CN112952092B - Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery - Google Patents
Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery Download PDFInfo
- Publication number
- CN112952092B CN112952092B CN201911260132.7A CN201911260132A CN112952092B CN 112952092 B CN112952092 B CN 112952092B CN 201911260132 A CN201911260132 A CN 201911260132A CN 112952092 B CN112952092 B CN 112952092B
- Authority
- CN
- China
- Prior art keywords
- component
- positive electrode
- monomer
- binder
- slurry
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- 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
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
-
- 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
- H01M4/623—Binders being polymers fluorinated polymers
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Abstract
The present disclosure relates to a positive electrode binder, the binder comprising a first component and a second component; the first component is a copolymer of vinylidene fluoride and a first monomer, and the first monomer is one or more of C2-C8 olefin and C2-C4 halogenated olefin except the vinylidene fluoride; the second component is a copolymer of an acrylonitrile monomer and a second monomer, the acrylonitrile monomer is acrylonitrile and/or methacrylonitrile, and the second monomer is one or more of an acrylamide monomer, an acrylic monomer and a heterocyclic nitrogen monomer; the weight ratio of the first component to the second component is (1:4) - (4:1). The slurry containing the positive electrode binder of the present disclosure has good anti-gelation properties.
Description
Technical Field
The disclosure relates to the field of lithium ion batteries, in particular to a positive electrode binder, a preparation method thereof, positive electrode slurry, a positive electrode and a lithium ion battery.
Background
The binder for lithium ion batteries conventionally comprises an oily system for the positive electrode, which is usually solvent NMP (N-methylpyrrolidone), and an aqueous system for the negative electrode, with PVDF (polyvinylidene fluoride) being the binder. In recent years, due to the excellent performances of PVDF in electrochemical stability, adhesion, lithium ion migration capability, thermal stability and the like, the demand of the binder for the positive electrode of the lithium ion battery is substantially satisfied. However, with the increasing demand for energy density of lithium ion batteries, nickel-rich ternary positive electrode materials (LiNi) x Co y W z O 2 W is Mn, al, etc. and x + y + z = 1) becomes a development trend, and the higher the nickel content in li-ni-co-Mn oxygen, the stronger the basicity of the material, since the PVDF molecular chain will be stripped of HF molecules in a strongly basic environment, and continuous double bonds are formed on the molecular chain, and there may be double bond breakage and cross-linking with other molecular chainsAs a result, the slurry is easy to gel, and normal batching, coating and subsequent processes are affected.
The existing method is to obtain modified PVDF by adding a small amount of special monomers such as chlorotrifluoroethylene, hexafluoropropylene, tetrafluoroethylene, vinyl monomers containing carboxyl and the like during the polymerization of PVDF, thereby reducing the chain reaction of HF removal of PVDF molecular chains. However, when the nickel content of the ternary cathode material exceeds 80% (based on the total mass of nickel, cobalt and manganese elements), the slurry prepared by using the modified PVDF as a binder still easily gels.
Disclosure of Invention
The purpose of the present disclosure is to overcome the problem that the existing positive electrode binder slurry is easy to gel, and provide a positive electrode binder, a preparation method thereof, a positive electrode slurry, a positive electrode and a lithium ion battery.
In order to achieve the above object, a first aspect of the present disclosure provides a positive electrode binder including a first component and a second component; the first component is a copolymer of vinylidene fluoride and a first monomer, and the first monomer is one or more of C2-C8 olefin and C2-C4 halogenated olefin except the vinylidene fluoride; the second component is a copolymer of an acrylonitrile monomer and a second monomer, the acrylonitrile monomer is acrylonitrile and/or methacrylonitrile, and the second monomer is one or more of an acrylamide monomer, an acrylic monomer and a heterocyclic nitrogen monomer; the weight ratio of the first component to the second component is (1:4) - (4:1).
Optionally, the vinylidene fluoride is present in an amount of 30 to 90 wt%, based on the total weight of the first component;
the acrylonitrile monomer is present in an amount of 50 to 85 weight percent, based on the total weight of the second component.
Optionally, the weight ratio of the first component to the second component in the binder is (3:7) - (7:3).
Optionally, the first component has a weight average molecular weight of 80 to 140 ten thousand and the second component has a weight average molecular weight of 20 to 100 ten thousand.
Optionally, the C2-C8 olefin comprises one or more of ethylene, propylene, butylene, isobutylene, styrene and butadiene;
the C2-C4 halogenated olefin comprises one or more of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and 2,3,3,3-tetrafluoropropene;
the acrylamide monomer comprises one or more of methacrylamide, N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-methacrylamide and N, N-dimethylacrylamide;
the acrylic monomer comprises one or more of methacrylic acid, acrylic acid, crotonic acid and 2-ethyl acrylic acid;
the nitrogen heterocyclic monomer comprises one or more of 2-vinylpyridine, 4-vinylpyridine and N-vinylpyrrolidone.
