High performance cermet electrodes

DETAILED DESCRIPTION What we claim is: 1.
A method of increasing the cell voltage of an electrochemical cell having a porous metal electrode in contact with a oxygen-transporting vapor deposited ceramic electrolyte comprising (A) heating said metal electrode particles to at least their oxidation temperature; (B) passing oxygen through said oxygen-transporting ceramic electrolyte to the surface of said metal electrode particles, whereby a portion of said metal electrode particles are oxidized, forming a metal oxide layer between said metal electrode particles and said electrolyte; and (C) reducing said metal oxide layer to said metal.
2.
A method according to claim 1 wherein said electrochemical cell is a fuel cell and said oxidation temperature is about 600.
degree.
to about 1200.
degree.
C.
3.
A method according to claim 1 wherein about 1 to about 100 atom % of said metal electrode is oxidized.
4.
A method according to claim 1 wherein said metal oxide layer is reduced by exposing it to a gaseous fuel at a temperature at which said metal oxide layer is reduced to metal.
5.
A method according to claim 4 wherein said fuel is selected from the group consisting of hydrogen, carbon monoxide, methane, and mixtures thereof.
6.
A method according to claim 4 wherein said oxide layer is reduced until the potential across said cell increases to about the potential of said fuel versus air.
7.
A method according to claim 1 wherein said metal oxide layer is reduced electrochemically by applying a reversed polarity from a DC power supply.
8.
A method according to claim 1 wherein said metal electrode particles are selected from the group consisting of nickel, cobalt, iron, copper, chromium, and mixtures and alloys thereof.
9.
A method according to claim 8 wherein said metal electrode particles are selected from the group consisting of nickel and cobalt, and mixtures and alloys thereof.
10.
A method according to claim 1 wherein said metal electrode particles are bonded to said electrolyte by means of a vapor deposited ceramic oxygen-conducting coating, which acts as a portion of said electrolyte