阅读说明：本技术 一种改性纳米陶瓷颗粒及其制备方法、陶瓷隔膜浆料及其制备方法、隔膜和锂离子电池 (Modified nano ceramic particles and preparation method thereof, ceramic diaphragm slurry and preparation method thereof, diaphragm and lithium ion battery ) 是由 顾岚冰 朱忠泗 邱敏 李倩伟 何巍 于 2020-05-15 设计创作，主要内容包括：本发明提供一种改性纳米陶瓷颗粒及其制备方法、陶瓷隔膜浆料及其制备方法、隔膜和锂离子电池。所述改性纳米陶瓷颗粒含有极性基团,所述极性基团包括乙酰基。所述改性纳米陶瓷颗粒的制备方法包括：将配方量的带有含氨基团的纳米陶瓷颗粒、乙酰化剂和催化剂混合,进行反应,得到所述改性纳米陶瓷颗粒。本发明提供的陶瓷隔膜浆料对环境无毒无害,使用本发明的陶瓷隔膜浆料制备的隔膜可以使电池的循环性能和倍率性能有很大提高。(The invention provides a modified nano ceramic particle and a preparation method thereof, ceramic diaphragm slurry and a preparation method thereof, a diaphragm and a lithium ion battery. The modified nano-ceramic particles contain polar groups, and the polar groups comprise acetyl groups. The preparation method of the modified nano ceramic particles comprises the following steps: mixing the nano ceramic particles with the amino-containing group, an acetylating agent and a catalyst according to the formula ratio, and reacting to obtain the modified nano ceramic particles. The ceramic diaphragm slurry provided by the invention is non-toxic and harmless to the environment, and the diaphragm prepared by using the ceramic diaphragm slurry can greatly improve the cycle performance and rate capability of a battery.)

1. A modified nanoceramic particle, comprising a polar group, wherein the polar group comprises an acetyl group.

2. The modified nanoceramic particle of claim 1, wherein the particle size of the modified nanoceramic particle is 10-100 nm;

preferably, the raw materials of the modified nano ceramic particles comprise nano ceramic particles with amino groups, an acetylating agent and a catalyst;

preferably, the raw material of the nano ceramic particles with the ammonia-containing groups comprises a ceramic precursor, water and ammonia-containing substances;

preferably, the ammonia containing substance comprises an amino sugar and/or an amino sugar derivative;

preferably, the aminosugar comprises glucosamine and/or 2-amino-2-deoxy sugar;

preferably, the aminosugar derivative comprises any one or a combination of at least two of N-acetylglucosamine, sialic acid, a glucosamine ester or an aminoglycoside antibiotic;

preferably, the ceramic precursor comprises a silicon source and/or a titanium source;

preferably, the silicon source comprises any one or a combination of at least two of hemisiloxane, orthosilicate ester, 3-aminopropyltriethoxysilane, aminopropyltriethoxysilane or bornyltriethoxysilane;

preferably, the titanium source comprises any one of titanium sulfate, titanyl sulfate, titanium tetrachloride or tetrabutyl titanate or a combination of at least two thereof;

preferably, the raw materials of the nano ceramic particles with the amino groups comprise the following components in parts by weight:

1-10 parts of ceramic precursor

40-200 parts of water

1-100 parts of ammonia-containing substance.

3. The modified nanoceramic particle of claim 1 or 2, wherein the acetylating agent comprises acetic anhydride and/or acetyl chloride;

preferably, the catalyst is a peracetylation catalyst;

preferably, the peracetylation catalyst comprises any one or a combination of at least two of pyridine, sodium acetate, perchloric acid or zinc chloride;

preferably, the raw materials of the modified nano ceramic particles comprise the following components in parts by weight:

1.2-105 parts of nano ceramic particles containing amino groups

1-10 parts of acetylating agent

0.1-10 parts of catalyst.

