CN111816826A

CN111816826A - Aqueous polymer functional slurry and preparation method and application thereof

Info

Publication number: CN111816826A
Application number: CN202010720452.2A
Authority: CN
Inventors: 张海明; 林妙云; 邱钧锋; 李越旺
Original assignee: Foshan Jinhui Gao Ke Photoelectric Material Ltd By Share Ltd
Current assignee: Henan Huiqiang New Energy Material Technology Co ltd
Priority date: 2020-07-24
Filing date: 2020-07-24
Publication date: 2020-10-23
Anticipated expiration: 2040-07-24
Also published as: WO2022016630A1; CN111816826B

Abstract

The invention relates to a preparation method of aqueous polymer functional slurry and a preparation method and application thereof. The preparation method comprises the following steps: mixing 30-60% of a high polymer material, 1-5% of a deflocculation type aqueous dispersant of a specific kind and 78-70% of water I35 to prepare dispersed slurry; mixing 39.9% -78.5% of dispersion pulp, 0.1% -1.5% of a specific type of volume steric hindrance type aqueous dispersant and 20% -60% of grinding medium, and grinding to prepare grinding pulp; 30 to 80 percent of grinding slurry, 0.1 to 0.5 percent of wetting agent, 0.5 to 2.5 percent of binder and 17 to 69.4 percent of water are mixed to prepare aqueous polymer functional slurry with good storage stability, strong binding power and good wettability and liquid retention, and the aqueous polymer functional slurry can be coated on a diaphragm of a lithium ion battery. The preparation method has simple process flow and low cost, can realize continuous production, and is suitable for large-scale production.

Description

Aqueous polymer functional slurry and preparation method and application thereof

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to aqueous high polymer functional slurry as well as a preparation method and application thereof.

Background

With the increasing energy crisis and the environmental pollution, the new energy industry which is vigorously developed to be green and environment-friendly has become the mainstream consensus in the world. China is a large automobile consumption country, the development of new energy automobiles is the most important direction for the development of new energy industry in China, and the development of new energy automobiles is also a necessary way for turning the large automobile country into a strong automobile country. At present, the important factor for limiting the development of new energy automobiles is the vehicle-mounted power lithium battery.

Generally, a lithium ion battery is mainly composed of four key components, namely a positive electrode, a negative electrode, a separator and an electrolyte. The separator is mainly used for preventing the positive electrode and the negative electrode in the battery from contacting to cause short circuit, and simultaneously providing a transmission channel of lithium ions between the positive electrode and the negative electrode. Although the diaphragm is not an active component of the lithium ion battery, the quality of the diaphragm directly influences the performance of the whole lithium ion battery, such as internal resistance, capacity, cycle life, safety and the like. Polyolefin is the most widely applied material in the field of lithium battery diaphragms, but the polyolefin diaphragm also has the defects of low heat-resistant stability, poor wettability to electrolyte and the like, thereby influencing the capacity, cycle life, rate charge and discharge and safety performance of the lithium battery.

At present, the development research on improving the performance of the polyolefin lithium battery separator is mainly to improve the surface property of the separator, and the main research direction for improving the surface property of the separator is to perform coating treatment on the separator. The design and preparation of the functional slurry for coating the diaphragm are key factors for determining the quality of the coated diaphragm, and the coated diaphragm coated by the functional slurry with good performance can effectively improve the comprehensive performance of the lithium battery. After the diaphragm is coated with the ceramic functional slurry, the heat shrinkage resistance of the diaphragm can be effectively improved, and the safety and the thermal stability of the battery are further improved. After the gel functional slurry is coated, the liquid retention performance of the diaphragm and the pole piece bonding performance can be obviously improved. Mastering the preparation technology and the coating technology of the functional coating slurry of the lithium battery diaphragm plays an important role in improving the overall competitiveness of the self-developed lithium ion battery diaphragm and improving the structure of an industrial chain.

Nowadays, there are two main types of functional slurry applied to coating of lithium battery separators: one is coating slurry taking inorganic materials as functional components, and the form of aqueous slurry is more; the other type is coating slurry taking organic macromolecules as functional components, and the type is oily slurry. Wherein, the inorganic functional components are ceramic powder such as alumina, boehmite, magnesium oxide and the like, and the main function of the inorganic functional components is to improve the thermal stability of the polyolefin diaphragm; the organic functional components comprise high-molecular polymers such as PMMA (polymethyl methacrylate), PVDF (polyvinylidene fluoride), PVDH-HPF (polyvinylidene fluoride-hexafluoropropylene copolymer), aramid fiber and the like, different functional components are selected to prepare different functional slurry, and the lithium battery diaphragms with different functions are obtained after coating. The organic functional polymer coating diaphragm has good wettability and liquid retention to electrolyte, can effectively bond the diaphragm and a pole piece, increases the cycle performance of the battery, and obviously improves the safety of the battery.

The existing lithium ion battery organic functional polymer coating diaphragm is generally coated by oily functional slurry, although the oily functional slurry has better coating cohesiveness, the phenomena of hole blocking and poor ventilation are easy to occur, and N-methyl pyrrolidone, dimethylacetamide, acetone and the like are mostly adopted as organic solvents in the slurry, so that the cost is high, the environmental pollution is large, the health of operators is also injured, and the coating becomes an unsafe factor in the slurry production and use processes.

