CN116314792A - Dry electrode binder, negative electrode dry powder mixture and application thereof - Google Patents

Dry electrode binder, negative electrode dry powder mixture and application thereof Download PDF

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Publication number
CN116314792A
CN116314792A CN202310059894.0A CN202310059894A CN116314792A CN 116314792 A CN116314792 A CN 116314792A CN 202310059894 A CN202310059894 A CN 202310059894A CN 116314792 A CN116314792 A CN 116314792A
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dry
diisocyanate
linking agent
cross
binder
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岳敏
袁健
杨胜林
刘俊
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Shenzhen Yanyi New Materials Co Ltd
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Shenzhen Yanyi New Materials Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/022425—Electrodes for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • 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
    • H01M4/04—Processes of manufacture in general
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • 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 invention provides a dry electrode binder, a negative electrode dry powder mixture and application thereof, wherein the dry electrode binder is a polymer binder, and polymerization monomers of the polymer binder comprise isocyanate monomers, polyalcohol monomers, other hydroxyl-containing monomers and cross-linking agent monomers, and the other hydroxyl-containing monomers are at least one of hydroxyl acrylate resin or hydroxyl liquid nitrile rubber. The negative electrode dry powder mixture includes an active material, a conductive agent, and the dry electrode binder. The dry electrode binder provided by the invention has good binding power and good ionic conductivity, and forms a negative electrode dry powder mixture with active substances in an in-situ polymerization mode, and dry mixing is adopted in the dry electrode preparation process, so that the mixing condition is mild, the defect that the dry electrode preparation process using PTFE needs to be mixed in a high-pressure high-shear mixing tank is overcome, and the dry electrode technology can be applied to the field of lithium ion batteries.

Description

Dry electrode binder, negative electrode dry powder mixture and application thereof
Technical Field
The invention belongs to the technical field of electrode materials, and relates to a dry electrode binder, a negative electrode dry powder mixture and application thereof.
Background
The current commercialized product of the dry electrode technology is a super capacitor, but the lithium ion battery applying the dry electrode technology does not have the commercialized product at present, on one hand, because the binder system of the dry electrode is not completely suitable for the lithium ion battery system. The adhesive applied to the dry electrode technology at present is mainly PTFE, and can be used for fiberizing under high pressure and high shear to bond active substances.
CN111919315a discloses a dry electrode film comprising: a dry active material and a dry binder comprising a fibrillatable binder and a particulate non-fibrillatable binder having a D50 particle size of about 0.5 to 40 μm, and wherein the dry electrode film is free-standing, wherein the fibrillatable binder comprises Polytetrafluoroethylene (PTFE). However, the current dry electrode preparation process with PTFE requires mixing in a high pressure high shear batch tank, fibrillation of the PTFE with high shear, uniform mixing with active material, and high pressure extrusion coating onto the current collector. This results in the difficulty of achieving application in the field of lithium ion batteries using dry electrode technology with such binders.
In the art, it is desirable to develop a dry electrode binder system that is not PTFE, overcomes the disadvantages of the need to mix materials in a high pressure, high shear batch tank during the dry electrode preparation process using PTFE, and provides good cell performance.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a dry electrode binder, a negative electrode dry powder mixture and application thereof. The dry electrode binder has good binding power and good ionic conductivity, has mild mixing conditions in the dry electrode preparation process, and overcomes the defect that the dry electrode preparation process using PTFE needs to be mixed in a high-pressure high-shear mixing tank.
To achieve the purpose, the invention adopts the following technical scheme:
in one aspect, the invention provides a dry electrode binder, wherein the dry electrode binder is a polymer binder, and the polymer monomers of the polymer binder comprise isocyanate monomers, polyol monomers, other hydroxyl-containing monomers and cross-linking agent monomers, and the other hydroxyl-containing monomers are at least one of hydroxyl acrylate resins or hydroxyl liquid nitrile rubbers.
In the invention, the dry electrode binder can also be called as a modified polyurethane dry electrode binder, and the modified polyurethane dry electrode binder obtained by selecting isocyanate monomer and polyol monomer, at least one of hydroxy acrylic ester or hydroxy liquid nitrile rubber and cross-linking agent monomer has better binding force and better ionic conductivity, can replace a PTFE system, has mild mixing condition in the dry electrode preparation process, and overcomes the defect that the dry electrode preparation process using PTFE needs to be mixed in a high-pressure high-shear mixing tank.
In the present invention, polyurethane (PU) is a short polyurethane, which is formed by polyaddition of a polyisocyanate and a polyhydroxy polymer, and is a polymer compound having a plurality of repeating urethane segments (-NHCOO-) in a polymer main chain. The materials selected in the invention are polyisocyanate and polyhydroxy polymer (low molecular weight polymer).
In the present invention, the polymer monomer is liquid, but after the reaction, the resulting binder is in a solid state, which also exactly meets the requirements of the dry electrode binder used to prepare the dry electrode. The dry electrode binder plays a role in binding active substances (such as graphite) or active substances (such as graphite) with current collectors when preparing a negative electrode dry powder mixture with active substances or preparing a dry electrode negative electrode, meanwhile, the binder is required to have good flexibility and cohesion, the modified polyurethane dry electrode binder can just meet the requirements, and the solvent-free modified polyurethane dry electrode binder can be prepared and can be uniformly mixed with the active substances (such as graphite).
In the invention, after the polymer monomer of the polymer binder is mixed with the active substance (such as graphite) and the conductive agent, the uniform mixing with the active substance can be ensured, and the polymer monomer is polymerized on the surfaces of the active substance and the conductive agent to obtain the polymer binder, so that the binder can be uniformly distributed in the active substance (such as graphite) and the conductive agent, and part of isocyanate can also react with active groups such as hydroxyl groups on the surface of the active substance (such as graphite) to increase the cohesiveness between the binder and the active substance (such as graphite).
The invention synthesizes solvent-free modified polyurethane dry electrode binder directly on the surface of active substance, adopts the reaction raw materials of modified polyurethane dry electrode binder isocyanate and the reactant of polyalcohol micromolecule to be directly mixed with the mixture of hydroxy acrylic ester or hydroxy liquid nitrile rubber and active substance, achieves the aim of evenly mixing the binder and the active substance, simultaneously, the hydroxy acrylic ester or hydroxy liquid nitrile rubber also reacts with isocyanate in the reaction of modified polyurethane dry electrode binder, the hydroxy in acrylic ester also participates in the reaction of modified polyurethane dry electrode binder, realizes the crosslinking of two binders, forms a crosslinking network with proper crosslinking degree, better adheres the active substance, and has higher cohesive force after being rolled into a graphite film.
In the invention, isocyanate groups in isocyanate monomers react with polyol to generate polyurethane, the isocyanate groups can also react with hydroxyl groups in hydroxy acrylic ester or hydroxy liquid nitrile rubber to generate modified polyurethane (such as polyurethane-acrylate and polyurethane-nitrile) which is uniformly distributed in active substances (such as graphite), so that the crosslinking of various binders is realized, a crosslinking network is formed with proper crosslinking degree, the active substances can be better bonded, and simultaneously, the isocyanate groups in the isocyanate react with active groups such as hydroxyl groups on the surface of the active substances (such as graphite) to increase the bonding property of the binder and the active substances (such as graphite).
The properties of the modified polyurethane material are greatly dependent on the phase structure of the soft and hard segments and the degree of microphase separation, and in the invention, the isocyanate monomer has the main function of providing the hard segment part and the cohesive force of the modified polyurethane dry electrode adhesive. Isocyanate is a compound with strong polarity, wherein the molecular chain end part of the compound contains-NCO groups, the-NCO groups have strong polarity and can react with active hydrogen such as water, hydroxyl, amino and the like to generate a plurality of crosslinking structures, and the polar groups can also interact to form strong hydrogen bonds, so that the overall cohesive force and rigidity of the polymer are improved, and the adhesive strength is improved. In the invention, the main function of the polyol monomer is to provide a soft segment part in a polyurethane structure, which can directly influence the performances of the modified polyurethane dry electrode adhesive, such as flexibility, temperature resistance and the like.
In the invention, the hydroxyl acrylic ester has good thermal stability, good electrochemical stability, stability in the redox environment of the lithium ion battery, no side reaction, good storage stability, convenient transportation and storage, and stability in electrolyte, so that the battery has good ploidy and excellent low-temperature performance.
In the invention, the liquid nitrile rubber has excellent mechanical properties, can improve the cohesive force of the adhesive, has good electrolyte resistance, better heat resistance and improves the bonding strength of the adhesive.
Preferably, the isocyanate monomer includes any one or a combination of at least two of Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1, 5-Naphthalene Diisocyanate (NDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene Diisocyanate (HDI), hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2, 4-trimethylhexamethylene diisocyanate (TMDI), xylylene Diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated Xylylene Diisocyanate (HXDI), isophorone diisocyanate (IPDI), 4' -dicyclohexylmethane diisocyanate (HMDI), methylcyclohexane diisocyanate (HTDI), 1, 4-benzene diisocyanate (PPDI), or norbornane diisocyanate (NBDI).
Preferably, the polyol monomers comprise any one or a combination of at least two of polyester polyols or polyether polyols. The polyester polyol contains a large amount of ester groups (-COO-), has extremely strong polarity, and the prepared modified polyurethane dry electrode adhesive has excellent performance and good heat resistance and oil resistance. The polyether polyol contains a large amount of ether groups (-COC-) and is not easy to hydrolyze, and the prepared modified polyurethane dry electrode adhesive has excellent hydrolysis resistance, good low temperature resistance and high molecular chain flexibility.
Preferably, the polyester polyol comprises a polycarbonate polyol.
Preferably, the hydroxyl acrylate resin has a number average molecular weight of 500 to 3000, such as 500, 1000, 1500, 1800, 2000, 2300, 2500, 2800, 3000, or the like.
Preferably, the hydroxy acrylate resin comprises any one or a combination of at least two of styrene (St), acrylic Acid (AA), butyl Acrylate (BA), butyl Methacrylate (BMA), hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) or hydroxypropyl acrylate (HPA).
The crosslinking agent in the invention has the function of carrying out grafting reaction with polyurethane forming monomers (isocyanate monomers and polyol monomers) to expand the molecular chain of polyurethane, thereby improving the molecular weight of polyurethane, and the addition of the crosslinking agent can improve the mechanical properties, the mechanical properties and the like of materials.
Preferably, the cross-linking agent monomer comprises any one or a combination of at least two of dihydric alcohol cross-linking agent, trihydric alcohol cross-linking agent, diamine cross-linking agent, alcohol amine cross-linking agent, alicyclic alcohol cross-linking agent, aromatic alcohol cross-linking agent, glycerin allyl ether, glycidyl allyl ether or dicumyl peroxide.
Preferably, the glycol cross-linking agent comprises any one or a combination of at least two of 1, 4-butanediol, ethylene glycol, propylene glycol, diethylene glycol or neopentyl glycol.
Preferably, the triol crosslinking agent comprises glycerol and/or trimethylolpropane.
