Fast response, high rate, gas diffusion electrode and method of making same
First Claim
1. A fast response, high current density oxygen cathode comprising:
- a form-stable, electrically conductive, wetproofing layer composed essentially of an intimate, consolidated and heat sintered mixture of carbon black and particulate hydrophobic polymeric binder derived predominantly from tetrafluoroethylene, having at least one anisometric electroconductive reinforcing material incorporated therein; and
, directly adhered to one surface of said wetproofing layer, a porous active layer having a thickness between about 0.03 and about 0.1 millimeter and composed essentially of a mixture of particles of a polymer of tetrafluoroethylene and cobalt catalyst-containing particles of an active carbon predominantly of a size between about 2 and about 20 micrometers and having a B.E.T. surface area of over about 1000 m2 /gram.
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Abstract
Disclosed are gas fed, porous electrodes capable of steady, high current density operation for practical periods of service, e.g. as oxygen cathodes in metal-air batteries. The subject electrodes feature at least two bonded composite layers, one of which is a form-stable, conductive wetproofing layer while the other is an unusually thin active layer containing active carbon particles predominantly between about 2 and about 20 micrometers and having a high internal surface area, e.g. a B.E.T. surface area of over 1000 m2 /gram. A simple and highly successful method of preparing such electrodes is also disclosed, which avoids the necessity of separately forming and handling the thin active layer.
68 Citations
19 Claims
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1. A fast response, high current density oxygen cathode comprising:
- a form-stable, electrically conductive, wetproofing layer composed essentially of an intimate, consolidated and heat sintered mixture of carbon black and particulate hydrophobic polymeric binder derived predominantly from tetrafluoroethylene, having at least one anisometric electroconductive reinforcing material incorporated therein; and
, directly adhered to one surface of said wetproofing layer, a porous active layer having a thickness between about 0.03 and about 0.1 millimeter and composed essentially of a mixture of particles of a polymer of tetrafluoroethylene and cobalt catalyst-containing particles of an active carbon predominantly of a size between about 2 and about 20 micrometers and having a B.E.T. surface area of over about 1000 m2 /gram. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- a form-stable, electrically conductive, wetproofing layer composed essentially of an intimate, consolidated and heat sintered mixture of carbon black and particulate hydrophobic polymeric binder derived predominantly from tetrafluoroethylene, having at least one anisometric electroconductive reinforcing material incorporated therein; and
Specification