Nitrogen-containing binder for sulfur-lithium batteries and preparation method thereof

Abstract

The invention relates to a nitrogen-containing binder for sulfur-lithium batteries and a preparation method thereof. The binder is a nitrogen-containing cyclodextrin polymer water-based binder with a three-dimensional network structure. The existing three-dimensional network structure can well bear the mechanical pressure brought by sulfur-lithium batteries in the charging and discharging process due to volume change, introduced nitrogen-containing functional groups can effectively inhibit the problems of dissolution and shuttle effect of polysulfide ions in electrolyte, a number of hydroxyl groups exist in the cyclodextrin and have strong hydrogen-bond interaction with anode material particles, and the stability of pole pieces can be maintained. In addition, the binder also has a role of increasing guide ions. Therefore, the binder can effectively solve the problem that a positive polysulfide material in the sulfur-lithium batteries is unstable in organization structure, the utilization rate of composite material active matter and the rate capability of the active matter can be improved, and accordingly the specific power, specific energy and cyclicity of the batteries can be improved.

Description

technical field

[0001] The invention relates to a nitrogen-containing binder for lithium-sulfur batteries and a preparation method thereof, belonging to the field of chemical power sources. Background technique

[0002] The secondary lithium-sulfur battery with elemental sulfur as the positive electrode has a high theoretical specific capacity of 1675mAh / g, and elemental sulfur is cheap, abundant in resources, and environmentally friendly. Therefore, lithium-sulfur batteries are considered to be the most promising new generation of high-energy batteries. One of the chemical power sources of Biener. However, due to the poor conductivity of elemental sulfur and the volume expansion during charging and discharging, the polysulfide ions generated during the discharging process will dissolve, diffuse and migrate, which restricts the further development and application of lithium-sulfur batteries.

[0003] To address these problems in lithium-sulfur batteries, researchers from va...

Examples

Embodiment 1

[0041] Add 25g of β-cyclodextrin, 50ml of water, and 15g of sodium hydroxide into the reaction flask, stir vigorously at room temperature for 4 hours, add 20.35g of epichlorohydrin, continue stirring for 4 hours at room temperature, add acetone to stop the reaction, chromatograph, and neutralize with hydrochloric acid , dialyzed, and concentrated to obtain the β-cyclodextrin polymer.

Embodiment 2

[0043] Weigh 15g of the product of Example 1 into a reaction flask, add 15g of sodium hydroxide, 65ml of N,N-dimethylformamide (DMF), stir at 20°C for 30min, add 4.04g of 4-methyl-benzene dissolved in The solution of sulfonyl chloride in 15ml DMF was stirred at 20°C for 3h, neutralized with HCl, dialyzed, concentrated, and freeze-dried to obtain p-toluenesulfonylated β-cyclodextrin polymer.

Embodiment 3

[0045] Dissolve 5 g of the dried product in Example 2 in 100 ml of N, N-dimethylformamide (DMF), add anhydrous 3 g of NaI, and react for 5 hours under magnetic stirring at 90 ° C. After cooling, rotary evaporation removes the solvent. Wash with acetone to remove excess NaI, dissolve the precipitate in a small amount of water, filter, and wash the filtrate with acetone to obtain a white powder.

technical field

[0001] The invention relates to a nitrogen-containing binder for lithium-sulfur batteries and a preparation method thereof, belonging to the field of chemical power sources. Background technique

[0002] The secondary lithium-sulfur battery with elemental sulfur as the positive electrode has a high theoretical specific capacity of 1675mAh / g, and elemental sulfur is cheap, abundant in resources, and environmentally friendly. Therefore, lithium-sulfur batteries are considered to be the most promising new generation of high-energy batteries. One of the chemical power sources of Biener. However, due to the poor conductivity of elemental sulfur and the volume expansion during charging and discharging, the polysulfide ions generated during the discharging process will dissolve, diffuse and migrate, which restricts the further development and application of lithium-sulfur batteries.

[0003] To address these problems in lithium-sulfur batteries, researchers from va...

Examples

Embodiment 1

[0041] Add 25g of β-cyclodextrin, 50ml of water, and 15g of sodium hydroxide into the reaction flask, stir vigorously at room temperature for 4 hours, add 20.35g of epichlorohydrin, continue stirring for 4 hours at room temperature, add acetone to stop the reaction, chromatograph, and neutralize with hydrochloric acid , dialyzed, and concentrated to obtain the β-cyclodextrin polymer.

Embodiment 2

[0043] Weigh 15g of the product of Example 1 into a reaction flask, add 15g of sodium hydroxide, 65ml of N,N-dimethylformamide (DMF), stir at 20°C for 30min, add 4.04g of 4-methyl-benzene dissolved in The solution of sulfonyl chloride in 15ml DMF was stirred at 20°C for 3h, neutralized with HCl, dialyzed, concentrated, and freeze-dried to obtain p-toluenesulfonylated β-cyclodextrin polymer.

Embodiment 3

[0045] Dissolve 5 g of the dried product in Example 2 in 100 ml of N, N-dimethylformamide (DMF), add anhydrous 3 g of NaI, and react for 5 hours under magnetic stirring at 90 ° C. After cooling, rotary evaporation removes the solvent. Wash with acetone to remove excess NaI, dissolve the precipitate in a small amount of water, filter, and wash the filtrate with acetone to obtain a white powder.

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