Powdered material containing hydroxide and method for producing same

Abstract

The present invention relates to a powdered material for preparing a positive electrode active material for a secondary battery comprising a hydroxide or oxyhydroxide of one or more metal elements, where the one or more metal elements comprise at least one of Ni, Co and Mn, where the material comprises secondary particles comprising a plurality of primary particles, wherein the material has a median particle size D50, determined by laser diffraction, of between 3.0 [mu] m and 20.0 [mu] m, and wherein the primary particles have a particle-based thickness distribution, determined by measuring the thickness of the primary particles in an image taken by the SEM, and wherein the thickness distribution has a median thickness of between 180 nm and 600 nm, and wherein the material has a span value (D90-D10) / D50 of at most 0.6, preferably at most 0.4, more preferably at most 0.2.

Description

Technical Field

[0001] The present invention relates to metal hydroxides that can be used as precursors for cathode active materials for secondary battery packs and methods for manufacturing the same. In particular, but not exclusively, the present invention relates to a powdery material comprising hydroxides or oxyhydroxides of at least one or more metal elements, a method for manufacturing a powdery hydroxide or oxyhydroxide material, and a method for manufacturing a positive electrode active material for a secondary battery pack. Background Art

[0002] Lithium-ion secondary battery packs generally include a negative electrode (anode), an electrolyte, and a positive electrode (cathode), and the positive electrode contains a lithium-transition metal oxide as an active material capable of intercalating and desorbing lithium. The lithium-transition metal oxide is usually manufactured from transition metal hydroxides, oxides, or oxyhydroxides, commonly referred to as precursors, successively manufactured in a coprecipitation method, which discloses mixing a metal salt solution and an alkali solution in the presence of a complexing agent.

[0003] Since the cathode material is a key component of a rechargeable battery pack and has a significant impact on the overall performance of the battery pack, in recent years, there have been many studies and developments in this field (including its precursors). Several trends in cathode material development include, among other things, higher energy density, improved stability and cycling performance, and lower cost. One way to improve the properties of the cathode material is to optimize the microstructure of the cathode material, which is directly reflected from the microstructure of its precursor. One way to reduce costs is to provide these precursors through a more efficient and / or lower-cost process, ideally without compromising their quality.

[0004] In view of the above, there is a continuing need for further improvement in precursors and methods for manufacturing precursors. Summary of the Invention

[0005] The present invention aims to provide hydroxides or oxyhydroxides suitable as precursors for cathode active materials with improved properties.

[0006] In a first aspect, the present invention can provide a secondary particle-based powdery material comprising hydroxides or oxyhydroxides of one or more metal elements for preparing a positive electrode active material for a secondary battery pack, wherein the one or more metal elements include at least one of Ni, Co, and Mn. In other words, the present invention provides a secondary particle-based powdery material composite (compound) for preparing a positive electrode active material for a secondary battery pack, the composite being an M-hydroxide or M-oxyhydroxide, where M represents the (multiple) elements and M comprises one or more metal elements, the metal elements including at least one of Ni, Co, and Mn. According to the present invention, the secondary particles comprise a plurality of primary particles.

[0007] wherein the material / composite has a median particle size D50 between 3.0 μm and 20.0 μm determined by laser diffraction,

[0008] wherein the primary particles have a particle-based thickness distribution determined by measuring the thickness of the primary particles in an image taken by SEM, wherein the thickness distribution has a median thickness between 180 nm and 600 nm, wherein the median particle thickness is the corresponding thickness when the cumulative percentage of the thickness distribution reaches 50%, and

[0009] wherein the material / composite has a span value (D90 - D10) / D50 of at most 0.6, preferably at most 0.4, more preferably at most 0.2, and

[0010] wherein the composite has a specific surface area less than or equal to 4.0 m 2 / g and greater than or equal to 1.5 m 2 / g.

[0011] For ease of illustration, such materials / composites according to the present invention are also simply referred to herein as precursors. The precursor according to the present invention has a composition that can be represented by the following general formula: M - O x (OH) 2-x , where 0 ≤ x ≤ 2, and M includes at least one of Ni, Co, and Mn and possibly at least one other element such as impurities such as Na, S, etc.

[0012] According to the present invention, at least some of the secondary particles have such a morphology or microstructure that at least some of the primary particles have more than one surface that forms part of the outer surface of the secondary particle, and at least some of the said surfaces of the primary particles intersect each other, and at least some of the primary particles have a laminated thickness, i.e., the particle-based thickness as described herein, which is the distance of a surface defined between two adjacent surfaces that do not intersect each other.

[0013] The combined characteristics according to the present invention, namely the disclosed ranges of median secondary particle size, median thickness, and span value, can contribute to a low specific surface area of the powdery material, which in turn can contribute to a dense structure of the precursor. Furthermore, since the microstructure of the cathode material usually inherits the microstructure of its precursor, a low surface area of the cathode material is preferred to prevent moisture and carbon absorption upon exposure to air and reduce the risk of side reactions with the electrolyte in the battery pack.

[0014] In addition, the precursors according to the present invention also help to improve the properties of the positive electrode active material made from a powdery material as a precursor. For example, the cathode material made from the precursor according to the present invention shows lower total alkali and moisture absorption. Total alkali and moisture absorption indicate the presence of unwanted surface impurities, which can cause problems when applying the positive electrode active material in an electrochemical cell, such as gelation during the slurry formation process and gasification during the cycling process.

[0015] Viewed from a second aspect, the present invention also provides a method for manufacturing a powdery material comprising a hydroxide or oxyhydroxide of one or more metal elements, preferably the powdery material is the powdery material according to the first aspect of the present invention. The hydroxide or oxyhydroxide is suitable as a precursor of the cathode active material. The one or more metal elements include at least one of Ni, Co, and Mn. In other words, the present invention provides a method for manufacturing a powdery material composite based on secondary particles according to the first aspect of the present invention. The method includes

[0016] - Supplying a stream of a metal salt solution containing the one or more metal elements to a reactor vessel for a period of time,

[0017] - During the period of time, mixing the metal salt solution with an aqueous solution containing one or more alkali metal hydroxides and an aqueous solution of ammonia (NH 3(水) ), thereby precipitating the hydroxides of the one or more metal elements and forming an aqueous slurry containing particles of the hydroxide or oxyhydroxide of the one or more metal elements,

[0018] wherein during the period of time, in the reactor vessel:

[0019] - The pH value of the aqueous slurry is maintained within a certain range that is higher than or equal to 11.5 and lower than or equal to 12.0, preferably higher than or equal to 11.6 and lower than or equal to 11.9, where the pH value of the aqueous slurry is the pH value measured for a sample of the aqueous slurry after cooling to 20 °C,

[0020] - The concentration of NH3(aq) is maintained higher than or equal to 12.0 g / l and preferably lower than or equal to 15.0 g / l, and

[0021] - The temperature of the aqueous slurry is maintained at least 70 °C and at most 99 °C, preferably at least 80 °C and at most 90 °C;

[0022] wherein after the end of the period of time, the aqueous slurry in the reactor vessel is further processed by separating the solid fraction from the liquid fraction and drying the solid fraction to obtain the material / composite.

[0023] The time period can be expressed as T1 - T2, which refers to the time process that starts at time T1, i.e., the start of the time period, and ends at time T2, i.e., the end of the time period.

[0024] The disclosed pH value, NH3 (水) The combination of the ranges of concentration and reaction temperature can result in a precursor having a special morphology and / or properties according to the present invention. In addition, the resulting precursor has a reduced sulfur content. It is beneficial to use a precursor with a reduced sulfur content in the manufacture of the cathode active material, especially during the sintering stage of the manufacturing process.

