阅读说明：本技术 耐高温聚芳醚腈锂离子电池隔膜材料及其制备方法和应用 (High-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material and preparation method and application thereof ) 是由 黄宇敏 林果 曹桐 刘孝波 于 2021-01-27 设计创作，主要内容包括：本发明公开了一种耐高温聚芳醚腈锂离子电池隔膜材料及其制备方法和应用,属于锂离子电池材料技术领域。本发明为开发一种具有高亲水性和高耐热安全性的锂离子电池隔膜,首先以2,6-二卤苯甲腈、二元酚为原料制备得到了耐高温聚芳醚腈材料；然后利用相转换法将聚芳醚腈制备为聚芳醚腈锂离子电池隔膜。本发明隔膜具有尺寸可调节的多孔结构,耐高温性能好,孔隙率和电解液吸液率高,离子电导率高的特点,其作为锂离子电池隔膜,制备的电池安全性高,循环性能突出。(The invention discloses a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, and a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The invention is to develop a lithium ion battery diaphragm with high hydrophilicity and high heat-resistant safety, firstly, 2, 6-dihalogen benzonitrile and dihydric phenol are used as raw materials to prepare a high-temperature-resistant polyarylether nitrile material; and then preparing the poly (arylene ether nitrile) into the poly (arylene ether nitrile) lithium ion battery diaphragm by using a phase conversion method. The diaphragm has the characteristics of adjustable size, porous structure, good high-temperature resistance, high porosity, high electrolyte liquid absorption rate and high ionic conductivity, and can be used as a lithium ion battery diaphragm, and the prepared battery has high safety and outstanding cycle performance.)

1. The preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material is characterized by comprising the following steps of: the method comprises the following steps: dissolving 2, 6-dihalogenobenzonitrile, dihydric phenol and an inorganic base in an organic solvent and a dehydrating agent, heating to reflux, and then gradually heating to 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃; when the viscosity is not increased any more, pouring the system into water to separate out to obtain a crude poly (arylene ether nitrile) product, and then purifying to obtain a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material; the 2, 6-dihalo benzonitrile is 2, 6-dichlorobenzonitrile or 2, 6-difluorobenzonitrile.

2. The preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery separator material according to claim 1, which is characterized in that: at least one of the following is satisfied:

the dihydric phenol is at least one of unsubstituted or substituted biphenol, unsubstituted or substituted hydroquinone, unsubstituted or substituted bisphenol A, unsubstituted or substituted bisphenol AF, unsubstituted or substituted resorcinol or unsubstituted or substituted phenolphthalein, wherein the substituted substituent is C1-C6 alkyl, 6-10 membered aryl or 5-10 membered heteroaryl;

the inorganic base is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate or potassium bicarbonate;

the molar ratio of the 2, 6-dihalo benzonitrile, the dihydric phenol and the inorganic base is 1 +/-0.1: 1 ± 0.1: 1.2 to 2.

3. The preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery separator material according to claim 1, which is characterized in that: at least one of the following is satisfied:

the organic solvent is at least one of NMP, sulfolane or diphenyl sulfone;

the dehydrating agent is toluene or xylene;

the volume ratio of the organic solvent to the dehydrating agent is 3-10: 1.

4. the preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery separator material according to claim 1, which is characterized in that: at least one of the following is satisfied:

the refluxing time is 2-5 h;

gradually heating to each temperature section of 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃ and carrying out heat preservation reaction for 1-2 h.

5. The high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material prepared by the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material according to any one of claims 1 to 4.

6. The preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm is characterized by comprising the following steps of: the method comprises the following steps:

A. dissolving the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery separator material prepared according to any one of claims 1 to 4 in a solvent to obtain a homogeneous solution with the weight fraction of the polymer being 5 to 20%;

B. after the homogeneous solution is subjected to ultrasonic treatment, casting the solution on a substrate, and then soaking the substrate in a coagulating bath to form a porous membrane;

C. and soaking the porous membrane in water, and then carrying out vacuum drying to obtain the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm.

7. The preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery separator according to claim 6, which is characterized in that: at least one of the following is satisfied:

in the step A, the solvent is at least one of NMP, DMF or DMAc;

in the step B, the ultrasonic treatment time is 1-2 h;

in the step B, the coagulating bath is at least one of water, ethanol, methanol, glycerol, acetone, N-methylpyrrolidone/water or isopropanol, wherein the N-methylpyrrolidone/water represents a volume ratio of the N-methylpyrrolidone to the water of 20-80%: 80-20%;

in the step B, the soaking time is 1-10 min.

