Preparation method of lithium-sulfur battery positive electrode material

A cathode material, lithium-sulfur battery technology, applied in battery electrodes, lithium storage batteries, nanotechnology for materials and surface science, etc., can solve the problems of material structure collapse, volume expansion, agglomeration, etc., to reduce agglomeration phenomenon, inhibit Effect of crystal aging and conductivity improvement

Active Publication Date: 2018-09-04
ZHEJIANG FOREVER NEW ENERGY TECH CO LTD +1
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AI Technical Summary

Problems solved by technology

[0003] According to prior art reports, the actual specific energy of lithium-sulfur batteries has reached 350Wh kg -1 ; But at this stage, lithium-sulfur batteries are facing a series of problems: there are mainly defects or problems in the following aspects: 1. Elemental sulfur and discharge product Li 2 S 2 / Li 2 S is an electronic and ion insulator, which increases the battery resistance and polarization; 2. The volume expansion of the positive electrode material during the discharge process causes the material structure to collapse and affects the cycle performance of the battery; The soluble polysulfides, due to the migration and reaction between the positive and negative electrodes due to diffusion, the "shuttle effect" of polysulfides occurs, resulting in the irreversible loss of active materials
For example, the Chinese patent (authorized announcement number: CN104701542B) discloses a preparation method of a composite positive electrode material for an all-solid-state lithium-sulfur battery, comprising dispersing conductive polymer monomers and elemental sulfur in water, adding hydrochloric acid and ammonium persulfate at 0-10 The polymerization reaction is carried out at ℃ to obtain a compound formed by the conductive polymer wrapping the elemental sulfur. After high-temperature heat treatment, the conductive polymer / sulfur composite positive electrode material is obtained. Due to the direct addition of elemental sulfur, agglomeration is prone to occur, and the particle size of the sulfur particles cannot be adjusted. , a defect that leads to unstable properties of the material

Method used

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  • Preparation method of lithium-sulfur battery positive electrode material

Examples

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Embodiment 1

[0025] Conductive polymer monomer solution: Take an appropriate amount of aniline monomer and add it to ethanol solvent, stir rapidly, ultrasonically oscillate, and control the temperature at about 25°C. During the stirring and mixing process, a uniform mixed solution is formed to obtain a concentration of 0.05g / mL The ethanol solution of aniline monomer, standby;

[0026]Polysulfide organic solution: select raw materials according to the raw material ratio of polysulfide organic solution, specifically: take 0.28g flake lithium powder and 5.12g sulfur element, and put them into 1,3 -In a mixed organic solvent of dioxolane and ethylene glycol dimethyl ether (volume ratio 3:1), then, under the constant temperature condition of 60°C, the temperature was controlled and stirred for 48 hours. After the reaction was completed, filter and adjust The amount of solvent, obtains 0.2mol / L maroon lithium polysulfide organic solution, standby;

[0027] Sulfur / conductive polymer composite m...

Embodiment 2

[0031] Conductive polymer monomer solution: Take an appropriate amount of 3,4-ethylenedioxythiophene monomer and add it to n-propanol solvent, stir rapidly and ultrasonically, and control the temperature at about 40°C during the stirring and mixing process to form a uniform mixture to obtain a n-propanol solution of 3,4-ethylenedioxythiophene monomer with a concentration of 0.08g / mL for subsequent use;

[0032] Polysulfide organic solution: select raw materials according to the raw material ratio of polysulfide organic solution, specifically: take 0.28g of powdered lithium powder and 6.4g of sulfur element, and put them into carbitol solvent under the protection of nitrogen , then, control the temperature at 100°C, and carry out the stirring reaction for 12 hours. After the reaction, filter and adjust the amount of solvent, so that a 0.2mol / L maroon lithium polysulfide organic solution is obtained, and set aside;

[0033] Sulfur / conductive polymer composite material: Take 20ml...

Embodiment 3

[0036] Conductive polymer monomer solution: Take an appropriate amount of thiophene monomer and add it to tetrahydrofuran solvent, stir rapidly and ultrasonically, control the temperature at about 35°C during the stirring and mixing process, and form a uniform mixed solution, and prepare a concentration of 1g / mL thiophene Monomer tetrahydrofuran solution, standby;

[0037] Polysulfide organic solution: select raw materials according to the raw material ratio of polysulfide organic solution, specifically: take 22.4g of powdered potassium powder and 6.4g of sulfur element, and put them into ethylene carbonate solvent under the protection of nitrogen In, then, control the temperature at a temperature of 50° C., and carry out stirring reaction for 24 hours. After the reaction is completed, filter, adjust the amount of solvent, and prepare a ethylene carbonate solution to obtain 3.0 mol / L potassium polysulfide for subsequent use. ;

[0038] Sulfur / conductive polymer composite mate...

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Abstract

The invention relates to a preparation method of a lithium-sulfur battery positive electrode material, and belongs to the technical field of preparation of a battery positive electrode material. In order to solve the problem that a traditional sulfur-carbon composite material is easy to agglomerate during the preparation process and the grain size is difficult to control, the preparation method ofthe lithium-sulfur battery positive electrode material is provided. The method comprises the steps of adding an alkali metal element and a sulfur element into an organic solvent for reaction under acondition of inert gas protection to obtain a polysulfide organic solution; and taking a mixed liquid of a conductive polymer monomer and the polysulfide organic solution, adding an acid oxidizing agent solution, adjusting a pH value of the mixed liquid to be neutral or weak acid, and obtaining the sulfur / conductive polymer composite material after full reaction. By the preparation method, nanoscale or submicron-scale sulfur particle can be obtained, an effect of relatively narrow size distribution is achieved, the sulfur utilization ratio and the high-rate performance are improved, and the volume expansion phenomenon of the positive electrode material during the lithiation process is favorably reduced.

Description

technical field [0001] The invention relates to a preparation method of a lithium-sulfur battery cathode material, belonging to the technical field of battery cathode material preparation. Background technique [0002] Lithium-sulfur battery is a kind of lithium battery with sulfur element as the positive electrode of the battery, and the theoretical discharge specific capacity of elemental sulfur can reach 1675mAh / g, which is much higher than that of lithium-ion batteries widely used in commerce. Therefore, the sulfur cathode active material is currently the cathode material with the highest specific capacity, while lithium has the smallest relative atomic mass and the most negative standard electrode potential among metal elements. Therefore, lithium-sulfur batteries have high theoretical discharge voltage, high theoretical discharge specific capacity, and high theoretical specific energy, which are expected to meet the long-term development requirements of electric vehicl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/62H01M10/052B82Y30/00
CPCB82Y30/00H01M4/366H01M4/38H01M4/624H01M10/052Y02E60/10
Inventor 张芳芳赵亚刘桐桐杨冬生翟博刘俊军
Owner ZHEJIANG FOREVER NEW ENERGY TECH CO LTD
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