[0025] Various embodiments according to the present invention are disclosed in the claims and the specification. Unless otherwise explicitly stated, the embodiments and examples described in the claims and the specification can be freely combined with each other. Throughout the description, if any numerical range is provided, the range also includes the endpoint values unless otherwise explicitly stated. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] For further guidance, the drawings are included to better understand the teachings of the present invention, in which:

[0027] Figure 1 A screenshot of the primary particle size analysis for the scanning electron microscope (SEM) image of the secondary particles obtained in Example 3 is shown;

[0028] Figure 2 The SEM image of the particles obtained in Example 3 is shown; and

[0029] Figure 3 The SEM image of the particles obtained in Comparative Example 3 is shown.

[0030] Figure 4 A graph showing the grain boundary distribution orientation difference angles of Precursors B, D, and F from the example section is shown. DETAILED DESCRIPTION

[0031] In the following detailed description, the preferred embodiments are described in detail to enable the practice of the present invention. Although the present invention is described with reference to these specific preferred embodiments, it should be understood that the present invention is not limited to these preferred embodiments. On the contrary, the present invention includes numerous alternatives, modifications, and equivalents, as will become apparent from considering the following detailed description and the drawings.

[0032] As used herein and in the claims, the term "comprising" should not be construed as limited to the means recited thereafter; it does not exclude other elements or steps. It should be construed as specifying the presence of the stated features, integers, steps or components, but does not exclude 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, for the purposes of the present invention, the only relevant components of the composition are A and B. Thus, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of".

[0033] As used herein and in the claims, the term "positive electrode active material" (also referred to as cathode active material) is defined as a material that is electrochemically active in the positive electrode or cathode. The active material should be understood as a material that is capable of capturing and releasing Li ions when subjected to a voltage change over a predetermined period of time.

[0034] As used herein, the term "positive electrode" is defined as a material that contains a positive electrode active material in addition to other components that are not electrochemically active (in particular, a conductive agent such as carbon black or a binder such as PVDF).

[0035] As used herein, the term "NH 3(水) concentration", etc. means the concentration of ammonia in an aqueous solution.

[0036] Hydroxide or hydroxyoxide powdery material

[0037] In a first aspect, the present invention relates to a powdery material comprising a hydroxide or oxyhydroxide of one or more metal elements for preparing a positive electrode active material for a secondary battery pack, wherein the one or more metal elements include at least one of Ni, Co, and Mn. In other words, the present invention provides a powdery material composite based on secondary particles for preparing a positive electrode active material for a secondary battery pack, the composite being an M-hydroxide or M-oxyhydroxide, wherein M comprises one or more metal elements, the metal elements including at least one of Ni, Co, and Mn. According to the present invention. According to the present invention, the secondary particles comprise a plurality of primary particles, wherein the material / composite (i.e., the precursor) has a median particle size D50 determined by laser diffraction between 3.0 μm and 20.0 μm, wherein the primary particles have a particle-based thickness distribution determined by measuring the thickness of the primary particles in an image taken by SEM, wherein the thickness distribution has a median thickness between 180 nm and 600 nm, wherein the median particle thickness is the corresponding thickness when the cumulative percentage of the thickness distribution reaches 50%, wherein the material / composite (i.e., the precursor) has a span value (D90 - D10) / D50 of at most 0.6, preferably at most 0.4, more preferably at most 0.2, and wherein the composite has a specific surface area less than or equal to 4.0 m 2 / g and greater than or equal to 1.5 m 2 / g.

[0038] For ease of illustration, in the present application, the corresponding thickness when the cumulative percentage of the thickness distribution reaches 50% may be denoted as p50. Possibly, in the present application, the corresponding thickness when the cumulative percentage of the thickness distribution reaches 75% may be denoted as p75. In some embodiments, the thickness distribution has a p50 between 200 nm and 580 nm, preferably between 220 nm and 570 nm. In some embodiments, the thickness distribution has a p75 between 225 nm and 800 nm, preferably between 250 nm and 750 nm. The disclosed p50 and / or p75 ranges may indicate a dense structure of the primary particles. As understood by those skilled in the art, the cumulative percentage of the thickness distribution can be measured based on SEM images using suitable software such as ImageJ software (ImageJ 1.52a, National Institutes of Health, USA).

[0039] In some embodiments, the precursor has a specific surface area less than or equal to 3.6 m 2 / g and greater than or equal to 1.6 m 2 / g. As understood by those skilled in the art, the specific surface area can be measured, for example, by the Brunauer - Emmett - Teller (BET) method using, for example, Quantachrome Monosorb.

[0040] In some embodiments, the precursor has a tapped density in the range of 2.0 - 2.2 g / cm 3 . As understood by those skilled in the art, the tapped density can be determined, for example, on a J.Engelsmann Stamping volumeter STAV II instrument.

[0041] In some embodiments, the median particle size D50 of the precursor is between 3.2 μm and 18.0 μm, preferably between 4.0 μm and 15.0 μm. As understood by those skilled in the art, the particle size distribution can be analyzed by using a Malvern Mastersizer 3000 with a Hydro MV wet dispersion unit after dispersing the particles of the sample in an aqueous medium.

[0042] In some embodiments, the precursor comprises: Ni in an amount x, where x ≥ 30.0 mol%, Mn in an amount y, where 0 ≤ y ≤ 70.0 mol%, Co in an amount z, where 0 ≤ z ≤ 40.0 mol%, Al in an amount q, where 0 ≤ q ≤ 10.0 mol%, and one or more additional elements in an amount r, where the additional elements are elements from the list of B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, W, Zn, and Zr, where 0 ≤ r ≤ 5.0 mol%, where x, y, z, q, and r are the amounts expressed in mol% relative to the total molar content of M, and where x + y + z + q + r = 100.0 mol%. The values of x, y, z, r are measured by inductively coupled plasma (ICP) methods. It is understood that the expression ≥0 includes the absence of the element. In some embodiments, where x ≥ 60 mol% or x ≥ 70 mol% or x ≥ 80 mol% or x ≥ 90 mol%. In some embodiments, where y ≥ 20 mol% and / or z ≤ 25 mol%.

[0043] In some embodiments, as determined by automated crystal orientation mapping in TEM, the secondary particles comprise grain boundaries with an angular distribution of misorientation around the

[0001] crystal axis, where the fraction F1 of grain boundaries with a misorientation angle between 55° - 65° is at least 10% of the total fraction F2 of grain boundaries with a misorientation angle between 5° - 105°. Preferably, the fraction F1 is at least 20% of the total fraction F2, such as 20% - 25%.

[0044] Orientation microscopy techniques for characterizing defects (e.g., geometrically necessary dislocations and grain boundaries) in crystalline materials are well-known. For example, such data can be obtained from electron backscatter diffraction (EBSD) methods based on diffraction images obtained by using a scanning electron microscope (SEM). For nanoscale materials, a precession-assisted crystal orientation mapping technique similar to EBSD, namely the commercially available tool "ASTAR", which is a diffraction spot identification technique based on a transmission electron microscope (TEM) and is also known as automated crystal orientation mapping in TEM, can be used. Based on these crystal orientation microscopy techniques (i.e., crystal orientation mapping techniques), the distribution and accumulation of dislocations relative to the nearest grain boundaries can be determined, and the grain boundary characteristics of the material can be studied. An illustrative method for obtaining the orientation difference angle distribution of the precursor is schematized in part K) of the examples of this specification.

