| US 7,517,604 B2 | ||
| Fuel cell electrolyte membrane with acidic polymer | ||
| Steven J. Hamrock, Stillwater, Minn. (US); James M. Larson, Saint Paul, Minn. (US); Phat T. Pham, Little Canada, Minn. (US); Matthew H. Frey, Cottage Grove, Minn. (US); Gregory M. Haugen, Edina, Minn. (US); and William M. Lamanna, Stillwater, Minn. (US) | ||
| Assigned to 3M Innovative Properties Company, Saint Paul, Minn. (US) | ||
| Filed on Sep. 19, 2005, as Appl. No. 11/230,090. | ||
| Prior Publication US 2007/0243446 A1, Oct. 18, 2007 | ||
| Int. Cl. H01M 8/10 (2006.01) | ||
| U.S. Cl. 429—33 [429/12; 429/30; 429/42; 429/309; 521/27] | 18 Claims |
| 1. An electrolyte membrane comprising:
an acidic polymer; and
a fluorinated acid that is substantially free of basic groups, wherein the fluorinated acid contains 20 acid-functional groups
or less per molecule and has a molecular weight of less than 10,000, and wherein, after being heated from 1° C. to 200° C.
at a ramp rate of 10° C./minute, and then cooled to 120° C. within 5 minutes, the fluorinated acid exhibits a cumulative mass
loss of about 6% or less, based on an initial weight of the fluorinated acid, while being maintained at 120° C. for a 24 hour
period, the cumulative mass loss being measured during the 24 hour period, and wherein the electrolyte membrane contains less
than about 60% by weight phosphoric acid.
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