Japan and California have long been at the forefront of embracing hydrogen fuel-cell technologies, a promising form of renewable energy capable of powering vehicles and providing clean energy to manufacturing sectors. However, the widespread adoption of this technology has been hindered by its reliance on expensive precious metals like platinum. Engineers at Washington University in St. Louis are now tackling this challenge by developing methods to stabilize more abundant iron components for use in fuel cells, potentially replacing costly platinum and making hydrogen fuel-cell vehicles more affordable.
“The hydrogen fuel cell has been successfully commercialized in Japan and California in the U.S.,” said Gang Wu, a professor of energy, environmental and chemical engineering at the McKelvey School of Engineering. “But these vehicles struggle to compete with battery vehicles and combustion engine vehicles, with cost being the main issue.”
Cost Challenges and Technological Innovations
A typical $30,000 gas-powered vehicle could cost as much as $70,000 if converted to a fuel-cell vehicle, according to Wu. The platinum catalysts are the most expensive component, accounting for about 45% of the total cost of fuel cell stacks. Notably, these precious metals do not benefit from economies of scale, and increased demand for fuel-cell power systems could further escalate the already high price of platinum.
In a study published in Nature Catalysis, Wu and his team detailed their approach to stabilizing iron catalysts for use in fuel cells. This breakthrough could significantly reduce costs for fuel-cell vehicles and other niche applications, such as low-altitude aviation and artificial intelligence data centers.
Understanding Hydrogen Fuel Cells
Hydrogen fuel cells generate electricity with zero emissions by combining hydrogen and oxygen—two elements of water. Through a catalyst, these elements produce water, electricity, and heat until the hydrogen supply is exhausted, while oxygen is sourced from the surrounding air. Refueling hydrogen fuel-cell vehicles at large stations is similar to refueling fleets of school buses at centralized locations, addressing potential infrastructure challenges.
According to the Environmental and Energy Study Institute, fuel cells can extract more than 60% of their fuel’s energy, compared to less than 20% for internal combustion engines. This efficiency can reach 85% when the heat generated by the fuel cell is also utilized for electricity.
Overcoming Stability Issues
Unlike electric battery-run cars, hydrogen fuel-cell vehicles cannot be recharged using home electricity sources, necessitating an affordable and accessible hydrogen refueling infrastructure. Utilizing plentiful and affordable iron catalysts could help reduce these costs. However, researchers first needed to enhance the stability of iron to withstand the fuel-cell chemistry involved.
Wu and his team achieved this by creating a chemical vapor of gases to stabilize the iron catalysts during thermal activation. This innovative approach significantly improved catalyst stability while maintaining adequate activity in proton exchange membrane fuel cells (PEMFCs). The result was a substantial improvement in the durability of iron catalysts, along with increased energy density and lifespan.
“After suffering from the poor stability for decades, now we were able to address the critical problem,” said Wu, who noted that the next steps will involve further refining their processes to make iron catalysts even better than precious metals for the fuel cells of tomorrow.
The Path Forward
The team chose PEMFCs among different fuel types because they best serve heavy-duty vehicles like transport trucks, buses, and construction equipment—vehicles that already utilize centralized fueling centers. The technology’s initial adoption by heavy-duty vehicle fleets could further reduce costs as it becomes more widespread and efficiencies of scale are realized.
Financial support for this research includes contributions from Washington University in St. Louis, the National Science Foundation (CBET-2223467), and the U.S. Department of Energy (DOE), Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office.
This development represents a significant step toward making hydrogen fuel cells a more viable and cost-effective solution for clean energy, potentially transforming the transportation and energy sectors in the coming years.
