# US 4,391,668 A · Mixed oxide oxygen electrode

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- Number: US 4,391,668 A
- Document ID: US4391668A
- Status: Granted
- Kind: A
- Application number: 06/256,665
- Filed: 1981-04-22
- Granted: 1983-07-05
- Earliest claimed: 1980-09-02
- Assignees: Her Majesty the Queen in right of Canada, as represented by the Minister of National Defence
- Inventors: William A. Armstrong
- Web page: https://patentgrep.com/patent/US4391668A

## CPC

- H01M 4/9016: {Oxides, hydroxides or oxygenated metallic salts}
- C25B 11/057: consisting of a single element or compound
- C25B 11/0771: {of the spinel type}
- C25B 11/095: at least one of the compounds being organic
- H01M 4/8821: {Wet proofing}
- H01M 4/8882: {Heat treatment, e.g. drying, baking}
- H01M 4/8892: {Impregnation or coating of the catalyst layer, e.g. by an ionomer}
- H01M 4/8896: {Pressing, rolling, calendering (membrane electrode assemblies H01M8/1004)}
- C25B 11/061: Metal or alloy
- H01M 2004/8689: {Positive electrodes}
- H01M 2300/0014: Alkaline electrolytes
- Y02E 60/50: Fuel cells
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The invention disclosed is a novel method for the preparation of a nickel/cobalt oxide impregnated nickel plaque material involving a single oxidation step. The nickel plaque material is cleaned, impregnated with an aqueous cobalt nitrate solution and dried. The nickel/cobalt oxide is then formed in a single oxidation step.

## Claims

### Claim 1

A method for the preparation of a nickel/cobalt oxide impregnated nickel plaque material, comprising
(a) providing a substantially oxide free sintered nickel plaque material;
(b) dipping the nickel plaque in an aqueous solution of cobalt nitrate and polytetrafluoroethylene as a wet-proofing agent;
(c) drying the cobalt nitrate impregnated plaque so formed; and
(d) heat treating at about 200.degree. to about 250.degree. C. for about 1 to 8 hours, to form the nickel/cobalt oxide impregnated nickel plaque material.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the concentration of the aqueous cobalt nitrate is 200 to 800 mg/ml.

### Claim 3 (depends on 2)

A method according to claim 2, wherein the concentration of the aqueous cobalt nitrate is about 800 mg/ml.

### Claim 4 (depends on 2)

A method according to claim 2, wherein the heat treatment is effected at about 250.degree. C. for about 4 hours in a drying furnace.

### Claim 5 (depends on 1)

A method according to claim 1 wherein step (c) the plaque is air dried at about 125.degree. C. for about 12 hours.

### Claim 6 (depends on 1, 2, 4)

A method according to claim 1, 2 or 4, wherein immediately prior to step (a) the nickel plaque is subjected to a cleaning treatment to remove oxides which may be on the surface of the plaque.

### Claim 7 (depends on 1)

A method according to claim 1, wherein the nickel plaque material is in the form of a flat plate and including the additional steps of
(g) covering one side of the plate with a polytetrafluoroethylene membrane; and
(h) hot pressing the membrane onto the plate.

### Claim 8

A method for the preparation of a nickel/cobalt oxide impregnated nickel plaque material, comprising the steps of:
(a) providing a substantially oxide-free sintered nickel plaque material;
(b) dipping the nickel plaque in an aqueous solution of cobalt nitrate;
(c) drying the cobalt nitrate impregnated plaque so formed;
(d) heat treating at about 200.degree. to 250.degree. C. for about 1 to 8 hours, to form the nickel/cobalt oxide impregnated nickel plaque material;
(e) covering one side of the plate with a polytetrafluoroethylene membrane;
(f) cold pressing the membrane onto the plate;
(g) exposing the other side of the plate to aqueous cobalt nitrate and polytetrafluoroethylene solution;
(h) drying the plate;
(i) removing the polytetrafluoroethylene covering from said one side of the plate;
(j) heat treating the plate at about 250.degree. C. for about 3 hours, to form a plate wet-proofed only on said other side of the plate;
(k) covering the wet-proofed side of the plate with a polytetrafluoroethylene membrane; and
(l) hot-pressing the membrane onto the plate.

### Claim 9 (depends on 8)

A method according to claim 8 wherein the concentration of the aqueous cobalt nitrate is 200 to 800 mg/ml.