Patterning Catalyst Layers with Microscale Features by Soft Lithography Techniques for Proton Exchange Membrane Fuel Cells

Microtransfer molding (µTM) and microcontact printing (µCP) techniques were demonstrated for the preparation of platinum based catalysts in hexagonally arranged patterns to achieve cathode catalyst layers (CCLs) with microscale patterned features. These soft lithographic techniques, previously demonstrated for use in the preparation of patterned thin films, were adopted to produce patterned CCLs for proton exchange membrane fuel cells (or PEMFCs) with features having a thickness up to 20 µm. The resulting CCLs contained precise microscopic patterns that could be tuned for improving the performance of PEMFCs. It was demonstrated that CCLs containing arrays of microscale, cylindrical holes as prepared by µTM exhibited an improvement in their water management characteristics within PEMFCs when compared to CCLs prepared from continuous catalyst films. Upon further tuning of the CCL transfer procedures for µCP of CCLs, the formation of isolated microscale, disc-like features were demonstrated to have twice the...