Method for producing coated electrode active material

Abstract

1. A method for producing a partially coated electrode active material, the method comprising the steps of: (a) General formula Li 1+x TM 1-x providing an electrode active material of O2, wherein TM is Ni, and optionally at least one of Co and Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, where x is in the range of 0 to 0.2, and at least 50 mol % of the transition metals in TM is Ni; (b) treating the electrode active material with an aqueous medium; (c) partially removing the water by solid-liquid separation; (d) treating the residue with a compound of Me, wherein Me is selected from at least one of aluminum, boron, phosphorus, antimony, magnesium, vanadium, and tellurium; (e) thermally treating the residue; Includes.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a partially coated electrode active material, wherein the method comprises the following steps: (a) General formula Li 1+x TM 1-x providing an electrode active material of O2, wherein TM is Ni, and optionally at least one of Co and Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, where x is in the range of −0.05 to 0.2, and at least 50 mol % of the transition metals in TM is Ni; (b) treating the electrode active material with an aqueous medium; (c) partially removing the water by solid-liquid separation; (d) treating the residue with a compound of Me, wherein Me is selected from at least one of aluminum, boron, phosphorus, molybdenum, antimony, vanadium, and tellurium; (e) thermally treating the residue; Includes. [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] Currently, particular interest is observed in so-called Ni-rich electrode active materials, for example, electrode active materials containing 75 mol % or more Ni relative to the total TM content.

[0004] One problem with lithium-ion batteries, especially with Ni-rich electrode active materials, is due to undesirable reactions at the surface of the electrode active material. Such reactions can be decomposition of the electrolyte, the solvent, or both. Therefore, attempts have been made to protect the surface without interfering with lithium exchange during charging and discharging. Examples include attempts to coat the electrode active material with, for example, aluminum oxide or calcium oxide (see, for example, U.S. Pat. No. 8,993,051).

[0005] Another theory attributes the undesired reaction to free LiOH or Li2CO3 on the surface. Attempts have been made to remove such free LiOH or Li2CO3 by washing the electrode active material with water (see, for example, JP 4,789,066 B, JP 5,139,024 B, and US2015 / 0372300). However, in some cases, it has been observed that the properties of the resulting electrode active material are not improved. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US 8,993,051 [Patent Document 2] JP 4,789,066 B [Patent Document 3] JP 5,139,024 B [Patent Document 4] US2015 / 0372300 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a method for producing an electrode active material rich in Ni having excellent electrochemical properties.An object of the present invention is to provide an electrode active material rich in Ni having excellent electrochemical properties. [Means for solving the problem]

[0008] We have therefore found a method as defined at the outset, which hereinafter is also called the "method of the invention", comprising the following steps: (a) General formula Li 1+x TM 1-x providing an electrode active material of O2, wherein TM is Ni, and optionally at least one of Co and Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, where x is in the range of −0.05 to 0.2, and at least 50 mol % of the transition metals in TM is Ni; (b) treating the electrode active material with an aqueous medium; (c) partially removing the water by solid-liquid separation; (d) treating the residue with a compound of Me, wherein Me is selected from at least one of molybdenum, antimony, vanadium, and tellurium; (e) thermally treating the residue; Includes. DETAILED DESCRIPTION OF THE INVENTION

[0009] The method of the present invention comprises five steps (a), (b), (c), (d), and (e), which are also referred to in the context of the present invention as steps (a), (b), (c), (d), and (e), respectively. Steps (b) and (c) may be initiated simultaneously or, preferably, sequentially. Steps (b) and (c) may be performed simultaneously or successively, preferably with at least partial overlap or simultaneous. Step (d) is performed after completion of step (c).

[0010] The method of the present invention involves the use of a compound of the general formula Li 1+x TM1-x The method starts with an electrode active material according to the formula: O2, where TM comprises Ni, optionally at least one transition metal selected from Co and Mn, and optionally at least one element selected from Al, Ba, B, and Mg, at least 50 mol % and preferably at least 75 mol % of TM is Ni, and x is in the range of -0.05 to 0.2. Said material is also referred to as starting material below.

[0011] In one embodiment of the present invention, the starting material has an average particle size (D50) in the range of 3 to 20 μm, preferably 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of agglomerates of primary particles, and the above particle size refers to the particle size of the secondary particles.

[0012] In one embodiment of the present invention, the starting material is 0.1 to 1.0 m 2 / g, the specific surface area (BET), hereinafter also referred to as "BET surface area", can be determined by nitrogen adsorption after outgassing the sample at 200°C for 30 minutes or more and beyond, according to DIN ISO 9277:2010.

[0013] In one embodiment of the present invention, the particulate material provided in step (a) has a water content, determined by Karl Fischer titration, in the range of 20 to 2,000 ppm, preferably 20 to 1,200 ppm.

[0014] In one embodiment of the invention, the variable TM corresponds to the general formula (Ia) (Ni a Co b Mn c ) 1-d M 1 d (I a) (wherein a+b+c=1, a is in the range of 0.75 to 0.95, preferably 0.85 to 0.95; b is in the range of 0.025 to 0.2, preferably 0.025 to 0.1, c is in the range of 0.025 to 0.2, preferably 0.05 to 0.1, d is in the range of 0 to 0.1, preferably 0 to 0.04; M 1 is at least one of Al, Mg, W, Mo, Ti or Zr, preferably at least one of Al, Ti and W).

