CN117820985A - Aqueous polymer-based binder and negative electrode - Google Patents

Aqueous polymer-based binder and negative electrode Download PDF

Info

Publication number
CN117820985A
CN117820985A CN202410036117.9A CN202410036117A CN117820985A CN 117820985 A CN117820985 A CN 117820985A CN 202410036117 A CN202410036117 A CN 202410036117A CN 117820985 A CN117820985 A CN 117820985A
Authority
CN
China
Prior art keywords
polymer
parts
emulsion
mass
stirring
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.)
Pending
Application number
CN202410036117.9A
Other languages
Chinese (zh)
Inventor
吴朝森
李伟
刘志滨
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huizhou Pusaida New Material Co ltd
Original Assignee
Huizhou Pusaida New Material Co ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Huizhou Pusaida New Material Co ltd filed Critical Huizhou Pusaida New Material Co ltd
Priority to CN202410036117.9A priority Critical patent/CN117820985A/en
Publication of CN117820985A publication Critical patent/CN117820985A/en
Pending legal-status Critical Current

Links

Landscapes

  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

The invention provides a water-based polymer binder which is characterized by comprising, by mass, 35-45 parts of a polymer I, 25-40 parts of a polymer II, 10-25 parts of a polymer III, 1-5 parts of a colloid stabilizer, 0.2-2 parts of a pH regulator and water. The invention also provides a negative electrode. The aqueous polymer-based binder of the present invention includes a polymer I, a polymer II and a polymer III. The polymer I serves as a soft chain structure in the invention, and also has the function of improving the flexibility of the binder and enabling the system to have better extensibility. The polymer II is a polymer hard chain structure, can improve the cohesive force and mechanical strength of the system, plays a role in inhibiting the rebound of the pole piece, improves the bonding strength, and has excellent chemical stability. The polymer III improves the adhesive force to the current collector by introducing polar groups.

