Performance of polymer electrolyte fuel cells with gradient pore microporous layers at moderate/high humidity

In this paper, carbon black and acetylene black are used as conductive materials of microporous layer (MPL) in GDL, and four MPLs with different materials and structures are prepared by spray method. Respectively, GDL prepared using carbon black, acetylene black, blend of carbon black and acetylene black, double-microporous layer structure are used. In double MPLs, MPL near carbon paper side is acetylene black, and MPL near catalyst layer side is carbon black. The polarization curve, power density, electrochemical impedance spectroscopy, water permeability, pore size distribution and water contact angle of the four samples are tested. It indicated that GDL with double MPL structure has maximum current and power density. When humidity is 60%, limiting current density increased by 41%, and power density increased by 30% (Relative to GDL without gradient pore size). When humidity is 100%, limiting current density increased by 41.3%, power density increased by 50% (Relative to GDL without gradient pore size).