Anode composition containing an organic sulfur binder

Abstract

The present invention relates to an aqueous anode composition comprising metal particles or fibers or carbon graphite particles or fibers and a binder comprising at least one water-soluble polymer P prepared based on an organic sulfur monomer. The present invention also relates to a method for manufacturing an anode using the aqueous composition.

Description

Technical Field

[0001] The present invention relates to an aqueous anode composition comprising metal or carbon graphite particles or fibers and a binder comprising at least one water-soluble polymer P prepared using an organic sulfur monomer. The present invention also relates to a method for manufacturing an anode using said aqueous composition.

Background Art

[0002] Anode compositions generally containing carbon or metal in particulate form associated with a binder composition are known. This binder composition must be able to effectively bind carbon or metal to a substrate to form an anode. The most common binder compositions include styrene-butadiene polymers. The composition enables fixing of the particles to the metal substrate. Therefore, the binding properties are critical when manufacturing anodes using these anode compositions. In addition, mechanical strength or electrochemical resistance is particularly required.

[0003] An easy and uniform application of the anode composition is necessary to obtain a uniform layer, limit or avoid defects on the anode surface, and result in a uniform and particularly effective conductive layer.

[0004] Generally, the binder composition also contains various additives such as thickeners, dispersants, for example cellulose derivatives. The most common cellulose derivatives are carboxymethyl cellulose, hydroxyethyl cellulose and hydroxymethyl cellulose.

[0005] These anode compositions often contain silicon to increase the capacity of the fabricated anode. During the charge-discharge cycles of a battery containing these anodes, it is common to observe strains that can cause irreversible changes in the anode, particularly as a result of the increased volume of silicon. Therefore, resistance to strain is also a desirable property.

[0006] The number of components used when preparing the anode composition should be able to be reduced.

[0007] The compatibility of the different components of the anode composition is also an important factor when preparing the anode composition and when using these compositions to prepare anodes.

[0008] Document EP3214676 discloses a pulp for preparing a secondary lithium ion battery anode containing a water-soluble polyacrylic copolymer. Document WO2014024937 describes a secondary battery anode prepared using a binder and a fluorinated sulfonated polymer. Document WO2015008626 describes a poly(meth)acrylamide binder for battery preparation having a weight average molecular weight in the range of 300,000 to 60,000,000 g / mol. Document KR20210064944 describes a copolymer made of PVDF and styrenesulfonic acid.

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0010] Conventional anode compositions are not always satisfactory. Therefore, there is a need for an anode composition that provides a solution to all or part of the problems of conventional anode compositions.

Means for Solving the Problems

[0011] Accordingly, the present invention provides an aqueous anode composition T, · having a weight average molecular weight Mw (measured by SEC) in the range of 2,000 g / mol to 1,000,000 g / mol and containing at least one water-soluble polymer P having a weight average molecular weight Mw (measured by SEC) in the range of 2,000 g / mol to 1,000,000 g / mol, prepared by the polymerization reaction of at least one organic sulfur monomer M in the presence of at least one initiator compound, and at least one binder L in a dry weight of 0.5% to 15% based on the total weight of the binder L and the material E, · at least one material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, silicon particles, and combinations thereof in a dry weight of 85% to 99.5% based on the total weight of the binder L and the material E.

[0012] In essence, in the present invention, the polymer P is prepared using a monomer M which is an organic sulfur compound. The monomer M contains non-mineral sulfur combined with at least one organic residue, preferably a hydrocarbon residue which may also contain one or more heteroatoms such as oxygen or nitrogen, or even phosphorus. Preferably, according to the present invention, the monomer M is selected from sulfonated monomer M1, sulfated monomer M2, and combinations thereof. According to the present invention, the sulfonated monomer M1 contains at least one sulfonate ion or a group of the formula SO3 - and the sulfated monomer M2 contains at least one sulfate ion or a group of the formula SO4 - More preferably, according to the present invention, the monomer M is the sulfonated monomer M1.

[0013] According to the present invention, monomer M also contains at least one polymerizable group, preferably at least one ethylenically unsaturated group, particularly a methacrylate group, acrylate group, methacrylamide group, acrylamide group, styrene group, allyl group, methallyl group, isoprenyl group, or vinyl group.

[0014] Particularly preferably, according to the present invention, the organic sulfur monomer M is selected from 2-acrylamido-2-methylpropanesulfonic acid (AMPS), allylsulfonic acid, alkylene sulfonate, alkylene aryl sulfonate, particularly styrene sulfonate, vinyl sulfonate, methallyl sulfonate, allylsulfonic acid, methallyl sulfate, allyl sulfate, 2-sulfoethyl methacrylate, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 3-sulfopropyl methacrylate, salts thereof, and combinations thereof. Preferred monomer M is the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), the sodium salt of 3-allyloxy-2-hydroxy-1-propanesulfonic acid, and sodium styrene sulfonate, particularly the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid (AMPS).