Description

Aqueous polymer-based binder and negative electrode
Technical Field
The invention relates to the technical field of high polymer materials, in particular to a high polymer material technology of lithium battery energy storage equipment, and more particularly relates to a water-based polymer-based binder and a negative electrode using the water-based polymer-based binder.
Background
In recent years, along with development of technology, lithium batteries are increasingly widely applied in life of people by virtue of the outstanding advantages of high voltage, high energy density, good cycle performance, low self discharge and the like, and lithium ion batteries in various industries such as electric automobiles, mobile phones, notebook computers, aerospace and the like are widely seen. As the lithium battery cathode at the low potential end of the lithium battery, the cost and the performance of the cathode material play a vital role in lithium battery equipment. The lithium ion battery mainly comprises a positive electrode, a negative electrode, a diaphragm and electrolyte. When the battery is connected through an external circuit, chemical reactions are performed on the electrodes due to the difference of lithium chemical potentials of the positive electrode and the negative electrode, and electrons form current through the external circuit along with the transfer process of lithium ions inside the battery.
The lithium ion battery is composed of five parts: the battery comprises a battery shell, a positive pole piece, a diaphragm, a negative pole piece and electrolyte. The binder plays a role in constructing a high-efficiency, uniform and stable conductive/ion transmission network in the anode material, and the existence of the binder ensures good electrical contact and uniform current density of the pole piece on a microscopic scale, so that oxidation-reduction reaction can be normally carried out. The traditional CMC or SBR adhesive has single function, and the typical traditional SBR adhesive is mainly prepared by polymerizing butadiene-styrene-acrylic acid through low-temperature emulsion, has a simple soft and hard monomer copolymerization structure and residual-C=C-unsaturated double bonds in a polymerization chain, so that the adhesive has obvious ageing resistance and oxidation resistance, and has obvious reduction in swelling performance and adhesion effect on a current collector after repeated cycle electrical property test of a battery pole piece, thereby seriously influencing the cycle service life of a lithium battery.
Disclosure of Invention
In view of the above, the invention provides a water-based polymer binder and a negative electrode, which are used for solving the problems of poor aging resistance, poor oxidation resistance, short battery cycle service life and the like of the existing water-based polymer binder.
In a first aspect, the invention provides a waterborne polymer-based adhesive, comprising, by mass, 35-45 parts of a polymer I, 25-40 parts of a polymer II, 10-25 parts of a polymer III, 1-5 parts of a colloid stabilizer, 0.2-2 parts of a pH regulator and water;
the polymer I is CH 2 =CH-COOR 1 Polymerized from monomers, R is 1 Is H or C 1 -C 8 Is a paraffin group;
the polymer II is CH 2 =C(CH 3 )-COOR 2 、CH(R 3 )=C(R 4 )-C 6 H 4 (R 5 ) And CH (R) 6 )=CH(R 7 ) At least two monomers of (C), R is polymerized 2 Is H or C 1 -C 8 Is an alkanyl radical of R 3 、R 4 And R is 5 Are all H or C 1 -C 2 Is an alkanyl radical of R 6 Is H or C 1 -C 10 Is an alkanyl radical of R 7 Cyano, carboxyl or amino;
the polymer III is CH 2 =C(R 8 )-CO-N(R 9 )(R 10 )、CH(R 11 )=C(R 12 )-COO-R 13 -OH、CH(R 14 )=C(R 15 )-COO-R 16 -(C 2 H 3 O)、CH(R 17 )=C(R 18 )-CO-N(R 19 )(R 20 -CO-R 21 ) And CH (R) 22 )=C(R 23 )-C 6 H 4 -C(R 24 )=CH(R 25 ) At least two monomers of (a) are polymerized, and R is 8 Is H or CH 3 The R is 9 And R is 10 Are all H or C 1 -C 10 Is an alkanyl radical of R 11 And R is 12 Are all H or C 1 -C 2 Is an alkanyl radical of R 13 Is C 1 -C 10 Is an alkanyl radical of R 14 And R is 15 Are all H or C 1 -C 2 Is an alkanyl radical of R 16 Is C 1 -C 10 Is an alkanyl radical of R 17 、R 18 And R is 19 Are all H or C 1 -C 2 Is an alkanyl radical of R 20 And R is 21 Are all C 1 -C 5 An alkanyl radical, said R 22 、R 23 、R 24 And R is 25 Are all H or C 1 -C 2 Is a hydrocarbon group.
The aqueous polymer-based binder of the present invention includes a polymer I, a polymer II and a polymer III. Wherein, the polymer I is polymerized acrylic ester by emulsion polymerization of one or more than two acrylic ester monomers in pure water medium, and the polymer acts as a soft chain structure in the invention. The adhesive also has the function of improving the flexibility of the adhesive and leading the system to have better extensibility. The glass transition temperature of the binder is adjusted so that the binder can keep better mechanical properties when being used at low temperature. The affinity of the binder to the electrolyte is improved, so that the system has good liquid absorption performance. Improving the adhesive property, the aging resistance and the like. The polymer II is a polymer hard chain structure formed by polymerizing one or more than two methacrylate monomers, styrene, acrylonitrile and other monomers in a pure water