In recent years, aqueous organic polymer functional slurry is a research focus, and compared with oily functional slurry, aqueous slurry adopts water as a solvent, and has the advantages of low production cost, small environmental pollution and the like; however, the aqueous polymer functional slurry obtained by adopting the conventional formula design and preparation process has the problems of poor storage performance, short shelf life and the like of a slurry system; and the aqueous polymer functional slurry uses more wetting dispersant, so that the bonding property is weakened, and the battery core prepared by coating the diaphragm has the problems of softness, poor hot-pressing bonding property with a pole piece and the like. Therefore, research and optimization of the formula design and preparation process of the aqueous polymer functional slurry are needed, the stability of the slurry is improved, and the binding power is improved.

Disclosure of Invention

Based on the above, the invention aims to provide a preparation method of aqueous polymer functional slurry with simple process and high production efficiency, and the prepared aqueous polymer functional slurry has excellent storage stability, excellent quality stability, good wettability and liquid retention on electrolyte, strong bonding force with a pole piece and greatly improved safety, and can be used for coating a lithium battery diaphragm.

The technical scheme is as follows:

a preparation method of aqueous polymer functional slurry comprises the following steps:

mixing a high polymer material, a deflocculation type aqueous dispersant and water I to prepare dispersed slurry;

mixing the dispersion slurry, the volume steric hindrance type aqueous dispersant and a grinding medium, and grinding to prepare grinding slurry;

mixing the grinding, slurry wetting agent, binder and water II to prepare aqueous high-molecular functional slurry;

the high polymer material, the deflocculating aqueous dispersant and the water I respectively account for 30-60 percent, 1-5 percent and 35-70 percent of the dispersing pulp by mass percent;

the dispersion slurry, the volume steric hindrance type water-based dispersant and the grinding medium account for the grinding slurry in percentage by mass respectively as follows: 39.9% -78.5%, 0.1% -1.5% and 20% -60%;

the grinding slurry, the wetting agent, the binder and the water II account for the aqueous polymer functional slurry in percentage by mass respectively as follows: 30% -80%, 0.1% -0.5%, 0.5% -2.5% and 17% -69.4%;

the deflocculating aqueous dispersant is selected from one or more of polyacrylate and phosphate;

the volume-hindered aqueous dispersant is selected from one or more of block copolymer of polyurethane and copolymer of polyacrylate.

In one embodiment, the copolymer of polyacrylate is a terpolymer of polyacrylate.

In one embodiment, the copolymer of polyacrylate is a hydrophobically modified polyacrylate copolymer.

In one embodiment, the mass percentages of the polymer material, the deflocculating aqueous dispersant and the water I in the dispersed slurry are 40-45%, 1-5% and 50-55%, respectively.

In one embodiment, the mass percentages of the dispersion slurry, the volume-hindered aqueous dispersant and the grinding medium in the grinding slurry are respectively: 40% -50%, 0.8% -1.0% and 49% -59.2%.

In one embodiment, the mass percentages of the grinding slurry, the wetting agent, the binder and the water II in the aqueous polymer functional slurry are respectively: 40% -50%, 0.2% -0.3%, 0.8% -1.2% and 48.5% -59%.

In one embodiment, the polymer material is selected from one or more of polytetrafluoroethylene, polyvinylidene fluoride homopolymer, polyvinylidene fluoride copolymer, polymethyl methacrylate homopolymer, polymethyl methacrylate copolymer, aqueous polyimide, aramid, and polyethylene oxide.

In one embodiment, the polymer material is selected from one or two of polyvinylidene fluoride homopolymer and polyvinylidene fluoride copolymer synthesized by emulsion polymerization.

In one embodiment, the deflocculating aqueous dispersant is selected from one or more of polyacrylate and phosphate.

In one embodiment, the water I is ultrapure water; under the condition of 25 ℃, the resistivity of the water I is 5M omega cm-15M omega cm, and the pH value is 6.0-8.0.

In one embodiment, the dispersion slurry is prepared under stirring, and the process parameters are as follows:

the rotating speed is 1000r/min-2500r/min, the time is 20min-40min, and the temperature is 20 ℃ to 60 ℃.

In one embodiment, the process parameters for preparing the dispersion slurry are as follows:

the rotating speed is 1800r/min-2000r/min, the time is 25min-30min, and the temperature is 25 ℃ to 30 ℃.

In one embodiment, in the step of preparing the dispersed slurry, a specific feeding sequence is selected, and the feeding sequence comprises part of water I, the deflocculation type aqueous dispersant, the high polymer material and the balance of water I.

In one embodiment, the volume-hindered aqueous dispersant is selected from one or two of bentonite and hydrophobically modified polyacrylic copolymer.

In one embodiment, the grinding media are selected from one or more of glass beads, alumina grinding balls, zirconia beads, yttrium stabilized zirconia beads, cerium zirconia beads.

In one embodiment, the grinding media have a particle size of 0.5mm to 10 mm.

In one embodiment, the grinding media is selected from one of zirconia beads and cerium stabilized zirconia beads, and has a particle size of 0.5mm to 10 mm.

In one embodiment, the slurry is prepared under stirring, and the process parameters are as follows:

the rotating speed is 800r/min-2000r/min, the time is 30min-240min, and the temperature is 10 ℃ to 40 ℃.

In one embodiment, the process parameters for preparing the slurry are as follows:

the rotating speed is 1200r/min-1500r/min, the time is 60min-120min, and the temperature is 15 ℃ to 20 ℃.

In one embodiment, in the step of preparing the grinding slurry, a specific feeding sequence is adopted, and the feeding sequence comprises the grinding medium, the dispersing slurry and the volume-hindered aqueous dispersant.

In one embodiment, the wetting agent is selected from one or more of alkyl sulfate, polyoxyethylene alkylphenol ether, polyoxyethylene fatty alcohol ether and polyether modified polydimethylsiloxane.

