Lightweight alloy boost for hydrogen fuel tanks
A Dutch-backed researcher claims to have moved a step closer to everyday use of hydrogen for powering vehicles with the discovery of an alloy of magnesium, titanium and nickel that could be used to make a storage tank weighing less than half as much as an equivalent battery pack.
In a project funded by the Netherlands research agency as part of the country’s ‘Sustainable Hydrogen’ programme, Robin Gremaud made what he claims is the first use of a method for simultaneous testing of thousands of samples of different metals for their capacity to absorb hydrogen.
The technique is based on the phenomenon of ‘switchable mirrors’ discovered about ten years ago when researchers at the VU University Amsterdam realised that certain materials lose their reflection when they absorb hydrogen. Known as hydrogenography, or ‘writing with hydrogen’, it allows scientists to simultaneously analyse the efficacy of thousands of different combinations of metals.
The test required each of the three metals to be layered onto sections of transparent film in different ratios using sputtering deposition. When the film is exposed to different amounts of hydrogen, it is clearly visible, even to the naked eye, which is best at absorbing hydrogen.
Gremaud claims that a vehicle storage tank constructed using the optimum combination of metals and able to carry enough hydrogen for a 400km journey would weigh 200kg. An electric car like a Toyota Prius would need 317kg of lithium batteries for the same trip, he says.
Although this new metal alloy is important for the development of hydrogen as a fuel, Gremaud admits that the discovery of the holy grail of hydrogen storage is “still some way off”. Prospects for hydrogenography look bright though. British company Ilika has expressed interest in building a hydrogen analyser based on the technique.