A dry cell separator paper and a method for making the same

Abstract

The application relates to the technical field of diaphragm paper, and discloses dry battery diaphragm paper and a preparation method thereof. The dry battery diaphragm paper prepared by the application is composed of a composite fiber paper and a reinforcing slurry coated on the surface of the composite fiber paper, and has the advantages of excellent strength, high porosity, high alkali absorption rate, good wettability and the like; the composite fiber paper adopts a composite fiber prepared by blending of polypropylene fibers, aramid fibers and polyester fibers as a matrix, and modified aerogel is added to improve the tensile strength, flexibility and wettability to electrolyte of the diaphragm paper.

Description

Technical Field

[0001] This invention relates to the field of separator paper technology, and specifically to a dry cell battery separator paper and its preparation method. Background Technology

[0002] Dry cell batteries, also known as disposable batteries, are mainly composed of a positive electrode, a negative electrode, an electrolyte, a separator, and a casing. The separator, typically made of paper or plastic, serves as the material separating the positive and negative electrodes. Its primary function is to prevent direct contact and short circuits between the positive and negative electrodes, and to allow ions in the electrolyte to pass freely between them while preventing electrons from passing freely. Among all the components of a battery, the separator material plays a crucial role, and its quality directly affects battery performance.

[0003] Currently, commercially available separator papers are mainly made of polyethylene and polypropylene. However, stretch membranes made of polyolefins have low porosity, low liquid absorption, and low specific surface energy, resulting in poor affinity for electrolytes and poor dimensional stability. This makes them prone to short circuits caused by contact between the positive and negative electrodes, generating a large amount of heat instantly and potentially leading to battery fires or explosions, thus affecting battery safety. Furthermore, separator papers also need to provide thermal insulation to ensure that the battery can be protected by an automatic shut-off mechanism under abnormal conditions, preventing short circuits and overheating, thereby improving battery safety. Therefore, researchers need to develop separator papers with high porosity, high alkali absorption, good wettability, excellent tensile strength, and good thermal insulation properties. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a dry cell separator paper and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A dry cell battery separator paper consists of two parts: composite fiber paper and reinforcing pulp coated on the surface of the composite fiber paper.

[0007] The reinforcing slurry is obtained by mixing and stirring 2-5 parts of insulating filler, 25-35 parts of polyacrylic acid emulsion and 50-80 parts of deionized water.

[0008] The insulating filler is prepared by the following steps:

[0009] Polyvinylpyrrolidone was dispersed in ethanol, then xylene was added and mixed thoroughly. The mixture was then divided into two equal portions, labeled as solution A1 and solution A2. Silicon carbide nanocrystals were added to solution A1 and dispersed thoroughly to obtain solution B. Aluminum nitrate was added to solution A2 and mixed thoroughly to obtain solution C. Solutions B and C were mixed and sonicated for 10-20 minutes, and the pH was adjusted to 7-12. The mixture was then reacted at 15-35℃ for 40-60 minutes, allowed to stand and age for 2-3 days, centrifuged, washed, and dried. Finally, it was calcined at 600-800℃ for 1.5-3.5 hours to obtain the insulating filler.

[0010] Furthermore, in solutions A1 and A2, the ratio of polyvinylpyrrolidone, ethanol, and xylene is 0.6-1.4 g: 160 mL: 40 mL;

[0011] Furthermore, the concentration of silicon carbide nanocrystals in solution B is 0.1-0.3 mol / L, and the concentration of aluminum nitrate in solution C is 0.2-0.4 mol / L.

[0012] The method for preparing the composite fiber paper includes the following steps:

[0013] Step B1: Mix γ-aminopropyltriethoxysilane, tetraethyl orthosilicate and mercaptopropyltrimethoxysilane in deionized water, then add ammonia and stir for 8-12 hours. Filter, wash and dry to obtain functionalized silica.

[0014] Step B2: Disperse 5-aminoisophthalic acid in dimethylacetamide, add triethylamine and acryloyl chloride sequentially in an ice-water bath, heat to 40-60℃ and react for 3.5-4.5 h, then transfer to deionized water at 10℃ and stir for 10 min, filter, wash and dry to obtain the intermediate product;

[0015] Step B3: Disperse functionalized silica in deionized water, add intermediate product and triethylamine solution sequentially under nitrogen atmosphere, then adjust pH to 9.8-10.2, raise temperature to 75-85℃, react for 6-8 hours, filter, wash and dry to obtain grafted modified silica.

