A multi-step method for manufacturing cathode active material, and cathode active material

Abstract

Provided is a Ni-rich electrode active material having excellent electrochemical properties. 【Solution means】General formula (Li a Mg b ) 1+x (Ni c M 1 d ) 1-x O2 (In the formula, M 1 is selected from Al, Zr, Co, Mn, Nb, Ta, Mo and W, a:b is in the range of 40:1 to 200:1, and a + b = 1, c:d is in the range of 50:1 to 250:1, and c + d = 1, The total molar ratio of (Li + Mg) and (TM + M 1 ) is in the range of 1:1 to 1.05:1, 0.00 ≦ x ≦ 0.05) provides a particulate electrode active material.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a cathode active material, wherein the method comprises the following steps: (a) A step of providing a hydroxide TM(OH)2, or at least one oxide TMO, or an oxyhydroxide of at least one TM, or a combination of at least two of the above, wherein TM is one or more metals, and contains at least 97 mol% Ni and optionally at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, and Mn in a total of 3 mol% or less. (b) A step of mixing the hydroxide TM(OH)2, or oxide TMO, or oxyhydroxide of TM, or a combination thereof, with a lithium source and a Mg source, wherein the molar amount of (Li+Mg) corresponds to 75-95 mol% of TM. (c) A step of heat-treating the mixture obtained from step (b) at a temperature in the range of 450 to 650°C to obtain an intermediate, (d) The intermediate from step (c) is obtained from a Li source and a metal M selected from Al, Zr, Co, Mn, Nb, Ta, Mo and W. 1 A step of mixing with at least one compound, (e) A step of heat-treating the mixture obtained from step (d) at a temperature in the range of 500 to 850°C. Includes. [Background technology]

[0002] Lithium-ion secondary batteries are state-of-the-art devices for energy storage. Many application fields have been considered, from small devices such as mobile phones and laptop computers to car batteries and other batteries for e-mobility. Various battery components, such as electrolytes, electrode materials, and separators, play important roles regarding battery performance. Cathode materials are particularly in the spotlight. Several materials, such as lithium iron phosphate, lithium cobalt oxide, and lithium nickel cobalt manganese oxide, have been proposed. Extensive research has been conducted, but the solutions found so far still have room for improvement.

[0003] Currently, a particular interest is observed in so-called Ni-rich (high Ni content) electrode active materials, for example, electrode active materials containing 75 mol% or more of Ni with respect to the total TM content.

[0004] A particular Ni-rich material is LiNiO₂ (often abbreviated as LNO). However, pure LNO has various drawbacks and the interest in commercial use has been declining. Among these drawbacks, the most important ones are the tendency to deviate from the stoichiometry of Li (Li 1-z Ni 1+z O₂), and the various instability problems in its delithiated state, which can be (electro)chemical, mechanical, or thermal properties, making the synthesis of stoichiometric LiNiO₂ difficult. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] An object of the present invention was to provide a method for manufacturing a Ni-rich electrode active material having excellent electrochemical characteristics, particularly a good capacity retention rate. Another object of the present invention was to provide a Ni-rich electrode active material having excellent electrochemical characteristics. MEANS FOR SOLVING THE PROBLEMS

[0006] Therefore, the method defined at the beginning, also referred to below as the method of the present invention, was found. The method of the present invention consists of the following steps: (a) A step of providing a hydroxide TM(OH)2, or at least one oxide TMO, or an oxyhydroxide of at least one TM, or a combination of at least two of the above, wherein TM is one or more metals, and contains at least 97 mol% Ni and optionally at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, and Mn in a total of 3 mol% or less. (b) A step of mixing the hydroxide TM(OH)2, or oxide TMO, or oxyhydroxide of TM, or a combination thereof, with a lithium source and a Mg source, wherein the molar amount of (Li+Mg) corresponds to 75-95 mol% of TM. (c) A step of heat-treating the mixture obtained from step (b) at a temperature in the range of 450 to 650°C to obtain an intermediate, (d) The intermediate from step (c) is obtained from a Li source and a metal M selected from Al, Zr, Co, Mn, Nb, Ta, Mo and W. 1 A step of mixing with at least one compound, (e) A step of heat-treating the mixture obtained from step (d) at a temperature in the range of 500 to 850°C. Includes. [Modes for carrying out the invention]

[0007] Accordingly, the method of the present invention comprises five steps (a), (b), (c), (d), and (e), which are also referred to as steps (a), (b), (c), (d), and (e) respectively in the context of the present invention. Preferably, these five steps are carried out sequentially.

[0008] The method of the present invention starts with a hydroxide TM(OH)2, or at least one oxide TMO, or an oxyhydroxide of at least one TM, or a combination of at least two of the above. In such a hydroxide TM(OH)2, or at least one oxide TMO, or oxyhydroxide of TM, TM contains at least 99 mol% Ni and optionally at least one metal selected from Ti, Zr, V, Co, Zn, Ba, and Mn in a total of 3 mol% or less, preferably 1 mol% or less. More preferably, TM contains at least 99.5 mol% Ni, and optionally at least one metal selected from Ti, Zr, and Co in a total of 0.5 mol% or less, and trace amounts of V, Zn, Ba, and Mn. Even more preferably, TM is Ni. The amount and type of metal such as Ti, Zr, V, Co, Zn, Ba, and Mn may be determined by inductively coupled plasma ("ICP") and synchrotron XRD.

