Method for manufacturing cathode active material and precursor thereof

Abstract

The invention relates to a method for producing a particulate (oxy) hydroxide of TM, in which TM comprises nickel and a transition metal selected from Co and Mn and at least one further element selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta, the method comprises the following steps: (a) providing an aqueous solution (alpha) containing sulfates of water-soluble compounds of Ni and of at least one transition metal selected from Co and Mn and of at least one additional metal selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta and an aqueous solution (beta) containing an alkali metal hydroxide and optionally an aqueous solution (gamma) containing ammonia, (b) combining solution (alpha) and solution (beta) and, if applicable, solution (gamma) in a stirred tank reactor at a pH value in the range of 12.5 to 14.0, thereby producing particles containing nickel hydroxide, said particles being pulpified, (c) adding solution (alpha) and solution (beta) and-if applicable-solution (gamma) to the slurry from step (b) in a stirred tank reactor at a pH in the range of 9.6 to 11.6, thereby growing particles of hydroxide of TM, (d) terminating the addition of solution (alpha) but continuing the addition of solution (beta) and-if applicable-solution (gamma), and (e) removing the particulate (oxygen) hydroxide of TM by means of a solid / liquid separation process, followed by drying.

Description

[0001] The present invention relates to a process for the manufacture of particulate (oxy)hydroxides or oxides of a TM, wherein the TM comprises nickel and one transition metal selected from Co and Mn and at least one further element selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta, and wherein the process comprises the following steps:

[0002] (a) providing an aqueous solution (a) of a sulfate of a water-soluble compound containing Ni and at least one transition metal selected from Co and Mn and at least one further metal selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta and an aqueous solution (β) containing an alkali hydroxide and optionally an aqueous solution (γ) containing ammonia,

[0003] (b) combining solution (a) and solution (β) and, if applicable, solution (γ) in a stirred tank reactor at a pH value in the range of 12.5 to 14.0, thereby generating nickel-containing hydroxide particles which are slurried,

[0004] (c) adding solution (a) and solution (β) and, if applicable, solution (γ) to the slurry from step (b) in a stirred tank reactor at a pH value in the range of 9.6 to 11.6, thereby growing particles of the hydroxide of the TM in the stirred tank reactor, thereby growing particles of the hydroxide of the TM,

[0005] (d) terminating the addition of solution (a) but continuing the addition of solution (β) and, if applicable, solution (γ) to adjust the pH value to 12.0 to 14.0, and

[0006] (e) removing the particulate hydroxide of the TM by a solid / liquid separation method followed by drying.

[0007] Lithiated transition metal oxides are currently used as electrode active materials for lithium ion batteries. In the past years a lot of research and development work has been performed to improve properties like charge density, specific energy and also other properties like cycle life reduction and capacity loss which can adversely affect the lifetime or suitability of lithium ion batteries. Additional efforts have been made to improve the manufacturing process.

[0008] In a typical process for manufacturing a cathode material for a lithium ion battery, a so-called precursor is first formed by co-precipitation of the transition metals as carbonates, oxides or preferably as hydroxides which can or can not be basic, such as oxyhydroxides. The precursor is then mixed with a lithium source, such as but not limited to LiOH, Li20 or Li2CC>3, and calcined at high temperature (firing). The lithium source(s) can be employed as hydrate(s) or in dehydrated form. The calcination (or firing), also often referred to as heat treatment or heating treatment of the precursor, is usually carried out at temperatures in the range of 600 °C to 1000 °C. During the heat treatment a solid state reaction occurs and the electrode active material is formed. The heat treatment is carried out in the heating zone of an oven or kiln.

[0009] To a large extent, the properties of the precursor are translated to some extent into the properties of the corresponding cathode active material, such as particle size distribution, content of the respective transition metal, etc. It is thus possible to influence the properties of the cathode active material by controlling the properties of the precursor.

[0010] Certain impurities introduced during the precursor manufacturing are difficult to remove. They remain in the cathode active material. In case such impurities are disadvantageous, methods to avoid such impurities are highly desirable.

[0011] One undesirable impurity is sulfate, such as Li2S04, see for example EP 2 289 849 A1. Sulfate can easily be incorporated by being a starting material for the precursor manufacturing. Since sulfate, unlike chloride, does not cause corrosion problems and is generally the cheapest water-soluble salt of the transition metals, such as nickel and also cobalt and manganese, they are a desirable starting material. However, in the cathode active material, sulfate is undesirable because it can trap lithium during the calcination process, forming the electrochemically inactive compound Li2S04. In certain cases, Li2S04may generate nanopores in the crystallites of the cathode active material, which can deteriorate the performance of the cathode active material in lithium ion battery applications, see for example ACS Nano [ACS Nano] 2019, 13, 9, 10694-10704.

[0012] In particular, in cathode active materials made from recycled transition metals containing at least one of Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta, a higher sulfate content is undesirable. In particular, cathode active materials with a sulfate content of more than 1 wt% are subject to low processability and crystallinity.

[0013] It is an object of the present invention to provide a process allowing the production of a cathode active material having a low sulfate content. It is a further object of the present invention to provide a process allowing the production of a precursor having a low sulfate content. It is a further object of the present invention to provide a cathode active material having a low sulfate content and a suitable precursor, wherein such precursor can be easily made.

[0014] Thus, a process as defined in the opening paragraph has been found, which is hereinafter also defined as "process of the invention" or "process according to the invention". The process of the invention comprises at least three steps, which are hereinafter also referred to as step (a), step (b) and step (c), and step (d) and step (e) or - even more simply - as (a), (b), (c), (d) and (e), respectively. The process of the invention can comprise further - optional - steps. Steps (a) to (e) are performed in sequence. Steps (a) to (e) are described in more detail hereinafter. By the process of the invention, a precursor having a low sulfate content is obtained.

[0015] The process of the invention is a process for the manufacture of a particulate (oxy)hydroxide or oxide of TM. The particulate (oxy)hydroxide then acts as a precursor of a cathode active material and it can therefore also be referred to as a precursor.

[0016] In one embodiment of the invention, the resulting precursor consists of secondary particles, which are agglomerates of primary particles.

[0017] In one embodiment of the invention, the specific surface area (BET) of the resulting precursor is in the range of 1 to 70 m 2 The degassing temperature is 120 °C.

[0018] The precursor is a (oxy)hydroxide of TM, wherein TM comprises Ni and at least one metal selected from the group consisting of Co and Mn and optionally at least one further element selected from the group consisting of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta, preferably a combination of Al, W, Mg and Nb or a combination of Ti, Zr, Al and Mg.

[0019] In one embodiment of the invention, TM is a combination of metals according to general formula (I)

[0020] (Ni a Co b Mn c ) 1-d M d (I)

[0021] wherein

[0022] a is in the range of 0.6 to 0.95, preferably 0.8 to 0.94.

[0023] b is in the range of 0.025 to 0.2, preferably 0.025 to 0.15.

[0024] c is in the range of 0 to 0.2, preferably 0 to 0.15, and

[0025] d is in the range of 0.02 to 0.1.

[0026] M is selected from Mg, Al, Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta, preferably from Al, Mg, Nb, W, Ti and Zr, more preferably a combination of Mg and Al or a combination of Al, Mg, W and Nb or a combination of Mg and Al or a combination of Al, Mg, Ti and Zr.

[0027] a + b + c = 1 and b + c > 0, or M includes Al and d > 0.

[0028] In another embodiment of the invention, TM corresponds to general formula (II).

[0029] (Ni a Co b Mn c ) 1-d M d (II)

[0030] in

[0031] a is in the range of 0.25 to 0.4.

[0032] b is in the range of 0 to 0.2.

[0033] c is in the range of 0.6 to 0.75, and

[0034] d is in the range of 0.02 to 0.1.