In one embodiment, the adhesive is selected from one or more of waterborne polyurethane, waterborne epoxy resin and waterborne polymethyl acrylate adhesives.

In one embodiment, the water II is ultrapure water; under the condition of 25 ℃, the resistivity of the water II is more than 10M omega cm, and the pH value is 6.5-7.0.

In one embodiment, the aqueous polymer functional slurry is prepared under stirring, and the process parameters are as follows:

the rotating speed is 200r/min-500r/min, the time is 10min-40min, and the temperature is 20 ℃ to 30 ℃.

In one embodiment, the process parameters for preparing the aqueous polymer functional slurry are as follows:

the rotating speed is 300r/min-350r/min, the time is 20min-30min, and the temperature is 20 ℃ to 30 ℃.

In one embodiment, in the step of preparing the aqueous functional polymer slurry, a specific feeding sequence is adopted, and the feeding sequence is grinding slurry, wetting agent, adhesive and water II.

The invention also provides the aqueous polymer functional slurry prepared by the preparation method of the aqueous polymer functional slurry.

The invention also provides application of the aqueous polymer functional slurry in preparation of a modified lithium battery diaphragm.

Compared with the prior art, the invention has the following beneficial effects:

the preparation method of the aqueous polymer functional slurry provided by the invention comprises the following steps: mixing a certain amount of high polymer material, a deflocculation type aqueous dispersant and water I to prepare dispersed slurry; mixing the dispersion slurry with a volume steric hindrance type aqueous dispersant and a grinding medium to prepare grinding slurry; and mixing the grinding slurry with a wetting agent, a binder and water II to prepare the aqueous high-molecular functional slurry.

Wherein, water is used as a dispersion medium, and repulsion among polymer material particles is larger than attraction under the action of the deflocculation type aqueous dispersant, so that the polymer material particles are in a deflocculated state and are better dispersed in water to prepare uniform dispersed slurry which is convenient for subsequent operation. After the dispersing slurry, the amphiphilic volume-hindered aqueous dispersant and the grinding medium are mixed and ground, the particle size of the dispersing slurry particles is reduced, the particles are easier to agglomerate while the particle size is reduced, and the dispersing slurry particles are separated by providing a frame/steric hindrance structure through the volume-hindered aqueous dispersant to obtain uniform, stable and high-solid-content grinding slurry. Finally, the grinding slurry is mixed with a wetting agent, a binder and water, the water is used as a dispersing medium and a diluting agent, the surface tension of the slurry and the water is reduced under the action of the wetting agent, the slurry is uniformly dispersed in the water, and the grinding slurry is diluted, so that the water-based high-molecular functional slurry has good wettability and liquid retention property, storage stability and quality stability; the adhesive has the function of enhancing the adhesive force, so that the aqueous polymer functional slurry has excellent adhesive force, is not easy to fall off after being adhered with a pole piece, and ensures the performance of the battery.

Therefore, the invention can prepare the aqueous polymer functional slurry with excellent storage stability, quality stability and strong bonding capability by using less aqueous auxiliary agent through a three-stage preparation process. The coating is coated on a diaphragm of a lithium ion battery, has strong bonding capability, high cell hardness and excellent hot-press bonding performance with a pole piece, and can obviously improve the comprehensive performance of the lithium ion battery.

In addition, the preparation method provided by the invention has the advantages of simple process flow, low cost, continuous production and suitability for large-scale production.

Drawings

FIG. 1 shows the effects of day 1, day 7, day 14 and day 28 of storing the aqueous polymeric functional slurries of comparative example 1, comparative example 2, examples 1, 2, 3, 4 in a 100mL plastic bottle;

FIG. 2 shows the effect of the aqueous polymeric functional slurries of examples 5 to 6 and comparative examples 3 to 6 after day 1 when stored in a 100mL plastic bottle.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The existing aqueous polymer functional slurry has the problems of poor storage performance, short shelf life and the like of a slurry system; and the aqueous polymer functional slurry uses more wetting dispersant, so that the bonding property is weakened, and the battery core prepared by coating the diaphragm has the problems of softness, poor hot-pressing bonding property with a pole piece and the like.

Aiming at the problems, the invention provides a preparation method of aqueous polymer functional slurry with simple process and high production efficiency, and the prepared aqueous polymer functional slurry has excellent storage stability, excellent quality stability, good wettability and liquid retention on electrolyte, strong bonding force with a pole piece and greatly improved safety, and can be used for coating a lithium battery diaphragm.

The technical scheme is as follows:

mixing the dispersion slurry with a volume steric hindrance type aqueous dispersant and a grinding medium, and grinding to prepare grinding slurry;

mixing the grinding slurry with a wetting agent, a binder and water II to prepare aqueous high-molecular functional slurry;

wherein the high polymer material, the deflocculating aqueous dispersant and the water I respectively account for 30-60 percent, 1-5 percent and 35-70 percent of the dispersed pulp by mass percent;

the volume-hindered aqueous dispersant is selected from one or more of block copolymer of polyurethane and polyacrylate copolymer.