[0015] Advantageously, according to the present invention, only monomer M can be used when preparing polymer P. Preferably, according to the present invention, monomer M can be combined with at least one other monomer selected from at least one other monomer, preferably an anionic monomer, a nonionic monomer, and combinations thereof. More preferably, monomer M can be combined with at least one other anionic monomer.

[0016] Preferably, according to the present invention, monomer M can be combined with at least one other anionic monomer M3 selected from acrylic acid, methacrylic acid, acrylate, methacrylate, maleic acid, maleate, itaconic acid, itaconate, crotonic acid, crotonate, acrylic acid oligomer, and combinations thereof. More preferably, according to the present invention, monomer M can be combined with at least one other anionic monomer M3 selected from acrylic acid, methacrylic acid, acrylate, methacrylate, and combinations thereof. Preferably, according to the present invention, monomer M3 is used in an amount of 2% to 98% by weight, preferably 5% to 90% by weight, or 15% to 85% by weight, based on the total weight of the monomers.

[0017] Also, preferably, according to the present invention, monomer M can be combined with at least one other nonionic monomer M4 selected from C1-C8 esters derived from compounds derived from acids selected from vinyl acetate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, and crotonic acid (ethyl methacrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, methyl acrylate, butyl acrylate), hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, amino monomers (acrylonitrile, vinyl lactam), styrene, and combinations thereof. More preferably, according to the present invention, monomer M can be combined with at least one other nonionic monomer M4 selected from C1-C8 esters derived from compounds derived from acids selected from vinyl acetate, acrylic acid, methacrylic acid, maleic acid, itaconic acid, and crotonic acid (ethyl methacrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, methyl acrylate, butyl acrylate), hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, styrene, and combinations thereof. Even more preferably, according to the present invention, monomer M can be combined with at least one other nonionic monomer M4 selected from ethyl acrylate, methyl acrylate, butyl acrylate, styrene, and combinations thereof.

[0018] Preferably, according to the present invention, monomer M4 is used in an amount of 2% to 30% by weight, preferably 5% to 25% by weight or 10% to 20% by weight, based on the total weight of the monomers.

[0019] Preferably, according to the present invention, polymer P is prepared in the absence of an acrylamide monomer or an acrylamide derivative, particularly in the absence of acrylamide, methacrylamide, dimethacrylamide, diethylacrylamide, and N-methylolacrylamide.

[0020] Also preferably, according to the present invention, polymer P is produced in the absence of a crosslinking monomer and in the absence of a halogenated monomer, particularly in the absence of a fluorinated monomer.

[0021] Also preferably, according to the present invention, polymer P is produced using a combination of monomer M and M3, a combination of monomer M and M4, or a combination of monomer M, M3, and M4.

[0022] More preferably, according to the present invention, polymer P is produced using a combination of monomer M1 and M3, a combination of monomer M1 and M4, or a combination of monomer M1, M3, and M4.

[0023] When another monomer is used in producing polymer P, the ratio of monomer M and the additional monomer can vary greatly. Preferably, the amount of the monomer used in addition to monomer M enables the production of water-soluble copolymer P. According to the present invention, copolymer P is water-soluble. Preferably, according to the present invention, water-soluble copolymer P is produced using an anionic monomer in a majority amount by weight. Advantageously, polymer P is soluble in any amount of water at room temperature, preferably at different pH values, particularly in the pH range of 2 to 12. Preferably, according to the present invention, polymer P is -2 wt% to 100 wt%, preferably 2 wt% to 95 wt% of monomer M, preferably monomer M selected from monomer M1, monomer M2, and combinations thereof, and can be produced using the same.

[0024] More preferably, according to the present invention, polymer P is -2 wt% to 100 wt%, preferably 2 wt% to 95 wt% of monomer M, preferably monomer M selected from monomer M1, monomer M2, and combinations thereof, and It can be produced using 0 wt% to 98 wt%, preferably 5 wt% to 98 wt% of another monomer different from monomer M, preferably another monomer selected from acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, and combinations thereof.

[0025] Even more preferably, according to the present invention, polymer P 2-acrylamido-2-methylpropanesulfonic acid in an amount of 2 wt% to 100 wt%, preferably 2 wt% to 95 wt%, and 0 wt% to 98 wt%, preferably 5 wt% to 98 wt% of at least one other monomer different from monomer M, preferably another monomer selected from acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, and combinations thereof, particularly a combination of acrylic acid or methacrylic acid with ethyl acrylate or butyl acrylate.

[0026] Furthermore, far more preferably, according to the present invention, polymer P styrenesulfonate in an amount of 2 wt% to 100 wt%, preferably 2 wt% to 95 wt%, and 0 wt% to 98 wt%, preferably 5 wt% to 98 wt% of at least one other monomer different from monomer M, preferably another monomer selected from acrylic acid, methacrylic acid, ethyl acrylate, butyl acrylate, and combinations thereof, particularly a combination of acrylic acid or methacrylic acid with ethyl acrylate or butyl acrylate.

