NEW PREPARATION METHOD FOR POLYMER-ELECTROLYTE FUEL-CELLS

A new preparation method for the catalyst layer in the electrodes of a polymer electrolyte fuel cell, based on the process of preparing perf luorosulfonate-ionomer (PFSI) colloid, was developed. In this method, both a good network of PFSI and uniformity of PFSIs on Pt particles we re achieved with colloid formation of PFSI chains in the specific orga nic solvents. The applicable organic solvents had dielectric constants ranging from 3 to 10. The PFSI colloids were selectively adsorbed ont o the carbon agglomerates with highly dispersed Pt particles on the su rface, and a catalyst paste-formation followed. Then the catalyst past e was spread over a carbon paper representing the gas diffusion layer, and two sheets of carbon paper with catalyst paste on them were hot p ressed onto an ion-exchange membrane from both sides. This simple prep aration method provided high performance in fuel cells at low temperat ure (50 degrees C).