The water is used as a dispersing medium, and the repulsion among the polymer material particles is larger than the attraction under the action of the deflocculation type water-based dispersing agent, so that the polymer material particles are in a deflocculated state and are better dispersed in the water to prepare uniform dispersed slurry which is convenient for subsequent operation. After the dispersing slurry, the amphiphilic volume-hindered aqueous dispersant and the grinding medium are mixed and ground, the particle size of the dispersing slurry particles is reduced, the particles are easier to agglomerate while the particle size is reduced, and the dispersing slurry particles are separated by providing a frame/steric hindrance structure through the volume-hindered aqueous dispersant to obtain uniform, stable and high-solid-content grinding slurry. Finally, the grinding slurry is mixed with a wetting agent, a binder and water, the water is used as a dispersing medium and a diluting agent, the surface tension of the slurry and the water is reduced under the action of the wetting agent, the slurry is uniformly dispersed in the water, and the grinding slurry is diluted, so that the water-based high-molecular functional slurry has good wettability and liquid retention property, storage stability and quality stability; the adhesive has the function of enhancing the adhesive force, so that the aqueous polymer functional slurry has excellent adhesive force, is not easy to fall off after being adhered with a pole piece, and ensures the performance of the battery.

(1) Preferably, the step of mixing the polymer material, the deflocculating aqueous dispersant and the water I to prepare the dispersion slurry comprises the following steps:

adding 30-60% of high polymer material, 1-5% of deflocculation type aqueous dispersant and 35-70% of water into a movable cylinder with a cooling water jacket under the stirring state of a high-speed dispersion machine, and dispersing to prepare dispersed slurry.

In one preferable embodiment, the mass percentages of the polymer material, the deflocculating aqueous dispersant and the water I in the dispersing pulp are respectively 40-45%, 1-5% and 50-55%.

In one preferred embodiment, the polymer material is selected from one or two of polyvinylidene fluoride homopolymer and polyvinylidene fluoride copolymer synthesized by emulsion polymerization.

More preferably, the melting point of the polyvinylidene fluoride homopolymer is 150-170 ℃, the primary particle size is 90-120 nm, and the secondary particle size is 10-20 μm. The melting point of the polyvinylidene fluoride copolymer is 90-160 ℃, the primary particle size is 100-200 nm, and the secondary particle size is 10-20 μm.

The deflocculating aqueous dispersant is selected from one or more of polyacrylate and phosphate. The polyacrylate comprises one or more of polymethyl methacrylate, polyethyl methacrylate and polypropylene methacrylate. The phosphate ester comprises one or more of triethyl phosphate, styrene-based polyether phosphate, fatty alcohol ether phosphate and nonyl phenol polyether phosphate.

In one preferred embodiment, the resistivity of the water I is more than 10M Ω -cm and the pH value is 6.5-7.0 at 25 ℃.

In one embodiment, the preparation of the dispersion slurry is carried out under stirring, and the process parameters are as follows:

In one preferred embodiment, the process parameters for preparing the dispersion slurry are as follows:

In one preferred embodiment, in the step of preparing the dispersed slurry, a specific feeding sequence is selected, and the feeding sequence sequentially comprises part of water I, the deflocculation type aqueous dispersant, the high polymer material and the balance of water I. Preferably, the part of water I is 50% -70% of water I, and the rest of water I is 30% -50% of water I.

According to the designed raw material proportion, 50% -70% of water I, deflocculation type aqueous dispersant, high polymer material and 30% -50% of water I are sequentially added into a moving cylinder with a cooling water jacket under the stirring state of a high-speed disperser, and dispersed to prepare dispersed slurry. Wherein the stirrer is a high-speed dispersion machine, the dispersion disc is a tooth-shaped dispersion disc, the rotating speed is 1000r/min-2500r/min, the time is 20min-40min, and the temperature is 20 ℃ to 60 ℃.

(2) Mixing the dispersion slurry with a volume steric hindrance type aqueous dispersant and a grinding medium, and grinding to prepare the grinding slurry, wherein the step of preparing the grinding slurry comprises the following steps:

adding 39.9-78.5% of the dispersion slurry, 20-60% of grinding medium and 0.1-1.5% of volume steric type aqueous dispersant into a sand mill, grinding, filtering and preparing the grinding slurry.

In one preferred embodiment, the mass percentages of the dispersion slurry, the volume-hindered aqueous dispersant and the grinding medium in the grinding slurry are respectively: 40% -50%, 0.8% -1.0% and 49% -59.2%.

The terpolymer of polyacrylate means that other monomers are introduced to polymerize in addition to the acryl-based monomer, and the terpolymer means that three monomer units such as acrylic acid-ethylene-styrene are copolymerized. Hydrophobic modification refers to the introduction of a hydrophobic-R (such as alkane, phenyl, etc.) segment into the carboxyl-COOH group in acrylic acid through esterification and other reactions (such as glycidyl polymerization with aliphatic alcohol R-OH).

Preferably, the sterically hindered aqueous dispersant is selected from hydrophobically modified polyacrylic acid copolymers.

In one embodiment, the grinding media have a particle size of 0.5mm to 10 mm.

In one preferred embodiment, the grinding medium is selected from one of zirconia beads and cerium stabilized zirconia beads, and the particle size is 0.5mm to 10 mm.

In one embodiment, the preparation of the slurry is performed under stirring, and the process parameters are as follows:

In one preferred embodiment, the process parameters for preparing the slurry are as follows:

Preferably, the dispersing slurry is mixed with a volume-steric type aqueous dispersant and a grinding medium, and grinding is carried out, wherein the steps for preparing the grinding slurry are as follows:

the grinding medium is weighed in advance and added into a grinding machine, then the dispersion slurry is pumped into the sand grinding machine through a diaphragm pump, after grinding for a certain time, the volume steric hindrance type aqueous dispersant is added, grinding is carried out under a certain grinding process, and filtering is carried out to prepare the grinding slurry. Wherein the sand mill is a horizontal sand mill with a cooling water jacket, the rotating speed of the mill is 1200r/min-1500r/min, the time is 60min-120min, and the temperature is 15 ℃ to 20 ℃.

(3) Mixing the grinding slurry with a wetting agent, a binder and water II to prepare the aqueous polymer functional slurry, wherein the step of preparing the aqueous polymer functional slurry comprises the following steps:

adding 30-80% of grinding slurry, 0.1-0.5% of wetting agent, 0.5-2.5% of binder and 0.5-69.4% of water II17 into a stirrer in sequence, and uniformly stirring to obtain the finished slurry of the water-based functional slurry.

In one preferred embodiment, the mass percentages of the grinding slurry, the wetting agent, the binder and the water II in the aqueous polymer functional slurry are respectively: 40% -50%, 0.2% -0.3%, 0.8% -1.2% and 48.5% -59%.

In one embodiment, the adhesive is selected from one or more of waterborne polyurethane, waterborne epoxy resin and waterborne polyacrylate adhesives. The waterborne polyurethane binder comprises polyurethane emulsion, vinyl polyurethane emulsion, polyisocyanate emulsion and closed polyurethane emulsion; the waterborne epoxy resin binder comprises CYWD series waterborne epoxy resin CYDW-100 and CYDW-100P, CTDW-120 of the petrochemical division of the Zhongpetrochemical Baling; the aqueous polyacrylate adhesive comprises methyl alpha-cyanoacrylate and isopropyl alpha-cyanoacrylate. Preferably, the adhesive is selected from methyl alpha-cyanoacrylate and/or isopropyl alpha-cyanoacrylate.

In one embodiment, the preparation of the aqueous polymer functional slurry is performed under stirring, and the process parameters are as follows:

Preferably, the step of mixing the grinding slurry with a wetting agent, a binder and water II to prepare the aqueous polymer functional slurry is as follows:

and (3) adding the grinding slurry, the wetting agent, the binder and the water II in turn under stirring of a stirrer, and uniformly stirring to prepare the finished slurry of the water-based functional slurry. Wherein, the mixer is the dispenser of taking spiral shell formula or butterfly stirring vane, and the mixer sets up: 200r/min-500r/min, 10min-40min and 20-30 ℃.

The following are specific examples.

The deflocculated polyacrylate aqueous dispersant in examples 1 to 5 and comparative examples 3, 5 and 6 described below refers to polymethyl methacrylate, and the deflocculated polyacrylate aqueous dispersant in example 6 refers to polyethyl methacrylate.

The polyacrylate terpolymer in the following examples and comparative examples refers to a terpolymer consisting of polyacrylic acid-polyethylene-polystyrene. The hydrophobic modified polyacrylate copolymer refers to a copolymer consisting of polyacrylic acid-polybutadiene, and the hydrophobic modification refers to esterification reaction between carboxyl in acrylic acid and butanol.

Example 1

The embodiment provides a preparation method of aqueous polymer functional slurry, and a preparation method and application thereof.

(1) Preparing dispersion slurry: and sequentially adding 38kg of ultrapure water, 40kg of polyvinylidene fluoride copolymer powder, 2kg of deflocculated polyacrylate water-based dispersing agent and 20kg of ultrapure water into a dispersing agent matched production cylinder, wherein the dispersing speed is set to 2000r/min, the dispersing time is 25min, and the temperature is controlled to be 20-30 ℃ to prepare the dispersing pulp.

(2) Preparing grinding slurry: 24.5kg of cerium-stabilized zirconia beads (with the particle size of 0.8-1.2mm) are put into a cavity of a grinding machine, 25kg of the dispersed slurry prepared in the step (1) and 0.5kg of the volume-hindered polyacrylate terpolymer aqueous dispersant are pumped by a diaphragm pump, the rotation speed of the grinding machine is 1500r/min, the temperature is controlled at 15-20 ℃, and the grinding time is 120min, so that the grinding slurry is prepared.

(3) Preparing finished pulp: and (3) sequentially adding 25kg of the grinding slurry prepared in the step (2), 0.15kg of polyether modified polydimethylsiloxane wetting agent, 0.6kg of polyacrylate adhesive and 24.25kg of ultrapure water into a production cylinder matched with a stirring machine, wherein the rotating speed of the stirring machine is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished product of the aqueous high-molecular functional slurry 1.

Coating a diaphragm with finished slurry: and coating a 2-micron water-based PVDF coating on the 9+ 3-micron ceramic diaphragm in a gravure roller coating mode, and baking in an oven to obtain the water-based functional coating diaphragm.

Example 2

(1) Preparing dispersion slurry: 31kg of ultrapure water, 45kg of polyvinylidene fluoride copolymer powder, 4kg of deflocculated polyacrylate water-based dispersing agent and 20kg of ultrapure water are sequentially added into a production cylinder matched with the dispersing agent, the dispersing speed is set to 2000r/min, the dispersing time is 25min, and the temperature is controlled to be 20-30 ℃ to prepare the dispersing slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of polyacrylate adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished product of the aqueous high-molecular functional slurry 2.

Example 3

(1) Preparing dispersion slurry: 31kg of ultrapure water, 45kg of polyvinylidene fluoride homopolymer powder, 4kg of deflocculated polyacrylate aqueous dispersant and 20kg of ultrapure water are sequentially added into a production cylinder matched with the dispersant, the dispersion speed is set to 2000r/min, the dispersion time is 25min, and the temperature is controlled to be 20-30 ℃ to prepare the dispersion slurry.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium-stabilized zirconia beads (the particle size is 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of volume-hindered polyacrylate terpolymer aqueous dispersing agent by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1200r/min, controlling the temperature at 15-20 ℃, and grinding for 60min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of aqueous epoxy resin adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished aqueous high-molecular functional slurry 3.

Example 4

(1) Preparing dispersion slurry: 31kg of ultrapure water, 45kg of polyvinylidene fluoride copolymer powder, 4kg of triethyl phosphate aqueous dispersant and 20kg of ultrapure water are sequentially added into a production cylinder matched with the dispersant, the dispersion speed is 1800r/min, the dispersion time is 30min, and the temperature is controlled at 20-30 ℃ to prepare dispersion slurry.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium-stabilized zirconia beads (with the particle size of 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of hydrophobic modified polyacrylate copolymer aqueous dispersant by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1500r/min, controlling the temperature at 15-20 ℃, and grinding for 120min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of polyurethane adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished product of the aqueous high-molecular functional slurry 4.

Example 5

The embodiment provides a preparation method of aqueous polymer functional slurry, and a preparation method and application thereof. Basically the same as example 3, except that the hydrophobic modified polyacrylate copolymer was used as the volume-hindered aqueous dispersant.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium-stabilized zirconia beads (the particle size is 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of the volume-hindered hydrophobic modified polyacrylate copolymer aqueous dispersant by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1200r/min, controlling the temperature at 15-20 ℃, and grinding for 60min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of aqueous epoxy resin adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished aqueous high-molecular functional slurry 5.

Example 6

(1) Preparing dispersion slurry: adding 32kg of ultrapure water, 34kg of polyvinylidene fluoride copolymer powder, 1kg of deflocculated fatty acid polyethylene glycol ester aqueous dispersant and 33kg of ultrapure water into a production cylinder matched with the dispersant in sequence, wherein the dispersion speed is set to 1200r/min, the dispersion time is 20min, and the temperature is controlled to be 40-50 ℃ to prepare dispersion slurry.

(2) Preparing grinding slurry: 20kg of glass beads (with the particle size of 0.8-1.2mm) are put into a cavity of a grinding machine, 40kg of the dispersed slurry prepared in the step (1) and 0.4kg of carboxymethyl cellulose aqueous dispersant are pumped by a diaphragm pump, the rotation speed of the grinding machine is 1000r/min, the temperature is controlled at 15-20 ℃, and the grinding time is 120min, so that the grinding slurry is prepared.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of alkyl sulfate, 0.4kg of polyurethane adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃, so as to prepare the finished product of the aqueous polymer functional slurry 6.

Comparative example 1

The aqueous polymer functional slurry used in the comparative example is commercially available aqueous polyvinylidene fluoride functional slurry J04-001 for coating the lithium ion battery separator.

Coating a separator: and coating a 2-micron aqueous polyvinylidene fluoride coating on the 9+ 3-micron ceramic coated diaphragm in a gravure roller coating mode, and baking in an oven to obtain the aqueous functional coated diaphragm.

Comparative example 2

The aqueous functional slurry is prepared according to an aqueous polyvinylidene fluoride slurry formula which is mainstream in the industry, and the formula comprises the following components: 66.2 percent of ultrapure water, 28 percent of polyvinylidene fluoride powder, 4.2 percent of dispersant BYK-LPC22136,0.5 percent of defoaming agent BYK-1785, 0.5 percent of wetting agent BYK-LPX20990 and 0.6 percent of anti-settling agent LAPONITE RD.

The method comprises the following steps: firstly adding ultrapure water, adding a dispersing agent and an anti-settling agent under a stirring state, dispersing for 30min at 1500rpm, then adding polyvinylidene fluoride powder, adjusting the rotating speed to 800-1000rpm, adding a defoaming agent and a wetting agent, and dispersing for 30min to obtain slurry.

Comparative example 3

The comparative example provides a preparation method of aqueous polymer functional slurry, and a preparation method and application thereof. Substantially in accordance with example 5, except that this comparative example adds the volume-hindered aqueous dispersant in the first step and adds the deflocculated aqueous dispersant in the second step.

(1) Preparing dispersion slurry: 31kg of ultrapure water, 45kg of polyvinylidene fluoride homopolymer powder, 4kg of volume-hindered hydrophobic modified polyacrylate copolymer aqueous dispersant and 20kg of ultrapure water are sequentially added into a production cylinder matched with the dispersant, the dispersion speed is set to 2000r/min, the dispersion time is 25min, the temperature is controlled at 20-30 ℃, and the dispersion slurry is prepared.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium stabilized zirconia beads (with the particle size of 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of deflocculated polyacrylate aqueous dispersant by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1200r/min, controlling the temperature at 15-20 ℃, and grinding for 60min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of aqueous epoxy resin adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished aqueous high-molecular functional slurry 7.

Comparative example 4

The comparative example provides a preparation method of aqueous polymer functional slurry, and a preparation method and application thereof. Substantially in accordance with example 5, except that this comparative example selected a fatty acid polyglycol ester aqueous dispersant as the deflocculating aqueous dispersant.

(1) Preparing dispersion slurry: 31kg of ultrapure water, 45kg of polyvinylidene fluoride homopolymer powder, 4kg of deflocculated fatty acid polyethylene glycol ester aqueous dispersant and 20kg of ultrapure water are sequentially added into a production cylinder matched with the dispersant, the dispersion speed is set to 2000r/min, the dispersion time is 25min, and the temperature is controlled to be 20-30 ℃ to prepare the dispersion slurry.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium-stabilized zirconia beads (with the particle size of 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of hydrophobic modified polyacrylate copolymer aqueous dispersant by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1200r/min, controlling the temperature at 15-20 ℃, and grinding for 60min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of aqueous epoxy resin adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished aqueous high-molecular functional slurry 8.

