To improve the cold-starting performance of a polymer electrolyte fuel cell (PEFC), we devised a microporous layer (MPL) with a planar wettability distribution. Hydrophilic and hydrophobic strips in the MPL were arrayed in alternating rows in the in-plane direction. Due to the exclusion of liquid water from the hydrophobic regions, the water moved towards the hydrophilic areas and was absorbed. Since frozen water near the interface between the MPL and catalyst layer (CL) was thought to inhibit the continuation of power generation, minimizing the amount of water on the CL was important. We extended the continuous operating temperature range to encompass lower temperatures and improved the operating time of the PEFC at subfreezing temperatures.
Keywords fuel cell, cold start, microporous layer, wettability distribution