Textiles could help cut world's output of carbon dioxide from cars

18 January 2009, Melbourne - Researchers at Monash University in Melbourne have revolutionised the design of a fuel cell that could make hybrid cars more reliable and cheaper to build and help reduce carbon dioxide emissions. Goretex is the high-tech clothing material worn by mountaineers and polar adventurers but now the Monash scientists have made a fuel cell with it that could cut the world's output of carbon dioxide from cars.

The breakthrough came about through the design of a fuel cell in which a specially coated form of Goretex is the key component. A fine layer of highly conductive plastic, a mere 0.4 of a micron thick or about 100 times thinner than a human hair, was deposited on the breathable fabric as part of a fuel cell with electrodes and a catalyst.

Just as waste water vapour is drawn out of the Goretex to make hikers more comfortable and less prone to hypothermia; it is also able to 'breathe' oxygen into the fuel cell and into contact with the conductive plastic. One of the researchers, Professor Doug MacFarlane, said the discovery was probably the most important development in fuel cell technology in the last 20 years.

MacFarlane is a chief investigator with the Australian Centre of Excellence for Electromaterials Science. He said the benefits for the motoring industry and for motorists were that the new design removed the need for platinum, which is the catalyst and is currently central to manufacturing fuel cells.

But reliance on platinum was making the likelihood of using fuel cells in everyday passenger cars increasingly improbable. Although platinum electrodes are highly effective in fuel cells, the metal is costly and scarce. As well, the platinum particles in composite electrodes tend to become inactive after contact with carbon monoxide which is usually present when motor fuels are burnt.

"The cost of the platinum component alone in current fuel cells for a small car with a 100kW electric engine is more than the total cost of the car's petrol engine", MacFarlane said. "Also, the current annual world production of platinum is only enough to supply about 3 million 100kW cars, a fraction of the current annual global production of these vehicles."

He said the new fuel cell using Goretex had been tested for up to 1,500 hours continuously using hydrogen as the energy source, with no effect on the Goretex electrode or deterioration in performance. The tests confirmed that oxygen conversion rates were comparable with platinum-catalysed electrodes and the Goretex electrodes were not poisoned by carbon monoxide as was platinum.

Fuel cell hybrid cars are driven by an electrical motor which either runs from a battery or from electricity generated by a fuel cell. The cell takes in fuel and air, and produces electricity so the Monash researchers would need to design one that could produce 100Kw of power to drive a small car.

"The concept is like a battery: the cell has two electrodes with an electrolyte bridging the gap while the fuel could be hydrogen, methanol, ethanol or even glucose," MacFarlane said. "Hydrogen is the best because the product of the chemical reaction in the cell is just water and no carbon dioxide is released as it would be with the other fuels."

The big challenge now is deciding on the best fuel and deciding how hydrogen could be produced and distributed so cars would be able to fill up with the gas, rather than liquid fuels. MacFarlane said the long-term goal would be to use solar electricity to split water into hydrogen and oxygen whereas using electricity from coal-fired generators would only produce more CO2.