A second aspect of the present disclosure provides a method of preparing the binder provided by the first aspect of the present disclosure, the method comprising: (1) In the presence of a first chain transfer agent, a first initiator and a dispersant, carrying out a first polymerization reaction on vinylidene fluoride and the first monomer in a first solvent, and removing the first solvent to obtain the first component; (2) In the presence of a second chain transfer agent, a second initiator and an emulsifier, carrying out a second polymerization reaction on an acrylonitrile monomer and the second monomer in a second solvent, and removing the second solvent to obtain a second component; (3) mixing the first component and the second component.
Optionally, the conditions of the first polymerization reaction include: inert atmosphere at 25-100 deg.C and 3-8MPa for 4-8 hr;
the conditions of the second polymerization reaction include: inert atmosphere at 40-80 deg.C and normal pressure for 2-24 hr.
Optionally, the first solvent and the second solvent are each independently selected from at least one of deionized water, N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, and pyridine;
the first chain transfer agent and the second chain transfer agent are respectively and independently selected from one or more of ethyl acetate, butyl acetate, acetone, diethyl carbonate, methyl tert-butyl ether, isopropanol, ethanol, methanol and dodecyl mercaptan;
the first initiator and the second initiator are respectively and independently selected from one or more of diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-tert-butane peroxide, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, succinyl peroxide and di (2-ethylhexyl) peroxydicarbonate;
the dispersing agent is selected from one or more of methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, sodium polyacrylate and polyvinylpyrrolidone;
the emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium lauryl sulfate, sodium laurate and polyoxyethylene lauryl sodium sulfate.
A third aspect of the present disclosure provides a positive electrode slurry for a lithium ion battery, including the positive electrode binder provided in the first aspect of the present disclosure.
Optionally, the slurry further comprises a positive electrode active material, a conductive agent and a solvent; in the slurry, the content of the positive electrode binder is 1-5 wt% of the total weight of solid matters in the slurry.
Optionally, the positive active material comprises a ternary positive active material LiNi x Co y W z O 2 W is Mn and/or Al, and x + y + z =1,x is 0.8 or more.
Optionally, the ratio of the viscosity of the positive electrode slurry after 48 hours to the viscosity of the positive electrode slurry after 0 hours is 1 to 2.
The fourth aspect of the present disclosure provides a lithium ion battery anode, which includes a current collector and a coating layer covering the current collector, wherein the coating layer is prepared from the anode slurry provided by the second aspect of the present disclosure.
Optionally, the peel force between the coating and the current collector is 15-50N/m.
A fifth aspect of the present disclosure provides a lithium ion battery comprising the lithium ion battery positive electrode provided by the fourth aspect of the present disclosure.
Through the technical scheme, the positive electrode binder disclosed by the invention contains two copolymers with specific compositions, and has good alkali resistance. When the nickel-based ternary positive electrode material is used in a high-nickel ternary positive electrode material system, the slurry is not easy to gel, and meanwhile, the flexibility of a pole piece and the adhesion of a positive electrode material to a current collector can be improved.
Additional features and advantages of the disclosure will be set forth in the detailed description which follows.
Detailed Description
The following describes in detail specific embodiments of the present disclosure. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.
A first aspect of the present disclosure provides a positive electrode binder, the binder including a first component and a second component; the first component is a copolymer of vinylidene fluoride and a first monomer, and the first monomer is one or more of C2-C8 olefin and C2-C4 halogenated olefin except the vinylidene fluoride; the second component is a copolymer of an acrylonitrile monomer and a second monomer, the acrylonitrile monomer is acrylonitrile and/or methacrylonitrile, and the second monomer is one or more of an acrylamide monomer, an acrylic monomer and a heterocyclic nitrogen monomer; the weight ratio of the first component to the second component is (1:4) - (4:1).
According to the present disclosure, by using the first component and the second component having a specific monomer composition in combination and defining the use amount ratio of the first component and the second component, a slurry having a good anti-gelation effect can be obtained, and when the binder of the present disclosure is used for a positive electrode sheet, the positive electrode sheet has good adhesion and flexibility.
In accordance with the present disclosure, the amount of vinylidene fluoride may vary over a wide range, preferably from 30 to 90 weight percent, more preferably from 60 to 90 weight percent, based on the total weight of the first component; the acrylonitrile monomer content may vary widely, preferably from 50 to 85% by weight, more preferably from 60 to 80% by weight, based on the total weight of the second component. Within the above range, the content of the monomer in the first component and the second component in the binder is appropriate, which can further reduce the binder slurry gelation phenomenon, and further improve the adhesion of the positive electrode material to the positive electrode current collector and the flexibility of the positive electrode.
In a preferred embodiment, the weight ratio of the first component to the second component in the binder may be (3:7) - (7:3), more preferably (3:7) - (5:5). The adhesive compounded by the first component and the second component within the range has better alkali resistance and adhesion, and has better gelation resistance.
In accordance with the present disclosure, the weight average molecular weight of the first component and the second component may vary over a wide range, preferably the weight average molecular weight of the first component is from 80 to 140 ten thousand, more preferably from 90 to 120 ten thousand, and the weight average molecular weight of the second component is from 20 to 100 ten thousand, more preferably from 60 to 90 ten thousand.
In accordance with the present disclosure, the C2-C8 olefins may include one or more of ethylene, propylene, butylene, isobutylene, styrene, and butadiene. The C2-C4 haloolefin may include one or more of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and 2,3,3,3-tetrafluoropropene. The acrylamide monomer can comprise one or more of methacrylamide, N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-methacrylamide and N, N-dimethylacrylamide. The acrylic monomer can comprise one or more of methacrylic acid, acrylic acid, crotonic acid and 2-ethyl acrylic acid; the nitrogen heterocyclic monomer can comprise one or more of 2-vinyl pyridine, 4-vinyl pyridine and N-vinyl pyrrolidone.
A second aspect of the present disclosure provides a method for preparing the binder provided by the first aspect of the present disclosure, the method comprising:
(1) In the presence of a first chain transfer agent, a first initiator and a dispersant, carrying out a first polymerization reaction on vinylidene fluoride and a first monomer in a first solvent, and removing the first solvent to obtain a first component;
(2) In the presence of a second chain transfer agent, a second initiator and an emulsifier, carrying out a second polymerization reaction on an acrylonitrile monomer and a second monomer in a second solvent, and removing the second solvent to obtain a second component;
(3) The first component and the second component are mixed.
According to the method, the binder with good anticoagulation property and cohesiveness can be prepared simply and efficiently, and the adhesion of the positive active material and the positive current collector and the flexibility of the pole piece can be improved when the binder is used for preparing the positive pole piece.
The method for removing the solvent in step (1) and step (2) is conventionally employed by those skilled in the art according to the present disclosure, and for example, the solvent may be removed by filtration or evaporation. After the solvent is removed, the substance after the solvent is removed can be washed and dried to obtain the first component and the second component with good physicochemical properties. The washing and drying processes are well known to those skilled in the art and will not be described in detail herein.
In a preferred embodiment, step (1) may comprise: blowing inert gas into a closed polymerization reactor to remove oxygen, adding a first solvent, a dispersing agent, a first initiator, a first chain transfer agent, vinylidene fluoride and a first monomer after removing the oxygen, and carrying out a first polymerization reaction on the vinylidene fluoride and the first monomer under the condition of stirring. The amounts of the first solvent, the first initiator and the first chain transfer agent can be selected according to actual needs, and are not described herein again.
In a preferred embodiment, step (2) may comprise: adding a second solvent, a second chain transfer agent, an emulsifier, an acrylonitrile monomer and a second monomer into the reactor, heating to 40-80 ℃ in an inert atmosphere, and adding a second initiator to perform a second polymerization reaction on the acrylonitrile monomer and the second monomer. The amounts of the second solvent, the second chain transfer agent and the emulsifier can be selected according to actual needs, and are not described herein again.
According to the present disclosure, the conditions of the first polymerization reaction may include: inert atmosphere at 25-100 deg.C and 3-8MPa for 4-8 hr, preferably at 40-60 deg.C and 5-6MPa for 6-7 hr. The conditions of the second polymerization reaction may include: inert atmosphere at 40-80 deg.C and normal pressure for 2-24 hr, preferably 50-70 deg.C for 8-10 hr. The inert atmosphere in the first polymerization reaction and the second polymerization reaction is well known to those skilled in the art, and examples thereof include a nitrogen atmosphere, an argon atmosphere, a helium atmosphere, and the like.
The first and second solvents are conventionally employed by those skilled in the art in light of the present disclosure, for example, the first and second solvents may each be independently selected from at least one of deionized water, N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, and pyridine, preferably deionized water.
The first chain transfer agent and the second chain transfer agent are conventionally employed by those skilled in the art in light of the present disclosure, and for example, the first chain transfer agent and the second chain transfer agent may each be independently selected from one or more of ethyl acetate, butyl acetate, acetone, diethyl carbonate, methyl tert-butyl ether, isopropanol, ethanol, methanol, and dodecanethiol.
The first initiator and the second initiator may be conventionally employed by those skilled in the art in light of the present disclosure, and for example, each of the first initiator and the second initiator is independently selected from one or more of diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-t-butyl peroxide, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, succinyl peroxide, and bis (2-ethylhexyl) peroxydicarbonate.
The dispersing agent is conventionally employed by those skilled in the art in light of the present disclosure, and for example, may be selected from one or more of methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium carboxymethylcellulose, polyvinyl alcohol, sodium polyacrylate, and polyvinylpyrrolidone.
Emulsifiers are well known to those skilled in the art in light of this disclosure, and for example, the emulsifier may be selected from one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium lauryl sulfate, sodium laurate, and sodium polyoxyethylene lauryl sulfate.
The third aspect of the present disclosure provides a lithium ion battery cathode slurry, which includes the cathode binder provided in the first aspect of the present disclosure. The positive electrode binder disclosed by the invention has a good anti-coagulation effect.
According to the present disclosure, the slurry may further include a positive electrode active material, a conductive agent, and a solvent; the content of the positive electrode binder in the slurry is 1 to 5% by weight, preferably 1 to 2% by weight, based on the total weight of solid matter in the slurry.
