Journal article
Hybrid materials for polymer electrolyte membrane fuel cells: Water uptake, mechanical and transport properties
Dip. Scienze e Tecnologie Chimiche, Università di Roma “Tor Vergata”, 00133 Roma, Italy1
MADIREL, Université de Provence-CNRS (UMR 6121), Centre St Jérome, 13397 Marseille Cedex 20, France2
The water uptake, transport and mechanical properties of organic–inorganic hybrid materials based on sulfonated and silylated, cross-linked polyetheretherketone (called SOSi-PEEK/N, where N is the molar percentage of silylated monomeric units) for application in fuel cells are reported. The mechanical properties are superior to those of S-PEEK, due to the presence of silicon.
The water and proton diffusion coefficients are reported as function of temperature and relative humidity. The proton conductivity of the membranes increases nearly four orders of magnitude when relative humidity varies from 30% to 100% corresponding to an increase of water/equivalent of ion-exchange groups, λ, from 1 to 15.
The activation energy for proton conduction is slightly higher than in Nafion. Proton diffusion coefficients obtained from the Nernst–Einstein equation are compared with water chemical diffusion coefficients determined from water sorption kinetics. The equivalence of both quantities for λ≥4 indicates that proton conductivity takes place via Grotthuss-type mechanism.
Language: | English |
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Year: | 2007 |
Pages: | 76-81 |
ISSN: | 18733123 and 03767388 |
Types: | Journal article |
DOI: | 10.1016/j.memsci.2007.07.013 |