Manganese-containing precursors, cathode active materials thereof, and lithium-ion secondary batteries

Abstract

This invention relates to materials comprising hydroxides or hydroxyoxides of at least one or more metallic elements, and to cathode active materials for lithium-ion secondary batteries. Specifically, this invention relates to a manganese-containing precursor for a cathode active material in a secondary battery, the precursor comprising M and elemental oxygen, wherein M comprises: Ni in an amount x relative to M, wherein 0.0 ≤ x ≤ 50.0 mol%; Mn in an amount y relative to M, wherein 50.0 ≤ y ≤ 90.0 mol%; Co in an amount z relative to M, wherein 0.0 ≤ z ≤ 40.0 mol%; at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, Ta, and W in an amount t relative to M, wherein 0.0 ≤ t ≤ 10.0 mol%; wherein x, y, z, and t are measured by ICP-OES; and wherein x + y + z + t is 100.0 mol%; and wherein the manganese-containing precursor has a content of at least 1.65 g / cm³. 3 The ratio of tapped density TD and specific surface area SSA (at least 12.00) to tapped density SSA / TD, expressed in units (m²). 2 cm 3 ) / g 2 express.

Description

Technical Field

[0001] This invention relates to metal hydroxides that can be used as precursors for cathode active materials in secondary battery packs. In particular, but not exclusively, this invention relates to materials comprising hydroxides or hydroxy oxides of at least one or more metal elements, and cathode active materials for lithium-ion secondary batteries. Background Technology

[0002] Lithium-ion secondary batteries typically consist of a negative electrode (anode), an electrolyte, and a positive electrode (cathode), which contains lithium-transition metal oxides as active materials capable of inserting and extracting lithium. Lithium-transition metal oxides are typically manufactured from transition metal hydroxides, oxides, or hydroxyl oxides (commonly referred to as precursors). These precursors are usually produced via co-precipitation methods, which involve mixing a metal salt solution and an alkaline solution in the presence of a complexing agent. Commonly used metals are transition metals such as nickel, manganese, and cobalt. Methods for manufacturing cathode materials typically involve mixing the precursor material with a lithium source, sintering, and, where necessary, grinding. Examples of such cathode materials include lithium nickel manganese cobalt oxides (abbreviated as NMC, Li-NMC, LNMC, or NCM).

[0003] Because cathode materials play a crucial role in rechargeable batteries and significantly impact overall battery performance, this field, including its precursors, has seen extensive research and development in recent years. Several trends in cathode material development include enhancing capacity retention, achieving higher energy density, improving stability and cycle performance, and reducing costs. Altering the stoichiometry of transition metals can alter the properties of the material, thus providing a method for tuning cathode performance. However, in the case of NMC-based batteries, increasing the nickel content enhances the initial discharge capacity but reduces thermal stability and capacity retention. Besides the high cost, increasing the cobalt content involves replacing high-energy nickel or chemically stable manganese. Conversely, increasing the manganese content leads to a decrease in the capacity performance of the manufactured battery due to the reduced nickel content.

[0004] Therefore, it is necessary to design specific precursors to improve the cathode material in order to solve the above problems.

[0005] Acknowledgments

[0006] This invention was carried out with the support of the Materials / Components Technology Development Project of the Korea Evaluation Institute of Industrial Technology (MOTIE), and funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea). [Project Title: Development of High-Power (High-Discharge-Rate) Lithium-Ion Secondary Batteries with 8C Rate / Project Number: 20011287 / Contribution Rate: 100%] Summary of the Invention This invention aims to provide manganese-rich transition metal composite precursor materials that possess advantageous microstructures for cathode active materials, particularly suitable for high-power battery applications, including electric vehicles. By increasing the tap density and specific surface area of ​​the manganese-rich precursors, the discharge capacity requirements of cathode active materials made from these precursors can be met.

[0007] In a first aspect, the present invention can provide a manganese-containing precursor for a cathode active material in a secondary battery, the precursor comprising M and elemental oxygen, wherein M comprises: - Ni with a content of x relative to M, where 0.0 ≤ x ≤ 50.0 mol%. - Mn with a content of y relative to M, where 50.0 ≤ y ≤ 90.0 mol%. - Co with a content of z relative to M, where 0.0 ≤ z ≤ 40.0 mol%. - Relative to M, at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, Ta, and W, with a content of t, 0.0 ≤ t ≤ 10.0 mol% - Where x, y, z, and t are measured by ICP-OES; and - where x+y+z+t is 100.0 mol%; and The manganese-containing precursor has a content of at least 1.65 g / cm³. 3 The ratio of tapped density (TD) and specific surface area (SSA) of at least 12.00 to tapped density, SSA / TD, expressed in units (m³). 2 cm 3 ) / g 2 Expressed in g / cm³. 3 The tap density can be measured according to the fully standardized method ISO 3953 or the equivalent method ASTM B 527. It is usually expressed in cubic meters (m³). 2 The specific surface area expressed as / g can be measured according to the fully standardized method ISO 9277. The ratio of specific surface area to tap density can be expressed as SSA / TD, with units of (m³). 2 cm 3 ) / g 2 Or equivalent to (m) 2 cc) / g 2 .

[0008] The combined features of the invention, namely the disclosed ranges of transition metal stoichiometry, tap density, and the ratio of specific surface area to tap density, surprisingly contribute to the preservation of battery electrochemical properties such as discharge capacity and valence, even if the precursor has a relatively low amount of nickel.

[0009] Therefore, in a second aspect, the present invention can provide a cathode active material for lithium-ion secondary batteries. The cathode active material comprises lithium-transition metal composite oxide particles formed using a manganese-containing precursor according to a first aspect of the present invention.

[0010] Furthermore, in a third aspect, the present invention can provide a lithium-ion secondary battery comprising a cathode containing a cathode active material according to a second aspect of the present invention.

[0011] The main embodiments are characterized in the independent claims. Various embodiments are disclosed in the dependent claims. Unless otherwise expressly stated, the embodiments and examples described in the claims and specification can be freely combined with each other. Attached Figure Description

[0012] For further guidance, accompanying drawings are included to better understand the teachings of the invention, in which: Figure 1 A and 1B show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Example 1, respectively; Figure 1 C and 1D show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Example 2, respectively; Figure 1 E and 1F show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Example 3, respectively; Figure 1 G and 1H show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Example 4, respectively.

[0013] Figure 2 A and 2B show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Comparative Example 1, respectively; Figure 2 C and 2D show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Comparative Example 2, respectively; Figure 2 E and 2F show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Comparative Example 3, respectively; Figure 2G and 2H show scanning electron microscope (SEM) images of the surface and cross-section of the particles obtained from Comparative Example 4, respectively. Detailed Implementation

[0014] In the following detailed description, preferred embodiments are described in detail to enable the practice of the invention. Although the invention has been described with reference to these specific preferred embodiments, it should be understood that the invention is not limited to these preferred embodiments. Rather, the invention includes numerous alternatives, modifications, and equivalents, as will become apparent from consideration of the following detailed description and drawings. In this specification, if any numerical range is provided, it includes both upper and lower limits unless otherwise expressly stated.

[0015] As used herein and in the claims, the term “comprising” should not be construed as limited to the manner listed thereafter; it does not exclude other elements or steps. It should be interpreted as specifying the presence of the stated features, integers, steps, or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Therefore, the scope of the expression “composition comprising components A and B” should not be limited to compositions consisting solely of components A and B. This means that, for the purposes of this invention, the composition contains only the relevant components A and B. Therefore, the terms “comprising” and “including” encompass the more restrictive terms “consistently composed of” and “composed of”.

[0016] In a first aspect, the present invention can provide a manganese-containing precursor for a cathode active material in a secondary battery, the precursor comprising M and elemental oxygen, wherein M comprises: - Ni with a content of x relative to M, where 0.0 ≤ x ≤ 50.0 mol%. - Mn with a content of y relative to M, where 50.0 ≤ y ≤ 90.0 mol%. - Co with a content of z relative to M, where 0.0 ≤ z ≤ 40.0 mol%. - Relative to M, at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, Ta, and W, with a content of t, 0.0 ≤ t ≤ 10.0 mol% - Where x, y, z, and t are measured by ICP-OES; and - where x+y+z+t is 100.0 mol%; and The manganese-containing precursor has a content of at least 1.65 g / cm³. 3 The ratio of tapped density (TD) and specific surface area (SSA) of at least 12.00 to tapped density, SSA / TD, expressed in units (m³). 2 cm3 ) / g 2 express.

[0017] According to the precursor of the first aspect, it can be derived from the general formula MO. a (OH) 2-a This indicates that 0 ≤ a ≤ 2. As will be readily understood by those skilled in the art, MO is expressed as... a (OH) 2-a Where 0 ≤ a ≤ 2, refers to metal hydroxides, hydroxyl oxides, oxides, or any combination thereof. M can be derived from the general formula Ni. x' Mn y' Co z' A t' It is expressed as x'+y'+z'+t'=1, 0≤x'≤0.5, 0.5≤y'≤0.9, 0≤z'≤0.4, 0≤t'≤0.1, and A is at least one additional element selected from Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, Ta and W.

[0018] Values ​​x, y, z, t, etc., can be measured using inductively coupled plasma optical emission spectrometry (ICP-OES). It is understood that expressions ≥0 in chemical formulas include elements that do not exist.

[0019] Usually expressed in units of g / cm³ 3 The tap density can be measured according to the fully standardized method ISO 3953 or the equivalent method ASTM B 527. As understood by a technician, the tap density can be measured on an instrument such as the J. Engelsmann STAV II tap density meter.

[0020] Usually expressed in units of m 2 The specific surface area expressed as / g can be measured according to the fully standardized method ISO 9277. The ratio of specific surface area to tap density can be expressed as SSA / TD, with units of (m³). 2 cm 3 ) / g 2 Or equivalent to (m) 2 cc) / g 2 As understood by those skilled in the art, specific surface area can be measured, for example, using the Bruno Emmett-Taylor (BET) method with the Quantachrome Monosorb.

[0021] According to the invention, the combined features of the present invention, namely the disclosed ranges of transition metal stoichiometry, tap density, and the ratio of specific surface area to tap density, surprisingly contribute to the preservation of battery electrochemical properties such as discharge capacity and valence, even if the precursor has a relatively low amount of nickel, since it is believed in the prior art that reducing the nickel content in the cathode active material adversely affects the discharge capacity of the battery made therefrom.

[0022] The manganese-containing precursor according to a first aspect of the invention has Ni in a content x of at most 50 mol%, preferably at most 45 mol%, and more preferably at most 40 mol%, and preferably at least 10 mol%, more preferably at least 15 mol%, and most preferably at least 25 mol%. In the disclosed chemical formula Ni... x' Mn y' Co z' A t' In this process, the manganese-containing precursor has a nickel content such that x' is at most 0.5, preferably at most 0.45, and more preferably at most 0.4. Preferably, x' is at least 0.1, more preferably 0.15, and even more preferably at least 0.25. The disclosed lower limit is beneficial for satisfactory capacity.

