CN114975939A - Water-based cathode slurry, cathode pole piece and lithium ion battery - Google Patents

Water-based cathode slurry, cathode pole piece and lithium ion battery Download PDF

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Publication number
CN114975939A
CN114975939A CN202210646524.2A CN202210646524A CN114975939A CN 114975939 A CN114975939 A CN 114975939A CN 202210646524 A CN202210646524 A CN 202210646524A CN 114975939 A CN114975939 A CN 114975939A
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polypropylene
ethylene
aqueous
copolymer
cathode
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陈爽
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Wuhan Weimei New Material Technology Co ltd
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Wuhan Weimei New Material Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/137—Electrodes based on electro-active polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The application discloses an aqueous cathode slurry, a cathode pole piece and a lithium ion battery. The aqueous cathode slurry comprises a cathode active material, an aqueous polymer, a conductive agent, an aqueous dispersant and water, wherein the aqueous polymer comprises a flexible group, and the flexible group is selected from at least one of an ethylene group and an acrylic group. The application discloses aqueous cathode slurry include the waterborne polymer for the cathode active layer obtained by its preparation has higher adhesion, stronger toughness and stronger electrolyte resistance ability, and then makes including the lithium ion battery of cathode active layer still has lower manufacturing cost when having good electrical property and mechanical properties, can effectively improve lithium ion battery's price/performance ratio.

Description

Aqueous cathode slurry, cathode pole piece and lithium ion battery
Technical Field
The application relates to the technical field of batteries, in particular to aqueous cathode slurry, a cathode pole piece prepared from the aqueous cathode slurry and a lithium ion battery comprising the cathode pole piece.
Background
With the wide application of consumer electronics and electric vehicles, lithium ion batteries with high energy density, excellent cycle performance and fast charge and discharge performance are gaining favor and attention in the market. In addition to the high requirements for battery performance, the large-scale application of lithium ion batteries also has higher and higher requirements for manufacturing cost and green manufacturing of batteries.
At present, most of the cathodes for lithium ions are organic solvent type cathodes, that is, the cathode active layer in the cathode sheet is prepared from organic solvent type cathode slurry, for example, cathode slurry of NMP (nitrogen methyl pyrrolidone) + PVDF (polyvinylidene fluoride) system. However, NMP is costly and evaporation into the atmosphere can lead to environmental pollution. In addition, NMP is a high-boiling-point organic solvent, and a large amount of energy consumption is needed in the volatilization process, so that the process cost is indirectly increased.
The cathode active layer prepared by adopting the aqueous cathode slurry can effectively reduce the cost and realize zero pollution. However, the cathode active layer prepared from the existing aqueous cathode slurry has poor toughness, so that the cathode pole piece is easy to crack or fall off powder in the manufacturing or using process of the lithium ion battery.
Disclosure of Invention
In view of the above, the present application provides an aqueous cathode slurry, which aims to solve the problem of poor toughness of a cathode active layer prepared from the existing aqueous cathode slurry.
The embodiment of the application is realized by an aqueous cathode slurry, which comprises a cathode active material, an aqueous polymer, a conductive agent, an aqueous dispersant and water, wherein the aqueous polymer comprises a flexible group, and the flexible group is selected from at least one of vinyl and propenyl.
Alternatively, in some embodiments of the present application, the aqueous cathode slurry is composed of the cathode active material, the aqueous polymer, the conductive agent, the aqueous dispersant, and water.
Optionally, in some embodiments herein, the content of the solid component in the aqueous cathode slurry is greater than or equal to 30 wt% and less than or equal to 95 wt%; and/or
Based on the total mass of solid components in the aqueous cathode slurry, the content of the aqueous polymer is 1-10 wt%, the content of the aqueous dispersant is 0.1-3 wt%, the content of the conductive agent is 0.5-10 wt%, and the content of the cathode active material is 77-98.4 wt%.
Optionally, in some embodiments herein, the aqueous polymer is selected from at least one of an ethylene-based polymer and a propylene-based polymer.
Optionally, in some embodiments herein, the vinyl polymer is selected from at least one of a copolymer of ethylene and an ester, a copolymer of ethylene and acrylic acid, and a copolymer of ethylene and an acrylate salt; and/or
The propylene-based polymer is at least one selected from a copolymer of polypropylene and maleic anhydride, a copolymer of polypropylene and maleic acid, and a polypropylene maleate copolymer.
Optionally, in some embodiments herein, the copolymer of ethylene and ester is selected from at least one of ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-methyl acrylate copolymer; and/or
The copolymer of ethylene and acrylic acid is selected from at least one of ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer; and/or
The copolymer of ethylene and acrylate is selected from at least one of polyethylene-acrylate and polyethylene-methacrylate, wherein the polyethylene-acrylate is selected from at least one of polyethylene-acrylate sodium salt, polyethylene-acrylate lithium salt, polyethylene-acrylate potassium salt, polyethylene-acrylate ammonia salt and polyethylene-acrylate amine salt, and the polyethylene-methacrylate is selected from at least one of polyethylene-methacrylate sodium salt, polyethylene-methacrylate lithium salt, polyethylene-methacrylate potassium salt, polyethylene-methacrylate ammonia salt and polyethylene-methacrylate amine salt; and/or
The copolymer of polypropylene and maleic anhydride is selected from polypropylene-maleic anhydride copolymer; and/or
The copolymer of polypropylene and maleic acid is at least one selected from polypropylene-maleic acid copolymer and polypropylene-ethylene-maleic acid copolymer; and/or
The polypropylene maleate copolymer is selected from at least one of polypropylene-maleate and polypropylene-ethylene-maleate, wherein the polypropylene-maleate is selected from at least one of polypropylene-potassium maleate, polypropylene-lithium maleate, polypropylene-sodium maleate, polypropylene-ammonia maleate and polypropylene-amine maleate, and the polypropylene-ethylene-maleate is selected from at least one of polypropylene-ethylene-potassium maleate, polypropylene-ethylene-lithium maleate, polypropylene-ethylene-sodium maleate, polypropylene-ethylene-ammonia maleate and polypropylene-ethylene-amine maleate.