[0015] In one embodiment of the present invention, the variable c is zero and M 1 is Al, and d is in the range of 0.01 to 0.05.

[0016] In another embodiment of the invention, the variable TM corresponds to the general formula (Ib) (Ni a* Co b* Al e* ) 1-d* M 2 d* (I b) (wherein a*+b*+c*=1, a* is in the range of 0.75 to 0.95, preferably 0.88 to 0.95; b* is in the range of 0.025 to 0.2, preferably 0.025 to 0.1, e* is in the range of 0.01 to 0.2, preferably 0.015 to 0.04, d* is in the range of 0 to 0.1, preferably 0 to 0.02; M 2 is at least one of W, Mo, Ti or Zr).

[0017] The variable x ranges from -0.05 to 0.2.

[0018] In one embodiment of the present invention, TM corresponds to general formula (Ia), where x is in the range of -0.05 to 0.2, preferably 0 to 0.1, and even more preferably 0.01 to 0.05.

[0019] In one embodiment of the present invention, TM corresponds to general formula (Ib), where x is in the range of -0.05 to 0.

[0020] The electrode active material provided in step (a) generally does not contain conductive carbon, i.e., the conductive carbon content of the starting material is less than 1% by mass, preferably 0.001 to 1.0% by mass, based on the starting material.

[0021] Some elements are ubiquitous. In the context of the present invention, trace amounts of ubiquitous metals, such as sodium, calcium, iron or zinc, as impurities are not considered in the context of the present invention. Trace amounts in this context mean amounts of 0.02 mol % or less, relative to the total metal content of the starting material.

[0022] In step (b), the electrode active material provided in step (a) is treated with an aqueous medium, preferably water. The aqueous medium has a pH value in the range of 2 to 14, preferably at least 3.5, more preferably 5 to 7. The pH value is measured at the start of step (b). During the course of step (b), the pH value is observed to increase to at least 10, for example, 11 to 13. In embodiments where the pH value is in the range of 10 to 11 at the start of step (b), the pH value increases to greater than 11 to 13. In embodiments where the pH value is in the range of 3 to less than 10 at the start of step (b), the pH value increases to 11 to 13 during the course of step (b).

[0023] Preferably, the hardness, especially calcium, of the aqueous medium used in step (b) is at least partially removed. The use of demineralized water is preferred.

[0024] In one embodiment of step (b), the aqueous medium used in step (b) may further contain ammonia or at least one transition metal salt, such as a nickel salt or a cobalt salt. Such transition metal salts preferably have counterions that are not harmful to the electrode active material. Sulfates and nitrates can be used. Chlorides are not preferred. However, it is preferred to treat the electrode active material provided in step (a) with water containing no additives.

[0025] In one embodiment of the present invention, step (b) is carried out at a temperature in the range of 5 to 85°C, preferably 10 to 60°C.

[0026] In one embodiment of the invention, step (b) is carried out at atmospheric pressure. However, it is preferred to carry out step (b) under elevated pressure, for example at a pressure of 10 mbar to 10 bar above atmospheric pressure, or under vacuum, for example at a pressure of 50 to 250 mbar below atmospheric pressure, preferably at a pressure of 100 to 200 mbar below atmospheric pressure.

[0027] For example, step (b) may be carried out in a vessel that is easily drained, e.g., located above a filter device. Such a vessel may be filled with the starting material, followed by the introduction of the aqueous medium. In other embodiments, such a vessel is filled with the aqueous medium, followed by the introduction of the starting material. In other embodiments, the starting material and the aqueous medium are introduced simultaneously.

[0028] In one embodiment of the present invention, the volume ratio of the electrode active material to the total aqueous medium in step (b) is in the range of 2:1 to 1:5, preferably 2:1 to 1:2.

[0029] In one embodiment of the present invention, the mass ratio of water to the electrode active material in step (b) is in the range of 5:1 to 1:20, preferably 1:5 to 1:20, and even more preferably 5:1 to 1:5.

[0030] Step (b) is supported by a mixing operation, such as shaking, or especially stirring or shearing (see below).

[0031] In one embodiment of the invention, step (b) has a duration ranging from 1 minute to 30 minutes, preferably from 1 minute to less than 5 minutes. In embodiments in which water treatment and water removal are performed in overlapping or simultaneous steps (b), durations of 5 minutes or more are possible.

[0032] In one embodiment of the present invention, the treatment according to step (b) and the water removal according to step (c) are carried out sequentially.

[0033] After or during the treatment with aqueous medium according to step (b), the water can be removed by any type of filtration, for example in a band filter or filter press.

[0034] In one embodiment of the invention, step (c) is initiated at the latest 3 minutes after the start of step (b), and step (c) comprises removing water from the treated particulate matter, for example by solid-liquid separation, for example by decantation, or preferably by filtration.

[0035] In one embodiment of step (c), the slurry obtained in step (b) is discharged into a centrifuge, such as a decanter centrifuge or a filter centrifuge, or into a filter device, such as a suction filter, or preferably directly into a belt filter located directly below the vessel in which step (b) is carried out, after which filtration begins.

