Formulation and design of an anode coating based on a graphite-silicon active material mixture for a lithium-ion battery

Abstract

The present invention relates to a coating for a negative electrode having said coating, to a method for the production of said negative electrode, to electrical cells having said negative electrode, to lithium-ion batteries, and to devices having said lithium-ion batteries.

Description

[0001] Description

[0002] Formulation & design of an anode coating based on a graphite-silicon active material mixture for a lithium-ion battery

[0003] The present invention relates to a coating for a negative electrode, a negative electrode having this coating, methods for its production, and electrical cells, lithium-ion batteries, and devices having this negative electrode.

[0004] Electrical energy storage systems are considered a key technology, particularly in electromobility. Current developments aim to optimize these systems with regard to aspects such as manufacturing costs, weight, energy density, lifespan, and charging speed.

[0005] The demands placed on such electrical energy storage devices are constantly increasing, especially the demands on the energy density and charging times of the electrical energy storage device.

[0006] An electrical energy storage device, hereinafter also referred to as a battery, has at least one positive electrode, or cathode, and at least one negative electrode, or anode. The electrodes typically have a coating containing an active material. When the electrical energy storage device is charged, the active material of the positive electrode releases electrons, and the active material of the negative electrode accepts electrons. When the electrical energy storage device is discharged, the active material of the negative electrode releases electrons, and the active material of the positive electrode accepts electrons. The capacitance of the active materials corresponds to the amount of electrons that the active material can release or accept. Often, in addition to the active material, a binder, particularly a polymer, is also present in the active material.The binder, especially the polymeric one, increases the internal cohesion of the active material.

[0007] Known devices that attempt to meet these requirements include those with coatings for a negative electrode containing graphite and silicon-based active material. Disadvantages of such coatings include a short lifespan, significant volume changes in the active material and the cell containing it, strong gas evolution in liquid, especially aqueous, media, and the potential for the silicon-based material to break down.

[0008] Attempts to overcome the known disadvantages have involved the use of silicon oxide as well as various types of silicon-carbon mixtures or silicon nanoparticles, but the disadvantages persist.

[0009] Patent application US 2019 / 0237753 A1 discloses an anode active material for a lithium-ion battery comprising silicon monoxide particles, graphite particles, a carbon cover layer, wherein the graphite particles and the silicon monoxide particles are mixed together to form spherical silicon monoxide-graphite composite particles.

[0010] The patent application WO 2024 / 036849 discloses an electrode with a ceramic coating comprising a ceramic powder and a binder, wherein the electrode surface has a roughness of 0.4 pm to 1.6 pm.

[0011] The patent application EP 4 220 752 A2 discloses an anode for a secondary battery comprising an anode current collector, a first anode active material layer and a second anode active material layer, wherein the first and second anode active material layers comprise graphite-based anode active material, silicon-based anode active material and carbon nanotubes, wherein a Raman value of the carbon nanotubes in the second anode active material is smaller than a Raman value of the carbon nanotubes in the first anode active material.

[0012] The patent application WO 2023 / 099002 A1 discloses a process for utilizing silicon-containing materials by removing excess silicon from particle surfaces, as well as the use of the silicon-containing materials thus obtained as active materials for anodes of lithium-ion batteries.

[0013] Patent application US 2020 / 0075954 A1 discloses a material comprising a variety of composite particles, wherein the composite particles contain: (a) a porous carbon skeleton comprising micropores and mesopores and exhibiting the following properties: (i) a total pore volume of more than 0.6 cm³ 3 (g) (ii) a volume fraction of micropores in the range of 20-50% and a volume fraction of mesopores in the range of 50-80%; (iii) a proportion of the pore volume of pores with a size of not more than 10 nm that constitutes at least 75% of the total pore volume; and (iv) a Dv50 value in the range of 5 nm to 20 pm; and (b) nanostructured silicon embedded in the pores of the porous carbon framework, wherein the weight fraction of the nanostructured silicon in the porous carbon framework is in the range of 10% to 80%.

[0014] The present invention is based on the objective of improving a coating for a negative electrode in such a way that it has a long, and in particular longer, lifetime, causes a small, and in particular smaller, volume change of the active material and the cell to which the coating may belong, and causes low, and in particular lower, gas evolution in liquid, and in particular aqueous, media, especially compared to known coatings. In particular, the present invention is based on the objective of increasing the energy density and fast-charging capability and shortening the charging times of a cell comprising a coating for a negative electrode.

[0015] The problem underlying the invention is solved by a coating for a negative electrode with the features of claim 1. The interaction of the materials, and in particular their composition, of the coating according to the invention produces synergistic effects that lead to increased energy density, a longer lifetime, and improved fast-charging capability compared to known coatings, especially when used with a negative electrode coated therewith. Advantageously, such an interaction, particularly due to the composition, results in smaller volume changes of the active material and causes less gas evolution from the coating according to the invention in a possible reaction with water than known coatings, especially when used with a negative electrode coated therewith.Without being bound to theory, a smaller volume expansion leads to fewer partial fractures and fewer fractures in the surface of the coating according to the invention, particularly in the negative electrode comprising the coating according to the invention. This results in less solid electrolyte interphase (SEI) formation during cycling, leading to less lithium loss and consequently a longer service life of the coating according to the invention, especially of the negative electrode comprising the coating according to the invention. Preferably, this also leads to less gas evolution.

[0016] According to the invention, the coating comprises an active material, a silicon-carbon material (Si / C), in particular a gas-treated one, and graphite, wherein the carbon is a porous carbon, particularly in the form of porous carbon particles, and wherein the surface of the graphite has been treated with oxygen, nitrogen, methane, ethane, propane, butane, ethene, propene, and / or butene prior to use. Preferably, the porous carbon is in the form of porous carbon particles. Preferably, the porous carbon, in particular the porous carbon particles, has pores. Preferably, silicon, in particular pure silicon, is present in the porous carbon, in particular in the pores of the porous carbon. Preferably, the silicon, in particular pure silicon, is deposited in the porous carbon, in particular in the pores of the porous carbon. Preferably, the silicon, in particular pure silicon, is deposited from the gas phase.Advantageously, this ensures the electronic conductivity in the porous carbon, especially in the respective porous carbon particles, and the stability of the porous carbon, especially the respective porous carbon particles, in the normal state, particularly in comparison to known coatings.