4. The method for preparing modified nanoceramic particles according to any one of claims 1-3, wherein the method comprises: mixing the nano ceramic particles with the amino-containing group, an acetylating agent and a catalyst according to the formula ratio, and reacting to obtain the modified nano ceramic particles.

5. The production method according to claim 4, wherein the reaction is carried out under stirring conditions;

preferably, the reaction time is 10-14 h;

preferably, the temperature of the reaction is 15-35 ℃;

preferably, the preparation method of the nano ceramic particles with the ammonia-containing group comprises the following steps: mixing the ceramic precursor, water and ammonia-containing substances according to the formula ratio, reacting, carrying out solid-liquid separation, and drying to obtain the modified nano ceramic particles;

preferably, in the method for preparing the nano ceramic particles containing the amino groups, the reaction temperature is 40-80 ℃;

preferably, in the method for preparing the nano ceramic particles containing the amino groups, the reaction time is 4-12 h;

preferably, in the method for preparing the nano ceramic particles having the amino group, the reaction is performed under stirring conditions.

6. A nanoceramic slurry, wherein the ceramic separator slurry comprises modified nanoceramic particles according to any one of claims 1-3;

preferably, the nano-ceramic slurry further comprises a binder and a solvent;

preferably, the binder comprises any one or a combination of at least two of waterborne epoxy resin, waterborne polyurethane, ethylene-vinyl acetate copolymer, polyacrylic copolymer, copolymerization modified polyvinyl alcohol, waterborne silicone resin, polyvinylidene fluoride, butyronitrile-polyvinyl chloride blend, polypropylene or polyethylene;

preferably, the solvent comprises an aqueous solvent or an oily solvent;

preferably, the aqueous solvent comprises any one of water, ethanol or glycerol or a combination of at least two thereof;

preferably, the oily solvent comprises acetone and/or N-methylpyrrolidone;

preferably, the ceramic diaphragm slurry comprises the following raw materials in parts by weight:

7. the method of preparing the nanoceramic slurry according to claim 6, comprising the steps of:

mixing the modified nano-ceramic particles of any one of claims 1 to 3 with a formulated amount of a binder and a solvent to obtain the ceramic separator slurry.

8. The method for preparing according to claim 7, characterized in that it comprises the following steps:

(1) mixing the ceramic precursor, water and ammonia-containing substances according to the formula amount, reacting at the temperature of 40-80 ℃ under the condition of stirring for 4-12h, carrying out solid-liquid separation, and drying to obtain nano ceramic particles with ammonia-containing groups;

(2) mixing the nano ceramic particles with the amino-containing groups, an acetylating agent and a catalyst according to a formula amount, reacting at the temperature of 15-35 ℃ for 10-14h under the condition of stirring to obtain modified nano ceramic particles containing polar groups, and mixing the modified nano ceramic particles with a binder and a solvent according to the formula amount to obtain the ceramic diaphragm slurry, wherein the polar groups comprise acetyl groups.

9. A separator, wherein the ceramic separator slurry according to claim 6 is used in a process for producing a separator.

10. A lithium ion battery comprising the separator of claim 9.

Technical Field

The invention belongs to the technical field of batteries, and relates to modified nano ceramic particles and a preparation method thereof, ceramic diaphragm slurry and a preparation method thereof, a diaphragm and a lithium ion battery.

Background

Various new energy batteries represented by lithium ion batteries are widely applied to the fields of electric automobiles and energy storage at present. With the increasing demand of new energy batteries in the market, how to increase the production efficiency and expand the capacity while ensuring the safety and effectiveness of the batteries becomes a problem to be solved by various new energy battery manufacturers and their upstream suppliers. The main components of the battery comprise a shell, electrolyte, a positive electrode, a negative electrode, a diaphragm and the like, wherein the diaphragm serving as a core component of the battery is mainly coated with powder ceramic at present, and the production relates to a process of preparing a slurry from the powder ceramic material and then coating the slurry on the surface of a base material. The technical core of the coating processing lies in the formula of the slurry, and enterprises need to use different slurry formulas according to the positioning of a diaphragm product and the requirements of downstream on specific properties, and the total coating cost ratio is as high as about 65%. The ceramic coating slurry mainly comprises four main components of ceramic particles, a binder, a solvent and an additive.

