Investigating low and high load cycling tests as accelerated stress tests for proton exchange membrane water electrolysis

In this paper, novel accelerated stress protocols have been proposed based on polarization and electrochemical impedance spectroscopy characterization conducted on three single cell assemblies: one for reference at constant load of 1 A cm −2 and two dynamic loads consisting of a high load cycling between 1.2 A cm −2 and 2 A cm −2 and a low load cycling between 0 A cm −2 (open circuit voltage) and 0.5 A cm −2. Results showed that the degradation rate is 29.8 µV h−1 for constant load test, 51.4 µV h−1 for low load cycling test and -55.8 µV h−1 for high load cycling test. Compared to the constant load operation, low load cycling operation could accelerate the cell performance decrease mainly due to cathode catalyst degradation. The high load cycling could lead to increased cell performance by reducing the ohmic resistance but degrades the anode catalyst significantly, which could compromise the cell's long-term stability. Besides, it is believed that this dynamic condition could accelerate the cell aging by accelerating the membrane thinning.