medium, can improve the cohesive force and mechanical strength of a system, plays a role in inhibiting pole piece rebound, improves the bonding strength, and has excellent chemical stability. The polymer III is formed by polymerizing one or more than two functional monomers such as acrylamide, hydroxyl-containing hydroxyalkyl acrylate, glycidyl acrylate, diketone acrylamide, divinylbenzene and the like or crosslinked divinylbenzene in pure water medium, and can modify a crosslinked structure and improve cohesive force. By introducing polar groups, the adhesion acting force on the current collector is improved; an auxiliary lithium ion transmission functional group containing N, O and other elements is introduced, so that the transmission performance of lithium ions in the binder is improved, and the cycle electrical performance is improved.
Preferably, said R 1 Is C 4 -C 8 An alkanyl group or an isomer thereof.
Preferably, said R 2 Is C 2 -C 4 Is an alkanyl radical of R 6 Is H or C 2 -C 5 Is a hydrocarbon group.
Preferably, the colloid stabilizer is at least one of polyvinyl alcohol, hydroxymethyl cellulose, hydroxyethyl cellulose and N-vinyl pyrrolidone, and the molecular weight of the colloid stabilizer is 3000-20000.
Preferably, the pH regulator is ammonia water, sodium bicarbonate, liOH, sodium hydroxide or organic ammonia.
Preferably, the preparation method of the polymer I comprises the following steps in parts by mass:
pre-emulsification: providing 50 to 60 parts of CH 2 =CH-COOR 1 Mixing monomer, pure water 40-50 weight portions, emulsifier 0.5-6 weight portions and initiator 0.1-1 weight portions, stirring to homogeneous, and adding CH while stirring 2 =CH-COOR 1 Monomer, preparing pre-emulsion;
preparation of Polymer I: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain the polymer I.
Preferably, in the pre-emulsification step, the emulsifier comprises an anionic emulsifier and/or a nonionic emulsifier, wherein the anionic emulsifier is at least one of sodium alkyl sulfonate, stearate and oleate, and the nonionic emulsifier is at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, sorbitan fatty acid ester and polyoxyethylene sorbitan fatty acid ester;
the initiator is at least one of ammonium persulfate, sodium persulfate, potassium persulfate and sodium peroxide.
Preferably, the preparation method of the polymer II comprises the following steps in parts by mass:
pre-emulsification: providing 40-50 parts by mass of polymer II monomer, 40-50 parts by mass of pure water, 0.5-6 parts by mass of emulsifier and 0.1-1 part by mass of initiator, firstly mixing 20-25 parts by mass of pure water and all the emulsifier, uniformly stirring, and then adding the polymer II monomer while stirring to prepare a pre-emulsion;
preparation of Polymer II: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain a polymer II;
the polymer II monomer comprises CH 2 =C(CH 3 )-COOR 2 、CH(R 3 )=C(R 4 )-C 6 H 4 (R 5 ) And CH (R) 6 )=CH(R 7 ) At least two monomers of (a).
Preferably, the preparation method of the polymer III comprises the following steps in parts by mass:
pre-emulsification: providing 40-50 parts by mass of polymer III monomer, 40-50 parts by mass of pure water, 0.5-6 parts by mass of emulsifier and 0.1-1 part by mass of initiator, firstly mixing 20-25 parts by mass of pure water and all the emulsifier, uniformly stirring, and then adding the polymer III monomer while stirring to prepare a pre-emulsion;
preparation of Polymer III: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain a polymer III;
the polymer III monomer comprises CH 2 =C(R 8 )-CO-N(R 9 )(R 10 )、CH(R 11 )=C(R 12 )-COO-R 13 -OH、CH(R 14 )=C(R 15 )-COO-R 16 -(C 2 H 3 O)、CH(R 17 )=C(R 18 )-CO-N(R 19 )(R 20 -CO-R 21 ) And CH (R) 22 )=C(R 23 )-C 6 H 4 -C(R 24 )=CH(R 25 ) At least two of them.
In a second aspect, the invention also provides a negative electrode comprising the aqueous polymer-based binder according to the first aspect of the invention.
The negative electrode according to the second aspect of the present invention comprises: (1) Excellent flexibility and adhesion performance, and can effectively buffer structural stress caused by lithium ion intercalation/deintercalation in the charge and discharge process, and prevent the electrode from falling off or breaking.
(2) The electrolyte interface film also has excellent chemical stability and good hygroscopicity, promotes the rapid formation of the electrolyte interface film between the electrolyte and the electrode, and can also prevent the depletion of the electrolyte in the subsequent circulation process. (3) The lithium ion battery has excellent conductivity and cycle stability, and the transmission performance of lithium ions in the binder is improved by introducing auxiliary lithium ion transmission functional groups containing N, O and other elements, and meanwhile, the capacitance retention rate in the cycle process of the lithium ion battery is improved.
Advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments of the invention.
Detailed Description
The following description is of the preferred embodiments of the present invention, and it should be noted that it will be apparent to those skilled in the art that modifications and variations can be made without departing from the principle of the invention, and these modifications and variations are also regarded as the scope of the invention.
