Gas purging effect on the degradation characteristic of a proton exchange membrane fuel cell with dead-ended mode operation II. Under different operation pressures

Gas purging is an effective method to remove the accumulated nitrogen and liquid water during the dead-end operation of polymer electrode membrane fuel cell (PEMFC). The effect of the operation pressure on the degradation characteristic of single cell is investigated under continuous gas purging cycles. Various diagnostic techniques including electrochemical characterization, physicochemical properties, and microstructure of the membrane electrode assembly (MEA) are applied to characterize the performance of the assembled single cells. After 1000 purging cycles, the single cell exhibits an obvious performance degradation, which can be proven from the change of the electrochemical surface area (ECSA), contact angle, cracks on the membrane and membrane thickness. The single cell with a relatively low oxygen pressure of 50 kPa has serious performance degradation. Comparatively, the assembled PEMFC has an enhanced durability with a high oxygen pressure of 200 kPa during the purging cycles under dead-ended operation mode.