FUEL CELL CATHODES
The present invention relates to a method of producing a fuel cell cathode, fuel cell cathodes, and fuel cells comprising same.
1 . A method of producing a fuel cell cathode, the method comprising the steps of:
(i) providing a primary layer comprising LSCF on a dense electrolyte layer;
(ii) isostatically pressing said primary layer in the pressure range 10-300 MPa;
(iii) providing on said pressed primary layer a current collecting layer comprising a perovskite-based electrode, to define a bi-layer cathode; and
(iv) firing said bi-layer cathode in a reducing atmosphere.
2 - 29 . (canceled)
30 . A method according to claim 1 , wherein said perovskite-based electrode comprises LSCF.
31 . A method according to claim 1 , said primary layer comprising an LSCF/CGO composite.
32 . A method according to claim 1 , said primary layer having a thickness of about 0.5-20 μm.
33 . A method according to claim 32 , said primary layer having a thickness of about 1-10 μm.
34 . A method according to claim 33 , said primary layer having a thickness of about 1.5-5 μm.
35 . A method according to claim 1 , said isostatic pressing being cold isostatic pressing.
36 . A method according to claim 1 , said isostatic pressing being performed at a pressure of about 10-300 MPa.
37 . A method according to claim 36 , said isostatic pressing being performed at a pressure of about 20-100 MPa.
38 . A method according to claim 37 , said isostatic pressing being performed at a pressure of about 30-70 MPa.
39 . A method according to claim 1 , said current collecting layer having a thickness of about 5-100 μm.
40 . A method according to claim 39 , said current collecting layer having a thickness of about 10-70 μm.
41 . A method according to claim 40 , said current collecting layer having a thickness of about 30-50 μm.
42 . A method according to claim 1 , wherein said bi-layer cathode is fired at a temperature of about 700-900° C.
43 . A method according to claim 42 , wherein said bi-layer cathode is fired at a temperature of about 800-900° C.
44 . A method according to claim 1 , wherein said bi-layer cathode is fired in the pO 2 range of about 10 −10 -10 −20 atm.
45 . A method according to claim 44 , wherein said bi-layer cathode is fired under a dilute, buffered H 2 /H 2 O atmosphere.
46 . A method according to claim 1 , wherein said bi-layer cathode is re-oxidized after being fired in said reducing atmosphere.
47 . A method according to claim 46 , wherein said bi-layer cathode is re-oxidized at a temperature of about 700° C.
48 . A method according to claim 1 , wherein said bi-layer cathode is fired under a dilute air/Argon mixed atmosphere or air/Nitrogen mixed atmosphere.
49 . A method according to claim 48 , wherein said bi-layer cathode is fired in the pO 2 range of about 10 −1 -10 −10 atm.
50 . A method according to claim 49 , wherein said bi-layer cathode is fired in the pO 2 range of about 10 −1 -10 −5 atm.
51 . A method according to claim 1 , wherein each of said layers is deposited by spray deposition or screen-printing.
52 . A fuel cell cathode produced by a method comprising the steps of:
(i) providing a primary layer comprising LSCF on a dense electrolyte layer;
(ii) isostatically pressing said primary layer in the pressure range 10-300 MPa;
(iii) providing on said pressed primary layer a current collecting layer comprising a perovskite-based electrode, to define a bi-layer cathode; and
(iv) firing said bi-layer cathode in a reducing atmosphere.
53 . A fuel cell cathode according to claim 52 , said primary layer having a thickness of about 0.5-20 μm.
54 . A fuel cell cathode according to claim 52 , said isostatic pressing being performed at a pressure of about 10-300 MPa.
55 . A fuel cell cathode according to claim 52 , said current collecting layer having a thickness of about 5-100 μm.
56 . A fuel cell cathode according to claim 52 , wherein said bi-layer cathode is fired at a temperature of about 700-900° C.
57 . A fuel cell cathode according to claim 52 , wherein said bi-layer cathode is re-oxidized after being fired in said reducing atmosphere.
58 . The method of claim 1 , wherein the current collecting layer is a non-isostatically pressed layer.
59 . The fuel cell cathode of claim 52 , wherein the current collecting layer is a non-isostatically pressed layer.