8. The preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery separator according to claim 6, which is characterized in that: at least one of the following is satisfied:

in the step C, the soaking time is 12-48 h; the temperature of the vacuum drying is 30-80 ℃, and the time is 12-48 h;

in the step C, the aperture of the diaphragm is 40 nm-7 μm, and the hole wall of the hole has a three-dimensional through network structure;

in the step C, the thickness of the obtained diaphragm is 10-80 μm.

9. The high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm prepared by the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm as claimed in any one of claims 6 to 8.

10. The use of the high temperature resistant poly (arylene ether nitrile) lithium ion battery separator prepared according to any one of claims 6 to 8 in a lithium ion battery.

Technical Field

The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, and a preparation method and application thereof.

Background

Since the 21 st century, lithium ion batteries have attracted much attention, and the separator, which is an essential component in lithium ion batteries, not only affects the performance of the lithium ion batteries, but also determines the safety performance of lithium ions. When people pursue the high-capacity and rapid charge-discharge performance of the lithium ion battery, the performance of the diaphragm needs to be improved at first.

Polyolefin (polyethylene (PE) and polypropylene (PP)) and polyolefin composite (PP/PE) microporous membranes from companies represented by Celgard, Ube et al, usa, are currently recognized as the best quality commercial lithium ion separator. The preparation method of the diaphragm is that the movement capacity of the chain segment of the macromolecule chain segment is enhanced under high temperature through a single/double thermal stretching orientation process to generate high orientation and large-scale plastic deformation, so that a series of micropore structures are formed on the surface of the film. Although the polyolefin microporous membrane has low cost, good mechanical property and stable electrochemical property, the surface energy of the polyolefin microporous membrane is low, and the electrolyte is difficult to fully infiltrate the diaphragm. Therefore, the lithium ion migration is low and the ionic conductivity is poor in the charging and discharging processes, and the improvement of the overall performance of the battery is limited.

In addition, the polyolefin-based separator has a low melting temperature and poor thermal dimensional stability at high temperatures. The internal temperature sharply rises under the high-current high-rate charge and discharge condition, can make the diaphragm take place serious thermal contraction deformation like this, leads to the inside short circuit of battery, takes place serious incident.

Therefore, the development of a separator having high hydrophilicity and high heat resistance is currently urgently needed to be solved and is one of the main research directions.

Disclosure of Invention

The invention discloses a high-hydrophilicity and high-heat-resistant safety lithium ion battery diaphragm, and firstly provides a preparation method of a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, which comprises the following steps: dissolving 2, 6-dihalogenobenzonitrile, dihydric phenol and an inorganic base in an organic solvent and a dehydrating agent, heating to reflux, and then gradually heating to 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃; when the viscosity is not increased any more, pouring the system into water to separate out to obtain a crude poly (arylene ether nitrile) product, and then purifying to obtain a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material; the 2, 6-dihalo benzonitrile is 2, 6-dichlorobenzonitrile or 2, 6-difluorobenzonitrile.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the dihydric phenol is at least one of unsubstituted or substituted biphenol, unsubstituted or substituted hydroquinone, unsubstituted or substituted bisphenol A, unsubstituted or substituted bisphenol AF, unsubstituted or substituted resorcinol or unsubstituted or substituted phenolphthalein, wherein the substituted substituent is C1-C6 alkyl, 6-10 membered aryl or 5-10 membered heteroaryl.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the inorganic base is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate or potassium bicarbonate.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the molar ratio of the 2, 6-dihalogen benzonitrile, the dihydric phenol and the inorganic base is 1 +/-0.1: 1 ± 0.1: 1.2 to 2.

Preferably, in the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery separator material, the molar ratio of the 2, 6-dihalobenzonitrile, the dihydric phenol and the inorganic base is 1: 1: 1.2 to 2.

In the preparation method of the high-temperature-resistant polyarylethernitrile lithium ion battery diaphragm material, the organic solvent is at least one of NMP, sulfolane or diphenylsulfone.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the dehydrating agent is toluene or xylene.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the volume ratio of the organic solvent to the dehydrating agent is 3-10: 1.

in the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the refluxing time is 2-5 h.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material, the reaction is carried out for 1-2 hours while the temperature is gradually increased to each temperature range of 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃.

The invention also provides a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material prepared by the method.

On the basis, the invention further utilizes a phase conversion method to prepare the poly (arylene ether nitrile) into the poly (arylene ether nitrile) lithium ion battery diaphragm, and comprises the following steps:

A. dissolving the prepared high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material in a solvent to obtain a homogeneous solution with the weight fraction of the polymer being 5-20%;

B. after the homogeneous solution is subjected to ultrasonic treatment, casting the solution on a substrate, and then soaking the substrate in a coagulating bath to form a porous membrane;

C. and soaking the porous membrane in water, and then carrying out vacuum drying to obtain the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step A, the solvent is at least one of NMP, DMF or DMAc.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step B, the ultrasonic treatment time is 1-2 h.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step B, the coagulating bath is at least one of water, ethanol, methanol, glycerol, acetone, N-methyl pyrrolidone/water or isopropanol, wherein the N-methyl pyrrolidone/water represents 20-80% of the volume ratio of the N-methyl pyrrolidone to the water: 80-20%.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step B, the soaking time is 1-10 min.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step C, the soaking time is 12-48 hours; the temperature of the vacuum drying is 30-80 ℃, and the time is 12-48 h.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step C, the aperture of the diaphragm is 40 nm-7 mu m, and the hole wall of each hole has a three-dimensional through network structure.

In the preparation method of the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm, in the step C, the thickness of the obtained diaphragm is 10-80 μm.

The invention also provides the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm prepared by the method.

The high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm provided by the invention can be applied to a lithium ion battery, and the performance of the lithium ion battery is improved.

The invention has the beneficial effects that:

the method firstly synthesizes the poly-arylene ether nitrile with excellent heat resistance, chemical resistance, mechanical strength and good molding processability, the cyano group on the aromatic ring can enhance the adhesion performance of the polymer and a substrate through the polar action with other functional groups, and the polar cyano group can also increase the liquid absorption rate of the electrolyte, so the poly-arylene ether nitrile can be used as a high-temperature resistant lithium ion battery diaphragm base material; then, the poly (arylene ether nitrile) is prepared into a poly (arylene ether nitrile) lithium ion battery diaphragm by using a phase conversion method, and the poly (arylene ether nitrile) lithium ion battery diaphragm is matched with a positive electrode, a negative electrode and liquid electrolyte to obtain a high-performance lithium ion battery suitable for a wide temperature range; and a series of poly (arylene ether nitrile) lithium ion battery separators with different pore structures and physicochemical properties can be obtained by changing the coagulation bath in the phase conversion process. The phase conversion method is simple to operate, easy to realize, convenient to popularize and easy to realize corresponding industrial amplification.

Drawings

FIG. 1 is an SEM photograph of a polyarylene ether nitrile obtained in example 1 of the present invention.

FIG. 2 is an SEM photograph of a polyarylene ether nitrile obtained in example 2 of the present invention.

FIG. 3 is an SEM photograph of a polyarylene ether nitrile obtained in example 3 of the present invention.

FIG. 4 is an SEM photograph of a polyarylene ether nitrile obtained in example 4 of the present invention.

Detailed Description

Specifically, the preparation method of the high-temperature-resistant polyarylether nitrile lithium ion battery diaphragm material comprises the following steps: dissolving 2, 6-dihalogenobenzonitrile, dihydric phenol and an inorganic base in an organic solvent and a dehydrating agent, heating to reflux, and then gradually heating to 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃; when the viscosity is not increased any more, pouring the system into water to separate out to obtain a crude poly (arylene ether nitrile) product, and then purifying to obtain a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material; the 2, 6-dihalo benzonitrile is 2, 6-dichlorobenzonitrile or 2, 6-difluorobenzonitrile.

The invention takes 2, 6-dihalogen benzonitrile and dihydric phenol as raw materials to prepare polyaryl ether nitrile; it has been tested that it is difficult to obtain a polymer having a high molecular weight by mixing 2, 6-dihalobenzonitrile starting materials (in the art, intrinsic viscosity may be a side reaction molecular weight, and the higher the intrinsic viscosity, the larger the molecular weight), and further, it is also difficult to obtain a polymer having a high molecular weight by using 2, 6-dibromobenzonitrile or 2, 6-diiodobenzonitrile, so that 2, 6-dihalobenzonitrile in the present invention is 2, 6-dichlorobenzonitrile or 2, 6-difluorobenzonitrile.

The dihydric phenol is widely selected so long as it does not contain substituents that affect the polymerization reaction, such as halogen, additional hydroxyl, amino, and like reactive groups; preferably, the dihydric phenol is at least one of unsubstituted or substituted biphenol, unsubstituted or substituted hydroquinone, unsubstituted or substituted bisphenol A, unsubstituted or substituted bisphenol AF, unsubstituted or substituted resorcinol or unsubstituted or substituted phenolphthalein, wherein the substituted substituent is C1-C6 alkyl, 6-10 membered aryl or 5-10 membered heteroaryl. According to the addition type of the dihydric phenol, the poly (arylene ether nitrile) with different copolymerization types can be obtained in the invention.

In the invention, the inorganic base is at least one of potassium carbonate, sodium carbonate, potassium bicarbonate or potassium bicarbonate.

In the invention, the molar ratio of the 2, 6-dihalo benzonitrile, the dihydric phenol and the inorganic base is controlled to be 1 +/-0.1: 1 ± 0.1: 1.2-2; preferably, the molar ratio of the 2, 6-dihalobenzonitrile, the dihydric phenol and the inorganic base is 1: 1: 1.2 to 2.

In the invention, at least one of NMP, sulfolane or diphenyl sulfone is used as an organic solvent for polymerization reaction, and toluene or xylene is used as a dehydrating agent; controlling the volume ratio of the organic solvent to the dehydrating agent to be 3-10: 1, facilitating the dissolution of materials and the reflux dehydration; in addition, the ratio of the total amount of the organic solvent and the dehydrating agent to the total amount of the 2, 6-dihalobenzonitrile, the dihydric phenol and the inorganic base is 100 mL/65-100 g, at this time, the 2, 6-dihalobenzonitrile and the dihydric phenol can be completely dissolved, and the inorganic base is partially dissolved as an inorganic salt.

According to the invention, firstly refluxing is carried out for 2-5 h (according to the proportion of the organic solvent to the dehydrating agent, the refluxing and dehydrating temperature is generally 130-148 ℃), then the temperature is gradually increased from the refluxing temperature to 150-160 ℃, 160-170 ℃, 170-180 ℃ and 180-190 ℃, and the heat preservation reaction is carried out for 1-2 h in each temperature section, and the intermittent temperature rise and heat preservation is more beneficial to the polymerization reaction, so that the poly (arylene ether nitrile) with high molecular weight (high intrinsic viscosity) can be obtained more easily.

In the method, after the crude poly (arylene ether nitrile) product is obtained, diluted hydrochloric acid, acetone and water can be adopted for washing in sequence, unreacted raw materials, alkali and other impurities are cleaned, filtered and dried, and the purified poly (arylene ether nitrile) (PEN) is obtained.

The invention also provides a high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material prepared by the method.

On the basis, the invention further utilizes a phase conversion method to prepare the poly (arylene ether nitrile) into the poly (arylene ether nitrile) lithium ion battery diaphragm, and comprises the following steps:

A. dissolving the prepared high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm material in a solvent to obtain a homogeneous solution with the weight fraction of the polymer being 5-20%;

B. after the homogeneous solution is subjected to ultrasonic treatment, casting the solution on a substrate, and then soaking the substrate in a coagulating bath to form a porous membrane;

C. and soaking the porous membrane in water, and then carrying out vacuum drying to obtain the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm.

In step A of the method, the solvent is at least one of NMP, DMF or DMAc; and the concentration of the homogeneous phase solution is controlled to be 5-20%, the phenomenon that the polymer is low to cause that the film is difficult to form is avoided, and the phenomenon that the viscosity of the solution is too high to cause that the thickness of the diaphragm is too large to influence the service performance of the diaphragm (the thickness range of the diaphragm of a common lithium ion battery is 8-80 um) is also avoided.

In the step B of the method, the time of ultrasonic treatment is 1-2 h, so that bubbles can be removed as far as possible.

In step B of the method, the coagulating bath is at least one of water, ethanol, methanol, glycerol, acetone, N-methyl pyrrolidone/water or isopropanol; according to tests, the film can be dissolved and cannot be formed by singly using the N-methylpyrrolidone, so that the N-methylpyrrolidone/water represents that the volume ratio of the N-methylpyrrolidone to the water is 20-80%: 80-20%.

In the step B, firstly, soaking in a coagulating bath for 1-10 min to preliminarily form a film; then soaking the membrane in water for 12-48 h in the step C to further form the membrane, and simultaneously cleaning the membrane to remove impurities such as organic solvents; the temperature of the vacuum drying is 30-80 ℃, and the time is 12-48 h.

In the step C of the method, the aperture of the diaphragm is 40 nm-7 mu m, and the hole wall of the hole has a three-dimensional through network structure; the thickness of the obtained separator is 10-80 μm.

In the invention, in order to avoid introducing impurity ions, the adopted water does not generally use tap water, but uses distilled water, secondary distilled water, deionized water, ultrapure water and the like.

The invention also provides the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm prepared by the method.

The high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm provided by the invention can be applied to a lithium ion battery, and the performance of the lithium ion battery is improved.

The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

Example 1

Step 1 (material synthesis): 2, 6-Dichlorobenzonitrile (DCBN), dihydric phenol (hydroquinone) and potassium carbonate (K)₂CO₃) The molar ratio of the raw materials is 1: 1: 2, dissolving in NMP and toluene, starting stirring, heating to 146 ℃, and keeping for 3 hours; then gradually heating the temperature of the reaction system to 156 ℃, 166 ℃, 176 ℃ and 180 ℃ for reaction for two hours respectively; and when the viscosity is not increased any more, pouring the product into deionized water for precipitation to obtain a crude poly (arylene ether nitrile) product, then sequentially purifying with dilute hydrochloric acid, acetone and water, filtering and drying to obtain the purified poly (arylene ether nitrile) (PEN), wherein the intrinsic viscosity of the purified poly (arylene ether nitrile) (PEN) at 25 ℃ and with NMP as a solvent is 1.25, and the structural formula is as follows.

Step 2 (membrane preparation): dissolving PEN polymer in NMP solvent at room temperature under a magnetic stirrer to obtain a homogeneous solution with the polymer weight fraction of 10%; then, treating the solution for 2 hours by ultrasonic waves to remove bubbles, then casting the solution on a dry, clean and flat glass substrate by using a casting knife at room temperature, and then directly immersing the glass substrate into deionized water for 3 minutes to form a membrane with a porous structure; and then, soaking the membrane with the porous structure in deionized water for 24 hours, and performing vacuum drying at 80 ℃ for 24 hours before testing and device manufacturing to obtain the high-temperature-resistant lithium ion battery porous membrane.

The battery performance of the CR2032 battery in the voltage range of 2.4-4.2 v is researched on a battery test system. The lithium ion battery comprises a positive electrode, a negative electrode, a shell and the obtained lithium battery diaphragm, wherein the lithium battery diaphragm is filled with electrolyte. The assembly of all cells was performed in an argon filled glove box. The room temperature working electrolyte solution is 1mol/LLIPF₆(the solvent was ethyl carbonate: dimethyl carbonate ═ 1: 1 (V/V)). For the high temperature measurement, the test conditions were the same at room temperature, but a commercial liquid electrolyte (chinese fossa chemistry) was usedCompany LX-081) as the working electrolyte. The anode material of the half-cell test is lithium iron phosphate, and the cathode is a lithium sheet. The positive electrode material of the full cell is lithium iron phosphate, and the negative electrode is a graphite pole piece.

Example 2

Step 1 (material synthesis): 2, 6-Dichlorobenzonitrile (DCBN), dihydric phenol (bisphenol A) and potassium carbonate (K)₂CO₃) The molar ratio of the raw materials is 1: 1: 1.5, dissolving in NMP and toluene, starting stirring and heating to 146 ℃ for 3 h; then gradually heating the temperature of the reaction system to 156 ℃, 166 ℃, 176 ℃ and 180 ℃ for reaction for two hours respectively; when the viscosity is not increased any more, pouring the product into deionized water to separate out crude poly (arylene ether nitrile), then purifying with dilute hydrochloric acid, acetone and water in sequence, filtering and drying to obtain the purified poly (arylene ether nitrile) (PEN), wherein the intrinsic viscosity of the purified poly (arylene ether nitrile) (PEN) at 25 ℃ and with NMP as a solvent is 0.93, and the structural formula is as follows.

Step 2 (membrane preparation): dissolving PEN polymer in NMP solvent at room temperature under a magnetic stirrer to obtain a homogeneous solution with the polymer weight fraction of 10%; then, treating the solution by ultrasonic for 2 hours to remove bubbles, then casting the solution on a dry, clean and flat glass substrate by using a casting knife at room temperature, and then directly immersing the glass substrate in methanol for 5 minutes to form a membrane with a porous structure; and then, soaking the membrane with the porous structure in deionized water for 48h, and performing vacuum drying at 60 ℃ for 24h before testing and device manufacturing to obtain the high-temperature-resistant lithium ion battery porous membrane.

The battery performance of the CR2032 battery in the voltage range of 2.4-4.2 v is researched on a battery test system. The lithium ion battery comprises a positive electrode, a negative electrode, a shell and the obtained lithium battery diaphragm, wherein the lithium battery diaphragm is filled with electrolyte. The assembly of all cells was performed in an argon filled glove box. The room temperature working electrolyte solution is 1mol/LLIPF₆(ethyl carbonate: dimethyl carbonate ═ 1: 1 (V/V)). For the pyrometry, the test conditions were the same as at room temperature, but the quotient was usedLiquid electrolyte (LX-081, Fox chemical Co., China) was used as the working electrolyte. The anode material of the half-cell test is lithium iron phosphate, and the cathode is a lithium sheet. The positive electrode material of the full cell is lithium iron phosphate, and the negative electrode is a graphite pole piece.

Example 3

Step 1 (material synthesis): 2, 6-Dichlorobenzonitrile (DCBN), dihydric phenol (the molar ratio of bisphenol A to diphenol is 1: 4) and potassium carbonate (K)₂CO₃) The molar ratio of the raw materials is 1: 1: 1.5, dissolving in NMP and toluene, starting stirring and heating to 146 ℃ for 3 h; then gradually heating the temperature of the reaction system to 156 ℃, 166 ℃, 176 ℃ and 180 ℃ for reaction for two hours respectively; when the viscosity is not increased any more, pouring the product into deionized water to precipitate a crude poly (arylene ether nitrile) product, then sequentially purifying with dilute hydrochloric acid, acetone and water, filtering and drying to obtain the purified poly (arylene ether nitrile) (PEN), wherein the intrinsic viscosity of the purified poly (arylene ether nitrile) (PEN) at 25 ℃ and with NMP as a solvent is 1.1, and the structural formula is as follows.

Step 2 (membrane preparation): dissolving PEN polymer in NMP solvent at room temperature under a magnetic stirrer to obtain a homogeneous solution with the polymer weight fraction of 10%; then treating the solution by ultrasonic for 2 hours to remove air bubbles, then casting the solution on a dry, clean and flat glass substrate by a casting knife at room temperature, and then directly immersing the glass substrate in N-methylpyrrolidone/deionized water (V: 8: 2) for 10 minutes to form a film with a porous structure; and then, soaking the membrane with the porous structure in deionized water for 48h, and performing vacuum drying at 60 ℃ for 48h before testing and device manufacturing to obtain the high-temperature-resistant lithium ion battery porous membrane.

The battery performance of the CR2032 battery in the voltage range of 2.4-4.2 v is researched on a battery test system. The lithium ion battery comprises a positive electrode, a negative electrode, a shell and the obtained lithium battery diaphragm, wherein the lithium battery diaphragm is filled with electrolyte. The assembly of all cells was performed in an argon filled glove box. The room temperature working electrolyte solution is 1mol/LLIPF₆(ethyl carbonate: dimethyl carbonate ═ 1: 1 (V/V)). For the high temperature measurement, the test conditions were the same as at room temperature, but a commercial liquid electrolyte (LX-081, fosetyl chemical company, china) was used as the working electrolyte. The anode material of the half-cell test is lithium iron phosphate, and the cathode is a lithium sheet. The positive electrode material of the full cell is lithium iron phosphate, and the negative electrode is a graphite pole piece.

Example 4

Step 1 (material synthesis): mixing 2, 6-Dichlorobenzonitrile (DCBN), dihydric phenol (the molar ratio of hydroquinone to biphenol is 1: 4) and potassium carbonate (K)₂CO₃) The molar ratio of the raw materials is 1: 1: 1.5, dissolving in NMP and toluene, starting stirring and heating to 146 ℃ for 3 h; then gradually heating the temperature of the reaction system to 156 ℃, 166 ℃, 176 ℃ and 180 ℃ for reaction for two hours respectively; when the viscosity is not increased any more, pouring the product into deionized water to precipitate a crude poly (arylene ether nitrile) product, then sequentially purifying with dilute hydrochloric acid, acetone and water, filtering and drying to obtain the purified poly (arylene ether nitrile) (PEN), wherein the intrinsic viscosity of the purified poly (arylene ether nitrile) (PEN) at 25 ℃ and with NMP as a solvent is 1.1, and the structural formula is as follows.

Step 2 (membrane preparation): dissolving PEN polymer in NMP solvent at room temperature under a magnetic stirrer to obtain a homogeneous solution with the polymer weight fraction of 10%; then, treating the solution by ultrasonic for 2 hours to remove bubbles, then casting the solution on a dry, clean and flat glass substrate by using a casting knife at room temperature, and then directly immersing the glass substrate in isopropanol for 10 minutes to form a membrane with a porous structure; and then, soaking the membrane with the porous structure in deionized water for 48h, and performing vacuum drying at 60 ℃ for 48h before testing and device manufacturing to obtain the high-temperature-resistant lithium ion battery porous membrane.

The battery performance of the CR2032 battery in the voltage range of 2.4-4.2 v is researched on a battery test system. The lithium ion battery comprises a positive electrode, a negative electrode, a shell and the obtained lithium battery diaphragm, wherein the lithium battery diaphragm is filled with electrolyte. Group of all cellsThe loading was carried out in an argon-filled glove box. The room temperature working electrolyte solution is 1mol/LLIPF₆(ethyl carbonate: dimethyl carbonate ═ 1: 1 (V/V)). For the high temperature measurement, the test conditions were the same as at room temperature, but a commercial liquid electrolyte (LX-081, fosetyl chemical company, china) was used as the working electrolyte. The anode material of the half-cell test is lithium iron phosphate, and the cathode is a lithium sheet. The positive electrode material of the full cell is lithium iron phosphate, and the negative electrode is a graphite pole piece.

The commercial Celgard2500 polypropylene diaphragm on the market and the porous poly (arylene ether nitrile) diaphragm distribution in examples 1-4 were subjected to performance testing, and the test data are shown in tables 1 and 2.

TABLE 1 Battery separator Performance

TABLE 2 Battery cycling Performance

In Table 2, half cell (cathode/anode: LiFePO)₄Lithium); full cell (anode/cathode: LiFePO)₄Lithium); a is the battery capacity (mAh/g) after the battery is cycled for 100 times at the normal temperature at the multiplying power of 0.5C; b is the battery capacity (mAh/g) after 100 cycles at 60 ℃ under 0.5C multiplying power.

As can be seen from Table 1, compared with Celgard2500 diaphragm, the high-temperature-resistant poly (arylene ether nitrile) lithium ion battery diaphragm prepared by the invention has good heat-resistant stability (dimensional stability), high porosity of 73.1-81%, high-efficiency electrolyte liquid absorption rate of 370-450% and 0.35-1.47 x 10^-3Ion conductivity of S/cm.

As can be seen from table 2, the poly (arylene ether nitrile) high-temperature resistant film provided by the invention is used as a lithium ion battery diaphragm, is assembled into a half battery by matching with a positive electrode and a negative electrode, and can obtain the specific discharge capacity of 137-151 mAh/g after circulating for 100 circles at room temperature and 0.5C rate; after circulating for 100 circles under the conditions of 60 ℃ and 0.5C multiplying power, the discharge specific capacity of 119-162 mAh/g can be obtained. The poly (arylene ether nitrile) high-temperature-resistant film is used as a lithium ion battery diaphragm, is assembled into a full battery by matching with a positive electrode and a negative electrode, and can obtain the discharge specific capacity of 113-135 mAh/g after circulating for 100 circles at room temperature under the condition of 0.5C multiplying power; after 100 cycles of circulation at 60 ℃ and 0.5C multiplying power, the discharge specific capacity of 118-139 mAh/g can be obtained. The poly (arylene ether nitrile) high-temperature resistant film is used as a lithium ion battery diaphragm, and the battery performance is obviously superior to Celgard 2500.