A study on fabrication of sulfonated poly(ether ether ketone)-based membrane-electrode assemblies for polymer electrolyte membrane fuel cells

Abstract

The porosity effect of catalyst electrodes in membrane-electrode assemblies (MEAs) using a hydrocarbon-based polymer as electrolyte and ionomer was investigated on physical and electrochemical properties by varying the content of ionomer binder (dry condition) in the catalyst electrodes. The MEAs were compared with the Nafion ®-based MEA using Nafion ® 112 and 5 wt.% ionomer solution (EW = 1100) in terms of porosity values, scanning electron microscopic images, Nyquist plots, dielectric spectra and I– V polarization curves. In this study, sulfonated poly(ether ether ketone) (SPEEK) membranes with 25 ± 5 μm of thickness and 5 wt.% ionomer solutions have been prepared. The prepared membranes were characterized in terms of FT-IR, DSC and proton conductivity. Proton conductivity of the SPEEK membranes was compared with one of the Nafion ® membranes with relative humidity. The porosity of the catalyst electrodes was calculated using the properties of catalyst, ionomer solution and solvent. As a result, the performance of the new type polymer (i.e., SPEEK in this study)-based MEA with the similar membrane conductivity and porosity of the catalyst electrode in the Nafion ® MEA was similar to that of the Nafion ® MEA.