Visualization of Gas Bubble Behavior of a Regenerative Fuel Cell in Electrolysis Mode by Soft X-ray Radiography

摘要

Regenerative fuel cells (RFC) are candidates for hydrogen energy to become common in daily life since it lowers the first investment cost by combining two different devices into one. In an earlier study, it was proved that the hydrogen mass transport was limited by water accumulation, hence lowered the cell efficiency. Soft X-ray radiography experiments performed to investigate hydrogen and oxygen gas bubble behavior in a regenerative fuel cell. The cell was visualized with high spatial resolution at different current densities. The hydrogen gas bubbles appeared first compared to the oxygen, since the higher stoichiometric hydrogen generation and lower solubility of hydrogen in water. The gas bubbles tended to nucleate at certain locations which are thought to be cracks on the catalyst layer.