One of the biggest obstacles to using clean-burning hydrogen in cars and fuel cells is finding a way to safely and conveniently store the explosive gas.

New research by VU University Amsterdam has shown that one of the best storage media may be a lightweight alloy of magnesium, titanium and nickel.

A decade ago, researchers at the VU discovered that certain materials lose their reflection by absorbing hydrogen.

Mirror, mirror on the wall, who is the lightest of them all?

A technique known as 'switchable mirrors' enabled them to test thousands of different metals for absorption efficiency, resulting in the discovery of an alloy that enables hydrogen tanks to be up to 60 per cent lighter than equivalent batteries.

Driving four hundred kilometres with a Toyota Prius, for instance, would require 317Kg of modern lithium batteries. With the new alloy, the same distance need a hydrogen tank of only 200Kg.

The British company Ilika in Southampton wants to build a hydrogen analyser using the new technique, although researchers warn that the discovery of the 'holy grail' of hydrogen storage is still "some way off".