[0045] It is generally believed that the microstructure of the precursor is transferred to the cathode active material made therefrom. It has been observed that the cathode active material made from the precursor according to the present invention also contains a characteristic grain boundary orientation difference angle distribution, such that the fraction of grain boundaries with an orientation difference angle between 55° - 65° is dominant.

[0001] An orientation difference angle of 60° ± 5° around the crystal axis means twins, i.e., twin boundaries. Due to the coherent lattice contraction on both sides of the grain boundary, such grain boundaries in the cathode active material hardly cause stress development during charge and discharge processes, which advantageously results in less cracking of the cathode active material and thus better cycle life.

[0046] Method

[0047] In a second aspect, the present invention relates to a method for manufacturing a powdery material comprising a hydroxide or hydroxy-oxide of one or more metal elements, preferably the powdery material is the powdery material according to the first aspect of the present invention. The hydroxide or hydroxy-oxide is suitable as a precursor of a cathode active material. The one or more metal elements include at least one of Ni, Co, and Mn. In other words, the present invention provides a method for manufacturing a powdery material composite based on secondary particles according to the first aspect of the present invention. The method comprises

[0048] - Supplying a stream of a metal salt solution comprising the one or more metal elements to a reactor vessel for a time period (T1 - T2),

[0049] - During the time period (T1 - T2), mixing the metal salt solution with an aqueous solution comprising one or more alkali metal hydroxides and an aqueous solution of ammonia (NH 3(水) ), thereby precipitating the hydroxide of the one or more metal elements and forming an aqueous slurry comprising particles of the hydroxide or hydroxy-oxide of the one or more metal elements,

[0050] wherein during said time period (T1 - T2), in said reactor vessel there are made:

[0051] - the pH value of said aqueous slurry is maintained within a range that is higher than or equal to 11.5 and lower than or equal to 12.0, preferably higher than or equal to 11.6 and lower than or equal to 11.9, wherein the pH value of said aqueous slurry is the pH value measured on a sample of said aqueous slurry after cooling to 20 °C,

[0052] - the concentration of NH3 (水) is maintained higher than or equal to 12.0 g / l and preferably lower than or equal to 15.0 g / l, and

[0053] - the temperature of said aqueous slurry is maintained at at least 70 °C and at most 99 °C;

[0054] wherein after the end of said time period (T2), the aqueous slurry in the reactor vessel is further processed by separating the solid fraction from the liquid fraction and drying the solid fraction to obtain said material / composite (i.e., the precursor).

[0055] As will be understood by the person skilled in the art, the pH value can be measured by using a pH meter, such as a 780 Metrohm meter. As will be understood by the person skilled in the art, the NH 3(水) concentration can be measured by using a commercially available titrator, such as a Metrhom 848 Titrino Plus.

[0056] During the manufacturing process, the precipitated hydroxide may be partially oxidized, depending on the atmosphere of the manufacturing process. Thus, the aqueous slurry may contain oxyhydroxide. Additionally, during drying, the hydroxide or oxyhydroxide particles from the aqueous slurry may be further partially oxidized. It should be noted that the atmosphere conditions are not crucial for achieving the claimed invention.

[0057] In some embodiments, during the time period T1 - T2, the growth rate of the hydroxide precipitated in the reactor vessel is maintained at at most 0.5 μm / hour, more preferably ≤ 0.2 μm / hour, even more preferably ≤ 0.1 μm / hour.

[0058] In some embodiments, an aqueous slurry of seed particles is provided in a reactor vessel before a time period begins at T1. Using seed particles instead of an in-situ seeding method prevents further nucleation, which is less desirable as it can lead to the formation of small particles that tend to agglomerate, which in turn can alter the production quality. Additionally, as the reaction proceeds, more and more crystal surface becomes available, so more material can be fed without the risk of nucleation. According to the present invention, using a seed slurry in combination with the disclosed precipitation facilitates the stable growth of hydroxides on the seeds without further nucleation and agglomeration, such that the aqueous slurry contains hydroxide or oxyhydroxide particles having a desired median particle size with a uniform distribution, and the hydroxide or oxyhydroxide particles have excellent sphericity. When used as a precursor for a cathode material, the excellent sphericity of the hydroxide or oxyhydroxide particles according to the present invention will be retained in the cathode material. In other words, the cathode material also has excellent sphericity. Sphericity is associated with a higher tapped density.

[0059] In some embodiments, the seed particles are particles of a hydroxide or oxyhydroxide of at least one metal element, preferably the at least one metal element comprises at least Ni. According to the present invention, the (multiple) metal elements for the seed particles and for the hydroxide or oxyhydroxide particles can be different, which provides further flexibility in implementing the method of the present invention.

[0060] 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 at T2, the hydroxide or oxyhydroxide particles of the one or more metal elements have a median particle size D50, where the ratio D50 / D’50 is at least 2.00 and preferably at least 3.00. The larger the D50 / D’50 ratio, the better the sphericity of the hydroxide or oxyhydroxide particles that can be obtained. In some embodiments, D’50 is at least 0.10 µm and at most 3.0 µm. In some embodiments, 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. In some embodiments, D’50 is at least 3.0 μm and at most 5.0 μm, 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.

[0061] In some embodiments, D’50 is at least 0.70 µm and at most 4.00 µm, 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, D50 is at least 9.0 µm. In some embodiments, D50 is at most 20.0 μm

[0062] The method for determining the particle size distribution is not particularly limited. However, for example, the size distribution can be determined based on the integral volume value measured using a laser diffraction and scattering type particle size analyzer. As the average particle size, the percentile values D10, D50, and D90 can be used as the values of the particle diameters at 10%, 50%, and 90% respectively in the cumulative distribution, and the span value (D90 - D10) / D50 can be used as a measure of the distribution range.

[0063] In some embodiments, the metal salt solution has a flow rate expressed as a volume per unit time, and the flow rate at time (t) is represented by Equation 1:

[0064]

[0065] where m1 is the mass of the seed particles provided in the reactor vessel, G(t) is the growth rate of the hydroxide or hydroxyoxide particles at time t, where the value of G(t) is greater than 0, Δt is the time period T1 - T2, D’50 is the median particle size of the seed particles, and M Me is the molar mass of the one or more metal elements, c Me is the concentration of the one or more metal elements, and M Me(OH)2 is the molar mass of the hydroxide or hydroxyoxide of the one or more metal elements. Preferably, the value of G(t) is less than or equal to 1.5 um / h, more preferably less than or equal to 1.0 um / h. In some embodiments, the value of G(t) is less than or equal to 0.5 um / h. In some embodiments, the value of G(t) is less than or equal to 0.1 um / h. A smaller value of G(t) can contribute to a lower porosity.

[0066] The value of G(t) can vary depending on the embodiment. In some embodiments, the value of G(t) varies during the time period T1 - T2.

[0067] The upper limit of G(t), i.e., the maximum growth rate of the hydroxide or hydroxyoxide particles, may depend on, for example, the characteristics of the feed pump and the characteristics of the removal system of the liquid portion (i.e., the mother liquor) in the reaction mixture / aqueous slurry.

[0068] In some embodiments, the value of G(t) in the formula does not change during the time period T1 - T2, wherein the flow rate of the metal salt solution continuously increases according to Formula 1, and the growth rate of the hydroxide or oxyhydroxide particles in the slurry is constant during the time 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 can be obtained. In other words, it may be possible to make the precipitation process more stable and controllable. This is especially true when the target median particle size is large (such as at least 10 μm). While other factors remain constant, with the continuous increase in flow rate, compared to a process that is otherwise similar but in which the metal salt solution is fed at a constant rate throughout the precipitation process, the precipitation time can be reduced to half or even a quarter.

