阅读说明：本技术 一种具有良好稳定性的锂硫电池隔膜的制备方法 (Preparation method of lithium-sulfur battery diaphragm with good stability ) 是由 宋强 于 2021-01-08 设计创作，主要内容包括：本发明公开了一种具有良好稳定性的锂硫电池隔膜的制备方法,包括以下步骤：首先以对苯二胺和对苯二甲酰氯为原料,过硫酸铵和吡啶为引导剂,聚合生成聚对苯二甲酰对苯二胺,将乙炔黑和吡咯搅拌后,之后利用鸡蛋壳为模板,煅烧生成多孔碳材料,之后混合搅拌涂延在玻璃板上,干燥后得到隔膜。所述方法制备的隔膜具有良好的机械强度,鸡蛋壳和乙炔黑的负载提升了隔膜的机械强度和充放电循环性能,所用原料来源广泛,制备方法简单,适合大规模生产。(The invention discloses a preparation method of a lithium-sulfur battery diaphragm with good stability, which comprises the following steps: firstly, taking p-phenylenediamine and paraphthaloyl chloride as raw materials, taking ammonium persulfate and pyridine as guiding agents, polymerizing to generate poly-p-phenylene terephthalamide, stirring acetylene black and pyrrole, then calcining to generate a porous carbon material by taking an egg shell as a template, then mixing, stirring, coating on a glass plate, and drying to obtain the diaphragm. The diaphragm prepared by the method has good mechanical strength, the mechanical strength and the charge-discharge cycle performance of the diaphragm are improved by the loading of the eggshell and the acetylene black, the sources of the used raw materials are wide, the preparation method is simple, and the diaphragm is suitable for large-scale production.)

1. A preparation method of a lithium-sulfur battery separator with good stability is characterized by comprising the following steps:

s1: adding p-phenylenediamine into N-methylpyrrolidone, stirring for 1-2h at the temperature of 60-80 ℃, adding terephthaloyl chloride, cooling to-10 to-5 ℃, then adding pyridine and ammonium persulfate under vigorous stirring, and continuing to stir for 4-6 h;

s2: weighing acetylene black, dispersing in deionized water containing 1-2 wt% of hexadecyl trimethyl ammonium bromide, performing ultrasonic treatment on the mixture at room temperature for 1h, adding pyrrole monomer into the mixed solution, and continuously stirring for 20-40 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 0-5 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting the egg shells and the modified acetylene black prepared by S2 into a mortar, mixing and grinding to 40-60 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Carrying out a calcination reaction in an atmosphere;

s5: and adding the product S4 into S1, stirring for 2-4h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 6-8h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

2. The method for preparing the lithium-sulfur battery separator with good stability according to claim 1, wherein in the step S1, the mass-to-volume ratio of p-phenylenediamine, N-methylpyrrolidone, terephthaloyl chloride, pyridine and ammonium persulfate is 1 g: (10-15) ml: (1-2) g: (0.5-1) g: (0.5-1) g.

3. The method for preparing a lithium-sulfur battery separator having good stability according to claim 1, wherein in step S2, the mass-to-volume ratio of acetylene black, pyrrole and deionized water containing cetyltrimethylammonium bromide is 1 g: (0.2-0.4) g: (10-20) ml.

4. The method of claim 1, wherein in the step S3, the mass ratio of the eggshell to the modified acetylene black is 1: 1.

5. The method of claim 1, wherein in the step S3, the calcination temperature is 800-1000 ℃ and the calcination time is 2-4 h.

6. The method for preparing a lithium-sulfur battery separator having good stability according to any one of claims 1 to 5, wherein the separator prepared by the method is used for a lithium-sulfur battery separator.

Technical Field

The invention relates to the field of diaphragms, in particular to a preparation method of a lithium-sulfur battery diaphragm with good stability.

Background

Rechargeable battery energy is considered as an effective strategy for energy crisis problem, and has become a hot spot for scientific research and practical application. Lithium ion batteries are widely popularized and applied by virtue of their superior performance. However, the theoretical energy density of the lithium ion battery is limited, and the positive electrode material of the lithium ion battery is composed of heavy metal compounds, so that the lithium ion battery is easy to pollute the environment. Meanwhile, the price of the anode material is expensive and the resources are in short supply, so that the market requirements cannot be well met. Therefore, there is a need to develop a battery system with high energy density. Lithium Sulfur Batteries (LSBs) are being investigated as a new battery energy sourceThe attention of the personnel is focused. The high energy density characteristic (the mass specific energy and the theoretical specific capacity can reach 2600W h kg respectively)^-1And 1675mAh g^-1) Endows the product with great application prospect. In addition, elemental sulfur has the advantages of abundant resources, low price and environmental friendliness. At present, LSBs have become a research hotspot for pursuing in the energy storage field of various countries in the world.

In the preparation of the lithium-sulfur battery, the diaphragm is an important component, the diaphragm used at present is mostly a polyolefin diaphragm mainly comprising commercial polypropylene (PP), and the commercial PP diaphragm is widely applied to the lithium ion battery and is beneficial to the migration of lithium ions. However, the separator is not high in mechanical strength, easy to damage, low in stability and capable of melting at high temperature, so that the purpose of improving the performance of the separator needs to be achieved through modifying the separator, the modification of the separator is mainly to coat a corresponding carbon material or metal oxide or sulfide on the separator, physical barrier to polysulfide is enhanced in the charging and discharging processes of the battery, migration to a negative electrode is prevented through physical and chemical adsorption, generation of lithium dendrite is inhibited, and the electrochemical stability of the battery is improved.

Disclosure of Invention

The invention discloses a preparation method of a lithium-sulfur battery diaphragm with good stability, which comprises the following steps:

s1: adding p-phenylenediamine into N-methylpyrrolidone, stirring for 1-2h at the temperature of 60-80 ℃, adding terephthaloyl chloride, cooling to-10 to-5 ℃, then adding pyridine and ammonium persulfate under vigorous stirring, and continuing to stir for 4-6 h;

s2: weighing acetylene black, dispersing in deionized water containing 1-2 wt% of hexadecyl trimethyl ammonium bromide, performing ultrasonic treatment on the mixture at room temperature for 1h, adding pyrrole monomer into the mixed solution, and continuously stirring for 20-40 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 0-5 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting the egg shells and the modified acetylene black prepared by S2 into a mortar, mixing and grinding to 40-60 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Carrying out a calcination reaction in an atmosphere;

s5: and adding the product S4 into S1, stirring for 2-4h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 6-8h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Preferably, in the step S1, the mass-to-volume ratio of p-phenylenediamine, N-methylpyrrolidone, terephthaloyl chloride, pyridine and ammonium persulfate is 1 g: (10-15) ml: (1-2) g: (0.5-1) g: (0.5-1) g.

Preferably, in step S2, the mass-to-volume ratio of acetylene black, pyrrole and deionized water containing cetyltrimethylammonium bromide is 1 g: (0.2-0.4) g: (10-20) ml.

Preferably, in the step S3, the mass ratio of the eggshell to the modified acetylene black is 1: 1.

Preferably, in the step S4, the calcination temperature is 800-1000 ℃, and the calcination time is 2-4 h.

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

(1) the method is characterized in that paraphthaloyl chloride and paraphenylenediamine are subjected to condensation reaction at low temperature to generate the paraphenylenediamine terephthalamide, ammonium persulfate is used as a guiding agent, and meanwhile, the ammonium persulfate can also be used as a sulfur source and is doped with an S element.

(2) The eggshell component is calcium carbonate, has very strong hardness, and the mechanical strength of diaphragm can be improved when being loaded on the film, and simultaneously, the eggshell has porous structure, uses the eggshell as the template, can obtain porous carbon material after grinding and calcining it with acetylene black, promotes the catalytic activity of diaphragm.

(3) The polypyrrole is coated on the surface of the acetylene black, so that the electric conductivity of the material is improved, and the porous material obtained by using the eggshell as a template has a porous structure and excellent electric conductivity, so that the performance of the battery is improved.

(4) The invention has wide raw material source and simple preparation method, and is suitable for large-scale production.

Detailed Description

Example 1:

a lithium-sulfur battery separator with good stability is prepared by the following steps:

s1: adding 2g of p-phenylenediamine into 25ml of N-methylpyrrolidone, stirring for 1.5h at 70 ℃, adding 3g of terephthaloyl chloride, cooling to-8 ℃, then adding 1.5g of pyridine and 1.5g of ammonium persulfate under vigorous stirring, and continuing stirring for 5 h;

s2: 1g of acetylene black is weighed and dispersed in 15ml of deionized water containing 1.5 wt% of hexadecyl trimethyl ammonium bromide, the mixture is subjected to ultrasonic treatment at room temperature for 1 hour, 0.3g of pyrrole monomer is added into the mixed solution, and the mixture is continuously stirred for 30 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 3 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting 1g of egg shell and acetylene black prepared from 1g S2 into a mortar, mixing and grinding to 50 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Calcining for 3 hours at 900 ℃ in the atmosphere;

s5: and adding the product S4 into S1, stirring for 3h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 7h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Example 2:

a lithium-sulfur battery separator with good stability is prepared by the following steps:

s1: adding 2g of p-phenylenediamine into 20ml of N-methylpyrrolidone, stirring for 1h at the temperature of 60 ℃, adding 2g of terephthaloyl chloride, cooling to the temperature of-10 ℃, then adding 1g of pyridine and 1g of ammonium persulfate under vigorous stirring, and continuing stirring for 4 h;

s2: 1g of acetylene black is weighed and dispersed in 10ml of deionized water containing 1 wt% of hexadecyl trimethyl ammonium bromide, the mixture is subjected to ultrasonic treatment at room temperature for 1 hour, 0.2g of pyrrole monomer is added into the mixed solution, and the mixture is continuously stirred for 20 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 0 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting 1g of egg shell and acetylene black prepared from 1g S2 into a mortar, mixing and grinding to 40 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Calcining for 4 hours at 800 ℃ in the atmosphere;

s5: and adding the product S4 into S1, stirring for 2h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 6h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Example 3:

a lithium-sulfur battery separator with good stability is prepared by the following steps:

s1: adding 2g of p-phenylenediamine into 30ml of N-methylpyrrolidone, stirring for 2h at 80 ℃, adding 4g of phthaloyl chloride, cooling to-5 ℃, then adding 2g of pyridine and 2g of ammonium persulfate under vigorous stirring, and continuing stirring for 6 h;

s2: 1g of acetylene black is weighed and dispersed in 20ml of deionized water containing 2 wt% of hexadecyl trimethyl ammonium bromide, the mixture is subjected to ultrasonic treatment at room temperature for 1 hour, 0.4g of pyrrole monomer is added into the mixed solution, and the mixture is continuously stirred for 40 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 5 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting 1g of egg shell and acetylene black prepared from 1g S2 into a mortar, mixing and grinding to 60 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Calcining and reacting for 2 hours at 1000 ℃ in the atmosphere;

s5: and adding the product S4 into S1, stirring for 4h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 8h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Example 4:

a lithium-sulfur battery separator with good stability is prepared by the following steps:

s1: adding 2g of p-phenylenediamine into 20ml of N-methylpyrrolidone, stirring for 1.5h at 70 ℃, adding 3g of terephthaloyl chloride, cooling to-8 ℃, then adding 1.2g of pyridine and 1.7g of ammonium persulfate under vigorous stirring, and continuing to stir for 5 h;

s2: 1g of acetylene black is weighed and dispersed in 15ml of deionized water containing 1-2 wt% of hexadecyl trimethyl ammonium bromide, the mixture is subjected to ultrasonic treatment at room temperature for 1 hour, 0.3g of pyrrole monomer is added into the mixed solution, and the mixture is continuously stirred for 30 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 3 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: putting 1g of egg shell and acetylene black prepared from 1g S2 into a mortar, mixing and grinding to 50 meshes;

s4: the mixed powder ground by S3 is put into a tube furnace and put into N₂Calcining for 3 hours at 850 ℃ under the atmosphere;

s5: and adding the product S4 into S1, stirring for 3h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 6h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Comparative example 1:

the preparation method of the lithium-sulfur battery diaphragm without the egg shell comprises the following steps:

s1: adding 2g of p-phenylenediamine into 20ml of N-methylpyrrolidone, stirring for 1.5h at 70 ℃, adding 3g of terephthaloyl chloride, cooling to-8 ℃, then adding 1.2g of pyridine and 1.7g of ammonium persulfate under vigorous stirring, and continuing to stir for 5 h;

s2: 1g of acetylene black is weighed and dispersed in 15ml of deionized water containing 1.5 wt% of hexadecyl trimethyl ammonium bromide, the mixture is subjected to ultrasonic treatment at room temperature for 1 hour, 0.3g of pyrrole monomer is added into the mixed solution, and the mixture is continuously stirred for 30 min. After the pyrrole is uniformly dispersed, stirring for 12 hours at 3 ℃ under the atmosphere of argon, then carrying out suction filtration, fully washing the pyrrole with deionized water and ethanol, and then carrying out vacuum drying at 60 ℃;

s3: and (3) putting the acetylene black prepared by the step S2 into the S1 mixed slurry, stirring for 3h, uniformly coating the acetylene black on a clean and flat glass plate, then transferring the glass plate into a drying box, drying for 6h at the temperature of 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

Comparative example 2

The preparation method of the lithium-sulfur battery diaphragm without acetylene black comprises the following steps:

s1: adding 2g of p-phenylenediamine into 20ml of N-methylpyrrolidone, stirring for 1.5h at 70 ℃, adding 3g of terephthaloyl chloride, cooling to-8 ℃, then adding 1.2g of pyridine and 1.7g of ammonium persulfate under vigorous stirring, and continuing to stir for 5 h;

s2: putting 1g of egg shells into a mortar, mixing and grinding to 50 meshes;

s3: and adding the product S2 into S1, stirring for 3h to uniformly disperse the product S1, uniformly coating the mixed slurry on a clean and flat glass plate, transferring the glass plate into a drying oven, drying for 6h at 60 ℃, and cooling to room temperature to obtain the lithium-sulfur ion battery diaphragm.

And (3) performance testing:

the tensile strength and the puncture strength of the separator obtained in examples 1 to 4 and the separator obtained in comparative examples 1 to 2 were measured.

Testing method of puncture strength of the diaphragm: the puncture strength of the membrane was measured using a puncture instrument, specifically using a 1mm diameter needle with no sharp edge at the tip, piercing the membrane vertically at a speed of 2m/min, and recording the data using a FGN-5B data recorder, with the experimental results as shown in table 1.

Tensile strength was tested according to the national standard GB/T1040.3-2008 for examples 1-4 and comparative examples 1-2, with properties given in Table 1.

Table 1: mechanical strength data of the separators prepared in examples 1 to 4 and comparative examples 1 to 2

As shown in table 1, the tensile strength and membrane puncture strength of the membranes prepared in examples 1-4 and comparative example 2 were much higher than the membrane prepared in comparative example 1, indicating that the loading of the eggshells enhanced the mechanical properties of the membrane.

Assembling a button type simulation battery in a glove box filled with argon by adopting LiCoO₂The material is a positive electrode, the lithium sheet is a negative electrode, the materials prepared in examples 1-4 and comparative examples 1-2 are separators, and electrolyte is dripped into a glove box to form the button cell. The button cell is formed in the sleeve box. The stacking sequence when assembling the battery is positive shell, shrapnel, gasket, positive plate, diaphragm, electrolyte, negative pole, gasket and negative shell. And standing the assembled button cell for 12h, and performing charge-discharge cycle test on the button cell by using a NEWARE cell test system. The discharge capacity retention rate was calculated by the following formula:

the specific discharge capacity before and after the cycle is obtained by testing the battery testing system, and the testing results are shown in table 2 and table 2: charge and discharge characteristics of separators prepared in examples 1 to 4 and comparative examples 1 to 2

As shown in Table 2, the separators of examples 1 to 4 and comparative example 1 had higher specific discharge capacities than the separator of comparative example 2, wherein the specific discharge capacity before cycling of the separator of example 1 was 1543.2mAh g^-1The specific discharge capacity after 1000 cycles is 1396.6mAh g^-1The capacity preservation rate reaches 90.6%, the capacity retention rates of the diaphragms prepared in examples 2 to 4 are all higher than 85% after 1000 cycles, and the specific discharge capacity of the diaphragm prepared in comparative example 1 is 1367 mAh.g^-1The capacity retention rate was 79.2% after 1000 cycles, while the specific discharge capacity of the separator circulation ring prepared in comparative example 2 was 853.8mAh g^-1438.85mAh g after 1000 cycles^-1The capacity retention rate is 51.4 percent, and the loading of polypyrrole-coated porous acetylene black is proved to be improvedThe charge and discharge cycle performance of the separator when used as a battery is improved.