[0035] M is selected from Mg, Ca, Si, Al, Ti, Zr, Mo, W, Al, Mg, Nb, and Ta, and is preferably selected from Al, Mg, Nb, W, Ti, and Zr.

[0036] a + b + c = 1.

[0037] In each case, the TM may contain trace amounts of other metal ions besides those described above, such as trace amounts of commonly present metals like sodium, iron, or zinc as impurities, but such trace amounts will not be considered in the description of this invention. In this context, trace amounts will mean an amount of 0.05 mol-% or less relative to the total metal content of the TM.

[0038] As used herein, the precursor is a particulate material. In one embodiment of the invention, the precursor has an average particle size D50 in the range of 3 to 20 µm, preferably 4 to 16 µm. The average particle size can be determined, for example, by light scattering or laser diffraction or electron-acoustic spectroscopy. These particles consist of primary particles, and in particular, they are agglomerates of primary particles, and the aforementioned particle size refers to the diameter of the secondary particles. Although (D50)—strictly speaking—is a median rather than an average diameter, the two expressions are used interchangeably.

[0039] In one embodiment of the invention, the particle size distribution of the precursor spans from 0.2 to 2.0, preferably from 0.25 to 0.35, or from 0.6 to 1.5. The span is defined as [(D90) - (D10)] / (D50), where the values ​​of (D90), (D50), and (D10) are determined by dynamic light scattering or by X-ray diffraction.

[0040] The precursor particles may have irregular shapes, but in preferred embodiments, the particulate material has a regular shape, such as quasi-spherical or even spherical. The aspect ratio can range from 1 to 10, preferably 1 to 3, and even more preferably 1 to 1.5. The aspect ratio is defined as the ratio of width to length, or specifically, the ratio of the particle diameter in the longest dimension to the particle diameter in the shortest dimension. A perfectly spherical particle has an aspect ratio of 1.

[0041] Step (a) includes providing an aqueous solution (α) of a sulfate containing at least one water-soluble compound of Ni and at least one transition metal selected from Co and Mn and at least one other metal selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta, an aqueous solution (β) containing an alkali metal hydroxide, and an aqueous solution (γ) optionally containing a complexing agent (e.g., ammonia).

[0042] In one embodiment of the invention, the nickel sulfate used as a raw material in step (a) is at least partially produced by recycling lithium-ion batteries. This recycling preferably involves mechanical treatment of waste batteries or substandard electrochemical battery cells, followed by one or more chemical processes such as leaching or at least one smelting process, followed by the redissolution of any reduced metal. Although not strictly recycling, in the context of this invention, the reintroduction of substandard cathode active material is included in the term "recycling." Depending on the recycling method used, nickel is obtained containing at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta in measurable amounts, preferably at least two of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta, for example, from 0.01% to 1.5% by weight, preferably at least one of Al, Mg, Nb, W, Ti, and Zr, more preferably a combination of Mg and Al, or a combination of Al, Mg, W, and Nb, or a combination of Mg and Al, or a combination of Al, Mg, Ti, and Zr.

[0043] In the context of this invention, the term "water-soluble compound" refers to a compound that has a solubility in water of at least 10 g / L at 20°C.

[0044] The term "water-soluble compounds of aluminum" refers to compounds such as Al2(SO4)3, Al(NO3)3, KAl(SO4)2, NaAlO2, and NaAl(OH)4. Depending on the choice of water-soluble aluminum compound, the pH of the aqueous solution (α) can range from 1 to 3 or be higher than 13.

[0045] Examples of suitable Mg compounds are MgSO4, Mg(NO3)2, magnesium acetate and MgCl2, with MgSO4 being preferred.

[0046] Suitable examples of Ca compounds are Ca(NO3)2, calcium acetate, and CaCl2.

[0047] Examples of suitable Si compounds are sodium metasilicate, sodium orthosilicate, and silicic acid.

[0048] Examples of suitable Ti compounds are Ti(SO4)2, TiOSO4, TiO(NO3)2, and Ti(NO3)4, with Ti(SO4)2 being preferred.

[0049] Examples of suitable Zr compounds are zirconium acetate, Zr(SO4)2, ZrOSO4, ZrO(NO3)2, and Zr(NO3)4, with Zr(SO4)2 being preferred.

[0050] Examples of suitable Nb compounds are (NH4)Nb(C2O4)3 and (NH4)NbO(C2O4)2. Examples of suitable Mo compounds are MoO3, Na2MoO4 and (NH4)2MoO4.

[0051] Examples of suitable compounds containing W are WO3, WO3·H2O, Na2WO4, ammonium tungstate, and tungstic acid.

[0052] Solution (α) can have a pH value in the range of 2 to 6. In embodiments where a higher pH value is desired, ammonia may be added to solution (α). However, it is preferable not to add ammonia to solution (α). In cases where the aim is to provide a solution containing NaAlO2 and NaAl(OH)4, it is preferable to provide at least two aqueous solutions, one containing at least one of nickel, cobalt, and manganese, and optionally at least one of Ti, Zr, Mo, W, Mg, Nb, and Ta, and the other aqueous solution containing either NaAlO2 or NaAl(OH)4.

[0053] The concentrations of nickel and other components of TM (as applicable) can be selected within a wide range. Preferably, the corresponding total metal concentration is selected to be in the range of 1 to 1.8 mol metal / kg solution, more preferably 1.3 to 1.7 mol metal / kg solution.

[0054] Furthermore, in step (a), an aqueous solution of an alkali metal hydroxide, hereinafter also referred to as solution (β), is provided. Examples of alkali metal hydroxides are potassium hydroxide and combinations of sodium hydroxide and potassium hydroxide, and even more preferably sodium hydroxide.

[0055] In one embodiment of the invention, the solution (β) mainly contains an alkali metal hydroxide and a certain amount (e.g., 0.1% to 2% by weight relative to the corresponding amount of the alkali metal hydroxide) of carbonate intentionally added or added by aging of the solution (β) or the corresponding alkali metal hydroxide.

[0056] The solution (β) may have a hydroxide concentration in the range of 0.1 to 12 mol / L, preferably 6 to 10 mol / L.

[0057] The pH of the solution (β) is preferably 13 or higher, for example 14.5.

[0058] The solution (γ) contains a complexing agent. Examples of complexing agents are ammonia and organic acids or their alkali metal or ammonium salts, wherein each molecule of the organic acid has at least two functional groups, and at least one of these functional groups is a carboxylic acid group.

[0059] Examples of organic acids with two identical functional groups are adipic acid, oxalic acid, succinic acid, and glutaric acid. An example of an organic acid with three identical functional groups is citric acid.

[0060] In one embodiment of the present invention, the organic acid is selected from malic acid, tartaric acid, citric acid and glycine.

[0061] In one embodiment of the invention, the concentration of one or more complexing agents in the solution (γ) is in the range of 1% to 30% by weight. In embodiments where the complexing agent is selected from ammonia, the concentration of the complexing agent is preferably in the range of 10% to 30% by weight. In embodiments where one or more complexing agents are selected from organic acids or their alkali metal salts or ammonium salts, wherein each molecule of said organic acid has at least two functional groups and at least one of these functional groups is a carboxylic acid group, the concentration of said complexing agent in the solution (γ) may be in the range of 0.2% to 10% by weight.

[0062] A more preferred complexing agent is ammonia.

[0063] In steps (b) and (c), solutions (α) and (β), and—if applicable—solution (γ), are combined under conditions of hydroxide precipitation. In step (b), hydroxide particles are substantially formed, and in step (c), these hydroxide particles are grown. The continuous phase is also referred to as the "mother liquor." The mother liquor contains sulfate ions and alkali metal ions from the base in solution (β).

