October 9, 2008
Goretex Rescues Fuel Cells
Monash University has demonstrated that Goretex can replace platinum in fuel cells, potentially revolutionising pollution-free transport. The announcement comes as a geochemist warns that global reserves of platinum are inadequate to support the mass production of hydrogen fuel cell cars. Hydrogen fuel cells offer the theoretical possibility of eliminating tailpipe pollution. Provided the hydrogen is produced using clean energy sources, cars driven by hydrogen fuel cells would be almost carbon-neutral as well. However, one obstacle to dieir adoption is the need to use platinum as a catalyst.With prices fluctuating wildly but reaching as high as $81,000/ kg this year, platinum makes fuel cells containing it highly expensive. The platinum alone in a fuel cell costs more than an entire gasoline engine of equivalent power.
Australian National University geochemist John Mavrogenes expects this to get worse, noting: "Existing reserves would meet less than 20% of the world's platinum demand if all cars went hydrogen".
Mavrogenes is addressing this by studying the ways that platinum can be deposited in order to find new deposits in previously unsuspected places. Three deposits supply 80% of the world's platinum, with only one other large reserve confirmed, so our knowledge of platinum-containing rocks is limited. But by simulating the crustal magma from which platinum is deposited, Mavrogenes hopes to find previously unsuspected platinum reserves.
However, Monash research published in Science on 1 August may make his work less urgent. Dr Bjorn Winther-Jensen has used material better known for its resistance to moisture to remove the need for platinum in fuel cells. Winther-Jensen has deposited a layer of conductive plastic 1/100th of the thickness of a human hair on a layer of Goretex. The plastic acts as both a catalyst and electrode.
"The same way as waste vapour is drawn out of this material to make hikers more comfortable, so it is able to 'breathe' oxygen into our fuel cell and into contact with the conductive plastic," Dr WinterJensen says.
Goretex is already used for medical implants and cable insulation, so its use in fuel cells is not as big a jump as it may first appear. And besides the cost advantages, plastic/Goretex fuel cells do not appear to suffer the same carbon monoxide degradation that plagues platinum cells.
Prof Maria Forsyth, Director of Monash's Centre for Excellence for Electromaterials Sciences, says that Winther-Jensen's cell is "more economical, more easily sourced, outlasts platinum cells and is just as effective."
Fuel cells using Goretex instead of platinum may make hydrogen cars viable.
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