Effect of the catalytic ink preparation method on the performance of polymer electrolyte membrane fuel cells

The effect of the preparation method of the catalytic inks on the electrode structure and, thus, on the performance of polymer electrolyte membrane fuel cells (PEMFCs) was investigated. Since the catalytic inks, which are a mixture of Pt/C powders, solvent, and ionomers, change into one of the three states: (i) solution; (ii) colloids and (iii) precipitates, according to the interaction between the ionomers and solvents, two different catalytic inks, have been prepared for comparison, the solution inks based on iso-propyl alcohol (IPA) and the colloidal inks based on normal butyl acetate. Performance evaluation, electrochemical analyses, and physical property examination revealed that the electrode prepared by a colloidal method showed better results compared to those of the solution method. The former appeared to secure continuity of the ionomer network and higher porosity in the catalytic layer, resulting in higher proton conductivity and less mass transfer resistance. (C) 2002 Elsevier Science B.V. All rights reserved.