Positive pole piece of lithium-sulphur battery and preparation method thereof

Abstract

The invention relates to a positive pole piece of a lithium-sulfur battery based on an L-cysteine or L-cystine agent as an additive and a preparation method thereof. According to the method, based on gelatin as a binder, the L-cysteine or L-cystine additive is introduced, thus the redox property of a sulphur electrode is obviously improved, and the electrochemistry reversibility and circulation stability of the lithium-sulfur battery are significantly improved.

Description

Technical field:

[0001] The invention relates to a lithium-sulfur battery positive electrode sheet with L-cysteine ​​or L-cystine as an additive and a preparation method thereof. Background technique:

[0002] The theoretical specific capacity of elemental sulfur is 1672mAh / g, and the theoretical specific energy is 2600W / kg, which is the highest among all known lithium battery cathode materials. At the same time, elemental sulfur is abundant and harmless to the environment, making lithium-sulfur secondary batteries a research hotspot in recent years.

[0003] The cathode material of a general lithium-sulfur battery consists of an active material, a conductive agent and a binder. Traditional binders, such as PEO, styrene-butadiene rubber or polyvinylidene fluoride (PVDF), are dissolved in non-aqueous solvents, and then mixed with sulfur and conductive agents to form a slurry. These binders are added in a large amount in the positive electrode material, and the prepared slur...

Examples

Embodiment 1

[0026] A gelatin aqueous solution with a mass percent concentration of 2% was prepared, and then L-cysteine ​​was added, and the mass ratio of L-cysteine ​​to gelatin was 0.1:10. Use 1mol / L KOH solution to adjust pH=7, set aside.

[0027] Preparation of positive electrode sheet: Grind sublimated sulfur and acetylene black evenly, and then add them to the above-mentioned mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:30:10:0.1, continue to grind, and make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method, and after air-drying at room temperature, the Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0028] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the electrolyte is 1mol / L LiClO 4 solu...

Embodiment 2

[0030] A gelatin aqueous solution with a mass percent concentration of 2% was prepared, and then L-cysteine ​​was added, and the mass ratio of L-cysteine ​​to gelatin was 0.1:10. Use 1mol / L KOH solution to adjust pH=10, set aside.

[0031]Preparation of positive electrode sheet: Grind sublimated sulfur and acetylene black evenly, and then add the above mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:30:10:0.1. Continue to grind to make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method. After air-drying at room temperature, the Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0032] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the electrolyte is 1mol / L LiClO 4 solution, the solvent is DME...

Embodiment 3

[0034] Prepare an aqueous gelatin solution with a mass percent concentration of 3%, and then add L-cysteine, and the mass ratio of L-cysteine ​​to gelatin is 0.2:15. Adjust the pH to 7 with 0.1mol / L LiOH solution and set aside.

[0035] Preparation of the positive pole piece: Preparation of the positive pole piece: grind the sublimated sulfur and acetylene black evenly and add them into the above-mentioned mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:40:15:0.2, continue to grind, and make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method, and after air-drying at room temperature, in Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0036] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the...

Technical field:

[0001] The invention relates to a lithium-sulfur battery positive electrode sheet with L-cysteine ​​or L-cystine as an additive and a preparation method thereof. Background technique:

[0002] The theoretical specific capacity of elemental sulfur is 1672mAh / g, and the theoretical specific energy is 2600W / kg, which is the highest among all known lithium battery cathode materials. At the same time, elemental sulfur is abundant and harmless to the environment, making lithium-sulfur secondary batteries a research hotspot in recent years.

[0003] The cathode material of a general lithium-sulfur battery consists of an active material, a conductive agent and a binder. Traditional binders, such as PEO, styrene-butadiene rubber or polyvinylidene fluoride (PVDF), are dissolved in non-aqueous solvents, and then mixed with sulfur and conductive agents to form a slurry. These binders are added in a large amount in the positive electrode material, and the prepared slur...

Examples

Embodiment 1

[0026] A gelatin aqueous solution with a mass percent concentration of 2% was prepared, and then L-cysteine ​​was added, and the mass ratio of L-cysteine ​​to gelatin was 0.1:10. Use 1mol / L KOH solution to adjust pH=7, set aside.

[0027] Preparation of positive electrode sheet: Grind sublimated sulfur and acetylene black evenly, and then add them to the above-mentioned mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:30:10:0.1, continue to grind, and make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method, and after air-drying at room temperature, the Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0028] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the electrolyte is 1mol / L LiClO 4 solu...

Embodiment 2

[0030] A gelatin aqueous solution with a mass percent concentration of 2% was prepared, and then L-cysteine ​​was added, and the mass ratio of L-cysteine ​​to gelatin was 0.1:10. Use 1mol / L KOH solution to adjust pH=10, set aside.

[0031]Preparation of positive electrode sheet: Grind sublimated sulfur and acetylene black evenly, and then add the above mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:30:10:0.1. Continue to grind to make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method. After air-drying at room temperature, the Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0032] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the electrolyte is 1mol / L LiClO 4 solution, the solvent is DME...

Embodiment 3

[0034] Prepare an aqueous gelatin solution with a mass percent concentration of 3%, and then add L-cysteine, and the mass ratio of L-cysteine ​​to gelatin is 0.2:15. Adjust the pH to 7 with 0.1mol / L LiOH solution and set aside.

[0035] Preparation of the positive pole piece: Preparation of the positive pole piece: grind the sublimated sulfur and acetylene black evenly and add them into the above-mentioned mixed solution of L-cysteine ​​and gelatin. The mass ratio of sublimated sulfur, acetylene black, gelatin, and cysteine ​​is 60:40:15:0.2, continue to grind, and make a uniform positive electrode slurry, which is coated on the aluminum foil current collector by the scraper method, and after air-drying at room temperature, in Dry it in a vacuum oven for 10 hours, and press it into a disc with a diameter of 1.2 cm.

[0036] Use the pole piece prepared above as the positive electrode, the negative electrode is lithium metal, the diaphragm is made of polypropylene film, and the...

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