Commonly used ceramic materials include silicon dioxide, titanium dioxide, zirconium dioxide, aluminum oxide, and the like. The sizes of the commercial ceramic particles are in micron order, and the ceramic particles are easy to agglomerate and disperse unevenly when being used for preparing slurry, so that the liquid absorption and retention performance of the coated diaphragm on electrolyte are influenced. In addition, the binder is also one of indispensable components in the process of preparing the slurry, and the quality of the binder has a direct influence on the quality of the finished battery. The mainstream adhesive special for the ceramic diaphragm of the lithium battery at present is an aqueous emulsion adhesive of an acrylate system, and the adhesive and the production process thereof tend to be mature and have wide application. However, the emulsion system is a thermodynamically unstable system, and is easily broken due to mechanical shearing, electrolytes, temperature change, long-time storage and the like, and the emulsion type adhesive needs to be added with various additives in the preparation process, so that the components and the process flow are complex, and various additives may cause unpredictable influence on the performance of the adhesive product.

CN105552285A discloses a ceramic coating diaphragm which is a symmetrical five-layer layered structure and comprises ceramic coatings on two outermost layers, chlorinated polyolefin coatings on two outer layers and a substrate diaphragm in an intermediate layer. The preparation method comprises the steps of modifying ceramic particles to prepare ceramic coating slurry, coating chlorinated polyolefin paint on a substrate diaphragm, drying to form a chlorinated polyolefin coating, and finally coating the ceramic coating slurry on the chlorinated polyolefin coating of the substrate diaphragm, and drying to obtain the ceramic coating diaphragm. The diaphragm of the scheme has a complex structure, four layers of coatings need to be coated, the cost is increased, and the performance of the ceramic coating needs to be further enhanced.

CN106299222A discloses a separator and a secondary battery thereof. The diaphragm comprises a base material and a coating attached to the surface of the base material, wherein the coating contains an antistatic additive, a binder and ceramic material particles, the antistatic additive is selected from carbon materials, and the ratio of the thickness of the coating to the median particle size of the ceramic material particles is 1: 0.5-1.5. However, in this scheme, the bonding force between the high ceramic powder and the binder and the electrolyte needs to be enhanced, and the performance of the ceramic coating needs to be further enhanced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide modified nano ceramic particles and a preparation method thereof, ceramic diaphragm slurry and a preparation method thereof, a diaphragm and a lithium ion battery. The modified nano ceramic particles provided by the invention have high polarity of acetyl, and can improve the binding force with a binder and electrolyte when being applied to the field of lithium batteries. The ceramic diaphragm slurry provided by the invention can improve the binding force of ceramic powder, a binder and electrolyte, and the diaphragm prepared by using the slurry can greatly improve the cycle performance and the rate capability of a lithium ion battery.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a modified nanoceramic particle comprising a polar group, the polar group comprising an acetyl group.

The modified nano ceramic particles provided by the invention are uniformly dispersed in use, have large specific surface area, good stability and good air permeability, and are beneficial to ion conductivity. The modified nano ceramic particles provided by the invention contain acetyl on the particle surface, and the acetyl has larger polarity, so that the binding force with a binder and electrolyte can be improved when the modified nano ceramic particles are applied to the field of lithium batteries. That is because the binder also contains a large number of polar groups, and the electrolyte also contains a large number of polar components, when these are contacted with polar acetyl groups, their inherent dipoles repel homopolarity and attract heteropolarity, so that they are aligned, and intermolecular force, called orienting force, is generated. Therefore, the open-chain is characterized in that acetyl formed by acetylating amino-containing groups on the surfaces of modified nano ceramic particles can also serve as a 'molecular bridge' for connecting ceramics and a binder and connecting the ceramics and electrolyte, and the binding force of the ceramic powder, the binder and the electrolyte is greatly improved. It should be noted that the application field of the modified nano ceramic particles of the present application is not limited to the field of lithium batteries.

