Metal foam flow fields in polymer electrolyte membrane fuel cells: Performance and durability under severe operating conditions

While it is known that PEMFCs with inserted metal foam exhibit superior performance under normal conditions compared to serpentine flow fields, the practical application of such configurations does not guarantee continuous operation under optimal conditions. Therefore, the durability and performance under various extreme conditions need to be demonstrated. Through this study, we aim to compare the durability and performance of the metal foam flow field with a serpentine channel under severe operating conditions. We conducted mechanical accelerated degradation tests, electrochemical accelerated degradation tests, and applied low stoichiometric ratio (SR) and low relative humidity (RH) conditions to both channels to compare their performance under each extreme scenario. The metal foam -inserted flow field demonstrated a higher degradation rate but higher power output in all scenarios, with a notable 30.1% degradation rate in the 18 -day without load cycle test, compared to 21.0% in the serpentine flow field. Despite the elevated degradation rate, the metal foam -equipped cell achieved a 15.8% higher maximum power output. Furthermore, the fuel cell with metal foam flow field shows higher air utilization rate and better water management in low stoichiometric ratio and extremely low relative humidity, respectively. In conclusion, this study suggests that the metal foam flow field may not only be a better choice under typical operating conditions but also a superior alternative to the serpentine flow field in various extreme operating conditions.