CN116314805A - Negative electrode material binder of lithium ion battery - Google Patents
Negative electrode material binder of lithium ion battery Download PDFInfo
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- CN116314805A CN116314805A CN202310249919.3A CN202310249919A CN116314805A CN 116314805 A CN116314805 A CN 116314805A CN 202310249919 A CN202310249919 A CN 202310249919A CN 116314805 A CN116314805 A CN 116314805A
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/52—Amides or imides
- C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
- C08F220/56—Acrylamide; Methacrylamide
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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
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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
- 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
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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
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- 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
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Abstract
The application relates to the technical field of adhesives, and particularly provides a lithium ion battery negative electrode material adhesive which is formed by mixing a VAE emulsion and a polyacrylic acid derivative emulsion according to a weight ratio of 40:1-1:1; the polyacrylic acid derivative emulsion is obtained by the polymerization reaction of hydrophilic acrylic acid monomers and hydrophobic acrylic acid monomers in a water phase system according to the weight ratio of 3:7-9:1. The adhesive for the lithium ion battery cathode material has the flexibility of VAE and the dispersibility and the adhesiveness of polyacrylic acid derivatives, is used as the adhesive for the lithium ion battery cathode material together, and has good dispersibility, adhesiveness and flexibility; the obtained button cell assembled by the negative electrode plate has higher coulomb efficiency and lower alternating current impedance.
Description
Technical Field
The application relates to the technical field of binders, in particular to a lithium ion battery negative electrode material binder.
Background
The negative electrode material of the lithium ion battery is mainly a graphite material, and because the surface shape of the graphite material is complex and difficult to disperse, the high requirement is put forward on the binder, so that the wet dispersibility of the graphite material is required to be good, the adhesion to a current collector is required to be good, the flexibility is required to be good, and the cracking, the cracking or the falling of the electrode during the curling is avoided.
Thus, the properties of the binder have a significant impact on the performance of the lithium ion battery.
Disclosure of Invention
In order to solve the technical problems, the application provides a preparation method of a lithium ion battery negative electrode material binder and the lithium ion battery negative electrode material binder.
The application adopts the following technical scheme:
a lithium ion battery negative electrode material binder is prepared by mixing VAE emulsion and polyacrylic acid derivative emulsion according to a weight ratio of 40:1-1:10;
the acrylic acid derivative emulsion is obtained by polymerization reaction of hydrophilic acrylic acid monomers and hydrophobic acrylic acid monomers in a water phase system according to the weight ratio of 3:7-9:1.
Preferably, the solid content of the binder of the anode material of the lithium ion battery is 10-50%.
Preferably, the VAE emulsion has a solids content of 40-70%.
Preferably, the weight ratio of the VAE emulsion to the acrylic acid derivative emulsion is 10:1-1:10.
Preferably, the hydrophilic acrylic monomer has the chemical formula CH 2 ＝CR 1 R 2 Wherein R is 1 Selected from H or C1-C4 alkyl, R 2 Selected from-CONH 2 、-CONHCH 3 、-CONHCH 2 CH 3 、-CON(CH 3 ) 2 、-CON(CH 2 CH 3 ) 2 、-CONHCH 2 OH、-CONHCH 2 CH 2 OH、-COOCH 2 CH 2 OH、-COOCH 2 CH 2 CH 2 OH、-COOCH 2 CHCH 3 OH、-COOCH 2 CH 2 CH 2 CH 2 OH、-COO(CH 2 CH 2 O) a H and-COO (CH) 2 ) b PO 3 H, and/or contains-COOH, -COOM, - (C) 6 H 5 )COOM、-SO 3 M and- (C) 6 H 5 )SO 3 One or more of the organic structures of the M functional group, a=1-40, b=1-12, M is selected from Li + 、Na + And K + One or more of them.
