Could Iron-Based Catalysts Make Fuel Cells Viable?

Fuel cells. Elon Musk calls them “fool cells,” largely because there are so many energy conversions involved in making hydrogen and then converting it into electricity that the overall efficiency of the process is much lower than if the same time and effort were used to make battery-electric vehicles instead. Not only that, fuel cells can’t give a vehicle that same kick off the line when the light turns green that a BEV does.

Let’s face it. We can talk about true cost of ownership and reduced maintenance, but it is still that invisible hand pushing you back in your seat when you mash the exhilarator that makes people giggle when they first experience an electric car. Fuel cell powered vehicles still need a battery to provide that instantaneous burst of power we all crave, so if we are going to have a battery anyway, why not just make it big enough to do the job and forget the fuel cell and all its attendant tanks and plumbing?

Those are all excellent questions and most CleanTechnica readers are highly skeptical of fuel cell powered passenger vehicles, though fuel cells might be good for mining trucks and ships. Nevertheless, the main factor holding back wider use of fuel cells is cost. It takes a catalyst to convert hydrogen into electricity and today most of those catalysts use a family of six precious metals known as platinum-group metals. While efficient and durable, they are extremely rare, which makes they very expensive. Lately, the price of them has been soaring along with the prices of nickel, manganese, and cobalt.

In the world of batteries, iron is beginning to replace nickel, manganese, and cobalt in EV batteries. The so-called LFP (lithium iron phosphate) batteries can’t match the energy density of NMC batteries, but they are considerably less expensive, primarily because iron is abundant and cheap. Now researches at the University of Buffalo report they have created an iron-based catalyst that could significantly lower the cost of fuel cells. The research was published in the journal Nature Energy on July 7.

In their paper, the researchers, led by professor Wu Gang, describe how iron can be combined with nitrogen and carbon to produce a catalyst that is efficient, durable and inexpensive — the three main objectives the US Department of Energy has identified for fuel cell research. “This has been years in the making,” says Wu. “We believe this is a significant breakthrough that will eventually help unleash the tremendous potential of hydrogen fuel cells.”

There are challenges to using iron as a catalyst in fuel cells. For one thing, it lacks the durability to withstand the highly corrosive and oxidative environments found inside fuel cells. To overcome this barrier, the research team bonded four nitrogen atoms to the iron. They then embedded the material in a few layers of graphene “with accurate atomic control of local geometric and chemical structures,” Wu says.

The resulting structure is a vastly improved catalyst. The researchers believe it is the most efficient iron-based catalyst produced to date, exceeding the DOE’s 2025 target for electric current density. Wu says iron-based catalysts have the potential to make fuel cells, particularly hydrogen fuel cells, much more affordable for commercial use. Researchers are planning follow-up studies to further improve the catalyst.

The University of Buffalo research was conducted in collaboration with Argonne National Laboratory, Carnegie Mellon University, Giner Inc, Indiana University, Oak Ridge National Laboratory, Oregon State University; Purdue University, and the University of Pittsburgh. The study was supported the US Department of Energy and the US National Science Foundation. The University of Buffalo and Giner have filed joint patent applications naming Wu and his two co-inventors.

The Takeaway

This is one of those announcements that may mark a turning point for clean transportation. It doesn’t solve the problem of the massive emissions that result when hydrogen is made from methane or the lack of hydrogen refueling infrastructure. It may be that fuel cells never see wide acceptance for private passenger cars but they could well play a role in reducing emissions from airplanes, heavy equipment, and ships, especially if the cost of fuel cells falls dramatically because of breakthroughs like this one.

We’re not ready to fully embrace fuel cells, but we are certainly happy to learn of any new technology that lowers carbon emissions from the transportation sector.