(Invited) Measuring and Modeling Transport Processes in Porous Electrodes

The porous materials found inside fuel cells and other electrochemical devices differ substantially from the traditional porous media studied by geologists and reservoir engineers (i.e. rock, sand and soil).  The list of challenging features of porous electrode materials is long: they can be extremely thin, nanoporous, electrically conductive, anisotropic, highly porous, fibrous, multilayered, fractured, compressible, and not self-supporting.  As such, the standard set of experimental tools and modeling techniques are not always suitable or applicable.  In this tutorial, progress made in porous materials characterization in the fuel cell field over the past decade will be summarized, but this tutorial will be of interest to workers in any application involving engineered porous materials.  Specific topics will include pore phase measurements of effective diffusivity and permeability, solid phase measurements such as electronic and thermal conduction, multiphase flow related processes such as capillary pressure curves and breakthrough conditions, as well as pore space characterization techniques such as porosity, pore size distributions, and X-ray tomography.  The role and value of the various transport parameters will also be discussed in relation to modeling and simulation.