The method for preparing the positive electrode slurry is well known to those skilled in the art, and for example, the positive electrode slurry can be prepared by dissolving a binder in a solvent and then adding a positive electrode active material and a conductive agent.
According to the present disclosure, the positive active material may include a ternary positive active material LiNi x Co y W z O 2 W is Mn and/or Al, and x + y + z =1,x is 0.8 or more. The conductive agent is well known to those skilled in the art and may be, for example, carbon nanotubes, conductive carbon black; the solvent may also be well known to those skilled in the art, such as N-methylpyrrolidone, N-dimethylformamide, pyridine.
According to the present disclosure, the ratio of the viscosity of the cathode slurry after 48 hours to the viscosity at 0 hours may be 1 to 2, preferably 1 to 1.2. The viscosity of the positive electrode slurry at 0 hour is the viscosity when the binder and other components in the slurry are made into slurry, and the viscosity after 48 hours is the viscosity measured after the slurry is made into slurry, is placed for 48 hours under a dry and closed condition, and is then fully stirred. The positive electrode slurry disclosed by the invention is excellent in stability and has good anti-gelation performance.
The fourth aspect of the present disclosure provides a positive electrode of a lithium ion battery, where the positive electrode of the lithium ion battery includes a current collector and a coating layer covering the current collector, and the coating layer is a positive electrode slurry prepared from the positive electrode slurry provided by the third aspect of the present disclosure. The lithium ion battery positive electrode of the present disclosure may have good flexibility and adhesive strength.
According to the present disclosure, the peel force between the coating and the current collector may be 15-50N/m, preferably 20-35N/m.
A fifth aspect of the present disclosure provides a lithium ion battery including the positive electrode provided by the fourth aspect of the present disclosure.
The present disclosure is further illustrated by the following examples, but is not to be construed as being limited thereby.
The fluorine-containing olefins in the examples and comparative examples were obtained from Sanai Rich corporation, and the other reagents were obtained from Chemicals, inc., national chemical group.
Examples 1 to 10 are preparation examples of the binder, and comparative examples 1 to 6 are preparation comparative examples of the binder.
Example 1
(1) Blowing nitrogen into a closed polymerization reaction kettle to remove oxygen, adding deionized water, diisopropyl peroxydicarbonate (a first initiator), ethyl acetate (a first chain transfer agent), vinylidene fluoride and chlorotrifluoroethylene, mixing and stirring to perform a first polymerization reaction. The reaction pressure is 6MPa, the reaction temperature is 55 ℃, the reaction is finished after 6 hours, and a first component is obtained after filtration, washing and drying;
wherein the weight average molecular weight of the first component is 110 ten thousand, and the content of the vinylidene fluoride is 75 percent by weight based on the total weight of the first component;
(2) Deionized water, lauryl sodium sulfate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and N-hydroxymethyl acrylamide are added into a reaction kettle, the temperature is raised to 70 ℃, ammonium persulfate (second initiator) is added after the temperature is constant, and the second polymerization reaction is carried out under normal pressure. After the reaction is finished for 8 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving;
wherein the weight average molecular weight of the second component is 80 ten thousand, and the content of acrylonitrile is 70 weight percent based on the total weight of the second component;
(3) Mixing the components in a weight ratio of 4:6 to obtain the binder A.
Example 2
A binder was prepared in the same manner as in example 1, except that, in the step (3), the binder was prepared in a weight ratio of 15:5 to obtain a binder B.
Example 3
Binder C was prepared in the same manner as in example 1, except that step (1) was different.
In the step (1), nitrogen is blown into a closed polymerization reaction kettle to remove oxygen, and deionized water, diisopropyl peroxydicarbonate (a first initiator), ethyl acetate (a first chain transfer agent), vinylidene fluoride and tetrafluoroethylene are added and mixed and stirred to carry out a first polymerization reaction. The pressure of the first polymerization reaction is 6MPa, the reaction temperature is 60 ℃, the reaction is finished after 6 hours, and the first component is obtained after filtering, washing and drying; wherein the weight average molecular weight of the first component is 100 ten thousand, and the content of the vinylidene fluoride is 95 weight percent based on the total weight of the first component.
Example 4
Binder D was prepared in the same manner as in example 1, except that step (2) was different.
In the step (2), deionized water, sodium dodecyl benzene sulfonate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and N-hydroxymethyl acrylamide are added into a reaction kettle, the temperature is raised to 75 ℃, and after the temperature is constant, potassium persulfate (second initiator) is added to carry out second polymerization reaction under normal pressure. After the reaction is finished for 7 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving; wherein the weight average molecular weight of the second component is 70 ten thousand, and the content of acrylonitrile is 90 wt% based on the total weight of the second component.
Example 5
Binder E was prepared in the same manner as in example 1, except that step (1) was different.
