Preparation method for fluorine-doped three-dimensional structured positive electrode material of lithium-sulfur battery

A lithium-sulfur battery, three-dimensional structure technology, applied in battery electrodes, lithium batteries, structural parts, etc., can solve the problems of slowing electrochemical reaction kinetics, reducing the utilization rate of sulfur active materials, and safety of lithium-sulfur batteries, etc. Achieve the effect of reducing the shuttle effect, conducive to electrical conductivity, and shortening the conduction distance

Active Publication Date: 2016-05-25
常熟东南高新技术创业服务有限公司
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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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  • Preparation method for fluorine-doped three-dimensional structured positive electrode material of lithium-sulfur battery

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Effect test

Embodiment 1

[0019] (1) Add 10mg of graphite oxide into 10mL of water and sonicate for 10 minutes to form a 1g / L graphene oxide suspension;

[0020] (2) Add 1 mg of tetrabutylammonium fluoride to the graphene oxide suspension, then transfer it to a hydrothermal kettle for reaction, and react at 160°C for 6 hours. After the reaction is completed, wash with ethanol, wash with water, and then freeze-dry to obtain a three-dimensional fluoride doped graphene;

[0021] (3) Take 10 mg of the three-dimensional fluorine-doped graphene obtained in (2) and 5 mg of Ketjen black and add it to 15 mL of N-methylpyrrolidone and ultrasonically form a 1 g / L suspension;

[0022] (4) Add 150mg of elemental sulfur to 15mL of N-methylpyrrolidone and sonicate at a certain 40°C until the elemental sulfur is completely dissolved to form a 10g / L suspension;

[0023] (5) Mix the two suspensions obtained in (4) and (3), stir evenly, then slowly add 90 mL of distilled water under stirring, centrifuge, wash with water...

Embodiment 2

[0025] (1) Add 10 mg of graphite oxide to 1 mL of water and sonicate for 60 minutes to form a 10 g / L graphene oxide suspension;

[0026] (2) Add 10mg of tetrabutylammonium fluoride to the graphene oxide suspension, then transfer it to a hydrothermal kettle for reaction, and react at 200°C for 1 hour. After the reaction is completed, wash with ethanol, wash with water, and then freeze-dry to obtain a three-dimensional fluoride doped graphene;

[0027] (3) Take 10 mg of three-dimensional fluorine-doped graphene obtained in (2) and 0.5 mg of Ketjen Black and add it to 2.1 mL of N-methylpyrrolidone and ultrasonically form a 5 g / L suspension;

[0028] (4) Add 210mg of elemental sulfur to 14mL of N-methylpyrrolidone and sonicate at 50°C until the elemental sulfur is completely dissolved to form a 15g / L suspension;

[0029] (5) Mix the two suspensions obtained in (4) and (3), stir evenly, then slowly add 80.5 mL of distilled water under stirring, centrifuge, wash with water, and dry...

Embodiment 3

[0031] (1) Add 10mg graphite oxide into 5mL water and sonicate for 30 minutes to form a 2g / L graphene oxide suspension;

[0032] (2) Add 5mg of tetrabutylammonium fluoride to the graphene oxide suspension, then transfer it to a hydrothermal kettle for reaction, and react at 180°C for 3 hours. After the reaction is completed, wash with ethanol, wash with water, and then freeze-dry to obtain a three-dimensional fluoride doped graphene;

[0033] (3) Take 10 mg of three-dimensional fluorine-doped graphene obtained in (2) and 1 mg of Ketjen black and add it to 5.5 mL of N-methylpyrrolidone and ultrasonically form a 2 g / L suspension;

[0034] (4) Add 132mg of elemental sulfur to 11mL of N-methylpyrrolidone and sonicate at 45°C until the elemental sulfur is completely dissolved to form a 12g / L suspension;

[0035] (5) Mix the two suspensions obtained in (4) and (3), stir evenly, then slowly add 66 mL of distilled water under stirring, centrifuge, wash with water, and dry to obtain a...

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Abstract

The invention provides a preparation method for a fluorine-doped three-dimensional structured positive electrode material of a lithium-sulfur battery. The preparation method comprises the following steps of (1), adding graphite oxide into water for performing ultrasonic processing to form a graphene oxide suspension liquid; (2), adding tetrabutylammonium fluoride to the graphene oxide suspension liquid, then transferring to a hydrothermal kettle to perform a hydrothermal reaction, after the reaction is completed, performing ethyl alcohol washing, water washing, freezing and drying to obtain three-dimensional fluorine-doped graphene; (3), adding the obtained three-dimensional fluorine-doped graphene and ketjen black into N-methyl pyrrolidone for performing an ultrasonic reaction to form a suspension liquid; (4), adding elemental sulfur to the N-methyl pyrrolidone for performing an ultrasonic reaction until the elemental sulfur is fully dissolved to form a suspension liquid; and (5), mixing the obtained two kinds of suspension liquid, uniformly stirring, slowly adding distilled water while stirring, and then performing centrifuging, water washing, and drying to obtain the three-dimensional structured positive electrode material of the lithium-sulfur battery. Due to the preparation method, the cycling life of the lithium-sulfur battery is prolonged.

Description

technical field [0001] The invention relates to the synthesis of nano-carbon materials, in particular to a preparation method of a lithium-sulfur battery cathode material. 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 2.4V and 2.1V), but their electrochemical reaction mechanism is relatively complicated. Lithium-sulfur batteries have the advantages of high specific energy (2600Wh / kg), high specific capacity (1675mAh / 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 electro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/583H01M4/62H01M4/36H01M10/052
CPCH01M4/362H01M4/583H01M4/625H01M10/052Y02E60/10
Inventor 钟玲珑肖丽芳
Owner 常熟东南高新技术创业服务有限公司
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