Iron ‘Veins’ Are Secret of Promising New Hydrogen Storage Material

[OKIsItJustMe]

http://www.nist.gov/mml/metallurgy/hydrogen-083011.cfm

Iron ‘Veins’ Are Secret of Promising New Hydrogen Storage Material

From NIST Tech Beat: August 30, 2011

With a nod to biology, scientists at the National Institute of Standards and Technology (NIST) have a new approach to the problem of safely storing hydrogen in future fuel-cell-powered cars. Their idea: molecular scale "veins" of iron permeating grains of magnesium like a network of capillaries. The iron veins may transform magnesium from a promising candidate for hydrogen storage into a real-world winner.

…

"Powder grains made of iron-doped magnesium can get saturated with hydrogen within 60 seconds," says Bendersky, "and they can do so at only 150 degrees Celsius and fairly low pressure, which are key factors for safety in commercial vehicles."

Grains of pure magnesium are reasonably effective at absorbing hydrogen gas, but only at unacceptably high temperatures and pressures can they store enough hydrogen to power a car for a few hundred kilometers—the minimum distance needed between fill-ups. A practical material would need to hold at least 6 percent of its own weight in hydrogen gas and be able to be charged safely with hydrogen in the same amount of time as required to fill a car with gasoline today.

The NIST team used a new measurement technique they devised that uses infrared light to explore what would happen if the magnesium were evaporated and mixed together with small quantities of other metals to form fine-scale mixtures. The team found that iron formed capillary-like channels within the grains, creating passageways for hydrogen transport within the metal grains that allow hydrogen to be drawn inside extremely fast. According to Bendersky, the magnesium-iron grains could hold up to 7 percent hydrogen by weight.

…

http://dx.doi.org/10.1016/j.ijhydene.2011.04.196

[Nihil]

1. Am I reading that right?

> "Powder grains made of iron-doped magnesium can get saturated with hydrogen
> within 60 seconds," says Bendersky, "and they can do so at only 150 degrees
> Celsius and fairly low pressure, which are key factors for safety in commercial
> vehicles."

They have to heat the magnesium/iron powder to upwards of 150C to refuel?

I recognise that the autoignition temperature of hydrogen is quite a bit higher
(500C) but still ...

:wow: