Fuel cell and method for reducing electrode degradation during startup and shutdown cycles
AssigneeGM Global Technology Operations LLC
InventorsSwathy Swathirajan, Belabbes Merzougui, Paul Taichiang Yu
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Abstract
One embodiment of the invention includes a product comprising: a membrane electrolyte having a first face and a second face; and an anode over the first face and a cathode over the second face, and wherein the anode has a catalyst loading that is less than 50% of the catalyst loading of the cathode.
Claims20
A product comprising:
- an anode comprising a first carbon support and a first catalyst;
- said first catalyst loading being 0.07 mg/cm2 or less;
- said first carbon support having a BET surface area of less than about 200 m2/g, and said anode having a thickness less than about 10 μm;
- a cathode comprising a second carbon support and a second catalyst;
- said cathode being at least twice as thick as the anode is;
- said second metal catalyst loading being at least 0.15 mg/cm2;
- and
- a membrane electrolyte having a first side and a second side;
- wherein said anode is intimately attached to the first side of said membrane electrolyte and said cathode is intimately attached to the second side of said membrane electrolyte.
A product comprising a membrane electrode assembly comprising an anode comprising a catalyst at total loading level of about 0.01 to about 0.07 mg/cm2 and a first support having a BET surface area of less than about 200 m2/g.
A product comprising:
- a membrane electrolyte having a first face and a second face;
- and an anode comprising a catalyst over the first face and a cathode comprising a catalyst over the second face, and wherein the anode has a catalyst loading that is less than 50% of the catalyst loading of the cathode.
A product comprising:
- a polyelectrolyte membrane having a first face and a second face, and an anode over the first face and a cathode over the second face, the anode comprising a first catalyst and the cathode comprising a second catalyst and the anode having a catalyst loading ranging from about 0.002 to about 0.1 mg/cm2, and the cathode having a catalyst loading ranging from about 0.1 to about 0.3 mg/cm2, and wherein the anode catalyst loading is less than 50% of the cathode catalyst loading, and wherein the anode has a thickness ranging from about 1 to about 10 μm and the cathode has a thickness ranging about 10 μm to about 15 μm.
A method of starting up a fuel cell comprising:
- providing a fuel cell comprising a membrane electrolyte having a first side, a second side, and a thickness;
- an anode over the first side of said membrane, a cathode over the second side of said membrane, an anode gas flow field and a cathode gas flow field, an oxidant gas residing in the flow fields of both the anode and the cathode;
- wherein said anode has a thickness of less than about 10 μm and said cathode is at least twice as thick as said anode;
- connecting said fuel cell anode to a fuel gas supply;
- rapidly flowing a fuel gas through the flow field of said anode to substantially replace said oxidant gas such that the potential shift on cathode during such gas change is no more than about 0.1V;
- connecting said fuel cell cathode to an oxidant gas supply;
- and
- connecting said fuel cell to an external load.
A method of shutting down a fuel cell comprising:
- providing a fuel cell comprising a membrane electrolyte, having a first side, a second side, and a thickness;
- an anode attached to the first side of said membrane, a cathode attached to the second side of said membrane, an oxidant gas flowing over the surfaces of said cathode through a defined cathode flow field and a fuel gas flowing over the surface of said anode in a defined anode flow field;
- wherein said anode has a thickness of less than about 10 μm and said cathode is at least twice as thick as said anode;
- disconnecting the fuel gas supply;
- and
- rapidly flowing said oxidant gas to the flow field of said anode to substantially replace said fuel gas such that the potential shift on cathode during such gas change is no more than about 0.26V.
Dependencies are inferred from the claim text.