Preferably, the hydrophobic olefinic monomer has the chemical formula CH 2 ＝CR 3 R 4 Wherein R is 3 Selected from H or C1-C4 alkyl, R 4 Selected from-COOC n H 2n+1 and-C m H 2m One or more of CN, n=1-40, m=0-6.
Preferably, the weight ratio of the hydrophilic acrylic monomer to the hydrophobic acrylic monomer is 5:5 to 9:1.
Preferably, the polymerization reaction is: the hydrophilic acrylic monomer and the hydrophobic acrylic monomer are added into a reaction system together to carry out polymerization reaction.
Preferably, the polymerization reaction is: the hydrophilic acrylic monomer is added into a reaction system to carry out polymerization reaction, and then the hydrophobic acrylic monomer is added to carry out polymerization reaction.
Preferably, the polymerization reaction is: firstly, adding 30-70% by weight of the hydrophilic acrylic monomer for polymerization, then adding 20-80% by weight of the hydrophobic acrylic monomer for polymerization, then adding the rest of the hydrophilic acrylic monomer for polymerization, and then adding the rest of the hydrophobic acrylic monomer.
In summary, the present application has the following beneficial effects:
the VAE emulsion and the polyacrylic acid derivative emulsion with the hydrophilic and hydrophobic properties are adopted to blend, the VAE emulsion has the flexibility of the VAE, the dispersibility and the adhesiveness of the polyacrylic acid derivative, and the obtained adhesive is suitable for being used as an adhesive of a lithium ion battery anode material, and has good dispersibility, adhesiveness and flexibility.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below.
Throughout the specification, unless specifically indicated otherwise, the terms used herein should be understood as meaning as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification will control.
The application provides a lithium ion battery negative electrode material binder which is formed by mixing VAE emulsion and polyacrylic acid derivative emulsion according to a weight ratio of 40:1-1:10;
the polyacrylic acid derivative emulsion is obtained by the polymerization reaction of hydrophilic acrylic acid monomers and hydrophobic acrylic acid monomers in a water phase system according to the weight ratio of 3:7-9:1.
The VAE emulsion is emulsion of vinyl acetate/ethylene copolymer, has good flexibility after the VAE emulsion is formed into a film, and combines the high dispersibility and the adhesive force of the polyacrylic acid derivative emulsion.
In a preferred embodiment of the present application, the solid content of the binder of the negative electrode material of the lithium ion battery is 10-50%. The book is provided withIn the application, the solid content testing method comprises the following steps: accurately weighing the adhesive sample in an open weighing bottle, putting the adhesive sample in a baking oven at 120 ℃ for baking for 2 hours, taking out the adhesive sample, transferring the adhesive sample into a dryer for cooling, and weighing the weighing bottle again. Solid content= (W) 2 -W 1 )/W 0 ×100％，W 0 To the initial weight of the adhesive sample, W 1 To weigh the net weight of the bottle, W 2 The bottles were weighed after baking.
In a preferred embodiment of the present application, the VAE emulsion has a solids content of 40-70%. The VAE emulsion generally contains protective colloid such as polyvinyl alcohol and/or surfactant, can also play a role in dispersing the obtained adhesive, and has better stability by combining the hydrophilic and hydrophobic properties of the polyacrylic acid derivative chain segments.
In a preferred embodiment of the present application, the weight ratio of the VAE emulsion to the polyacrylic acid derivative emulsion is from 10:1 to 1:10. The weight ratio of the VAE emulsion to the polyacrylic acid derivative emulsion is in the range, and the comprehensive performance of the adhesive is better. For example, the weight ratio may be 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, and the like.
In a preferred embodiment of the present application, the hydrophilic acrylic monomer has the chemical formula CH 2 ＝CR 1 R 2 Wherein R is 1 Selected from H or C1-C4 alkyl, R 2 Selected from-CONH 2 、-CONHCH 3 、-CONHCH 2 CH 3 、-CON(CH 3 ) 2 、-CON(CH 2 CH 3 ) 2 、-CONHCH 2 OH、-CONHCH 2 CH 2 OH、-COOCH 2 CH 2 OH、-COOCH 2 CH 2 CH 2 OH、-COOCH 2 CHCH 3 OH、-COOCH 2 CH 2 CH 2 CH 2 OH、-COO(CH 2 CH 2 O) a H and-COO (CH) 2 ) b PO 3 H, and/or contains-COOH, -COOM, - (C) 6 H 5 )COOM、-SO 3 M and- (C) 6 H 5 )SO 3 In the organic structure of M functional groupsA=1 to 40, b=1 to 12, and m is selected from Li + 、Na + And K + One or more of them. For example, hydrophilic acrylic monomers are acrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, N-methylacrylamide, N-dimethylacrylamide, acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, sodium acrylate sulfonate, polyethylene glycol acrylate, and the like.
In a preferred embodiment of the present application, the hydrophobic olefinic acid monomer has the chemical formula CH 2 ＝CR 3 R 4 Wherein R is 3 Selected from H or C1-C4 alkyl, R 4 Selected from-COOC n H 2n+1 and-C m H 2m One or more of CN, n=1-40, m=0-6. For example, the hydrophobic acrylic monomer may be methyl methacrylate, butyl acrylate, ethyl acrylate, acrylonitrile, octyl acrylate, isooctyl acrylate, 3-butenenitrile, and the like.
In a preferred embodiment of the present application, the weight ratio of hydrophilic acrylic monomer to hydrophobic acrylic monomer is from 5:5 to 9:1. Because the VAE is a relatively hydrophobic polymer, the hydrophilic and hydrophobic acrylic monomers are regulated, so that the adhesive has balanced hydrophilic and hydrophobic properties, and the adhesive has good comprehensive performance.
In a preferred embodiment of the present application, the polymerization reaction is: the hydrophilic acrylic monomer and the hydrophobic acrylic monomer are added into a reaction system together for polymerization reaction. The hydrophilic acrylic monomer and the hydrophobic acrylic monomer are added into a reaction system together for polymerization reaction, and the polymer in the obtained polyacrylic acid derivative emulsion is a random copolymer.
In a preferred embodiment of the present application, the polymerization reaction is: firstly, hydrophilic acrylic monomers are added into a reaction system to carry out polymerization reaction, and then hydrophobic acrylic monomers are added into the reaction system to carry out polymerization reaction. Firstly adding hydrophilic acrylic monomers into a reaction system for polymerization reaction, then adding hydrophobic acrylic monomers for polymerization reaction, firstly preparing hydrophilic acrylic derivative chain segments, and then grafting hydrophobic acrylic derivative chain segments to obtain the hydrophilic-hydrophobic block copolymer.
In a preferred embodiment of the present application, the polymerization reaction is: firstly, adding 30-70% of hydrophilic acrylic monomers by weight for polymerization, then adding 20-80% of hydrophobic acrylic monomers by weight for polymerization, then adding the rest of hydrophilic acrylic monomers for polymerization, and then adding the rest of hydrophobic acrylic monomers. Adding a part of hydrophilic acrylic monomer and a proper amount of initiator, performing polymerization reaction to form a hydrophilic chain segment, adding a part of hydrophobic acrylic monomer and a proper amount of initiator, grafting the hydrophilic chain segment to the hydrophobic chain segment, adding the rest of hydrophilic acrylic monomer and a proper amount of initiator, continuously grafting the hydrophilic chain segment, finally adding the rest of hydrophobic acrylic monomer, continuously grafting the hydrophobic chain segment, and forming a multi-block copolymer structure similar to the hydrophilic chain segment, the hydrophobic chain segment, the hydrophilic chain segment and the hydrophobic chain segment, wherein after being mixed with a VAE emulsion, the dispersion of the anode material is better.
