CN113991246A - Preparation method of battery diaphragm with high stability and long cycle life - Google Patents

Preparation method of battery diaphragm with high stability and long cycle life Download PDF

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CN113991246A
CN113991246A CN202111263872.3A CN202111263872A CN113991246A CN 113991246 A CN113991246 A CN 113991246A CN 202111263872 A CN202111263872 A CN 202111263872A CN 113991246 A CN113991246 A CN 113991246A
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polyimide
beating
cellulose
fiber membrane
solution
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朱莹
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Shanghai Mofang New Material Co ltd
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Shanghai Mofang New Material Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • Manufacturing & Machinery (AREA)
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  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Cell Separators (AREA)

Abstract

The invention discloses a preparation method of a battery diaphragm with high stability and long cycle life, which comprises the following steps: adding a certain amount of 4, 4-diaminodiphenyl ether, DMF and pyromellitic dianhydride into a three-neck flask, and reacting to prepare a polyamic acid solution; then reacting a certain amount of polyamic acid solution and polyimide resin powder with ascidian cellulose through the cross-linking effect of boric acid to obtain a solution; preparing a polyimide fiber membrane of the composite ascidian cellulose by adopting an electrostatic spinning technology, and drying the polyimide fiber membrane in an oven; then pulping and physically cutting off the dried polyimide fiber membrane; and adding a proper amount of additive into the beaten polyimide fibers, defibering in a defibering machine, and then making a certain amount of polyimide base material with certain strength by adopting a wet papermaking process to prepare the battery diaphragm paper.

Description

Preparation method of battery diaphragm with high stability and long cycle life
Technical Field
The invention belongs to the technical field of battery diaphragm preparation, and particularly relates to a preparation method of a battery diaphragm with high stability and long cycle life.
Background
The battery diaphragm is isolated between the anode and the cathode so as to prevent the physical contact of the two electrodes from causing the internal short circuit of the battery, and meanwhile, an ion transmission channel is provided, so that the free transfer of lithium ions during the charging and discharging of the battery is realized, and current is formed. The chemical performance of the battery separator has an important influence on the cycle performance, rate performance and safety performance of the battery, so that the performance of the battery is greatly dependent on the quality of the battery separator. The battery separator must have good uniformity and insulating properties, good mechanical strength, excellent electrolyte wettability and thermal stability.
Currently, battery separators can be classified into the following categories: polyolefin microporous membranes, nonwoven fabric membranes and inorganic composite membranes. The polyolefin microporous diaphragm has low price, good mechanical strength and electrolyte chemical stability, has closed pore performance when the internal temperature of the battery is overheated, can ensure the safety performance of the lithium secondary battery in normal use, but cannot ensure the safety performance of the battery when the temperature of the battery is too high, and the battery is overcharged or overdischarged. The commercial lithium ion battery diaphragm mainly adopts three materials, namely a polyethylene film, a polypropylene film or a PP/PE/PP three-layer composite film, and can reach the melting point of polyethylene when the temperature exceeds about 135 ℃. The non-woven fabric diaphragm is a porous membrane formed by fiber orientation or random arrangement, the application range of the diaphragm is mainly embodied in nickel-hydrogen and nickel-chromium batteries, and compared with the traditional Celgard diaphragm prepared by a dry method, the non-woven fabric diaphragm presents a three-dimensional pore structure which can effectively improve the performances of electrolyte liquid absorption rate, electrolyte liquid retention rate, air permeability and the like. The inorganic composite diaphragm is a porous composite film formed by coating a coating formed by an adhesive and inorganic nanoparticles on a diaphragm substrate, has excellent electrolyte wettability, can absorb and maintain a large amount of electrolyte, has certain help for prolonging the service life of a battery, and has excellent thermal dimensional stability, good cycle rate performance and safety performance under the condition of high temperature.
Polyimide (PI) fiber is a new type of insulating fiber material, and has attracted attention because of its excellent properties such as high temperature resistance, radiation resistance, and corrosion resistance. The polyimide fiber has good development and application in the fields of protection, reinforcement, high-temperature filtration and the like. The existence of aromatic heterocyclic ring structure with extremely high rigidity in the main chain of polyimide fiber molecule enables the polyimide fiber to have excellent high temperature resistance, low temperature resistance, corrosion resistance and excellent mechanical property. The polyimide molecule main chain contains a large number of imide rings, aromatic rings or heterocyclic rings, N ═ O bonds on the imide rings can be very high and have high rigidity, and the conjugated effect generated by the aromatic rings or the heterocyclic rings enables the intermolecular force to be large; the characteristics of the polyimide fiber with high strength and high modulus mainly depend on the uniaxial tension of the production process.
The sea squirt cellulose is a kind of cellulose produced by sea squirts of marine animals, exists in tunic of sea squirts, has a plurality of unique characteristics compared with some plant celluloses, is used for researching and developing novel special functional materials such as an energy-saving reflection film of the sea squirt cellulose, high-performance conductive paper of the sea squirt cellulose, spinning solution of the sea squirt cellulose and the like, has the molecular weight 2.5 times that of cotton fiber, and has the advantages of high strength, high mechanical property, good air permeability, no toxicity, no harm and the like.
At present, the heat stability of the diaphragm is poor due to the limitation of the properties of the materials, the thermal shrinkage phenomenon of the diaphragm can be generated due to the overhigh temperature of the battery, the safety performance of the lithium battery is damaged due to the direct contact of the anode and the cathode, and meanwhile, the poor wettability of the electrolyte of the diaphragm is not high, the absorption and the maintenance of the electrolyte with high capacity are not facilitated, and the cycle life of the lithium battery is not facilitated.
Disclosure of Invention
Aiming at the problems that the existing commercial diaphragm type polyolefin diaphragm has poor thermal stability due to the limitation of the properties of the materials, the thermal contraction phenomenon of the diaphragm can be generated due to the overhigh temperature of the battery, the direct contact of the anode and the cathode is caused, and the safety performance of the lithium battery is damaged, and the problems that the wetting property of the electrolyte of the diaphragm is not high, the electrolyte with high capacity is not easy to absorb and maintain, and the cycle life of the lithium battery is not easy exist, the invention aims to provide a preparation method of the battery diaphragm with high stability and long cycle life, and the technical scheme is as follows:
adding a certain amount of 4, 4-diaminodiphenyl ether, DMF and pyromellitic dianhydride into a three-neck flask, and reacting to prepare a polyamic acid solution; then reacting a certain amount of polyamic acid solution and polyimide resin powder with ascidian cellulose through the cross-linking effect of boric acid to obtain a solution; preparing a polyimide fiber membrane of the composite ascidian cellulose by adopting an electrostatic spinning technology, and drying the polyimide fiber membrane in an oven; then pulping and physically cutting off the dried polyimide fiber membrane; and adding a proper amount of additive into the beaten polyimide fibers, defibering in a defibering machine, and then making a certain amount of polyimide base material with certain strength by adopting a wet papermaking process to prepare the battery diaphragm paper.
Preferably, the additives used above are dispersants, reinforcing agents and adhesives.
The preparation method comprises the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.13-0.3 mol/L DMF solution, controlling the reaction temperature at 0-3 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask in 4 times during stirring, and continuing to react for 3.5 hours to obtain the polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1: 1.11-1.23: 15-20.
S2: adding the polyamic acid solution obtained in the step S1 and the polyimide resin powder into a container according to the weight ratio of 1: 0.03-0.06, ultrasonically stirring uniformly, then adding boric acid, mechanically stirring for 0.5-1 h, then adding sea squirt cellulose, heating to 50-70 ℃, and reacting for 0.5-3 h to obtain a solution.
S3: and (3) extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose.
S4: and (4) putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step (S3) into a Waele beater to carry out beating treatment, wherein the beating concentration is controlled to be 0.6-1.2%, the beating time is 4-6 h, and the beating pressure is 8-11 kg.
S5: putting the beaten polyimide fiber of the composite sea squirt cellulose in the step S4 into a defiberizing machine, adding a dispersant, a reinforcing agent and an adhesive, and then making paper by a wet papermaking process, wherein the quantitative amount is 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
Preferably, in the step S2, the particle size of the polyimide resin powder is 30 to 50 μm.
Preferably, in step S2, the amount of boric acid added is about 0.2 to 0.3 times the mass of the polyamic acid solution, and the amount of ascidian cellulose added is about 0.06 to 0.1 times the mass of the polyamic acid solution.
Preferably, in the step S5, the weight ratio of the sea squirt cellulose-compounded polyimide fibers, the dispersant, the reinforcing agent and the adhesive is 30-50: 1:1.1: 0.7.
Preferably, in step S5, the dispersant, the reinforcing agent and the adhesive are toluene diisocyanate, DH-4 reinforcing agent and dimethylolpropionic acid, respectively.
Preferably, the Bulboli beater carries out beating treatment, the beating concentration is controlled to be 0.6-1.1%, the beating time is 4-5.5 hours, and the beating pressure is 8-11 kg.
The invention has the following beneficial effects:
(1) the battery diaphragm paper prepared by the preparation method has high liquid absorption rate which reaches 376 percent and is 4.58 times of that of a commercial Celgard membrane, and meanwhile, the diaphragm material overcomes the defects that the diaphragm electrolyte has low wettability and cannot absorb and maintain high-capacity electrolyte, and is beneficial to the cycle life of a lithium battery.
(2) The polyimide fiber does not have hydrogen bonds of natural fibers, the strength of the polyimide fiber is reduced after wet forming, the polyimide fiber and the sea squirt cellulose with high modulus are compounded to prepare the diaphragm paper, the strength and the rigidity of the diaphragm paper are improved, and the structure of the diaphragm paper is more stable in the process of cyclic charge and discharge of a battery.
(3) The sea squirt cellulose adopted by the invention is cellulose obtained from sea squirts which are marine organisms, and has strong hydrophilicity, and the prepared battery diaphragm paper has high liquid absorption rate, so that the battery performance can be improved.
(4) The invention adopts an electrostatic spinning method to prepare a polyimide fibrous membrane, polyimide resin powder is added into polyamic acid solution, and then boric acid and ascidian cellulose are added, wherein the boric acid is taken as a cross-linking agent to perform cross-linking reaction with a large amount of hydroxyl groups on the surface of the ascidian cellulose depending on the interface provided by the polyimide resin powder, then the boric acid is gradually decomposed in the electrostatic spinning process, and the ascidian cellulose conforms to the requirement of forming a membrane on the polyimide fiber. Then beating and defibering to cut the polyimide fiber, the two ends are crushed, the fiber length is uniform, the fiber can be dispersed uniformly, and the manufactured diaphragm paper has higher tensile strength.
Drawings
FIG. 1 is an SEM image of battery separator paper prepared in example 1 of the present invention;
FIG. 2 is a graph showing cycle characteristics of a separator paper for a battery prepared in example 1 of the present invention (example 1: triangle; comparative example 1: circle);
FIG. 3 is a graph showing rate performance of the separator paper for a battery prepared in example 1 of the present invention (example 1: triangle; comparative example 1: circle).
Detailed Description
The following examples are provided for the purpose of illustration, and the present invention is not limited to the following examples.
Example 1
A preparation method of a battery diaphragm with high stability and long cycle life specifically comprises the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.13mol/L DMF solution, controlling the reaction temperature at 0 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask by 4 times in the stirring process, and continuing to react for 3.5 hours to obtain the polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1:1.11: 15.
S2: adding the polyamic acid solution obtained in the step S1 and polyimide resin powder with the particle size of 30-50 mu m according to the weight ratio of 1:0.03 into a container, ultrasonically stirring uniformly, adding boric acid, mechanically stirring for 0.5h, adding ascidian cellulose, heating to 50 ℃ and reacting for 0.5h to obtain a solution, wherein the adding amount of the boric acid is about 0.2 times of the mass of the polyamic acid solution, and the adding amount of the ascidian cellulose is about 0.06 times of the mass of the polyamic acid solution.
S3: and (3) extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose.
S4: and (4) putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step (S3) into a Wally beating machine for beating, wherein the beating concentration is controlled to be 0.6%, the beating time is 4h, and the beating pressure is 8 kg.
S5: putting the beaten polyimide fiber of the composite ecteinascidin cellulose in the step S4 into a defiberizer, adding toluene diisocyanate, DH-4 reinforcing agent and dimethylolpropionic acid, wherein the weight ratio of the polyimide fiber of the composite ecteinascidin cellulose to the dispersing agent to the reinforcing agent to the adhesive is 30:1:1.1:0.7, and then making paper by a wet papermaking process with the quantitative of 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
Example 2
A preparation method of a battery diaphragm with high stability and long cycle life specifically comprises the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.3mol/L DMF solution, controlling the reaction temperature at 3 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask by 4 times in the stirring process, and continuing to react for 3.5 hours to obtain the polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1:1.23: 20.
S2: adding the polyamic acid solution obtained in the step S1 and polyimide resin powder with the particle size of 30-50 mu m according to the weight ratio of 1:0.06 into a container, ultrasonically stirring uniformly, adding boric acid, mechanically stirring for 1h, then adding sea squirt cellulose, heating to 70 ℃, and reacting for 0.5-3 h to obtain a solution, wherein the adding amount of the boric acid is about 0.3 times of the mass of the polyamic acid solution, and the adding amount of the sea squirt cellulose is about 0.1 times of the mass of the polyamic acid solution.
S3: and (3) extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose.
S4: and (4) putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step (S3) into a Wally beating machine for beating, wherein the beating concentration is controlled to be 1.2%, the beating time is 6h, and the beating pressure is 11 kg.
S5: putting the beaten polyimide fiber of the composite ecteinascidin cellulose in the step S4 into a defiberizer, adding toluene diisocyanate, DH-4 reinforcing agent and dimethylolpropionic acid, wherein the weight ratio of the polyimide fiber of the composite ecteinascidin cellulose to the dispersing agent to the reinforcing agent to the adhesive is 50:1:1.1:0.7, and then making paper by a wet papermaking process, wherein the quantitative amount is 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
Example 3
A preparation method of a battery diaphragm with high stability and long cycle life specifically comprises the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.22mol/L DMF solution, controlling the reaction temperature at 1 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask by 4 times in the stirring process, and continuing to react for 3.5 hours to obtain the polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1:1.16: 17.
S2: adding the polyamic acid solution obtained in the step S1 and polyimide resin powder with the particle size of 30-50 mu m according to the weight ratio of 1:0.04 into a container, ultrasonically stirring uniformly, adding boric acid, mechanically stirring for 1h, adding sea squirt cellulose, heating to 60 ℃ and reacting for 1.5h to obtain a solution, wherein the adding amount of the boric acid is about 0.2 times of the mass of the polyamic acid solution, and the adding amount of the sea squirt cellulose is about 0.08 times of the mass of the polyamic acid solution.
S3: and (3) extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose.
S4: and (5) putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step (S3) into a Wally beating machine for beating, wherein the beating concentration is controlled to be 0.9%, the beating time is 5h, and the beating pressure is 9 kg.
S5: putting the beaten polyimide fiber of the composite ecteinascidin cellulose in the step S4 into a defiberizer, adding toluene diisocyanate, DH-4 reinforcing agent and dimethylolpropionic acid, wherein the weight ratio of the polyimide fiber of the composite ecteinascidin cellulose to the dispersing agent to the reinforcing agent to the adhesive is 40:1:1.1:0.7, and then making paper by a wet papermaking process, wherein the quantitative amount is 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
Example 4
A preparation method of a battery diaphragm with high stability and long cycle life specifically comprises the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.28mol/L DMF solution, controlling the reaction temperature at 2 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask by 4 times in the stirring process, and continuing to react for 3.5 hours to obtain the polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1:1.21: 19.
S2: adding the polyamic acid solution obtained in the step S1 and polyimide resin powder with the particle size of 45 mu m according to the weight ratio of 1:0.05 into a container, ultrasonically stirring the mixture evenly, then adding boric acid, mechanically stirring the mixture for 1 hour, then adding sea squirt cellulose, heating the mixture to 65 ℃ and reacting the mixture for 2.5 hours to obtain a solution, wherein the adding amount of the boric acid is about 0.3 times of the mass of the polyamic acid solution, and the adding amount of the sea squirt cellulose is about 0.09 times of the mass of the polyamic acid solution.
S3: and (3) extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose.
S4: and (4) putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step (S3) into a Wally beating machine for beating, wherein the beating concentration is controlled to be 1.1%, the beating time is 6h, and the beating pressure is 10 kg.
S5: putting the beaten polyimide fiber of the composite sea squirt cellulose in the step S4Adding toluene diisocyanate, a DH-4 reinforcing agent and dimethylolpropionic acid into a fiber fluffer, wherein the weight ratio of the polyimide fiber of the composite ecteinascidin cellulose to the dispersing agent to the reinforcing agent to the adhesive is 45:1:1.1:0.7, and then adopting a wet papermaking process to manufacture paper, wherein the quantitative amount is 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
Comparative example 1
Prepared according to the preparation method described in example 3 of patent document (CN 109295512B).
Performance test experiments:
the performance tests including contact angle, liquid absorption rate, and heat shrinkage rate were performed on a commercial separator of Celgard2400, a separator provided in comparative example 1, and a separator provided in example 1, and the results are shown in table 1. And electrical property tests were performed under the same cell conditions using the separator paper prepared in example 1 and the separator of comparative example 1.
Table 1. results of performance testing:
Figure BDA0003323574800000071
as can be seen from table 1, the contact angle of the separator prepared in example 1 was 17.3 °, and the liquid absorption rate thereof reached 376%, which was better than those of the separators prepared in Celgard2400 commercial membrane and comparative example 1, while the separator material prepared in example 1 had higher charge capacity as can be seen from fig. 2 and 3.
It should be noted that the diaphragms prepared in embodiments 2 to 4 of the present invention have the same or similar performance as the diaphragm material prepared in embodiment 1, and are not described in detail herein.

Claims (6)

1. A preparation method of a battery diaphragm with high stability and long cycle life is characterized by comprising the following steps:
s1: adding 4, 4-diaminodiphenyl ether into a three-neck flask, then adding 0.13-0.3 mol/L DMF solution, controlling the reaction temperature at 0-3 ℃ under nitrogen, adding pyromellitic dianhydride into the three-neck flask in 4 times during stirring, and continuing to react for 3.5 hours to obtain a polyamic acid solution, wherein the mass ratio of the 4, 4-diaminodiphenyl ether, the pyromellitic dianhydride and the DMF solution is 1: 1.11-1.23: 15-20;
s2: adding the polyamic acid solution obtained in the step S1 and polyimide resin powder into a container according to the weight ratio of 1: 0.03-0.06, ultrasonically stirring uniformly, then adding boric acid, mechanically stirring for 0.5-1 h, then adding sea squirt cellulose, heating to 50-70 ℃, and reacting for 0.5-3 h to obtain a solution;
s3: extracting the solution by using an injector in an electrostatic spinning device, wherein the injection distance is 16cm, starting an injection pump, the spinning voltage is 26kV, and the injection speed is 0.65mL/h to obtain a fiber membrane, putting the fiber membrane into an oven, and vacuumizing and drying at 90 ℃ for 1.5h to obtain the polyimide fiber membrane of the composite ecteinascidin cellulose;
s4: putting the polyimide fiber membrane of the composite ecthyma cellulose obtained in the step S3 into a Wally beating machine for beating, wherein the beating concentration is controlled to be 0.6-1.2%, the beating time is 4-6 h, and the beating pressure is 8-11 kg;
s5: putting the beaten polyimide fiber of the composite sea squirt cellulose in the step S4 into a defiberizing machine, adding a dispersant, a reinforcing agent and an adhesive, and then making paper by a wet papermaking process, wherein the quantitative amount is 30g/m2And obtaining the polyimide substrate-supported battery diaphragm paper.
2. The method for preparing a battery separator with high stability and long cycle life according to claim 1, wherein in step S2, the particle size of the polyimide resin powder is 30-50 μm.
3. The method as claimed in claim 1, wherein the boric acid is added in an amount of about 0.2 to 0.3 times and the sea squirt cellulose is added in an amount of about 0.06 to 0.1 times the mass of the polyamic acid solution in step S2.
4. The method for preparing the battery separator with high stability and long cycle life according to claim 1, wherein in the step S5, the weight ratio of the polyimide fibers, the dispersing agent, the reinforcing agent and the adhesive of the sea squirt cellulose is 30-50: 1:1.1: 0.7.
5. The method of claim 1, wherein in step S5, the dispersant, the reinforcing agent and the adhesive are toluene diisocyanate, DH-4 reinforcing agent and dimethylolpropionic acid.
6. The method for preparing the battery diaphragm with high stability and long cycle life according to claim 1, wherein a Bulboli beater is used for beating, the beating concentration is controlled to be 0.6-1.1%, the beating time is 4-5.5 h, and the beating pressure is 8-11 kg.
CN202111263872.3A 2021-10-27 2021-10-27 Preparation method of battery diaphragm with high stability and long cycle life Pending CN113991246A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115058920A (en) * 2022-06-06 2022-09-16 南京奥鑫新材料科技有限公司 Preparation method of diaphragm paper in technical field of batteries
CN115411451A (en) * 2022-08-26 2022-11-29 深圳市朗泰沣电子有限公司 Impact-resistant lithium battery composite film and preparation method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115058920A (en) * 2022-06-06 2022-09-16 南京奥鑫新材料科技有限公司 Preparation method of diaphragm paper in technical field of batteries
CN115411451A (en) * 2022-08-26 2022-11-29 深圳市朗泰沣电子有限公司 Impact-resistant lithium battery composite film and preparation method thereof
CN115411451B (en) * 2022-08-26 2024-03-08 深圳市朗泰沣电子有限公司 Impact-resistant lithium battery composite film and preparation method thereof

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