Manufacturing method of electrode active material

Abstract

1. A method for producing an electrode active material, the method comprising the steps of: (a) mixing a composite oxide, composite (oxy)hydroxide, composite hydroxide or composite carbonate of nickel, at least one of cobalt and manganese, and optionally at least one of Mg, Al and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo and W, with at least one lithium source selected from lithium carbonate, lithium oxide and lithium hydroxide, and optionally at least one dopant selected from oxides, hydroxides and oxyhydroxides of Mg, Al, Y, Ti, Zr, Nb, Ta, Fe, Mo and W, and fluorides; (b) optionally transferring the mixture into a sagger, crucible or open cup; (c) firing the mixture in a pusher kiln, a roller hearth kiln, or a rotary kiln at a temperature in the range of 700°C to 1000°C; (d) cooling the obtained electrode active material; (e) applying a robot to take at least two samples to be analyzed, each of 10 mg to 10 g, per sagger, crucible or open cup, or per defined period of time; (f) transferring the sample to another robot or to another part of the same robot, each robot producing an electrode material mixture from the same sagger, crucible or open cup sample; (g) transferring the electrode material mixture to a test unit for electrochemical testing; Including, The robot performs steps (f) to (g) on ​​multiple samples in parallel.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an electrode active material, wherein the method comprises the following steps: (a) mixing a composite oxide, composite (oxy)hydroxide, composite hydroxide or composite carbonate of nickel, at least one of cobalt and manganese, and optionally at least one of Mg, Al and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo and W, with at least one lithium source selected from lithium carbonate, lithium oxide and lithium hydroxide, and optionally at least one dopant selected from oxides, hydroxides and oxyhydroxides of Mg, Al, Y, Ti, Zr, Nb, Ta, Fe, Mo and W, and fluorides; (b) optionally transferring the mixture into a sagger, crucible or open cup; (c) firing the mixture in a pusher kiln, a roller hearth kiln, or a rotary kiln at a temperature in the range of 700°C to 1000°C; (d) cooling the obtained electrode active material; (e) applying a robot to take at least two samples to be analyzed, each of 10 mg to 10 g, for each individual sagger, crucible or open cup, or for each defined period of time; (f) transferring the sample to another robot or to another part of the same robot, which robot produces an electrode material mixture from the sample in the same sagger, crucible, or open cup; (g) transferring the electrode material mixture to a test unit for electrochemical testing; Including, The robot performs steps (f) to (g) on ​​multiple samples in parallel. [Background technology]

[0002] Lithium-ion secondary batteries are state-of-the-art devices for energy storage. Many applications have been considered, ranging from small devices such as mobile phones and laptop computers to car batteries and other e-mobility batteries. Various battery components, such as electrolytes, electrode materials, and separators, play important roles in battery performance. Cathode materials have received particular attention. Several materials have been proposed, such as lithium iron phosphate, lithium cobalt oxide, and lithium nickel cobalt manganese oxide. Although extensive research has been conducted, solutions found to date still require improvement.

[0003] Cathode active materials are generally prepared using a two-step process. In the first step, a sparingly soluble compound of the transition metal(s) is prepared by precipitating it from a solution, such as a carbonate or hydroxide. The sparingly soluble salt is often also referred to as a precursor. In the second step, the precursor is mixed with a lithium compound, such as Li2CO3, LiOH, or Li2O, and calcined at high temperatures, such as 600-1100°C.

[0004] Some technical issues remain unresolved. Volumetric energy density, capacity fade, and cycle stability remain areas of research and development. However, further problems have been identified in production. While consistent product quality is desirable, sometimes the quality and composition can vary widely. However, high quality variations can lead to a high number of products that do not meet specifications (hereafter referred to as "off-spec" material), which can increase costs. Summary of the Invention [Problem to be solved by the invention]

[0005] It was therefore an object of the present invention to provide a method that results in more uniform product quality and a reduced amount of off-spec material in the manufacture of electrode active materials. [Means for solving the problem]

[0006] Thus, a method as defined at the beginning, hereinafter also referred to as "the method of the invention" or "the method according to the invention", has been found. The method of the invention comprises a series of steps as defined at the beginning, hereinafter also defined as step (a), step (b), step (c), etc. The method of the invention is explained in more detail below. Step (b) is an optional step. DETAILED DESCRIPTION OF THE INVENTION

[0007] By carrying out the method of the present invention, an electrode active material is produced. The electrode active material has the general formula Li 1+x TM 1-x O2, where TM contains nickel, at least one of cobalt and manganese, and optionally at least one of Mg, Al, and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo, and W. In embodiments in which TM is predominantly manganese, x is preferably in the range of 0 to 0.3. In embodiments in which the molar amount of nickel is at least equal to or greater than the molar amount of manganese, x is preferably in the range of −0.02 to 0.15.

