Abstract
In recent years, many approaches have been presented to improve the cathode flooding in order to obtain better cell performance. These approaches can be categorized as (1) by improving the flow field plate design and (2) by incorporating a hydrophobic micro porous layer (MPL) between the GDL and catalyst layer. The main function of MPL is to promote back-flow of liquid water towards the anode across the proton exchange membrane and alleviates cathode flooding. The objective of this study is to investigate the effects of different porous structures in MPL on the performance of a DMFC. In this paper, we employ different size of carbon particles to build the MPL with different porous structures and observe that the contact resistance is reduced efficiently by the MPL comprised of finer carbon particles. However, the larger carbon particles just form another layer upon the carbon cloth, which increase the contact resistances. At performance comparison, the advantages of MEA with MPL are more evident as temperature is increased. At low operation temperature, the difference between MEA with MPL and without MPL is not very evident. But the MEA with MPL becomes better than untreated MEA at high operation temperature.