The technical scheme of the application is described in detail below with reference to examples and comparative examples. Unless otherwise indicated, the parts in the examples and comparative examples below are parts by weight.
Preparation example 1
15 parts of acrylamide, 5 parts of hydroxyethyl acrylate, 8 parts of butyl acrylate, 12 parts of methyl acrylate and 130 parts of water are added into a reaction vessel, the temperature is raised to 65 ℃, 4 parts of ammonium persulfate solution with the concentration of 10wt% is dropwise added, the temperature of the reaction system is maintained at 70+/-2 ℃, the ammonium persulfate solution is dropwise added after 3 hours, the constant-temperature reaction is continued for 2 hours, the temperature is reduced to below 40 ℃, the pH is regulated to 6.0-6.5, and the solid content is regulated to 20+/-1% by adding water, so that the polyacrylic acid derivative emulsion is obtained.
Preparation example 2
Adding 20 parts of acrylamide, 8 parts of acrylic acid, 6 parts of butyl acrylate, 6 parts of acrylonitrile and 180 parts of water into a reaction vessel, heating to 65 ℃, dropwise adding 4 parts of ammonium persulfate solution with the concentration of 10wt%, maintaining the temperature of a reaction system at 70+/-2 ℃, dropwise adding the ammonium persulfate solution for 3 hours, continuously keeping the constant temperature for reaction for 3 hours, cooling to below 40 ℃, adjusting the pH to 6.0-6.5, and adding water to adjust the solid content to 15+/-1%, thereby obtaining the polyacrylic acid derivative emulsion.
Preparation example 3
Adding 20 parts of acrylamide, 8 parts of acrylic acid, 6 parts of hydroxyethyl acrylate, 3 parts of butyl acrylate, 3 parts of acrylonitrile and 200 parts of water into a reaction container, heating to 65 ℃, dropwise adding 4 parts of ammonium persulfate solution with the concentration of 10wt%, maintaining the temperature of a reaction system at 70+/-2 ℃, dropwise adding the ammonium persulfate solution for 3 hours, continuously carrying out constant-temperature reaction for 3 hours, cooling to below 40 ℃, adjusting the pH to 6.0-6.5, and adding water to adjust the solid content to 15+/-1%, thereby obtaining the polyacrylic acid derivative emulsion.
Preparation example 4
Adding 20 parts of acrylamide, 8 parts of acrylic acid and 100 parts of water into a reaction vessel, heating to 65 ℃, dropwise adding 3 parts of ammonium persulfate solution with the concentration of 10wt%, maintaining the temperature of a reaction system at 70+/-2 ℃, dropwise adding the ammonium persulfate solution for 2 hours, continuously performing constant-temperature reaction for 3 hours, adding 6 parts of butyl acrylate and 6 parts of acrylonitrile, dropwise adding 1 part of ammonium persulfate solution with the concentration of 10wt%, dropwise adding the ammonium persulfate solution for 2 hours, continuously performing constant-temperature reaction for 3 hours, cooling to below 40 ℃, adjusting the pH to 6.0-6.5, and adding water to adjust the solid content to 25+/-1%, thereby obtaining the polyacrylic acid derivative emulsion.
Preparation example 5
20 parts of acrylamide and 8 parts of acrylic acid are mixed to form a hydrophilic monomer, and 6 parts of butyl acrylate and 6 parts of acrylonitrile are mixed to form a hydrophobic monomer.
14 parts of hydrophilic monomer and 100 parts of water are added into a reaction vessel, the temperature is raised to 65 ℃,2 parts of ammonium persulfate solution with the concentration of 10wt% is dripped, the temperature of a reaction system is maintained to be 70+/-2 ℃, the constant temperature reaction is continued for 3 hours, 6 parts of hydrophobic monomer are added, 1 part of ammonium persulfate solution with the concentration of 10wt% is dripped, the constant temperature reaction is continued for 3 hours, the rest 14 parts of hydrophilic monomer are added, 0.5 part of ammonium persulfate solution with the concentration of 10wt% is dripped, the constant temperature reaction is continued for 4 hours, the rest 6 parts of hydrophobic monomer are added, 0.5 part of ammonium persulfate solution with the concentration of 10wt% is dripped, the constant temperature reaction is continued for 5 hours, the temperature is reduced to be below 40 ℃, the pH is regulated to be 6.0-6.5, and the solid content is regulated to be 25+/-1% by adding water, so as to obtain the polyacrylic acid derivative emulsion.
The VAE emulsions in examples 1-5 below were derived from Dalian chemistry DA-102, and the VAE emulsions in examples 6-10 and comparative examples 1-4 were derived from broad-spectrum chemical GW-706.
Example 1
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 1 were mixed at a weight ratio of 10:1, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 2
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 2 were mixed at a weight ratio of 3:1, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 3
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 3 were mixed in a weight ratio of 1:1, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 4
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 4 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 5
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 5 were mixed in a weight ratio of 1:5, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 6
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 1 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 7
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 2 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 8
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 3 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 9
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 4 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Example 10
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 5 were mixed in a weight ratio of 1:3, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Comparative example 1
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 2 were mixed at a weight ratio of 45:1, and water was added to adjust the solid content to 20.+ -. 1%, thereby obtaining an adhesive.
Comparative example 2
The VAE emulsion and the polyacrylic acid derivative emulsion of preparation example 2 were mixed in a weight ratio of 1:15, and water was added to adjust the solid content to 15.+ -. 1%, thereby obtaining an adhesive.
Comparative example 3
The adhesive is polyacrylic acid derivative emulsion of preparation example 2, and water is added to adjust the solid content to 15+/-1%.
Comparative example 4
In preparation example 2, acrylamide was adjusted from 20 parts to 5.7 parts, acrylic acid was adjusted from 8 parts to 2.3 parts, butyl acrylate was adjusted from 6 parts to 16 parts, acrylonitrile was adjusted from 6 parts to 16 parts, and the remaining steps were kept unchanged. The acrylic acid derivative emulsion was unstable and precipitated after 2 days of standing.
Preparation of negative electrode slurry and pole piece
(1) Mixing the binder to be tested and 50% of water, dispersing for 12 minutes at a rotating speed of 3m/s, adding SP conductive carbon black, stirring for 10 minutes at a rotating speed of 0.5m/s, and stirring for 120 minutes at a high speed of 6 m/s; the rotation speed was adjusted down to 1m/s, 50% of the negative electrode material (fir FSN-1) was added, dispersed for 20 minutes, and then the remaining 50% of the negative electrode material and the remaining 50% of the water were added for 30 minutes, followed by stirring at a high speed of 6m/s for 120 minutes. After the dispersion is finished, the viscosity is regulated to be between 2000 and 3500 mPa.s, and a 150-mesh filter screen is used for filtering to finish discharging. Placing copper foil on a coater, adjusting the scale of a scraper of a wet film preparation device, uniformly pouring the filtered slurry, sending into 100 ℃ environment, blowing and baking until the slurry is dried, and cutting the slurry into a specification of 12.5cm multiplied by 5cm and single-sided surface densityAt 100-110g/m 2 Is a pole piece.
Pole piece peel force test: and (5) sending the cut pole piece into a 35% RH thermostatic chamber for 30 minutes. The coating layer faces outwards, the copper foil faces inwards to attach the two pole pieces, and the pole pieces are sent into an electric roller press to be rolled to 1.6g/cm 3 After rolling, placing for 30 minutes, selecting five stainless steel plates with the specification of 12.5cm multiplied by 5cm, attaching double-sided adhesive tapes with corresponding specifications on the stainless steel plates, attaching a pole piece on the double-sided adhesive tapes in a way that a coating faces downwards, attaching a piece of masking paper tape with the width of 2.5cm on a copper foil, and testing the stripping force of the pole piece by an electronic stripping machine after the pole piece steel plates are rolled back and forth for one circle by an electronic rolling roller with a certain pressure (1 kg).
