Electro-osmotic drag of water in ionomeric membranes. New measurements employing a direct methanol fuel cell
- Los Alamos National Lab., NM (United States)
A direct methanol fuel cell (DMFC) employing a proton conducting membrane was used to determine the electro-osmotic drag coefficient of water in the ionomeric membrane. Water flux across the membrane in such a cell (operated with 1.0 M aqueous methanol at the anode and dry O{sub 2} at the cathode) is driven by protonic drag exclusively at sufficiently high current densities. This is evidenced experimentally by a linear relationship between cell current and flux of water measured crossing the membrane. Application of the DMFC for such water-drag measurements is significantly simpler experimentally than the approach described by the authors before, particularly so for measurements above room temperature. In measurements the authors performed in the DMFC configuration on Nafion 117 membranes, the water drag coefficient was found to increase with temperature, from 2.0 H{sub 2}O/H{sup +} at 15 C to 5.1 H{sub 2}O/H{sup +} at 130 C. Implications of these new results on water management in DMFCs are briefly discussed.
- Sponsoring Organization:
- Defense Advanced Research Projects Agency, Arlington, VA (United States); USDOE, Washington, DC (United States)
- OSTI ID:
- 556806
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 9 Vol. 144; ISSN JESOAN; ISSN 0013-4651
- Country of Publication:
- United States
- Language:
- English
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