[0023] The manganese-containing precursor according to a first aspect of the invention has a manganese content y of at least 50 mol%, preferably at least 55 mol%, and more preferably at least 60 mol%. In some embodiments, the content y is at most 80 mol% or at most 70 mol%. In the disclosed chemical formula Ni x' Mn y' Co z' A t' In this process, the manganese-containing precursor has a manganese content such that y' is at least 0.5, preferably at least 0.55, and more preferably at least 0.6. In some embodiments, the manganese-containing precursor has a manganese content such that Ni... x Mn y Co z A t The value of y' in the equation is at most 0.80 or at most 0.70.

[0024] The manganese-containing precursor according to the first aspect of the invention has a cobalt content of at most 40 mol%, preferably at most 20 mol%, z. In the disclosed chemical formula Ni x' Mn y' Co z' A t' In the case of the manganese-containing precursor, the cobalt content is such that z' is at most 0.4, preferably at most 0.2.

[0025] Sodium and sulfur are considered impurities and are commonly found in precursors produced using a co-precipitation method with metal sulfate solution and NaOH solution. Most of the sodium and sulfur are retained during the calcination process of the precursor, thus the final cathode active material contains sodium and sulfur. High levels of impurities can affect the performance of the cathode active material. Preferably, the manganese-containing precursor has a sodium content of up to 100 ppm. Preferably, the manganese-containing precursor has a sulfur content of up to 5000 ppm. However, it is also preferred that the sulfur content is at least 300 ppm, for example at least 450 ppm or at least 1400 ppm.

[0026] The precursor is desired to have a high tap density. According to the present invention, the manganese-containing precursor has a tap density of at least 1.65 g / cm³. 3 Preferably, at least 1.70 g / cm³ 3 The tap density (abbreviated as TD) is high. Since the microstructure and properties of the precursor are typically transferred to the cathode active material, cathode active materials with high tap density prepared from precursors according to the invention can be packed more tightly together in a given volume, resulting in higher energy density in the electrode. Furthermore, cathode active materials with high tap density have fewer void spaces or pores within the electrode structure, which can minimize ion diffusion pathways, allowing for faster ion transport and reducing the likelihood of side reactions or performance degradation. On the other hand, excessively high tap density may lead to limited electrolyte permeation into the electrode material, which can result in poor ion transport and low utilization of the active material, thereby reducing the overall performance of the battery. In some embodiments, the tap density is at most 2.00 g / cm³. 3 Preferably, the tap density is at most 1.90 g / cm³. 3 The most preferred value is at most 1.80 g / cm³. 3 .

[0027] A high specific surface area is desirable in the precursor. According to the present invention, the manganese-containing precursor has such a high specific surface area (abbreviated as SSA) that the ratio of specific surface area to tap density (expressed as SSA / TD) is at least 12.00 (m²). 2 cm 3 ) / g 2 The precursors with high specific surface area according to the invention (provided the SSA / TD ratio is within the range disclosed according to the invention) provide more sites for contact between reactants and materials, and more sites for adsorption of molecules or ions, resulting in enhanced reactivity and adsorption capacity. Cathode active materials made from the precursors with high specific surface area according to the invention can enhance ion diffusion, and this allows for faster charging and discharging, resulting in higher power density and improved performance. In some embodiments, the manganese-containing precursor has a surface area of ​​at least 14.00 (m²). 2 cm 3 ) / g 2 For example, at least 15.00, 16.00, 17.00 or 18.00 (m 2 cm 3 ) / g 2 Preferably at least 20 (m) 2 cm 3 ) / g 2 For example, at least 21.00, 22.00, 23.00, or 24.00 (m 2 cm 3 ) / g 2 The SSA / TD ratio. In some embodiments, the specific surface area is at least 25.00 m². 2 / g, preferably at least 30.00 m 2 / g, more preferably at least 33.00 m 2 / g. On the other hand, excessively high surface area may affect material stability or pose challenges to material handling and processing. In some embodiments, the ratio SSA / TD is at most 30.00, preferably at most 25.00 (m²). 2 cm 3 ) / g 2 In some implementations, the specific surface area is at most 50.00 m². 2 / g, preferably up to 45.00 m 2 / g, more preferably up to 40.00 m 2 / g.

[0028] Materials with high specific surface areas typically possess more porous structures. These pores can act as reservoirs for reactants, enhancing mass transport and improving the overall efficiency of chemical reaction and energy storage processes. In some embodiments, the manganese-containing precursor has a surface area of ​​at least 0.100 cm⁻¹, determined by nitrogen adsorption measurements and calculated according to the BJH method. 3 Total pore volume (TPV) / g. The BJH method (named after Barrett, Joyner, and Halenda) is a well-known procedure in the art for calculating total pore volume. Total pore volume can be measured according to the fully standardized method ISO 15901, which describes a method for evaluating porosity and pore size distribution by gas adsorption. Considering material stability and processability, it is preferred that the TPV determined by the BJH method be at most 0.200 cm³ / g. 3 / g, more preferably up to 0.180 cm 3 / g.

[0029] In some embodiments, the precursor according to the invention has a median particle size D50 of at least 5.00 µm, as determined by laser diffraction; preferably, D50 is at most 12.00 µm, more preferably at most 10.00 µm. As those skilled in the art will understand, after the particles of the sample are dispersed in an aqueous medium, the particle size distribution can be analyzed using a Malvern Mastersizer 3000 with a Hydro MV wet dispersion unit. The combination of the disclosed range of median particle size with the disclosed range of SSA / TD makes the precursor contribute to increased capacity.

