Effects of Gas Diffusion Layer Substrates on PEFC Water Management: Part I. Operando Liquid Water Saturation and Gas Diffusion Properties

Gas diffusion layers (GDLs) are commonly known as one of the critical water management components in polymer electrolyte fuel cells with significant impact on electrochemical cell performance. Increasing levels liquid saturation GDLs, especially during high-current-density operation, limit gas transport from flow field channels to catalyst layer surfaces and hence reduce To provide GDL material selection modification guidelines, a thorough understanding underlying structural factors materials their influence is required. In this work, operando X-ray tomographic microscopy (XTM) was employed investigate behavior for three commercial i-E curves current jump characterization. Liquid volume fractions, profiles cluster distributions were analyzed understand observed discrepancies Furthermore, saturation-dependent relative diffusivities derived via direct numerical simulations, substrates performance thoroughly discussed respect structure thermal properties.