Method for producing an aqueous slurry and a method for producing a powdered hydroxide therefrom

Abstract

The present invention relates to a method for producing an aqueous slurry comprising hydroxide or oxyhydroxide particles of one or more elements, the one or more elements including at least one of Ni, Co, and Mn. The method includes supplying a stream of a metal salt solution comprising one or more elements to a reactor vessel for a period of time, and during that period mixing the metal salt solution with an aqueous solution comprising one or more alkali hydroxides to thereby precipitate hydroxides of the one or more elements and form an aqueous slurry comprising hydroxide or oxyhydroxide particles of the one or more elements, wherein the metal salt solution has a flow rate expressed as volume per unit time, the metal salt solution has a concentration of the one or more elements expressed as moles per unit of volume, and the mathematical product of the flow rate and the concentration increases continuously during that period.

Description

[Technical Field]

[0001] Generally, the present invention relates to metal hydroxides that can be used as precursors for negative electrode active materials for secondary batteries and methods for making the same. Specifically, the present invention relates to, but is not limited to, a method for making an aqueous slurry containing hydroxides or oxyhydroxides of at least one or more metal elements, a method for making powdered hydroxides or powdered oxyhydroxides therefrom, and the use of the aqueous slurry or the powdered hydroxides or powdered oxyhydroxides to make positive electrode active materials for secondary batteries. [Background technology]

[0002] Lithium-ion secondary batteries typically include a negative electrode (anode), an electrolyte, and a positive electrode (cathode) containing a lithium transition metal oxide as an active material capable of lithium insertion and desorption. Lithium transition metal oxides are generally prepared from transition metal hydroxides, oxides, or oxyhydroxides, resulting in a co-precipitation process involving the mixing of a metal salt solution with an alkaline solution in the presence of a complexing agent.

[0003] The lithium-ion battery market is expected to be dominated by automotive applications in the future. To be competitive, batteries for automotive applications must be manufactured at the lowest possible cost. The majority of the cost is driven by the active material, and the cost of precursors is reflected in the cost of the active material. Providing these precursors through more efficient and / or cheaper processes, ideally without compromising their quality, can help reduce costs and promote market acceptance of lithium-ion secondary batteries.

[0004] In view of the above, there is a constant need for further improvements in the precursor manufacturing process. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an improved method for making materials that may then be used directly / indirectly as precursors to lithium transition metal cathode materials for positive electrodes. [Means for solving the problem]

[0006] Viewed from a first aspect, the present invention can provide a method for producing an aqueous slurry containing hydroxide or oxyhydroxide particles of one or more elements, including at least one of Ni, Co, and Mn. The hydroxide or oxyhydroxide particles can ultimately be used as a precursor to a lithium transition metal negative electrode active material for a positive electrode. Such a method according to the present invention comprises: - providing a stream of an aqueous metal salt solution containing one or more elements to a reactor vessel for a period of time; During this period, the metal salt solution is mixed with an aqueous solution containing one or more alkali hydroxides and, optionally, with an aqueous ammonia solution (NH 3(aq) ), thereby precipitating hydroxides of the one or more elements and forming an aqueous slurry containing hydroxide or oxyhydroxide particles of the one or more elements; The metal salt solution has a flow rate expressed as volume per unit time, the metal salt solution has a concentration of one or more elements expressed as moles per unit of volume, and the mathematical product of flow rate and concentration increases continuously over a period of time.

[0007] The hydroxide or oxyhydroxide particles of one or more elements according to the present invention have a composition that can be represented by the following general formula: Me—O x (OH) 2-x , where 0≦×≦2, and Me includes at least one of Ni, Co, and Mn, d, and may contain at least one other element such as an impurity such as Na, S, etc.

[0008] A period may be shown as T1 to T2, and refers to a progression of time beginning at time T1, ie, at the beginning of the period, and ending at time T2, ie, at the end of the period.

[0009] According to the present invention, the continuous increase in the mathematical product of flow rate and concentration contributes to a more efficient growth of the precipitated hydroxide to the target median particle size. Furthermore, it contributes to an improvement in production capacity. The concentration of the metal salt solution supplied may be expressed, for example, as moles per milliliter (mol / ml), and the flow rate, which may also be called the feed rate in the context of the present invention, may be expressed, for example, as milliliters per hour (ml / h), and consequently, the mathematical product of flow rate and concentration may be expressed, for example, as moles per hour (mol / h). It can be seen that if the concentration of the metal salt solution supplied is kept constant, the flow rate increases continuously during the period T1-T2. In other words, at any given time T during the period T1-T2, x In this case, the flow rate r x is at an earlier time T y Flow rate at r y greater than r x >r y , T2 ≥ T x >T y ≧T1.

[0010] Therefore, the present invention provides an improved method for the precipitation process of metal hydroxides used as precursors of negative electrode active materials. The precipitation process may typically include feeding an aqueous metal salt solution, a neutralizing agent such as an alkali hydroxide, and a complexing agent such as an ammonium ion donor to a reaction vessel with stirring, and carrying out a crystallization reaction.

