EP4367726A1 - Process for making a coated cathode active material, and coated cathode active material - Google Patents

Process for making a coated cathode active material, and coated cathode active material

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Publication number
EP4367726A1
EP4367726A1 EP22733935.5A EP22733935A EP4367726A1 EP 4367726 A1 EP4367726 A1 EP 4367726A1 EP 22733935 A EP22733935 A EP 22733935A EP 4367726 A1 EP4367726 A1 EP 4367726A1
Authority
EP
European Patent Office
Prior art keywords
range
active material
zero
electrode active
metals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP22733935.5A
Other languages
German (de)
French (fr)
Inventor
Xiaohan WU
Heino Sommer
Ben Breitung
Simon SCHWEIDLER
Miriam BOTROS
Torsten Brezesinski
Horst Hahn
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Karlsruher Institut fuer Technologie KIT
Original Assignee
BASF SE
Karlsruher Institut fuer Technologie KIT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF SE, Karlsruher Institut fuer Technologie KIT filed Critical BASF SE
Publication of EP4367726A1 publication Critical patent/EP4367726A1/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/30—Batteries in portable systems, e.g. mobile phone, laptop
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention is directed towards a process for making a coated electrode active mate rial wherein said process comprises the following steps:
  • step (c) removing the solvent from step (b), thereby obtaining a solid residue
  • step (d) exposing the solid residue from step (c) to 3 to 10 pulses of electromagnetic radiation with a wavelength in the range of from 200 to 1400 nm, wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds,
  • the present invention is directed towards Ni-rich electrode active materials.
  • Lithium ion secondary batteries are modern devices for storing energy. Many application fields have been and are contemplated, from small devices such as mobile phones and laptop com puters through car batteries and other batteries for e-mobility. Various components of the batter ies have a decisive role with respect to the performance of the battery such as the electrolyte, the electrode materials, and the separator. Particular attention has been paid to the cathode materials. Several materials have been suggested, such as lithium iron phosphates, lithium co balt oxides, and lithium nickel cobalt manganese oxides. Although extensive research has been performed the solutions found so far still leave room for improvement.
  • Ni-rich electrode active materials for example electrode active materials that contain 75 mole-% or more of Ni, referring to the total TM content.
  • inventive process comprises at least three steps, step (a), step (b) and step (c). Said steps are described in more detail below.
  • Step (a) includes providing an electrode active material according to general formula Lii +x TMi- x C>2, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, preferably Ni and a combination of Co and Mn or Ni and a combination of Co and Al, and, optionally, at least one metal selected from Mg, Ti and Zr, and x is in the range of from zero to 0.2, preferably 0.01 to 0.05.
  • at least 60 mol-% of TM is nickel.
  • the particulate material has an average particle di ameter (D50) in the range of from 3 to 20 pm, preferably from 5 to 16 pm.
  • the average particle diameter can be determined, e. g., by light scattering or LASER diffraction.
  • the particles are usually composed of agglomerates from primary particles, and the above particle diameter re fers to the secondary particle diameter.
  • the particulate material has a specific surface, hereinafter also “BET surface” in the range of from 0.1 to 1 .5 m 2 /g.
  • BET surface may be determined by nitrogen adsorption after outgassing of the sample at 200 °C for 30 minutes or more and beyond this accordance with DIN ISO 9277:2010.
  • TM corresponds to general formula (I a)
  • M is at least one of Al, Mg, Ti, and Zr, preferably at least one of Al, Ti, and Zr.
  • M is Al
  • d is in the range of from 0.01 to 0.05.
  • variable TM corresponds to general formu la (I b)
  • variable x for Lii +x TMi- x 0 2 and TM corresponding to formula (I b) is preferably in the range of from 0.05 to 0.2, more preferably from 0.1 to 0.15.
  • TM is selected from Nio .6 Coo .2 Mn 0.2 , Nio . Coo .2 Mno .i , Nio.eCoo.iMno.i, Ni0.83Co0.12Mn0.05, Ni0.89Co0.055AI0.055, Ni0.91Co0.045AI0.045 and Ni0.85Co0.1Mn0.05 ⁇
  • the electrode active material provided in step (a) is usually free from conductive carbon, that means that the conductive carbon content of starting material is less than 1% by weight, refer preferably 0.001 to 1 .0 % by weight and even more below detec tion level.
  • traces of ubiquitous met als such as sodium, calcium, iron or zinc, as impurities will not be taken into account in the de scription of the present invention. Traces in this context will mean amounts of 0.02 mol-% or less, referring to the total metal content of the starting material. Traces of sulfate are neglected as well.
  • the electrode active material provided in step (a) may have has a moisture content in the range of from 5 to 1 ,500 ppm, preferably 10 to 1 ,200 ppm, ppm being parts per million (weight).
  • step (b) said electrode active material is contacted with a solution of salts of M 2 wherein M 2 is a combination of metals that includes Co, Cu, Ni, Zn and Mg in one or more sub-steps, prefera bly in one step.
  • Said solution may be a solution in an alcohol such as methanol or ethanol. In other embodiments, said solution is an aqueous solution.
  • Said contacting is preferably a slurry ing.
  • salts of M 2 are selected from salts that have a minimum solubility of 25 g/l in the respective solvent - alcohol or water - at ambient temperature, preferably a minimum solubility of 50 g/l.
  • M 2 additionally includes at least one of lithium and Fe and V.
  • sulfates and halides such as chlorides and bromides, furthermore nitrates and acetates. Sulfates may lead to non-volatile residues, and halides such as chlorides are unde sired in various types of electrochemical cells.
  • nitrates and acetates are preferred, nitrates being more preferred.
  • molar ratio of metals other than Li if appli cable, in M 2 is in each case the same or deviates by at most 10 mol-%, preferably by at most 5 mol-%.
  • the total molar ratio of M 2 to TM is in the range of from 0.1 to 5%, preferably 1 to 5%.
  • the molar ratio of lithium to the molar ratio of all the metals other than Li in M 2 is in the range of from 1 :2 to 1 :3.
  • the concentration of M 2 in the solution of salts is in the range of from 0.5 to 1 mol/l, preferably 0.6 to 1 mol/l.
  • the volume ratio of the solution of salts of M 2 to electrode active material provided in step (a) is in the range of from 3:1 to 1 :3.
  • Step (b) is performed at a temperature in the range of from 5°C to 85°C, preferably 15 to 40 °C.
  • the duration of step (b) is in the range of from 10 minutes to 5 hours, preferably from 30 to 90 minutes.
  • step (b) is supported by mixing operation, for ex ample stirring. On laboratory scale, mixing with a magnetic stirrer is feasible.
  • Step (b) may be performed at any pressure but ambient pressure is preferred.
  • Step (b) may be performed in one step or in two or more sub-steps, one single step being pre ferred.
  • Sub-steps may include a subsequent addition of single components of M 2 .
  • Step (c) includes removal of the solvent, especially water, as well as removal of volatile by-products such as nitric acid or acetic acid, if applicable, prefer ably by evaporation.
  • the conditions under which such solvent is evaporated depends on its vol atility.
  • the temperature may be in the range of from 50 to 150 °C, and the pressure may be in the range of from 1 mbar to 1 bar (abs).
  • step (d) A solid residue is obtained that is subsequently subjected to step (d).
  • step (d) the residue obtained from step (c) is exposed to electromagnetic radiation with a wavelength in the range of from 200 to 1400 nm.
  • step (d) is performed at a temperature in the range of from 5°C to 85°C, preferably 15 to 40 °C. It is observed that during step (d) the residue heats up, for example to 200°C or even more.
  • the duration of step (b) is in the range of from 10 minutes to 5 hours, preferably from 30 to 90 minutes.
  • step (d) is supported by mixing operation, for ex ample stirring. On laboratory scale, mixing with a magnetic stirrer is feasible.
  • step (d) is performed in the form of exposing the residue from step (c) to 3 to 10 pulses of electromagnetic radiation with a wavelength from 200 to 1400 nm in the form of several pulses wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds.
  • a pulse has a duration in the range of from 1 ms to 2 sec onds, preferably 10 ms to 50 ms, and the number of pulses is in the range of from 3 to 10, pref erably 4 to 7.
  • the distance of the residue from step (c) to the source of radiation is preferably in the range of from 5 to 15 mm.
  • the various pulses are about identical in duration.
  • step (e) of the inventive process the material so obtained is heat-treated in an oxygen- containing atmosphere at a temperature in the range of from 300 to 750 °C for 10 minutes to 4 hours.
