A dedicated compression device for high resolution X-ray tomography of compressed gas diffusion layers

Area of Science:

• Materials Science
• Electrochemistry
• Engineering

Background:

• Gas diffusion layers (GDLs) are critical components in fuel cells, influencing performance and durability.
• Understanding GDL microstructure under compression is essential for optimizing fuel cell design.
• Current methods often fail to replicate realistic operating conditions.

Purpose of the Study:

• To develop and validate an experimental approach for studying GDL microstructure under compression.
• To quantify the impact of compression on GDL geometrical parameters.
• To investigate the effects of flow-field geometry on GDL compression.

Main Methods:

• Design of a specialized compression device for in-situ synchrotron tomography.
• Tomographic imaging of GDL samples at varying compression levels (0% and 30% vol.%).
• Evaluation of transport-relevant parameters: porosity, pore size, and tortuosity distributions.

Main Results:

• Synchrotron tomography successfully captured 3D GDL microstructure under compression.
• Non-uniform compression observed: homogeneous under ribs, less so under channels.
• GDL fibers protrude into flow channels, potentially hindering gas transport and water removal.

Conclusions:

• The developed experimental approach enables realistic GDL microstructure analysis.
• Non-uniform compression significantly affects GDL properties and fuel cell performance.
• Fiber intrusion into flow channels poses a challenge for efficient fuel cell operation.