
Platinum-free fuel cells could make electromobility cheaper
The discussion about electric vehicles is mostly focusing on battery electric vehicles. However, the fuel cell technology could offer an interesting alternative, at least in theory. In practice, fuel cells are simply too expensive (even more expensive than the large lithium-ion batteries needed to store enough electric energy to run a car). This could potentially change if a new catalyser material for fuel cells can be industrialised: It enables building fuel cells without catalysers that contain platinum. Waiving the noble metal could make fuel cells significantly cheaper.
Researchers from Technische Universität Darmstadt (Germany) and the Helmholtz Zentrum Berlin (HZB) have developed and evaluated an inexpensive catalyser material for fuel cells. Consisting of so called iron-nitrogen complexes (FeN4-centres) embedded in graphene “islands” the size of a few nanometres, it would make the use of expensive platinum as catalyser material redundant. According to the researchers, the FeN4 centres have an “excellent catalytic effect” that is almost at the same level as platinum.
Fuel cells transform the chemical energy bound in hydrogen (H2) into electric energy through a process known as cold combustion. In this process, the hydrogen is reacting with oxygen, setting free the electric energy. To enable cold combustion, the electrodes of the fuel cell need to be coated with a highly active catalyser material – such as platinum. As a cheaper alternative, so-called Fe-N-C catalysers are under investigation. It however remained unclear to which extend inorganic admixtures can negatively affect the catalyser effect. Such admixtures can happen inadvertently during the production process.
The research teams now have developed a cleaning process that can significantly reduce the content of interfering metallic compounds. In parallel with the reduction of such compounds the activity of the catalyser is rising.
The results of these research works could make it possible to create a completely regenerative energy cycle in which hydrogen generated by solar energy could be converted emission-free into cost-effective fuel cells, the researchers conclude.
For more information contact kramm@ese.tu-darmstadt.de
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