[0064] Steps (b) and (c) can be carried out in the same stirred tank reactor or in a cascade of at least two stirred tank reactors, each equipped with an overflow system. Preferably, one or more stirred tank reactors are equipped with a solid-liquid separation device through which the mother liquor is removed. Examples of solid-liquid separation devices are clarifiers such as plate clarifiers and filtration devices such as filter presses, hydrocyclones, and filters (such as at least one candle filter). By using one or more of such solid-liquid separation devices, a slurry with a solids content of up to 1200 g / L can be obtained.

[0065] The percentage of mother liquor removed in steps (b) and (c) can be in the range of 200 to 1,200 g / l, preferably 800 to 1,200 g / l. However, despite the removal of the mother liquor, the slurry can still be well stirred.

[0066] Step (b) involves combining one or more solutions (α) and solutions (β) and—if applicable—solution (γ) in a continuous reactor to produce solid particles of TM hydroxide. These solid particles are then slurried.

[0067] In one embodiment of the invention, the particles produced by step (b) have an average diameter in the range of 2 to 10 µm, preferably 2 to 5 µm.

[0068] In step (b), the pH value of the liquid phase of the slurry is in the range of 12.5 to 14.0. The pH value is determined in the liquid phase at 23°C.

[0069] In one embodiment of the present invention, the average hydraulic residence time of the slurry in step (b) is in the range of 30 minutes to 16 hours, preferably in the range of 1 to 12 hours, and more preferably in the range of 2 to 8 hours.

[0070] In one embodiment of the invention, step (b) is performed at a temperature in the range of 10°C to 85°C, preferably in the range of 20°C to 70°C.

[0071] In one embodiment of the invention, step (b) is performed under constant pressure, such as ambient pressure. In other embodiments, step (b) is performed under elevated pressure, such as up to 50 bar.

[0072] In one embodiment of the invention, the mother liquor is removed from the continuous reactor during step (b). The mother liquor contains water and sodium sulfate.

[0073] After step (b), step (c) is performed. Step (c) may be performed in a different container or in the same container as step (b). In the latter case, the method of the present invention is performed in batches.

[0074] In one embodiment of the invention, the slurry transferred to step (c) – or to a storage container, see below – has a solids content in the range of 200 to 1200 g / L. Prior to the start of step (c), the slurry from step (b) is preferably diluted to 2 to 100 g / L in the reactor in which step (c) is carried out (e.g., with deionized water or with mother liquor). The solids content can be determined by density measurement or ICP (inductively coupled plasma) or by a Coriolis meter and refers to the slurried particles. In this context, dissolved compounds, such as, but not limited to, Na₂SO₄, are ignored.

[0075] In one embodiment of the invention, steps (b) – and (c) – are carried out under an inert atmosphere, such as nitrogen or a rare gas such as argon. Oxygen-deficient air (e.g., having up to 2% O2 by weight) is also feasible, especially when TM does not contain manganese. CO2 is not a suitable inert atmosphere due to the strong alkalinity of the solution (β).

[0076] In step (c), the slurry from step (b) is transferred to a stirred tank reactor that is operated continuously or preferably in batches, wherein solutions (α) and (β) and—if applicable—solution (γ) are combined.

[0077] In step (c), the pH of the liquid phase of the slurry is in the range of 9.6 to 11.6, preferably in the range of 9.8 to 11.2, and more preferably in the range of 10.0 to 10.8. The pH is determined at 23°C. A pH lower than that in step (b) can be achieved by reducing the ratio of hydroxide to the transition metal in solution (α), by reducing the amount of solution, or even by terminating the addition of solution (γ).

[0078] The solutions (α) and (β) in step (c), and—if applicable—solution (γ), are as defined above. These solutions may have the same composition or a different composition than their equivalents in step (b)—but within the framework of the definitions above, for example, one of these solutions contains a water-soluble salt of nickel and at least one of cobalt and manganese. In such cases, these solutions are also referred to as solution (α') and solution (β'), and—if applicable—solution (γ'), respectively. However, preferably, the composition of solution (α) is the same as in steps (b) and (c).

[0079] Even more preferably, the composition of solution (α) is the same in steps (b) and (c), and the composition of solution (β) is also the same in steps (b) and (c).

[0080] In one embodiment, step (c) is carried out in a batch-operated stirred tank reactor, and the composition of the solution (α)—or (α'), depending on the circumstances—changes during step (c), for example, the concentrations of nickel and cobalt or manganese. In another embodiment of the invention, the composition of the solution (α)—or (α'), depending on the circumstances—remains constant.

[0081] In one embodiment of the invention, the duration of step (c) is in the range of 30 minutes to 80 hours, preferably in the range of 10 to 70 hours, and more preferably in the range of 15 to 60 hours.

[0082] In one embodiment of the invention, step (c) is performed at a temperature in the range of 10°C to 85°C, preferably in the range of 20°C to 60°C.

[0083] In one embodiment of the invention, step (c) is performed under constant pressure, such as ambient pressure. In other embodiments, step (b) is performed under elevated pressure, such as up to 50 bar.

[0084] In one embodiment of the invention, the method of the invention is carried out in a cascade of at least two stirred tank reactors, wherein the first stirred tank reactor is equipped with an overflow system through which slurry is removed from the first stirred tank reactor and transferred directly or indirectly to the second stirred tank reactor.

[0085] In a preferred embodiment, the slurry is removed from the continuous stirred tank reactor in which step (b) is carried out and transferred to a stirred storage container, where it is stored under stirring for a period of 15 minutes to 24 hours, preferably 30 minutes to 10 hours, before being transferred to a second stirred tank reactor. This operation is also referred to as the storage step. During the storage step, neither solution (α) nor solution (β) nor solution (γ) is added. The storage is preferably carried out under an inert gas atmosphere (see above).

[0086] In one embodiment of the invention, the temperature during the storage step is in the range of 20°C to 70°C, preferably 30°C to 60°C.

[0087] In one embodiment of the invention, the pH value of the slurry in the storage container, determined at 23°C, is in the range of 10.0 to 13.0, preferably 12.0 to 12.5.

[0088] In one embodiment of the invention, at the same time, slurry in the range of 5 vol-% to 30 vol-%, preferably 10 vol-% to 20 vol-%, is in a storage container, and 70 vol-% to 95 vol-%, preferably 80 vol-% to 90 vol-%, of slurry is carried out in a batch reactor in which steps (b) and (c) are performed. In this context, the amount of slurry located in any pipes or related parts is ignored.

[0089] In one embodiment of the invention, the slurry in the storage container is occasionally stirred, for example using an average energy input of 0.2 to 1 W / l. This occasional stirring can help prevent the deposition of solids in the slurry.

[0090] By performing step (c), solid particles of hydroxide or oxyhydroxide are generated, which are then slurried. Thus, a slurry is obtained. Preferably, the slurry has a solids content in the range of 200 to 1,200 g / L.

[0091] In one embodiment of the invention, a clarifier or at least one candle filter is used for mother liquor removal. The one or more candle filters are connected to the stirring vessel in a manner that allows for easy removal of the mother liquor while leaving the solids in the stirring vessel.

[0092] In step (d), the addition of solution (α) to the slurry from step (c) is stopped, but the addition of solution (β) continues to adjust the pH to 12.0 to 14.0. Optionally, the addition of solution (γ) may continue, resume, or be performed for the first time. Preferably, in step (d), only solution (α) is added to the slurry from step (c).

[0093] In one embodiment of the invention, the temperature in step (d) is in the range of 30°C to 95°C. Preferably, any heating is initiated during step (d). More preferably, during step (d), the temperature is brought to ambient temperature or to a temperature at least 5°C lower than that in step (c).