Optionally, in some embodiments herein, the waterborne polymer has a molecular weight of 1 × 10 4 ～1000×10 4 。
Optionally, in some embodiments of the present application, the cathode active material is selected from at least one of lithium iron phosphate, lithium manganate, lithium iron manganese phosphate, a nickel-cobalt-manganese ternary material, and a nickel-cobalt-aluminum ternary material; and/or
The conductive agent is selected from at least one of carbon black, graphite, carbon fiber and carbon nano tube; and/or
The aqueous dispersant is at least one selected from the group consisting of sodium carboxymethylcellulose, lithium carboxymethylcellulose, polyvinylpyrrolidone, hydroxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyacrylic acid-acrylonitrile copolymer, polyacrylic acid-acrylate-acrylonitrile copolymer, methacrylic acid-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, methacrylate-acrylonitrile copolymer, polyacrylate-acrylate-acrylonitrile copolymer, and polymethacrylate-acrylate-acrylonitrile copolymer.
Correspondingly, the embodiment of the application also provides a cathode pole piece, which comprises a cathode current collector and a cathode active layer combined on at least one surface of the cathode current collector, wherein the cathode active layer is prepared from the aqueous cathode slurry.
Optionally, in some embodiments of the present application, in the cracked product of the cathode active layer cracked by using thermogravimetric-mass spectrometry, the ethylene monomer and/or the propylene monomer account for 5-95% of the total weight of the monomers in the cracked product.
Optionally, in some embodiments of the present application, the cathode active layer includes a cathode active material, an aqueous polymer, an aqueous dispersant and a conductive agent, and in the cathode active layer, the content of the aqueous polymer is 1 to 10 wt%, the content of the aqueous dispersant is 0.1 to 3 wt%, the content of the conductive agent is 0.5 to 10 wt%, and the content of the cathode active material is 77 to 98.4 wt%.
Correspondingly, the embodiment of the application also provides a lithium ion battery, and the lithium ion battery comprises the cathode pole piece.
The application of the water-based cathode slurry comprises the water-based polymer, so that a cathode active layer prepared from the water-based polymer has higher adhesive force, stronger toughness and stronger electrolyte resistance, and further the lithium ion battery comprising the cathode active layer can have excellent electrical property and mechanical property, and also has lower manufacturing cost, and the cost performance of the lithium ion battery can be effectively improved.
Detailed Description
The technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. Furthermore, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present application, are given by way of illustration and explanation only, and are not intended to limit the present application.
In the description of this application, the term "including" means "including but not limited to". Various embodiments of the present application may exist in a range of forms; it is to be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the application; accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, it is contemplated that the description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the stated range, such as 1, 2, 3, 4, 5, and 6, as applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any number (fractional or integer) recited within the indicated range.
The embodiment of the application provides an aqueous cathode slurry, which comprises a cathode active substance, an aqueous polymer, a conductive agent, an aqueous dispersant and water. Wherein, the aqueous polymer comprises a flexible group, and the flexible group can be selected from but not limited to at least one of vinyl and propenyl.
In some embodiments, the aqueous cathode slurry has a content of solid components (solid content) of 30 wt% or more and 95 wt% or less. Within the solid content range, the aqueous cathode slurry can have proper viscosity, so that the uniform dispersion of solid components is facilitated, the drying is easy during the preparation of the cathode active layer, and the preparation of the cathode active layer is facilitated. It is understood that the solid components of the aqueous cathode slurry include a cathode active material, an aqueous polymer, a conductive agent, and an aqueous dispersant.
In some embodiments, the aqueous polymer is contained in an amount of 1 to 10 wt%, the aqueous dispersant is contained in an amount of 0.1 to 3 wt%, the conductive agent is contained in an amount of 0.5 to 10 wt%, and the cathode active material is contained in an amount of 77 to 98.4 wt%, based on the total mass of solid components in the aqueous cathode slurry.
The aqueous polymer may be selected from, but not limited to, at least one of an ethylene-based polymer and a propylene-based polymer. The ethylene-based polymer has a flexible group ethylene group therein, and the propylene-based polymer has a flexible group propylene group therein. The aqueous polymer is used to improve the toughness of the cathode sheet and provide adhesion of the cathode active layer to the metal foil (current collector) and resistance to the electrolyte (i.e., electrolyte resistance).
The vinyl polymer may be selected from, but not limited to, at least one of a copolymer of ethylene and an ester, a copolymer of ethylene and acrylic acid, and a copolymer of ethylene and an acrylate salt.
In some embodiments, the copolymer of ethylene and ester may be selected from, but is not limited to, at least one of ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-methyl acrylate copolymer.
In some embodiments, the copolymer of ethylene and acrylic acid may be selected from, but is not limited to, at least one of an ethylene-acrylic acid copolymer, and an ethylene-methacrylic acid copolymer.
In some embodiments, the copolymer of ethylene and acrylate may be selected from, but is not limited to, at least one of polyethylene-acrylate, and polyethylene-methacrylate. Further, the polyethylene-acrylic acid salt may be selected from at least one of, but not limited to, polyethylene-acrylic acid sodium salt, polyethylene-acrylic acid lithium salt, polyethylene-acrylic acid potassium salt, polyethylene-acrylic acid ammonia salt, and polyethylene-acrylic acid amine salt. The polyethylene-methacrylic acid salt may be selected from at least one of, but not limited to, polyethylene-methacrylic acid sodium salt, polyethylene-methacrylic acid lithium salt, polyethylene-methacrylic acid potassium salt, polyethylene-methacrylic acid ammonia salt, and polyethylene-methacrylic acid amine salt.
Further, in some embodiments, the polyethylene-ammonium acrylate salt may be selected from, but is not limited to, polyethylene-ammonium acrylate.
