Method for preparing polyimide porous diaphragm

A polyimide, porous diaphragm technology, applied in electrical components, non-aqueous electrolyte batteries, circuits, etc., to achieve high yield, good high temperature resistance, and good reproducibility

Inactive Publication Date: 2019-03-15
SUN YAT SEN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the preparation method of polyimide diaphragm is mainly based on electrospinning method, and there are also a few reports of non-solvent-induced phase separation method, but the pyrolysis of chemically bonded porogens to prepare polyimide lithium diaphragm for lithium-ion batteries , Lithium-sulfur battery reports are extremely rare

Method used

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  • Method for preparing polyimide porous diaphragm
  • Method for preparing polyimide porous diaphragm
  • Method for preparing polyimide porous diaphragm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Embodiment 1: the bromine group capping reaction of thermally unstable polymer polypropylene carbonate diol.

[0047] (1) Synthesis of hydroxyl-terminated PPC (PPC-2OH)

[0048] Take 85g of high molecular weight PPC in a three-neck round bottom flask, and carry out mechanical stirring at 160°C in a nitrogen atmosphere. When the temperature is stabilized at 160°C, add 15g of 1,4-butanediol (BDO) for alcoholysis. After 2 hours of reaction Stop heating, cool to room temperature, add 50mL chloroform to dissolve the product, then add 50mL deionized water to wash, and separate the liquid through a separatory funnel to remove unreacted BDO and small molecule PPC-2OH, repeat washing more than 5 times, and The purified chloroform solution of PPC-2OH was transferred to a watch glass, and the chloroform was volatilized and removed to obtain the PPC-2OH product with a yield of ~60%. Use the titration method to measure the hydroxyl content, and calculate the relative molecular mass...

Embodiment 2

[0053] Example 2: Preparation of polyimide diaphragm using pyromellitic dianhydride and 4,4'-diaminodiphenyl ether as raw materials

[0054] Add 10mmol of diamine monomer 4,4'-diaminodiphenyl ether and 50mL of N,N-dimethylacetamide into a 150mL round bottom flask, mechanically stir at room temperature under nitrogen atmosphere until completely dissolved, then add 10mmol Pyromellitic dianhydride was reacted at room temperature for 10 hours to carry out polymerization, and after adding 10 mmol of anhydrous potassium carbonate to react for 2 hours, centrifuged to remove unreacted solid particles to obtain polyamic acid potassium salt (PAA-K + ). Concrete reaction process is as shown in reaction formula 2:

[0055]

[0056] Reaction 2 PAA-K + The reaction flow formula

[0057] Weigh 2g of 7wt.% PAA-K in a 50mL centrifuge tube + solution, add 0.15g PPC-2Br and stir quickly to make the mixture uniform to obtain a transparent solution, centrifuge at a speed of 10000r / min for 1...

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Abstract

The invention relates to a method for preparing a polyimide porous diaphragm, wherein a thermally unstable polymer is used as a pore-forming agent, firstly, the thermally unstable polymer reacts withpolyamide acid (PAA) in a solvent to form a copolymer, a polymer film is laid, then, a thermally unstable chain segment is thermally pyrolyzed at a high temperature, and the polyamide acid is imidizedto obtain a polyimide porous diaphragm. According to the method in the invention, the pore-forming agent and the polyamide acid chemically react to achieve molecular-level dispersion; the reactivityof the pore-forming agent and the polyamide acid is high, and the porosity of the diaphragm can be adjusted at will. The diaphragm can be applied to the field of lithium ion and lithium sulfur batteries. The preparation method in the invention has the advantages of being simple, being high in reaction efficiency, and being easy for industrial production; the diaphragm has excellent high temperature resistance performance and good mechanical performance and can improve the electrochemical performance and safety of the battery.

Description

technical field [0001] The invention relates to a series of preparation methods of polyimide porous diaphragms, belonging to the fields of polymer synthesis, energy storage and functional materials. Background technique [0002] As a key component of the battery, the separator is located between the positive electrode and the negative electrode, which can provide a lithium ion transmission channel and prevent contact short circuit in the electron transmission between the positive and negative electrodes. On the premise of ensuring the normal operation of the battery, it is an effective strategy to improve the electrochemical performance of the battery by functionalizing the separator. For example, enhance the mechanical strength and high temperature resistance of the separator to improve the safety of the battery; improve the electrolyte wettability of the separator to promote lithium ion transmission and improve the electrochemical performance of the battery. In addition, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/052C08G73/10C08G81/00H01M50/403H01M50/423H01M50/491
CPCH01M10/052C08G73/1007C08G73/1071C08G81/00H01M50/403H01M50/411Y02E60/10
Inventor 孟跃中唐勖尧杨凯王拴紧肖敏任山韩冬梅
Owner SUN YAT SEN UNIV
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