[0030] The precursor according to the invention can have a core-shell structure, such that the precursor comprises particles having a core portion and a shell portion surrounding the core portion. The chemical compositions of the core portion and the shell portion can be the same or different. In some embodiments, the core portion contains at least 90 mol% nickel or manganese based on the total mole percent of the core portion.

[0031] The precursor according to the invention can be secondary particles composed of aggregated primary particles. In some embodiments, the primary particles have a particle-based thickness distribution, as determined by measuring the thickness of the primary particles in an image taken by SEM, wherein the thickness distribution has a corresponding thickness between 10 nm and 70 nm, preferably between 20 nm and 50 nm, when the cumulative percentage reaches 75%; and / or when the cumulative percentage reaches 50%, the thickness distribution has a corresponding thickness between 10 nm and 70 nm, preferably between 20 nm and 40 nm. The disclosed range of thickness not only contributes to specific surface area and / or porosity, but also contributes to a uniform and consistent lithium distribution within the cathode material due to the homogeneity of the precursor.

[0032] The method for manufacturing the precursor of the present invention may typically include, for example: - Provide a starting solution containing an aqueous slurry of seed particles in the reactor vessel. - A flow of metal salt solution containing one or more metal elements is supplied to the reactor vessel for a time period T1-T2. - During time period T1-T2, the starting solution, the metal salt solution, and the aqueous solution containing one or more alkali metal hydroxides are mixed to precipitate the hydroxides of one or more metal elements and form an aqueous slurry containing the hydroxides of one or more metal elements; optionally, a complexing agent such as an aqueous ammonia solution may be present in the starting solution and / or during the precipitation process, such that an NH3 concentration of up to 10.0 g / l, preferably up to 5.0 g / l, more preferably up to 1.0 g / l, even more preferably up to 0.5 g / l, and most preferably almost 0 g / l is maintained during the precipitation process.

[0033] During the time period T1-T2: - Adjust the pH of the reaction mixture in the reaction vessel to maintain it below 12, preferably at most 11.7, more preferably between 10.5 and 11.0, for example 10.7-10.8, 10.8-10.9, or 10.7-10.9, wherein the pH value is as measured for an aqueous slurry sample at 20 °C; and - Maintain the O2 content in the reaction vessel atmosphere at a level greater than 0% by volume, for example, greater than 0.5% by volume, or greater than 0% by volume and at most 6% by volume. After time period T2 ends, the aqueous slurry in the reaction vessel is further processed by separating the solid fraction from the liquid fraction and drying the solid fraction to obtain a powdered precursor.

[0034] During the manufacturing process, the precipitated hydroxides can be partially oxidized, depending on the metal content of the metal salt solution and / or the oxidizing atmosphere during the manufacturing process. Therefore, the aqueous slurry may contain hydroxyl oxides. Additionally, during drying, hydroxide or hydroxyl oxide particles from the aqueous slurry may be further partially oxidized.

[0035] As the technician understands, pH can be measured using a pH meter, such as a 780 Metrohm meter. As the technician understands, NH... 3(aq) Concentration can be measured using a commercially available titrator such as the Metrhom 848 TitrinoPlus.

[0036] Methods for manufacturing cathode active materials may include, for example, the following steps: - A mixture is obtained by mixing a powdered precursor material according to a first aspect of the invention, a lithium source, and an optional dopant source. - The mixture is heated in an oxidizing atmosphere at a temperature between 650 °C and 1000 °C, preferably between 700 °C and 925 °C, to obtain a cathode active material, and optionally... The method also includes a heat treatment step prior to mixing, wherein the powdered material is heated at a temperature of 105 °C to 750 °C.

[0037] Example The present invention will be further described below with reference to some embodiments and comparative examples.

[0038] Measurement methods used in the embodiments A) Surface area analysis The specific surface area (SSA) of the sample, cathode active material precursor, and cathode active material final product was measured according to the standard Bruno-Emmett-Teller (BET) method of ISO 9277 on a Quantachrome® Autosorb instrument. Prior to 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. Before BET measurement, the sample was degassed at 200 °C for 6 hours to completely remove moisture. The instrument performed nitrogen adsorption tests at 77 K. The total specific surface area (in m²) of the sample was obtained by obtaining nitrogen isotherm adsorption / desorption curves. 2 / g).

[0039] B) Tap density analysis Tap density (TD) measurements were performed on a J. Engelsmann STAV II tap density meter by mechanically striking a graduated cylinder (100 ml) containing a sample (with mass W, approximately 60-120 g). After observing the initial powder volume, the cylinder was mechanically struck 5000 times according to the tap density measurement procedure of ASTM B-527 until no further volume (V, in cm³) was observed. 3 TD is expressed as a change in volume (W) or mass (W). TD is calculated as TD = W / V.

[0040] C) Secondary Particle Size Distribution (PSD) Analysis After dispersing the sample particles in an aqueous medium, the secondary particle size distribution (PSD) was measured using a Malvern® MasterSizer3000 with a Hydro MV wet dispersion unit. Sufficient ultrasonic irradiation and stirring were applied to improve the dispersion of the metal hydroxide powder, and an appropriate surfactant was introduced. Percentage values ​​D10, D50, and D90 represent the secondary particle diameters at 10%, 50%, and 90% of the cumulative distribution, respectively. The hydroxide span is calculated as (D90 - D10) / D50.

[0041] D) Metal content analysis The amounts of Ni, Co, Mn, Na, and S in the cathode active material precursor powder were measured using inductively coupled plasma optical emission spectrometry (ICP-OES) with an iICAP 6000 (Agilent Technologies). One gram of powder sample was dissolved in 3 mL of high-purity HCl and 3 mL of HNO3 in an Erlenmeyer flask. The flask was covered with a glass lid and heated on a hot plate at 380 °C until the precursor was completely dissolved. After cooling to room temperature, the solution from the Erlenmeyer flask was poured into a 250 mL volumetric flask. The volumetric flask was then filled to the 250 mL mark with deionized water and completely homogenized.

[0042] E) Primary particle size analysis To obtain the thickness-based distribution of the primary particles, the data can be processed in Microsoft Excel or any number of processing software according to the steps shown in Table 1: a. Sort the primary particle thickness from low to high in the "Thickness" column. b. Calculate the contribution score of each thickness to the total thickness in the "Fraction of Total" column. c. Calculate the cumulative score in the "Cumulative" column. d. Calculate p50 and p75 from the two closest cumulative values ​​using the linear equation y=mx+c; where p50 refers to the thickness corresponding to a cumulative percentage of 50%, and p75 refers to the thickness corresponding to a cumulative percentage of 75%.

[0043] Table 1. Examples of p50 and p75 measurements for EX1

[0044] F) Total pore volume analysis The total pore volume of the samples was measured using the standard pore size distribution and porosity method according to ISO 15901, and was performed on a Quantachrome® Autosorb Nova 4200e analyzer.

[0045] G) Content Analysis The amounts of Na and S in the cathode active material precursor powder were measured using inductively coupled plasma optical emission spectrometry (ICP-OES) with an iICAP 6000 (Agilent Technologies). One gram of powder sample was dissolved in 10 mL of high-purity hydrochloric acid (at least 37% by weight HCl relative to the total weight of the solution) in an Erlenmeyer flask. The flask was covered with a glass lid and heated on a hot plate at 380 °C until the precursor was completely dissolved. After cooling to room temperature, the solution in the Erlenmeyer flask was poured into a 250 mL volumetric flask. The volumetric flask was then filled to the 250 mL mark with deionized water and subsequently homogenized completely. The contents of metals such as Ni and Mn were reported as mol% relative to the total molar content of the metals in the sample. The Na and S contents were reported in ppm.

[0046] Example 1 (1) Preparation steps of cathode active material precursor (1a) Seed pulp preparation process First, the starting solution was prepared as follows: 10 L of DI water, 0.1 L of 55 g / L ammonia solution, and 0.1 L of 220 g / L NaOH solution were placed in a 30 L reaction vessel equipped with a turbine impeller located 50 mm from the bottom of the vessel. The reactor temperature was adjusted to 45 °C and maintained at this temperature throughout the process. The solution was then infused with water at a flow rate of 0.3 m... 3 A flow rate of N2 gas is fed at a rate of / h to ensure an inert atmosphere inside the reaction vessel.

[0047] Next, a 130 g / L metal sulfate solution containing Ni and Mn (stoichiometric molar ratio of Ni:Mn 35:65), a 55 g / L ammonia solution, and a 220 g / L NaOH solution were continuously added at feed rates of 1.7 L / h, 0.046 L / h, and 1.44 L / h, respectively. The reaction mixture was stirred at 1200 rpm. The NH3(aq) concentration in the reaction mixture was maintained between 1.2 and 1.5 g / L by adjusting the feed rates of the ammonia solution and NaOH solution, and the pH of the reaction mixture was maintained between 12.1 and 12.25. The reaction was carried out in continuous mode. When the reaction reached a steady state, the reaction product, namely Ni particles with a D50 of 1.3 μm, was collected from the overflow of the reaction vessel. 0.35 Mn 0.65 (OH)2 water-based slurry.

[0048] (1b) Particle growth process First, the starting solution was prepared as follows: 3.6 L of DI water was placed in an 8.75 L reaction vessel equipped with two A45 impellers, with the lower impeller located 65 mm from the bottom of the vessel and the upper impeller located 140 mm above the lower impeller. After starting to feed N2 and O2 gases into the reaction vessel to maintain the O2 content in the reaction vessel atmosphere at 0.75 vol%, 400 ml of the prepared Ni particles with a D50 of 1.3 μm were added. 0.35 Mn 0.65 (OH)₂ seed pulp (48 g of seeds) was mixed with DI water. The pH of the initial solution was adjusted to 9.6 with 220 g / L NaOH(aq) (measured at 20 °C), and the reaction vessel was heated to 45 °C. Next, crystallization of the particles from the starting solution continued via a precipitation reaction as follows: 120 g / L of a metal sulfate solution containing Ni and Mn (stoichiometric molar ratio, Ni:Mn = 35:65) was added at a constant rate of 960 mL / h, and 220 g / L NaOH(aq) solution was added in such a manner that the pH of the reaction mixture in the reaction vessel increased from the pH of the starting solution and remained between a maximum of 10.8 and a minimum of 10.7 (measured at 20 °C). The reaction mixture was stirred at 1200 rpm for the first 2 hours, then at 800 rpm for the next 2 hours, at 600 rpm for the next 14 hours, and then at 500 rpm for the remaining precipitation. During the growth process, a portion of the liquid fraction of the reaction mixture (i.e., the mother liquor) was pumped out of the reaction vessel using a concentrator (i.e., a mother liquor filtration device) to maintain and increase the solid content in the reaction vessel. The reaction was terminated 50 hours after initiation.

