Chevalier, S.; Fazeli, M.; Mack, F.; Galbiati, S.; Manke, I.; Bazylak, A.; Zeis, R.: Role of the microporous layer in the redistribution of phosphoric acid in high temperature PEM fuel cell gas diffusion electrodes. Electrochimica Acta 212 (2016), p. 187-194
In this work, pore network modelling was used to investigate the leaching of phosphoric acid (PA) in the gas diffusion electrode (GDE) of high temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). A HT-PEMFC GDE composed of a catalyst layer, a microporous layer (MPL) and a fibrous substrate was assembled, and its three-dimensional (3D) geometry was imaged using synchrotron X-ray microcomputed tomography. The spatial distribution of pore spaces and their connections were identified based on the 3D geometry, and an equivalent pore network of the GDE was obtained for simulating the PA transport with an invasion percolation algorithm. The predicted mass redistribution of PA in the GDE was found to be in excellent agreement with experimental values reported in the literature. The presence of the MPL encouraged the containment of PA within the CL and discouraged PA leaching toward the channel.