Images and elemental maps were evaluated using Velox (Thermo-Fisher) and Esprit (Bruker, Billerica, USA) software packages.

[0096] Step (a.1): By dissolving each compound in water, the following aqueous solutions were provided: Solution (α1.1): NiSO4, 1.65ml / kg in water Solution (α1.2): CoSO4, 1.65ml / kg in water Solution (β.1): 25% by mass of NaOH in water Solution (γ.1): 25% by mass of NH3 in water.

[0097] Process (b.1): 6 mL of solution (γ.1) was added to reactor 1. Next, the pH of the solution was adjusted to 12.10 (measured at 23°C) using solution (β.1). Then, the temperature of reactor 1 was set to 55°C. The stirrer was kept running at 700 rpm continuously. At the same time, solution (α1.1) was added from inlet C, (α 1.2 The solution containing (β.1) was introduced from inlet F, solution (β.1) from inlet E, and solution (γ.1) from inlet D. The molar ratio of nickel to cobalt was adjusted to 55:45.

[0098] The molar ratio of ammonia to the total of nickel and cobalt was adjusted to 0.25. The total volumetric flow rate was set to adjust the average residence time to 2.5 hours. The flow rate of (β.1) was adjusted using a pH adjustment circuit to maintain a constant pH of 12.10 in the container. Reactor 1 was operated continuously while maintaining a constant liquid level in the container. The mixed hydroxide of Ni and Co (TM-OH.1) was collected from the container by overflow. The resulting product slurry contained approximately 120 g / l of mixed hydroxide TM-OH.1, with an average particle size (D50) of 8.14 μm and a span of 1.26.

[0099] Due to the addition of Co near overflow, the Co is concentrated outside the TM-OH.1 particles rather than in the shell.

[0100] Process (c.1): TM-OH.1 particles were collected, filtered, washed with deionized water, dried, and sieved with a 30 μm mesh size. The residual sulfur content of the dried TM-OH.1 was 0.21% by mass, and the TM-OH.1 content was 4.41 m 2 The specific surface area (BET) of / g was observed. Furthermore, the TM-OH.1 particles showed a Ni-rich core, followed by a Co-rich transition shell, and then a Ni-rich terminal shell with approximately 5-7 mol% more Ni concentration compared to the Ni content in the Co-rich transition shell, as confirmed by TEM-EDX (see Figures 2 and 3). By applying stacking fault modeling to the measured X-ray diffraction patterns, the determined average crystallite size was 177 Å. Based on the corresponding X-ray diffraction patterns in Figure 4, the transition probability p, in which C19 stacking faults occur due to insertion layers between brucite layers composed of sulfate ions, was determined. car is p car The percentage was 6.2%. Stacking faults result in localized CdCl2 structural regions.

[0101] To convert it into a dehydration precursor, TM-OH.1 was subjected to heat treatment in a phosphorus furnace at 500°C in the absence of a lithium source to obtain mixed oxide particles TMO.1. The specific surface area (BET) of TMO.1 was 46.19 m². 2The concentration was / g. TMO.1 showed an average crystallite size of 152 Å, obtained from the XRD pattern in Figure 5. The aforementioned concentration gradient within the secondary grains of TMO.1 was retained despite the heat treatment. TMO.1 showed a Ni-rich core, then a Co-rich transition shell, and then a Ni-rich shell again, as confirmed by TEM-EDX (see Figures 6 and 7). [Explanation of Symbols]

[0102] Brief description of the drawing: A: Reaction vessel B: Stirring blade C: Inlet for supplying aqueous solution (α1.1) D: Ammonia supply inlet E: Inlet for supplying sodium hydroxide, solution (β.1) F: Inlet for supplying cobalt sulfate aqueous solution, solution (α2.1) G: Baffle

Claims

1. A method for producing particulate (oxy) hydroxides, carbonates, or oxides of TM, wherein TM comprises nickel and at least one metal selected from cobalt, manganese, and aluminum, and the method comprises the following steps: (a) A step of providing an aqueous solution containing a water-soluble salt of Ni (α1), an aqueous solution containing a water-soluble salt of Co (α2), an aqueous solution containing a water-soluble salt of Mn (α3), an aqueous solution containing a water-soluble compound of Al (α4), an aqueous solution containing an alkali metal hydroxide or carbonate (β), and optionally an aqueous solution containing ammonia, an organic acid, or an alkali metal salt thereof (γ), (b) A step of producing solid particles of TM hydroxide or carbonate by combining solution (α1), solution (β), at least one of solutions (α2), (α3), or (α4), and solution (γ) in a continuous reactor, wherein these solutions are introduced into the continuous reactor at different locations. (c) A step of separating the particles from step (b) from the liquid phase by a solid-liquid separation method. Includes, A method in which the distance between the introduction position of solution (α1) and the introduction position of solution (α2), (α3), or (α4) is six times or more the hydraulic diameter at the tip of the inlet of solution (α1).