[0036] In a particularly preferred embodiment of the present invention, steps (b) and (c) are carried out in a filter device equipped with an agitator, such as a pressure filter equipped with an agitator or a suction filter equipped with an agitator. After combining the starting material and the aqueous medium according to step (b), removal of the aqueous medium is initiated by starting filtration up to 3 minutes later, or even immediately thereafter. On a laboratory scale, steps (b) and (c) are carried out in a Buchner funnel, and steps (b) and (c) are supported by manual agitation.

[0037] In a preferred embodiment, step (b) is carried out in a filter apparatus, such as an agitated filter apparatus, which allows for agitation of the slurry or filter cake in the filter.

[0038] In one embodiment of the present invention, the water removal according to step (c) has a duration ranging from 1 minute to 1 hour.

[0039] In one embodiment of the present invention, stirring in step (b), and, where applicable, step (c), is carried out at a speed in the range of 1 to 50 revolutions per minute ("rpm"), with 5 to 20 rpm being preferred.

[0040] In one embodiment of the present invention, the filter media can be selected from ceramic, sintered glass, sintered metal, organic polymer film, nonwoven fabric, and woven fabric.

[0041] In one embodiment of the present invention, steps (b) and (c) are carried out in an atmosphere having a reduced CO content, for example, a carbon dioxide content in the range of 0.01 to 500 ppm by mass, with 0.1 to 50 ppm by mass being preferred. The CO content can be determined, for example, by an optical method using infrared light. It is even more preferred to carry out steps (b) and (c) in an atmosphere having a carbon dioxide content below the detection limit of, for example, an optical method based on infrared light.

[0042] From step (c), a residue is preferably obtained in the form of a wet filter cake, the moisture content of which may range from 3 to 20% by weight, preferably from 4 to 9% by weight.

[0043] In step (d), the residue from step (c) is treated with a compound of Me, wherein Me is selected from at least one of aluminum, antimony, boron, phosphorus, molybdenum, vanadium, and tellurium. The compound may be added in bulk or as an aqueous formulation. Examples of aqueous formulations include solutions, slurries, and colloidal solutions. The compound of Me, wherein Me is selected from aluminum, antimony, boron, phosphorus, molybdenum, vanadium, and tellurium, is hereinafter also referred to as "a compound of Me" or "Me compound."

[0044] The aqueous formulation has a pH value in the range of 2-14, preferably at least 3.5, more preferably 5-11.

[0045] In one embodiment of the present invention, the pH value of the aqueous formulation used in step (d) is controlled by the addition of a basic Li compound, in particular LiOH.

[0046] The pH value is measured at the start of step (d). Depending on the order of addition of the electrode active material, water, and Me compound, it is observed that the pH value may increase to at least 10, e.g., 11 to 13, during the course of step (d). In embodiments where the pH value is in the range of 10 to 11 at the start of step (d), it increases to greater than 11 to 13. In embodiments where the pH value is in the range of 3 to less than 10 at the start of step (d), it increases to 11 to 13. It is preferred that the water hardness, especially calcium, of the aqueous formulation used in step (d) is at least partially removed. The use of demineralized water is preferred.

[0047] Among the compounds of Me, inorganic compounds of Me are preferred.

[0048] Of the inorganic compounds of Me, the oxides, hydroxides, sulfates, and lithiated oxides are preferred, although water-soluble halides such as chlorides can also be used.

[0049] The inorganic compounds of Me may be readily soluble in water. "Water soluble" in this context means a solubility of at least 10 g of the respective metal per liter of water at 25°C.

[0050] In another embodiment, the inorganic compound of Me is water-insoluble. "Water-insoluble" in this context means an aluminum compound with a solubility of less than 0.1 g per liter of water at 25° C. Examples include Al2O3, Al(OH)3, AlOOH, and Al2O3·aq, with AlOOH and Al2O3 being preferred.

[0051] The water-insoluble compound of Me may be dispersed or slurried in water. In the context of the present invention, AlOOH may also be referred to as Al(O)(OH), not necessarily having equimolar amounts of oxide and hydroxide.

[0052] In one embodiment of the invention, the compound of Me is a compound of aluminum, in particular an inorganic compound of aluminum. The inorganic compounds of aluminum used in step (d), in particular Al2O3 and Al(O)(OH), may be pure (≥ 99.9 mol% Al, based on the sum of the metals, including Si) or may be doped with oxides, such as La2O3, Ce2O3, titania or zirconia, for example in an amount of 0.1 to 5 mol%.

[0053] In one embodiment of the present invention, the water-insoluble compound of Me is dispersed in water and has an average particle size (D50) determined by X-ray diffraction in the range of 200 nm to 5 μm, preferably 2 to 5 μm.

[0054] In one embodiment of the present invention, the Me compound is provided as a colloidal preparation ("colloidal solution"). AlOOH is preferably used as the colloidal solution, and its average particle size, determined from the full width at half maximum ("FWMH") of the reflections detected in the X-ray diffraction pattern, is preferably in the range of 5 to 10 nm. Such particles in the colloidal solution may form aggregates with an average particle size in the range of 20 to 200 nm, preferably 20 to 50 nm. Such colloidal solutions preferably have a pH value in the range of 5 to 6. As a dry powder, aggregates with an average particle size of up to 15 μm can be formed.