  • Step (e) may be carried out in any type of oven, for example a roller hearth kiln, a pusher kiln, a rotary kiln, a pendulum kiln, or - for lab scale trials - in a muffle oven.
  • oven for example a roller hearth kiln, a pusher kiln, a rotary kiln, a pendulum kiln, or - for lab scale trials - in a muffle oven.
  • the temperature of the thermal treatment according to step (e) may be in the range of from 300 to 750 °C, preferably 350 to 650 °C. Said temperature refers to the maximum temperature of step (e).
  • the temperature is ramped up before reaching the desired temperature of from 300 to 750 °C.
  • the material resulting from step (d) is heated to a temperature to 75 to 90 °C and then held constant for a time of 10 min to 0.5 hours, and then it is raised to 300 to 750 °C.
  • the heating rate in step (e) is in the range of from 0.1 to 10 °C/min.
  • step (e) is performed in a roller hearth kiln, a push er kiln or a rotary kiln or a combination of at least two of the foregoing.
  • Rotary kilns have the advantage of a very good homogenization of the material made therein.
  • different reaction conditions with respect to different steps may be set quite easily.
  • box-type and tubular furnaces and split tube furnaces are feasible as well.
  • step (e) is performed in an oxygen-containing at mosphere, for example in a nitrogen-air mixture, in a rare gas-oxygen mixture, in air, in oxygen or in oxygen-enriched air or in pure oxygen.
  • the atmosphere in step (e) is selected from air, oxygen and oxygen-enriched air.
  • Oxygen-enriched air may be, for ex ample, a 50:50 by volume mix of air and oxygen.
  • Other options are 1 :2 by volume mixtures of air and oxygen, 1 :3 by volume mixtures of air and oxygen, 2:1 by volume mixtures of air and oxygen, and 3:1 by volume mixtures of air and oxygen. Pure oxygen is even more preferred.
  • step (e) has a duration in the range of from 10 minutes to 4 hours. Preferred are 60 minutes to 3 hours. The cooling time is neglected in this context.
  • coated electrode active materials are obtained with excel lent electrochemical properties.
  • a high entropy oxide of M 2 is formed that is enriched at the surface of the primary particles of the compound of general formula Lii +x TMi- x 02.
  • a further aspect of the present invention is related to particulate materials, hereinafter also re ferred to as inventive cathode active materials or inventive particulate materials or inventive coated particulate materials.
  • Inventive particulate cathode active materials comprise a core material according to general formula Lii +xi TMi- xi 0 2 wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, optionally, at least one metal selected from Al, Mg, Ti and Zr, and x1 is in the range of from -0.02 to 0.2, wherein the outer surface of the core material contains an oxide compound of M 2 wherein M 2 contains Co, Cu, Ni, Zn and Mg. Said outer surface may hereinafter also be referred to as coating.
  • variable x1 may be somewhat smaller than x because of Li removal in the course of the M2 treatment process.
  • Inventive coated particulate materials in the context with the present invention refer to at least 80% of the particles of a batch of particulate material being coated, and to at least 75% of the surface of each particle being coated, for example 75 to 99.99 % and preferably 80 to 90%.
  • the thickness of such coating may be very low, for example 0.1 to 5 nm. In other embodiments, the thickness may be in the range of from 6 to 15 nm. In further embodiments, the thickness of such coating is in the range of from 16 to 50 nm.
  • the inventive coated particulate material has an average particle diameter (D50) in the range of from 3 to 20 pm, preferably from 5 to 16 pm.
  • the average particle diameter can be determined, e. g., by light scattering or LASER diffraction.
  • the particles are usually composed of agglomerates from primary particles, and the above par ticle diameter refers to the secondary particle diameter.
  • the inventive coated particulate material has a specific surface, hereinafter also “BET surface” in the range of from 0.1 to 1 .5 m 2 /g.
  • the BET surface may be determined by nitrogen adsorption after outgassing of the sample at 200 °C for 30 minutes or more and beyond this accordance with DIN ISO 9277:2010.
  • said coating comprises a compound selected from an oxide of M 2 and a sub-stoichiometrically lithiated oxide of M 2 .
  • the molar ratio of metals other than Li, if applicable, in M 2 is in each case the same or deviates by at most 10 mol-%, preferably by at most 5%.
  • TM is a combination of metals according to general formula (I a)
  • variable TM corresponds to general formu la (I b)
  • Inventive cathode active materials may be obtained by the inventive process. Without wishing to be bound by any theory, it is assumed that a high entropy oxide of M 2 is formed that is enriched at the surface of the primary particles of the compound of general formula Lii +x TMi- x 02.
  • Inventive cathode active materials display excellent properties especially with respect to cycling stability and low capacity fade.
  • a further aspect of the present invention refers to electrodes comprising at least one electrode active material according to the present invention. They are particularly useful for lithium ion batteries. Lithium ion batteries comprising at least one electrode according to the present inven tion exhibit a good discharge behavior. Electrodes comprising at least one electrode active ma- terial according to the present invention are hereinafter also referred to as inventive cathodes or cathodes according to the present invention.
  • inventive cathodes contain
  • binder material also referred to as binders or binders (C)
  • binders also referred to as binders or binders (C)
  • inventive cathodes contain
  • (C) 1 to 15 % by weight of binder material, percentages referring to the sum of (A), (B) and (C).
  • Cathodes according to the present invention can comprise further components. They can com prise a current collector, such as, but not limited to, an aluminum foil. They can further comprise conductive carbon and a binder.
  • Cathodes according to the present invention contain carbon in electrically conductive modifica tion, in brief also referred to as carbon (B).
  • Carbon (B) can be selected from soot, active carbon, carbon nanotubes, graphene, and graphite, and from combinations of at least two of the forego ing.
  • 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, catalytic or free-radical (co)polymerization, especially from polyethylene, polyacrylo nitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth)acrylonitrile and 1 ,3-butadiene.
  • Polypropylene is also suita ble.
  • Polyisoprene and polyacrylates are additionally suitable. Particular preference is given to polyacrylonitrile.
  • polyacrylonitrile is understood to mean not only polyacry lonitrile homopolymers but also copolymers of acrylonitrile with 1 ,3-butadiene or styrene. Pref erence is given to polyacrylonitrile homopolymers.
  • polyethylene is not only understood to mean homopoly ethylene, but also copolymers of ethylene which comprise at least 50 mol-% of copolymerized ethylene and up to 50 mol-% of at least one further comonomer, for example a-olefins such as propylene, butylene (1 -butene), 1 -hexene, 1 -octene, 1 -decene, 1 -dodecene, 1 -pentene, and also isobutene, vinylaromatics, for example styrene, and also (meth)acrylic acid, vinyl acetate, vinyl propionate, CrCio-alkyl esters of (meth)acrylic acid, especially methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-
  • polypropylene is not only understood to mean homopol ypropylene, but also copolymers of propylene which comprise at least 50 mol-% of copolymer ized propylene and up to 50 mol-% of at least one further comonomer, for example ethylene and a-olefins such as butylene, 1 -hexene, 1 -octene, 1 -decene, 1 -dodecene and 1 -pentene.
  • Pol ypropylene is preferably isotactic or essentially isotactic polypropylene.
  • polystyrene is not only understood to mean homopoly mers of styrene, but also copolymers with acrylonitrile, 1 ,3-butadiene, (meth)acrylic acid, Ci- Cio-alkyl esters of (meth)acrylic acid, divinylbenzene, especially 1 ,3-divinylbenzene, 1 ,2- diphenylethylene and a-methylstyrene.
  • Another preferred binder (C) is polybutadiene.
  • Suitable binders (C) are selected from polyethylene oxide (PEO), cellulose, carbox- ymethylcellulose, polyimides and polyvinyl alcohol.
  • binder (C) is selected from those (co)polymers which have an average molecular weight M w in the range from 50,000 to 1 ,000,000 g/mol, pref erably to 500,000 g/mol.
  • Binder (C) may be selected from cross-linked or non-cross-linked (co)polymers.
  • binder (C) is selected from hal- ogenated (co)polymers, especially from fluorinated (co)polymers.
  • Halogenated or fluorinated (co)polymers are understood to mean those (co)polymers which comprise at least one (co)polymerized (co)monomer which has at least one halogen atom or at least one fluorine at om per molecule, more preferably at least two halogen atoms or at least two fluorine atoms per molecule.
  • Examples are polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, pol- yvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymers, perfluoroalkyl vinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-chlorotrifluoroethylene copolymers and ethylene-chlorofluoroethylene copol ymers.
