03 Apr 04. The Financial Times reported on April 3rd that, ‘Fuel cells have been touted as the clean, green energy source of the future by no less a proponent than George W.Bush.’
However, many problems with the construction of such cells remain. Researchers in Scotland believe they have solved one of the most troublesome limitations of current fuel cells, by developing a new material for use as an anode in the cells. They report their work in the May edition of Nature Materials.
Fuel cells work by converting chemical energy directly into electrical energy with high efficiency and low emissions. Research has concentrated on hydrogen as the optimum fuel but it can be costly to extract and tricky to store. Therefore work also continues on high-temperature fuel cells using hydrocarbons such as methane or alcohols such as methanol, which will still be cleaner than today’s conventional carbon-based fuels.
These high-temperature cells tend to use anodes made of nickel and a substance known as yttria-stabilised zirconia, as these materials combine good catalytic properties and conduct current efficiently. Unfortunately, they also tend to collect carbon and sulphur deposits from the fuel, which makes them less efficient.
The new anode from Scotland uses no nickel, relying instead on a perovskite nickel-free anode, which resists chemical deposits during methane exposure but has comparable performance to conventional materials.
The new anode should also allow fuel cells to operate at intermediate temperatures of between 500°C and 700°C, which are lower than for conventional fuel cells of this type, and should make the fuel cells themselves much smaller. Such systems could provide heating and electricity for buildings, or provide power for electric windows or air-conditioning in vehicles. School of Chemistry, University of St Andrews, Fife, Scotland, UK; tel: +44 (0)1334 476 161; www.st-andrews.ac.uk