Further, in some embodiments, the polyethylene-acrylic acid amine salt may be selected from, but is not limited to, polyethylene-acrylic acid methylamine, polyethylene-acrylic acid dimethylamine, polyethylene-acrylic acid trimethylamine, polyethylene-acrylic acid ethylamine, polyethylene-acrylic acid diethylamine, polyethylene-acrylic acid triethylamine salt, polyethylene-acrylic acid N-propylamine, polyethylene-acrylic acid N-butylamine, polyethylene-acrylic acid cyclohexylamine, polyethylene-acrylic acid ethylenediamine, polyethylene-acrylic acid benzylamine, polyethylene-acrylic acid aniline, polyethylene-acrylic acid N-toluidine, polyethylene-acrylic acid N, N-xylidine, polyethylene-acrylic acid diphenylamine, polyethylene-acrylic acid triphenylamine, polyethylene-acrylic acid o-toluidine, polyethylene-acrylic acid triethylamine, polyethylene-acrylic acid triphenylamine, polyethylene-acrylic acid m-toluidine, polyethylene-acrylic acid triethylamine salt, polyethylene-acrylic acid methyl amine, polyethylene-acrylic acid triethylamine salt, polyethylene-acrylic acid triethylamine, polyethylene-acrylic acid, polyethylene-N-toluidine, polyethylene-acrylic acid-N-aniline, polyethylene-acrylic acid-aniline, polyethylene-acrylic acid-N-aniline, polyethylene-acrylic acid-aniline, polyethylene-acrylic acid-styrene copolymer, polyethylene copolymer, and polyethylene copolymer, and polyethylene copolymer, and polyethylene copolymer, and polyethylene copolymer, At least one of polyethylene-m-toluidine acrylate, polyethylene-p-toluidine acrylate, polyethylene-nitroaniline acrylate, polyethylene-diethanolamine acrylate, polyethylene-triethanolamine acrylate, and polyethylene-ethanolamine acrylate.
Further, in some embodiments, the polyethylene-ammonium methacrylate salt may be selected from, but is not limited to, polyethylene-ammonium methacrylate.
Further, in some embodiments, the polyethylene-methacrylic acid amine salt may be selected from, but is not limited to, polyethylene-methyl methacrylate, polyethylene-dimethyl methacrylate, polyethylene-trimethyl methacrylate, polyethylene-ethyl methacrylate, polyethylene-diethyl methacrylate, polyethylene-triethyl methacrylate, polyethylene-N-propyl methacrylate, polyethylene-N-butyl methacrylate, polyethylene-cyclohexyl methacrylate, polyethylene-ethylene diamine methacrylate, polyethylene-benzyl methacrylate, polyethylene-aniline methacrylate, polyethylene-N-toluidine methacrylate, polyethylene-N, N-xylidine methacrylate, polyethylene-diphenylamine methacrylate, polyethylene-N-xylidine methacrylate, polyethylene-dimethylamine, polyethylene-triethylamine methacrylate, polyethylene-triethylamine, polyethylene-N-methylacrylate, polyethylene-triethylamine-methyl methacrylate, polyethylene-N-methylacrylate, polyethylene-triethylamine-N-methyl methacrylate, polyethylene-ethyl methacrylate, polyethylene-methyl methacrylate, polyethylene-ethyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene-methyl methacrylate, polyethylene, At least one of polyethylene-triphenylamine methacrylate, polyethylene-o-toluidine methacrylate, polyethylene-m-toluidine methacrylate, polyethylene-p-toluidine methacrylate, polyethylene-nitroaniline methacrylate, polyethylene-diethanolamine methacrylate, polyethylene-triethanolamine methacrylate, and polyethylene-ethanolamine methacrylate.
The propylene-based polymer may be selected from, but is not limited to, at least one of a copolymer of polypropylene and maleic anhydride, a copolymer of polypropylene and maleic acid, and a polypropylene maleate copolymer. It is understood that the polypropylene maleate copolymer is a salt formed by further reacting a copolymer of polypropylene and maleic acid formed after copolymerization of polypropylene and maleic acid, for example, in at least one embodiment, the polypropylene maleate copolymer is a salt formed by reacting a copolymer of polypropylene and maleic acid with a base (e.g., sodium hydroxide, etc.).
In some embodiments, the copolymer of polypropylene and maleic anhydride may be selected from polypropylene-maleic anhydride copolymers.
In some embodiments, the copolymer of polypropylene and maleic acid may be selected from, but not limited to, at least one of polypropylene-maleic acid copolymer, and polypropylene-ethylene-maleic acid copolymer.
In some embodiments, the polypropylene maleate copolymer may be selected from, but is not limited to, at least one of polypropylene-maleate, and polypropylene-ethylene-maleate. Wherein the polypropylene-maleic acid salt may be selected from at least one of, but not limited to, polypropylene-potassium maleate, polypropylene-lithium maleate, polypropylene-sodium maleate, polypropylene-ammonia maleate, and polypropylene-amine maleate; the polypropylene-ethylene-maleate salt may be selected from, but is not limited to, at least one of polypropylene-ethylene-potassium maleate salt, polypropylene-ethylene-lithium maleate salt, polypropylene-ethylene-sodium maleate salt, polypropylene-ethylene-ammonium maleate salt, and polypropylene-ethylene-ammonium maleate salt.
Further, in some embodiments, the polypropylene-ammonia maleate salt may be selected from, but is not limited to, polypropylene-ammonia maleate.
Further, in some embodiments, the polypropylene-amine maleate salt may be selected from, but is not limited to, polypropylene-methylamine maleate, polypropylene-dimethylamine maleate, polypropylene-trimethylamine maleate, polypropylene-ethylamine maleate, polypropylene-diethylamine maleate, polypropylene-triethylamine maleate, polypropylene-N-propylamine maleate, polypropylene-N-butylamine maleate, polypropylene-cyclohexylamine maleate, polypropylene-ethylenediamine maleate, polypropylene-benzylamine maleate, polypropylene-aniline maleate, polypropylene-N-toluidine maleate, polypropylene-N, N-xylidine maleate, polypropylene-diphenylamine maleate, polypropylene-triphenylamine maleate, polypropylene-o-toluidine maleate, polypropylene-m-toluidine maleate, polypropylene-m-toluidine, polypropylene-m-maleic acid, polypropylene-m-toluidine, polypropylene-N-maleic acid, and m-propylamine, At least one of polypropylene-m-toluidine maleate, polypropylene-p-toluidine maleate, polypropylene-nitroaniline maleate, polypropylene-diethanolamine maleate, polypropylene-triethanolamine maleate, and polypropylene-ethanolamine maleate.
Further, in some embodiments, the polypropylene-ethylene-maleic acid ammonia salt may be selected from, but is not limited to, polypropylene-ethylene-maleic acid ammonia.
Further, in some embodiments, the polypropylene-ethylene-amine maleate salt may be selected from, but is not limited to, polypropylene-ethylene-methylamine maleate, polypropylene-ethylene-dimethylamine maleate, polypropylene-ethylene-trimethylamine maleate, polypropylene-ethylene-ethylamine maleate, polypropylene-ethylene-diethylamine maleate, polypropylene-ethylene-triethylamine maleate, polypropylene-ethylene-N-propylamine maleate, polypropylene-ethylene-N-butylamine maleate, polypropylene-ethylene-cyclohexylamine maleate, polypropylene-ethylene-ethylenediamine maleate, polypropylene-ethylene-benzylamine maleate, polypropylene-ethylene-aniline maleate, polypropylene-ethylene-N-toluidine maleate, polypropylene-ethylene-methylamine maleate, polypropylene-ethylene-dimethylamine, polypropylene-ethylene-methylamine maleate, polypropylene-ethylene-methylamine-maleate, polypropylene-ethylene-dimethylamine-maleic acid, polypropylene-ethylene-ethylamine, polypropylene-ethylene-maleic acid-methylamine-maleic acid-methyl-ethyl-methyl amine, polypropylene-ethylene-maleic acid-ethyl-methyl amine, propylene-ethyl-maleic acid-ethyl-methyl amine, propylene-ethyl methyl amine, propylene-maleic acid, propylene-ethyl alcohol, propylene-methyl alcohol, propylene-ethyl alcohol, methyl alcohol, propylene-ethyl alcohol, propylene-methyl alcohol, propylene-ethyl alcohol, propylene-methyl alcohol, propylene-ethyl alcohol, propylene-methyl alcohol, and ethyl alcohol, propylene-methyl alcohol, styrene-ethyl alcohol, styrene-methyl alcohol, styrene-ethyl alcohol, styrene-methyl alcohol, styrene-methyl alcohol, styrene-ethyl alcohol, styrene-ethyl alcohol, styrene-ethyl alcohol, styrene-methyl alcohol, styrene-ethyl alcohol, styrene-methyl alcohol, styrene-ethyl alcohol, styrene-ethyl alcohol, styrene-ethyl alcohol, At least one of polypropylene-ethylene-maleic acid N, N-dimethylaniline, polypropylene-ethylene-maleic acid diphenylamine, polypropylene-ethylene-maleic acid triphenylamine, polypropylene-ethylene-maleic acid o-toluidine, polypropylene-ethylene-maleic acid m-toluidine, polypropylene-ethylene-maleic acid p-toluidine, polypropylene-ethylene-maleic acid nitroaniline, polypropylene-ethylene-maleic acid diethanolamine, polypropylene-ethylene-maleic acid triethanolamine, and polypropylene-ethylene-maleic acid ethanolamine.
In some embodiments, the waterborne polymer has a molecular weight of 1 × 10 4 ～1000×10 4 . Within the molecular weight range, the aqueous polymer can be uniformly dispersed in the aqueous cathode slurry, and a cathode active layer prepared from the aqueous cathode slurry has strong electrolyte resistance and strong adhesive force with a metal foil (current collector).
The cathode active material may be selected from, but not limited to, at least one of lithium iron phosphate, lithium manganate, lithium iron manganese phosphate, nickel cobalt manganese ternary material, and nickel cobalt aluminum ternary material. Specifically, the cathode active material may be selected from, but not limited to, LiCoO 2 、LiNiO 2 、LiMnO 2 、LiMn 2 O 4 、Li(Ni a Co b Mn c )O 2 、LiNi a Co b Al c O 2 、LiNi y Co 1-y O 2 、LiCo y Mn 1-y O 2 、LiCo y Al 1-y O 2 、LiCo y B 1-y O 2 、LiCo y Mg 1-y O 2 、LiCo y Ti 1-y O 2 、LiCo y Mo 1-y O 2 、LiCo y Sn 1-y O 2 、LiCo y Ca 1- y O 2 、LiCo y Cu 1-y O 2 、LiCo y V 1-y O 2 、LiCo y Zr 1-y O 2 、LiCo y Si 1-y O 2 、LiCo y W 1-y O 2 、LiCo y Y 1-y O 2 、LiCo y La 1- y O 2 、LiCo y Mn 1-y O 2 、LiNi y Mn 1-y O 2 、LiCoPO 4 、LiFePO 4 、LiMn y Fe 1-y PO 4 At least one of (1). Wherein a is more than 0 and less than 1, b is more than 0 and less than 1, a + b + c is 1, and y is more than 0 and less than 1.
The conductive agent may be selected from, but not limited to, at least one of carbon black, graphite, carbon fiber, and carbon nanotube.
The aqueous dispersant may be selected from, but not limited to, at least one of sodium carboxymethylcellulose, lithium carboxymethylcellulose, polyvinylpyrrolidone, hydroxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, and a polyacrylonitrile-based aqueous polymer. The aqueous dispersant is used for promoting the cathode active material, the conductive agent and the aqueous polymer to be uniformly dispersed in water.
In some embodiments, the polyacrylate salt may be selected from, but is not limited to, at least one of lithium polyacrylate, sodium polyacrylate, potassium polyacrylate, and ammonium polyacrylate.
In some embodiments, the polymethacrylate salt may be selected from, but is not limited to, at least one of lithium polymethacrylate, sodium polymethacrylate, potassium polymethacrylate, and ammonium polymethacrylate.
In some embodiments, the polyacrylonitrile-based aqueous polymer may be selected from, but is not limited to, at least one of polyacrylic acid-acrylonitrile copolymer, polyacrylic acid-acrylate-acrylonitrile copolymer, methacrylic acid-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, methacrylate-acrylonitrile copolymer, polyacrylate-acrylate-acrylonitrile copolymer, and polymethacrylate-acrylate-acrylonitrile copolymer.
In some embodiments, the aqueous cathode slurry consists of the cathode active material, the aqueous polymer, the conductive agent, the aqueous dispersant, and water.
The aqueous cathode slurry comprises the aqueous polymer and has specific components and proportions, so that a cathode active layer prepared from the aqueous cathode slurry has high adhesive force, high toughness and high electrolyte resistance.
The embodiment of the application also provides a preparation method of the aqueous cathode slurry, which comprises the following steps:
step S11: providing the cathode active material, the aqueous polymer, the conductive agent, the aqueous dispersant and water;
step S12: and mixing the cathode active material, the aqueous polymer, the conductive agent, the aqueous dispersant and water in proportion to obtain the aqueous cathode slurry.
It is to be understood that the mixing may be stirring mixing, ultrasonic mixing, and the like known in the art for mixing.
The application also provides a cathode plate, which comprises a cathode collector and a cathode active layer combined on at least one surface of the cathode collector. The cathode active layer is prepared from the aqueous cathode slurry.
In some embodiments, in the cathode active layer, the content of the aqueous polymer is 1 to 10 wt%, the content of the aqueous dispersant is 0.1 to 3 wt%, the content of the conductive agent is 0.5 to 10 wt%, and the content of the cathode active material is 77 to 98.4 wt%.
The cracked product of the cathode active layer by thermogravimetric mass spectrometry (TG-MS) contains at least one of flexible monomers such as ethylene monomers and propylene monomers (i.e., monomers corresponding to the flexible groups, for example, monomers corresponding to vinyl groups are ethylene monomers). In some embodiments, in the cracked product of the cathode active layer cracked by thermogravimetric mass spectrometry, the ethylene monomer and/or propylene monomer (i.e. the total amount of the flexible monomers in the cracked product) accounts for 5-95% of the total weight of the monomers in the cracked product, for example, 10-90%, or 15-85%, or 20-80%, or 25-75%, or 30-70%, or 35-65%, or 40-60%, or 45-90%, or 50-95%. Within the range, the cathode active layer can have high adhesion and high toughness.
The material of the cathode current collector may be selected from, but is not limited to, at least one of materials known in the art for use in cathode current collectors, such as aluminum and nickel.
The cathode active layer of the cathode pole piece is prepared from the aqueous cathode slurry, so that the cathode pole piece has high adhesive force, high toughness and high electrolyte resistance.
The embodiment of the application also provides a preparation method of the cathode plate, which comprises the following steps:
step S21: providing the aqueous cathode slurry and the cathode current collector;
step S22: and arranging the aqueous cathode slurry on the cathode current collector, and drying to obtain a cathode active layer combined with the cathode current collector, thereby obtaining the cathode pole piece.
It is understood that the method of disposing the aqueous cathode slurry on the cathode current collector may be a solution method. The solution method may be spin coating, printing, ink jet printing, blade coating, printing, dip-draw, dipping, spray coating, roll coating, casting, slit coating, strip coating, or the like.
The drying may be at least one of heating drying, cooling drying and reduced pressure drying.
It is understood that the drying may also include the steps of cold pressing, splitting.
The cathode pole piece is prepared from the aqueous cathode slurry, so that the cathode pole piece has excellent electrical and mechanical properties, and has the characteristics of low manufacturing cost and environmental protection.
The embodiment of the application also provides an electrochemical device, which comprises the cathode pole piece. The electrochemical device may be a primary battery, a secondary battery, a fuel cell, a solar cell, or a capacitor. In some embodiments, the primary battery may be a primary lithium ion battery, and the secondary lithium ion battery may be a lithium secondary battery. The lithium ion secondary battery may be, but is not limited to, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer battery, or a lithium ion polymer secondary battery.
The embodiment of the application also provides a lithium ion battery, which comprises the cathode pole piece, the anode pole piece, the electrolyte and the diaphragm. The diaphragm is positioned between the cathode pole piece and the anode pole piece, and the electrolyte is filled in gaps between the cathode pole piece and the diaphragm and between the anode pole piece and the diaphragm.
The anode piece comprises an anode current collector and an anode active material combined on the surface of the anode current collector.
The material of the anode current collector may be selected from, but not limited to, at least one of materials known in the art for an anode current collector, such as copper, nickel, stainless steel, and titanium.
The anode active material may be selected from, but not limited to, at least one of a graphite-based carbon material, a non-graphite-based carbon material, metallic lithium, alloy lithium, a silicon-based alloy, a tin-based alloy, a conductive oxide, and a conductive polymer. Wherein the conductive oxide may be selected from, but not limited to, Li x Fe 2 O 3 、Li x WO 2 、SnO、SnO 2 、PbO、PbO 2 、Pb 2 O 3 、Pb 3 O 4 、Sb 2 O 3 、Sb 2 O 4 、Sb 2 O 5 、GeO、GeO 2 、Bi 2 O 3 、Bi 2 O 4 And Bi 2 O 5 Wherein 0 < x < 1; the conductive polymer may be selected from, but not limited to, at least one of polyacetylene, polyaniline, and polythiophene.
The electrolyte comprises a solvent, cations and anions. The solvent may be selected from, but not limited to, at least one of propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl sulfoxide, acetonitrile, tetrahydrofuran, N-methylpyrrolidone, ethyl methyl carbonate, and γ -butyrolactone. The cation may be selected from, but is not limited to, Li + 、Na + And K + At least one of (a). The anion may be selected from, but is not limited to, PF 6 - 、BF 4 - 、Cl - 、Br - 、I - 、ClO 4 - 、AsF 6 - 、CH 3 CO 2 - 、CF 3 SO 3 - 、N(CF 3 SO 2 ) 2 - And C (CF) 2 SO 2 ) 3 - At least one of (1).
The lithium ion battery may be, but is not limited to, a primary lithium ion battery, a secondary lithium ion battery, a fuel lithium ion battery, and a solar lithium ion battery.