[0016] Step B4: Ultrasonically disperse the grafted modified silica and sodium alginate in deionized water for 30 min, then add glucono-delta-lactone solution under vigorous stirring to form a mixture. Pour the mixture into a mold and let it stand for 30-50 min to form a gel. Then freeze-dry the gel at -60℃ for 48 h to obtain the modified aerogel.

[0017] Step B5: Weigh the raw materials according to the weight parts, add 35-45 parts of polypropylene fiber, 20-30 parts of aramid fiber and 10-20 parts of polyester fiber into the pulper respectively, add deionized water to dissolve for 15-25 minutes, then use a light blade to pulp for 50-60 minutes until the fibers are completely dispersed, and you will get the three fiber pulps.

[0018] Step B6: Transfer the three types of pulp to the mixing tank, add deionized water to prepare a mass percentage concentration of 0.3%-0.7%, then add 1-2 mL of 0.5-1.5 wt% dispersant (carboxymethyl cellulose) and 25-35 parts of modified aerogel and stir to form a mixed pulp. Then dehydrate, press, dry and hot press the mixed pulp on a mesh fabric, and then roll and cut it to obtain composite fiber paper.

[0019] Further, in step B1, the ratio of γ-aminopropyltriethoxysilane, tetraethyl orthosilicate, mercaptopropyltrimethoxysilane, deionized water, and ammonia is 0.005-0.02 mol: 0.04-0.1 mol: 0.01-0.02 mol: 200 mL: 0.3-0.6 mL;

[0020] Further, in step B2, the ratio of 5-aminoisophthalic acid, dimethylacetamide, triethylamine, acryloyl chloride, and deionized water is 0.05-0.1 mol: 100 mL: 10-20 mL: 0.05-0.1 mol: 100 mL;

[0021] Furthermore, in step B3, the mass ratio of functionalized silica, deionized water, intermediate product and triethylamine solution is 0.5-1.5:100:1-5:1-3, and the triethylamine solution is prepared by mixing triethylamine and deionized water at a mass ratio of 0.5-1:20.

[0022] Furthermore, in step B4, the ratio of grafted modified silica, sodium alginate, deionized water, and glucono-delta-lactone solution is 0.4-1.2g:0.5-1g:50mL:10mL, and the glucono-delta-lactone solution is prepared by mixing glucono-delta-lactone and deionized water at a ratio of 0.3-0.6g:10mL.

[0023] Furthermore, in step B5, the mass percentage concentration of each fiber in the three fiber pulps is 0.5%-1.5%.

[0024] A method for preparing a dry cell battery separator paper includes the following steps:

[0025] The reinforcing slurry is evenly coated on the surface of the composite fiber paper to a thickness of 0.15-0.2 mm, and then dried to obtain the dry cell battery separator paper.

[0026] The beneficial effects of this invention are:

[0027] The dry cell separator paper prepared by this invention consists of two parts: composite fiber paper and reinforcing pulp coated on the surface of the composite fiber paper. This separator paper has advantages such as excellent strength, high porosity, high alkali absorption rate, and good wettability.

[0028] The reinforcing filler in the reinforcing slurry is formed by using silicon carbide whiskers as a base and alumina as a coating layer. After being introduced into the slurry, it is coated onto the surface of the composite fiber paper, which can improve the tensile strength and chemical stability of the separator paper. This is because silicon carbide nanocrystals can exert their excellent toughness and strength, thereby improving the tensile strength of the separator paper. At the same time, the alumina coating can utilize its excellent heat insulation properties to prevent short circuits and overheating, thereby improving the safety performance of the battery.

