Carbon Corrosion in PEM Fuel Cell Dead-Ended Anode Operations

Abstract

This paper investigates the effects of dead-ended anode (DEA) operation on the electrode carbon corrosion of the Proton Exchange Membrane (PEM) fuel cell. A reduced order isothermal model is developed focusing on the species concentration along the channel and associated membrane phase potential. This model explains, and can be used to quantify, the carbon corrosion behavior during DEA operation of a PEM fuel cell. The presence of oxygen in the anode channel, although normally less than 5% in molar fraction, creates a H2/O2 front as N2 and water accumulate at the end of the channel and hydrogen is depleted along the channel. The presence of oxygen in the anode channel also results in a gradual drop of the membrane phase potential, promoting carbon corrosion in the cathode. The corrosion rate is driven by the local species concentration in the anode, which varies in space and time. In a co-flow configuration, the large spatio-temporal patterns of hydrogen starvation in the end of the anode channel induce the highest carbon corrosion, which, in turn, is shown to be moderated by the decreasing terminal voltage during galvanostatic operation. Although not fully calibrated, the model shows good agreement with preliminary in situ observations.