Comparison of the performance and EIS (electrochemical impedance spectroscopy) response of an activated PEMFC (proton exchange membrane fuel cell) under low and high thermal and pressure stresses

In this study, it was demonstrated that membrane electrode assembly (MEA) conditioning at the low stress condition produces a higher performance compared to MEA conditioning under the high stress condition, although it needs more time to accomplish. The maximum power density (MPD) of 1600 mW cm⁻² was achieved by the MEA activated at low temperature and pressure (MEA-LTP) compared to the MEA activated at high temperature and pressure (MEA-HTP) in the same operating conditions, 1090 mW cm⁻², whiles the MEA structure of both cells was identical. MEA conditioning at the low stress condition enhances not only the fuel cell power but also its energy efficiency by 25%. Comparison of electrochemical impedance spectroscopy (EIS) responses of MEA-LTP and MEA-HTP indicated that an extension of the triple phase boundary occurred in MEA-LTP, which was consistent with the results of the MEA performance analysis. - Highlights: • MEA activation at low and high P and T was studied and compared. • High steady state performance achieved by the activated MEA at low P and T. • Low R_ct and R_mt obtained by the activated MEA at low P and T. • Low stress condition for MEA activation is more effective than high stress status.