Review—Modelling Catalyst Layer Performance in Device-Scale Polymer Electrolyte Membrane Fuel Cell Simulation

Theoretical models used to describe the catalyst layers (CLs) in polymer electrolyte membrane fuel cells (PEMFCs) are reviewed, with a focus on continuum treatments as incorporated in device-scale models used to predict and optimise PEMFC operating performance. Consideration is given to the mathematical relationships between CL design properties (Pt/C mass ratio, catalyst loading, ionomer loading), and physical properties. Relevant physical models are summarised, considering couplings between the CL and the phenomena of charge transfer, reactant mass transfer, hydrogen oxidation, and oxygen reduction electrode kinetics, heat transfer, and water balance. The relevance of thin film methods (through-thickness homogenisation) is compared to those resolving the macroscopic depth of the CL. Specific continuum homogenisations of microstructural models incorporating CL transport limitations in a continuum treatment, such as the agglomerate model, are discussed.