[0027] During the polymerization reaction, using a single monomer M, preferably a single monomer M1 or a single monomer M2, results in the homopolymer P1 according to the present invention. Using at least two different monomers M, preferably at least two different monomers M1 or M2, or at least one monomer M and at least one other different monomer, preferably at least one other monomer M3 or M4, results in the copolymer P2 according to the present invention. According to the present invention, the homopolymer P1 and the copolymer P2 can be used separately or combined. Thus, the composition T according to the present invention can include at least one binder L selected from among the homopolymer P1, the copolymer P2, and combinations thereof.

[0028] Preferably, according to the present invention, the polymerization reaction is carried out at a temperature above 30°C and below 130°C, preferably below 100°C, or below 90°C, or below 80°C, or below 75°C. Preferably, during the polymerization reaction for producing the polymer P, the initiator compound is selected from peroxides (e.g., hydrogen peroxide), hydroperoxides (e.g., tert-butyl hydroperoxide), persulfates (e.g., sodium persulfate, ammonium persulfate, potassium persulfate), combinations thereof, and compounds thereof with metal salts, preferably iron salts (e.g., Fe(II) or Fe(III)), copper salts (e.g., Cu(I) or Cu(II)), and metal salts selected from combinations thereof.

[0029] Preferably, according to the present invention, the polymer P is produced in a solvent selected from polar solvents, particularly water, alcohol, toluene, ketone, chlorinated solvents, esters, and combinations thereof.

[0030] Also, preferably, according to the present invention, the polymer P can be produced in the presence of a chain transfer agent, preferably in the presence of a compound selected from isopropyl alcohol, mercaptan, dodecyl-mercaptan, phosphorous acid, phosphite, hypophosphorous acid, hypophosphite, bisulfite, alkyl iodide, alkyl bromide, and combinations thereof.

[0031] According to the present invention, the polymer P may not be neutralized, or it may be partially neutralized, or it may be completely neutralized. Preferably, the polymer P is not neutralized or is partially neutralized. According to the present invention, the carboxyl groups of the polymer P can be partially neutralized at a ratio of 70 to 97 mol%, preferably 90 to 95 mol%. The polymer P can be partially or completely neutralized using at least one monovalent ion or at least one divalent ion. According to the present invention, the polymer P can be partially or completely neutralized using a combination of at least one monovalent ion and at least one divalent ion. Therefore, according to the present invention, the polymer P can be completely or partially neutralized with variable relative molar ratios of monovalent and divalent ions. Preferably, according to the present invention, the molar ratio of monovalent ion / divalent ion is composed of 90 / 10 to 10 / 90, or 80 / 20 to 20 / 80, preferably 80 / 20 to 60 / 40, for example 70 / 30 or 50 / 50.

[0032] According to the present invention, the neutralization can be carried out using a monovalent ion selected from primary amines, secondary amines, or K + , Na + , Li + , NH4 + , or an amine and combinations thereof. Preferred monovalent ions are selected from Na + , Li + , NH4 + . According to the present invention, the neutralization can also be carried out using a divalent ion selected from Ca 2+ , Zn 2+ , Mg 2+ and combinations thereof. The preferred divalent ion is Ca 2+ .

[0033] According to the present invention, the polymer P can be neutralized using at least one compound selected from NaOH, KOH, LiOH, ammonium derivatives, ammonia, ammonium hydroxide, primary amines, secondary amines, CaO, Ca(OH)2, ZnO, Zn(OH)2, MgO, Mg(OH)2, and combinations thereof. Neutralizing the polymer P using ammonia is particularly advantageous when using the composition T at a pH less than 7, preferably less than 5. According to the present invention, the polymer P can be completely or partially neutralized using a base selected from amine bases such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, α,α'-diaminoxylene, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, triethanolamine, aminomethylpropanol, or 2-amino-2-methylpropanol (AMP) and combinations thereof.

[0034] Preferably, according to the present invention, the pH of the polymer P is less than 12 or less than 11, or in the range of 2 to 12, or 5 to 11. Also preferably, according to the present invention, the pKa of the polymer P is less than 3.5, or in the range of 1.5 to 2.5.

[0035] The polymer P has a weight average molecular weight Mw (measured by SEC) in the range of 2,000 g / mol to 1,000,000 g / mol. Preferably, the polymer P has a weight average molecular weight Mw (measured by SEC) of less than 800,000 g / mol, less than 500,000 g / mol, more preferably less than 300,000 g / mol. The polymer P generally has a weight average molecular weight Mw (measured by SEC) greater than 5,000 g / mol, or greater than 15,000 g / mol, preferably greater than 50,000 g / mol, or greater than 100,000 g / mol.

