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

• US 10,629,889 B2
• Filed: 08/30/2018
• Issued: 04/21/2020
• 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): Oyer, Andrew J.
• Application Number:
  US16/117,977
• Publication Number:
  US 20180375087A1
• Time in Patent Office: 600 Days
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 2201/03 Oxygen
• CPC Class Codes: B22F 2301/15 Nickel or cobalt
• CPC Class Codes: B22F 2301/35 Iron
• CPC Class Codes: B22F 2302/45 Others, including non-metals
• CPC Class Codes: B22F 2303/01 Main component
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: C23C 8/14 Oxidising of ferrous surfaces
• CPC Class Codes: C23C 8/18 Oxidising of ferrous surfaces
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/049 Manufacturing of an active layer by chemical means
• 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 4/38 of elements or alloys
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: H01M 4/626 Metals
• CPC Class Codes: H01M 4/661 : Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/662 : Alloys collectors of lead alloys H01M4/685
• CPC Class Codes: H01M 4/667 : in the form of layers, e.g. coatings
• 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 electrode with a gaseous oxidant 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, which electrode is prepared by a process comprising:

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

ii) treating the electrode with a gaseous oxidant to thereby create an oxidized surface prior to any charge-discharge cycle.

2. The electrode of claim 1, therein the oxidant comprises ozone, chlorine, or nitrous oxide.

3. The electrode of claim 2, wherein the oxidant comprises ozone.

4. The electrode of claim 1, wherein the electrode surface has been treated with a gaseous oxidant 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.

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

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

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

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

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

10. 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.

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

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

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

14. The electrode of claim 1, wherein the electrode surface is treated with the gaseous oxidant by exposing the surface of the electrode to the gaseous oxidant in a closed environment.