Pole piece flexibility test: the test was performed using a model ITM-RRD01 softness tester.
And (3) testing swelling rate of the adhesive film electrolyte: the adhesive to be tested forms a film with an average thickness of 100+/-10 mu m. Cutting the adhesive film to obtain 1×4cm test piece, placing into 105 deg.C air drying oven, oven drying for 4 hr, taking out weighing record M 1 Soaking in a vial containing electrolyte (1M LiPF6 in EC:DMC:EMC =1:1:1) at constant temperature for 48 hr, taking out, wiping the electrolyte on the surface of the test piece with filter paper, and weighing M 2 The swelling ratio of the adhesive film is (M 2 -M 1 )/M 1 ×100％。
The results are shown in Table 1.
TABLE 1
| Stripping force (N/5 cm) | Softness (mN) | Swelling ratio of electrolyte (%) | |
| Example 1 | 1.87 | 98 | 20.2 |
| Example 2 | 2.27 | 107 | 18.4 |
| Example 3 | 2.40 | 125 | 16.7 |
| Example 4 | 2.65 | 132 | 14.8 |
| Example 5 | 2.78 | 140 | 13.7 |
| Example 6 | 2.51 | 127 | 14.5 |
| Example 7 | 2.57 | 130 | 14.1 |
| Example 8 | 2.60 | 134 | 13.3 |
| Example 9 | 2.62 | 127 | 14.8 |
| Example 10 | 2.65 | 125 | 14.6 |
| Comparative example 1 | 1.41 | 94 | 980.4 |
| Comparative example 2 | 2.78 | 178 | 8.9 |
| Comparative example 3 | 2.81 | 189 | 4.3 |
As can be seen from the data in table 1, the binder for the negative electrode material of the lithium ion battery is used for dispersing and bonding the negative electrode material, has better stripping force, softness and electrolyte swelling rate, and has better performance than the acrylic acid derivative emulsion with a random structure.
Battery button assembly process
The assembly sequence is from bottom to top negative electrode shell, elastic sheet, gasket, lithium sheet, electrolyte, diaphragm, electrolyte, electrode sheet and positive electrode shell; the battery fittings were assembled in sequence and sealed under 1000kg pressure.
Electrolyte composition: 1M LiPF6 in EC:DMC:EMC =1:1:1.
A diaphragm: celgard 2325.
Lithium sheet: kolu 15.0X1.0 mm.
The first coulombic efficiency and impedance data are shown in table 2.
TABLE 2
| First coulombic efficiency/% | Ac impedance/Ω | |
| Example 1 | 92.3 | 37.6 |
| Example 2 | 93.5 | 35.9 |
| Example 3 | 94.1 | 34.2 |
| Example 4 | 94.4 | 32.6 |
| Example 5 | 94.8 | 36.7 |
| Example 6 | 94.2 | 34.7 |
| Example 7 | 94.6 | 34.6 |
| Example 8 | 94.1 | 33.9 |
| Example 9 | 94.9 | 34.1 |
| Example 10 | 95.0 | 33.3 |
| Comparative example 1 | 77.9 | 89.3 |
| Comparative example 2 | 95.2 | 53.7 |
| Comparative example 3 | 95.5 | 58.5 |
As can be seen from the data in table 2, the negative electrode material prepared by the binder prepared by the application is used for a lithium ion battery, and the lithium ion battery has the characteristics of high initial coulomb efficiency and low alternating current impedance due to the characteristics of dispersion, high adhesion, flexibility and the like.
The present embodiment is merely illustrative of the present application and is not intended to be limiting, and those skilled in the art, after having read the present specification, may make modifications to the present embodiment without creative contribution as required, but is protected by patent laws within the scope of the claims of the present application.
