Method for producing electrode and electrode active material

Abstract

To provide an electrode active material and an electrochemical cell with little capacity reduction and thus high cycle stability.SOLUTION: A particulate electroactive material according to the general formula Li1 + xTM1-xO2, wherein x is in the range of from 0 to 0.1 and TM contains nickel and at least one of Co, Mn and Al; Wherein at least 25% of all particles have a crack level in the range of from 5 to 30, such cracks containing carbon in a conductive form, said crack level being determined with the help of SEM image (s) analyzed by an edge detection algorithm that calculates the gradient of the image intensity and thus detects cracks.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a method for manufacturing a semiconductor device comprising the steps of: (a) Formula Li 1+x TM 1-x providing a particulate lithiated transition metal oxide of O2, where x is in the range of 0 to 0.1, and Tm contains nickel and at least one of Co, Mn, and Al; (b) combining the lithiated transition metal oxide from step (a) with a conductive form of carbon; (c) exposing the mixture obtained in step (b) to a pressure in the range of 100 to 500 MPa for a period of 1 second to 1 minute, thereby causing cracks in at least a portion of the particles of the electrode active material; (d) mixing the mixture from step (c) with a binder polymer, optionally with additional conductive forms of carbon, and a solvent; (e) applying the mixture from step (d) to a metal foil; The present invention relates to a method for manufacturing an electrode, including:

[0002] Furthermore, the present invention relates to an electrode active material. [Background technology]

[0003] Lithiated transition metal oxides are currently used as electrode active materials in lithium-ion batteries. Extensive research and development has been conducted over the past several years to improve other properties, such as cycle life degradation and capacity loss, which adversely affect the life or applicability of lithium-ion batteries. Further efforts are being made to improve manufacturing methods.

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

[0005] To date, capacity loss remains a problem. Various theories exist as to the cause of capacity loss, including modifying the surface properties of the cathode active material by coating it with inorganic oxides or polymers. Each solution leaves room for improvement. There are various theories as to why capacity loss occurs with repeated use. One of these theories is related to crack formation, and attempts have been made to prevent crack formation, for example, by coating methods (US 2017 / 0104217), adding tungsten oxide to the interparticle voids (EP 3 553 856), or using specific co-precipitation conditions (US 2018 / 0166687). While all of the above documents teach how to avoid crack formation, they leave room for improvement. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US 2017 / 0104217 [Patent Document 2] EP 3 553 856 [Patent Document 3] US 2018 / 0166687 Summary of the Invention [Problem to be solved by the invention]

[0007] It was therefore an object of the present invention to provide an electrode with low capacity fade and therefore high cycling stability. It was also an object of the present invention to provide a method for producing such an electrode with low capacity fade and high cycling stability. It was also an object of the present invention to provide an electrode active material with low capacity fade and therefore high cycling stability. [Means for solving the problem]

[0008] We have therefore found the method defined at the outset, which in the following is also referred to as the method of the invention or the method according to the invention. [Brief explanation of the drawings]

[0009] [Figure 1] Figure 1a shows an SEM image of CAM.1. [Figure 2] Figure 1b shows an SEM image of CAM.1. [Figure 3] Figure 1c shows an SEM image of CAM.1. DETAILED DESCRIPTION OF THE INVENTION

[0010] The method of the present invention comprises the following steps (a) to (e), hereinafter also referred to as step (a) or step (b) or step (c) or step (d) or step (e), or simply (a) or (b) or (c) or (d) or (e), respectively. Steps (a) to (e) are described in more detail below.

[0011] Step (a) comprises reacting a compound of the general formula Li 1+x TM 1-x It starts with a lithiated transition metal oxide of O2 (wherein x is in the range of 0-0.1, 0-0.1, preferably 0.01-0.05, and TM contains nickel and at least one of Co, Mn, and Al).

[0012] The TM may contain trace amounts of additional metal ions, such as trace amounts of ubiquitous metals such as sodium, calcium, or zinc, as impurities, but such trace amounts are not considered within the context of this invention. Trace amounts in this context mean amounts of 0.05 mol % or less, based on the total metal content of the TM.

[0013] In one embodiment of the present invention, a compound of the general formula Li 1+x TM 1-x The lithiated transition metal oxides with O2 have an average particle size (D50) ranging from 3 to 20 μm, preferably from 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of agglomerates of primary particles, and the particle size indicated above refers to the particle size of the secondary particles.

[0014] In one embodiment of the present invention, a compound of the general formula Li 1+x TM 1-x The primary particles of the lithiated transition metal oxide with O2 have an average particle size (D50) in the range of 1 to 2000 nm, preferably 10 to 1000 nm, and particularly preferably 50 to 500 nm. The average particle size of the primary particles can be determined, for example, by SEM or TEM, or by laser scattering.

