Devices capable of storing hydrogen more safely for use in automotive fuel cells are being developed using nanometre-sized metal particles created at the UK’s first specialist production centre.
The centre, established by Qinetiq Nanomaterials, contains two plasma vaporisers, each capable of producing several kilograms of nanoparticles per hour.
The company plans to use the vaporisation process to develop metal alloys for use as hydrogen storage materials, said commercial director Dr Michael Pitkethly.
Although many have questioned whether the hydrogen economy will become a reality, the fuel cell industry is actively investigating the use of metal hydrides as a safer and more compact method of carrying hydrogen on a vehicle than storing it in liquid form, said Pitkethly.
Metal alloys can bond with hydrogen under high pressure to form hydrides and can therefore be used as hydrogen storage devices. When the gas is needed to power the fuel cell, the material is heated or the pressure reduced.
But standard metal alloys can store only around one to two per cent hydrogen gas by weight,making them expensive to use. So the Qinetiq researchers are studying a variety of metal alloy nanoparticles, which they believe will increase the storage capacity of hydrides to around seven per cent.
‘If we can get the capacity up to six or seven per cent it becomes much more commercially viable, as the amount of material you need for the hydrogen is much lower, and the vehicle can travel further without needing to be refuelled,’ said Pitkethly.
To create the nanoparticles a feedstock of original material is introduced into a chamber where it comes into contact with extremely hot plasma, or ionised gas, and vaporises. The vapour is then rapidly cooled using a cold, inert gas, causing the material to quickly condense and solidify to form nanometre-sized powder particles. The process can be used to produce metal and metal alloy nanoparticles, as well as oxides, nitrides and carbides.
Qinetiq is looking at around 25 projects involving nanomaterials developed at the centre, including the use of tungsten nanoparticles in explosive charges for the oil and gas industry. Using nanoparticles could significantly improve the ability of the explosives to fracture rock, said Pitkethly.
‘The rock fractures for a larger distance, and it is easier to get a better flow [of oil or gas] out of the rock if you can penetrate deeper,’ he said.