Preferably, the diamine cross-linking agent comprises any one or a combination of at least two of 3, 3-dichloro-4, 4-diaminodiphenylmethane, 3, 5-dimethylthiotoluenediamine, 3, 5-diethyltoluenediamine, 2, 4-diamino-3, 5-dimethylthiochlorobenzene or isophorone diamine.
Preferably, the alcohol amine cross-linking agent comprises any one or a combination of at least two of ethanolamine, diethanolamine, triethanolamine or N, N-bis (2-hydroxypropyl) aniline.
Preferably, the cycloaliphatic alcohol cross-linking agent comprises 1, 4-cyclohexanediol and/or hydrogenated bisphenol a.
Preferably, the aromatic alcohol crosslinking agent comprises any one or a combination of at least two of dimethylene phenyl glycol, hydroquinone bis-beta-hydroxyethyl ether or resorcinol hydroxy ether.
Preferably, the number average molecular weight of the dry electrode binder is 30000-80000, e.g., 30000, 40000, 50000, 60000, 70000 or 80000.
In another aspect, the present invention provides a negative electrode dry powder mixture comprising an active material, a conductive agent, and a dry electrode binder as described above, the dry electrode binder coating the active material and the conductive agent surfaces.
Preferably, the dry electrode binder is obtained by in situ polymerization on the surface of the active material and the conductive agent.
In-situ polymerization is to directly mix the binder reaction monomer with the active substance, and polymerize the binder reaction monomer on the surface of the active substance to achieve the aim of uniformly mixing the binder and the active substance.
In-situ polymerization is different from general polymerization in that a binder having a large molecular weight is synthesized alone and then mixed with or coated on an adherend. The synthetic binders, which are generally polymerized, cannot be homogeneously mixed with active substances (e.g., graphite) having a size of tens of micrometers. The monomer with small molecular weight can be uniformly mixed with active substances in the in-situ polymerization, then the monomer is polymerized on the surface of the active substances to form a binder with large molecular weight, and the binder with large molecular weight is uniformly mixed among the active substances.
According to the invention, the dry electrode binder is obtained by in-situ polymerization on the surfaces of the active substances and the conductive agent, so that the purpose of uniformly mixing the binder with the active substances and the conductive agent is achieved, and meanwhile, the hydroxy acrylic ester or hydroxy liquid nitrile rubber also reacts with isocyanate in the modified polyurethane dry electrode binder reactant, so that a crosslinked network is formed, the active substances are better bonded, and the graphite film has higher cohesive force after being rolled. The reactant directly reacts on the surface of the active substance (such as graphite) to obtain a polymer, and meanwhile, the reactant can also react with active groups such as hydroxyl groups and the like on the surface of the active substance (such as graphite), so that the adhesiveness between the binder and the active substance (such as graphite) is improved.
Preferably, the active material comprises one or a combination of at least two of graphite, silicon-based oxide, silicon carbon material, lithium titanate, graphene or tin-based composite oxide, preferably graphite;
preferably, the graphite comprises one or a combination of at least two of natural graphite, artificial graphite, amorphous carbon, or mesophase carbon microbeads;
preferably, the conductive agent comprises one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes or conductive carbon black;
preferably, the dry powder mixture of the negative electrode has an active material content of 93% -98.5% (93%, 94%, 95%, 96%, 97%, 98% or 98.5%) by weight, the dry electrode binder content of 1% -5% (e.g., 1%, 2%, 3%, 4% or 5%), and the conductive agent content of 0.5% -2% (e.g., 0.5%, 0.8%, 1%, 1.5%, 1.8% or 2%) by weight.
In another aspect, the present invention provides a method for preparing the negative electrode dry powder mixture as described above, the method comprising the steps of:
mixing a polymerization monomer, and then mixing the polymerization monomer with an active substance and a conductive agent, and carrying out polymerization reaction to obtain the negative electrode dry powder mixture, wherein the polymerization monomer comprises isocyanate monomer, polyalcohol monomer, other hydroxyl-containing monomers and cross-linking agent monomer, and the other hydroxyl-containing monomers are at least one of hydroxyl acrylate resin or hydroxyl liquid nitrile rubber.
In the invention, the polymer monomer is mixed firstly and then with the active substance and the conductive agent, thus enhancing the uniform mixing of the polymer monomer and the active substance, and then the polymer binder with large molecular weight is polymerized in situ, so that the polymer binder with large molecular weight is uniformly distributed among the active substances (such as graphite) with micron-sized. The core reason for this is to uniformly distribute the active material (e.g., graphite) among the active materials. If the binder is polymerized and then mixed with active materials (such as graphite), the binder is not dissolved, the binder viscosity is tens of thousands, which can lead to uneven distribution of the binder, too much or too little binder can not be rolled directly to prepare a dry electrode, or the uniformity of the prepared dry electrode is poor, resulting in larger difference of battery performance.
The invention synthesizes solvent-free modified polyurethane dry electrode binder directly on the surface of active substance, adopts the reaction raw materials of modified polyurethane dry electrode binder, namely isocyanate and the reactant of polyalcohol micromolecule to be directly mixed with the mixture of hydroxy acrylic ester or hydroxy liquid nitrile rubber and active substance, thus achieving the purpose of evenly mixing the binder with the active substance, simultaneously, the hydroxy acrylic ester or hydroxy liquid nitrile rubber also reacts with isocyanate in the reactant, hydroxyl in the acrylic ester also participates in the reaction of the modified polyurethane dry electrode binder, thus realizing the crosslinking of the two binders, the proper crosslinking degree of the two forms a crosslinking network, the active substance is better bonded, and the graphite film is formed by rolling.