[0008] Step (a) involves mixing a precursor selected from a composite oxide, composite (oxy)hydroxide, composite hydroxide, and composite carbonate of nickel, at least one of cobalt and manganese, and optionally at least one of Mg, Al, and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo, and W, with at least one lithium source selected from lithium carbonate, lithium oxide, and lithium hydroxide, and optionally at least one dopant selected from oxides, hydroxides, and oxyhydroxides of Mg, Al, Y, Ti, Zr, Nb, Ta, Fe, Mo, and W, and from fluorides. The term lithium hydroxide includes LiOH and hydrates of LiOH, such as LiOH·HO. The stoichiometry of the precursor and lithium source is selected depending on the desired electrode active material.

[0009] The precursor is preferably obtained by co-precipitation of nickel, cobalt, and manganese as hydroxides from an aqueous solution containing the nitrates, acetates, or preferably sulfates of nickel, cobalt, and manganese in the stoichiometric ratios corresponding to TM. The co-precipitation is achieved by the addition of an alkali metal hydroxide, e.g., potassium hydroxide or sodium hydroxide, in a continuous, semi-continuous, or batch process. The co-precipitation is then followed by removal of the mother liquor, e.g., by filtration, followed by removal of the water.

[0010] The precursor is particulate. In one embodiment of the present invention, the mean particle size (D50) of such precursor is in the range of 4 to 16 μm, preferably 7 to 10 μm. Mean particle size (D50) in the context of the present invention means the median particle size based on volume, as can be determined, for example, by light scattering. In one embodiment, the precursor has a unimodal particle size distribution. In other embodiments, the particle distribution of the precursor may be bimodal, for example, with one maximum in the range of 1 to 5 μm and a further maximum in the range of 7 to 16 μm.

[0011] The particle shape of the secondary particles of the precursor is preferably spherical, which means particles having a spherical shape. Spherical spheres include not only particles that are exactly spherical, but also particles in which the difference between the maximum and minimum diameters of at least 90% (number average) of a representative sample is 10% or less.

[0012] In one embodiment of the present invention, the precursor is composed of secondary particles that are agglomerates of primary particles. Preferably, the precursor is composed of spherical secondary particles that are agglomerates of primary particles. Even more preferably, the precursor is composed of spherical secondary particles that are agglomerates of spherical primary particles or platelets.

[0013] In one embodiment of the present invention, the precursor may have a particle size distribution span in the range of 0.5 to 0.9, where the span is defined as [(D90) - (D10)] divided by (D50), all determined by LASER analysis. In another embodiment of the present invention, the precursor may have a particle size distribution span in the range of 1.1 to 1.8.

[0014] In one embodiment of the present invention, the specific surface area (BET) of the precursor is between 2 and 10 m, determined by nitrogen adsorption, for example according to DIN-ISO 9277:2003-05. 2 / g, or even 15 to 100 m 2 / g range.

[0015] In one embodiment of the present invention, the precursor may have a uniform distribution of the transition metals nickel, cobalt, and manganese across the diameter of the particle. In another embodiment of the present invention, the distribution of at least two of the nickel, cobalt, and manganese is not uniform, but rather exhibits, for example, a gradient of nickel and manganese, or exhibits layers of different concentrations of at least two of the nickel, cobalt, and manganese. Preferably, the precursor has a uniform distribution of the transition metal across the diameter of the particle.

[0016] In one embodiment of the present invention, the precursor may contain elements other than nickel and at least one of cobalt and manganese, such as at least one of Mg, Al and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo and W, for example in an amount of 0.1 to 5 mol % relative to TM. However, it is preferred that the precursor contains elements other than nickel, cobalt and manganese only in negligible amounts, for example at a detectable level of up to 0.05 mol %.

[0017] The precursor may contain trace amounts of metal ions, e.g., trace amounts of ubiquitous metals such as sodium, calcium, iron, or zinc, as impurities, but such trace amounts are not considered within the context of the present invention. Trace amounts in this context shall mean amounts of 0.05 mol % or less, relative to the total metal content of the TM.

[0018] In one embodiment of the present invention, the precursor contains one or more impurities such as residual sulfates when prepared by co-precipitation from a solution of one or more sulfates of nickel, cobalt, and manganese, and the sulfates may be in the range of 0.1 to 0.4% by mass based on the total precursor.

[0019] In one embodiment of the invention, the precursor is an oxide, oxyhydroxide or hydroxide of TM, wherein TM is of general formula (I): (Ni a Co b Mn c ) 1-d M d (I) (wherein a is in the range of 0.6 to 0.90, preferably 0.6 to 0.7, b is in the range of 0.05 to 0.2, preferably 0.1 to 0.2, c is in the range of 0.05 to 0.2, preferably 0.1 to 0.2, d is in the range of 0 to 0.1, preferably 0.005 to 0.1, M is Al, Ti, Zr, or a combination of at least two of the foregoing; a+b+c=1).

[0020] Optionally, at least one dopant selected from oxides, hydroxides and oxyhydroxides of Mg, Al, Y, Ti, Zr, Nb, Ta, Fe, Mo and W may be added to the precursor and to the lithium source.

