Effect of operating parameters and anode diffusion layer on the direct ethanol fuel cell performance

A parametric study was conducted on the performance of direct ethanol fuel cells. The membrane electrode assemblies employed were composed of a Nafion® 117 membrane, a Pt/C cathode and a PtRu/C anode. The effect of cathode backpressure, cell temperature, ethanol solution flow rate, ethanol concentration, and oxygen flow rate were evaluated by measuring the cell voltage as a function of current density for each set of conditions. The effect of the anode diffusion media was also studied. It was found that the cell performance was enhanced by increasing the cell temperature and the cathode backpressure. On the contrary, the cell performance was virtually independent of oxygen and fuel solution flow rates. Performance variations were encountered only at very low flow rates. The effect of the ethanol concentration on the performance was as expected, mass transport loses observed at low concentrations and kinetic loses at high ethanol concentration due to fuel crossover. The open circuit voltage appeared to be independent of most operating parameters and was only significantly affected by the ethanol concentration. It was also established that the anode diffusion media had an important effect on the cell performance.

► We examined the effect of operating conditions on polarization curve, OCV and power density of DEFC.
► The OCV is mainly dependent on ethanol concentration.
► The fuel cell kinetics are enhanced by increasing the temperature, backpressure and oxygen flow rate while it is decreased by increasing the ethanol concentration.
► The fuel cell kinetics are independent of ethanol solution flow rate and anode diffusion layer.
► The anode diffusion layer without micro-porous layer showed better overall cell performance.