It is understood that the lithium ion battery may have a winding structure, a laminated structure, or a folded structure.
The cathode active layer in the cathode pole piece of the lithium ion battery is prepared from the aqueous cathode slurry, so that the lithium ion battery has excellent electrical property and mechanical property, and also has lower manufacturing cost, and the cost performance of the lithium ion battery can be effectively improved.
The present application will be described in detail with reference to specific examples, which are intended to be part of the present application and are not intended to limit the present application.
Example 1
Preparation of cathode plate
Adding 94.5g of lithium iron phosphate (cathode active material), 3g of conductive carbon, 2g of polyethylene-lithium acrylate (aqueous polymer), 0.5g of sodium carboxymethylcellulose (aqueous dispersant) into 100g of water, and fully stirring and uniformly mixing to obtain aqueous cathode slurry;
and coating the aqueous cathode slurry on an Al foil, drying and cold-pressing to obtain a cathode active layer combined on the surface of the Al foil, and splitting to obtain a cathode pole piece.
The thickness of the cathode active layer of this example was 200 um.
Preparation of anode plate
Adding 97.5g of active substance artificial graphite, 1.5g of binder Styrene Butadiene Rubber (SBR) and 1g of thickener carboxymethylcellulose sodium (CMC) into deionized water, and fully stirring and uniformly mixing to obtain anode slurry;
and coating the anode slurry on a Cu foil, drying and cold-pressing to obtain an anode active layer, and splitting to obtain an anode piece.
Preparation of the separator
Adding 90g of ceramic particles and 10g of acrylate binder into deionized water, uniformly mixing to prepare slurry, uniformly coating the slurry on a wet-process polyethylene base film with the thickness of 9 microns and the porosity of 45% by adopting micro gravure coating, drying by using an oven to obtain a composite porous film, and spraying a PVDF bonding coating on the surface of the composite porous film to obtain the diaphragm.
Preparation of lithium ion battery
Stacking the cathode pole piece, the diaphragm and the anode pole piece in sequence, enabling the diaphragm to be positioned between the cathode pole piece and the anode pole piece to play an isolation role, and winding to obtain a bare cell; and placing the bare cell in an outer package, injecting electrolyte, packaging, and preparing to obtain the lithium ion battery after formation.
Example 2
The present embodiment is substantially the same as embodiment 1, except that lithium manganate is used to replace the lithium iron phosphate in embodiment 1 when preparing the cathode plate of the present embodiment.
Example 3
The present embodiment is substantially the same as embodiment 1, except that lithium iron manganese phosphate is used to replace the lithium iron phosphate in embodiment 1 when the cathode plate of the present embodiment is prepared.
Example 4
The present embodiment is substantially the same as embodiment 1, except that 47.25g of lithium iron phosphate and 47.25g of lithium manganate are used to replace 94.5g of lithium iron phosphate in embodiment 1 during the preparation of the cathode plate of the present embodiment.
Example 5
The present embodiment is substantially the same as embodiment 1, except that a nickel-cobalt-manganese ternary material is used to replace the lithium iron phosphate in embodiment 1 when the cathode plate of the present embodiment is prepared.
Example 6
The present embodiment is substantially the same as embodiment 1, except that a nickel-cobalt-aluminum ternary material is used to replace the lithium iron phosphate in embodiment 1 during the preparation of the cathode plate of the present embodiment.
Example 7
This example is basically the same as example 1 except that the amount of the aqueous flexible polymer added in this example is 1g and the amount of the lithium iron phosphate added in this example is 95.5 g.
Example 8
This example is substantially the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 1.5g and the amount of the cathode active material lithium iron phosphate added was 95 g.
Example 9
This example is substantially the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 2.5g and the amount of the cathode active material lithium iron phosphate added was 94 g.
Example 10
This example is substantially the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 3g and the amount of the cathode active material lithium iron phosphate added was 93.5 g.
Example 11
This example is basically the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 5g and the amount of the cathode active material lithium iron phosphate added was 91.5 g.
Example 12
This example is basically the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 10g and the amount of the cathode active material lithium iron phosphate added was 86.5 g.
Example 13
This example is substantially the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 0.5g and the amount of the cathode active material lithium iron phosphate added in this example was 96 g.
Example 14
This example is substantially the same as example 1 except that the amount of the aqueous flexible polymer added in this example was 0.9g and the amount of the cathode active material lithium iron phosphate added in this example was 95.6 g.
Example 15
This embodiment is substantially the same as embodiment 1 except that the thickness of the cathode active layer of this embodiment is 100 um.
Example 16
This example is substantially the same as example 1 except that the thickness of the cathode active layer of this example is 300 um.
Example 17
This example is substantially the same as example 1 except that the thickness of the cathode active layer of this example is 500 um.
Example 18
This example is substantially the same as example 1 except that the thickness of the cathode active layer of this example is 1000 um.
Example 19
This example is substantially the same as example 1 except that polyethylene-acrylic acid triethylamine salt is used instead of polyethylene-acrylic acid lithium salt in example 1.
Example 20
This example is essentially the same as example 1 except that it uses a polypropylene-lithium maleate salt instead of the polyethylene-lithium acrylate salt of example 1.
Comparative example 1
This comparative example is substantially the same as example 1 except that a cathode sheet of this comparative example was prepared using polyvinylidene fluoride (PVDF, a water-insoluble polymer) instead of polyethylene-lithium acrylate in example 1, using N-methylpyrrolidone instead of water in example 1, and having a cathode active layer thickness of 100 um.
Comparative example 2
This comparative example is substantially the same as comparative example 1 except that the thickness of the cathode active layer of this comparative example is 200 um.
Comparative example 3
This comparative example is substantially the same as comparative example 1 except that the thickness of the cathode active layer of this comparative example is 300 um.
Comparative example 4
This comparative example is substantially the same as comparative example 1 except that the cathode active layer of this comparative example has a thickness of 500 um.
Comparative example 5
This comparative example is substantially the same as example 1 except that a cathode sheet of this comparative example is prepared using a polyacrylic acid-acrylonitrile-acrylate copolymer (aqueous polymer used as known in the art) instead of the polyethylene-lithium acrylate salt of example 1.