[0029] In the composite fiber paper, functionalized silica containing thiol and amino groups is first synthesized using γ-aminopropyltriethoxysilane, tetraethyl orthosilicate, and mercaptopropyltrimethoxysilane as silicon sources; then, an intermediate product containing a double bond structure is synthesized by reacting 5-aminoisophthalic acid and acryloyl chloride; next, graft-modified silica is synthesized by reacting the thiol groups in the functionalized silica with the double bonds in the intermediate product; then, modified aerogel is synthesized using graft-modified silica, sodium alginate, and glucono-delta-lactone as raw materials; finally, composite fiber paper is synthesized using polypropylene fiber, aramid fiber, and polyester fiber as matrix fibers, with the addition of modified aerogel and dispersant. The composite fiber paper uses a blend of polypropylene fiber, aramid fiber, and polyester fiber as the matrix. Polypropylene fiber improves the density and alkali resistance of the dry cell battery separator paper, which helps ensure the pore size and chemical stability of the separator paper. Aramid fiber contains a rigid benzene ring structure, exhibiting excellent heat resistance and oxidation resistance, significantly reducing the thermal shrinkage rate of the separator paper at high temperatures, avoiding battery fire hazards, and greatly improving safety. The introduction of modified aerogel improves the tensile strength, flexibility, and wettability of the separator paper to the electrolyte. This is because the modified aerogel incorporates sodium alginate and hydrophilic silica, which contain a large number of hydrophilic groups, such as amino and carboxyl groups. These groups can form a hydrophilic layer on the surface of the fiber paper, thereby improving the wettability to the electrolyte. Furthermore, the aerogel itself has an excellent pore structure and low mass, which can increase the porosity of the separator paper and reduce its basis weight. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] The insulating filler is prepared by the following steps:

[0033] Disperse 0.6 g of polyvinylpyrrolidone in 160 mL of ethanol, then add 40 mL of xylene and mix thoroughly. Divide the mixture into two equal portions, labeled as solution A1 and solution A2. Add 0.01 mol of silicon carbide nanocrystals to 100 mL of solution A1 and disperse thoroughly to obtain solution B. Add 0.02 mol of aluminum nitrate to 100 mL of solution A2 and mix thoroughly to obtain solution C. Mix solutions B and C, sonicate for 10 min, adjust the pH to 7, and react at 15 °C for 40 min. Allow the mixture to stand for 2 days, centrifuge, wash, dry, and then calcine at 600 °C for 1.5 h to obtain the insulating filler.

[0034] The preparation method of composite fiber paper includes the following steps:

[0035] Step B1: Mix 0.005 mol γ-aminopropyltriethoxysilane, 0.04 mol tetraethyl orthosilicate and 0.01 mol mercaptopropyltrimethoxysilane in 200 mL of deionized water, then add 0.3 mL of ammonia water and stir for 8 h. Filter, wash and dry to obtain functionalized silica.

[0036] Step B2: Disperse 0.05 mol of 5-aminoisophthalic acid in 100 mL of dimethylacetamide, add 10 mL of triethylamine and 0.05 mol of acryloyl chloride in sequence under ice-water bath, heat to 40 °C and react for 3.5 h, then transfer to 100 mL of 10 °C deionized water and stir for 10 min, filter, wash and dry to obtain the intermediate product;

[0037] Step B3: Disperse 0.5g of functionalized silica in 100g of deionized water. Under nitrogen atmosphere, add 1g of intermediate product and 1g of triethylamine solution in sequence. Then adjust the pH to 9.8, raise the temperature to 75℃, react for 6h, filter, wash, and dry to obtain grafted modified silica. The triethylamine solution is prepared by mixing triethylamine and deionized water in a mass ratio of 0.5:20.

[0038] Step B4: Disperse 0.4g of grafted modified silica and 0.5g of sodium alginate in 50mL of deionized water by ultrasonication for 30min. Then, add 10mL of glucono-delta-lactone solution under vigorous stirring to form a mixture. Pour the mixture into a mold and let it stand for 30min to form a gel. Then freeze-dry the gel at -60℃ for 48h to obtain the modified aerogel. The glucono-delta-lactone solution is prepared by mixing glucono-delta-lactone and deionized water at a ratio of 0.3g:10mL.

[0039] Step B5: Weigh the raw materials according to the weight parts, add 35 parts of polypropylene fiber, 20 parts of aramid fiber and 10 parts of polyester fiber into the pulper respectively, add deionized water to dissolve for 15 minutes, then beat with a light blade for 50 minutes until the fibers are completely dispersed, and the three fiber pulps are obtained. The mass percentage concentration of each fiber in the three fiber pulps is 0.5%.

[0040] Step B6: Transfer the three types of pulp to the mixing tank, add deionized water to prepare a mass percentage concentration of 0.3, then add 1 mL of 0.5 wt% dispersant (carboxymethyl cellulose) and 25 parts of modified aerogel and stir to form a mixed pulp. Then dehydrate, press, dry and hot press the mixed pulp on a mesh fabric, and then roll and cut it to obtain composite fiber paper.

[0041] Example 2

[0042] The insulating filler is prepared by the following steps:

[0043] 1 g of polyvinylpyrrolidone was dispersed in 160 mL of ethanol, and then 40 mL of xylene was added and mixed evenly. The mixture was then divided into two equal portions, labeled as solution A1 and solution A2. 0.02 mol of silicon carbide nanocrystals were added to 100 mL of solution A1 and dispersed evenly to obtain solution B. 0.03 mol of aluminum nitrate was added to 100 mL of solution A2 and mixed evenly to obtain solution C. Solution B and solution C were mixed and sonicated for 15 min, and the pH was adjusted to 9. The mixture was then reacted at 25 °C for 50 min, allowed to stand and age for 2.5 days, centrifuged, washed, dried, and then calcined at 700 °C for 2.5 h to obtain the insulating filler.

[0044] The preparation method of composite fiber paper includes the following steps:

[0045] Step B1: Mix 0.01 mol γ-aminopropyltriethoxysilane, 0.07 mol tetraethyl orthosilicate and 0.015 mol mercaptopropyltrimethoxysilane in 200 mL of deionized water, then add 0.45 mL of ammonia water and stir for 10 h. Filter, wash and dry to obtain functionalized silica.

[0046] Step B2: Disperse 0.075 mol 5-aminoisophthalic acid in 100 mL dimethylacetamide, add 15 mL triethylamine and 0.075 mol acryloyl chloride sequentially in an ice-water bath, heat to 50 °C and react for 4 h, then transfer to 100 mL deionized water at 10 °C and stir for 10 min, filter, wash and dry to obtain the intermediate product;

[0047] Step B3: Disperse 1g of functionalized silica in 100g of deionized water. Under nitrogen atmosphere, add 3g of intermediate product and 2g of triethylamine solution in sequence. Then adjust the pH to 10, raise the temperature to 80℃, react for 7h, filter, wash, and dry to obtain grafted modified silica. The triethylamine solution is prepared by mixing triethylamine and deionized water in a mass ratio of 0.75:20.

[0048] Step B4: Disperse 0.8g of grafted modified silica and 0.75g of sodium alginate in 50mL of deionized water by ultrasonication for 30min. Then, add 10mL of glucono-delta-lactone solution under vigorous stirring to form a mixture. Pour the mixture into a mold and let it stand for 40min to form a gel. Then freeze-dry the gel at -60℃ for 48h to obtain the modified aerogel. The glucono-delta-lactone solution is prepared by mixing glucono-delta-lactone and deionized water at a ratio of 0.45g:10mL.

[0049] Step B5: Weigh the raw materials according to the weight parts, add 40 parts of polypropylene fiber, 25 parts of aramid fiber and 15 parts of polyester fiber into the pulper respectively, add deionized water to dissolve for 20 minutes, then beat with a light blade for 55 minutes until the fibers are completely dispersed, and the three fiber pulps are obtained. The mass percentage concentration of each fiber in the three fiber pulps is 1%.

[0050] Step B6: Transfer the three types of pulp to the mixing tank, add deionized water to prepare a mass percentage concentration of 0.5%, then add 1.5 mL of dispersant (carboxymethyl cellulose) and 1 wt% of modified aerogel and stir to form a mixed pulp. Then dehydrate, press, dry and hot press the mixed pulp on a mesh fabric, and then roll and cut it to obtain composite fiber paper.

[0051] Example 3

[0052] The insulating filler is prepared by the following steps:

[0053] 1.4 g of polyvinylpyrrolidone was dispersed in 160 mL of ethanol, and then 40 mL of xylene was added and mixed evenly. The mixture was then divided into two equal portions, labeled as solution A1 and solution A2. 0.03 mol of silicon carbide nanocrystals were added to 100 mL of solution A1 and dispersed evenly to obtain solution B. 0.04 mol of aluminum nitrate was added to 100 mL of solution A2 and mixed evenly to obtain solution C. Solutions B and C were mixed and sonicated for 20 min, and the pH was adjusted to 12. The mixture was then reacted at 35 °C for 60 min, allowed to stand and age for 3 days, centrifuged, washed, dried, and then calcined at 800 °C for 3.5 h to obtain the insulating filler.

[0054] The preparation method of composite fiber paper includes the following steps:

[0055] Step B1: Mix 0.02 mol γ-aminopropyltriethoxysilane, 0.1 mol tetraethyl orthosilicate and 0.02 mol mercaptopropyltrimethoxysilane in 200 mL of deionized water, then add 0.6 mL of ammonia water and stir for 12 h. Filter, wash and dry to obtain functionalized silica.

[0056] Step B2: Disperse 0.1 mol 5-aminoisophthalic acid in 100 mL dimethylacetamide, add 20 mL triethylamine and 0.1 mol acryloyl chloride sequentially under an ice-water bath, heat to 60 °C and react for 4.5 h, then transfer to 100 mL deionized water at 10 °C and stir for 10 min, filter, wash and dry to obtain the intermediate product;

[0057] Step B3: Disperse 1.5g of functionalized silica in 100g of deionized water. Under nitrogen atmosphere, add 5g of intermediate product and 3g of triethylamine solution in sequence. Then adjust the pH to 10.2, raise the temperature to 85℃, react for 8h, filter, wash, and dry to obtain grafted modified silica. The triethylamine solution is prepared by mixing triethylamine and deionized water at a mass ratio of 1:20.

[0058] Step B4: Disperse 1.2g of grafted modified silica and 1g of sodium alginate in 50mL of deionized water by ultrasonication for 30min. Then, add 10mL of glucono-delta-lactone solution under vigorous stirring to form a mixture. Pour the mixture into a mold and let it stand for 50min to form a gel. Then freeze-dry the gel at -60℃ for 48h to obtain the modified aerogel. The glucono-delta-lactone solution is prepared by mixing glucono-delta-lactone and deionized water at a ratio of 0.6g:10mL.

[0059] Step B5: Weigh the raw materials according to the weight parts, add 45 parts of polypropylene fiber, 30 parts of aramid fiber and 20 parts of polyester fiber into the pulper respectively, add deionized water to dissolve for 25 minutes, then use a light blade to pulp for 60 minutes until the fibers are completely dispersed, and the three fiber pulps are obtained. The mass percentage concentration of each fiber in the three fiber pulps is 1.5%.

[0060] Step B6: Transfer the three types of pulp to the mixing tank, add deionized water to prepare a mass percentage concentration of 0.7%, then add 2 mL of 1.5 wt% dispersant (carboxymethyl cellulose) and 35 parts of modified aerogel and stir to form a mixed pulp. Then dehydrate, press, dry and hot press the mixed pulp on a mesh fabric, and then roll and cut it to obtain composite fiber paper.

[0061] Example 4

[0062] A dry cell battery separator paper consists of two parts: a composite fiber paper prepared in Example 1 and a reinforcing pulp coated on the surface of the composite fiber paper.

[0063] The reinforcing slurry was prepared by mixing and stirring 2 parts of the insulating filler prepared in Example 1, 25 parts of polyacrylic acid emulsion, and 50 parts of deionized water.

[0064] The preparation method includes the following steps: uniformly coating the reinforcing slurry onto the surface of the composite fiber paper prepared in Example 1, with a coating thickness of 0.15 mm, and drying to obtain the dry cell separator paper.

[0065] Example 5

[0066] A dry cell battery separator paper consists of two parts: a composite fiber paper prepared in Example 2 and a reinforcing pulp coated on the surface of the composite fiber paper.

[0067] The reinforcing slurry was prepared by mixing 3.5 parts of the insulating filler prepared in Example 2, 30 parts of polyacrylic acid emulsion, and 70 parts of deionized water.

[0068] The preparation method includes the following steps: uniformly coating the reinforcing slurry onto the surface of the composite fiber paper prepared in Example 2, with a coating thickness of 0.17 mm, and drying to obtain the dry cell separator paper.

[0069] Example 6

[0070] A dry cell battery separator paper consists of two parts: a composite fiber paper prepared in Example 3 and a reinforcing pulp coated on the surface of the composite fiber paper.

[0071] The reinforcing slurry was prepared by mixing and stirring 5 parts of the insulating filler prepared in Example 3, 35 parts of polyacrylic acid emulsion, and 80 parts of deionized water.

[0072] The preparation method includes the following steps: uniformly coating the reinforcing slurry onto the surface of the composite fiber paper prepared in Example 3, with a coating thickness of 0.2 mm, and drying to obtain the dry cell separator paper.

[0073] Comparative Example 1

[0074] This comparative example is a diaphragm paper, which differs from Example 5 in that alumina is used instead of the reinforcing filler prepared in Example 2, while all other aspects are the same.

[0075] Comparative Example 2

[0076] This comparative example is a diaphragm paper, which differs from Example 5 in that it uses fiber paper instead of the composite fiber paper prepared in Example 2, while all other aspects are the same.

[0077] Fiber paper is prepared by the following steps:

[0078] Step A1: Weigh the raw materials according to the weight parts, add 45 parts of polypropylene fiber, 30 parts of aramid fiber and 20 parts of polyester fiber into the pulper respectively, add deionized water to dissolve for 25 minutes, then use a light blade to pulp for 60 minutes until the fibers are completely dispersed, and the three fiber pulps are obtained. The mass percentage concentration of each fiber in the three fiber pulps is 1.5%.

[0079] Step A2: Transfer the three types of pulp to the mixing tank, add deionized water to prepare a mass percentage concentration of 0.7%, then add 2 mL of 1.5 wt% dispersant (carboxymethyl cellulose) and 35 parts of modified aerogel and stir to form a mixed pulp. Then dehydrate, press, dry and hot press the mixed pulp on a mesh fabric, and then roll and cut it to obtain fiber paper.

[0080] The separator papers prepared in Examples 4-6 and Comparative Examples 1-2 were equilibrated for 24 hours under quasi-constant temperature and humidity conditions (23±1)℃ and (50±2)% relative humidity for performance testing.

[0081] Basis weight test: The test shall be conducted in accordance with GB / T 451.2-2002 "Determination of basis weight of paper and paperboard";

[0082] Tensile strength test: GB / T 12914-2018 "Determination of tensile strength of paper and paperboard";

[0083] Porosity test: The liquid absorption method was used. After the membrane paper was dried in an oven for 12 hours to completely remove the moisture, a sample with a side length of 20 mm was cut and the mass μ0 was weighed. The sample was then soaked in n-butanol for 6 hours and then taken out. After the excess liquid on the surface was absorbed with filter paper, its mass μ was weighed. ρ1 is the density of the dried paper sample and ρ2 is the density of n-butanol. The porosity was calculated as (μ0-μ)*ρ1 / (ρ1μ+(ρ1-ρ2)*μ0)*100%.

[0084] Alkali absorption rate test: Dry the diaphragm paper in an oven for 12 hours to completely remove moisture, cut a sample with a side length of 20 mm, and weigh it as m1. Soak the diaphragm paper in the electrolyte for 6 hours, take it out, wipe off the excess electrolyte on the surface with filter paper, and weigh the sample as m2. Calculate the liquid absorption rate γ = (m2-m1)m1*100%.

[0085] Contact angle test: Using a contact angle measuring instrument, a drop of electrolyte is dropped on the surface of the separator paper, and the contact angle is measured within 10 seconds to characterize the electrolyte wettability of the separator paper;

[0086] The test results are shown in the table below:

[0087]

[0088]

[0089] As can be seen from the table above, the diaphragm paper prepared by this invention, after testing for basis weight, tensile strength, porosity, alkali absorption rate, and contact angle, has a basis weight of 38.4 g / m³. 2 -39.2g / m 2 Within the specified range, the tensile index is between 35.6 N·m / g and 36.3 N·m / g, the porosity is between 53% and 56%, the alkali absorption rate is between 238.3% and 252.1%, and the contact angle is between 80.6° and 82.1°, indicating that this separator paper has good application prospects in dry batteries.

[0090] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. A dry cell separator paper, characterized by, The composite fiber paper is composed of a composite fiber paper and a reinforcing slurry coated on the surface of the composite fiber paper; The reinforcing slurry is obtained by mixing and stirring 2-5 parts of insulating filler, 25-35 parts of polyacrylic acid emulsion and 50-80 parts of deionized water; The insulating filler is prepared by the following steps: Polyvinylpyrrolidone is dispersed in ethanol, then xylene is added and uniformly mixed, and the mixture is evenly divided into two parts, which are denoted as solution A1 and solution A2, respectively; silicon carbide nanowhiskers are added to solution A1 and uniformly dispersed to obtain solution B; aluminum nitrate is added to solution A2 and uniformly mixed to obtain solution C; solution B and solution C are mixed, ultrasonically treated for 10-20 min, and adjusted to pH 7-12, and then continuously reacted at 15-35℃ for 40-60 min, and then aged for 2-3 days, centrifuged, washed, dried, and then calcined at 600-800℃ for 1.5-3.5 h to obtain the insulating filler; The preparation method of the composite fiber paper comprises the following steps: Step B1: gamma-aminopropyltriethoxysilane, tetraethyl orthosilicate and mercaptopropyltrimethoxysilane are mixed in deionized water, then ammonia water is added and stirred for 8-12 h, and then filtered, washed and dried to obtain functionalized silicon dioxide; Step B2: 5-aminoisophthalic acid is dispersed in dimethylacetamide, and then triethylamine and acryloyl chloride are added in sequence under ice water bath, and then the temperature is increased to 40-60℃ and reacted for 3.5-4.5 h, and then the mixture is transferred to deionized water at 10℃ and stirred for 10 min, and then filtered, washed and dried to obtain an intermediate product; Step B3: the functionalized silicon dioxide is dispersed in deionized water, and then the intermediate product and triethylamine solution are added in sequence under nitrogen condition, and then the pH is adjusted to 9.8-10.2, the temperature is increased to 75-85℃, and then the mixture is reacted for 6-8 h, and then filtered, washed and dried to obtain grafted modified silicon dioxide; Step B4: the grafted modified silicon dioxide and sodium alginate are ultrasonically dispersed in deionized water for 30 min, and then a glucose lactone solution is added under vigorous stirring to form a mixed solution, and then the mixed solution is poured into a mold and left to stand for 30-50 min to form a gel, and then the gel is freeze-dried at-60℃ for 48 h to obtain a modified aerogel; Step B5: the raw materials are weighed according to the weight parts, and then 35-45 parts of polypropylene fiber, 20-30 parts of aramid fiber and 10-20 parts of polyester fiber are added into a beater respectively, de-bonded for 15-25 min by adding deionized water, and then beaten for 50-60 min by light knife, and then the fibers are completely dispersed to obtain three kinds of fiber slurries; Step B6: the three kinds of slurries are transferred to a pulp preparation tank, deionized water is added to prepare a mixed slurry with a mass percentage concentration of 0.3%-0.7%, and then 1-2 mL of 0.5-1.5 wt% dispersant and 25-35 parts of modified aerogel are added and stirred to uniformly mix, and then the mixed slurry is dehydrated on a screen cloth, pressed, dried, hot-pressed, wound into a roll, and cut to obtain the composite fiber paper.

2. A dry cell separator paper according to claim 1, wherein The ratio of polyvinylpyrrolidone, ethanol and dimethylbenzene in the insulating filler solution A1 and solution A2 is 0.6-1.4g:160mL:40mL, the concentration of silicon carbide nanowhisker in solution B is 0.1-0.3mol / L, and the concentration of aluminum nitrate in solution C is 0.2-0.4mol / L.

3. A dry cell separator paper according to claim 1, wherein The ratio of γ-aminopropyltriethoxysilane, tetraethyl orthosilicate, mercaptopropyltrimethoxysilane, deionized water and ammonia in step B1 is 0.005-0.02mol:0.04-0.1mol:0.01-0.02mol:200mL:0.3-0.6mL.

4. A dry cell separator paper according to claim 1, wherein The ratio of 5-aminoisophthalic acid, dimethylacetamide, triethylamine, acryloyl chloride and deionized water in step B2 is 0.05-0.1mol:100mL:10-20mL:0.05-0.1mol:100mL.

5. A dry cell separator paper according to claim 1, wherein The ratio of functionalized silica, deionized water, intermediate product and triethylamine solution in step B3 is 0.5-1.5:100:1-5:1-3, and the triethylamine solution is prepared by mixing triethylamine and deionized water at a mass ratio of 0.5-1:

20.

6. A dry cell separator paper according to claim 1, wherein The ratio of grafted modified silica, sodium alginate, deionized water and gluconolactone solution in step B4 is 0.4-1.2g:0.5-1g:50mL:10mL, and the gluconolactone solution is prepared by mixing gluconolactone and deionized water at a ratio of 0.3-0.6g:10mL.

7. A dry cell separator paper according to claim 1, wherein In step B5, the mass percentage concentration of each fiber in the three fiber slurries is 0.5%-1.5%.

8. A method of producing the dry cell separator paper according to any one of claims 1 to 7, characterized by, The steps include: The reinforcing slurry is uniformly coated on the surface of the composite fiber paper, the coating thickness is 0.15-0.2mm, and the paper is dried to obtain the dry battery separator paper. The steps include: The reinforcing slurry is uniformly coated on the surface of the composite fiber paper, the coating thickness is 0.15-0.2mm, and the paper is dried to obtain the dry battery separator paper.

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