[0055] Examples of antimony compounds include Sb(III) compounds and Sb(V) compounds. Examples of Sb(III) compounds include Sb(OH), SbO·aq, Sb(SO), SbOOH, LiSbO, and SbO. Examples of Sb(V) compounds include SbO, LiSbO, LiSbO, LiSbO, LiSbO, LiSbO, LiSbO, LiSbO, LiSbO, LiSbO, SbO, (Sb(III)Sb(V)O), and Sb(V) oxyhydroxides such as, but not limited to, SbO(OH), SbO(OH), SbO(OH), SbOOH, and SbOOH.

[0056] Examples of boron compounds include, but are not limited to, boric acid, B2O3, Li3BO3, LiBO2, and lithium polyborates such as, but not limited to, Li2B4O7. Examples of vanadium compounds include V2O5 and LiVO3. Examples of molybdenum compounds include MoO3 and Li2MoO4.

[0057] Examples of phosphorus compounds include "P2O5" (P4O 10 ), LiPO3, Li3PO4, and preferably lithium hydrogen phosphate, e.g., LiH2PO4, Li2HPO4, and mixtures, e.g., Li 1.5 H 1.5 PO4 and Li 1.16 H 1.84 PO4 is an example.

[0058] Examples of compounds of Te include TeO2, TeO3, and Li2TeO3.

[0059] In one embodiment of the present invention, the water-insoluble compound of Me is dispersed in water and has an average particle size (D50) determined by scanning electron microscopy (SEM) in the range of 200 nm to 10 μm, preferably 2 to 5 μm.

[0060] In one embodiment, the compound of Me is added in bulk.

[0061] In a preferred embodiment, the compound of Me is water soluble and is added in an aqueous solution, in particular an aqueous solution further containing LiOH.

[0062] In one embodiment, the amount of the Me compound is in the range of 0.01 to 3.0 mol %, preferably 0.1 to 1.0 mol %, relative to TM.

[0063] In one embodiment of step (d), the compound of Me in step (d) is selected from Al2O3, Sb2O3, Li2TeO3, SnO2, SnO, or a combination of at least two of the foregoing dispersed in water.

[0064] The treating in step (d) can be carried out by adding a compound of Me to the water-containing residue of step (c) and allowing the resulting mixture to interact, which may be facilitated by stirring.

[0065] In one embodiment of the present invention, step (d) is carried out at a temperature in the range of 5 to 85° C., preferably 10 to 60° C. Room temperature is particularly preferred.

[0066] In one embodiment of the invention, step (d) is carried out at atmospheric pressure. However, it is preferred to carry out step (d) under elevated pressure, for example at a pressure of 10 mbar to 10 bar above atmospheric pressure, or under vacuum, for example at a pressure of 50 to 250 mbar below atmospheric pressure, preferably at a pressure of 100 to 200 mbar below atmospheric pressure.

[0067] In one embodiment of the invention, step (d) is carried out in a filter device equipped with an agitator, such as a pressure filter equipped with an agitator or a suction filter equipped with an agitator.

[0068] The time for treating the residue in step (c) with the compound of Me may range from 2 to 30 minutes.

[0069] In one embodiment of the present invention, steps (b) to (d) are carried out in the same vessel, for example in a filter device equipped with an agitator, such as a pressure filter equipped with an agitator or a suction filter equipped with an agitator.

[0070] The method of the present invention comprises the following step (e): (e) heat treating the material resulting from step (d).

[0071] Step (e) can be carried out in any type of oven, such as a roller hearth kiln, a pusher kiln, a rotary kiln, a pendulum kiln, or in the case of laboratory scale tests, a muffle oven.

[0072] The temperature of the heat treatment in step (e) may be in the range of 300 to 900°C, preferably 300 to 700°C, and even more preferably 550 to 650°C.

[0073] The temperature of 350 to 700°C corresponds to the maximum temperature in step (e).

[0074] The material obtained from step (d) can be subjected directly to step (e). However, it is preferred to increase the temperature stepwise or gradually, or to first dry the material obtained after step (d) at a temperature in the range of 40-80°C before subjecting it to step (e), or to remove the water by solid-liquid separation, for example, filtration.

[0075] The stepwise or gradual increase can be carried out under normal pressure or reduced pressure, for example, at a pressure of 1 to 500 mbar.

[0076] Step (e) at the highest temperature is carried out under atmospheric pressure.

[0077] In one embodiment of the present invention, step (e) is carried out under an oxygen-containing atmosphere, such as air, oxygen-enriched air or pure oxygen.

[0078] In embodiments where step (e) is preceded by drying at a temperature in the range of 100 to 250° C., such drying is carried out for a duration of 10 minutes to 5 hours.

[0079] In one embodiment of the present invention, step (e) is carried out in an atmosphere having a reduced CO content, for example, a carbon dioxide content in the range of 0.01 to 500 ppm by mass, with 0.1 to 50 ppm by mass being preferred. The CO content can be determined, for example, by an optical method using infrared light. It is even more preferred to carry out step (e) in an atmosphere having a carbon dioxide content below the detection limit of an optical method based on infrared light.

[0080] In one embodiment of the present invention, step (e) has a duration ranging from 1 to 10 hours, preferably from 90 minutes to 6 hours.

[0081] In one embodiment of the present invention, the lithium content of the electrode active material is reduced by 1 to 5 mass %, preferably 2 to 4 mass %, which mainly affects the so-called residual lithium.