In the invention, isocyanate groups in isocyanate monomers react with polyol to generate polyurethane, the isocyanate groups can also react with hydroxyl groups in hydroxy acrylic ester or hydroxy liquid nitrile rubber to generate modified polyurethane (such as polyurethane-acrylate and polyurethane-nitrile) which is uniformly distributed in active substances (such as graphite), so that the crosslinking of various binders is realized, a crosslinking network is formed with proper crosslinking degree, the active substances can be better bonded, and simultaneously, the isocyanate groups in the isocyanate react with active groups such as hydroxyl groups on the surface of the active substances (such as graphite) to increase the bonding property of the binder and the active substances (such as graphite).
Preferably, the isocyanate monomer includes any one or a combination of at least two of Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1, 5-Naphthalene Diisocyanate (NDI), dimethylbiphenyl diisocyanate (TODI), hexamethylene Diisocyanate (HDI), hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2, 4-trimethylhexamethylene diisocyanate (TMDI), xylylene Diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), hydrogenated Xylylene Diisocyanate (HXDI), isophorone diisocyanate (IPDI), 4' -dicyclohexylmethane diisocyanate (HMDI), methylcyclohexane diisocyanate (HTDI), 1, 4-benzene diisocyanate (PPDI), or norbornane diisocyanate (NBDI).
Preferably, the polyol monomers comprise any one or a combination of at least two of polyester polyols or polyether polyols.
Preferably, the polyester polyol comprises a polycarbonate polyol.
Preferably, the hydroxyl acrylate resin has a number average molecular weight of 500 to 3000, such as 500, 1000, 1500, 1800, 2000, 2300, 2500, 2800, 3000, or the like.
Preferably, the hydroxy acrylate resin comprises any one or a combination of at least two of styrene (St), acrylic Acid (AA), butyl Acrylate (BA), butyl Methacrylate (BMA), hydroxyethyl methacrylate (HEMA), hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) or hydroxypropyl acrylate (HPA).
Preferably, the polymerized monomer is a polymerized monomer subjected to a water removal treatment. For example, the polyol monomer and the crosslinker monomer are first subjected to a water removal treatment.
Preferably, the molar ratio of isocyanate groups in the isocyanate monomer to hydroxyl groups in the polyol monomer is from 1.2:1 to 4:1, for example 1.2:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1. According to experiments, a modified polyurethane dry electrode binder with proper hardness, flexibility and cohesion can be obtained in the range. Below 1.2:1, the content of soft polyol is too high and the hardness is low, resulting in too soft binder and insufficient cohesion. Higher than 4:1 can result in too high a hard segment content, and the resulting adhesive is too hard and lacks flexibility.
Preferably, the molar ratio of isocyanate groups in the isocyanate monomer to hydroxyl groups in the other hydroxyl-containing monomers is from 1.2:1 to 12:1, for example 1.2:1, 1.5:1, 2:1, 3:1, 5:1, 7:1, 9:1, 10:1 or 12:1. According to experiments, a modified polyurethane dry electrode binder with proper hardness, flexibility and cohesion can be obtained in the range. Too high a soft segment hydroxyl monomer content can result in a softer binder and low cohesion. The hardness isocyanate content is too high, so that the adhesive is hard and poor in flexibility. Meanwhile, the viscosity of the used hydroxybutyronitrile resin and the used hydroxyacrylic acid resin is higher, the use content is high, the viscosity of the mixed solution is high, the mixing uniformity with graphite is affected, and a certain proportion range is selected according to experiments.
Preferably, the cross-linking agent monomer comprises any one or a combination of at least two of dihydric alcohol cross-linking agent, trihydric alcohol cross-linking agent, diamine cross-linking agent, alcohol amine cross-linking agent, alicyclic alcohol cross-linking agent, aromatic alcohol cross-linking agent, glycerin allyl ether, glycidyl allyl ether or dicumyl peroxide.
Preferably, the glycol cross-linking agent comprises any one or a combination of at least two of 1, 4-butanediol, ethylene glycol, propylene glycol, diethylene glycol or neopentyl glycol.
Preferably, the triol crosslinking agent comprises glycerol and/or trimethylolpropane.
Preferably, the diamine cross-linking agent comprises any one or a combination of at least two of 3, 3-dichloro-4, 4-diaminodiphenylmethane, 3, 5-dimethylthiotoluenediamine, 3, 5-diethyltoluenediamine, 2, 4-diamino-3, 5-dimethylthiochlorobenzene or isophorone diamine.
Preferably, the alcohol amine cross-linking agent comprises any one or a combination of at least two of ethanolamine, diethanolamine, triethanolamine or N, N-bis (2-hydroxypropyl) aniline.
Preferably, the cycloaliphatic alcohol cross-linking agent comprises 1, 4-cyclohexanediol and/or hydrogenated bisphenol a.
Preferably, the aromatic alcohol crosslinking agent comprises any one or a combination of at least two of dimethylene phenyl glycol, hydroquinone bis-beta-hydroxyethyl ether or resorcinol hydroxy ether.
Preferably, the molar ratio of isocyanate groups in the isocyanate monomer to reactive groups in the crosslinker is from 1.3:1 to 12:1, for example 1.3:1, 1.5:1, 2:1, 3:1, 5:1, 7:1, 8:1, 10:1, 11:1 or 12:1. The cross-linking agent plays a role of a hard segment in the modified polyurethane dry battery binder, and simultaneously plays a role of chain extension and molecular weight improvement and cohesive force improvement. The modified polyurethane dry battery adhesive is controlled in a proper range, and is also used for obtaining the modified polyurethane dry battery adhesive with good flexibility and good cohesion. Too low a cross-linking agent content can lead to insufficient chain extension, and the modified polyurethane dry cell adhesive has smaller molecular weight and small cohesive force. High levels of crosslinking agent also result in low molecular weight, and the adhesive is harder and less cohesive.
The active material comprises one or a combination of at least two of graphite, silicon-based oxide, silicon carbon material, lithium titanate, graphene or tin-based composite oxide, preferably graphite.
Preferably, the graphite comprises one or a combination of at least two of natural graphite, artificial graphite, amorphous carbon, or mesophase carbon microbeads.
Preferably, the conductive agent includes one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes, or conductive carbon black.
In the present invention, the mixing is performed by using a high-speed stirrer. In the invention, the in-situ polymerization mode is adopted, so that the low-viscosity liquid polymerization monomer and the active substance are uniformly dispersed under the high-speed shearing action to form the wet active substance, and then the dry solvent-free adhesive active substance composite material is formed after the polymerization reaction.
Preferably, the temperature of the polymerization reaction is 25-80 ℃, e.g., 25 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃ or 80 ℃.
Preferably, the polymerization reaction is carried out for a period of time of 1 to 7 days, for example 1 day, 2 days, 3 days, 4 days, 5 days, 6 days or 7 days.
Compared with the traditional wet slurry, the negative electrode dry powder mixture for the dry electrode has remarkable advantages in storage stability, transportation convenience and the like.
In another aspect, the present invention provides a dry electrode negative electrode comprising a negative electrode dry powder mixture as described above.
In another aspect, the present invention provides a method for preparing a dry electrode negative electrode as described above, the method comprising: and hot rolling the cathode dry powder mixture into a self-supporting film or directly hot rolling the self-supporting film onto a current collector to form a dry electrode cathode.
Preferably, the negative electrode dry powder mixture is subjected to grinding before hot rolling.
Preferably, the temperature of the hot rolling is in the range of 25-120 ℃, e.g. 25 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, 110 ℃ or 120 ℃.
The hot rolling process may be performed more than once to achieve a specific pole piece thickness and good adhesion to the current collector.
The negative electrode dry powder mixture is suitable for a dry electrode negative electrode process route of a pure dry method (dry mixing and dry coating), can ensure good dispersibility of active substances, and can realize a certain degree of deformation in the hot rolling process of the dry mixing process and the dry coating process, and the negative electrode dry powder mixture is deformed from a spherical structure to a non-spherical structure, so that a larger bonding area with active materials can be provided, higher bonding force is realized, and the process is different from a fibrillation process of PTFE, and generates a certain degree of deformation in the dry processing process, so that the bonding force is beneficial to improvement.
In another aspect, the present invention provides an electrochemical energy storage device comprising a dry electrode anode as described above;
preferably, the electrochemical energy storage device is selected from one of a lithium ion battery, a sodium ion battery, a supercapacitor, a fuel cell or a solar cell.
The dry electrode manufacturing process without solvation is realized in the whole process of the dry electrode preparation process, and the defect that the dry electrode preparation process using PTFE needs to be mixed in a high-pressure high-shear mixing tank can be overcome, so that the dry electrode technology can be applied to the field of lithium ion batteries or energy storage devices such as super capacitors.
Compared with the prior art, the invention has the following beneficial effects:
the dry electrode binder provided by the invention has good binding power and good ionic conductivity, the polymerization monomer of the dry electrode binder is mixed with the active substance and the conductive agent to achieve the purpose of uniform mixing, then an in-situ polymerization mode is adopted to form a negative electrode dry powder mixture with the active substance and the conductive agent, a dry electrode negative electrode is obtained by a dry preparation process, dry mixing is adopted in the dry electrode preparation process, the mixing condition is mild, and the defect that the dry electrode preparation process using PTFE needs to be mixed in a high-pressure high-shear batching tank is overcome, so that the dry electrode technology can be applied to the field of lithium ion batteries.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
Example 1
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymeric binder polymerized from polycarbonate polyol, hexamethylene diisocyanate trimer, hydroxy liquid nitrile rubber, and cross-linking agent 1, 4-butanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 21.18g of the dehydrated polycarbonate polyol (Ph-300, kogyo Co., ltd.), 2.82g of hexamethylene diisocyanate trimer, 0.252g of cross-linking agent 1, 4-butanediol and 2.27g of hydroxy liquid nitrile rubber (Jining Malus chemical Co., ltd TL 910) were added together to a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing and reacting for 7 days at 25 ℃ until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 2
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymer binder polymerized from polyether polyol, trimethylhexamethylene diisocyanate, hydroxyacrylate, and trimethylolpropane as a crosslinking agent as a polymerization monomer.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 22.14g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 1.86g of trimethyl hexamethylene diisocyanate, 0.273g of trimethylolpropane as a crosslinking agent and 1.37g of hydroxy acrylic ester (OX 7000L of Qingdao trade Co., ltd.) are added together into a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing and reacting for 7 days at 25 ℃ until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 3
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymer binder polymerized from polyether polyol, hexamethylene diisocyanate, hydroxyacrylate, and cross-linking agent 1, 6-hexanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 18.21g of the dehydrated polyether polyol (Mitsubishi chemical Co., ltd., PTMG 2000), 5.79g of hexamethylene diisocyanate, 0.284g of cross-linking agent 1, 6-hexanediol and 51.40g of hydroxyacrylate (UH-2000 of Japan east Asia Synthesis Co., ltd.) were added together to a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.0g of the mixed material obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.8 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then placing the mixture in a 60 ℃ oven for reaction for 3 days until the binder is solidified, and obtaining the negative electrode dry powder mixture.
