Cathode flooding behaviour in alkaline direct ethanol fuel cells

In an alkaline fuel cell, such as a direct ethanol fuel cell (DEFC), owing to the fact that water is consumed as a reactant at the cathode and the electro-osmotic drag (EOD) moves water from the cathode to the anode, a conventional conception is that the cathode flooding is unlikely. In this work, however, it is shown experimentally that cathode flooding also occurs in an alkaline DEFC, primarily because of the fact that the diffusion flux from the anode to the cathode outweighs the total water flux due to both the oxygen reduction reaction and EOD. More interestingly, rather than in acid electrolyte based fuel cells where the cathode flooding occurs at a high (limiting) current, in an alkaline DEFC the cathode flooding occurs at an intermediate current.