[0011] In accordance with the concepts of the first aspect of the invention, there is also provided a second aspect of the invention, which is a method for producing a powdered hydroxide or powdered oxyhydroxide of one or more elements, the method comprising: I) providing an aqueous slurry according to the first aspect of the invention; II) separating the hydroxide or oxyhydroxide particles from a liquid fraction of the aqueous slurry; and III) drying the separated hydroxide or oxyhydroxide particles.

[0012] There is further provided a third aspect of the present invention, which is the use of the aqueous slurry according to the first aspect of the present invention, or the powdered hydroxide or powdered oxyhydroxide according to the second aspect of the present invention, for producing a positive electrode active material for a secondary battery.

[0013] There is further provided a fourth aspect of the present invention, which is a method for producing a cathode active material by using hydroxide or oxyhydroxide particles produced according to the first and second aspects of the present invention.

[0014] Various embodiments according to the present invention are disclosed in the claims and in this specification. The embodiments and examples described in the claims and specification can be freely combined with each other unless expressly stated otherwise. Throughout the description, when any numerical range is provided, the range also includes the endpoints unless expressly stated otherwise.

[0015] For further guidance, drawings are included for a better understanding of the teachings of the present invention. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 shows a schematic timeline of the period T1 to T2. [Figure 2] FIG. 2 shows a scanning electron microscope (SEM) image of the particles obtained from Example 1. [Figure 3] FIG. 3 shows a graph of the feed rate of the metal sulfate solution of the example as a function of reaction time. [Figure 4]FIG. 4 shows a graph of the median particle size of the hydroxides precipitated in the examples as a function of reaction time. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following detailed description, preferred embodiments are described in detail to enable the practice of the invention. While the invention will be described with reference to these particular preferred embodiments, it will be understood that the invention is not limited to these preferred embodiments. On the contrary, the invention includes numerous alternatives, modifications, and equivalents that will become apparent from consideration of the following detailed description and the accompanying drawings.

[0018] When used in the present specification and claims, the term "comprising" should not be interpreted as being limited to the means listed thereafter, nor as excluding other elements or steps. This term should be interpreted as specifying the presence of the stated features, integers, steps, or components as mentioned, but does not preclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to a composition consisting only of components A and B. This means that the only components of the composition relevant in the context of the present invention are A and B. Consequently, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of."

[0019] The term cathode active material (also known as cathode active material) as used herein and in the claims is defined as a material that is electrochemically active within a cathode or cathode. An active material should be understood to be a material that has the ability to capture and release Li-ions when subjected to a voltage change over a period of time.

[0020] As used herein, the term "cathode" is defined as a material that includes a positive electrode active material in addition to other components that are not electrochemically active, particularly a conductive agent such as a binder, such as carbon black or PVDF.

[0021] As used herein, "NH 3(aq) "Concentration of ammonia" or similar terms means the concentration of ammonia in an aqueous solution.

[0022] In a first aspect, the present invention relates to a method for producing an aqueous slurry containing hydroxide or oxyhydroxide particles of one or more elements, including at least one of Ni, Co, and Mn. The hydroxide or oxyhydroxide particles can ultimately be used as a precursor to a lithium transition metal negative electrode active material for a positive electrode. Such a method according to the present invention comprises: - feeding a stream of an aqueous metal salt solution containing one or more elements into a reactor vessel during a time period T1-T2, the time period having a beginning T1 and an end T2; During the period T1 to T2, the metal salt solution is mixed with an aqueous solution containing one or more alkali hydroxides and, optionally, with an aqueous ammonia solution (NH 3(aq) ), thereby precipitating hydroxides of the one or more elements and forming an aqueous slurry containing hydroxide or oxyhydroxide particles of the one or more elements; The metal salt solution is supplied at a flow rate expressed as volume per unit time, the metal salt solution has a concentration of one or more elements expressed as moles per unit volume, and the mathematical product of the flow rate and the concentration increases continuously during a period T1 to T2.

[0023] During the manufacturing process, the precipitated hydroxides may be partially oxidized depending on the manufacturing process atmosphere. Therefore, the aqueous slurry may contain oxyhydroxides. Note that atmospheric conditions are not necessary to achieve the claimed invention.

[0024] According to the present invention, the continuous increase in the mathematical product of flow rate and concentration contributes to more efficient growth of the precipitated hydroxide toward the target median particle size, further contributing to improved production capacity. Furthermore, according to the present invention, the controllability of the supply of metal elements to the reactor vessel during the precipitation reaction is improved. For example, according to the present invention, the controllability of the supply of metal elements is implemented in such a way that a constant growth rate of the median particle size of the hydroxide can be achieved. In other words, the precipitation process can be made more stable and more controllable.

[0025] In some embodiments, at the start of the time period T1, the mathematical product of the flow rate and the concentration is not zero, in other words, at the start of the time period T1, neither the flow rate of the metal salt solution nor the concentration of the metal salt solution is zero.

[0026] 1, it can be seen that if the concentration of the metal salt solution fed into the reactor vessel is kept constant, the flow rate increases continuously during the period T1-T2. In other words, at any given time T x In this case, the flow rate r x is at an earlier time T y Flow rate at r y greater than r x >r y , T2 ≥ T x >T y ≧T1. In some embodiments, the flow rate of the metal salt solution preferably increases continuously during the period T1 to T2, regardless of whether the concentration of the metal salt solution being supplied is held constant as long as the mathematical product of the flow rate and the concentration is continuously increasing. In some embodiments, the function between time and flow rate may be substantially non-linear.

