Proton exchange membrane materials for the advancement of direct methanol fuel-cell technology
US7022810B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 2003 |
| Grant date | Apr 4, 2006 |
| Priority date | — |
| Expiry date | Dec 18, 2023 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G73/1064
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion® PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5–5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O2 and H2 gas permeability, while retaining proton conductivities similar to Nafion®. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.