Methods of making components for electrochemical cells
View Patent ↗The present invention is related to methods of making membrane electrode assembly components. The methods include transferring a catalyst layer to a polymer electrolyte membrane or a gas diffusion layer. Methods of making membrane electrode assemblies with these components are also disclosed.
1. A method of making a component for an electrochemical fuel cell comprising:
forming a diffusion sublayer on a surface of a release sheet;
forming a catalyst layer comprising a catalytic material on the diffusion sublayer;
transferring the catalyst layer to a surface of a solid polymer electrolyte membrane;
removing the release sheet from the diffusion sublayer; and
bonding a first gas diffusion substrate to the diffusion sublayer following removal of the release sheet.
2. The method of claim 1 , wherein the diffusion sublayer comprises a carbon material, a graphitic material, or combinations thereof.
3. The method of claim 1 , wherein transferring comprises subjecting the catalyst layer and the solid polymer electrolyte membrane to at least one of heat and pressure.
4. The method of claim 1 , wherein the catalyst layer further comprises an ionomer.
5. The method of claim 1 , further comprising bonding a gas diffusion electrode against an opposing surface of the solid polymer electrolyte membrane, the gas diffusion electrode comprising a second gas diffusion substrate, a second catalyst layer, and a second diffusion sublayer interposed therebetween, such that the second catalyst layer contacts the opposing surface of the solid polymer electrolyte membrane, to form a membrane electrode assembly.
6. A method of making a component for an electrochemical fuel cell comprising:
forming a catalyst layer comprising a catalytic material on a surface of a release sheet;
forming a first diffusion sublayer on a surface of the catalyst layer;
forming a second diffusion sublayer on a surface of a gas diffusion substrate;
bonding the first diffusion sublayer to the second diffusion sublayer;
removing the release sheet from the catalyst layer to form a gas diffusion electrode; and
contacting the gas diffusion electrode against a first surface of a solid polymer electrolyte membrane such that the catalyst layer faces the first surface.
7. The method of claim 6 , wherein the catalyst layer and the first diffusion sublayer further comprise a hydrophobic binder, and the method further comprises heating the first diffusion sublayer and the catalyst layer to a sintering temperature of at least 250° C.
8. The method of claim 6 , wherein the second diffusion sublayer comprises a hydrophobic binder, and the method further comprises heating the second diffusion sublayer to a sintering temperature of at least 250° C.
9. The method of claim 6 , wherein the first and second diffusion sublayers comprise a carbon material, graphitic material, or combinations thereof.
10. The method of claim 6 , wherein the first and second diffusion sublayers are the same.
11. The method of claim 6 , further comprising removing a liquid carrier of at least one of the first and second diffusion sublayers during bonding.
12. The method of claim 6 , further comprising:
contacting a second gas diffusion electrode against an opposing second surface of the solid polymer electrolyte membrane; and
bonding the gas diffusion electrodes to the solid polymer electrolyte membrane.