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Preparation method of composite cathode material of lithium-sulfur battery

A composite positive electrode material, lithium-sulfur battery technology, applied in the direction of battery electrodes, lithium batteries, non-aqueous electrolyte batteries, etc., can solve the problems of destroying structural stability, degradation of cycle performance, and reduction of Coulombic efficiency, etc., to achieve low prices and increase energy Density, the effect of improving production efficiency

Active Publication Date: 2019-04-26
LIAONING TECHNICAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still many problems in the practical application of lithium-sulfur batteries, such as the low conductivity of sulfur and the dramatic volume change of sulfur-containing materials during charging and discharging, which will destroy the stability of its structure and cause the positive electrode material to be damaged during the cycle. Pulverizes and falls off from the current collector, and at the same time, the polysulfides generated during the cycle will produce a "shuttle effect", which will cause a sharp attenuation of the specific capacity, reduce the Coulombic efficiency, and lead to a decrease in cycle performance

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A preparation method of a lithium-sulfur battery composite positive electrode material is carried out according to the following steps:

[0027] (1) be 10:1 by mass proportion, get graphyne and dicyandiamide to mix, form mixture;

[0028] (2) heat-treating the mixture at 400°C for 36 hours to form a composite product;

[0029] (3) Using physical vapor deposition or chemical vapor deposition, according to the mass ratio, elemental sulfur: composite product = 1:1, depositing elemental sulfur on the composite product to obtain a deposition product;

[0030] (4) dissolving graphene oxide in deionized water to prepare a graphene oxide solution, the mass concentration of the graphene oxide solution is 10%;

[0031] (5) According to the proportioning ratio, deposition product: graphene oxide solution=10:1, stir, the deposition product is dispersed in the graphene oxide solution, and the deposition product graphene oxide emulsion is obtained;

[0032] (6) Dry the deposited pr...

Embodiment 2

[0034] A preparation method of a lithium-sulfur battery composite positive electrode material is carried out according to the following steps:

[0035] (1) be 1:1 by mass proportion, get graphyne and melamine to mix, form mixture;

[0036] (2) heat-treating the mixture at 600°C for 10 hours to form a composite product;

[0037] (3) Using physical vapor deposition or chemical vapor deposition, according to the mass ratio, elemental sulfur: composite product = 5:1, depositing elemental sulfur on the composite product to obtain a deposition product;

[0038] (4) dissolving graphene oxide in deionized water to prepare a graphene oxide solution, the mass concentration of the graphene oxide solution is 30%;

[0039] (5) According to the proportioning ratio, deposition product: graphene oxide solution=5:1, stir, and the deposition product is dispersed in the graphene oxide solution to obtain the deposition product graphene oxide emulsion;

[0040] (6) Dry the deposited product grap...

Embodiment 3

[0042] A preparation method of a lithium-sulfur battery composite positive electrode material is carried out according to the following steps:

[0043] (1) be 1:10 by mass proportion, get graphyne and urea to mix, form mixture;

[0044] (2) heat-treating the mixture at 800°C for 2 hours to form a composite product;

[0045] (3) Using physical vapor deposition or chemical vapor deposition, according to the mass ratio, elemental sulfur: composite product = 10:1, depositing elemental sulfur on the composite product to obtain a deposition product;

[0046] (4) dissolving graphene oxide in deionized water to prepare a graphene oxide solution, the mass concentration of the graphene oxide solution is 60%;

[0047] (5) According to the proportioning ratio, the deposition product: graphene oxide solution=1:1, stir, and the deposition product is dispersed in the graphene oxide solution to obtain the deposition product graphene oxide emulsion;

[0048] (6) Dry the deposited product gra...

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PUM

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Abstract

The invention discloses a preparation method of a composite cathode material of a lithium-sulfur battery. The preparation method comprises the following steps: mixing graphdiyne with a C3N4 precursorin proportion to form a mixture, and then carrying out heat treatment to form a composite product; depositing elemental sulfur on the composite product by adopting a vapor deposition method to obtaina deposition product; preparing a graphene oxide solution with corresponding concentration, dispersing a deposition product in the graphene oxide solution to obtain a deposition product graphene oxideemulsion, and drying to prepare the composite cathode material of the lithium-sulfur battery. The adopted graphdiyne has excellent physical and chemical properties, C3N4 has excellent sulfur fixationperformance, nano-scale sulfur particles are obtained through vapor deposition, graphene oxide is added, high-temperature treatment is carried out, and graphene is generated in situ and uniformly. The method is simple and suitable for large-scale production, the sulfur particles are closely combined with the C3N4, the graphdiyne and graphene, and the prepared cathode material has excellent electrochemical performance.

Description

Technical field: [0001] The invention belongs to the technical field of new energy materials, and in particular relates to a preparation method of a lithium-sulfur battery composite cathode material. Background technique: [0002] With the rapid development of smart grid, space technology and electric vehicles, the development of chemical energy storage devices with high capacity, long cycle life, low cost and environmental friendliness has become a research hotspot. Lithium metal is the negative electrode, elemental sulfur or For a lithium-sulfur battery with a sulfur-containing material as the positive electrode, the theoretical capacity of the lithium-sulfur battery is calculated to be 1675mAh / g, and the theoretical energy density is 2567Wh / Kg based on the amount of electricity that can be provided by the unit mass of elemental sulfur being completely reduced to lithium sulfide. Compared with traditional lithium-ion batteries, lithium-sulfur batteries meet the above requi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052
CPCH01M4/366H01M4/38H01M4/625H01M4/628H01M10/052Y02E60/10
Inventor 陈跃辉马红岩董伟刘凤霞杨绍斌
Owner LIAONING TECHNICAL UNIVERSITY