[0021] The mixing of the precursor, lithium source, and optionally the dopant(s) may be carried out all in one step or in multiple substeps, for example by first mixing the lithium source and dopant and adding the resulting mixture to the precursor, or by first mixing the precursor and lithium source and optionally subsequently adding the dopant, or by first mixing the dopant(s) and precursor and subsequently adding the lithium source. It is preferred to mix the precursor and lithium source first and subsequently add the dopant(s).

[0022] In step (a), a mixture is obtained.

[0023] In optional step (b), the mixture obtained from step (a) is transferred into a sagger, crucible, or open cup. The loading of the sagger, crucible, or open cup can be selected within a wide range, for example, from 4 to 15 kg. Preferably, the loading ranges from. In embodiments where step (c) is carried out in a rotary kiln, step (b) is eliminated.

[0024] Step (c) comprises calcining the mixture in a pusher kiln, roller hearth kiln or rotary kiln at a temperature in the range of 700°C to 1000°C.

[0025] In one embodiment of the invention, a mixture of precursor, lithium source and optionally dopant(s) is heated to 700-1000° C. at a heating rate of 0.1-10 K / min.

[0026] In one embodiment of the present invention, the temperature in step (c) is increased before reaching the desired temperature of 700-1000° C., preferably 750-900° C. For example, the mixture of precursor, lithium source, and optionally dopant(s) is first heated to 350-550° C., then held constant for a period of 10 minutes to 4 hours, and then increased to 700-1000° C.

[0027] In one embodiment of the present invention, step (c) is carried out in a roller hearth kiln, a pusher kiln, or a rotary kiln, or a combination of at least two of them. A rotary kiln has the advantage that the material produced therein is very homogenized. In roller hearth kilns and pusher kilns, different reaction conditions for different steps can be set very easily.

[0028] In one embodiment of the present invention, step (c) is carried out in an oxygen-containing atmosphere, such as a nitrogen-air mixture, a noble gas-oxygen mixture, air, oxygen, or oxygen-enriched air. In a preferred embodiment, the atmosphere in step (c) is selected from air, oxygen, and oxygen-enriched air. The oxygen-enriched air may be, for example, a 50:50 volume ratio mixture of air and oxygen. Other options include a 1:2 volume ratio mixture of air and oxygen, a 1:3 volume ratio mixture of air and oxygen, a 2:1 volume ratio mixture of air and oxygen, and a 3:1 volume ratio mixture of air and oxygen.

[0029] In one embodiment of the present invention, step (c) of the present invention is carried out under a flow of gas, such as air, oxygen, and oxygen-enriched air. Such a gas flow may be referred to as a forced gas flow. Such a gas flow is represented by the general formula Li 1+x TM 1-x O2 per kg of material, 0.5-15 m 3 The gas flow can have a specific flow rate in the range of 1 / h. The volume is determined under normal conditions (298 Kelvin and 1 atmosphere). The gas flow is useful for removing gaseous decomposition products such as water and carbon dioxide.

[0030] The method of the present invention may include a further step following step (c), such as, but not limited to, a further calcination step at a temperature in the range of 500-1000°C.

[0031] In one embodiment of the present invention, step (c) has a duration ranging from 1 hour to 30 hours, preferably from 5 hours to 12 hours.

[0032] Preferably, the electrode active material obtained from step (c) has a surface area of ​​0.1 to 0.8 m 2 / g, determined according to DIN-ISO 9277:2003-05.

[0033] After calcination according to step (c), the thus obtained electrode active material is cooled before further processing, step (d), which may be carried out by exposing the freshly prepared electrode active material to room temperature. In embodiments in which step (c) is carried out in a rotary hearth kiln or a pusher kiln, the freshly prepared electrode active material is left in its respective sagger, crucible, or open cup during step (d).

[0034] In one embodiment of the present invention, the average cooling rate is in the range of 1 to 3 K / min.

[0035] In one embodiment of the present invention, step (d) is carried out at a maximum temperature of up to 150°C, preferably up to 120°C, with a temperature range of 60-120°C being more preferred. The maximum temperature refers to the temperature of the freshly produced electrode active material measured after the saggers leave the kiln. Higher temperatures may damage the robots employed in the subsequent step (e).

[0036] In an optional step, after step (d), the freshly produced electrode active material may be deagglomerated, for example, in a mill, such as an air classifier mill. In laboratory-scale experiments, a sieving stack is also feasible.

[0037] A robot is employed to carry out step (e). The robot takes at least two samples of 10 mg to 10 g, preferably 20 mg to 5 g, and more preferably 100 mg to 2 g, per sagger, crucible, or open cup to be analyzed or per defined period. The samples are taken from different positions on each sagger, crucible, or open cup to ensure that material from the inside of the charge as well as material from the surface of the sagger, crucible, or open cup is analyzed. In embodiments where a rotary kiln is used in step (c), such samples are taken at defined periods, for example, every 2 hours or every 5 hours.