[0049] The obtained slurry was filtered and washed with 220 g / L NaOH(aq) solution and DI water at 60 °C, then heat-treated in air at 120 °C and dried for 12 hours to obtain a hydroxyl oxide powder represented by the following general formula: Ni 0.35 Mn 0.65 -O a (OH)2- a , where 0≤a≤2, is the precursor of the cathode active material.

[0050] The physicochemical analysis of the obtained cathode active material precursor was performed as described above, including measurements of surface area, tap density, total particle size distribution, metal content, Na and S impurity levels, and total pore volume, and the results are listed in Table 1. Figure 1 A shows the surface and Figure 1 Figures B show the cross-sectional structures of the obtained hydroxyl oxides. The porous structure associated with the high BET value is clearly visible in these figures.

[0051] (2) Preparation steps of cathode active materials The obtained cathode active material precursor powder and lithium hydroxide powder were weighed such that the ratio of Li moles (mol) to total Me moles (mol) of transition metals (Ni and Mn) was 1.35 (Li / Me). The mixture was then stirred in a container mixer at 1000 rpm for 30 minutes. The mixture was then slowly heated in a furnace in an oxygen stream of 20 L / min to T. max The sample was sintered at 850 °C for 8 hours. After cooling, the sample was sieved to obtain a powder of the cathode active material.

[0052] Similarly, three other cathode active materials were prepared, differing in that T was modified in the following ways. max T respectively max =875°C, T max =905 °C and T max =925 °C. The physicochemical properties of the four cathode active materials obtained are reported in Table 2.

[0053] (3) Battery manufacturing and evaluation steps Lithium-ion batteries were fabricated using each of the four prepared cathode active materials. The cathode was prepared as follows: a uniform cathode active material powder containing a formulation of 92.2:3.3:4.5 by weight in a solvent (NMP, Mitsubishi), a conductor (Li-435, Denka) containing a dispersant (NBR), and a binder (KF#9700, Kureha) was prepared using a high-speed homogenizer to form a cathode slurry. The slurry was then applied to an aluminum foil using a doctor blade coater with a 180 μm gap. The slurry-coated foil was then dried in an oven at 120 °C and then pressed using a calender. It was then dried again in a vacuum oven to completely remove any remaining solvent from the electrode film to prepare the cathode.

[0054] The prepared cathode was then placed in an argon-filled glove box and assembled into a button cell housing together with a separator (Celgard 2320) located between the cathode and the lithium foil anode. The button cell was then completely sealed to prevent electrolyte leakage. The lithium foil anode had a thickness of 500 μm, and the separator (Tonen 20MMS polyethylene membrane) was used. The button cell was filled with a solution of LiPF6 dissolved in a mixed solvent of EC / EMC + LiBF4 + FEC to fabricate a lithium secondary battery.

[0055] The manufactured secondary batteries were tested according to the schedule shown in Table 2. Each battery was cycled using a Toscat-3100 computer-controlled constant current cycling station (from Toyo). A 1C current of 200 mA / g was defined in the scheme.

[0056] The discharge capacity DQ3 and efficiency (%) Ef of the third cycle are reported in Table 3. Ef is obtained from the following equation: , Where CQ1 is the charging capacity during the first cycle, and DQ1 is the discharging capacity during the first cycle.

[0057] Table 2. Cyclic Scheme for Button Battery Testing

[0058] Example 2 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and analyzed according to the same procedure as described in Example 1, except that during particle growth, the initial solution pH was 10.0, which was then increased and maintained between a maximum value of 10.9 and a minimum value of 10.7 during the precipitation reaction. Also, in the cathode active material preparation step, the pH was adjusted at two different T... max Two different types of cathode active materials were prepared by using cathode active material precursor powder and lithium hydroxide powder obtained by sintering at (850 °C and 925 °C). The batteries were prepared from these two cathode active materials and tested as described above.

[0059] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 1 C shows the surface and Figure 1 Table D shows the cross-sectional structures of the obtained cathode active material precursors. The physicochemical properties of the two obtained cathode active materials and the DQ and Ef of the two batteries fabricated are reported in Table 2.

[0060] Example 3 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and analyzed according to the same procedure as described in Example 1, except that during particle growth, the initial solution pH was 9.8, which was then increased and maintained between a maximum of 11.0 and a minimum of 10.7 during the precipitation reaction. Also, in the cathode active material preparation step, the pH was adjusted at two different T... max Two different types of cathode active materials were prepared by using cathode active material precursor powder and lithium hydroxide powder obtained by sintering at (850 °C and 925 °C). The batteries were prepared from these two cathode active materials and tested as described above.

[0061] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 1 E shows the surface and Figure 1 F shows the cross-sectional structures of the obtained cathode active material precursors. The physicochemical properties of the two obtained cathode active materials and the DQ and Ef of the two batteries fabricated are reported in Table 2.

[0062] Example 4 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and tested according to the same procedure as described in Example 1. The differences were that, in the seed slurry preparation process, the metal sulfate solution used contained only nickel sulfate (i.e., NiSO4), and the NH3(aq) concentration in the reaction mixture was maintained between 2.1-3.7 g / L and the pH of the reaction mixture was maintained between 12.4-12.7 by adjusting the feed of ammonia solution and NaOH solution, respectively. The differences were also that, during particle growth, 350 mL of the prepared Ni(OH)2 particle seed slurry with a D50 of 1.5 μm (46 g of seed) was mixed instead of the seeds used in Examples 1-3; the initial solution pH was 10.6, then increased and maintained between a maximum of 10.9 and a minimum of 10.7 during the precipitation reaction, and the reaction was terminated 24 hours after initiation. Finally, the differences were made in the cathode active material preparation step, by using two different T... max Two different types of cathode active materials were prepared by using cathode active material precursor powder and lithium hydroxide powder obtained by sintering at (850 °C and 925 °C). The batteries were prepared from these two cathode active materials and tested as described above.