[0015] In one embodiment of the present invention, TM is represented by the general formula (I): (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.6 to 1.0, preferably 0.7 to 0.9, more preferably 0.75 to 0.85, b is in the range of 0 to 0.2, preferably 0.05 to 0.2, c is in the range of 0 to 0.2, preferably 0.01 to 0.1, d is in the range of 0 to 0.1, preferably 0.001 to 0.005; M1 is selected from Al, Ti, Zr, W, Nb, Ta, Mo, Mg, and a combination of at least two thereof, among which Al, Ti, Zr, and a combination of at least two thereof are preferred; a+b+c=1, at least one of b, c, and d is greater than 0; It is a combination of transition metals.

[0016] In one embodiment of the present invention, the lithiated transition metal oxide provided in step (a) has a concentration of 0.1 to 1.0 m 2 / g, which can be determined by nitrogen adsorption after outgassing the sample at 200°C for 30 minutes and beyond, according to DIN-ISO 9277:2003-05.

[0017] In step (b), the lithiated transition metal oxide is mixed with a conductive form of carbon, hereinafter also referred to as carbon (B). Carbon (B) can be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite. Carbon (B) can be added directly to the process of the present invention. The preferred carbon (B) is graphite.

[0018] In step (b), no binder (C) is added or is not present. The binder (C), also called binder polymer (C), is described in more detail below.

[0019] In step (b), it is preferred to mix the lithiated transition metal oxide with carbon (B), where the amount of carbon (B) is less than the amount of the lithiated transition metal oxide. Preferably, in step (b), the mass ratio of the lithiated transition metal oxide provided in step (a) to carbon (B) is in the range of 100:1 to 20:1, preferably 60:1 to 25:1.

[0020] In one embodiment of the present invention, the carbon (B) in step (b) has an average particle size in the range of 1 to 20 μm. Preferably, the carbon (B) is selected from synthetic graphite having platelet-shaped secondary particles.

[0021] In one embodiment of the present invention, the mixing in step (b) is carried out in a high shear mixer, a plowshare mixer, a free-fall mixer, or a ball mill. On a laboratory scale, shakers and roller mixers are also suitable. On a laboratory scale, a mortar with a pestle can also be used.

[0022] In step (c), the mixture obtained in step (b) is subjected to a pressure in the range of 100 to 500 MPa, preferably 120 to 350 MPa, to thereby generate cracks in at least some of the particles of the electrode active material. The crack level is in the range of 5 to 30, preferably at least 20, which refers to at least 25% of all particles of each electrode active material.

[0023] Step (c) may be carried out in various types of vessels. For example, an isostatic press is suitable. The isostatic press can be selected from so-called "cold" isostatic presses and "hot" isostatic presses, which are known from the ceramic green body forming and foundry industry. On a laboratory scale, a tablet press can also be used.

[0024] In one embodiment of the present invention, step (c) is carried out at a temperature in the range of 10 to 50° C. External cooling can be carried out during step (c). Preferably, step (c) is carried out without external heating or cooling.

[0025] The duration of step (c) is in the range of 1 second to 1 minute, preferably 5 seconds to 30 seconds.

[0026] During step (c), cracks form in the particles of the lithiated transition metal oxide. These cracks can be detected by SEM (scanning electron microscope), and the crack level is determined as follows: the SEM image is analyzed by an edge detection algorithm that calculates the gradient of the image intensity and thus detects the cracks.

[0027] Such cracks may have any shape. They follow the primary particles but do not affect them. In an alternative embodiment, the cracks may also affect the primary particles. Preferably, such cracks affect the secondary particles but not the primary particles. The cracks may only show one direction or a turn, for example, they may be zigzag.

[0028] In a next step (d), the mixture from step (c) is mixed with a binder polymer (C), optionally with a further conductive form of carbon (carbon (B)), and a solvent.

[0029] The cathode according to the present invention contains a conductively modified carbon, also referred to simply as carbon (B). Carbon (B) can be selected from soot, activated carbon, carbon nanotubes, graphene, and graphite. Carbon (B) can be added directly during the preparation of the electrode material according to the present invention.

[0030] The electrodes according to the present invention may contain further components. They may include a current collector (D), such as, but not limited to, aluminum foil. They may further include a binder polymer (C), hereinafter also referred to as binder (C). The current collector (D) will not be further described here.

[0031] Suitable binders (C) are preferably selected from organic (co)polymers. Suitable (co)polymers, i.e., homopolymers or copolymers, can be selected, for example, from (co)polymers obtainable by anionic (co)polymerization, catalytic (co)polymerization, or free-radical (co)polymerization, in particular from polyethylene, polyacrylonitrile, polybutadiene, polystyrene, and copolymers of at least two comonomers selected from ethylene, propylene, styrene, (meth)acrylonitrile, and 1,3-butadiene. Polypropylene is also suitable. Polyisoprene and polyacrylates are furthermore suitable. Polyacrylonitrile is particularly preferred.

[0032] In the context of the present invention, polyacrylonitrile is understood to mean not only polyacrylonitrile homopolymers but also copolymers of acrylonitrile with 1,3-butadiene or styrene, with polyacrylonitrile homopolymers being preferred.

[0033] In the context of the present invention, polyethylene refers not only to homopolyethylenes but also to copolymerized ethylene at least 50 mol % and up to 50 mol % of at least one further comonomer, such as α-olefins, for example propylene, butylene (1-butene), 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-pentene, and also isobutene, vinyl aromatics, for example styrene, and also (meth)acrylic acid, vinyl acetate, vinyl propionate, C1-C2 copolymers of (meth)acrylic acid. 10 -Alkyl esters, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, 2-ethylhexyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and also copolymers of ethylene with maleic acid, maleic anhydride and itaconic anhydride. Polyethylene can be HDPE or LDPE.

[0034] In the context of the present invention, polypropylene is understood to mean not only homopolypropylene but also copolymers of propylene with at least 50 mol % copolymerized propylene and up to 50 mol % of at least one further comonomer, such as ethylene, and α-olefins, such as butylene, 1-hexene, 1-octene, 1-decene, 1-dodecene and 1-pentene. The polypropylene is preferably isotactic or essentially isotactic polypropylene.

[0035] In the context of the present invention, polystyrene is not only a homopolymer of styrene, but also a C1-C6 copolymer of acrylonitrile, 1,3-butadiene, (meth)acrylic acid, 10 -alkyl esters, divinylbenzene, in particular 1,3-divinylbenzene, copolymers with 1,2-diphenylethylene and α-methylstyrene are also understood to mean.

[0036] Another preferred binder (C) is polybutadiene.

[0037] Other suitable binders (C) are selected from polyethylene oxide (PEO), cellulose, carboxymethyl cellulose, polyimides and polyvinyl alcohol.

[0038] In one embodiment of the present invention, the binder (C) has an average molecular weight M ranging from 50,000 g / mol to 1,000,000 g / mol, preferably up to 500,000 g / mol. W The (co)polymers are selected from the group consisting of:

[0039] The binder (C) may be a crosslinked or non-crosslinked (co)polymer.

[0040] In a particularly preferred embodiment of the present invention, the binder (C) is selected from halogenated (co)polymers, in particular fluorinated (co)polymers.Halogenated or fluorinated (co)polymers are understood to mean (co)polymers that contain at least one (co)polymerized (co)monomer having at least one halogen atom or at least one fluorine atom per molecule, more preferably at least two halogen atoms or at least two fluorine atoms per molecule.Examples include polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyvinylidene fluoride (PVdF), tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer (PVdF-HFP), vinylidene fluoride-tetrafluoroethylene copolymer, perfluoroalkyl vinyl ether copolymer, ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, and ethylene-chlorofluoroethylene copolymer.

[0041] Suitable binders (C) are especially polyvinyl alcohol and halogenated (co)polymers such as polyvinyl chloride or polyvinylidene chloride, especially fluorinated (co)polymers such as polyvinyl fluoride and especially polyvinylidene fluoride, and polytetrafluoroethylene.

[0042] Suitable solvents that can be added include, but are not limited to, organic aprotic solvents such as N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), dimethyl sulfoxide (DMSO), aromatic hydrocarbons such as toluene and ethylbenzene, and xylenes such as m-xylene, o-xylene, and mixtures of xylene isomers.

[0043] In a preferred embodiment of the present invention, the amounts of carbon (B) and binder polymer (C) are selected as follows: (A) 80 to 99 wt. % of the cathode active material obtained from step (c); (B) 0.5 to 19.5 mass% carbon; (C) 0.5 to 9.5 mass% of a binder polymer; The above percentages are based on the total of (A), (B) and (C).

[0044] The amount of solvent, if any, is selected to form a slurry or paste, for example, from 25% by weight to up to 10 times the total weight of the cathode active material obtained from step (c), carbon (B), and binder polymer (C).

[0045] The mixing can be carried out in any suitable vessel and is preferably carried out until a lump-free slurry or paste is obtained.

[0046] In step (e), the mixture obtained in step (e) is applied to a metal foil, such as aluminum foil, which then functions as a current collector. The application involves disposing the slurry or paste from step (d) on the metal foil, for example by spraying, dipping, using a doctor blade, or using a squeegee, so as to ensure a layer of the slurry or paste from step (d) has a uniform thickness, and removing the solvent, if applicable, by drying under reduced pressure.

[0047] Step (e) may further comprise a calendering step.

[0048] Cathodes prepared according to the methods of the present invention are excellent components for electrochemical cells, particularly lithium ion batteries.

[0049] Another aspect of the present invention relates to an electrode active material, hereinafter also referred to as the electrode active material of the present invention or the cathode active material of the present invention. The electrode material of the present invention can be produced according to the method of the present invention. The electrode material of the present invention will be described in more detail below.