[0017] The silicon-carbon material of the active material of the coating according to the invention, particularly gas-treated, ensures long-term stability of the active material and compensation for its volume expansion during use, especially compared to known coatings. Advantageously, the silicon-carbon material also results in a reduced, and in particular no, reaction between the electrolyte and the silicon due to the encapsulation, i.e., the presence, of the silicon within the porous carbon, particularly within the pores of the porous carbon, especially the porous carbon particles, of the active material of the coating according to the invention.Preferably, the gas treatment of the silicon-carbon material before use in a coating according to the invention advantageously prevents reactions during liquid, in particular aqueous, processing during the use of the coating according to the invention and thus prevents gas evolution in liquid, in particular aqueous, media.

[0018] According to the invention, the surface of the graphite was treated with oxygen, nitrogen, methane, ethane, propane, butane, ethene, propene and / or butene before use. This ensures the rapid charging capability of the coating.

[0019] According to the invention, the coating further comprises a binder with polar functional groups. Advantageously, the polar functional groups of the binder achieve a strong bond to the active material, particularly via hydrogen bonds and / or van der Waals interactions, especially compared to binders without polar functional groups, such as a styrene-butadiene rubber binder. This compensates for the volume expansion of the active material, particularly compared to known coatings, especially those comprising a styrene-butadiene rubber binder and carboxymethylcellulose and a silicon-containing active material. In these known coatings, rapid degradation occurs due to the volume expansion of the silicon in the active material during electrical charging and discharging, causing the coating structure to break down.Without being bound to theory, such a disadvantage is reduced, and in particular avoided, by the binder having polar functional groups in combination with the other materials, especially the active material, and particularly due to the composition of the materials in the coating according to the invention. Thus, the strong bond between the binder and the active material, due to the polar functional groups, compensates for the volume change of the active material during charging and discharging in such a way that it does not lead to a break in the bonds within the coating and consequently to a disruption of the coating's structure, especially at the surface of the coating.This preferably results in less solid electrolyte interphase (SEI) formation during cycling, leading to less lithium loss and consequently a longer service life of the coating according to the invention, in particular of the negative electrode comprising the coating according to the invention. This also leads to less gas evolution.

[0020] According to the invention, the coating further comprises carbon nanotubes containing an additive. Advantageously, the carbon nanotubes form a conductive network within the coating. This advantageously increases the stability of the coating. The conductive network formed by the carbon nanotubes allows the binder to penetrate the network and, in combination with the active material, particularly due to the composition of the materials, provides a fast-charging coating with high energy density and good cycle stability, especially compared to known coatings.

[0021] In a preferred embodiment, the coating comprises 90 to 98% by mass, in particular 92 to 96% by mass, in particular 90% by mass, in particular 94% by mass, in particular 98% by mass, of the anode active material, based on the total mass of the coating. At such a mass fraction, particularly in combination with the other materials, especially the mass fractions of the other materials in the coating, sufficient long-term stability of the active material and compensation for the volume expansion of the active material during use are ensured.In a preferred embodiment, the anode active material comprises 5 to 50 wt%, in particular 10 to 40 wt%, in particular 15 to 30 wt%, in particular 16 wt%, in particular 19 wt%, in particular 23 wt%, of the silicon-carbon material (Si / C) and 50 to 95 wt%, in particular 60 to 90 wt%, in particular 70 to 85 wt%, in particular 84 wt%, in particular 81 wt% of graphite, in particular 77 wt%, each based on the total mass of the active material. With such mass fractions, especially in combination with the other materials, in particular the mass fractions of the other materials of the coating, sufficient long-term stability of the active material and compensation for the volume expansion of the active material during use are ensured.Furthermore, this results in a reduced, and in particular no, reaction between an electrolyte and the silicon when used, especially compared to known coatings having an active material having a silicon-carbon material.

[0022] In a preferred embodiment, the silicon-carbon material is a gas-treated silicon-carbon material. In a preferred embodiment, the graphite is naturally occurring or synthetically produced graphite. Advantageously, this results in fewer, and in particular no, reactions during liquid, especially aqueous, processing when using the coating according to the invention, and thus no gas evolution occurs in liquid, especially aqueous, media.

[0023] In a preferred embodiment, the coating has a mass fraction of binder of 1.1 to 7.0 wt%, in particular 2.0 to 6.0 wt%, in particular 2.0 to 4.5 wt%, in particular 3.2 wt%, in particular 4.5 wt%, in particular 5.9 wt%, based on the total mass of the coating. At such a mass fraction, especially in combination with the other materials, particularly the mass fractions of the other materials in the coating, any volume expansion of the active material is compensated.

[0024] In a preferred embodiment, the binder comprises 1.0 to 5.0 wt%, in particular 2.0 to 4.0 wt%, in particular 2.0 to 3.0 wt%, in particular 2.5 wt%, in particular 3.0 wt%, in particular 3.8 wt%, of a styrene-butadiene polymer, in particular comprising, in particular substituted with, the polar functional groups, in particular acrylic acid groups, and 0.1 to 2.0 wt%, in particular 0.2 to 1.8 wt%, in particular 0.5 to 1.8 wt%, in particular 0.5 to 1.6 wt%, in particular 0.6 wt%, in particular 1.6 wt%, carboxymethylcellulose, in each case based on the total mass of the coating, in particular consisting thereof. Such mass fractions, especially in combination with the other materials, particularly the mass fractions of the other materials in the coating, ensure that any volume expansion of the active material is compensated.

