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

Patent metadata

Field	Value
Publication number	US-2017162857-A1
Application number	US-201615367367-A
Country	US
Kind code	A1
Filing date	Dec 2, 2016
Priority date	Sep 5, 2013
Publication date	Jun 8, 2017
Grant date	—

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.

First claim

What is claimed is:

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.

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 has been 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, or 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 comprise a single layer of conductive substrate coated on at least one side with a coating comprising the iron active material.

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%.

Assignees

• Encell Technology Inc

Inventors

• Ogg Randy Gene
• Roders Michael
• Meese Michael

Classifications

• H01M4/248

  Iron electrodes · CPC title

• H01M4/621

  Binders · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• C23C8/14

  Oxidising of ferrous surfaces · CPC title

• C23C8/18

  Oxidising of ferrous surfaces · CPC title