Air-breathing membraneless laminar flow-based fuel cells: Do they breathe enough oxygen?

Laminar flow-based fuel cell (LFFC) is a relatively new type of fuel cell that does not require the use of proton exchange membrane. While the first-generation LFFC uses dissolved oxygen at the cathode, the second-generation LFFC (2G-LFFC) adopts a more advanced air-breathing design for achieving high power density. The architecture and operational mechanisms of a 2G-LFFC are more complex. In order to gain detailed understanding of the 2G-LFFC, an integrated CFD/electrochemical kinetics modeling study has been conducted to analyze the cell limiting factors and sufficiency of the oxidant supply from air. It is found that under most typical operating conditions, the 2G-LFFC free-breathing mode can supply sufficient oxygen to the electrode reactive surface for cathode half-cell reaction, indicating that the air breathing process is not a limiting factor to the cell performance. However, oxygen starvation will become a major performance limiting factor when the anode is enhanced for higher current density. The results presented in this paper provide useful design guidance for future development of LFFC.