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

Patent metadata

Field	Value
Publication number	US-10629889-B2
Application number	US-201816117977-A
Country	US
Kind code	B2
Filing date	Aug 30, 2018
Priority date	Sep 5, 2013
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

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.

First claim

What is claimed is:

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.

Assignees

• Encell Technology Inc

Inventors

• Ogg Randy Gene
• Roders Michael
• Meese Michael

Classifications

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/667

  in the form of layers, e.g. coatings · CPC title

• H01M4/626

  Metals · CPC title

• C23C8/18

  Oxidising of ferrous surfaces · CPC title

• H01M4/622

  being polymers · CPC title