Temperature-resistant low-permeability lithium battery diaphragm and preparation method thereof
阅读说明：本技术 一种耐温低透气锂电池隔膜及其制备方法 (Temperature-resistant low-permeability lithium battery diaphragm and preparation method thereof ) 是由 张立斌 沈亚定 于 2021-07-13 设计创作，主要内容包括：本发明公开了一种耐温低透气锂电池隔膜及其制备方法,包括基膜,以及基膜表面涂覆的耐温浆料；所述基膜为聚乙烯隔膜、聚丙烯隔膜、无纺布、聚丙烯/聚乙烯复合隔膜中的一种；所述耐温浆料由第一分散液和第二分散液混合而成。本申请加入了自制的聚苯胺,聚苯胺是一种常见的高分子化合物,具有一定的绝缘性能,在正常的电化学制备过程中,将其与质子酸进行掺杂能够使其变为具有导电性能的材料,而在本申请中电池薄膜需要具有一定的绝缘性和耐热性,因此本申请不对其进行掺杂,保证隔膜的正常使用并且,能够保证在复杂的化学环境下能够维持稳定,在电解液中能够稳定存在,因此,聚苯胺的加入能够保证产品膜的化学稳定性的效果。(The invention discloses a temperature-resistant low-permeability lithium battery diaphragm and a preparation method thereof, wherein the lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film; the base membrane is one of a polyethylene diaphragm, a polypropylene diaphragm, non-woven fabric and a polypropylene/polyethylene composite diaphragm; the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid. Self-made polyaniline has been added to this application, polyaniline is a common macromolecular compound, certain insulating properties has, in normal electrochemistry preparation process, dope it with protonic acid and can make it become to have the material of conductivity, and the battery film need have certain insulating nature and heat resistance in this application, consequently, this application does not dope it, guarantee the normal use of diaphragm and, can guarantee to maintain stably under complicated chemical environment, can exist steadily in electrolyte, consequently, the effect of the chemical stability of product membrane can be guaranteed in the joining of polyaniline.)
1. A temperature-resistant low-permeability lithium battery diaphragm is characterized in that: the battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base membrane is one of a polyethylene diaphragm, a polypropylene diaphragm, non-woven fabric and a polypropylene/polyethylene composite diaphragm;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
2. The temperature-resistant low-permeability lithium battery separator according to claim 1, wherein: the temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 0.1-3%.
3. The temperature-resistant low-permeability lithium battery separator according to claim 2, wherein: the wetting agent comprises one or more of polyether organic silicon, ethanol, n-butanol and alkynol polymer.
4. The temperature-resistant low-permeability lithium battery separator according to claim 1, wherein: the first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 0.1-10%, the mass ratio of the dispersing agent to the ceramic powder is 0.1-10%, and the solid content of the first dispersion liquid is 30-80%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 0.1-20%.
5. The temperature-resistant low-permeability lithium battery separator according to claim 4, wherein: the temperature-resistant adhesive comprises one or more of polyacrylic acid, polyacrylate, polyacrylonitrile, polyacrylamide and polyvinylidene fluoride;
the dispersant comprises one or a mixture of polyacrylate and ammonium polyacrylate;
the high-viscosity binder comprises one or more of polyacrylic acid, polyacrylate, polyacrylonitrile, polyacrylamide and polyvinylidene fluoride;
the ceramic powder comprises one or more of aluminum oxide, silicon oxide, boehmite and magnesium hydroxide;
the high viscosity binder also includes a mix.
6. The temperature-resistant low-permeability lithium battery separator according to claim 5, wherein: the mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of the aniline to the ammonium persulfate is 1.5-1.8: 1.
7. A preparation method of a temperature-resistant low-permeability lithium battery diaphragm is characterized by comprising the following steps: the steps are as follows,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water to prepare a second dispersion liquid;
s3, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent to prepare temperature-resistant slurry;
s4, coating separator:
and coating the sizing agent on the base film, and drying to obtain the temperature-resistant low-permeability coating diaphragm.
