Vehicle applications require efficient cold start ability and durability of polymer electrolyte membrane fuel cells (PEMFCs). In this study, various self-cold start strategies including purging the PEMFC at shutdown and using galvanostatic operation at startup are proposed. The cold start characteristics from −5 • C of a single cell are experimentally investigated in situ on a laboratory scale. The amount of cumulated charge transfer density, corresponding to the amount of product water, is used as an index to quantify the cold start capability. Gas purge at shutdown before freeze is found to facilitate the PEMFC cold start, although the improvement is relatively small compared with other methods such as gradually increasing the current during startup. Microscopic studies of the membrane electrode assembly (MEA) after cold start failure are conducted to determine material degradation due to ice formation.

Polymer stabilization proved to be a promising approach to increase the catalytic performance of common platinum/carbon based cathode catalysts (Pt/C) used in polymer electrolyte membrane fuel cells (PEMFCs). Platinum and polyaniline composite catalysts (Pt/C/PANI) were prepared by combining chemical polymerization reactions with anion exchange reactions. Electrochemical ex‐situ characterizations of the decorated Pt/C/PANI catalysts show high catalytic activity toward the oxygen reduction reaction (ORR) and, more importantly, a significant enhanced durability compared to the undecorated Pt/C catalyst. Transmission electron microscopy (TEM) investigations reveal structural benefits of Pt/C/PANI for ORR catalysis. All studies confirm high potential of Pt/C/PANI for practical fuel cell application.

This report was .prepared as an account of work sponsored by an agency of t h e United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes a n y legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by t h e United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of t h e United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products.. Images are produced from the best available original document.