[0027] In some embodiments, the mathematical product of the flow rate and concentration at the end of the time period T2 is at least twice the mathematical product of the flow rate and concentration at the beginning of the time period T1, preferably the mathematical product at the end of the time period T2 is at least 2.5 times the mathematical product at the beginning of the time period T1, and more preferably the mathematical product at the end of the time period T2 is at least three times the mathematical product at the beginning of the time period T1. The greater the mathematical product at the end of the time period T2 compared to the mathematical product at the beginning of the time period T1, the shorter the precipitation time required to achieve the target median particle size.

[0028] In some embodiments, the period T1-T2 continues until the target median particle size of the hydroxide or oxyhydroxide particles of one or more elements is achieved. In other words, at the end of the period T2, the target median particle size of the hydroxide or oxyhydroxide particles is reached. In some embodiments, the period T1-T2 is at least 8 hours, preferably at least 10 hours, to achieve a target median particle size in the range of 7-12 microns.

[0029] In some embodiments, the method further includes establishing or maintaining a pH range of the aqueous slurry in the reactor vessel during the period T1-T2, the pH range being 9.0 or more and 14.0 or less. When growing particles in a precipitation reaction, a pH value higher than 14.0 may result in nucleation of new particles instead of growing existing particles in the reactor vessel. A pH value lower than 9 may result in incomplete precipitation, affecting the efficiency of the process. To further optimize the reaction conditions, the pH value is more preferably 10.0 or more and 13.5 or less, the pH value of the aqueous slurry being measured on a sample of the aqueous slurry at 20°C. Even more preferably, the pH value is at most 12.2, preferably at least 11.5, and most preferably at most 12.1 and at least 11.6, the pH value of the aqueous slurry being measured on a sample of the aqueous slurry at 20°C. In some embodiments, the pH value is in the range of 10.5 to 12.0, preferably 11.0 to 12.0, and within this range, the growth of precipitation particles present in the reactor vessel may be ensured while the nucleation process of new nuclei may be prevented. Controlling the pH value during the precipitation process may be carried out by adjusting the amount of aqueous solution containing one or more alkali hydroxides supplied. As will be understood by those skilled in the art, the pH value can be measured using a pH meter, for example, a 780 Metrohm meter.

[0030] In some embodiments of the manufacturing method according to the present invention, during the period T1-T2, the aqueous slurry in the reactor vessel has a temperature of at least 45°C, preferably at least 75°C, and more preferably at least 85°C. Temperatures below 45°C may result in a more porous structure of the precipitated hydroxide. In some embodiments, the temperature is at most 99°C, preferably at most 95°C, and more preferably at most 90°C. Temperatures above 95°C may increase processability difficulties. When the temperature is at least 75°C, preferably at least 80°C or 80°C, and more preferably at least 85°C or 85°C, undesirable cracking of the hydroxide or oxyhydroxide particles may be prevented.

[0031] In some embodiments of the method according to the present invention, the mixing comprises mixing m of the aqueous slurry. 3 Maximum 40 kW per m of aqueous slurry 3 It is carried out using a maximum mixing energy of 35 kW per m 3 Mixing energy in excess of 40 kW per m of the aqueous slurry may break down the hydroxide or oxyhydroxide particles into smaller pieces. 3 At least 5 kW per m of aqueous slurry, preferably 3 The mixing energy disclosed contributes to obtaining a homogeneous reaction mixture and to avoiding particle agglomeration.

[0032] In some embodiments of the method according to the present invention, during the period T1-T2, NH 3(aq) The method further comprises establishing or maintaining a concentration of at least 1.0 g / L and at most 13.0 g / L of aqueous ammonia (NH 3(aq) ) may be provided in the reaction vessel as a starting solution before the start of the period T1, and additionally or alternatively, aqueous ammonia (NH 3(aq) ) may be fed to the reaction vessel during the period T1-T2. 3(aq)If the particle size of the precipitated hydroxide in the reactor is relatively small, e.g., less than 4 μm or less than 3 μm, a higher NH 3 concentration, e.g., greater than 13.0 g / l, may result in nucleation. 3(aq) Concentration may lead to aggregation, therefore, under these circumstances, it is preferable to use NH 3(aq) The concentration of NH is at least 1.5 g / L and at most 7 g / L, more preferably at least 1.5 g / L and at most 6 g / L, and most preferably at least 2 g / L and at most 4 g / L. On the other hand, when the particle size of the precipitated hydroxide in the reactor is relatively large, for example, 4 μm or more, 3(aq) The concentration of may be towards the higher end of the range of 1.0 g / l to 13.0 g / l, e.g., NH to allow for slower particle size growth (i.e., slower precipitation) leading to a denser structure of particles. 3(aq) The concentration of NH may be at least 7 g / L and at most 13.0 g / L, preferably at least 10 g / L and at most 12.0 g / L. As will be appreciated by those skilled in the art, the concentration of NH 3(aq) The concentration can be measured by using a commercially available titrator, for example, a Metrom 848 Titrino Plus.

