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Modified-Pore-Filled-PVDF-Membrane Electrolytes for Direct Methanol Fuel Cells

Alwin, S and Bhat, SD and Sahu, AK and Jalajakshi, A and Sridhar, P and Pitchumani, S and Shukla, AK (2011) Modified-Pore-Filled-PVDF-Membrane Electrolytes for Direct Methanol Fuel Cells. In: Journal of the Electrochemical Society, 158 (2). B91-B98.

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Abstract

The polyvinylidene fluoride (PVDF) membrane is modified by the chemical etchant-route employing a sodium naphthalene charge-transfer complex followed by impregnation with Nafion ionomer or polyvinyl alcohol (PVA)-polystyrene sulfonic acid (PSSA) polymeric blend solutions by a dip-coating technique to form pore-filled-membrane electrolytes for application in direct methanol fuel cells (DMFCs). The number of coatings on the surface-modified PVDF membrane is varied between 5 and 15 and is found to be optimum at 10 layers both for Nafion and PVA-PSSA impregnations for effective DMFC performance. Hydrophilicity of the modified-membrane electrolytes is studied by determining average contact angle and surface-wetting energy. Morphology of the membranes is analyzed by a cross-sectional scanning electron microscope. The modified PVDF membrane electrolytes are characterized for their water-methanol sorption in conjunction with their mechanical properties, proton conductivity, and DMFC performance. Air permeability for the modified membranes is studied by a capillary-flow porometer. Methanol crossover flux across modified-PVDF-membrane electrolytes is studied by measuring the mass balance of methanol using a density meter. DMFCs employing membrane electrode assemblies with the modified PVDF membranes exhibit a peak power-density of 83 mW/cm(2) with Nafion impregnation and 59 mW/cm(2) for PVA-PSSA impregnation, respectively. Among the membranes studied here, stabilities of modified-pore-filled PVDF-Nafion and PVDF-PVA-PSSA membranes with 10-layers coat are promising for application in DMFCs. (C) 2010 The Electrochemical Society. DOI: 10.1149/1.3518774] All rights reserved.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to The Electrochemical Society.
Keywords: charge exchange; contact angle, dip coating; direct methanol fuel cells, hydrophilicity; ionic conductivity; membranes; permeability; polymer blends; polymer electrolytes; polymer solutions; proton exchange membrane fuel cells; scanning electron microscopy; sorption; wetting
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited: 08 Mar 2011 06:37
Last Modified: 08 Mar 2011 06:37
URI: http://eprints.iisc.ernet.in/id/eprint/35891

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