Methanol crossover is a significant concern in direct methanol fuel cells that reduces power and efficiency. The flowing electrolyte – direct methanol fuel cell is a concept intended to combat this issue by using a sulphuric acid flowing electrolyte layer to remove crossed-over methanol before it can reach the cathode.
Hydrodynamic modelling and of the flowing porous electrolyte channel and fuel cell performance experimental studies were conducted. In addition, experimental measurements of the permeability values of porous channel spacers were compared to theoretical values.
It was
recommended that the flowing electrolyte channel should be very thin with a higher sphere diameter and lower porosity with a flow rate high enough to effectively negate methanol crossover. However, a possible alternative may be to use a higher porosity, but increase the flow rate to achieve the same performance; this may result in a lower pressure drop.