[0082] By carrying out the method of the present invention, an electrode active material having excellent electrochemical properties can be obtained. Without wishing to be bound by any theory, it is hypothesized that the excess Me compounds lead to the removal of lithium compounds deposited on the surface of the electrode active material.

[0083] Without wishing to be bound by any theory, it is hypothesized that the surface of the electrode active material is less adversely affected by the method of the present invention than by cleaning methods that do not add Me compounds.

[0084] A further aspect of the present invention relates to an electrode active material, hereinafter also referred to as the electrode active material of the present invention. The electrode active material of the present invention is in particulate form and has the general formula Li 1+x1 TM 1-x1O2 (wherein TM is a combination of Ni, Co, and optionally Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, and x is in the range of -0.05 to 0), wherein the particles are aggregates of primary particles, at least 60 mol % of the transition metal in TM is Ni, and a combination of oxides of Me', where Me' is selected from antimony, molybdenum, vanadium, and tellurium, and lithium oxide species of Me' are uniformly distributed among the primary particles.

[0085] In a preferred embodiment of the invention, Me' is Al or Sb or Te, with Te being particularly preferred.

[0086] In one embodiment of the present invention, the lithiated oxide of Me', such as LiSbO2 or Li2TeO3, is amorphous.

[0087] In one embodiment of the invention, the outer surface of the particle is uniformly coated with a combination of oxide of antimony and lithium oxide of antimony species, the coating being uniform as detected by EDX mapping ("energy dispersive X-ray mapping").

[0088] Such coatings are uniform, i.e., in TEM, the Me' oxide and lithium Me' oxide species appear to be uniformly distributed on the surface of the primary and secondary particles.

[0089] In one embodiment of the invention, the variable TM corresponds to the general formula (Ia) (Ni a Co b Mn c ) 1-d M 1 d (I a) (wherein a+b+c=1, a is in the range of 0.75 to 0.95, preferably 0.85 to 0.95; b is in the range of 0.025 to 0.2, preferably 0.025 to 0.1, c is in the range of 0.025 to 0.2, preferably 0.05 to 0.1, d is in the range of 0 to 0.1, preferably 0 to 0.04; M 1 is at least one of Al, Mg, W, Mo, Ti or Zr, preferably at least one of Al, Ti and W).

[0090] In one embodiment of the present invention, the variable c is zero and M 1 is Al and d is in the range of 0.01 to 0.05.

[0091] In another embodiment of the invention, the variable TM corresponds to the general formula (Ib) (Ni a* Co b* Al e* ) 1-d* M 2 d* (I b) (wherein a*+b*+c*=1, a* is in the range of 0.75 to 0.95, preferably 0.88 to 0.95; b* is in the range of 0.025 to 0.2, preferably 0.025 to 0.1, e* is in the range of 0.01 to 0.2, preferably 0.015 to 0.04, d* is in the range of 0 to 0.1, preferably 0 to 0.02; M 2 is at least one of W, Mo, Ti or Zr).

[0092] The variable x1 ranges from -0.05 to 0.15.

[0093] In one embodiment of the present invention, TM corresponds to general formula (Ia), where x ranges from 0 to 0.2, preferably from 0 to 0.1, and even more preferably from 0.01 to 0.05.

[0094] In one embodiment of the present invention, TM corresponds to general formula (Ib), where x is in the range of -0.05 to 0.

[0095] In one embodiment of the present invention, the electrode active material of the present invention has an average particle size (D50) in the range of 3 to 20 μm, preferably 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of aggregates of primary particles, and the above particle size refers to the particle size of secondary particles.

[0096] In one embodiment of the present invention, the electrode active material of the present invention has a viscosity of 0.1 to 2.0 m 2 / g, determined according to DIN-ISO 9277:2003-05.

[0097] A further aspect of the present invention relates to electrodes comprising at least one electrode active material according to the present invention. They are particularly useful in lithium-ion batteries. Lithium-ion batteries comprising at least one electrode according to the present invention exhibit good discharge behavior. An electrode comprising at least one electrode active material according to the present invention is hereinafter also referred to as a cathode according to the present invention or a cathode according to the present invention.

[0098] The cathode according to the present invention may contain additional components, such as, but not limited to, a current collector, such as aluminum foil, and may further contain conductive carbon and a binder.

[0099] Suitable binders are 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 (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 furthermore suitable. Polyacrylonitrile is particularly preferred.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] Another preferred binder is polybutadiene.

[0105] Other suitable binders are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

[0106] 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:

[0107] The binder may be a crosslinked or non-crosslinked (co)polymer.

[0108] In a particularly preferred embodiment of the present invention, the binder 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.

[0109] Suitable binders are, in particular, 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.

[0110] The cathode of the present invention may contain 1 to 15% by weight of binder(s) relative to the electrode active material. In other embodiments, the cathode of the present invention may contain 0.1% to less than 1% by weight of binder(s).

[0111] A further aspect of the invention is a battery containing at least one cathode comprising the electrode active material of the invention, carbon and a binder, at least one anode, and at least one electrolyte.

[0112] The cathode embodiment of the present invention has already been described in detail above.

[0113] The anode may contain at least one anode active material such as carbon (graphite), TiO, lithium titanium oxide, silicon, or tin. The anode may further contain a current collector, for example, a metal foil such as copper foil.