[0094] Preferably, the slurry from step (c) is stirred during step (d), and preferably, stirring continues after pH adjustment according to step (d), for example, within a time period ranging from 1 minute to 24 hours, preferably from 5 minutes to 12 hours, and even more preferably from 15 minutes to 6 hours.

[0095] In one embodiment of the invention, the pH value in step (d) is adjusted to be at least 1 unit higher, preferably at least 1.5 units higher than that in step (c). The difference does not exceed 4.4 units. If the pH difference exceeds 4.5 units, for example 5 units, which is only possible by significantly reducing the pH value in step (c), the solubility of nickel and hydroxides of transition metals other than nickel becomes too high.

[0096] In one embodiment of the invention, the pH value in step (d) is adjusted to be at least 0.5 units higher, preferably at least one unit higher, than that in step (b).

[0097] In one embodiment of the invention, the mother liquor continues to be removed during step (d). In an alternative embodiment, the mother liquor is removed during steps (b) and (c)—or only during step (c)—but not during step (d).

[0098] In one embodiment of the invention, step (d) is carried out in a separate container connected via an overflow system to the container in which step (c) is carried out. In an alternative embodiment, steps (b) through (d) are carried out in the same container (e.g., a stirred tank reactor).

[0099] In one embodiment of the invention, step (d) is performed in the absence of oxygen. This means that step (d) is performed in an atmosphere of nitrogen or a rare gas such as argon. In the context of this invention, oxygen-deficient air with an oxygen content of less than 1.0 vol% is considered oxygen-free.

[0100] In step (e), the particulate (oxy) hydroxide of TM generated in the previous step is removed by a solid / liquid separation method and then dried.

[0101] In step (e), the particles from step (d) are separated from the liquid phase by a solid-liquid separation method, preferably by filtration or in a centrifuge. The liquid phase may also be referred to as the mother liquor. Filtration can be carried out, for example, on a belt filter or in a filter press.

[0102] To remove the mother liquor, it is preferable to wash the filter cake, for example with water or with an alkali metal hydroxide or alkali metal carbonate solution.

[0103] Filtration can be supported by suction or by pressure.

[0104] The solid / liquid separation step (e) can be carried out at any temperature where the water is in a liquid state, for example, from 5°C to 95°C, preferably from 20°C to 60°C.

[0105] Step (e) includes drying the solid material. Step (e) also includes heat treatment of the solid, such as in a drying oven, in a rotary kiln, or in a flash calcination furnace.

[0106] By performing the solid-liquid separation section of step (e), a solid material is obtained, which is a particulate (oxy) hydroxide or oxide of TM. This material typically has a high water content, for example, 1% to 30% by weight, and can be dried, for example, in air at a temperature ranging from 80°C to 150°C or under reduced pressure (“in vacuum”) to a water content ranging from 100 to 5,000 ppm, where ppm is by weight. The water content can be determined by drying in vacuum at 100°C until the weight remains constant. The water content can be determined by Karl-Fischer titration.

[0107] Upon drying, some hydroxyl groups can be removed as water, yielding hydroxide oxyhydroxide. In embodiments where drying is carried out in air, partial oxidation may occur, also producing TM hydroxide oxyhydroxide.

[0108] The drying time can range from 30 minutes to 12 hours.

[0109] In one embodiment of step (e), the wet solid material (filter cake) is introduced into the rotary kiln via a chute or vibrating chute, via a screw conveyor or screw conveyor, preferably via a screw conveyor having a single screw or multiple screws.

[0110] In one embodiment of the invention, step (e) is followed by heat treatment at a temperature ranging from 250°C to 500°C in the absence of a lithium source. This heat treatment can be carried out in an atmosphere of nitrogen, air, or oxygen or oxygen-enriched air. This heat treatment can be performed in a rotary kiln, in a moving bed, a fixed bed, or in a fluidized bed.

[0111] Another aspect of the invention relates to particulate (oxy) hydroxides or oxides of TM, hereinafter also referred to as the (oxy) hydroxides of the invention or the precursors of the invention. The precursors of the invention are advantageously prepared according to the method of the invention.

[0112] The precursor of the present invention is a (oxy)hydride or oxide of TM, wherein TM comprises nickel and a transition metal selected from Co and Mn, and at least one other element selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta. Preferably, TM is a combination according to formula (I), see above.

[0113] The precursor of the present invention, as a (oxy)hydroxide or oxide, has a sulfate content in the range of 0.01% to 0.75% by weight, preferably 0.1% to 0.5% by weight, as determined by catalytic combustion of sulfur; and a content of at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta in the range of 0.01% to 1.5% by weight, wherein the sulfate and at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta are uniformly dispersed within the primary particles of the precursor of the present invention. Preferably, the total content of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta is in the range of 0.05% to 1.0% by weight. Even more preferably, a combination of Al, W, Mg, and Nb or a combination of Ti, Zr, Al, and Mg is 0.05% to 1.0%. The sulfate is preferably uniformly dispersed within the diameter of the precursor particles.

[0114] The precursor of the present invention has an average particle size (D50) in the range of 3 to 20 µm, preferably 5 to 15 µm and more preferably 6 to 12 µm, as determined by dynamic light scattering.

[0115] In one embodiment of the invention, the precursor of the invention is selected from oxyhydroxides and oxides, such as TM whose average oxidation state is in the range of +2.1 to +2.6 as determined by iodometric titration.

[0116] In one embodiment of the invention, the precursor of the invention is composed of secondary particles comprising primary particles having an asymmetric plate-like shape having a thickness of 20 to 200 nm and a length of 50 to 500 nm.

[0117] In one embodiment of the invention, the primary particles are substantially radially aligned. The radially aligned portions of the primary particles can be determined, for example, by performing SEM (scanning electron microscopy) on cross-sections of at least five arbitrarily selected secondary particles.

[0118] "Basically radial alignment" does not require perfect radial orientation, but rather includes a deviation of up to 5 degrees from perfect radial orientation in SEM analysis.

[0119] The precursor of the present invention, as an oxide of TM, has a moisture content in the range of 100 to 10,000 ppm by weight, preferably 250 to 8,000 ppm, and more preferably 300 to 5,000 ppm. The moisture content can be determined by Karl Fischer titration.

[0120] The precursors of the present invention, which are (oxy)hydrides and oxides of the present invention, are preferably obtained according to the method of the present invention. The precursors of the present invention are excellent starting materials for cathode active materials, suitable for producing batteries with high volumetric energy density due to low levels of inactive impurities and excellent cycle stability due to reduced parasitic side reactions of impurities within the electrochemical cell. Undesirable lithium consumption during calcination can be avoided.

[0121] Another aspect of the invention relates to the use of the precursors of the invention in the manufacture of cathode active materials, for example, for lithium-ion batteries. Another aspect of the invention is a method for manufacturing cathode active materials for lithium-ion batteries using the precursors of the invention, hereinafter also referred to as the calcination of the invention. This calcination of the invention can be carried out by mixing with a lithium source (e.g., LiOH, Li₂O₂, or Li₂CO₃) followed by calcination (e.g., at a temperature in the range of 600°C to 1000°C). Particularly in embodiments where the TM of the (oxygen) hydroxide of the invention corresponds to formula (I), the calcination is preferably carried out in an atmosphere of oxygen or oxygen-enriched air, for example, having at least 60 vol-% oxygen, preferably 80 vol-% oxygen, and more preferably at least 90 vol-% oxygen. In embodiments where the TM of the (oxygen) hydroxide of the invention corresponds to formula (II), the calcination can be carried out in an air atmosphere.

[0122] Examples of suitable setups for the calcination are rotary kilns, roller hearth kilns, and pusher kilns.

[0123] By calcining in the manner described above, substantially radially aligned primary particles—for example, up to at least 80%, preferably up to at least 90%—are retained, and a cathode active material with excellent capacity retention is obtained.