8. The method for preparing a temperature-resistant low-permeability lithium battery diaphragm according to claim 7, which is characterized in that: the specific steps are as follows,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 1-30 m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 1-30 m/s for 5-120min to prepare a second dispersion liquid;
s3, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 1-10 m/s for 5-60min to prepare temperature-resistant slurry;
s4, coating separator:
coating the slurry on a base film, and drying at 40-90 deg.C for 1-100s to obtain the temperature-resistant low-permeability coating membrane.
9. The method for preparing a temperature-resistant low-permeability lithium battery diaphragm according to claim 8, characterized in that: the preparation steps of the mixture are as follows:
s1, dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 12-13h, filtering, and drying at 185 ℃ to obtain a master batch;
s2, recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating to 8-10 ℃, reacting for 10-12h, heating to 20-25 ℃, adding iron powder, heating under reflux at 95-100 ℃, reacting for 3-4h, filtering, adding sodium pyrosulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A;
s3, adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to the temperature of 100-105 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
Technical Field
The invention relates to the technical field of battery films, in particular to a temperature-resistant low-permeability lithium battery diaphragm and a preparation method thereof.
Background
The diaphragm is one of four main materials of the lithium ion battery, and the demand of the diaphragm is increasing along with the wider application of the lithium ion battery. The market puts more and more strict requirements on the safety of lithium ion batteries, which puts higher requirements on the performance of the separator, and the heat resistance is one of important indexes influencing the safety.
The ceramic coating diaphragm is proposed on the market to solve the problem of heat resistance, but the conventional ceramic coating diaphragm is often unsatisfactory in performance under the use condition of more than 150 ℃; ceramic coated separators have also been proposed using temperature resistant adhesives to meet higher temperature resistance, but the increase in permeability of the coating typically exceeds conventional levels, which negatively impacts the rate performance of the cell.
According to the invention, the ceramic coating diaphragm is prepared by compounding the adhesive and the ceramic, so that the diaphragm has the characteristics of high temperature resistance and low air permeability, and the performance of the battery is maintained while the safety is ensured.
Disclosure of Invention
The invention aims to provide a temperature-resistant low-permeability lithium battery diaphragm and a preparation method thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme: a temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base membrane is one of a polyethylene diaphragm, a polypropylene diaphragm, non-woven fabric and a polypropylene/polyethylene composite diaphragm;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
Further, the temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 0.1-3%.
Further, the wetting agent comprises one or more of polyether organic silicon, ethanol, n-butyl alcohol and alkynol polymer.
Further, the first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 0.1-10%, the mass ratio of the dispersing agent to the ceramic powder is 0.1-10%, and the solid content of the first dispersion liquid is 30-80%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 0.1-20%.
Further, the temperature-resistant adhesive comprises one or more of polyacrylic acid, polyacrylate, polyacrylonitrile, polyacrylamide and polyvinylidene fluoride;
the dispersant comprises one or a mixture of polyacrylate and ammonium polyacrylate;
the high-viscosity binder comprises one or more of polyacrylic acid, polyacrylate, polyacrylonitrile, polyacrylamide and polyvinylidene fluoride;
the ceramic powder comprises one or more of aluminum oxide, silicon oxide, boehmite and magnesium hydroxide;
the high viscosity binder also includes a mix.
Further, the mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of the aniline to the ammonium persulfate is 1.5-1.8: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water to prepare a second dispersion liquid;
s3, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent to prepare temperature-resistant slurry;
s4, coating separator:
and coating the sizing agent on the base film, and drying to obtain the temperature-resistant low-permeability coating diaphragm.
Further, the concrete steps are as follows,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 1-30 m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 1-30 m/s for 5-120min to prepare a second dispersion liquid;
s3, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 1-10 m/s for 5-60min to prepare temperature-resistant slurry;
s4, coating separator:
coating the slurry on a base film, and drying at 40-90 deg.C for 1-100s to obtain the temperature-resistant low-permeability coating membrane.
