阅读说明：本技术 一种无纺纸离子电池隔膜及其制备方法 (Nonwoven paper ion battery diaphragm and preparation method thereof ) 是由 田子钦 崔泽君 陈加强 赵艳 袁子丹 黄恒辉 谢嘉宜 徐睿杰 雷彩红 于 2019-10-14 设计创作，主要内容包括：本发明属于离子电池的技术领域,尤其涉及一种无纺纸离子电池隔膜及其制备方法。本发明提供了一种无纺纸离子电池隔膜的制备方法,包括以下步骤：步骤1、将改性钛酸钡粉末与有机溶液混合,得到涂覆浆料；步骤2、将所述涂覆浆料涂覆在无纺纸的表面,热压后制得无纺纸离子电池隔膜,将钛酸钡进行改性,提高钛酸钡的阻燃效果,在有机溶液的作用下,提高了改性的钛酸钡粉末的相容性,改性的钛酸钡粉末的粒径可以是单一粒径,也可以是不同的粒径,通过热压的处理,将涂覆浆料嵌入无纺纸的微孔中,从而降低无纺纸的微孔孔径,控制无纺纸的孔径大小、厚度大小以及解决锂枝晶的问题,解决现有的无纺纸的孔径和厚度过大,无法应用在离子电池的技术缺陷。(The invention belongs to the technical field of ion batteries, and particularly relates to a nonwoven paper ion battery diaphragm and a preparation method thereof. The invention provides a preparation method of a non-woven paper ion battery diaphragm, which comprises the following steps: step 1, mixing modified barium titanate powder with an organic solution to obtain a coating slurry; and 2, coating the coating slurry on the surface of non-woven paper, carrying out hot pressing to obtain a non-woven paper ion battery diaphragm, modifying barium titanate to improve the flame retardant effect of barium titanate, improving the compatibility of modified barium titanate powder under the action of an organic solution, embedding the coating slurry into micropores of the non-woven paper through hot pressing treatment, so that the pore diameter of the micropores of the non-woven paper is reduced, the pore diameter and the thickness of the non-woven paper are controlled, the problem of lithium dendrite is solved, and the technical defect that the existing non-woven paper is too large in pore diameter and thickness and cannot be applied to an ion battery is overcome.)

1. The preparation method of the nonwoven paper ion battery diaphragm is characterized by comprising the following steps:

step 1, mixing modified barium titanate powder with an organic solution to obtain a coating slurry;

and 2, coating the coating slurry on the surface of non-woven paper, and performing hot pressing to obtain the non-woven paper ion battery diaphragm, wherein the pore diameter of the non-woven paper ion battery diaphragm is 80-500 nm.

2. The production method according to claim 1, wherein the solute of the organic solution is selected from one or more of polyvinylidene fluoride, polyethylene oxide, and cyclodextrin; the solution of the organic solution is selected from one or more of N-methyl-2-pyrrolidone, N-dimethylformamide and dimethyl sulfoxide.

3. The method for preparing the non-woven paper according to the claim 1, wherein the non-woven paper is made of one or more materials selected from polycarbonate, polypropylene and nylon.

4. The method according to claim 1, wherein the method for preparing the modified barium titanate powder comprises the steps of:

step one, dispersing barium titanate, hexachlorocyclotriphosphazene, a monomer and a catalyst in a reaction solvent, and reacting to obtain modified barium titanate; wherein the monomer is polyol or sodium polyol;

and step two, drying the modified barium titanate to obtain modified barium titanate powder.

5. The method according to claim 4, wherein the particle size of the barium titanate is 20nm to 5000 nm.

6. The preparation method according to claim 4, wherein the reaction temperature is 25-110 ℃ and the reaction time is 0.5-4 h.

7. The method according to claim 4, wherein the polyhydric alcohol is one or more of 1, 4-butanediol, ethylene glycol, glycerol, 1, 3-propanediol and 2, 3-butanediol;

the catalyst is one or more of triethylamine, pyridine, calcium hydride and sodium hydride;

the reaction solvent is one or more of acetone, ethanol and acetonitrile.