The following is a preferred technical solution of the present invention, but not a limitation to the technical solution provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solution.

In a preferred embodiment of the present invention, the modified nano-ceramic particles have a particle size of 10 to 100nm, for example, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100 nm.

Preferably, the raw materials of the modified nano-ceramic particles comprise nano-ceramic particles with amino groups, an acetylating agent and a catalyst. The raw materials of the modified nano-ceramic particles are raw materials used for preparing the modified nano-ceramic particles.

Wherein, the acetylating agent is used for acetylating the amino-containing groups of the modified nano ceramic particles, and the catalyst is used for catalyzing the acetylating.

Preferably, the raw material of the nano ceramic particles with the ammonia-containing groups comprises a ceramic precursor, water and ammonia-containing substances.

The significance of adopting the nano ceramic particle raw material with the amino group is that in the process of hydrolyzing and recrystallizing a ceramic powder precursor in water, the surface of a crystal seed is negatively charged due to the hydroxyl group, the amino group-containing substance is positively charged due to the amino group, the strong positive and negative charge interaction enables the crystal seed to be adsorbed on the surface of a crystal monomer, the positive and negative charge attraction is stronger than the hydrogen bond interaction between the hydroxyl groups, and the crystal monomers do not tend to agglomerate with each other, so that the nano-scale uniformly dispersed ceramic particles can be obtained finally. The obtained nano ceramic particles have the amino groups, and the provided nano ceramic particles with the amino groups are uniformly dispersed, have large specific surface area, good stability and good air permeability, and are beneficial to ion conductivity.

Preferably, the ammonia containing substance comprises an amino sugar and/or an amino sugar derivative.

Preferably, the aminosugar comprises glucosamine and/or 2-amino-2-deoxy sugar.

Preferably, the aminosugar derivative comprises any one or a combination of at least two of N-acetylglucosamine, sialic acid, a glucosamine ester or an aminoglycoside antibiotic.

The aminoglycoside antibiotic comprises any one or the combination of at least two of streptomycin, gibberellin, gentamicin or nojirimycin.

Preferably, the ceramic precursor comprises a silicon source and/or a titanium source.

Preferably, the silicon source comprises any one of or a combination of at least two of a silsesquioxane (POSS), an orthosilicate (e.g., tetraethoxysilane TEOS), 3-Aminopropyltriethoxysilane (APTES), Aminopropyltriethoxysilane (APS), or borylpropyltriethoxysilane (MPTS).

Preferably, the titanium source comprises any one of titanium sulfate, titanyl sulfate, titanium tetrachloride or tetrabutyl titanate, or a combination of at least two thereof.

As a preferable technical scheme of the invention, the raw materials of the ceramic particles with the amino groups comprise the following components in parts by weight:

1-10 parts of ceramic precursor

40-200 parts of water

1-100 parts of ammonia-containing substance.

In the raw materials of the ceramic particles of the present invention, the weight portion of the ceramic precursor is 1 to 10 parts, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts; the water is 40-200 parts, such as 40 parts, 60 parts, 80 parts, 100 parts, 120 parts, 140 parts, 160 parts, 180 parts or 200 parts by weight, and the ammonia-containing substance is 1-100 parts, such as 1 part, 20 parts, 40 parts, 60 parts, 80 parts or 100 parts by weight.

As a preferred technical scheme of the invention, the acetylating agent comprises acetic anhydride and/or acetyl chloride.

Amino sugar and derivatives thereof are adopted as ammonia-containing substances, acetic anhydride is adopted as an acetylating agent, and the aim is that a large number of hydroxyl groups in the amino sugar and the derivatives thereof are replaced by strong polar acetyl groups in the acetylation reaction process of the raw materials. Therefore, in the ceramic diaphragm slurry finally obtained by the invention, the ceramic particles mainly comprise the nano-scale ceramic powder and the acetyl sugar adhered on the nano-scale ceramic powder.

