Abstract
An empirical equation 
was shown to fit the experimental cell potential 
vs. current density 
data for proton exchange membrane fuel cells (PEMFCs), at several temperatures, pressures, and oxygen compositions in the cathode gas mixture. The exponential term compensates for the mass‐transport regions of the 
vs. 
plot; i.e., the increase in slope of the pseudolinear region and the subsequent rapid fall‐off of the cell potential with increasing current density. As has been previously shown, the terms 
and 
yield the electrode kinetic parameters for oxygen reduction in the PEMFC and 
represents the resistance, predominantly ohmic and, to a small extent, the charge‐transfer resistance of the electro‐oxidation of hydrogen. The exponential term characterizes the mass‐transport region of the 
vs. 
plot. The parameter 
has more pronounced effects than the parameter 
in this region. A physicochemical interpretation of these parameters is needed.