CN117748050A - Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm - Google Patents
Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm Download PDFInfo
- Publication number
- CN117748050A CN117748050A CN202311750178.3A CN202311750178A CN117748050A CN 117748050 A CN117748050 A CN 117748050A CN 202311750178 A CN202311750178 A CN 202311750178A CN 117748050 A CN117748050 A CN 117748050A
- Authority
- CN
- China
- Prior art keywords
- polyvinylidene fluoride
- nitrile
- polyether ketone
- diaphragm
- hours
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002033 PVDF binder Substances 0.000 title claims abstract description 80
- 229920002981 polyvinylidene fluoride Polymers 0.000 title claims abstract description 80
- 229920001643 poly(ether ketone) Polymers 0.000 title claims abstract description 73
- 150000002825 nitriles Chemical class 0.000 title claims abstract description 67
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 title claims abstract description 25
- 238000002360 preparation method Methods 0.000 title claims abstract description 12
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 238000005191 phase separation Methods 0.000 claims abstract description 8
- 239000002904 solvent Substances 0.000 claims abstract description 8
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 72
- 239000000843 powder Substances 0.000 claims description 41
- 239000000243 solution Substances 0.000 claims description 41
- 238000010438 heat treatment Methods 0.000 claims description 34
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 33
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 30
- 238000002156 mixing Methods 0.000 claims description 20
- 238000003756 stirring Methods 0.000 claims description 20
- 239000008367 deionised water Substances 0.000 claims description 18
- 229910021641 deionized water Inorganic materials 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 16
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 16
- 239000011259 mixed solution Substances 0.000 claims description 13
- 239000007787 solid Substances 0.000 claims description 13
- 238000011282 treatment Methods 0.000 claims description 11
- 230000001112 coagulating effect Effects 0.000 claims description 10
- YOYAIZYFCNQIRF-UHFFFAOYSA-N 2,6-dichlorobenzonitrile Chemical compound ClC1=CC=CC(Cl)=C1C#N YOYAIZYFCNQIRF-UHFFFAOYSA-N 0.000 claims description 8
- -1 4' -biphenol Chemical compound 0.000 claims description 8
- LSQARZALBDFYQZ-UHFFFAOYSA-N 4,4'-difluorobenzophenone Chemical compound C1=CC(F)=CC=C1C(=O)C1=CC=C(F)C=C1 LSQARZALBDFYQZ-UHFFFAOYSA-N 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- 239000012046 mixed solvent Substances 0.000 claims description 8
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 8
- 238000010992 reflux Methods 0.000 claims description 7
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 5
- 238000005266 casting Methods 0.000 claims description 5
- 239000005357 flat glass Substances 0.000 claims description 5
- 239000011521 glass Substances 0.000 claims description 5
- VCCBEIPGXKNHFW-UHFFFAOYSA-N biphenyl-4,4'-diol Chemical compound C1=CC(O)=CC=C1C1=CC=C(O)C=C1 VCCBEIPGXKNHFW-UHFFFAOYSA-N 0.000 claims description 4
- 239000003054 catalyst Substances 0.000 claims description 4
- 238000006243 chemical reaction Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 4
- 239000000376 reactant Substances 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- 230000002194 synthesizing effect Effects 0.000 claims description 4
- 238000005406 washing Methods 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 3
- 239000003792 electrolyte Substances 0.000 abstract description 13
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 abstract description 8
- 229910001416 lithium ion Inorganic materials 0.000 abstract description 8
- 229920001577 copolymer Polymers 0.000 abstract description 4
- 239000000463 material Substances 0.000 abstract description 4
- 238000010521 absorption reaction Methods 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N ether Substances CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 abstract description 3
- 239000011244 liquid electrolyte Substances 0.000 abstract description 3
- 238000010534 nucleophilic substitution reaction Methods 0.000 abstract description 3
- 238000006068 polycondensation reaction Methods 0.000 abstract description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 abstract description 2
- 125000004093 cyano group Chemical group *C#N 0.000 abstract description 2
- 229910052760 oxygen Inorganic materials 0.000 abstract description 2
- 239000001301 oxygen Substances 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 39
- 238000002844 melting Methods 0.000 description 12
- 230000008018 melting Effects 0.000 description 12
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 11
- 229910052744 lithium Inorganic materials 0.000 description 11
- 239000012528 membrane Substances 0.000 description 8
- 239000002131 composite material Substances 0.000 description 6
- 229920000098 polyolefin Polymers 0.000 description 6
- 239000004698 Polyethylene Substances 0.000 description 4
- 229920000573 polyethylene Polymers 0.000 description 4
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000006482 condensation reaction Methods 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 238000010041 electrostatic spinning Methods 0.000 description 3
- 238000010907 mechanical stirring Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000001502 supplementing effect Effects 0.000 description 2
- 239000004721 Polyphenylene oxide Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000001523 electrospinning Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000010954 inorganic particle Substances 0.000 description 1
- 238000002536 laser-induced breakdown spectroscopy Methods 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 239000004745 nonwoven fabric Substances 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Landscapes
- Cell Separators (AREA)
Abstract
A preparation method of a high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm belongs to the technical field of lithium ion battery materials. According to the invention, the polyether ketone nitrile copolymer is synthesized through nucleophilic substitution polycondensation reaction, and is blended with polyvinylidene fluoride, and then phase separation is carried out by adopting a non-solvent to obtain the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm. In the battery diaphragm, the crystallinity of the blend film can be reduced by the polyether ketone nitrile, and the affinity of the blend film with the liquid electrolyte is enhanced by the polar carboxyl and the oxygen ether bond on the polyether ketone main chain, so that the introduction of the cyano group in the polyether ketone nitrile is beneficial to improving the absorption rate of the electrolyte, and the electrochemical window is widened, so that the diaphragm has high ionic conductivity, good electrolyte wettability and strong heat resistance.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery materials, and particularly relates to a preparation method of a high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm.
Background
With the development of high-performance lithium ion battery technology, higher requirements are put forward on the modification design of the diaphragm, and the diaphragm is used as an important safety element and plays a key role in the safety performance and electrochemical performance of the battery. The separator can not only effectively isolate the anode and the cathode so as to avoid short circuit, but also provide an unobstructed passage for lithium ions to pass through the liquid electrolyte. Acceptable separators should have adequate porosity, good electrochemical stability and thermal stability. Polyolefin separators are one of the most common commercial separator materials, such as polypropylene (PP) and Polyethylene (PE), due to their high mechanical properties, excellent electrochemical stability, low cost, etc. However, polyolefin separators have a low melting point, poor electrolyte wetting, and severe dimensional shrinkage is likely to occur at high temperatures, resulting in internal short circuits and further inducing LIBS thermal runaway.
In order to make up for the deficiency of the polyolefin membrane and meet the requirement of high-performance lithium ion batteries, researchers at home and abroad mainly adopt a method for modifying the polyolefin membrane, such as a chemical grafting method and inorganic or organic coating modification of the polyolefin membrane on the surface. However, the use of chemical grafting modification increases the subsequent processing steps and tends to cause clogging of the membrane micropores; coating inorganic nano particles on the surface of a PE membrane can improve the thermal stability of the PE membrane, but the method is easy to cause the membrane surface to be closed, and the preparation process is difficult to control accurately. Therefore, it is urgent to develop a new material to replace polyolefin separator.
The chinese patent application No. 201810504179.2 discloses a method for manufacturing a composite separator for a lithium ion power battery, in which a mixture of poly (arylene ether nitrile) and polyvinyl alcohol is made into a non-woven fabric fiber layer through an electrospinning process, and then a functional group is introduced, and an inorganic particle layer is coated on a substrate to enhance the heat resistance of the separator, but this easily causes the pores in the separator to be closed, and the manufacturing process is complicated and difficult to control. The Chinese patent with application number 202310804126.3 discloses a preparation method of a functional power battery electrostatic spinning lithium supplementing diaphragm, and an electrostatic spinning technology is adopted to combine a lithium supplementing agent and a polyvinylidene fluoride electrostatic spinning diaphragm, so that the wettability of electrolyte is increased, but the safety performance of the battery can be limited due to the influence of high crystallinity and interface resistance of polyvinylidene fluoride.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides a preparation method of a high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm. According to the invention, the polyether ketone nitrile copolymer is synthesized through nucleophilic substitution polycondensation reaction, and is blended with polyvinylidene fluoride, then a non-solvent induced phase separation method is adopted to prepare the high heat-resistant lithium battery diaphragm, and the influence of polyether ketone nitrile on the diaphragm structure and performance is researched through preparing the polyether ketone nitrile/polyvinylidene fluoride diaphragms with different compounding ratios. In addition, the change of the thermal stability and the electrolyte absorptivity of the polyether ketone nitrile/polyvinylidene fluoride composite membrane prepared by different annealing treatments is studied.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the preparation method of the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm comprises the following steps:
step 1, synthesizing polyether ketone nitrile:
1.1 adding 4,4 '-biphenol, 2, 6-dichlorobenzonitrile and 4,4' -difluorobenzophenone as reactants and potassium carbonate as a catalyst into a three-necked flask with a thermometer, a water separator, a condensation reflux device and a mechanical stirring device to obtain mixture powder; injecting toluene into a water separator; wherein, the mole ratio of 4,4 '-difluorobenzophenone, 4' -biphenol, 2, 6-dichlorobenzonitrile and potassium carbonate is 1:3: (2.1-2.4): 4.2;
1.2 adding a mixed solvent of N-methylpyrrolidone and toluene into the mixture powder obtained in the step 1.1, and stirring and uniformly mixing to obtain a mixed solution A; in the mixed solvent, the volume ratio of N-methyl pyrrolidone to toluene is 3:1; wherein, the molar ratio of toluene injected in the water separator in the step 1.1 and toluene added in the mixture powder in the step 1.2 is 1 (1.35-1.8);
1.3 heating and refluxing the mixed solution A obtained in the step 1.2 at 140 ℃ for 2-5 h, releasing toluene in a water separator, then heating to 150-159 ℃ and preserving heat for 1-2 h at 150-159 ℃, heating to 160-169 ℃ and preserving heat for 1-2 h at 160-169 ℃, heating to 170-179 ℃ and preserving heat for 1-2 h at 170-179 ℃, heating to 180-190 ℃ and preserving heat for 1-2 h at 180-190 ℃, carrying out dehydration condensation reaction, and pouring the obtained reaction solution into deionized water when the viscosity is not increased any more, and stirring to obtain strip-shaped solid;
1.4 soaking the strip-shaped solid obtained in the step 1.3 in 10wt% hydrochloric acid solution for 24 hours, crushing, and washing with deionized water for 3-5 times until the solution is neutral; placing the washed powder into a baking oven and drying at 100 ℃ for 24-48 hours to obtain polyether ketone nitrile powder;
step 2, preparing a polyether ketone nitrile/polyvinylidene fluoride blending hot solution:
2.1 adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, heating and stirring for 2-5 h at 140-150 ℃ to obtain a uniform solution B;
2.2 adding polyvinylidene fluoride and N-methyl pyrrolidone into the solution B obtained in the step 2.1, and continuously heating and stirring for 2 hours at 140-150 ℃ to obtain a polyether ketone nitrile/polyvinylidene fluoride blending hot solution; wherein, the mass ratio of the polyether ketone nitrile to the polyvinylidene fluoride is 1: (0.25-4), wherein the solid-to-liquid ratio of the mixed solid powder of the polyether ketone nitrile powder and the polyvinylidene fluoride to the N-methyl pyrrolidone is 1g: (15-35) mL;
step 3, preparing the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm by adopting a non-solvent induced phase separation method:
3.1 pouring the polyether-ketone-nitrile/polyvinylidene fluoride blending hot solution obtained in the step 2 on a clean and flat glass plate, and casting a wet film by using a four-side film coater;
3.2, directly immersing the glass plate with the wet film obtained in the step 3.1 into a coagulating bath for 10-20 min, separating to form a diaphragm with a porous structure, and immersing the diaphragm in deionized water; wherein, the coagulating bath is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1;
and 3.3, airing the diaphragm obtained after the treatment in the step 3.2 at room temperature, and obtaining the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm.
Compared with the prior art, the invention has the beneficial effects that:
according to the preparation method of the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm, the polyether ketone nitrile copolymer is synthesized through nucleophilic substitution polycondensation reaction, and after the polyether ketone nitrile copolymer is blended with polyvinylidene fluoride, the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm is obtained through non-solvent induced phase separation. In the battery diaphragm, the crystallinity of the blend film can be reduced by the polyether ketone nitrile, and the affinity of the blend film with the liquid electrolyte is enhanced by the polar carboxyl and the oxygen ether bond on the polyether ketone main chain, so that the introduction of the cyano group in the polyether ketone nitrile is beneficial to improving the absorption rate of the electrolyte, and the electrochemical window is widened, so that the diaphragm has high ionic conductivity, good electrolyte wettability and strong heat resistance.
Drawings
FIG. 1 is a synthetic route to the polyether ketone nitrile of step 1;
FIG. 2 is the electrolyte wettability of the PEN/PVDF lithium battery separator prepared in example 3 and comparative example 8;
FIG. 3 shows the heat stability of the polyether ketone nitrile/polyvinylidene fluoride lithium battery separators prepared in examples 1 to 3 and comparative examples 4 to 6 and that of comparative examples 7 and comparative example 8;
fig. 4 is a graph showing the battery cycle performance of the lithium polyetherketonenitrile/polyvinylidene fluoride battery separator prepared in example 3 and comparative example 8.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings and examples.
Example 1
The preparation method of the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm comprises the following steps:
step 1, synthesizing polyether ketone nitrile:
1.1 adding 4,4 '-biphenol, 2, 6-dichlorobenzonitrile and 4,4' -difluorobenzophenone as reactants and potassium carbonate as a catalyst into a three-necked flask with a thermometer, a water separator, a condensation reflux device and a mechanical stirring device to obtain mixture powder; injecting toluene into a water separator; wherein, the mole ratio of 4,4 '-difluorobenzophenone, 4' -biphenol, 2, 6-dichlorobenzonitrile and potassium carbonate is 1:3:2.2:4.2;
1.2 adding a mixed solvent of N-methylpyrrolidone and toluene into the mixture powder obtained in the step 1.1, and stirring and uniformly mixing to obtain a mixed solution A; in the mixed solvent, the volume ratio of N-methyl pyrrolidone to toluene is 3:1; wherein, the molar ratio of toluene injected in the water separator in the step 1.1 to toluene added in the mixture powder in the step 1.2 is 1:1.8;
1.3 heating and refluxing the mixed solution A obtained in the step 1.2 at 140 ℃ for 3 hours, releasing toluene in a 3-5 mL water separator every 8-10 min, then heating to 155 ℃ at a heating rate of 2-5 ℃/min, preserving heat at 155 ℃ for 2 hours, heating to 165 ℃ and preserving heat at 165 ℃ for 2 hours, heating to 175 ℃ and preserving heat at 175 ℃ for 2 hours, heating to 185 ℃ and preserving heat at 185 ℃ for 2 hours, carrying out dehydration condensation reaction, and pouring the obtained reaction solution into deionized water when the viscosity is not increased any more, and stirring to obtain a strip-shaped solid;
1.4 soaking the strip-shaped solid obtained in the step 1.3 in 10wt% hydrochloric acid solution for 24 hours, crushing, and washing with deionized water for 3-5 times until the solution is neutral; placing the washed powder into a baking oven and drying at 100 ℃ for 36 hours to obtain polyether ketone nitrile powder;
step 2, preparing a polyether ketone nitrile/polyvinylidene fluoride blending hot solution:
2.1 adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, heating and stirring for 5 hours at 150 ℃ to obtain a uniform solution B; wherein, 10mL of N-methylpyrrolidone is added into 1g of polyether ketone nitrile powder;
2.2 adding polyvinylidene fluoride and N-methyl pyrrolidone into the solution B obtained in the step 2.1, and continuously heating and stirring for 2 hours at 150 ℃ to obtain a polyether ketone nitrile/polyvinylidene fluoride blending hot solution; wherein, the mass ratio of the polyether ketone nitrile to the polyvinylidene fluoride is 1: (0.25-4), adding 16.25mL of N-methylpyrrolidone into 1g of mixed solid powder of polyether ketone nitrile powder and polyvinylidene fluoride;
step 3, preparing the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm by adopting a non-solvent induced phase separation method:
3.1 pouring the polyether-ketone-nitrile/polyvinylidene fluoride blending hot solution obtained in the step 2 on a clean and flat glass plate, and casting a wet film by using a four-side film coater;
3.2, directly immersing the glass plate with the wet film obtained in the step 3.1 into a coagulating bath for 15min, separating to form a diaphragm with a porous structure, and immersing the diaphragm in deionized water; wherein, the coagulating bath is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1;
and 3.3, airing the diaphragm obtained after the treatment in the step 3.2 at room temperature, and obtaining the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm.
Example 2
This embodiment differs from embodiment 1 in that:
and 2, preparing a polyether ketone nitrile/polyvinylidene fluoride blending hot solution, wherein the process of preparing the polyether ketone nitrile/polyvinylidene fluoride blending hot solution is adjusted as follows:
2.1 adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, heating and stirring for 5 hours at 150 ℃ to obtain a uniform solution B; wherein, 10mL of N-methylpyrrolidone is added into 1g of polyether ketone nitrile powder;
2.2 adding polyvinylidene fluoride and N-methyl pyrrolidone into the solution B obtained in the step 2.1, and continuously heating and stirring for 2 hours at 150 ℃ to obtain a polyether ketone nitrile/polyvinylidene fluoride blending hot solution; wherein, the mass ratio of the polyether ketone nitrile to the polyvinylidene fluoride is 1: (0.25-4), adding 20mL of N-methylpyrrolidone into 1g of mixed solid powder of polyether ketone nitrile powder and polyvinylidene fluoride; the rest of the procedure is exactly the same as in example 1.
Example 3
This embodiment differs from embodiment 1 in that:
and 2, preparing a polyether ketone nitrile/polyvinylidene fluoride blending hot solution, wherein the process of preparing the polyether ketone nitrile/polyvinylidene fluoride blending hot solution is adjusted as follows:
2.1 adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, heating and stirring for 5 hours at 150 ℃ to obtain a uniform solution B; wherein, 10mL of N-methylpyrrolidone is added into 1g of polyether ketone nitrile powder;
2.2 adding polyvinylidene fluoride and N-methyl pyrrolidone into the solution B obtained in the step 2.1, and continuously heating and stirring for 2 hours at 150 ℃ to obtain a polyether ketone nitrile/polyvinylidene fluoride blending hot solution; wherein, the mass ratio of the polyether ketone nitrile to the polyvinylidene fluoride is 1: (0.25-4), adding 35mL of N-methylpyrrolidone into 1g of mixed solid powder of polyether ketone nitrile powder and polyvinylidene fluoride; the rest of the procedure is exactly the same as in example 1.
Comparative example 1
Step 1, mixing polyvinylidene fluoride and N-methyl pyrrolidone, heating and stirring for 2 hours at 150 ℃ to obtain a polyvinylidene fluoride hot solution; wherein, 10mL of N-methyl pyrrolidone is added into 1g of polyvinylidene fluoride powder;
step 2, preparing a polyvinylidene fluoride lithium battery diaphragm by adopting a non-solvent induced phase separation method:
2.1 pouring the polyvinylidene fluoride hot solution obtained in the step 1 on a clean and flat glass plate, and casting a wet film by using a four-side film coater;
2.2, directly immersing the glass plate with the wet film obtained in the step 2.1 into a coagulating bath for 15min, separating to form a diaphragm, and then immersing the diaphragm into deionized water; wherein, the coagulating bath is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1;
and 2.3, airing the diaphragm obtained after the treatment in the step 2.2 at room temperature, and thus obtaining the polyvinylidene fluoride lithium battery diaphragm.
Comparative example 2
The difference between this comparative example and example 1 is that: in the step 3.3, the diaphragm obtained after the treatment in the step 3.2 is dried at room temperature and then is heat-treated for 5 hours at 120 ℃; the remaining steps were the same as in example 1.
Comparative example 3
The difference between this comparative example and example 2 is that: in the step 3.3, the diaphragm obtained after the treatment in the step 3.2 is dried at room temperature and then is heat-treated for 5 hours at 120 ℃; the remaining steps were the same as in example 2.
Comparative example 4
The difference between this comparative example and example 3 is that: in the step 3.3, the diaphragm obtained after the treatment in the step 3.2 is dried at room temperature and then is heat-treated for 5 hours at 120 ℃; the remaining steps were the same as in example 3.
Comparative example 5
The difference between this comparative example and example 3 is that: in the step 3.3, the diaphragm obtained after the treatment in the step 3.2 is dried at room temperature and then is heat-treated for 2 hours at 200 ℃; the remaining steps were the same as in example 3.
Comparative example 6
The present comparative example differs from comparative example 1 in that: in the step 2.3, the diaphragm obtained after the treatment in the step 2.2 is dried at room temperature and then is heat-treated for 5 hours at 120 ℃; the rest of the procedure was exactly the same as in comparative example 1.
Comparative example 7
A preparation method of a polyether ketone nitrile lithium battery diaphragm comprises the following steps:
step 1, synthesizing polyether ketone nitrile:
1.1 adding 4,4 '-biphenol, 2, 6-dichlorobenzonitrile and 4,4' -difluorobenzophenone as reactants and potassium carbonate as a catalyst into a three-necked flask with a thermometer, a water separator, a condensation reflux device and a mechanical stirring device to obtain mixture powder; injecting toluene into a water separator; wherein, the mole ratio of 4,4 '-difluorobenzophenone, 4' -biphenol, 2, 6-dichlorobenzonitrile and potassium carbonate is 1:3:2.2:4.2;
1.2 adding a mixed solvent of N-methylpyrrolidone and toluene into the mixture powder obtained in the step 1.1, and stirring and uniformly mixing to obtain a mixed solution A; in the mixed solvent, the volume ratio of N-methyl pyrrolidone to toluene is 3:1; wherein, the molar ratio of toluene injected in the water separator in the step 1.1 to toluene added in the mixture powder in the step 1.2 is 1:1.8;
1.3 heating and refluxing the mixed solution A obtained in the step 1.2 at 140 ℃ for 3 hours, releasing toluene in a 3-5 mL water separator every 8-10 min, then heating to 155 ℃ at a heating rate of 2-5 ℃/min, preserving heat at 155 ℃ for 2 hours, heating to 165 ℃ and preserving heat at 165 ℃ for 2 hours, heating to 175 ℃ and preserving heat at 175 ℃ for 2 hours, heating to 185 ℃ and preserving heat at 185 ℃ for 2 hours, carrying out dehydration condensation reaction, and pouring the obtained reaction solution into deionized water when the viscosity is not increased any more, and stirring to obtain a strip-shaped solid;
1.4 soaking the strip-shaped solid obtained in the step 1.3 in 10wt% hydrochloric acid solution for 24 hours, crushing, and washing with deionized water for 3-5 times until the solution is neutral; placing the washed powder into a baking oven and drying at 100 ℃ for 36 hours to obtain polyether ketone nitrile powder;
step 2, preparing a polyether ketone nitrile hot solution:
adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, and heating and stirring for 5 hours at 150 ℃ to obtain a polyether ketone nitrile hot solution; wherein, 10mL of N-methylpyrrolidone is added into 1g of polyether ketone nitrile powder;
step 3, preparing a polyether ketone nitrile lithium battery diaphragm by adopting a non-solvent induced phase separation method:
pouring the polyether-ketone nitrile hot solution obtained in the step 2 on a clean and flat glass plate, and casting a wet film by using a four-side film coater;
3.2, directly immersing the glass plate with the wet film obtained in the step 3.1 into a coagulating bath for 15min, separating to form a diaphragm, and then immersing the diaphragm into deionized water; wherein, the coagulating bath is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1;
and 3.3, airing the diaphragm obtained after the treatment in the step 3.2 at room temperature, and thus obtaining the polyether ketone nitrile lithium battery diaphragm.
Comparative example 8
Commercial Celgard 2400 separator is commercially available.
The lithium battery separators prepared in the above examples and comparative examples were tested for various properties, and the results are shown in tables 1 and 2.
Table 1 melting point and enthalpy of fusion of battery separator
| Sample name | Melting Point 1/. Degree.C | Melting enthalpy/(J/g) | Melting Point 2/. Degree.C | Melting enthalpy 2/(J/g) | Melting Point 3/. Degree.C | Melting enthalpy 3/(J/g) |
| Example 1 | 164.7 | 43.80 | 305.3 | 0.04 | ||
| Example 2 | 163.8 | 24.30 | 307.7 | 0.25 | ||
| Example 3 | 162.9 | 7.07 | 300.4 | 1.47 | ||
| Comparative example 1 | 163.9 | 58.12 | - | - | ||
| Comparative example 2 | 165.1 | 33.45 | 306.3 | 0.18 | ||
| Comparative example 3 | 163.5 | 29.15 | 307.0 | 0.47 | ||
| Comparative example 4 | 163.0 | 6.40 | 301.8 | 1.40 | ||
| Comparative example 5 | 170.0 | 2.70 | 179 | 0.83 | 301.3 | 1.51 |
| Comparative example 6 | 165.2 | 55.39 | ||||
| Comparative example 7 | 170.2 | 87.17 | ||||
| Comparative example 8 | 311.7 | 0.25 |
Table 2 battery separator performance
As can be seen from table 1, as the proportion of polyvinylidene fluoride increases, the melting enthalpy increases, indicating that polyvinylidene fluoride can promote the crystallization of the composite separator. And the crystallinity of the composite film is smaller than that of polyvinylidene fluoride, because amorphous regions of polyvinylidene fluoride are increased, and lower crystallinity can improve conductivity. After the partial composite diaphragm is treated at 120 ℃, the melting point of polyvinylidene fluoride is hardly affected, but the crystallinity is reduced. In order to confirm the crystallinity of the composite separator, after treating example 3 in a high temperature oven at 200 ℃ for 2 hours, it was observed that the melting point of polyvinylidene fluoride in example 3 was changed to 166.9 ℃ and 179 ℃ respectively, and the melting point of the polyvinylidene fluoride component was increased by 10%, due to the increase in the α -phase content in the polyvinylidene fluoride. Table 2 shows that the polyether ketonitrile/polyvinylidene fluoride prepared in the example of the present invention has higher heat resistance than that of comparative example 7The fluorine ethylene lithium battery diaphragm has good heat resistance, high porosity of 55.54-89.86%, high electrolyte liquid absorption rate of 210-435% and 0.301-0.600 x 10 -3 S/cm ionic conductivity.
FIG. 2 is the electrolyte wettability of the PEN/PVDF lithium battery separator prepared in example 3 and comparative example 8; as can be seen from fig. 2, the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery separator prepared by the embodiment of the invention shows good electrolyte wettability, and the electrolyte can be well spread on the film. Compared with comparative example 7 and comparative example 8, the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery separator prepared by the invention has higher electrolyte wettability.
FIG. 3 shows the heat stability of the polyether ketone nitrile/polyvinylidene fluoride lithium battery separators prepared in examples 1 to 3 and comparative examples 4 to 6 and that of comparative examples 7 and comparative example 8; as can be seen from FIG. 3, compared with comparative examples 7 and 8, the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery separator prepared by the invention has good flame retardance and heat resistance, and can meet the lithium ion safety standard.
FIG. 4 is a graph showing the cycling performance of the PEN/PVDF lithium battery separator prepared in example 3 and that of comparative example 8; as can be seen from FIG. 4, compared with comparative example 8, the specific capacity of the battery assembled by the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery separator prepared by the embodiment of the invention is relatively high, reaching about 160mAh g -1 Initial discharge specific capacity 169.1mAh g at 0.5C current density -1 . After 45 cycles, the capacity retention rate of the battery is 86.64 percent, and the specific discharge capacity of the battery is 146.5mAh g -1 . The high-temperature-resistant polyether-ketone-nitrile/polyvinylidene fluoride film is used as a lithium ion battery diaphragm, and the battery performance is obviously superior to that of a Celgard 2400 diaphragm.
Claims (1)
1. The preparation method of the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm is characterized by comprising the following steps of:
step 1, synthesizing polyether ketone nitrile:
1.1 adding 4,4 '-biphenol, 2, 6-dichlorobenzonitrile and 4,4' -difluorobenzophenone as reactants and adding potassium carbonate as a catalyst into a three-necked bottle to obtain mixture powder; injecting toluene into a water separator; wherein, the mole ratio of 4,4 '-difluorobenzophenone, 4' -biphenol, 2, 6-dichlorobenzonitrile and potassium carbonate is 1:3: (2.1-2.4): 4.2;
1.2 adding a mixed solvent of N-methylpyrrolidone and toluene into the mixture powder obtained in the step 1.1, and stirring and uniformly mixing to obtain a mixed solution A; in the mixed solvent, the volume ratio of N-methyl pyrrolidone to toluene is 3:1; wherein, the molar ratio of toluene injected in the water separator in the step 1.1 and toluene added in the mixture powder in the step 1.2 is 1 (1.35-1.8);
1.3 heating and refluxing the mixed solution A obtained in the step 1.2 at 140 ℃ for 2-5 hours, releasing toluene in a water separator, then heating to 150-159 ℃ and preserving heat for 1-2 hours at 150-159 ℃, heating to 160-169 ℃ and preserving heat for 1-2 hours at 160-169 ℃, heating to 170-179 ℃ and preserving heat for 1-2 hours at 170-179 ℃, heating to 180-190 ℃ and preserving heat for 1-2 hours at 180-190 ℃, pouring the obtained reaction solution into deionized water, and stirring to obtain strip-shaped solid;
1.4 soaking the strip-shaped solid obtained in the step 1.3 in hydrochloric acid solution for 24 hours, crushing, and washing with deionized water to neutrality; drying the washed powder in a baking oven to obtain polyether ketone nitrile powder;
step 2, preparing a polyether ketone nitrile/polyvinylidene fluoride blending hot solution:
2.1 adding N-methyl pyrrolidone and the polyether ketone nitrile powder obtained in the step 1 into a three-necked bottle, heating and stirring for 2-5 h at 140-150 ℃ to obtain a uniform solution B;
2.2 adding polyvinylidene fluoride and N-methyl pyrrolidone into the solution B obtained in the step 2.1, and continuously heating and stirring for 2 hours at 140-150 ℃ to obtain a polyether ketone nitrile/polyvinylidene fluoride blending hot solution; wherein, the mass ratio of the polyether ketone nitrile to the polyvinylidene fluoride is 1: (0.25-4), wherein the solid-to-liquid ratio of the mixed solid powder of the polyether ketone nitrile powder and the polyvinylidene fluoride to the N-methyl pyrrolidone is 1g: (15-35) mL;
step 3, preparing the high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm by adopting a non-solvent induced phase separation method:
3.1 pouring the polyether-ketone-nitrile/polyvinylidene fluoride blending hot solution obtained in the step 2 on a clean and flat glass plate, and casting a wet film by using a four-side film coater;
3.2 immersing the glass plate with the wet film obtained in the step 3.1 into a coagulating bath for 10-20 min, separating to form a diaphragm with a porous structure, and immersing the diaphragm into deionized water; wherein, the coagulating bath is a mixed solution of anhydrous ethanol and deionized water in a volume ratio of 1:1;
and 3.3, airing the diaphragm obtained after the treatment in the step 3.2 at room temperature, and obtaining the high heat-resistant polyether-ketone-nitrile/polyvinylidene fluoride lithium battery diaphragm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311750178.3A CN117748050A (en) | 2023-12-19 | 2023-12-19 | Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311750178.3A CN117748050A (en) | 2023-12-19 | 2023-12-19 | Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117748050A true CN117748050A (en) | 2024-03-22 |
Family
ID=90278840
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311750178.3A Pending CN117748050A (en) | 2023-12-19 | 2023-12-19 | Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117748050A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118448811A (en) * | 2024-07-08 | 2024-08-06 | 湖南博盛新能源技术有限公司 | Heat-resistant lithium ion battery diaphragm and preparation method thereof |
-
2023
- 2023-12-19 CN CN202311750178.3A patent/CN117748050A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118448811A (en) * | 2024-07-08 | 2024-08-06 | 湖南博盛新能源技术有限公司 | Heat-resistant lithium ion battery diaphragm and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108346765B (en) | Composite lithium ion battery diaphragm and preparation method thereof | |
| Kang et al. | A thermostability gel polymer electrolyte with electrospun nanofiber separator of organic F-doped poly-m-phenyleneisophthalamide for lithium-ion battery | |
| JP5524330B2 (en) | Polymer composite electrolyte, battery containing polymer composite electrolyte, and method for preparing the same | |
| CN103087337B (en) | A kind of poly-pyrrole throat/sulfonated polymer composite proton exchange membrane material and preparation method thereof and application | |
| CN117748050A (en) | Preparation method of high heat-resistant polyether ketone nitrile/polyvinylidene fluoride lithium battery diaphragm | |
| CN101003637B (en) | Polymer electrolyte membrane, method of preparing the same and fuel cell employing the same | |
| CN107240663B (en) | Polymer coating diaphragm and preparation method thereof | |
| KR20110021217A (en) | Polymer electrolyte membrane for fuel cell and method of manufacturing the same | |
| JP2013503436A (en) | POLYMER ELECTROLYTE MEMBRANE FOR FUEL CELL AND METHOD FOR PRODUCING THE SAME | |
| CN106025149A (en) | High-temperature-resistant composite lithium battery diaphragm and preparation method for same | |
| KR20110006122A (en) | Polymer electrolyte membrane for fuel cell and method of manufacturing the same | |
| CN103718360A (en) | Polymer electrolyte membrane for fuel cell and method for manufacturing the same | |
| JP5791732B2 (en) | POLYMER ELECTROLYTE AND METHOD FOR PRODUCING THE SAME | |
| CN108774808B (en) | Polyimide nanofiber membrane with cross-linked appearance and zirconium dioxide coated surface and preparation method thereof | |
| CN108285643A (en) | Cellulose nano-fibrous/the Sulfonated Polyethersulfone Proton Exchange Membrane of one kind and preparation method | |
| Yang et al. | Two step modification of poly (vinyl alcohol) by UV radiation with 2-hydroxy ethyl methacrylate and sol–gel process for the application of polymer electrolyte membrane | |
| CN111477816A (en) | Lithium ion battery diaphragm and preparation method thereof | |
| CN110957452A (en) | Preparation method of coating diaphragm containing PMMA and PEEK | |
| CN104689726A (en) | Method for preparing hydrophilic modified polypropylene hollow fiber membrane | |
| CN110105575A (en) | A kind of low-k poly (arylene ether nitrile) and preparation method thereof | |
| CN104743543B (en) | A kind of preparation method of polyaniline/phenolic aldehyde base material with carbon element | |
| CN101481457B (en) | Crosslinked polybenzimidazoles thin film containing sulfonic group and preparation thereof | |
| CN112952295B (en) | Polyolefin-cellulose composite diaphragm and preparation method thereof | |
| CN107903416A (en) | Amphoteric ion exchange membrane of poly(aryl ether ketone) containing naphthyridine ketone structure and preparation method thereof | |
| KR20130004615A (en) | Composite electrolyte membrane for fuel cell and method for manufacturing the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |