Lithium-sulfur battery composite positive electrode material and preparation method thereof

A composite positive electrode material, lithium-sulfur battery technology, applied in the direction of battery electrodes, circuits, electrical components, etc., to improve cycle performance, reduce energy density loss, and ensure high-efficiency utilization

Inactive Publication Date: 2015-09-09
CHINA UNIV OF GEOSCIENCES (WUHAN)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, maintaining high initial capacity and improving cycle performance at high discharge rates are still not well resolved

Method used

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  • Lithium-sulfur battery composite positive electrode material and preparation method thereof
  • Lithium-sulfur battery composite positive electrode material and preparation method thereof
  • Lithium-sulfur battery composite positive electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Prepare a porous multi-walled carbon nanotube / sulfur / glucose composite positive electrode material with glucose as a modifier, wherein the amount of each component is calculated by mass percentage: conductive agent porous multi-walled carbon nanotube 50wt%, electrochemically active substance sulfur 49.9wt%, modifier glucose 0.1wt%.

[0051] The preparation method of above-mentioned porous multi-wall carbon nanotube is: the potassium hydroxide of solid state and carbon material multi-wall carbon nanotube (aperture is 2-5nm, specific surface area is 324m 2 / g, the pore volume is 0.40cm 3 / g, sold by Nanjing Xianfeng Nano Material Technology Co., Ltd.) uniformly mixed with a mass ratio of 5:1, then placed in a tube furnace, with a mixed gas of hydrogen and nitrogen as a protective atmosphere, wherein the hydrogen volume concentration is 5% , calcined at 850° C. for 1.5 h, then the calcined product was taken out, washed with 1 mol / L dilute hydrochloric acid and then washed...

Embodiment 2

[0059] Prepare a porous multi-walled carbon nanotube / sulfur / glucose composite positive electrode material with glucose as a modifier, wherein the amount of each component is calculated by mass percentage: conductive agent porous multi-walled carbon nanotube 59.4wt%, electrochemical active substance Sulfur 40wt%, modifier glucose 0.6wt%.

[0060] The preparation method of above-mentioned porous multi-wall carbon nanotube is: the potassium hydroxide of solid and multi-wall carbon nanotube (aperture is 2-5nm, specific surface area is 324m 2 / g, the pore volume is 0.40cm 3 / g, sold by Nanjing Xianfeng Nano Material Technology Co., Ltd.) uniformly mixed with a mass ratio of 5:1, then placed in a tube furnace, with a mixed gas of hydrogen and nitrogen as a protective atmosphere, wherein the hydrogen volume concentration is 5% , calcined at 650°C for 1.5h, then the calcined product was taken out, washed with dilute hydrochloric acid and then washed with deionized water until neutral...

Embodiment 3

[0068] Preparation of porous multi-walled carbon nanotubes / sulfur / glucose composite positive electrode material with glucose as a modifier, the method is similar to Example 1, the difference is that the amount of each component is calculated by mass percentage: conductive agent porous multi-walled carbon nano Tube 50wt%, electrochemical active substance sulfur 49.2wt%, modifier glucose 0.8wt%.

[0069] In this example, the preparation of the composite positive electrode material, the preparation of the positive electrode sheet, the method of assembling the battery, and the battery test are all the same as in Example 1. The battery charge and discharge test results show that: under the 1C rate, the first charge and discharge of the battery prepared in this example The specific capacity is 754mAh / g, and the specific capacity after 200 cycles is 561mAh / g. The discharge cycle test diagram of the battery is as follows figure 2 shown. Compared with Example 2, the increase of gluco...

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Abstract

The invention relates to a lithium-sulfur battery composite positive electrode material and a preparation method thereof. The positive electrode material consists of following components by weight percent: 30-59.4% of a conductive agent with a mesoporous structure, 40-60% of sulfur and 0.1-10% of a modifying agent, wherein sulfur is dispersed into holes of the conductive agent, and the modifying agent is connected with the holes of the conductive agent through a chemical bonding manner. The preparation method comprises the steps of pouring sulfur into the conductive agent by adopting a molten suction method so as to obtain a conductive agent/sulfur composite material; and then modifying the obtained conductive agent/sulfur composite material to obtain the lithium-sulfur composite positive electrode material. According to the composite positive electrode material, not only can the good high-rate stability be realized, but also the loss of active substances and the influences of corrosion to a lithium negative electrode, rapid capacity fading and the like caused by the 'shuttle effect' due to dissolution of lithium sulfide can be effectively reduced, and the cycle performance of the lithium-sulfur battery can be obviously improved.

Description

technical field [0001] The invention relates to the technical field of lithium-sulfur batteries, in particular to a lithium-sulfur battery composite cathode material and a preparation method thereof. Background technique [0002] Monosulfur cathode material according to the electrochemical reaction S 8 +16Li→8Li 2 S meter, its specific capacity is as high as 1675mAh·g -1 , has the highest energy density among the known solid cathode materials, and has abundant sulfur single substance reserves, low price, safety and low toxicity, so it has very broad application prospects. But because sulfur is an electronic insulator (5×10 -30 S cm -1 , 25°C), and the high-valence lithium polysulfides formed during the discharge process (when the lithium-sulfur battery is at different discharge voltages, lithium and sulfur react to form lithium polysulfides with different valence states of sulfur, and the specific products are from high-valence states to low-valence states. The valence ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/62
CPCH01M4/624H01M4/625H01M4/62Y02E60/10
Inventor 周成冈周吟闫允璠韩波吴金平
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)
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