Multi-scale pore morphologies of a compressed gas diffusion layer for polymer electrolyte fuel cells

Understanding the pore morphologies of a compressed gas diffusion layer is critical to improve the performance of polymer electrolyte fuel cells. In this study, the effect of compression on the cell performance was investigated. Increasing the gas diffusion layer compression increases oxygen transport resistance. Moreover, the pore morphologies of the compressed gas diffusion layer were investigated using mercury intrusion porosimetry with a simple compression device and synchrotron X-ray computed microtomography. The average pore diameter of the fibrous substrate reduced applying compression pressure, whereas that of the micro-porous layer remained unchanged even at high compression (38.6%). In addition, the oxygen transport resistance calculated from the structural parameters of a compressed gas diffusion layer, where porosity and pore diameter are explanatory factors, was in good agreement with the oxygen transport resistance obtained by fuel cell testing. (C) 2020 Elsevier Ltd. All rights reserved.