Method for producing manganese-rich cathode active material

Abstract

Formula Li 1+x TM 1-x TM is a compound represented by the general formula (I): (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38, b ranges from zero to 0.05, c is in the range of 0.60 to 0.70, d ranges from zero to 0.05, M 1 is selected from Al, Ti, Zr, W, Mo, Nb, Ta, Mg, and a combination of at least two of the above; a+b+c=1) is a combination of elements by The method comprises the steps of: (a) manganese, nickel, and optionally Co and M 1 providing a particulate hydroxide, oxide or oxyhydroxide with at least one of (b) adding a lithium source; (c) firing the mixture obtained from step (b) at a maximum temperature in the range of 650 to 1000°C in an atmosphere containing 0.05 to 5% by volume of oxygen; Includes:

Description

[Technical Field]

[0001] The present invention relates to a compound of formula Li 1+x TM 1-x and TM is a compound of the general formula (I): (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38, b ranges from zero to 0.05, c is in the range of 0.60 to 0.70, d ranges from zero to 0.05, M 1 is selected from Al, Ti, Zr, W, Mo, Nb, Ta, Mg, and a combination of at least two of the above; a+b+c=1) It is a combination of elements by The method comprises the steps of: (a) manganese, nickel, and optionally Co and M 1 providing a particulate hydroxide, oxide or oxyhydroxide with at least one of (b) adding a lithium source; (c) firing the mixture obtained from step (b) at a maximum temperature in the range of 650 to 1000°C in an atmosphere containing 0.05 to 5% by volume of oxygen; Includes: [Background technology]

[0002] Lithiated transition metal oxides are currently used as electrode active materials in lithium-ion batteries. Extensive research and development has been conducted over the past several years to improve properties such as charge density and specific energy, as well as other properties such as cycle life degradation and capacity loss that adversely affect the life or applicability of lithium-ion batteries. Further efforts are being made to improve manufacturing methods.

[0003] Many of the electrode active materials currently under discussion are of the lithiated nickel-cobalt-manganese oxide ("NCM material") or lithiated nickel-cobalt-aluminum oxide ("NCA material") type.

[0004] In a typical process for preparing cathode materials for lithium-ion batteries, a transition metal is first co-precipitated as a carbonate, oxide, or preferably as a hydroxide, which may or may not be basic, to form a so-called precursor. This precursor is then mixed with a lithium salt, such as, but not limited to, LiOH, Li2O, or especially Li2CO3, and calcined at high temperatures. The lithium salt(s) can be used as hydrate(s) or in dehydrated form. Calcination or calcination, also commonly referred to as thermal treatment or heat treatment of the precursor, is typically carried out at temperatures ranging from 600 to 1000°C. During the heat treatment, a solid-state reaction occurs to form the electrode active material. When hydroxides or carbonates are used as precursors, water or carbon dioxide is removed after the solid-state reaction. The heat treatment is carried out in the heated zone of an oven or kiln.

[0005] Many studies have been conducted to improve various properties of cathode active materials, such as energy density and charge-discharge performance, including capacity fade. However, many cathode active materials suffer from limited cycle life and voltage fade. This is especially true for many Mn-rich cathode active materials.

[0006] Certain high manganese materials with high energy density retention are disclosed in EP 3 486 980. However, the disclosed cathode active materials themselves suffer from limited energy density. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] EP 3 486 980 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention was to provide a method for producing a cathode active material having both a high energy density and a high energy density retention.A further object of the present invention was to provide a cathode active material having both a high energy density and a high energy density retention.A further object of the present invention was to provide a use of a cathode active material having both a high energy density and a high energy density retention. [Means for solving the problem]

[0009] Thus, a method as defined at the outset has been found, hereinafter also referred to as "the method of the invention", which comprises the following steps: (a) manganese, nickel, and optionally Co and M 1 providing a particulate hydroxide, oxide or oxyhydroxide with at least one element of M 1 is selected from Al, Ti, Zr, W, Mo, Mg, B, and combinations of at least two of the foregoing; (b) adding a lithium source; (c) firing the mixture obtained from step (b) at a maximum temperature in the range of 650 to 1000°C in an atmosphere containing 0.05 to 5% by volume of oxygen; Includes: DETAILED DESCRIPTION OF THE INVENTION

[0010] The method of the present invention comprises three steps (a), (b) and (c), which in the context of the present invention are also referred to hereinafter as step (a), step (b) and step (c), respectively. Each step will now be described in more detail.

[0011] In step (a), manganese, nickel, and optionally Co and M 1 The precursor is provided with a particulate hydroxide, oxide or oxyhydroxide (hereinafter also referred to as "precursor") of manganese, nickel, and optionally Co and M. 1 It can be obtained by co-precipitating a hydroxide of at least one element selected from the group consisting of hydroxyl groups and an alkali metal hydroxide.

[0012] Preferably, the metal portion of the precursor has a composition according to formula 1: (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38, b ranges from zero to 0.05, c is in the range of 0.60 to 0.70, d ranges from zero to 0.05, a+b+c=1).

[0013] Preferably, both b and d are zero.

[0014] In one embodiment of the present invention, the precursor has an average particle size D50 in the range of 2 to 20 μm, preferably 6 to 15 μm. Average particle size D50 in the context of the present invention refers to the average value of the particle size based on volume, which can be determined, for example, by light scattering.

[0015] In one embodiment of the invention, the width of the particle size distribution of the precursor, expressed as [(D90)-(D10) / (D50) diameter], is at least 0.61, for example 0.61-2.

[0016] In one embodiment of the present invention, M 1 contains Mg in the range of 0.1 to 2.5 mol % relative to the total amount of metals in the precursor.

[0017] In one embodiment of the invention, the precursor has 0.01 to 10 mol %, preferably 0.3 to 5 mol %, of anions other than hydroxide or carbonate, such as sulfate, based on the total number of anions.

[0018] In one embodiment of the invention, the precursor comprises manganese, nickel, and optionally cobalt and M 1 It is prepared by combining an aqueous solution of a water-soluble salt of (solution (α)) with an aqueous solution of an alkali metal hydroxide (solution (β)).

[0019] The term water-soluble salts of manganese and nickel, or metals other than nickel and manganese, refers to salts that have a solubility of 25 g / l or more in distilled water at 25°C, the amount of salt being determined excluding water of crystallization and water resulting from aquo complexes. The water-soluble salts of nickel, cobalt and manganese are preferably Ni 2+ and Mn 2+ Examples of water-soluble salts of nickel and manganese include sulfates, nitrates, acetates, and halides, particularly chlorides. Nitrates and sulfates are preferred, and sulfates are more preferred.

[0020] In one embodiment of the present invention, the concentration of solution (α) can be selected within a wide range. Preferably, the total concentration is selected to be in the range of 1 to 1.8 moles of transition metal per kg of solution, more preferably 1.5 to 1.7 moles of transition metal per kg of solution. As used herein, "transition metal salt" refers to nickel and manganese, and, where applicable, cobalt and manganese. 1and may include salts of other metals, such as magnesium or aluminum, or transition metals other than nickel and manganese.

[0021] Another example of a water-soluble salt is alum, KAl(SO4)2.

[0022] Solution (α) may have a pH value in the range of 2 to 5. In embodiments where a higher pH value is desired, ammonia may be added to solution (α). However, it is preferred not to add ammonia.

[0023] The solution (β) is an aqueous solution of an alkali metal hydroxide. Examples of alkali metal hydroxides include lithium hydroxide, potassium hydroxide and a combination of sodium hydroxide and potassium hydroxide are preferred, and sodium hydroxide is even more preferred.

[0024] Solution (β) may contain a certain amount of carbonate, for example, due to aging of the solution or of the respective alkali metal hydroxide.

[0025] The pH value of the solution (β) is preferably 13 or higher, for example 14.5.

[0026] It is preferred that no ammonia be used during the step of combining solutions (α) and (β).

[0027] In one embodiment of the present invention, the pH value at the end of the step of combining solutions (α) and (β) is measured in the mother liquor at 23°C and is in the range of 8 to 12, preferably 10.5 to 12.0, and more preferably 11.0 to 12.0.

[0028] In one embodiment of the present invention, the co-precipitation is carried out at a temperature in the range of 10 to 85°C, preferably in the range of 20 to 60°C.

[0029] In one embodiment of the present invention, the co-precipitation is carried out under an inert gas, for example a noble gas such as argon, or N2.

