Turning Hydrogen Fuel Cells from Luxuries into Accessible Technologies
Japan and California are at the forefront of adopting hydrogen fuel cell technologies, a promising renewable energy solution that holds potential for powering vehicles and providing clean energy for various manufacturing sectors. However, despite their advantages, these technologies remain prohibitively expensive primarily because they depend on precious metals like platinum.
Engineers at Washington University in St. Louis are tackling this issue head-on by seeking ways to make iron, a common and less costly material, stable enough for use in fuel cells. If they succeed in replacing expensive platinum with affordable iron components, it would significantly reduce the cost of hydrogen fuel-cell vehicles.
Gang Wu, a professor specializing in energy, environmental, and chemical engineering at the McKelvey School of Engineering, remarked, "Though the commercialization of hydrogen fuel cells has been achieved in Japan and parts of California, these vehicles find it difficult to compete against traditional battery-operated and combustion engine vehicles, largely due to high costs."
He estimates that while a typical gasoline vehicle might cost around $30,000, a hydrogen fuel-cell car could set consumers back as much as $70,000. The primary culprit behind this steep price tag is the platinum catalysts, which represent nearly 45% of the overall expenses associated with fuel cell stacks. Additionally, the precious nature of platinum means it does not benefit from economies of scale; thus, an increase in demand for fuel-cell systems only escalates its already high market price.
In recent research published in Nature Catalysis, Wu and his team detailed their innovative technique for stabilizing iron catalysts within fuel cells. This advancement could potentially lower the costs associated with fuel-cell vehicles as well as niche applications such as low-altitude aviation and data centers that support artificial intelligence.
Hydrogen fuel cells generate electricity with zero emissions by combining hydrogen and oxygen—two elements found in water. Through a catalytic process, these two gases react to produce water, heat, and electricity until the hydrogen is depleted, while oxygen is drawn from the air without limits. One of the appealing aspects of hydrogen fuel-cell vehicles is that they can refuel at large stations, akin to how school bus fleets replenish their fuel at centralized locations, making the infrastructure challenges more manageable. Although hydrogen fuel cells promise clean energy, the hefty costs tied to the precious metals involved hinder their broader adoption.
The Environmental and Energy Study Institute reports that fuel cells can harness over 60% of the energy from their fuel, while traditional internal combustion engines manage to recover less than 20% of the energy contained in gasoline. Notably, this efficiency can rise to 85% when the waste heat produced by the fuel cell is also utilized for generating electricity.
Unlike battery-powered electric cars, recharging hydrogen fuel-cell vehicles using home electricity is not feasible. Therefore, for this clean technology to thrive, there must be an affordable and widely available hydrogen refueling infrastructure. Transitioning to the use of abundant and economical iron catalysts could significantly help in reducing overall costs. However, researchers needed to first ensure that iron could withstand the specific chemistry of fuel cells.
Wu and his team developed a novel method involving a vaporized chemical process designed to stabilize iron catalysts during thermal activation. This groundbreaking approach greatly enhances the stability of the catalysts while preserving their effectiveness in proton exchange membrane fuel cells (PEMFCs). As a result, the durability of iron catalysts has improved significantly, alongside increased energy density and lifespan. The team opted for PEMFCs because they are particularly suited for heavy-duty vehicles like trucks, buses, and construction machinery—vehicles that typically refuel at centralized stations. Prioritizing the adoption of this technology in heavy-duty fleets is not only cost-effective but could also reduce expenses as the technology becomes more widespread, benefiting from increased efficiencies.
"After decades of battling poor stability, we have finally made progress in solving this critical issue," Wu stated, adding that future work will focus on further enhancing their methods to ensure that iron catalysts outperform precious metals in the fuel cells of the future.
This research was supported by Washington University in St. Louis, the National Science Foundation (CBET-2223467), and the U.S. Department of Energy's Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office.