[0038] In one embodiment of the present invention, the robot takes 2 to 10 samples, preferably 3 to 5, per sagger, crucible, or open cup to be analyzed or per defined period. The more samples taken, the more assured that the samples provide a representative average of the entire load. However, taking too many samples will result in too much electrode material being used for analysis.

[0039] In a preferred embodiment, samples taken from the same sagger, crucible or open cup are combined and intimately mixed by a robot before further analysis.

[0040] While it is possible to have the robot take a sample from each sagger, crucible, or open cup, it is preferred not to analyze every sagger, crucible, or open cup. For example, in many embodiments, it is sufficient to have the robot take a sample from one of every 5 to 12 saggers, crucibles, or open cups per production run. This number of samples is generally sufficient, particularly when tracking specific trends in synthesis performance. In other embodiments, such as those in which step (c) is performed in a rotary kiln, it is preferred to have the robot take samples after a set period of time, for example, every 20 minutes to every 12 hours, preferably every 30 minutes to every 6 hours.

[0041] The robot can assign a number to the combined sample taken from each sagger, crucible or open cup to be analyzed and combine that number with the respective sagger, crucible or open cup number to enable tracking of samples by sagger, crucible or open cup.

[0042] In other embodiments, the saggers, crucibles or open cups are not numbered, and merely the trend of the results of step (f) or (g) is determined. If the trend indicates that the sample does not meet specifications, the robot responds (acts) as follows:

[0043] The robot can collect the sample with a robotic arm that holds a device such as a spatula, spoon-like instrument, or the like for collecting the sample.

[0044] In step (f), the robot transfers the sample to another robot or to another part of itself, where each robot makes an electrode material mixture from the same sagger, crucible or open cup of electrode material sample. In the context of the present invention, unless otherwise specified, no distinction is made between a "different part" of the same robot taking a sample from the same sagger, crucible or open cup and a second, and therefore different, robot performing the analysis.

[0045] The electrode material mixture is preferably similar to the electrode material mixture used to manufacture commercially available electrodes. Commercially available electrode material mixtures typically contain an electrode active material, conductive carbon, and a binder polymer slurried in water or an aprotic organic solvent. A preferred aprotic organic solvent is N-methylpyrrolidone ("NMP").

[0046] Suitable binder polymers are preferably selected from organic (co)polymers, preferably those without ionic groups. Suitable organic (co)polymers, i.e., homopolymers or copolymers, can be selected, for example, from (co)polymers obtainable by anionic (co)polymerization, catalytic (co)polymerization, or free-radical (co)polymerization, in particular from polyethylene, polyacrylonitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth)acrylonitrile, and 1,3-butadiene. Polypropylene is also suitable. Polyisoprene and polyacrylates are further suitable. Polyacrylonitrile is particularly preferred.

[0047] In the context of the present invention, polyacrylonitrile is understood to mean not only polyacrylonitrile homopolymers but also copolymers of acrylonitrile with 1,3-butadiene or styrene, with polyacrylonitrile homopolymers being preferred.

[0048] In the context of the present invention, polyethylene refers not only to homopolyethylenes but also to copolymerized ethylene at least 50 mol % and up to 50 mol % of at least one further comonomer, such as α-olefins, for example propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, and also isobutene, vinyl aromatics, for example styrene, and also (meth)acrylic acid, vinyl acetate, vinyl propionate, C1-C2 copolymers of (meth)acrylic acid. 10 -Alkyl esters, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and also copolymers of ethylene with maleic acid, maleic anhydride and itaconic anhydride. Polyethylene can be HDPE or LDPE.

[0049] In the context of the present invention, polypropylene is understood to mean not only homopolypropylene but also copolymers of propylene with at least 50 mol % copolymerized propylene and up to 50 mol % of at least one further comonomer, such as ethylene, and α-olefins, such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-pentene. The polypropylene is preferably isotactic or essentially isotactic polypropylene.

[0050] In the context of the present invention, polystyrene is not only a homopolymer of styrene, but also a C1-C6 copolymer of acrylonitrile, 1,3-butadiene, (meth)acrylic acid, 10 -alkyl esters, divinylbenzene, in particular 1,3-divinylbenzene, copolymers with 1,2-diphenylethylene and α-methylstyrene are also understood to mean.

[0051] Another preferred binder is polybutadiene.

[0052] Other suitable binders are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

[0053] In one embodiment of the present invention, the binder has an average molecular weight M ranging from 50,000 g / mol to 1,000,000 g / mol, preferably up to 500,000 g / mol. W The (co)polymers are selected from the group consisting of:

[0054] The binder may be a crosslinked or non-crosslinked (co)polymer.

[0055] In a particularly preferred embodiment of the present invention, the binder polymer is selected from halogenated (co)polymers, in particular fluorinated (co)polymers.Halogenated or fluorinated (co)polymers are understood to mean (co)polymers that contain at least one (co)polymerized (co)monomer having at least one halogen atom or at least one fluorine atom per molecule, more preferably at least two halogen atoms or at least two fluorine atoms per molecule.Examples include polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymer, perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, and ethylene-chlorofluoroethylene copolymer.

[0056] Suitable binder polymers are especially polyvinyl alcohol and halogenated (co)polymers such as polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvinyl fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.

[0057] The conductive carbon may be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite.

[0058] Preferably, step (f) comprises mixing the electrode active material with conductive carbon, a binder polymer and NMP, and even more preferably with a binder polymer, NMP and a combination of graphite and a conductive carbon other than graphite, such as soot.

[0059] In one embodiment of the present invention, the amount used in step (f) is based on 10 mg to 10 g, preferably 100 mg to 2 g of electrode active material.

[0060] In one embodiment of the present invention, (A) 80 to 96 mass % of an electrode active material; (B) 2 to 18 mass% carbon; (C) 2 to 10% by mass of a binder polymer Includes:

[0061] In one embodiment of the present invention, up to 12 ml, for example 2 to 15 ml, of solvent is used per sample of electrode active material.

[0062] In one embodiment of the present invention, step (f) is carried out in a molding die having a large number of recesses arranged in an array, or in the wells of a microtiter plate, where "large number" in this context preferably ranges from 3 to 20, preferably from 5 to 12.

[0063] Step (f) provides an electrode material mixture, which is applied to a current collector, for example, in step (f) or step (g). The current collector is preferably made from aluminum, for example, aluminum foil, with dimensions compatible with the test unit used in step (g).

[0064] In one embodiment of the present invention, the electrode material mixture is applied to the current collector with the aid of an electronic pipette or an overhead weight distribution unit.

[0065] In one embodiment of the invention, the application comprises evaporating the solvent, in particular NMP, followed by pressing the raw electrode with a heated stamp or treating the raw electrode by calendering.

[0066] In one embodiment of the present invention, each electrode material mixture is applied to at least two current collectors, e.g., 2 to 5 current collectors, to determine the average value of the electrochemical test. In another embodiment, each electrode material mixture is applied to only one current collector.

[0067] In one embodiment of the present invention, an amount of 5 to 20 mg of electrode active material is applied to each electrode. In a coin-type cell, the average diameter may range from 5 to 20 mm.

[0068] Overall, the robot performs steps (f)-(g) on ​​multiple samples in parallel, e.g., 2-12 samples.

[0069] In step (g), each robot transfers the electrode material mixture, either as is or already applied to a current collector, to a test unit to perform electrochemical testing, obtaining in particular the first discharge in mA·h / g and the efficiency in %.

[0070] In one embodiment of the present invention, step (g) comprises the following substeps: (g1) disposing each electrode material mixture on a current collector; (g2) removing volatile materials from the electrode material mixture on the current collector, thereby obtaining a cathode; (g3) attaching the obtained cathode to a separator combined with an anode and an electrolyte, thereby obtaining a coin cell; (g4) performing an electrochemical test using the coin cell from substep (g3); The sub-steps are performed by a robot.

[0071] Alternatively, steps (g1) and (g2) may be carried out in conjunction with step (f).

[0072] In substep (g1), each electrode material mixture is placed on a current collector, as described above, followed by removing any volatiles from the electrode material mixture on the current collector in substep (g2), for example by evaporation or drying of the solvent in any substep.

[0073] Substep (g3) involves attaching the resulting cathode to a separator, each of which is combined with an anode and an electrolyte, thereby obtaining a coin cell. Examples of suitable anodes include graphite anodes and lithium metal anodes. In substep (g4), electrochemical tests are performed using the coin cell from (g3), preferably in an electrochemical testing unit. Suitable tests include capacity fade with repeated cycling and initial capacity tests.

[0074] The test unit preferably includes a counter anode, which is formed by mechanically separating the anode and cathode. Suitable separators are polymer films, particularly porous polymer films, and are therefore unreactive with metallic lithium. Particularly suitable materials for the separator are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0075] A separator made of polyolefin, particularly polyethylene or polypropylene, can have a porosity in the range of 35 to 45%. Suitable pore sizes are, for example, in the range of 30 to 500 nm.

[0076] Suitable electrolytes for lithium-ion batteries are known per se. Examples include solutions of lithium salts in aprotic organic solvents. The lithium salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, and LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred. Examples of suitable solvents are organic carbonates, with mixtures of diethyl carbonate and methyl ethyl carbonate and mixtures of at least one of the foregoing with at least one cyclic organic carbonate being preferred.

[0077] In one embodiment of the invention, the test unit comprises a plurality of coin-cell electrochemical cells, e.g., wells of a microtiter plate, arranged in an array, the coin-cell electrochemical cells being opened and closed by a robot, the opening and closing being controlled by software within the robot.

[0078] In one embodiment of the invention, upon opening of the robot, the previously tested electrodes are mechanically removed from the test unit and the newly formed electrodes are mechanically placed on the separator.