[0033] In some embodiments of the method according to the present invention, the one or more alkali hydroxides include NaOH, KOH, LiOH, CsOH, and RbOH, and preferably include at least NaOH.

[0034] In some embodiments of the method according to the present invention, an aqueous slurry containing hydroxide or oxyhydroxide particles of one or more elements has a liquid fraction and a solid fraction, and a portion of the liquid fraction is removed from the reactor vessel during the period T1-T2, and the solid fraction is retained in the reactor vessel during the period T1-T2. In this manner, a narrow size distribution of the hydroxide or oxyhydroxide particles can be achieved. The narrow size distribution refers to the span value of the hydroxide or oxyhydroxide, expressed as (D90-D10) / D50, which is typically within the range of <0.8.

[0035] The means for removing a portion of the liquid fraction (i.e., mother liquor) of the aqueous slurry is not particularly limited. However, for example, the removal of a portion of the liquid fraction may be carried out by using a commercially available concentrator, which may be connected to the reactor vessel and has the ability to selectively remove the liquid fraction from the reactor vessel.

[0036] In some embodiments of the method according to the present invention, an aqueous slurry of seed particles is provided in the reactor vessel before the start of the time period T1. Using seed particles instead of an in-situ seeding process can prevent further nucleation, which is undesirable because further nucleation can lead to the formation of small particles prone to agglomeration, resulting in variable production quality. Also, due to the more available crystal surface as the reaction progresses, more material can be supplied without the risk of nucleation. According to the present invention, the use of a seed slurry combined with the disclosed precipitation contributes to the steady growth of hydroxides on the seeds without further nucleation and agglomeration, so that the aqueous slurry contains hydroxide or oxyhydroxide particles with a homogeneously distributed desired median particle size, and the hydroxide or oxyhydroxide particles have excellent sphericity. The excellent sphericity of the hydroxide or oxyhydroxide particles according to the present invention remains in the cathode material when it serves as a pre-curing agent for the cathode material. In other words, the cathode material also has excellent sphericity. Sphericity is related to a higher tap density.

[0037] In some embodiments, the seed particles are hydroxide or oxyhydroxide particles of at least one metal element, preferably at least one metal element comprising Ni. According to the present invention, the metal elements for the seed particles and the hydroxide or oxyhydroxide particles may be different metal elements, which provides additional flexibility in implementing the manufacturing method of the present invention.

[0038] In some embodiments of the method according to the present invention, the seed particles have a median particle size D'50, and at the end of the time period T2, the hydroxide or oxyhydroxide particles of one or more elements have a median particle size D50, with the ratio D50 / D'50 being at least 2.00, preferably at least 3.00. The larger the D50 / D'50 ratio, the better the sphericity of the hydroxide or oxyhydroxide particles may be obtained. In some embodiments, D'50 is at least 0.70 μm and at most 3.00 μm, and D50 is at least 3.0 μm and preferably at most 5.0 μm. In some embodiments, D'50 is at least 3.0 μm and at most 5.0 μm, and D50 is at least 8.0 μm. In some embodiments, D50 is at most 15.0 μm, preferably at most 13.0 μm, and more preferably at most 12.0 μm.

[0039] In some embodiments, D'50 is at least 0.70 μm and at most 4.00 μm, and D50 is at least 4.0 μm and preferably at most 18.0 μm. In some embodiments, D'50 is at least 4.0 μm and at most 8.0 μm, and D50 is at least 9.0 μm. In some embodiments, D50 is at most 20.0 μm.

[0040] The method for determining particle size distribution is not particularly limited.However, for example, size distribution can be determined based on the comprehensive volume value measured using laser diffraction and scattering type particle size analyzer.As the average particle size, percentile values ​​D10, D50 and D90 can be used as the particle diameter values ​​at 10%, 50% and 90% of cumulative distribution, respectively, and the span value of (D90-D10) / D50 can be used as the measurement value of distribution range.

[0041] In some embodiments in which an aqueous slurry of seed particles is provided in a reactor vessel, the concentration of one or more elements in the metal salt solution is held constant during a period T1-T2, and the flow rate of the metal salt solution (in L / h) at an instant t during the period T1-T2 is represented by the following equation:

number

[0042] In some embodiments, the value of G(t) is 1.0 μm / h or less. In some embodiments, the value of G(t) is 0.5 μm / h or less. In some embodiments, the value of G(t) is 0.1 μm / h or less.

[0043] The value of G(t) may vary depending on the embodiment, and in some embodiments, the value of G(t) varies during the period T1 to T2.

[0044] The upper limit of G(t), the maximum growth rate of the hydroxide or oxyhydroxide particles, may depend, for example, on the characteristics of the feed pump and the characteristics of the removal system for the liquid portion of the reaction mixture / aqueous slurry (i.e., mother liquor).