Further, the preparation steps of the mixture are as follows:
s1, dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 12-13h, filtering, and drying at 185 ℃ to obtain a master batch;
according to the method, aniline and ammonium persulfate are used for preparing polyaniline, the aniline is dissolved and cooled in the preparation process, then the aniline is added dropwise, the added ammonium persulfate has certain strong oxidizing property and corrosivity and can be decomposed into oxygen and ozone in a humid environment, so that the molar weight of the aniline and the ammonium persulfate is controlled to be 1.5-1.8:1, the total reaction of the ammonium persulfate can be guaranteed, and further the corrosion of the ammonium persulfate to metals in a lithium battery can be prevented.
S2, recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating to 8-10 ℃, reacting for 10-12h, heating to 20-25 ℃, adding iron powder, heating under reflux at 95-100 ℃, reacting for 3-4h, filtering, adding sodium pyrosulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A;
after the polyaniline is prepared, the polyaniline is heated and dried, the drying temperature needs to be strictly controlled at 185 ℃, the polyaniline can be thermally decomposed at about 300 ℃, the residual aniline can be distilled off by controlling the drying temperature, and then the polyaniline is cooled and recycled, so that the full utilization of the raw materials is ensured.
S3, adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to the temperature of 100-105 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
According to the method, manganese dioxide and sulfuric acid are added into the recovered aniline, a corresponding product tert-butylhydroquinone can be obtained after a series of reactions, and the obtained tert-butylhydroquinone can be used as an excellent antioxidant to play a role, so that the temperature resistance of the product can be ensured.
Compared with the prior art, the invention has the following beneficial effects: the lithium battery thin film is one of the important components of the lithium battery, and the performance of the thin film directly determines the performance of the battery, and has great influence.
This application uses materials such as common polyethylene diaphragm, polypropylene diaphragm, non-woven fabrics, polypropylene/polyethylene composite diaphragm as base film material, and this part of material has excellent temperature resistance. The obtained temperature-resistant adhesive needs to meet the requirements that the molecular weight is more than 1 ten thousand, the Tg is 80-250 ℃, and the viscosity is 10-10000mPa.s, so that a coating temperature-resistant framework formed by the temperature-resistant adhesive and ceramic particles has high temperature resistance, and the size of a diaphragm is maintained in a high-temperature environment.
The deionized water added in the device needs to ensure that the resistivity is more than 0.5M omega cm, so that a pure mixed environment is provided for the temperature-resistant slurry components, and the quality of the diaphragm is further ensured.
The ceramic particles added in the method can form a coating temperature-resistant framework with a temperature-resistant adhesive, and in order to ensure good supporting effect, the method limits ceramic powder,is one or more of aluminum oxide, silicon oxide, boehmite and magnesium hydroxide, and has particle diameter D50 of 0.2-2 μm and specific surface area of 1-40g/m2The shape of the adhesive can be spherical, square, rhombic, dendritic and dumbbell-shaped, and the adhesive can further play a supporting role together with a temperature-resistant adhesive.
The wetting agent is added, the wetting agent can improve the wettability of the slurry, but the addition amount of the wetting agent needs to be limited, the optimal wetting agent/temperature-resistant slurry mass ratio is limited to be 0.1-3%, the solid content of the prepared temperature-resistant slurry can be guaranteed to be 10-60%, the viscosity of the prepared temperature-resistant slurry is 10-500mPa.s, the surface tension of the prepared temperature-resistant slurry is less than 35mN/m, and the quality of a diaphragm product can be further guaranteed.
The self-made polyaniline is added, the polyaniline is a common high molecular compound and has certain insulating property, the polyaniline and protonic acid are doped in the normal electrochemical preparation process to enable the polyaniline to become a material with conductive property, and the battery film needs to have certain insulating property and heat resistance in the application, so that the self-made polyaniline is not doped in the application, and the normal use of the diaphragm is ensured. The polyaniline is added, on one hand, the preparation process is simple, the polyaniline can be stably maintained in a complex chemical environment and can stably exist in electrolyte, and therefore, the chemical stability of a product film can be guaranteed due to the addition of the polyaniline.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is a polyethylene diaphragm;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 0.1%.
The wetting agent includes polyether silicones.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 0.1%, the mass ratio of the dispersing agent to the ceramic powder is 0.1-10%, and the solid content of the first dispersion liquid is 30%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 0.1%.