  • PVdF pol- yvinylidene fluoride
  • PVdF-HFP vinylidene fluoride-hexafluoropropylene copolymers
  • PVdF-HFP vinylidene fluoride-tetrafluor
  • Suitable binders (C) are especially polyvinyl alcohol and halogenated (co)polymers, for example polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvi nyl fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.
  • inventive cathodes may comprise 1 to 15% by weight of binder(s), referring to electrode active material. In other embodiments, inventive cathodes may comprise 0.1 up to less than 1% by weight of binder(s).
  • a further aspect of the present invention is a battery, containing at least one cathode comprising inventive electrode active material, carbon, and binder, at least one anode, and at least one electrolyte.
  • Said anode may contain at least one anode active material, such as carbon (graphite), T1O2, lithium titanium oxide, silicon or tin.
  • Said anode may additionally contain a current collector, for example a metal foil such as a copper foil.
  • Said electrolyte may comprise at least one non -aqueous solvent, at least one electrolyte salt and, optionally, additives.
  • Non-aqueous solvents for electrolytes can be liquid or solid at room temperature and is prefera bly selected from among polymers, cyclic or acyclic ethers, cyclic and acyclic acetals and cyclic or acyclic organic carbonates.
  • suitable polymers are, in particular, polyalkylene glycols, preferably poly-Ci-C 4 - alkylene glycols and in particular polyethylene glycols.
  • Polyethylene glycols can here comprise up to 20 mol-% of one or more Ci-C4-alkylene glycols.
  • Polyalkylene glycols are preferably poly alkylene glycols having two methyl or ethyl end caps.
  • the molecular weight M w of suitable polyalkylene glycols and in particular suitable polyethylene glycols can be at least 400 g/mol.
  • the molecular weight M w of suitable polyalkylene glycols and in particular suitable polyethylene glycols can be up to 5 000 000 g/mol, preferably up to 2 000 000 g/mol.
  • Suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether,
  • Suitable cyclic ethers are tetrahydrofuran and 1 ,4-dioxane.
  • Suitable acyclic acetals are, for example, dimethoxymethane, diethoxymethane,
  • Suitable cyclic acetals are 1 ,3-dioxane and in particular 1 ,3-dioxolane.
  • Suitable acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.
  • Suitable cyclic organic carbonates are compounds according to the general formu lae (II) and (III) where R 1 , R 2 and R 3 can be identical or different and are selected from among hydrogen and Ci-C4-alkyl, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert- butyl, with R 2 and R 3 preferably not both being tert-butyl.
  • R 1 is methyl and R 2 and R 3 are each hydrogen, or R 1 , R 2 and R 3 are each hydrogen.
  • R 1 is fluorine and R 2 and R 3 are each hy drogen.
  • Another preferred cyclic organic carbonate is vinylene carbonate, formula (IV).
  • the solvent or solvents is/are preferably used in the water-free state, i.e. with a water content in the range from 1 ppm to 0.1% by weight, which can be determined, for example, by Karl-Fischer titration.
  • Electrolyte further comprises at least one electrolyte salt.
  • Suitable electrolyte salts are, in partic ular, lithium salts.
  • Preferred electrolyte salts are selected from among LiC(CF 3 S0 2 ) 3 , LiN(CF 3 S0 2 ) 2 , LiPF 6 , LiBF 4 , UCI0 4 , with particular preference being given to LiPF 6 and LiN(CF 3 S0 2 ) 2 .
  • batteries according to the invention comprise one or more separators by means of which the electrodes are mechanically separated.
  • Suitable separators are polymer films, in particular porous polymer films, which are unreactive toward metallic lithium.
  • Particularly suitable materials for separators are polyolefins, in particular film forming porous polyethylene and film-forming porous polypropylene.
  • Separators composed of polyolefin, in particular polyethylene or polypropylene, can have a po rosity in the range from 35 to 45%. Suitable pore diameters are, for example, in the range from 30 to 500 nm.
  • separators can be selected from among PET nonwovens filled with inorganic particles.
  • Such separators can have porosities in the range from 40 to 55%. Suitable pore diameters are, for example, in the range from 80 to 750 nm.
  • Batteries according to the invention further comprise a housing which can have any shape, for example cuboidal or the shape of a cylindrical disk or a cylindrical can. In one variant, a metal foil configured as a pouch is used as housing.
  • Batteries according to the invention display a good discharge behavior, for example at low tem peratures (zero °C or below, for example down to -10 °C or even less), a very good discharge and cycling behavior.
  • Batteries according to the invention can comprise two or more electrochemical cells that com bined with one another, for example can be connected in series or connected in parallel. Con nection in series is preferred.
  • at least one of the electrochemical cells contains at least one cathode according to the invention.
  • the majority of the electrochemical cells contains a cathode according to the present invention.
  • all the electrochemical cells contain cathodes according to the present invention.
  • the present invention further provides for the use of batteries according to the invention in ap pliances, in particular in mobile appliances.
  • mobile appliances are vehicles, for example automobiles, bicycles, aircrafts or water vehicles such as boats or ships.
  • Other exam ples of mobile appliances are those which move manually, for example computers, especially laptops, telephones or electric hand tools, for example in the building sector, especially drills, battery-powered screwdrivers or battery-powered staplers.
  • D50 Average particle diameters (D50) were determined by dynamic light scattering (“DLS”). Per centages are % by weight unless specifically noted otherwise.
  • LiOH-hbO was purchased from Rockwood Lithium.
  • base electrode active materials were manufactured in a box furnace, type: VMK-80-S, Linn High Term.
  • Methanol and toluene were pre-dried according to standard laboratory methods.
  • the precipitation reaction was performed at 55°C under a nitrogen atmosphere using a continu ous stirred tank reactor with a volume of 2.3 I.
  • the continuous stirred tank reactor was charged with 1 .5 I of the above aqueous solution of (NH ) 2 SC>4.
  • the pH value of the solution was adjusted to 11 .5 using a 25% by weight aqueous solution of sodium hydroxide.
  • An aqueous metal solution containing N1SO4, C0SO4 and MnS0 4 (molar ratio 85:10:5, total metal concentra tion: 1 .65 mol/kg), aqueous sodium hydroxide (25wt% NaOH) and aqueous ammonia solution (25wt% ammonia) were simultaneously introduced into the vessel.
  • the molar ratio between ammonia and metal was adjusted to 0.265.
  • the sum of volume flows was set to adjust the mean residence time to 5 hours.
  • the flow rate of the NaOH was adjusted by a pH regulation circuit to keep the pH value in the vessel at a constant value of 11 .58.
  • the apparatus was oper ated continuously keeping the liquid level in the vessel constant.
  • a mixed hydroxide of Ni, Co and Mn was collected via free overflow from the vessel.
  • the resulting product slurry contained about 120g/l mixed hydroxide of Ni, Co and Mn with an average particle size (D50) of 10.5 pm, P-CAM.1.
  • a 5-ml-glass vial was charged with 48 ml of an ethanolic solution containing 13.26 mg Cu(N0 3 ) 2 -2.5H 2 0, 16.59 mg Co(N0 3 ) 2 -6H 2 0, 14.62 mg Mg(N0 3 ) 2 -6H 2 0, 16.96 mg Zn(N0 3 ) 2 -6H 2 0, and 16.58 mg Ni(N0 3 ) 2 -6H 2 0. 1 g of B-CAM.1 were added, and the resultant slurry was stirred at ambient temperature for 60 minutes of B-CAM.1 were added, and the re sultant slurry was stirred at ambient temperature for 60 minutes. Step (c.1 ): Then, the ethanol was removed by evaporation at 50°C for 60 minutes. A solid resi due was obtained.
  • the setup consisted of the XENON-SINTERON 2000 Pulse Light sys tem, a photonic curing chamber (model: LC-915) and a XENON-UV lamp (model: LH-810/910). The following parameters were applied: the distance to the lamp (10 mm), the duration of con tinuous irradiation (75 s) before the interruption for cooling (120 s), the pulse length (20 ms) and the power of the UV-lamp (2070 J), 6 repetitions.
  • the outer surface of the core material (B-CAM.1 ) contained a layer of an oxide of Li, Mg, Co, Ni, Cu and Zn.