[0030] In one embodiment of the invention, a slight excess of hydroxide is applied, for example 0.1 to 10 mol %.

[0031] Solutions (α) and (β) are combined to form a slurry. The solid can be separated by solid-liquid separation techniques, such as decantation, filtration, and centrifugation, with filtration being preferred. A precursor is obtained. The precursor is then dried, for example, in air at a temperature in the range of 100-120°C. Preferably, the residual moisture content of the precursor is 1% by weight or less, for example, 0.01-0.5% by weight. In step (b), a lithium source is added to the precursor. To carry out step (b) of the method of the present invention, for example, the precursor may be mixed with at least one lithium compound selected from Li2O, LiOH, Li2O2 and Li2CO3, where water of crystallization is ignored in the context of the present invention. A preferred lithium source is Li2CO3.

[0032] To carry out step (b), the amounts of precursor and lithium source are selected to obtain the stoichiometry of the desired inventive material. Preferably, the precursor and lithium source compound(s) are selected so that the molar ratio of lithium to the sum of all transition metals and any M is in the range of 1.275:1 to 1.42:1, preferably 1.30:1 to 1.38:1, and even more preferably 1.32:1 to 1.36:1.

[0033] Step (b) can be carried out, for example, in a plowshare mixer, a ball mill or a tumble mixer. For laboratory experiments, roller mills, planetary ball mills and mortars with a pestle can also be used.

[0034] To carry out step (c) of the method of the present invention, according to step (c), the obtained mixture is calcined at a temperature in the range of 650 to 1000° C., preferably 875 to 950° C. This temperature refers to the maximum temperature.

[0035] Step (c) of the process of the present invention can be carried out in a furnace such as a rotary tube furnace, a muffle furnace, a pendulum furnace, a roller hearth furnace or a push-through furnace, or a combination of two or more of the above furnaces.

[0036] Step (c) of the method of the present invention can be carried out for a period of 30 minutes to 24 hours, preferably 3 to 12 hours. Step (c) can be carried out at a temperature level or a temperature profile can be carried out.

[0037] According to the present invention, step (c) is carried out in an atmosphere containing 0.05 to 5% by volume of oxygen, preferably 0.1 to 2% by volume of oxygen. Preferably, the remainder of the atmosphere in step (c) is a non-oxidizing gas selected from nitrogen and a noble gas, and combinations thereof. A preferred noble gas is argon. However, the remainder of the atmosphere may contain moisture and / or CO2 generated during the reaction in addition to the non-oxidizing gas selected from nitrogen and a noble gas.

[0038] In one embodiment of the present invention, at least one pre-baking step (c) is carried out between steps (b) and (c). * ) is being carried out. * ) involves heating the mixture obtained in step (b) at a temperature in the range of 300 to 700°C for 2 to 24 hours.

[0039] During the temperature change, a heating rate of 1 K / min to 10 K / min can be obtained, preferably 2 to 5 K / min.

[0040] After step (c), the resulting material is preferably allowed to cool to room temperature.

[0041] By carrying out the method of the present invention, an electrode active material having excellent electrochemical properties can be obtained.

[0042] The method of the present invention may comprise a further step (d) following step (c), wherein said step (d) is selected from a coating step and a wet processing step. A further (optional) step is a sieving step after step (c).

[0043] In one embodiment of the present invention, the method further comprises step (d) following step (c), wherein step (d) is selected from a coating step and a wet treatment step. An example of a coating step is a dry coating step in which a powdered oxide, hydroxide, or oxyhydroxide of a metal, such as aluminum, titanium, or zirconium, is added, followed by a heat treatment similar to step (c). Another example of a coating step is atomic layer deposition, which alternates between exposure to an alkyl compound of the metal and exposure to moisture. Another example of a coating step is combining a solution of a metal compound, such as an alcoholate, with the cathode active material to deposit the metal oxide or hydroxide on the outer surface of the cathode active material.

[0044] An example of a wet treatment is washing the cathode active material with water, followed by drying and, optionally, a heat treatment such as step (c).

[0045] A further aspect of the present invention relates to the particulate material defined at the outset, which is defined below as inventive material or material according to the invention. The inventive material is explained in more detail below.

