Visualizing Bubble Flows in Electrolyzer GDLs Using Microfluidic Platforms

Abstract

In this study, microfluidic platforms were used to visualize air bubble transport in two-dimensional (2D) representations of gas diffusion layers (GDLs) to gain insight into how the geometrical features of the GDL impact multiphase flow in polymer electrolyte membrane (PEM) electrolyzers. Two dimensional porous networks were designed using volumetric pore space information, such as average porosity and average throat size obtained from micro-computed tomography (micro CT) visualizations. Microfluidic chips were fabricated to represent felt, paper, and sintered powder GDLs and used to simulate the transfer of oxygen bubbles generated at the catalyst layer, through the GDL towards the flow channels of a PEM electrolyzer. The results of this work indicate that microfluidic platforms for evaluating PEM electrolyzer GDLs is highly promising.