Abstract
In situ visualization of liquid water distribution in PEM fuel cell with and without MPL and its effect on the fuel cell performance was investigated. The liquid water accumulation at the interface of catalyst layer (CL) and gas diffusion media (GDM) was observed to have large impact on the performance of fuel cell without MPL. The MPL reduces the liquid water at the interface of CL and GDM and enhance the performance of the fuel cell with MPL. The effect of gas flow rate on the liquid water distribution and performance of the fuel cell with MPL was also studied. The higher water content at the cathode MPL/GDL boundary was observed and corresponds for the large decreasing in cell voltage when lower the gas flow rate.