Example 4
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymeric binder polymerized from polycarbonate polyol, hexamethylene diisocyanate trimer, hydroxy liquid nitrile rubber, and cross-linking agent 1, 4-butanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 16.62g of the dehydrated polycarbonate polyol (PH-300 from Yu Kogyo Co., ltd.), 7.38g of hexamethylene diisocyanate trimer, 0.198g of cross-linking agent 1, 4-butanediol and 23.69g of hydroxy liquid nitrile rubber (TL 910 from Jining Malus chemical Co., ltd.) were added together to a mixing tank, and mixed for 10 minutes in a defoaming machine at 2000 rpm.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 40 ℃ for reaction for 4 days until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 5
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymeric binder polymerized from polycarbonate polyol, hexamethylene diisocyanate trimer, hydroxy liquid nitrile rubber, and cross-linking agent 1, 4-butanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 18.78g of the dehydrated polycarbonate polyol (Ph-300, kogyo Co., ltd.), 5.22g of hexamethylene diisocyanate trimer, 0.223g of cross-linking agent 1, 4-butanediol and 13.42g of hydroxy liquid nitrile rubber (Jining Malus chemical Co., ltd., TL 910) were added to a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 70 ℃ for reaction for 1 day until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 6
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymer binder polymerized from polyether polyol, trimethylhexamethylene diisocyanate, hydroxyacrylate, and trimethylolpropane as a crosslinking agent as a polymerization monomer.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 18.75g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 5.25g of trimethyl hexamethylene diisocyanate, 0.224g of trimethylolpropane as a crosslinking agent and 15.54g of hydroxyacrylate (OX 7000L of Qingdao trade Co., ltd.) are added together into a mixing tank, and mixed for 10 minutes in a defoaming machine at 2000 rpm.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 45 ℃ for reaction for 5 days until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 7
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymeric binder polymerized from polyether polyol, isophorone diisocyanate, hydroxyacrylate, and trimethylolpropane as a crosslinking agent as a polymerization monomer.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 19.68g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 4.32g of isophorone diisocyanate, 0.243g of trimethylolpropane as a crosslinking agent and 8.11g of hydroxy acrylic ester (OX 7000L of Qingdao trade Co., ltd.) are added together into a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 70 ℃ for reaction for 1 day until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 8
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, the dry electrode binder being a polymer binder polymerized from polyether polyol, trimethylhexamethylene diisocyanate, hydroxyacrylate, and trimethylolpropane as a crosslinking agent as a polymerization monomer.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 20.43g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 3.57g of trimethyl hexamethylene diisocyanate, 0.252g of trimethylolpropane as a crosslinking agent and 8.43g of hydroxy acrylic ester (OX 7000L of Qingdao trade Co., ltd.) are added together into a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 60 ℃ for reaction for 4 days until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 9
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, wherein the dry electrode binder is a polymer binder polymerized by polyether polyol, trimethylhexamethylene diisocyanate, hydroxyacrylate, and crosslinking agent 1, 6-hexanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 19.83g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 4.16g of trimethyl hexamethylene diisocyanate, 0.309g of cross-linking agent 1, 6-hexanediol, 4.09g of hydroxy acrylic ester (Qingdao Ind. Co., ltd. OX 7000L) and 7.09g of hydroxy liquid nitrile rubber (Ji Ning Malus chemical Co., ltd. TL 910) are added into a mixing tank, and mixed for 10min under the condition of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 60 ℃ for reaction for 4 days until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Example 10
In this example, a dry electrode binder, a negative electrode dry powder mixture, and a method of preparing the same are provided, wherein the dry electrode binder is a polymer binder polymerized by polyether polyol, isophorone diisocyanate, hydroxyacrylate, and crosslinking agent 1, 6-hexanediol as polymerization monomers.
The preparation method of the negative electrode dry powder mixture comprises the following steps:
(1) 19.68g of dehydrated polyether polyol (Pasteur, polytetrahydrofuran ether PTMG 3000), 4.32g of isophorone diisocyanate, 0.307g of crosslinking agent 1, 6-hexanediol and 8.11g of hydroxy acrylic ester (Qingdao Co., ltd. OX 7000L) are added together into a mixing tank, and mixed for 10 minutes in a state of 2000rpm in a defoaming machine.
(2) 1.6g of the mixture obtained in the step (1) was taken out, added to a mixture of graphite and conductive carbon (18.2 g of graphite, 0.2g of conductive carbon), and mixed in a defoaming machine at 2000rpm for 10min. And then standing at 70 ℃ for reaction for 1 day until the binder is solidified, so as to obtain the negative electrode dry powder mixture.
Comparative example 1
The only difference from example 1 is that the hydroxy acrylate was replaced with hydroxy terminated polybutadiene (hydroxy terminated polybutadiene type I of Technophores, inc.).
Comparative example 2
The only difference from example 2 is that the hydroxy acrylate was replaced with hydroxy terminated polybutadiene (hydroxy terminated polybutadiene type I of Technophores, inc.).
Comparative example 3
The only difference from example 1 is that no hydroxy liquid nitrile rubber was added in the preparation of the negative electrode dry powder mixture, and the rest was the same as in example 1.
Application examples 1-10 and comparative application examples 1-3
The preparation process of the dry electrode negative electrode plate comprises the following steps:
the negative electrode dry powder mixture prepared as above was ground with an agate mortar, and then coated on a current collector copper foil by a dry method, and hot rolled at 60 ℃ to obtain the dry electrode negative electrode sheets of application examples 1 to 10 and comparative application examples 1 to 3.
