Nanofiber Cathodes for Low and High Humidity Hydrogen Fuel Cell Operation

A new fuel cell electrode fabrication scheme based on nanofiber electrospinning has been devised and nanofiber cathode membrane-electrode-assemblies (MEAs) were evaluated in a hydrogen/air fuel cell at 80 degrees C for low and high feed gas humidification conditions. MEAs were constructed from an electrospun mat with a fiber composition of 72 wt% Pt/C, 15 wt% poly(acrylic acid), and 13 wt% Nafion (R). The Pt loading of the mat was 0.1 mg/cm(2). Mats were hot-pressed onto Nafion (R) 212 membranes with a decal anode (at 0.4 mg(Pt)/cm(2)). Under fully humidified conditions, the nanofiber cathode MEA generated very high power densities (e. g., 485 mW/cm(2) at 0.6 V vs. 345 mW/cm(2) for a 0.1 mg(Pt)/cm(2) decal cathode MEA). At lower feed gas humidities, the difference in power output for the nanofiber and decal MEAs was more pronounced, e. g., at 40% RH, the power density with the nanofiber cathode was more than double that for the decal MEA (132 mW/cm(2) vs. 58 mW/cm(2) at 0.6V).