[0009] The TM(OH)2 or TMO or TM oxyhydroxide provided in step (a) preferably consists of spherical particles, which refer to particles having a spherical shape. The spherical particles include not only perfectly spherical particles but also particles in which the maximum and minimum diameters differ by 10% or less in at least 90% (number mean) of the representative sample.

[0010] In one embodiment of the present invention, the oxyhydroxide of TM(OH)2, TMO, or TM provided in step (a) is composed of secondary particles which are aggregates of primary particles. Preferably, the oxyhydroxide of TM(OH)2, TMO, or TM provided in step (a) is composed of spherical secondary particles which are aggregates of primary particles. More preferably, the oxyhydroxide of TM(OH)2, TMO, or TM provided in step (a) is composed of spherical primary particles or spherical secondary particles which are aggregates of platelets.

[0011] In one embodiment of the present invention, the TM(OH)2 or TMO or TM oxyhydroxide provided in step (a) has an average particle size (D50) in the range of 3 to 20 μm, preferably 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of aggregates of primary particles, and the above particle size refers to the particle size of the secondary particles.

[0012] Some elements are ubiquitous. In the context of this invention, trace amounts of ubiquitous metals such as sodium, calcium, or zinc as impurities are not considered in the specification of this invention. In this context, "trace amount" means an amount of 0.02 mol% or less relative to the total metal content of the starting material.

[0013] In one embodiment of the present invention, TM contains 3 mol% or less of Ti, Zr, V, Co, Zn, Ba, or Mn, and at least one metal selected from the above combination of at least two, with Al and Zr being preferred. The Ti, Zr, V, Co, Zn, Ba, or Mn, and the above combination of at least two may be uniformly distributed in the Ni(OH)2 or NiO or nickel oxyhydroxide particles, or concentrated on the surface, with a uniform distribution being preferred.

[0014] The TM(OH)2 provided in step (a) can be produced by precipitating Ni and, where applicable, at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, or Mn in a total of 3 mol% or less from an aqueous solution of nickel sulfate containing, optionally, a compound of at least one of the aforementioned metals (one or more) selected from Al, Ti, Zr, V, Co, Zn, Ba, or Mn, with an alkali metal hydroxide, followed by filtration and drying.

[0015] The oxyhydroxides of TMO and TM provided in step (a) can be produced by heating TM(OH)2 and thereby removing water.

[0016] The term 'TM' refers to oxyhydroxides that contain water chemically bonded as hydroxides, or non-stoichiometric oxyhydroxides that have residual water.

[0017] In step (b), the hydroxide TM(OH)2 or oxide TMO or oxyhydroxide or combination of TM provided in step (a) is mixed with a lithium source and a Mg source, where the molar amount of (Li + Mg) corresponds to 75 to 95 mol% of TM.

[0018] Examples of lithium sources are inorganic lithium compounds, such as LiNO3, Li2O, LiOH, and Li2CO3, with Li2O, LiOH, and Li2CO3 being preferred, crystallized water being negligible in the context of lithium sources, and LiOH being even more preferred.

[0019] In one embodiment of the present invention, the lithium source has an average particle size (D50) in the range of 1 to 5 μm.

[0020] Examples of Mg sources include magnesium nitrate, MgO, MgCO3, Mg(HCO3)2, and Mg(OH)2, with MgO and Mg(OH)2 being preferred, and crystallization water being negligible in the context of magnesium sources. Mg(OH)2 is even more preferred.

[0021] In one embodiment of the present invention, the magnesium source has an average particle size (D50) in the range of 50 nm to 1 μm, which can be determined by dynamic light scattering.

[0022] In one embodiment of step (b), a source of Al, Zr, Co, Mn, Nb, Ta, Mo, or W is also added. Preferred sources of Al, Zr, Co, Mn, Nb, Ta, Mo, or W will be described further below.

[0023] In one embodiment of step (b), the molar ratio of Li to Mg is in the range of 200:1 to 25:1, and preferably 100:1 to 30:1.

[0024] Step (b) can be carried out as a single operation, but it is preferable that step (b) includes a sub-step of mixing TM(OH)2 or TMO or a combination of TM oxyhydroxides with the lithium source, and then a sub-step of adding a solution of the magnesium source. The sub-steps are described in more detail below. However, it is preferable to carry out step (b) in a single step, or to first perform a sub-step (b1) of mixing the lithium source and the magnesium source, and then a sub-step (b2) of combining the resulting mixture with a TM(OH)2 or a combination of TM oxyhydroxides with TMO.

[0025] Step (b) can be carried out by mixing each component in a mixer, such as a plowshaar mixer or tumble mixer. In laboratory-scale experiments, ball mills and roller mills can also be used.

[0026] Step (b) can be carried out by adding water or an organic solvent, but it is preferable not to add an organic solvent or water in sub-step (b) or any sub-step.

[0027] The preferred duration of process (b) is in the range of 1 minute to 60 minutes.

[0028] In step (b), a mixture is obtained.

[0029] Sub-step (b1) can be carried out by mixing the lithium source and the magnesium source in a mixer, such as a plow shear mixer or tumble mixer. In laboratory-scale experiments, a ball mill and roller mill can also be used. A mixture is obtained from sub-step (b1). Sub-step (b2) is carried out following sub-step (b1). In sub-step (b2), a hydroxide TM(OH)2 or TMO or oxyhydroxide or combination of TM is added to the mixture from sub-step (b1).