[0036] Polymer P generally has a polydispersity index PI (measured by SEC) in the range of less than 4, or 1.2 to 4, or 1.5 to 4, 1.2 to 3, or 1.5 to 3, 1.2 to 2.5, or even 1.5 to 2.5.

[0037] According to the present invention, the molecular weight or mass of Polymer P is determined by size exclusion chromatography (SEC). A test portion of the polymer solution corresponding to 90 mg of dry solids is placed in a 10 mL flask. The mobile phase is added together with 0.04% dimethylformamide (DMF) until a total mass of 10 g is reached. The composition of this mobile phase is as follows: NaHCO3: 0.05 mol / L, NaNO3: 0.1 mol / L, triethanolamine: 0.02 mol / L, NaN3: 0.03% by mass. The SEC system consists of a Waters 510 isocratic pump with a flow rate set at 0.8 mL / min, a Waters 717+ sample changer, an oven containing a Waters Ultrahydrogel Column Guard precolumn with a length of 6 cm and an inner diameter of 40 mm, followed by a Waters Ultrahydrogel linear column with a length of 30 cm and an inner diameter of 7.8 mm. Detection is provided by a Waters 410 RI differential refractometer. The oven is set at a temperature of 60 °C and the refractometer is set at a temperature of 45 °C. The SEC instrument is calibrated with a series of sodium polyacrylate standards supplied by Polymer Standards Service, and the molecular weight at the peak of the peak is composed of 1,000 g / mol to 1.10 6 g / mol, and the polydispersity index is calibrated at 1.4 to 1.7. The calibration curve is linear, taking into account the correction obtained using the flow marker: dimethylformamide (DMF). The acquisition and processing of the chromatogram are performed using "PSS WinGPC Scientific" software v 4.02. The obtained chromatogram is incorporated into the region corresponding to molecular weights exceeding 250 g / mol.

[0038] Generally, according to the present invention, the binder L contains Polymer P in the form of particles.

[0039] Preferably, according to the present invention, the binder L contains 5 wt% to 100 wt%, preferably 10 wt% to 70 wt% of the polymer P.

[0040] Essentially, according to the present invention, the aqueous composition T contains at least one binder L. Advantageously, the composition T according to the present invention may not contain other binders. Also advantageously, the composition T according to the present invention may also contain at least one other binder different from the agent L, preferably selected from (meth)acrylic polymers, comb polymers, carboxymethyl cellulose (CMC), hydroxymethyl cellulose, hydroxyethyl cellulose, alginates, styrene-butadiene polymers, poly(allylamine, HCl), amylopectin, copolymers of acrylic acid and acrylonitrile, and combinations thereof.

[0041] Also advantageously, the composition T according to the present invention may also contain at least one organic acid or one inorganic acid, preferably an acid selected from sulfuric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, and combinations thereof.

[0042] Essentially, according to the present invention, the aqueous composition T contains at least one material E. Preferably, according to the present invention, the composition T contains a material E optionally doped with at least one element selected from silicon, lithium, carbon graphite or graphite-like carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, preferably selected from lithium, germanium, silicon, and combinations thereof. Preferred materials E are selected from carbon graphite, silicon, and combinations thereof.

[0043] In particular, Material E can be selected from conductive carbon compounds, furnace black, acetylene black, ketjen black, carbon nanotubes (CNT), synthetic graphite, natural graphite, hard carbon, activated carbon, carbon black, graphene, mesoporous carbon, amorphous silicon, semi-crystalline silicon, silicon oxide, silicon nanowires, tin, tin oxide, germanium, lithium titanate, materials suitable for use as anodes in lithium-ion batteries, and combinations thereof.

[0044] According to the present invention, Material E can be a conductive material or can include a material that can intercalate or accept lithium ions.

[0045] Advantageously, according to the present invention, Composition T may also contain other components. In particular, Composition T according to the present invention may also contain compounds selected from polyethylene, fluorinated bonding compounds such as polyvinylidene fluoride (PVDF), poly(vinyl-pyrrolidone), polytetrafluoroethylene (PTFE), chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), fluoroacrylate, fluorosilicone, and combinations thereof.

[0046] In Composition T, the proportions of the various components can vary. Preferably, Composition T according to the present invention, based on the total weight by dry weight of binder L and Material E, · binder L in a dry weight of 1% to 15%, and · Material E in a dry weight of 85% to 99% is included.

[0047] The present invention also provides a method for producing Composition T. The production method is - the production of binder L according to the present invention, - Addition of at least one material E selected from among metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, and combinations thereof, preferably, material E is selected from among silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from among lithium, germanium, and combinations thereof, addition, is included.

[0048] The present invention also provides a method for manufacturing an anode using the composition T according to the present invention. The anode manufacturing method includes - Applying at least one composition T according to the present invention to a substrate, - Drying the coated substrate and then calendaring it, is included.

