Positive electrode for lithium sulfur battery

A lithium-sulfur battery and positive electrode technology, applied in the field of lithium-sulfur batteries, can solve the problems of poor electrode reversibility and high rate performance, reduce the utilization rate of active materials, battery cycle capacity attenuation, etc., achieve simple and feasible preparation process, improve cycle stability performance, the effect of reducing the self-discharge phenomenon

Active Publication Date: 2015-01-21
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Abstract
  • Description
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AI Technical Summary

Problems solved by technology

The above shuttle effect always exists during the operation of the battery, which is manifested by reducing the utilization rate of the active material during the discharge process and reducing the Coulombic efficiency during the charge process.
3) The battery cycle capacity decays seriously
The main reason is that the insulating insoluble Li, which is completely separated from the electronic conductor, is gradually deposited on the positive side. 2 S / Li 2 S 2 Agglomeration, resulting in loss of active substance sulfur
In addition, the stress caused by the huge volume change of the positive and negative electrode materials will also lead to the destruction of the electrode structure.
4) Poor electrode reversibility and high rate performance
In contrast, these measures can only improve the cycle stability to a certain extent, but cannot fundamentally solve the cycle stability of lithium-sulfur batteries. Therefore, it is necessary to develop new methods to improve the cycle stability of lithium-sulfur batteries.

Method used

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  • Positive electrode for lithium sulfur battery
  • Positive electrode for lithium sulfur battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040]Take 1g of sulfur mass content 10% sulfur / activated carbon (cathode material) and add it to 100ml ethylene glycol solution, stir and sonicate for 1h, mix well to form solution A, add 6.67ml chloroauric acid solution (1.5mgAu / ml ), stirred and ultrasonicated for 10 hours, mixed evenly to form solution B, added dropwise 0.5mol / L ethylene glycol sodium hydroxide solution to solution B, adjusted the pH to 9, stirred for 10 minutes, and formed solution C; microwaved solution C for 1 minute , cooled to room temperature to form solution D; add 4mol / L ethylene glycol hydrochloric acid solution to solution D, adjust the pH value to 1, stir for 1h, let stand overnight, form powder E after suction filtration and washing, and mix powder E with acetylene Black and PVDF are ultrasonically mixed in N,N-dimethylformamide (NMP) solution according to the mass ratio of 8:1:1, and then scraped onto the aluminum foil to obtain the positive electrode of the lithium-sulfur battery. The battery ...

Embodiment 2

[0042] Take 1g of sulfur / graphene with a mass content of 95% sulfur (positive grade material) and add it to 500ml of ethylene glycol solution, stir and sonicate for 5h, mix evenly to form solution A, and add chloroauric acid solution containing 1g of Au to solution A , stir and ultrasonic for 1 hour, mix well to form solution B, add 0.5mol / L ethylene glycol sodium carbonate solution dropwise to solution B, adjust the pH value to 12, stir for 120 minutes, and form solution C; microwave solution C for 3 minutes, cool to room temperature to form solution D; add 4mol / L ethylene glycol sulfuric acid solution to solution D, adjust the pH value to 0.9, stir for 6h, let it stand overnight, form powder E after suction filtration and washing, mix powder E with acetylene black, PVDF is ultrasonically mixed in N,N-dimethylformamide (NMP) solution according to the mass ratio of 8:1:1, and then scraped onto the aluminum foil to obtain the positive electrode of lithium-sulfur battery. The bat...

Embodiment 3

[0044] Take 1g of sulfur / carbon nanotubes (positive material) with a sulfur mass content of 70% and add it to 300ml of ethylene glycol solution, stir and sonicate for 3h, mix well to form solution A, and add gold chloride containing 0.0526g of Au to solution A Acid solution, stirred and ultrasonicated for 3 hours, mixed evenly to form solution B, added dropwise 0.5mol / L sodium carbonate solution of ethylene glycol to solution B, adjusted the pH value to 11, stirred for 120min, formed solution C; refluxed and heated solution C Keep at 140°C for 4 hours, cool to room temperature to form solution D; add 4mol / L ethylene glycol sulfuric acid solution to solution D, adjust the pH value to 0.9, stir for 6 hours, stand overnight, and form powder E after suction filtration and washing , Mix powder E, acetylene black, and PVDF in N,N-dimethylformamide (NMP) solution with a mass ratio of 8:1:1, and then apply it on an aluminum foil to obtain a positive electrode for a lithium-sulfur batte...

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Abstract

The invention relates to a positive electrode for a lithium sulfur battery. The material of the positive electrode is a one or two or above two of a carbon-sulfur composite material, a sulfur-conductive polymer composite material and a sulfur-metal oxide composite material, and the content of sulfur in the positive electrode material is 10-95%; the positive electrode material also contains nano-gold or/and nano-silver particles; and a ratio of the total addition of the nano-gold or/and silver to the mass of the positive electrode material is 1:(0.01-1). The electronic orbital effect of the nano-gold or/and silver is used to complex polysulfide in order to make products in the discharge process maximally fixed in a positive electrode region, so the self discharge phenomenon caused by the dissolution of the polysulfide is effectively inhibited, thereby the coulomb efficiency and the cycle stability of the lithium sulfur battery are improved.

Description

technical field [0001] The invention relates to a lithium-sulfur battery, in particular to a positive-stage material for the lithium-sulfur battery. Background technique [0002] Lithium-sulfur battery is a secondary battery with metal lithium as the negative electrode and elemental sulfur as the positive electrode. Its specific energy can theoretically reach 2600Wh / kg, and the actual energy density can reach 300Wh / kg at present, and it is very likely to increase to 300Wh / kg in the next few years. At the same time, the elemental sulfur cathode material has the advantages of abundant sources, low price, and environmental friendliness, and is considered to be one of the most attractive secondary battery systems at present. [0003] However, after nearly 30 years of research, except for the application demonstrations of a few companies in the high-end field in recent years, lithium-sulfur batteries are still not commercially available. This is because some serious defects inhe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/62
CPCH01M4/139H01M4/362H01M4/62H01M4/626Y02E60/10
Inventor 王美日张华民张益宁张凤祥曲超王倩马艺文
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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