Abstract
Methanol crossover is a serious problem for a direct methanol fuel cell (DMFC) since it causes mixed potential and waste of fuel. The amount of methanol crossover directly depends on the methanol concentration at the interface between the anode catalyst layer and the electrolyte membrane. However, no technique is available to measure the methanol concentration at this interface in an operating DMFC. Previous experimental results show that sharp peaks exist in the methanol crossover flux when the cell voltage changes abruptly [1]. Systematic studies on these peaks reveal the formation mechanisms. Furthermore, a novel method to determine the methanol concentration at the interface between the anode catalyst layer and the Nafion® electrolyte membrane is developed. Finally, the relationship between the methanol concentration at this interface and the drag coefficients for methanol and water in an operating DMFC are also derived.
•Formation of peaks and valleys in methanol crossover flux are analyzed.•Developed a novel method to determine interfacial methanol concentration.•Methanol drag coefficient is obtained from these peaks and valleys.•Water drag coefficient can also be obtained from these peaks and valleys.