The preparation method of the lithium ion battery comprises the following steps:
the dry electrode negative electrode pieces of application examples 1-10 and the dry electrode negative electrode pieces of comparative application examples 1-3 are respectively assembled with lithium metal electrode pieces to form a lithium ion button cell, and the LiPF is used for preparing the lithium ion button cell 6 Dissolving in electrolyte of EC/DEC/EMC=2:3:1 according to the concentration of 1mol/L, and after the electricity-buckling assembly is completed, testing the first-time charging specific capacity, the first-time discharging specific capacity, the first-time effect and the like according to the following steps: standing for 2h; constant current discharge: 0.1C to 0.005V;0.08C to 0.001V;0.05C to 0.001V;0.02C to 0.001V; standing for 10min; constant current charging: 0.1C to 1.5V.
The first charge specific capacity, the first discharge specific capacity, and the first effect test results are shown in table 1.
TABLE 1
Figure BDA0004061070430000191
As can be seen from the data in Table 1, in the buckling test of the dry electrode sheet prepared from the negative electrode dry powder mixture, the capacity (the first-time charging specific capacity is more than 370mAh/g, and the first-time discharging specific capacity is more than 395 mAh/g) and the first effect (more than 95%) can reach relatively high values.
The negative electrode dry powder mixtures used in comparative application examples 1 and 2 were prepared by substituting hydroxyl acrylate with hydroxyl-terminated polybutadiene, and the modified polyurethane dry electrode binder prepared from polybutadiene was poor in strength and toughness, resulting in poor toughness and strength of the prepared dry electrode sheet, and after multiple charging and discharging, the binder could not cope with the volume change of the negative electrode, resulting in partial graphite falling off and thus deterioration of the battery performance, thus resulting in significant reduction of both charge gram capacity and discharge specific capacity and initial efficiency of the prepared lithium ion button battery.
The negative electrode dry powder mixture used in comparative application example 3 was prepared without using a hydroxyacrylate resin and a hydroxylbutyronitrile rubber, and since the hydroxyacrylate resin and the hydroxylbutyronitrile rubber were not used, the electrolyte resistance of the binder was poor, resulting in that the electrode sheet could not be maintained stable for a long period of time during charge and discharge, and thus the performance of the battery was poor, thus resulting in a significant decrease in both the charge gram capacity and the discharge specific capacity as well as the initial efficiency of the prepared lithium ion button cell.
The applicant states that the dry electrode binder, the negative electrode dry powder mixture and the use thereof of the present invention are illustrated by the above examples, but the present invention is not limited to the above examples, i.e. it is not meant that the present invention must be practiced in dependence on the above examples. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims (10)

1. The dry electrode binder is characterized in that the dry electrode binder is a polymer binder, and polymerization monomers of the polymer binder comprise isocyanate monomers, polyol monomers, other hydroxyl-containing monomers and cross-linking agent monomers, wherein the other hydroxyl-containing monomers are at least one of hydroxyl acrylate resins or hydroxyl liquid nitrile rubber.
2. The dry electrode binder of claim 1 wherein the isocyanate monomer comprises any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2, 4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4' -dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 1, 4-benzene diisocyanate, or norbornane diisocyanate;
Preferably, the polyol monomers comprise any one or a combination of at least two of polyester polyols or polyether polyols;
preferably, the polyester polyol comprises a polycarbonate polyol;
preferably, the hydroxyl acrylate resin has a number average molecular weight of 500 to 3000;
preferably, the hydroxy acrylate resin comprises any one or a combination of at least two of styrene, acrylic acid, butyl acrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate or hydroxypropyl acrylate;
preferably, the cross-linking agent monomer comprises any one or a combination of at least two of dihydric alcohol cross-linking agent, trihydric alcohol cross-linking agent, diamine cross-linking agent, alcohol amine cross-linking agent, alicyclic alcohol cross-linking agent, aromatic alcohol cross-linking agent, glycerin allyl ether, glycidyl allyl ether or dicumyl peroxide;
preferably, the glycol cross-linking agent comprises any one or a combination of at least two of 1, 4-butanediol, ethylene glycol, propylene glycol, diethylene glycol or neopentyl glycol;
preferably, the triol crosslinking agent comprises glycerol and/or trimethylolpropane;
Preferably, the diamine cross-linking agent comprises any one or a combination of at least two of 3, 3-dichloro-4, 4-diaminodiphenylmethane, 3, 5-dimethylthiotoluenediamine, 3, 5-diethyltoluenediamine, 2, 4-diamino-3, 5-dimethylthiochlorobenzene or isophorone diamine;
preferably, the alcohol amine cross-linking agent comprises any one or a combination of at least two of ethanolamine, diethanolamine, triethanolamine or N, N-bis (2-hydroxypropyl) aniline;
preferably, the alicyclic alcohol cross-linking agent comprises 1, 4-cyclohexanediol and/or hydrogenated bisphenol A;
preferably, the aromatic alcohol crosslinking agent comprises any one or a combination of at least two of dimethylene phenyl glycol, hydroquinone bis-beta-hydroxyethyl ether or resorcinol hydroxyl ether;
preferably, the number average molecular weight of the dry electrode binder is 30000-80000.
3. A negative electrode dry powder mixture, characterized in that the negative electrode dry powder mixture comprises an active material, a conductive agent, and the dry electrode binder according to claim 1 or 2, the dry electrode binder being coated on the surfaces of the active material and the conductive agent.
4. The negative electrode dry powder mixture according to claim 3, wherein the dry electrode binder is obtained by in-situ polymerization on the surfaces of an active material and a conductive agent;
Preferably, the active material comprises one or a combination of at least two of graphite, silicon-based oxide, silicon carbon material, lithium titanate, graphene or tin-based composite oxide, preferably graphite;
preferably, the graphite comprises one or a combination of at least two of natural graphite, artificial graphite, amorphous carbon, or mesophase carbon microbeads;
preferably, the conductive agent comprises one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes or conductive carbon black;
preferably, the weight percentage of active substances in the anode dry powder mixture is 93% -98.5%, the weight percentage of dry electrode binder is 1% -5%, and the weight percentage of conductive agent is 0.5% -2%.
