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Preparation method for three-dimensional carbon nanotube/nitrogen-doped graphene/sulfur electrode slice

A technology of nitrogen-doped graphene and carbon nanotubes, applied in battery electrodes, circuits, electrical components, etc., can solve the problem of slowing down the kinetics of electrochemical reactions, reducing the utilization rate of sulfur active materials, and deteriorating the performance of lithium-sulfur batteries, etc. problem, achieve the effect of reducing the shuttle effect, increasing the conductivity, and improving the cycle life

Inactive Publication Date: 2016-05-25
钟玲珑
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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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  • Preparation method for three-dimensional carbon nanotube/nitrogen-doped graphene/sulfur electrode slice

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] (1) Add 1g of carbon nanotubes with a diameter of 20nm and a length of 1um, 1g of graphite oxide, and 1g of polyacrylonitrile to 100mL of N-methylpyrrolidone, stir evenly and ultrasonically react for 30 minutes, and then coat the mixed slurry on aluminum foil , and vacuum-dried to obtain electrode sheets.

[0017] (2) Put the obtained electrode sheet into an ammonia-protected muffle furnace, slowly raise the temperature to 400°C at a rate of 3°C / min, react for 5 hours, and cool naturally.

[0018] (3) Completely insert the electrode sheet obtained in (2) into 2mol / L Na 2 S 2 o 3 In the solution, stand still for 30 minutes, then slowly add 1mol / L hydrochloric acid dropwise to the solution until the solution pH=7.5, take out the electrode sheet, and obtain the positive electrode sheet after drying.

Embodiment 2

[0020] (1) Add 1g of carbon nanotubes with a diameter of 100nm and a length of 20um, 0.8g of graphite oxide, and 1.2g of polyacrylonitrile into 100mL of N-methylpyrrolidone, stir evenly and ultrasonically react for 120 minutes, and then coat the mixed slurry on Aluminum foil, vacuum drying to obtain the electrode sheet.

[0021] (2) Put the obtained electrode sheet into an inert gas-protected muffle furnace, slowly raise the temperature to 500°C at a rate of 5°C / min, react for 0.5 hours, and cool naturally.

[0022] (3) Completely insert the electrode sheet obtained in (2) into 0.5mol / L Na 2 S 2 o 3 In the solution, stand still for 60 minutes, then slowly add 1 mol / L hydrochloric acid dropwise to the solution until the solution pH=6.5, take out the electrode sheet, and obtain the positive electrode sheet after drying.

Embodiment 3

[0024] (1) Add 1g of carbon nanotubes with a diameter of 30nm and a length of 10um, 1.2g of graphite oxide, and 0.8g of polyacrylonitrile to 100mL of N-methylpyrrolidone, stir evenly and ultrasonically react for 60 minutes, and then coat the mixed slurry on Aluminum foil, vacuum drying to obtain the electrode sheet.

[0025] (2) Put the obtained electrode sheet into an ammonia-protected muffle furnace, slowly raise the temperature to 450°C at a rate of 4°C / min, react for 1 hour, and cool naturally.

[0026] (3) Completely insert the electrode sheet obtained in (2) into 1mol / L Na 2 S 2 o 3 In the solution, stand still for 50 minutes, then slowly add 1mol / L hydrochloric acid dropwise to the solution until the pH of the solution is 7, take out the electrode sheet, and obtain the positive electrode sheet after drying.

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Abstract

The invention provides a preparation method for a three-dimensional carbon nanotube / nitrogen-doped graphene / sulfur electrode slice. The preparation method comprises the following steps of (1) adding the carbon nanotube, graphite oxide and polyacrylonitrile to N-methyl pyrrolidone, performing an ultrasonic reaction, coating an aluminium foil with mixed paste, and performing vacuum drying to obtain the electrode slice; (2) putting the obtained electrode slice into a muffle furnace under ammonia gas protection, heating to 400-500 DEG C, and naturally cooling; and (3) enabling the electrode slice obtained in the step (2) to be fully inserted into a Na2S2O3 solution, and slowly adding hydrochloric acid to the solution in a dropwise manner until the PH value of the solution reaches 6.5-7.5, taking out the electrode slice, and drying the electrode slice to obtain a positive plate. The electrode slice prepared by the invention can be directly used for the positive electrode of a lithium-sulfur battery without requiring a conductive agent and a binder, so that the cost of the electrode is greatly lowered.

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 el...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/583H01M4/139H01M10/052
CPCH01M4/139H01M4/362H01M4/38H01M4/5835H01M10/052Y02E60/10
Inventor 钟玲珑肖丽芳
Owner 钟玲珑
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