[0124] Specifically, the calcination of the present invention includes the following steps: mixing the precursor of the present invention—as a (oxy) hydroxide or oxide—with a lithium source and optionally with an oxide or (oxy) hydroxide of at least one of Nb, Al, Ti or Zr, and heat-treating the resulting mixture at a temperature in the range of 650°C to 1000°C in one or more steps.

[0125] In one embodiment of the invention, the mixing duration is from 10 minutes to 2 hours.

[0126] The mixing of the precursor, lithium compound source, and oxides or hydroxides of aluminum, Zr, Ti, Nb, or Ta can be carried out entirely in one step or in multiple sub-steps, for example, by first mixing the lithium compound source with the aluminum oxide or hydroxide and then combining this mixture with the precursor, or by first mixing the precursor with the lithium source and then adding the aluminum oxide or hydroxide, or by first mixing the aluminum oxide or hydroxide with the precursor and then adding the lithium source. Preferably, the precursor is first mixed with the lithium compound source and then the aluminum oxide or hydroxide is added.

[0127] Although organic solvents, such as glycerol or ethylene glycol, or water can be added to this mixture, it is preferred to carry out this mixture in a dry state without adding water or organic solvents.

[0128] The mixture is then subjected to a heat treatment at a temperature in the range of 650°C to 1000°C, preferably 650°C to 850°C.

[0129] In one embodiment of the invention, a mixture of the precursor and lithium source, as well as oxides or hydroxides of aluminum, Zr, Ti, Nb, or Ta, and optionally one or more solvents, is heated to 700°C to 1000°C at a heating rate of 0.1°C / min to 10°C / min.

[0130] In one embodiment of the invention, the temperature is gradually increased and then reaches a desired temperature of 700°C to 1000°C, preferably 750°C to 900°C. For example, the mixture of the precursor, lithium source, and Al oxide or hydroxide is first heated to a temperature of 350°C to 550°C and then held constant for 10 minutes to 4 hours, and then raised to 650°C to up to 1000°C, preferably 650°C to 850°C.

[0131] In embodiments where at least one solvent is used for mixing, the one or more solvents are removed as part of a heat treatment process, for example, by filtering, evaporating, or distilling the one or more solvents. Evaporation and distillation are preferred.

[0132] In one embodiment of the invention, the heat treatment is carried out in a roller hearth kiln, a pusher kiln, or a rotary kiln, or a combination of at least two of the foregoing. The advantage of a rotary kiln is that the material produced therein exhibits excellent homogeneity. In both roller hearth kilns and pusher kilns, different reaction conditions for different steps can be easily set. Box furnaces, tube furnaces, and split-tube furnaces are also feasible in laboratory-scale experiments.

[0133] In one embodiment of the invention, the calcination is carried out in an oxygen-containing atmosphere, such as a nitrogen-air mixture, a rare gas-oxygen mixture, air, oxygen, or oxygen-enriched air. In a preferred embodiment, the atmosphere in the calcination of the invention is selected from air, oxygen, and oxygen-enriched air. Oxygen-enriched air can be, for example, a 50:50 mixture of air and oxygen by volume. Other options are a 1:2, 1:3, 2:1, and 3:1 mixture of air and oxygen by volume.

[0134] In one embodiment of the invention, the calcination is carried out under a forced gas flow (e.g., air, oxygen, and oxygen-enriched air). This gas flow can be referred to as a forced gas flow. This gas flow can have a velocity of 0.5 to 15 m. 3 / h·kg according to the general formula Li1+x TM 1-x The specific flow rate of the O2 material is within a certain range. The volume is determined under the following standard conditions: 298 Kelvin and 1 atmosphere. The forced gas flow can be used to remove gaseous cracking products such as water and carbon dioxide.

[0135] In one embodiment of the invention, the calcination has a duration ranging from 1 hour to 30 hours, preferably 10 to 24 hours. Cooling time is ignored in this context.

[0136] The cathode active material thus obtained is cooled after heat treatment and before further processing. An additional—optional—step before further processing of the resulting electrode active material is a sieving and depolymerization step.

[0137] By performing the calcination method of the present invention, a cathode active material with excellent properties can be obtained in a simple way. Preferably, the electrode active material thus obtained has a molecular weight distribution of 0.1 to 0.8 μm as determined according to DIN-ISO 9277:2003-05. 2 Specific surface area (BET) in the range of / g.

[0138] Another aspect of the invention relates to cathode active materials, hereinafter also referred to as the cathode active materials of the invention. These are preferably prepared by calcination according to the invention.

[0139] The cathode active material of the present invention is based on the general formula Li 1+x TM 1-x The cathode active material is a particulate material containing O2, wherein x is in the range of 0 to 0.05 and TM comprises nickel and a transition metal selected from Co and Mn, and at least one other element selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta. The cathode active material has a sulfate content in the range of 0.01% to 0.75% by weight, preferably 0.1% to 0.5% by weight; and a content of at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta in the range of 0.01% to 1.5% by weight. The sulfate and at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb, and Ta are uniformly dispersed within the primary particles of the cathode active material, and the cathode active material has an average diameter (D50) in the range of 3 to 20 µm.

[0140] In one embodiment of the invention, the cathode active material of the invention has a residual lithium compound content in the range of 0.3% to 1.0% by weight, wherein the residual lithium compound is selected from lithium oxide, lithium hydroxide, lithium carbonate, and lithium sulfate. Lithium oxide, lithium hydroxide, and lithium carbonate can be detected by titration.

[0141] In one embodiment of the invention, it can be detected that Al or Zr or Ti or Mg or Ca or Si are uniformly distributed in the cathode active material obtained by the method according to the invention, without accumulation.

[0142] Preferably, the cathode active material of the present invention is composed of secondary particles, which are composed of primary particles.

[0143] In one embodiment of the present invention, the average primary particle size of the cathode active material of the present invention, as determined by SEM images, is 100 to 500 nm.

[0144] In one embodiment of the invention, the cathode active material of the invention has α-lattice parameters in the range of 2.873 to 2.875 Å, determined by X-ray diffraction and Rietveld refinement of the X-ray diffraction pattern.

[0145] In one embodiment of the invention, the cathode active material of the invention has a molecular weight distribution of 0.1 to 0.8 μm as determined according to DIN-ISO 9277:2003-05. 2 BET surface area within the range of / g. Degassing temperature is 200°C.

[0146] Another aspect of the invention relates to electrodes, and more particularly to cathodes, which are also referred to hereinafter as the cathodes of the invention. The cathode of the invention comprises...

[0147] (A) At least one cathode active material of the present invention.

[0148] (B) Carbon in a conductive form,

[0149] (C) At least one adhesive.

[0150] In a preferred embodiment of the present invention, the cathode of the present invention contains

[0151] (A) 80% to 99% by weight of the cathode active material of the present invention.

[0152] (B) Carbon, ranging from 0.5% to 19.5% by weight.

[0153] (C) 0.5% to 9.5% by weight of adhesive polymer,

[0154] The percentage is relative to the sum of (A), (B), and (C).

[0155] The cathode according to the present invention contains conductive modified carbon, also simply referred to as carbon (B). Carbon (B) can be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite. Carbon (B) can be added undisturbed during the preparation of the electrode material according to the present invention.

[0156] The electrodes according to the invention may contain additional components. These may include a current collector (D), such as, but not limited to, aluminum foil. They may further include a binder polymer (C), also referred to below as binder (C). The current collector (D) will not be described further here.

[0157] A suitable adhesive (C) is preferably selected from organic (co)polymers. Suitable (co)polymers, i.e., homopolymers or copolymers, can be selected, for example, from (co)polymers obtainable by anionic, catalytic, or free radical (co)polymerization, particularly 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. Furthermore, polyisoprene and polyacrylates are suitable. Polyacrylonitrile is particularly preferred.