  • a 5-ml-glass vial was charged with 0.48 ml of an ethanolic solution containing 8.34 mg LiN0 3 , 12.59 mg Mg(N0 3 ) 2 -6H 2 0, 14.29 mg Co(N0 3 ) 2 -6H 2 0, 14.28 mg Ni(N0 3 ) 2 -6H 2 0, 11.42 mg CU(N0 3 ) 2 -2.5H 2 0. and 14.61 mg Zn(N0 3 ) 2 -6H 2 0. 1 g of B-CAM.1 were added, and the resultant slurry was stirred at ambient temperature for 60 minutes.
  • Step (c.2) Then, the ethanol was removed by evaporation at 50°C for 60 minutes. A solid resi due was obtained.
  • Step (d.2) The solid residue from step (c.2) was exposed to electromagnetic radiation, wave length 200 to 1400 nm.
  • the setup consisted of the XENON-SINTERON 2000 Pulse Light sys tem, a photonic curing chamber (model: LC-915) and a XENON-UV lamp (model: LH-810/910). The following parameters were applied: the distance to the lamp (10 mm), the duration of con tinuous irradiation (75 s) before the interruption for cooling (120 s), the pulse length (20 ms) and the power of the UV-lamp (2070 J), 6 repetitions.
  • Step (e.2) The obtained solid powder from step (d.2) was calcined in air at 600 °C for 1 hour, with a heating rate of 5K/min. CAM.2 was obtained.
  • the outer surface of the core material (B- CAM.1 ) contained a layer of an oxide of Li, Mg, Co, Ni, Cu and Zn. III. Cathode and coin cell manufacture
  • the cathode slurries necessary for cathode preparation were prepared by first mixing a 7.5 wt% binder solution of polyvinylidene difluoride (PVDF, Solef 5130, Solvay) in /V-methyl-2- pyrrolidone (NMP, 3 99.5%, Merck KGaA) with conductive carbon black (Super C65, TIMCAL Ltd.) and NMP in a planetary centrifugal mixer (ARE-250, Thinky) for 3 min at 2000 rpm fol lowed by 3 min at 400 rpm After the first mixing, the either B-CAM.1 , CAM.1 or CAM:2 was added to the slurry in an open mixing cup was used.
  • PVDF polyvinylidene difluoride
  • NMP V-methyl-2- pyrrolidone
  • conductive carbon black Super C65, TIMCAL Ltd.
  • ARE-250 planetary centrifugal mixer
  • the mixture was then stirred again for 3 min at 2000 rpm and 3 min at 500 rpm, yielding a homogenous deep black slurry.
  • a motorized film applicator (MTI Corporation, MSK-AFA-II-VC-FH Tape Casting Coater )
  • the slur ry was then immediately coated on 0.03 mm thick aluminum foil using a blade film applicator with a slit height of 140 pm for B-CAM.1 , CAM.1 , or CAM.2 to obtain areal loadings of ⁇ 1-2 mgc AM -crrr 2 .
  • the obtained tapes were dried at 120 °C in vacuo for 12 hours.
  • CR2032 coin cells were assembled in an argon-filled glovebox (H 2 0 ⁇ 0.5 ppm and 0 2 ⁇ 0.5 ppm) and comprised an CAM cathode (13 mm diameter), a GF/D glass microfiber separator (17 mm diameter; GE Healthcare Life Science, Whatman), a lithium metal anode (15 mm diameter), and 100 mI of electrolyte, consisting of 1 .0 M LipF 6 in 3:7 EC:DEC by weight.
  • Long-term cycling test The first cycle involved galvanostatic cycling at 0.2C in a voltage window between 2.8-4.3 V, followed by a long-term cycling at 1C in the same voltage range.

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Abstract

Process for making a coated electrode active material wherein said process comprises the following steps: (a) providing an electrode active material according to general formula Li1+xTM1-xO2, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, optionally, at least one metal selected from Al, Mg, Ti and Zr, and x is in the range of from zero to 0.2, (b) contacting said electrode active material with a solution of salts of M2 wherein M2 is a combination of metals that includes Co, Cu, Ni, Zn and Mg, at a temperature in the range of from 5°C to 85°C, (c) removing the solvent from step (b), thereby obtaining a solid residue, (d) exposing the solid residue from step (c) to 3 to 10 pulses of electromagnetic radiation with a wavelength in the range of from 200 to 1400 nm, wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds, (e) heat-treating the material so obtained in an oxygen-containing atmosphere at a temperature in the range of from 300 to 750 °C for 10 minutes to 4 hours.

Description

Process for making a coated cathode active material, and coated cathode active material
The present invention is directed towards a process for making a coated electrode active mate rial wherein said process comprises the following steps:
(a) providing an electrode active material according to general formula Lii+xTMi-x02, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, optionally, at least one metal selected from Al, Mg, Ti and Zr, and x is in the range of from zero to 0.2,
(b) contacting said electrode active material with a solution of salts of M2 wherein M2 is a combination of metals that includes Co, Cu, Ni, Zn and Mg, at a temperature in the range of from 5°C to 85°C,
(c) removing the solvent from step (b), thereby obtaining a solid residue,
(d) exposing the solid residue from step (c) to 3 to 10 pulses of electromagnetic radiation with a wavelength in the range of from 200 to 1400 nm, wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds,
(e) heat-treating the material so obtained in an oxygen-containing atmosphere at a tempera ture in the range of from 300 to 750 °C for 10 minutes to 4 hours.
In addition, the present invention is directed towards Ni-rich electrode active materials.
Lithium ion secondary batteries are modern devices for storing energy. Many application fields have been and are contemplated, from small devices such as mobile phones and laptop com puters through car batteries and other batteries for e-mobility. Various components of the batter ies have a decisive role with respect to the performance of the battery such as the electrolyte, the electrode materials, and the separator. Particular attention has been paid to the cathode materials. Several materials have been suggested, such as lithium iron phosphates, lithium co balt oxides, and lithium nickel cobalt manganese oxides. Although extensive research has been performed the solutions found so far still leave room for improvement.
Currently, a certain interest in so-called Ni-rich electrode active materials may be observed, for example electrode active materials that contain 75 mole-% or more of Ni, referring to the total TM content.
One problem of lithium ion batteries - especially of Ni-rich electrode active materials - is at tributed to undesired reactions on the surface of the electrode active materials. Such reactions may be a decomposition of the electrolyte or the solvent or both. It has thus been tried to protect the surface without hindering the lithium exchange during charging and discharging. Examples are attempts to coat the electrode active materials with, e.g., aluminium oxide or calcium oxide, see, e.g., US 8,993,051. Other theories link undesired reactions to free LiOH or U2CO3 on the surface. Attempts have been made to remove such free LiOH or L12CO3 by washing the electrode active material with water, see, e.g., JP 4,789,066 B, JP 5,139,024 B, and US2015/0372300. However, in some instances it was observed that the properties of the resultant electrode active materials did not improve.
It was an objective of the present invention to provide a process for making electrode active materials with excellent electrochemical properties. It was also an objective to provide and es pecially so-called Ni-rich electrode active materials with excellent electrochemical properties.
Accordingly, the process defined at the outset has been found, hereinafter also referred to as “inventive process”. The inventive process comprises at least three steps, step (a), step (b) and step (c). Said steps are described in more detail below.
Step (a) includes providing an electrode active material according to general formula Lii+xTMi-xC>2, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, preferably Ni and a combination of Co and Mn or Ni and a combination of Co and Al, and, optionally, at least one metal selected from Mg, Ti and Zr, and x is in the range of from zero to 0.2, preferably 0.01 to 0.05. Preferably, at least 60 mol-% of TM is nickel.
In one embodiment of the present invention the particulate material has an average particle di ameter (D50) in the range of from 3 to 20 pm, preferably from 5 to 16 pm. The average particle diameter can be determined, e. g., by light scattering or LASER diffraction. The particles are usually composed of agglomerates from primary particles, and the above particle diameter re fers to the secondary particle diameter.
In one embodiment of the present invention, the particulate material has a specific surface, hereinafter also “BET surface” in the range of from 0.1 to 1 .5 m2/g. The BET surface may be determined by nitrogen adsorption after outgassing of the sample at 200 °C for 30 minutes or more and beyond this accordance with DIN ISO 9277:2010.
In one embodiment of the present invention, TM corresponds to general formula (I a)
(NiaCObMnc)i-dMd (l a) with a + b + c = 1 and a being in the range of from 0.6 to 0.99, preferably from 0.75 to 0.95, more preferably from 0.85 to 0.95, b being zero or in the range of from 0.025 to 0.2, preferably from 0.05 to 0.1 , c being in the range of from 0.025 to 0.2, preferably from 0.05 to 0.1 , d being in the range of from zero to 0.1 , preferably from zero to 0.04,
M is at least one of Al, Mg, Ti, and Zr, preferably at least one of Al, Ti, and Zr.
