Method of making a porous electrode

• US 3,395,049 A
• Filed: 12/27/1963
• Issued: 07/30/1968
• Est. Priority Date: 07/15/1963
• Status: Expired due to Term

• Current Assignee: Charles E. Thompson
• Original Assignee: Charles E. Thompson
• Inventors: Thompson, Charles E.
• Application Number:
  US04/334,022
• Time in Patent Office: 1,677 Days
• US Class Current: 502/101
• CPC Class Codes: H01M 4/885 followed by reduction of the catalyst salt precursor
• CPC Class Codes: H01M 4/8875 Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support
• CPC Class Codes: H01M 4/8882 Heat treatment, e.g. drying, baking
• CPC Class Codes: H01M 4/8885 Sintering or firing
• CPC Class Codes: Y02E 60/50 Fuel cells

Claims

1. A METHOD OF MAKING A POROUS ELECTRODE WHICH COMPRISES:

(A) INTIMATELY MIXING FINELY DIVIDED HALOGENATED HYDROCARBON POLYMER, FINELY DIVIDED ELECTRICALLY CONDUCTIVE PARTICLES SELECTED FROM THE GROUP CONSISTING OF CARBON, CHARCOAL, GROUP VIII METALS, ALLOYS OF GROUP VIII METALS, OXIDES OF GROUP VIII METALS, GROUP VII (B) METALS, AND MIXTURES OF THE ABOVE AND PARTICULATE FILLER MATERIAL;

(B) PRESSING THE MIXTURE INTO A SHAPED FORM;

(C) SLOWLY HEATING THE SHAPED FORM TO A TEMPERATURE AT WHICH SAID FILLER MATERIAL BECOMES A GAS, SAID TEMPERATURE BEING SUBSTANTIALLY LOWER THAN THE SINTERING TEMPERATURE OF THE HALOGENATED HYDROCARBON POLYMER;

(D) ALLOWING THE GAS FORMED BY STEP (C) TO ESCAPE LEAVING A POROUS ELECTRODE;

(E) CONTACTING THE SIDE OF THE POROUS ELECTRODE THAT WILL NORMALLY BE IN CONTACT WITH THE ELECTROLYTE WHEN USED IN A FUEL CELL WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF WATER, SULFURIC ACID, PHOSPHORIC ACID, AQUEOUS SODIUM HYDROXIDE, AND AQUEOUS POTASSIUM HYDROXIDE AND CONTACTING THE OTHER SIDE OF THE ELECTRODE WITH A SOLUTION OF A SALT OF A CATALYTIC METAL, SAID METAL BEING SELECTED FROM THE GROUP CONSISTING OF GROUP VIII METALS, GROUP VII (B) METALS AND MIXTURES OF GROUP VIII AND GROUP VII (B) METALS IN A SOLVENT WHICH HAS A SURFACE TENSION OF BETWEEN ABOUT 1K TO 30 DYNES/CM. AND THEN;

(F) CONTACTING THE ELECTRODE WITH AN AQUEOUS SOLUTION OF A REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF SODIUM BOROHYDRIDE, ARYL SILANE, ALKYL SILANE, FORMALDEHYDE AND FORMIC ACID.

2. A METHOD AS CLAIMED IN CLAIM 1 WHICH COMPRISES THE ADDITIONAL STEP OF SINTERING THE POROUS ELECTRODE.