On the Concentration Overpotential of PEFC with Micromachined Ti Current Collector

Abstract

Micromachined titanium thin film current collector, Ti-CC, that is developed in our previous work is used to investigate the concentration overpotential due to the liquid water filling in the through-holes of Ti-CC. The effects of the Ti-CC porosity, volumetric flow rate and the channel/rib width on i-V characteristics are examined. Previously proposed model for the limiting current density can describe the trend in experimental data. Comparison with the results of visualization experiment confirms the feasibility of the newly developed model for i-V relation at each water coverage ratio of the Ti-CC. The results quantitatively show the importance of concentration overpotential due to the water droplet and suggest possible improvement of the cell performance with proper liquid water management.

Keywords

• pefc
• gas diffusion layer
• micromachining
• current collector
• water management
• modeling