The aqueous polymer-based binder of the present invention, the method of preparing the same, and the negative electrode including the same are described in detail below by way of specific examples.
Example 1
Preparation of Polymer I: (1) Adding 9kg of pure water and 0.25kg of sodium dodecyl benzene sulfonate into a pre-emulsifying tank, stirring thoroughly and dispersing uniformly, adding 18kg of butyl acrylate while stirring, and continuing stirring for 50min after the addition is finished to obtain stable and uniform pre-emulsifying liquid. (2) 8kg of the pre-emulsion and 9kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 75 ℃, and 0.03kg of sodium persulfate is added and the temperature is kept for 30min. Continuously heating to 80 ℃ and keeping the temperature constant for 30min, starting to dropwise add the residual pre-emulsion in the first step, controlling the dropwise adding speed to be 150min, adding 0.03kg of sodium persulfate in the middle after dropwise adding, and keeping the temperature constant for 60min at 86 ℃ after dropwise adding to obtain the emulsion of the polymer I.
Preparation of Polymer II: (1) Adding 12kg of pure water and 0.3kg of sodium dodecyl benzene sulfonate into a pre-emulsifying tank, stirring and dispersing uniformly, adding 10kg of butyl methacrylate and 10kg of styrene while stirring, and continuing stirring for 60min after the addition is finished to obtain a stable and uniform pre-emulsifying liquid. (2) 9kg of the pre-emulsion and 12kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 75 ℃, and 0.03kg of sodium persulfate is added and the temperature is kept for 30min. Continuously heating to 80 ℃ and keeping the temperature constant for 30min, starting to dropwise add the residual pre-emulsion in the first step, controlling the dropwise adding speed to be 150min, adding 0.03kg of sodium persulfate in the middle after dropwise adding, and keeping the temperature constant for 60min at 86 ℃ after dropwise adding to obtain the polymer II emulsion.
Preparation of Polymer III: (1) Adding 4kg of pure water and 0.05kg of sodium dodecyl benzene sulfonate into a pre-emulsifying tank, stirring and dispersing uniformly, adding 5kg of acrylic acid-N, N-dimethylaminoethyl ester and 3kg of glycidyl methacrylate while stirring, and continuing stirring for 60min after the addition is finished to obtain stable and uniform pre-emulsifying liquid. (2) 3kg of the pre-emulsion and 4kg of pure water are added into a reaction kettle together, stirred and heated to 75 ℃, added with 0.01kg of ammonium persulfate and kept for 30min. Continuously heating to 80 ℃ and keeping the temperature for 30min, starting to drop the residual pre-emulsion in the first step, controlling the drop speed to be 150min, adding 0.01kg of ammonium persulfate in the middle after the drop, and keeping the temperature at 86 ℃ for reaction for 60min after the drop is finished, so as to obtain the polymer III emulsion.
Preparation of an aqueous polymer-based binder: and adding the prepared polymer I emulsion, polymer II emulsion, polymer III emulsion, 3kg of hydroxyethyl cellulose and 1kg of baking soda into an emulsifying tank while stirring, controlling the temperature of the emulsifying tank to be not higher than 45 ℃, and stirring and dispersing in the emulsifying tank for 60min to obtain the water-based polymer-based adhesive.
Preparing a lithium ion battery cathode: a coating slurry of the surface of the current collector was prepared by homogenizing 50kg of graphite, 1kg of conductive carbon black, 4kg of the above aqueous polymer-based binder and 45kg of pure water in a double planetary mixer. The coating slurry is coated on the surface of the current collector copper foil through an automatic coating machine, and the negative plate with the coating thickness of 60-120 nm is prepared. The negative plate can be subjected to peel strength and battery cycle performance test through baking and rolling.
Example 2
Preparation of Polymer I: (1) Adding 10kg of pure water and 0.35kg of sodium dodecyl sulfate into a pre-emulsifying tank, stirring thoroughly and dispersing uniformly, adding 20kg of 2-ethylhexyl acrylate while stirring, and continuing stirring for 60min after the addition is finished to obtain a stable and uniform pre-emulsifying liquid. (2) 6kg of the pre-emulsion and 10kg of pure water are added into a reaction kettle together, stirred and heated to 72 ℃, added with 0.04kg of ammonium persulfate and kept for 30min. Continuously heating to 80 ℃ and keeping the temperature constant for 30min, starting to dropwise add the residual pre-emulsion in the first step, controlling the dropwise adding speed to be 180min, adding 0.03kg of sodium persulfate in the middle, and keeping the temperature constant for 60min at 86 ℃ after the dropwise adding is finished to obtain the emulsion of the polymer I.