[0158] In the context of this invention, polyacrylonitrile should be understood not only to polyacrylonitrile homopolymers, but also to copolymers of acrylonitrile with 1,3-butadiene or styrene. Polyacrylonitrile homopolymers are preferred.

[0159] In the context of this invention, polyethylene should be understood to mean not only homopolymer polyethylene, but also copolymers of ethylene comprising at least 50 mol% of copolyethylene and up to 50 mol% of at least one additional comonomer, such as α-olefins such as propylene, butene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, and isobutylene, vinyl aromatic compounds such as styrene, and (meth)acrylic acid, vinyl acetate, vinyl propionate, C1-C of (meth)acrylic acid. 10 alkyl esters, especially methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, as well as maleic acid, maleic anhydride and itaconic anhydride. Polyethylene can be HDPE or LDPE.

[0160] In the context of this invention, polypropylene should be understood not only to homopolymer polypropylene but also to copolymers of propylene comprising at least 50 mol% copolypropylene and up to 50 mol% of at least one additional comonomer, such as ethylene and α-olefins such as butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-pentene. The polypropylene is preferably isotactic or substantially isotactic polypropylene.

[0161] In the context of this invention, polystyrene should be understood not only to homopolymers of styrene, but also to C1-C polymers of acrylonitrile, 1,3-butadiene, (meth)acrylic acid, and (meth)acrylic acid. 10 α-alkyl esters, divinylbenzene, especially copolymers of 1,3-divinylbenzene, 1,2-diphenylethylene and α-methylstyrene.

[0162] Another preferred adhesive (C) is polybutadiene.

[0163] Other suitable adhesives (C) are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimide and polyvinyl alcohol.

[0164] In one embodiment of the invention, the adhesive (C) is selected from those having an average molecular weight M in the range of 50,000 to 1,000,000 g / mol, preferably up to 500,000 g / mol. w Those (co)polymers.

[0165] The adhesive (C) can be a crosslinked or non-crosslinked (co)polymer.

[0166] In a particularly preferred embodiment of the invention, the adhesive (C) is selected from halogenated (co)polymers, especially fluorinated (co)polymers. Halogenated or fluorinated (co)polymers should be understood to mean those (co)polymers comprising at least one (co)polymerized (co)monomer, each molecule of which has at least one halogen atom or at least one fluorine atom, more preferably each molecule has at least two halogen atoms or at least two fluorine atoms. Examples are 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.

[0167] Suitable adhesives (C) are especially polyvinyl alcohol and halogenated (co)polymers, such as polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvinylidene fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.

[0168] Another aspect of the present invention is an electrochemical battery cell containing

[0169] (A) A cathode comprising the electrode active material (A), carbon (B), and binder (C) of the present invention.

[0170] (B) Anode, and

[0171] (C) At least one electrolyte.

[0172] Examples of cathode (1) have been described in detail above.

[0173] The anode (2) may contain at least one anodic active material, such as carbon (graphite), TiO2, lithium titanium oxide, silicon, or tin. In addition, the anode (2) may include a current collector, such as a metal foil like copper foil.

[0174] Electrolyte (3) may contain at least one non-aqueous solvent, at least one electrolyte salt and optionally additives.

[0175] The non-aqueous solvent of the electrolyte (3) may be liquid or solid at room temperature and is preferably selected from polymers, cyclic or acyclic ethers, cyclic and acyclic acetals, and cyclic or acyclic organic carbonates.

[0176] Examples of suitable polymers include, in particular, polyalkylene glycols, preferably poly-C1-C4-alkylene glycols, and especially polyethylene glycol. Here, polyethylene glycol may contain up to 20 mol% of one or more C1-C4-alkylene glycols. Polyalkylene glycols are preferably polyalkylene glycols having two methyl or ethyl terminals.

[0177] Suitable polyalkylene glycols, and especially suitable polyethylene glycols, have a molecular weight M. w It can be at least 400 g / mol.

[0178] Suitable polyalkylene glycols, and especially suitable polyethylene glycols, have a molecular weight M. w It can be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol.

[0179] Suitable examples of acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane, and 1,2-diethoxyethane, with 1,2-dimethoxyethane being preferred.

[0180] Suitable examples of cyclic ethers are tetrahydrofuran and 1,4-dioxane.

[0181] Suitable examples of acyclic acetals are, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane, and 1,1-diethoxyethane.

[0182] Suitable examples of cyclic acetals are 1,3-dioxanes and especially 1,3-dioxolane.

[0183] Suitable examples of acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

[0184] Suitable examples of cyclic organic carbonates are compounds having general formulas (II) and (III).

[0185]

[0186] Where R 1 R 2 and R 3 They may be the same or different and selected from hydrogen and C1-C4-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl, wherein R 2 and R 3 Preferably, not all of them are tert-butyl.

[0187] In a particularly preferred embodiment, R 1 It is methyl and R 2 and R 3 Each is hydrogen, or R 1 R 2 and R 3 Each is hydrogen.

[0188] Another preferred cyclic organic carbonate is vinylene carbonate, formula (IV).

[0189]

[0190] The one or more solvents are preferably used in an anhydrous state, i.e., wherein the water content is in the range of 1 ppm to 0.1% by weight, which can be determined, for example, by Karl Fischer titration.

[0191] Electrolyte (3) further comprises at least one electrolyte salt. Suitable electrolyte salts are, in particular, lithium salts. Examples of suitable lithium salts are LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, and LiC(C n F 2n+1 SO2)3, lithium iminoides such as LiN(C) n F 2n+1SO2)2, where n is an integer in the range of 1 to 20, LiN(SO2F)2, Li2SiF6, LiSbF6, LiAlCl4, and those with the general formula (C n F 2n+1 SO2) t A salt of YLi, where m is defined as follows:

[0192] When Y is selected from oxygen and sulfur, t = 1.

[0193] When Y is selected from nitrogen and phosphorus, t = 2, and

[0194] When Y is selected from carbon and silicon, t = 3.

[0195] The preferred electrolyte salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, and LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred.

[0196] In a preferred embodiment of the invention, the electrolyte (3) contains at least one flame retardant. Available flame retardants may be selected from trialkyl phosphates (where the alkyl groups are different or the same), triaryl phosphates, dialkyl alkyl phosphonates, and halogenated trialkyl phosphates. Preferred are tri-C1-C4-alkyl phosphates (where the C1-C4-alkyl groups are different or the same), tribenzyl phosphate, triphenyl phosphate, di-C1-C4-alkyl phosphonates, and fluorinated tri-C1-C4-alkyl phosphates.

[0197] In a preferred embodiment, the electrolyte (3) contains at least one flame retardant selected from trimethyl phosphate, CH3-P(O)(OCH3)2, triphenyl phosphate and tri-(2,2,2-trifluoroethyl)-phosphate.

[0198] The electrolyte (3) may contain 1% to 10% by weight of flame retardant based on the total amount of the electrolyte.

[0199] In embodiments of the invention, the battery according to the invention comprises one or more separators (4) by means of which electrodes are mechanically separated. Suitable separators (4) are polymer membranes, particularly porous polymer membranes, which are non-reactive to metallic lithium. Particularly suitable materials for separators (4) are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0200] Membranes (4) made of polyolefins, particularly polyethylene or polypropylene, can have a porosity in the range of 35% to 50%. Suitable pore sizes are, for example, in the range of 30 to 500 nm.

[0201] In another embodiment of the invention, the diaphragm (4) may be selected from PET nonwoven fabric filled with inorganic particles. Such diaphragms may have a porosity in the range of 40% to 55%. Suitable pore sizes are, for example, in the range of 80 to 750 nm.

