Graphene breakthrough gives scientists hope for energy revolution
A device that uses the atmosphere to generate clean electricity could one day be a reality after British scientists discovered a critical weak spot in the toughest membrane on the planet.
In a discovery that could revolutionise fuel cell technology, the researchers found that graphene - the world's thinnest, strongest and most impermeable material - can allow protons to pass through it.
The researchers, led by Nobel prize winner and graphene discoverer Andre Geim of Manchester University, said the finding also raised the possibility that, in future, graphene membranes could be used to "sieve" hydrogen gas from the atmosphere to generate electricity.
"We are very excited about this result because it opens a whole new area of promising applications for graphene in clean energy harvesting and hydrogen-based technologies," co-researcher Marcelo Lozada-Hidalgo said.
Graphene, just one atom thick and 200 times stronger than steel, was first isolated in 2004 by Geim and fellow researchers, who were awarded a Nobel Prize in 2010 for their work.
It is renowned for being impermeable to all gases and liquids - giving it the potential for a range of uses like corrosion-proof coatings, impermeable packaging and even super-thin condoms.
Knowing graphene is impermeable to even the smallest of atoms, hydrogen, Geim's team tested whether protons - or hydrogen atoms stripped of their electrons - were also repelled. Their work was published in the journal Nature.
Against expectations, they found protons could pass through the ultra-strong material fairly easily, especially at raised temperatures and if the graphene films were covered with nanoparticles such as platinum, which acts as a catalyst.
Geim and Lozada-Hidalgo said this meant graphene could be used in proton-conducting membranes, a crucial component of fuel cell technology.
Already utilised in some modern cars, fuel cells use oxygen and hydrogen and convert the input chemical energy into electricity. But the fuels leak across existing proton membranes, "poisoning" the process and reducing cell efficiency - which Geim said could be overcome with graphene.
The team also found graphene membranes could be used to extract hydrogen from the atmosphere, suggesting the possibility of combining them with fuel cells to make mobile electric generators powered just by tiny amounts of hydrogen in the air.
"Our (study) provides proof that this kind of device is possible," Geim said.