Comparative example 6
This comparative example is substantially the same as example 1 except that the cathode sheet of this comparative example was prepared using a polybutadiene-styrene copolymer (an aqueous polymer known in the art to be used) in place of the polyethylene-lithium acrylate salt of example 1.
The cathode sheets of examples 1 to 20 and comparative examples 1 to 6 were subjected to a cathode active layer thickness test, a cathode active layer adhesion test, a cathode active layer TG-MS test, and a cathode active layer double-fold dusting test. The test results are shown in Table I.
The lithium ion batteries of examples 1 to 20 and comparative examples 1 to 6 were subjected to a discharge rate test and a 25 ℃ cycle performance test. The test results are shown in Table I.
The test method is as follows:
cathode active layer thickness test: measuring the thickness of the aluminum foil, namely taking 3 pieces of aluminum foils with the size of 100mm, testing the thickness of each piece of aluminum foil by using a micrometer, uniformly testing 10 points on each piece of aluminum foil, and taking the average value of the thicknesses as the thickness of the aluminum foil; measuring the thickness of the pole pieces, namely taking 3 pole pieces (containing aluminum foils) with the size of 100 x 100mm, testing the thickness of each pole piece by using a micrometer, uniformly testing 10 points on each pole piece, and taking the average value of the thicknesses as the thickness of the pole pieces; the thickness of the cathode active layer is obtained by subtracting the thickness of the aluminum foil from the thickness of the pole piece.
Cathode active layer adhesion test: cutting the coated cathode pole piece into sample strips with the length and width of 100mm x 10mm, compounding the green adhesive with one surface of the cathode active layer, peeling the green adhesive and the aluminum foil by a tensile machine, testing 5 samples in parallel at a peeling angle of 180 degrees and a testing speed of 50mm/min, and taking an average value as the adhesive force of the cathode active layer.
Testing of the cathode active layer TG-MS: and scraping the coated cathode active layer from the cathode plate by using a blade, carrying out TG-MS test at the test temperature of 25-500 ℃, and analyzing main components of generated gas by using a mass spectrometer to obtain the ratio of main flexible monomers (ethylene monomers and/or propylene monomers) in the cracking product to the total weight of the monomers in the cracking product.
And (3) folding and powder dropping test of the cathode active layer: and folding the coated cathode pole piece along one surface of the cathode active layer at 180 degrees, visually observing the falling condition of the cathode active layer from the aluminum foil, and dividing the falling condition of the cathode active layer into non-dusting, dusting and serious dusting.
And (3) testing the discharge rate of the lithium ion battery: taking 3 lithium ion batteries of examples 1 to 20 and comparative examples 1 to 6 respectively, charging the batteries to a preset voltage at a constant current of 0.5C rate at normal temperature, then charging the batteries to 0.05C at a constant voltage under the preset voltage, then discharging the batteries at a discharge current of 2C, testing the discharge capacity of the batteries, and recording the ratio of the discharge capacity to the capacity obtained by the discharge current of 0.5C as the 2C discharge rate of the batteries.
Lithium ion battery 25 ℃ cycle performance (capacity retention rate) test: taking 3 lithium ion batteries of examples 1-20 and comparative examples 1-6 respectively, charging the batteries to a preset voltage at a constant current of 0.5C rate at 25 ℃, and then charging the batteries to 0.05C at a constant voltage of the preset voltage to obtain the initial capacity of the battery core. The circulation process is as follows: discharging to 2.5V by using 0.5C discharge current, then charging to a preset voltage by using 0.5C multiplying power with constant current, then charging to 0.05C under the preset voltage with constant voltage, repeating the process for 1000 times, averaging the residual capacities of 3 lithium ion batteries to obtain a final capacity, and dividing the final capacity by the initial capacity to obtain a capacity retention rate.
Wherein, in the test of discharge rate of lithium ion battery and the test of 25 ℃ cycle performance, the cut-off voltage of charging adopted in the test of lithium ion battery (lithium iron phosphate battery) of examples 1, 7-20 is 3.65V, the cut-off voltage of charging adopted in the test of lithium ion battery (lithium manganate battery, lithium manganate + lithium iron phosphate battery) of examples 2, 4 is 4.25V, the cut-off voltage of charging adopted in the test of lithium ion battery (lithium ferromanganese phosphate battery) of example 3 is 4.5V, and the cut-off voltage of charging adopted in the test of lithium ion battery (nickel cobalt manganese ternary battery, nickel cobalt aluminum ternary battery) of examples 5-6 is 4.35V.
Table one:
Figure BDA0003684304080000161
Figure BDA0003684304080000171
from table one, it can be seen that:
the aqueous cathode active layers of examples 1 to 12 and 15 to 20 can achieve the same or even better adhesion force as the oily cathode active layers of comparative examples 1 to 4, and do not fall off when folded in half.
The lithium ion batteries of examples 1-12, 15-20 can achieve the same or even better discharge rate test and 25 ℃ cycle performance as the lithium ion batteries of comparative examples 1-4.
The aqueous cathode active layers of examples 13 to 14 had poor adhesion and even severe dusting after folding compared to the aqueous cathode active layers of examples 1 and 7 to 12, which may be due to insufficient adhesion and toughness of the cathode active layers due to too small amount of the aqueous flexible polymers of examples 13 to 14.
The aqueous cathode active layers of examples 1 to 12 and 15 to 20 had better adhesion than the aqueous cathode active layers of comparative examples 5 to 6, and did not lose powder after being folded in half. Wherein, no powder is dropped after being folded in half, which proves that the cathode active layer prepared from the aqueous cathode slurry has better toughness.
The aqueous cathode slurry, the cathode sheet and the lithium ion battery provided in the embodiments of the present application are introduced in detail above, and the principles and embodiments of the present application are explained herein by applying specific examples, and the descriptions of the above embodiments are only used to help understand the method and the core ideas of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (12)

1. An aqueous cathode slurry characterized by: the cathode active material comprises a cathode active material, an aqueous polymer, a conductive agent, an aqueous dispersant and water, wherein the aqueous polymer comprises a flexible group, and the flexible group is selected from at least one of vinyl and propenyl.
