Open AccessEffects of PEMFC Operational History under Dry/Wet Conditions on Additional Voltage Losses due to Ionomer Migration
Author(s) -
Fengmin Du,
Tuấn Anh Đào,
Pia Valentina Josephine Peitl,
Andreas Bauer,
Kathrin Preuß,
Alex Martinez Bonastre,
Jonathan Sharman,
Geoffrey H. Spikes,
Markus Perchthaler,
Thomas J. Schmidt,
Alin Orfanidi
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abc83f
Subject(s) - ionomer , electrolyte , proton exchange membrane fuel cell , polymer , degradation (telecommunications) , chemical engineering , materials science , dry gas , scanning electron microscope , membrane , cathode , conductivity , composite material , catalysis , chemistry , fuel cells , chromatography , electrical engineering , electrode , biochemistry , engineering , copolymer
Over its lifetime in a fuel cell electric vehicle, a polymer electrolyte membrane fuel cell inevitably suffers from certain duration of dry operational conditions, where significant performance losses of the fuel cell take place. In this study, we investigate the activity changes of the fuel cell after a prolonged degradation protocol under dry operational condition, followed by various recovery procedures under wet conditions. The utilization of diluted air on the cathode side is found to be advantageous for the recovery due to the superior heat and water management. This more efficient recovery protocol allows the deconvolution of reversible and irreversible voltages losses after dry operations. A subsequent mechanistic study reveals an irreversible decrease of the effective ionomer coverage on the catalyst particles, while the proton conductivity of the catalyst layer drops. These observations point towards ionomer structural changes caused by the dry conditions. This is confirmed by post-mortem analysis via scanning electron microscope, showing clearly that ionomer redistributes and migrates, an additional mechanism which leads to the performance losses. Overall, the degradation mechanisms seem to be mitigated by higher ionomer content in the catalyst layer, while the investigated surface modification of carbon support shows minor sensitivities.