[0045] In some embodiments, the value of G(t) in the equation does not change during the period T1-T2, the flow rate of the metal salt solution is continuously increased according to Equation 1, and the growth rate of the hydroxide or oxyhydroxide particles in the slurry is constant during the period T1-T2. Thus, by continuously increasing the flow rate of the metal salt solution, a constant growth rate of the median particle size of the hydroxide or oxyhydroxide may be obtained. In other words, it may be possible to make the precipitation process more stable and controllable, especially when the target median particle size is large, such as at least 10 μm. With continuously increasing the flow rate, precipitation time may be reduced by up to one-half or one-quarter compared to an otherwise similar process, while other factors remain constant, while the metal salt solution is supplied at a constant rate throughout the precipitation process.

[0046] In some embodiments of the method according to the present invention, the one or more elements in the hydroxide or oxyhydroxide particles are Ni with a content x of Ni, where 5.0 mol%≦99 mol%, - Co with a content y of Co, where 0≦y≦30.0 mol%; - Mn with a content z, where 0≦z≦85.0 mol%, Al with a content q, where 0≦q≦10.0 mol%, one or more additional elements in a content r, the additional elements being from the list B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, Si, Sr, Ti, Y, V, W, Zn, Na, S, and Zr, with 0≦r≦5.0 mol%, x, y, z, q, and r are the contents of one or more elements in the hydroxide or oxyhydroxide particles, expressed in mol%, relative to the total molar content, and x + y + z + q + r = 100 mol%, preferably x ≥ 60.0 mol%, z ≤ 30.0 mol%, and (y + z) ≥ 1.0 mol%, more preferably x ≥ 70.0 mol%, also preferably x ≥ 80.0 mol%, or z ≥ 50.0 mol%, and preferably r ≤ 3.0 mol%, and / or z ≥ 60.0 mol%, and / or z ≤ 90.0 mol%, preferably z ≤ 85.0 mol%. The values ​​x, y, z, q, and r are measured by inductively coupled plasma (ICP) method. It can be understood that the expression ≥ 0 also includes the absence of an element.

[0047] According to the present invention, there is also provided a method for producing powdered hydroxides or powdered oxyhydroxides of one or more elements, the method comprising: I) providing an aqueous slurry according to the method of the present invention described above; II) separating the hydroxide or oxyhydroxide particles from the liquid fraction of the aqueous slurry; and III) drying the separated hydroxide or oxyhydroxide particles.

[0048] During the manufacturing process, the hydroxide or oxyhydroxide particles from the aqueous slurry may be further partially oxidized.

[0049] For example, a precursor containing Ni, Co, and Mn in a molar ratio of x:y:z can be prepared in mixed form by a precipitation reaction using the following steps: (1) providing a seed slurry (which may be performed by continuous precipitation) according to the described invention, followed by batch precipitation of the mixed hydroxide in a reactor with NaOH and mixed metal salts under controlled pH; (2) removing and filtering the precursor suspension; and (3) drying the filtered wet cake. In step (1), the mixed salts may be mixed sulfates, and the pH may typically be 11-12. Effective precursor drying is typically carried out at approximately 100°C for a certain period of time to remove most of the water. The typical moisture content after drying is less than 1 wt%, which can be measured at 250°C by the well-known Karl Fischer titration method (ASTM D6869). Before drying, the precursor has a pure or ideal hydroxide crystal structure (having the space group P-3m1).

[0050] In the method according to the invention, drying of the hydroxide or oxyhydroxide precursor can be carefully carried out under well-defined conditions such as temperature, gas atmosphere, and time, which are conditions that can interact, e.g., higher drying temperatures require less time to obtain the desired product, especially for mass production scales.

[0051] The dried hydroxide or oxyhydroxide particles according to the present invention, i.e., powdered hydroxide or powdered oxyhydroxide, can be used to prepare a positive electrode active material. The powdered hydroxide or powdered oxyhydroxide can be mixed with a lithium source to obtain a mixture. The mixture is sintered at a temperature of 650°C to 1000°C. Optionally, a heat treatment at a temperature of 105°C to 750°C can be carried out before mixing.

[0052] Therefore, the present invention also relates to the use of an aqueous slurry comprising hydroxide or oxyhydroxide particles obtainable by the method according to the first aspect of the present invention, and to the use of a powdered hydroxide or powdered oxyhydroxide obtainable by the second aspect of the present invention for producing a positive electrode active material for a secondary battery. [Example]

[0053] The present invention will be further illustrated with reference to some examples and comparative examples. In all examples, the pH value refers to the value measured at a temperature of 20°C. Furthermore, in all processes of the examples, unless otherwise indicated, a reducing atmosphere was ensured by applying a flow of nitrogen gas into the reactor vessel during the precipitation reaction.

[0054] Measurement methods used in the examples pH analysis The pH values ​​of the samples were measured by a 780 Metrohm meter calibrated with pH 7 and pH 13 standards. The pH was measured from the samples by cooling them to 20°C and lowering a pH electrode into the sample and waiting until the pH readings were at the same level.

[0055] NH 3(aq) Concentration analysis NH 3(aq) Concentrations were measured from reactor samples by endpoint titration using a Metrom 848 Titrino Plus instrument. One milliliter of sample solution was added to the titration vessel. 30-40 ml of deionized water and 1 ml of 1 M NaOH were added. The sample was titrated to the endpoint with 0.1 M HCl.

[0056] Solid content analysis To determine the solids content of the precipitated hydroxide in the aqueous slurry, a sample taken from the aqueous slurry (referred to as "reaction mixture" in the examples) was mixed thoroughly, and 10-30 ml of the mixed sample was pipetted onto a filter paper, which was further filtered onto a washed and weighed 0.8 μm membrane. The filtered membrane was rinsed with DI water, then dried, and the weight of the dried membrane was measured, from which the solids content, expressed as the weight of dry hydroxide per liter of aqueous slurry, was calculated in g / l.

[0057] surface area analysis The specific surface area (SA) of the sample samples was measured by the Brunauer-Emmett-Teller (BET) method using Quantachrome Monosorb. The powder sample was placed in a sample tube and heated at 90 °C for 2 h under nitrogen (N2) gas before measurement to remove adsorbed species. The sample was then degassed at room temperature for 5 min. The instrument performed nitrogen adsorption tests at 77 K. The total specific surface area of ​​the sample was calculated by obtaining a nitrogen isotherm adsorption / desorption curve. 2 Derived in / g.

[0058] Tapped Density Analysis Tapped density (TD) measurements of the example samples were carried out by mechanically tapping a graduated measuring cylinder (100 ml) containing the sample (with mass W, approximately 60-120 g). After observing the initial powder volume, the additional volume (cm 3 The measuring cylinder was mechanically tapped for 15 min so that no change in volume (V) or mass (W) was observed. TD was calculated as TD = W / V. TD measurements were performed on a J. Engelsmann Stamping volumeter STAV II instrument.

[0059] Particle size distribution (PSD) analysis PSD was measured using a Malvern Mastersizer 3000 with a Hydro MV wetting and dispersion unit after dispersing sample particles in aqueous media. To improve dispersion of the metal hydroxide powders, sufficient ultrasonic irradiation and stirring were applied, and appropriate surfactants were introduced. The percentile values ​​D10, D50, and D90 are the particle diameter values ​​at 10%, 50%, and 90%, respectively, of the cumulative distribution. The span value for hydroxides is (D90-D10) / D50.

[0060] Metal content analysis The metal content of the hydroxides was measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES) using an Agilent ICP 720-OES instrument. One gram of powder sample of each example was dissolved in 50 mL of high-purity hydrochloric acid in an Erlenmeyer flask. The flask was covered with a watch glass and heated on a hot plate at 380 °C until the sample was completely dissolved. After cooling to room temperature, the solution and the Erlenmeyer flask's rinse water were transferred to a 250 mL volumetric flask. The volumetric flask was then filled to the 250 mL mark with deionized (DI) water, followed by thorough homogenization. An appropriate amount of the solution was pipetted and transferred to a 250 mL volumetric flask for a second dilution. The volumetric flask was filled to the 250 mL mark with 10% hydrochloric acid using an internal standard, followed by homogenization. Finally, this solution was used for ICP-OES measurement. The contents of metals such as Ni, Mn, and Co are expressed as mole percent of the total metal content in the measured hydroxide.

[0061] Example 1 An aqueous slurry of metal hydroxide was prepared according to the following process. In a reactor vessel having a working volume of 8.75 L, 6 L of DI water, 350 mL of 220 g / L NH3(aq), and Ni with a D50 of 4.0 μm were added. 65 Mn 15 Co 20An initiating solution was prepared by adding 515 mL of an 800 g / L aqueous slurry containing (OH)2 seed particles and adjusting the temperature in the reactor vessel to 85°C and maintaining this temperature throughout the process.

[0062] Next, a 120 g / L metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of Ni:Mn:Co of 65:15:20), 220 g / L NH3(aq), and 230 g / L NaOH solution was added, while the reactor was powered at approximately 30 kW / m for the first 6 hours. 3 and for the rest of the process at a power density of approximately 20 kW / m 3 The precipitation reaction was carried out by mixing at a power density of 0.4 μm / h. The feed rate of the metal sulfate solution was initially 600 mL / h and was continuously increased according to Equation 1 disclosed above to keep the particle growth rate constant at 0.4 μm / h (i.e., G(t)=0.4 μm / h). During the reaction, the feed rate of the NaOH solution was adjusted to keep the pH value of the reaction mixture in the reactor vessel stable at 11.8±0.1, and the NH 3(aq) The NH3(aq) feed rate was adjusted to keep the concentration stable at 12.0±1 g / L. Reactor samples of the reaction mixture were taken every 2 hours, and the D50 was measured from them. The reaction was stopped when the D50 of the reactor sample reached the target value of approximately 10.2 μm. The duration of the process was 15 h. A portion of the liquid fraction of the reaction mixture was pumped out of the reactor during the process by using a concentrator. The solids content of the reaction mixture, which was an aqueous slurry containing hydroxide particles in the reactor vessel, was approximately 780 g / L at the end of the process.

[0063] Example 2 An aqueous slurry of metal hydroxide was prepared according to the following process. A reactor vessel with a working volume of 8.75 L was charged with 6 L of DI water, 350 mL of 220 g / L NH3(aq), and Ni with a D50 of 5.0 μm. 94 Mn 03 Co 03An initiating solution was prepared by adding 447 mL of a 440 g / L aqueous slurry containing (OH)2 seed particles and adjusting the temperature in the reactor vessel to 85°C and maintaining this temperature throughout the process.

