Method for preparing lithium-sulfur battery positive pole material

A positive electrode material, lithium-sulfur battery technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of difficult utilization of active materials, reduce battery life, and restrict commercial applications, etc., to achieve good cycle stability, inhibit Effect of agglomeration and improvement of electrical conductivity

Inactive Publication Date: 2015-11-11
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But at the same time, there are some problems that restrict its commercial application.
[0003] First of all, elemental sulfur is an insulator of electrons and ions, and it is difficult to use active materials.
In addition, lithium polysulfide (Li 2 S x , 3≤x≤6) will dissolve in the electrolyte and cause the loss of active materials, reducing the service life of the battery
The dissolved lithium polysulfide migrates to the negative electrode, reacts with the metal lithium negative electrode, and self-discharges, resulting in a lower Coulombic efficiency and accelerating the corrosion of the lithium negative electrode

Method used

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  • Method for preparing lithium-sulfur battery positive pole material
  • Method for preparing lithium-sulfur battery positive pole material
  • Method for preparing lithium-sulfur battery positive pole material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 1), the preparation of graphite oxide:

[0039] Add 39mL of concentrated sulfuric acid (98%) into a three-necked flask, then weigh 2.5g of potassium persulfate and 2.5g of phosphorus pentoxide and add them to the three-necked flask successively, mix well; then add 5g of natural flake graphite powder (325 mesh), Then place it in a constant temperature water bath and react for 6 hours under stirring at 80°C; slowly pour the reactant into a beaker filled with 700ml of deionized water for dilution, transfer the diluted liquid to a Buchner funnel for filtration, and wash until the filtrate into neutral. The obtained filter cake was dried under vacuum at 100° C. for 10 h, and the obtained solid matter was pre-oxidized graphite.

[0040] 2), the preparation of graphite oxide:

[0041]Weigh 2.5g of pre-oxidized graphite and 1.25g of sodium nitrate powder into a round-bottomed flask filled with 57.5mL of concentrated sulfuric acid (98%), slowly add 7.5g of potassium permangana...

Embodiment 2

[0053] 1), the preparation of graphite oxide:

[0054] Mix 3g of natural flake graphite (200 mesh) with 2.5g of potassium persulfate and 2.5g of phosphorus pentoxide into a three-necked flask filled with 50mL of concentrated sulfuric acid (98%), mix well under magnetic stirring conditions, and then place at constant temperature In a water bath, react at 80°C for 6 hours; after the reaction, dilute with deionized water, then filter and wash with a Buchner funnel until the filtrate becomes neutral. The filter cake was dried under vacuum at 80° C. for 20 h, and the obtained solid matter was pre-oxidized graphite.

[0055] 2), the preparation of graphite oxide:

[0056] Weigh 2.5g of pre-oxidized graphite and 1.25g of sodium nitrate powder into a round-bottomed flask filled with 57.5mL of concentrated sulfuric acid (98%), slowly add 10g of potassium permanganate under ice-water bath conditions, and control the temperature of the reaction system below 20°C, after 3 hours of react...

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Abstract

The invention discloses a method for preparing a lithium-sulfur battery positive pole material. Graphite oxide is prepared through the Hummers method, graphene dispersion liquid is obtained through chemical reduction, graphene / nano metallic oxide / nano sulfur mixed dispersion liquid is subjected to fast cooling, curing, freezing, drying and thermal treatment, and a nano metallic oxide / nano sulfur composite material where graphene is wound is prepared and serves as the lithium-sulfur battery positive pole material. Nano sulfur particles are evenly attached to the surface of the graphene, and the utilization rate of active substances is greatly increased through sulfur in the nano size. The graphene of a wound structure can effectively inhibit graphene agglomeration between lamellas. Besides, the electrical conductivity of the composite material is greatly increased due to good conductivity of the graphene, the hole structure in the composite material can effectively inhibit dissolution of intermediate products in the charging and discharging processes, and the material presents the high specific capacity and good cycling stability. The method has the advantages that operation is easy, cost is low and large-scale production is easy.

Description

technical field [0001] The invention relates to a preparation method of a lithium-sulfur battery cathode material, in particular to a preparation method of a graphene-wound nano-metal oxide / nano-sulfur composite material for a lithium-sulfur battery. Background technique [0002] With the rapid development of electric vehicles and energy storage and other fields, higher and higher requirements are put forward for the battery system. However, due to the limitations of the positive electrode material itself, lithium-ion batteries, which currently dominate the market, are difficult to achieve in terms of energy density. to satisfy the market's needs. Lithium-sulfur battery is a lithium secondary battery with metallic lithium as the negative electrode and elemental sulfur as the positive electrode. It has a theoretical energy density of 2600Wh / kg and an operating voltage of about 2.1V, which can meet the needs of commercialization. Elemental sulfur has abundant sources and is ch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/139
CPCH01M4/139H01M4/362Y02E60/10
Inventor 左朋建张玮尹鸽平高云智
Owner HARBIN INST OF TECH
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