■ Title : Performance improvements in High-Temperature PEM Fuel Cells
■ Speaker : Dr. Hans Aage Hiuler (Danish Power System)
■ Invitation from : Prof. EunAe Cho (T. 3317)
■ Date and time : 13th of November, (Mon) 16:50
■ Venue : Applied Engineering Dpt. Bd W1 Room 2425
■ Abstract :
The work presented here focuses on recent results obtained on degradation of PBI membranes used in membrane electrode assemblies (MEAs) for high temperature polymer electrolyte fuel cells (HTPEM) that operates in the temperature range 140-180 °C. The testing is done at 160 °C using either pure hydrogen or reformate of different compositions /1/.
Pure platinum versus PtCo alloys have been studied. The latest developments show that it is possible to reduce the Pt loading, increase the platinum utilization and achieve a long lifetime. We have shown that cells based on a thermally cured membrane proved a degradation rate of as little as 0.5 μV/h over an extended period of time /2/. This is, to the authors’ knowledge, lower than what is ever reported for HTPEM.
The degradation mechanisms over time have been studied using SEM and TEM characterization tools. It has been shown that the Pt nanocatalyst particles grow from approx. 3 to 9 nm over 17,000 hours on the cathode side, while the anode is far less affected.
The durability of HTPEM can now be considered similar to low temperature PEM. We have demonstrated more than 15,000 hours in single cells at 0.3 A/cm2. The degradation rate is around 4 μV/h for approx. 13,000 hours.
The high operating temperature makes it possible to make commercial fuel cell systems using methanol (methanol-water mixtures) as fuel. The HTPEM cells can tolerate CO impurities up to more than 3 vol-% without significant losses. Several demonstration projects have been made, including a Fiat 500 equipped with a 5 kW methanol based fuel cell system. This car is in every day operation at a catering company in Denmark.
/1/ Jens Oluf Jensen, David Aili, Hans Aage Hjuler, Qingfeng Li, High Temperature Polymer Electrolyte Membrane Fuel Cells - Approaches, Status and Perspective, eds. Q. Li, D Aili, H. A. Hjuler and J. O. Jensen, ISBN 978-3-319-17081-7; DOI 10.1007/978-3-319-17082-4, Springer International Publishing, New York, 2015.
/2/ Mark Tonny Dalsgaard Jakobsen, Lars Nilausen Cleemann, Hans Becker, David Aili, Thomas Steenberg, Hans Aage Hjuler, Larisa Seerup, Qingfeng Li, Jens Oluf Jensen, J. Power Sources, 342 (2017) 570-578.