Novel anode active material slurry for coating an anode current collector for a secondary li-ion battery

Patent metadata

Field	Value
Publication number	US-2025174655-A1
Application number	US-202318872996-A
Country	US
Kind code	A1
Filing date	Jun 27, 2023
Priority date	Jun 27, 2022
Publication date	May 29, 2025
Grant date	—

Abstract

Disclosed is an anode active material slurry for coating an anode current collector for a secondary Li-ion battery, comprising:
i) 80 to 98 wt. % of at least one anode active material; ii) 0 to 5 wt. % of at least one conductive material; iii) 0.1 to 5 wt. % of at least one alkali-swellable emulsion; iv) 0 to 5 wt. % of at least one latex binder; v) 0 to 5 wt. % of at least one further component selected from a specific group, and vi) at least one solvent, in particular water.

wherein the at least one alkali-swellable emulsion is an emulsion- or suspension copolymerizate of a nonionic monomer comprising butadiene, styrene or at least one (meth)acrylate monomer, and optionally acrylonitrile, and an olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt, wherein the (meth)acrylate monomer is a C 1 - to C 4 -alkyl (meth)acrylate monomer, the alkali-swellable emulsion is not hydrophobically modified.

First claim

1 . An anode active material slurry, comprises
vii) 80 to 98 wt. % of at least one anode active material; viii) 0 to 5 wt. % of at least one conductive material; ix) 0.1 to 5 wt. % of at least one alkali-swellable emulsion; x) 0 to 5 wt. % of at least one latex binder; xi) 0 to 5 wt. % of at least one further component selected from the group of dispersants, waterborne crosslinking agents, filler, proteins, polysaccharides, and their derivatives; and synthetic water-soluble polymers, and xii) at least one solvent, in particular water,
wherein the wt. % are based on their solids content in relation to the solids content of the total slurry, determined according to ASTM D3926-05 (2019),
wherein the at least one alkali-swellable emulsion is an emulsion- or suspension copolymerizate of at least one nonionic monomer comprising butadiene, styrene or at least one (meth)acrylate monomer, and optionally acrylonitrile, and at least one olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt, wherein the (meth)acrylate monomer is a C 1 - to C 4 -alkyl (meth)acrylate monomer and wherein the anode active material slurry is adapted for coating an anode current collector for a secondary Li-ion battery.

2 . The slurry according to claim 1 , wherein the anode active material comprises graphite, activated carbon, non-graphitizable carbon, soft carbon, hard carbon, mesocarbon microbeads (MCMB), silicon particulate, Si—C composite particulate, silicon oxide, silicon monoxide (SiO), silicon dioxide (SiO 2 ), tin oxide (SnO), tin dioxide (SnO 2 ), tin particulate, lithium titanate, and mixtures thereof.

3 . The slurry according to claim 1 , wherein the at least one conductive material comprises carbon black, acetylene black, ketjen black, carbon fibers, carbon nanotubes, activated carbon, graphene, petroleum coke, and mixtures thereof.

4 . The slurry according to claim 1 , wherein the at least one alkali-swellable emulsion is an emulsion- or suspension copolymerizate of at least one nonionic monomer comprising at least one (meth)acrylate monomer and optionally acrylonitrile, wherein the (meth)acrylate monomer is a C 1 - to C 4 -alkyl (meth)acrylate monomer, at least one olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt, and
at least one olefinically unsaturated crosslinking monomer (6c), and/or at least one functional monomer (6d) selected from the group of (meth)acrylates and derivative thereof, and comprising an amine-, amide-, nitrile-, hydroxyl-, glycidyl-, sulfonyl-, ethoxy-, and/or phosphorous-containing group, and derivatives thereof.