In one embodiment of the present invention, M is Al, and d is in the range of from 0.01 to 0.05.
In another embodiment of the present invention, the variable TM corresponds to general formu la (I b)
(NiaCObMnc)i-dMd (l b) with a + b + c = 1 and a being in the range of from 0.3 to 0.4, b being in the range of from zero to 0.1 , c being in the range of from 0.6 to 0.7, and d being in the range of from zero to 0.1 ,
M is Al or Ti or Zr or Mg, and a + b + c = 1 .
The variable x for Lii+xTMi-x02 and TM corresponding to formula (I b) is preferably in the range of from 0.05 to 0.2, more preferably from 0.1 to 0.15.
In one embodiment of the present invention, TM is selected from Nio.6Coo.2Mn0.2, Nio. Coo.2Mno.i, Nio.eCoo.iMno.i, Ni0.83Co0.12Mn0.05, Ni0.89Co0.055AI0.055, Ni0.91Co0.045AI0.045 and Ni0.85Co0.1Mn0.05· The electrode active material provided in step (a) is usually free from conductive carbon, that means that the conductive carbon content of starting material is less than 1% by weight, refer ring to said starting material, preferably 0.001 to 1 .0 % by weight and even more below detec tion level.
Some elements are ubiquitous. In the context of the present invention, traces of ubiquitous met als such as sodium, calcium, iron or zinc, as impurities will not be taken into account in the de scription of the present invention. Traces in this context will mean amounts of 0.02 mol-% or less, referring to the total metal content of the starting material. Traces of sulfate are neglected as well.
The electrode active material provided in step (a) may have has a moisture content in the range of from 5 to 1 ,500 ppm, preferably 10 to 1 ,200 ppm, ppm being parts per million (weight).
In step (b), said electrode active material is contacted with a solution of salts of M2 wherein M2 is a combination of metals that includes Co, Cu, Ni, Zn and Mg in one or more sub-steps, prefera bly in one step. Said solution may be a solution in an alcohol such as methanol or ethanol. In other embodiments, said solution is an aqueous solution. Said contacting is preferably a slurry ing.
Preferably, salts of M2 are selected from salts that have a minimum solubility of 25 g/l in the respective solvent - alcohol or water - at ambient temperature, preferably a minimum solubility of 50 g/l.
In one embodiment of the present invention, M2 additionally includes at least one of lithium and Fe and V.
Examples are sulfates and halides such as chlorides and bromides, furthermore nitrates and acetates. Sulfates may lead to non-volatile residues, and halides such as chlorides are unde sired in various types of electrochemical cells. In step (b), nitrates and acetates are preferred, nitrates being more preferred.
In one embodiment of the present invention, wherein molar ratio of metals other than Li, if appli cable, in M2 is in each case the same or deviates by at most 10 mol-%, preferably by at most 5 mol-%. In one embodiment of the present invention, the total molar ratio of M2 to TM is in the range of from 0.1 to 5%, preferably 1 to 5%.
In one embodiment of the present invention, the molar ratio of lithium to the molar ratio of all the metals other than Li in M2 is in the range of from 1 :2 to 1 :3.
In one embodiment of the present invention, the concentration of M2 in the solution of salts is in the range of from 0.5 to 1 mol/l, preferably 0.6 to 1 mol/l.
In one embodiment of step (b), the volume ratio of the solution of salts of M2 to electrode active material provided in step (a) is in the range of from 3:1 to 1 :3.
Step (b) is performed at a temperature in the range of from 5°C to 85°C, preferably 15 to 40 °C.
In one embodiment of the present invention, the duration of step (b) is in the range of from 10 minutes to 5 hours, preferably from 30 to 90 minutes.
In one embodiment of the present invention, step (b) is supported by mixing operation, for ex ample stirring. On laboratory scale, mixing with a magnetic stirrer is feasible.
Step (b) may be performed at any pressure but ambient pressure is preferred.
Step (b) may be performed in one step or in two or more sub-steps, one single step being pre ferred. Sub-steps may include a subsequent addition of single components of M2.
After step (b), step (c) is performed. Step (c) includes removal of the solvent, especially water, as well as removal of volatile by-products such as nitric acid or acetic acid, if applicable, prefer ably by evaporation. The conditions under which such solvent is evaporated depends on its vol atility. The temperature may be in the range of from 50 to 150 °C, and the pressure may be in the range of from 1 mbar to 1 bar (abs).
A solid residue is obtained that is subsequently subjected to step (d). In step (d), the residue obtained from step (c) is exposed to electromagnetic radiation with a wavelength in the range of from 200 to 1400 nm. In one embodiment of the present invention, step (d) is performed at a temperature in the range of from 5°C to 85°C, preferably 15 to 40 °C. It is observed that during step (d) the residue heats up, for example to 200°C or even more.
In one embodiment of the present invention, the duration of step (b) is in the range of from 10 minutes to 5 hours, preferably from 30 to 90 minutes.
In one embodiment of the present invention, step (d) is supported by mixing operation, for ex ample stirring. On laboratory scale, mixing with a magnetic stirrer is feasible.
In one embodiment of the present invention, step (d) is performed in the form of exposing the residue from step (c) to 3 to 10 pulses of electromagnetic radiation with a wavelength from 200 to 1400 nm in the form of several pulses wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds. A pulse has a duration in the range of from 1 ms to 2 sec onds, preferably 10 ms to 50 ms, and the number of pulses is in the range of from 3 to 10, pref erably 4 to 7. The distance of the residue from step (c) to the source of radiation is preferably in the range of from 5 to 15 mm.
In one embodiment of the present invention, the various pulses are about identical in duration.
In step (e) of the inventive process, the material so obtained is heat-treated in an oxygen- containing atmosphere at a temperature in the range of from 300 to 750 °C for 10 minutes to 4 hours.
Step (e) may be carried out in any type of oven, for example a roller hearth kiln, a pusher kiln, a rotary kiln, a pendulum kiln, or - for lab scale trials - in a muffle oven.
The temperature of the thermal treatment according to step (e) may be in the range of from 300 to 750 °C, preferably 350 to 650 °C. Said temperature refers to the maximum temperature of step (e).
In one embodiment of the present invention, the temperature is ramped up before reaching the desired temperature of from 300 to 750 °C. For example, first the material resulting from step (d) is heated to a temperature to 75 to 90 °C and then held constant for a time of 10 min to 0.5 hours, and then it is raised to 300 to 750 °C. In one embodiment of the present invention, the heating rate in step (e) is in the range of from 0.1 to 10 °C/min.
In one embodiment of the present invention, step (e) is performed in a roller hearth kiln, a push er kiln or a rotary kiln or a combination of at least two of the foregoing. Rotary kilns have the advantage of a very good homogenization of the material made therein. In roller hearth kilns and in pusher kilns, different reaction conditions with respect to different steps may be set quite easily. In lab scale trials, box-type and tubular furnaces and split tube furnaces are feasible as well.
In one embodiment of the present invention, step (e) is performed in an oxygen-containing at mosphere, for example in a nitrogen-air mixture, in a rare gas-oxygen mixture, in air, in oxygen or in oxygen-enriched air or in pure oxygen. In a preferred embodiment, the atmosphere in step (e) is selected from air, oxygen and oxygen-enriched air. Oxygen-enriched air may be, for ex ample, a 50:50 by volume mix of air and oxygen. Other options are 1 :2 by volume mixtures of air and oxygen, 1 :3 by volume mixtures of air and oxygen, 2:1 by volume mixtures of air and oxygen, and 3:1 by volume mixtures of air and oxygen. Pure oxygen is even more preferred.
In one embodiment of the present invention, step (e) has a duration in the range of from 10 minutes to 4 hours. Preferred are 60 minutes to 3 hours. The cooling time is neglected in this context.
By carrying out the inventive process, coated electrode active materials are obtained with excel lent electrochemical properties. Without wishing to be bound by any theory, we assume that by the sequence of steps as disclosed above, a high entropy oxide of M2 is formed that is enriched at the surface of the primary particles of the compound of general formula Lii+xTMi-x02.
They show excellent electrochemical properties.
A further aspect of the present invention is related to particulate materials, hereinafter also re ferred to as inventive cathode active materials or inventive particulate materials or inventive coated particulate materials.
