Application and localized corrosion of ruthenium oxide-coated titanium anode plates for a 10 kW fuel cell stack under dynamic load cycling

Understanding the corrosion behavior of bipolar plates (BPPs) and their coatings under dynamic load cycling (DLC) is crucial for the commercial application of proton exchange membrane fuel cells (PEMFCs). This study employs a PEMFC stack comprising titanium anode plates coated with ruthenium oxide to investigate the degradation of these components after DLC testing, specifically under conventional operating conditions (75 °C for 1000 and 3000 h) and accelerated aging conditions (95 °C for 100 h). The corrosion behavior and degradation mechanisms of the coating and TA1 substrate in Ti-BPP samples after various DLC tests are analyzed using electrochemical tests, morphological evaluations, and elemental characterization. The results indicate that the morphological and structural changes in BPP after different DLC tests show significant differences. The coating suffered severe damage under high temperature aging conditions. The generation and dissolution of metal oxides on the BPP surface, along with the corrosion and exfoliation of the coating, resulted in increased surface roughness, decreased corrosion resistance, reduced electrical conductivity, and weakened bonding strength between the coating and the BPP substrate. These findings offer insights for optimizing coating materials under high temperature operating conditions and for assessing the corrosion resistance of metallic BPPs.