Comparative example 5

The comparative example provides a preparation method of aqueous polymer functional slurry, and a preparation method and application thereof. Substantially in accordance with example 5, except that this comparative example selects a carboxymethyl cellulose aqueous dispersant as the volume-hindered aqueous dispersant.

(2) Preparing grinding slurry: and (2) putting 29.6kg of cerium stabilized zirconia beads (with the particle size of 0.8-1.2mm) into a cavity of a grinding machine, pumping 20kg of the dispersed slurry prepared in the step (1) and 0.4kg of carboxymethyl cellulose aqueous dispersing agent by using a diaphragm pump, controlling the rotation speed of the grinding machine at 1200r/min, controlling the temperature at 15-20 ℃, and grinding for 60min to prepare the grinding slurry.

(3) Preparing finished pulp: and (3) sequentially adding 20kg of the grinding slurry prepared in the step (2), 0.1kg of polyether modified polydimethylsiloxane wetting agent, 0.4kg of polyurethane adhesive and 29.5kg of ultrapure water into a production cylinder matched with a stirrer, wherein the rotating speed of the stirrer is 350r/min, the stirring is carried out for 20min, and the temperature is controlled to be 20-30 ℃ to prepare the finished product of the aqueous high-molecular functional slurry 9.

Comparative example 6

The aqueous functional slurry is prepared according to the preparation method of the aqueous polyvinylidene fluoride slurry which is mainstream in the industry, and the formula components are as follows: 33.58kg of ultrapure water, 3.6kg of polyvinylidene fluoride copolymer powder, 0.32kg of deflocculated polyacrylate aqueous dispersing agent, 11.84kg of cerium stabilized zirconia beads, 0.16kg of hydrophobic modified polyacrylate copolymer aqueous dispersing agent, 0.1kg of polyether modified polydimethylsiloxane wetting agent and 0.4kg of polyurethane adhesive.

The preparation method comprises the following steps: firstly, adding cerium-stabilized zirconia beads into a dispersion basket of a basket type dispersion machine, then adding ultrapure water, adding a deflocculating polyacrylate water-based dispersing agent and an anti-settling agent under a stirring state, dispersing for 10min at 1500rpm, then adding polyvinylidene fluoride powder, a hydrophobic modified polyacrylate copolymer, a polyether modified polydimethylsiloxane wetting agent and a polyurethane adhesive, adjusting the rotating speed to 800 plus 1000rpm, and dispersing for 30min to obtain slurry.

Test example 1

And (3) carrying out performance test on the aqueous polymer functional slurry obtained in the examples 1-6 and the comparative examples 1-6.

(1) And (3) storage stability of the slurry: the finished slurry was stored in 100ml plastic bottles at 25 ℃ and the slurry was observed for delamination and settling. The results are shown in FIGS. 1-2. Wherein, for convenience, the products of examples 1 to 6 are represented by numerals 1 to 6, the product of comparative example 1 is represented by the abbreviation J04-001, the product of comparative example 2 is represented by BYK, and the products of comparative examples 3 to 6 are represented by numerals 7 to 10.

FIGS. 1(a) -1(d) show the cases of day 1, day 7, day 14 and day 28 when the aqueous polymer functional slurries of comparative example 1, comparative example 2, examples 1, 2, 3 and 4 (from left to right) were stored in 100mL plastic bottles. Comparative examples 1, 2 and examples 1-4 showed no significant delamination and settling in the plastic bottles after day 1 of storage. After 7 days of storage, the slurry of comparative example 1 has obvious demixing and precipitation phenomena, and the slurry of comparative example 2 and examples 1-4 has good stability and no obvious demixing and precipitation phenomena. After 14 days of storage, the stratified precipitation of comparative example 1 was intensified and the upper layer liquid was clear; comparative example 2 began to exhibit bottom delamination, and examples 1-4 had good slurry stability and no significant delamination. After 28 days of storage, comparative example 1 completely separated into two layers, a distinct sediment layer also appeared at the bottom of comparative example 2, and a slightly clear liquid layer began to appear at the top of examples 1-4, giving good overall stability to the slurry. As is clear from fig. 1, the aqueous functional polymer slurries prepared in examples 1 to 4 of the present invention have excellent storage stability, compared to comparative examples 1 to 2.

FIG. 2 shows the aqueous polymer functional pastes of examples 5 to 6 and comparative examples 3 to 6 (from left to right) after day 1 when they were stored in a 100mL plastic bottle. As is clear from fig. 2, the aqueous polymer functional slurries of examples 5 to 6 according to the present invention have excellent storage stability, and the aqueous polymer functional slurry of comparative example 3 had hard precipitates at the bottom layer and turbid liquid at the upper layer; the aqueous polymer functional slurry of comparative example 4 has a delamination phenomenon, the upper layer is clear and the lower layer is turbid; the aqueous polymer functional slurry of comparative example 5 was severely settled; the aqueous polymer functional slurry of comparative example 6 had a hard precipitate at the bottom and a turbid supernatant.

(2) Surface tension test: the test is carried out according to the national standard GB/T30693-2014 measurement of the contact angle between the plastic film and the water. The results are shown in Table 1:

TABLE 1

Test example 2

(1) Basic performance test of water-based functional slurry coated separator

The basic performance data of the water-based functional slurry coating membrane such as thickness, ventilation value, area density, thermal shrinkage, peel strength and the like are tested by referring to a national standard GBT36363-2018 or an enterprise standard test method.

The results of testing the aqueous polymer functional slurry-coated separators of examples 1 to 6 and comparative examples 1 to 2 are shown in table 2:

TABLE 2

Note: the aqueous polymer functional slurries of comparative examples 3 to 6 were not used for coating separators because they had poor stability, generated significant sedimentation after 1 day of storage, did not meet the industrial standards, had low production efficiency, and had poor coating quality stability.