[0025] In a preferred embodiment, the binder comprises at least one material selected from the group consisting of polyacrylic acid, lithium polyacrylic acid, alginate, carboxymethylcellulose, styrene-butadiene rubber, and combinations thereof. In a preferred embodiment, the binder comprises a styrene-butadiene polymer, in particular comprising the polar functional groups, in particular acrylic acid groups, carboxymethylcellulose, and polyacrylic acid. In a preferred embodiment, the styrene-butadiene polymer comprises the polar functional groups. In a preferred embodiment, the polar functional groups are selected from the group consisting of alcohol groups, ester groups, keto groups, nitrile groups, carboxylic acid groups, in particular acrylic acid groups, and combinations thereof.These materials, which possess the functional groups, ensure a strong bond between the active material and the binder, preventing a break in the bonds within the coating and thus a breakdown of the coating's structure.

[0026] In a preferred embodiment, the active material of the coating comprises 30 to 50 wt% of the silicon-carbon material (Si / C) based on the total mass of the coating, and the binder is a styrene-butadiene polymer, in particular comprising the polar functional groups, especially acrylic acid groups, carboxymethylcellulose, and polyacrylic acid. Advantageously, this strengthens the bond between the binder and the active material, in particular the silicon-carbon material, and increases the stability.

[0027] Preferably, the styrene-butadiene polymer is a styrene-butadiene polymer substituted with acrylic acid as a polar functional group, in particular styrene-butadiene rubber. Preferably, the styrene-butadiene polymer substituted with acrylic acid is a styrene-butadiene-acrylic acid copolymer. Preferably, the acrylic acid as the polar functional group of the styrene-butadiene polymer results in a stronger bond, in particular via hydrogen bonds and / or van der Waals interactions, to the active material, in particular the silicon-carbon material, especially compared to styrene-butadiene rubber, so that a change in volume of the active material does not lead to a break in the bond in the coating according to the invention, in particular as with the use of styrene-butadiene rubber, which leads to severe aging during the electrical charging and discharging of the active material.A styrene-butadiene polymer, particularly styrene-butadiene rubber, is preferably used as the molecule to be substituted for the acrylic acid substitution. This is especially true because styrene-butadiene polymers, particularly styrene-butadiene rubber, exhibit sufficient flexibility, unlike pure polyacrylic acid, which is too rigid. This allows the acrylic acid-substituted styrene-butadiene polymer to be processed easily and exhibits good bonding to the active material.

[0028] In a preferred embodiment, the coating comprises 0.11 to 5.3 wt%, in particular 0.5 to 3.0 wt%, in particular 1.0 to 2.0 wt%, in particular 1.25 wt%, in particular 1.5 wt%, in particular 1.9 wt%, of the additive, based on the total mass of the coating, and in particular consists thereof. In a preferred embodiment, the additive comprises 0.1 to 3.0 wt%, in particular 0.1 to 2.0 wt%, in particular 0.7 wt%, in particular 1.4 wt%, conductive carbon black and 0.01 to 0.30 wt%, in particular 0.05 to 0.20 wt%, in particular 0.05 wt%, in particular 0.09 wt%, in particular 0.10 wt%, in particular single-walled carbon nanotubes, each based on the total mass of the coating. In a preferred embodiment, the additive comprises graphene.Such mass fractions, particularly in combination with the other materials, especially the mass fractions of the other materials in the coating, advantageously increase the stability of the coating. This preferably provides a fast-charging coating with high energy density and good charge and discharge cycle stability, especially compared to known coatings.

[0029] In a preferred embodiment, the carbon nanotubes are single-walled carbon nanotubes. Advantageously, the use of single-walled carbon nanotubes forms a network that contributes to stabilizing the coating and also increases the conductivity in the coating.

[0030] In a preferred embodiment, the silicon is homogeneously distributed in 0.1 to 99.0%, particularly 10 to 99%, particularly 50 to 95%, particularly 70 to 90%, particularly 40 to 70%, particularly 50% of the pores of the carbon, particularly the carbon particles, based on the average number of pores of the porous carbon, particularly the carbon particles. In a preferred embodiment, the pores in which no silicon is present form cavities. Advantageously, this compensates for the expansion of the silicon within the particle. Preferably, the cavities allow for volume expansion within a carbon particle during the charging of a lithium-ion battery comprising the coating according to the invention.It is ensured that the coating retains its stability during loading and unloading and the associated volume expansion.

[0031] In a preferred embodiment, the surface of the porous carbon, in particular the carbon particles, of the silicon-carbon material is free of pure silicon. In a preferred embodiment, no pure silicon is present on the surface of the porous carbon, in particular the porous carbon particles. This advantageously reduces, and in particular prevents, parasitic reactions with an electrolyte, such as reductive decomposition of the electrolyte.

[0032] In a preferred embodiment, the surface of the silicon-carbon material was treated with hydrocarbons, in particular with methane, ethane, propane, butane, ethene, propene and / or butene, prior to use. Advantageously, this reduces, and in particular prevents, gas formation in an aqueous medium, especially during aqueous processing.

[0033] In a preferred embodiment, the silicon-carbon material comprises 1 to 40 vol.%, in particular 33 vol.%, of porous carbon and 1 to 40 vol.%, in particular 33 vol.%, of silicon, each based on the total volume of the silicon-carbon material. In a preferred embodiment, the silicon-carbon material comprises 1 to 40 vol.%, in particular 33 vol.%, of porous carbon, 1 to 40 vol.%, in particular 33 vol.%, of silicon, and 1 to 40 vol.%, in particular 33 vol.%, of cavities, each based on the total volume of the silicon-carbon material. Advantageously, this maintains the stability of the material during electrical charging and discharging.

[0034] In a preferred embodiment, the graphite has a mean particle size dso of 5 to 15 pm, in particular 7 to 13 pm, in particular 9 to 12 pm, and in particular 12 pm. Preferably, due to the mean particle size dsovon of 5 to 15 pm, in particular 7 to 13 pm, in particular 9 to 12 pm, and in particular 12 pm, lithium dendrite formation does not occur, especially at high charging currents.

