1. Novel organic–inorganic composite polymer-electrolyte membranes for DMFCs
- Author
-
Ashok Kumar Shukla, N. Chandrakumar, V. Vimalan, Santoshkumar D. Bhat, Parthasarathi Sridhar, S. Pitchumani, Christy George, and Akhila Kumar Sahu
- Subjects
Proton conductivity ,synthesis ,Polymers ,Proton-exchange membrane ,Synthetic membrane ,Inorganic fillers ,Titanium castings ,Proton exchange membrane fuel cell ,electrolyte ,Inorganic precursor ,Biochemistry ,Nuclear magnetic resonance ,Polymerization ,Electrolytes ,chemistry.chemical_compound ,Direct methanol fuel cell ,Volume reductions ,General Materials Science ,Nafion composites ,Inorganic materials ,Titanium ,silicon dioxide ,Hydrolysis ,diffusion ,Mesoporous titanium phosphate ,Phosphorus ,Silica ,In-situ polymerization ,unclassified drug ,Membrane ,priority journal ,Zirconium phosphate ,Capillarity ,Nafion composite ,Point resolved spectroscopies ,direct methanol fuel cell ,Direct methanol fuel cells (DMFC) ,poloxamer ,Methanol permeability ,Titania sol ,Pluronics ,proton ,conductance ,Structure directing agents ,Materials science ,polymer ,water ,Inorganic chemistry ,Filtration and Separation ,Mesoporous ,Polymerization reaction ,artificial membrane ,NMR spectroscopy ,Methanol fuels ,zirconium oxide ,transmission electron microscopy ,Physical and Theoretical Chemistry ,Titanium isopropoxide ,In situ polymerization ,Nafion-silica composite ,Nuclear magnetic resonance spectroscopy ,Osmotic drag ,methanol ,Release kinetics ,copolymer ,Acidic nature ,titanium dioxide ,Composite membranes ,Titanium oxides ,mesoporous zirconium phosphate ,matrix ,Mesoporous materials ,Organic-inorganic composite ,energy resource ,tensile strength ,chemistry ,kinetics ,Iso-propoxide ,Sols ,Zirconia ,Zirconium ,measurement ,Mesoporous material - 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. � 2009 Elsevier B.V. All rights reserved.
- Published
- 2009