Methods of fabricating rechargeable positive electrodes

• US 5,582,623 A
• Filed: 06/07/1995
• Issued: 12/10/1996
• Est. Priority Date: 11/23/1994
• Status: Expired due to Term

• Current Assignee: PolyPlus Battery Company
• Original Assignee: PolyPlus Battery Company
• Inventors: Chu, May-Ying
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US08/479,687
• Time in Patent Office: 552 Days
• Field of Search: 429/218, 429/212, 429/213, 429/233, 429/192, 429/190, 429/194, 429/104, 429/102, 429/103, 429/105, 136/238, 136/263, 29/623.1, 29/623.5
• US Class Current: 29/623.1
• CPC Class Codes: H01M 10/05 Accumulators with non-aqueous electrolyte H01M10/39 takes precedence
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0565 Polymeric materials, e.g. gel-type or solid-type
• CPC Class Codes: H01M 10/36 Accumulators not provided for in groups H01M10/05-H01M10/34
• CPC Class Codes: H01M 10/39 working at high temperature
• CPC Class Codes: H01M 10/3909 Sodium-sulfur cells
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 2300/0065 Solid electrolytes
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/04 Processes of manufacture in general
• CPC Class Codes: H01M 4/0404 by coating on electrode collectors
• CPC Class Codes: H01M 4/0409 by a doctor blade method, slip-casting or roller coating
• CPC Class Codes: H01M 4/0411 by extrusion
• CPC Class Codes: H01M 4/0414 by screen printing
• CPC Class Codes: H01M 4/0416 involving impregnation with a solution, dispersion, paste or dry powder H01M4/0438 takes precedence
• CPC Class Codes: H01M 4/0421 involving vapour deposition
• CPC Class Codes: H01M 4/0426 Sputtering
• CPC Class Codes: H01M 4/043 involving compressing or compaction
• CPC Class Codes: H01M 4/0435 : Rolling or calendering
• CPC Class Codes: H01M 4/13 : Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/38 : of elements or alloys
• CPC Class Codes: H01M 4/382 : Lithium H01M4/405 takes precedence
• CPC Class Codes: H01M 4/581 : Chalcogenides or intercalation compounds thereof
• CPC Class Codes: H01M 4/5815 : Sulfides
• CPC Class Codes: H01M 4/60 : of organic compounds
• CPC Class Codes: H01M 4/621 : Binders
• CPC Class Codes: H01M 4/624 : Electric conductive fillers
• CPC Class Codes: H01M 4/625 : Carbon or graphite
• CPC Class Codes: H01M 4/626 : Metals
• CPC Class Codes: H01M 50/46 : Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 6/168 : by additives
• CPC Class Codes: H01M 6/18 : with solid electrolyte
• CPC Class Codes: H01M 6/181 : with polymeric electrolytes
• CPC Class Codes: H01M 6/188 : Processes of manufacture
• CPC Class Codes: H01M 6/40 : Printed batteries , e.g. thin film batteries
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y10T 29/49108 : Electric battery cell making
• CPC Class Codes: Y10T 29/49115 : including coating or impregnating

Abstract

Disclosed are methods of making solid-phase active-sulfur-based composite electrodes. The method begins with a step of combining the electrode components (including an electrochemically active material, an electronic conductor, and an ionic conductor) in a slurry. Next, the slurry is homogenized such that the electrode components are well mixed and free of agglomerates. Very soon thereafter, before the electrode components have settled or separated to any significant degree, the slurry is coated on a substrate to form a thin film. Finally, the coated film is dried to form the electrode in such a manner that the electrode components do not significantly redistribute.

Claims

1. A method of forming an active-sulfur-containing electrode, the method comprising the following steps:

combining active-sulfur, an electronic conductor, and an ionic conductor to form a mixture;

homogenizing the mixture to form a homogeneous mixture; and

forming the active-sulfur-containing electrode from said homogeneous mixture, wherein said active-sulfur-containing electrode has at least about 10% of its active-sulfur accessible to electrons and ionic charge carriers.

2. The method of claim 1 wherein the method includes a step of forming a slurry by combining the active-sulfur, the electronic conductor, and the ionic conductor with a liquid.

3. The method of claim 2 wherein said step of homogenizing involves agitating the slurry to form said homogeneous mixture.

4. The method of claim 2 wherein, in the step of forming a slurry, soluble and insoluble components of the mixture are combined with said liquid at different times.

5. The method of claim 2 wherein the slurry is formed from a dispersant in addition to the active-sulfur, the electronic conductor, the ionic conductor, and the liquid.

6. The method of claim 1 wherein said step of homogenizing comprises homogenizing a solid phase mixture containing the active-sulfur, the electronic conductor, and the ionic conductor.

7. The method of claim 1 wherein the step of forming the active-sulfur-containing electrode includes the step of applying a layer of said homogeneous mixture to a substrate.

8. The method of claim 1 wherein the mixture is formed from a polydisulfide material in addition to the active-sulfur, the electronic conductor, and the ionic conductor.

9. The method of claim 1 wherein the electronic conductor employed in the step of combining is selected from the group consisting of carbon and conductive polymers.

10. The method of claim 1 wherein the ionic conductor is a polyalkylene oxide.

11. The method of claim 1 further comprising a step of preparing an electrochemical cell containing said active-sulfur-containing electrode.

12. A method of forming an active-sulfur-containing electrode, the method comprising the following steps:

combining active-sulfur, an electronic conductor, and an ionic conductor to form a mixture;

homogenizing the mixture to form a homogeneous mixture; and

depositing a layer of said homogeneous mixture on a substrate by a technique that does not rely on capillary action to form said active-sulfur containing electrode, wherein said active-sulfur-containing electrode has at least about 10% of its active-sulfur is accessible to electrons and ionic charge carriers.

13. The method of claim 12 wherein the method includes a step of forming a slurry by combining the active-sulfur, the electronic conductor, and the ionic conductor with a liquid.

14. The method of claim 13 wherein the step of depositing includes a step of forming a slurry layer on the substrate.

15. The method of claim 14 further comprising a step of drying said slurry layer to form said active-sulfur-containing electrode.

16. The method of claim 15 wherein said step of drying includes the following steps:

drying the slurry layer under ambient conditions to form a partially dried layer; and

further drying the partially dried layer under a vacuum to form said active-sulfur-containing electrode.

17. The method of claim 14 wherein said slurry layer is formed on a current collector.

18. The method of claim 14 wherein said slurry layer is formed on a non-adhesive substrate.

19. The method of claim 18 further comprising the following steps:

drying said slurry layer to form the active-sulfur-containing electrode;

removing the active-sulfur-containing electrode from the non-adhesive substrate; and

affixing the active-sulfur-containing electrode to a current collector such that the active-sulfur-containing electrode is in electrical contact with the current collector.

20. The method of claim 14 wherein the slurry layer is continuously formed on the substrate which is continuously contacted with a source of slurry.

21. The method of claim 12 wherein the step of homogenizing comprises homogenizing a solid-phase mixture containing the active-sulfur, the electronic conductor, and the ionic conductor.

22. The method of claim 12 further comprising a step of preparing an electrochemical cell containing said active-sulfur-containing electrode.