PEM fuel cell durability with transportation transient operation

PEM fuel cell durability testing is performed with tests conducted using steady-state conditions, with dynamic conditions using power cycling simulating a vehicle drive cycle and by accelerated testing methods. The long-term performance characteristics of MEAs, Electrocatalysts and Gas Diffusion Layers (GDLs) and their impact on PEMFC durability are evaluated in terms of their associated degradation mechanisms. Testing simulating automotive drive cycles show a greater rate of particle growth than do tests in which the cell potential is held constant. The loss of electroactive Pt surface area is shown to be due primarily to the growth in platinum particle size; particle growth appears to have multiple growth mechanisms. Cathode particle size growth is dependent on temperature, relative humidity and potential. Cell performance degradation due to mass transport limitations correlates with changing hydrophobicity of GDL materials. copyright The Electrochemical Society.