Phase-contrast X-ray imaging of the gas diffusion layer of fuel cells

The understanding of and in situ observation of the transport and distribution of water in carbon‐paper gas diffusion layers (GDLs) using non‐destructive imaging techniques is critical for achieving high performance in polymer electrolyte fuel cells (PEFCs). To investigate the behavior of water in GDLs of PEFCs, phase‐contrast X‐ray imaging via X‐ray interferometric imaging (XII) and diffraction‐enhanced imaging (DEI) were performed using 35 keV X‐rays. The XII technique is useful for the radiographic imaging of GDLs and in situ observations of water evolution processes in operating PEFCs. DEI provides a way for tomographic imaging of GDLs in PEFCs. Because high‐energy X‐rays are applicable to the imaging of both carbon papers and heavy materials, which make up PEFCs, phase‐contrast X‐ray imaging techniques have proven to be valuable for investigation of GDLs.