Preparation of Polymer II: (1) Adding 9kg of pure water and 0.3kg of sodium dialkyl succinate sulfonate into a pre-emulsifying tank, stirring and dispersing uniformly, adding 5kg of methyl methacrylate and 10kg of styrene while stirring, and continuing stirring for 60min after the adding is finished to obtain stable and uniform pre-emulsion. (2) 5kg of the pre-emulsion and 9kg of pure water are added into a reaction kettle together, stirred and heated to 75 ℃, added with 0.02kg of ammonium persulfate and kept for 30min. Continuously heating to 80 ℃ and keeping the temperature for 30min, starting to drop the residual pre-emulsion in the first step, controlling the drop speed to be 180min, adding 0.02kg of ammonium persulfate in the middle, and keeping the temperature at 86 ℃ for 30min after the drop is finished, so as to obtain the polymer II emulsion.
Preparation of Polymer III: (1) Adding 5kg of pure water and 0.1kg of sodium dialkyl succinate sulfonate into a pre-emulsifying tank, stirring and dispersing uniformly, adding 5kg of hydroxyethyl acrylate and 5kg of glycidyl methacrylate while stirring, and continuing stirring for 40min after the adding is finished to obtain a stable and uniform pre-emulsifying liquid. (2) 4kg of the pre-emulsion and 5kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 75 ℃, and 0.01kg of ammonium persulfate is added and the temperature is kept for 30min. Continuously heating to 80 ℃ and keeping the temperature constant for 45min, starting to drop the residual pre-emulsion in the first step, controlling the drop speed to be 150min, adding 0.01kg of ammonium persulfate in the middle after the drop, and keeping the temperature constant for 40min at 84 ℃ after the drop is finished, so as to obtain the polymer III emulsion.
Preparation of an aqueous polymer-based binder: adding the prepared polymer I emulsion, polymer II emulsion, polymer III emulsion, 4kg of hydroxyethyl cellulose and 0.8kg of ammonia water (ammonia content is 25%) into an emulsifying tank while stirring, controlling the temperature of the emulsifying tank to be not higher than 45 ℃, and stirring and dispersing in the emulsifying tank for 60min to obtain the water-based polymer binder.
Preparing a lithium ion battery cathode: a coating slurry of the surface of the current collector was prepared by homogenizing 50kg of graphite, 1kg of conductive carbon black, 4kg of the above aqueous polymer-based binder and 45kg of pure water in a double planetary mixer. The coating slurry is coated on the surface of the current collector copper foil through an automatic coating machine, and the negative plate with the coating thickness of 60-120 nm is prepared. The negative plate can be subjected to peel strength and battery cycle performance test through baking and rolling.
Example 3
Preparation of Polymer I: (1) 10kg of pure water and 0.35kg of sodium dodecyl sulfate are added into a pre-emulsifying tank, after the mixture is fully stirred and uniformly dispersed, 21kg of ethyl acrylate is added while stirring, and stirring is continued for 60min after the addition is completed, so that stable and uniform pre-emulsion is obtained. (2) 8kg of the pre-emulsion and 10kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 70 ℃, and 0.03kg of sodium peroxide is added and the temperature is kept for 30min. Continuously heating to 80 ℃ and keeping the temperature constant for 30min, starting to dropwise add the residual pre-emulsion in the first step, controlling the dropwise adding speed to be 180min, adding 0.03kg of sodium peroxide in the middle, and keeping the temperature constant for 30min at 86 ℃ after the dropwise adding is finished to obtain the emulsion of the polymer I.
Preparation of Polymer II: (1) 10kg of pure water and 0.3kg of sodium dialkyl succinate sulfonate are added into a pre-emulsifying tank, after being fully stirred and uniformly dispersed, 10kg of butyl methacrylate and 7kg of acrylonitrile are added while stirring, and stirring is continued for 60min after the addition is finished, so that stable and uniform pre-emulsion is obtained. (2) 7kg of the pre-emulsion and 10kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 75 ℃, and 0.02kg of ammonium persulfate is added and the mixture is kept for 30min. Continuously heating to 80 ℃ and keeping the temperature for 30min, starting to drop the residual pre-emulsion in the first step, controlling the drop speed to be 180min, adding 0.02kg of ammonium persulfate in the middle, and keeping the temperature at 84 ℃ for reacting for 45min after the drop is finished to obtain the polymer II emulsion.
Preparation of Polymer III: (1) Adding 5kg of pure water and 0.1kg of sodium dialkyl succinate sulfonate into a pre-emulsifying tank, stirring thoroughly and dispersing uniformly, adding 8kg of acetylacetone acrylamide while stirring, and continuing stirring for 40min after the addition to obtain stable and uniform pre-emulsifying liquid. (2) 3kg of the pre-emulsion and 5kg of pure water are taken and added into a reaction kettle together, the mixture is stirred and heated to 75 ℃, and 0.02kg of ammonium persulfate is added and the mixture is kept for 30min. Continuously heating to 82 ℃ and keeping the temperature constant for 45min, starting to dropwise add the residual pre-emulsion in the first step, controlling the dropwise adding speed to be 120min, adding 0.02kg of ammonium persulfate in the middle, and keeping the temperature constant for reaction for 30min at 84 ℃ after the dropwise adding is finished, so as to obtain the polymer III emulsion.