In the step (1), nitrogen is blown into a closed polymerization reaction kettle to remove oxygen, and deionized water, di-n-propyl peroxydicarbonate (a first initiator), acetone (a first chain transfer agent), vinylidene fluoride and tetrafluoroethylene are added to be mixed and stirred to carry out a first polymerization reaction. The pressure of the first polymerization reaction is 5MPa, the reaction temperature is 50 ℃, the reaction is finished after 6 hours, and the first component is obtained after filtration, washing and drying; wherein the weight average molecular weight of the first component is 50 ten thousand, and the content of the vinylidene fluoride is 80 weight percent based on the total weight of the first component.
Example 6
Binder F was prepared in the same manner as in example 1, except that step (2) was different.
In the step (2), deionized water, sodium dodecyl benzene sulfonate (emulsifier), isopropanol (second chain transfer agent), acrylonitrile and N-hydroxymethyl acrylamide are added into a reaction kettle, the temperature is raised to 75 ℃, and after the temperature is constant, potassium persulfate (second initiator) is added to carry out second polymerization reaction under normal pressure. After the reaction is finished for 9 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving; wherein the weight average molecular weight of the second component is 15 ten thousand, and the content of acrylonitrile is 60% by weight based on the total weight of the second component.
Example 7
(1) Blowing nitrogen into a closed polymerization reaction kettle to remove oxygen, adding N, N-dimethylformamide, deionized water, potassium persulfate (a first initiator), methyl tert-butyl ether (a first chain transfer agent), vinylidene fluoride and chlorotrifluoroethylene, mixing and stirring to perform a first polymerization reaction. The reaction pressure is 4MPa, the reaction temperature is 55 ℃, the reaction is finished after 6 hours, and the first component is obtained after filtration, washing and drying;
wherein the weight average molecular weight of the first component is 100 ten thousand, and the content of the vinylidene fluoride is 85 percent by weight based on the total weight of the first component;
(2) Deionized water, sodium lauryl sulfate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and acrylamide are added into a reaction kettle, the temperature is raised to 70 ℃, ammonium persulfate (second initiator) is added after the temperature is constant, and the second polymerization reaction is carried out under normal pressure. After the reaction is finished for 9 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving;
wherein the weight average molecular weight of the second component is 30 ten thousand, and the content of the acrylonitrile is 70 weight percent based on the total weight of the second component;
(3) Mixing the components in a weight ratio of 1:1 to obtain a binder G.
Example 8
(1) Blowing nitrogen into a closed polymerization reaction kettle to remove oxygen, adding deionized water, diisopropyl peroxydicarbonate (a first initiator), ethyl acetate (a first chain transfer agent), vinylidene fluoride and chlorotrifluoroethylene, mixing and stirring to perform a first polymerization reaction. The reaction pressure is 5MPa, the reaction temperature is 55 ℃, the reaction is finished after 5 hours, and the first component is obtained after filtration, washing and drying;
wherein the weight average molecular weight of the first component is 135 ten thousand, and the content of the vinylidene fluoride is 90 percent by weight based on the total weight of the first component;
(2) Deionized water, sodium dodecyl sulfate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and acrylic acid are added into a reaction kettle, the temperature is raised to 70 ℃, ammonium persulfate (second initiator) is added after the temperature is constant, and the second polymerization reaction is carried out under normal pressure. After the reaction is finished for 10 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving;
wherein the weight average molecular weight of the second component is 90 ten thousand, and the content of acrylonitrile is 50 weight percent based on the total weight of the second component;
(3) Mixing the components in a weight ratio of 3:4 to obtain a binder H.
Example 9
(1) Blowing nitrogen into a closed polymerization reaction kettle to remove oxygen, adding deionized water, diisopropyl peroxydicarbonate (a first initiator), ethyl acetate (a first chain transfer agent), vinylidene fluoride and hexafluoropropylene, mixing and stirring to perform a first polymerization reaction. The reaction pressure is 5MPa, the reaction temperature is 60 ℃, the reaction is finished after 6 hours, and the first component is obtained after filtration, washing and drying;
wherein the weight average molecular weight of the first component is 90 ten thousand, and the content of the vinylidene fluoride is 80 weight percent based on the total weight of the first component;
(2) Deionized water, sodium dodecyl sulfate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and acrylamide are added into a reaction kettle, the temperature is raised to 70 ℃, ammonium persulfate (second initiator) is added after the temperature is constant, and the second polymerization reaction is carried out under normal pressure. After the reaction is finished for 8 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving;
wherein the weight average molecular weight of the second component is 70 ten thousand, and the content of acrylonitrile is 80 weight percent based on the total weight of the second component;
(3) Mixing the following components in percentage by weight: 1 to obtain binder I.
Example 10
(1) Blowing nitrogen into a closed polymerization reaction kettle to remove oxygen, adding deionized water, diisopropyl peroxydicarbonate (a first initiator), ethyl acetate (a first chain transfer agent), vinylidene fluoride and chlorotrifluoroethylene, mixing and stirring to perform a first polymerization reaction. The reaction pressure is 6MPa, the reaction temperature is 45 ℃, the reaction is finished after 5 hours, and the first component is obtained after filtration, washing and drying;
wherein the weight average molecular weight of the first component is 135 ten thousand, and the content of the vinylidene fluoride is 90 percent by weight based on the total weight of the first component;
(2) Deionized water, sodium dodecyl sulfate (emulsifier), dodecyl mercaptan (second chain transfer agent), acrylonitrile and N-hydroxymethyl acrylamide are added into a reaction kettle, the temperature is raised to 70 ℃, ammonium persulfate (second initiator) is added after the temperature is constant, and the second polymerization reaction is carried out under normal pressure. After the reaction is finished for 9 hours, a second component is obtained by precipitation, filtration, washing, drying, crushing and sieving;
wherein the weight average molecular weight of the second component is 50 ten thousand, and the content of acrylonitrile is 65 weight percent based on the total weight of the second component;
(3) Mixing the components in a weight ratio of 3:2 to obtain a binder J.
Comparative example 1
The first component prepared in example 1 was used as binder a.
Comparative example 2
The second component prepared in example 1 was used as binder b.
Comparative example 3
A binder was prepared in the same manner as in example 1, except that, in the step (3), the binder was prepared by mixing 9:1 and the second component to obtain a binder c.
Comparative example 4
A copolymer of acrylic acid and vinylidene fluoride as binder d, the amount of comonomer acrylic acid being 3% by weight.
Comparative example 5
A copolymer of methyl acrylate and acrylonitrile was used as binder e, the comonomer methyl acrylate being used in an amount of 5% by weight.
Comparative example 6
Mixing the binder d in comparative example 4 and the binder e in comparative example 5 in a weight ratio of 5:5, compounding to prepare the binder f.
Examples of preparation of positive electrode slurry and positive electrode sheet
The binders prepared in examples 1 to 10 and comparative examples 1 to 6 were dissolved in NMP (N-methylpyrrolidone), after sufficiently dissolving, the conductive agent super-P was added, stirred for 20min, and then the high nickel ternary material (LiNi) was added 0.8 Co 0.1 Mn 0.1 O 2 ) And continuously stirring for 2h to obtain positive electrode slurry A1-J1 and positive electrode slurry A1-f1. Wherein the content of the positive electrode binder in the slurry is 2 wt%.
Coating the sizing agents A1-J1 and the sizing agents A1-f1 on an aluminum foil, and drying for 30min at 130 ℃ to obtain the positive plate.
Test example
(1) Gel resistance and viscosity test of slurry
The viscosity of the slurry was measured using an Anton Paar MCR 302 rheometer.
(2) Peel force testing of pole pieces
According to the test method of the peeling strength of the adhesive tape GB 2792-2014, the peeling force of the pole piece is tested by adopting a 180-degree peeling test method.
(3) Pole piece flexibility test
A cylindrical shaft bending tester is used, and the specific method comprises the steps of cutting the pole piece into a rectangular sample strip with the width of 5cm, winding the sample strip onto a metal cylinder with the diameter of 2mm, pulling the sample strip at a constant speed of 180 degrees, and observing whether the pole piece is broken or not and cracks. The flexibility of the pole piece is characterized by complete no crack, slight material drop, large material drop and fracture from good to bad. The results of the above tests are shown in Table 1.
TABLE 1
As can be seen from Table 1, comparative examples 4 and 6 gelled and could not be coated; comparative example 5 the viscosity was too low and the slurry was abnormal and could not be applied. The slurry disclosed by the invention is suitable in viscosity and has good anti-gelation performance, and the positive pole piece containing the binder disclosed by the invention has good binding power and flexibility.
The preferred embodiments of the present disclosure have been described in detail above, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.
It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.
In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.
Claims (13)
1. A positive electrode binder, characterized in that the binder comprises a first component and a second component; the first component is a copolymer of vinylidene fluoride and a first monomer, and the first monomer is one or more of C2-C8 olefin and C2-C4 halogenated olefin except vinylidene fluoride; the second component is a copolymer of an acrylonitrile monomer and a second monomer, the acrylonitrile monomer is acrylonitrile and/or methacrylonitrile, and the second monomer is one or more of an acrylamide monomer, an acrylic monomer and a heterocyclic nitrogen monomer; the weight ratio of the first component to the second component is (3:7) - (7:3); the weight average molecular weight of the first component is 80-140 ten thousand, and the weight average molecular weight of the second component is 20-100 ten thousand.
2. The binder of claim 1 wherein the vinylidene fluoride is present in an amount of from 30 to 90 weight percent, based on the total weight of the first component;
the acrylonitrile monomer is present in an amount of 50 to 85 weight percent, based on the total weight of the second component.
3. The binder of claim 1 wherein the C2-C8 olefin comprises one or more of ethylene, propylene, butylene, isobutylene, styrene, and butadiene;
the C2-C4 halogenated olefin comprises one or more of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and 2,3,3,3-tetrafluoropropene;
the acrylamide monomer comprises one or more of methacrylamide, N-hydroxymethyl acrylamide, N-hydroxyethyl acrylamide, N-methacrylamide and N, N-dimethylacrylamide;
the acrylic monomer comprises one or more of methacrylic acid, acrylic acid, crotonic acid and 2-ethyl acrylic acid;
the nitrogen heterocyclic monomer comprises one or more of 2-vinylpyridine, 4-vinylpyridine and N-vinylpyrrolidone.
