Universal mass-transport limited fuel cell current curves

A unit fuel cell with straight gas channels operating in low voltage conditions is considered. Anode electrochemical losses are neglected and a particular, simple form for mass transport limitations to the cathode oxygen reduction electrochemistry is taken and validated with experimental results. With experimentally fitted parameters, it is found that the mass transport limitations dominate the behaviour of the local current density at low voltages. Combined with a simple channel model for oxygen flux, this leads to a description of local current densities independent of cell voltage, assuming only that it is low. The work is motivated by Polymer Electrolyte Membrane fuel cells but the ideas are general enough to be applied to other fuel cell types.