Carbon-sulphur composite used for cathode material of lithium sulphur battery as well as preparation method and application thereof

Abstract

The invention relates to a carbon-sulphur composite used for a cathode material of a lithium sulphur battery as well as a preparation method and application thereof. The carbon-sulphur composite comprises a carbon material and elemental sulphur, wherein the carbon material is formed by doping mesoporous carbon with the aperture of 2-5nm and electroconductive carbon with the aperture of 30-70nm, and the electroconductive carbon with the aperture of 30-70nm contains micropores with the aperture of 0.5-1.7nm; and the elemental sulphur accounts for 10-90wt% of the total quantity of the composite. Abundant micropores guarantee that the carbon material has larger specific surface, adsorption capacity to polysulphide is stronger, and dissolution of the polysulphide can be effectively limited, so that stability of a sulphur electrode is improved. Meso pores in porous distribution can load more sulphur active substances, electrochemical capacity of a composite material is improved, and diffusion and transmission of lithium ions and electrolyte solution can be facilitated, so that reduction polarization of the elemental sulphur is reduced and discharge plateau of the elemental sulphur is improved.

Description

technical field

[0001] The invention relates to a key material of a lithium-sulfur secondary battery and a preparation method thereof, in particular to a carbon-sulfur compound used as a positive electrode material of a lithium-sulfur battery, a preparation method and an application thereof. Background technique

[0002] Lithium-sulfur battery is a secondary battery with metal lithium as the negative electrode and elemental sulfur as the positive electrode. Its specific energy can theoretically reach 2600Wh / kg, which is much larger than any commercial secondary battery currently used. In addition to high energy density, lithium-sulfur batteries also have the advantages of less environmental pollution, good safety performance, and the positive electrode material elemental sulfur has abundant sources and low price. Therefore, lithium-sulfur batteries will have broad application prospects in the field of new energy. As a power battery, it can be widely used in plug-in hybrid v...

Examples

Embodiment 1

[0037] Mix 1g of tri-block copolymer (P123), 7.5ml of water, 30g of 2.0mol / L HCl, and dissolve with magnetic stirring at 38°C for 4 hours, then add 2.08g of tetraethyl orthosilicate (TEOS) dropwise to the solution. Continue to stir After 20 hours, it was crystallized in a high-pressure hydrothermal reactor at 100°C for 72 hours, cooled, filtered, washed, and dried. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0038] In addition, SBA-15 is used as a template and sucrose as a carbon source to prepare mesoporous carbon materials. The steps are: dissolve 1.25g of sucrose in 5g of water, add 1g of mesoporous silica template, and slowly add 0.14g of 98% concentrated Sulfuric acid. Ultrasound mixed evenly, carbonized at 100°C for 6 hours, and carbonized at 160°C for 6 hours; another 0.75g of sucrose was dissolved in 5g of distilled water, added to the above product, and 0...

Embodiment 2

[0044] Mix 1g of P123, 7.5ml of water and 30g of 2.0mol / L HCl, stir and dissolve at 38°C for 4 hours, then add 4g of TEOS dropwise to the solution. After stirring for 10 minutes, crystallize in a high-pressure hydrothermal reactor at 100°C 24h, cooling, filtering, washing and drying. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0045] In addition, SBA-15 was used as a template, and sucrose was used as a carbon source to prepare mesoporous carbon materials. The steps were: dissolve 1.25g sucrose in 5g water, add 1g mesoporous silica template, and slowly add 0.14g concentrated sulfuric acid. Ultrasound Mix evenly, carbonize at 100°C for 8 hours, and carbonize at 160°C for 8 hours; add 0.75g of sucrose to 5g of distilled water and add to the above product, slowly add 0.08g of concentrated sulfuric acid. Carbonize for 8 hours, and then continue to carbonize at 160°C f...

