Brussels, 17 Feb 2006
More efficient fuel cells will soon be possible thanks to research carried out in Sweden by the Royal Institute of Technology in Stockholm (KTH), Uppsala University and Linköping University. These fuel cells are a priority for research because they can convert simple raw materials - hydrogen and oxygen - into electricity, with no polluting by-products other than water.
The team used quantum mechanics to examine the relationship between atomic structure and capacity to conduct oxygen ions. This is important because fuel cell efficiency relies upon the ability of materials to transport oxygen ions The quicker the transport of oxygen ions, the greater the efficiency of the cell. Their paper, published in the Proceedings of the National Academy of Sciences of America, states that the, 'results reveal a remarkable correspondence between vacancy properties at the atomic level and the macroscopic ionic conductivity.'
The team's research focused on the material cerium oxide. The efficiency of this substance as a conduit for oxygen ions is altered by the addition of tiny quantities of contaminants, known as dopants. Some of these dopants can increase the efficiency of the material greatly.
Rather than trial-and-error researching, which is slow and costly, the team used quantum modelling techniques to rapidly test materials. 'The methods we use to theoretically calculate an element's capacity to conduct ions enable us to test many more substances than before. Even though the calculations take considerable time, it is both faster and cheaper than testing all of these materials in practice,' says David Andersson from KTH.
More efficient materials also mean that fuel cells will work at lower temperatures. Current cells operate at around 1,000 degrees centigrade. 'With other electrolyte materials than those we have today, the working temperature and thereby the cost of the materials surrounding the fuel cells could be brought down. Lower temperatures would also open up the possibility of portable variants of fuel cells,' says Andersson.