Process of preparing a chemically pre-formed (CPF) iron negative electrode with water

• US 10,301,714 B2
• Filed: 08/30/2018
• Issued: 05/28/2019
• Est. Priority Date: 09/05/2013
• Status: Active Grant

• Current Assignee: Encell Technology, Inc
• Original Assignee: Encell Technology, Inc
• Inventors: Ogg, Randy Gene, Roders, Michael, Meese, Michael
• Primary Examiner(s): Godenschwager, Peter F
• Assistant Examiner(s): Oyer, Andrew J.
• Application Number:
  US16/117,430
• Publication Number:
  US 20180371602A1
• Time in Patent Office: 271 Days
• CPC Class Codes: C23C 8/18 Oxidising of ferrous surfaces
• CPC Class Codes: H01M 4/0492 Chemical attack of the support material
• CPC Class Codes: H01M 4/248 Iron electrodes
• CPC Class Codes: H01M 4/26 Processes of manufacture
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Provided is a process for preparing an electrode comprising an iron active material. The process comprises first fabricating an electrode comprising an iron active material, and then treating the surface of the electrode with water to thereby create an oxidized surface. The resulting iron electrode is preconditioned prior to any charge-discharge cycle to have the assessable surface of the iron active material in the same oxidation state as in discharged iron negative electrodes active material.

Claims

1. An electrode which has not been subject to a charge-discharge cycle, comprising an iron active material, wherein the electrode is prepared by a process comprising:

i) fabricating an electrode comprising an iron active material, and

ii) treating the surface of the electrode with water to thereby create an oxidized surface prior to any charge-discharge cycle.

2. The electrode of claim 1, wherein the water comprises deionized water.

3. The electrode of claim 1, wherein the iron electrode has been treated with water prior to any charge-discharge cycle to have the accessible surface of the iron material in the same oxidation state as discharged iron negative electrode active material.

4. The electrode of claim 3, wherein the oxidation state of the oxidized iron active material is +2, +2/+3, +3 or +4.

5. The electrode of claim 1, wherein the electrode further comprises a polyvinyl alcohol binder.

6. The electrode of claim 5, wherein the electrode further comprises sulfur.

7. The electrode of claim 1, wherein the electrode further comprises a conductive additive.

8. The electrode of claim 7, wherein the conductive additive comprises nickel, or copper or carbon black.

9. The electrode of claim 1, wherein the electrode comprises about:

50-90 wt % iron powder

5-30 wt % nickel powder

0.5-5.0 w % binder, and

0.25-20 w % sulfur.

10. The electrode of claim 1, wherein the electrode comprises a single layer of conductive substrate coated on at least one side with a coating comprising the iron active material.

11. The electrode of claim 10, wherein the substrate is comprised of nickel plated steel.

12. The electrode of claim 1, wherein the porosity of the electrode is in the range of about 15-50%.

13. The electrode of claim 1, wherein the treatment of the surface of the electrode comprises coating, dipping, spraying or brushing the water on the electrode.

14. The electrode of claim 13, wherein the water is brushed on the surface of the electrode.

15. The electrode of claim 13, wherein the water is sprayed on the surface of the electrode.

16. The electrode of claim 13, wherein the electrode is dipped in water.

17. The electrode of claim 6, wherein the electrode comprises from 2.0-5.0 wt % polyvinyl alcohol binder.

18. The electrode of claim 17, wherein the electrode comprises about 3.5 wt % polyvinyl alcohol binder.

19. The electrode of claim 9, wherein the electrode comprises from 2.0-5.0 wt % polyvinyl alcohol binder.

20. The electrode of claim 19, wherein the electrode comprises about 3.5 wt % polyvinyl alcohol binder.