Claims (10)
1. The lithium ion battery negative electrode material binder is characterized by being prepared by mixing VAE emulsion and polyacrylic acid derivative emulsion according to a weight ratio of 40:1-1:10;
the acrylic acid derivative emulsion is obtained by polymerization reaction of hydrophilic acrylic acid monomers and hydrophobic acrylic acid monomers in a water phase system according to the weight ratio of 3:7-9:1.
2. The lithium ion battery anode material binder of claim 1, wherein the solid content of the lithium ion battery anode material binder is 10-50%.
3. The lithium ion battery anode material binder of claim 1, wherein the VAE emulsion has a solids content of 40-70%.
4. The lithium ion battery anode material binder of claim 1, wherein the weight ratio of the VAE emulsion to the acrylic acid derivative emulsion is 10:1 to 1:10.
5. The lithium ion battery anode material binder of claim 1, wherein the hydrophilic acrylic monomer has a chemical formula of CH 2 =CR 1 R 2 Wherein R is 1 Selected from H or C1-C4 alkyl, R 2 Selected from-CONH 2 、-CONHCH 3 、-CONHCH 2 CH 3 、-CON(CH 3 ) 2 、-CON(CH 2 CH 3 ) 2 、-CONHCH 2 OH、-CONHCH 2 CH 2 OH、-COOCH 2 CH 2 OH、-COOCH 2 CH 2 CH 2 OH、-COOCH 2 CHCH 3 OH、-COOCH 2 CH 2 CH 2 CH 2 OH、-COO(CH 2 CH 2 O) a H and-COO (CH) 2 ) b PO 3 H, and/or contains-COOH, -COOM, - (C) 6 H 5 )COOM、-SO 3 M and- (C) 6 H 5 )SO 3 One or more of the organic structures of the M functional group, a=1-40, b=1-12, M is selected from Li + 、Na + And K + One or more of them.
6. The lithium ion battery anode material binder of claim 1, wherein the hydrophobic acrylic monomer has a chemical formula of CH 2 =CR 3 R 4 Wherein R is 3 Selected from H or C1-C4 alkyl, R 4 Selected from-COOC n H 2n+1 and-C m H 2m One or more of CN, n=1-40, m=0-6.
7. The lithium ion battery anode material binder of claim 1, wherein the weight ratio of the hydrophilic acrylic monomer to the hydrophobic acrylic monomer is 5:5-9:1.
8. The lithium ion battery anode material binder of claim 1, wherein the polymerization reaction is: the hydrophilic acrylic monomer and the hydrophobic acrylic monomer are added into a reaction system together to carry out polymerization reaction.
9. The lithium ion battery anode material binder of claim 1, wherein the polymerization reaction is: the hydrophilic acrylic monomer is added into a reaction system to carry out polymerization reaction, and then the hydrophobic acrylic monomer is added to carry out polymerization reaction.
10. The lithium ion battery anode material binder of claim 1, wherein the polymerization reaction is: firstly, adding 30-70% by weight of the hydrophilic acrylic monomer for polymerization, then adding 20-80% by weight of the hydrophobic acrylic monomer for polymerization, then adding the rest of the hydrophilic acrylic monomer for polymerization, and then adding the rest of the hydrophobic acrylic monomer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310249919.3A CN116314805A (en) | 2023-03-15 | 2023-03-15 | Negative electrode material binder of lithium ion battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310249919.3A CN116314805A (en) | 2023-03-15 | 2023-03-15 | Negative electrode material binder of lithium ion battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116314805A true CN116314805A (en) | 2023-06-23 |
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| CN202310249919.3A Pending CN116314805A (en) | 2023-03-15 | 2023-03-15 | Negative electrode material binder of lithium ion battery |
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| CN (1) | CN116314805A (en) |
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- 2023-03-15 CN CN202310249919.3A patent/CN116314805A/en active Pending
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