Method of making membrane electrode assemblies
View Patent ↗A method of making a membrane electrode assembly is provided. The method includes providing a non-porous substrate which has sufficient structural integrity to be reusable or which is formed into a loop. A slurry is formed which includes an ionically conductive material, an electrically conductive material, a catalyst, and a solvent. The slurry is applied onto the non-porous substrate, for example, in a pattern of discrete areas. The slurry is dried to form decals. The decals are bonded to a membrane and then the substrate is peeled from the decal in a substantially undamaged condition so that it may be reused.
1. A method useful for making a membrane electrode assembly comprising:
providing a non-porous substrate comprising a metallic film that is laminated to another film material which provides additional structural integrity, which substrate has sufficient structural integrity to be reusable;
forming a slurry including an ionically conductive material, an electrically conductive material, a catalyst, and a solvent;
applying the slurry onto the non-porous substrate;
drying the applied slurry to form a first decal;
bonding the first decal to a membrane;
peeling the non-porous substrate from the first decal in a substantially undamaged condition; and
reusing the non-porous substrate by applying the slurry onto the nonporous substrate, drying the applied slurry to form a second decal; bonding the second decal to a membrane and peeling the non-porous substrate from the second decal.
2. A method according to claim 1 further comprising the step of cleaning the non-porous substrate prior to the step of reusing.
3. A method according to claim 2 wherein the cleaning step further comprise applying to the non-porous substrate a solvent selected from the group consisting of iso and normal propanol, ethanol, methanol, water, and mixtures thereof.
4. A method according to claim 1 wherein the drying steps include subjecting the slurry to infrared lamps.
5. A method according to claim 1 wherein the applying steps include a coating process selected from the group consisting of a printing and a spraying processes.
6. A method according to claim 1 wherein the ionically conductive material comprises an ionomer and the bonding steps further comprise hot-pressing at or above the glass transition temperature of the ionomer.
7. A method according to claim 1 wherein the electrically conductive material is carbon and the catalyst is a metal.
8. A method according to claim 1 wherein the ionically conductive material is a perfluorosulfonate ionomer.
9. A method of making membrane electrode assemblies comprising:
providing a loop of a non-porous substrate comprising a metallic film that is laminated to another film material which provides additional structural integrity;
forming a slurry comprising an ionically conductive material, an electrically conductive material, a catalyst, and a solvent;
applying the slurry to the non-porous substrate in a pattern of discrete areas;
drying the slurry to form a first plurality of decals corresponding to the discrete areas on the non-porous substrate;
bonding the decals to opposite sides of a first plurality of membranes to form a first plurality of membrane electrode assemblies,
peeling the first plurality of membrane electrode assemblies from the loop of non-porous substrate;
cleaning the non-porous substrate;
re-applying the slurry to the cleaned loop of non-porous substrate;
drying the re-applied slurry to form a second plurality of decals;
bonding the second plurality of decals to a second plurality of membranes to form a second plurality of membrane electrode assemblies; and
peeling the second plurality of membrane electrode assemblies from the loop of non-porous substrate.
10. A method according to claim 9 wherein the cleaning step further comprises applying to the non-porous substrate a solvent selected from the group consisting of iso and normal propanol, ethanol, methanol, water, and mixtures thereof.
11. A method according to claim 9 wherein bonding the decals to opposite sides occurs simultaneously.
12. A method according to claim 9 wherein the loop of non-porous substrate has sufficient structural integrity to be reused.
13. A method according to claim 9 further comprising continuously moving the loop of non-porous substrate.
14. A method according to claim 9 wherein the applying steps comprise a coating process selected from the group consisting of printing and spraying processes.
15. A method according to claim 9 wherein the ionically conductive material comprises an ionomer and the bonding steps further comprise hot-pressing at or above the glass transition temperature of the ionomer.
16. A method according to claim 9 wherein the electrically conductive material is carbon and the catalyst is a metal.
17. A method according to claim 9 wherein the ionically conductive material is a perfluorosulfonate ionomer.
18. A method useful for making a membrane electrode assembly comprising:
providing a non-porous substrate which has sufficient structural integrity to be reusable;
forming a slurry including an ionically conductive material, an electrically conductive material, a catalyst, and a solvent;
applying the slurry onto the non-porous substrate;
drying the applied slurry to form a decal;
bonding the decal to a membrane; and
peeling the substrate from the decal in a substantially undamaged condition so that it may be reused;
wherein the non-porous substrate comprises a metallic film and the metallic film is provided by laminating the metallic film to another film material which provides at least some of the structural integrity of the nonporous substrate.