Carbon corrosion and performance degradation mechanism in a proton exchange membrane fuel cell with dead-ended anode and cathode

Abstract

This paper presents the work on a PEMFC (proton exchange membrane fuel cell) with DEAC (dead-ended anode and cathode) to achieve high hydrogen and oxygen utilization. Gas purging is an effective way to remove the excess water and maintain normal operation of fuel cell while the voltage drops to the set value chosen arbitrarily due to accumulation of generated water. However, serious carbon corrosion has been observed in MEA (membrane electrode assembly) under this purging model. Voltage degradation process during one purging cycle can be divided into three stages: dehydration of membrane induced ohmic loss, quasi-equilibrium state, and flooding induced concentration polarization. To improve the lifespan of PEMFC, gas purging should be conducted before water flooding. The operation time till the quasi-equilibrium state is suggested as the purging duration in the subsequent research. The results show that with the introduction of time regulator purging strategy, the decay rate of the carbon corrosion is greatly reduced. Moreover, it has also been found that the cell performance and purge cycle duration increase with increasing operating pressure, whereas they decrease with the increase in current density.