[0035] In a preferred embodiment, the coating according to the invention for a negative electrode comprises a) 90 to 98 wt% of an active material, based on the total mass of the coating, in particular comprising a1) 5 to 50 wt%, based on the total mass of the active material, of a gas-treated silicon-carbon material (Si / C), wherein the carbon is a porous carbon, wherein the surface of the porous carbon is free of pure silicon and the silicon-carbon material comprises 1 to 40 vol%, in particular 33 vol%, of the porous carbon and 1 to 40 vol%, in particular 33 vol%, of the active material.-% of silicon, based on the total volume of the silicon-carbon material, and the remainder is void, a2) 50 to 95 wt%, based on the total mass of the active material, naturally occurring or artificially produced graphite, b) 1.1 to 7.0 wt%, based on the total mass of the coating, comprising a binder having polar functional groups, wherein the binder comprising 1.0 to 5.0 wt%, based on the total mass of the coating, a styrene-butadiene polymer, in particular styrene-butadiene rubber, in particular substituted with the having polar functional groups and 0.1 to 3.0 wt%, based on the total mass of the coating, carboxymethylcellulose, in particular consisting thereof, wherein the functional groups are acrylic acid groups, c) 0.11 to 5.3 wt%, based on the total mass of the coating, comprising an additive, in particular consisting of,

[0036] 0.01 to 0.30 wt%, based on the total mass of the coating, carbon nanotubes, wherein the carbon nanotubes are single-walled carbon nanotubes, and

[0037] 0.1 to 5.0 mass-%, based on the total mass of the conductive carbon black coating, in particular consists of this.

[0038] Another aspect of the present invention is a method for producing a negative electrode, wherein the method comprises the following process steps: x) providing a coating according to one of claims 1 to 6 and a substrate, y) coating the substrate with the coating and z) obtaining a negative electrode.

[0039] Advantageously, this results in a negative electrode in which, through the interaction of the materials, and especially their composition, synergistic effects are created, leading to an increased energy density, a longer lifespan and an increased fast-charging capability compared to known negative electrodes.

[0040] Another aspect of the present invention is a negative electrode comprising a coating according to the invention or a negative electrode producible according to a method according to the invention. Due to the interaction of the materials, and in particular their mass fraction composition, of the coating according to the invention, the negative electrode according to the invention advantageously exhibits high stability and energy density as well as good fast-charging capability, in particular higher stability and energy density as well as better fast-charging capability than known negative electrodes. The materials, in particular their mass fraction composition, of the coating according to the invention ensure an optimal interaction of the materials used.In this way, synergistic effects are achieved by combining the materials used in the coating according to the invention, leading to a high-performance negative electrode.

[0041] In a preferred embodiment, the negative electrode has a loading of 150 to 200 g / m². 2 , especially 160 to 190 g / m² 2 , especially 170 to 180 g / m² 2 , in particular 172 g / m² 2 , in particular 176 g / m² 2 , in particular 178 g / m² 2 , the coating according to the invention, in particular double-sided. Advantageously, such a charging leads to a high energy density and good fast-charging capability.

[0042] In a preferred embodiment, the negative electrode has a density of 1.00 to 1.70 g / cm³. 3 , in particular 1.45 to 1.70 g / cm³ 3 , especially 1.50 to 1.60 g / cm³ 3 , in particular 1.54 g / cm³ 3, in particular 1.57 g / cm³ 3 , in particular 1.59 g / cm³ 3 Advantageously, such a density leads to a high energy density and good fast-charging capability.

[0043] In a preferred embodiment, the negative electrode has a capacity of 2.50 to 7.00 mAh / cm². 2 , especially 3.50 to 5.00 mAh / cm² 2 , especially 4.00 to 5.00 mAh / cm² 2 , in particular 4.20 mAh / cm² 2 , in particular 4.55 mAh / cm² 2 , in particular 4.75 mAh / cm² 2Advantageously, such a capacity leads to a high energy density and good fast-charging capability. In a preferred embodiment, the negative electrode has a coating thickness of 10 to 90 pm, in particular 20 to 89 pm, in particular 40 to 60 pm, in particular 48 pm, in particular 52 pm, in particular 56 pm. Advantageously, such a coating thickness leads to a high energy density and good fast-charging capability.

[0044] In a preferred embodiment, the coating of the negative electrode has a porosity of 10 to 50%, particularly 10 to 45%, particularly 15 to 35%, particularly 22%, particularly 25%, based on the maximum possible porosity, which is theoretically determined in particular from the loading, density, and crystal density of the materials used. Such a porosity results in a stable negative electrode.

[0045] In a preferred embodiment, the substrate of the negative electrode is a copper foil, an aluminum foil, or a polymer foil coated with copper or aluminum. In combination with the coating, this results in a high energy density and good fast-charging capability of the negative electrode.

[0046] Another aspect of the present invention is an electric cell comprising a negative electrode according to the invention, a positive electrode, an electrolyte and a separator.

[0047] In a preferred embodiment, the positive electrode of the electrical cell according to the invention comprises an active material, in particular comprising, in particular consisting of, lithium nickel manganese cobalt oxide (NMC), a binder, in particular comprising, in particular consisting of, polyvinylidene fluoride (PVDF), at least one additive, in particular comprising, in particular consisting of, multi-walled carbon nanotubes, also referred to as multi-walled carbon nanotubes (MWCNTs), and conductive carbon black, and a substrate, in particular an aluminum foil.In a preferred embodiment, the electrolyte consists of a mixture of, in particular at least two, carbonate solvents selected from the group consisting of ethyl methyl carbonate (EMC), diethyl carbonate (DEC), propylene carbonate (PC), ethylene carbonate (EC), lithium hexafluorophosphate (LiPF6), and optionally at least one additive selected from the group consisting of fluoroethylene carbonate (FEC), lithium bisfluorosulfonimide (LiFSI), vinylene carbonate, lithium difluorophosphate (UPO2F2), propanesultone (PS), ethylene sulfate (DTD), lithium tetrafluoroborate (LiBF4), and propensultone (PES). Preferably, the mixture of carbonate solvents of the electrolyte comprises 0 to 20 wt% EC, 25 to 70 wt% EMC, 5 to 20 wt% DEC, and optionally 0 to 5 wt% PC, each based on the total mass of the mixture of carbonate solvents. Preferably, the electrolyte has a concentration of 0.8 to 1.2 M LiPFβ.Preferably, the electrolyte contains 0.0 to 4.0 wt% LiFSI, 0.0 to 1.5 wt% VC, 0.5 to 8.0 wt% FEC, 0.0 to 2.0 wt% UPO2F2, 0.5 to 2.0 wt% DTD, and 0.0 to 0.5 wt% PS, and optionally 0.0 to 0.5 wt% PES and / or 0.0 to 1.0 wt% UBF4, each based on the total mass of the electrolyte. Such an electrolyte composition ensures stable electron transfer and increases the lifespan of the electric cell.

[0048] In a preferred embodiment, the separator comprises a ceramic-coated polymer with or without an adhesive coating, and in particular consists of such a polymer. This design ensures a long service life and minimal volume change of the cell during use.

[0049] In a preferred embodiment, the electric cell has a positive electrode selected from the group consisting of LCO electrodes, LMO electrodes, NMC electrodes, NCA electrodes, and LFP electrodes. This ensures good electron transfer.

[0050] In a preferred embodiment, the electric cell comprises at least one separator selected from the group consisting of microporous polyolefin membranes, in particular polyethylene or polypropylene membranes, and nanofiber nonwoven membranes, in particular polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), or polyethylene terephthalate (PET), optionally with a ceramic coating and / or with at least one adhesive layer. This ensures the safety of the electric cell.

[0051] In a preferred embodiment, the electrical cell according to the invention comprises several layers, in particular double-sided, coated negative and positive electrodes with an intermittent separator. In a preferred embodiment, the electrical cell according to the invention is designed as a prismatic cell, pouch cell, button cell, or cylindrical cell. This increases the durability and stability of the electrical cell.

[0052] Another aspect of the present invention is a lithium-ion battery comprising at least one negative electrode or electrical cell according to the invention. Advantageously, the lithium-ion battery has a long service life and good fast-charging capability at a high energy density.

[0053] Another aspect of the present invention is a device comprising at least one lithium-ion battery according to the invention.

[0054] In a preferred embodiment, the device comprises at least one lithium-ion battery according to the invention, a robot or an electric vehicle, for example an electric car, a hybrid vehicle or an e-bike, or an electric aircraft, for example a drone or a satellite, an electrically powered watercraft, for example a sports boat, an underwater vehicle or a model ship, or a portable device, for example a lamp or a communication and / or entertainment device, for example a telephone, a smartphone, a laptop, a notebook and a tablet.

[0055] In the context of the present invention, the term "lithium-ion battery" is understood to mean both a primary and a secondary lithium-ion battery, preferably a secondary lithium-ion battery. A primary lithium-ion battery is a non-rechargeable lithium-ion battery, and a secondary lithium-ion battery is a rechargeable lithium-ion battery.

[0056] In connection with the present invention, a "positive electrode" is understood to be the electrode that functions as a cathode (electron acceptor) during discharge and as an anode (electron donor) during charging, and a "negative electrode" is understood to be the electrode that functions as an anode during discharge and as a cathode during charging.

[0057] In connection with the present invention, an “active material” of an electrode is understood to be the material that serves to absorb or release lithium ions, in particular a lithium metal mixed oxide or lithium iron phosphate in the case of a positive electrode, or in particular silicon, graphite, or both in the case of a negative electrode.

[0058] In connection with the present invention, the term "binder" is understood to mean a single binder or a mixture of different binders as binder components; in particular, the binder comprises different binder components and optionally further additives.

[0059] In connection with the present invention, the term "polar functional group" is understood to mean a functional group by virtue of which the molecule, by virtue of having the polar functional group, exhibits an electric dipole moment, in particular a permanent one. Preferably, a polar functional group comprises an atom with a higher electronegativity than carbon. A preferred example of a polar functional group is a carboxylic acid, sulfonic acid, aldehyde, ketone, alcohol, ether, imide, amide, imine, or amine group. In connection with the present invention, "conducting black" is also referred to as carbon black. In connection with the present invention, the CAS number for carbon black is: CAS: 1333-86-4.

[0060] In connection with the present invention, a carbon nanotube is also referred to as a carbon nanotube (CNT).

[0061] In connection with the present invention, single-walled carbon nanotubes are also referred to as single-walled carbon nanotubes (SWCNT).

[0062] Further advantageous embodiments result from the dependent claims.

[0063] The invention will be explained in more detail using the figure and the example.

[0064] The figure depicts an electrical cell.

[0065] The figure shows a simplified representation of an electric cell 1. In this case, the electric cell 1 is designed as a lithium-ion cell 1. The electric cell 1 has a housing 2. In this case, the housing 2 is pouch-shaped, or rather, a flexible pouch housing 2. The electric cell 1 is accordingly designed as a pouch cell, in particular a pouch-bag cell 1. The electric cell 1 has a positive electrode 3, or cathode 3. The positive electrode 3 has a substrate 4, which in this case is an aluminum foil 4. On the substrate 4 is a coating comprising an active material for a positive electrode 6 consisting of lithium nickel manganese cobalt oxide (NMC), a binder consisting of polyvinylidene fluoride (PVDF), an additive consisting of multi-walled carbon nanotubes, and conductive carbon black.The electric cell 1 also has a negative electrode 7, or anode 7. The negative electrode 7 has a substrate 8, which in this case is a copper foil 8. A coating for a negative electrode 9 is formed on the substrate 8. The coating for a negative electrode 9 comprises an active material for a negative electrode 10, a silicon-carbon material (Si / C), where the carbon is porous carbon, and graphite, a binder, polar functional groups, and an additive, carbon nanotubes. The substrates 4 and 8 protrude from the housing 2 for electrical contact with the positive electrode 3 and the negative electrode 7, respectively. The electric cell 1 also has a separator 11, which acts between the positive electrode 3 and the negative electrode 7.The separator 11 is arranged in the housing 2 such that it spatially and electrically separates the positive electrode 3 and the negative electrode 7 from each other. The electrical cell 1 also includes a liquid electrolyte 12, which is filled into the housing 2. In this case, the electrolyte 12 contains lithium ions 13, which are shown greatly enlarged in Figure 1.