2. The aqueous cathode slurry according to claim 1, wherein: the aqueous cathode slurry is composed of the cathode active material, the aqueous polymer, the conductive agent, the aqueous dispersant, and water.
3. The aqueous cathode slurry of claim 1 or 2, wherein:
the content of solid components in the aqueous cathode slurry is more than or equal to 30 wt% and less than or equal to 95 wt%; and/or
Based on the total mass of solid components in the aqueous cathode slurry, the content of the aqueous polymer is 1-10 wt%, the content of the aqueous dispersant is 0.1-3 wt%, the content of the conductive agent is 0.5-10 wt%, and the content of the cathode active material is 77-98.4 wt%.
4. The aqueous cathode slurry according to claim 1 or 2, wherein: the water-based polymer is at least one selected from ethylene-based polymers and propylene-based polymers.
5. The aqueous cathode slurry according to claim 4, wherein:
the vinyl polymer is at least one selected from a copolymer of ethylene and ester, a copolymer of ethylene and acrylic acid, and a copolymer of ethylene and acrylate; and/or
The propylene-based polymer is at least one selected from a copolymer of polypropylene and maleic anhydride, a copolymer of polypropylene and maleic acid, and a polypropylene maleate copolymer.
6. The aqueous cathode slurry according to claim 5, wherein:
the copolymer of ethylene and ester is selected from at least one of ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer and ethylene-methyl acrylate copolymer; and/or
The copolymer of ethylene and acrylic acid is selected from at least one of ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer; and/or
The copolymer of ethylene and acrylate is selected from at least one of polyethylene-acrylate and polyethylene-methacrylate, wherein the polyethylene-acrylate is selected from at least one of polyethylene-acrylate sodium salt, polyethylene-acrylate lithium salt, polyethylene-acrylate potassium salt, polyethylene-acrylate ammonia salt and polyethylene-acrylate amine salt, and the polyethylene-methacrylate is selected from at least one of polyethylene-methacrylate sodium salt, polyethylene-methacrylate lithium salt, polyethylene-methacrylate potassium salt, polyethylene-methacrylate ammonia salt and polyethylene-methacrylate amine salt; and/or
The copolymer of polypropylene and maleic anhydride is selected from polypropylene-maleic anhydride copolymer; and/or
The copolymer of polypropylene and maleic acid is at least one selected from polypropylene-maleic acid copolymer and polypropylene-ethylene-maleic acid copolymer; and/or
The polypropylene maleate copolymer is selected from at least one of polypropylene-maleate and polypropylene-ethylene-maleate, wherein the polypropylene-maleate is selected from at least one of polypropylene-potassium maleate, polypropylene-lithium maleate, polypropylene-sodium maleate, polypropylene-ammonia maleate and polypropylene-amine maleate, and the polypropylene-ethylene-maleate is selected from at least one of polypropylene-ethylene-potassium maleate, polypropylene-ethylene-lithium maleate, polypropylene-ethylene-sodium maleate, polypropylene-ethylene-ammonia maleate and polypropylene-ethylene-amine maleate.
7. The aqueous cathode slurry according to claim 1 or 2, wherein: the molecular weight of the aqueous polymer is 1 x 10 4 ～1000×10 4 。
8. The aqueous cathode slurry according to claim 1 or 2, wherein:
the cathode active material is selected from at least one of lithium iron phosphate, lithium manganate, lithium iron manganese phosphate, nickel cobalt manganese ternary material and nickel cobalt aluminum ternary material; and/or
The conductive agent is selected from at least one of carbon black, graphite, carbon fiber and carbon nano tube; and/or
The aqueous dispersant is at least one selected from the group consisting of sodium carboxymethylcellulose, lithium carboxymethylcellulose, polyvinylpyrrolidone, hydroxymethylcellulose, methylcellulose, ethylcellulose, hydroxypropylcellulose, polyacrylic acid, polyacrylate, polymethacrylic acid, polymethacrylate, polyacrylamide, polyacrylic acid-acrylonitrile copolymer, polyacrylic acid-acrylate-acrylonitrile copolymer, methacrylic acid-acrylonitrile copolymer, acrylate-acrylonitrile copolymer, methacrylate-acrylonitrile copolymer, polyacrylate-acrylate-acrylonitrile copolymer, and polymethacrylate-acrylate-acrylonitrile copolymer.
9. A cathode plate, including the cathode current collector and combining the cathode active layer on at least one surface of the said cathode current collector, characterized by that: the cathode active layer is prepared from the aqueous cathode slurry according to any one of claims 1 to 8.
10. The cathode sheet of claim 9, wherein: and in the cathode active layer, ethylene monomers and/or propylene monomers account for 5-95% of the total weight of the monomers in the cracked product after the thermogravimetric mass spectrometry combined cracking.
11. The cathode sheet of claim 9, wherein: the cathode active layer comprises a cathode active substance, a water-based polymer, a water-based dispersant and a conductive agent, wherein in the cathode active layer, the content of the water-based polymer is 1-10 wt%, the content of the water-based dispersant is 0.1-3 wt%, the content of the conductive agent is 0.5-10 wt%, and the content of the cathode active substance is 77-98.4 wt%.
12. A lithium ion battery, characterized by: the lithium ion battery comprises the cathode plate of any one of claims 9 to 11.
CN202210646524.2A 2022-06-08 2022-06-08 Water-based cathode slurry, cathode pole piece and lithium ion battery Pending CN114975939A (en)

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Publication number Priority date Publication date Assignee Title
CN102329538A (en) * 2011-01-25 2012-01-25 东莞新能源科技有限公司 Water-based conductive ink of a lithium-ion battery
US20200235395A1 (en) * 2017-03-31 2020-07-23 Lg Chem, Ltd. Binder composition for secondary battery, and electrode for secondary battery and lithium secondary battery which include the same
WO2020020856A1 (en) * 2018-07-24 2020-01-30 Fundación Cidetec Eco-friendly aqueous procedure to obtain high voltage cathode for li-ion batteries
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