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Effects of Humidification on the Membrane Electrode Assembly of Proton Exchange Membrane Fuel Cells at Relatively High Cell Temperatures
Author(s) -
Yin K.M.,
Chang C.P.
Publication year - 2011
Publication title -
fuel cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.485
H-Index - 69
eISSN - 1615-6854
pISSN - 1615-6846
DOI - 10.1002/fuce.201100041
Subject(s) - proton exchange membrane fuel cell , dielectric spectroscopy , electrolyte , cathode , polarization (electrochemistry) , membrane , chemical engineering , analytical chemistry (journal) , chemistry , electrode , membrane electrode assembly , diffusion , diffusion layer , electrochemistry , materials science , nernst equation , chromatography , thermodynamics , biochemistry , physics , engineering
This study focuses on the performances of proton exchange membrane fuel cells (PEMFCs) at 80 and 90 °C with feeds of varying degrees of humidification. The results show that ohmic resistance of the solid electrolyte decreases as the current density is raised because of the back diffusion of liquid water, that is, generated in the cathode active layer. On the other hand, severe liquid water accumulation occurs at high current densities, which hinders the oxygen transport in the cathode gas diffusion layer (GDL) resulting in the Nernst diffusion limitation. The polarization measurement correlates well with the electrochemical impedance spectroscopy (EIS) analysis. The effects of humidification on membrane hydration, activity in the catalyst layer, and oxygen diffusion over‐potential in the cathode GDL are elucidated with the proposed equivalent circuit model at varying operating current densities.