Computational Modelling of Fuel Cell Electrodes
Fuel cells are efficient electrochemical energy conversion devices that can provide zero emission power for applications ranging from portable electronics and road vehicles, to residential power generation. They have the advantages of high energy density, fast start-up, and scalability. A key component of a fuel cell is the electrode, which facilitates the electrochemical reaction and the transport of reactants, charge, and byproduct heat and water. Fuel cell electrodes consist of three tightly integrated layers having distinct characteristics: a catalyst layer, a micro-porous layer, and a gas diffusion layer. The complex porous structure and morphology of the layers largely determine the effectiveness of the transport processes and in turn the overall performance, cost and durability of a fuel cell.For instance, when operating at higher current densities, or when local water and heat management are inadequate, water condensation leads to the formation of liquid water that “floods” the poresof the electrode, thus impeding the transport of reactant gases. This not only reduces performance but can also promote physico-chemical degradation processes. In this talk we will discuss some of the challenges and progress toward modelling and understanding the multiphysics, multiscale transport in the various porous layers of PEM fuel cells through a combination of advanced microscopy, numerical reconstruction, and pore scale simulations. We will also present some recent progress in the modelling and simulation of the fabrication process that determines the structure and morphology of porous catalyst layers.