Preparation of an aqueous polymer-based binder: adding the prepared polymer I emulsion, polymer II emulsion, polymer III emulsion, 3kg of polyvinyl alcohol and 0.6kg of sodium hydroxide into an emulsifying tank while stirring, controlling the temperature of the emulsifying tank to be not higher than 45 ℃, and stirring and dispersing in the emulsifying tank for 60min to obtain the water-based polymer-based adhesive.
Preparing a lithium ion battery cathode: a coating slurry of the surface of the current collector was prepared by homogenizing 50kg of graphite, 1kg of conductive carbon black, 4kg of the above aqueous polymer-based binder and 45kg of pure water in a double planetary mixer. The coating slurry is coated on the surface of the current collector copper foil through an automatic coating machine, and the negative plate with the coating thickness of 60-120 nm is prepared. The negative plate can be subjected to peel strength and battery cycle performance test through baking and rolling.
Comparative example 1: and (3) replacing the aqueous polymer-based binder with the ordinary styrene-butadiene rubber emulsion (SBR) to prepare the lithium ion battery cathode.
Comparative example 2: polyacrylate emulsion (PAA), the common styrene-butadiene rubber emulsion is used for replacing the water-based polymer binder to prepare the lithium ion battery cathode.
Effect example 1: solid content and viscosity detection
3g of the aqueous polymer-based binder emulsion prepared in examples 1 to 3 and the emulsion prepared in comparative examples 1 to 2 were weighed and put into an oven at 110℃and a vacuum of-0.09 MPa for baking for 24 hours to make the emulsion sample lose moisture, and then the mass difference of the sample was weighed, and the solid content was calculated from the mass difference, and the results are shown in Table 1.
The viscosity of the aqueous polymer-based binder emulsion as well as the emulsions in comparative examples 1-2 was measured by rotating a cylindrical rotor and a cylindrical vessel, the rotational speed of the cylindrical rotor was 12rpm, and the results of the viscosity test are shown in Table 1.
TABLE 1 results of solids content and viscosity tests
As can be seen from the results in Table 1, the aqueous polymer-based adhesive emulsions prepared in examples 1 to 3 have higher solid contents than those in comparative examples 1 to 2, and the aqueous polymer-based adhesive having high solid contents has good solubility, high dissolution rate and high solubility, and the aqueous polymer-based adhesive having high solid contents has higher viscosity and viscosity stability, and the adhesion and tensile properties are improved. In addition, the viscosity of the aqueous polymer-based binders prepared in examples 1-3 was intermediate between that of conventional SBR and PAA, facilitating homogenization and maintaining slurry stability.
Effect example 2: peel strength test
The electrodes of examples 1-3 and comparative examples 1-2 were placed on a tensile tester to conduct 180 ° peel test of the electrodes. The experimental results are shown in table 2.
TABLE 2 peel strength test results
Contrast item The negative plate is strongly strippedDegree (N/25 mm)
Example 1 2~5
Example 2 2~7
Example 3 2~7
Styrene-butadiene emulsion (SBR) 0.1~0.5
Polyacrylate emulsion (PAA) 0.1~0.3
As can be seen from the results of table 2, the aqueous polymer-based binders prepared in examples 1 to 3 had better peel strength than comparative examples 1 to 2, indicating that the negative electrode was able to more effectively relieve structural stress generated by lithium ion intercalation/deintercalation during charge and discharge, preventing the active material from falling off and even breaking the electrode.
Effect example 3: battery cycle performance test
The batteries were assembled using the negative electrodes of the batteries of examples 1 to 3 and comparative examples 1 to 2, in which the counter electrode was a metallic lithium sheet and the electrolyte was 1M LiPF 6 Is dissolved in diethyl carbonate and dimethyl carbonate (1:1) for testing the cycle performance of the battery. The specific test method is as follows: charging to 4.2V with constant current and constant voltage of 0.5C, and stopping current of 0.05C; the discharging mode is to discharge to 3.0V with a constant current of 1.0C. And standing for 10min. The capacity retention of the cells after 1000 weeks of cycling was measured and the results are shown in table 3.
Table 3 battery cycle performance test results
Contrast item Battery cycle life (1000 week capacity retention%)
Example 1 88~90
Example 2 87~89
Example 3 88~90
Styrene-butadiene emulsion (traditional SBR) 60~70
Polyacrylate emulsion (PAA) 70~80
As can be seen from the results in table 3, compared with comparative examples 1-2, the batteries corresponding to the aqueous polymer-based binders prepared in examples 1-3 have more excellent cycle performance, and after the batteries are subjected to charge and discharge cycles of 1000 weeks, the capacity retention rate of the batteries corresponding to examples 1-3 is still maintained to be 87% or more, which is significantly higher than that of the batteries corresponding to comparative examples 1-2, indicating that the aqueous polymer-based binders prepared in the present application have more excellent cycle stability when applied to the preparation of batteries.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (10)