[0030] Sub-steps (b1) and (b2) can be carried out by adding water or an organic solvent, but it is preferable not to add an organic solvent or water in sub-step (b1). The preferred duration of sub-steps (b1) and (b2) is in the range of 1 minute to 30 minutes.

[0031] While it is possible to carry out sub-step (b) under heating, it is preferable not to perform additional heating during step (b).

[0032] In one embodiment of the present invention, step (b) is performed at atmospheric pressure. However, it is preferable to perform step (b) at high pressure, for example, at a pressure 10 to 10 bar higher than atmospheric pressure, or at a pressure 50 to 250 millibars lower than atmospheric pressure, preferably 100 to 200 millibars lower than atmospheric pressure, while suction is applied.

[0033] In one embodiment of the present invention, step (b) is carried out by filling a container with TM(OH)2 or an oxide TMO or TM oxyhydroxide, a lithium source, and then the Mg source.

[0034] In one embodiment of the present invention, an aluminum source is also added in step (b). Suitable sources include, for example, Al(NO3)3, Al2O3, Al(OH)3, AlOOH, and Al2O3·aq, with AlOOH and Al2O3, particularly γ-Al2O3, being preferred. The aluminum source can be added as an aqueous solution, an aqueous slurry, or in particulate form, with particulate form being preferred.

[0035] In one embodiment of the present invention, the Al source has an average particle size (D50) in the range of 0.5 to 5 μm, which can be determined by dynamic light scattering.

[0036] In one embodiment of the present invention, the amount of Al source is such that the molar ratio of Mg to Al is in the range of 5:1 to 1:5.

[0037] Step (c) includes heat-treating the mixture obtained from step (b) at a temperature in the range of 450 to 650°C, preferably 475 to 575°C.

[0038] Step (c) can be carried out in any type of oven, such as a roller hearth kiln, pusher kiln, rotary kiln, pendulum kiln, or, in the case of laboratory-scale testing, a muffle oven.

[0039] The temperature range of 450-650°C corresponds to the maximum temperature in process (c).

[0040] The mixture obtained in step (b) can be directly applied to step (c). However, it is preferable to increase the temperature in steps or gradually. The stepwise or gradual temperature increase can be carried out under normal pressure or reduced pressure, for example, 1 to 500 millibars.

[0041] The process (c) at the highest temperature can be carried out under normal pressure.

[0042] Step (c) is carried out in an oxygen-containing atmosphere, for example, oxygen-enriched air containing at least 80 volume percent oxygen, or under pure oxygen.

[0043] In one embodiment of the present invention, steps (b) and (c) are carried out in an atmosphere having a reduced CO2 content, for example, a carbon dioxide content in the range of 0.01 to 500 ppm by mass, preferably 0.1 to 50 ppm by mass. The CO2 content can be determined, for example, by an optical method using infrared light. It is even more preferable to carry out step (c) in an atmosphere having a carbon dioxide content below the detection limit by an optical method based on infrared light, for example.

[0044] In one embodiment of the present invention, step (c) is carried out in a roller hearth kiln, a pusher kiln, or a rotary kiln, or a combination of at least two of the above. The rotary kiln has the advantage of providing very good homogenization of the material produced therein. In roller hearth kilns and pusher kilns, different reaction conditions for different steps can be set very easily. In laboratory-scale experiments, box furnaces, tubular furnaces, and segmented tubular furnaces can also be used.

[0045] In one embodiment of the present invention, step (c) is carried out under a forced flow of a gas, such as air, oxygen, and oxygen-enriched air. Such a gas flow is sometimes called a forced gas flow. Such a gas flow is 0.5 to 15 m³ per 1 kg of mixture from step (b). 3 It can have a specific flow rate in the range of / h. The volume is determined under normal conditions (298 Kelvin and 1 atmosphere). The forced gas flow is useful for removing gaseous cleavage products such as water.

[0046] In one embodiment of the present invention, step (c) has a duration in the range of 2 to 30 hours, preferably 10 to 24 hours. In the context of the present invention, cooling time is negligible.

[0047] An intermediate is obtained from step (c). Preferably, the intermediate is cooled to room temperature.

[0048] Step (d) involves obtaining the intermediate from step (c) from a Li source and a metal M selected from Al, Co, Mn, Nb, Ta, Mo, Zr, W and at least two combinations of the above. 1 This includes mixing with at least one compound of the following. Al, Co, Zr, and a combination of at least two of the above are preferred. 1 The compound may be a nitrate or a halide, but oxides, hydroxides, and oxyhydroxides are preferred.

[0049] In one embodiment of the present invention, M 1The molar ratio of TM is in the range of 1:33 to 1:500, preferably 1:50 to 1:250. The molar ratio is the total molar ratio, and when at least two elements M 1 are selected, it refers to all elements M 1 .

[0050] Examples of the lithium source in step (d) are the same as those in step (b). Therefore, inorganic compounds of lithium such as LiNO3, Li2O, LiOH, and Li2CO3 are used. Li2O, LiOH, and Li2CO3 are preferred. The water of crystallization is ignored in the context of the lithium source, and LiOH is even more preferred in both steps (b) and (d).

[0051] Examples of the Al source are Al(NO3)3, Al2O3, Al(OH)3, AlOOH, and Al2O3·aq. Al(OH)3, AlOOH, and Al2O3, particularly γ - Al2O3, are preferred.

[0052] Examples of the Co source are Co(NO3)2, Co(OH)2, CoO, CoCO3, Co3O4, and Co2O3. Co(OH)2, CoO, Co3O4, and Co2O3 are preferred.

