Synchrotron X-ray radiographic investigations of liquid water transport behavior in a PEMFC with MPL-coated GDLs

Synchrotron X-ray radiography was employed to visualize the distribution of liquid water throughout an operating polymer electrolyte membrane fuel cell (PEMFC). The behavior of liquid water in the fuel cells assembled with and without micro-porous layers (MPLs) was compared. Through-plane images under various operating conditions combined with PEMFC performance revealed that, under wet conditions, the MPL was associated with an increased number of breakthrough locations, resulting in higher operating potentials. With these results, it is suggested that the MPL prevents liquid water from agglomerating into larger clusters at the catalyst layer/MPL interface, thereby reducing the number of blocked pathways for oxygen transport.

► Synchrotron X-ray radiography was used to visualize dynamic liquid water transport in a PEMFC. ► Breakthrough locations for PEMFCs with and without MPLs were compared. ► MPLs prevent the formation of large connected clusters of liquid water in the GDL.