[0050] The electrode material of the present invention has the general formula Li 1+x TM1-x O2 (wherein x is in the range of 0 to 0.1, preferably 0.01 to 0.05, and TM contains nickel and at least one of Co, Mn, and Al, e.g., Ni, Co, and Al, or Ni, Co, and Mn, or Ni, Mn, and Al), wherein at least 25% of all particles have a crack level of at least 5, e.g., in the range of 5 to 30, and such cracks contain carbon in a conductive form.

[0051] In one embodiment of the present invention, the electrode active material of the present invention has an average particle size (D50) in the range of 3 to 20 μm, preferably 5 to 16 μm. The average particle size can be determined, for example, by light scattering, laser diffraction, or electroacoustic spectroscopy. The particles are usually composed of aggregates of primary particles, and the above particle size refers to the particle size of secondary particles.

[0052] In one embodiment of the present invention, the primary particles of the electrode active material of the present invention have an average particle size (D50) in the range of 1 to 2000 nm, preferably 10 to 1000 nm, and particularly preferably 50 to 500 nm. The average particle size of the primary particles can be determined, for example, by SEM or TEM, or by laser scattering.

[0053] In one embodiment of the present invention, a compound of formula Li 1+x TM 1-x TM in O2 is represented by the general formula (I): (Ni a Co b Mn c ) 1-d M 1 d (I) (wherein a is in the range of 0.6 to 1.0, preferably 0.7 to 0.9, more preferably 0.75 to 0.85, b is in the range of 0 to 0.2, preferably 0.05 to 0.2, c is in the range of 0 to 0.2, preferably 0.01 to 0.1, d is in the range of 0 to 0.1, preferably 0.001 to 0.005; M 1 is selected from Al, Ti, Zr, W, Nb, Ta, Mo, Mg, and a combination of at least two thereof, among which Al, Ti, Zr, and a combination of at least two thereof are preferred; a+b+c=1), It is a combination of elements.

[0054] The electrode active material of the present invention is further characterized in that at least 25% of the particles have a crack level of at least 5, for example in the range of 5 to 30, preferably at least 20, and such cracks contain a conductive form of carbon, preferably graphite. Cracks can be detected by SEM (scanning electron microscope), and the crack level is determined as follows: each SEM image is analyzed by an edge detection algorithm that calculates the gradient of the image intensity and thus detects cracks.

[0055] In one embodiment of the present invention, the electrode active material of the present invention has a viscosity of 0.1 to 1.0 m 2 / g。 BET surface area can be determined by nitrogen adsorption after outgassing the sample at 200 ° C for 30 minutes and beyond in accordance with DIN-ISO 9277:2003-05.

[0056] In one embodiment of the present invention, the electrode active material of the present invention has a mass ratio of the provided lithiated transition metal oxide to carbon (B) in the range of 100:1 to 20:1, preferably 60:1 to 25:1.

[0057] The cracks usually do not contain the binder polymer (C).

[0058] A further aspect of the present invention is (1) A cathode comprising the electrode active material (A) of the present invention, carbon (B), and a binder (C); (2) an anode, and (3) at least one electrolyte An electrochemical cell comprising:

[0059] The embodiment of the cathode (1) is as described in detail above.

[0060] The anode (2) may contain at least one anode active material, such as carbon (graphite), TiO, lithium titanium oxide, silicon, or tin. The anode (2) may further contain a current collector, for example, a metal foil such as copper foil.

[0061] The electrolyte (3) may include at least one non-aqueous solvent, at least one electrolyte salt, and optionally an additive.

[0062] The non-aqueous solvent for the electrolyte (3) can be liquid or solid at room temperature and is preferably selected from polymers, cyclic or acyclic ethers, cyclic and acyclic acetals, and cyclic or acyclic organic carbonates.

[0063] Examples of suitable polymers are, in particular, polyalkylene glycols, preferably poly-C1-C4-alkylene glycols and especially polyethylene glycols, where the polyethylene glycols may contain up to 20 mol % of one or more C1-C4-alkylene glycols. The polyalkylene glycols are preferably polyalkylene glycols with two methyl or ethyl end caps.

[0064] The molecular weight M of suitable polyalkylene glycols, especially suitable polyethylene glycols, W may be at least 400 g / mol.

[0065] The molecular weight M of suitable polyalkylene glycols, especially suitable polyethylene glycols, W can be up to 5,000,000 g / mol, preferably up to 2,000,000 g / mol.

[0066] Examples of suitable acyclic ethers are, for example, diisopropyl ether, di-n-butyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, with 1,2-dimethoxyethane being preferred.

[0067] Examples of suitable cyclic ethers are tetrahydrofuran and 1,4-dioxane.