[0049] Preferably, according to the present invention, the calendaring is performed using a press at a pressure in the range of, for example, 0.1 t / cm 2 ~2 t / cm 2 , preferably 0.2 t / cm 2 ~1 t / cm 2 .

[0050] Advantageously, according to the present invention, the substrate or current collector can be in the form of a plate, film, mesh, foam, sheet, rod, or any other morphological structure that does not significantly impair its ability to collect current. Generally, the substrate is in the form of a sheet, preferably a sheet of copper metal (Cu 0 ) or a sheet of nickel metal (Ni 0 ).

[0051] Preferably, the present invention provides a production method according to the present invention, wherein the application is carried out at a pH of less than 7, or in the range of pH 4 to 6.5. Also preferably, the present invention provides a production method according to the present invention, wherein the application of the composition T to the substrate is carried out on the metal surface up to a thickness after drying and calendaring that is less than 500 μm, preferably less than 100 μm, or less than 50 μm. Generally, according to the present invention, the thickness of the composition T after application, drying, and calendaring to the substrate exceeds 5 μm. According to the present invention, the thickness of the composition T after application, drying, and calendaring to the substrate is measured using a coating thickness gauge of 1 μm to 1,000 μm, particularly 20 μm to 30 μm. Particularly preferably, the present invention provides a production method in which the application of the composition T to the substrate is uniform. According to the present invention, the composition is applied uniformly when the particles of material E are uniformly distributed in the layer. According to the present invention, the uniformity is measured by visual inspection by direct visual observation with the naked eye. According to the present invention, the application is uniform if no aggregates are visible on the surface of the layer when viewed from the front in sunlight.

[0052] Preferably, when manufacturing the anode according to the present invention, at least one of the application steps is carried out at a pH of less than 7, preferably less than 5.

[0053] The composition T according to the present invention is applied by methods known per se. This can be applied by spraying, rolling, coating, heliogravure, or any other means of applying an aqueous formulation to the surface.

[0054] The present invention enables the production of an anode using the composition T according to the present invention. Thus, the present invention provides an anode produced according to the production method according to the present invention.

[0055] According to the present invention, the specific, advantageous, or preferred features of the composition T according to the present invention similarly clarify the specific, advantageous, or preferred production method, manufacturing method, and anode according to the present invention.

Embodiments for Carrying Out the Invention

[0056] The following examples illustrate various aspects of the present invention.

[0057] [Preparation and Characterization of Binder L Containing Polymer P1a According to the Present Invention] 50 g of a 50 wt% aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate (monomer M1b) and 850 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70°C. Then, a solution containing 0.35 g of ammonium persulfate in 10 g of deionized water is poured in at once. The temperature is maintained at 85°C for 120 minutes. After cooling to room temperature, the pH is adjusted to 6.0 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, binder L according to the present invention containing a homopolymer P1a having a weight average molecular weight Mw of 177,000 g / mol as measured by SEC in an aqueous solution with a concentration of 12 wt% is obtained.

[0058] [Preparation and Characterization of Binder L Containing Polymer P1b According to the Present Invention] 165 g of sodium styrenesulfonate (monomer M1a) dissolved in 310 g of deionized water is introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 85°C. Then, a solution containing 0.7 g of ammonium persulfate in 10 g of deionized water is poured in at once. The temperature is maintained at 90°C for 90 minutes. After cooling to room temperature, the pH is adjusted to 8.5 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, binder L according to the present invention containing a homopolymer P1b having a weight average molecular weight Mw of 183,500 g / mol as measured by SEC in an aqueous solution with a concentration of 25 wt% is obtained.

[0059] [Preparation and Characterization of Binder L Containing Polymer P1c According to the Present Invention] Dissolve 247 g of sodium styrenesulfonate (monomer M1a) in 464 g of deionized water and introduce it into a 1 L glass reactor by mechanical stirring and oil bath heating. Heat this to 85 °C. Then, pour a solution containing 2.2 g of ammonium persulfate into 16 g of deionized water all at once. Maintain the temperature at 90 °C for 90 minutes. After cooling to room temperature, adjust the pH to 8.5 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, a binder L according to the present invention is obtained, which contains a homopolymer P1c with a weight average molecular weight Mw of 108,000 g / mol as measured by SEC in an aqueous solution with a concentration of 33 wt%.

[0060] [Preparation and Property Evaluation of Binder L Containing Polymer P1d According to the Present Invention] Introduce 50 g of isopropanol and 150 g of deionized water into a 1 L glass reactor by mechanical stirring and oil bath heating. Heat this to reflux at 81 °C. Then, using two pumps, inject the following in parallel over 120 minutes. - A solution containing 20 g of ammonium persulfate in 30 g of deionized water - A solution containing 243 g of sodium styrenesulfonate (monomer M1a) and 566 g of deionized water.

[0061] Then, separate the isopropanol by distillation. After cooling to room temperature, add deionized water and adjust the pH to 8.3 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, a binder L according to the present invention is obtained, which contains a homopolymer P1d with a weight average molecular weight Mw of 10,000 g / mol as measured by SEC in an aqueous solution with a concentration of 27 wt%.

[0062] [Preparation and Property Evaluation of Binder L Containing Polymer P2a According to the Present Invention] A 50 wt% aqueous solution of 50 g of sodium 2-acrylamido-2-methylpropanesulfonate (monomer M1b), 60 g of acrylic acid (monomer M3a), 15 g of ethyl acrylate (monomer M4a) and 805 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70 °C. Then, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. Again, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 6.0 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, the binder L according to the present invention is obtained, which contains a copolymer P2a having a weight average molecular weight Mw of 158,000 g / mol as measured by SEC in an aqueous solution with a concentration of 11.1 wt%.

[0063] [Preparation and property evaluation of binder L containing polymer P2b according to the present invention] 75 g of acrylic acid (monomer M3a), 25 g of sodium styrenesulfonate (monomer M1a) and 805 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70 °C. Then, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. Again, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 6.3 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, the binder L according to the present invention is obtained, which contains a copolymer P2b having a weight average molecular weight Mw of 181,000 g / mol as measured by SEC in an aqueous solution with a concentration of 11.3 wt%.

[0064] [Preparation and property evaluation of binder L containing P2c polymer according to the present invention] 25 g of sodium styrene sulfonate (monomer M1a), 60 g of acrylic acid (monomer M3a), 15 g of ethyl acrylate (monomer M4a) and 830 g of deionized water are introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 70 °C. Then, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. Again, a solution containing 0.35 g of ammonium persulfate is poured all at once into 10 g of deionized water. The temperature is maintained at 85 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 5.8 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, the binder L according to the present invention is obtained, which contains a copolymer P2c having a weight average molecular weight Mw of 165,000 g / mol as measured by SEC in an aqueous solution having a concentration of 11.2 wt%.

[0065] [Preparation and Characterization of Binder L Containing Polymer P2d According to the Present Invention] 300 g of deionized water is introduced into a 1 L glass reactor by mechanical stirring and oil bath heating. This is heated to 94 °C. Then, the following are injected in parallel over 120 minutes using two pumps. - A solution containing 8 g of ammonium persulfate in 50 g of deionized water, - A solution containing 206 g of acrylic acid (monomer M3a), 36.4 g of sodium styrene sulfonate (monomer M1a) and 50 g of deionized water.

[0066] The temperature is maintained at 94 °C for 60 minutes. After cooling to room temperature, the pH is adjusted to 8.7 by adding a 50 wt% aqueous sodium hydroxide solution. Thereby, the binder L according to the present invention is obtained, which contains a copolymer P2d having a weight average molecular weight Mw of 26,800 g / mol as measured by SEC in an aqueous solution having a concentration of 38.5 wt%.

[0067] [Preparation of Aqueous Anode Composition T According to the Present Invention] An aqueous composition containing 5% of polymer P2a by dry weight and 5% of carbon black (Black C65 "Imerys") by dry weight is prepared with binder L (11.1% by weight) containing polymer P2a while stirring at 3,000 rpm for 2 hours using a stirrer equipped with a 40 mm disk wheel.

[0068] Next, this aqueous composition of 0.32 g of carbon black and P2a polymer, 1.2 g of silicon particles (SI-100, 30 - 50 nm, "Get Nano Materials") and deionized water is introduced into a glass beaker while stirring at 4,500 rpm for 1 hour using a stirrer equipped with a 25 mm disk wheel. A mixture of 6.32 g of graphite (92.5% by weight of GHDR, 5% by weight of SFG15L, 2.5% by weight of KS6L, "Imerys") and deionized water is added. Stirring is continued for 1 hour. Then, 0.4 g of styrene-butadiene bound latex (SNR BM-451B "Zeon" latex, 40% by weight) is added and stirred at 500 rpm for 30 minutes. The amount of water added is specified to obtain the aqueous anode composition T2a according to the present invention having a final concentration of 44.6% by dry weight.

[0069] The aqueous anode compositions T2b - T2d according to the present invention are prepared in a similar manner and have a final concentration of 44.6% by dry weight as well. Each of these contains binder L according to the present invention containing copolymers P2b - P2d.

[0070] [Manufacture and Property Evaluation of Anode According to the Present Invention] A copper plate with a thickness of 100 μm is coated with a layer of composition T1a according to the present invention with a thickness of 20 μm using a manual application bar. A disk with a diameter of 15 mm is cut out using a precision cutter. The coated disk is calendered at 0.6 t / cm2 using a press. Then, the disk is dried in an oven and the temperature is gradually raised to 110 °C over 18 hours under vacuum.

[0071] After cooling to room temperature, the uniformity of the layer is evaluated by visual inspection. In daylight, no aggregates or surface irregularities are visible on the surface of the layer when viewed from the front.

[0072] Next, the density of the obtained anode is measured by weighing it on a balance, and then its porosity is calculated.

[0073] Anodes are similarly fabricated and characterized using aqueous anode compositions T2b - T2d. The results are shown in Table 1.

[0074]

Table 1

[0075] Thus, the aqueous anode composition containing the binder according to the present invention enables the production of an anode that is stable and in which the active material binds well to the copper layer. The anode composition according to the present invention enables the production of an anode having a uniform layer. Therefore, these anodes can be easily used for manufacturing rechargeable cells or secondary batteries.

[0076] [Manufacture and Characterization of Half-Cells Containing Anodes According to the Present Invention] In a glove box (「MBraun LabStar」) maintained in an inert atmosphere (Ar, O2 and H2O < 0.5 ppm), an electrolyte (1 M, LiPF6 in a mixture of ethylene carbonate - ethyl methyl carbonate containing 2% vinyl carbonate and 10% fluoroethylene carbonate, 「Solvionic」), an anode according to the present invention, a pre-cut lithium disk (diameter 15.6 mm and thickness 0.25 mm), then a separator disk (「Whatman」 GF / C 1822 - 849, diameter 17 mm, thickness 0.26 mm, pore size 1.2 μm) and a separator disk (「Celgard」 2325 three-layer PE / PP / PE) are assembled onto the working electrode.

[0077] The half-cell containing the anode according to the present invention produced by the aqueous anode composition T2a is subjected to charge and discharge cycles in a chamber with a thermostat at 25 °C as follows. - 2 cycles: Discharge to 0.005 V at C / 7 with a C / 100 cut-off, then charge at C / 7 with a 1.0 V cut-off. - 3 cycles: Discharge to 0.005 V at C / 5 with a C / 50 cut-off, then charge at C / 5 with a 1.0 V cut-off. - 102 cycles: Discharge to 0.005 V at 1C with a C / 40 cut-off, then charge at 1C with a 1.0 V cut-off.

[0078] The half-cell containing the anode according to the present invention is similarly produced and characterized by the aqueous anode compositions T2b to T2d. For each half-cell, the charge (load), capacity, initial Coulombic efficiency (ICE), Coulombic efficiency after 10 cycles and then after 20 cycles (CE10, CE20), Coulombic cycle efficiency - CCE1, and capacity retention ratios with respect to the first cycle after 10 cycles and then after 20 cycles (CR10, CR20) are determined. The results are shown in Table 2.

[0079]

Table 2

[0080] The binder according to the present invention is very effective for obtaining anodes and cells having a high silicon concentration and enables the production of aqueous anode compositions that particularly arouse interest in electrochemical properties.

Claims

1. An aqueous anode composition T, comprising: - At least one water-soluble polymer P having a weight average molecular weight Mw (measured by SEC) in the range of 2,000 g / mol to 1,000,000 g / mol, prepared by the polymerization reaction of at least one organic sulfur monomer M in the presence of at least one initiator compound, and at least one binder L in a dry weight of 0.5% to 15% based on the total weight of the binder L and the material E; - At least one material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, silicon particles, and combinations thereof, in a dry weight of 85% to 99.5% based on the total weight of the binder L and the material E. Composition T.

2. The monomer M is selected from sulfonated monomer M1, sulfonated monomer M2, and combinations thereof, or only monomer M is used when preparing the polymer P. Preferably, the organic sulfur monomer M is 2-acrylamido-2-methylpropanesulfonic acid (AMPS), allylsulfonic acid, alkylene sulfonate, alkylene aryl sulfonate, especially styrene sulfonate, vinyl sulfonate, methallyl sulfonate, allylsulfonic acid, methallyl sulfate, allyl sulfate, 2-sulfoethyl methacrylate, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 3-sulfopropyl methacrylate, salts thereof, and combinations thereof. The composition T according to claim 1.

3. - The monomer M is combined with at least one other anionic monomer M3 selected from acrylic acid, methacrylic acid, acrylate, methacrylate, maleic acid, maleate, itaconic acid, itaconate, crotonic acid, crotonate, acrylic acid oligomer, and combinations thereof, or - The monomer M is selected from vinyl acetate; compounds derived from acids selected from acrylic acid, methacrylic acid, maleic acid, itaconic acid, and crotonic acid C １ - C ８ esters (e.g., ethyl methacrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, methyl acrylate, butyl acrylate), hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, amino monomers (e.g., acrylonitrile, vinyl lactam), styrene, and at least one other nonionic monomer M4 selected from combinations thereof, or - The polymer P is - 2% to 100% by weight, preferably 2% to 95% by weight, of monomer M, preferably monomer M1, monomer M2, and monomer M selected from combinations thereof, and - 0% to 98% by weight, preferably 5% to 98% by weight, of another monomer different from monomer M, preferably another monomer selected from monomer M3, monomer M4, and combinations thereof, prepared using, or - Polymer P is produced in the presence of at least one initiator compound selected from the group consisting of peroxides (e.g., hydrogen peroxide), hydroperoxides (e.g., tert-butyl hydroperoxide), persulfates (e.g., sodium persulfate, ammonium persulfate, potassium persulfate), combinations thereof, and their compounds with metal salts, preferably metal salts selected from iron salts (e.g., Fe(II) or Fe(III)), copper salts (e.g., Cu(I) or Cu(II)), and combinations thereof, or - Polymer P is produced in the presence of a chain transfer agent, preferably in the presence of a compound selected from isopropyl alcohol, mercaptan, dodecyl-mercaptan, phosphorous acid, phosphite, hypophosphorous acid, hypophosphite, bisulfite, alkyl iodide, alkyl bromide, and combinations thereof, or - The polymer P is unneutralized, or the polymer P is partially or fully neutralized, preferably neutralized using at least one compound selected from NaOH, KOH, LiOH, ammonium derivatives, ammonia, ammonium hydroxide, primary amines, secondary amines, CaO, Ca(OH) ２ , ZnO, Zn(OH) ２ , MgO, Mg(OH) ２ and neutralized using at least one compound selected from these combinations, or - The pH of Polymer P is less than 12 or less than 11, or is in the range of 2 to 12 or 5 to 11, or - The pKa of Polymer P is less than 3.5 or is in the range of 1.5 to 2.5, Composition T according to one of claims 1 or 2.

4. - Polymer P has a weight average molecular weight Mw (measured by SEC) of less than 800,000 g / mol, less than 500,000 g / mol, more preferably less than 300,000 g / mol, or - Polymer P has a weight average molecular weight Mw (measured by SEC) greater than 5,000 g / mol or greater than 15,000 g / mol, preferably greater than 50,000 g / mol or greater than 100,000 g / mol, Composition T according to one of claims 1 to 3.

5. Composition T according to one of claims 1 to 4, comprising at least one binder L selected from homopolymer P1, copolymer P2, and combinations thereof.

6. Composition T according to one of claims 1 to 5, comprising at least one organic acid or at least one inorganic acid, preferably an acid selected from sulfuric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, acetic acid, and combinations thereof.

7. Material E is selected from silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from lithium, germanium, and combinations thereof, the composition T according to one of claims 1 to 6.

8. The composition T according to one of claims 1 to 7, which does not contain other binders or further contains at least one other binder different from the agent L, preferably another binder selected from (meth)acrylic polymers, copolymer polymers, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, alginate, styrene-butadiene polymers, poly(allylamine, HCl), amylopectin, and combinations thereof.

9. The composition T according to one of claims 1 to 8, further comprising a compound selected from polyethylene, fluorinated binding compounds, such as polyvinylidene fluoride (PVDF), poly(vinyl-pyrrolidone), polytetrafluoroethylene (PTFE), chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), polychlorotrifluoroethylene (PCTFE), fluoroacrylate, fluorosilicone, and combinations thereof.

10. Based on the total weight of the binder L and the material E, ・Binder L in a dry weight of 1% to 15%, and ・Material E in a dry weight of 85% to 99% The composition T according to one of claims 1 to 8, which contains.

11. - Preparation of the binder L according to one of claims 1 to 6, - Addition of at least one material E selected from metal fibers, metal particles, carbon graphite fibers, carbon graphite particles, and combinations thereof, preferably, the material E is selected from silicon, lithium, carbon graphite or graphite carbon, hexagonal carbon, rhombohedral carbon, and combinations thereof, and optionally, preferably doped with at least one element selected from lithium, germanium, and combinations thereof, the addition. The method for preparing the aqueous composition T according to claims 1 to 10, which contains.

12. A method for manufacturing an anode, - Applying at least one composition T according to one of claims 1 to 10 to a substrate, - Drying the coated substrate and then calendaring it, A manufacturing method comprising.

13. - The application is carried out at a pH less than 7 or in the range of pH 4 to 6.5, or - The application of composition T to the substrate is carried out up to the thickness after drying and calendaring and is measured using a coating thickness gauge of 1 μm to 1,000 μm, i.e., less than 500 μm, preferably less than 100 μm or less than 20 μm, or - The application of composition T to the substrate is carried out up to the thickness after drying and calendaring and is measured using a coating thickness gauge of 1 μm to 1,000 μm, i.e., greater than 5 μm, or - The application of composition T to the substrate is uniform, the manufacturing method according to claim 12.

14. An anode produced according to the manufacturing method according to one of claims 12 or 13.

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