[0202] The battery according to the invention may further include a housing, which may have any shape, such as a cubic or cylindrical disk. In one variant, a metal foil configured as a pouch is used as the housing.

[0203] The battery according to the invention provides very good discharge and cycle behavior, especially at high temperatures (45°C or higher, for example up to 60°C), particularly with regard to capacity loss.

[0204] A battery according to the invention may comprise two or more electrochemical battery cells combined with each other, which may be connected in series or in parallel, for example. Series connection is preferred. In a battery according to the invention, at least one of these electrochemical battery cells includes at least one electrode according to the invention. Preferably, in an electrochemical battery cell according to the invention, most of these electrochemical battery cells include an electrode according to the invention. Even more preferably, in a battery according to the invention, all electrochemical battery cells include an electrode according to the invention.

[0205] The present invention further provides the use of the battery according to the invention in devices, particularly in mobile devices. Examples of mobile devices are vehicles of transportation, such as cars, bicycles, airplanes, or water vehicles such as boats or ships. Other examples of mobile devices are those that are manually moved, such as computers (especially laptops), telephones, or electric hand tools (e.g. in the construction industry), especially drills, battery-powered screwdrivers, or battery-powered staplers.

[0206] The invention is further illustrated by working examples.

[0207] Nickel sulfate is produced as follows:

[0208] Discharged, spent lithium-ion batteries were shredded, crushed, and ground until a black powder was obtained. Current collectors from the electrodes were removed by sieving, and metallic iron was removed by magnetic separation. The resulting black substance was subjected to acid leaching with concentrated sulfuric acid and a reducing agent at a pH below 2.0 until all metals were dissolved. Remaining iron, aluminum, and copper impurities were depleted by precipitation and subsequent filtration after adjusting the pH of the resulting solution to 3. To further purify the metal solution, manganese and cobalt were recovered as aqueous sulfates by organic solvent extraction using kerosene as an organic solvent and di-(2-ethylhexyl)phosphoric acid as an extractant. This resulted in the following impurity distribution in the recovered NiSO4: 5.0 wt% Na2SO4, 0.12 wt% Al2(SO4)3, 0.07 wt% TiOSO4, 0.10 wt% ZrSO4, and 0.23 wt% MgSO4.

[0209] Provide the following aqueous solution, step (a.1):

[0210] Solution (α.1): NiSO4 synthesized above, commercially available CoSO4 and MnSO4 (all commercially available battery grade) dissolved in deionized water (molar ratio 91 : 4.5 : 4.5, total transition metal concentration: 1.45 mol / kg)

[0211] Solution (β.1): 25 wt% NaOH dissolved in deionized water

[0212] Solution (γ.1): 25 wt% ammonia in deionized water

[0213] I.1 Synthesis of the precursor P-CAM.1 of the present invention

[0214] 2.5 L of deionized water was added to a 3.0 L stirred vessel equipped with baffles, a cross-arm stirrer, and three feed tubes (one for aqueous solution (α.1), one for solution (β.1), and one for solution (γ.1)), and the vessel temperature was set to 55°C. The feed tube for the metal sulfate solution was separated by 8 cm from each of the other two tubes, while the tube for ammonia was separated by 2.5 cm from the tube for the NaOH solution. All tubes had an outer diameter of 6 mm and an inner diameter of 2 mm and were positioned within the vessel such that the corresponding outlet was approximately 5 cm below the liquid level. A constant nitrogen overflow was maintained in the vessel throughout the reaction.

[0215] The stirrer element operated at 1100 rpm. Aqueous solutions (α.1), (β.1), and (γ.1) were simultaneously introduced into the vessel through their respective tubes. The molar ratio between ammonia and the transition metal was adjusted to 0.25. Initially, the sum of the volumetric flow rates was set to adjust the residence time to 12.5 hours for a 1-hour reaction time, then linearly increased to 5 hours over 3 hours and remained constant thereafter within a 5-hour residence time. The flow rate of solution (β.1) was adjusted via a pH adjustment circuit to maintain the pH in the stirred vessel at a constant value of 12.5.

[0216] Step (c.1): After a 10-hour reaction time, the pH in the stirred tank is reduced by 1 unit to a constant pH of 11.5 by decreasing the feed (β.1). The pH and particle size of the growing (oxy)hydride particles are carefully controlled by sampling the reaction slurry. Throughout the reaction, the mother liquor is removed using a settling system.

[0217] Step (d.1): Once the particle size of 14 µm is reached, stop adding solution (α.1) and adjust the pH to 12.7 with stirring by continuing to add solution (β.1) for another 5 minutes.

[0218] Step (e.1): The resulting slurry was filtered, washed with deionized water and an aqueous sodium hydroxide solution (1 kg 25 wt% sodium hydroxide solution / kg solid hydroxide), and dried at 120°C for 12 hours to obtain the precursor P-CAM.1 of the present invention. P-CAM.1 has an average particle size (D50) of 13.9 µm, a (D90-D10) / D50 value of 0.4, a BET surface area of ​​14.3 m² / g, and a sulfate content of 0.66 wt%. P-CAM.1 has an Al content of 0.29 wt%, a Ti content of 0.33 wt%, a Zr content of 0.41 wt%, and a Mg content of 1.20 wt%. Sulfates are uniformly dispersed within the primary particles of P-CAM.1, as are Al, Zr, Ti, and Mg.

[0219] I.2: Synthesis of the comparative precursor CP-CAM.2

[0220] Repeat the above scheme, but omit step (d.1).

[0221] Step (e.1): The resulting slurry was filtered, washed with deionized water and an aqueous sodium hydroxide solution (1 kg 25 wt% sodium hydroxide solution / kg solid hydroxide), and dried at 120°C for 12 hours to obtain the comparative precursor CP-CAM.2. CP-CAM.2 had an average particle size (D50) of 14.0 µm, a (D90-D10) / D50 value of 0.4, a BET surface area of ​​14.2 m² / g, and a residual sulfate content of 1.0 wt%. The Al content was 0.35 wt%, the Ti content was 0.27 wt%, the Zr content was 0.40 wt%, and the Mg content was 1.00 wt%. Sulfates were uniformly dispersed within the primary particles of CP-CAM.1, as were Al, Zr, Ti, and Mg.

[0222] I.3 Manufacturing of the cathode active material CAM.1 of the present invention and the comparative cathode active material C-CAM.2:

[0223] The corresponding precursors were heat-treated at approximately 450°C for one hour. The pre-calcined materials were then mixed with LiOH∙H2O, Al2O3, and Zr(OH)4 in a molar ratio of 1.04:1 (Li:(Ni+Co+Mn), 0.006:1 (Al:(Ni+Co+Mn), and 0.003:1 (Zr:(Ni+Co+Mn)). The mixture was poured into an alumina crucible and heated to 765°C at a heating rate of 3°C / min under an oxygen atmosphere (10 air changes / hour) and held at this temperature for 8 hours. The resulting cathode active material was cooled to ambient temperature at a cooling rate of 10°C / min, washed with H2O at a ratio of 1:2 (H2O:cathode active material), and dried at 300°C for two hours. Subsequently, sieving was performed using a 30 µm sieve to obtain the cathode active material CAM.1 of the present invention from the precursor P-CAM.1 and the comparative cathode active material C-CAM.2 from the precursor CP-CAM.2.

[0224] In CAM.1, the sulfate content is approximately 0.6% by weight, and the sulfate is uniformly dispersed within the primary particles of CAM.1, as are Al, Ti, and Mg.

[0225] In C-CAM.2, the sulfate content is higher than 0.75% by weight, and the sulfate is uniformly dispersed in the primary particles of CAM.1, as are Al, Ti and Mg.

