Stoichiometry Effects in Proton Exchange Membrane Fuel Cells

In this paper, a study of the effects of stoichiometry on the performance of proton exchange membrane fuel cells is presented. Theoretical analysis and experiments were used to show that the electrodes area ratio has effects on stoichiometry of fuel cell reactions and consequently on the cell voltage and on the efficiency of a proton exchange membrane fuel cell. Experimental data was used to estimate the effect of equal electrodes area on the fuel cell reaction. The active electrodes area ratios were adjusted to enhance stoichiometry and consequently improve performance, but improvement was limited due to the low thickness of the membrane. Efficiency values obtained match values published by others. The study concluded that the equal areas electrode-membrane sandwich design of proton exchange membrane fuel cells affects the stoichiometry of the fuel cell reaction and consequently results in efficiency lower than that of the stoichiometric reaction. Keywords— Fuel cell, PEM and electrode