Inventive particulate cathode active materials comprise a core material according to general formula Lii+xiTMi-xi02 wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, optionally, at least one metal selected from Al, Mg, Ti and Zr, and x1 is in the range of from -0.02 to 0.2, wherein the outer surface of the core material contains an oxide compound of M2 wherein M2 contains Co, Cu, Ni, Zn and Mg. Said outer surface may hereinafter also be referred to as coating.
The variable x1 may be somewhat smaller than x because of Li removal in the course of the M2 treatment process.
Inventive coated particulate materials in the context with the present invention refer to at least 80% of the particles of a batch of particulate material being coated, and to at least 75% of the surface of each particle being coated, for example 75 to 99.99 % and preferably 80 to 90%.
The thickness of such coating may be very low, for example 0.1 to 5 nm. In other embodiments, the thickness may be in the range of from 6 to 15 nm. In further embodiments, the thickness of such coating is in the range of from 16 to 50 nm.
In one embodiment of the present invention the inventive coated particulate material has an average particle diameter (D50) in the range of from 3 to 20 pm, preferably from 5 to 16 pm.
The average particle diameter can be determined, e. g., by light scattering or LASER diffraction. The particles are usually composed of agglomerates from primary particles, and the above par ticle diameter refers to the secondary particle diameter.
In one embodiment of the present invention, the inventive coated particulate material has a specific surface, hereinafter also “BET surface” in the range of from 0.1 to 1 .5 m2/g. The BET surface may be determined by nitrogen adsorption after outgassing of the sample at 200 °C for 30 minutes or more and beyond this accordance with DIN ISO 9277:2010.
In one embodiment of the present invention, said coating comprises a compound selected from an oxide of M2 and a sub-stoichiometrically lithiated oxide of M2.
In one embodiment of the present invention, the molar ratio of metals other than Li, if applicable, in M2 is in each case the same or deviates by at most 10 mol-%, preferably by at most 5%.
In one embodiment of the present invention, TM is a combination of metals according to general formula (I a)
(NiaCObMnc)i-dMd (l a) with a being in the range of from 0.6 to 0.95, b being in the range of from 0.025 to 0.2, c being in the range of from 0.025 to 0.2, and d being in the range of from zero to 0.1 ,
M is Al or Zr or Ti or Mg, and a + b + c = 1 .
In another embodiment of the present invention, the variable TM corresponds to general formu la (I b)
(NiaCObMnc)i-dMd (I b) with a + b + c = 1 and a being in the range of from 0.3 to 0.4, b being in the range of from zero to 0.1 , c being in the range of from 0.6 to 0.7, and d being in the range of from zero to 0.1 ,
M is Al or Ti or Zr or Mg, and a + b + c = 1 .
Inventive cathode active materials may be obtained by the inventive process. Without wishing to be bound by any theory, it is assumed that a high entropy oxide of M2 is formed that is enriched at the surface of the primary particles of the compound of general formula Lii+xTMi-x02.
Inventive cathode active materials display excellent properties especially with respect to cycling stability and low capacity fade.
A further aspect of the present invention refers to electrodes comprising at least one electrode active material according to the present invention. They are particularly useful for lithium ion batteries. Lithium ion batteries comprising at least one electrode according to the present inven tion exhibit a good discharge behavior. Electrodes comprising at least one electrode active ma- terial according to the present invention are hereinafter also referred to as inventive cathodes or cathodes according to the present invention.
Specifically, inventive cathodes contain
(A) at least one inventive electrode active material,
(B) carbon in electrically conductive form,
(C) a binder material, also referred to as binders or binders (C), and, preferably,
(D) a current collector.
In a preferred embodiment, inventive cathodes contain
(A) 80 to 98 % by weight inventive electrode active material,
(B) 1 to 17 % by weight of carbon,
(C) 1 to 15 % by weight of binder material, percentages referring to the sum of (A), (B) and (C).
Cathodes according to the present invention can comprise further components. They can com prise a current collector, such as, but not limited to, an aluminum foil. They can further comprise conductive carbon and a binder.
Cathodes according to the present invention contain carbon in electrically conductive modifica tion, in brief also referred to as carbon (B). Carbon (B) can be selected from soot, active carbon, carbon nanotubes, graphene, and graphite, and from combinations of at least two of the forego ing.
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, catalytic or free-radical (co)polymerization, especially from polyethylene, polyacrylo nitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth)acrylonitrile and 1 ,3-butadiene. Polypropylene is also suita ble. Polyisoprene and polyacrylates are additionally suitable. Particular preference is given to polyacrylonitrile.
In the context of the present invention, polyacrylonitrile is understood to mean not only polyacry lonitrile homopolymers but also copolymers of acrylonitrile with 1 ,3-butadiene or styrene. Pref erence is given to polyacrylonitrile homopolymers. In the context of the present invention, polyethylene is not only understood to mean homopoly ethylene, but also copolymers of ethylene which comprise at least 50 mol-% of copolymerized ethylene and up to 50 mol-% of at least one further comonomer, for example a-olefins such as propylene, butylene (1 -butene), 1 -hexene, 1 -octene, 1 -decene, 1 -dodecene, 1 -pentene, and also isobutene, vinylaromatics, for example styrene, and also (meth)acrylic acid, vinyl acetate, vinyl propionate, CrCio-alkyl esters of (meth)acrylic acid, especially methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and also maleic acid, maleic anhydride and itaconic anhydride. Polyethylene may be HDPE or LDPE.
In the context of the present invention, polypropylene is not only understood to mean homopol ypropylene, but also copolymers of propylene which comprise at least 50 mol-% of copolymer ized propylene and up to 50 mol-% of at least one further comonomer, for example ethylene and a-olefins such as butylene, 1 -hexene, 1 -octene, 1 -decene, 1 -dodecene and 1 -pentene. Pol ypropylene is preferably isotactic or essentially isotactic polypropylene.
In the context of the present invention, polystyrene is not only understood to mean homopoly mers of styrene, but also copolymers with acrylonitrile, 1 ,3-butadiene, (meth)acrylic acid, Ci- Cio-alkyl esters of (meth)acrylic acid, divinylbenzene, especially 1 ,3-divinylbenzene, 1 ,2- diphenylethylene and a-methylstyrene.
Another preferred binder (C) is polybutadiene.
Other suitable binders (C) are selected from polyethylene oxide (PEO), cellulose, carbox- ymethylcellulose, polyimides and polyvinyl alcohol.
In one embodiment of the present invention, binder (C) is selected from those (co)polymers which have an average molecular weight Mw in the range from 50,000 to 1 ,000,000 g/mol, pref erably to 500,000 g/mol.
Binder (C) may be selected from cross-linked or non-cross-linked (co)polymers.
In a particularly preferred embodiment of the present invention, binder (C) is selected from hal- ogenated (co)polymers, especially from fluorinated (co)polymers. Halogenated or fluorinated (co)polymers are understood to mean those (co)polymers which comprise at least one (co)polymerized (co)monomer which has at least one halogen atom or at least one fluorine at om per molecule, more preferably at least two halogen atoms or at least two fluorine atoms per molecule. Examples are polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, pol- yvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymers, vinylidene fluoride-hexafluoropropylene copolymers (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymers, perfluoroalkyl vinyl ether copolymers, ethylene-tetrafluoroethylene copolymers, vinylidene fluoride-chlorotrifluoroethylene copolymers and ethylene-chlorofluoroethylene copol ymers.
Suitable binders (C) are especially polyvinyl alcohol and halogenated (co)polymers, for example polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvi nyl fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.
Inventive cathodes may comprise 1 to 15% by weight of binder(s), referring to electrode active material. In other embodiments, inventive cathodes may comprise 0.1 up to less than 1% by weight of binder(s).
A further aspect of the present invention is a battery, containing at least one cathode comprising inventive electrode active material, carbon, and binder, at least one anode, and at least one electrolyte.
Embodiments of inventive cathodes have been described above in detail.
Said anode may contain at least one anode active material, such as carbon (graphite), T1O2, lithium titanium oxide, silicon or tin. Said anode may additionally contain a current collector, for example a metal foil such as a copper foil.
Said electrolyte may comprise at least one non -aqueous solvent, at least one electrolyte salt and, optionally, additives.
Non-aqueous solvents for electrolytes can be liquid or solid at room temperature and is prefera bly selected from among polymers, cyclic or acyclic ethers, cyclic and acyclic acetals and cyclic or acyclic organic carbonates.