[0063] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 1 G shows the surface and Figure 1 H shows the cross-sectional structures of the obtained cathode active material precursors. The physicochemical properties of the two obtained cathode active materials and the DQ and Ef of the two batteries fabricated are reported in Table 2.

[0064] Comparative Example 1 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and tested according to the same procedure as described in Example 1, except that during particle growth, N2 and O2 gases were fed into the reaction vessel to maintain the O2 content in the reaction vessel atmosphere at 1.55% by volume. The initial solution pH was 11.1, and then maintained between a maximum value of 11.0 and a minimum value of 10.9 during the precipitation reaction. The reaction mixture was stirred at 1200 rpm for the first 2 hours, then at 800 rpm for the next 2 hours, and then at 600 rpm for the remaining precipitation process. The reaction was terminated after 38 hours. The sintering temperature T was varied. max Four different cathode active materials were prepared, and then four different batteries were prepared and tested in the same manner as in Example 1.

[0065] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 2A shows the surface and Figure 2 B shows the cross-sectional structures of the obtained cathode active material precursors. The physicochemical properties of the four obtained cathode active materials and the DQ and Ef of the four batteries fabricated are reported in Table 2.

[0066] Comparative Example 2 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and tested according to the same procedure as described in Example 1. The difference was that during the particle growth process, 3.25 L of DI water and 250 mL of the prepared Ni particles with a D50 of 1.3 μm were added. 0.35 Mn 0.65 (OH)₂ seed slurry (30 g) was added to a reaction vessel equipped with a turbine impeller located 46 mm from the bottom. N₂ gas was fed into the reaction vessel, but no O₂ gas was fed to maintain an inert atmosphere. The initial solution pH was 10.4, which was then maintained between a maximum of 11.1 and a minimum of 10.9 during the precipitation reaction. The reaction mixture was stirred at 850 rpm for the first 2 hours, then at 700 rpm for the next 2 hours, and then at 600 rpm for the remaining precipitation. The reaction was terminated after 22 hours. The sintering temperature T was varied. max Four different cathode active materials were prepared in the same manner as in Example 1.

[0067] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 2 Figure C shows the surface and 2D diagrams, respectively, illustrating the cross-sectional structures of the obtained cathode active material precursors. The physicochemical properties of the four obtained cathode active materials, as well as the DQ and Ef of the four cells fabricated, are reported in Table 2.

[0068] Comparative Example 3 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and tested according to the same procedure as described in Example 1, except that during particle growth, 2.7 L of DI water and 800 mL of the prepared Ni particles with a D50 of 1.5 µm were mixed. 0.35 Mn 0.65(OH)₂ seed slurry (96 g seed amount) was added to a reaction vessel equipped with a turbine impeller located 65 mm from the bottom. N₂ gas was fed into the reaction vessel, but no O₂ gas was fed to maintain an inert atmosphere. The metal sulfate solution was fed at a rate of 1200 mL / h. The initial solution pH was 11.0, which was then maintained between a maximum of 11.1 and a minimum of 10.6 during the precipitation reaction. The reaction mixture was stirred at 1000 rpm for the first 2 hours, and then at 800 rpm for the remainder of the precipitation process. The reaction was terminated after 46 hours. The sintering temperature T was varied. max Four different cathode active materials were prepared in the same manner as in Example 1.

[0069] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 2 E shows the surface, and 2F shows the cross-sectional structure of the obtained cathode active material precursors, respectively. The physicochemical properties of the four obtained cathode active materials and the DQ and Ef of the four cells fabricated are reported in Table 2.

[0070] Comparative Example 4 The cathode active material precursor, cathode active material, and lithium secondary battery were prepared and tested according to the same procedure as described in Example 1, except that a 200 L reaction vessel equipped with a turbine impeller was used during particle growth. The starting solution was prepared by adding 100 L of water and 15 L of seed slurry (1.8 kg) of Ni(OH)₂ particles with a D50 of 1.5 μm prepared in Example 4, and adjusting the pH to 10.4. During the precipitation reaction, a metal sulfate solution was fed at a constant rate of 25 L / h. The pH of the reaction mixture in the reaction vessel was increased from the pH of the starting solution and maintained between a maximum of 10.9 and a minimum of 10.7 (measured at 20 °C). N₂ and O₂ gases were fed into the reaction vessel to maintain an O₂ content of 4.2 vol% in the atmosphere. The reaction mixture was stirred at 550 rpm for the first 2 hours, and then at 400 rpm for the next 2 hours. The mixture was stirred at rpm, then at 300 rpm for the next 18 hours, followed by stirring at 200 rpm for the remaining precipitation process, and the reaction was terminated after 38 hours. In the cathode active material preparation step, the mixture was stirred at two different T... maxTwo different types of cathode active materials were prepared by using cathode active material precursor powder and lithium hydroxide powder obtained by sintering at (850 °C and 925 °C). The batteries were prepared from these two cathode active materials and tested in the same manner as described in Example 1.

