Degradation of proton exchange membrane fuel cells (PEMFCs) can be accelerated by impurities in the air. In maritime environments in particular, sodium chloride (NaCl) can reduce the performance of membrane electrode assembly (MEA) in PEMFCs. In this context, we experimentally analyzed effect of flow channel depth on PEMFCs humidified with a NaCl solution at the cathode side. The analysis was conducted in serpentine flow channels with different depths of 0.4, 0.8, and 1.6 mm. The initial performance of unit cells was compared to their performance after applying a constant current for 10 hours. Results showed that the degradation rate correlated positively with the flow-channel depth. Channel depths of 0.4 and 1.6 mm resulted in 2.4% and 7.3% decreases in the maximum power density, respectively. For the 1.6 mm channel depth, the activation loss after 10 hours was larger than the initial loss.

In this study, polymer electrolyte membrane fuel cells (PEMFCs) were humidified with NaCl solutions. NaCl solutions were provided to the cathode side of fuel cells by bubbling. De-Ionized water, 3.5 wt% NaCl solution, and 20 wt% NaCl solution were used to evaluate the effects of NaCl. Current density-voltage curves and electrochemical impedance spectroscopies (EIS) of fuel cells were measured. Additionally, the constant-voltage mode long-term stability of PEMFCs humidified with NaCl solution were investigated. Constant-voltage measurements and EIS results imply that the degradation of fuel cells is clearly related with the concentration of NaCl solutions.

In this study, aluminum, used throughout the industry and actively studied for surface modification, is selected as the test subject. Micro-structured through acid etching, nano-structured through alkali treatment to maximize surface roughness, and the superhydrophilic surfaces were fabricated by forming the surface chemicals into aluminum hydroxide (Al(OH)₃). The superhydrophobic surfaces were fabricated through the self-assembled monolayer coating on the surface, and the surface structure and components were analyzed. The superhydrophilicity and superhydrophobicity were applied on the aluminum surface at the bottom of the low speed water vehicle. For the superhydrophilic and superhydrophobic surfaces, the reasons for the drag reduction performance on the bare surface and the difference in the amount of reduction were analyzed. A coating material that strong bonds with the surface are selected for anti-corrosive performance under NaCl solution. To verify that, the contact angle was measured by exposing each prepared aluminum surface to a 3.5% NaCl solution for 14 days. Additionally, we analyzed why the superhydrophobic surfaces were robust against the NaCl solution.