A preparation method of lithium sulfide battery cathode material

Abstract

The invention relates to a preparation method of a lithium sulfur battery cathode material. This method uses N,N-Dimethylformamide (DMF) is use as a solvent, In-situ polyacrylonitrile (PAN) / graphene oxide (GO) was dissolved in DMF to prepare spinning precursor, Continuous nanofiber membranes were prepared by electrospinning, In-situ nitrogen doped carbon fiber / reduced graphene oxide composite wasprepared by carbonization of electrospun PAN / GO fiber, At last, the nitrogen-doped carbon fiber / reduced graphene oxide / sulfur composite cathode material is prepare by the sulfur doping process, This kind of composite material with excellent conductivity and adsorption ability for polysulfide can not only make up the disadvantage of poor conductivity of elemental sulfur but also play a role of sulfur fixation and improve the shuttle effect of polysulfide in the reaction process so as to improve the electrochemical performance of lithium sulfide batteries.

Description

technical field

[0001] The invention relates to a preparation method of a lithium-sulfur battery cathode material, in particular to an in-situ nitrogen-doped carbon fiber / reduced graphene oxide composite material prepared by electrospinning technology, and belongs to the field of material chemistry. Background technique

[0002] With the increasing development of society, people have higher requirements for energy efficiency, portability and safety. The theoretical specific capacity of lithium-sulfur batteries is as high as 1672mAh / g (theoretical energy density can reach 2600Wh / kg), which is several times the specific capacity of existing lithium-ion cathode materials, and elemental sulfur has the advantages of abundant resources, low price and environmental friendliness, and has become a A new lithium-ion battery that has attracted much attention. However, the low conductivity of elemental sulfur and the shuttling effect of soluble polysulfides during charge and discharge ...

Examples

Embodiment 1

[0040] Step 1, improving the Hummers method to prepare graphene oxide:

[0041] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0042] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0043] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

Embodiment 2

[0058] Step 1, improving the Hummers method to prepare graphene oxide:

[0059] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0060] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0061] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

Embodiment 3

[0075] Step 1, improving the Hummers method to prepare graphene oxide:

[0076] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0077] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0078] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

technical field

[0001] The invention relates to a preparation method of a lithium-sulfur battery cathode material, in particular to an in-situ nitrogen-doped carbon fiber / reduced graphene oxide composite material prepared by electrospinning technology, and belongs to the field of material chemistry. Background technique

[0002] With the increasing development of society, people have higher requirements for energy efficiency, portability and safety. The theoretical specific capacity of lithium-sulfur batteries is as high as 1672mAh / g (theoretical energy density can reach 2600Wh / kg), which is several times the specific capacity of existing lithium-ion cathode materials, and elemental sulfur has the advantages of abundant resources, low price and environmental friendliness, and has become a A new lithium-ion battery that has attracted much attention. However, the low conductivity of elemental sulfur and the shuttling effect of soluble polysulfides during charge and discharge ...

Examples

Embodiment 1

[0040] Step 1, improving the Hummers method to prepare graphene oxide:

[0041] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0042] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0043] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

Embodiment 2

[0058] Step 1, improving the Hummers method to prepare graphene oxide:

[0059] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0060] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0061] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

Embodiment 3

[0075] Step 1, improving the Hummers method to prepare graphene oxide:

[0076] 1g of graphite, 27ml of 95% H 2 SO 4 , 3ml concentration of 0.1M H 3 PO 4 Place in a three-necked flask, and add 6g of potassium permanganate in portions, stir in an ice-water bath for 1h, raise the temperature to 50°C, and keep the reaction for 12h. The resulting product was poured into ice water, and 30% hydrogen peroxide was added while stirring until the color of the solution turned golden yellow, then filtered, and the product was washed with 5% HCL and distilled water until the pH value was close to 7. The obtained graphite oxide is dispersed in water, ultrasonicated for 8 hours, and finally configured as a 2 mg / ml graphene oxide solution for later use;

[0077] Step 2: In situ polymerization of acrylonitrile / graphene oxide composites

[0078] PAN / GO composites were prepared by in situ polymerization. First, 125ml of deionized water, 12.5ml of acrylonitrile and 50ml of GO solution with ...

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