FUEL 58 |
| Phosphoric acid doped polybenzimidazoles have been reported to be promising candidates for high temperature PEMFCs, having good proton conductivity, low gas permeability, and excellent thermal stability. A high molecular weight, thermally stable, fluorine-containing polybenzimidazole (6F-PBI) was synthesized from 3,3',4,4'-tetraaminobiphenyl and 4,4'-(perfluoropropane-2,2-diyl)dibenzoic acid in polyphosphoric acid (PPA) as both the polycondensation agent and the polymerization solvent. The optimization of polymerization conditions to achieve the high molecular weight polymers was explored via the stepwise heating profile. Highly PA doped 6F-PBI membranes were formed with the "sol-gel" process during PPA hydrolysis to PA. These PBI membranes showed higher mechanical properties and proton conductivity than the PBI membranes from the conventional imbibing method. Preliminary experiments showed the feasibility of PA doped 6F-PBI membranes as polymer electrolyte membranes for high temperature PEMFC applications, obtaining a maximum power output of 0.43 W/cm2 at 160¢ªC with dry hydrogen/oxygen. |
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Green Chemistry for Sustainable Energy Supply and Conversion
8:15 AM-12:15 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 242, Oral
Sci-Mix
Division of Fuel Chemistry |