[0079] In one embodiment of the present invention, the entire description of steps (e)-(g) is performed by a computer, and the results of the electrochemical testing are compared to the desired result by the computer. In a preferred embodiment, the processing device collects data as input via an input channel, and then provides an electronic signal to a production control function via an output channel if at least two consecutive samples show a negative deviation from the desired result. In this context, a negative deviation can refer to a too low initial capacity, too high impedance buildup, too high capacity fade after repeated cycling, or too low initial discharge capacity, respectively, by a deviation of at least 1-5%. The production control function can be a computer that monitors the production process alone or with human assistance. With the help of the signal, the production control function can therefore adjust either step (b) or (c), for example, the temperature or time of the firing step (c).

[0080] For example, in optional step (h) performed in parallel with step (f), each robot may distribute the sample to at least one analytical device other than that used in step (g), such as X-ray diffraction ("XRD"), scanning electron microscope ("SEM"), titration with acid for residual base determination, or inductively coupled plasma-optical emission spectroscopy ("ICP-OES").

[0081] In one embodiment of the present invention, the entire description of step (h)(ies) is performed by a processor, and the results of the electrochemical test are compared to a desired result by the processor. In this context, "desired result" refers to a specified characteristic of the respective electrode active material, such as, but not limited to, initial capacity or efficiency. In a preferred embodiment, the processor sends an electronic signal to a production control function if at least two consecutive samples show a negative deviation from the desired result. In this context, a negative deviation, where applicable, of at least 1-5% of a specified value, preferably at least 1-2% in the case of electrochemical data, and further 5% or less in the case of BET surface area, can mean that the acid consumption is too high, and therefore the residual lithium content is too high, or that the deviation of any metal is too strong.

[0082] In optional step (i), a post-treatment may be performed after step (c) or before or after steps (e) to (g). Examples of optional step (i) include, but are not limited to, a coating process, such as the processes disclosed in WO 2019 / 154701 and WO 2019 / 154702, or a water treatment as described in EP 3 024 068, or coating with a fluoride. Examples of fluorides include LiF, NHF, and (NH)F HF.

[0083] By carrying out the method of the present invention, electrode active materials with excellent properties can be obtained through a simple and stable process, production runs can be efficiently monitored, the amount of off-spec material can be reduced, and tedious manual work and human exposure to nickel oxide-containing powder can be reduced.

[0084] A further aspect of the invention relates to an apparatus setup, hereinafter also referred to as the setup of the invention, comprising a robot having a device for taking a 10 mg to 10 g electrode active material sample, and means for transferring the sample to another robot or to another part of the same robot, which robot creates an electrode material mixture from the sample, and means for transferring the electrode material mixture to a testing unit for electrochemical testing. An example of a robot is a synthesis robot.

[0085] In a preferred embodiment of the present invention, the system of the present invention further comprises a processing device that carries out the recitation of steps (e)-(g) of the method of the present invention and compares the results of the electrochemical test with the desired results.

[0086] In a preferred embodiment of the present invention, the system of the present invention further comprises a processing unit that collects data as input via an input channel and provides an electronic signal via an output channel to a production control function if at least two consecutive samples show a negative deviation from a desired result, the term "desired result" being as defined above.

[0087] The following examples illustrate the invention. [Example]

[0088] I. Precursor Provision I.1 Synthesis of precursor TM-OH.1 Deionized water was placed in a stirred tank reactor, heated to 55° C. and adjusted to a pH value of 12 by adding aqueous sodium hydroxide.

[0089] The coprecipitation reaction was initiated by simultaneously feeding aqueous solutions of transition metal sulfate and sodium hydroxide at a flow rate ratio of 1.9, with a total flow rate of 8 hours for an average residence time. The transition metal solution contained Ni, Co, and Mn in a molar ratio of 6:2:2 and a total transition metal concentration of 1.65 mol / kg. The aqueous sodium hydroxide solution was a 25% by weight solution. The pH value was maintained at 11.9 by separately feeding aqueous sodium hydroxide. After the particle size stabilized, the resulting suspension was continuously removed from the stirred vessel. The resulting suspension was filtered, washed with distilled water, dried in air at 120°C, and sieved to obtain the mixed transition metal (TM) oxyhydroxide precursor TM-OH.1. The average particle size (D50) was 10 μm.

[0090] I.2 Synthesis of precursor TM-OH.2 Deionized water and 49 g of ammonium sulfate per kg of water were placed in a stirred tank reactor. The solution was heated to 55° C. and adjusted to a pH of 12 by adding aqueous sodium hydroxide.

[0091] The coprecipitation reaction was initiated by simultaneously feeding aqueous transition metal sulfate solutions and aqueous sodium hydroxide solutions at a flow rate ratio of 1.8, with a total flow rate of 8 hours and an average residence time of 8 hours. The transition metal solution contained Ni, Co, and Mn in a molar ratio of 8:1:1 and a total transition metal concentration of 1.65 mol / kg. The aqueous sodium hydroxide solution was a 25% by weight sodium hydroxide solution and a 25% by weight ammonia solution in a mass ratio of 6. The pH value was maintained at 12 by separately feeding the aqueous sodium hydroxide solution. Starting from the start of all feeds, the mother liquor was continuously removed. After 33 hours, all feed flows were stopped. The resulting suspension was filtered, washed with distilled water, dried in air at 120°C, and sieved to obtain the mixed transition metal (TM) oxyhydroxide precursor TM-OH.2. The average particle size (D50) was 10 μm.

