Preparation method and application of lithium-sulfur battery positive electrode material

A technology for lithium-sulfur batteries and cathode materials, which is applied in the field of material science and can solve the problems of low electrical conductivity, low cycle performance of lithium-sulfur batteries, and complicated charging and discharging processes.

Active Publication Date: 2022-03-18
BEIJING INFORMATION SCI & TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, the electronic and ionic conductivity of elemental sulfur is very poor, and the conductivity of sulfur materials at room temperature is extremely low (5.0×10 -30 S cm -1 ), the final product of the reaction Li 2 S 2 and Li 2 S is also an electronic insulator, which is not conducive to the high rate performance of the battery; the charging and discharging process of lithium-sulfur batteries is complicated, and there are many intermediate products. and the final product Li 2 The density of S is different. When sulfur is lithiated, the volume expands by about 79%, which easily leads to Li 2 Pulverization of S, causing safety problems in lithium-sulfur batteries
The three problems mentioned above restrict the development of lithium-sulfur batteries

Method used

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  • Preparation method and application of lithium-sulfur battery positive electrode material
  • Preparation method and application of lithium-sulfur battery positive electrode material
  • Preparation method and application of lithium-sulfur battery positive electrode material

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Effect test

Embodiment 1

[0037] (1) Mix black phosphorus powder and magnesium boride powder in a mass ratio of 2:3, put them in a beaker and mix for 24 hours.

[0038] (2) Put it into a crucible after drying, and use a muffle furnace to perform high-temperature calcination at 620°C with a heating rate of 10°C / min and a holding time of 24h.

[0039] (3) Take out the calcined product, wash the product centrifugally with deionized water, and then dry it at 60° C. to obtain black phosphorus@magnesia quantum dots.

[0040] (4) Mix and grind the black phosphorus@magnesia quantum dots obtained by drying with elemental sulfur powder in a mass ratio of 1:3 for 15 minutes, and mix the obtained product with carbon disulfide in a mass ratio of 1:5, and continue grinding until The carbon disulfide is completely evaporated to obtain a uniformly mixed product, which is then collected in a sealed weighing bottle, and finally placed in an oven at 155°C for 10 hours. Finally, samples of black phosphorus@magnesia quant...

Embodiment 2

[0045] (1) Mix black phosphorus powder and magnesium boride powder at a mass ratio of 1:1, put them into a beaker, add deionized water and stir for 24 hours.

[0046] (2) Put it into a crucible after drying, and use a muffle furnace to perform high-temperature calcination at 570° C., the heating rate is 10° C. / min, and the holding time is set to 24 hours.

[0047] (4) Take out the calcined product, wash the product centrifugally with deionized water, and then dry it at 60° C. to obtain the black phosphorus / magnesia quantum dots.

[0048](5) Mix and grind the black phosphorus@magnesia quantum dots obtained by drying with the elemental sulfur powder in a mass ratio of 1:3 for 15 minutes, and mix the obtained product with carbon disulfide in a mass ratio of 1:5, and continue grinding until The carbon disulfide is completely evaporated to obtain a uniformly mixed product, which is then collected in a sealed weighing bottle, and finally placed in an oven at 150°C for 12 hours. Fin...

Embodiment 3

[0050] (1) Mix black phosphorus powder and magnesium boride powder at a mass ratio of 1:7, put them into a beaker, add deionized water and stir for 24 hours.

[0051] (2) Put it into a crucible after drying, and use a muffle furnace to perform high-temperature calcination at 720°C with a heating rate of 10°C / min and a holding time of 1h.

[0052] (4) Take out the calcined product, wash the product centrifugally with deionized water, and then dry it at 60° C. to obtain black phosphorus@magnesia quantum dots.

[0053] (5) The black phosphorus / magnesia quantum dots obtained by drying are mixed and ground for 15 minutes with the elemental sulfur powder in a ratio of 1:3 by mass, and the product obtained is mixed with carbon disulfide in a ratio of 1:5 by mass, and then continue to grind until The carbon disulfide evaporates completely to obtain a uniformly mixed product, which is then collected in a sealed weighing bottle, and finally placed in an oven at 160°C for 4 hours. Final...

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Abstract

The invention discloses a preparation method of a positive electrode material of a lithium-sulfur battery. The preparation method comprises the following steps: obtaining BP (at) MQD by using an in-situ vapor deposition method; and compounding elemental sulfur with the BP (at) MQD. The preparation method comprises the following steps: fully mixing red phosphorus powder and magnesium boride powder according to a certain proportion by using a beaker, and sintering in a muffle furnace; and removing non-fixed-state boron oxide in the product by a centrifugal washing method to obtain the required host material. The magnesium oxide quantum dots in the host material have strong polarity and can capture long-chain polysulfide and reduce the shuttle effect; the BP (at) MQD heterojunction can improve the electron transfer rate and accelerate the reaction kinetics. According to the invention, elemental sulfur is used as a positive electrode active material, BP-coated MQD is used as a host material of sulfur, and compared with other lithium-sulfur battery positive electrode materials, the cycle stability and rate capability of the battery are optimized. The preparation method is simple in process, low in equipment requirement, excellent in performance and suitable for large-scale commercial battery production.

Description

technical field [0001] The invention relates to the technical field of material science, and more specifically relates to a preparation method and application of a lithium-sulfur battery cathode material. Background technique [0002] The reaction mechanism of a typical lithium-sulfur battery is an electrochemical mechanism. Sulfur and lithium in the positive and negative electrodes react to form sulfide through the gain and loss of electrons. The potential difference formed after the reaction between the positive and negative electrodes is the discharge voltage. When the voltage is applied, the positive and negative reactions are reversed, which is the charging process. Sulfur is used as the positive electrode active material, mainly S 8 Existing in the form of carbon dioxide, it is abundant in the earth, and has the characteristics of low price and environmental friendliness. According to the unit mass of elemental sulfur is completely changed into S 2- It can be obtain...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/58H01M10/052
CPCH01M4/362H01M4/38H01M4/58H01M10/052H01M2004/028Y02E60/10
Inventor 廖擎玮侯薇廖柯璇秦雷
Owner BEIJING INFORMATION SCI & TECH UNIV
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