1. The water-based polymer-based adhesive is characterized by comprising, by mass, 35-45 parts of a polymer I, 25-40 parts of a polymer II, 10-25 parts of a polymer III, 1-5 parts of a colloid stabilizer, 0.2-2 parts of a pH regulator and water;
the polymer I is CH 2 =CH-COOR 1 Polymerized from monomers, R is 1 Is H or C 1 -C 8 Is a paraffin group;
the polymer II is CH 2 =C(CH 3 )-COOR 2 、CH(R 3 )=C(R 4 )-C 6 H 4 (R 5 ) And CH (R) 6 )=CH(R 7 ) At least two monomers of (C), R is polymerized 2 Is H or C 1 -C 8 Is an alkanyl radical of R 3 、R 4 And R is 5 Are all H or C 1 -C 2 Is an alkanyl radical of R 6 Is H or C 1 -C 10 Is an alkanyl radical of R 7 Cyano, carboxyl or amino;
the polymer III is CH 2 =C(R 8 )-CO-N(R 9 )(R 10 )、CH(R 11 )=C(R 12 )-COO-R 13 -OH、CH(R 14 )=C(R 15 )-COO-R 16 -(C 2 H 3 O)、CH(R 17 )=C(R 18 )-CO-N(R 19 )(R 20 -CO-R 21 ) And CH (R) 22 )=C(R 23 )-C 6 H 4 -C (R 24 )=CH(R 25 ) At least two monomers of (a) are polymerized, and R is 8 Is H or CH 3 The R is 9 And R is 10 Are all H or C 1 -C 10 Is an alkanyl radical of R 11 And R is 12 Are all H or C 1 -C 2 Is an alkanyl radical of R 13 Is C 1 -C 10 Is an alkanyl radical of R 14 And R is 15 Are all H or C 1 -C 2 Is an alkanyl radical of (2)R 16 Is C 1 -C 10 Is an alkanyl radical of R 17 、R 18 And R is 19 Are all H or C 1 -C 2 Is an alkanyl radical of R 20 And R is 21 Are all C 1 -C 5 An alkanyl radical, said R 22 、R 23 、R 24 And R is 25 Are all H or C 1 -C 2 Is a hydrocarbon group.
2. The aqueous polymer-based binder of claim 1 wherein R 1 Is C 4 -C 8 An alkanyl group or an isomer thereof.
3. The aqueous polymer-based binder of claim 1 wherein R 2 Is C 2 -C 4 Is an alkanyl radical of R 6 Is H or C 2 -C 5 Is a hydrocarbon group.
4. The aqueous polymer-based adhesive according to claim 1, wherein the colloidal stabilizer is at least one of polyvinyl alcohol, hydroxymethyl cellulose, hydroxyethyl cellulose and N-vinylpyrrolidone, and the molecular weight of the colloidal stabilizer is 3000 to 20000.
5. The aqueous polymer-based binder of claim 1, wherein the pH adjuster is aqueous ammonia, baking soda, liOH, sodium hydroxide, or organic ammonia.
6. An aqueous polymer-based adhesive according to any one of claims 1 to 5, wherein the preparation method of the polymer i comprises the following steps in parts by mass:
pre-emulsification: providing 50 to 60 parts of CH 2 =CH-COOR 1 Mixing monomer, pure water 40-50 weight portions, emulsifier 0.5-6 weight portions and initiator 0.1-1 weight portions, stirring to homogeneous, and adding CH while stirring 2 =CH-COOR 1 Monomer, preparing pre-emulsion;
preparation of Polymer I: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain the polymer I.
7. The aqueous polymer-based binder according to claim 6, wherein in the pre-emulsification step, the emulsifier comprises an anionic emulsifier and/or a nonionic emulsifier, the anionic emulsifier being at least one of sodium alkyl sulfonate, stearate, and oleate, the nonionic emulsifier being at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester;
the initiator is at least one of ammonium persulfate, sodium persulfate, potassium persulfate and sodium peroxide.
8. The aqueous polymer-based adhesive according to any one of claims 1 to 5, wherein the preparation method of the polymer ii comprises the following steps in parts by mass:
pre-emulsification: providing 40-50 parts by mass of polymer II monomer, 40-50 parts by mass of pure water, 0.5-6 parts by mass of emulsifier and 0.1-1 part by mass of initiator, firstly mixing 20-25 parts by mass of pure water and all the emulsifier, uniformly stirring, and then adding the polymer II monomer while stirring to prepare a pre-emulsion;
preparation of Polymer II: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain a polymer II;
the polymer II monomer comprises CH 2 =C(CH 3 )-COOR 2 、CH(R 3 )=C(R 4 )-C 6 H 4 (R 5 ) And CH (R) 6 )=CH(R 7 ) At least two monomers of (a).
9. An aqueous polymer-based adhesive according to any one of claims 1 to 5, wherein the preparation method of the polymer iii comprises the following steps in parts by mass:
pre-emulsification: providing 40-50 parts by mass of polymer III monomer, 40-50 parts by mass of pure water, 0.5-6 parts by mass of emulsifier and 0.1-1 part by mass of initiator, firstly mixing 20-25 parts by mass of pure water and all the emulsifier, uniformly stirring, and then adding the polymer III monomer while stirring to prepare a pre-emulsion;
preparation of Polymer III: adding 20-25 parts of pure water and 20-30% of the pre-emulsion into a reaction kettle, stirring and heating to 70-76 ℃, adding 0.03-0.5 part of initiator, preserving heat for 30-60 min, then dropwise adding the rest of the pre-emulsion and the rest of the initiator into the reaction kettle, and preserving heat for 30-60 min at 80-86 ℃ to obtain a polymer III;
the polymer III monomer comprises CH 2 =C(R 8 )-CO-N(R 9 )(R 10 )、CH(R 11 )=C(R 12 )-COO-R 13 -OH、CH(R 14 )=C(R 15 )-COO-R 16 -(C 2 H 3 O)、CH(R 17 )=C(R 18 )-CO-N(R 19 )(R 20 -CO-R 21 ) And CH (R) 22 )=C(R 23 )-C 6 H 4 -C (R 24 )=CH(R 25 ) At least two of them.
10. A negative electrode comprising the aqueous polymer-based binder of any one of claims 1 to 5.
CN202410036117.9A 2024-01-10 2024-01-10 Aqueous polymer-based binder and negative electrode Pending CN117820985A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202410036117.9A CN117820985A (en) 2024-01-10 2024-01-10 Aqueous polymer-based binder and negative electrode

