Enhancing the performance of proton exchange membrane fuel cell using nanostructure gas diffusion layers with gradient pore structures

The gas diffusion layer (GDL) plays a vital role in water management of proton exchange membrane fuel cells. In this study, GDLs with nanoscale gradient pore sizes (nano-GDLs) are fabricated using electrospinning to explore the influence of the gradient layer number and degree of the pore size gradient on the water transport performance. The breakthrough pressure and water saturation tests indicate that nano-GDLs with uniform and gradient structures have higher breakthrough pressures and lower water saturation compared with those of the commercial Toray GDL, which facilitates back diffusion of water through the membrane and water discharge in the GDL. Specifically, among the nano-GDLs with a gradient structure, the three-layer medium-gradient nano-GDL sample (3-MG) possesses the maximum breakthrough pressure and minimum water saturation ratio. The fuel cell test determined that the maximum power density of the 3-MG nano-GDL sample is 14% higher than that with commercial Toray GDL without cathode humidification.