Stability enhancement of polymer electrolyte membrane fuel cells based on a sulfonated poly(ether ether ketone)/poly(vinylidene fluoride) composite membrane

Most proton-conducting membranes based on sulfonated aromatic polymers exhibit significant dimensional change by hydration, and this leads to degradation of fuel cell performance on prolonged operation. In this study, as a means of improving the stability of a polymer electrolyte membrane fuel cell, composite membranes employing a porous poly(vinylidene fluoride) (PVdF) substrate and sulfonated poly(ether ether ketone) (sPEEK) electrolyte are prepared and their hydration behaviours, including water uptake and dimensional change, are examined. The electrochemical characteristics of membrane/electrode assemblies using the sPEEK/PVdF composite membrane are also analyzed. The initial cell performance is comparable with that of a cell based on a pure sPEEK membrane. Furthermore, the stability of the cell using the sPEEK/PVdF composite membrane is considerably improved during a humidity cycle test wherein hydration and dehydration are periodically repeated. (C) 2010 Elsevier B.V. All rights reserved.