Lattice Boltzmann Simulation of PEMFC Catalyst Degradation through Electrochemical Ostwald Ripening

Abstract

Among other factors, achieving CO2 savings targets relies on addressing high-power vehicles, wherein Polymer Electrolyte Membrane Fuel Cells (PEMFCs) emerge as a promising alternative for emission reduction. However, their implementation demands substantial research efforts. PEMFCs must endure higher temperatures and exhibit extended life time, necessitating thorough degradation analyses. Experimental studies face time constraints, making simulations a valuable tool to complement investigations, significantly reducing development time and costs. Furthermore, these validated models open pathways to optimize technology advancements.

This project focuses on simulating the degradation of PEMFC catalysts, employing the Lattice Boltzmann Method (LBM) and grounded in the PALABOS library. The LBM approach allows for microstructure resolved simulations of the degradation processes and therefore for investigating the influence of catalyst layer material properties. Specifically, the study centers on modeling Electrochemical Ostwald Ripening, a phenomenon wherein smaller nanoparticles of Pt dissolve and platinum ions precipitate on larger Pt nanoparticles. As this process unfolds, the catalyst's active surface area diminishes, marking its degradation. The dissolution and precipitation are described using local reactive boundary conditions coupled to the diffusion of platinum ions between the particles.