[0092] II. Cathode Active Material Manufacturing and Quality Control II.1 Process (a)~(d) Step (a.1): CAM-1.1: The mixed transition metal oxyhydroxide precursor TM-OH.1 was mixed with Al2O3 (average particle size 6 nm) and LiOH monohydrate to obtain a mixed powder with an Al concentration of 0.3 mol% relative to Ni+Co+Mn+Al and a Li / (TM+Al) molar ratio of 1.01.

[0093] Step (b.1): The mixture from step (a.1) was transferred into saggers with a 4 kg load. The saggers were arranged in a row of 6 saggers before entering the roller hearth kiln.

[0094] Step (c.1): The sagger from step (b.1) containing the mixture from step (a.1) was heated to 885°C in a roller hearth kiln in a forced flow of 100% oxygen with a residence time in the heating zone of 8 hours to obtain electrode active material CAM-1.1.

[0095] Step (d.1): After leaving the heating zone, the sagger containing CAM-1.1 was exposed to ambient temperature and allowed to cool to ambient temperature in a closed transfer system purged with dry nitrogen.

[0096] The CAM-1.1 was then deagglomerated in an air classifier mill.

[0097] CAM-2.1 Step (a.2): The resulting mixed transition metal oxyhydroxide precursor TM-OH.2 was mixed with LiOH monohydrate to obtain a concentration relative to Ni+Co+Mn+Al and a Li / (TM+Al) molar ratio of 1.04.

[0098] Step (b.2): The mixture from step (a.2) was transferred into saggers with a 4 kg load. The saggers were arranged in a row of 6 saggers before entering the roller hearth kiln.

[0099] Step (c.2): The sagger from step (b.2) containing the mixture from step (a.2) was heated to 815°C in the roller hearth kiln in a forced flow of 100% oxygen for a residence time in the heating zone of 8 hours to obtain electrode active material CAM-2.1.

[0100] Step (d.2): After leaving the heating zone, the sagger containing CAM-2.1 was exposed to ambient temperature and allowed to cool to ambient temperature in a closed transfer system purged with dry nitrogen.

[0101] [Table 1]

[0102] Steps (e) to (g) were carried out with the aid of a robot connected to a processing unit in the form of a computer which carried out the entire description of steps (e) to (g).

[0103] Process (e.1) After step (d.1), a robotic arm took several small samples of 1 g of CAM-1.1 from one of every fourth row of saggers for further analysis. For this purpose, the samples were divided into containers by a robotic arm, and another robotic arm closed the containers with caps to avoid moisture uptake. The closed containers were then transferred to another section for analysis and electrode treatment.

[0104] Process (f.1) One gram of CAM-1.1 in one container was transferred to an automated XRD instrument to measure the powder pattern of the sample. Another 1 gram of CAM-1.1 sample was transferred to an automated Karl Fischer titrator to measure the water content of the CAM-1.1 material, and another 5 grams of CAM-1.1 was used for automated BET surface area measurements.

[0105] Step (g.1): In electrode preparation, a robotic arm removed the cap of the container and injected a mixture of carbon black and binder dissolved in NMP into CAM-1.1 (details of the slurry composition are provided in Section II.1). The resulting mixture was stirred in a high-shear mixer and cast onto 20 μm-thick aluminum foil using an automated doctor blade system. The coated aluminum foil was transferred to a drying chamber to obtain electrode foils for coin cell testing. A robotic arm equipped with a 14 mm diameter punching die punched multiple disks from the foil to obtain the final electrode shape for coin cells. The electrode disks were then transferred to a pressing device to press the electrode disks into a 3.0 g / cm electrode density. 3 The electrode was compressed to a thickness of 100 μm. The compressed electrode was transferred to a holder equipped with a portion of the 2032 case, which is the housing of the coin cell. The compressed electrode disk was placed in a cell case placed by a robotic arm, and the separator and anode were stacked on top of the electrode disk. In the final step, the robotic arm added 50 μL of electrolyte to the assembled electrode-separator combination of the resulting coin cell using a pipette. The robot then closed the coin cell and moved it for coin cell testing.

[0106] Steps (e.2) to (g.2) were carried out in the same manner, except that CAM-2.1 was used instead of CAM-1.1.