[0053] Examples of the Mn source are MnCO3 and MnO2. MnO2 is preferred.

[0054] Examples of the Nb source are Nb2O3, Nb2O5, niobic acid, and Nb2O5·H2O. In the case of niobic acid, the amount of water is not necessarily stoichiometric.

[0055] Examples of the Ta source are Ta, Ta2O3, and Ta2O5.

[0056] Examples of the Mo source are Mo, MoO3, and Li2MoO4.

[0057] Examples of the W source are W, WO3, and Li2WO4.

[0058] Examples of the Zr source are ZrO2, ZrO(OH)2, and Zr(OH)4.

[0059] In one embodiment of the present invention, M 1 The average diameter (D50) of the source is preferably in the range of 10 nm to 100 μm, and more preferably in the range of 20 nm to 20 μm. Preferably, so-called nanoparticle-like M having an average diameter (D50) in the range of 10 nm to 50 nm, as measured by laser diffraction or dynamic light scattering ("DLS"). 1 Oxides or hydroxides of M, and generally having an average diameter (D50) of, for example, 100 nm to 2 μm. 1 These are oxides or hydroxides of [unclear material]. Nanometals such as Ta, Mo, and W, having an average diameter (D50) in the range of 10 to 50 nm, are also preferred.

[0060] The stoichiometry in process (d) is (Li + Mg) and (TM + M 1 The total molar ratio of ) may be selected to be in the range of 1:1 to 1.05:1.

[0061] The mixing can be carried out simultaneously with step (b), with the necessary modifications.

[0062] Step (e) includes heat-treating the mixture obtained from step (d) at a temperature in the range of 500 to 850°C.

[0063] Step (e) can be carried out in any type of oven, such as a roller hearth kiln, pusher kiln, rotary kiln, pendulum kiln, or, in the case of laboratory-scale testing, a muffle oven.

[0064] The temperature range of 500-850°C corresponds to the maximum temperature of process (e).

[0065] The mixture obtained in step (d) can be directly applied to step (e). However, it is preferable to increase the temperature in steps or gradually. The stepwise or gradual temperature increase can be carried out under normal pressure or reduced pressure, for example, 1 to 500 millibars.

[0066] The process (e) at the highest temperature can be carried out under normal pressure.

[0067] Step (e) is carried out in an oxygen-containing atmosphere, for example, oxygen-enriched air containing at least 80 volume percent oxygen, or under pure oxygen.

[0068] In one embodiment of the present invention, step (e) has a duration in the range of 2 to 30 hours, preferably 6 to 24 hours. In the context of the present invention, cooling time is negligible.

[0069] The temperature intervals for steps (c) and (e) overlap. In one embodiment of the present invention, the temperature of step (e) is higher than the temperature of step (c), for example, by at least 50°C. In an embodiment in which step (c) is performed at 600°C or more specifically at 650°C, step (e) is performed at a temperature of preferably 650-800°C or 700-800°C, respectively.

[0070] By performing step (e), an electrode active material is obtained. The intermediate is preferably cooled to room temperature.

[0071] The method of the present invention may further include any optional steps, such as deaggregation after step (c) or (e) or both, or a washing step with water to remove any residual lithium that may be present as an unreacted base following step (e).

[0072] By performing the method of the present invention, an electrode active material with excellent electrochemical properties can be obtained. Although we do not wish to be bound by any theory, we assume that magnesium is incorporated into the lithium layer.

[0073] Further aspects of the present invention relate to an electrode active material, also referred to below as the electrode active material of the present invention. The electrode active material of the present invention is in particle form and has the general formula (Li a Mg b ) 1+x (TM c M 1 d ) 1-xIt has O2, where TM contains at least 97 mol% Ni and optionally 3 mol% or less of at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba or Mn. M 1 The element is selected from Al, Co, Mn, Nb, Ta, Mo, and W. a:b is in the range of 40:1 to 200:1, and a+b=1. c:d is in the range of 50:1 to 250:1, and c+d=1. 0.00 <x≦0.05であり、したがって、(Li+Mg)と(TM+M 1 The total molar ratio of ) is in the range of 1:1 to 1.05:1.

[0074] Preferably, TM contains at least 99 mol% Ni and optionally at least one metal selected from Al, Ti, Zr, Co, V, Zn, Ba, and Ca in a total of 1.0 mol% or less. More preferably, TM contains at least 99.5 mol% Ni and optionally at least one metal selected from Ti, Zr, and Co in a total of 0.5 mol% or less, and trace amounts of V, Zn, Ba, and Mn. Even more preferably, TM is Ni.

[0075] In one embodiment of the present invention, TM contains at least 99 mol% Ni and at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, or Mn in total amount of 1 mol% or less, wherein the Al, Ti, Zr, V, Co, Zn, Ba, or Mn, or a combination of at least two of the above, may be uniformly distributed in the Ni(OH)2 particles or concentrated on the surface, with a uniform distribution being preferred.

[0076] Preferably, Ni is Ni, or Ti, Zr, V, Co, Zn, Ba, or Mn are uniformly distributed in TM, and M 1 It is coated on the outer surface or exhibits a concentration gradient.

[0077] In one embodiment of the present invention, the electrode active material of the present invention has an average particle size (D50) in the range of 3 to 20 μm, preferably 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of aggregates of primary particles, and the above particle size refers to the particle size of the secondary particles.

[0078] In one embodiment of the present invention, the electrode active material of the present invention is determined according to DIN-ISO 9277:2003-05, and is 0.1 to 2.0 m 2 It has a specific surface area (BET) in the range of / g.

[0079] Further aspects of the present invention relate to electrodes comprising at least one electrode active material according to the present invention. These are particularly useful in lithium-ion batteries. A lithium-ion battery comprising at least one electrode according to the present invention exhibits good discharge behavior. An electrode comprising at least one electrode active material according to the present invention is hereinafter also referred to as the cathode of the present invention or the cathode according to the present invention.

[0080] In particular, the cathode of the present invention is (A) At least one electrode active material of the present invention, (B) Conductive carbon, (C) Binder material, also called binder or binder(C), and preferably (D) Current collector It contains.

[0081] In a preferred embodiment, the cathode of the present invention is based on the sum of (A), (B), and (C), (A) 80-98% by mass of the electrode active material of the present invention, (B) 1-17% by mass of carbon, (C) Binder material in 1-15% by mass It contains.

[0082] The cathode according to the present invention may include further components, which may include current collectors, such as aluminum foil (but not limited to this). They may further include conductive carbon and a binder.

[0083] The cathode according to the present invention contains conductively modified carbon, also abbreviated as carbon(B). Carbon(B) can be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite, and at least two combinations thereof.

[0084] A suitable binder (C) is preferably selected from organic (co)polymers. Suitable (co)polymers, i.e., homopolymers or copolymers, can be selected from (co)polymers that can be obtained by anionic (co)polymerization, catalytic (co)polymerization or free radical (co)polymerization, particularly from copolymers of polyethylene, polyacrylonitrile, polybutadiene, polystyrene, and at least two comonomers selected from ethylene, propylene, styrene, (meth)acrylonitrile, and 1,3-butadiene. Polypropylene is also suitable. Polyisoprene and polyacrylate are even more suitable. Polyacrylonitrile is particularly preferred.

[0085] 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. Polyacrylonitrile homopolymers are preferred.

[0086] In the context of the present invention, polyethylene means not only homopolyethylene but also at least 50 mol% copolymerized ethylene and 50 mol% or less of at least one further comonomer, such as α-olefins, such as propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, and also isobutene, vinyl aromatics, such as styrene, and also (meth)acrylic acid, vinyl acetate, vinyl propionate, and C1-C of (meth)acrylic acid.10 -Alkyl esters, particularly methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and copolymers of ethylene containing maleic acid, maleic anhydride, and itaconic anhydride. Polyethylene may be HDPE or LDPE.

[0087] In the context of the present invention, polypropylene is understood to mean not only homopolypropylene but also copolymers of propylene comprising at least 50 mol% copolymerized propylene and at least one further comonomer of 50 mol% or less, such as ethylene, and α-olefins, such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene, and 1-pentene. Polypropylene is preferably isotactic polypropylene or essentially isotactic polypropylene.

[0088] In the context of the present invention, polystyrene refers not only to styrene homopolymers, but also to acrylonitrile, 1,3-butadiene, (meth)acrylic acid, and C1-C of (meth)acrylic acid. 10 -It is understood to also mean copolymers with alkyl esters, divinylbenzene, particularly 1,3-divinylbenzene, 1,2-diphenylethylene, and α-methylstyrene.

[0089] Another preferred binder (C) is polybutadiene.

[0090] Other suitable binders (C) are selected from polyethylene oxide (PEO), cellulose, carboxymethylcellulose, polyimide, and polyvinyl alcohol.

[0091] In one embodiment of the present invention, the binder (C) has an average molecular weight M in the range of 50,000 g / mol to 1,000,000 g / mol, preferably up to 500,000 g / mol. WSelected from (co)polymers having the following properties.

[0092] The binder (C) may be a crosslinked or uncrosslinked (co)polymer.

[0093] In particularly preferred embodiments of the present invention, the binder (C) is selected from halogenated (co)polymers, particularly fluorinated (co)polymers. Halogenated or fluorinated (co)polymers are understood to mean (co)polymers comprising 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.

[0094] Suitable binders (C) include, in particular, polyvinyl alcohol and halogenated (co)polymers, such as polyvinyl chloride or polyvinylidene chloride, and especially fluorinated (co)polymers, such as polyvinyl fluoride and especially polyvinylidene fluoride and polytetrafluoroethylene.

[0095] The cathode of the present invention may contain 1 to 15% by mass of a binder (one or more) relative to the electrode active material. In other embodiments, the cathode of the present invention may contain 0.1 to less than 1% by mass of a binder (one or more).

[0096] A further aspect of the present invention is a battery comprising the electrode active material of the present invention, carbon, and a binder, comprising at least one cathode, at least one anode, and at least one electrolyte.

[0097] Embodiments of the cathode of the present invention have already been described in detail above.

[0098] The anode may contain at least one anode active material, such as carbon (graphite), TiO2, lithium titanium oxide, silicon, or tin. The anode may further contain a current collector, such as a metal foil, such as copper foil.

[0099] The electrolyte may include at least one non-aqueous solvent, at least one electrolyte salt, and optionally an additive.

[0100] The non-aqueous solvent for the electrolyte may be liquid or solid at room temperature and is preferably selected from polymers, cyclic or acyclic ethers, cyclic and acyclic acetals, and cyclic or acyclic organic carbonates.

[0101] Examples of suitable polymers include, in particular, polyalkylene glycols, preferably poly-C1-C4 alkylene glycols, and especially polyethylene glycols. Here, polyethylene glycol may contain up to 20 mol% of one or more C1-C4 alkylene glycols. The polyalkylene glycol is preferably a polyalkylene glycol having two methyl or ethyl terminal caps.