[0068] Examples of suitable acyclic acetals are, for example, dimethoxymethane, diethoxymethane, 1,1-dimethoxyethane and 1,1-diethoxyethane.

[0069] An example of a suitable cyclic acetal is 1,3-dioxane, and especially 1,3-dioxolane.

[0070] Examples of suitable acyclic organic carbonates are dimethyl carbonate, ethyl methyl carbonate and diethyl carbonate.

[0071] Examples of suitable cyclic organic carbonates are compounds of the general formulae (II) and (III) [ka] (In the formula, R 1 , R 2 and R 3 can be the same or different and are selected from hydrogen and C1-C4-alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, preferably R 2 and R 3 (Both cannot be tert-butyl).

[0072] In a particularly preferred embodiment, R 1 is methyl and R 2 and R 3 are each hydrogen or R 1 , R 2 and R 3 are hydrogen atoms.

[0073] Another preferred cyclic organic carbonate is vinylene carbonate of formula (IV).

[0074] [ka]

[0075] Preferably, the solvent or solvents are used in an anhydrous state, ie with a water content in the range of 1 ppm to 0.1% by weight, which can be determined, for example, by Karl Fischer titration.

[0076] The electrolyte (3) further comprises at least one electrolyte salt. Suitable electrolyte salts are, in particular, lithium salts. Examples of suitable lithium salts are LiPF, LiBF, LiClO, LiAsF, LiCF, SO, LiC(C n F 2n+1 SO2)3, lithium imide, e.g., LiN(C n F 2n+1 SO2)2 (wherein n is an integer ranging from 1 to 20), LiN(SO2F)2, Li2SiF6, LiSbF6, LiAlCl4, and compounds of the general formula (C n F 2n+1 SO2) t YLi salt wherein t=1 when Y is selected from oxygen and sulfur; when Y is selected from nitrogen and phosphorus, t=2; When Y is selected from carbon and silicon, t=3).

[0077] Preferred electrolyte salts are selected from LiC(CF3SO2)3, LiN(CF3SO2)2, LiPF6, LiBF4, LiClO4, with LiPF6 and LiN(CF3SO2)2 being particularly preferred.

[0078] In a preferred embodiment of the present invention, the electrolyte (3) contains at least one flame retardant. Useful flame retardants may be selected from trialkyl phosphates (wherein the alkyls are different or the same), triaryl phosphates, alkyl dialkyl phosphonates, and halogenated trialkyl phosphates. Preferred are tri-C1-C4-alkyl phosphates (wherein the C1-C4-alkyls are different or the same), tribenzyl phosphate, triphenyl phosphate, C1-C4-alkyl di-C1-C4-alkyl phosphonates, and fluorinated tri-C1-C4-alkyl phosphates.

[0079] In a preferred embodiment, the electrolyte (3) comprises at least one flame retardant selected from trimethyl phosphate, CH3-P(O)(OCH3)2, triphenyl phosphate, and tris-(2,2,2-trifluoroethyl)-phosphate.

[0080] The electrolyte (3) may contain 1 to 10 mass % of a flame retardant based on the total mass of the electrolyte.

[0081] In one embodiment of the present invention, the electrolyte (3) is solid at room temperature and contains sulfur and phosphorus, and is hereinafter also referred to as solid electrolyte (3).

[0082] In this context, the term "solid" refers to the state of matter at room temperature.

[0083] In one embodiment of the present invention, the solid electrolyte (3) has a lithium ion conductivity at 25° C. of 0.1 mS / cm or more, preferably in the range of 0.1 to 30 mS / cm, which can be measured, for example, by impedance spectroscopy.

[0084] In one embodiment of the present invention, the solid electrolyte (3) comprises Li3PS4, even more preferably orthorhombic β-Li3PS4.

[0085] In one embodiment of the present invention, the solid electrolyte (3) is Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2-P2S5-LiI, Li2S-P2S5-Z m S n (wherein m and n are positive numbers, and Z is selected from the group consisting of germanium, gallium, and zinc), Li2S-SiS2-Li3PO4, Li2S-SiS2-Li y PO z (wherein y and z are positive numbers), Li7P3S 11 , Li3PS4, Li 11 S2PS 12 , Li7P2S8I, and Li 7-r-2s PS 6-r-s X 1 r (In the formula, X 1 is chlorine, bromine, or iodine, and the variables are defined as follows: 0.8≦r≦1.7 0≦s≦(-0.25r)+0.5) is selected from the group consisting of:

[0086] A particularly preferred example of the solid electrolyte (3) is Li6PS5Cl, so that r=1.0 and s=0.

[0087] In one embodiment of the present invention, the solid electrolyte (3) is doped with at least one of Si, Sb, and Sn. Preferably, Si is provided as an element. Preferably, Sb and Sn are provided as sulfides.