[0107] III. Electrochemical Cell III.1. Fabrication of electrodes for electrochemical testing Positive electrodes for electrochemical cycling experiments in coin cells were prepared by coating (thickness = 20 μm) each of the cathode active materials (a slurry of 94 wt% cathode active material (94 wt%), 1 wt% activated carbon (Imerys Super C65 L), 2 wt% graphite (Imerys SFG6L), and 3 wt% polyvinylidene fluoride (PVdF) binder suspended in N-methyl-2-pyrrolidinone (NMP)) onto aluminum foil using an automated doctor knife coating system and then drying (Mathis, KTF-S). Typically, all slurries were prepared based on at least 30 g of cathode active material, and the amount of NMP used was such that the total solids content (CAM + Super C65 L + SFG6L + PVdF) was approximately 65%. Before cell assembly, the electrode tapes were dried in a hot air chamber at 120 °C for 16 h and finally pressed using a roll calender.

[0108] III.2. Electrochemical Tests in Half Cells Coin-type half cell (vs. 4.3V vs. Li / Li + Electrochemical testing of the cathode active materials (CAM-1.1, CAM-2.1) was performed to obtain the specific capacitance of the materials using Li metal as the anode material with an upper cutoff voltage of 1000 kJ / cm2, 1 M LiPF in EC:EMC (EC = ethylene carbonate, EMC = ethyl methyl carbonate) by weight as the electrolyte, GF / D glass fiber separator (Whatman), and CR2032 (manufactured by HOHSEN Corp.).

[0109] [Table 2]

[0110] Data from the electrochemical tests was collected as input through an input channel of a processor in the form of a computer. The computer compared the initial charge and discharge capacities and first cycle efficiencies with target capacities and efficiencies. The processor automatically provided an electronic signal through an output channel to a production control function when at least two consecutive samples showed a negative deviation from specification of about 1%.

Claims

1. The following steps: (a) mixing a composite oxide, composite (oxy)hydroxide, composite hydroxide, or composite carbonate of nickel and at least one of cobalt and manganese with at least one lithium source selected from lithium carbonate, lithium oxide, and lithium hydroxide; (c) firing the mixture in a pusher kiln, roller hearth kiln, or rotary kiln at a temperature in the range of 700°C to 1000°C; (d) cooling the obtained electrode active material; (e) applying a robot to take at least two samples to be analyzed, each of 10 mg to 10 g, per sagger, crucible or open cup, or per defined period; (f) transferring the samples to another robot or to another part of the same robot, each robot producing an electrode material mixture from the same sagger, crucible or open cup of electrode material sample; (g) transferring the electrode material mixture to a test unit for electrochemical testing; Including, The method for producing an electrode active material, wherein the robot performs steps (f) to (g) on ​​a plurality of samples in parallel.

2. The method described in claim 1, wherein in step (a), at least one of Mg, Al and Y, or a transition metal selected from Ti, Zr, Nb, Ta, Fe, Mo and W is further mixed.

3. The method of claim 1, wherein in step (a), at least one dopant selected from oxides, hydroxides and oxyhydroxides of Mg, Al, Y, Ti, Zr, Nb, Ta, Fe, Mo and W, and from fluorides, is further mixed.

4. A method according to any one of claims 1 to 3, further comprising the step of (b) transferring the mixture obtained from step (a) into a sagger, crucible or open cup.

5. 5. The method of claim 1, wherein step (f) comprises mixing the electrode active material with conductive carbon, a binder, and NMP.

6. 6. The method according to claim 1, wherein step (f) is carried out in a molding die having a number of depressions arranged in an array, or in the wells of a microtiter plate.

7. 7. The method of any one of claims 1 to 6, wherein the transferring in step (g) is carried out with the aid of an electronic pipette or an overhead weight distribution unit.

8. 8. The method of claim 1, wherein in step (e), samples are taken from one of every 5 to 12 saggers, crucibles or open cups per production run.

9. Step (g) comprises the following substeps: (g1) disposing each electrode material mixture on a current collector; (g2) removing volatile materials from the electrode material mixture on the current collector, thereby obtaining a cathode; (g3) attaching the obtained cathode to a separator combined with an anode and an electrolyte, thereby obtaining a coin cell; (g4) performing electrochemical testing using the coin cell from substep (g3); and 9. The method of claim 1, comprising:

10. 10. The method of any one of claims 1 to 9, wherein the entire recitation of steps (e) to (g) is performed by a processor, and the results of the electrochemical test are compared to the desired results by the processor.

11. 11. The method of claim 10, wherein the processing device collects data as input via an input channel and provides an electronic signal via an output channel to a production control function when at least two consecutive samples indicate a negative deviation from the desired result.

12. 1. A system of equipment comprising a robot having a device for taking a 10 mg to 10 g sample of electrode active material, means for transferring said sample to another robot or to another part of the same robot, and means for transferring an electrode material mixture to a testing unit for electrochemical testing, wherein said robot produces an electrode material mixture from the sample.

13. 13. The system of claim 12, wherein the results of the electrochemical test are compared to a desired result.

14. 14. The arrangement of claim 12 or 13, further comprising a processing device that collects data as input via an input channel and provides an electronic signal via an output channel to a production control function when at least two consecutive samples indicate a negative deviation from a desired result.

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