Method for preparing sulfur-based cathode material

Patent metadata

Field	Value
Publication number	US-2017214040-A1
Application number	US-201715482024-A
Country	US
Kind code	A1
Filing date	Apr 7, 2017
Priority date	Oct 9, 2014
Publication date	Jul 27, 2017
Grant date	—

Abstract

A method for preparing sulfur-based cathode material is disclosed. First, polyacrylonitrile and sulfur according to a proportion are dissolved in a first solvent at a first temperature to obtain a first solution. Second, the first solution is transferred into a second solvent at a second temperature, to precipitate the polyacrylonitrile and sulfur to form a precipitated material. Third, the precipitated material is filtered and heated to produce a sulfurized polyacrylonitrile.

First claim

What is claimed is:

1 . A method for preparing sulfur-based cathode material, comprising:
dissolving polyacrylonitrile and elemental sulfur in a first solvent at a first temperature to obtain a first solution; transferring the first solution into a second solvent at a second temperature, to precipitate the polyacrylonitrile and the elemental sulfur to form a precipitated material, wherein the polyacrylonitrile and the elemental sulfur are insoluble in the second solvent, the second temperature is lower than the first temperature, and a temperature difference between the first temperature and the second temperature is equal to or greater than 50□; and filtering and heat treating the precipitated material to have a chemical reaction between the polyacrylonitrile and the elemental sulfur to produce a sulfurized polyacrylonitrile.

2 . The method of claim 1 , wherein the first temperature is greater than or equal to 100□ and less than or equal to 200□, and the second temperature is less than 50□.

3 . The method of claim 1 , wherein the sulfur and the polyacrylonitrile are dissolved in the first solvent according to a mass ratio in a range from about 1:1 to about 10:1.

4 . The method of claim 1 , wherein the sulfur and the polyacrylonitrile are dissolved in the first solvent according to a mass ratio in a range from about 2:1 to about 4:1.

5 . The method of claim 1 , wherein a total concentration of the sulfur and the polyacrylonitrile in the first solution is in a range from about 10 g/L to about 100 g/L.

6 . The method of claim 1 , wherein the first solvent is selected from the group consisting of N-methylpyrrolidone, dimethylformamide, dimethylsulfoxide, dimethylacetamide, and combinations thereof.

7 . The method of claim 1 , wherein the second solvent is selected from the group consisting of water, ethanol, methanol, acetone, n-hexane, cyclohexane, diethyl ether, and combinations thereof.

8 . The method of claim 1 , wherein a time of transferring the first solution into the second solvent is less than 10 seconds.

9 . The method of claim 8 , wherein in the transferring the first solution into a second solvent at a second temperature, the polyacrylonitrile coats an outer surface of the sulfur to form a core-shell structure, wherein the sulfur forms a core of the core-shell structure, and the polyacrylonitrile forms a shell of the core-shell structure.

10 . The method of claim 1 , wherein a volume ratio of the first solvent to the second solvent is in a range from about 1:1 to about 1:5.

11 . The method of claim 1 , wherein a temperature of the heat treating the precipitated material is greater than 100□, and a time of the heat treating the precipitated material is in a range from about 1 hour to about 10 hours.

12 . A method for preparing sulfur-based cathode material, comprising:
dissolving polyacrylonitrile and elemental sulfur according to a proportion in a first solvent at a first temperature to obtain a first solution; transferring the first solution into a second solvent at a second temperature, to precipitate the polyacrylonitrile and the elemental sulfur to form a precipitated material, wherein the polyacrylonitrile and the elemental sulfur are insoluble in the second solvent, the second temperature is lower than the first temperature, and a temperature difference between the first temperature and the second temperature is equal to or greater than 50□; and filtering and drying the precipitated material; heat treating the precipitated material to have a chemical reaction between the polyacrylonitrile and the elemental sulfur to produce a sulfurized polyacrylonitrile.

13 . The method of claim 12 , wherein a time of transferring the first solution into the second solvent is less than 10 seconds.

14 . The method of claim 13 , wherein in the transferring the first solution into a second solvent at the second temperature, the polyacrylonitrile coats an outer surface of the sulfur to form a core-shell structure, wherein the sulfur forms a core of the core-shell structure, and the polyacrylonitrile forms a shell of the core-shell structure.

Assignees

• Jiangsu Huadong Inst Of Li-Ion Battery Co Ltd
• Univ Tsinghua

Inventors

• Wang Li
• Wu fang-xu
• He xiang-ming
• Ren Yu-Mei
• Shang yu-ming
• Li Jian-Jun
• Gao Jian
• Wang yao-wu

Classifications

• H01M4/1399 Primary

  of electrodes based on electro-active polymers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/604

  containing aliphatic main chain polymers · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• C08F120/44

  Acrylonitrile · CPC title