Embodiment 3

[0050] Mix 1 g of P123, 7.5 ml of water, 30 g of 2.0 mol / L HCl, and dissolve with magnetic stirring at 40°C for 4 hours, then add 1.0 g of TEOS dropwise to the solution. After continuing to stir for 20h, crystallize in a high-pressure hydrothermal reactor at 100°C for 48h, cool, filter, wash, and dry. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0051] In addition, SBA-15 is used as a template and hot phenolic resin is used as a carbon source to prepare mesoporous carbon materials. The steps are: dissolve 1.25g of hot phenolic resin in 5g of water, add 1g of mesoporous silica template, and slowly drop 0.14g Concentrated sulfuric acid. Ultrasonic mixing, carbonization at 100°C for 6 hours, and carbonization at 160°C for 6 hours; another 0.75g of hot phenolic resin dissolved in 5g of distilled water, added to the above product, slowly added dropwise 0.08g of concentr...

technical field

[0001] The invention relates to a key material of a lithium-sulfur secondary battery and a preparation method thereof, in particular to a carbon-sulfur compound used as a positive electrode material of a lithium-sulfur battery, a preparation method and an application thereof. Background technique

[0002] Lithium-sulfur battery is a secondary battery with metal lithium as the negative electrode and elemental sulfur as the positive electrode. Its specific energy can theoretically reach 2600Wh / kg, which is much larger than any commercial secondary battery currently used. In addition to high energy density, lithium-sulfur batteries also have the advantages of less environmental pollution, good safety performance, and the positive electrode material elemental sulfur has abundant sources and low price. Therefore, lithium-sulfur batteries will have broad application prospects in the field of new energy. As a power battery, it can be widely used in plug-in hybrid v...

Examples

Embodiment 1

[0037] Mix 1g of tri-block copolymer (P123), 7.5ml of water, 30g of 2.0mol / L HCl, and dissolve with magnetic stirring at 38°C for 4 hours, then add 2.08g of tetraethyl orthosilicate (TEOS) dropwise to the solution. Continue to stir After 20 hours, it was crystallized in a high-pressure hydrothermal reactor at 100°C for 72 hours, cooled, filtered, washed, and dried. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0038] In addition, SBA-15 is used as a template and sucrose as a carbon source to prepare mesoporous carbon materials. The steps are: dissolve 1.25g of sucrose in 5g of water, add 1g of mesoporous silica template, and slowly add 0.14g of 98% concentrated Sulfuric acid. Ultrasound mixed evenly, carbonized at 100°C for 6 hours, and carbonized at 160°C for 6 hours; another 0.75g of sucrose was dissolved in 5g of distilled water, added to the above product, and 0...

Embodiment 2

[0044] Mix 1g of P123, 7.5ml of water and 30g of 2.0mol / L HCl, stir and dissolve at 38°C for 4 hours, then add 4g of TEOS dropwise to the solution. After stirring for 10 minutes, crystallize in a high-pressure hydrothermal reactor at 100°C 24h, cooling, filtering, washing and drying. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0045] In addition, SBA-15 was used as a template, and sucrose was used as a carbon source to prepare mesoporous carbon materials. The steps were: dissolve 1.25g sucrose in 5g water, add 1g mesoporous silica template, and slowly add 0.14g concentrated sulfuric acid. Ultrasound Mix evenly, carbonize at 100°C for 8 hours, and carbonize at 160°C for 8 hours; add 0.75g of sucrose to 5g of distilled water and add to the above product, slowly add 0.08g of concentrated sulfuric acid. Carbonize for 8 hours, and then continue to carbonize at 160°C f...

Embodiment 3

[0050] Mix 1 g of P123, 7.5 ml of water, 30 g of 2.0 mol / L HCl, and dissolve with magnetic stirring at 40°C for 4 hours, then add 1.0 g of TEOS dropwise to the solution. After continuing to stir for 20h, crystallize in a high-pressure hydrothermal reactor at 100°C for 48h, cool, filter, wash, and dry. The dried product was calcined at 550° C. for 5 hours to remove the high-molecular substances in the silica to obtain the mesoporous silica material SBA-15.

[0051] In addition, SBA-15 is used as a template and hot phenolic resin is used as a carbon source to prepare mesoporous carbon materials. The steps are: dissolve 1.25g of hot phenolic resin in 5g of water, add 1g of mesoporous silica template, and slowly drop 0.14g Concentrated sulfuric acid. Ultrasonic mixing, carbonization at 100°C for 6 hours, and carbonization at 160°C for 6 hours; another 0.75g of hot phenolic resin dissolved in 5g of distilled water, added to the above product, slowly added dropwise 0.08g of concentr...

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