Simulations Advance Understanding of Magnesium-Based Hydrogen Storage Materials

JOM, Aug 2008

Researchers at Uppsala University, Sweden, have demonstrated an atomistic mechanism of hydrogen release in magnesium nanoparticles-a potential hydrogen storage material. The findings have been published in the June 11 online edition of Proceedings of the National Academy of Science.

The hydrogen fuel cell is an attractive alternative energy technology, primarily because hydrogen is among the most abundant elements on earth. Hydrogen is also capable of producing energy through chemical reactions with oxygen in fuel cells, releasing only water as its by-product. Storing hydrogen gas in a compact way, however, is still an unsolved problem.

To address this issue, much research has been directed at absorbing hydrogen in metal powders, forming so-called metal hydrides, according to a June 16 statement issued by Uppsala University, Sweden. The statement noted that magnesium may absorb up to 7.7 weight percent of hydrogen and has commonly been studied for this purpose, especially since fast loading and unloading of hydrogen can be accomplished by adding catalysts like iron and nickel particles.

The Uppsala researchers indicated that it has been speculated that the catalysts act as shuttles, helping to transport hydrogen out of the material. With the help of computer simulations of magnesium clusters at the quantum mechanical level, the Uppsala team has now been able to show on an atomic scale how this happens and why only a small amount of catalysts are necessary to improve the hydrogen release. The simulations were performed at Uppsala University's Multidisciplinary Center for Advanced Computational Science.

"We expect the findings to aid further technical improvements of magnesium-based hydrogen storage materials, as well as other related light metal hydrides," said Raajev Ahuja, lead researcher.