Preparation method of S-C positive pole composite material of high cycle performance lithium sulfur battery

A technology of cycle performance and composite materials, applied in the field of electrochemical cells, can solve the problems of complex nano-carbon production method, long sulfur-carbon composite time, poor cycle performance, etc., and reduce self-discharge and polysulfide ion shuttle effect. , The effect of high product performance consistency and small change in sulfur content

Inactive Publication Date: 2014-02-05
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above method, using various nano-carbons and elemental sulfur for fusion method, improves the discharge capacity of the first dozens of times to a certain extent, but the overall cycle performance is still not good, and the nano-carbon production method is complicated and expensive. The sulfur-carbon recombination time is long (≥8h), so there is still a long way to go before the practical use of lithium-sulfur batteries, and continuous improvement is needed

Method used

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  • Preparation method of S-C positive pole composite material of high cycle performance lithium sulfur battery
  • Preparation method of S-C positive pole composite material of high cycle performance lithium sulfur battery
  • Preparation method of S-C positive pole composite material of high cycle performance lithium sulfur battery

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Experimental program
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Effect test

Embodiment 1

[0024] Weigh 1.4g of sublimed sulfur and 0.6g of Ketjen black conductive carbon black, put them in a ball milling tank, add agate balls, and ball mill on a ball mill at a speed of 250r / min for 10 hours to obtain a uniformly mixed S-C composite powder. Then put the ball-milled SC composite powder on the rotating table of the microwave oven, evacuated and vented with nitrogen gas, controlled the rotating table speed to be 4.5r / min, the heating rate to 18℃ / min, and keep it at 149℃ for 120s, microwave The output power is 2.4kW, and the SC microwave composite material with a sulfur content of 55.53wt% is obtained. Using N-methylpyrrolidone as the organic solvent, the prepared S-C microwave composite material, acetylene black and PVDF were slurried at a mass ratio of 7:1:2. Finally, the adjusted slurry was evenly coated on the aluminum sheet and placed in a vacuum drying oven at 60°C for 12 hours. figure 1 It is the XRD pattern of the obtained sample. It can be seen from the figure t...

Embodiment 2

[0026] Weigh 1.6 g of sublimed sulfur and 0.4 g of acetylene black, put them in a ball mill tank, add agate balls, and ball mill on a ball mill at a speed of 300 r / min for 8 hours to obtain a uniformly mixed S-C composite powder. Then put the ball-milled SC composite powder on the rotating table of the microwave oven, evacuated and ventilate argon gas, control the rotating table speed to 4r / min, the heating rate to 15℃ / min, heat preservation at 125℃ for 150s, microwave The output power is 2.0kW, and the SC microwave composite material with a sulfur content of 59.26wt% is obtained. Figure 4 It is the XRD pattern of the obtained sample, which can be seen from the figure, and also shows the existence of crystalline and amorphous sulfur without any impurity phase. Using deionized water as the solvent, the prepared S-C microwave composite material, Ketjen black conductive carbon black, and LA133 were slurried at a mass ratio of 7:2:1. Finally, the adjusted slurry was evenly coated...

Embodiment 3

[0028] Weigh 1.2g of sublimed sulfur and 0.8g of BP2000 conductive carbon black, put them in a ball milling tank, add agate balls, and ball mill on a ball mill at a speed of 400r / min for 5 hours to obtain a uniformly mixed S-C composite powder. Then place the ball-milled SC composite powder on the rotating table of the microwave oven, evacuated and blow in nitrogen gas, control the rotating table speed to 5r / min, heating rate to 25℃ / min, heat preservation at 170℃ for 90s, microwave output power It is 2.8kW, and the SC microwave composite material with a sulfur content of 48.11wt% is obtained. Using acetone as the organic solvent, the prepared S-C microwave composite material, BP2000 conductive carbon black and PVDF were slurried at a mass ratio of 7:1.5:1.5. Finally, the adjusted slurry was evenly coated on the aluminum sheet and placed in a vacuum drying oven at 65°C for 10 hours. Using this material as the positive electrode and the metal lithium sheet as the negative electr...

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Abstract

The invention relates to a preparation method of an S-C positive pole microwave composite material of a high cycle performance lithium sulfur battery. Firstly, sulfur, carbon materials are put into a ball mill for ball-milling mixing, and then put into a microwave oven for microwave heating and compositing to prepare the S-C positive pole microwave composite material with high dispersion uniformity. The S-C positive pole microwave composite material and a conductive agent are ground and mixed uniformly, the S-C positive pole microwave composite material and a binder are dispersed in an organic solvent in a certain proportion, and stirred to prepare paste, and then the paste is evenly coated onto a current collector sheet, and dried to prepare a positive pole. The preparation method adopts an advanced microwave heating method, has the advantages of fast heating speed, mild conditions and high efficiency, the prepared positive pole composite material is stable in structure, the battery has good cycle stability, at the same time, the commercial carbon material with low price is used, the material cost is greatly reduced, and the preparation method is suitable for popularization.

Description

Technical field [0001] The invention belongs to the field of electrochemical batteries, and particularly relates to a method for preparing a lithium-sulfur battery S-C positive electrode composite material with high cycle performance. Background technique [0002] The theoretical specific capacity of elemental sulfur is 1675mAh / g. It forms a lithium-sulfur battery with metal lithium. The theoretical specific energy is 2600Wh / kg, which is much higher than LiCoO, a common cathode material for lithium-ion batteries. 2 , LiMnO 2 , LiFePO 4 Capacity. In addition, elemental sulfur is cheap and easy to obtain, environmentally friendly and other advantages also make it worthy of large-scale applications. [0003] However, limited by the insulating properties of sulfur and its discharge product, lithium sulfide, and a series of lithium polysulfide intermediate products formed during charging and discharging are easily soluble in the electrolyte, lithium-sulfur batteries have low utilization...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62
CPCH01M4/366H01M4/38H01M4/625Y02E60/10
Inventor 杨晖许寒雪王卓王宁
Owner NANJING UNIV OF TECH
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