Agglomerate modeling of cathode catalyst layer of a PEM fuel cell by the lattice Boltzmann method

Lattice Boltzmann method is a relatively new micro-scale modeling technique for complex fluid systems that offers several advantages over more conventional numerical methods and hence has attracted interest of researchers. However, lattice Boltzmann modeling of PEM fuel cell electrodes has faced with some challenges in tackling electrochemical reaction in the catalyst layer. In the present study, a two-dimensional single-phase lattice Boltzmann agglomerate model of the cathode catalyst layer of a PEM fuel cell is developed for the first time. After validation of different aspects of the model, the reactive air flow in a cathode electrode is simulated through a multi-scale lattice Boltzmann approach. Species distributions in the pore region, electrical potential distribution in the electrolyte film, and current density distribution at the interface of membrane and catalyst layer are presented and analyzed; both uniform and non-uniform agglomerate arrangements are simulated. The novel model can be adopted to simulate reactive flow in a cathode catalyst layer with a more complicated arrangement of agglomerates representing a realistic microstructure.