[0088] In an embodiment of the present invention, the battery according to the present invention includes one or more separators (4) by which the electrodes are mechanically separated. Preferred separators (4) are polymer films, particularly porous polymer films, that are unreactive with metallic lithium. Particularly preferred materials for separators (4) are polyolefins, particularly film-forming porous polyethylene and film-forming porous polypropylene.

[0089] The separator (4) made of polyolefin, particularly polyethylene or polypropylene, can have a porosity in the range of 35 to 50%. The preferred pore size is, for example, in the range of 30 to 500 nm.

[0090] In another embodiment of the present invention, the separator (4) can be selected from PET nonwoven fabrics filled with inorganic particles. Such separators can have a porosity in the range of 40 to 55%. Suitable pore sizes are, for example, in the range of 80 to 750 nm.

[0091] The battery according to the invention may further comprise a housing which may have any shape, for example a cube or a cylindrical disk. In one variant, a metal foil configured as a pouch is used as the housing.

[0092] The battery according to the invention exhibits very good discharge and cycling behavior, especially with regard to capacity loss, especially at high temperatures (above 45° C., eg even up to 60° C.).

[0093] The battery according to the present invention may comprise two or more electrochemical cells which are combined with one another, for example, connected in series or in parallel. A series connection is preferred. In the battery according to the present invention, at least one electrochemical cell contains at least one electrode according to the present invention. Preferably, in the electrochemical cell according to the present invention, the majority of the electrochemical cells contain the electrode according to the present invention. Even more preferably, in the battery according to the present invention, all electrochemical cells contain the electrode according to the present invention.

[0094] The present invention further provides a method for using the battery according to the present invention in a device, in particular a mobile device. Examples of mobile devices are vehicles, such as automobiles, bicycles, aircraft, or water vehicles, such as boats or ships. Other examples of mobile devices are manually operated devices, such as computers, in particular laptops, telephones, or powered hand tools, for example in the construction sector, in particular drills, battery-powered screwdrivers, or battery-powered staplers.

[0095] The present invention is further illustrated by examples. [Example]

[0096] NMP: N-methylpyrrolidone The crack level was determined as follows: SEM images of randomly selected particles were analyzed using an edge detection algorithm called "canny," which calculates the gradient of image intensity. This algorithm applies a dual threshold to determine potential edges and tracks them using hysteresis to detect the final edge of the object. For example, as shown in Figure 1b, cracks within secondary particles and the particle outline were detected as edges. The particle area was eroded to remove the particle outline, and the remaining edge was defined as a crack. The crack pixels were normalized by the particle area and are shaded gray in Figure 1c. The detected crack pixels are normalized by the particle and are shown in the gray shaded area in Figure 1c.

[0097] Unless otherwise stated, percentages are by weight.

[0098] (B.1): Synthetic graphite, platelet-like, particle size 6 μm.

[0099] I. Production of the electrode active material of the present invention I.1 Synthesis of precursor TM-OH.1 Deionized water and an aqueous solution of 49 g of ammonium sulfate per kg of water were placed in a stirred tank reactor. The solution was thermostated at 55° C. and the pH was adjusted to 12 by adding aqueous sodium hydroxide.

[0100] The coprecipitation reaction was initiated by simultaneously feeding aqueous transition metal sulfate solutions and aqueous sodium hydroxide solutions at a flow rate ratio of 1.8, with a total flow rate and a residence time of 8 hours. The transition metal solution contained Ni, Co, and Mn in a molar ratio of 8.3:1.2:0.5 and a total transition metal concentration of 1.65 mol / kg. The aqueous sodium hydroxide solution was a 25 wt% sodium hydroxide solution and a 25 wt% ammonia solution in a mass ratio of 6. The pH value was maintained at 12 by separately feeding the aqueous sodium hydroxide solution. Starting from the start of all feeds, the mother liquor was continuously removed. After 33 hours, all feed flows were stopped. The resulting suspension was filtered, washed with distilled water, dried in air at 120°C, and sieved to obtain the mixed transition metal (TM) hydroxide precursor TM-OH.1. Average particle size (D50): 10.6 μm.

[0101] I.2 Conversion of TM-OH.1 into cathode active material I.2.1 Preparation of Base Cathode Active Material, B-CAM.1, Step (a.1) B-CAM.1 (Base): The mixed transition metal hydroxide precursor TM-OH.1 was mixed with LiOH monohydrate, TiO2, and ZrO2 in a Li / (TM) molar ratio of 1.03. The amounts of Ti and Zr were adjusted to obtain 0.17 mol% Ti and 0.17 mol% Zr relative to the total amount of TM (TM = Ni + Co + Mn + Ti + Zr). The resulting mixture was heated to 780°C and held in a forced flow of a mixture of 60% oxygen and 40% nitrogen (volume ratio) for 10 hours. After cooling to room temperature, the resulting powder was deagglomerated and sieved through a 32 μm mesh. The base cathode active material, B-CAM 1, was obtained.