[0069] In some embodiments, the temperature of the aqueous slurry in the reactor vessel is at least 75 °C, and preferably at least 80 °C, more preferably at least or equal to 85 °C; and / or the temperature is at most 99 °C, preferably at most 95 °C, and more preferably at most 90 °C.

[0070] In some embodiments, during the time period T1 - T2, the NH 3(水) concentration remains higher than or equal to 7.0 g / l, preferably higher than or equal to 9.0 g / l, more preferably higher than or equal to 11.0 g / l. The disclosed NH 3(水) concentration can promote slower growth of the particle size (i.e., slower precipitation), which will result in a denser structure of the particles.

[0071] In some embodiments, the one or more metal elements in the metal salt solution include: Ni with a content of b, where b ≥ 30.0 mol%, Mn with a content of c, where 0 ≤ c ≤ 70.0 mol%, Co with a content of d, where 0 ≤ d ≤ 40.0 mol%, Al with a content of e, where 0 ≤ e ≤ 10.0 mol%, and one or more additional elements with a content of f, where the additional elements are elements from the list of B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, Si, Sr, Ti, Y, V, W, Zn, and Zr, where 0 ≤ f ≤ 5.0 mol%, and where b, c, d, e, and f are contents expressed in mol% relative to M, and where b + c + d + e + f = 100 mol%, and where the values of b, c, d, e are measured by an inductively coupled plasma (ICP) method. It is understood that the expression ≥0 includes the absence of the element. In some embodiments, b ≥ 60 mol% or b ≥ 70 mol% or b ≥ 80 mol% or b ≥ 90 mol% and / or b ≤ 99.0 mol%. In some embodiments, where c ≥ 20 mol% and / or d ≤ 25 mol%.

[0072] Method-defined product

[0073] In a third aspect, the present invention relates to a hydroxide or oxyhydroxide powdery material obtainable by the method according to the second aspect of the present invention. In other words, the present invention also provides a powdery material composite based on secondary particles obtained by the method according to the second aspect of the present invention. Preferably, the composite is a powdery material composite based on secondary particles according to the first aspect of the present invention. As understood by those skilled in the art, all embodiments related to the hydroxide or oxyhydroxide powdery material according to the first aspect of the present invention and / or the method according to the second aspect of the present invention are applicable, mutatis mutandis, to the hydroxide or oxyhydroxide powdery material obtainable by the method according to the present invention.

[0074] Positive electrode active material

[0075] In a fourth aspect, the present invention relates to a method for manufacturing a positive electrode active material, the method comprising the steps of:

[0076] - Mixing a powdery material (i.e., a powdery material composite based on secondary particles) of a hydroxide or oxyhydroxide containing one or more metal elements according to the first aspect of the present invention, a lithium source, and optionally a dopant source to obtain a mixture,

[0077] - Heating the mixture at a temperature between 650 °C and 1000 °C in an oxidizing atmosphere to obtain the positive electrode active material, and optionally

[0078] - The method further includes a heat treatment step before the mixing, wherein the powdered material is heated at a temperature between 105 °C and 750 °C.

[0079] Use

[0080] In a fifth aspect, the present invention relates to the use of a powdered material of a hydroxide or hydroxyoxide according to the first aspect of the present invention and / or a powdered material of a hydroxide or hydroxyoxide obtainable by the method according to the second aspect of the present invention in a positive electrode active material.

[0081] Examples

[0082] The present invention will be further illustrated below 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. In addition, during all processes of the examples, unless otherwise stated, a reducing atmosphere is ensured by applying a nitrogen gas stream to the reactor vessel during the precipitation reaction.

[0083] Measurement method used in the examples

[0084] A) pH analysis

[0085] The pH value of the sample was measured with a 780 Metrohm meter calibrated with pH 7 and pH 13 standards. The sample was cooled to 20 °C, and the pH was measured from the sample by lowering the pH electrode into the sample and waiting for the pH reading to stabilize.

[0086] B) NH 3(水) Concentration analysis

[0087] The NH 3(水) concentration was measured from the reactor sample by end point titration using a Metrhom 848 Titrino Plus instrument. One milliliter of the sample solution was added to the titration vessel. 30 - 40 ml of deionized water and 1 ml of 1M NaOH were added. The sample was titrated to the end point with 0.1M HCl.

[0088] C) Solid content analysis

[0089] To determine the solid content of the precipitated hydroxide in the aqueous slurry, a sample taken from the aqueous slurry (the "reaction mixture" in the examples) was thoroughly mixed, and 10 - 30 ml of the mixed sample was taken with a pipette onto a filter paper and then filtered onto a washed and weighed 0.8 um membrane. The filtered membrane was rinsed with DI water, then dried and the weight of the dried membrane was measured, from which the solid content was calculated and expressed as the weight of the dried hydroxide per liter of the aqueous slurry (g / l).

[0090] D) Surface area analysis

[0091] The specific surface area (SA) of the example samples was measured by the Brunauer - Emmett - Teller (BET) method using a Quantachrome Monosorb. Before measurement, the powder sample was placed in a sample tube and heated at 90 °C for 2 hours under nitrogen (N2) to remove adsorbed substances. Then the sample was degassed at room temperature for five minutes. The instrument was used to conduct nitrogen adsorption tests at 77 K. By obtaining the nitrogen isothermal adsorption / desorption curve, the total specific surface area of the sample (unit: m 2 / g) was obtained.

[0092] E) Tap density analysis

[0093] The tap density (TD) of the example samples was measured by mechanically tapping a graduated cylinder (100 ml) containing the sample (with a mass W of about 60 - 120 g). After observing the initial powder volume, the graduated cylinder was mechanically tapped for 15 minutes until no further volume (V, unit cm 3 ) or mass (W) change was observed. TD was calculated as TD = W / V. The TD measurement was carried out on a J.Engelsmann Stamping volumeter STAV II instrument.

[0094] F) Secondary particle size distribution (PSD) analysis

[0095] After dispersing the particles of the sample in an aqueous medium, the PSD of the secondary particles was measured using a Malvern Mastersizer 3000 with a Hydro MV wet dispersion unit. To improve the dispersion of the metal hydroxide powder, sufficient ultrasonic irradiation and stirring were applied, and an appropriate surfactant was introduced. The percentile values D10, D50, and D90 are the particle diameter values at 10%, 50%, and 90% respectively in the cumulative distribution. The span value of the hydroxide is the value of (D90 - D10) / D50.

[0096] G) Metal content analysis

[0097] Using an Agilent ICP 720 - OES instrument, the metal content of the hydroxide was measured by inductively coupled plasma - optical emission spectrometry (ICP - OES). 1 g of the powder sample of each example was dissolved in 50 mL of high - purity hydrochloric acid in a conical 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 in the conical flask and the rinsing water were transferred to a 250 mL volumetric flask. Subsequently, the volumetric flask was filled with deionized (DI) water up to the 250 mL mark and then homogenized completely. An appropriate amount of the solution was taken with a pipette and transferred to a 250 mL volumetric flask for a second dilution, where the volumetric flask was filled with an internal standard and 10% hydrochloric acid up to the 250 mL mark and then homogenized. Finally, this solution was used for ICP - OES measurement. The contents of metals such as Ni, Mn, and Co are expressed as mol% relative to the total metal content in the measured hydroxide.

[0098] H) Primary particle size analysis

[0099] The thickness of the primary particles was calculated by using ImageJ software (ImageJ 1.52a, National Institutes of Health, USA) according to the following steps:

[0100] Step 1) Open the file containing the SEM image of the hydroxide material magnified 20,000 times.

[0101] Step 2) Set the scale bar according to the SEM magnification.

[0102] Step 3) Select the "Line" tool and place a line perpendicular to the orientation of the primary particle on the primary particle.

[0103] Step 4) Measure the thickness of the selected primary particle from the "Set Measurement Parameters and Area" box. The thickness is indicated in the "Length" column.

[0104] Step 5) Repeat steps 3 and 4, randomly selecting 90 particles in one image. If the number of particles in one image is less than 90, additional SEM images can be used. Figure 1 An example of the measurement for EX1 is shown.

[0105] Step 6) Process the data in Microsoft Excel or any digital processing software according to the following steps, which are illustrated in Table 1:

[0106] a. Sort the primary particle thicknesses from low to high in the "Thickness" column

[0107] b. Calculate the contribution fraction of each thickness to the total thickness in the "Fraction of Total" column

[0108] c. Calculate the cumulative score in the "Cumulative" column

[0109] d. Calculate p50 and p75 from the two closest cumulative numbers respectively through the linear straight-line equation y = mx + c

[0110] Table 1: Example of p50 and p75 measurements of the dried hydroxide obtained in EX1

[0111]

[0112] I) Surface base analysis

[0113] When measuring the soluble base content by pH titration, two steps are carried out: (a) preparation of the solution and (b) pH titration. The detailed description of each step is as follows:

[0114] Step (a): Preparation of the solution: Immerse the powder in deionized water and stir for 10 minutes in a sealed glass flask containing 100 mL of deionized water. The amount of the positive electrode active material powder is 4 grams. After stirring, in order to dissolve the base, filter the suspension of the powder in water to obtain a clear solution.

[0115] Step (b): pH titration: Take 90 mL of the clear solution prepared in step (a) and carry out pH titration using 0.1M HCl. The flow rate is 0.5 mL / min, and the pH value is recorded every 3 seconds. The pH titration curve (the change of the pH value with the added HCl) shows two distinct equivalence (or inflection) points. The first equivalence point at around pH 7.4 (corresponding to the amount of HCl of EP1) is produced by the reaction of OH - and CO3 2- with H + The second equivalence point at around pH 4.7 (corresponding to the amount of HCl of EP2) is produced by the reaction of HCO3 - with H + It is speculated that the base dissolved in deionized water is LiOH (amount 2*EP1 - EP2) or Li2CO3 (amount 2*(EP2 - EP1)). The values obtained for LiOH and Li2CO3 are the result of the reaction of the surface with deionized water.

[0116] J) Moisture analysis

[0117] The moisture content of the positive electrode active material powder is measured by a Karl Metrohm Fischer coulometer. Place 1 gram of the positive electrode active material powder in a 300°C KF furnace. The evaporated moisture is directed to the KF reactor and analyzed by KF coulometry.

[0118] K) ASTAR method and orientation difference mapping

[0119] First, before focused ion beam (FIB) preparation, the sample was coated with a 10 nm carbon layer (using a Leica EM ACE600 coater). Then, a FIB lamella of the sample was prepared on a Cu Omniprobe TEM grid using a Thermo Fisher Helios FIB-SEM. The final thinning of the sample was completed by using 2 kV. The size of the lamella was approximately 1 x 5 μm and the thickness was approximately 50 - 100 nm.

[0120] The prepared sample was analyzed by using a 200 kV Thermo Fisher Tecnai G2 transmission electron microscope (TEM) equipped with an “ASTAR” tool (automated TEM phase orientation mapping), which includes a precession device “DigiSTAR” P1000 from NanoMEGAS SPRL and Topspin software (NanoMEGAS SPRL version 3.1.1559.0). The specified area of the sample was scanned by an electron beam, and the precession electron diffraction (PED) patterns were acquired by a CCD camera. The PED patterns were obtained with a 20 μm C2 aperture, a spot size equivalent to a beam diameter of approximately 1 nm, a camera length of 6.2 cm, a precession angle of 0.5 degrees, a resolution of 1.4 nm, a 10 nm step size with 5 precessions per frame, and a scanning speed of 0.05 s per frame. The total acquisition time was about 2 - 2.5 hours, depending on the lamella size.

[0121] The obtained data was post-processed by using software DiffGen (ACOM-SIMAP NanoMEGAS SPRL version 2.0.10.960), Index (ACOM-SIMAP NanoMEGAS SPRL version 2.0.10.1552), Mapviewer (ACOM-SIMAP NanoMEGAS SPRL version 2.0.10.474), and OIM Analysis (EDAX version 8.0) to obtain and analyze the crystal orientation maps. The OIM Analysis software was used for cropping, cleaning, filtering, and texture analysis.

[0122] First, clean the orientation map using the grain dilation method with a grain tolerance angle of 5 degrees and a minimum grain size of 5 pixels. Then, filter the orientation map with a grain tolerance angle of 5 degrees, a minimum grain size of 2 pixels, and a minimum confidence index of 10%. Calculate the grain boundary length within each selected angular range from 5 degrees to 105 degrees, with an interval of 10 degrees. The frequency of each selected angular range is the normalized length of the total grain boundary length with an orientation difference from 5 degrees to 105 degrees, and is plotted against the selected angular range to show the characteristic grain boundary orientation differences within the material.

[0123] Comparative Example 1

[0124] Prepare the positive electrode active material CEX1.1 through a solid-state reaction between a lithium source and a precursor according to the following steps:

[0125] 1. Preparation of precursor A: Prepare the starting solution by placing 2.0 L of DI water and 15 mL of 220 g / L NH 3(水) in a 3.65 L reactor, adjusting the temperature in the reactor vessel to 65 °C and maintaining it at this temperature throughout the process. Adjust the pH of the starting solution to a value of 12.9 by adding 230 g / L NaOH (水) solution.

[0126] Next, by adding a metal sulfate solution of 129 g / L NiSO 4(水) , 80 g / L MnSO 4(水) and 80 g / L CoSO 4(水) , 220 g / L NH 3(水) and 230 g / L NaOH (水) solutions, while mixing at a power density of around 30 kW / m 3 for the first 20 hours and at 10 kW / m 3Precipitation reaction is carried out by mixing power densities around. Each metal sulfate solution is added through a static mixer using a separate pump. The amounts of Ni:Mn:Co are 98:2:0 at the start of the process and gradually change to 74.1:20.3:5.6 at the end of the precipitation process. During the reaction, the feed rate of the NaOH solution is adjusted so that the pH value of the reaction mixture in the reactor vessel remains stable at 11.6 to 11.8, and the feed rate of NH3 (water) is adjusted so that the NH3 concentration in the reaction mixture remains stable at 8.0 ± 1 g / L. After 100 minutes from the start of the reaction, it is paused, and the reaction mixture, i.e., the aqueous slurry, is taken out from the reactor vessel. Then 183 mL of the slurry and 1640 mL of the mother liquor are put back into the reactor and precipitation continues. Reactor samples of the reaction mixture are taken every two hours and D50 is measured therefrom. When the D50 of the reactor sample reaches the target value of about 10 µm, the reaction is stopped, and the duration of this process is 56 hours. During this process, a part of the liquid fraction of the reaction mixture is pumped out from the reactor using a concentrator to obtain a slurry with a solid content of 1100 g / L.

[0127] Filter the obtained aqueous slurry of metal hydroxide and wash it with 220 g / L NaOH (水) solution and 60°C DI water. The filter cake is dried in an oven at 120°C for 12 hours to obtain precursor A with a total metal composition of Ni 0.85 Mn 0.10 Co 0.05 .

[0128] 2. Mixing: Mix the precursor A prepared in step 1) with LiOH and Nb2O5 in an industrial blender to obtain a first mixture with 1 mol% Nb and a lithium-to-metal ratio of 1.01.

[0129] 3. Heating: Heat the mixture from step 2) in an oxygen atmosphere at 705°C for 12 hours, followed by grinding and sieving to obtain CEX1.1.

[0130] The positive electrode active material CEX1.2 is prepared according to the same method as CEX1.1, except that the heating temperature in step 3) is 755°C.

[0131] Example 1

[0132] The positive electrode active material EX1.1 is prepared by a solid-state reaction between a lithium source and a precursor according to the following steps:

[0133] 1. Preparation of precursor B: Precursor B is prepared according to the same method as the precursor A prepared in CEX1, except that the temperature in the reactor vessel is maintained at 85°C.

[0134] 2. Mixing: Mix the precursor B prepared in step 1) with LiOH and Nb2O5 in an industrial blender to obtain a first mixture with 1 mol% Nb and a lithium-to-metal ratio of 1.01.

[0135] 3. Heating: Heat the mixture from step 2) in an oxygen atmosphere at 705 °C for 12 hours, followed by grinding and sieving to obtain EX1.1.

[0136] The positive electrode active material EX1.2 is prepared according to the same method as EX1.1, except that the heating temperature in step 3) is 755 °C.

[0137] Comparative Example 2

[0138] The positive electrode active material CEX2.1 is prepared by a solid-state reaction between a lithium source and a precursor according to the following steps:

[0139] 1. Preparation of precursor C: Prepare a starting solution by adding an aqueous slurry of 6 L of DI water, 160 mL of 220 g / L NH3 (aqueous), and 100 mL of 440 g / L containing Ni 0.94 Mn 0.03 Co 0.03 (OH)2 seed particles to a 10 L reactor vessel, adjusting the temperature in the reactor vessel to 75 °C and maintaining it at this temperature throughout the process.

[0140] Next, a precipitation reaction is carried out by adding a metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of Ni:Mn:Co of 94:3:3) at 120 g / L, 220 g / L NH 3(水) and 230 g / L NaOH (水) solutions, while mixing at a power density of about 30 kW / m for the first 6 hours and at a power density of about 20 kW / m 3 for the remaining time of the process step. The feed rate of the metal sulfate solution is 135 mL / h at the beginning and continuously increases to keep the particle growth rate constant at 0.4 μm / h. During the reaction, the feed rate of the NaOH 3 solution is adjusted so that the pH value of the reaction mixture in the reactor vessel remains stable at 11.2 ± 0.1, and the NH (水) solution is adjusted so that the pH value of the reaction mixture in the reactor vessel remains stable at 11.2 ± 0.1, and the feed rate of the NH 3(水)The feed rate keeps the NH3 concentration in the reaction mixture stable at 5.0 ± 1 g / L. Reactor samples of the reaction mixture are taken every two hours and D50 is measured therefrom. When the D50 of the reactor sample reaches the target value of approximately 10.0 µm, the reaction is stopped, and the duration of this process is 12 hours. During this process, a part of the liquid fraction of the reaction mixture is pumped out of the reactor by using an external concentrator, and the solid content of the reaction mixture in the reactor vessel at the end of the process is about 390 g / L.

[0141] The aqueous slurry of the obtained metal hydroxide is filtered and washed with 220 g / L NaOH solution and 60 °C DI water. The filter cake is dried in an oven at 120 °C for 12 hours to obtain precursor C.

[0142] 2. Mixing: Mix the precursor C prepared in step 1) with LiOH, Nb2O5, and Al2O3 in an industrial blender to obtain a first mixture having a lithium-to-metal ratio of 0.52 mol% Nb, 0.5 mol% Al, and 1.03.

[0143] 3. Heating: Heat the mixture from step 2) in an oxygen atmosphere at 700 °C for 12 hours, followed by grinding and sieving to obtain CEX2.1.

[0144] The positive electrode active material CEX2.2 is prepared according to the same method as CEX2.1, except that the heating temperature in step 3) is 720 °C.

[0145] The positive electrode active material CEX2.3 is prepared according to the same method as CEX2.1, except that the heating temperature in step 3) is 740 °C.

[0146] Example 2

[0147] The positive electrode active material EX2.1 is prepared by a solid-state reaction between a lithium source and a precursor according to the following steps:

[0148] 1. Preparation of precursor D: An aqueous slurry containing 6 L DI water, 350 mL 220 g / L NH3(aq), and 400 mL 440 g / L of Ni 0.94 Mn 0.03 Co 0.03 (OH)2 seed particles with a D50 of 5.0 µm are added to a 10 L reactor vessel, the temperature in the reactor vessel is adjusted to 85 °C and maintained at this temperature throughout the process to prepare the starting solution.

[0149] Next, a precipitation reaction is carried out by adding a metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of Ni:Mn:Co = 94:03:03) at 120 g / L, 220 g / L NH 3(水) and 230 g / L NaOH (水) solutions, while mixing at a power density of about 30 kW / m3 for the first 6 hours and at a power density of about 20 kW / m3 for the remaining time of the process step. The feed rate of the metal sulfate solution is 540 mL / h at the beginning and continuously increases to keep the particle growth rate constant at 0.5 μm / h. During the reaction, the feed rate of the NaOH solution is adjusted so that the pH value of the reaction mixture in the reactor vessel is kept stable at 11.7 ± 0.1, and the feed rate of NH3 (water) is adjusted so that the NH3 concentration in the reaction mixture is kept stable at 12.0 ± 1 g / L. Reactor samples of the reaction mixture are taken every two hours and D50 is measured therefrom. When the D50 of the reactor sample reaches the target value of about 10.0 µm, the reaction is stopped, and the duration of the process is 11 hours. During this process, a part of the liquid fraction of the reaction mixture is pumped out of the reactor using an external concentrator, and the solid content of the reaction mixture in the reactor vessel at the end of the process is about 180 g / L.

[0150] The obtained aqueous slurry of metal hydroxide is filtered and washed with 220 g / L NaOH (水) solution and 60°C DI water. The filter cake is dried in an oven at 120°C for 12 hours to obtain precursor D.

[0151] 2. Mixing: Precursor D prepared in step 1) is mixed with LiOH, Nb2O5, and Al2O3 in an industrial blender to obtain a first mixture having a lithium-to-metal ratio of 0.52 mol% Nb, 0.5 mol% Al, and 1.03.

[0152] 3. Heating: The mixture from step 2) is heated in an oxygen atmosphere at 700°C for 12 hours, followed by grinding and sieving to obtain EX2.1.

[0153] The positive electrode active material EX2.2 is prepared according to the same method as EX2.1, except that the heating temperature in step 3) is 720°C.

[0154] The positive electrode active material EX2.3 is prepared according to the same method as EX2.1, except that the heating temperature in step 3) is 740°C.

[0155] Comparative Example 3: Preparation of Precursor E

[0156] By adding an aqueous slurry of 6 L of DI water, 150 mL of 220 g / L NH₃(aq), and 500 mL of 800 g / L Ni 0.65 Mn 0.15 Co 0.20 (OH)₂ seed particles with a D₅₀ of 4.0 µm into a 10 L reactor vessel, adjusting the temperature in the reactor vessel to 65 °C and maintaining it at this temperature throughout the process to prepare the starting solution. The slurry of Ni 0.65 Mn 0.15 Co 0.20 (OH)₂ seed particles with a D₅₀ of 4.0 µm was prepared similarly as described above.

[0157] Next, a precipitation reaction was carried out by adding a metal sulfate solution containing Ni, Mn, and Co (in a stoichiometric molar ratio of Ni:Mn:Co of 65:15:20) at 120 g / L, 220 g / L NH₃(aq), and 230 g / L NaOH solution, while mixing at a power density of about 30 kW / m³ for the first 6 hours and at a power density of about 20 kW / m 3 during the remaining time of the process step. The feed rate of the metal sulfate solution was 375 mL / h at the beginning and continuously increased to maintain a theoretical constant growth rate of the particles of 0.25 µm / h. During the reaction, the feed rate of the NaOH solution was adjusted so that the pH value of the reaction mixture in the reactor vessel was kept stable at 11.4 ± 0.1, and the feed rate of NH₃(aq) was adjusted so that the NH 3(水) concentration in the reaction mixture was kept stable at 4.0 ± 1 g / L. Reactor samples of the reaction mixture were taken every two hours and D₅₀ was measured therefrom. When the D₅₀ of the reactor sample reached the target value of about 10.2 µm, the process step was stopped, and the duration of this process step was 28.5 hours. During this process step, a part of the liquid fraction of the reaction mixture was pumped out of the reactor using a concentrator, and the solid content of the reaction mixture in the reactor vessel at the end of the process step was about 700 g / L.

[0158] Example 3: Precursor F Preparation

[0159] By adding an aqueous slurry of 6 L of DI water, 350 mL of 220 g / L NH₃(aq), and 500 mL of 800 g / L Ni 0.65 Mn 0.15 Co 0.20 (OH)₂ seed particles with a D₅₀ of 4.0 µm into a 10 L reactor vessel, adjusting the temperature in the reactor vessel to 85 °C and maintaining it at this temperature throughout the process to prepare the starting solution.

[0160] Next, a precipitation reaction is carried out by adding a metal sulfate solution containing Ni, Mn and Co (at a stoichiometric molar ratio of Ni:Mn:Co of 65:15:20) at 120 g / L, 220 g / L NH3(aq) and 230 g / L NaOH solution, while mixing at a power density of about 30 kW / m 3 for the first 6 hours and at a power density of about 20 kW / m 3 for the remainder of the process. The feed rate of the metal sulfate solution is 600 mL / h at the start and continuously increases 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 is adjusted so that the pH value of the reaction mixture in the reactor vessel remains stable at 11.8 ± 0.1, and the feed rate of NH3(aq) is adjusted so that the NH 3(水) concentration in the reaction mixture remains stable at 12.0 ± 1 g / L. Reactor samples of the reaction mixture are taken every two hours and D50 is measured therefrom. When the D50 of the reactor sample reaches the target value of about 10.2 µm, the reaction is stopped and the duration of the process is 15 hours. During this process, a part of the liquid fraction of the reaction mixture is pumped out of the reactor using a concentrator, and the solid content of the reaction mixture (which is an aqueous slurry containing hydroxide particles) in the reactor vessel at the end of the process is about 780 g / L.

[0161] Containing Ni 0.65 Mn 0.15 Co 0.20 Preparation of an aqueous slurry of (OH)2 seed particles

[0162] An initial solution is prepared by placing 6 L of DI water, 55 mL of 220 g / L NH3(aq) and 300 mL of an aqueous slurry containing Ni(OH)2 seed particles with a D50 of 1.2 µm at 130 g / L in a 10 L reactor vessel, adjusting the temperature in the reactor vessel to 85°C and maintaining it at this temperature throughout the process.

[0163] Next, a precipitation reaction is carried out by adding a metal sulfate solution containing Ni, Mn and Co (at a stoichiometric molar ratio of Ni:Mn:Co of 65:15:20) at 120 g / L, 220 g / L NH3(aq) and 230 g / L NaOH solution, while mixing at a power density of about 30 kW / m 3 for the first 30 hours and at a power density of about 20 kW / m 3Precipitation reaction is carried out by mixing power densities of around. The feeding rate of the metal sulfate solution is 450 mL / h in the first two hours and 980 mL / h for the rest of the process steps to maintain an average particle theoretical growth rate of 0.08 µm / h. During the reaction, NaOH solution is added to keep the pH value of the reaction mixture in the reactor vessel stable at 11.8 ± 0.1, and the feeding rate of NH3(aq) is adjusted so that the NH 3(水) concentration in the reaction mixture is maintained at 2 to 3 g / L. Reactor samples of the reaction mixture are taken every two hours and D50 is measured therefrom. When the D50 of the reactor sample reaches the target value of 4.0 µm, the process step is stopped, and the duration of this process step is 36 hours. During this process step, a part of the liquid fraction of the reaction mixture is pumped out of the reactor using a concentrator, and the solid content of the reaction mixture in the reactor vessel at the end of the process is about 800 g / L.

[0164] Preparation of an aqueous slurry containing Ni(OH)2 seed particles

[0165] The starting solution is prepared by placing 100 L of DI water and 1.0 L of an aqueous solution of 220 g / L ammonia (NH3(aq)) in a 200 L reactor vessel, adjusting the reactor temperature to 55 °C and maintaining it at this temperature throughout the process. 5.5 M NaOH solution is added to adjust the pH value of the starting solution in the reactor vessel to 12.6 - 12.8.

[0166] Next, a 2 M NiSO4 solution with a feeding rate of 30 L / h, 220 g / L NH3(aq) with a feeding rate of 0.52 L / h, and 5.5 M NaOH solution are continuously added to the reactor vessel. The solution is mixed with a mixer at a power density of around 35 kW / m 3 and NaOH solution is added to keep the pH in the reactor at 12.6 to 12.8 to establish and maintain the precipitation reaction in order to prepare a reaction mixture - aqueous slurry. The NH 3(水) concentration in the reaction mixture is maintained at around 2 g / L. The reaction is carried out in continuous mode. When the reaction reaches a steady state (around 30 hours after the start), an aqueous slurry of nickel hydroxide Ni(OH)2 with a D50 of 1.2 µm (i.e., seed particles) as the reaction product is collected from the overflow of the reactor vessel.

[0167] Dried product of the example

[0168] The reaction mixtures obtained in all the examples (i.e., the aqueous slurries of metal hydroxides) were filtered and washed with 220 g / L NaOH solution and 60 °C DI water. The filter cakes were dried in an oven at 120 °C for 12 hours. Samples of each of precursors B, D, and F were subjected to ASTAR analysis, and the results are shown in Figure 4 below.

[0169] Results

[0170] Table 2. Summary of properties of precursors

[0171]

[0172] Table 3. Summary of properties of positive electrode active materials in examples and comparative examples

[0173]

[0174] Table 2 summarizes the properties of the precursors. Precursors B, D, and F showed significantly thicker primary particles, as indicated by the p50 and p75 numbers, compared to precursors A, C, and E. Precursors B, D, and F showed significantly smaller surface areas compared to precursors A, C, and E. Each of precursors A to D was lithiated to form a positive electrode active material, and their properties are summarized in Table 3.

[0175] Total base and moisture uptake indicated the presence of unwanted surface impurities, which can cause problems such as gelation during the slurry formation process and gasification during cycling when the positive electrode active material is applied in an electrochemical cell.

[0176] The same observations were also made for CEX2.1 to CEX2.3 and EX2.1 to EX2.3, which are positive electrode active materials with a Ni content of about 94 mol%.

Claims

1. A secondary particle-based powdered material composite for preparing a positive electrode active material for a secondary battery pack, the composite being an M-hydroxide or M-hydroxyoxide, where M comprises one or more metal elements among Ni, Co, and Mn, wherein the secondary particles comprise a plurality of primary particles, wherein the composite has a median particle size D50 determined by laser diffraction between 3.0 μm and 20.0 μm, wherein the primary particles have a particle-based thickness distribution determined by measuring the thickness of the primary particles in an image taken by SEM, and the thickness distribution has a median thickness between 180 nm and 600 nm, wherein the composite has a span value (D90 - D10) / D50 of at most 0.6, preferably at most 0.4, more preferably at most 0.2, and wherein the composite has a specific surface area of less than or equal to 4.0 m 2 / g and greater than or equal to 1.5 m 2 / g.

2. The composite according to claim 1, wherein the thickness distribution has a corresponding thickness between 225 nm and 800 nm, preferably between 250 nm and 750 nm, when the cumulative percentage reaches 75%.

3. The composite according to any one of the preceding claims, the composite having a tapped density in the range of 1.5 - 2.5 g / cm 3 and preferably in the range of 1.8 - 2.3 g / m 3 between.

4. The composite according to any one of the preceding claims, the composite comprising: - Ni in an amount x, where x ≥ 30.0 mol%, - Mn in an amount y, where 0 ≤ y ≤ 70.0 mol%, - Co in an amount z, where 0 ≤ z ≤ 40.0 mol%, - Al in an amount q, where 0 ≤ q ≤ 10.0 mol%, and - one or more additional elements in an amount r, where the additional elements are elements from the list of B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, S, Si, Sr, Ti, Y, V, W, Zn, and Zr, and 0 ≤ r ≤ 5.0 mol%, where x, y, z, q, and r are contents expressed in mol% relative to the total molar content of M, and where x + y + z + q + r = 100.0 mol%.

5. The composite according to claim 4, wherein x ≥ 60 mol% or x ≥ 70 mol% or x ≥ 80 mol% or x ≥ 90 mol%; and / or wherein y ≥ 20 mol% and / or z ≤ 25 mol%.

6. The composite according to any one of the preceding claims, wherein the median particle size D50 is between 4.0 μm and 15.0 μm, preferably at least 6.5 μm, for example between 6.5 μm and 12.0 μm.

7. The composite according to any one of the preceding claims, wherein the composite has a specific surface area of less than or equal to 3.6 m 2 / g and greater than or equal to 1.6 m 2 / g.

8. The composite according to any one of the preceding claims, wherein it is determined by an automated crystal orientation map in TEM, the secondary particles comprise grain boundaries with an angular distribution of misorientation around the [0001] crystal axis, and the fraction (F1) of grain boundaries with a misorientation angle between 55° and 65° is at least 10% of the total fraction (F2) of grain boundaries with a misorientation angle between 5° and 105°, preferably the fraction (F1) is at least 20%, such as 20% - 25%, of the total fraction (F2).

9. A method for manufacturing a secondary particle-based powdered material composite according to any one of claims 1 to 8, wherein the method comprises: - Supplying a stream of a metal salt solution containing the one or more metal elements to a reactor vessel for a time period (T1 - T2), - During the said time period (T1 - T2), mix the metal salt solution with an aqueous solution containing one or more alkali metal hydroxides and an aqueous solution of ammonia (NH 3(水) ), thereby forming an aqueous slurry containing hydroxide or oxyhydroxide particles of the said one or more metal elements. wherein during the time period (T1 - T2), in the reactor vessel: - The pH value of the aqueous slurry is maintained within a range that is higher than or equal to 11.5 and lower than or equal to 12.0, preferably higher than or equal to 11.6 and lower than or equal to 11.9, where the pH value of the aqueous slurry is the pH value measured on a sample of the aqueous slurry after cooling to 20°C, -NH3 (水) The concentration of is maintained at higher than or equal to 5.0 g / l and preferably lower than or equal to 15.0 g / l, and - The temperature of the aqueous slurry is maintained at at least 70°C and at most 99°C, wherein after the end of the time period (T2), the aqueous slurry in the reactor vessel is further processed by separating the solid fraction from the liquid fraction and drying the solid fraction to obtain the secondary particle-based powdered material composite.

10. The method according to claim 9, wherein during the time period (T1 - T2), the growth rate of the hydroxide precipitated in the reactor vessel is maintained at at most 0.5 μm / hour, more preferably ≤ 0.2 μm / hour, and even more preferably ≤ 0.1 μm / hour.

11. The method according to claim 9 or 10, wherein before the start of the time period (T1), an aqueous slurry of seed particles is provided in the reactor vessel, and preferably the seed particles in the seed slurry have a particle size distribution with a median particle size D’50 determined by laser diffraction of at least 0.10 μm and at most 3.0 μm.

12. The method according to claim 11, wherein the metal salt solution has a flow rate expressed as a volume per unit time, and the flow rate at time (t) is represented by formula 1: where m1 is the mass of the seed particles provided in the reactor vessel, G(t) is the hydroxide or oxyhydroxide particle growth rate at the time t, where the value of G(t) is greater than 0, Δt is the time period (T1 - T2), D’50 is the median particle size of the seed particles, and M Me is the molar mass of the one or more metal elements, c Me is the concentration of the one or more metal elements, and M Me(OH)2 is the molar mass of the hydroxide or oxyhydroxide of the one or more metal elements. Preferably, the value of G(t) is less than or equal to 1.5 um / h, more preferably less than or equal to 1.0 um / h.

13. The method according to any one of claims 9 to 12, wherein the temperature of the aqueous slurry in the reactor vessel is at least 75°C, and preferably at least 80°C, more preferably at least or equal to 85°C; and / or the temperature is at most 99°C, preferably at most 95°C, and more preferably at most 90°; and / or wherein during said time period (T1-T2), the NH 3(水) concentration remains higher than or equal to 7.0 g / l, preferably higher than or equal to 9.0 g / l, more preferably higher than or equal to 11.0 g / l.

14. The method according to any one of claims 9 to 13, wherein the one or more metal elements in the metal salt solution comprise: - Ni in an amount b, where b ≥ 30.0 mol%, - Mn with a content c, where 0 ≤ c ≤ 70.0 mol%, - Co with a content d, where 0 ≤ d ≤ 40.0 mol%, - Al with a content e, where 0 ≤ e ≤ 10.0 mol%, and - one or more additional elements with a content f, where the additional elements are elements from the list of B, Ba, Ca, Ce, Cr, Fe, La, Mg, Mo, Nb, Si, Sr, Ti, Y, V, W, Zn, and Zr, where 0 ≤ f ≤ 5.0 mol%, and where b, c, d, e, and f are contents expressed in mol% relative to M, and where b + c + d + e + f = 100 mol%.

15. A powdery material composite based on secondary particles obtained by the method according to any one of claims 9 to 14, preferably the composite is a powdery material composite based on secondary particles according to any one of claims 1 to 8.

16. A method for manufacturing a positive electrode active material, the method comprising the steps of: - mixing powdery materials comprising a powdery material composite based on secondary particles according to any one of claims 1 to 8, a lithium source, and optionally a dopant source to obtain a mixture, - heating the mixture in an oxidizing atmosphere at a temperature between 650 °C and 1000 °C to obtain the positive electrode active material, and optionally - the method further comprises a heat treatment step before mixing, wherein the powdery materials are heated at a temperature between 105 °C and 750 °C.

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