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°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®. The Pt loading of the mat was 0.1 mg/cm 2. Mats were hot-pressed onto Nafion® 212 membranes with a decal anode (at 0.4 mgPt/cm2). Under fully humidified conditions, the nanofiber cathode MEA generated very high power densities (e.g., 485 mW/cm2 at 0.6 V vs. 345 mW/cm2 for a 0.1 mg Pt/cm2 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/cm2 vs. 58 mW/cm 2 at 0.6V ). © 2011 ECS - The Electrochemical Society.