Preferably, the catalyst is a peracetylation catalyst.

Polar groups (amino sugar and derivatives thereof) adsorbed on the surface of the modified nano ceramic particles are easily acetylated into peracetyl sugar under the action of a catalyst and an acetylating agent, and the peracetyl sugar refers to a sugar derivative in which all free hydroxyl groups or amino groups in a sugar molecule are protected by acetyl.

Preferably, the peracetylation catalyst comprises any one or a combination of at least two of pyridine, sodium acetate, perchloric acid or zinc chloride. However, the method is not limited to the above-mentioned materials, and other protonic acids or Lewis acids which can perform the same function can be used in the present invention.

Preferably, the raw materials of the modified nano ceramic particles comprise the following components in parts by weight:

1.2-105 parts of nano ceramic particles containing amino groups

1-10 parts of acetylating agent

0.1-10 parts of catalyst.

In the raw material of the ceramic particle provided by the invention, the weight portion of the nano ceramic particle with the ammonia-containing group is 1.2-105 parts, such as 1.2 parts, 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts or 105 parts, etc., the weight portion of the acetylating agent is 1-10 parts, such as 1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts, etc., and the weight portion of the catalyst is 0.1-10 parts, such as 0.1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts, etc.

In a second aspect, the present invention provides a method for preparing modified nano-ceramic particles according to the first aspect, wherein the method comprises: mixing the nano ceramic particles with the amino-containing group, an acetylating agent and a catalyst according to the formula ratio, and reacting to obtain the modified nano ceramic particles.

In the preparation method provided by the invention, the modified nano ceramic particles are fully acetylated with amino groups under the action of an acetylating agent and a catalyst, the acetyl groups have high polarity, the binder also contains a large amount of polar groups, the electrolyte also contains a large amount of polar components, and when the modified nano ceramic particles are contacted with the polar acetyl groups, the inherent dipoles repel each other and attract each other, and the opposite poles are directionally arranged to generate intermolecular acting force, namely aligning force. Therefore, in the preparation method of the open-chain reaction, acetyl formed by acetylating the amino-containing groups on the surface of the modified nano ceramic particles can also serve as a 'molecular bridge' for connecting the ceramic and the binder and the ceramic and the electrolyte, so that the binding force of the ceramic powder, the binder and the electrolyte is greatly improved.

As a preferred embodiment of the present invention, the reaction is preferably carried out under stirring.

Preferably, the reaction time is 10-14h, such as 10h, 11h, 12h, 13h or 14h, etc.

Preferably, the temperature of the reaction is 15-35 ℃, such as 15 ℃, 20 ℃, 25 ℃, 30 ℃ or 35 ℃ and the like.

Preferably, the preparation method of the nano ceramic particles with the ammonia-containing group comprises the following steps: mixing the ceramic precursor, water and ammonia-containing substances according to the formula ratio, reacting, carrying out solid-liquid separation, and drying to obtain the modified nano ceramic particles.

Preferably, in the method for preparing the nano ceramic particles having an amino group, the reaction temperature is 40 to 80 ℃, for example, 40 ℃, 50 ℃, 60 ℃, 70 ℃ or 80 ℃. In the invention, if the reaction temperature for adsorbing the ceramic precursor by the ammonia-containing substance is too high, the ammonia-containing substance is carbonized, so that the structure of the ammonia-containing substance is damaged, and the subsequent acetylation process is influenced; if the reaction temperature for absorbing the ceramic precursor by the ammonia-containing substance is too low, the hydrolysis and crystallization process of the precursor is slowed, and the reaction is not thorough.

Preferably, in the method for preparing the nano ceramic particles containing the amino groups, the reaction time is 4-12h, such as 4h, 6h, 8h, 10h or 12 h.

Preferably, in the method for preparing the nano ceramic particles having the amino group, the reaction is performed under stirring conditions.

