14th September 2007

Daihatsu, the Japanese minicar manufacturer recently (September 2007) announced some results on its research into alkaline fuel cells.

Alkaline fuel cells themselves are not a particularly new technology, having been used in a number of space programmes since the 1950s. Although this type of fuel cell has a different chemistry to other types of fuel cell and can use cobalt and other materials as the catalyst for the fuel cell reaction, platinum is also very effective for this reaction. Alkaline fuel cells have previously therefore been developed using either base metal or precious metal catalysts.

Almost all car manufacturers are working on the possibility of using fuel cells to provide primary power in their vehicles and the main technology under investigation is the proton exchange membrane fuel cell. These operate at a higher temperature than alkaline fuel cells and are therefore less susceptible to loss of performance through poisoning. They have demonstrated better durability and reliability than alkaline fuel cells to date. Proton exchange membrane fuel cells also have a higher power density, an important aspect when fitting a fuel cell engine into a vehicle. This type of fuel cell uses platinum as the catalyst and this is unaffected by the Daihatsu announcement.

At the moment, Daihatsu's alkaline fuel cell project appears to be in its early stages and no commercial product would be expected for some time. This technology is likely to be most suitable for small, limited range vehicles, where performance and durability requirements are not as stringent as for mass transport. Proton exchange membrane fuel cell vehicles have been tested for far longer and are further developed. Although more development work will be required before they become commercial - for instance in the minimisation of platinum loading - they are more likely to represent the typical future mass market product.