The temperature-resistant adhesive comprises polyacrylic acid;
the dispersant comprises a polyacrylate;
the high viscosity binder comprises polyacrylic acid;
the ceramic powder comprises aluminum oxide;
a method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 1m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 1m/s for 5min to prepare a second dispersion liquid;
s3, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 1m/s for 5min to prepare temperature-resistant slurry;
s4, coating separator:
and coating the slurry on a base film, and drying at 40 ℃ for 1s to obtain the temperature-resistant low-permeability coating diaphragm.
Example 2
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is a polypropylene diaphragm;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 0.1%.
The wetting agent comprises ethanol.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 0.1%, the mass ratio of the dispersing agent to the ceramic powder is 0.1%, and the solid content of the first dispersion liquid is 30%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 0.1%.
The temperature-resistant adhesive comprises polyacrylate;
the dispersant comprises ammonium polyacrylate;
the high viscosity binder comprises a polyacrylate;
the ceramic powder comprises silicon oxide;
the high viscosity binder also includes a mix.
The mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of aniline to ammonium persulfate is 1.5: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 1m/s for 5min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 1m/s for 5min to prepare a second dispersion liquid;
s3, preparing a mixture:
1. dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 12h, filtering, and drying at 185 ℃ to obtain a master batch;
2. recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating at the temperature of 8 ℃, reacting for 10 hours, heating at the temperature of 20 ℃, adding iron powder, performing reflux heating at the temperature of 95 ℃, reacting for 3 hours, filtering, adding sodium metabisulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A;
3. adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to 100 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
S4, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 1m/s for 5min to prepare temperature-resistant slurry;
s5, coating separator:
and coating the slurry on a base film, and drying at 40 ℃ for 1s to obtain the temperature-resistant low-permeability coating diaphragm.
Example 3
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is non-woven fabric;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 1.2%.
The wetting agent comprises n-butanol.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 1.2%, the mass ratio of the dispersing agent to the ceramic powder is 0.1-10%, and the solid content of the first dispersion liquid is 50%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 10%.
The temperature-resistant adhesive comprises polyacrylate;
the dispersant comprises a polyacrylate;
the high-viscosity binder comprises polyacrylonitrile;
the ceramic powder comprises boehmite;
the high viscosity binder also includes a mix.
The mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of aniline to ammonium persulfate is 1.6: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 1-30 m/s for 90min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 20m/s for 90min to prepare a second dispersion liquid;
s3, preparing a mixture:
1. dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 12.5h, filtering, and drying at 185 ℃ to obtain a master batch;
2. recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating to 24 ℃, adding iron powder, performing reflux heating to 97 ℃, reacting for 3.5 hours, filtering, adding sodium metabisulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A, wherein the temperature of the distillate is 9 ℃, the reaction time is 11 hours, and the temperature of the reaction is 24 ℃;
3. adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to 102 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
S4, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 5m/s for 31min to prepare temperature-resistant slurry;
s5, coating separator:
and coating the slurry on a base film, and drying at the drying temperature of 70 ℃ for 75s to obtain the temperature-resistant low-permeability coating diaphragm.
Example 4
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is one of polypropylene/polyethylene composite diaphragms;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 3%.
The wetting agent includes an acetylenic alcohol polymer.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 10%, the mass ratio of the dispersing agent to the ceramic powder is 10%, and the solid content of the first dispersion liquid is 80%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 20%.
The temperature-resistant adhesive comprises polyvinylidene fluoride;
the dispersant comprises a polyacrylate;
the high viscosity binder comprises polyacrylamide;
the ceramic powder comprises magnesium hydroxide;
the high viscosity binder also includes a mix.
The mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of aniline to ammonium persulfate is 1.8: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 30m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 30m/s for 120min to prepare a second dispersion liquid;
s3, preparing a mixture:
1. dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 13h, filtering, and drying at 185 ℃ to obtain a master batch;
2. recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating at 20-25 ℃, adding iron powder, heating under reflux at 100 ℃ for 4h, filtering, adding sodium metabisulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A, wherein the temperature of the distillate is 10 ℃, the reaction time is 12h, and the temperature of the reaction is 20-25 ℃;
3. adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to 105 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
S4, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 10m/s for 5-60min to prepare temperature-resistant slurry;
s5, coating separator:
and coating the slurry on a base film, and drying at 90 ℃ for 100s to obtain the temperature-resistant low-permeability coating diaphragm.
Comparative example 1
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is one of polypropylene/polyethylene composite diaphragms;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 3%.
The wetting agent includes an acetylenic alcohol polymer.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 10%, the mass ratio of the dispersing agent to the ceramic powder is 10%, and the solid content of the first dispersion liquid is 80%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 20%.
The temperature-resistant adhesive comprises polyvinylidene fluoride;
the dispersant comprises a polyacrylate;
the high viscosity binder comprises polyacrylamide;
the ceramic powder comprises magnesium hydroxide;
the high viscosity binder also includes a mix.
The mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of aniline to ammonium persulfate is 1.8: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 30m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 30m/s for 120min to prepare a second dispersion liquid;
s3, preparing a mixture:
1. dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 13h, filtering, and drying at 185 ℃ to obtain a master batch;
2. recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating at 20-25 ℃, adding iron powder, heating under reflux at 100 ℃ for 4h, filtering, adding sodium metabisulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A, wherein the temperature of the distillate is 10 ℃, the reaction time is 12h, and the temperature of the reaction is 20-25 ℃;
3. adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to 105 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
S4, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 10m/s for 5-60min to prepare temperature-resistant slurry;
s5, coating separator:
and coating the slurry on a base film, and drying at 90 ℃ for 100s to obtain the temperature-resistant low-permeability coating diaphragm.
Comparative example 2
A temperature-resistant low-permeability lithium battery diaphragm comprises a base film and temperature-resistant slurry coated on the surface of the base film;
the base film is one of polypropylene/polyethylene composite diaphragms;
the temperature-resistant slurry is formed by mixing a first dispersion liquid and a second dispersion liquid.
The temperature-resistant slurry also comprises a wetting agent;
the mass ratio of the wetting agent to the temperature-resistant slurry is 3%.
The wetting agent includes an acetylenic alcohol polymer.
The first dispersion liquid is prepared from a temperature-resistant binder, ceramic powder, a dispersing agent and deionized water;
the second dispersion liquid is prepared from a high-viscosity adhesive and deionized water;
the mass ratio of the temperature-resistant adhesive to the ceramic powder in the first dispersion liquid is 10%, the mass ratio of the dispersing agent to the ceramic powder is 10%, and the solid content of the first dispersion liquid is 80%;
the mass ratio of the high-viscosity adhesive molecules in the second dispersion liquid to the temperature-resistant adhesive molecules is 20%.
The temperature-resistant adhesive comprises polyvinylidene fluoride;
the dispersant comprises a polyacrylate;
the high viscosity binder comprises polyacrylamide;
the ceramic powder comprises magnesium hydroxide;
the high viscosity binder also includes a mix.
The mixture is prepared from aniline, ammonium persulfate, phosphoric acid, manganese dioxide, toluene, a solvent, sodium metabisulfite, zinc powder and sulfuric acid;
the molar ratio of aniline to ammonium persulfate is 1.8: 1.
A method for preparing a temperature-resistant low-permeability lithium battery diaphragm comprises the following steps,
s1, preparation of a first dispersion:
mixing and dispersing a temperature-resistant adhesive, deionized water, ceramic powder and a dispersing agent at a dispersion linear speed of 30m/s for 5-180min to obtain a first dispersion liquid;
s2, preparation of a second dispersion:
mixing and dispersing the high-viscosity adhesive and deionized water at a dispersion linear speed of 30m/s for 120min to prepare a second dispersion liquid;
s3, preparing a mixture:
1. dissolving aniline, stirring, adding ammonium persulfate, stirring and heating, heating at constant temperature for 13h, filtering, and drying at 185 ℃ to obtain a master batch;
2. recovering distillate in the drying process, cooling, adding manganese dioxide and sulfuric acid, stirring, cooling, heating at 20-25 ℃, adding iron powder, heating under reflux at 100 ℃ for 4h, filtering, adding sodium metabisulfite and zinc powder, heating, filtering, cooling and isolating to obtain a product A, wherein the temperature of the distillate is 10 ℃, the reaction time is 12h, and the temperature of the reaction is 20-25 ℃;
3. adding toluene and phosphoric acid into the obtained product A, uniformly mixing, adding a solvent, heating to 105 ℃ to obtain a product B, and mixing the obtained product B with the master batch to obtain a mixture.