[0114] The electrolyte may include at least one non-aqueous solvent, at least one electrolyte salt, and optionally, additives.

[0115] The non-aqueous solvent for the electrolyte 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.

[0116] Examples of suitable polymers are, in particular, polyalkylene glycols, preferably poly-C1-C4-alkylene glycols, and especially polyethylene glycols, where the polyethylene glycols may contain up to 20 mol % of one or more C1-C4-alkylene glycols. The polyalkylene glycols are preferably polyalkylene glycols with two methyl or ethyl end caps.

[0117] The molecular weight M of suitable polyalkylene glycols, especially suitable polyethylene glycols, W may be at least 400 g / mol.

[0118] The molecular weight M of suitable polyalkylene glycols, especially suitable polyethylene glycols, W can be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol.

[0119] Examples of suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, with 1,2-dimethoxyethane being preferred.

[0120] Examples of suitable cyclic ethers are tetrahydrofuran and 1,4-dioxane.

[0121] Examples of suitable acyclic acetals are, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane and 1,1-diethoxyethane.

[0122] An example of a suitable cyclic acetal is 1,3-dioxane, and especially 1,3-dioxolane.

[0123] Examples of suitable acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.

[0124] Examples of suitable cyclic organic carbonates are those of the general formulae (II) and (III):

[0125] [ka]

[0126] (In the formula, R 1 , R 2 and R 3 can be the same or different and are selected from hydrogen and C1-C4-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, preferably R 2 and R 3 (Both cannot be tert-butyl) It is a compound according to

[0127] In a particularly preferred embodiment, R 1 is methyl and R 2 and R 3 are each hydrogen or R 1 , R 2 and R 3 are hydrogen atoms.

[0128] Another preferred cyclic organic carbonate is vinylene carbonate of formula (IV).

[0129] [ka]

[0130] Preferably, the solvent or solvents are used in an anhydrous state, ie with a water content in the range of 1 ppm to 0.1% by weight, which can be determined, for example, by Karl Fischer titration.

[0131] The electrolyte (C) further comprises at least one electrolyte salt. Suitable electrolyte salts are, in particular, lithium salts. Examples of suitable lithium salts are LiPF, LiBF, LiClO, LiAsF, LiCF, SO, LiC(C n F 2n+1 SO2)3, lithium imide, e.g., LiN(C n F 2n+1 SO2)2 (wherein n is an integer ranging from 1 to 20), LiN(SO2F)2, Li2SiF6, LiSbF6, LiAlCl4, and compounds of the general formula (C n F 2n+1 SO2) t YLi salt wherein t=1 when Y is selected from oxygen and sulfur; when Y is selected from nitrogen and phosphorus, t=2; When Y is selected from carbon and silicon, t=3).

[0132] Preferred electrolyte salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred.

[0133] In an embodiment of the present invention, the battery according to the present invention includes one or more separators by which the electrodes are mechanically separated. Preferred separators are polymer films, particularly porous polymer films, that are unreactive with metallic lithium. Particularly preferred materials for the separator are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0134] 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.

[0135] In another embodiment of the present invention, the separator can be selected from PET nonwoven fabrics filled with inorganic particles. Such separators can have a porosity in the range of 40 to 55%. Suitable pore sizes are, for example, in the range of 80 to 750 nm.

[0136] The battery according to the invention further comprises a housing which may have any shape, for example a cube, or the shape of a cylindrical disk or a cylindrical can. In one variant, a metal foil configured as a pouch is used as the housing.

[0137] The battery according to the invention exhibits eg good discharge behaviour at low temperatures (below 0° C., even below −10° C.), very good discharge and cycling behaviour.

[0138] The battery according to the present invention may comprise two or more electrochemical cells that are combined with one another, for example, connected in series or in parallel. A series connection is preferred. In the battery according to the present invention, at least one electrochemical cell contains at least one cathode according to the present invention. Preferably, in the electrochemical cell according to the present invention, the majority of the electrochemical cells contain cathodes according to the present invention. Even more preferably, in the battery according to the present invention, all electrochemical cells contain cathodes according to the present invention.

[0139] The present invention further provides a method for using the battery according to the present invention in a device, in particular a mobile device. Examples of mobile devices are vehicles, such as automobiles, bicycles, aircraft, or water vehicles, such as boats or ships. Other examples of mobile devices are manually operated devices, such as computers, in particular laptops, telephones, or powered hand tools, for example in the construction sector, in particular drills, battery-powered screwdrivers, or battery-powered staplers.

[0140] The present invention is further illustrated by the following examples. [Example]

[0141] Review: N-methyl-2-pyrrolidone: NMP.

[0142] I. Synthesis of Cathode Active Material I.1 Synthesis of precursor TM-OH.1 A stirred tank reactor was charged with deionized water and 49 g of ammonium sulfate per kg of water. The solution was heated to 55° C. and the pH was adjusted to 12 by adding aqueous sodium hydroxide.

[0143] 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 and a residence time of 8 hours. The transition metal solution contained Ni, Co, and Mn in a molar ratio of 8.5:1.0:0.5 and a total transition metal concentration of 1.65 mol / kg. The aqueous sodium hydroxide solution was a 25 wt.% sodium hydroxide solution and a 25 wt.% 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 a mixed transition metal (TM) oxyhydroxide precursor.

[0144] I.2 Conversion of TM-OH.1 into cathode active material I.2.1 Preparation of Comparative Cathode Active Material C-CAM.1, Step (a.1) C-CAM.1 (comparison): The mixed transition metal oxyhydroxide precursor obtained according to I.1 was mixed with Al2O3 (average particle size 6 nm) to obtain a concentration of Al of 0.3 mol% relative to Ni+Co+Mn+Al and a Li / (TM+Al) molar ratio of 1.06. The mixture was heated to 760 °C and kept for 10 hours in a forced flow of a mixture of 60 vol% oxygen and 40 vol% nitrogen. After cooling to room temperature, the powder was deagglomerated and sieved through a 32 μm mesh to obtain the electrode active material C-CAM 1.

[0145] The D50 determined using laser diffraction techniques on a Mastersize 3000 machine from Malvern Instruments was 9.0 μm. The Al content was determined by ICP analysis and corresponded to 780 ppm. The residual moisture determined at 250 °C was 300 ppm.

[0146] I.2.2 Treatment with Li2TeO3 in the presence of water Step (b.1): 67 ml of deionized water was placed in a flask. A 100 g amount of C-CAM.1 was added. The resulting slurry was stirred at room temperature for 5 minutes.

[0147] Step (c.1): Next, the water was removed by filtration through a filter press.

[0148] Step (d.1): 4.5 g of Li2TeO3 aq was added to the filter cake. The molar ratio of Te / (TM + Te) was 0.003. The filter cake containing Li2TeO3 aq was placed in a plastic bag and scrambled at room temperature for 5 minutes.

[0149] Step (e.1): The obtained filter cake was dried in ultra-dry air at 70°C for 2 hours, then at 120°C for 10 hours, and then heat-treated in an oxygen atmosphere at 700°C for 1 hour.

[0150] The resulting powder was then sieved through a 45 μm sieve to obtain a cathode active material CAM.2 of the present invention.

[0151] By changing the type and amount of Me compound, additional cathode active materials of the present invention were fabricated accordingly, and the results are summarized in Table 1.

[0152] II. Cathode Active Material Testing II.1 Electrode fabrication, general procedure II.1.1 Cathode fabrication Positive electrode: PVDF binder (Solef® 5130) was dissolved in NMP (Merck) to prepare a 7.5 wt% solution. For electrode preparation, the binder solution (3 wt%), graphite (SFG6L, 2 wt%), and carbon black (Super C65, 1 wt%) were suspended in NMP. After mixing using a planetary mixer (ARE-250, Thinky Corp., Japan), the cathode active material (94 wt%) of the present invention (CAM.1 to CAM.7) or the comparative cathode active material was added, and the suspension was mixed 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 thickness of the cathode material was 70 μm, with a coating weight of 15 mg / cm. 2 Before assembling the battery, all electrodes were dried at 105°C for 7 hours.

[0153] II.1.2: Fabrication of pouch cell anode Graphite and carbon black were thoroughly mixed. A CMC (carboxymethyl cellulose) aqueous solution and an SBR (styrene butadiene rubber) aqueous solution were used as binders. The electrode active material, carbon (a mixture of graphite and carbon black):CMC:SBR in a mass ratio of 96:0.5:2:1.5, was mixed with the binder solution, and a sufficient amount of water was added to prepare a slurry suitable for electrode preparation. The resulting slurry was coated onto copper foil (thickness = 10 μm) using a roll coater and dried at room temperature. In the single-layer pouch cell test, the mass gain of the electrode sample on the copper foil was 10 mg cm. -2 Fixed to.

[0154] II.2: Electrolyte Preparation A base electrolyte composition (EL Base 1) was prepared containing 12.7 wt. % LiPF, 26.2 wt. % ethylene carbonate (EC), and 61.1 wt. % ethyl methyl carbonate (EMC), based on the total weight of EL Base 1. 2 wt. % vinylene carbonate (VC) was added to this base electrolyte formulation (EL Base 2).

[0155] II.3 Test cell construction II.3.1 Coin-shaped half-cell Coin-shaped half-cells (20 mm diameter, 3.2 mm thickness) containing the cathode prepared as described in Section III.1.1 and lithium metal as the working and counter electrodes were assembled and sealed in an Ar-filled glove box. The cathode, anode, and separator were stacked in the order cathode / separator / Li foil to fabricate half-coin cells. Then, 0.15 mL of the EL base 1 described above (III.2) was introduced into the coin cells.

[0156] II.3.2 Pouch Cell A single-layer pouch cell (70 mA h) containing the anode prepared as described in III.1.1 and the graphite electrode prepared in III.1.2 was assembled and sealed in an Ar-filled glove box. A multi-layer pouch cell was fabricated by stacking the cathode, anode, and separator in the order cathode / separator / anode. Then, 0.8 mL of the electrolyte EL Base 2 was introduced into the laminated pouch cell.

[0157] III. Cell performance evaluation Evaluation of coin half-cell performance The cell performance of the manufactured coin-type battery was evaluated by measuring the initial capacity and reaction resistance of the cell.

[0158] Initial performance and cycling were measured as follows: The coin half-cells according to II.3.1 were tested at room temperature over a voltage range of 4.3 V to 2.8 V. For the initial cycle, initial lithiation was performed in CC-CV mode, i.e., a constant current (CC) of 0.1 C was applied until 0.01 V was reached. After a 10-minute rest period, reduction lithiation was performed at a constant current from 0.1 C to 2.8 V. For cycling, the current density was 0.1 C. The results are summarized in Table 2.

