Long-term durability of HT-PEM fuel cells based on thermally cross-linked polybenzimidazole

• Published in: Journal of power sources Vol. 342; pp. 570 - 578
• Main Authors: Søndergaard, Tonny, Cleemann, Lars Nilausen, Becker, Hans, Aili, David, Steenberg, Thomas, Hjuler, Hans Aage, Seerup, Larisa, Li, Qingfeng, Jensen, Jens Oluf
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 28.02.2017
• Subjects: Cross-linking; Durability; Fuel cell; Polybenzimidazole; Polymer electrolyte membrane; Thermally cured; Polymer electrolyte membrane; Durability; Polybenzimidazole; Cross-linking; Thermally cured; Fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2016.12.075

Long-term durability of high temperature polymer electrolyte membrane fuel cells based on thermally cross-linked polybenzimidazole membranes was studied and compared with reference membranes based on linear polybenzimidazole. The test was conducted at 160 °C under constant load currents of 200 mA cm−2 for periods of 1000, 4400, and 13,000 h. Extensive beginning-of-life (BoL) and end-of-test (EoT) characterisation was carried out, and disturbance of the steady state operated cells was minimised by limiting in-line diagnostics to the low-invasive technique of electrochemical impedance spectroscopy (EIS). Up until the operating time of 9200 h, the cell equipped with the cross-linked membrane showed an average degradation rate of 0.5 μV h−1, compared to 2.6 μV h−1 for the reference membrane, though parallel tests for a shorter period of time showed deviations, likely due to malfunctioning contact between layers or cell components. For the full test period of 13,000 h, the average voltage decay rate was about 1.4 and 4.6 μV h−1 for cells equipped with cross-linked and linear polybenzimidazole membranes, respectively. EIS and post-test analysis revealed that the cross-linked membrane showed better stability in terms of area specific resistance due to improved acid retention characteristics. [Display omitted] •High temperature PEMFC durability studied under steady state conditions for over 13,000 h.•Well defined beginning-of-life and end-of-test with minimal operational disturbance.•Lowest degradation rate of 0.5 μV h−1 within first 9200 h reported for cross-linked membranes.•Average voltage decay rate of about 1.4 μV h−1 with 13,000 h versus 4.6 μV h −1 for reference.•EIS and post mortem analysis showed improved acid retention of the cross-linked membrane.