A new type of membrane, inspired by cactus, may significantly boost the performance of fuel cells, and transform the electric vehicle industry.
The membrane was developed by scientists from CSIRO and Hanyang University in Korea. The membrane works like a cactus plant, particularly its ability to thrive by retaining water in harsh and arid environments.
Similarly, during hot conditions, the water-repellent membrane can improve the efficiency of fuel cells by a factor of four.
According to CSIRO researcher Dr Aaron Thornton, this efficiency boost is due to the membrane's ability to keep the fuel cells hydrated.
"Fuel cells, like the ones used in electric vehicles, generate energy by mixing together simple gases, like hydrogen and oxygen," Dr Thornton explained.
"However, in order to maintain performance, proton exchange membrane fuel cells - or PEMFCs - need to stay constantly hydrated."
While currently PEMFCs are kept hydrated by placing the cells alongside a radiator, water reservoir, and a humidifier, these occupy a large amount of space and consume significant power.
The membrane is an alternative means of keeping the PEMFCs hydrated, and work via a mechanism directly inspired by the stomatal pores found on the skin of the cactus plant.
These stomatal pores open up at night when it is cool and humid, but close during the hot and arid daytime, so the moisture gathered during the night can be retained.
"This membrane works in a similar way. Water is generated by an electrochemical reaction, which is then regulated through nano-cracks within the skin," said Dr Thornton.
"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."
By using the skin, the researchers managed to boost the efficiency of the fuel cells up to four times compared to conventional equipment during hot and dry conditions.
The research could have implications for many industries, and also make it cheaper and easier to manufacture electric vehicles, since one of the main barriers to the uptake of fuel cell electric vehicles is water and heat management for the fuel cell systems.
This technique could also be applied to other existing technologies that require hydrated membranes, including devices for water treatment and gas separation.