Preparation method for boron-nitrogen-co-doped three-dimensional structured positive electrode material of lithium-sulfur battery

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

Inactive Publication Date: 2016-05-25
钟玲珑
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  • Abstract
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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 boron-nitrogen-co-doped three-dimensional structured positive electrode material of lithium-sulfur battery

Examples

Experimental program
Comparison scheme
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 100mL of ammonia water with a mass concentration of 25% to the graphene oxide suspension, then add 100mg of sodium borohydride, then transfer to a hydrothermal kettle for reaction, and react at 160°C for 6 hours. After the reaction is completed, wash with ethanol and water , and then freeze-dried to obtain three-dimensional boron-nitrogen co-doped graphene;

[0021] (3) Take 10 mg of the three-dimensional boron-nitrogen co-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 9...

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 500mL of ammonia water with a mass concentration of 25% to the graphene oxide suspension, then add 300mg of sodium borohydride, then transfer to a hydrothermal kettle for reaction, and react at 200°C for 1 hour. After the reaction is completed, wash with ethanol and water , and then freeze-dried to obtain three-dimensional boron-nitrogen co-doped graphene;

[0027] (3) Take 10 mg of the three-dimensional boron-nitrogen co-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 ...

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 200mL of ammonia water with a mass concentration of 25% to the graphene oxide suspension, then add 200mg of sodium borohydride, then transfer to a hydrothermal kettle for reaction, and react at 180°C for 3 hours. After the reaction is completed, wash with ethanol and water , and then freeze-dried to obtain three-dimensional boron-nitrogen co-doped graphene;

[0033] (3) Take 10 mg of three-dimensional boron-nitrogen co-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 wa...

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Abstract

The invention provides a preparation method for a boron-nitrogen-co-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 ammonium hydroxide to the graphene oxide suspension liquid, and then adding sodium borohydride to the graphene oxide suspension liquid to obtain three-dimensional boron-nitrogen-co-doped graphene; (3), adding the three-dimensional boron-nitrogen-co-doped graphene obtained in the step (2) and ketjen black into N-methyl pyrrolidone for performing an ultrasonic reaction to form a suspension liquid; (4), adding 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 two kinds of suspension liquid obtained in the step (4) and the step (3), and then adding distilled water to obtain the three-dimensional structured positive electrode material of the lithium-sulfur battery. Due to sulfur adsorption by the synergistic effects of boron atoms and nitrogen atoms in the boron-nitrogen-co-doped graphene, the shuttle effect is lowered, so that the cycling life of the lithium-sulfur battery is prolonged.

Description

technical field [0001] The invention relates to the synthesis of nanometer materials, in particular to a preparation method of a cathode material of a lithium-sulfur battery. 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 elec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/62H01M10/052
CPCH01M4/364H01M4/62H01M4/625H01M10/052Y02E60/10
Inventor 钟玲珑肖丽芳
Owner 钟玲珑
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