FIB+SEM Tomography and Numerical Simulation of Corroded PEM Fuel Cell Cathodes

Carbon support corrosion in PEM fuel cell cathodes causes severe polarization losses due to mass transport resistance and underutilization of the expensive platinum catalyst. Tomography by FIB+SEM serial sectioning has recently been demonstrated on PEM fuel cell cathodes and the technique is used here to image and generate 3D reconstructions of small volumes (~3μm³). Morphological changes following extensive carbon corrosion were observed and quantified. Direct simulations were performed on the 3D reconstruction generated from SEM data which allowed for calculation of effective transport properties, notably effective diffusion coefficients, porosity, and tortuosity.