阅读说明：本技术 一种SiO2-聚甲基丙烯酸甲酯-聚偏氟乙烯的隔膜的制法 (SiO (silicon dioxide)2Method for preparing diaphragm of-polymethyl methacrylate-polyvinylidene fluoride ) 是由 俞中毅 于 2020-12-01 设计创作，主要内容包括：本发明涉及锂离子电池隔膜技术领域,且公开了一种SiO-2-聚甲基丙烯酸甲酯-聚偏氟乙烯的隔膜,乙烯砜与介孔二氧化硅纳米空心球发生加成反应,得到烯基化介孔二氧化硅纳米空心球,在碱性环境中,得到含烯基的聚偏氟乙烯,二者与甲基丙烯酸甲酯共聚,得到SiO-2-聚甲基丙烯酸甲酯-聚偏氟乙烯的隔膜,介孔二氧化硅纳米空心球具有超高的比表面积,提高离子电导率,增强隔膜的机械强度,减小与电解液的接触角,增大吸液率,聚甲基丙烯酸甲酯增加与电解液的亲和性,提高离子电导率,静电纺丝使隔膜呈三维网状结构,具有超高的比表面积和孔隙率,增大与电解液的接触面积,赋予隔膜优异的离子电导率、机械强度、对电解液的亲和性。(The invention relates to the technical field of lithium ion battery diaphragms and discloses a SiO 2 A diaphragm of polymethyl methacrylate-polyvinylidene fluoride, the addition reaction of vinyl sulfone and the mesoporous silica nano hollow sphere is carried out,obtaining the alkenyl mesoporous silica hollow nanospheres, obtaining the polyvinylidene fluoride containing the alkenyl in the alkaline environment, and copolymerizing the polyvinylidene fluoride and the methyl methacrylate to obtain the SiO 2 The mesoporous silica hollow nanospheres have an ultrahigh specific surface area, the ionic conductivity is improved, the mechanical strength of the diaphragm is enhanced, the contact angle with an electrolyte is reduced, the liquid absorption rate is increased, the affinity of the polymethyl methacrylate with the electrolyte is improved, the ionic conductivity is improved, the diaphragm is in a three-dimensional net structure due to electrostatic spinning, the specific surface area and the porosity are ultrahigh, the contact area with the electrolyte is increased, and the diaphragm is endowed with excellent ionic conductivity, mechanical strength and affinity to the electrolyte.)

1. SiO (silicon dioxide)₂-a polymethylmethacrylate-polyvinylidene fluoride membrane characterized in that: the SiO₂The preparation method of the diaphragm of polymethyl methacrylate-polyvinylidene fluoride comprises the following steps:

(1) adding methanol and hexadecyl trimethyl ammonium bromide into deionized water, placing the deionized water into a magnetic stirring device, uniformly stirring, adding a sodium hydroxide aqueous solution and a methyl alcohol solution of tetraethoxysilane, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the tetraethoxysilane is 70-80:1.5-2:100, uniformly stirring, sealing a bottle opening, carrying out stirring reaction for 6-18h, freezing and freeze-drying the solution, placing the dried product into a muffle furnace, and calcining for 2-4h at 460-500 ℃ to obtain the mesoporous silica nano hollow sphere;

(2) adding vinyl sulfone and triphenylphosphine into acetonitrile, stirring uniformly, adding the mesoporous silica hollow nanospheres, reacting for 2-4h at 45-55 ℃, washing and drying to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding potassium hydroxide and polyvinylidene fluoride into deionized water, stirring uniformly, quickly adding ethanol, stirring for reacting for 20-40min, performing suction filtration, washing and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding polyvinylidene fluoride containing alkenyl into N, N-dimethylformamide, stirring at 60-80 deg.C, adding alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azodiisobutyronitrile in nitrogen atmosphere, and continuously stirring for reaction for 6-18h to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂The flow rate of spinning solution in the spinning process is 2-3mL/h, the receiving distance is 15-20cm, and the SiO is obtained by vacuum drying₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

2. An SiO as claimed in claim 1₂-a polymethylmethacrylate-polyvinylidene fluoride membrane characterized in that: the magnetic stirring device in the step (1) comprises a main body, wherein a control module is movably connected to the right side of the bottom of the main body, a motor is movably connected to the middle of the bottom of the main body, a turntable is movably connected to the top of the motor, a magnet is movably connected to the left side of the turntable, a partition plate is movably connected to the middle of the main body, a heating plate is movably connected to the top of the partition plate, a positioning ring is movably connected to the middle of the main body, and a beaker is movably connected to.

3. An SiO as claimed in claim 1₂-a polymethylmethacrylate-polyvinylidene fluoride membrane characterized in that: in the step (2), the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 20-60:1-3: 100.

4. An SiO as claimed in claim 1₂-a polymethylmethacrylate-polyvinylidene fluoride membrane characterized in that: the mass ratio of the potassium hydroxide to the polyvinylidene fluoride in the step (3) is 5-10: 100.

5. An SiO as claimed in claim 1₂-a polymethylmethacrylate-polyvinylidene fluoride membrane characterized in that: the mass ratio of the alkenyl-containing polyvinylidene fluoride, the alkenyl mesoporous silica hollow nanospheres, the methyl methacrylate and the azodiisobutyronitrile in the step (4) is 100:4-10:20-30: 0.3-0.6.

Technical Field

The invention relates to the technical field of lithium ion battery diaphragms, in particular to SiO₂A method for producing a polymethyl methacrylate-polyvinylidene fluoride separator.

Background

The lithium ion battery has the advantages of high energy density, long cycle life and the like, is widely applied to the fields of electronic equipment, mobile power supplies, electric automobiles and the like, and the diaphragm is also called as a third electrode which is an important component in the lithium ion battery and is used for preventing the battery from short circuit, isolating the positive electrode and the negative electrode and the like, so that the safety and the electrochemical performance of the battery are influenced, but the existing liquid electrolyte diaphragm has the problem of liquid leakage.

The polymer electrolyte membrane is used for replacing a liquid electrolyte membrane to solve the problem of liquid leakage, and the main materials comprise polyvinylidene fluoride, poly (hexamethylene oxide), polyacrylonitrile and the like, wherein the polyvinylidene fluoride has good electrochemical stability and can be used for preparing the polymer electrolyte membrane, but the crystallinity of the polyvinylidene fluoride is high, the affinity to the liquid electrolyte is poor, so that the ionic conductivity is low, the mechanical strength is to be improved, the poly (vinylidene fluoride) needs to be modified, the interface stability between polymethyl methacrylate and electrodes is good, a large amount of liquid electrolyte can be adsorbed, the ionic conductivity is high, but the mechanical strength is low, the structural stability is poor, and the nano SiO is added₂Can improve the affinity, ionic conductivity and mechanical strength to electrolyte and inhibit the thermal shrinkage of the diaphragm, so that SiO is adopted₂Polymethyl methacrylate-polyvinylidene fluoride to solve the above problems.

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides SiO₂The preparation method of the polyvinylidene fluoride-polymethyl methacrylate diaphragm solves the problems that the polyvinylidene fluoride diaphragm has poor affinity to liquid electrolyte, low ionic conductivity and low mechanical strength to be improved.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: SiO (silicon dioxide)₂-a separator of polymethyl methacrylate-polyvinylidene fluoride, said SiO₂The preparation method of the diaphragm of polymethyl methacrylate-polyvinylidene fluoride comprises the following steps:

(1) adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, adding a sodium hydroxide aqueous solution and a methanol solution of tetraethoxysilane, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the tetraethoxysilane is 70-80:1.5-2:100, uniformly stirring, sealing the bottle mouth, carrying out stirring reaction for 6-18h, freezing and freeze-drying the solution, placing the dried product into a muffle furnace, and calcining for 2-4h at 460-500 ℃ to obtain the mesoporous silica nano hollow sphere;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, reacting for 2-4h at 45-55 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, uniformly stirring, quickly adding ethanol, stirring for reacting for 20-40min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and vinyl-containing polyvinylidene fluoride into a reaction bottle, uniformly stirring at 60-80 ℃, adding the alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azodiisobutyronitrile in a nitrogen atmosphere, and continuously stirring for reacting for 6-18h to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂The flow rate of spinning solution in the spinning process is 2-3mL/h, the receiving distance is 15-20cm, and the SiO is obtained by vacuum drying₂Of polymethyl methacrylate-polyvinylidene fluorideA diaphragm.

Preferably, step (1) middle magnetic stirring device includes the main part, and the right side swing joint of main part bottom has control module, and the centre swing joint of main part bottom has the motor, and the top swing joint of motor has the carousel, and the left side swing joint of carousel has magnet, and the centre swing joint of main part has the baffle, and the top swing joint of baffle has the heating plate, and the centre swing joint of main part has the holding ring, and the centre swing joint of holding ring has the beaker.

Preferably, the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres in the step (2) is 20-60:1-3: 100.

Preferably, the mass ratio of the potassium hydroxide to the polyvinylidene fluoride in the step (3) is 5-10: 100.

Preferably, the mass ratio of the alkenyl-containing polyvinylidene fluoride, the alkenyl mesoporous silica hollow nanospheres, the methyl methacrylate and the azodiisobutyronitrile in the step (4) is 100:4-10:20-30: 0.3-0.6.

(III) advantageous technical effects

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

the SiO₂A polymethyl methacrylate-polyvinylidene fluoride membrane, in an alkaline environment, cetyl trimethyl ammonium bromide is used as a template agent, hydrolyzing tetraethoxysilane in the stirring process, freezing and calcining to obtain mesoporous silica nano hollow spheres containing hydroxyl, under the action of a catalyst triphenylphosphine, alkenyl on the vinyl sulfone and hydroxyl on the mesoporous silica hollow nanospheres are subjected to addition reaction, alkenyl groups are introduced, and the alkenylated mesoporous silica hollow nanospheres are obtained, in an alkaline environment, carrying out elimination reaction on H atoms and F atoms on the polyvinylidene fluoride to generate alkenyl groups to obtain polyvinylidene fluoride containing alkenyl, under the action of a catalyst azodiisobutyronitrile, the alkenyl mesoporous silica hollow nanospheres, the alkenyl polyvinylidene fluoride and the methyl methacrylate are copolymerized to obtain the covalently grafted SiO.₂Electrostatic spinning of a poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution to obtain SiO₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

The SiO₂The diaphragm of polymethyl methacrylate-polyvinylidene fluoride, the three are covalently grafted, so that the mesoporous silica hollow nanospheres and the polymethyl methacrylate are uniformly dispersed on the polyvinylidene fluoride substrate, the agglomeration of the silica hollow nanospheres is reduced, the mesoporous silica hollow nanospheres have ultra-high specific surface area, the contact area with electrolyte is increased, lithium ion migration channels are increased, the diffusion path of lithium ions is shortened, the ionic conductivity is improved, the uniformly dispersed silica has high mechanical strength, the mechanical strength of the diaphragm is effectively enhanced, the contact angle with the electrolyte is reduced, the liquid absorption rate is increased, the uniformly dispersed silica endows the diaphragm with excellent thermal stability, short circuit or explosion caused by overhigh temperature is effectively avoided, the safety of the battery is improved, and the uniformly dispersed polymethyl methacrylate prevents the crystallization of the polyvinylidene fluoride, the crystallinity of polyvinylidene fluoride is reduced, the affinity with electrolyte is increased, the transmission of lithium ions is accelerated, the compatibility of polymethyl methacrylate and electrolyte is good, the diaphragm can adsorb more liquid electrolyte, the ionic conductivity is further improved, the cycle performance and the capacity retention rate of the lithium ion battery are improved, meanwhile, the diaphragm is in a three-dimensional net structure through electrostatic spinning, the specific surface area and the porosity are ultrahigh, the contact area with the electrolyte is increased, and SiO is endowed with₂The separator of polymethyl methacrylate-polyvinylidene fluoride is excellent in ion conductivity, mechanical strength, and affinity for an electrolyte.

Drawings

FIG. 1 is a schematic front view of a magnetic stirring apparatus;

FIG. 2 is a schematic top view of the magnetic stirring apparatus;

fig. 3 is a schematic view of a turntable structure.

1. A main body; 2. a control module; 3. a motor; 4. a turntable; 5. a magnet; 6. a partition plate; 7. heating the plate; 8. a positioning ring; 9. and (4) a beaker.

Detailed Description

To achieve the above object, the present invention provides the following embodiments and examples: SiO (silicon dioxide)₂-polymethylmethacrylate-polyvinylidene fluoride diaphragm, SiO₂The preparation method of the diaphragm of polymethyl methacrylate-polyvinylidene fluoride comprises the following steps:

(1) adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 70-80:1.5-2:100, uniformly stirring, then placing the dried product in a muffle furnace, and calcining for 2-4h at 460-500 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 20-60:1-3:100, reacting for 2-4h at the temperature of 45-55 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 5-10:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 20-40min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, stirring at 60-80 deg.C, adding alkenyl mesoporous silica hollow nanospheres and methyl in nitrogen atmosphereMethyl acrylate and azodiisobutyronitrile, wherein the mass ratio of the alkenyl-containing polyvinylidene fluoride to the alkenyl mesoporous silica hollow nanospheres to the methyl methacrylate to the azodiisobutyronitrile is 100:4-10:20-30:0.3-0.6, and the stirring reaction is continued for 6-18h to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂The flow rate of spinning solution in the spinning process is 2-3mL/h, the receiving distance is 15-20cm, and the SiO is obtained by vacuum drying₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

Example 1

(1) Adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 70:1.5:100, uniformly stirring, sealing a bottle opening, stirring for 6, calcining for 2 hours at 460 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 20:1:100, reacting for 2 hours at 45 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 5:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 20min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, uniformly stirring at 60 ℃, adding the alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azodiisobutyronitrile in a nitrogen atmosphere, wherein the mass ratio of the alkenyl polyvinylidene fluoride to the alkenyl mesoporous silica hollow nanospheres to the methyl methacrylate to the azodiisobutyronitrile is 100:4:20:0.3, and continuously stirring for reacting for 6 hours to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂The flow rate of spinning solution in the spinning process is 2mL/h, the receiving distance is 15cm, and the SiO is obtained by vacuum drying₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

Example 2

(1) Adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 75:1.8:100, uniformly stirring, sealing a bottle opening, stirring for 12, calcining for 3h at 480 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 40:2:100, reacting for 3 hours at 50 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 7.5:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 30min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, uniformly stirring at 70 ℃, adding the alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azobisisobutyronitrile in the nitrogen atmosphere, wherein the mass ratio of the alkenyl polyvinylidene fluoride to the alkenyl mesoporous silica hollow nanospheres to the methyl methacrylate to the azobisisobutyronitrile is 100:7:25:0.5, and continuously stirring and reacting for 12 hours to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂A spinning solution flow rate of 2.5mL/h and a receiving distance of 17.5cm in the spinning process of the polymethyl methacrylate-polyvinylidene fluoride fiber membrane, and drying in vacuum to obtain SiO₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

Example 3

(1) Adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 73:1.7:100, uniformly stirring, sealing a bottle opening, stirring for 10, calcining for 3 hours at 490 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 35:1.7:100, reacting for 3 hours at 55 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 8:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 25min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, uniformly stirring at 65 ℃, adding the alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azobisisobutyronitrile in the nitrogen atmosphere, wherein the mass ratio of the alkenyl polyvinylidene fluoride to the alkenyl mesoporous silica hollow nanospheres to the methyl methacrylate to the azobisisobutyronitrile is 100:6:24:0.4, and continuously stirring and reacting for 10 hours to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂A spinning solution flow rate of 2.4mL/h and a receiving distance of 17cm in the spinning process of the polymethyl methacrylate-polyvinylidene fluoride fiber membrane, and drying in vacuum to obtain SiO₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

Example 4

(1) Adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 80:2:100, uniformly stirring, sealing a bottle opening, stirring for 18, calcining for 4 hours at 500 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 60:3:100, reacting for 4 hours at 55 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 10:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 40min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, stirring uniformly at 80 ℃, adding the alkenyl mesoporous silica hollow nanospheres, methyl methacrylate and azodiisobutyronitrile in a nitrogen atmosphere, wherein the mass ratio of the alkenyl polyvinylidene fluoride to the alkenyl mesoporous silica hollow nanospheres to the methyl methacrylate to the azodiisobutyronitrile is 100:10:20:0.6, and continuously stirring for 18 hours to obtain SiO₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Poly (methyl methacrylate) -poly (vinylidene fluoride)Injecting the ethylene copolymer solution into a syringe, and preparing SiO by electrostatic spinning₂A spinning solution flow rate of 3mL/h and a receiving distance of 20cm in the spinning process of the polymethyl methacrylate-polyvinylidene fluoride fiber membrane, and drying in vacuum to obtain SiO₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

Comparative example 1

(1) Adding deionized water, methanol and hexadecyl trimethyl ammonium bromide into a reaction bottle, placing the reaction bottle into a magnetic stirring device, uniformly stirring, wherein the magnetic stirring device comprises a main body, the right side of the bottom of the main body is movably connected with a control module, the middle of the bottom of the main body is movably connected with a motor, the top of the motor is movably connected with a rotary disc, the left side of the rotary disc is movably connected with a magnet, the middle of the main body is movably connected with a partition plate, the top of the partition plate is movably connected with a heating plate, the middle of the main body is movably connected with a positioning ring, the middle of the positioning ring is movably connected with a beaker, adding a sodium hydroxide aqueous solution and a methanol solution of ethyl orthosilicate, wherein the mass ratio of the hexadecyl trimethyl ammonium bromide to the sodium hydroxide to the ethyl orthosilicate is 60:1:100, uniformly stirring, sealing a bottle opening, stirring for 12, calcining for 2h at 480 ℃ to obtain mesoporous silica hollow nanospheres;

(2) adding acetonitrile, vinyl sulfone and triphenylphosphine into a reaction bottle, uniformly stirring, adding the mesoporous silica hollow nanospheres, wherein the mass ratio of the vinyl sulfone to the triphenylphosphine to the mesoporous silica hollow nanospheres is 10:0.3:100, reacting for 4 hours at 50 ℃, washing with acetonitrile, and blow-drying with nitrogen to obtain the alkenylated mesoporous silica hollow nanospheres;

(3) adding deionized water, potassium hydroxide and polyvinylidene fluoride into a reaction bottle, wherein the mass ratio of the deionized water to the potassium hydroxide to the polyvinylidene fluoride is 2:100, uniformly stirring, quickly adding ethanol, stirring for reaction for 40min, performing suction filtration, washing with deionized water, and drying to obtain polyvinylidene fluoride containing alkenyl;

(4) adding N, N-dimethylformamide and polyvinylidene fluoride containing alkenyl into a reaction bottle, stirring uniformly at 60 ℃, and adding alkenyl mesoporous silicon dioxide sodium in nitrogen atmosphereThe method comprises the following steps of continuously stirring and reacting for 12 hours to obtain SiO, wherein the mass ratio of the hollow rice spheres, methyl methacrylate and azodiisobutyronitrile to the alkenyl-containing polyvinylidene fluoride, the alkenyl mesoporous silica hollow nanospheres, the methyl methacrylate and the azodiisobutyronitrile is 100:2:10:0.1₂-a polymethylmethacrylate-polyvinylidene fluoride copolymer solution;

(5) mixing SiO₂Injecting the poly (methyl methacrylate-poly (vinylidene fluoride)) copolymer solution into an injector, and preparing SiO by electrostatic spinning₂The flow rate of a spinning solution in the spinning process is 2.5mL/h, the receiving distance is 15cm, and the SiO is obtained by vacuum drying₂-a separator of polymethyl methacrylate-polyvinylidene fluoride.

The SiO obtained in the examples and comparative examples was tested using a RS-8010W type universal tester₂Tensile strength of the membranes of polymethyl methacrylate-polyvinylidene fluoride, test standard GB/T1040.3-2006.

The SiO 2-polymethyl methacrylate-polyvinylidene fluoride diaphragms obtained in the examples and the comparative examples are used as diaphragms, the positive and negative electrodes are steel sheets and lithium sheets, the diaphragms are assembled into a blocking battery in a glove box, and the ionic conductivity of the blocking battery is tested by a DH7000 type electrochemical workstation, wherein the test standard is GB/T36363-2018.

The contact angle of deionized water on the SiO 2-polymethyl methacrylate-polyvinylidene fluoride membranes obtained in examples and comparative examples was measured by using a SZ-CAMA1 contact angle meter, and the test standard was GB/T30447-2013.

Item	Example 1	Example 2	Example 3	Example 4	Comparative example 1
						Contact angle (°)	57.8	51.3	54.5	58.0	69.7