Preparation method of high-stability composite positive electrode material for lithium-sulfur battery

A composite positive electrode material and lithium-sulfur battery technology, which is applied in the field of energy storage, can solve the problems of poor cycle stability, low conductivity, and low capacity utilization rate, and achieve the effects of reducing agglomeration, improving utilization rate, and improving cycle stability

Active Publication Date: 2019-10-25
AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for preparing a high-stability lithium-sulfur battery composite positive electrode material for the defects of poor cycle stability, low conductivity, and low capacity utilization of traditional lithium-sulfur battery positive electrode materials

Method used

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  • Preparation method of high-stability composite positive electrode material for lithium-sulfur battery
  • Preparation method of high-stability composite positive electrode material for lithium-sulfur battery
  • Preparation method of high-stability composite positive electrode material for lithium-sulfur battery

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[0040] The preparation method of the present invention will be further described in detail in conjunction with specific examples below. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

[0041] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

Embodiment 1

[0043] Step 1: Mechanically mix the elemental sulfur powder and Ketjen black according to the mass ratio of 1:0.1 and then add it to the airflow mixer. The BET specific surface area of ​​Ketjen black is 1300m 2 / g, the particle size distribution D was prepared by mixing 50Ketjen black-coated sulfur composite material with a thickness of 50 μm;

[0044] Step 2: fluorinated carbon black (fluorocarbon ratio 0.3, BET specific surface area 200m 2 / g) and polyethylene glycol are ultrasonically dispersed in an aqueous solution at a mass ratio of 1:0.1, subjected to a hydrothermal reaction treatment at 160°C for 20 hours, and the reaction product is suction-filtered, washed, and dried to obtain a carbon-coated carbon fluoride material;

[0045] Step 3: adding the obtained Ketjen Black-coated sulfur composite material and carbon-coated carbon fluoride material in a mass ratio of 1:0.2 into a ball milling tank, and dry ball milling for 3 hours. Then, the above materials were kept in a...

Embodiment 2

[0049] Step 1: Mechanically mix the elemental sulfur powder and the conductive agent according to the mass ratio of 1:0.15, and then add it to the airflow mixer. The mass ratio of the conductive agent is composed of super conductive carbon black: Ketjen black = 0.2:1, and the conductive agent BET The specific surface area is 800m 2 / g, the particle size distribution D was prepared by mixing 50 30μm conductive agent-coated sulfur composite material;

[0050] Step 2: fluorinated graphene (fluorocarbon ratio 0.1, BET specific surface area 200m 2 / g) and sucrose are ultrasonically dispersed in an aqueous solution at a mass ratio of 1:0.05, subjected to a hydrothermal reaction treatment at 350°C for 24 hours, and the reaction product is suction filtered, washed, and dried to obtain a carbon-coated carbon fluoride material;

[0051] Step 3: Add the conductive agent-coated sulfur composite material and the carbon-coated carbon fluoride material obtained above into a ball mill tank ...

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Abstract

The invention provides a preparation method of a high-stability composite positive electrode material for a lithium-sulfur battery, and the method employs carbon-coated carbon fluoride as a functionalcarrier of sulfur, so that the cycling stability, the rate capability, the first discharge capacity and the discharge voltage platform of the composite positive electrode material can be remarkably improved; the utilization rate of the active material in the positive electrode material is improved, and the important significance is realized on prolonging the service life, energy and power performance of the lithium-sulfur battery. By adopting the preparation method disclosed by the invention, two solid-phase products with coated structures can be subjected to ball milling and then are meltedand diffused to enable sulfur to be melted and permeated into two phases, so that the positive electrode material is prepared through combination. The process has the technical advantages that after sulfur is coated with carbon, the sulfur can be more uniformly dispersed in the prepared positive electrode material through ball milling and melting diffusion, thereby reducing the agglomeration of the sulfur; and the coating size can reach the nanoscale. However, conventional mixing of elemental sulfur and a conductive agent cannot effectively coat sulfur, and the sulfur agglomeration phenomenonis serious.

Description

technical field [0001] The invention relates to a preparation method of a high-stability composite cathode material for lithium-sulfur batteries, which belongs to the technical field of energy storage. Background technique [0002] With the development of social economy, people have higher and higher performance requirements for mobile power supplies, and various portable electronic product supporting power supplies are developing in the direction of high specific energy, high power, long life, high safety, and high environmental adaptability. The theoretical specific energy of lithium-sulfur batteries is 2600Wh / kg, which is an important direction for the development of next-generation high-energy-density battery technology. However, the low electronic conductivity of elemental sulfur and its discharge products, and the shuttling side reactions of soluble polysulfide products lead to low capacity utilization efficiency of cathode materials, poor cycle stability, and limited ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052
CPCH01M4/366H01M4/38H01M4/625H01M4/628H01M10/052H01M2004/021H01M2004/028Y02E60/10
Inventor 彭思侃王晨燕绍九洪起虎
Owner AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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