5 . The slurry according to claim 1 , wherein the at least one alkali-swellable emulsion is an emulsion or suspension copolymerizate based copolymer of
a) 30 to 79 wt. % of at least one nonionic monomer selected from the group of C 1 - to C 4 -alkyl (meth)acrylate ester; styrene, butadiene, ethylene, propylene, vinyl acetate, vinyl propionate, and acrylonitrile; b) 21 to 60 wt. % of at least one olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt; c) 0 to 10 wt. % of at least one olefinically unsaturated crosslinking monomer; d) 0 to 20 wt. % of at least one functional monomer, wherein the functional monomer is selected from the group of (meth)acrylates and derivative thereof, comprising an amine-, amide-, nitrile-, hydroxyl-, glycidyl-, sulfonyl-, ethoxy-, and/or phosphorous-containing group, and derivatives thereof;
wherein the wt. % of the at least one nonionic monomer, the at least one olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt, the at least one olefinically unsaturated crosslinking monomer, and the at least one functional monomer are based on the sum of all copolymerized monomers, and wherein the alkali-swellable emulsion-comprises less than 0.2 wt. % based on the total amount of the added monomers, of C 5 - to C 40 -alkyl (meth)acrylate, and thus is not hydrophobically modified.

6 . The slurry according to claim 5 , wherein the the at least one nonionic monomer, the at least one olefinically unsaturated carboxylic acid or olefinically unsaturated carboxylic acid salt, the at least one olefinically unsaturated crosslinking monomer, and the at least one functional monomer are selected to result in a glass transition temperature T g of the alkali-swellable emulsion when having a pH of 5, of between −20° C. and +120° C. measured according to ISO 11357-1:2016 with a heating rate of 10° C./min DSC (midpoint).

7 . The slurry according to claim 1 , wherein the optional latex binder
i) is based on monomers selected from the group of aromatic vinyl monomers; conjugated diene monomers; alkenes; ethylenically unsaturated carboxylic acids; C 1 - to C 20 -alkyl esters of (meth)acrylic acid; acrylamide and derivatives thereof; acrylonitrile; acrylonitrile and vinyl esters of C 1 - to C 20 -carboxylic acids; vinyl chloride; and mixtures thereof; and/or ii) is based on a polymer or copolymer of styrene-butadiene (SB), C 1 - to C 20 -alkyl (meth)acrylate, styrene (meth)acrylate, ethylene vinylacetate (EVA) with an ethylene content of between 5 wt. to 85 wt. % and vinyl acetate content of between 95 to 15 wt. %, ethylene propylene diene mixture (EPDM), vinyl acetate-vinyl versatate (VA/VeoVa), vinyl acetate-vinyl versatate-(meth)acrylate (VA/VeoVa/Ac), ethylene-vinyl chloride (E/VC), and/or vinyl acetate-ethylene-vinyl chloride (VA/E/VC), and mixtures thereof; and/or iii) has a glass transition temperature T g of between −40° C. and +90° C., wherein the glass transition temperature T g of copolymers is calculated according to the Fox equation.

8 . The slurry according claim 1 , wherein the slurry comprises
i) 0.1 to 5 wt. of at least one alkali-swellable emulsion with a glass transition temperature T g of between −20° and +90° C. and 0 to 0.4 wt. % latex binder; or ii) 0.1 to 5 wt. %, of at least one alkali-swellable emulsion with a glass transition temperature T g of between −20° and +120° C. and 0.5 to 5 wt. % latex binder;
wherein the glass transition temperature T g is measured according to ISO 11357-1:2016 with a heating rate of 10° C./min DSC (midpoint).

9 . An anode for a secondary Li-ion battery, wherein the anode comprises an anode active material layer coated on the anode current collector, wherein the anode active material layer is the anode active material slurry according to claim 1 when applied onto the anode current collector and dried.

10 . The anode according to claim 9 , wherein the anode current collector is based on copper foil.

11 . The anode according to claim 9 wherein the
i) anode active material layer has a thickness of between 5 μm and 5 mm, and/or a density after calendering between 1 g/cm 3 and 2 g/cm 3 ; and/or
ii) anode current collector has a thickness of between 1 μm and 1 mm;

wherein the thickness of the anode active material layer and the anode current collector is determined after calendering according to ISO 2808:2019 and the density of the anode active material layer is determined by dividing the weight of the coated anode active material layer by its volume, determined by multiplying its thickness, measured according to DIN 862/Form Al using a micrometer, with the covered area.

12 . A process to make the anode according to claim 9 for the secondary Li-ion battery by coating the anode current collector with the anode active material slurry claim 1 , wherein
a) the at least one anode active material, optionally at least one conductive material, the at least one alkali-swellable emulsion optionally at least one latex

Assignees

• Trinseo Europe Gmbh

Inventors

• Page Christian

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01M4/625

  Carbon or graphite · CPC title