Stop-Start and High-Current Durability Testing of Nanostructured Thin Film Catalysts for PEM Fuel Cells

Abstract

This paper reports two new PEM fuel cell catalyst durability test results using 3M's nanostructured thin film (NSTF) catalysts, which do not use carbon-supports or additional ionomer in the electrode layer. One test uses an automotive start/stop (S/S) testing protocol provided through communication with Nissan, and compares the NSTF catalyst durability with that of a conventional carbon supported dispersed Pt catalyst. Fuel cell performance, cyclic voltammograms, surface area changes, specific activity and XRD crystallite sizes were measured before and after S/S testing. The NSTF catalyst show much less loss of performance under the S/S cycling and most of the loss is recoverable. The second test involves high current density operation under totally dry H2/O2 conditions. Operating with an average current density of 1 A/cm2, with over 1600 scans between 0.1 and 2 A/cm2, the NSTF MEA lasted 1000 hours, consistent with extremely low measured fluoride ion emission rates.