Diamond Shamrock Corporation

Eltech Systems Corporation

Charles Grun

Frank Solomon

Marilyn J Niksa

James J Stewart

Donald W Abrahamson

A unitized electrode-intercell connector module is prepared for use in a bipolar electrode, especially for use in such electrode of the M-alkaline electrolyte-AgO types. In such special electrode, an imperforate foil, contacted with a conductive foam, is plated to a unitized, electrobonded assembly. Pyrolysis can lighten the assembly and may further provide for subsequent resistance to attack in an electrode environment. For the special electrode the reticulate portion of the assembly can be filled to provide an AgO electrode and the bipolar electrode completed by using a suitable electronegative metal on the foil side opposite from the AgO electrode.

Unitized electrode-intercell connector module

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 m.sup.2 /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.

Fast response, high rate, gas diffusion electrode and method of making

The disclosure is directed to preparing three-layer laminated electrodes suitable for use as oxygen (air) cathodes in chlor-alkali and other electrochemical cells, fuel cells and in other electrochemical applications. This three-layer laminate includes an active layer or sheet containing from about 60 to about 85 wt. % active carbon, the remainder being unsintered, fibrillated polytetrafluoroethylene in intimate admixture with said active carbon, said active layer laminated on its working surface to a current distributor and on its opposite surface to a porous, coherent, hydrophobic polytetrafluoroethylene-containing wetproofing layer.

Three layer laminate

The present disclosure is directed to an electrode active layer or sheet containing from about 60 to about 85 wt. % active carbon in intimate admixture with 15 to 40 wt. % fibrillated PTFE. This electrode has improved strength and is capable of operation at high current density with resistance to mechanical failure due to blistering of the electrode, and to a process for producing same. The process is characterized by combining a dilute dispersion of smaller polytetrafluoroethylene particles with a suspension of catalyzed or uncatalyzed larger active carbon particles to discontinuously coat active carbon with PTFE; fibrillating same; comminuting said fibrillated PTFE/active carbon mix; and then rolling same into a self-sustaining, coherent sheet form. Alternatively, the sheet form can be provided by deposition of the heat treated polytetrafluoroethylenated active carbon on a filter paper or like medium.

Method for forming an electrode active layer or sheet

This disclosure is directed to a one pass process for forming a porous, uniaxially oriented polytetrafluoroethylene sheet which is coherent and suitable for utilization as an electrode backing (wetproofing) sheet and the resulting backing sheet. Particulate PTFE is blended in an organic liquid medium to form a dispersion to which a pore-forming agent is added. After mixing, the organic liquid is removed and the dry mix is fibrillated, chopped and formed into a sheet by passing it once through heated rollers.

One pass process for forming electrode backing sheet

In a battery of electrochemical unit cells in which an active metal in powder form is an electrode, high rate reaction at high efficiency is achieved by slurrying the powdered metal in the cell electrolyte. The slurrying is carried out entirely within each cell so that no transfer of electrolyte to and from the cell during discharge is necessary. Such batteries are suitable for powering vehicles. A battery of such cells can be emptied and then refuelled either by pressure or by vacuum; in one embodiment the active metal can be regenerated in each of the cells from the discharge products formed therein.

Growing community of inventors

Matawan, NJ, United States of America

Charles Grun