[0066] Example:

[0067] Exemplary formulations of a negative electrode according to the invention are as follows:

[0068] Recipe 1

[0069] Coating comprising a) 98 wt% active material, based on the total mass of the coating, comprising a1) 5 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 95 wt% graphite, based on the total mass of the active material, b) 1.5 wt% binder, based on the total mass of the coating, comprising b1) 1.3 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 0.2 wt% carboxymethylcellulose, based on the total mass of the coating, c) 0.50 wt% additive, based on the total mass of the coating, comprising c1) 0.49 wt% conductive carbon black, based on on the total mass of the coating, and c2) 0,01 Mass % single-walled carbon nanotubes, based on the total mass of the coating, and,

[0070] Copper foil.

[0071] The negative electrode according to the invention has a double-sided coating of formulation 6 with a loading of 188 g / m² 2 , a one-sided layer thickness of 55 pm, a theoretically determined porosity of 19%, a density of 1.70 g / cm³ 3 and a capacity of 3.64 mAh / cm² 2 on.

[0072] Recipe 2

[0073] Coating comprising a) 90 wt% active material, based on the total mass of the coating, comprising a1) 25 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 75 wt% graphite, based on the total mass of the active material, b) 5.0 wt% binder, based on the total mass of the coating, comprising b1) 3.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 2.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 5.0 wt% additive, based on the total mass of the coating, comprising c1) 4.8 wt% conductive carbon black, based on the Total mass of the coating, and c2) 0,2 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0074] Copper foil.

[0075] The negative electrode according to the invention has a double-sided coating of formulation 2 with a loading of 158 g / m² 2 , a one-sided layer thickness of 56 pm, a theoretically determined porosity of 33%, a density of 1.40 g / cm³ 3 and a capacity of 4.92 mAh / cm² 2 on.

[0076] Formulation 3 Coating consisting of a) 92 wt% active material, based on the total mass of the coating, comprising a1) 35 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 65 wt% graphite, based on the total mass of the active material, b) 7.0 wt% binder, based on the total mass of the coating, comprising b1) 4.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 3.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 1.0 wt% additive, based on the total mass of the coating, comprising c1) 0.9 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,1 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0077] Copper foil.

[0078] The negative electrode according to the invention has a double-sided coating of formulation 3 with a loading of 150 g / m² 2 , a one-sided layer thickness of 52 pm, a theoretically determined porosity of 31%, a density of 1.45 g / cm³ 3 and a capacity of 5.55 mAh / cm² 2 on.

[0079] Recipe 4

[0080] Coating comprising a) 93.5 wt% active material, based on the total mass of the coating, comprising a1) 23 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 77 wt% graphite, based on the total mass of the active material, b) 3.5 wt% binder, based on the total mass of the coating, comprising b1) 2.5 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 3.00 wt% additive, based on the total mass of the coating, comprising c1) 2.95 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,05 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0081] Copper foil.

[0082] The negative electrode according to the invention has a double-sided coating of formulation 4 with a loading of 168 g / m² 2 , a one-sided layer thickness of 54 pm, a theoretically determined porosity of 26%, a density of 1.55 g / cm³ 3 and a capacity of 5.03 mAh / cm² 2 on.

[0083] Recipe 5

[0084] Coating comprising a) 97 wt% active material, based on the total mass of the coating, comprising a1) 10 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 90 wt% graphite, based on the total mass of the active material, b) 1.5 wt% binder, based on the total mass of the coating, comprising b1) 1.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 0.5 wt% carboxymethylcellulose, based on the total mass of the coating, c) 1.0 wt% additive, based on the total mass of the coating, comprising c1) 0.95 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,05 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0085] Copper foil.

[0086] The negative electrode according to the invention has a double-sided coating of formulation 5 with a loading of 198 g / m² 2 , a one-sided layer thickness of 60 pm, a theoretically determined porosity of 21%, a density of 1.65 g / cm³ 3 and a capacity of 4.42 mAh / cm² 2 on.

[0087] Recipe 6

[0088] Coating comprising a) 94 wt% active material, based on the total mass of the coating, comprising a1) 16 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 84 wt% graphite, based on the total mass of the active material, b) 4.5 wt% binder, based on the total mass of the coating, comprising b1) 3.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 1.5 wt% carboxymethylcellulose, based on the total mass of the coating, c) 1.5 wt% additive, based on the total mass of the coating, comprising c1) 1.4 wt% conductive carbon black. based on the total mass of the coating, and c2) 0,1 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0089] Copper foil.

[0090] The negative electrode according to the invention has a double-sided coating of formulation 1 with a loading of 176 g / m² 2 , a one-sided layer thickness of 56 pm, a theoretically determined porosity of 25%, a density of 1.57 g / cm³ 3 and a capacity of 4.55 mAh / cm² 2 on.

[0091] Recipe 7

[0092] Coating comprising a) 91 wt% active material, based on the total mass of the coating, comprising a1) 50 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 50 wt% graphite, based on the total mass of the active material, b) 5.0 wt% binder, based on the total mass of the coating, comprising b1) 4.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 4.0 wt% additive, based on the total mass of the coating, comprising c1) 3.8 wt% conductive carbon black, based on the Total mass of the coating, and c2) 0,2 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0093] Copper foil.

[0094] The negative electrode according to the invention has a double-sided coating of formulation 7 with a loading of 150 g / m² 2 , a one-sided layer thickness of 58 pm, a theoretically determined porosity of 33%, a density of 1.40 g / cm³ 3 and a capacity of 6.87 mAh / cm² 2 on.

