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

• US 10,069,133 B2
• Filed: 12/02/2016
• Issued: 09/04/2018
• 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:
  US15/367,367
• Publication Number:
  US 20170162857A1
• Time in Patent Office: 641 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, a polyvinyl alcohol binder and sulfur, and then treating the electrode with a gaseous oxidant to thereby create an oxidized surface. The resulting iron electrode is treated 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. A process for preparing an electrode comprising an iron active material, a polyvinyl alcohol binder and sulfur, which comprises:

i) fabricating an electrode comprising an iron active material, a polyvinyl alcohol binder and sulfur, and

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

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

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

4. The process of claim 1, wherein the electrode is treated 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 process of claim 4, wherein the oxidation state of the treated iron active material is +2, +2/+3, +3 or +4.

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

7. The process of claim 6, wherein the conductive additive comprises nickel, copper or carbon black.

8. The process of claim 1, wherein the electrode comprises an iron active material comprising about:

50-90 wt % iron powder

5-30 wt % nickel powder

0.5-5.0 w % polyvinyl alcohol binder, and

0.25-20 w % sulfur.

9. The process 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, polyvinyl alcohol binder and sulfur.

10. The process of claim 9, wherein the substrate is comprised of nickel plated steel.

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