5. The method for preparing a negative electrode dry powder mixture according to claim 3 or 4, characterized in that the method comprises the steps of:
mixing a polymerization monomer, mixing the polymerization monomer with an active substance and a conductive agent, and carrying out in-situ polymerization to obtain the negative electrode dry powder mixture, wherein the polymerization monomer comprises isocyanate monomer, polyalcohol monomer, other hydroxyl-containing monomers and cross-linking agent monomer, and the other hydroxyl-containing monomers are at least one of hydroxyl acrylate resin or hydroxyl liquid nitrile rubber.
6. The method according to claim 5, wherein the isocyanate monomer comprises any one or a combination of at least two of toluene diisocyanate, diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, dimethylbiphenyl diisocyanate, hexamethylene diisocyanate biuret, hexamethylene diisocyanate trimer, 2, 4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4' -dicyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, 1, 4-benzene diisocyanate, or norbornane diisocyanate;
preferably, the polyol monomers comprise any one or a combination of at least two of polyester polyols or polyether polyols;
preferably, the polyester polyol comprises a polycarbonate polyol;
preferably, the hydroxyl acrylate resin has a number average molecular weight of 500 to 3000;
preferably, the hydroxy acrylate resin comprises any one or a combination of at least two of styrene, acrylic acid, butyl acrylate, butyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate or hydroxypropyl acrylate;
Preferably, the polymerized monomer is a polymerized monomer subjected to water removal treatment;
preferably, the molar ratio of isocyanate groups in the isocyanate monomer to hydroxyl groups in the polyol monomer is 1.2:1 to 4:1;
preferably, the molar ratio of isocyanate groups in the isocyanate monomer to hydroxyl groups in other hydroxyl-containing monomers is 1.2:1-12:1;
preferably, the cross-linking agent monomer comprises any one or a combination of at least two of dihydric alcohol cross-linking agent, trihydric alcohol cross-linking agent, diamine cross-linking agent, alcohol amine cross-linking agent, alicyclic alcohol cross-linking agent, aromatic alcohol cross-linking agent, glycerin allyl ether, glycidyl allyl ether or dicumyl peroxide;
preferably, the glycol cross-linking agent comprises any one or a combination of at least two of 1, 4-butanediol, ethylene glycol, propylene glycol, diethylene glycol or neopentyl glycol;
preferably, the triol crosslinking agent comprises glycerol and/or trimethylolpropane;
preferably, the diamine cross-linking agent comprises any one or a combination of at least two of 3, 3-dichloro-4, 4-diaminodiphenylmethane, 3, 5-dimethylthiotoluenediamine, 3, 5-diethyltoluenediamine, 2, 4-diamino-3, 5-dimethylthiochlorobenzene or isophorone diamine;
Preferably, the alcohol amine cross-linking agent comprises any one or a combination of at least two of ethanolamine, diethanolamine, triethanolamine or N, N-bis (2-hydroxypropyl) aniline;
preferably, the cycloaliphatic alcohol cross-linking agent comprises 1, 4-cyclohexanediol and/or hydrogenated bisphenol a.
Preferably, the aromatic alcohol crosslinking agent comprises any one or a combination of at least two of dimethylene phenyl glycol, hydroquinone bis-beta-hydroxyethyl ether or resorcinol hydroxyl ether;
preferably, the molar ratio of isocyanate groups in the isocyanate monomer to reactive groups in the crosslinker is from 1.3:1 to 12:1.
7. The method of preparation according to claim 5 or 6, wherein the active substance comprises one or a combination of at least two of graphite, silicon-based oxide, silicon-carbon material, lithium titanate, graphene or tin-based composite oxide, preferably graphite;
preferably, the graphite comprises one or a combination of at least two of natural graphite, artificial graphite, amorphous carbon, or mesophase carbon microbeads;
preferably, the conductive agent comprises one or a combination of at least two of conductive graphite, acetylene black, carbon nanotubes or conductive carbon black;
Preferably, the in situ polymerization temperature is 25-80 ℃;
preferably, the in situ polymerization is carried out for a period of 1 to 7 days.
8. A dry electrode negative electrode comprising the negative electrode dry powder mixture of claim 3 or 4.
9. The method for producing a dry electrode negative electrode according to claim 8, characterized in that the method for producing comprises: hot rolling the negative electrode dry powder mixture of claim 3 or 4 into a self-supporting film or directly hot rolling onto a current collector to form a dry electrode negative electrode;
preferably, the negative electrode dry powder mixture is subjected to grinding before hot rolling;
preferably, the temperature of the hot roll is in the range of 25-120 ℃.
10. An electrochemical energy storage device comprising the dry electrode anode of claim 9;
preferably, the electrochemical energy storage device is selected from one of a lithium ion battery, a sodium ion battery, a supercapacitor, a fuel cell or a solar cell.
CN202310059894.0A 2023-01-17 2023-01-17 Dry electrode binder, negative electrode dry powder mixture and application thereof Pending CN116314792A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117327460A (en) * 2023-12-01 2024-01-02 四川新能源汽车创新中心有限公司 Adhesive, pole piece, electrolyte membrane for lithium ion battery and preparation method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117327460A (en) * 2023-12-01 2024-01-02 四川新能源汽车创新中心有限公司 Adhesive, pole piece, electrolyte membrane for lithium ion battery and preparation method

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