Fighting the Noise: Towards the Limits of Subsecond X-ray Tomographic Microscopy of PEFC

Abstract

Management and removal of liquid water is essential to maintain and improve the overall performance of polymer electrolyte fuel cells (PEFC). X-ray tomographic microscopy (XTM) of PEFCs has been proven as a valuable tool in order to understand accumulation of liquid water in the gas diffusion layer (GDL), both with in-situ and operando setups. Progress in operando XTM of PEFCs has paved the way for 4D imaging studies of the water distribution in the GDL. In order to capture the water dynamics at high current density operation a further decrease of the scan time towards 0.1 s is aspired. In this work different imaging parameters, filters and their consequences on the contrast-to-noise ratio (CNR) of water versus void and water feature detectability have been studied with an ex-situ XTM experiment at the TOMCAT beamline of the Swiss Light Source (SLS) at Paul Scherrer Institut (PSI).