[0226] II. Testing of Cathode Active Materials

[0227] II.1 Cathode Manufacturing

[0228] Positive Electrode: PVDF binder (polyvinylidene fluoride, Solef® 5130) was dissolved in NMP (Merck) to produce a 7.5 wt.% solution. For electrode preparation, the binder solution (2.5 wt.%) and carbon black (Li400, 2.5 wt.%) were suspended in NMP. After mixing using a planetary centrifugal mixer (ARE-250, ThinkyCorp., Japan), CAM.1 or C-CAM.2 of the present invention (95 wt.%) was added, and the suspension was stirred again to obtain a lump-free slurry. The solids content of the slurry was adjusted to 65%. The slurry was coated onto Al foil using a KTF-S roll-to-roll coater (Mathis AG). All electrodes were calendered before use. The cathode material thickness was 85 µm, corresponding to 21 mg / cm². 2 Before assembling the battery, all electrodes were dried at 120°C for 7 hours.

[0229] II.2 Electrolyte Manufacturing

[0230] A substrate electrolyte composition EL matrix 1 (EL matrix 1) is prepared, comprising a total weight of 12.0 wt% LiPF6, 44.0 wt% ethylene carbonate (EC), and 44.0 wt% diethyl carbonate (DMC) based on EL matrix 1.

[0231] II.3 Testing Battery Cell Manufacturing - Button-type Half-cell Cell

[0232] A button-type half-cell cell (20 mm in diameter and 3.2 mm thick), comprising a cathode prepared as described in II.1 as the working electrode and lithium metal as the counter electrode, was assembled and sealed in an Ar-filled glove box. Furthermore, the cathode, anode, and separator were stacked in the order of cathode / / separator / / Li foil to produce the half-button cell. Subsequently, 0.15 mL of the EL matrix 1 described above (II.2) was introduced into the button cell.

[0233] II.4 Evaluation of Battery Cell Performance

[0234] Initial performance, C-rate performance, and cycle performance were measured as follows: Coin cell cells according to II.3 were tested at room temperature within a voltage range of 4.3 V to 2.7 V. For initial cycling, initial lithiation was performed in CC-CV mode, i.e., a constant current (CC) of 0.04 C was applied until 4.3 V was reached, followed by a CV step until the current dropped to 0.01 C. After a 10-minute rest period, reduction lithiation was performed at a constant current of 0.04 C until 27 V was reached. For C-rate testing, the charge and discharge rates were adjusted accordingly. For cycle testing, a constant current of 0.33 C was selected until 56 cycles were achieved.

[0235] After 56 cycles of testing on graphite anodes, CAM.1 showed superior characteristics compared to C-CAM.2.

Claims

1. A process for the manufacture of particulate (oxy)hydroxides or oxides of a TM, wherein TM comprises nickel and one transition metal selected from Co and Mn and at least one further element selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta, and wherein the process comprises the following steps: (a) providing an aqueous solution of a sulfate salt of a water-soluble compound containing Ni and at least one transition metal selected from Co and Mn and at least one further metal selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta (a) and an aqueous solution containing an alkali hydroxide (β) and optionally an aqueous solution containing ammonia (γ), (b) combining solution (a) and solution (β) and, if applicable, solution (γ) in a stirred tank reactor at a pH value in the range of 12.5 to 14.0, thereby generating particles of a nickel-containing hydroxide, which are slurried, (c) adding solution (a) and solution (β) and, if applicable, solution (γ) to the slurry from step (b) in a stirred tank reactor at a pH value in the range of 9.6 to 11.6, thereby growing particles of a hydroxide of TM, (d) terminating the addition of solution (a) but continuing the addition of solution (β) and, if applicable, solution (γ) to adjust the pH value to 12.0 to 14.0, and (e) removing the particulate hydroxide of TM by a solid / liquid separation method followed by drying.

2. The method of claim 1, wherein, TM is a combination of metals according to general formula (I) (Ni a Co b Mn c ) 1-d M d (I) wherein a is in the range of 0.6 to 0.95, b is in the range of 0.025 to 0.2, c is in the range of 0 to 0.2, and d is in the range of 0.02 to 0.1, M is selected from Mg, Al, Ca, Si, Ti, Zr, Mo, W, Nb and Ta, a + b + c = 1.

3. The method of claim 1 or 2, wherein, The nickel sulfate is at least partially made by recycling of lithium ion batteries.

4. The method according to any of the preceding claims, wherein, Step (d) is carried out in the absence of oxygen.

5. The method according to any one of the preceding claims, wherein, The temperature in step (d) is in the range of 30 °C to 95 °C.

6. The method according to any one of the preceding claims, wherein, The pH value in step (d) is adjusted at least 1 unit higher than in step (c).

7. The method according to any one of the preceding claims, wherein, The pH value in step (d) is adjusted at least 1 unit higher than in step (b).

8. The method of any of the preceding claims, wherein, The pH value in step (c) is lowered by reducing the addition of solution (β) until the desired pH value is obtained.

9. A process for the manufacture of an oxide precursor, which process comprises steps (a) to (e) according to claims 1 to 9 followed by a heat treatment in the absence of a lithium source at a temperature in the range of 250 °C to 500 °C.

10. A particulate (oxy)hydroxide of TM, wherein TM comprises nickel and one transition metal selected from Co and Mn and at least one further element selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta, wherein the (oxy)hydroxide has a sulfate content in the range of 0.01 to 0.75 % by weight and a content of at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta in the range of 0.01 to 1.5 % by weight, and wherein sulfate and the at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta are homogeneously dispersed within primary particles of the (oxy)hydroxide, and wherein the particulate (oxy)hydroxide has an average diameter (D50) in the range of 3 to 20 pm.

11. The particulate (oxy)hydroxide of claim 11, comprising secondary particles, which comprise primary particles having an asymmetric platelet shape with a thickness of 20 to 200 nm and a length of 50 to 500 nm.

12. A particulate oxide of TM, wherein TM comprises nickel and one transition metal selected from Co and Mn and at least one further element selected from Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta, wherein the (oxy)hydroxide has a sulfate content in the range of 0.01 to 0.75 % by weight and a content of at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta in the range of 0.01 to 1.5 % by weight, and wherein sulfate and the at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta are homogeneously dispersed within primary particles of the oxide, and an average diameter (D50) in the range of 3 to 20 pm, and wherein the particulate oxide of TM has a moisture content in the range of 100 to 10,000 ppm by weight.

13. A method of manufacturing a cathode active material for a lithium ion battery, the method comprising the steps of: Mixing the particulate (oxy)hydroxide of claim 11 or 12 or the particulate oxide of claim 13 with a lithium source and optionally with an oxide or (oxy)hydroxide of at least one of Nb, Al, Ti or Zr, and heat treating the resulting mixture in one or more steps at a temperature in the range of 650 °C to 1000 °C.

14. A cathode active material of the general formula Li 1+x TM 1-x O2, wherein, x is in the range of 0 to 0.05 and TM comprises nickel and one transition metal selected from Co and Mn and at least one further element selected from Ca, Si, Ti, Zr, Mo, W, Al, Mg, Nb and Ta, wherein the cathode active material has a sulfate content in the range of 0.01 to 0.75 % by weight and a content of at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta in the range of 0.01 to 1.5 % by weight, and wherein the sulfate and the at least one of Ti, Zr, Ca, Si, Mo, W, Al, Mg, Nb and Ta are homogeneously dispersed within the primary particles of the cathode active material and the average diameter (D50) is in the range of 3 to 20 pm.

15. The cathode active material according to claim 14 having a residual lithium compound content in the range of 0.3 to 1.0 % by weight, wherein the residual lithium compound is selected from lithium oxide, lithium hydroxide, lithium carbonate and lithium sulfate.

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