'Iron veins' could be key to hydrogen storage in vehicles

Their idea is to create molecular-scale ‘veins’ of iron permeating grains of magnesium, much like a network of capillaries. According to NIST, the iron veins may transform magnesium from a promising candidate for hydrogen storage into a real-world solution.

Hydrogen has been touted as an alternative to petrol but the lack of a safe, fast way to store it on board a vehicle has been seen as a drawback.

According to NIST materials scientist Leo Bendersky, iron-veined magnesium could overcome this hurdle.

The combination of lightweight magnesium laced with iron could rapidly absorb and release sufficient quantities of hydrogen so that grains made from the two metals could form the fuel tank for hydrogen-powered vehicles.

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

Grains of pure magnesium are said to be effective at absorbing hydrogen gas, but only at high temperatures and pressures — conditions that let them store enough hydrogen to power a car for a few hundred kilometres.