A kind of preparation method of carbon quantum dot modified lithium-sulfur battery cathode material

A technology of carbon quantum dots and cathode materials, which is applied in the field of preparation of cathode materials for lithium-sulfur batteries modified by carbon quantum dots, to achieve the effects of simple process, reducing battery polarization, improving capacity and cycle stability

Active Publication Date: 2021-09-24
UNIV OF ELECTRONICS SCI & TECH OF CHINA
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, so far, zero-dimensional carbon quantum dots have not been used to design and improve the electrochemical interface of lithium-sulfur batteries. Among them, carbon quantum dots (CDots) are different from two-dimensional graphene and one-dimensional carbon nanotubes. A zero-dimensional carbon nanomaterial with unique properties

Method used

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  • A kind of preparation method of carbon quantum dot modified lithium-sulfur battery cathode material
  • A kind of preparation method of carbon quantum dot modified lithium-sulfur battery cathode material
  • A kind of preparation method of carbon quantum dot modified lithium-sulfur battery cathode material

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Effect test

Embodiment 1

[0025] Step 1: Preparation of polyethylene imine functionalized carbon surface of the quantum dot, the specific steps:

[0026] Polyethyleneimine was placed in a glass vial placed on a heating stage 400 ℃ 50min carbonization treatment is performed, the process ends after the platform is removed from the heated glass vial, cooled to room temperature, and then the glass sample after treatment flask was added deionized water, sonicated for 30min, carbon quantum dots dispersed in deionized water to form a dispersion of carbon quantum dots, the quantum dots carbon dispersion was placed in a dialysis bag and dialyzed to remove the unreacted polyethyleneimine amine, after the dialysis treatment quantum dot carbon dispersion was freeze-dried to obtain the functionalized carbon surface polyethyleneimine quantum dot;

[0027] Step 2: The polyethyleneimine functionalized quantum dot surface of the carbon, sulfur powder, acetylene black and polyvinylidene fluoride as a mass ratio of 2: 10: 5:...

Embodiment 2

[0032] Lithium-sulfur battery was prepared following the procedure of Example 1, only the adjustment in step 3 in the sulfur coating amount of the carbon paper current collector surface was 5.2mg / cm 2 Other steps unchanged. Embodiment lithium-sulfur battery obtained in Example 2 in 6mA / cm 2 For capacity and long cycle coulombic efficiency performance as FIG constant current charge and discharge at a current density Image 6 Indicated.

Embodiment 3

[0034] Lithium-sulfur battery was prepared following the procedure of Example 1, only the adjustment in step 3 in the sulfur coating amount of the carbon paper current collector surface is 4mg / cm 2 Other steps unchanged. Example 3 A lithium-sulfur battery obtained in 6mA / cm 2 Length of the loop 400 for circulating a constant current charge and discharge at a current density attenuation rate of 0.02% per revolution.

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Abstract

The invention provides a method for preparing a positive electrode material of a lithium-sulfur battery modified by carbon quantum dots, and belongs to the field of preparation of the positive electrode material of a lithium-sulfur battery. The present invention uses polyethyleneimine surface-functionalized carbon quantum dots for the preparation of lithium-sulfur battery cathodes, utilizes the adsorption of polyethyleneimine on polysulfide compounds, suppresses the shuttle effect during battery charging and discharging, and ensures lithium-sulfur The long-term cycle performance of the battery. The preparation method of the positive electrode material of the carbon quantum dot modified lithium-sulfur battery disclosed in the present invention has the characteristics of simple and convenient process, and can significantly improve the capacity, rate and cycle performance of the lithium-sulfur battery under the working conditions of high load and high current density. The field of sulfur batteries has potential application value.

Description

Technical field [0001] The present invention is in the field of preparation of lithium-sulfur battery positive electrode material, particularly, to a method for preparing carbon quantum dot lithium-sulfur battery positive electrode material modified. Background technique [0002] Among the lithium-ion electrochemical energy storage systems, lithium-sulfur battery is regarded as a promising next-generation lithium secondary battery, has a theoretical 1675mAh / g specific capacity, the theoretical specific energy of the battery is high 2600Wh / kg and it has great potential. Further, as a positive electrode active material for a lithium sulfur-sulfur battery, with abundant, widely available and low-toxic pollution and many other advantages. However, the lithium-sulfur battery charging and discharging process, the electrolyte-soluble long chain sulfur compound at a concentration gradient driven diffusion of the sulfur of the positive electrode to the negative electrode of lithium, a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/04H01M4/13H01M4/38H01M4/62H01M4/66H01M10/052
CPCH01M4/0404H01M4/13H01M4/38H01M4/625H01M4/663H01M10/052Y02E60/10
Inventor 熊杰胡音雷天宇陈伟闫裔超邬春阳吕晓雪
Owner UNIV OF ELECTRONICS SCI & TECH OF CHINA
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