LOW-COST ELECTRODES FOR PROTON-EXCHANGE MEMBRANE FUEL-CELLS - PERFORMANCE IN SINGLE CELLS AND BALLARD STACKS

For widespread exploitation of proton exchange membrane fuel cells (PE MFCs) the cost of the stack must be reduced, and the performance per u nit volume increased. Significant cost reduction has been achieved by the development of a high-volume, low cost, electrode manufacturing pr ocess and from reductions in the electrode precious metal catalyst loa dings. The performance of membrane electrode assemblies (MEAs) employi ng printed cathodes (less than or equal to 0.6 mg Pt/cm(2)) and anodes (less than or equal to 0.25 mg Pt/cm(2) 0.12 mg Ru/cm(2)) in Ballard Mark V single-cell and advanced-stack hardware are at least comparable to current stack MEAs comprising high loading unsupported platinum bl ack electrodes containing 4.0 mg Pt/cm(2). Optimum cell performance ha s provided high power densities of 0.42 W/cm(2) at 0.7 V. Furthermore, under motive and utility test conditions, the low-cost electrodes sho w minimal loss in performance after over 3000 h of stack operation and , in short and full sized stacks, the cell-to-cell reproducibility is excellent, highlighting the high consistency of product available from the electrode manufacturing process. Incorporation of the low cost el ectrodes in commercial PEMFC stacks is anticipated in the near future.