Researchers at Los Alamos National Laboratory (LANL) have developed an alternative electrode structure—a grooved electrode—that enhances proton exchange membrane fuel cell (PEMFC) performance and durability by coupling high ionomer (ion-conducting binder) content for improved H⁺ transport with grooves for rapid O₂ transport.

In a paper published in Nature Energy, the team reports that grooved electrodes provide up to 50% higher performance than state-of-the-art conventional electrodes under standard operating conditions.

The grooved electrode design enables the transport of oxygen and protons to be partitioned into separate grooves and ridges, respectively, enabling faster movement of both species, and hence higher fuel cell performance. First published in Nature Energy, 2023, by Springer Nature.

The grooved electrode design advance may help optimize next-generation fuel cell technology to power emission-free medium- and heavy-duty transportation.

We had a theory that by reimagining the way electrodes are designed we could achieve improved performance. One of our biggest takeaways is that novel materials are not the only route to improve performance. The way the materials are put together can be equally important.

All we did was take conventional commercially available materials and change the way we put them together to change the microscale architecture, and that resulted in substantially higher performance.

—Jacob Spendelow, corresponding author

Spendelow and Laboratory colleagues developed a grooved electrode design that improves the efficiency with which oxygen and protons are transported through the device. The team fabricated the device at the Laboratory’s Center for Integrated Nanotechnologies, using photolithography and deep reactive ion etching at the micrometer scale (one-thousandth of one millimeter) to pattern silicon templates for electrode fabrication. The resulting electrode consists of catalyst ridges with high ionomer content separated by empty grooves, which protons and oxygen use as pathways to move through the system more efficiently.

The team’s diagnostics, combined with multiphysics modeling and simulations, demonstrated the improved oxygen transport. Machine learning also offered opportunities to guide the calculations of the multiphysics modeling, saving computing time. Notably, grooved electrodes also improved durability, even after carbon corrosion.

The grooved electrode approach is one of several novel fuel cell designs on which the Los Alamos fuel cell program has embarked.

The original fuel cell membrane electrode assembly was invented at Los Alamos more than 30 years ago, but the fuel cell design used today has barely changed. This grooved electrode is one of the first alternative electrodes that can replace the historic Los Alamos electrode.

—Jacob Spendelow

The fuel cell team will continue to develop the grooved electrode design, especially looking to engage with manufacturing-specific research and development. Scaling up the fabrication to deploy it in a roll-to-roll manufacturing facility, with high-speed and low-cost manufacturing, is a long-term goal.

The work was supported by the Hydrogen and Fuel Cell Technologies Office, Office of Energy Efficiency and Renewable Energy, US Department of Energy through the Million Mile Fuel Cell Truck (M2FCT) consortium; by the Laboratory Directed Research and Development program at Los Alamos National Laboratory; by the US Department of Energy Office of Science’s funding of the Center for Integrated Nanotechnologies and the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory.

Resources

• Lee, C., Kort-Kamp, W.J.M., Yu, H. et al. (2023) “Grooved electrodes for high-power-density fuel cells.” Nat Energy doi: 10.1038/s41560-023-01263-2