Sulfonated polyether ether ketone-based composite membranes doped with a tungsten-based inorganic proton conductor for fuel cell applications

Sulfonated polyether ether ketone (SPEEK)-based composite membranes doped with hydrated tungsten oxide were prepared and studied for proton exchange membrane applications. Hydrated tungsten oxide (W O3 ·2 H2 O) was synthesized via acidic hydrolysis of sodium tungstate and its structure and physicochemical features were investigated by thermogravimetric analysis (TG), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). SPEEK/ W O3 ·2 H2 O composite membranes were prepared by mixing proper amounts of SPEEK and hydrated W O3 in dimethylacetamide as casting solvent. The composite membranes were characterized by XRD, TG-DTA, EIS, and water uptake measurements as a function of the oxide content in the membrane. In particular, XRD patterns as well as TG measurements indicated the existence of a coordinative interaction between the water molecules of tungsten oxide and the SPEEK sulfonic acid groups. This interaction lead to the enhancement of the membrane proton conductivity, as well as of their properties, from the point of view of heat resistance and water solubility. In fact, the addition of tungsten oxide resulted in higher proton conductivity, improved heat resistance, and lower water solubility. © 2006 The Electrochemical Society. All rights reserved.

[1]  P. Barboux,et al.  Protonic conductivity in hydrates , 1988 .

[2]  S. Srinivasan,et al.  Composite Nafion/Zirconium Phosphate Membranes for Direct Methanol Fuel Cell Operation at High Temperature , 2001 .

[3]  S. Licoccia,et al.  A covalent organic/inorganic hybrid proton exchange polymeric membrane: synthesis and characterization , 2005 .

[4]  T. Kudo,et al.  Proton conductivity of tungsten trioxide hydrates at intermediate temperature , 2000 .

[5]  S. Kaliaguine,et al.  Sulfonated polyether ether ketone based composite polymer electrolyte membranes , 2001 .

[6]  Michael D. Guiver,et al.  Proton conducting composite membranes from polyether ether ketone and heteropolyacids for fuel cell applications , 2000 .

[7]  N. Berezina,et al.  A Comparative Study of the Electric Transport of Ions and Water in Sulfonated Cation-Exchange Polymeric Membranes of the New Generation , 2003 .

[8]  G. Alberti,et al.  New Preparation Methods for Composite Membranes for Medium Temperature Fuel Cells Based on Precursor Solutions of Insoluble Inorganic Compounds , 2005 .

[9]  C. Wieser,et al.  Novel Polymer Electrolyte Membranes for Automotive Applications – Requirements and Benefits , 2004 .

[10]  A. Kornyshev,et al.  Proton transfer in a single pore of a polymer electrolyte membrane , 2001 .

[11]  D. Wiles,et al.  The thermal degradation of poly(aryl—ether—ether—ketone) (PEEK) as monitored by pyrolysis—GC/MS and TG/MS☆ , 1990 .

[12]  N. Mizuno,et al.  Proton conductive amorphous thin films of tungsten oxide clusters with acidic ligands , 1997 .

[13]  G. Robertson,et al.  Casting solvent interactions with sulfonated poly(ether ether ketone) during proton exchange membrane fabrication , 2003 .

[14]  M. L. Freedman.  The Tungstic Acids , 1959 .

[15]  Vijay Ramani,et al.  Stabilized heteropolyacid/Nafion® composite membranes for elevated temperature/low relative humidity PEFC operation , 2005 .

[16]  L. Klein,et al.  Transport properties of Nafion™ composite membranes for proton-exchange membranes fuel cells , 2003 .

[17]  S. Licoccia,et al.  Composite Mesoporous Titania Nafion-Based Membranes for Direct Methanol Fuel Cell Operation at High Temperature , 2005 .