Researchers in Korea have increased the efficiency of polymer electrolyte membrane (PEM) fuel cells by about 10%.

Sejin Kwon and colleagues at the Korea Advanced Institute of Science and Technology, Daejeon, used the decomposition of hydrogen peroxide to provide the heat needed to drive the production of hydrogen from methanol.

PEM fuel cells produce electrical energy from hydrogen and oxygen. But since hydrogen has such a low energy density when stored as a gas, it is often stored indirectly as a liquid fuel, such as methanol. Hydrogen is produced from the methanol as required in a process called 'steam reforming', but as this process is endothermic a heat source is also needed.

Kwon made a compact methanol reformer that uses the decomposition of hydrogen peroxide as the heat source. One of the key features of the reformer is that the products of the reaction, water vapour and oxygen, are then 

recycled. The water vapour is used for the steam reforming and the oxygen to oxidise any carbon monoxide produced during methanol reforming and also to supplement the oxygen from the air in the fuel cell itself. Furthermore, this oxygen enrichment boosts the efficiency of the fuel cell.

The researchers envisage the use of such a system as substitutes for batteries in mobile applications.

Madelaine Chapman