S4, preparing temperature-resistant slurry:
mixing and dispersing the first dispersion liquid, the second dispersion liquid and a wetting agent at a dispersion linear speed of 10m/s for 5-60min to prepare temperature-resistant slurry;
s5, coating separator:
and coating the slurry on a base film, and drying at 90 ℃ for 100s to obtain the temperature-resistant low-permeability coating diaphragm.
Experiment of
And (3) setting a comparative example 1 and a comparative example 2 by taking the example 4 as a control, wherein the aniline is not recovered in the comparative example 1, and the molar ratio of the aniline to the ammonium persulfate in the comparative example 2 is 1: 1, control experiments were performed.
The products of example 1, example 2, example 3, example 4, comparative example 1, and comparative example 2 were subjected to component content tests, and the results were as follows,
experimental group
Example 1
Example 2
Example 3
Example 4
Comparative example 1
Comparative example 2
Aniline
----
Not detected out
Not detected out
Not detected out
Not detected out
Not detected out
Ammonium persulfate
----
Not detected out
Not detected out
Not testedGo out
----
Not detected out
Watch 1
The products of example 1, example 2, example 3, example 4, comparative example 1, comparative example 2 were tested and the results were as follows,
experimental group
Thickness of basal lamina (mum)
Coating thickness (μm)
Shrinkage (180 ℃/1h)
Coating ventilation (s/mum)
Example 1
9
4
6
＜5％
Example 2
9
4
＜5％
＜20
Example 3
9
4
＜5％
＜20
Example 4
9
4
＜5％
＜20
Comparative example 1
9
4
7
＜20
Comparative example 2
9
4
6
＜20
Watch two
The products of example 1, example 2, example 3, example 4, comparative example 1, comparative example 2 were subjected to a chemical resistance test (soaking in strong acid, strong base for 100 hours), and as a result,
experiment ofGroup of
Example 1
Example 2
Example 3
Example 4
Comparative example 1
Comparative example 2
Chemical resistance
Surface exfoliation
Without change
Without change
Without change
Without change
Without change
Watch III
As can be seen from table one, in comparative example 1, aniline was not recovered, but aniline was not detected in the product film because aniline was volatilized during the drying of polyaniline, and thus aniline was not contained in the product film, but in the test, the test environment was examined to find the presence of aniline. In comparative example 2 the molar ratio of aniline to ammonium persulfate was 1: according to the normal experimental rule, a small amount of aniline and ammonium persulfate still can be contained in the product and do not react to generate surplus, but aniline and ammonium persulfate are not found in the product analysis and determination, the fact that aniline can escape in the polyaniline drying process can be known in the comparative example 1, and for ammonium persulfate, the environment is detected in the experiment process to find the generation of ozone, and the fact that ammonium sulfate is decomposed can be judged.
As can be seen from table two, the heat shrinkage of comparative example 1 is larger in examples 1, 2, 3, 4, 1 and 2 under the same thickness of the base film and the same thickness of the coating, and next, examples 1 and 2 illustrate that the heat resistance of the product can be improved by the tert-butyl hydroquinone obtained by recycling distilled aniline in examples 2, 3 and 4, and further, the heat resistance of the product film can be ensured.
Table three shows that the product films of example 1, example 2, example 3, example 4, comparative example 1, and comparative example 2 have surface peeling in example 1 under 100h soaking in strong acid and strong base, which indicates that the polyaniline added in example 2, example 3, and example 4, and comparative example 1 and comparative example 2 of the present application has certain stability in strong acid and strong base environment.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
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