[0071] Table 1 lists the physicochemical properties of the cathode active material precursors obtained in this embodiment. Figure 2 G shows the surface and 2H show the cross-sectional structures of the obtained cathode active material precursors, respectively. The physicochemical properties of the four obtained cathode active materials and the DQ and Ef of the four batteries fabricated are reported in Table 2.

[0072] Discussion of Results Referring to Tables 1 and 2, compared with the lithium secondary battery of the comparative example, the lithium secondary battery of the embodiment has an overall improved discharge capacity (DQ3) and capacity efficiency (Ef).

[0073] In Comparative Example 1, since the precursor's TD value was lower than that of Examples 1-4, the battery's DQ3 and Ef were potentially significantly reduced, in addition to its higher TPV value.

[0074] In Comparative Examples 2 and 3, the DQ3 and Ef of their batteries were significantly reduced because their precursors had low SSA values ​​and therefore low SSA / TD values.

[0075] In Comparative Example 4, since the precursor's TD value is higher than the corresponding values ​​in Examples 1-4, the battery's DQ3 and Ef are potentially significantly reduced even though its TPV value is relatively high.

[0076] Referring to the sintering temperature used, compared with Comparative Examples 1-4, the best battery performance for DQ3 and Ef was obtained in Examples 1-4 using the lowest test sintering temperature of 850 °C. Table 1

[0077]

[0078]

Claims

1. A manganese-containing precursor for a cathode active material in a secondary battery, the precursor comprising M and elemental oxygen, wherein M comprises: - Ni with a content of x relative to M, where 0.0 ≤ x ≤ 50.0 mol%. - Mn with a content of y relative to M, where 50.0 ≤ y ≤ 90.0 mol%. - Co with a content of z relative to M, where 0.0 ≤ z ≤ 40.0 mol%. - Relative to M, at least one element selected from the group consisting of Al, Ti, V, Mg, Cr, Ca, Zr, Nb, Mo, Hf, Ta, and W, with a content of t, 0.0 ≤ t ≤ 10.0 mol% - Where x, y, z, and t are measured by ICP-OES; and - where x+y+z+t is 100.0 mol%; and in The manganese-containing precursor has a content of at least 1.65 g / cm³. 3 The tapped density TD and a specific surface area SSA of at least 12.00, as measured by the BET method, to the tapped density, SSA / TD, the ratio being expressed in units (m²). 2 cm 3 ) / g 2 Indicate; and The precursor is composed of the general formula MO a (OH) 2-a This indicates that 0 ≤ a ≤ 2.

2. The manganese-containing precursor according to claim 1, wherein the ratio SSA / TD is at least 14.

00.

3. The manganese-containing precursor according to any one of the preceding claims, wherein the ratio SSA / TD is at most 30.00, preferably at most 25.

00.

4. The manganese-containing precursor according to any one of the preceding claims, wherein the manganese-containing precursor has a minimum of 0.100 cm⁻¹ determined by nitrogen adsorption measurement and calculated according to BJH. 3 / g total pore volume (TPV); preferably, the TPV is at most 0.200 cm³. 3 / g, more preferably up to 0.180 cm 3 / g.

5. The manganese-containing precursor according to any one of the preceding claims, wherein the Ni content x is at most 45 mol% and preferably at least 10 mol%, more preferably at least 15 mol%.

6. The manganese-containing precursor according to any one of the preceding claims, wherein the tap density is at least 1.70 g / cm³. 3 .

7. The manganese-containing precursor according to any one of the preceding claims, wherein the tap density is at most 2.00 g / cm³. 3 Preferably, the tap density is at most 1.90 g / cm³. 3 The most preferred value is at most 1.80 g / cm³. 3 .

8. The manganese-containing precursor according to any one of the preceding claims, wherein the specific surface area is at least 25.00 m². 2 / g, preferably at least 30.00 m 2 / g, more preferably at least 33.00 m 2 / g.

9. The manganese-containing precursor according to any one of the preceding claims, wherein the manganese-containing precursor has a median particle size D50 of at least 5.00 µm as determined by laser diffraction; preferably, the D50 is at most 12.00 µm, more preferably at most 10.00 µm.

10. The manganese-containing precursor according to any one of the preceding claims, wherein - The Mn content y is at least 55 mol% or at least 60 mol%, and / or - The Mn content y is at most 80 mol% or at most 70 mol%.

11. The manganese-containing precursor according to any one of the preceding claims, wherein the manganese-containing precursor has a Na content of up to 100 ppm.

12. The manganese-containing precursor according to any one of the preceding claims, wherein the manganese-containing precursor has an S content of up to 5000 ppm, preferably wherein the S content is at least 1400 ppm.

13. The manganese-containing precursor according to any one of the preceding claims, said manganese-containing precursor comprising secondary particles composed of aggregated primary particles, wherein said primary particles have a particle-based thickness distribution as determined by measuring the thickness of the primary particles in an image taken by SEM, wherein When the cumulative percentage reaches 75%, the thickness distribution has a corresponding thickness between 10 nm and 70 nm, preferably between 20 nm and 50 nm; and / or When the cumulative percentage reaches 50%, the thickness distribution has a corresponding thickness between 10 nm and 70 nm, preferably between 20 nm and 40 nm.

14. A cathode active material for a lithium-ion secondary battery, said cathode active material comprising lithium-transition metal composite oxide particles formed by using a manganese-containing precursor according to any one of claims 1 to 13.

15. A lithium-ion secondary battery, the lithium-ion secondary battery comprising: The cathode includes a cathode active material layer comprising the cathode active material according to claim 14.

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