[0064] Next, a 120 g / L metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of 94:03:03 Ni:Mn:Co), 220 g / L NH3(aq), and 230 g / L NaOH solution was added, while the reactor was powered at approximately 30 kW / m for the first 6 hours. 3 and for the remaining process steps at a power density of approximately 20 kW / m 3 The precipitation reaction was carried out by mixing at a power density of 0.5 μm / h. The feed rate of the metal sulfate solution was initially 540 mL / h and was continuously increased according to the above-disclosed formula 1 to keep the particle growth rate constant at 0.5 μm / h. During the reaction, the feed rate of the NaOH solution was adjusted to keep the pH value of the reaction mixture in the reactor vessel stable at 11.7±0.1, and the NH 3(aq) The NH3(aq) feed rate was adjusted to keep the concentration stable at 12.0±1 g / L. Reactor samples of the reaction mixture were taken every 2 hours, and the D50 was measured from them. The reaction was stopped when the D50 of the reactor sample reached the target value of approximately 10.0 μm. The duration of the process was 11 h. A portion of the liquid fraction of the reaction mixture was pumped out of the reactor during the process by using an external concentrator. The solids content of the reaction mixture in the reactor vessel was approximately 180 g / L at the end of the process.

[0065] Comparative Example 1 An aqueous slurry of metal hydroxide was prepared according to the following process. In a reactor vessel having a working volume of 3.65 L, 1.6 L of DI water, 50 mL of 220 g / L NH3(aq), and Ni with a D50 of 5.0 μm were added. 94 Mn 03 Co 03An initiating solution was prepared by adding 185 mL of a 726 g / L aqueous slurry containing (OH)2 seed particles and adjusting the temperature in the reactor vessel to 85°C and maintaining this temperature throughout the process.

[0066] Next, 120 g / L of a metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of 94:03:03 Ni:Mn:Co), 220 g / L of NH3(aq), and 240 g / L of NaOH solution was added, while approximately 33 kW / m 3 The precipitation reaction was carried out by mixing at a power density of 1000 kJ / s. The feed rate of the metal sulfate solution was kept constant at 400 mL / h. During the reaction, the feed rate of the NaOH solution was adjusted to maintain the pH value of the reaction mixture in the reactor vessel at a stable value of 11.8 ± 0.2, and the feed rate of NH3(aq) was adjusted to maintain the NH3 concentration in the reaction mixture at a stable value of 3.0-4 g / L. Reactor samples of the reaction mixture were taken every 2 hours, and the D50 was measured from them. The reaction was stopped when the D50 of the reactor sample reached the target value of approximately 10.0 μm. The process lasted 10 hours. A portion of the liquid fraction of the reaction mixture was pumped out of the reactor during the process using an external concentrator. The solids content of the reaction mixture in the reactor vessel was approximately 726 g / L at the end of the process.

[0067] Dried products of the examples The reaction mixture, i.e., the aqueous slurry of metal hydroxide obtained in all examples, was filtered and washed with 220 g / L NaOH solution and DI water at 60° C. The filter cake was dried in an oven at 120° C. for 12 hours.

[0068] Overview of the Example Some of the reaction conditions and properties of the aqueous slurries obtained in the examples are illustrated in Table 1. Some of the properties of the dried hydroxides obtained in these examples are illustrated in Table 2. [Table 1] [Table 2]

Claims

1. 1. A method for producing an aqueous slurry comprising hydroxide or oxyhydroxide particles of one or more elements, wherein the one or more elements comprise at least one of Ni, Co, and Mn, the method comprising: - feeding a stream of an aqueous metal salt solution containing said one or more elements into a reactor vessel during a period of time (T1-T2), having a beginning (T1) and an end (T2); - during said period (T1-T2), mixing the metal salt solution with an aqueous solution containing one or more alkali hydroxides, thereby forming said aqueous slurry containing said hydroxide or oxyhydroxide particles of said one or more elements; wherein the metal salt solution is supplied at a flow rate expressed as volume per unit time, the metal salt solution has a concentration of the one or more elements expressed as moles per unit of volume, and the mathematical product of the flow rate and the concentration increases continuously during the period (T1-T2).

2. 2. The method of claim 1, wherein the period (T1-T2) continues until a target median particle size D50 of the hydroxide or oxyhydroxide particles of the one or more elements is obtained.

3. 3. The method of claim 1 or 2, further comprising maintaining a range of pH values ​​of the aqueous slurry in the reactor vessel during the period (T1 to T2), the range being equal to or greater than 9.0 and equal to or less than 14.0, more preferably equal to or greater than 10.0 and equal to or less than 13.5, wherein the pH value of the aqueous slurry is a pH value measured on a sample of the aqueous slurry at 20°C.

4. 4. The process according to any of claims 1 to 3, wherein during said period (T1-T2), said aqueous slurry in said reactor vessel has a temperature of at least 45°C, and preferably at least 75°C, more preferably at least 85°C or equal to 85°C, and / or said temperature is at most 99°C, preferably at most 95°C, and more preferably at most 90°C.

