Integrated multi-mechanism degradation modeling of a catalyst-coated membrane in a PEM electrolysis cell operating under renewable-powered conditions

Green hydrogen from water electrolysis is key to producing electro-fuels for decarbonizing aviation and maritime transport. PEM electrolysis systems offer an efficient and high-purity solution powered by renewable energy. This study modeled a proton exchange membrane (PEM) electrolysis cell and evaluated its performance, accounting for key degradation mechanisms within the catalyst coated membrane (CCM): membrane thinning, iridium dissolution in the anode electrode, and platinum crystallite agglomeration in the cathode electrode. The results indicated that after 20,000 h (2.283 years) of operation, membrane thinning was the primary factor limiting the cell lifetime, increasing the overpotentials and power consumption. It was also observed that increasing the current density of the PEM electrolysis cell from 1 A.cm-2 to 2 A.cm-2 leads to a decrease in cell efficiency and an accelerated degradation rate, resulting in a 27% reduction in lifetime and a 1.78-fold increase in voltage degradation. This study also examined the effects of operating temperature and pressure on cell degradation. Reducing the cell temperature from 80 °C to 70 °C decreased efficiency by 0.64% at the beginning of life (BOL) by increasing the overpotentials. However, this reduction in operating temperature resulted in reduced degradation, leading to 8.18% higher efficiency after 20,000 h of operation. This study also investigated the effects of idle operation and pressure on the degradation of the CCM and identified the operating condition offering the most favorable durability–efficiency trade-off among the evaluated operating conditions.