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202410036117.9A CN117820985A (en) 2024-01-10 2024-01-10 Aqueous polymer-based binder and negative electrode

Publications (1)

Publication Number Publication Date
CN117820985A true CN117820985A (en) 2024-04-05

Family

ID=90522764

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202410036117.9A Pending CN117820985A (en) 2024-01-10 2024-01-10 Aqueous polymer-based binder and negative electrode

Country Status (1)

Country Link
CN (1) CN117820985A (en)

Similar Documents

Publication Publication Date Title
CN110233235B (en) Negative pole piece and electrochemical device
KR20170097577A (en) Aqueous binder for negative electrode of lithium ion battery and the preparation method thereof
CN104362348A (en) Negative electrode film and lithium ion battery applying same
EP2592678A1 (en) Binder resin composition for electrode of non-aqueous electrolyte battery, slurry composition, electrode and battery each containing the binder resin composition
CN115572557B (en) Adhesive and battery comprising same
US20230295410A1 (en) Dispersant for lithium ion battery and preparation method thereof, positive slurry, and lithium ion battery
CN115332540B (en) Negative electrode binder for secondary battery and preparation method thereof
CN111969211A (en) Negative plate of lithium ion battery capable of being rapidly charged at low temperature, lithium ion battery and preparation method
CN115386033A (en) Binder for lithium ion battery and lithium ion battery using same
CN115881968A (en) Non-fluorine positive electrode adhesive and preparation method and application thereof
CN115044331B (en) Water-dispersible polymer microparticle emulsion binder for lithium ion battery and preparation method thereof
CN112029452B (en) Preparation method and application of adhesive capable of improving battery rate performance
CN110492101B (en) Lithium ion battery cathode binder and preparation method and application thereof
CN117039180A (en) In-situ polymerization semi-solid battery and preparation method thereof
CN117264571A (en) Water-based binder for improving performance of graphite negative electrode and preparation method thereof
CN117417474A (en) Negative electrode additive for lithium battery
CN116891548A (en) Post-crosslinking aqueous adhesive special for lithium battery and preparation method and application thereof
CN117089017A (en) Non-fluorine binder for positive electrode of lithium ion battery, positive electrode using same and battery
CN117004353A (en) Modified binder and preparation method and application thereof
CN116247214A (en) Dispersing auxiliary, preparation method and application thereof
CN117820985A (en) Aqueous polymer-based binder and negative electrode
CN112375179B (en) Bimolecular-weight-distribution binder for negative electrode and preparation method and application thereof
CN114142040B (en) Silicon-based material binder for negative electrode of lithium battery
CN114512671B (en) Crosslinking type binder and preparation method and application thereof
CN114478958B (en) Modified SBR binder and preparation method and application thereof

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