2. The method according to claim 1, wherein step (b) is carried out in a continuous stirring tank reactor.

3. A particulate mixed transition metal precursor is selected from (oxy) hydroxides, carbonates, and oxides of TM, and TM is of general formula (I) (Ni a Co b Mr c ) 1-d M d (I) (In the formula, a is in the range of 0.5 to 0.95, b is in the range of 0 or 0.025 to 0.

5. c is in the range of 0 to 0.

2. d is in the range of 0 to 0.

1. M is selected from Mg, Al, Ti, Zr, Mo, W, and Nb. a + b + c = 1 and b + c > 0, (or M contains Al and d > 0) The method according to claim 1 or 2, wherein the combination of metals is as follows.

4. The method according to any one of claims 1 to 3, wherein the distance between the outlet of the tank reactor and the tip of the inlet of solution (α2) or (α3) or (α4) is 15 times or less the hydraulic diameter of the tip of each inlet, and the distance between the outlet of the reactor and the tip of the inlet of solution (α1) is at least 15 times the hydraulic diameter of the tip of the inlet of solution (α1).

5. The method according to any one of claims 1 to 4, wherein in step (b), the addition rates of solution (α1) and (α2) or (α3) or (α4) are changed independently of each other in the range of 0.1 to 10 m / s.

6. The method according to any one of claims 1 to 5, wherein in step (b), a soluble compound of metal M selected from Mg, Ti, Zr, Mo, W, and Nb is added as an aqueous solution (δ).

7. The method according to any one of claims 1 to 6, wherein the organic acid in solution (γ) is selected from tartaric acid, citric acid, and glycine.

8. The method according to any one of claims 1 to 7, wherein the method comprises an additional step (d) of heat-treating the solid residue from step (c) in a rotary kiln or flash firing furnace.

9. A particulate (oxy) hydroxide of TM mainly having a brucite structure, wherein TM contains nickel and at least one metal selected from cobalt, manganese, and aluminum, and the particulate (oxy) hydroxide has a core-shell structure in which at least one of cobalt, manganese, and aluminum is concentrated in the shell, and the brucite structure is localized CdCl induced by molecules or ions inserted into a crystal lattice selected from water, carbonate, and sulfate, and counterions of organic acids selected from tartaric acid, citric acid, and glycine. ２ A particulate (oxy) hydroxide exhibiting C19 stacking faults that result in structural regions, having a transition probability of 2 to 10% in the insertion layer, and having a particle size distribution with a span in the range of 0.9 to 2.

0.

10. TM is general formula (I) (Ni a Co b Mr c ) 1-d M d (I) (In the formula, a is in the range of 0.5 to 0.95, b is in the range of 0 or 0.025 to 0.

5. c is in the range of 0 to 0.

2. d is in the range of 0 to 0.

1. M is selected from Mg, Al, Ti, Zr, Mo, W, and Nb. a + b + c = 1 and b + c > 0, (or M contains Al and d > 0) The particulate (oxy) hydroxide according to claim 9, which is a combination of metals.

11. The particulate (oxy) hydroxide according to claim 9 or 10, wherein at least one of cobalt, manganese, and aluminum is concentrated in the shell of the secondary particles by at least 5 mol% relative to the total of nickel, cobalt, manganese, and aluminum, compared to the core.

12. The particulate (oxy) hydroxide according to any one of claims 9 to 11, wherein at least 60 volume percent of the secondary particles consist of primary particles that are essentially oriented radially.

13. A particulate (oxy) hydroxide according to any one of claims 9 to 12, having a water content in the range of 100 to 5,000 ppm, as determined by Karl Fischer titration.

14. A particulate oxide of TM, wherein TM contains nickel and at least one metal selected from cobalt, manganese, and aluminum, and the particulate oxide has a core-shell structure in which at least one of cobalt, manganese, and aluminum is concentrated in the shell, and has a particle size distribution with a span in the range of 0.9 to 2.0, and 20 to 200 m. ２ Particulate oxide having a specific surface area (BET) in the range of / g and an average crystallite diameter in the range of 100 to 300 Å.

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