Cactus Inspires Potential Fuel-Cell Improvement

A new type of membrane inspired by the desert cactus has the potential to significantly boost the performance of fuel cells and transform the electric-vehicle industry, Australian and Korean researchers contend.

The scientists from Australia’s Commonwealth Scientific and Industrial Research Organization and Korea’s Hanyang University say that in hot conditions the membrane, which has a water-repellent skin, can improve fuel cells’ efficiency by a factor of four.

CSIRO researcher Aaron Thornton says the skin works in a similar way to a cactus plant, which thrives by retaining water in harsh and arid environments.

“Fuel cells, like the ones used in electric vehicles, generate energy by mixing together simple gases, like hydrogen and oxygen,” Thornton says in a statement. “However, to maintain performance, proton-exchange-membrane fuel cells – or PEMFCs – need to stay constantly hydrated.”

The researchers achieved this by placing the cells alongside a radiator, water reservoir and a humidifier.

“The downside is that when used in a vehicle, these occupy a large amount of space and consume significant power,” Thornton says.

However, CSIRO researcher Cara Doherty says the team’s new cactus-inspired solution offers an alternative.

“A cactus plant has tiny cracks, called stomatal pores, which open at night when it is cool and humid, and close during the day when the conditions are hot and arid,” Doherty says. “This helps it retain water.”

The new membrane works in a similar way: Water is generated by an electrochemical reaction, which then is regulated through nano-cracks within the skin. The cracks widen when exposed to humidifying conditions and close up when it is drier.

“This means that fuel cells can remain hydrated without the need for bulky external humidifier equipment,” Doherty says. “We also found that the skin made the fuel cells up to four times as efficient in hot and dry conditions.”

Hanyang’s Young Moo Lee, the project leader, says this could have major implications for many industries, including the development of EVs.

“At the moment, one of the main barriers to the uptake of fuel-cell electric vehicles is water management and heat management in fuel cell systems,” Lee says. “This research addresses this hurdle, bringing us a step closer to fuel-cell electric vehicles being more widely available.”