Janus Gas Diffusion Layer for Enhanced Water Management in Proton Exchange Membrane Fuel Cells (PEMFCs)

The proton exchange membrane fuel cell (PEMFC) is one of the most promising energy conversion devices. However, a PEMFC is hindered by the serious problem of water management. Herein, a Janus gas diffusion layer (Janus GDL) that can spontaneously transport water from the hydrophobic side to the hydrophilic side was prepared by layer-by-layer filtration and laser drilling. The Janus GDL exhibits a remarkable antiflooding capability at the equivalent current density of 3.25 A cm–2 (2.3–2.5 times compared to the commercial GDL) in the half-cell. Because of the low water breakthrough pressure (29 Pa), the Janus GDL drains excessive water immediately, thus preventing heavy electrode floodings. As a result, the Janus GDL shows a higher peak power density (1.89 W cm–2 vs 1.17 W cm–2 of commercial GDL). Therefore, the Janus GDL is promising for use in PEMFCs and other electrochemical devices to get a good water management.