[0102] The D50 determined using laser diffraction techniques on a Mastersize 3000 machine from Malvern Instruments was 10.6 μm. The residual moisture determined at 250 °C was 300 ppm. Specific surface area (BET): 0.17 m 2 / g.

[0103] I.2.2 Mixing with carbon (B), step (b.1) B-CAM.1 and (B.1) were mixed in a mass ratio of 100:3 in a bottle of a roller mixer at room temperature for 1 hour to obtain a mixture.

[0104] I.2.3 Exposure to Pressure, Step (c.1) A 5 g quantity of the mixture obtained from step (b.1) was placed in a pellet press with an inner diameter of 16.07 mm and pressed at 150 MPa for 10 seconds. The pressure was then released, and the tablet formed under pressure was removed from the tablet press, gently de-lumped, and sieved through a 32 μm vibrating sieve. A free-flowing powder of CAM.1 was obtained. A crack level of 5.9 was determined by image analysis.

[0105] I.2.4 Exposure to Pressure, Step (c.2) A 5 g quantity of the mixture obtained from step (b.1) was placed in a pellet press with an inner diameter of 16.07 mm and pressed at 300 MPa for 10 seconds. The pressure was then released, and the tablet formed under pressure was removed from the tablet press, gently de-lumped, and sieved through a 32 μm vibrating sieve. A free-flowing powder of CAM.2 was obtained. A crack level of 21.1 was determined by image analysis.

[0106] II. Electrode Fabrication II.1 Cathode preparation, steps (d) and (e) Steps (d.1), (d.2) and C-(d.3): PVDF binder (Solef® 5130) was dissolved in NMP (Merck) to prepare an 8.0 wt% solution. For electrode preparation, the binder solution (4 wt%) and carbon black (Li250, 3.5 wt%) were suspended in NMP. After mixing using a planetary centrifugal mixer (ARE-250, Thinky Corp.; Japan), either CAM.1 (step (d.1)) or CAM.2 (step (d.2)) of the present invention or the base cathode active material B-CAM.1 (step C-(d.3)) was added, and the suspension was mixed again to obtain a lump-free slurry. The solids content of the slurry was adjusted to 65%.

[0107] Step (e.1): The slurry from step (d.1) was coated onto an Al foil using a KTF-S roll-to-roll coater (Mathis AG).

[0108] Step (e.2): The slurry from step (d.2) was coated onto an Al foil using a KTF-S roll-to-roll coater (Mathis AG).

[0109] Step C-(e.3): The slurry from step C-(d.1) was coated onto Al foil using a KTF-S roll-to-roll coater (Mathis AG).

[0110] Electrode coating is 15mg / cm 2 Before assembling the battery, all electrodes were dried at 120°C for 7 hours.

[0111] II.2 Electrolyte Production A base electrolyte composition (EL Base 1) containing 12.7 wt% LiPF6, 26.2 wt% ethylene carbonate (EC), and 61.1 wt% ethyl methyl carbonate (EMC) was prepared. 2 wt% vinylene carbonate (VC) was added to this electrolyte formulation (EL Base 2).

[0112] II.3 Test cell construction Coin-shaped half-cells (20 mm diameter, 3.2 mm thickness) containing the cathode prepared as described in Section III.1.1 and lithium metal as the working and counter electrodes were assembled and sealed in an Ar-filled glove box. The cathode, anode, and separator were stacked in the order cathode / separator / Li foil to fabricate half-coin cells. Then, 0.15 mL of the EL base 1 described above (III.2) was introduced into the coin cells.

[0113] III. Evaluation of the performance of coin half-cells The cell performance was evaluated using the fabricated coin-type batteries. Regarding the battery performance, the initial capacity and reaction resistance of the cells were measured. The initial performance and rate performance were measured as follows: The coin-type half-cells described in II.3.1 were tested at 25°C in the voltage range of 4.3 V to 3.0 V. For the initial cycle, initial lithiation was performed in CC-CV mode. That is, a constant current (CC) of 0.1 C was applied until the voltage reached 0.01 C. Reductive lithiation was performed at a constant current of 0.1 C until the voltage reached 3.0 V. After the formation cycle, the rate characteristics were measured at 3 C discharge. The relative rate performance [%] was based on the discharge capacity at 0.1 C. The results are summarized in Table 1.

[0114] Cycling performance was evaluated as follows: After initial performance evaluation, coin cells were cycled at 25°C with 0.5C CC-CV charging and 1C CC discharging. Before and after cycling, direct current internal resistance ("DCIR") was measured by applying a 0.5C discharge for 30 seconds at 50% state of charge. The cycle retention and DCIR increase rates are based on the values ​​before cycling taken as 100%. The results are summarized in Tables 1 and 2.