[0095] Recipe 8

[0096] Coating comprising a) 96 wt% active material, based on the total mass of the coating, comprising a1) 15 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 85 wt% graphite, based on the total mass of the active material, b) 2.0 wt% binder, based on the total mass of the coating, comprising b1) 1.0 wt% styrene-butadiene rubber substituted with acrylic acid, based on the total mass of the coating, and b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 2.0 wt% additive, based on the total mass of the coating, comprising c1) 1.7 wt% conductive carbon black. based on the total mass of the coating, and c2) 0,3 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0097] Copper foil.

[0098] The negative electrode according to the invention has a double-sided coating of formulation 8 with a loading of 175 g / m² 2 , a one-sided layer thickness of 56 pm, a theoretically determined porosity of 26%, a density of 1.55 g / cm³ 3 and a capacity of 4.42 mAh / cm² 2 on.

[0099] Recipe 9

[0100] Coating comprising a) 97 wt% active material, based on the total mass of the coating, comprising a1) 45 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 55 wt% graphite, based on the total mass of the active material, b) 2.0 wt% binder, based on the total mass of the coating, comprising b1) 1.0 wt% styrene-butadiene rubber substituted with acrylic acid, based on the total mass of the coating, and b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, c) 1.0 wt% additive, based on the total mass of the coating, comprising c1) 0.8 wt% conductive carbon black, based on on the total mass of the coating, and c2) 0,2 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0101] Copper foil. The negative electrode according to the invention has a double-sided coating of formulation 9 with a loading of 157 g / m². 2 , a one-sided layer thickness of 79 pm, a theoretically determined porosity of 52%, a density of 1.00 g / cm³ 3 and a capacity of 6.73 mAh / cm² 2 on.

[0102] Recipe 10

[0103] Coating comprising a) 95 wt% active material, based on the total mass of the coating, comprising a1) 19 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 81 wt% graphite, based on the total mass of the active material, b) 3.0 wt% binder, based on the total mass of the coating, comprising b1) 2.5 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, and b2) 0.5 wt% carboxymethylcellulose, based on the total mass of the coating, c) 2.0 wt% additive, based on the total mass of the coating, comprising c1) 1.7 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,3 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0104] Copper foil.

[0105] The negative electrode according to the invention has a double-sided coating of formulation 10 with a loading of 189 g / m² 2 , a one-sided layer thickness of 79 pm, a theoretically determined porosity of 43%, a density of 1.20 g / cm³ 3 and a capacity of 5.22 mAh / cm² 2 on. Recipe 11

[0106] Coating comprising a) 94.5 wt% active material, based on the total mass of the coating, comprising a1) 25 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 75 wt% graphite, based on the total mass of the active material, b) 4.0 wt% binder, based on the total mass of the coating, comprising b1) 4.0 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 1.5 wt% additive, based on the total mass of the coating, comprising c1) 1.4 wt% conductive carbon black, based on the total mass of the coating, and c2) 0.1 wt% single-walled carbon nanotubes, based on the Total mass of the coating, and

[0107] Copper foil.

[0108] The negative electrode according to the invention has a double-sided coating of formulation 11 with a loading of 193 g / m² 2 , a one-sided layer thickness of 64 pm, a theoretically determined porosity of 29%, a density of 1.50 g / cm³ 3 and a capacity of 6.01 mAh / cm² 2 on.

[0109] Recipe 12

[0110] Coating comprising a) 95 wt% active material, based on the total mass of the coating, comprising a1) 20 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 80 wt% graphite, based on the total mass of the active material, b) 3.5 wt% binder, based on the total mass of the coating, comprising b1) 1.5 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, and b3) 1.0 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 1.5 Mass % additive, based on the total mass of the coating,comprising c1) 1.3 wt% conductive carbon black, based on the total mass of the coating, and c2) 0.2 wt% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0111] Copper foil.

[0112] The negative electrode according to the invention has a double-sided coating of formulation 12 with a loading of 162 g / m² 2 , a one-sided layer thickness of 52 pm, a theoretically determined porosity of 26%, a density of 1.55 g / cm³ 3 and a capacity of 4.57 mAh / cm² 2 on.

[0113] Recipe 13

[0114] Coating comprising a) 93 wt% active material, based on the total mass of the coating, comprising a1) 40 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 60 wt% graphite, based on the total mass of the active material, b) 5.0 wt% binder, based on the total mass of the coating, comprising b1) 2.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, and b3) 2.0 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 2.0 wt% Additive, based on the total mass of the coating,comprising c1) 1.9 wt% conductive carbon black, based on the total mass of the coating, and c2) 0.1 wt% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0115] Copper foil.

[0116] The negative electrode according to the invention has a double-sided coating of formulation 13 with a loading of 175 g / m² 2 , a one-sided layer thickness of 60 pm, a theoretically determined porosity of 31%, a density of 1.45 g / cm³ 3 and a capacity of 6.99 mAh / cm² 2 on.

[0117] Recipe 14

[0118] Coating comprising a) 94 wt% active material, based on the total mass of the coating, comprising a1) 15 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 85 wt% graphite, based on the total mass of the active material, b) 4.5 wt% binder, based on the total mass of the coating, comprising b1) 2.0 wt% acrylic acid-substituted styrene-butadiene rubber, based on the total mass of the coating, b2) 1.0 wt% carboxymethylcellulose, based on the total mass of the coating, and b3) 1.5 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 1.5 wt% Additive, based on the total mass of the coating,comprising c1) 1.4 wt% conductive carbon black, based on the total mass of the coating, and c2) 0.1 wt% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0119] Copper foil.

[0120] The negative electrode according to the invention has a double-sided coating of formulation 14 with a loading of 178 g / m² 2 , a one-sided layer thickness of 56 pm, a theoretically determined porosity of 24%, a density of 1.60 g / cm³ 3 and a capacity of 4.50 mAh / cm² 2 on.

[0121] Recipe 15

[0122] Coating comprising a) 95 wt% active material, based on the total mass of the coating, comprising a1) 10 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 90 wt% graphite, based on the total mass of the active material, b) 3.0 wt% binder, based on the total mass of the coating, comprising b1) 1.5 wt% carboxymethylcellulose, based on the total mass of the coating, and b2) 1.5 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 2.0 wt% additive, based on the total mass of the coating, comprising c1) 1.9 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,1 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0123] Copper foil.

[0124] The negative electrode according to the invention has a double-sided coating of formulation 15 with a loading of 195 g / m² 2 , a one-sided layer thickness of 59 pm, a theoretically determined porosity of 21%, a density of 1.65 g / cm³ 3 and a capacity of 4.35 mAh / cm² 2 on.

[0125] Recipe 16

[0126] Coating comprising a) 94 wt% active material, based on the total mass of the coating, comprising a1) 23 wt% of a gas-treated silicon-carbon material, based on the total mass of the active material, wherein the carbon is a porous carbon in whose pores silicon is present, wherein the surface of the carbon is free of silicon and additionally has cavities for the expansion of the silicon, and a2) 77 wt% graphite, based on the total mass of the active material, b) 4.0 wt% binder, based on the total mass of the coating, comprising b1) 1.5 wt% carboxymethylcellulose, based on the total mass of the coating, and b2) 2.5 wt% polyacrylic acid or lithium polyacrylic acid, based on the total mass of the coating, c) 2.0 wt% additive, based on the total mass of the coating, comprising c1) 1.9 wt% conductive carbon black, based on the total mass of the coating, and c2) 0,1 mass-% single-walled carbon nanotubes, based on the total mass of the coating, and,

[0127] Copper foil.

[0128] The negative electrode according to the invention has a double-sided coating of formulation 16 with a loading of 160 g / m². 2 , a one-sided layer thickness of 55 pm, a theoretically determined porosity of 31%, a density of 1.45 g / cm³ 3 and a capacity of 4.79 mAh / cm² 2 on.

[0129] With a constant composition, increasing the loading or density leads to a higher energy density, but to a reduced fast-charging capability. The capacitance of the negative electrode according to the invention results from the loading and the specific capacitance of the active material of the coating according to the invention. The capacitance can therefore be adjusted by increasing or decreasing the loading or by modifying the coating composition according to the invention. List of reference numerals

[0130] Electrical cell

[0131] Housing

[0132] Positive electrode

[0133] substrate

[0134] Coating for a positive electrode

[0135] Active material for a positive electrode

[0136] Negative electrode

[0137] substrate

[0138] Coating for a negative electrode

[0139] Active material for a negative electrode

[0140] separator

[0141] electrolyte

[0142] Lithium ions

Claims

Patent claims 1. Coating for a negative electrode comprising a) an active material a1) a silicon-carbon material (Si / C) wherein the carbon is a porous carbon, a2) graphite, b) a binder comprising polar functional groups and c) an additive Carbon nanotubes, wherein the surface of the graphite was treated with oxygen, nitrogen, methane, ethane, propane, butane, ethene, propene and / or butene prior to use.

2. Coating according to claim 1, wherein the coating comprises 90 to 98 wt% of the anode active material, based on the total mass of the coating, in particular wherein the anode active material comprises 5 to 50 wt% of the silicon-carbon material (Si / C) and 50 to 95 wt% graphite, each based on the total mass of the active material, in particular wherein the silicon-carbon material is a gas-treated silicon-carbon material.

3. Coating according to any of the preceding claims, wherein the coating comprises 1 to 7 wt% of the binder, based on the total mass of the coating, in particular wherein the binder comprises 1 to 5 wt% of a styrene-butadiene polymer and 0.1 to 2 wt% carboxymethylcellulose, each based on the total mass of the coating, and / or the styrene-butadiene polymer comprises the functional groups and / or the functional groups are acrylic acid groups.

4. Coating according to one of the preceding claims, wherein the additive comprises 0.1 to 3 wt%, in particular 0.1 to 2 wt%, conductive carbon black and 0.01 to 0.3 wt%, carbon nanotubes, each relative to the total mass of the coating, and / or the carbon nanotubes are single-walled carbon nanotubes.

5. Coating according to any of the preceding claims, wherein the silicon is homogeneously distributed in 10 to 99% of the pores of the carbon, based on the mean number of pores of the porous carbon, and / or wherein the surface of the porous carbon of the silicon-carbon material is free of pure silicon, and / or wherein the surface of the silicon-carbon material has been treated with hydrocarbons prior to use.

6. Coating according to any of the preceding claims, wherein the graphite has a mean particle size dso of 7 to 13 pm.

7. A method for producing a negative electrode, wherein the method comprises the following process steps: x) providing a coating according to one of claims 1 to 6 and a substrate, y) coating the substrate with the coating and z) obtaining a negative electrode.

8. Negative electrode comprising a coating according to any one of claims 1 to 6 or producible according to a method according to claim 7.

9. Negative electrode according to claim 8, wherein the electrode has a loading of 150 to 200 g / m² 2 the coating, especially double-sided, and / or a density of 1.00 to 1.70 g / cm³ 3 and / or a capacity of 2.5 to 6 mAh / cm² 2 exhibits.

10. Negative electrode according to one of claims 8 or 9, wherein the substrate is a copper foil, an aluminum foil or a polymer foil coated with copper or aluminum.

11. Electric cell comprising a negative electrode according to one of claims 8 to 10, a positive electrode, an electrolyte and a separator.

12. Electric cell according to claim 11, wherein the positive electrode comprises an active material, in particular comprising lithium nickel manganese cobalt oxide, a binder, in particular comprising polyvinylidene fluoride, at least one additive, in particular comprising multi-walled carbon nanotubes and conductive carbon black, and a substrate, in particular an aluminum foil. exhibits, and the separator has a ceramic-coated polymer with or without an adhesive coating.

13. Electric cell according to one of claims 11 or 12, wherein the cell has several layers of double-sided coated negative and positive electrodes with intermittent separator and / or is designed as a prismatic cell, pouch cell or cylindrical cell.

14. Lithium-ion battery comprising at least one negative electrode according to any one of claims 8 to 10 or an electrical cell according to any one of claims 11 to 13.

15. Device comprising at least one lithium-ion battery according to claim 14.

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