The problem of oxygen starvation on PEMFC is often observed (partially or totally in a cell). It is caused by water management problems (water droplet in the channels) or air management faults (delay during peak power). In our previous work, the current distribution has been measured along the cell during air starvation and calculated by modeling; the effects of the local temperature and the hygrometry in the MEA have been identified. However the mechanisms of degradation are still not completely understood. Several points have to be investigated like the short and long dated changes in performances and the degradation mechanisms in such a condition. In this paper, the study is completed by two sets of experiments. The first one is carried out with a bi-cell stack developed with specific design to compute the local current density by measuring the local induced magnetic field. Secondly, a long time ageing test is run with a 6 cells stack (220 cm2) during oxygen starvation cycling conditions. Both tests (with characterizations) coupled with the 2D serpentine meshing stack model (taking into account transport phenomena, heat transfer and semi-empirical electrochemical reactions) provide information on the MEA local conditions effects during oxygen starvation. Especially the different reaction mechanisms at the cathode side are explained likewise the consequences on ageing.

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