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Polyamine carbon composite material, slurry, diaphragm, lithium-sulfur battery and preparation method

A carbon composite material and polyamine technology, applied in the fields of lithium-sulfur battery and its preparation, separator, slurry, polyamine carbon composite material, can solve the problems of low heteroatom content, capacity loss, shedding, etc., to improve cycle performance, The effect of improving utilization and enhancing conductivity

Inactive Publication Date: 2020-06-05
SOUTH CHINA NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the development of lithium-sulfur batteries is also subject to some restrictions. Among them, the main problem affecting the cycle performance of lithium-sulfur batteries is that during the charging and discharging process, lithium polysulfide, an intermediate product in lithium-sulfur batteries, will migrate from the positive electrode to the negative electrode, resulting in a "shuttle". effect”, leading to the deterioration of the performance of the negative electrode and the reduction of sulfur in the active material of the positive electrode, resulting in irreversible capacity loss
In traditional technology, oxides, sulfides, etc. are mostly used as doping materials, and the content of heteroatoms in them is low, and the adsorption effect on lithium polysulfide is not strong.
Moreover, such inorganic substances have poor film-forming properties. If such doped materials are combined with organic polymer separators, there will be disadvantages of easy dispersion and shedding.
In addition, after the doped material adsorbs lithium polysulfide, if the adsorbed lithium polysulfide is not allowed to continue to participate in the discharge, it will also lead to the loss of active materials.

Method used

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  • Polyamine carbon composite material, slurry, diaphragm, lithium-sulfur battery and preparation method
  • Polyamine carbon composite material, slurry, diaphragm, lithium-sulfur battery and preparation method

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preparation example Construction

[0030] The present invention also provides a method for preparing a polyamine-carbon composite material, and in one specific embodiment, the following steps are included.

[0031] Step 1, mixing the aqueous solution of polyamine and the dispersion liquid containing carboxylated carbon-based materials to obtain a mixed liquid.

[0032] It is easy to understand that the purpose of mixing the two raw materials in the aqueous solution is to disperse the raw materials more uniformly and to make the two raw materials contact more fully, so the solution can be ultrasonically and / or stirred and dispersed at the same time. Another purpose of mixing in an aqueous solution is that after the polyamine is dissolved in water, the amino groups in it can be hydrolyzed to be positively charged, while the carboxyl groups are ionized in water to be negatively charged, thus, the polyamine can pass through the static electricity between ions Adsorption can easily achieve uniform coating of carboxy...

Embodiment 1

[0047] 1) Mix carboxymethyl chitosan aqueous solution with carboxylated graphene oxide dispersion liquid, perform magnetic stirring for 0.5 h, ultrasonic dispersion for 0.5 h until the mixing is uniform, and control the pH value of the mixed liquid between 6-8. Wherein, the concentration of carboxymethyl chitosan aqueous solution is 1.0g / L, the concentration of graphene oxide dispersion liquid is 5g / L, the volume ratio of carboxymethyl chitosan aqueous solution and carboxylated graphene oxide dispersion liquid is 1:1 .

[0048] 2) Freeze-drying the mixed solution, and grinding until the obvious particles are invisible to the naked eye after drying, to obtain carboxymethyl chitosan-graphene oxide composite material;

[0049] 3) The carboxymethyl chitosan-graphene oxide composite material, acetylene black, and polyvinylidene fluoride were adjusted into a slurry according to the mass ratio of 6:2:2 and coated on one side of the polypropylene diaphragm to obtain carboxymethyl chit...

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Abstract

The invention relates to the technical field of batteries, and particularly to a polyamine carbon composite material, a slurry, a diaphragm, a lithium-sulfur battery and a preparation method. The polyamine carbon composite material comprises a carboxylated carbon-based material serving as a substrate and polyamine serving as an outer surface layer, and the polyamine is uniformly and flatly coatedon the outer side surface and / or the inner pore surface of the carboxylated carbon-based material. The material is rich in amino groups, uniform and stable, can be used in a lithium-sulfur battery, and can effectively adsorb lithium polysulfide in a long cycle process. The invention also provides a preparation method of the material. Furthermore, the invention also discloses a slurry and a diaphragm containing the material, and one side of the diaphragm contains a coating layer formed by removing a solvent from the slurry or a coating layer formed by a polyamine carbon composite material.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a polyamine-carbon composite material, a slurry, a diaphragm, a lithium-sulfur battery and a preparation method. Background technique [0002] The theoretical specific capacity of lithium-sulfur batteries is as high as 1675mAh / g, and the theoretical energy density is as high as 2600Wh / kg, which is much higher than that of lithium-ion batteries commonly used today. In addition, its positive electrode material has rich sulfur reserves, low cost, and is relatively environmentally friendly, making it an ideal new electrode material. However, the development of lithium-sulfur batteries is also subject to some restrictions. Among them, the main problem affecting the cycle performance of lithium-sulfur batteries is that during the charging and discharging process, lithium polysulfide, an intermediate product in lithium-sulfur batteries, will migrate from the positive electrode to the ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M2/16H01M10/052
CPCH01M10/052H01M50/411H01M50/431H01M50/44H01M50/449Y02E60/10
Inventor 李伟善江志彬邢丽丹廖友好陈诗雨简希颖黄锦霞
Owner SOUTH CHINA NORMAL UNIVERSITY