As can be seen from table 2, the lithium ion battery separators with aqueous functional coatings prepared in examples 1 to 6 of the present invention are superior to those of comparative examples 1 to 2 in terms of thickness increase, air permeability, electrolyte absorption rate, peel strength, etc., when coated with the same ceramic film.

(2) The method for testing the basic performance of the water-based functional coating diaphragm after being wound around the battery cell comprises the following steps:

a: and the dry pressing refers to winding the positive plate, the water-based functional coating diaphragm and the negative plate, placing the wound positive plate, water-based functional coating diaphragm and negative plate into an aluminum-plastic film, packaging the aluminum-plastic film, hot-pressing the aluminum-plastic film for 30 minutes at 65 ℃ and under the pressure of 1MPa, and testing the hardness of the battery cell and the cohesive force of the plate after cooling.

b: wet-pressing finger-pulp positive plate and water-based functional coating separatorAfter the film and the negative plate are wound, the film is placed in an aluminum plastic film, and 9g of 1mol/L LiPF is injected firstly₆And (3) packaging the electrolyte (the solvent is ethylene carbonate, diethyl carbonate and methyl ethyl carbonate in a volume ratio of 1:1:1), hot-pressing for 30 minutes at 65 ℃ and under the pressure of 1MPa, and testing the hardness of the battery cell and the bonding force of the pole piece after cooling.

c: the cell hardness test is to apply 1kg of force to press down the cell by using a round-head needle with the diameter of 1mm, measure the indentation depth value, and the larger the value is, the softer the cell is, otherwise, the smaller the value is, the harder the cell is.

After examples 1-6 and comparative examples 1-2 were coated with the aqueous functional slurry to form a soft-pack cell with specification 506090, the test results are shown in table 3:

TABLE 3

As can be seen from Table 3, the soft-packaged cell prepared from the lithium ion battery separator with the aqueous functional coating prepared in examples 1-6 of the invention is superior to comparative examples 1-2 in terms of cell hardness, pole piece adhesion, internal resistance, capacity, rate, and 60 ℃ retention rate after 7-day high-temperature storage.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The preparation method of the aqueous polymer functional slurry is characterized by comprising the following steps:

mixing the grinding slurry, a wetting agent, a binder and water II to prepare aqueous high-molecular functional slurry;

2. The preparation method of the aqueous polymer functional slurry according to claim 1, wherein the polymer material, the deflocculating aqueous dispersant and the water I account for 40-45%, 1-5% and 50-55% of the dispersed slurry by mass respectively.

3. The method for preparing aqueous polymer functional slurry according to claim 1, wherein the dispersing slurry, the volume-hindered aqueous dispersant and the grinding medium respectively account for the following components in percentage by mass: 40% -50%, 0.8% -1.0% and 49% -59.2%.

4. The method for preparing aqueous functional polymer slurry according to claim 1, wherein the grinding slurry, the wetting agent, the binder and the water II account for the aqueous functional polymer slurry in percentage by mass: 40% -50%, 0.2% -0.3%, 0.8% -1.2% and 48.5% -59%.

5. The method for preparing aqueous functional polymer slurry according to any one of claims 1 to 4, wherein the polymer material is selected from one or more of polytetrafluoroethylene, polyvinylidene fluoride homopolymer, polyvinylidene fluoride copolymer, polymethyl methacrylate homopolymer, polymethyl methacrylate copolymer, aqueous polyimide, aramid, and polyethylene oxide.

6. The method for preparing aqueous functional polymer slurry according to any one of claims 1 to 4, wherein the grinding medium is one or more selected from glass beads, alumina grinding balls, zirconia beads, yttrium-stabilized zirconia beads, cerium-zirconia beads; and/or the presence of a catalyst in the reaction mixture,

the particle size of the grinding medium is 0.5mm-10 mm.

7. The method for preparing aqueous functional polymer slurry according to any one of claims 1 to 4, wherein the wetting agent is selected from one or more of alkyl sulfate, polyoxyethylene alkylphenol ether, polyoxyethylene fatty alcohol ether, and polyether-modified polydimethylsiloxane; and/or the presence of a catalyst in the reaction mixture,

the adhesive is selected from one or more of waterborne polyurethane, waterborne epoxy resin and waterborne polyacrylate adhesive; and/or the presence of a catalyst in the reaction mixture,

the water I and the water II are both ultrapure water; under the condition of 25 ℃, the resistivity of the water I is 5 MOmega cm-15 MOmega cm, and the pH value is 6.0-8.0; the resistivity of the water II is more than 10M omega cm, and the pH value is 6.5-7.0.

8. The method for preparing aqueous functional polymer slurry according to any one of claims 1 to 4, wherein the dispersed slurry is prepared under stirring, and the process parameters are as follows:

the rotating speed is 1000r/min-2500r/min, the time is 20min-40min, and the temperature is 20 ℃ to 60 ℃; and/or the presence of a catalyst in the reaction mixture,

the grinding slurry is prepared under the stirring state, and the technological parameters are as follows:

the rotating speed is 800r/min-2000r/min, the time is 30min-240min, and the temperature is 10 ℃ to 40 ℃; and/or the presence of a catalyst in the reaction mixture,

the aqueous polymer functional slurry is prepared under a stirring state, and the process parameters are as follows:

9. An aqueous functional polymer slurry prepared by the method according to any one of claims 1 to 8.

10. Use of the aqueous polymer functional slurry according to claim 9 for preparing a modified lithium battery separator.