[0102] A suitable polyalkylene glycol, particularly a polyethylene glycol, has a molecular weight M W It can be at least 400 g / mol.

[0103] A suitable polyalkylene glycol, particularly a polyethylene glycol, has a molecular weight M W This can be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol.

[0104] Examples of suitable acyclic ethers include, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane, and 1,2-diethoxyethane, with 1,2-dimethoxyethane being preferred.

[0105] Suitable examples of cyclic ethers are tetrahydrofuran and 1,4-dioxane.

[0106] Suitable examples of acyclic acetals include, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane, and 1,1-diethoxyethane.

[0107] Suitable examples of cyclic acetals are 1,3-dioxane and, in particular, 1,3-dioxolane.

[0108] Suitable examples of acyclic organic carbonates include dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

[0109] Suitable examples of cyclic organic carbonates are compounds of general formulas (II) and (III). [ka] (In the formula, R 1 , R 2 and R 3 These can be the same or different, and are selected from hydrogen and C1-C4 alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, preferably R 2 and R 3 (Neither of them can be tert-butyl.)

[0110] In a particularly preferred embodiment, R 1 is methyl, and R 2 and R 3 Each of them is either hydrogen or R 1 , R 2 and R 3Each of these is hydrogen.

[0111] Another preferred cyclic organic carbonate is the vinylene carbonate of formula (IV).

[0112] [ka]

[0113] Preferably, the solvent or a plurality of solvents are used in a water-free state, i.e., with a water content in the range of 1 ppm to 0.1% by mass, which can be determined, for example, by Karl Fischer titration.

[0114] The electrolyte (C) further comprises at least one electrolyte salt. Preferred electrolyte salts are lithium salts in particular. Examples of preferred lithium salts are LiPF6, LiBF4, LiClO4, LiAsF6, LiCF3SO3, and 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 in the range of 1 to 20), LiN(SO2F)2, Li2SiF6, LiSbF6, LiAlCl4, and the general formula (C n F 2n+1 SO2) t YLi salt (In the formula, when Y is selected from oxygen and sulfur, t=1, When Y is selected from nitrogen and phosphorus, t=2, (If Y is selected from carbon and silicon, then t=3)

[0115] Preferred electrolyte salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, and LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred.

[0116] In embodiments of the present invention, the battery according to the present invention includes one or more separators by which electrodes are mechanically separated. Preferred separators are polymer films that do not react with metallic lithium, particularly porous polymer films. Particularly preferred materials for the separators are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0117] Separators made of polyolefins, particularly polyethylene or polypropylene, can have a porosity in the range of 35-45%. Suitable pore sizes are, for example, in the range of 30-500 nm.

[0118] In another embodiment of the present invention, the separator can be selected from a PET nonwoven fabric filled with inorganic particles. Such a separator may have a porosity in the range of 40-55%. A suitable pore size is, for example, in the range of 80-750 nm.

[0119] The battery according to the present invention further includes a housing which can have any shape, for example, a cube, or the shape of a cylindrical disk or cylindrical can. In one modified embodiment, a metal foil configured as a pouch is used as the housing.

[0120] The battery according to the present invention exhibits excellent discharge behavior, such as at low temperatures (below 0°C, even below -10°C), and very good discharge and cycle behavior.

[0121] The battery according to the present invention may include two or more electrochemical cells that are combined with each other, for example, connected in series or in parallel. 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 cell contains cathode according to the present invention. Even more preferably, in the battery according to the present invention, all electrochemical cells contain cathode according to the present invention.

[0122] The present invention further provides a method for using the battery according to the present invention in equipment, in particular mobile equipment. Examples of mobile equipment include vehicles, such as automobiles, bicycles, aircraft, or watercraft, such as boats or ships. Other examples of mobile equipment include manually operated devices, such as computers, in particular laptops, telephones, or power tools in the construction sector, such as drills, battery-powered screwdrivers, or battery-powered staplers.

[0123] The present invention will be further explained by the following embodiments. [Examples]

[0124] The average particle size (D50) was measured by dynamic light scattering ("DLS"). Unless otherwise specified, percentages are in mass percent.

[0125] LiOH·OH was purchased from Rockwood Lithium. Mg(OH)2 was purchased from Sigma Aldrich, Al2O3 from Sasol, and Zr(OH)4 from Luxfer Mel Technologies. A blender (Kinematica) was used as a mixer.

[0126] I. Production of the base cathode active material LiNiO2 I.1 Preparation of Precursors Step (a.1): Using ammonia as a complexing agent, a 1.65 mol / kg solution of nickel sulfate was combined with a 25% by mass solution of NaOH to obtain a spherical Ni(OH)2 precursor. The pH was set to 12.6. The newly precipitated Ni(OH)2 was washed with water, sieved, and dried at 120°C for 12 hours. The obtained Ni(OH)2 ("P-CAM.1") had an average particle size D50 of 10 μm.

[0127] II. Production of the cathode active material of the present invention and the cathode active material for comparison. II.1 Manufacturing of C-CAM.1 Step (b.1): 50 g of P-CAM.1 was mixed with 22.80 g of LiOH·H2O, 0.32 g of Mg(OH)2, 0.15 g of Al2O3, and 0.25 g of Zr(OH)4.

