Titanium dioxide-coated lithium-sulfur battery positive electrode material and preparation method thereof

A cathode material, titanium dioxide technology, applied in the preparation of cathode materials for lithium-sulfur batteries, in the field of cathode materials for lithium-sulfur batteries coated with titanium dioxide, can solve the problems of irreversible loss of positive active materials, low electronic conductivity, and reduced battery capacity, etc., to achieve Effects of reduced shuttle effect, discharge specific capacity, and improved cycle stability

Active Publication Date: 2018-01-12
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above method is simple, there are mainly the following problems: elemental sulfur is an electronic and ion insulator at room temperature, has extremely low electronic conductivity, and the polysulfides produced during the charging and discharging process of the battery are easily soluble in the electrolyte, resulting in " Shuttle effect”, resulting in a large amount of irreversible loss of positive active material, reducing the capacity of the battery
However, TiO 2 There are some problems in the conductivity, resulting in a certain bottleneck in the improvement of battery performance
In summary, although the above methods can improve the electrochemical performance of lithium-sulfur batteries to a certain extent, their electrochemical performance such as specific discharge capacity and cycle stability is still far from commercialization and needs to be improved.

Method used

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  • Titanium dioxide-coated lithium-sulfur battery positive electrode material and preparation method thereof
  • Titanium dioxide-coated lithium-sulfur battery positive electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Take the sublimated sulfur of the size of carbon fiber cloth of the positive electrode material and put it in a graphite crucible, cover it with a layer of carbon fiber cloth, and compact it with a heavy object. Put it in a tube furnace, heat the crucible to 155°C in a nitrogen atmosphere, and keep it warm for 6 hours to sublimate the sulfur. Under the adsorption of the micropores on the carbon fiber cloth, the sulfur is attached to the carbon fiber cloth, and a carbon fiber cloth with good S coating is obtained.

[0023] 98% TiCl 4 The solution was diluted to a 5% ethanol solution, and further diluted to a 2% dilute solution with a mass fraction of water.

[0024] The prepared sulfur-containing carbon fiber cloth was made into the size of a battery pole piece and placed in 2% TiCl 4 After 0.5h in the aqueous solution, take it out, wash and dry, and obtain a titanium dioxide-coated lithium-sulfur battery positive electrode material. The battery is then assembled and t...

Embodiment 2

[0026] Take the sublimated sulfur of the size of carbon fiber cloth of the positive electrode material and put it in a graphite crucible, cover it with a layer of carbon fiber cloth, and compact it with a heavy object. Put it in a tube furnace, heat the crucible to 155°C in a nitrogen atmosphere, and keep it warm for 7 hours to sublimate the sulfur. Under the adsorption of the micropores on the carbon fiber cloth, the sulfur is attached to the carbon fiber cloth, and a carbon fiber cloth with good S coating is obtained.

[0027] 98% TiCl 4 The solution was diluted to a 5% mass fraction of an ice-water solution, and further diluted with water to a 2% mass fraction of a dilute solution.

[0028] The prepared sulfur-containing carbon fiber cloth was made into the size of a battery pole piece and placed in 2% TiCl 4 In the aqueous solution, take it out after 3 hours, wash and dry, and obtain the titanium dioxide-coated lithium-sulfur battery positive electrode material. The batt...

Embodiment 3

[0030]Take the sublimated sulfur of the size of carbon fiber cloth of the positive electrode material and put it in a graphite crucible, cover it with a layer of carbon fiber cloth, and compact it with a heavy object. Put it in a tube furnace, heat the crucible to 155°C in a nitrogen atmosphere, and keep it warm for 9 hours to sublimate the sulfur. Under the adsorption of the micropores on the carbon fiber cloth, the sulfur is attached to the carbon fiber cloth, and a carbon fiber cloth with good S coating is obtained.

[0031] Keep the temperature at 0℃~10℃ under the condition of ice water bath, add ice water to dilute 98% TiCl 4 solution to a solution with a mass fraction of 50%.

[0032] The carbon fiber cloth after absorbing sulfur was put into the solution, vigorously stirred for 10 minutes, washed and dried, and a titanium dioxide-coated lithium-sulfur battery positive electrode material was obtained. The battery is then assembled and tested. Scanning electron microsco...

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Abstract

The invention discloses a titanium dioxide-coated lithium sulphur battery anode material and a preparation method thereof, used for solving the technical problem that an existing lithium sulphur battery anode material is low in specific discharge capacity. The technical scheme is that the anode material is prepared from sulphur, a carbon fiber sheet and a titanium dioxide casing. The preparation method comprises the steps of adsorbing a gas sulfur elementary substance by adopting the carbon fiber sheet, then using titanium dioxide to coat a mixture of the carbon fiber sheet and the sulfur elementary substance by adopting a titanium tetrachloride hydrolysis method, drying, cleaning, and drying again to obtain the titanium dioxide-coated lithium sulphur battery anode material. As elementary substance sulfur particles evenly cover the surface of the carbon fiber sheet and are externally coated by TiO2 evenly, the strong adsorption fixing capacity of the microcosmic structure of the carbon fiber sheet and the TiO2 to a polysulfide buffers volume change before and after sulfur lithiation and can limit the polysulfide generated in the charging and discharging processes of a lithium sulphur battery in a TiO2 nanotube, so that the specific discharge capacity and the cycling stability of the lithium sulphur battery are remarkably improved.

Description

technical field [0001] The invention relates to a lithium-sulfur battery cathode material, in particular to a titanium dioxide-coated lithium-sulfur battery cathode material. It also relates to a preparation method of the titanium dioxide-coated lithium-sulfur battery cathode material. Background technique [0002] Among many secondary batteries, traditional lithium-sulfur secondary batteries use metal lithium (theoretical specific capacity 3861mAh g -1 ) as the negative electrode, elemental sulfur (theoretical specific capacity 1675mAh g -1 ) as the positive electrode, the theoretical energy density is as high as 2600Wh·kg -1 , is currently known as the lithium secondary battery system with the highest energy density except for lithium-air batteries; at the same time, lithium-sulfur batteries also have the advantages of abundant sulfur cathode materials, low cost and environmental friendliness, and are considered to be the most developed at present. One of the secondary ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/052H01M4/13H01M4/139H01M4/583H01M4/48
CPCH01M4/13H01M4/139H01M4/362H01M4/366H01M4/483H01M4/583H01M10/052Y02E60/10
Inventor 谢科予张坤韩昀钊原凯王建淦魏秉庆
Owner NORTHWESTERN POLYTECHNICAL UNIV
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