Examples of suitable polymers are, in particular, polyalkylene glycols, preferably poly-Ci-C4- alkylene glycols and in particular polyethylene glycols. Polyethylene glycols can here comprise up to 20 mol-% of one or more Ci-C4-alkylene glycols. Polyalkylene glycols are preferably poly alkylene glycols having two methyl or ethyl end caps. The molecular weight Mw of suitable polyalkylene glycols and in particular suitable polyethylene glycols can be at least 400 g/mol.
The molecular weight Mw of suitable polyalkylene glycols and in particular suitable polyethylene glycols can be up to 5 000 000 g/mol, preferably up to 2 000 000 g/mol.
Examples of suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether,
1 ,2-dimethoxyethane, 1 ,2-diethoxyethane, with preference being given to 1 ,2-dimethoxyethane.
Examples of suitable cyclic ethers are tetrahydrofuran and 1 ,4-dioxane.
Examples of suitable acyclic acetals are, for example, dimethoxymethane, diethoxymethane,
1 ,1 -dimethoxyethane and 1 ,1 -diethoxyethane.
Examples of suitable cyclic acetals are 1 ,3-dioxane and in particular 1 ,3-dioxolane.
Examples of suitable acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.
Examples of suitable cyclic organic carbonates are compounds according to the general formu lae (II) and (III) where R1, R2 and R3 can be identical or different and are selected from among hydrogen and Ci-C4-alkyl, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert- butyl, with R2 and R3 preferably not both being tert-butyl.
In particularly preferred embodiments, R1 is methyl and R2 and R3 are each hydrogen, or R1, R2 and R3 are each hydrogen. In another embodiment, R1 is fluorine and R2 and R3 are each hy drogen. Another preferred cyclic organic carbonate is vinylene carbonate, formula (IV).
The solvent or solvents is/are preferably used in the water-free state, i.e. with a water content in the range from 1 ppm to 0.1% by weight, which can be determined, for example, by Karl-Fischer titration.
Electrolyte further comprises at least one electrolyte salt. Suitable electrolyte salts are, in partic ular, lithium salts. Examples of suitable lithium salts are LiPF6, LiBF , LiCIC , LiAsF6, UCF3SO3, LiC(CnF2n+iS02)3, lithium imides such as LiN(CnF2n+iS02)2, where n is an integer in the range from 1 to 20, LiN(S02F)2, Li2SiF6, LiSbF6, LiAICU and salts of the general formula (CnF2n+iS02)tYLi, where m is defined as follows: t = 1 , when Y is selected from among oxygen and sulfur, t = 2, when Y is selected from among nitrogen and phosphorus, and t = 3, when Y is selected from among carbon and silicon.
Preferred electrolyte salts are selected from among LiC(CF3S02)3, LiN(CF3S02)2, LiPF6, LiBF4, UCI04, with particular preference being given to LiPF6 and LiN(CF3S02)2.
In one embodiment of the present invention, batteries according to the invention comprise one or more separators by means of which the electrodes are mechanically separated. Suitable separators are polymer films, in particular porous polymer films, which are unreactive toward metallic lithium. Particularly suitable materials for separators are polyolefins, in particular film forming porous polyethylene and film-forming porous polypropylene.
Separators composed of polyolefin, in particular polyethylene or polypropylene, can have a po rosity in the range from 35 to 45%. Suitable pore diameters are, for example, in the range from 30 to 500 nm.
In another embodiment of the present invention, separators can be selected from among PET nonwovens filled with inorganic particles. Such separators can have porosities in the range from 40 to 55%. Suitable pore diameters are, for example, in the range from 80 to 750 nm. Batteries according to the invention further comprise a housing which can have any shape, for example cuboidal or the shape of a cylindrical disk or a cylindrical can. In one variant, a metal foil configured as a pouch is used as housing.
Batteries according to the invention display a good discharge behavior, for example at low tem peratures (zero °C or below, for example down to -10 °C or even less), a very good discharge and cycling behavior.
Batteries according to the invention can comprise two or more electrochemical cells that com bined with one another, for example can be connected in series or connected in parallel. Con nection in series is preferred. In batteries according to the present invention, at least one of the electrochemical cells contains at least one cathode according to the invention. Preferably, in electrochemical cells according to the present invention, the majority of the electrochemical cells contains a cathode according to the present invention. Even more preferably, in batteries according to the present invention all the electrochemical cells contain cathodes according to the present invention.
The present invention further provides for the use of batteries according to the invention in ap pliances, in particular in mobile appliances. Examples of mobile appliances are vehicles, for example automobiles, bicycles, aircrafts or water vehicles such as boats or ships. Other exam ples of mobile appliances are those which move manually, for example computers, especially laptops, telephones or electric hand tools, for example in the building sector, especially drills, battery-powered screwdrivers or battery-powered staplers.
The present invention is further illustrated by the following working examples.
Average particle diameters (D50) were determined by dynamic light scattering (“DLS”). Per centages are % by weight unless specifically noted otherwise.
LiOH-hbO was purchased from Rockwood Lithium.
The manufacture of base electrode active materials was performed in a box furnace, type: VMK-80-S, Linn High Term.
Methanol and toluene were pre-dried according to standard laboratory methods.
Unless otherwise stated, all synthesis steps were performed in a glovebox (MB200B, MBraun) under argon atmosphere with oxygen and water concentrations below 0.1 ppm. I. Manufacture of base electrode active materials
1.1 Manufacture of a precursor, P-CAM.1 , TM = Ni0.85Co0.10Mn0.05
The precipitation reaction was performed at 55°C under a nitrogen atmosphere using a continu ous stirred tank reactor with a volume of 2.3 I. The continuous stirred tank reactor was charged with 1 .5 I of the above aqueous solution of (NH )2SC>4. Then, the pH value of the solution was adjusted to 11 .5 using a 25% by weight aqueous solution of sodium hydroxide. An aqueous metal solution containing N1SO4, C0SO4 and MnS04 (molar ratio 85:10:5, total metal concentra tion: 1 .65 mol/kg), aqueous sodium hydroxide (25wt% NaOH) and aqueous ammonia solution (25wt% ammonia) were simultaneously introduced into the vessel. The molar ratio between ammonia and metal was adjusted to 0.265. The sum of volume flows was set to adjust the mean residence time to 5 hours. The flow rate of the NaOH was adjusted by a pH regulation circuit to keep the pH value in the vessel at a constant value of 11 .58. The apparatus was oper ated continuously keeping the liquid level in the vessel constant. A mixed hydroxide of Ni, Co and Mn was collected via free overflow from the vessel. The resulting product slurry contained about 120g/l mixed hydroxide of Ni, Co and Mn with an average particle size (D50) of 10.5 pm, P-CAM.1.
1.2 Manufacture of B-CAM.1
Step (a.1 ): Subsequently, P-CAM.1 was mixed with LiOH-H20 at a molar ratio of Li : TM of
I .02:1 and calcined at 780 °C with a dwell time of 10 hours in a flow of pure oxygen. The heat ing rate was 3 °C/min. Particulate B-CAM.1 was obtained and sieved using a mash size of 32 pm. Karl-Fischer titration showed the moisture content to be below detection level, 50 ppm.
II. Synthesis of inventive cathode active materials
11.1 Synthesis of inventive cathode active material CAM.1
Step (b.1 ):
A 5-ml-glass vial was charged with 48 ml of an ethanolic solution containing 13.26 mg Cu(N03)2-2.5H20, 16.59 mg Co(N03)2-6H20, 14.62 mg Mg(N03)2-6H20, 16.96 mg Zn(N03)2-6H20, and 16.58 mg Ni(N03)2-6H20. 1 g of B-CAM.1 were added, and the resultant slurry was stirred at ambient temperature for 60 minutes of B-CAM.1 were added, and the re sultant slurry was stirred at ambient temperature for 60 minutes. Step (c.1 ): Then, the ethanol was removed by evaporation at 50°C for 60 minutes. A solid resi due was obtained.
Step (d.1 ): The solid residue from step (c.1 ) was exposed to electromagnetic radiation, wave length 200 to 1400 nm. The setup consisted of the XENON-SINTERON 2000 Pulse Light sys tem, a photonic curing chamber (model: LC-915) and a XENON-UV lamp (model: LH-810/910). The following parameters were applied: the distance to the lamp (10 mm), the duration of con tinuous irradiation (75 s) before the interruption for cooling (120 s), the pulse length (20 ms) and the power of the UV-lamp (2070 J), 6 repetitions.
Step (e.1 ): The obtained solid powder from step (d.1 ) was calcined in air at 600 °C for 1 h, with a heating rate of 5K/min. CAM.1 was obtained. The outer surface of the core material (B-CAM.1 ) contained a layer of an oxide of Li, Mg, Co, Ni, Cu and Zn.