5. The mixing is carried out by mixing the aqueous slurry ３ and / or the mixing energy is at most 40 kW per m3 of the aqueous slurry, preferably at most 35 kW per m3 of the aqueous slurry. ３ At least 5 kW per m of said aqueous slurry, preferably ３ The method according to any one of claims 1 to 4, wherein the power consumption is at least 10 kW per unit area.

6. During the period (T1 to T2), at least 1.0 g / l and at most 13.0 g / l of NH ３（ａｑ） The method of any one of claims 1 to 5, further comprising maintaining a concentration of

7. 7. The method according to any one of claims 1 to 6, wherein at the end of said period (T2), the aqueous slurry comprising the hydroxide or oxyhydroxide particles of the one or more elements in the reactor vessel has a solids content of at least 200 g / l, preferably at least 350 g / l, more preferably at least 600 g / l, even more preferably at least 750 g / l, and most preferably at least 800 g / l.

8. 8. The method according to any one of claims 1 to 7, wherein before the start of said period (T1), an aqueous slurry of seed particles is provided in said reactor vessel, preferably said seeds being particles of a hydroxide or oxyhydroxide of at least one metallic element, preferably comprising at least Ni.

9. the seed particles have a median particle size D'50, and at the end of the period (T2), the hydroxide or oxyhydroxide particles of the one or more elements have a median particle size D50, and the ratio D50 / D ’ 9. The method according to claim 8, wherein D50 is at least 2.00, preferably at least 3.00, and / or D'50 is at least 0.70 μm and at most 3.00 μm, D50 is at least 3.0 μm and preferably at most 5.0 μm, and / or D'50 is at least 3.0 μm and at most 5.0 μm, D50 is at least 8.0 μm, and / or D50 is at most 15.0 μm, preferably at most 13.0 μm, and more preferably at most 12.0 μm.

10. 10. The method of any one of claims 1 to 9, wherein the mathematical product of the flow rate and the concentration at the end of the period (T2) is at least twice the mathematical product of the flow rate and the concentration at the start of the period (T1), preferably the mathematical product at the end of the period (T2) is at least 2.5 times the mathematical product at the start of the period (T1), and more preferably the mathematical product at the end of the period (T2) is at least 3.0 times the mathematical product at the start of the period (T1).

11. The one or more elements in the hydroxide or oxyhydroxide particles are Ni with a content x, where 5.0 mol%≦99 mol%; - Co with a content y, where 0≦y≦30.0 mol%, - Mn with a content z, where 0≦z≦85.0 mol%, - Al with a content q, where 0≦q≦10.0 mol%, one or more additional elements in a content r, said additional elements being from the list B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, Si, Sr, Ti, Y, V, W, Zn, Na, S, and Zr, with 0≦r≦5.0 mol%, and 11. The method of any one of claims 1 to 10, wherein x, y, z, q, and r are contents expressed as mole % relative to the total molar content of the one or more elements in the hydroxide or oxyhydroxide particles, and x+y+z+q+r=100 mole %.

12. x≧60.0 mol%, z≦30.0 mol%, and (y+z)≧1.0 mol%, more preferably x≧70.0 mol%, and preferably x≧80.0 mol%, or 12. The method according to claim 11, wherein z≧50.0 mol% and preferably r≦3.0 mol% and / or z≧60.0 mol% and / or z≦90.0 mol%, preferably z≦85.0 mol%.

13. the concentration of the one or more elements in the metal salt solution is held constant during the time period (T1 to T2), and the flow rate of the metal salt solution at a moment t within the time period (T1 to T2) is represented by Equation 1: [Equation 1] In the formula, m １ is the mass (grams) of the seed particles provided in the reactor vessel, G(t) is the growth rate of the hydroxide or oxyhydroxide particles at the instant t, where the value of G(t) is not zero, Δt is the period (T1 to T2) in hours h, D'50 is the median particle size of the seed particles in μm, and M Ｍｅ is the molar mass (grams / mole) of the one or more elements, and c Ｍｅ is the concentration (grams / liter) of the one or more elements, and M Ｍｅ（ＯＨ）２ is the molar mass (grams / mol.) of the hydroxide or oxyhydroxide of the one or more elements, and preferably, the value of G(t) is equal to or less than 2 μm / h, more preferably equal to or less than 1.5 μm / h.

14. 14. A method for producing a powdered hydroxide or powdered oxyhydroxide of one or more elements, the method comprising: 1) producing an aqueous slurry comprising hydroxide or oxyhydroxide particles of one or more elements according to any one of claims 1 to 13; 2) separating the hydroxide or oxyhydroxide particles from a liquid fraction of the aqueous slurry; and 3) drying the separated hydroxide or oxyhydroxide particles.

15. 15. A method for producing a cathode active material, the method comprising: 1) producing a powdered hydroxide or powdered oxyhydroxide of one or more elements according to claim 14; 2) mixing the powdered hydroxide or powdered oxyhydroxide with a lithium source to obtain a mixture; and 3) sintering the mixture at a temperature between 650°C and 1000°C.

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