8. The method according to claim 1, wherein the hot-pressing temperature is 30 to 200 ℃, the hot-pressing pressure is 3 to 70MPa, and the hot-pressing time is 5 to 180 s.

9. The preparation method according to claim 1, wherein step 1 further comprises a dispersant, and step 1 is to mix modified barium titanate powder, the dispersant and an organic solvent to obtain the coating slurry.

10. A nonwoven paper ion battery separator comprising the nonwoven paper ion battery separator produced by the production method according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of ion batteries, and particularly relates to a nonwoven paper ion battery diaphragm and a preparation method thereof.

Background

The ion battery is composed of four parts: positive electrode, electrolyte, diaphragm and negative electrode. The diaphragm basically serves to isolate the positive electrode from the negative electrode and provides a channel for the transmission of lithium ions. Common diaphragms in the market are PP, PE or PP/PE/PP three-layer membranes and the like, but PP and PE are high polymer materials, the melting point of the former is 167 ℃, the melting point of the latter is 135 ℃, and the membranes of the former and the latter are easy to rupture under the high-temperature condition. Moreover, the lithium dendrite growing at the negative electrode can also pierce the polyolefin diaphragm, so that the contact of the positive electrode and the negative electrode of the battery can cause explosion; moreover, PP and PE are nonpolar materials, so that the wettability of the electrolyte is poor, and the liquid absorption and retention performances are poor.

Nonwoven paper diaphragms are widely used in the fields of lead-acid batteries, alkaline batteries, nickel-hydrogen batteries, supercapacitors and the like, and due to the fact that nonwoven paper has excellent heat resistance, high film breaking temperature and other properties, the nonwoven paper has attracted more and more attention in the lithium battery industry in recent years. However, due to the limitation of the preparation process of the non-woven paper, the pore size and thickness of the existing non-woven paper are large, and when the non-woven paper is applied to an ion battery, the pore size is too large, so that the battery is short-circuited, and the non-woven paper is difficult to apply to the field of the ion battery.

Disclosure of Invention

In view of this, the application provides a nonwoven paper ion battery diaphragm and a preparation method thereof, which can effectively solve the technical defects that the existing nonwoven paper has too large aperture and thickness and cannot be applied to an ion battery.

The invention provides a preparation method of a non-woven paper ion battery diaphragm, which comprises the following steps:

step 1, mixing modified barium titanate powder with an organic solution to obtain a coating slurry;

and 2, coating the coating slurry on the surface of non-woven paper, and performing hot pressing to obtain the non-woven paper ion battery diaphragm, wherein the pore diameter of the non-woven paper ion battery diaphragm is 80-500 nm.

Preferably, the solute of the organic solution is selected from one or more of polyvinylidene fluoride, polyethylene oxide and cyclodextrin; more preferably, the solute of the organic solution is selected from PVDF (polyvinylidene fluoride), PVDF has the function of a binder, and meanwhile, PVDF can be matched with modified barium titanate powder to regulate the pore size of the non-woven paper and improve the liquid absorption and retention capacity of the non-woven paper.

Preferably, the solution of the organic solution is selected from one or more of N-methyl-2-pyrrolidone, N-dimethylformamide, and dimethylsulfoxide.

Preferably, the material of the non-woven paper is selected from one of polycarbonate, polypropylene or nylon; more preferably, the material of the non-woven paper is selected from polycarbonate.

Preferably, the method for preparing the modified barium titanate powder comprises the following steps:

step one, dispersing barium titanate, hexachlorocyclotriphosphazene, a monomer and a catalyst in a reaction solvent, and reacting to obtain modified barium titanate; wherein the monomer is polyol or sodium polyol;

and step two, drying the modified barium titanate to obtain modified barium titanate powder.

Wherein the mixing mass ratio of the barium titanate to the hexachlorocyclotriphosphazene is 1 (1-20); the molar ratio of the hexachlorocyclotriphosphazene to the monomer is 1 (3-6); preferably, the molar ratio of the hexachlorocyclotriphosphazene to the monomer is 1 (2-4).

The modified barium titanate is barium titanate particles with the surfaces coated with ring-crosslinked polyphosphazene coating layers, and the flame retardant property of the barium titanate is effectively improved by using polyphosphazene. The polyphosphazene is adopted to coat the barium titanate, and the compatibility of polyvinylidene fluoride (PVDF) and barium titanate can be improved.

Preferably, the particle size of the barium titanate is 20nm to 5000nm, and preferably, the particle size of the barium titanate is 50nm to 1000 nm.

The application uses barium titanate with the particle size of 20 nm-5000 nm, which can control the pore size of the non-woven paper and control the pore size of the non-woven paper in a proper range, and can inhibit shuttling of other tetravalent manganese ions and polysulfide compounds through polarization effect while ensuring shuttling of lithium ions.

Preferably, the reaction temperature is 25-110 ℃, and the reaction time is 0.5-4 h; preferably, the temperature of the reaction is 60 ℃ and the time of the reaction is 4 h.

Preferably, the polyhydric alcohol is one or more of 1, 4-butanediol, ethylene glycol, glycerol, 1, 3-propanediol and 2, 3-butanediol;

the catalyst is one or more of triethylamine, pyridine, calcium hydride and sodium hydride;

the reaction solvent is one or more of acetone, ethanol and acetonitrile.

The application provides a specific preparation method, which comprises the following steps:

a) performing ultrasonic dispersion on barium titanate and hexachlorocyclotriphosphazene in a reaction solvent for 0.2-2 h to obtain a first mixed solution;

b) then adding a monomer and a catalyst, stirring and reacting for 0.5-4 h at 25-110 ℃, filtering, washing, and drying at 75-85 ℃ to obtain modified barium titanate powder.

Preferably, step 1 further comprises a dispersant, and step 1 specifically is to mix modified barium titanate powder, the dispersant and an organic solvent to obtain a coating slurry.

Wherein the dispersant is the conventional dispersant, and is selected from sodium tripolyphosphate or/and sodium dodecyl sulfate.

Preferably, the hot pressing temperature is 30-200 ℃, the hot pressing pressure is 3-70 Mpa, and the hot pressing time is 5-180 s.

More preferably, the hot pressing temperature is 60-150 ℃, the pressure is 5-50 Mpa, and the hot pressing time is 10-120 s.

Preferably, the surface density of the non-woven paper is 5-20 g/cm³Preferably 8 to 18g/cm³。

The application also discloses a non-woven paper ion battery diaphragm which comprises the non-woven paper ion battery diaphragm prepared by the preparation method.

The invention aims to solve the technical problem that the pore diameter and the thickness of the non-woven paper in the prior art are too large, so that the non-woven paper cannot be applied to an ion battery. Therefore, the invention provides a non-woven paper ion battery diaphragm, which is prepared by coating modified barium titanate powder on the surface of non-woven paper and carrying out hot pressing. The barium titanate is modified, the flame retardant effect of the barium titanate is improved, the compatibility of the modified barium titanate powder is improved under the action of an organic solution, the particle size of the modified barium titanate powder can be single particle size or different particle sizes, the coating slurry is embedded into micropores of the non-woven paper through hot pressing, the pore diameter of the micropores of the non-woven paper is reduced, the pore size and the thickness of the non-woven paper are controlled, the problem of lithium dendrite is solved, the pore size and the thickness of the non-woven paper are controlled in a proper range (the pore size of a non-woven paper ion battery diaphragm is 80-500 nm), shuttle of specific ions (such as lithium ions) on the non-woven paper ion battery diaphragm can be guaranteed, shuttle of other ions on the non-woven paper ion battery diaphragm is restrained, and the service life and the safety of the battery are effectively improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

FIG. 1 is a macro topography of a product 1 prepared in example 1 of the present application;

FIG. 2 is a microscopic topography of product 1;

fig. 3 is a micro-topography of the product 10 provided herein.

Detailed Description

The application provides a non-woven paper ion battery diaphragm and a preparation method thereof, which can effectively overcome the technical defects that the existing non-woven paper has too large aperture and thickness and cannot be applied to an ion battery.

The technical solutions in the embodiments of the present invention will be 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.

The materials used in the following examples are commercially available or self-made, and the nonwoven paper used in the following examples is polycarbonate PC having an areal density of 12g/cm³。