[0128] Step (c.1): Pour the resulting mixture into an alumina crucible and raise it under an oxygen atmosphere (10 exchanges / hour) until the first temperature rise reaches 10°C min. -1 , 3°C min in the second temperature rise -1 The heating was performed at a rate of 10°C to 600°C for 1 hour, and then to 700°C for 6 hours. The heat treatment was carried out using a laboratory furnace (Linn High Therm). C-CAM.1 was obtained. C-CAM.1 was heated at 10°C min -1 It was cooled to 120°C at the cooling rate and then transferred to a drying chamber for further processing.

[0129] Neither process (d) nor (e) was performed.

[0130] Next, the obtained C-CAM.1 was sieved using a mesh size of 32 μm to obtain C-CAM.1 containing 1.0 mol% Mg, 0.55 mol% Al, 0.24 mol% Zr, and a molar ratio of (Li+Mg) / (Ni+Al+Zr)=1.01.

[0131] II.2 Manufacturing of CAM.2 Step (b.2): 50 g of P-CAM.1 was mixed with 17.67 g of LiOH·H2O, 0.25 g of Mg(OH)2, and 0.15 g of Al2O3.

[0132] Step (c.2): Pour the resulting mixture into a quartz glass valve, which is part of the rotary kiln, and leave it in an oxygen atmosphere (100 exchanges / hour) at 10°C min -1 The mixture was heated to 600°C for 1 hour at a heating rate of 20 rpm. An intermediate was obtained. The obtained intermediate was heated to 10°C min. -1 The mixture was cooled to room temperature at the specified cooling rate and then transferred to a drying chamber for further processing. The composition was 63% by mass Ni, 0.13% by mass Al, 0.18% by mass Mg, and 5.51% by mass Li.

[0133] Step (d.2): Using a blender, 40 g of the intermediate from step (c.2) was mixed with 5.23 g of LiOH·H2O, 0.09 g of Mg(OH)2, and 0.21 g of Zr(OH)4. A mixture was obtained.

[0134] Step (e.2): Pour the mixture from step (d.2) into an alumina crucible and store in a laboratory furnace under an oxygen atmosphere (10 changes / hour) at 3°C ​​min. -1 The mixture was heated to 700°C for 6 hours at the following heating rate. The resulting CAM.2 was then heated to 10°C min. -1 It was cooled to 120°C at the cooling rate and then transferred to a drying chamber for further processing.

[0135] Next, CAM.2 was sieved using a 32 μm mesh size to obtain CAM.2 containing 0.70 mol% Mg, 0.45 mol% Al, 0.24 mol% Zr, and a molar ratio (Li+Mg) / (Ni+Al+Zr) = 1.02 (measured by ICP-OES).

[0136] II.3 Manufacturing of CAM.3 Step (b.3): 50 g of P-CAM.1 was mixed with 17.67 g of LiOH·H2O, 0.25 g of Mg(OH)2, and 0.15 g of Al2O3.

[0137] Step (c.3): Pour the obtained mixture into an alumina crucible and raise it under an oxygen atmosphere (10 exchanges / hour) until the first temperature rise reaches 10°C min. -1 , 3°C min in the second temperature rise -1 The mixture was heated to 600°C for 1 hour, then to 700°C for 6 hours. This heat treatment was performed using a laboratory furnace (Linn High Therm). An intermediate was obtained. The obtained intermediate was heated to 10°C min. -1 The mixture was cooled to room temperature at the specified cooling rate and then transferred to a drying chamber for further processing. The composition was 63% by mass of Ni, 0.15% by mass of Al, 0.21% by mass of Mg, and 5.79% by mass of Li.

[0138] Step (d.3): Using a blender, 40 g of the intermediate from step (c.3) was mixed with 4.37 g of LiOH·H2O, 0.06 g of Mg(OH)2, and 0.21 g of Zr(OH)4. A mixture was obtained.

[0139] Step (e.3): Pour the mixture from step (d.2) into an alumina crucible and refrigerate in a laboratory furnace under an oxygen atmosphere (10 exchanges / hour) at 3°C ​​min. -1 The mixture was heated to 700°C for 6 hours at the following heating rate. The resulting CAM.3 was then heated to 10°C min. -1 It was cooled to 120°C at the cooling rate and then transferred to a drying chamber for further processing.

[0140] Next, CAM.3 was sieved using a 32 μm mesh size to obtain CAM.3 containing 0.8 mol% Mg, 0.5 mol% Al, 0.24 mol% Zr, and a molar ratio (Li+Mg) / (Ni+Al+Zr) = 1.01 (measured by ICP-OES).

[0141] III. Electrochemistry Test III.1 Cathode Manufacturing, General Procedure: Electrode Manufacturing: The electrodes contained 94% of each CAM or C-CAM.1, 3% carbon black (Super C65), and 3% binder (polyvinylidene fluoride, Solef 5130). A slurry with 61% total solids was mixed in N-methyl-2-pyrrolidone (planetary mixer, 24 minutes, 2000 rpm) and cast onto aluminum foil tape using a box coater. The electrode tape was dried in vacuum at 120°C for 16 hours, calendered, punched out 14 mm diameter circular electrodes, weighed, dried in vacuum at 120°C for 12 hours, and then placed in a glove box filled with Ar. Average gain: 8 mg / cm 2 , Electrode density: 3g / cm 3 .

[0142] III.2 Coin Cell Manufacturing Coin-type electrochemical cells were assembled in a glove box filled with argon. The anode was made of 0.58 mm thick Li foil, separated from the cathode by a glass fiber separator (Whatman GF / D). 95 μl of 1 M LiPF6 in ethylene carbonate (EC):ethyl methyl carbonate (EMC) in a mass ratio of 3:7 was used as the electrolyte. After assembly, the cells were crimped and closed using an automatic crimping machine. The cells were then moved to an artificial climate chamber and connected to a battery cycler (Series 4000, MACCOR).

[0143] III.2 Coin Cell Test All tests were performed at 25°C. The cells were cycled at constant current using a Maccor 4000 battery cycler at room temperature (3.1–4.3V) by applying the following C rates until 70% of the initial discharge capacity was reached in a specific discharge cycle.

[0144] The test protocol consists of an initial formation phase and a speed test phase, starting with two cycles at C / 10. The voltage window was set to 3.0-4.3V throughout all cycles. The initial 1C rate was 200mA g. -1 This was assumed. In all subsequent cycles, charging was set to C / 2 and 4.3V for 30 minutes, or to CCCV until the current was less than C / 100. After discharging the cell for 5 cycles at C / 5, the discharge rate was gradually increased (C / 10, C / 5, C / 2, 1C, 2C, 3C). Subsequently, the 1C rate was matched to the capacity of 1C discharge. After rate testing, the state of charge-dependent cell resistance was determined by the DCIR method. After a short potential relaxation, 400mA g -1 A current pulse was applied for 10 seconds. Following each current pulse, the cell was discharged at C / 5 for 30 minutes, and this was repeated until the cell voltage dropped to below 3V. After this initial period, the cell was cycled alternately with 2 cycles of discharge at C / 10 and 50 cycles of discharge at 1C. In each second C / 10 cycle, the cell potential was relaxed for 5 minutes at SOCs of 100, 50, and 25%, and then 100 mA g -1A 30-second current pulse was applied, the cell resistance was calculated using the DCIR method, and the cell was discharged for 30 minutes with a 2.5C rate discharge pulse.

[0145] [Table 1]

Claims

1. A method for producing an electrode active material, wherein the method comprises the following steps: (a) Hydroxide TM (OH) ２ A step of providing, or at least one oxide TMO, or an oxyhydroxide of at least one TM, or a combination of at least two of the above, wherein TM is one or more metals, and contains at least 97 mol% Ni and optionally a total of 3 mol% or less of at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, and Mn. (b) The hydroxide TM(OH) ２ A step of mixing a lithium source and a magnesium source with an oxide TMO, or an oxyhydroxide of TM, or a combination thereof, wherein the molar amount of (Li + Mg) corresponds to 75 to 95 mol% of TM. (c) A step of heat-treating the mixture obtained from step (b) at a temperature in the range of 450 to 650°C to obtain an intermediate, (d) The intermediate from step (c) is obtained from a Li source and a metal M selected from Al, Zr, Co, Mn, Nb, Ta, Mo and W. １ A step of mixing with at least one compound, (e) A step of heat-treating the mixture obtained from step (d) at a temperature in the range of 500 to 850°C. Methods that include...

2. (Li+Mg) and (TM+M １ The method according to claim 1, wherein the total molar ratio of ) is in the range of 1:1 to 1.05:

1.

3. The method according to claim 1 or 2, wherein in step (b), the molar ratio of Li to Mg is in the range of 200:1 to 25:

1.

4. The Mg source is Mg(OH) ２ The method according to any one of claims 1 to 3, wherein the method is selected from and MgO.

5. The method according to any one of claims 1 to 4, wherein an Al source is added in step (b).

6. The method according to any one of claims 1 to 5, wherein the temperature in step (e) is higher than the temperature in step (c).

7. The method according to any one of claims 1 to 6, wherein steps (c) and (e) are carried out in an atmosphere of at least 80 volume percent oxygen.

8. M １ The method according to any one of claims 1 to 7, wherein the molar ratio of to TM is in the range of 1:50 to 1:

250.

9. General form (Li ａ Mg ｂ ) １＋ｘ (TM) ｃ M １ ｄ ) １－ｘ O ２ (wherein TM contains at least 97 mol% Ni and optionally 1 mol% or less of at least one metal selected from Ti, Al, Zr, V, Co, Zn, Ba and Mn) M １ It is selected from Al, Zr, Co, Mn, Nb, Ta, Mo, and W. a:b is in the range of 40:1 to 200:1, and a+b=1. c:d is in the range of 50:1 to 250:1, and c+d=1. (Li+Mg) and (TM+M １ The total molar ratio of ) is in the range of 1:1 to 1.05:

1. (0.00 ≤ x ≤ 0.05) Particulate electrode active material.

10. The particulate electrode active material according to claim 9, wherein TM is nickel.

11. M １ The particulate electrode active material according to claim 9 or 10, wherein the active material is Al, Co, Zr, or a combination of at least two of the above.

12. The electrode active material is composed of secondary particles which are aggregates of primary particles, M １ The particulate electrode active material according to any one of claims 9 to 11, wherein the active material is concentrated on the surface of the primary particles.

13. (A) At least one electrode active material according to any one of claims 9 to 12, (B) Conductive carbon, (C) Binder material A cathode containing this substance.

14. Based on the sum of (A), (B), and (C), (A) 80-98% by mass of cathode active material, (B) 1 to 17% by mass of carbon, (C) Binder material in a concentration of 3 to 10% by mass. A cathode according to claim 13, comprising the above.

15. An electrochemical cell comprising at least one cathode according to claim 13 or 14.

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