In a third aspect, the present invention provides a nano-ceramic slurry comprising the modified nano-ceramic particles of the first aspect.

Preferably, the nano-ceramic slurry further includes a binder and a solvent.

In the ceramic diaphragm slurry provided by the invention, the modified nano ceramic particles are the main body material for forming a ceramic layer on the diaphragm substrate when the slurry is used. The binder is used to adjust the viscosity of the slurry and bind the modified nano ceramic particles to form a ceramic layer on the separator substrate. The solvent is used to disperse or dissolve the other components.

The significance of adopting the modified nano ceramic particle raw material is that in the process of hydrolyzing and recrystallizing a ceramic powder precursor in water, the surface of a crystal seed is negatively charged due to hydroxyl, an ammonia-containing substance is positively charged due to amino, the strong positive and negative charges interact to enable the crystal seed to be adsorbed on the surface of a crystal monomer, the positive and negative charges are attracted to be stronger than the hydrogen bonding effect between the hydroxyl, and the crystal monomers cannot tend to agglomerate with each other, so that the nano-scale uniformly dispersed ceramic particles can be obtained finally. The obtained modified nano ceramic particles have amino groups, and the provided modified nano ceramic particles are uniform in dispersion, large in specific surface area, good in stability and good in air permeability, and are beneficial to ion conductivity.

Preferably, the binder comprises any one or a combination of at least two of waterborne epoxy resin, waterborne polyurethane, ethylene-vinyl acetate copolymer, polyacrylic copolymer, copolymerization modified polyvinyl alcohol, waterborne silicone resin, polyvinylidene fluoride, butyronitrile-polyvinyl chloride blend, polypropylene or polyethylene.

In the invention, acetyl has relatively high polarity, so the total acetyl sugar has relatively high water solubility and plays the role of a surfactant, on the other hand, binders such as esters, alcohol copolymers and the like added into the ceramic slurry contain a large amount of polar groups, and the electrolyte also contains a plurality of polar components, when the binders are contacted with the polar acetyl, the inherent dipoles repel each other and attract each other, and the inherent dipoles are directionally arranged to generate intermolecular acting force, namely, orienting force. Therefore, the acetyl with strong polarity in the invention can also be used as a 'molecular bridge' for connecting the ceramic and the binder and the ceramic and the electrolyte, thereby greatly improving the binding force of the ceramic powder, the binder and the electrolyte.

Preferably, the solvent comprises an aqueous solvent or an oily solvent.

Preferably, the aqueous solvent comprises any one of water, ethanol or glycerol or a combination of at least two thereof.

Preferably, the oily solvent comprises acetone and/or N-methylpyrrolidone.

Preferably, the ceramic diaphragm slurry comprises the following raw materials in parts by weight:

in the raw material of the ceramic diaphragm slurry provided by the invention, the weight part of the nano ceramic particles with the ammonia groups is 1.2-105 parts, such as 1.2 parts, 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts or 105 parts, etc., the weight part of the acetylating agent is 1-10 parts, such as 1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts, etc., the weight part of the catalyst is 0.1-10 parts, such as 0.1 part, 2 parts, 4 parts, 6 parts, 8 parts or 10 parts, etc., the weight part of the binder is 0.1-1 part, such as 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part or 1 part, etc., and the weight part of the solvent is 100-500 parts, such as 100 parts, 200 parts, 300 parts, 400 parts or 500 parts, etc.

In a fourth aspect, the present invention provides a method for preparing the nano-ceramic slurry according to the third aspect, the method comprising the steps of:

mixing the modified nano ceramic particles as described in the first aspect with a formula amount of a binder and a solvent to obtain the ceramic diaphragm slurry.