[0159] The cell reaction resistance was calculated as follows: After initial performance evaluation, the coin cells were recharged to 4.3 V, and the resistance was measured by the AC impedance method using a potentiostat and frequency response analyzer system (Solartron CellTest System 1470E). From the EIS spectrum, the ohmic resistance and relative resistance can be determined. The results are summarized in Table 1. The [%] relative resistance is based on the resistance of the C-CAM.1-based cell as 100%.

[0160] [Table 1]

[0161] wrt: CAM.20: pH was 7.

[0162] [Table 2]

Claims

1. The following steps: (a) General formula Li １＋ｘ TM １－ｘ O ２ providing an electrode active material according to the formula: wherein TM is Ni, and optionally at least one of Co and Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, x is in the range of −0.05 to 0.2, and at least 50 mol % of the transition metals in TM are Ni; (b) mixing the electrode active material in an aqueous medium; (c) partially removing the water by solid-liquid separation; (d) stirring the residue with a compound of Me, wherein the compound of Me is selected from Al 2 O 3 , Sb 2 O 3 , Li 2 TeO 3 , or a combination of at least two of the foregoing, dispersed in water; (e) thermally treating the residue; and TM is a compound represented by the general formula (I) (Ni a Co b Mr c ) 1-d M d (I) (wherein a is in the range of 0.75 to 0.95; b is in the range of 0.025 to 0.2; c is in the range of 0.025 to 0.2; d is in the range of 0 to 0.1; M is at least one of Al, Mg, Ti, Mo, W, and Zr; a + b + c = 1) A method for producing a partially coated electrode active material, which is a combination of metals according to the method of claim 1.

2. The method of claim 1 wherein M is Al.

3. 3. The method according to claim 1 or 2, wherein step (c) is carried out by filtration or with the aid of a centrifuge.

4. 4. The method according to claim 1, wherein the aqueous medium in step (b) is water.

5. 5. The method according to any one of claims 1 to 4, wherein a moist filter cake is obtained from step (c).

6. 6. The method of any one of claims 1 to 5, wherein step (e) comprises a calcination step at a maximum temperature in the range of from 300 to 700°C.

7. 6. The method of any one of claims 1 to 5, wherein step (e) comprises a drying step at a maximum temperature in the range of from 40 to 250°C.

8. The following steps: (a) General formula Li １＋ｘ TM １－ｘ O ２ providing an electrode active material according to the formula: wherein TM is Ni, and optionally at least one of Co and Mn, and optionally at least one element selected from Al, Mg, Ba, and B, and transition metals other than Ni, Co, and Mn, x is in the range of −0.05 to 0.2, and at least 50 mol % of the transition metals in TM are Ni; (b) mixing the electrode active material in an aqueous medium; (c) partially removing the water by solid-liquid separation; (d) stirring the residue with a compound of Me, wherein the compound of Me is selected from Al 2 O 3 , Sb 2 O 3 , Li 2 TeO 3 , or a combination of at least two of the foregoing, dispersed in water; (e) thermally treating the residue; and TM is Ni ０．６ Co ０．２ Mn ０．２ , Ni ０．７ Co ０．２ Mn ０．１ , Ni ０．８ Co ０．１ Mn ０．１ , Ni ０．８８ Co ０．０５５ Al ０．０５５ , Ni ０．９ Co ０．０４５ Al ０．０４５ and Ni ０．８５ Co ０．１ Mn ０．０５ A method selected from the following.

9. 9. The method according to any one of claims 1 to 8, wherein in step (b), the mass ratio of water to electrode active material is in the range of 1:5 to 1:

20.

10. General formula Li １＋ｘ１ TM １－ｘ１ O ２ wherein TM is a combination of Ni, Co, optionally Mn, and optionally Al, Mg, Ba, and B, and at least one element selected from transition metals other than Ni, Co, and Mn, and x1 is in the range of −0.05 to 0.15; the particles are aggregates of primary particles, at least 60 mol % of the transition metal of TM is Ni, and a combination of oxides of Me′ and lithium oxide species of Me′ is uniformly distributed among the primary particles, and Me′ is selected from antimony and tellurium; and The particulate electrode active material has a surface that has been treated in a washing step during its production process, at a stage where no heat treatment is performed, in which the surface is washed with a compound of Me selected from Al 2 O 3 , Sb 2 O 3 , Li 2 TeO 3 , or a combination of at least two of the above and dispersed in water.

11. 11. The particulate electrode active material of claim 10, wherein the outer surface of the particles is uniformly coated with a combination of oxide of tellurium and lithium oxide species of tellurium, the coating being uniform as detected by EDX mapping.

12. TM is a compound represented by the general formula (I) (Ni a Co b Mr c ) 1-d M d (I) (wherein a is in the range of 0.75 to 0.95; b is in the range of 0.025 to 0.2; c is in the range of 0.025 to 0.2; d is in the range of 0 to 0.1; M is at least one of Al, Mg, Ti, Mo, W, and Zr; a + b + c = 1) 12. The particulate electrode active material according to claim 10, wherein the metal combination is selected from the group consisting of:

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