Accelerated formation and increased performance in chemically pre-formed (CPF) iron negative electrodes

Patent metadata

Field	Value
Publication number	US-10629888-B2
Application number	US-201816116336-A
Country	US
Kind code	B2
Filing date	Aug 29, 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 surface of the electrode with an 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. A electrode which has not been subject to a charge-discharge cycle, comprising an iron active material, a polyvinyl alcohol binder and sulfur, which electrode is prepared by a process comprising:
i) fabricating an electrode comprising an iron active material, polyvinyl alcohol and sulfur, and
ii) treating the surface of the electrode with an oxidant to thereby create an oxidized surface prior to the electrode being subjected to a charge-discharge cycle.

2. The electrode of claim 1 , wherein the oxidation state of the oxidized iron surface is +2, +2/+3, +3 or +4.

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

4. The electrode of claim 3 , wherein the conductive additive comprises nickel, or copper or carbon black.

5. The electrode of claim 1 , wherein the electrode comprises about:
50-90 wt % iron powder,
5-30 wt % nickel powder,
0.5-5.0 wt % binder, and
0.25-20 wt % sulfur.

6. 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.

7. The electrode of claim 6 , wherein the substrate is comprised of nickel plated steel.

8. The electrode of claim 2 , 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

• H01M4/26

  Processes of manufacture · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M4/049 Primary

  Manufacturing of an active layer by chemical means · CPC title

• H01M4/5815

  Sulfides · CPC title

• H01M4/248

  Iron electrodes · CPC title