In the preparation method provided by the invention, the modified nano ceramic particles are fully acetylated with amino groups under the action of an acetylating agent and a catalyst, the acetyl groups have high polarity, the binder also contains a large amount of polar groups, the electrolyte also contains a large amount of polar components, and when the modified nano ceramic particles are contacted with the polar acetyl groups, the inherent dipoles repel each other and attract each other, and the opposite poles are directionally arranged to generate intermolecular acting force, namely aligning force. Therefore, in the preparation method of the open-chain reaction, acetyl formed by acetylating the amino-containing groups on the surface of the modified nano ceramic particles can also serve as a 'molecular bridge' for connecting the ceramic and the binder and the ceramic and the electrolyte, so that the binding force of the ceramic powder, the binder and the electrolyte is greatly improved.

As a further preferable technical scheme of the preparation method of the ceramic diaphragm slurry, the method comprises the following steps:

(1) mixing the ceramic precursor, water and ammonia-containing substances according to the formula amount, reacting at the temperature of 40-80 ℃ under the condition of stirring for 4-12h, carrying out solid-liquid separation, and drying to obtain nano ceramic particles with ammonia-containing groups;

(2) mixing the nano ceramic particles with the amino-containing groups, an acetylating agent and a catalyst according to a formula amount, reacting at the temperature of 15-35 ℃ for 10-14h under the condition of stirring to obtain modified nano ceramic particles containing polar groups, and mixing the modified nano ceramic particles with a binder and a solvent according to the formula amount to obtain the ceramic diaphragm slurry, wherein the polar groups comprise acetyl groups.

In a fifth aspect, the present invention provides a separator using the ceramic separator slurry according to the third aspect in a process for producing the separator.

In a sixth aspect, the present invention provides a lithium ion battery comprising the separator according to the fifth aspect.

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

(1) the ceramic diaphragm slurry provided by the invention is nontoxic and harmless to the environment, the ceramic particles in the ceramic diaphragm slurry are uniformly dispersed, the specific surface area is large, the stability and the air permeability are good, the ion conductivity is facilitated, the binding force between the ceramic particles and the diaphragm base film and the affinity to electrolyte are greatly improved, and the liquid absorption speed and the liquid retention capacity of the diaphragm are increased, so that the diaphragm prepared by using the ceramic diaphragm slurry provided by the invention can greatly improve the cycle performance and the rate capability of a battery.

(2) In the preparation method of the modified nano ceramic particles, the surface of the crystal seed is negatively charged due to hydroxyl groups in the hydrolysis and recrystallization processes of the ceramic powder precursor, the aminosugar and the derivatives thereof are positively charged due to amino groups, the aminosugar and the derivatives thereof are adsorbed on the surface of the crystal monomer due to strong positive and negative charge interaction, the positive and negative charge attraction is stronger than the hydrogen bond interaction between the hydroxyl groups, and the crystal monomers do not tend to agglomerate with each other, so that the nano-scale uniformly dispersed ceramic particles can be obtained.

(3) In the raw materials of the ceramic diaphragm slurry provided by the invention, the amino groups (amino sugar and derivatives thereof) on the surfaces of the nano ceramic particles with the amino groups are easily acetylated into the peracetyl sugar, the acetyl groups have higher polarity and have considerable water solubility, so the peracetyl sugar can play a role of a surfactant, on the other hand, binders such as esters, alcohol copolymers and the like added into the ceramic slurry contain a large amount of polar groups, and electrolyte also contains a large amount of polar components, when the binders contact with the polar acetyl groups, the inherent dipoles repel each other but attract each other, and are arranged in an oriented way to generate intermolecular acting force, so the strong polar acetyl groups in the invention can also serve as 'molecular bridges' for connecting the ceramic and the binder, and the ceramic and the electrolyte, and the binding force of the ceramic powder, the binder and the electrolyte is greatly improved.

Drawings

Fig. 1 is a schematic flow diagram of the preparation method provided in example 1.

Detailed Description

In order to better illustrate the present invention and facilitate the understanding of the technical solutions of the present invention, the present invention is further described in detail below. The following examples are merely illustrative of the present invention and do not represent or limit the scope of the claims, which are defined by the claims.

The following are typical but non-limiting examples of the invention: