Method for preparing positive electrode material of lithium sulfur battery

A positive electrode material, lithium-sulfur battery technology, applied in battery electrodes, lithium batteries, positive electrodes, etc., can solve the problem of capacity reduction, achieve the effect of improving electronic conductivity and lithium ion mobility, and increasing reversible specific capacity

Inactive Publication Date: 2019-04-30
江西中汽瑞华新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] (2) Soluble polysulfides: long-chain lithium-sulfur compounds (Li 2 S x , x=4~8) The dissolution leads to a higher polysulfide concentration near the positive electrode, which diffuses out from the positive electrode driven by a concentration gradient, resulting in a decrease in capacity

Method used

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  • Method for preparing positive electrode material of lithium sulfur battery
  • Method for preparing positive electrode material of lithium sulfur battery
  • Method for preparing positive electrode material of lithium sulfur battery

Examples

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Effect test

Embodiment 1

[0031] A preparation method of a lithium-sulfur battery cathode material, the specific preparation process is as follows:

[0032] In the first step, 1.78g Zn(NO 3 ) 2 ·6H 2 O, 0.33g C 8 h 6 o 4 , 0.1g KB and 10mg polyethylene glycol were added to 60mL of DMF, the ultrasonic power was set to 60KHz, and a uniformly dispersed mixed solution was formed after ultrasonic stirring for 30min;

[0033] In the second step, add the mixed solution prepared in the first step into the hydrothermal reaction kettle and place it in an oven, raise the temperature to 135°C at a heating rate of 5°C / min and keep it warm for 24 hours, then cool it down to room temperature naturally, wash and filter the precipitate with DMF After three times, it was placed in a vacuum oven at 150°C for 24 hours to obtain the precursor compound KB@MOF-5;

[0034] In the third step, the precursor compound KB@MOF-5 obtained in the second step is placed in a tube furnace with a nitrogen atmosphere, the nitrogen g...

Embodiment 2

[0037] A preparation method of a lithium-sulfur battery cathode material, the specific preparation process is as follows:

[0038] In the first step, 1.19g Zn(NO 3 ) 2 ·6H 2 O, 0.33g C 8 h 6 o 4 , 0.07g KB and 6mg polyacrylamide were added to 50mL of DMF, the ultrasonic power was set to 50KHz, and a uniformly dispersed mixed solution was formed after ultrasonic stirring for 35min;

[0039] In the second step, add the mixed liquid prepared in the first step into the hydrothermal reaction kettle and place it in an oven, raise the temperature to 110°C at a heating rate of 3°C / min and keep it for 24 hours, then cool it down to room temperature naturally, wash and filter the precipitate with DMF After three times, it was placed in a vacuum oven at 155°C for 16 hours to obtain the precursor complex KB@MOF-5;

[0040] In the third step, the precursor compound KB@MOF-5 obtained in the second step is placed in a tube furnace with a nitrogen atmosphere, the nitrogen gas flow rate ...

Embodiment 3

[0043] A preparation method of a lithium-sulfur battery cathode material, the specific preparation process is as follows:

[0044] In the first step, 1.49g Zn(NO 3 ) 2 ·6H 2 O, 0.33g C 8 h 6 o 4 , 0.08g KB and 8mg hydroxyethyl cellulose were added to 60mL of DMF, the ultrasonic power was set to 70KHz, and a uniformly dispersed mixed solution was formed after ultrasonic stirring for 40min;

[0045] In the second step, add the mixed solution prepared in the first step into the hydrothermal reaction kettle and place it in an oven, raise the temperature to 140°C at a heating rate of 5°C / min and keep it for 24 hours, then cool it down to room temperature naturally, wash and filter the precipitate with DMF After three times, it was placed in a vacuum oven at 160°C for 12 hours to obtain the precursor complex KB@MOF-5;

[0046] In the third step, the precursor compound KB@MOF-5 obtained in the second step is placed in a tube furnace with a nitrogen atmosphere, the nitrogen gas fl...

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Abstract

The invention discloses a method for preparing a positive electrode material of a lithium sulfur battery. The method comprises a step of adding an appropriate amount of zinc nitrate hexahydrate, phthalic acid, ketjen black and a surfactant into N, N-dimethylformamide to prepare a mixed solution and then ultrasonically stirring the mixed solution until the mixed solution is evenly dispersed, a stepof putting the mixed solution into a hydrothermal reaction kettle for hydrothermal reaction to obtain KB@MOF-5, a step of placing KB@MOF-5 into a tube furnace protected by inert gas and obtaining KB@Meso-C after high-temperature carbonization, and a step of thermally fusing active sulfur into a KB@Meso-C composite material through heat treatment in the tube furnace protected by inert gas to obtain KB@Meso-C / S. According to the method, by coating the surface of the positive electrode material with the ketjen black, the dissolution of an intermediate product lithium polysulfide and the shuttlebetween the positive and negative electrodes during the charging and discharging process of the active sulfur in the positive electrode material of the lithium sulfur battery can be effectively relieved, the electronic conductivity and the lithium ion mobility of the positive electrode material of the lithium sulfur battery are improved, and therefore, the reversible specific capacity, the rate performance, the cycle stability and life of the lithium sulfur battery are improved.

Description

technical field [0001] The invention belongs to the field of lithium battery preparation, and relates to a preparation method of a lithium-sulfur battery cathode material. Background technique [0002] The concept of lithium-sulfur batteries was first proposed in the 1960s. As a promising next-generation lithium secondary battery system, lithium-sulfur batteries store and transport energy through reversible electrochemical reactions between lithium and sulfur. In theory, Due to its theoretical capacity of active material sulfur 1675mAh g -1 An order of magnitude higher than conventional batteries, the energy density of lithium-sulfur batteries (2600Whkg -1 ) is five times that of commercial batteries, and the theoretical energy density of traditional lithium-ion battery cathode materials is 350-400Wh kg -1 , the actual energy density is 100~220Wh kg -1 , limiting its application in the field of high-power charging and discharging (such as electric vehicles, static energy ...

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 张小溪陈伟王海文
Owner 江西中汽瑞华新能源科技有限公司
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