Degradation analysis of polymer electrolyte membrane water electrolyzer with different membrane thicknesses

A constant current density of 3.0 A/cm2 was applied to PEMWE assembled with three commercial Nafion membranes (NR212, N115, and N117) for 144 h to investigate the influence of membrane thickness on the cell durability. The results show that N115-cell exhibits an improvement in performance after 144 h by the decrease of ohmic resistance caused by the topology adaptation. The cells with NR212 and N117 showed voltage increases, and the most significant degradation could be observed in the NR212-cell. The highest exposing potential of N117-cell accelerated the passivation of the porous transport layer (PTL) and the catalyst dissolution, consequently increasing ohmic losses and kinetic losses. The remarkable performance losses of the NR212 originated from severe ohmic degradation. This phenomenon was attributed to the pinhole formation on the membrane and the resulting decrease in the electrical conductivity of the iridium catalyst layer due to the reduction of iridium oxide catalyst.