Aqueous ionomeric gels and products and methods related thereto
View Patent ↗An aqueous ionomer gel having a high viscosity, particularly a proton conducting ionomer, as well as to related products incorporating such gels. Such aqueous ionomer gels are suitable for suspending catalysts for formation of catalyst inks, which in turn are suitable for screen printing on a variety of surfaces. Representative surfaces are the electrode or membrane surfaces in an electrochemical fuel cell. Methods for making aqueous ionomer gels are also disclosed.
1. A catalyst ink comprising an aqueous ionomer gel and a catalyst, wherein the aqueous ionomer gel is with organic solvent contaminants at a concentration below 4% by volume, having an ionomer solids content ranging from about 4% to about 18% by weight of the gel and a viscosity in excess of 5,000 centipoise at a shear rate of 10 second −1 .
2. The catalyst ink of claim 1 wherein the catalyst is a noble metal catalyst.
3. The catalyst ink of claim 2 wherein the noble metal is platinum.
4. The catalyst ink of claim 1 having a catalyst solids contend ranging from about 4 to about 40% by weight of the catalyst ink.
5. The catalyst ink of claim 1 having a catalyst solids contend ranging from about 20 to about 40% by weight of the catalyst ink.
6. The catalyst ink of claim 1 further comprising a filler, binder, pore forming material or combination thereof.
7. A coated substrate, wherein the substrate has at least one surface coated with the catalyst ink of claim 1 .
8. The coated substrate of claim 7 wherein the substrate is an electrode.
9. The coated substrate of claim 8 wherein the electrode is an electrochemical fuel cell electrode.
10. An electrochemical fuel cell comprising a coated surface of claim 7 .
11. A membrane comprising the catalyst ink of claim 1 .