11.2 Synthesis of inventive cathode active material CAM.2
Step (b.2):
A 5-ml-glass vial was charged with 0.48 ml of an ethanolic solution containing 8.34 mg LiN03, 12.59 mg Mg(N03)2-6H20, 14.29 mg Co(N03)2-6H20, 14.28 mg Ni(N03)2-6H20, 11.42 mg CU(N03)2-2.5H20. and 14.61 mg Zn(N03)2-6H20. 1 g of B-CAM.1 were added, and the resultant slurry was stirred at ambient temperature for 60 minutes.
Step (c.2): Then, the ethanol was removed by evaporation at 50°C for 60 minutes. A solid resi due was obtained.
Step (d.2): The solid residue from step (c.2) was exposed to electromagnetic radiation, wave length 200 to 1400 nm. The setup consisted of the XENON-SINTERON 2000 Pulse Light sys tem, a photonic curing chamber (model: LC-915) and a XENON-UV lamp (model: LH-810/910). The following parameters were applied: the distance to the lamp (10 mm), the duration of con tinuous irradiation (75 s) before the interruption for cooling (120 s), the pulse length (20 ms) and the power of the UV-lamp (2070 J), 6 repetitions.
Step (e.2): The obtained solid powder from step (d.2) was calcined in air at 600 °C for 1 hour, with a heating rate of 5K/min. CAM.2 was obtained. The outer surface of the core material (B- CAM.1 ) contained a layer of an oxide of Li, Mg, Co, Ni, Cu and Zn. III. Cathode and coin cell manufacture
111.1 Cathode manufacture
General procedure:
The cathode slurries necessary for cathode preparation were prepared by first mixing a 7.5 wt% binder solution of polyvinylidene difluoride (PVDF, Solef 5130, Solvay) in /V-methyl-2- pyrrolidone (NMP, ³ 99.5%, Merck KGaA) with conductive carbon black (Super C65, TIMCAL Ltd.) and NMP in a planetary centrifugal mixer (ARE-250, Thinky) for 3 min at 2000 rpm fol lowed by 3 min at 400 rpm After the first mixing, the either B-CAM.1 , CAM.1 or CAM:2 was added to the slurry in an open mixing cup was used. The mixture was then stirred again for 3 min at 2000 rpm and 3 min at 500 rpm, yielding a homogenous deep black slurry. Using a motorized film applicator (MTI Corporation, MSK-AFA-II-VC-FH Tape Casting Coater ), the slur ry was then immediately coated on 0.03 mm thick aluminum foil using a blade film applicator with a slit height of 140 pm for B-CAM.1 , CAM.1 , or CAM.2 to obtain areal loadings of ~1-2 mgcAM-crrr2. The obtained tapes were dried at 120 °C in vacuo for 12 hours.
111.2 Coin cell manufacture
CR2032 coin cells were assembled in an argon-filled glovebox (H20 < 0.5 ppm and 02 < 0.5 ppm) and comprised an CAM cathode (13 mm diameter), a GF/D glass microfiber separator (17 mm diameter; GE Healthcare Life Science, Whatman), a lithium metal anode (15 mm diameter), and 100 mI of electrolyte, consisting of 1 .0 M LipF6 in 3:7 EC:DEC by weight.
Test protocol:
In general, for every experiment, at least three cells were successfully cycled and results are shown as the average of these cells. They were cycled with a battery testing system (Landt Po- tentiostat; Landt International Inc.) at 25 °C.
C-rate test:
The first cycle involved galvanostatic charging to 4.3 V at a rate of 0.1 C, with 1 C = 200 mA g-1 for B-CAM.1 , C-CAM.1 and C-CAM.2. After reaching the voltage limit, the cell was discharged to 2.8 V at 0.1 C rate and then rested for 5 min. After this initial cycle, a rate test followed with five cycle each at 0.5C, 1 C, 2C, 3C, 5C, 10C, 2C, and 0.5C for charging and discharging in a voltage rage between 2.8-4.3 V. Long-term cycling test: The first cycle involved galvanostatic cycling at 0.2C in a voltage window between 2.8-4.3 V, followed by a long-term cycling at 1C in the same voltage range.
Table 1 : Electrochemistry: C-Rate results
Table 2: Electrochemistry: long-term cycling results

Claims

Patent Claims
1 . Process for making a coated electrode active material wherein said process comprises the following steps:
(a) providing an electrode active material according to general formula Lii+xTMi-x02, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, option ally, at least one metal selected from Al, Mg, Ti and Zr, and x is in the range of from zero to 0.2,
(b) contacting said electrode active material with a solution of salts of M2 wherein M2 is a combination of metals that includes Co, Cu, Ni, Zn and Mg,
(c) removing the solvent from step (b), thereby obtaining a solid residue,
(d) exposing the solid residue from step (c) to 3 to 10 pulses of electromagnetic radia tion with a wavelength in the range of from 200 to 1400 nm, wherein the duration of the pulses is in the range of from 1 milliseconds to 2 seconds,
(e) heat-treating the material so obtained in an oxygen-containing atmosphere at a tem perature in the range of from 300 to 750 °C for 10 minutes to 4 hours.
2. Process according to claim 1 wherein TM is a combination of metals according to general formula (I a) or (I b)
(NiaCObMnc)i dM1d (I a) with a being in the range of from 0.6 to 0.99, b being in the range of from 0.025 to 0.2, c being in the range of from 0.025 to 0.2, and d being in the range of from zero to 0.1 ,
M1 is Al or Zr or Ti or Mg, and a + b + c = 1 .
(NiaCObMnc)i-dM1d (I b) with a being in the range of from 0.3 to 0.4, b being in the range of from zero to 0.1 , c being in the range of from 0.6 to 0.7, and d being in the range of from zero to 0.1 ,
M is Al or Ti or Zr or Mg, and a + b + c = 1 .
3. Process according to claim 1 or 2 wherein M2 additionally includes at least one of Li, Fe, and V.
4. Process according to any of the preceding claims wherein the salts of M2 are selected from acetates and nitrates.
5. Process according to any of the preceding claims wherein the molar ratio of metals other than Li, if applicable, in M2 is in each case the same or deviates by at most 10 mol-%.
6. Process according to any of the preceding claims wherein step (b) is performed in the presence of water.
7. Process according to any of the preceding claims wherein the molar ratio of M2 is 0.1 to 5%, referring to TM.
8. Particulate cathode active material comprising a core material according to general formu la Lii+xiTMi-xiC>2, wherein TM is Ni or a combination of Ni and at least one of Co and Mn, and, optionally, at least one metal selected from Al, Mg, Ti and Zr, and x1 is in the range of from -0.02 to 0.2, wherein the outer surface of the core material contains an oxide com pound of M2 wherein M2 contains Co, Cu, Ni, Zn and Mg.
9. Particulate material according to claim 8 wherein said coating comprises a compound selected from an oxide of M2 and a sub-stoichiometrically lithiated oxide of M2.
10. Particulate material according to claim 8 or 9 wherein TM is a combination of metals ac cording to general formula (I a) or (I b)
(NiaCObMnc)i-dMd (I a) with a being in the range of from 0.6 to 0.99, b being in the range of from 0.025 to 0.2, c being in the range of from 0.025 to 0.2, and d being in the range of from zero to 0.1 ,
M is Al or Zr or Ti or Mg, and a + b + c = 1 ,
(NiaCObMnc)i-dMd (I b) with a being in the range of from 0.3 to 0.4, b being in the range of from zero to 0.1 , c being in the range of from 0.6 to 0.7, and d being in the range of from zero to 0.1 ,
M is Al or Ti or Zr or Mg, and a + b + c = 1 .
11 . Particulate material according to any of claims 8 to 10 wherein M2 additionally includes at least one of Fe, V, and Li.
12. Particulate material according to any of claims 8 to 11 wherein the molar ratio of metals other than Li, if applicable, in M2 is in each case the same or deviates by at most 10 mol-
%.
13. Particulate material according to any of claims 8 to 10 wherein oxide compounds of M2 are enriched in the outer shell of secondary particles of said material.
14. Cathode comprising
(A) at least one particulate material according to any of the claims 8 to 13,
(B) carbon in electrically conductive form, and
(C) a binder polymer.
15. Electrochemical cell comprising at least one cathode according to claim 14.
EP22733935.5A 2021-07-09 2022-06-14 Process for making a coated cathode active material, and coated cathode active material Pending EP4367726A1 (en)

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