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Method for preparing composite separator for lithium sulfur battery

A composite diaphragm, lithium-sulfur battery technology, applied in lithium batteries, battery pack parts, non-aqueous electrolyte batteries, etc., can solve the problem that the flame retardant performance cannot be well improved, and achieve the suppression of the shuttle effect and the improvement of heat resistance. performance, the effect of improving safety performance

Active Publication Date: 2019-10-18
QUZHOU RES INST OF ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] As the battery safety problem is one of the main problems of lithium-sulfur batteries at present, and the current diaphragm modification is generally chosen to be coated on commercial diaphragms or PAN diaphragms, the heat resistance and flame retardancy of the diaphragm cannot be well improved. Therefore, it is also of great significance to choose a base film with flame retardancy and heat resistance.

Method used

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  • Method for preparing composite separator for lithium sulfur battery
  • Method for preparing composite separator for lithium sulfur battery

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preparation example Construction

[0030] The preparation method of composite diaphragm provided by the invention may further comprise the steps:

[0031] (1) React an equimolar amount of diamine with dianhydride to obtain a polyamic acid solution; take a part of the polyamic acid solution as a spinning solution for spinning to form a film, and obtain a polyimide spinning solution after thermal imidization treatment. Silk-based membranes; specifically include:

[0032] (1.1) Add the diamine into the solvent, stir in a cold trap at -3°C under the protection of nitrogen until dissolved; then add the dianhydride into the diamine solution in four times; after reacting for 12 hours, a polyamic acid solution is obtained; The solvent is N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc) or N-methylpyrrolidone (NMP);

[0033] The diamine is any one or more of the following: p-phenylenediamine, 4,4'-diaminodiphenyl ether, biphenylenediamine, 2,2-bis(3-amino-4-hydroxyphenyl ) hexafluoropropane, 4,4'-diaminodiphe...

Embodiment 1

[0042] An example of the preparation of a separator sandwiched by a nitrogen-doped carbide film.

[0043]Preparation of diaphragm: Weigh 2.0024g of 4,4'-diaminodiphenyl ether, dissolve 4,4'-diaminodiphenyl ether in 40mL of DMF in a cold trap at -3°C under a nitrogen atmosphere, and Equimolar amounts of pyromellitic dianhydride were added into the solution four times every half hour. Specifically, 0.7271 g was added for the first and second times, 0.3635 g was added for the third and fourth times, and reacted for 12 hours to obtain poly Amic acid solution. Then the polyamic acid solution was subjected to electrospinning, the electrospinning temperature was 32°C, the spinning voltage was 17KV, the distance between the spinning needle and the receiver was 20cm, and the spinning time was 2h, and the polyamic acid obtained by spinning was The non-woven separator was dried overnight in an oven at 60 °C, and then the polyamic acid non-woven film was placed in N 2 Under protection, ...

Embodiment 2

[0050] Preparation of diaphragm: Weigh 2.0024g of 4,4'-diaminodiphenyl ether, dissolve 4,4'-diaminodiphenyl ether in DMF in a cold trap at -3°C under a nitrogen atmosphere, and equimolarly A certain amount of 3,3',4,4'-biphenyltetracarboxylic dianhydride was added into the solution four times every half hour, specifically, 0.9807g was added for the first and second times, and 0.9807g was added for the third and fourth times respectively. Add 0.4904g and react for 12 hours to obtain a polyamic acid solution, then electrospin the polyamic acid solution, the electrospinning temperature is 32°C, the spinning voltage is 17KV, and the distance between the spinning needle and the receiver is 20cm , spinning for 2h, the polyamic acid non-woven membrane obtained by spinning was dried overnight in an oven at 60°C, and then dried under N 2 Under protection, the temperature is raised in steps of 5°C / min, and the temperature is kept at 100°C, 200°C, and 300°C for 1 hour respectively, and t...

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Abstract

The present invention relates to the technology of lithium sulfur batteries, and aims to provide a method for preparing a composite separator for a lithium sulfur battery. The method comprises the following steps: a polyamide acid solution is obtained by reaction of diamine and dianhydride, which is used as a spinning solution for spinning film formation; polyimide spinning base film is obtained after thermal imidization treatment; the polyamic acid solution is mixed with small nitrogen-containing molecules and graphene oxide and then subjected to spinning film formation, and after thermal imidization and carbonization treatment, self-supporting reduced graphene oxide / nitrogen-doped carbon nanofiber is obtained; the polyimide spinning base film and the reduced graphene oxide / nitrogen-dopedcarbon nanofiber are taken; and the two layers are laminated and sliced to obtain the composite separator for assembling the lithium sulfur battery. The separator of the invention has good heat resistance and flame resistance, can greatly improve the safety performance of the lithium sulfur battery, reduces the internal resistance of the battery and enhances the electrochemical performance of thebattery. High charge and discharge specific capacity, high cyclicity and safety of the lithium sulfur battery are realized.

Description

technical field [0001] The invention relates to lithium-sulfur battery technology, in particular to a preparation method for a composite diaphragm used in lithium-sulfur batteries. Background technique [0002] Lithium-sulfur batteries are ideal substitutes for today's lithium-ion batteries due to the high theoretical specific capacity of sulfur (approximately 1675mAh g -1 ), and high energy density (2600Wh kg -1 ) and sulfur is cheap, easy to get, rich in natural reserves, and environmentally friendly, and has become an ideal battery cathode material. However, there is still a certain distance from industrialization of lithium-sulfur batteries at present, mainly due to the problem of soluble polysulfide shuttling and battery safety. However, the shuttle effect of soluble polysulfides seriously affects the electrochemical performance of lithium-sulfur batteries. [0003] At present, the separators used in lithium-sulfur batteries are mostly commercial PP or PE separators, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M10/052
CPCH01M10/052H01M50/40H01M50/431H01M50/44H01M50/449Y02E60/10
Inventor 张庆华李媛媛詹晓力陈丰秋程党国
Owner QUZHOU RES INST OF ZHEJIANG UNIV
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