Sulfur-porous carbon felt composite positive material for lithium battery

A technology of composite positive electrode material and carbon felt, which is applied to battery electrodes, lithium storage batteries, non-aqueous electrolyte storage batteries, etc., can solve the problems of loss of cycle performance of active materials, complicated preparation methods, and high cost, and achieves maintenance of cycle performance and simple preparation methods. , to achieve the effect of mass production

Inactive Publication Date: 2014-08-20
XUZHOU NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These soluble polysulfides are then diffused and transported to the lithium negative electrode to form lithium low-order polysulfides, and then diffuse back to the sulfur positive electrode, thereby causing corrosion of the lithium negative electrode, destroying the cycle performance of the battery system, and causing active material degradation. loss
The occurrence of this "shuttle effect (shuttle)" seriously restricts the cycle performance of sulfur electrodes and the development of practical battery systems.
The third is that Li2S2/Li2S with poor conductivity and electrochemical reversibility is formed during the complete ...

Method used

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  • Sulfur-porous carbon felt composite positive material for lithium battery
  • Sulfur-porous carbon felt composite positive material for lithium battery
  • Sulfur-porous carbon felt composite positive material for lithium battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Weigh 5g of sulfur powder into a 100mL zirconia ball mill jar, then add 20mL of ethanol (>99.7%, analytically pure), and mill at 500 rpm for 2 hours; then drop the obtained sulfur-containing slurry onto 5g of activated carbon felt ( Produced by Qingdao Huashijie Environmental Protection Technology Co., Ltd., 30mg / cm 2 ), vacuum drying at 58oC for 14h; the obtained composite felt was compacted, and then heat-treated in a muffle furnace at 152oC for 14h to obtain a sulfur-activated carbon felt composite cathode material (prepared by infiltration and heat treatment), with a sulfur content of 48.6%.

[0026] Such as figure 1 As shown, there is no obvious change in its XRD spectrum before and after compounding with sulfur.

[0027] Such as figure 2 As shown, before and after compounding with sulfur, the overall morphology has no obvious change, and it is a conductive carbon network formed by the cross-linking of activated carbon fibers, but there is obvious sulfur on the ...

Embodiment 2

[0029] The sulfur-activated carbon felt composite cathode material obtained above is punched into 50mm 2 The disc is the positive electrode, and the sulfur loading is 14.2mg. Lithium metal is the negative electrode, and the electrolyte is 1mol / L LiN(CF 3 SO 2 ) 2 solution (0.2mol / L lithium nitrate), the solvent is a mixture of dioxolane and dimethoxyethane in a volume ratio of 1:1. Assemble the battery in the glove box.

[0030] The charge and discharge research of the installed battery is carried out at room temperature, and the charge and discharge voltage range is: 1.7V~2.8V. Such as image 3 As shown, at a current density of 80mA / g (calculated according to sulfur), its reversible charge capacity is 4.48mAh, and its surface capacity reaches 8.96mAh / cm 2 .

Embodiment 3

[0032] Weigh 15g of elemental sulfur and dissolve it in 50mL of carbon disulfide solution, and then apply 3g of activated carbon felt (Qingdao Huashijie Environmental Protection Technology Co., Ltd., 10mg / cm 2 ) into the prepared carbon disulfide solution of sulfur and soaked for 6 hours, took it out and placed it in a fume hood for 14 hours, and then dried it in vacuum at 58oC for 15 hours to obtain the sulfur-activated carbon felt composite positive electrode material (prepared by solution infiltration and infiltration method), containing sulfur The amount is 38.9%. .

[0033] The sulfur-activated carbon felt composite cathode material obtained above is punched into 50mm 2 The disc is the positive electrode, and the weight of the entire pole piece is 8mg. Lithium metal is the negative electrode, and the electrolyte is 1mol / L LiN(CF 3 SO 2 ) 2 solution (0.2mol / L lithium nitrate), the solvent is a mixture of dioxolane and dimethoxyethane in a volume ratio of 1:1. Assembl...

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Abstract

The invention relates to a sulfur-porous carbon felt composite positive material for a lithium battery. The composite positive material is a sulfur-porous carbon felt composite positive material which is obtained by compounding sulfur and a porous carbon felt. The porous carbon felt is active carbon felt or mesoporous carbon felt, and the sulfur content is 30 to 70 percent. The dissolving of polysulfide is limited by utilizing the porous structure of the carbon felt; in addition, different from the traditional porous carbon material, the carbon felt can partially or completely substitute adhesive and acetylene black, additional adhesive and acetylene black are not needed, the overall energy intensity of the electrode material can be effectively improved, when the composite electrode material is applied to a secondary lithium-sulfur battery, the discharging performance is good, and the surface capacity is high. Due to the characteristics of the structure, the carbon felt can be directly applied to a soft-packaging battery; and different from the traditional sulfur electrode which needs a pulping coating step, the practical prospect of the sulfur-porous carbon felt composite positive material is promising.

Description

technical field [0001] The invention relates to a sulfur-porous carbon felt composite positive electrode material for lithium batteries. Background technique [0002] In theory, Li2S is formed after complete reaction of lithium and sulfur, which can realize 2-electron reaction, and the atomic weight of elemental sulfur is significantly lighter than that of the current commercial lithium-ion battery intercalation compound cathode material, which is the most potential high-capacity electrode material. The theoretical specific capacity of the electrode can be as high as 1675mAh / g, the theoretical energy density of the lithium / sulfur secondary battery system constructed of sulfur and lithium metal can reach 2600Wh / kg, and the positive electrode material cobalt of lithium ion batteries that has been commercialized or studied more Lithium oxide, spinel-type lithium manganate, lithium-nickel-cobalt-manganese units or multi-layered oxides, olivine-type lithium iron phosphate, lithiu...

Claims

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Application Information

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IPC IPC(8): H01M4/36H01M4/62
CPCH01M4/362H01M4/623H01M4/625H01M10/052Y02E60/10
Inventor 赖超杨东江郗凯
Owner XUZHOU NORMAL UNIVERSITY
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