Hydrogen fuel cells, which use hydrogen and oxygen to generate clean electricity and pure water, are considered among the most promising clean energy sources. However, the accumulation of liquid water inside hydrogen fuel cells is a major roadblock to efficient operation. Researchers from University of New South Wales (UNSW; Sydney, Australia; www.unsw.edu.au) have demonstrated a new internal fuel-cell microstructure that improves water removal and gas transport and increases catalyst utilization. The new fuel-cell architecture directly embeds microscopic channels called lateral bypasses (around 100 μm in width) into the cell’s flow-field ribs (photo). “In conventional designs, water produced during operation accumulates inside the porous layers under the ribs and blocks oxygen transport, which significantly reduces performance. Our design allows excess water to escape naturally before it builds up. What sets this apart is that we achieve this with only minor structural changes, without relying on complex external water-management systems. As a result, we’ve been able to improve power output by roughly 75%, explains Quentin Meyer, Senior Research Fellow at UNSW’s School of Chemistry and lead researcher on the study.
Source: Quentin Meyer, UNSW
By enhancing oxygen transport behavior, the fuel cell can better utilize its catalyst, which can significantly increase efficiency and lower costs. “In traditional fuel cells, platinum is used as a catalyst, but its effectiveness is reduced when water blocks access to the active sites. Because our design improves water removal, those catalytic sites are fully accessible. This means we can either reduce the amount of platinum needed or get more performance from the same amount,” emphasizes Meyer. The team has also demonstrated its lateral bypass technology using platinum-free catalysts, showing promising boosts to fuel-cell productivity.
UNSW has patented its lateral bypass concept and the researchers are now actively working on expanding from laboratory-scale operation. The technology does not require any specialty materials, and builds upon existing fabrication techniques to precisely micro-engineer the lateral bypasses, making scaleup possibilities quite promising. “We are not fundamentally changing the materials; components like the membrane electrode assembly and gas diffusion layers remain the same. Because of this design modification, rather than a brand-new design, the transition from conventional designs to ours should be relatively straightforward from a manufacturing perspective,” concludes Meyer.
Further details of this work are published in the journal Applied Catalysis B: Environment and Energy.