4. A method of preparing the binder of any one of claims 1 to 3, comprising:
(1) In the presence of a first chain transfer agent, a first initiator and a dispersant, carrying out a first polymerization reaction on vinylidene fluoride and the first monomer in a first solvent, and removing the first solvent to obtain the first component;
(2) In the presence of a second chain transfer agent, a second initiator and an emulsifier, carrying out a second polymerization reaction on an acrylonitrile monomer and the second monomer in a second solvent, and removing the second solvent to obtain a second component;
(3) Mixing the first component and the second component.
5. The method of claim 4, wherein the conditions of the first polymerization reaction comprise: inert atmosphere at 25-100 deg.C and 3-8MPa for 4-8 hr;
the conditions of the second polymerization reaction include: inert atmosphere at 40-80 deg.C and normal pressure for 2-24 hr.
6. The method of claim 4, wherein the first solvent and the second solvent are each independently selected from at least one of deionized water, N-dimethylformamide, N-methylpyrrolidone, tetrahydrofuran, and pyridine;
the first chain transfer agent and the second chain transfer agent are respectively and independently selected from one or more of ethyl acetate, butyl acetate, acetone, diethyl carbonate, methyl tert-butyl ether, isopropanol, ethanol, methanol and dodecyl mercaptan;
the first initiator and the second initiator are respectively and independently selected from one or more of diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-tert-butyl peroxide, potassium persulfate, ammonium persulfate, azobisisobutyronitrile, succinyl peroxide and di (2-ethylhexyl) peroxydicarbonate;
the dispersing agent is selected from one or more of methylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium carboxymethyl cellulose, polyvinyl alcohol, sodium polyacrylate and polyvinylpyrrolidone;
the emulsifier is selected from one or more of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium lauryl sulfate, sodium laurate and polyoxyethylene lauryl sodium sulfate.
7. A positive electrode slurry for a lithium ion battery, characterized by comprising the positive electrode binder according to any one of claims 1 to 3.
8. The positive electrode slurry according to claim 7, further comprising a positive electrode active material, a conductive agent, and a solvent; in the slurry, the content of the positive electrode binder is 1-5 wt% of the total weight of solid matters in the slurry.
9. The positive electrode slurry according to claim 8, wherein the positive electrode active material comprises a ternary positive electrode active material LiNi x Co y W z O 2 W is Mn and/or Al, and x + y + z =1,x is 0.8 or more.
10. The positive electrode slurry according to claim 7, wherein the ratio of the viscosity of the positive electrode slurry after 48 hours to the viscosity at 0 hour is 1 to 2.
11. A positive electrode of a lithium ion battery, comprising a current collector and a coating layer coated on the current collector, wherein the coating layer is prepared from the positive electrode slurry of any one of claims 7 to 10.
12. The positive electrode according to claim 11, wherein a peeling force between the coating layer and the current collector is 15 to 50N/m.
13. A lithium ion battery comprising the lithium ion battery positive electrode according to claim 11 or 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911260132.7A CN112952092B (en) | 2019-12-10 | 2019-12-10 | Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911260132.7A CN112952092B (en) | 2019-12-10 | 2019-12-10 | Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112952092A CN112952092A (en) | 2021-06-11 |
| CN112952092B true CN112952092B (en) | 2022-11-11 |
Family
ID=76225761
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911260132.7A Active CN112952092B (en) | 2019-12-10 | 2019-12-10 | Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112952092B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113488652A (en) * | 2021-06-30 | 2021-10-08 | 昆山兴能能源科技有限公司 | Method for improving agglomeration of lithium ion ternary positive electrode slurry |
| CN114203990A (en) * | 2021-12-02 | 2022-03-18 | 东莞维科电池有限公司 | Positive electrode lithium supplement slurry and preparation method thereof, positive plate and lithium ion battery |
| CN114976003B (en) * | 2022-05-11 | 2024-04-23 | 蜂巢能源科技(马鞍山)有限公司 | Fluorine-free binder and preparation method and application thereof |
| WO2024011371A1 (en) * | 2022-07-11 | 2024-01-18 | 宁德时代新能源科技股份有限公司 | Binder for positive electrode plate and synthesis method therefor, positive electrode plate comprising same, secondary battery and electric device |
| CN118056292A (en) * | 2022-07-22 | 2024-05-17 | 宁德时代新能源科技股份有限公司 | Modified binder, binder composition, preparation method, negative electrode slurry, negative electrode plate, secondary battery, battery module, battery pack and power utilization device |
| CN117638070A (en) * | 2022-08-30 | 2024-03-01 | 宁德时代新能源科技股份有限公司 | Positive electrode slurry, preparation method, secondary battery and electricity utilization device |