[0046] The material of the present invention has the composition Li 1+x TM 1-x O2, where x is in the range of 0.1 to 0.2, and TM is represented by the general formula (I): (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38, b is in the range of zero to 0.05, and preferably b is zero; c is in the range of 0.60 to 0.70, d ranges from zero to 0.05, a+b+c=1, M 1 is selected from Al, Ti, Zr, W, Mo, Mg, B and a combination of at least two of the above, with Al being preferred) is a combination of elements by The particulate material has a density of 2.75 to 3.1 g / cm determined at a pressure of 250 MPa. 3 , preferably 2.80 to 3.10 g / cm 3 The compressed density ranges from 1000 to 10 ...

[0047] The materials of the present invention have an average particle size D50 in the range of 2 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.

[0048] In one embodiment of the present invention, the electrode active material of the present invention has a surface area of ​​0.7 to 3.8 mPa, determined according to DIN-ISO 9277:2003-05. 2 / g, with a surface area (BET) ranging from 1.5 to 3.8 m 2 / g is preferred.

[0049] Some metals are ubiquitous, e.g., sodium, calcium, or zinc, and trace amounts thereof are present virtually everywhere, but such trace amounts are not considered within the context of the present invention. Trace amounts in this context mean amounts of 0.05 mole % or less, based on the total metal content TM.

[0050] M 1 may be homogeneously or heterogeneously dispersed in the particles of the material of the present invention. 1 is distributed non-uniformly, even more preferably in a gradient (M 1The concentration is higher in the center of the particle than in the center of the particle.

[0051] In one embodiment of the present invention, the material of the present invention is composed of spherical particles, i.e., particles having a spherical shape, including not only particles that are precisely spherical, but also particles in which the difference between the maximum and minimum diameters of at least 90% (number average) of a representative sample is 10% or less.

[0052] In one embodiment of the present invention, the material of the present invention is composed of secondary particles that are agglomerates of primary particles. Preferably, the material of the present invention is composed of spherical secondary particles that are agglomerates of primary particles. Even more preferably, the material of the present invention is composed of spherical secondary particles that are agglomerates of platelet-shaped primary particles.

[0053] In one embodiment of the present invention, the primary particles of the material of the present invention have an average diameter in the range of 1 to 2000 nm, preferably 10 to 1000 nm, particularly preferably 50 to 500 nm. The average primary particle size can be determined, for example, by SEM or TEM. SEM is an abbreviation for scanning electron microscope, and TEM is an abbreviation for transmission electron microscope.

[0054] In one embodiment of the present invention, the volumetric energy density (VED) is in the range of 2,750 to 3,100 W·h / l. VED is defined as follows: VED = 1st cycle discharge capacity × average voltage × packed density.

[0055] In one embodiment of the invention, the material of the invention has a unimodal particle size distribution. In an alternative embodiment, the material of the invention has a bimodal particle size distribution, for example with a maximum in the range of 3-6 μm and another maximum in the range of 9-12 μm.

[0056] In one embodiment of the present invention, the compressed density of the material of the present invention is between 2.75 and 3.1 g / cm, determined at a pressure of 250 MPa. 3 The range is 2.85 to 3.10 g / cm 3 is preferred.

[0057] In one embodiment of the invention, the material of the invention has a viscosity of 1.20 to 1.80 g / cm, as determined after 2000 taps with a graduated cylinder. 3 The tap density ranges from 0.1 to 1.0.

[0058] The materials of the present invention are particularly well suited as cathode active materials because they exhibit both high energy density and high energy density retention.

[0059] A further aspect of the present invention is an electrode comprising at least one cathode active material of the present invention. These are particularly useful in lithium-ion batteries. Lithium-ion batteries comprising at least one electrode according to the present invention exhibit very good discharge and cycling behavior, and they also exhibit good safety behavior.

[0060] In one embodiment of the present invention, the cathode of the present invention comprises: (A) at least one material of the present invention as described above; (B) carbon in a conductive state, and (C) binder, (D) Current collector Contains:

[0061] In a preferred embodiment of the present invention, the cathode of the present invention comprises, based on the sum of (A), (B), and (C): (A) 80 to 99% by mass of the material of the present invention; (B) 0.5 to 19.5 mass% carbon; (C) 0.5 to 9.5 mass% of a binder material Contains:

[0062] The cathode according to the present invention contains a conductively modified carbon, also referred to simply as carbon (B). Carbon (B) can be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite. Carbon (B) can be added directly during the preparation of the electrode material according to the present invention.

[0063] The electrodes according to the present invention may contain further components, such as a current collector (D), for example (but not limited to) aluminum foil. They may further contain a binder material (C), also referred to as binder (C) hereinafter. The current collector (D) will not be further described here.

[0064] Suitable binders (C) 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] Another preferred binder (C) is polybutadiene.

[0070] Other suitable binders (C) are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

[0071] In one embodiment of the present invention, the binder (C) 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:

[0072] The binder (C) may be a crosslinked or non-crosslinked (co)polymer.

[0073] In a particularly preferred embodiment of the present invention, the binder (C) 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.

[0074] Suitable binders (C) are especially polyvinyl alcohol and halogenated (co)polymers such as polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvinyl fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.

[0075] The electrode of the present invention may contain 0.5 to 9.5 mass % of binder(s) (C) based on the total of component (A), carbon (B) and binder (C).

[0076] A further aspect of the present invention is (A) at least one cathode comprising the material of the present invention (A), carbon (B) and a binder (C); (B) at least one anode, and (C) at least one electrolyte It is a battery containing

[0077] The embodiment of the cathode (1) has already been described in detail above.

[0078] The anode (2) may contain at least one anode active material, such as carbon (graphite), TiO2, lithium titanium oxide, silicon, or tin. The anode (2) may further contain a current collector, such as a metal foil, such as copper foil.

[0079] The electrolyte (3) may include at least one non-aqueous solvent, at least one electrolyte salt, and optionally an additive.

[0080] The non-aqueous solvent for the electrolyte (3) can 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.

[0081] 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.

[0082] The molecular weight M of suitable polyalkylene glycols, especially suitable polyethylene glycols, W may be at least 400 g / mol.

[0083] 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.

[0084] 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.

[0085] Examples of suitable cyclic ethers are tetrahydrofuran and 1,4-dioxane.

[0086] Examples of suitable acyclic acetals are, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane and 1,1-diethoxyethane.

[0087] An example of a suitable cyclic acetal is 1,3-dioxane, and especially 1,3-dioxolane.

[0088] Examples of suitable acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.

[0089] Examples of suitable cyclic organic carbonates are compounds of the general formulae (II) and (III) [ka] (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).

[0090] 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.

[0091] Another preferred cyclic organic carbonate is vinylene carbonate of formula (IV).

[0092] [ka]

[0093] 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.

[0094] The electrolyte (3) 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).

[0095] Preferred electrolyte salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred.

[0096] In a preferred embodiment of the present invention, the electrolyte (3) contains at least one flame retardant. Useful flame retardants may be selected from trialkyl phosphates (wherein the alkyls are different or the same), triaryl phosphates, alkyl dialkyl phosphonates, and halogenated trialkyl phosphates. Preferred are tri-C1-C4-alkyl phosphates (wherein the C1-C4-alkyls are different or the same), tribenzyl phosphate, triphenyl phosphate, C1-C4-alkyl di-C1-C4-alkyl phosphonates, and fluorinated tri-C1-C4-alkyl phosphates.

[0097] In a preferred embodiment, the electrolyte (3) comprises at least one flame retardant selected from trimethyl phosphate, CH3-P(O)(OCH3)2, triphenyl phosphate, and tris-(2,2,2-trifluoroethyl)-phosphate.

[0098] The electrolyte (3) may contain 1 to 10 mass % of a flame retardant based on the total mass of the electrolyte.

[0099] In an embodiment of the present invention, the battery according to the present invention includes one or more separators (4) by which the electrodes are mechanically separated. Preferred separators (4) are polymer films, particularly porous polymer films, that are unreactive with metallic lithium. Particularly preferred materials for separators (4) are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0100] The separator (4) made of polyolefin, particularly polyethylene or polypropylene, can have a porosity in the range of 35 to 50%. The preferred pore size is, for example, in the range of 30 to 500 nm.

[0101] In another embodiment of the present invention, the separator (4) 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.

[0102] The battery according to the invention further comprises a housing which may have any shape, for example a cube or a cylindrical disk. In one variant, a metal foil configured as a pouch is used as the housing.

[0103] The battery according to the invention exhibits very good discharge and cycling behavior, especially with regard to capacity loss, especially at high temperatures (above 45° C., for example up to 60° C.).

[0104] 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.

[0105] 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.

[0106] The present invention is further illustrated by examples. [Example]

[0107] General Notes: Unless otherwise stated, percentages are by weight.

[0108] ICP: Inductively Coupled Plasma Comparative examples of step (c) utilized cylinders with appropriate mixtures of O2 and argon (where applicable) under 100% O2 and 21% O2.

[0109] In the present example of step (c), appropriate volumes of mixtures of 21% O in argon and pure argon under 1% O and 0.1% O were used by simultaneously flowing them from a premix cylinder at flow rates controlled to achieve the desired oxygen partial pressure.

[0110] PVdF: Polyvinylidene fluoride The specific surface area (BET) was determined according to DIN-ISO 9277:2003-05.

[0111] I. Preparation of Precursor TM-OH.1, Step (a.1) A stirred tank reactor was filled with deionized water and heated to 45° C. The pH value was then adjusted to 11.3 by adding aqueous sodium hydroxide solution.

[0112] The coprecipitation reaction was initiated by simultaneously feeding aqueous transition metal sulfate solutions and aqueous sodium hydroxide solutions at a flow rate ratio of 1.9, with a total flow rate of 12 hours for an average residence time. The transition metal solution contained Ni and Mn in a 1:2 molar ratio and a total transition metal concentration of 1.65 mol / kg. The aqueous sodium hydroxide solution was a 50% by weight sodium hydroxide solution. The pH value was maintained at 11.3 by separately feeding aqueous sodium hydroxide. Starting from the start of all feeds, the mother liquor was continuously removed. After 29 hours, all feed flows were stopped. The resulting suspension was filtered, washed with distilled water, dried in air at 120°C, and sieved to obtain the mixed transition metal (TM) oxyhydroxide precursor. The precursor TM-OH.1 with an average particle size (D50) of 6 μm was obtained.

[0113] II. Addition of Lithium Source, Step (b) Step (b.1): The precursor TM-OH.1 was mixed with Li2CO3 in a mass ratio of 0.5542 g Li2CO3:1 g TM-OH.1, such that the Li:TM ratio was 1.14:0.86. This mixture was milled in a planetary ball mill at 120 rpm for 30 minutes. A powdery mixture was obtained.

[0114] III. Heat Treatment III.1 Synthesis of the cathode active material CAM.1 of the present invention, step (c.1) Heat treatment, step (c.1): The heat treatment of the mixture obtained in step (b.1) was performed in a tubular furnace according to the following temperature profile: the temperature was increased to 900°C at 1.5°C / min, held at 900°C for 5 hours, and then naturally cooled. During step (c.1), the oxygen content of the mixed gas was continuously monitored with an oxygen sensor and maintained at the desired level. The oxygen content of the atmosphere in step (c.1) was 0.1% by volume. CAM.1 of the present invention was obtained.

[0115] III.2 Synthesis of Cathode Active Material CAM.2 of the Invention, Step (c.2) Step (c.1) was repeated, but the oxygen content of the atmosphere in step (c.1) was 1.0% by volume. CAM.2 of the invention was obtained.

[0116] III.3 Synthesis of Comparative Cathode Active Material C-CAM.3, Step c-(c.3) Step (c.1) was repeated, but the oxygen content of the atmosphere in steps c-(c.3) was 21.0% by volume. Comparative material C-CAM.3 was obtained.

[0117] III.4 Synthesis of Comparative Cathode Active Material C-CAM.4, Steps c-(c.4) Step (c.1) was repeated, but the oxygen content of the atmosphere in steps c-(c.4) was 100% by volume. Comparative material C-CAM.4 was obtained.

[0118] IV. Electrode Test IV.1 Fabrication of the electrode of the present invention by sheet coating For each electrode sheet, the inventive or comparative cathode active material, PVdF, and carbon black were mixed in NMP at a mass ratio of 80:10:10 to obtain a slurry with a ratio of 2.9 mL:1 g of NMP to cathode active material. The resulting slurry was centrifugally mixed for 10 minutes and then immediately coated onto carbon-coated aluminum foil using a doctor blade set at a gap of 100 microns. The electrode sheet was dried at 65°C for 4 hours, then transferred to a vacuum oven set at 60°C for 12 hours, and then transferred to an argon-filled glove box.

[0119] IV.2 Cell Assembly For each cell, a disk approximately 1 cm in diameter was punched and collected to determine the active material gain for that particular cell. Electrochemical testing was performed on a coin-shaped half-cell consisting of the collected cathode disk, Celgard separator (PP-PE-PP trilayer), and lithium foil anode, all soaked in 1 M LiPF in a 1:1 volume ratio of ethylene carbonate:diethyl carbonate. Freshly assembled cells were allowed to rest for a minimum of 3 hours before electrochemical testing. The results are summarized in Table 1.

[0120] Rates were calculated based on 1 C = 250 mA / g. The capacities presented were the discharge capacities of cells charged from 2 V to 4.7 V at 0.5 C, held at 4.7 V until a current of 0.02 C was reached, and then discharged to 2 V at the given rate.

[0121] [Table 1]

[0122] All capacities are expressed in mA·h / g. nd:Undecided, The compressed densities of CAM.1 and CAM.2 were within the claimed range.

Claims

1. Formula Li １＋ｘ TM １－ｘ O ２ wherein x is in the range of 0.1 to 0.2, and TM is a compound of general formula (I): (Ni a Co b Mr c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38; b ranges from zero to 0.05; c is in the range of 0.60 to 0.70; d ranges from zero to 0.05; M １ is selected from Al, Ti, Zr, W, Mo, Nb, Ta, Mg, and a combination of at least two of the above; a + b + c = 1) It is a combination of elements by The method comprises the following steps: (a) manganese, nickel, and optionally Co and M １ providing a particulate hydroxide, oxide or oxyhydroxide with at least one of (b) adding a lithium source; (c) firing the mixture resulting from step (b) at a maximum temperature in the range of 650 to 1000°C in an atmosphere containing 0.05 to 5% by volume of oxygen; A method comprising:

2. 10. The method of claim 1, wherein step (c) is carried out under a forced flow of gas.

3. 3. The method of claim 1 or 2, wherein step (c) is carried out in a roller hearth kiln, a pusher kiln, or a rotary hearth kiln.

4. 4. The method according to claim 1, wherein step (c) is carried out in an atmosphere containing 0.1 to 2% by volume of oxygen.

5. 5. The method of claim 1, wherein the remainder of the atmosphere in step (c) is a non-oxidizing gas selected from nitrogen and a noble gas.

6. The lithium source is lithium hydroxide, lithium carbonate, lithium oxide, and Li ２ O ２ The method according to any one of claims 1 to 5, wherein the compound is selected from the group consisting of:

7. 7. The method according to any one of claims 1 to 6, wherein the method comprises a further step (d) following step (c), said step (d) being selected from a coating step and a wet processing step.

8. Composition Li １＋ｘ TM １－ｘ O ２ wherein x is in the range of 0.1 to 0.2, and TM is a particulate material of general formula (I): (Ni a Co b Mr c ) 1-d M 1 d (I) (wherein a is in the range of 0.30 to 0.38; b ranges from zero to 0.05; c is in the range of 0.60 to 0.70; d ranges from zero to 0.05; M １ is selected from Al, Ti, Zr, W, Mo, Mg, Nb, Ta, and a combination of at least two of the above; a + b + c = 1) It is a combination of elements by The particulate material has an average particle size D50 in the range of 2 to 20 μm, and a specific surface area (BET) in the range of 0.7 to 3.8 m ２ / g, and The particulate material has a compressed density in the range of 2.75 to 3.1 g / cm 3 .

9. M １ 9. The particulate material of claim 8, wherein is Al and b is zero.

10. Specific surface area is 1.5 to 3.8 m ２ 10. The particulate material according to claim 8 or 9, wherein the molecular weight is in the range of / g.

11. (A) at least one cathode active material according to any one of claims 8 to 10; (B) carbon in a conductive state; (C) at least one binder a cathode.

12. An electrochemical cell comprising the cathode of claim 11.

Images