[0115] [Table 1]

[0116] [Table 2]

Claims

1. The following steps: (a) Formula Li １＋ｘ TM １－ｘ O ２ providing a lithiated transition metal oxide according to the formula: wherein x ranges from 0 to 0.1, and TM contains nickel and at least one of Co, Mn, and Al; (b) combining the lithiated transition metal oxide from step (a) with a conductive form of carbon; (c) exposing the mixture obtained in step (b) to a pressure in the range of 100 to 500 MPa for a period of 1 second to 1 minute, thereby cracking at least a portion of the particles of the electrode active material; (d) mixing the mixture from step (c) with a binder polymer, optionally with additional conductive forms of carbon, and a solvent; (e) applying the mixture from step (d) to a metal foil; A method for manufacturing an electrode, comprising:

2. TM is a compound represented by the general formula (I): (Ni a Co b Mr c ) 1-d M 1 d (I) (wherein a is in the range of 0.6 to 1.0, b is in the range of 0 to 0.2; c is in the range of 0 to 0.2; d is in the range of 0 to 0.1; M １ is selected from Al, Ti, Zr, W, Nb, Ta, Mo, Mg, and combinations of at least two thereof; a+b+c=1, at least one of b, c and d is greater than 0); The method of claim 1, wherein the combination of elements is

3. 3. The method of claim 1 or 2, wherein in step (b), the conductive form of carbon is graphite.

4. 4. The method of claim 1, wherein step (c) is carried out in an isostatic press.

5. 5. The method according to any one of claims 1 to 4, wherein the crack level of the particles after step (c) is in the range of 5 to 30, said crack level being determined with the help of SEM image(s) analysed by an edge detection algorithm which calculates the gradient of the image intensity and thus detects the cracks.

6. 6. The method of any one of claims 1 to 5, wherein the mass ratio of the electrode active material to graphite provided in step (a) is in the range of 100:1 to 20:

1.

7. General formula Li １＋ｘ TM １－ｘ O ２ wherein x is in the range of 0 to 0.1 and TM contains nickel and at least one of Co, Mn and Al, wherein at least 25% of all particles have a crack level in the range of 5 to 30, such cracks containing carbon in a conductive form, said crack level being determined with the aid of SEM image(s) analyzed by an edge detection algorithm which calculates the gradient of the image intensity and thus detects the cracks.

8. TM is a compound represented by the general formula (I): (Ni a Co b Mr c ) 1-d M 1 d (I) (wherein a is in the range of 0.6 to 1.0, b is in the range of 0 to 0.2; c is in the range of 0 to 0.2; d is in the range of 0 to 0.1; M １ is selected from Al, Ti, Zr, W, Nb, Ta, Mo, Mg, and combinations of at least two thereof; a+b+c=1, at least one of b, c and d is greater than 0); The particulate electrode active material according to claim 7, wherein the combination of elements is

9. The particulate electrode active material according to claim 7 or 8, wherein the cracks are substantially free of binder polymer.

10. 10. A particulate electrode active material according to any one of claims 7 to 9, wherein at least 60% of the particles of the electrode active material exhibit cracks.

11. The variables in TM are selected as follows: a is in the range of 0.75 to 0.95; b is in the range of 0.025 to 0.125; c is in the range of 0.025 to 0.125; d is in the range of 0 to 0.1; M １ The particulate electrode active material according to any one of claims 7 to 10, wherein is selected from Al, Ti and Zr.

12. (A) at least one particulate electrode active material according to any one of claims 7 to 11; (B) at least one binder, and optionally (C) Further Conductive Forms of Carbon a cathode.

13. (1) The cathode according to claim 12, (2) an anode, and (3) Electrolyte an electrochemical cell comprising:

14. 14. Electrochemical cell according to claim 13, wherein the electrolyte (3) is solid at room temperature and is selected from electrolytes containing sulfur and phosphorus.

15. The electrolyte (3) is Li ２ S-P ２ S ５ , Li ２ S-P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Li ２ O, Li ２ S-P ２ S ５ -Li ２ O-LiI, Li ２ S-SiS ２ -P ２ S ５ - LiI, Li ２ S-P ２ S ５ -Z ｍ S ｎ wherein m and n are positive numbers, and Z is selected from the group consisting of germanium, gallium, and zinc; Li ２ S-SiS ２ -Li ３ P.O. ４ , Li ２ S-SiS ２ -Li ｙ P.O. ｚ (wherein y and z are positive numbers), Li ７ P ３ S １１ , Li ３ P.S. ４ , Li １１ S ２ P.S. １２ , Li ７ P ２ S ８ I, and Li ７－ｒ－２ｓ P.S. ６－ｒ－ｓ X １ ｒ (In the formula, X １ is chlorine, bromine, or iodine, and the variables are defined as follows: 0.8≦r≦1.7 0≦s≦(-0.25r)+0.5) 15. The electrochemical cell of claim 14, selected from the group consisting of:

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