Impact of Structural Variations in Gas Diffusion Layers on Effective Mass Transfer in PEMFCs Using the Lattice Boltzmann Method

In this paper, a thorough computational model is used to investigate the heterogeneous mass transport properties in the gas diffusion layers (GDLs) of proton exchange membrane fuel cells (PEMFCs). In PEMFCs, the GDL is essential for the movement of reaction gases and the expulsion of water generated during the process. One strategic way to improve PEMFC performance is to alter the GDL structure. Therefore, this paper introduces the structural modifications in the GDL to improve and optimize fuel cell efficiency. The GDLs are stochastically reconstructed in four distinct configurations: fixed-diameter fibers, fixed-diameter spheres, random-diameter spheres, and a combination of fixed-diameter fiber/spherical. These structures are considered to quantify their influence on diffusion within the GDL. The lattice Boltzmann method (LBM) is employed to simulate the GDL model via OpenLB. The results reveal that variations in structure, thickness, and porosity lead to changes in pore size, shape, and distribution, thereby significantly influencing mass transport properties. The findings indicate that the flow of flux through the entire GDL is easier in a spherical structure as compared to a fiber structure. This analytical approach provides valuable insights into microscopic flow phenomena within porous structures and their consequential impact on macroscopic transport properties.