Scientists at Monash University in Australia have developed ultra-thin membranes that enable hydrogen fuel cells to operate at 482 °F (250 °C). This allows membranes to operate without water, removing a major bottleneck to the use of fuel cells and enabling rapid, large-scale deployment of these clean energy systems. 

As countries look for options beyond fossil fuels, fuel cells become the obvious choice. Powered by hydrogen, these cells do not release any carbon into the environment during usage, with water and heat being their only byproducts. 

Unlike solar and wind power, fuel cells can be deployed on demand and power a wide range of applications, from data centers to space missions, passenger vehicles to airplanes. Fuel cells are lightweight and portable, but limits on their performance have slowed their adoption. 

Water-dependent systems

Membranes in fuel cells perform the most important function of transporting protons. However, these membranes rely on water to do this job. Since water evaporates at higher temperatures, fuel cells have struggled to operate at these temperatures, limiting their usage as well. 

Researchers at the University of Monash addressed this problem head-on by developing atomically thin nanosheets that do not need water for proton transport. While nanosheets have been made before, they too faced poor proton transport issues between their layers. To resolve this, the researchers used nanoconfined phosphoric acid in their sheets. 

Made from graphene and boron nitride, these membranes delivered exceptionally high power output in hydrogen fuel cells. 

Highly efficient membrane

“By integrating proton-conducting nanosheets with nanoconfined phosphoric acid, we have created a membrane that maintains fast proton transport without relying on water,” said Huanting Wang, a professor at the Department of Chemical and Biological Engineering at Monash University. “This enables fuel cells to operate efficiently at much higher temperatures than is currently possible.”

In the laboratory tests, the researchers demonstrated ultrafast proton transport inside this membrane at temperatures as high as 482 Fahrenheit (250 degrees Celsius). This is likely to open up the use of fuel cells in transport and heavy industry, as well as in more clean energy systems, in the near future.  

“The nanosheets provide direct proton transport pathways, while the confined phosphoric acid enables rapid proton hopping,” added Kaiqiang He, a postdoctoral research fellow at Monash University, who was involved in the work. “Together, these mechanisms deliver both high conductivity and stability under dry, high-temperature conditions.”

Interestingly, the membrane worked well even when concentrated methanol was used as a fuel. This demonstrates its superior performance, even under harsh conditions. The researchers are confident that their work has addressed a long-standing barrier in membrane design, one that will help the development of high-temperature electrochemical systems. 

The membrane will also find applications beyond fuel cells, where it could be used for splitting water, reducing carbon dioxide, and synthesizing ammonia. The nanosheets, along with nanoconfined proton carriers, also open up opportunities for future proton-conducting materials.

The research findings were published in Science Advances.