Novel organic-inorganic composite polymer-electrolyte membranes for DMFCs

Sahu, A. K. ; Bhat, S. D. ; Pitchumani, S. ; Sridhar, P. ; Vimalan, V. ; George, C. ; Chandrakumar, N. ; Shukla, A. K. (2009) Novel organic-inorganic composite polymer-electrolyte membranes for DMFCs Journal of Membrane Science, 345 (1-2). pp. 305-314. ISSN 0376-7388

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S03767...

Related URL: http://dx.doi.org/10.1016/j.memsci.2009.09.016

Abstract

Organic-inorganic composite membranes comprising Nafion with inorganic materials such as silica, mesoporous zirconium phosphate (MZP) and mesoporous titanium phosphate (MTP) are fabricated and evaluated as proton-exchange-membrane electrolytes for direct methanol fuel cells (DMFCs). For Nafion-silica composite membrane, silica is impregnated into Nafion matrix as a sol by a novel water hydrolysis process precluding the external use of an acid. Instead, the acidic nature of Nafion facilitates in situ polymerization reaction with Nafion leading to a uniform composite membrane. The rapid hydrolysis and polymerization reaction while preparing zirconia and titania sols leads to uncontrolled thickness and volume reduction in the composite membranes, and hence is not conducive for casting membranes. Nafion-MZP and Nafion-MTP composite membranes are prepared by mixing pre-formed porous MZP and MTP with Nafion matrix. MZP and MTP are synthesised by co-assembly of a tri-block co-polymer, namely pluronic-F127, as a structure-directing agent, and a mixture of zirconium butoxide/titanium isopropoxide and phosphorous trichloride as inorganic precursors. Methanol release kinetics is studied by volume-localized NMR spectroscopy (employing "point resolved spectroscopy", PRESS), the results clearly demonstrating that the incorporation of inorganic fillers in Nafion retards the methanol release kinetics under osmotic drag. Appreciable proton conductivity with reduced methanol permeability across the composite membranes leads to improved performance of DMFCs in relation to commercially available Nafion-117 membrane.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Dmfc; Methanol Permeability; Nafion Composites; NMR Spectroscopy; Proton Conductivity
ID Code:5438
Deposited On:18 Oct 2010 09:42
Last Modified:17 Jul 2012 08:31

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