| CN117777904B (en) * | 2024-02-27 | 2024-05-28 | 湖南高瑞电源材料有限公司 | Positive electrode fluorine-free binder material, and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212053A (en) * | 2006-12-31 | 2008-07-02 | 上海比亚迪有限公司 | Positive pole of Li-ion battery and the Li-ion battery |
| CN101651211A (en) * | 2008-08-11 | 2010-02-17 | 比亚迪股份有限公司 | Anode material composition, and anode and battery comprising same |
| CN104497190A (en) * | 2014-12-29 | 2015-04-08 | 浙江孚诺林化工新材料有限公司 | Preparation method of vinylidene fluoride polymer of lithium ion battery electrode material binder |
| CN106220779A (en) * | 2016-08-17 | 2016-12-14 | 四川茵地乐科技有限公司 | Acrylonitrile copolymer binder and the application in lithium ion battery thereof |
| CN106410188A (en) * | 2016-12-06 | 2017-02-15 | 先进储能材料国家工程研究中心有限责任公司 | Lithium ion battery positive electrode slurry and preparation method thereof |
-
2019
- 2019-12-10 CN CN201911260132.7A patent/CN112952092B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101212053A (en) * | 2006-12-31 | 2008-07-02 | 上海比亚迪有限公司 | Positive pole of Li-ion battery and the Li-ion battery |
| CN101651211A (en) * | 2008-08-11 | 2010-02-17 | 比亚迪股份有限公司 | Anode material composition, and anode and battery comprising same |
| CN104497190A (en) * | 2014-12-29 | 2015-04-08 | 浙江孚诺林化工新材料有限公司 | Preparation method of vinylidene fluoride polymer of lithium ion battery electrode material binder |
| CN106220779A (en) * | 2016-08-17 | 2016-12-14 | 四川茵地乐科技有限公司 | Acrylonitrile copolymer binder and the application in lithium ion battery thereof |
| CN106410188A (en) * | 2016-12-06 | 2017-02-15 | 先进储能材料国家工程研究中心有限责任公司 | Lithium ion battery positive electrode slurry and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112952092A (en) | 2021-06-11 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112952092B (en) | Positive electrode binder and preparation method thereof, positive electrode slurry, positive electrode and lithium ion battery | |
| JP6758505B2 (en) | Its application in acrylonitrile copolymer binders and lithium-ion batteries | |
| CN111139002B (en) | Water-soluble adhesive for lithium ion battery, preparation method of water-soluble adhesive, electrode plate and battery | |
| EP2660908B1 (en) | Electrode binder composition for nonaqueous electrolyte battery, electrode for nonaqueous electrolyte battery, and nonaqueous electrolyte battery | |
| JP5002052B2 (en) | Aqueous adhesive for lithium ion battery, method for producing the same, and lithium ion battery positive electrode sheet | |
| KR100743451B1 (en) | Binder composition for electrodes of lithium ion secondary batteries and use thereof | |
| EP3493304B1 (en) | Conductive resin composition for electrodes, electrode composition, electrode using same and lithium ion battery | |
| WO2017077940A1 (en) | Binder for negative electrodes of lithium ion secondary batteries, slurry composition for negative electrodes, negative electrode, and lithium ion secondary battery | |
| JP2016042408A (en) | Manufacturing method of lithium secondary battery electrode binder, and lithium secondary battery electrode binder | |
| WO2015099021A1 (en) | Binder composition for electrode of lithium ion secondary cell, electrode of lithium ion secondary cell, and lithium ion secondary cell | |
| JP4412443B2 (en) | Thickener for lithium ion secondary battery negative electrode and lithium ion secondary battery | |
| JP2016066601A (en) | Binder composition for lithium ion secondary battery electrode, lithium ion secondary battery electrode, and lithium ion secondary battery | |
| JP7062476B2 (en) | Binder composition, electrode mixture raw material, electrode mixture, electrode, non-aqueous electrolyte secondary battery and method for manufacturing electrode mixture | |
| CN116891548A (en) | Post-crosslinking aqueous adhesive special for lithium battery and preparation method and application thereof | |
| JP4240604B2 (en) | Binder composition, slurry for battery electrode, electrode and battery | |
| JP2011165456A (en) | Copolymer, binder resin composition for battery electrode, and battery electrode | |
| JP3815521B2 (en) | Binder composition for battery, slurry for battery electrode, electrode and battery | |
| JPH10279608A (en) | Polymer, battery binder made therefrom, electrode and lithium secondary battery | |
| JPH11297313A (en) | Slurry for secondary battery electrode, electrode for battery, and secondary battery | |
| JPH11297329A (en) | Binder composition for secondary battery electrode, preparation thereof, slurry for battery electrode, electrode for battery, and the secondary | |
| EP4024534A1 (en) | Binder composition for electricity storage devices, slurry for electricity storage device electrodes, electricity storage device electrode, and electricity storage device | |
| CN111916740A (en) | Polyunsaturated carboxylic group controllable crosslinking type binder and lithium ion battery containing same | |
| JP6356164B2 (en) | Conductive paste for lithium ion battery positive electrode and composite paste for lithium ion battery positive electrode | |
| CN116200150B (en) | Positive electrode binder of lithium ion battery and preparation method and application thereof | |
| JPH10270047A (en) | Battery binder composition, battery electrode slurry, lithyum secondary battery electrode, lithyum secondary battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |