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Polyacrylonitrile/fluorinated graphene oxide/Celgard composite membrane

A technology of polyacrylonitrile and composite diaphragm, which is applied in the direction of separator/film/diaphragm/spacer components, electrical components, circuits, etc., and can solve the problems of reducing the utilization rate of sulfur active materials, slow migration speed, and lithium-sulfur battery safety, etc. problem, achieve the effect of reducing the shuttle effect and increasing the lifespan

Inactive Publication Date: 2017-07-07
SHENZHEN PEICHENG TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This phenomenon, known as the shuttle effect, reduces the availability of sulfur active species
At the same time insoluble Li 2 S and Li 2 S 2 Deposited on the surface of the lithium negative electrode, which further deteriorates the performance of the lithium-sulfur battery; (3) the final product of the reaction, Li 2 S is also an electronic insulator and will be deposited on the sulfur electrode, while lithium ions migrate slowly in solid lithium sulfide, slowing down the electrochemical reaction kinetics; (4) sulfur and the final product Li 2 The density of S is different. When sulfur is lithiated, the volume expands by about 79%, which easily leads to Li 2 Pulverization of S, causing safety problems in lithium-sulfur batteries
The above deficiencies restrict the development of lithium-sulfur batteries, which is also a key issue that needs to be solved in current research on lithium-sulfur batteries.

Method used

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  • Polyacrylonitrile/fluorinated graphene oxide/Celgard composite membrane
  • Polyacrylonitrile/fluorinated graphene oxide/Celgard composite membrane
  • Polyacrylonitrile/fluorinated graphene oxide/Celgard composite membrane

Examples

Experimental program
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Effect test

Embodiment 1

[0020] (1) Put graphite oxide into a muffle furnace and heat it to 50°C for 60 minutes. The reaction atmosphere is nitrogen-fluorine mixed gas containing 5% fluorine gas. After the reaction is completed, cool naturally to obtain fluorinated graphite oxide;

[0021] (2) Add 10g of fluorinated graphite oxide into 100g of N-methylpyrrolidone and disperse ultrasonically for 5 hours to form a suspension;

[0022] (3) Add 2g of commercial polyacrylonitrile powder into 20g of N-methylpyrrolidone, swell for 24 hours, heat to 50°C, and stir for 5 hours to obtain a polyacrylonitrile solution;

[0023] (4) Slowly add the suspension into the polyacrylonitrile solution, and react with mechanical stirring for 1 hour to obtain the polyacrylonitrile / fluorinated graphite oxide spinning stock solution, which is electrospun on a Celgard diaphragm to obtain polyacrylonitrile / fluorinated graphite oxide Graphene / Celgard composite separator.

Embodiment 2

[0025] (1) Put graphite oxide into a muffle furnace and heat it to 200°C for 10 minutes to react. The reaction atmosphere is a nitrogen-fluorine mixed gas containing 10% fluorine gas. After the reaction is completed, it is naturally cooled to obtain fluorinated graphite oxide;

[0026] (2) Add 10g of fluorinated graphite oxide into 1000g of dimethyl sulfoxide, and ultrasonically disperse for 0.5 hours to form a suspension;

[0027] (3) Add 10g of commercial polyacrylonitrile powder into 1000g of dimethyl sulfoxide, swell for 24 hours, heat to 50°C, and stir for 0.5 hours to obtain a polyacrylonitrile solution;

[0028] (4) Slowly add the suspension to the polyacrylonitrile solution, and react with mechanical stirring for 5 hours to obtain a polyacrylonitrile / fluorinated graphite oxide spinning stock solution, which is electrospun on a Celgard diaphragm to obtain polyacrylonitrile / fluorinated graphite oxide Graphene / Celgard composite separator.

Embodiment 3

[0030] (1) Put graphite oxide into a muffle furnace and heat it to 100°C for 30 minutes to react. The reaction atmosphere is a nitrogen-fluorine mixed gas containing 7% fluorine gas. After the reaction is completed, it is naturally cooled to obtain fluorinated graphite oxide;

[0031] (2) Add 10g of fluorinated graphite oxide into 500g of N,N-dimethylformamide, and ultrasonically disperse for 3 hours to form a suspension;

[0032] (3) Add 5g of commercial polyacrylonitrile powder to 250g of N,N-dimethylformamide, swell for 24 hours, heat to 65°C, and stir for 2.5 hours to obtain a polyacrylonitrile solution;

[0033] (4) Slowly add the suspension into the polyacrylonitrile solution, and react with mechanical stirring for 3 hours to obtain a polyacrylonitrile / fluorinated graphite oxide spinning stock solution, which is electrospun on a Celgard diaphragm to obtain polyacrylonitrile / fluorinated graphite oxide Graphene / Celgard composite separator.

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Abstract

The invention provides a polyacrylonitrile / fluorinated graphene oxide / Celgard composite membrane. The polyacrylonitrile / fluorinated graphene oxide / Celgard composite membrane comprises a commercial Celgard membrane and a polyacrylonitrile / fluorinated graphene oxide layer on the surface of the commercial Celgard membrane, wherein the thickness of the polyacrylonitrile / fluorinated graphene oxide layer is 1 micron-10 microns and the mass ratio of polyacrylonitrile to fluorinated graphene oxide in the polyacrylonitrile / fluorinated graphene oxide layer is (0.2-1) to 1; and the mass percent of oxygen in the fluorinated graphene oxide is 1%-20% and the mass percent of fluorine in the fluorinated graphene oxide is 1%-20%. A nitrile group on the polyacrylonitrile in the polyacrylonitrile / fluorinated graphene oxide layer, and oxygen and fluorine on the surface of the fluorinated graphene oxide are strong polar groups, and can form strong chemical adsorption on polysulfide formed in a charging / discharging process; and the effect of effectively preventing the polysulfide from penetrating through the membrane and reaching a negative electrode is realized, a shuttle flying effect is reduced and the service life of a lithium-sulfur battery is prolonged.

Description

technical field [0001] The invention relates to the field of lithium-sulfur batteries, in particular to a lithium-sulfur battery diaphragm. Background technique [0002] A lithium-sulfur battery is a battery system in which metallic lithium is used as the negative electrode and elemental sulfur is used as the positive electrode. Lithium-sulfur batteries have two discharge platforms (about 2.4 V and 2.1 V), but their electrochemical reaction mechanism is relatively complicated. Lithium-sulfur batteries have the advantages of high specific energy (2600 Wh / kg), high specific capacity (1675 mAh / g), and low cost, and are considered to be a promising new generation of batteries. However, at present, there are problems such as low utilization of active materials, low cycle life and poor safety, which seriously restrict the development of lithium-sulfur batteries. The main reasons for the above problems are as follows: (1) elemental sulfur is an electronic and ion insulator, and i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/14H01M2/16H01M50/403H01M50/44H01M50/446H01M50/451
CPCH01M50/409H01M50/411H01M50/44H01M50/403Y02E60/10
Inventor 钟玲珑
Owner SHENZHEN PEICHENG TECH CO LTD
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